Sustainable Development of Water and Environment (Environmental Science and Engineering) 3031425871, 9783031425875

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Environmental Science and Engineering

Han-Yong Jeon   Editor

Sustainable Development of Water and Environment

Environmental Science and Engineering Series Editors Ulrich Förstner, Buchholz, Germany Wim H. Rulkens, Department of Environmental Technology, Wageningen, The Netherlands

The ultimate goal of this series is to contribute to the protection of our environment, which calls for both profound research and the ongoing development of solutions and measurements by experts in the field. Accordingly, the series promotes not only a deeper understanding of environmental processes and the evaluation of management strategies, but also design and technology aimed at improving environmental quality. Books focusing on the former are published in the subseries Environmental Science, those focusing on the latter in the subseries Environmental Engineering.

Han-Yong Jeon Editor

Sustainable Development of Water and Environment

Editor Han-Yong Jeon Department of Chemical Engineering Inha University Incheon, Korea (Republic of)

ISSN 1863-5520 ISSN 1863-5539 (electronic) Environmental Science and Engineering ISBN 978-3-031-42587-5 ISBN 978-3-031-42588-2 (eBook) https://doi.org/10.1007/978-3-031-42588-2 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland Paper in this product is recyclable.

Organizing Committee

Conference Chairs Prof. Han-Yong Jeon, Inha University Prof. Peiyue Li, Chang’an University

Program Committee Chair Prof. John Zhou, University of Technology, Sydney

Program Co-chair Assoc. Prof. Xiaosheng Qin, Nanyang Technological University

Local Chair Asst. Prof. Hugo Wai Leung Mak, The Chinese University of Hong Kong and The Hong Kong University of Science and Technology

Technical Program Committee Prof. Azmi Bin Aris, Universiti Teknologi Malaysia Assoc. Prof. Elanur Adar, Artvin Coruh University

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Organizing Committee

Assoc. Prof. Mohd Azmuddin Abdullah, FABSc Universiti Putra Malaysia Asst. Prof. Amimul Ahsan, Universiti Putra Malaysia Dr. Kaveh Ostad-Ali-Askari, Isfahan University of Technology Dr. Zulfiqar Ahmad, Wuhan University Dr. Catarina L. Amorim, Universidade Católica Portuguesa Prof. Byungik Chang, University of New Haven Dr. Mohammad Hadi Dehghani, Tehran University of Medical Sciences Assoc. Prof. Murat Eyvaz, Gebze Technical University Dr. Daniel Jato Espino, University of Cantabria Dr. Hadi Erfani, Payame Noor University Dr. Yasser Nabil Elhenawy, Port Said University Asst. Prof. Alemu Gizaw, Adama Science and Technology University Assoc. Prof. Hassimi bin Abu Hasan, Universiti Kebangsaan Malaysia Assoc. Prof. Tony Hadibarata, Curtin University Asst. Prof. Sam Hsien-Yi Hsu, City University of Hong Kong Prof. Ihsan Flayyih Hasan AI-jawhari, University of Thi-Qar Prof. Ismail Rakip Karas, Karabük University Assoc. Prof. Ignacy Kitowski, University College of Applied Sciences in Chelm Prof. Teik-Thye Lim, Nanyang Technological University Prof. Fei Li, Zhongnan University of Economics and Law Assoc. Prof. Ana Matin, University of Zagreb Faculty of Agriculture Asst. Prof. Amin Mojiri, Hiroshima University, Hiroshima Prof. Shou-Qing Ni, Shandong University Assoc. Prof. Jaan H. Pu, University of Bradford Dr. Ivana Plazoni´c, University of Zagreb Faculty of Graphic Arts Dr. Sofia I. A. Pereira, Universidade Católica Portuguesa Prof. Yujia Song, Changchun Sci-Tech University Asst. Prof. Pouya Samani, Maastricht University Dr. Tiziana Susca, Polytechnic Federal Institute for Materials Research and Testing Dr. Yujia Song, Jilin Normal University Dr. Mahdi Sedighkia, ANU College of Science Prof. Sang-Bing Tsai, University of Electronic Science and Technology of China Prof. Chih-Ta Tsai, National Cheng Kung University Dr. Grzegorz Woroniak, Bialystok University of Technology Prof. Zhao Xin, Northeastern University Assoc. Prof. Foo Keng Yuen, Universiti Sains Malaysia

Preface

Dear Colleagues, 2023 The 6th international conference on Sustainable Development of Water and Environment has been successfully held on June 18–19, 2023, Hong Kong, China. In past five years, ICSDWE has been taken place in Northeastern University, China (2018), Hong Kong, China (2019), Inha University, South Korea (2020) and Webinar (2021 and 2022). The proceedings contains papers submitted to 6th ICSDWE. The main purpose of this conference is to exchange some of the latest research findings and educational information on the water and environment in order to take important measures to protect water resources and the environment for future generations in accordance with the principles of sustainable development. All submissions were peer-reviewed through a double-blind review process by an international panel of at least two international expert referees, and decisions were taken based on research quality. We are very pleased to report that the quality of the submissions this year turned out to be very high. This conference proceedings covers Water Resources Management, Water and Wastewater Treatment, Sustainable Development of Water, Environmental Science, Environmental Sustainability, etc. We would like to extend our most sincere thanks to everyone involved in ICSDWE2023. It was the participation of these experts that made the conference a success. We also express our sincere gratitude to the organizing committee for their valuable guidance on the conference organization and peer review of the papers. We are confident that ICSDWE2023 has provided an excellent forum for discussion, fostering new ideas and collaborative research.

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Preface

Finally, once again thank you for joining this conference, and we are looking forward to seeing you in the next ICSDWE. Incheon, Korea (Republic of)

Prof. Han-Yong Jeon ICSDWE General Chair On behalf of ICSDWE2023 Committee

Contents

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3D Continuous and Discrete Models of Multicomponent Suspended Transport for Coastal Marine Systems: Research and Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Valentina V. Sidoryakina, Alexander I. Sukhinov, Alexander E. Chistyakov, and Inna Yu. Kuznetsova

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Direct and Indirect Ultrasonic-Assisted Preparation of Calcium Alginate Monolithic Pellets for the Removal of Methylene Blue from Aqueous Solution . . . . . . . . . . . . . . . . . . . . . . . Jia Jun Isaac Yong, Voon-Loong Wong, Swee Pin Yeap, Siew Shee Lim, and Nurul Husna Mohd Yusoff

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Experimental Study on Sludge Depth Drying Under Dual Physical Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yuekan Zhang, Mingyuan Xu, Wei Hu, Qingyun Zhang, and Jiangbo Ge Challenges of the Water Crisis in the Arab Gulf Countries (2011–2021) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sura Taha Al-Qasiem Al-Harahsheh and Mohammed Torki Bani Salameh Learned Lessons from Japanese Experiences in Planning and Managing Fishing Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mahmoud Sharaan, Moheb Iskander, Kazuo Nadaoka, Abdelazim Negm, and Mona G. Ibrahim Study of the Influence of Pipeline Sediment on Drainage Capacity Based on SWMM and GSC Coefficients . . . . . . . . . . . . . . . . Fuchen Ban, Hong Ai, and Mingxuan Zhang

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Contents

Sr/86 Sr Tracer for the Formation and Evolution of Deep Underground Brines in Sedimentary Basins . . . . . . . . . . . . . . . . . . . . . Hang Ning, Wanjun Jiang, Futian Liu, Jing Zhang, Sheming Chen, and Zhuo Zhang 87

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Motion of the Thermal in Static Thermal-Stratified Water . . . . . . . . Bo Chen

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Water Under Pressure—A Model for Evaluating the Impact of Economic Growth on Water Resources . . . . . . . . . . . . . . . . . . . . . . . . Desislava Botseva, Nikola Tanakov, and Georgi Nikolov

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10 Mineral Water Resources Management in the Bulgarian Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 Veselina Lyubomirova, Elka Vasileva, and Georgi Tsolov 11 Improving the Quality of Public Transport to Achieve Environmental Sustainability in the City of Sofia, Bulgaria . . . . . . . . 123 Elenita Velikova and Iliya Gatovski 12 River Healthy Assessment in Developing Countries—A Case Study on Yellow River . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 Yuansheng Zhang, Zhiwei Cao, Xin Jin, and Guojie Liang 13 Assessment on Recreational Value of the Liming Scenic Spot of Laojun Mountain in Lijiang, China . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 Junmei Li, Pengfei Wang, Guoqi Qian, Runqiu Fei, Yu Fei, Jing Zhou, Jianmei Fu, and Zhidan Deng 14 The Study on Sustainable Protection and Development of Huizhou Ancient Road Cultural Ecology Resources from Ecological Perspective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 Bi Zhongsong, Zhang Xiao, Li Yunzhang, Cheng Peng, and Zhang Huizhen 15 Effects of Polypropylene Fibers from Single-Use Facemasks on the Microstructure of Normal Cementitious Composites . . . . . . . 183 Aaron Paul I Carabbacan and Teodoro A. Amatosa 16 Advancements in Concrete Incorporation: Harnessing the Potential of Crumb Rubber Tires as Sustainable Alternatives to Fine Aggregates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195 Franklyn F. Manggapis, Sanjie Dutt A. Kumar, Joe Robert Paul G. Lucena, Aaron Paul I. Carabbacan, and Orlean G. Dela Cruz 17 Water Quality Characteristics in the Source Areas of Yangtze River and Lancang River in Wet Season, in Tibet Plateau . . . . . . . . . 207 Min Liu, Cheng Han, Liangyuan Zhao, Huawei Huang, Yuting Zhang, Yuan Hu, Wei Deng, Shengfei Deng, and Mingli Wu

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18 Energy Consumption and Carbon Emission of Residential Areas in Changsha Based on Local Climate Zone Scheme . . . . . . . . . 217 Yaping Chen, Hui Ding, Yinze Hu, and Yanyun Feng 19 Study on the Regulation in Countering the Impacts of Climate Change on Water Resource . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229 Junming Gong, Wei Wu, and Chenyu Lin 20 Research on the Impact of Sediment Dredging Activities on the Lingding Bay of Pearl River Estuary, China . . . . . . . . . . . . . . . 241 Yao Xiaowei, Li Wendan, Xie Hualiang, and Li Huaiyuan 21 Distribution Characteristics of Seabed Sediment in Anpu Bay of Guangdong Province, China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253 Xiaowei Yao, Hualiang Xie, Huaiyuan Li, and Zhiyuan Han 22 Evaluation of Urban Livability—A Case Study of Kunming City, China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263 Junmei Li, Qing Hui, Runqiu Fei, Guoqi Qian, Jinyu Liu, Ruixue He, and Jing Zhou 23 Water Level Monitoring Sensor Based on Iontronic Piezo-Capacitance Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279 Changbao Xu, Xiaobo Pu, Jiahao Fang, Tingting Yang, and Mingyong Xin 24 Research on the Implementation Path of Landscape Dispatch of Irrigated Reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 Bin Liu and Huajian Fang 25 An Innovative Photocatalyst Composite of TiO2 /Graphite to Degrade the Dye Wastewater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307 Chao-Lang Kao, Ting-Jia Chen, and Shan-Yi Shen 26 Simulation of Sediment Transport in Coastal Systems, Taking into Account the Heterogeneous Composition of the Soil in a Region of Complex Shape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317 Valentina V. Sidoryakina 27 Urban Water Operational Robustness Failure Preliminary Study: Step Forward Solution to Resilience Improvement of Future Sustainable City . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329 Jian Zang 28 Reason Analysis and Countermeasure Research on Emulsified Oil of Zhen 2 Lian . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341 Lei Haoran

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29 Transit Mental and Their Complexes Catalyzed Oxidative Degradation of Guar Gum by H2 O2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 357 Gao Rongsheng, Cao Yiping, Zhang Xianghui, Liu Qi, Liu Yifan, and Wu Lanbing 30 Prediction of Eco-Economic-Social Coordinated Development Based on Artificial Neural Network (ANN) Model: A Case Study of Qinling Area of Giant Panda National Park . . . . . . . . . . . . . 367 Yan Gao, Zongxing Li, and Qi Feng 31 Enhancement of Natural Iron-Bearing Mineral on Microbial Reduction of Hexavalent Chromium . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377 Xinglan Cui, Hongxia Li, Peng Zheng, Lei Wang, and Xinyue Shi

Chapter 1

3D Continuous and Discrete Models of Multicomponent Suspended Transport for Coastal Marine Systems: Research and Application Valentina V. Sidoryakina , Alexander I. Sukhinov , Alexander E. Chistyakov , and Inna Yu. Kuznetsova

Abstract Currently, there is increasing interest in research of suspended matter transfer processes. Such interest can be explained by the high applied value of these studies, since the implementation of many engineering projects (for example, laying of deep-water pipelines, construction of drilling platforms, dredging, bridge construction) requires an assessment of the feasibility of the project, the risks associated with natural emergencies, and the impact of planned projects on the environmental situation in the water area. Therefore, it is required to develop calculation models that characterize the transport of suspended matter, considering the granulometric composition of the suspension, the hydraulic fineness of the suspension fractions and the analysis of the processes of transport and sedimentation of particles in the fluid flow. In this article, the authors consider the problem of numerical modeling of the transfer of multicomponent suspended matter in relation to coastal marine systems using the Sea of Azov as an example. A software package has been developed to solve the considered problem, based on which numerical experiments have been carried out to simulate the transport of suspended matter during soil dumping during dredging. The results of the computational experiments demonstrated the stability, reliability, and practical significance of the developed model. The study was financially supported by the Russian Science Foundation (Project No. 22-11-00295, https://rscf.ru/en/project/22-11-00295/). V. V. Sidoryakina · A. I. Sukhinov (B) · A. E. Chistyakov Don State Technical University, Rostov-On-Don, Russia e-mail: [email protected] V. V. Sidoryakina e-mail: [email protected] A. E. Chistyakov e-mail: [email protected] I. Yu. Kuznetsova Southern Federal University, Rostov-On-Don, Russia e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_1

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Keywords Coastal marine systems · Spatial-three-dimensional model · Transport of multifractional suspensions · Mutual transformations of fractions · Diffusion-convection-deposition processes

1.1 Introduction The quantitative determination of the concentration of suspended solids (suspensions) and the study of their dynamics are important for understanding many of the processes that determine the natural characteristics and condition of marine systems. In this regard, coastal systems are the most vulnerable and sensitive to change. In coastal systems, the processes of transport of suspended matter are characterized by high concentration, relative fineness of particles, coherence and tendency to flocculation of particles, saturation with mineral, organic, chemical and pollutants. Wind force, freshwater runoff, coastal erosion, rainfall, dredging, and fishing have a significant impact on the intensity of these processes (Yan et al. 2020; Battisacco et al. 2016; Liu et al. 2015; Cao et al. 2021). Comprehensive studies are required for a deep understanding of the processes of suspended matter transport. An important role in the development of ideas about these processes at different times was played by the works of Soviet and Russian scientists, including Longinov V.V., Zenkovich V.P., Kosyan R.D., Antsyferov S.M., Pykhov N.V., Pavlidis Yu.A., Aibulatov N.A., Aksenov A.A., Leontiev I.O., Nevessky E.N., Debolsky V.K., Safyanov G.A. and many others. They are joined by the works of foreign specialists Nielsen P., Horikawa K., Bruun P., Deigaart R., Hanes D.M., Huntley D.H., Vincent C.E., Hayes M.O., Homma M., Horikawa K., Clark T.L., Kana T.W., Kantardgi I.G. and others. The accumulation of new knowledge and experimental data encourages us to obtain new results on the problem we are interested in. In modern research, there is a clear tendency to build mathematical models of suspended matter transport processes based on non-stationary equations of convection–diffusion-sedimentation (transfer) (Serra et al. 2022; Haddadchi and Hicks 2021; Jirka 2001). In this article, the authors present a spatial-three-dimensional model of suspension transport, considering the process of movement of the aquatic environment, the multicomponent composition of the suspension and the mutual transition (transformation) of particles with different hydraulic fineness, the process of sedimentation of suspension, etc. In addition, during the discretization of the constructed continuous initial-boundary value problem, the transformation of the right-hand sides with “lag” is performed. This is done to simplify the subsequent numerical implementation and reduce the computational effort of the diffusion-convection equations because when considering the initial boundary value problem for one fraction, the concentration functions (on the right side of the equation) of other fractions are determined on the previous time layer. Note that in the case of three or more fractions of the suspended matter, this approach makes it possible to organize an independent (parallel) calculation of the concentration of each fraction at each time step. The paper also presents

1 3D Continuous and Discrete Models of Multicomponent Suspended …

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the results of numerical experiments. For testing, we used data on the Sea of Azov, obtained by the authors during the expeditions.

1.2 Statement of the Problem of Transport of Multicomponent Suspensions Consider the rectangular Cartesian coordinate system O x yz, where the axes O x and O y pass along the undisturbed water surface and are directed to the north and east, respectively, the axis Oz is directed downward. Let G ⊂ R3 is the area in which the process occurs, and which is a parallelepiped G = 0 < x < L x , 0 < y < L y , 0 < z ≤ L z . Denote the lower base of the parallelepiped is b , upper base is  f , side surface is l . We consider that in the area G there are R types of suspended particles, which at the point (x, y, z) and at the time t have concentration cr = cr (x, y, z, t); t is a time variable. Let there be a suspension of a multifractional composition in the region G. . To simplify the calculations, we will consider a suspension consisting of three fractions (the problem statement for the general case is presented, for example, in Sukhinov et al. 2020a, b). The restriction imposed on the number of fractions does not affect the general idea of obtaining the result presented in the work. Mathematical model describing the transport of multifractional suspension can be represented as a system of equations for each individual fraction of the suspension. In this case, the equation for a separate fraction will have the following form:         ∂cr ∂cr ∂cr ∂cr ∂cr ∂cr ∂cr ∂ ∂ ∂ +u +v + w + wgr = μhr + μhr + μvr + Fr . ∂t ∂x ∂y ∂z ∂x ∂x ∂y ∂y ∂z ∂z

(1.1) Here and further in the text r = 1, 2, 3. Equations (1.1) use the following notation: cr = cr (x, y, z, t) is the concentration of suspended particles of type r at the point (x, y, z) and at the time t; u, v, w are components of the velocity vector V of the aquatic environment; wgr is a hydraulic particle size of particles of the type r ; μhr , μνr are the coefficients of horizontal and vertical turbulent diffusion of particles of the type r , respectively. The functions Fr have the form: F1 = (α2 c2 − β1 c1 ) + γ1 c1 , F2 = (β1 c1 − α2 c2 ) + (α3 c3 − β2 c2 ) + γ2 c2 , F3 = (β2 c2 − α3 c3 ) + γ3 c3 ,

(1.2)

where αr , βr are the coefficients determining the intensity of transformation of particle of the type r into type (r − 1) and type (r + 1), respectively, αr ≥ 0, βr ≥ 0; γr is the power of the external particle source of the type r . The initial and boundary conditions for Eqs. (1.1) are formulated as follows:

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cr (x, y, z, 0) = cr 0 (x, y, z), (x, y, z) ∈ G; l :

cr = cr , cr = const, if u n < 0;

∂cr = 0, if u n ≥ 0 → ∂− n

(1.3) (1.4)

→ n to the where u n is the projection of the velocity vector onto the outer normal −  boundary, cr is known concentration values; f :

∂cr = 0; b : ∂z

wgr ∂cr cr . =− ∂z μνr

(1.5)

1.3 Transformation with “Lag” of the Problem of Transport of Multicomponent Suspensions For the transformation with “lag” of problem (1.1–1.5) with initial and boundary conditions, we construct a uniform grid ωτ = {tn = nτ, n = 1, . . . , N ; N τ ≡ T } with a step τ on the time interval 0 ≤ t ≤ T . On the time grid ωτ for the original continuous initial-boundary value problem (1.1–1.5), we perform a transformation with a “lag”, so that the functions of concentrations of suspensions included in the right-hand sides of the Eqs. (1.1) are determined on the previous time layer. At each time step of the number n = 1, 2, . . . , N , tn−1 < t ≤ tn the transformed Eqs. (1.1) are considered, the solutions of which are the functions c˜rn , n = 1, 2, . . . , N + 1:  ∂ c˜rn ∂ c˜rn ∂ c˜n ∂ c˜n  + u n r + v n r + w n + wgr ∂t ∂x ∂y ∂z       ∂ ∂ ∂ c˜rn ∂ c˜rn ∂ c˜rn ∂ μhr + μhr + μvr + F˜rn , (1.6) = ∂x ∂x ∂y ∂y ∂z ∂z   F˜1n = α2 c˜2n−1 (x, y, z, tn−1 ) − β1 c˜1n + γ1n c˜1n ,     F˜2n = β1 c˜1n−1 (x, y, z, tn−1 ) − α2 c˜2n + α3 c˜3n−1 (x, y, z, tn−1 ) − β2 c˜2n + γ2n c˜2n ,   F˜3n = β2 c˜2n−1 (x, y, z, tn−1 ) − α3 c˜3n + γ3n c˜3n , (1.7) where c˜rn−1 (x, y, z, tn−1 ) is the final value of the concentration of suspended particles of the type r , calculated on the previous time layer tn−2 < t ≤ tn−1 , n = 2, . . . , N . We add to Eqs. (1.6) the initial conditions of the form:     c˜r1 (x, y, z, 0) = cr 0 , c˜rn x, y, z, tn−1 = c˜rn−1 x, y, z, tn−1 , n = 2, . . . , N , (x, y, z) ∈ G;

(1.8)

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as well as boundary conditions similar to conditions (1.3–1.5). For all t, tn−1 < t < tn , n = 1, 2, . . . , N , we have: l :

c˜rn = cr , if u n < 0;

f :

∂ c˜rn = 0; b : ∂z

∂ c˜rn = 0, if u n ≥ 0; → ∂− n wgr n ∂ c˜rn =− c˜ . ∂z μνr r

(1.9) (1.10)

Previously, the authors obtained conditions under which the differences between the solutions of the initial and transformed initial-boundary value problems, with a “lag” in the functions of the right-hand sides on the time grid, tend to zero as the parameter τ tends to zero with a speed O(τ ) in the Hilbert norm L 2 .

1.4 Construction of a Discrete Model of the Problem of Transport of Multicomponent Suspensions Transformed with a “Lag” Further, the symbol “–” above the functions c˜rn and F˜rn will mean that they belong to the class of grid functions. The function c˜rn is considered as a sufficiently smooth function of continuous variables. The term describing the advective transport of suspended particles in the so-called symmetric form has the form (Samarskii and Vabishchevich 2004):          ∂crn ∂ ucrn ∂ vcrn ∂ w + wgr crn ∂crn  1 ∂crn +v + w + wgr + + + u , 2 ∂x ∂y ∂z ∂x ∂y ∂z (1.11) which allows us to construct a difference advective transfer operator with the skewsymmetry property as a result of discretization. = ωx × In the area G, we construct a connected grid ωh {x ω y × ω z , where ω = : x = i h ; i = 0, 1, ..., N ; N h ≡ L x }, x i i x x x x   ωy = y j : y j = j h x ; j = 0, 1, ..., N y ; N y h y ≡ L y , ωz = {z k : z k = kh x ; k = 0, 1, ..., Nz ; Nz h z ≡ L z }. The set of internal nodes of the grids ωh , ω x , ω y , ω z will be denoted as ωh , ωx , ω y , ωz , respectively. On the space–time grid ωτ h = ωτ × ωh we approximate problems (1.6–1.10) on grids “with a task” at nodes shifted by half the grid step speeds and along the corresponding coordinate direction. Approximations of each of the Eqs. (1.6) in the internal nodes of the grid ωh are obtained on the grids constructed by the methods described in:

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V. V. Sidoryakina et al.  q rn − q rn−1 1  n u (x + 0.5h x , y, z)q rn (x + h x , y, z)− u n (x − 0.5h x , y, z) q rn (x − h x , y, z) + τ 2h x        1  n v x, y + 0.5h y , z q rn x, y + h y , z − v n x, y − 0.5h y , z q rn x, y − h y , z + 2h y    1  n + w (x, y, z + 0.5h z ) + wgr q rn (x, y, z + h z ) − w n (x, y, z − 0.5h z ) + wgr 2h z   1  · q rn (x, y, z − h z ) = 2 μhr (x + 0.5h x , y, z) q rn (x + h x , y, z) − q rn (x, y, z) hx     1  − μhr (x − 0.5h x , y, z) q rn (x, y, z) − q rn (x + h x , y, z) + 2 μhr x, y + 0.5h y , z hy         · q rn x, y + h y , z −q rn (x, y, z) − μhr x, y − 0.5h y , z q rn (x, y, z) − q rn x, y − h y , z   1 + 2 (μvr (x, y, z + 0.5h z ) q rn (x, y, z + h z ) − q rn (x, y, z) − μvr (x, y, z − 0.5h z ) hz   n (1.12) · q rn (x, y, z) − q rn (x, y, z − h z ) + F r (x, y, z), (x, y, z) ∈ ωh .

In Eqs. (1.12), the approximation of the terms describing the source functions has the form:   n F 1 = α2 c˜2n−1 (x, y, z, tn−1 ) + −β1 + γ1n (x, y, z) q n1 (x, y, z),

(1.13)

  n F 2 = β1 c˜1n−1 (x, y, z, tn−1 ) + −α2 − β2 + γ2n (x, y, z) q n2 (x, y, z),

(1.14)

  n F 3 = β2 c˜2n−1 (x, y, z, tn−1 ) + −α3 + γ3n (x, y, z) q n3 (x, y, z), (x, y, z) ∈ ωh . (1.15) It is necessary to add to the difference Eqs. (1.12) the initial conditions of the form (1.8) for (x, y, z) ∈ ωh , as well as approximation of boundary conditions. To set boundary conditions of the it is convenient to introduce an extended grid form (1.9), (1.10),  ω∗ = xi , y j , z k , i = −1, 0, . . . , N x + 1; j = −1, 0, . . . , N y + 1; k = −1, 0, . . . , Nk + 1; xi = i h x ; y j

 = j h j ; z k = kh k ; N x h x = L x ; N y h y = L y ; Nz h z = L z . For the grid ω∗ the grid ωh is internal. We will assume that q rn (x, y, z) = 0, if (x, y, z) ∈ ω∗ \ωh . In addition, we will assume that the values of the components u, v, w of the velocity vector at the grid nodes ω∗ \ωh with fractional n n index  values are known,  for example, u (−0.5h x , y, z), u (L x + 0.5h x , y, z), n n v x, −0.5h y , z , v x, L y + 0.5h y , z etc. For those grid nodes ω∗ \ωh , which are outside the reservoir, the values of the components u, v, w are assumed to be zero. Approximation of boundary conditions for a surface l on which the boundary nodes of the grid ω∗ are located as follows:

1 3D Continuous and Discrete Models of Multicomponent Suspended …



7

q rn(0,y,z) = 0, if u n (0.5h x , y, z) + u n (−0.5h x , y, z) > 0,

q rn (L x , y, z) = 0, if u n (L x − 0.5h x , y, z) + u n (L x + 0.5h x , y, z) < 0; (1.16)

n     q r (x, 0, z) = 0, if v n x, 0.5h y , z + v n x, −0.5h y , z > 0,       q rn x, L y , z = 0, if v n x, L y − 0.5h y , z + v n x, L y + 0.5h y , z < 0. (1.17) For the surface l under the conditions u n (0.5h x , y, z) + u n (−0.5h x , y, z) > 0, u n (L x − 0.5h x , y, z) + u n (L x + 0.5h x , y, z) < 0,     v n x, 0.5h y , z + v n x, −0.5h y , z > 0,     v n x, L y − 0.5h y , z + v n x, L y + 0.5h y , z < 0,

(1.18)

the boundary conditions are written in the Neumann form. Let us give approximations of the boundary conditions for the convective and diffusion transport operators: – for the convective transfer operator:     1 n C x q rn x=0 ≡ q (h x , y, z) u n (0.5h x , y, z) −u n (−0.5h x , y, z) , 2h x r     1 n C x q rn x=L ≡ q (L x − h x , y, z) u n (L x + 0.5h x , y, z) −u n (L x − 0.5h x , y, z) , x 2h x r        1 n C y q rn  y=0 ≡ q x, h y , z v n x, 0.5h y , z −v n x, −0.5h y , z , 2h y r        1 n C y q rn  y=L ≡ q x, L y − h y , z v n x, L y + 0.5h y , z −v n x, L y − 0.5h y , z , y 2h y r     1 n q (x, y, h z ) w n (x, y, 0.5h z ) −w n (x, y, −0.5h z ) + 2wgr , C z q rn z=0 ≡ 2h z r       wgr 1  n w (x, y, L z + 0.5h z ) + wgr q rn (x, y, L z − h z ) − 2 C z q rn z=L ≡ h z q rn (x, y, L z ) z 2h z μνr    − w n (x, y, L z − 0.5h z ) + wgr q rn (x, y, L z − h z ) ;

– for the diffusion transfer operator:   Dx q rn x=0

  Dx q rn x=L

≡

  1  (μhr (0.5h x , y, z) + μhr (−0.5h x , y, z)) q rn (h x , y, z) − q rn (0, y, z) , h 2x

≡

  1  (μhr (L x + 0.5h x , y, z) + μhr (L x − 0.5h x , y, z)) q rn (L x − h x , y, z) − q rn (L x , y, z) , h 2x

≡

       1  μhr x, 0.5h y , z + μhr x, −0.5h y , z q rn x, h y , z − q rn (x, 0, z) , h 2y

x

  D y q rn  y=0

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  D y q rn  y=L

y

≡

         1  μhr x, L y + 0.5h y , z + μhr x, L y − 0.5h y , z q rn x, L y − h y , z − q rn x, L y , z , h 2y

    1  Dz q rn z=0 ≡ 2 μvr (x, y, 0, 5h z ) q rn (x, y, h z ) − q rn (x, y, 0) , hz   1  Dz q rn z=L ≡ 2 (μvr (x, y, L z + 0, 5h z ) + μvr (x, y, L z − 0, 5h z ))q rn (x, y, L z − h z ) z hz    wgr h z μvr (x, y, L z + 0, 5h z ) + μvr (x, y, L z − 0, 5h z ) q rn (x, y, L z ) . − 2 μνr

Note that when approximating the diffusion transfer operators, we considered that there is no turbulent diffusion on the free undisturbed surface of the reservoir and therefore μvr (x, y, −0.5h z ) ≡ 0. With regard to the values of the components u, v, w of the   velocity vector  u n (−0.5h x , y, z), u n (L x + 0.5h x , y, z), v n x, −0.5h y , z , v n x, L y + 0.5h y , z , as well as coefficients μhr (−0.5h x , y, z), μhr (L x + 0.5h x , y, z), μhr x, −0.5h y , z ,   μhr x, L y + 0.5h y , z it is assumed that in the expansion of the area G in horizontal directions (on the grid ω∗ ) there is an aquatic environment and these values can be determined in the hydrodynamic block of the combined model “hydrodynamics—transport of suspended matter”.

1.5 Numerical Experiment A software package has been developed to solve the considered problem of transport of multifractional suspension (1.1–1.5). The software package is written in C++ . This software product allows to simulate both individual processes occurring in the aquatic environment and to implement a complex model “hydrodynamics—transport of a multi-fraction suspension”. Let us give an example of the operation of the software package on the problem of transporting a three-component suspension when modeling the process of soil dumping during dredging. For a preliminary assessment of the quality of the constructed model, numerical experiments were carried out in a model area extended along one of the spatial directions, which approximately corresponds to the ratio of the sizes of the Sea of Azov, but without considering the complex geometry of the boundaries of the calculation area. Parameters of the calculated area: length (L x ) is 1 km; width (L y ) is 600 m; depth (L z ) is 10 m. The parameters of the calculated grid: h x = 10 m, h y = 10 m, h z = 1 m, T = 2 hours, τ = 5 s.

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Fig. 1.1 Concentration fields of fraction A of suspension 2 h after unloading: a in the water column; b in bottom sediments

Input parameters of the model: average sedimentation (settlement) rate of suspensions (according to Stokes) wg = 2.042 mm/s; distance from the unloading point to the bottom of the reservoir is 5.5 m; flow velocity is 0.075 m/s (the flow is directed from left to right). For fraction A: wga = 2.4 mm/s, percentage of fraction in dusty particles is 22%. For fraction B: wgb = 1.775 mm/s, the percentage is 48%. For fraction C: wgc = 0.833 mm/s, the percentage is 30%. Figures 1.1, 1.2, 1.3 show the results of modeling the transport of a threecomponent suspension for each of the three fractions separately. The horizontal axis in Figs. 1.1–1.3 is directed along the current and in the place of the maximum concentration of suspended particles (in the y = 300 m). Figures 1.1a, 1.2a and 1.3a show the concentration fields of three suspended matter fractions in the water column. Figures 1.1b, 1.2b and 1.3b show the concentration of the corresponding suspension fraction in bottom sediments. The figures show that lighter fractions of suspension are carried away by the flow for long distances from the unloading point. The heavier fraction A lies deeper in the sediment than the lighter fractions B and C.

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Fig. 1.2 Concentration fields of fraction B of suspension 2 h after unloading: a in the water column; b in bottom sediments

Fig. 1.3 Concentration fields of fraction C of suspension 2 h after unloading: a in the water column; b in bottom sediments

1.6 Conclusion This paper presents the results of research and modeling of the dynamics of the transfer processes of a multicomponent suspension. A discrete model is obtained by approximating the corresponding continuous model using a “lag” transformation. Particular attention is paid to the creation of efficient software for computational experiments. The conducted numerical experiments allow us to simulate the process of distribution and settling of suspended matter on the bottom, as well as to study the influence of these processes on the change in the relief and composition of the bottom of the considered water area.

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References Battisacco E, Franca MJ, Schleiss AJ (2016) Sediment replenishment: influence of the geometrical configuration on the morphological evolution of channel-bed. Wat Resour Res 52(11):8879– 8894. https://doi.org/10.1002/2016WR019157 Cao L, Liu S, Wang S, Cheng Q, Fryar AE, Zhang Z, Yue F, Peng T (2021) Factors controlling discharge-suspended sediment hysteresis in karst basins, southwest China: implications for sediment management. J Hydrol 594:125792. https://doi.org/10.1016/j.jhydrol.2020.125792 Haddadchi A, Hicks M (2021) Interpreting event-based suspended sediment concentration and flow hysteresis patterns. J Soils Sed 21(1):592–612. https://doi.org/10.1007/s11368-020-02777-y Jirka GH (2001) Large scale flow structures and mixing processes in shallow flows. J Hydr Res 39(6):567–573. https://doi.org/10.1080/00221686.2001.9628285 Liu X, Qi S, Huang Y, Chen Y, Du P (2015) Predictive modeling in sediment transportation across multiple spatial scales in the Jialing River Basin of China. Int J Sedim Res 30(3):250–255. https://doi.org/10.1016/j.ijsrc.2015.03.013 Samarskii AA, Vabishchevich PN (2004) Numerical methods for solving convection-diffusion problems. M.: Editorial Serra T, Soler M, Barcelona A, Colomer J (2022) Suspended sediment transport and deposition in sediment-replenished artificial floods in Mediterranean rivers. J Hydrol 609:127756. https://doi. org/10.1016/j.jhydrol.2022.127756 Sukhinov AI, Chistyakov AE, Protsenko EA, Sidoryakina VV, Protsenko SV (2020a) Parallel algorithms for solving the problem of coastal bottom relief dynamics. In: Numerical methods and programming (Vychislitel’nye Metody i Programmirovanie), vol 21(3). 196–206 Sukhinov AI, Sukhinov AA, Sidoryakina VV (2020b) Uniqueness of solving the problem of transport and sedimentation of multicomponent suspensions in coastal systems structures. IOP Conf Ser: J Phys: Conf Ser 1479(1):012081 Yan H, Vosswinkel N, Ebbert S et al (2020) Numerical investigation of particles’ transport, deposition and resuspension under unsteady conditions in constructed stormwater ponds. Environ Sci Eur 32:76. https://doi.org/10.1186/s12302-020-00349-y

Chapter 2

Direct and Indirect Ultrasonic-Assisted Preparation of Calcium Alginate Monolithic Pellets for the Removal of Methylene Blue from Aqueous Solution Jia Jun Isaac Yong, Voon-Loong Wong , Swee Pin Yeap , Siew Shee Lim , and Nurul Husna Mohd Yusoff

Abstract Biosorption offers cost advantages over conventional treatment methods due to technical and financial constraints. In present paper, calcium alginate (CaAlg) monolithic pellets are investigated as biosorbents for the removal of methylene blue (MB) from aqueous solution in a batch mode. Direct and indirect ultrasonication was employed for the preparation of porous CaAlg pellets to enhance their removal efficiency (R%) and adsorption capacity (qe ). In preliminary stage, the effectiveness of pure CaAlg pellets were evaluated based on different concentrations of sodium alginate (SA) (1wt%, 2wt%, and 3wt%). The synthesis of CaAlg pellets from 3wt% sodium alginate exhibited the highest adsorption capacity of 1.302 mg/g. Surface characterizations were studied to examine the morphology of the pure and ultrasonicated 3wt% CaAlg monolithic pellets using scanning electron microscopy (SEM) before and after adsorption. SEM images revealed that the surface of ultrasonicassisted CaAlg monolithic pellets exhibits pores and fissures. Meanwhile, the experimental results indicated that the R% and qe of CaAlg pellets arranged in a descending order of direct ultrasonicated CaAlg (88.13%, 2.058 mg/g) > indirect ultrasonicated CaAlg (78.61%, 1.657 mg/g) > pure CaAlg (57.06%, 1.302 mg/g) at a batch adsorption condition of 250 rpm at 30 °C for 6 h. These pellets performed at least 21% J. J. I. Yong · V.-L. Wong (B) School of Engineering ang Physical Sciences, Heriot-Watt University Malaysia Campus, 62200 Wilayah Persekutuan Putrajaya, Malaysia e-mail: [email protected] S. P. Yeap Department of Chemical and Petroleum Engineering, Faculty of Engineering, Technology and Built Environment, UCSI University, Kuala Lumpur, Malaysia UCSI-Cheras Low Carbon Innovation Hub Research Consortium, Kuala Lumpur, Malaysia S. S. Lim · N. H. M. Yusoff Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Malaysia © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_2

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better for MB removal than those synthesized in the absence of ultrasonic waves. Thus, the adoption of ultrasonication showed a promising potential for the synthesis of CaAlg monolithic pellets with improved adsorption properties to remove organic pollutants from dye wastewaters. Keywords Ultrasonication bath · Homogeniser · Calcium alginate · Methylene blue · Biosorption

2.1 Research Background Most commercial synthetic dye is found in the textile industry, which generates more than 800,000 tonnes per year. Annually, 5–10% of various dyes were discharged and released into natural waters as waste due to the improper handling. From 2022 to 2030, the global textile market is projected to expand at a CAGR of 4.0%, initiated with a size of USD 993.6 billion in 2021 (2022). Over the course of the projected period, rising demand for apparels from the fashion industry and the growing ecommerce platforms are anticipated to drive the market growth. Due to the increasing demand in the textile industry and the growing production of synthetic dye, harmful chemicals in synthetic dyes could pose a serious threat to the ecosystem if the harmful effluents are not handled adequately (Tay et al. 2021). Despite having well-established technologies for dye removals, such as biological, physical, and chemical treatments, most of the technologies are still ineffective in treating dye wastewater as each treatment has its own limitation (Rai et al. 2005). The main drawback of the conventional biological treatments is the ineffectiveness to remove hazardous components in synthetic dyes although being widely used in most countries due to their simplicity and affordability. Besides, the high energy requirements and high operating cost of chemical treatments such as UV radiation (Abrile et al. 2020), ozonation (Venkatesh et al. 2017) and electrochemical destructions (Riera-Torres and Gutiérrez 2010) are also the main disadvantage. For physical treatments such as ion exchange (Hassan and Carr 2018), coagulation and flocculation (Moghaddam et al. 2010) as well as membrane filtration (Katheresan et al. 2018), significant amounts of harmful sludge and foul are produced and would lead to high maintenance cost and complexity. Biosorption has many advantages over other conventional treatment methods, including the ability to remove both organic and inorganic pollutants effectively, simplicity and low cost of operation. An effective adsorbent should be chemically and mechanically stable, have large surface area and a sizable number of functional groups that increase the selectivity and adsorption capacity. Despite sodium alginate (NaAgl) has a low heat resistance and low mechanical strength, it is shown to be a natural efficient adsorbent due to the strong adsorption affinity provided by the hydroxyl and carboxyl groups (Nasrullah et al. 2018). In addition, the major advantage of NaAgl over other adsorbents is their liquid-gel behaviour in aqueous

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solutions (Asadi et al. 2018). This is resulted from the different divalent cations, typically calcium, replacing sodium ions from the guluronic acid residues. A 3D network is thus formed when a divalent cation is bound to the α-L-guluronic block. Due to their accessibility, hydrophilicity, nontoxicity and biocompatibility, calcium alginate (CaAlg) hydrogels can potentially be used as sorbents (Santos 2017). Considering the advantages listed above, CaAlg adsorption could be the suitable option for dye removal. With the conventional technologies being constrained due to the technical and financial reasons, an ultrasonic dispersion method on the synthesis of CaAgl monolithic pellets to remove cationic methylene blue (MB) was employed. In present work, two different techniques: indirect sonication bath on CaAlg monolithic pellets and direct ultrasonic probe on the native NaAgl solution were examined. This work aims to quantify the adsorption performance of the CaAgl monolithic pellets as well as to explain the fundamental phenomenon of improved adsorption science for the removal of cationic MB. The effect of ultrasonication bath and ultrasonic homogenizer on the CaAgl monolithic pellets to remove MB were also compared. Consequently, this study has filled the research gap on MB dye adsorption via ultrasonic assisted-CaAgl monolithic pellets that has not been fully discussed in the past literatures.

2.2 Methodology 2.2.1 Preparation of CaAgl Pellets via Direct and Indirect Ultrasonication By dissolving 6 g of sodium alginate (NaAgl) powder (Sigma Aldrich, Germany) with 200 ml of distilled water, a 3 wt% NaAgl solution was prepared. Likewise, 1 wt% and 2wt% of NaAgl solution concentrations were also prepared accordingly. 20 g of calcium chloride (CaCl2 ) powder (HmBG Chemical, Malaysia) was dissolved into 1 L of distilled water to prepare 2 wt% of CaCl2 concentration. 2 wt% of CaCl2 solution was used as cross-linking agent for all three NaAgl concentrations. To prepare the CaAgl monolithic pellets via indirect ultrasonication (see Fig. 2.1a), a dialysis tube was filled with 50 ml of the 1 wt%, 2 wt%, and 3 wt% of NaAgl solution with both ends securely clipped with a clip. The tube was submerged into a beaker containing 500 ml of CaCl2 solution. The tube was removed from the beaker after 24 h at room temperature (25 °C). Both clips at the end were opened to remove the solid cylindrical CaAlg disc. The CaAlg gel was sliced with a knife after being washed with distilled water. The pellets were then produced from the slices using a hole plunger. The pellets were immersed in the beaker filled with distilled water until the pH value reaches 7 indicated by a pH meter. Next, the CaAlg monolithic pellets were submerged into conical flasks containing 100 ml of distilled water and placed into an ultrasonication bath (Elmasonic EASY 30H, Germany) at main frequency 50/60 Hz (ultrasonic frequency: 37 kHz) with temperature ranging from 30 to 60 °C) for 2 h.

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Fig. 2.1 Preparation of CaAlg Monolithic Pellets via a indirect and b direct ultrasonication

For direct ultrasonication as shown in Fig. 2.1b, an ultrasonic homogenizer (T25 ULTRA-TURRAX, IKA, Germany) was used. The homogenizer tip was placed into the beaker filled with 3 wt% NaAgl solution and the solution were homogenized at high-speed circumferential force of homogenisation (3000 rpm, 9000 rpm, and 15,000 rpm) for 5 min accordingly. The NaAgl solution was then transferred into the dialysis tube and securely clipped at both ends. A dialysis tube was filled with 50 ml of the NaAgl solution with both ends securely clipped with a clip. The tube was submerged into a beaker containing 500 ml of CaCl2 solution for 24 h of crosslinking at room temperature (25 °C) and the CaAlg monolithic pellets were produced from the CaAlg slices using a hole plunger. The CaAlg pellets were vigorously rinsed with distilled water until reached pH 7.

2.2.2 Preparation of MB Adsorbate Methylene blue (MB), a cationic dye was selected as the key adsorbates in this study. MB powder was sourced from Systerm, Malaysia. For MB, stock solutions with a range of concentrations (20 to 100 ppm) were prepared and diluted with

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distilled water. All MB dye solution was initially calibrated for concentration in terms of absorbance units. The absorbance value in respect to dye concentration was measured using a UV/Vis spectrophotometer (HACH DR6000, USA) at the maximum absorbance wavelength (λmax = 663 nm).

2.2.3 Surface Characterisation Studies The surface morphology of the pure and ultrasonicated CaAlg monolithic pellets was examined using scanning electron microscope (SEM) (JSM-IT100, Japan) before and after MB adsorption at magnification of × 50 to × 200. The accelerating voltage of SEM was set at 5 kV and operated under high vacuum.

2.2.4 Batch Adsorption Studies Batch adsorption experiments were carried out in conical flasks by using an average mass of 0.47 g CaAlg pellets in 50 ml of MB solution with a concentration of 20 ppm. The mixture in the conical flasks was stirred in an incubator shaker at a constant speed of 250 rpm and room temperature (25 °C). The treated working samples were withdrawn from the flasks and the dye concentration was determined using UV–Vis spectrophotometer (HACH DR6000, USA) at every 1-h interval. Preliminary experiment was carried out by comparing the adsorption capacity (qe ) and MB removal efficiencies among the pure CaAlg monolithic pellets with various NaAlg concentration ranged from 1 to 3 wt%. The pure CaAlg with the highest adsorption capacity was used as adsorbent for the sorption experiments subsequently. Next, the adsorption experiment was carried out by comparing the adsorption capacity (qe ) and MB removal efficiencies (R%) between the selected pure CaAlg and ultrasonicated CaAlg monolithic pellets. All the experiments were conducted in triplicate with a control and the average value were taken for analysis. Equation (2.1) was used to determine the MB R% of CaAlg monolithic pellets: Removal Efficiency (R%) =

(Ci − C f ) × 100% Ci

(2.1)

where Ci denotes the initial MB concentration (mg/L) and Cf is the final MB concentration after 6 h (mg/L). Equation (2.2) was used for the determination of adsorption capacity of CaAlg pellets: Adsorption capacity(qe ) =

(Ci − Ct )V m

(2.2)

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where qe is the adsorbed dye quantity per gram of CaAlg pellets at any time (mg/g), Ci and Ct are initial and MB concentrations at time t in the solution (mg/L).

2.3 Results and Discussion 2.3.1 Scanning Electron Microscope (SEM) Analysis Figure 2.2 illustrates the Scanning electron microscopy (SEM) images of pure CaAlg pellets, CaAlg pellets with ultrasonication bath, CaAlg pellets with ultrasonic homogenizer before the adsorption of MB solution. The SEM image in Fig. 2.2a revealed that the surface of pure CaAlg pellets was smooth and free of pores and fissures. On the other hand, the SEM images with indirect and direct ultrasound treatments, shown in Fig. 2.2b and f, indicated a significant impact on the structure of pellets. Notably, the surface of CaAlg pellets was influenced differently and not altered uniformly by direct ultrasound treatment, as seen in Fig. 2.2e. Specifically, the surface of the pellets in Fig. 2.2e remained almost smooth under the effect of ultrasonication, while other samples became more porous with increased pores and irregular surfaces. These findings were in good agreement with the investigations from Jamalabadi et al. where the direct ultrasonication treatment provided different outcomes on the surface of absorbents (Jamalabadi et al. 2019). The visible pores and fissures on the surface of the pellets were attributed to the effect of ultrasound, as reported by Hu et al. (2015). The study further demonstrated that ultrasound-induced the emergence and collapse of bubbles, leading to high-pressure gradients and high local velocities that caused the alteration of the chains of the polymer and surface damages of the pellets, as previously reported by Yang et al. (2019).

2.3.2 Indirect Ultrasonication on CaAlg Pellets’ Adsorption Performance To investigate its impact on MB dye adsorption, weight percentages of 1–3 wt% of CaAlg pellets were tested while other parameters including the cross-linking duration, ultrasonication time and temperature were left constant. The adsorption experiments were conducted using 50 ml of 20 ppm MB dye solution in an incubator shaker with 250 rpm agitation at room temperature. Figure 2.3a and b demonstrate that the ultrasonicated and pure 3 wt% CaAlg pellets have the maximum removal efficiency, at 74.06% and 72.85% respectively. According to Heybet et al., the enhanced removal efficiency is the result of an increase in the number of adsorbate molecules occupying the unoccupied active sites at each increasing adsorbent weight percentage (Heybet et al. 2021). In order to attain the highest adsorption capacity and removal efficiency, the weight percentage of the pellets was selected to be 3 wt%.

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Fig. 2.2 SEM images of CaAlg monolithic pellets. a pure pellets; b indirect ultrasonication, 2 h 50/60 Hz 30 °C; c indirect ultrasonication, 2 h 50/60 Hz 45 °C; d indirect ultrasonication, 2 h 50/ 60 Hz 60 °C; e direct ultrasonication, 3000 rpm; f direct ultrasonication, 9000 rpm

The R% and qe of MB dye solution was assessed using pure CaAlg pellets and ultrasonicated treated CaAlg pellets. Figure 2.3c and d shows that the ultrasonicated 3 wt% CaAlg pellets was evidently found to have the highest removal efficiency (78.61%, 1.657 mg/g). In particular, the ultrasonicated CaAlg pellets had higher removal efficiency com-pared to the pure CaAlg pellets for every hour interval. The removal efficiency of the ultrasonicated CaAlg pellets is improved by the acoustic cavitation phenomena caused by the ultrasonic irradiation. Roosta et al. mentioned that the pres-sure waves that induce micrometrical bubbles to from, expand and implode through liquid increases the mass transfer rate while weakening the affinities between adsorb-ate and adsorbent (Roosta et al. 2014). Roosta et al. further reported that the acoustic streaming induced by the sonic wave can convert sound to kinetic

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Fig. 2.3 The effect of NaAlg weight percentage on the R% of a Pure CaAlg monolithic pellets and b ultrasonicated CaAlg Pellets (T: 55 °C; t (ultrasonication): 1 h; t (cross-linking): 48 h; F:50/ 60 Hz) and the effect of ultrasonication on the (b) R% and c qe of ultrasonicated 3 wt% CaAlg and pure 3 wt% CaAlg (T: 25 °C; t (ultrasonication): 1 h; t (cross-linking): 24 h; F: 50/60 Hz)

energy and there-fore producing microscopic turbulence among the interfacial films that surround the solid particles (Roosta et al. 2014). These phenomena accelerate the mass transfer rate at the surface and subsequently increasing the adsorption capacity. Therefore, the adoption of ultra-sonication is proven to increase the removal efficiency of MB dye solution.

2.3.3 Direct Ultrasonication on CaAlg Pellet’s Adsorption Performance In this study, the removal efficiency of CaAlg pellets using different speed of direct ultrasonication was investigated. Figure 2.4 illustrates that the ultrasonication on CaAlg pellets with 9000 rpm showed the highest removal efficiency, achieving a

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rate of 88.13%. In comparison, the removal efficiency was measured at 86.3% for ultrasonication with 3000 rpm and 87.27% for 15,000 rpm. The MB adsorption is dependent on the porosity and shape of the CaAlg pellets. From Fig. 2.5, the CaAlg pellets assisted by the ultrasound homogenizer obtained the highest R% compared to others, achieving 88.13% while the pellets with ultrasonication bath have the removal efficiency of 78.61%. Probe type sonicators provides higher localized intensity of the ultrasonic wave compared to the bath type. Hence, the probe type sonicators can often create more pores on the surface of the pellets which resulted in higher adsorption capacity (Akram et al. 2016). In particular, the ultrasonicated pellets had higher removal efficiency than the pure CaAlg pellets. Dhanalakshmi et al. reported that the cavitational activity increases as the number of collapsing cavities rises along with the localised intensity (Dhanalakshmi and Nagarajan 2011). Hence, indirect ultrasonication treatment on CaAlg pellets enhances the removal efficiency of MB dye solution.

Fig. 2.4 Comparison of R% for direct ultrasonication at different rotor speed (rpm)

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Fig. 2.5 Comparison of R% between pure CaAlg pellets (3 wt%), CaAlg pellets with direct ultrasonication (9000 rpm) and indirect ultrasonication (50/60 Hz)

2.4 Conclusion The present work demonstrates the potential of ultrasonicated CaAlg monolithic pellets as a cost-effective and efficient bio-sorbent for enhanced MB dye removal. Among the different concentrations of NaAlg tested, the synthesis of CaAlg pellets with 3 wt% concentration of NaAlg provides the highest MB R%, achieving adsorption capacity of 1.302 mg/g. The SEM images analysed that the increased porosity on the surface of pellets due to the ultrasonication can increase the R% of the CaAlg pellets. Additionally, the removal of MB dyes can be intensified through the utilization of indirect and direct ultrasonication. The order of the R% of MB dye was found to be direct ultrasonication (88.13%) > indirect ultrasonication (78.61%) > pure CaAlg pellets (57.06%). Consequently, the direct and indirect ultrasonication have both shown promising approaches in the preparation of porous CaAlg monolithic pellets which can lead to the enhancement of the pore diffusion in sorption processes.

References Abrile MG, Fiasconaro ML, Lovato ME (2020) Optimization of reactive blue 19 dye removal using ozone and ozone/UV employing response surface methodology. SN Appl Sci 2(5):995 Akram M, Chowdhury A, Chakrabarti S (2016) Removal of rhodamine B dye from wastewater by ultrasound-assisted Fenton process: a comparison between bath and probe type sonicators. Environ Sci Ind J 12(10):115–120 Asadi S, Eris S, Azizian S (2018) Alginate-based hydrogel beads as a biocompatible and efficient adsorbent for dye removal from aqueous solutions. ACS Omega 3(11):15140–15148 Dhanalakshmi NP, Nagarajan R (2011) Ultrasonic intensification of the chemical degradation of methyl violet: an experimental study. Int J Chem Molecul Eng 5(11):1033–1038

2 Direct and Indirect Ultrasonic-Assisted Preparation of Calcium …

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Global Textile Market Size Report 2022–2030 (2022, October 10). Market Analysis Report. https:// www.grandviewresearch.com/industry-analysis/textile-market Hassan MM, Carr CM (2018) A critical review on recent advancements of the removal of reactive dyes from dyehouse effluent by ion-exchange adsorbents. Chemosphere 209:201–219 Heybet EN, Ugraskan V, Isik B, Yazici O (2021) Adsorption of methylene blue dye on sodium alginate/polypyrrole nanotube composites. Int J Biol Macromol 193:88–99 Hu A, Jiao S, Zheng J, Li L, Fan Y, Chen L, Zhang Z (2015) Ultrasonic frequency effect on corn starch and its cavitation. LWT-Food Sci Technol 60(2):941–947 Jamalabadi M, Saremnezhad S, Bahrami A, Jafari SM (2019) The influence of bath and probe sonication on the physicochemical and microstructural properties of wheat starch. Food Sci Nutr 7(7):2427–2435 Katheresan V, Kansedo J, Lau SY (2018) Efficiency of various recent wastewater dye removal methods: a review. J Environ Chem Eng 6(4):4676–4697 Moghaddam SS, Moghaddam MA, Arami M (2010) Coagulation/flocculation process for dye removal using sludge from water treatment plant: optimization through response surface methodology. J Hazard Mater 175(1–3):651–657 Nasrullah A, Bhat AH, Naeem A, Isa MH, Danish M (2018) High surface area mesoporous activated carbon-alginate beads for efficient removal of methylene blue. Int J Biol Macromol 107:1792– 1799 Rai HS, Bhattacharyya MS, Singh J, Bansal TK, Vats P, Banerjee UC (2005) Removal of dyes from the effluent of textile and dyestuff manufacturing industry: a review of emerging techniques with reference to biological treatment. Crit Rev Environ Sci Technol 35(3):219–238 Riera-Torres M, Gutiérrez MC (2010) Colour removal of three reactive dyes by UV light exposure after electrochemical treatment. Chem Eng J 156(1):114–120 Roosta M, Ghaedi M, Daneshfar A, Sahraei R, Asghari A (2014) Optimization of the ultrasonic assisted removal of methylene blue by gold nanoparticles loaded on activated carbon using experimental design methodology. Ultrason Sonochem 21(1):242–252 dos Santos LL (2017) Natural polymeric biomaterials: processing and properties Tay SY, Wong VL, Lim SS, Teo ILR (2021) Adsorption equilibrium, kinetics and thermodynamics studies of anionic methyl orange dye adsorption using chitosan-calcium chloride gel beads. Chem Eng Commun 208(5):708–726 Venkatesh S, Venkatesh K, Quaff AR (2017) Dye decomposition by combined ozonation and anaerobic treatment: cost effective technology. J Appl Res Technol 15(4):340–345 Yang QY, Lu XX, Chen YZ, Luo ZG, Xiao ZG (2019) Fine structure, crystalline and physicochemical properties of waxy corn starch treated by ultrasound irradiation. Ultrason Sonochem 51:350–358

Chapter 3

Experimental Study on Sludge Depth Drying Under Dual Physical Fields Yuekan Zhang, Mingyuan Xu, Wei Hu, Qingyun Zhang, and Jiangbo Ge

Abstract Sludge drying is a prerequisite for the sludge handling and resources. However, the high moisture content of sludge and difficulties in dewatering are bottlenecks that limit the sludge treatment industry. In this paper, we adopt the sludge cyclone drying method, which based on the dual physical field action of cyclone field and temperature field, and conduct an experimental study on the effect of sludge moisture rate, sludge feed volume, carrier gas temperature, carrier gas flow rate on the sludge cyclone drying performance. The experimental results show that the sludge discharge moisture rate can reach 20% when the sludge moisture rate is 50% and the carrier gas temperature is 80 °C. At a carrier gas temperature of 110 °C, the sludge moisture rate can be reduced to 13.4%. Keywords Sludge drying · Cyclone field · Temperature field · Drying performance

3.1 Introduction Sewage sludge contains harmful substances such as bacteria and viruses, which are very likely to cause secondary pollution of soil, water and air (Swierczek et al. 2018; Ling et al. 2022; Yang et al. 2022). Meanwhile, dry-based sludge contains numerous beneficial elements such as nitrogen, phosphorus, potassium and carbohydrates (Iticescu et al. 2021), which can be recycled and utilised as a renewable resource. Therefore, sludge drying is a prerequisite for the reduction, harmlessness and resourcefulness of sludge. At present, sludge dewatering and drying is mainly based on thermal drying methods (Wu et al. 2020), using different thermal media (hot air, hot steam, hot oil) to achieve the reduction of the moisture rate of sludge by acting directly or indirectly Y. Zhang (B) · M. Xu · W. Hu · Q. Zhang · J. Ge College of Mechanical & Electronic Engineering, Shandong University of Science and Technology, Qingdao 266590, China e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_3

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with the sludge. But high energy consumption has become a key technical bottleneck limiting the sludge treatment industry. Cyclones as multi-phase fluid separation equipment, because of its simple structure, small footprint, and can be suitable for different working conditions, commonly used in coal mines (Xing et al. 2021), oil (Dou et al. 2022) and other solid–liquid separation field. Huang et al. (2017) found that the movement of material in the cyclone includes macroscopic rotation along the cyclone wall and microscopic movement of its own rotation. The macroscopic motion is due to the centrifugal force, the particles with the flow carrier in the cyclone to form the overall rotation; microscopic motion is the particle in the cyclone field by the influence of non-uniform forces, resulting in the particle inside and outside the formation of velocity difference, resulting in selfrotation motion. During the rotation process, the water inside the sludge particles is centrifuged, which accelerates the tendency to diffuse outwards and counteracts part of the diffusion resistance. It can be seen that the cyclone flow field characteristics provide a favourable basis for heat and mass transfer in the material drying process. Jamaleddine and Ray (2011) established a sludge cyclone drying model through computational fluid dynamics methods and particle flow dynamics theory, and theoretically analysed the feasibility of drying sludge in the cyclone drying equipment. Makela et al. (2017) used cyclone drying equipment for industrial sludge drying in paper mills and effectively reduced the moisture rate of sludge and concluded that the basic drying conditions could be met when the carrier gas temperature was higher than 40 °C. Grimme et al. (2017) carried out tests on cyclone drying of waste fibres and concluded that the feed rate was the most important factor affecting the drying efficiency of waste fibres and that the drying rate of cyclone drying equipment was higher compared to fluidised drying equipment. Makela et al. (2014) and Lee and Cho (2011) found that multi-stage cyclone drying can effectively improve the sludge cyclone drying effect. In summary, we believe that the joint action of the cyclone field and the thermal field must have a strengthening effect on the dryness of wet materials, and it is technically feasible to use the thermal field and the cyclone field for sludge cyclone drying. However, the published scientific literature on sludge cyclone drying technology is relatively small, and the superiority of the cyclone drying technology and the influence of the cyclone field on the drying performance need further in-depth research and analysis. In this paper, a cyclone drying system consisting of a cyclone and a drying tube is used to carry out an experimental study on sludge cyclone drying, in order to investigate the influence of test factors such as sludge moisture rate, sludge feed volume, carrier gas temperature, carrier gas flow rate on the cyclone drying performance of sludge.

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27

3.2 Cyclone Drying System and Test Materials 3.2.1 Cyclone Drying System and Test Materials Figure 3.1 shows a schematic diagram of a cyclone drying system consisting of a heater, cyclone drying equipment, cyclone separator, high pressure fan, thermometer, differential pressure gauge and vortex flowmeter. Heater heats the carrier gas, cyclone separator is used to collect the dried particles, thermometer and differential pressure gauge measure the system temperature and pressure drop, and vortex flowmeter is used to measure the amount of carrier gas when the system is in operation. The cyclone drying equipment consists of a dry cyclone with a drying tube. When the high pressure fan is in operation, the outside air volume is drawn into the heater for heating. The heated carrier gas carries the sludge particles for cyclone drying in the cyclone drying equipment and is finally separated by the cyclone separator. The drying cyclone consists of an infeed port, a column section, a cone section and a vortex finder. A schematic diagram of the structure of the cyclone drying equipment is shown in Fig. 3.2 and the specific structural dimensions are shown in Table 3.1. When cyclone drying is carried out, the sludge particles enter through the tangential inlet of the cyclone and exhibit a cyclonic motion in the cyclone. When the sludge particles run to the cone section of the cyclone, they enter the drying tube through the vortex finder. Compared to the vortex finder, the drying tube has an abrupt change in cross-sectional area, and the carrier gas and particles run at a reduced speed, rotating at low speed. The drying process is shown in Fig. 3.3, the sludge particles are subjected to a strong centrifugal force field, the wet sludge particles do cyclonic motion and spin motion, so that the sludge particles and hot carrier gas for heat

Fig. 3.1 Cyclone drying system

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Y. Zhang et al.

Fig. 3.2 Cyclone drying equipment

Table 3.1 Structural dimensions of cyclone drying equipment

Structure Drying cyclone inlet diameter/mm

Size 44

Dry cyclone column section diameter/mm

150

Dry cyclone column section height/mm

170

Dry cyclone cone section taper/°

30

Dry cyclone cone bottom diameter/mm

80

Dry cyclone overflow pipe diameter/mm

55

Dry cyclone overflow pipe length/mm

240

Dry cyclone height/mm

300

Drying tube diameter/mm

150

Length of drying tube/mm

500

3 Experimental Study on Sludge Depth Drying Under Dual Physical Fields

29

Fig. 3.3 Cyclone drying state of sludge particles

transfer, under the action of the cyclonic field, the mass transfer effect is further enhanced, thus accelerating the diffusion of moisture.

3.2.2 Experimental Materials Wet sludge with a moisture rate of approximately 85% and dry sludge with a moisture rate of approximately 20% were mixed and stirred to obtain the sludge particles required for the experiment. The average moisture rate of the sludge was 52.5% and the sludge particle size ranged from 2 to 5 mm. The sludge samples required for the experiments are shown in Fig. 3.4.

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Fig. 3.4 Experimental material

3.3 Experiment Results and Analysis 3.3.1 Influence of Sludge Moisture Rate on Sludge Cyclone Drying Performance In order to investigate the drying performance of sludge with different feed moisture rates in the drying system, sludge particles with moisture rates of 40, 45, 50, 55 and 60% were configured. Figure 3.5 shows the state of the sludge particles with different moisture rates and Fig. 3.6 shows the state of the sludge particles after image processing. As can be seen from the graphs, when the sludge moisture rate is below 50%, the sludge appears granular and looser, while the grey scale graph shows a clear gap between the sludge particles and a more uniform particle distribution. When the sludge moisture rate is greater than 50%, the viscosity of the sludge gradually increases and the agglomeration effect is enhanced. To investigate the effect of sludge moisture rate on drying performance, the test conditions were set at a sludge feed volume of 10 kg/h, a feed time of 15 min, a carrier gas flow rate of 200 m3 /h and a carrier gas temperature of 80 °C. Figure 3.7 shows the influence of sludge moisture rate on the effect of sludge cyclone drying. It can be seen from the figure that the discharge moisture rate increases with the increase of sludge moisture rate, when the sludge moisture rate is 40%, the discharge moisture rate is the lowest, 20.24%; when the sludge moisture rate is 60%, the discharge moisture rate is the highest, 33.20%. The graph also shows that when the sludge moisture rate of the feed is less than 50%, the discharge moisture rate is around 20%.

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31

Fig. 3.5 State of sludge particles with different moisture rates

Fig. 3.6 Grey scale diagram of sludge particles with different moisture rates Fig. 3.7 Influence of sludge moisture rate on sludge cyclone drying performance

3.3.2 Influence of Feed Volume on Sludge Cyclone Drying Performance In order to investigate the effect of feed rate on the performance of sludge cyclone drying, the response of feed volume on discharge moisture content was analysed at 5, 7.5, 10, 12.5 and 15 kg/h factor levels. The test conditions were: temperature 80 °C, carrier gas flow rate of 200 m3 /h, feed time of 15 min and sludge moisture rate 52.5%.

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Fig. 3.8 Influence of feed volume on sludge cyclone drying performance

Figure 3.8 shows the graph of the influence of the feed volume on the effect of sludge cyclone drying, from which it can be seen that the discharge moisture rate increases rapidly with the increase of the feed volume. When the feed rate is greater than 12.5 kg/h, the discharge moisture rate is higher than 30%. In order to reduce the discharge moisture rate as much as possible, it is considered more appropriate to have a feed volume lower than 12.5 kg/h.

3.3.3 Influence of Carrier Gas Temperature on Sludge Cyclone Drying Performance As one of the most critical factors in sludge drying, the analysis of the effect of different carrier gas temperatures on the drying performance of sludge has an important influence on the analysis of the drying effect of sludge cyclone drying systems. Using the carrier gas temperature as a research factor, 50, 65, 80, 95 and 110 °C were selected as the factor levels for the tests. The test conditions were: feed volume 10 kg/h, carrier gas flow rate of 200 m3 /h, average sludge moisture rate 52.5% and feed time 15 min. Figure 3.9 shows the effect of carrier gas temperature on the sludge cyclone drying effect, from which it can be seen that the sludge discharge moisture rate gradually decreases as the carrier gas temperature increases. It is important to note that there is an obvious abrupt change in the response of the sludge cyclone drying effect to the carrier gas temperature, i.e. when the carrier gas temperature is below 80 °C, the sludge drying effect is poor, with the average moisture content ranging from 40 to 45%. When the temperature rises above 80 °C, the sludge discharge moisture rate decreases rapidly and is below 20%. When the carrier gas temperature is raised to 110 °C, the sludge discharge moisture rate drops to 13.4%. When considering the

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33

Fig. 3.9 Influence of carrier gas temperature on sludge cyclone drying performance

cost of drying, the carrier gas temperature should not be lower than 80 °C when cyclone drying of sludge is carried out.

3.3.4 Influence of Carrier Gas Flow Rate on Sludge Cyclone Drying Performance The hot carrier gas is both the power source and the heat source basis for sludge cyclone drying. The carrier gas flow rate not only affects the performance of the flow field, but also has an important influence on the temperature field. The effect of the carrier gas flow rate on the drying performance was investigated using the carrier gas flow rate as the study factor, with the factor levels set at 140, 170, 200, 230 and 260 m3 /h. The test conditions were: carrier gas temperature 80 °C, feed volume 10 kg/h, average sludge moisture rate 52.5% and feed time 15 min. Figure 3.10 shows a graph of the effect of the carrier gas flow rate on the sludge cyclone drying effect, from which it can be seen that the discharge moisture rate decreases rapidly with increasing carrier gas flow rate. However, when the carrier gas flow rate reaches 260 m3 /h, the discharge moisture rate tends to increase again. The increase in the carrier gas flow rate represents an increase in the calorific value of the system and the amount of heat available to the sludge particles, so that the discharge moisture rate decreases. When the carrier gas flow rate is too high, the axial velocity increases in the cyclone drying system, which means that the residence time of the sludge particles in the drying system decreases, thus reducing the drying effect. Therefore, at a carrier gas flow rate of 260 m3 /h, the discharge moisture rate tends to rebound. Therefore, the carrier gas flow rate should not exceed 230 m3 /h under the existing test conditions and system parameters.

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Fig. 3.10 Influence of carrier gas flow rate on sludge cyclone drying performance

3.4 Conclusion In order to study the specific influence of the cyclone field on the drying performance, this paper proposes a sludge cyclone drying system consisting of a cyclone and a drying tube, and conducts a sludge cyclone drying test study for this system, and obtains the following conclusions. (1) The dual physical fields of the cyclonic and temperature fields substantially enhance the rate of heat mass transfer to the sludge particles. The shear breaking effect of the cyclonic field exposes some of the moisture directly, which in turn enhances the drying effect of the sludge. (2) The sludge discharge moisture rate is inversely proportional to the feed volume and the sludge moisture rate. The more the feed volume, the higher the discharge moisture rate, the worse the sludge crushing and drying effect. When the feed volume is below 10 kg/h and the sludge moisture rate is below 50%, the discharge moisture rate remains at around 20%, while when the sludge moisture rate is 60%, the sludge discharge moisture rate rises to 33%. (3) The sludge discharge moisture rate decreases with the increase of the carrier gas flow rate and the carrier gas temperature. When the carrier gas temperature is 110 °C, the sludge cyclone drying effect is optimal, and the sludge discharge moisture rate is 13.4%.

References Dou DY, Qiu ZY, Yang JG (2022) Parameter optimization of an industrial water injection hydrocyclone in the Taixi coal preparation plant. Int J Coal Prep Util 42(8):2357–2365

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Grimm A, Elustondo D, Makela M et al (2017) Drying recycled fiber rejects in a bench-scale cyclone: influence of device geometry and operational parameters on drying mechanisms. Fuel Process Technol 167:631–640 Huang Y, Li JP, Zhang YH et al (2017) High-speed particle rotation for coating oil removal by hydrocyclone. Sep Purif Technol 177:263–271 Iticescu C, Georgescu PL, Arseni M et al (2021) Optimal solutions for the use of sewage sludge on agricultural lands. Water 13(5):585 Jamaleddine TJ, Ray MB (2011) The drying of sludge in a cyclone dryer using computational fluid dynamics. Drying Technol 29(12):1365–1377 Lee JE, Cho EM (2011) A study on air jet drying for water content reduction of sludge. Korean J Chem Eng 27(6):1822–1828 Ling W, Xing Y, Hong C et al (2022) Methods, mechanisms, models and tail gas emissions of convective drying in sludge: a review. Sci Total Environ 845:157376 Makela M, Edler J, Geladi P (2017) Low-temperature drying of industrial biosludge with simulated secondary heat. Appl Therm Eng 116:792–798 Makela M, Geladi P, Larsson SH et al (2014) Pretreatment of recycled paper sludge with a novel high-velocity pilot cyclone: effect of process parameters on convective drying efficiency. Appl Energy 131:490–498 Swierczek L, Cieslik BM, Konieczka P (2018) The potential of raw sewage sludge in construction industry—a review. J Clean Prod 200:342–356 Wu BR, Dai XH, Chai XL (2020) Critical review on dewatering of sewage sludge: influential mechanism, conditioning technologies and implications to sludge re-utilizations. Water Res 180:115912 Xing L, Jiang MH, Zhao LX et al (2021) Design and analysis of de-oiling coalescence hydrocyclone. Sep Sci Technol 57(5):749–767 Yang XF, Zhu XM, Gao W et al (2022) Effect of low-temperature thermal drying on malodorous volatile organic compounds (MVOCs) emission of wastewater sludge: the relationship with microbial communities. Environ Pollut 306:119423

Chapter 4

Challenges of the Water Crisis in the Arab Gulf Countries (2011–2021) Sura Taha Al-Qasiem Al-Harahsheh and Mohammed Torki Bani Salameh

Abstract This study aimed at analyzing and diagnosing the water sector in the Gulf Cooperation Council Countries, in terms of identifying water sources, internal and external determinants and challenges to Gulf water security. It also aimed at showing the impact of Gulf water security on the national security of the Arab Gulf states. It used the historical and the descriptive statistical approaches. It concluded that the six Arab Gulf countries are similar in the average annual rainfall, the low rate of groundwater, the weakness of the strategic water reserve with the excessive depletion of groundwater in all countries of the Arab Gulf states, and the rate of extraction exceeds the rate of natural recharge of reservoirs. It concluded that the Gulf countries suffer from a severe water deficit with the increasing rates of water consumption, and the Gulf countries are afraid of water projects proposed to solve the water deficit for fear of political exploitation of those projects. Keywords Water resources in the Arab Gulf countries · Water balance · Gulf water security · Gulf national security · The future of water in the Arab Gulf countries

4.1 Introduction The Arab Gulf countries have a strategic geopolitical advantage (political, economic and geographical), as they overlook the Strait of Hormuz, which is one of the most important international shipping routes, and they contain huge reserves of oil and natural gas. The Arabian Gulf region also has great strategic importance for most countries, especially the great powers, as it is considered the “heart of the world” S. T. A.-Q. Al-Harahsheh Department of Earth Sciences and Applied Environment, Faculty of Earth and Environmental Sciences, Al Bayt University, Mafraq, Jordan M. T. B. Salameh (B) Political Science Department, Faculty of Arts, Yarmouk University, Irbid, Jordan e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_4

37

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S. T. A.-Q. Al-Harahsheh and M. T. B. Salameh

from a geopolitical point of view, due to the fact that it constitutes a major link for the global land, sea and air transportation networks, which make this region plays a fundamental role in maintaining global peace and security. Water in the Arabian Gulf region has an economic, social and political specificity, and it may extend to become a potential source of conflict in the region, which also makes it a security and military dimension. It relates to the lives of the countries and peoples of the region, and at the same time it is intertwined with the region’s political problems (Salameh et al. 2021). This makes the issue of water security one of the pillars of national security for the Arab Gulf states. In the Arab Gulf region, where water scarcity is the basis, and the contradiction between the limited water resources and the increasing demand for water, makes the issue of water a strategic issue of geopolitical importance, which makes those who lack it lose many of the factors of their economic, social and political strength and fortitude. The study aims to show the impact of Gulf water security on the national security of the Arab Gulf states. The problematic of the study revolves around the main question: “What are the strategies used by the Arab Gulf states to reduce the scarcity of water resources and how the Gulf political decision-maker deals with this problem?”.

4.2 The Reality of Water Security in the Arab Gulf States The Gulf Cooperation Council countries overlook four bodies of water: the Red Sea, the Arabian Sea, the Sea of Oman, and the Arabian Gulf (Statistical Center of the Gulf Cooperation Council 2018). The Arab Gulf countries suffer from water poverty and a high rate of evaporation, as the annual rainfall rate in the Arabian Gulf region ranges between 70 and 130 mm annually per capita per year (Eid 2011), with the exception of the mountain ranges in the southwest of the Kingdom of Saudi Arabia and the south of the Sultanate of Oman, in which the rain rate may reach more than 500 mm. Evaporation rates range between 1000 mm annually on the coastal strip and about 3000 mm annually in the desert areas. As a result, the issue of water has gained exceptional importance in the literature of political economy and geography (Salameh 2021). It has also occupied an advanced position in strategic studies. There is a consensus among economists, politicians, and geography experts that future wars will be due to the struggle over water resources, or the so-called white oil (Economic and Social Commission for Western Asia (ESCWA) 2019).

4.3 Sources of Gulf Water Security The desert constitutes (89.6%) of the total area of the Arabian Peninsula (Issa 2003), and there are two types of water resources in the Arab Gulf states: traditional natural sources, or what is called in the water literature, as “blue water,” and non-natural sources (dams and water desalination from the sea), and the amounts of precipitation

4 Challenges of the Water Crisis in the Arab Gulf Countries (2011–2021)

39

vary from one region to another according to the climatic and geographical factors. Saudi Arabia ranks first in the amounts of precipitation in the Arab Gulf countries, as the precipitation amounts ranged between (107.9–255.6) billion cubic meters per year. The Sultanate of Oman came in second place in the rate of precipitation, as the amounts of precipitation ranged between (24.4–57.5) billion cubic meter per year, followed by the United Arab Emirates in the rate of rainfall, as the amounts of precipitation ranged between (1.2–1.26) billion cubic meter per year, then the State of Kuwait at a rate of precipitation ranging between (1.3–980) million cubic meter per year, then the State of Qatar at a rate of 80 mm per year, while the State of Bahrain occupies the last rank in the amounts of precipitation, as it ranges The average precipitation amounts are about (40) million cubic meter during the years (2012–2018)1 . The Arab Gulf countries depend almost entirely on groundwater, in light of their possession of a strategic reserve of groundwater resources estimated at about 361.5 billion cubic meter, and this amount represents about 4.6% of the total Groundwater reserves in the Arab countries. Table 4.1 shows the total quantities of surface and fresh water available for use in the Arab Gulf states. Table 4.1 shows that Saudi Arabia contains the highest reserves of groundwater, followed by the Sultanate of Oman, then the State of Kuwait, then the State of Qatar, and the UAE comes in the fifth rank. Groundwater in the UAE is mainly non-renewable and suffers from high levels of salinity as a result of overdraft and high population. To cover the water deficit, the Gulf countries tended to cover the shortage of fresh water through seawater desalination plants, and building dams. More than 50% of the world’s desalination plants are located in the GCC countries, and the dependence on them is increasing2 . The percentage of water desalination in the State of Kuwait (62%) of its total water resources, the UAE (55.4%), Bahrain (54.5%), and Qatar (48.7%).The six Arab Gulf countries have sought to increase seawater desalination plants to meet the requirements of industrial and agricultural development. As shown in Table 4.1.

4.4 Water Balance in the Arab Gulf States The water balance means the balance of water supply (precipitation and groundwater) with the demand (domestic, agricultural and industrial consumption) during a certain period of time. There is an abundance of water when the supply of water is greater than the demand. While there is a water deficit when the required quantities of water are greater than the quantities supplied. This deficit is sometimes called the “water gap”. Table 4.2 shows the quantities of surface and fresh water extracted in the Arab Gulf countries (2010–2018).

1

Gulf Statistical Centre. https://dp.gccstat.org/ar/DataAnalysis. Orientation Towards Water Security in the Arab Region: Framing Water Security in The Arab Region, p. 27.

2

893.2000 1477.4793 5900.0201 7191.9506

Qatar

Kuwait

UAE

308.6501

UAE

850.8230

1433.8300

Kuwait

Bahrin

754.9116

Qatar

Oman

412.3000

Bahrin

5900.0201

1905.3791

Oman

Saudi Arabia

21,103.0000

Saudi Arabia

7364.5168

2264.4000

1477.4793

847.7000

855.3860

6321.9101

376.7999

1460.3800

783.3347

419.5000

1927.3040

22,478.0000

2013

Source Gulf Statistical Center, https://dp.gccstat.org/ar/DataAnalysis

Total fresh water supplied by industrial plants (million cubic meter)

Total fresh water ready for use (million m3 )

2012

7286.1437

2400.7900

1477.4793

847.7000

885.4712

6336.9101

431.2527

1602.9100

826.4900

429.7000

1973.0000

23,643.0000

2014

Table 4.1 Total quantities of surface and fresh water available for use (2012–2018)

7287.0984

2400.0000

1636.5924

847.7000

944.4212

7461.9141

451.7280

1484.7296

880.3770

430.3000

2006.2338

25,050.0000

2015

7256.1856

2838.0000

1734.7879

856.8000

1008.6582

7705.0000

469.9933

1557.4496

911.1792

436.2000

2032.6514

24,227.0000

2016

7475.0978

2835.8509

2066.9545

856.8000

1012.3640

7653.0000

493.9888

1614.3396

982.5374

438.9000

1905.3791

23,350.0000

2017

7477.7812

2835.8509

2066.9545

856.8000

1491.6390

7653.0000

513.0000

1608.7596

1037.8771

438.9000

1927.3040

25,993.0000

2018

40 S. T. A.-Q. Al-Harahsheh and M. T. B. Salameh

754.1500

UAE

179.1000

1786.5400

909.9300

250.2800 3536.0000

762.8900

250.0000

159.1000

102.0000

123.3700

2015

2639.0000

800.2200

250.0000

155.1000

102.0000

175.0000

2016

2562.0000

846.0200

250.0000

158.4000

102.0000

71.0000

2017

2501.0000

842.0000

250.0000

102.0000

89.0000

2018

1532.0000 197.0000 425.9018 632.6800

Bahrin

Qatar

Kuwait

UAE

637.2600

453.2145

204.9000

1532.0000

653.0800

482.2000

219.2000

1532.0000

676.9700

533.0000

241.6000

1532.0000

712.3600

557.0000

241.9000

1532.0000

723.4500

602.0000

239.2000

1532.0000

721.8900

637.0000

18,940.2350 20,395.0350 21,351.6300 22,647.6300 21,595.0000 20,567.0000 23,061.0000

1823.0000

786.9200

250.0800

182.2000

123.3700 102.0000

87.9650

2014

102.0000

2013

Oman

Saudi Arabia 1905.0000

Kuwait

Source Gulf Statistical Center, https://dp.gccstat.org/ar/DataAnalysis

Abstracted fresh groundwater (million m3 )

178.6000 250.2100

Qatar

Bahrin

Fresh surface water abstracted (million Saudi Arabia 204.7650 m3 ) Oman 102.0000

2012

Table 4.2 The amount of surface and fresh water extracted in the Arab Gulf countries (2010–2018)

4 Challenges of the Water Crisis in the Arab Gulf Countries (2011–2021) 41

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4.5 The Amount of Surface Water Extracted in the Arab Gulf Countries The UAE is considered the highest Arab Gulf country in the exploitation of extracted fresh surface water. The quantity is estimated at (1905.0000) million cubic meters for the year (2012), then it increased to (2501.0000) million cubic meters in the year (2018). Kuwait comes in the second place in the exploitation of extracted surface water, and the quantity is estimated at (842.0000) million cubic meters for the year (2018), up from (754.1500) million cubic meters for the year 2012. The State of Qatar ranked third in the level of water exploitation in the Arab Gulf countries, where it is estimated the existing exploited quantity is (250.2100) million cubic meters, which is the fixed percentage during the period (2012–2018). Saudi Arabia came in the fourth place, with an estimated exploited (204.7650) million cubic meter for the year 2012, then it began to contradict until it reached (89.0000) million cubic meters for the year 2018. Bahrain ranked fifth, as the quantities of exploited surface water decreased from (178.6000) million cubic meters for the year 2012 to the amount of (158.4000) million cubic meters for the year 2018. The Sultanate of Oman came in the sixth and last place, as the quantities of extracted water amounted to (102.0000) million cubic meters during the period (2012–2018)3 .

4.6 The Amount of Fresh Water Extracted in the Arab Gulf Countries Saudi Arabia is considered the highest Arab Gulf country in the exploitation of extracted fresh groundwater, and the quantity is estimated at (18,940.2350) million cubic meters for the year (2012), then it rose to (23,061.0000) million cubic meters in the year (2018). The Sultanate of Oman comes in the second place in the exploitation of extracted groundwater, and the quantity is estimated at (1,532.0000) million cubic meters, which is a constant percentage for the years (2012–2018). The State of Kuwait ranked third in the level of exploitation of fresh groundwater in the Arab Gulf countries, with an estimated exploited quantity of (632.6800) million cubic meters, for the year (2012), rising to (721.8900) cubic meters annually in (2018). The State of Qatar ranked fourth, as the extracted groundwater quantities were estimated at (425.9018) million cubic meters for the year 2012, and rose to reach (637.0000) million cubic meter for the year 2018. Bahrain ranked fifth, as the extracted groundwater quantities increased from (197.0000) million cubic meters for the year 2012, to the amount of (239.2000) million cubic meters for the year 2018. There is no data on groundwater extracted from the United Arab Emirates (Water Statistics in the Arab Gulf Countries 2021).

3

Gulf Statistical Centre. https://dp.gccstat.org/ar/DataAnalysis.

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4.7 Dams and Desalination Plants in the Arab Gulf States Saudi Arabia paid attention to the construction of dams, as it built about (200) dams. The storage capacity of dams increased from (1928.8659) billion cubic meter in the year (2012) to (2245.0000) billion cubic meter in the year (2018). Among the most important dams in Saudi Arabia is the (Jizan) dam, with a capacity of (86) million cubic meters, and the (Ajran) dam, which has a storage capacity of (56) million cubic meter. Most of the water supply comes from the annual mountain rains in the coastal mountain range, and the Tihama region along the Red Sea that covers the regions of Jizan, Asir and Medina (Emirates Center for Strategic Studies and Research 2013). Saudi Arabia suffers from the exposure of dams to a high rate of evaporation, and the deposition of silt, which needs dredging continuously and from time to time. Saudi Arabia also suffers from not exploiting this renewable resource in an organized manner and for agricultural use. The renewable resources of groundwater have the ability to maintain an active agricultural economy in a sustainable manner (Water Statistics in the Arab Gulf Countries 2016). Within the framework of the Sultanate of Oman’s strategic vision Oman (2041) to increase the Sultanate’s stock of groundwater, it has constructed (168) dams, including (44) dams to recharge groundwater (111) dams for storage, and (13) dams for protection from flooding of valleys (Hormuz Agency 2022). As a result, the design capacity of dams increased from (294.0938) million cubic meter in 2012 to (322.8000) million cubic meter in 20184 . As for the United Arab Emirates, there are (7) dams, whose design capacity increased from (89.3463) million cubic meter in 2012 to a capacity of (322.8000) million cubic meter in 2018. Some of these dams are used to feed groundwater, and some are used to benefit from rain and surface water, as groundwater reservoirs are recharged from the limited surface flows that originate from the central mountain range located in the southeastern region of the country. Moreover, the sedimentary reservoirs in the emirate of Fujairah are recharged by relatively large mountain rainfall in the coastal chain along the Arabian Gulf. The UAE spares no effort in enhancing the scope of water collection and providing safe drinking water (Al-Rashdan 2020). As the Arab Gulf countries embarked on the construction of desalination plants and sanitary water treatment plants to cope with the rapid urbanization and increasing population growth, the GCC countries embarked on major wastewater treatment projects starting with wastewater collection and proper treatment, and the reuse of treated wastewater.

4

Gulf Statistical Centre. https://dp.gccstat.org/ar/DataAnalysis.

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4.8 The Impact of Water Security on Gulf National Security Water security is one of the strategic issues related to the national security of countries, since it affects the lives of peoples and individuals, and the entity and sovereignty of the state. Countries strive to secure the water needed for the population and agricultural and development projects necessary for the sustainability, development and modernization of the state. In order to preserve the water wealth of each country, the necessary laws and regulations have been enacted for this wealth and its sustainability, and it is considered a national asset. In this section, we will discuss the impact of water security on Gulf national security.

4.9 The Concept of Gulf National Water Security After the end of the Cold War, and the change in the structure of the international system, interest in international relations changed from concepts linked within the nation-state to transnational issues such as issues of international terrorism, terrorist groups, cyber warfare, minorities, water issues and its scarcity, especially in some regions and countries at the global level (Al-Harbi 2008). This is what moved the issue of water and financial security from the national and local dimension to the international dimension, and considering this as one of the international problems that have a local and international impact at the same time. The lack of water resources with the increasing requirements of development and population may lead to the occurrence of regional and international conflicts, threatening the strong local and regional security of states. Water security is defined as “achieving self-sufficiency in water in a sustainable manner, according to generally accepted international rates (Ghoneimi 2008)”. Water security is also stability in the status of water resources so that there is a balance between the supply of water and the demand for it (Khaddam 2001). The concept of water security is based on sub-indicators on the percentage of the population that can access improved water sources in a sustainable way, the availability of water needed for the agricultural sector, and the percentage of renewable water resources that exceed the volume of consumption, and risk management of water shortage through the volume of dams. Based on the foregoing, the primary goal of water security is to achieve adequacy, sustainability, justice, and management, including the option of future surface water development of water resources, and this includes many options through large, medium, and small dams or rainwater harvesting, and the option of developing shallow and deep water through artificial injection or groundwater reservoirs, or the development of non-traditional water resources. It also includes the freedom of water transfer between basins and the option of importing water (Ahmed 1993). There is a close link between national security and water security. Without an abundance of water, it is difficult to establish agricultural projects, and it is closely

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related to water resources, which are scarce and limited in the Arab Gulf states. The high levels of desertification and drought in the Arab Gulf countries also increase the fragility of food security. Food stability is an integral part of the national security of the Arab Gulf states, and the availability of food means that there are sufficient quantities of food of good quality, secured through local production or import, or through food aid. Food availability is measured, in the broadest sense, by the adequacy of supply as the proportion of dietary energy required (Economic and Social Commission for Western Asia 2017b). Food security is still a major future concern for the Arab Gulf countries. Agricultural production rates in the Arab Gulf countries are still relatively low and do not exceed 1%, and are greatly affected by climate fluctuations and prices in global food markets. In the Arab Gulf countries, the percentage of imports of foodstuffs rises significantly, as the average dependence on imports reached (86%) for the Arab Gulf countries, and the import concentration coefficient is (85%). This constitutes a factor of instability in food security, especially in light of the crises that occurred, which led to a significant rise in food prices, and affected households and government budgets in food-importing countries, such as the global food crisis in 2007 and 2008, and the crisis in the year (2022) as a result of the Russian invasion of Ukraine, which resulted in stopping global supplies of grain and doubling their prices, as well as the prices of vegetable oils. The rates of food exposure in the Arab Gulf countries ranged between (82%) for the United Arab Emirates, and 84% for the State of Bahrain, the Sultanate of Oman (70%), Qatar (83%), Kuwait (70%), and Saudi Arabia (72%). The average for the Arab Gulf countries was (75%) for the period from (2013–2014). If the indicators of the loss of food security in the Arab Gulf countries are linked with the loss of water security. It is possible to realize the extent of the national exposure of the Arab Gulf countries, as their strategic water reserves are only sufficient for a few days in emergencies that may occur in the GCC countries. The strategic reserve of water in the UAE reaches (30) days, in Kuwait (10) days, in the city of Riyadh (3) days and in Bahrain (one day). There was a power outage in the year (2004) in the State of Bahrain in what was called Black Monday. As a result, the desalination plants stopped, and by the end of the day, the country’s water reserves have reached a point of depletion (Al-Yasiri 2022).

4.10 The Political and Economic Impact of Gulf Water Security The water issue is considered one of the issues of national security, and it is considered a major issue in international relations and a source of regional conflicts. It was the main source of the Iraqi-Iranian war over the sharing of the Shatt al-Arab in 1980, a war that the Arab Gulf states paid most of their economic and political costs.

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4.10.1 First: The Impact of Water Security from a Political Point of View The state’s water security plays an important role in enhancing its political capabilities, and the independence of its national decision. The higher the state’s water security score, the more independent its political decision will be. This paper will discuss the impact of water security on the Arab Gulf states from a political point of view.

4.10.2 The Political Employment of the Water Issue and Water Dependency Abroad The geographical neighboring countries of the Arab Gulf countries enjoy a great abundance of water (Turkey, Iran, Iraq, Syria). Therefore, these countries will be the best alternative in the event of water scarcity in the Arab Gulf countries. The owners of this perception proceed from the fact that the water problem can be solved in a peaceful, regional and joint manner, and that is through international efforts, provided that there is goodwill and intentions among countries and the exchange of benefits for all. The Human Development Report (2006) showed that the conflict over water or the so-called water wars, and that competition over water resources does not necessarily lead to the outbreak of armed conflicts. Cooperation between countries across borders in water issues is the most widespread in a large number of countries in the world, including Arab countries (Belqasim and Tawfiq 2015). Turkey is one of the richest countries in water, and it can contribute to solving the problem of water scarcity in the Arab Gulf countries by extending water pipes for long distances under the sea, according to the (Water of Peace) project, which requires the transfer of surplus water from the Turkish Ceyhan and Sihun rivers through pipes to supply countries Arabian Gulf water (Aziz and Fawzi 2007). The Peace Pipes project was one of the most important economic projects that Turkey sought to achieve in the Arab countries in the Fertile Crescent and the Arabian Peninsula. The project, in the event of its implementation, will provide up to (2600) million cubic meters annually for the Arab Gulf countries, including (800 million cubic meters) for Saudi Arabia, (600) million cubic meters for the states of Kuwait and the Emirates, and (200) million cubic meters annually for the countries of Bahrain, Qatar and Oman. However, Arab and Gulf reservations about the project for political reasons, and the high financial cost and technical problems make the establishment of this project a difficult issue to achieve (Al-Abbasi 2012). However, the political and economic motives behind its adoption of such projects, especially in light of its endeavor to strengthen and expand the circle of control in the region, increases the Gulf countries fear of the political exploitation of the water issue in the event of political differences between Turkey and GCC countries (Shalabi and Majzoub 1997). This is also related to the projects proposed by Iran to supply water to the Arab Gulf states, such as the

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Green Pipe project in 1991 to supply the State of Qatar with 135 million cubic meters annually (Qablan 2021), and a project to supply the State of Kuwait with water from the Karun River in northwestern Iran in the year (2000), and to supply Kuwait with (25 million cubic meters) of water annually. These project proposals make the Arab Gulf countries vulnerable to political blackmail according to certain conditions by those countries, especially in the case of political or economic differences between those countries themselves, which represents a restriction on their political flexibility and freedom of political movement regionally and globally. Water supply projects were also proposed for the Gulf countries from Iraq, Lebanon and Sudan, but the high costs of the projects, and the fear of their political exploitation put an end to all these projects (Al-Abbasi 2007). These proposed projects, despite their technical and economic costs, may be of great importance for the Arab Gulf states to study them seriously and in-depth, away from political fears, especially in light of globalization and economic integration between countries. The proposed Arab projects may be the most suitable projects compared to the rest of the other projects, in terms of financial cost on the one hand, and in terms of fear of employment and political extortion on the other hand.

4.10.3 Second: The Loss of Water Security Due to Iran’s Nuclear Activity, and the Possibility of Polluting the Gulf Waters The Arab Gulf countries depend to a high degree on desalination plants from the sea. Due to the presence of Iranian nuclear plants close to the shores of the Arab Gulf countries, the possibility of exposure of these nuclear facilities to natural disasters or human disasters (a devastating earthquake, a design error, a lack of adequate maintenance, an exposure to a cyber-attack) may have a high probability of leading to radioactive leakage. For example, the Bushehr nuclear reactor is close to the eastern coast of the Arabian Gulf region off the State of Kuwait, and it is only 200 km away, and the area in which the reactor is located is seismically active. It is located in an area highly prone to earthquakes and at the meeting point of three seismic rift lines: the Eurasian rift, the Arab rift, and the Iranian rift. Therefore, in the event of any nuclear radioactive leakage, it may affect the coastal areas of Kuwait, Saudi Arabia, Bahrain, Qatar, the Emirates, and the Omani Musandam Peninsula (Al-Turki 2013). It is worth mentioning that the accidents of the Iranian nuclear reactors had already occurred in the year (2010) when the Iranian nuclear site Natanz was subjected to a cyber-attack through the Stuxnet virus and severely damaged the centrifuges. The same applies in the year (2020) when a fire occurred in the same facility (Kishk 2020).

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4.10.4 Third: The Possibility of a US-Iranian War and the Exposure of Iranian Nuclear Facilities to Attack The Arab Gulf region is an area of regional and international tension and conflict between the United States and the Arab Gulf states on the one hand, and Iran on the other. As Iran is trying to dominate the Gulf states militarily and to possess nuclear weapons, the United States and Israel are pressing towards preventing it from acquiring nuclear weapons and stopping uranium enrichment by peaceful means (Al-Ali March 2022). Any war on Iran, whether from the United States or Israel against Iran’s nuclear facilities, will lead to radioactive and nuclear leaks into the Gulf waters, which means contamination of drinking water with radioactive materials, and contamination of fisheries, and depriving the peoples of the region of the only source of water on which most of the Arab Gulf countries have depended on for many years, especially in light of the technical and technological inability of the desalination plants in the Arab Gulf countries to treat radioactive and nuclear leaks in the event of their occurrence, and the stations are not equipped technically and technologically to deal with the accumulation of large quantities of Marine algae. In the past, the occurrence of many cases led to the closure of some stations and the poor performance of others. The desalination plants are also unable to handle the oil spill and remove oil and gas pollutants that may occur (Al-Salami 2022).

4.10.5 Fourth: The Increasing Rates of Food Exposure and External Dependency The Arab Gulf countries have depended on global markets to secure their basic food needs, which far exceed the capacity of domestic production. In the period 2010– 2013, all Arab Gulf countries recorded a deficit in the total food trade balance, and one of the countries that recorded the largest deficit in food trade was the Kingdom of Saudi Arabia, where the deficit amounted to approximately $15 billion in the period (2010–2013), equivalent to one-fifth of the total food trade deficit in the region. It is followed by the United Arab Emirates, where the deficit amounted to 8 billion dollars (Economic and Social Commission for Western Asia Arab Horizon 2017a). It also shows the global food security index, which is based on three main subindicators related to food security, which are affordability, food availability, food quality and safety. According to the affordability index, the Arab Gulf countries are ranked globally as a result of their economic wealth and high financial capabilities as the GCC countries occupy the top ten positions, with the exception of Bahrain and the Sultanate of Oman, and this is due to many factors, the most important of which are (low customs tariffs on agricultural imports, the presence of food safety nets by governments, strong government support for food security net programs,

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low customs tariffs on agricultural imports)5 . As for the food availability index, which measures the adequacy of food supplies for a country or a region, the risks of disruption or interruption of supplies, the ability to distribute food and the ability to expand agricultural production, the Arab Gulf countries ranked poorly as they ranked (99 out of 113 countries) at the aggregate level, and less than 100 at the level of each country. With regard to the food quality and safety index, the GCC countries perform relatively better, ranking 30 on average out of 113 overall.

4.11 The Impact of Water Security from an Economic Point of View In order to maintain the water security of the state, it must pay high economic costs in order to sustain its water resources. We will discuss in this requirement the economic impact of water security on the Arab Gulf states.

4.11.1 First: The High Economic Costs The GCC countries are among the most dependent countries in the world on water desalination, as they own (75%) of the desalination plants at the global level (United Nations 2019). The significant increase in the dependence of the Arab Gulf states on desalination of water from the sea has contributed to the high cost of production and transportation, and to the exhaustion of the general budget of the Gulf states. The cost of establishing one desalination plant ranges between 200 and 500 million dollars. The investments required for water desalination in the Gulf countries were estimated at about $10 billion over the next eight years, and about $23 billion in the second decade of the current century, and jumping to $40 billion during the third decade. Based on international energy costs, the cost of producing one cubic meter of fresh water in the Gulf countries is estimated at between 1 and 1.5 dollars, for desalination plants with a production capacity of about 2000 cubic meters per day, in addition to the costs of energy, operation, and maintenance. The total cost recovery rate is (8%) only of the total cost (Al-Rashidi 2015). The cost of producing and transporting one cubic meter of desalinated water is higher than that of the surface and the groundwater, and ranges between (70 cents and One US dollar) (Al-Khaleej Online 2021). Saudi reports indicate that the financial cost of supplying water for municipal uses jumps to 10% of the total budget, or 3% of the GDP by 2040. In 2040, there will be a need of more than 8 million barrels of crude oil per day for water desalination operations. With regard to the energy consumption required for the stations, the GCC countries are among the countries that consume the highest levels of 5

Global Food Security Index: https://impact.economist.com/sustainability/project/food-securityindex/Index.

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energy. In the State of Bahrain (30%), the total energy use goes to desalination plants, and in Saudi Arabia (10%), the total fuel consumption goes to pumping groundwater. In addition to the increasing and high corrosion rates of water desalination plants in the Gulf and the Red Sea compared to their counterparts in the countries of the world, and the decrease in their operational life from (25) years to (8) years. This means the need for huge financial allocations to maintain the sustainability and maintenance of these stations. The low rate of recovery of the cost paid for water (water fees) in most GCC countries has led to wasteful use, problems related to heavy dependence on government subsidies, and insufficient operation and maintenance budgets, which has led to delays in the maintenance of desalination systems, and the related decline in the level of service over time in the GCC countries. For example, the volume of government subsidies in the State of Kuwait for water increased from (1310) million dollars in (2010) to (1860) million dollars in (2015) and to (2638) million dollars in the year (2020) and (3735) million dollars in the year (2025), at a rate of (4.8%) of the Kuwaiti GDP6 .

4.11.2 Second: Environmental Pollution The desalination of water from the sea has led to negative repercussions on the ecosystem and its main sources such as air and water pollution, etc. Despite the large requirements of the desalination process in terms of energy and money and its waste harmful to the environment, sea water desalination is a very expensive industry, due to the precise technology it adopts, the amount of energy it consumes, in addition to the outputs of the desalination plants represented by the brine solution, the accompanying gaseous emissions, and the extreme heat of the drained water. These emissions affect the animal and fish environment and the organisms in that sea, and the geographical extent of the impact varies from one place to another depending on the nature of the geological formations (coral reefs, rocks, sand). On its way to the consumer, the desalinated water washes away some harmful materials left over from the desalination process and technology (Al-Mahmoud 2018).

4.12 The Future of Gulf Water Security In light of considerations of population increase and the expansion of development and urbanization projects, the GCC countries will suffer from a severe water deficit in the future with relative disparity among them. With regard to the deficit in the water balance, it is expected that the water deficit will be inclusive of all the GCC countries, as it is expected that in Bahrain it will be in the range of (174 million cubic meter) 6

World Bank, Report on the Water Sector Assessment in the Arab Gulf Countries, previous reference, p. 80.

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during the period (2010–2050), In the State of Kuwait, it will be in the range of (835 million cubic meter). In the Sultanate of Oman, up to (1145 million cubic meter). In the State of Qatar, it will be around (91 million cubic meters). In Saudi Arabia, the water deficit will be around (10,600 million cubic meters) and in the UAE, around (241 million cubic meters). This means that the Kingdom of Saudi Arabia, the State of Kuwait, the Sultanate of Oman, and the UAE will be at the forefront of the GCC countries that suffer from a high-water deficit. While the State of Bahrain and the State of Qatar will be among the GCC countries with the least water deficit.

4.13 Conclusions All GCC countries suffer from a water deficit that is increasing over the years. In order to cover this worsening water deficit, the GCC countries have tried to provide possible alternatives from water sources, through the construction of dams, rationalization of consumption and desalination of sea water and sewage water. It has been able to expand significantly in desalination plants for water from the sea and waste water. Despite the high financial cost of desalinating water from the sea. The study concluded the followings: 1. The six GCC countries are close and similar in terms of desertification rate and annual lack of rain, and the water balance of the GCC countries shows that the Sultanate of Oman and Saudi Arabia are the only two countries that contain reserves of non-renewable groundwater, as Saudi Arabia contains (428,400) billion cubic meters, while The Sultanate of Oman contains (102,000) billion cubic meters. 2. Weakness of the strategic water reserve in the Gulf Cooperation Council countries with the excessive depletion of groundwater in all GCC countries, and at an extraction rate that exceeds the rate of natural recharge of reservoirs. 3. Political exploitations of the issue of water and water external dependency, the loss of water security due to Iran’s nuclear activity, and the possibility of polluting the waters of the Gulf. The increasing rates of food exposure and external dependency are political and economic costs that the Arab Gulf states may pay in order to sustain their water resources. 4. The GCC countries suffer from a severe water deficit now and in the future, with a relative disparity between them in terms of consumption rates, which are expected to increase significantly in the future.

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Kishk A (2020) Iranian nuclear facility accidents and Gulf precautionary measures. Akhbar AlKhaleej, at the following link: http://www.akhbar-alkhaleej.com/news/article/1215676 Qablan M (2021) Qatar’s foreign policy: strategy confronting geography, 1st edn. Arab Center for Research and Policy Studies, Doha, p 137 Salameh M (2021) Dam wars: are Ethiopia, Turkey, and Iran leading to water Armageddon? Middle East Policy 28:147–157. https://doi.org/10.1111/mepo.12547 Salameh MTB, Alraggad M, Harahsheh ST (2021) The water crisis and the conflict in the Middle East. Sustain Water Resour Manage 7:69. https://doi.org/10.1007/s40899-021-00549-1 Shalabi H, Majzoub T (1997) Turkey, the Euphrates waters and international law. In: Al-Quwatli MO (transl) Waters in the Middle East: legal, political and economic essays. Syrian Ministry of Culture, Damascus, pp 265–266 Statistical Center of the Gulf Cooperation Council (2018) Statistical Atlas of the Gulf Cooperation Council, Third Issue, p 18. See also: Ibtisam Mahran, Water bodies overlooked by the Gulf countries, Al-Mersal, January 20, 2020, at the following link: https://www.almrsal.com/post/ 1014871 United Nations Economic and Social Commission for Western Asia ESCWA (2019) Eighth water and development report water-related sustainable development goals in the Arab region, Beirut, p 28 Water Statistics in the Arab Gulf Countries (2016) Annual Bulletin, Issue No. (1), p 54 Water Statistics in the Arab Gulf Countries (2021) Annual Bulletin, Issue No. (1)

Chapter 5

Learned Lessons from Japanese Experiences in Planning and Managing Fishing Ports Mahmoud Sharaan, Moheb Iskander, Kazuo Nadaoka, Abdelazim Negm, and Mona G. Ibrahim

Abstract This paper comes from a series of studies investigating the Egyptian fishing ports’ challenges, opportunities, planning, and environmentally relevant issues since 2015. This study aims to enhance the Egyptian coastal fisheries and improve their efficiency, one of Egypt’s suggested strategic initiatives for 2030, based on the Japanese experiences and practices in planning and managing their fishing ports, which are acquired during the field visit to some Japanese fishing ports. It was obvious that Japan is implementing strict management procedures and is going straight forward to better operational efficiency of its fishing ports. Promoting the Egyptian coastal fishing ports infrastructure considering the environmental issues based on proper Japanese experience to our culture is expected to support its operation more eco-efficient and sustainable and enhance the SDGs 8, 9, and 14.

M. Sharaan (B) · M. G. Ibrahim Environmental Engineering Department, Egypt-Japan University for Science and Technology, Alexandria 21934, Egypt e-mail: [email protected]; [email protected] M. Sharaan Civil Engineering Department, Faculty of Engineering, Suez Canal University, Ismailia 41522, Egypt M. Iskander Department of Hydrodynamic, Coastal Research Institute, National Water Research Center, Alexandria 21514, Egypt K. Nadaoka Professor Emeritus, Tokyo Institute of Technology, Tokyo, Japan A. Negm Department of Water and Water Structures Engineering, Faculty of Engineering, Zagazig University, Zagazig 44519, Egypt e-mail: [email protected] M. G. Ibrahim Professor, Environmental Health Department, High Institute of Public Health, Alexandria, Egypt © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_5

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Keywords Japanese fishing ports · Egyptian fishing ports · Coastal fisheries · Port planning · Environmental issues · SDGs

5.1 Introduction Fishing ports have significant roles in promoting the fishing industry. They are sources of national food, labor, and income for many people. Fishing ports interface between harvesting fish stocks and their consumption (Sciortino 2010). Besides the unloading, handling, and marketing of fish, a fishery port can comprise industrial areas where fish are processed and serviced and maintenance facilities for vessels, nets, and gear. In addition, the fishing vessels’ services are not limited to a safe mooring to discharge the catch. This heterogeneous mixture of port activities demands a strong cross-sector collaboration at the planning stage to guarantee that the resulting infrastructure is suitable for the activities and managed properly (Ligteringen 2012). Associated operational environmental issues are globally ubiquitous regardless of differences in economic development; without robust protective measures, many of the hard-won benefits by well-intentioned planners are expected to be lost (PIANC 1998). There are many examples where developing new or existing fishing ports can pose environmental risks. The haphazard site can lead to losses of productive habitats such as mangroves and coral reefs. Disruption of local currents caused by the construction of breakwaters, jetties, groins, etc., can alter the patterns of erosion and deposition, resulting in damage to coastal infrastructure (PIANC 1998). Accumulated sediment is considered a major environmental issue, representing a severe obstacle to fishing boats’ navigational processes at the port entrance and during handling processes (Frihy 2001; Sharaan et al. 2018; Sharaan and Negm 2017). Conventional management has proved insufficient measures to deal with the fishing ports’ problems, such as sedimentation, pollution, port infrastructure, and facility degradation. Environmental monitoring is essential for understanding the quality of aspects and procedures. It could benefit greatly when they are well organized and handled with other port managerial sectors. The United Nations Sustainable Development Goals (UNSDGs; https://sdgs.un. org/goals), specifically goal 14 (Life below water), focus on conserving and sustainably using the oceans, seas, and marine resources. The predominance of unsustainable habits (overfishing, pollution, and illegal fishing) may deteriorate the marine environment, restricting developing countries from maximizing their marine resources (Okafor-Yarwood 2019). Goals 1 and 2 are (No poverty and zero hunger) also concerned with eradicating hunger and poverty and grantee proper food security, all of which might be achieved with a bountiful supply of fish. Also, coastal fishing substantially contributes to the national revenue of many developing nations, which supports goal 8 (Decent work and economic growth). It could secure long-term economic prosperity by providing many job opportunities and raising living standards. Furthermore, enforcing the fishing industry and improving the fishing port infrastructure

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could be categorized under goal 9 of the SDGs (Industry, Innovation, and Infrastructure), highlighting the idea of building resilient infrastructure, supporting innovation that generates employment and wealth, and promoting inclusive and sustainable industrialization. Recently, Egypt has made tremendous progress in supporting sustainable coastal fishing by building new seaports and enhancing the efficiency of existing ports, both of which are critical components of the 2030 Agenda. Which also contains the following; Building and developing seaport infrastructure following international market economics and standards (constructing and refurbishing docks to accommodate new vessels, boosting private sector participation in port development), raising the environmental classification of Egyptian seaports so that they can be converted into green ports, which will help to promote environmental sustainability, and developing Egypt’s Integrated Coastal Zone Management (ICZM) vision, which was established to protect and govern the country’s marine and coastal areas. Following the Egyptian Vision 2030, a series of studies were implemented to investigate the status of Egyptian fishing ports. In 2016, an assessment of coastal fishing ports on the Mediterranean Sea of Egypt was released based on field surveys and stakeholder discussions to figure out existing fishing port issues (Negm et al. 2016). Also, the challenges facing the investigated fishing ports and the opportunities that could be enforced were presented (Sharaan et al. 2016). At the same time, further investigation was considered for the Red Sea fishing ports in 2017 (Sharaan et al. 2017a). The applied questionnaires and their detailed results based on the statistical estimations were released in 2017 for a comprehensive assessment (Sharaan et al. 2017b). The series also included an analysis of the sedimentation issues within the port entrance for one of the investigated fishing ports using numerical simulation (Sharaan et al. 2018). Deterioration of the basic infrastructure, operational and functional facilities, and environmental conditions were the highlighted results that need to be addressed wisely and rationally considering the Egyptian goals and vision for 2030. Therefore, this paper aims to highlight the Japanese experiences and practices for planning and managing fishing ports, which could enhance the Egyptian fishing ports via applying the proper Japanese skills and key factors that could improve the current conditions and promote the environment of the Egyptian fishing ports and develop the fish industry in Egypt, following the Egyptian strategy 2030.

5.2 Case Studies Japan is an island nation in the Pacific Ocean, whose shoreline is 34,000 km long. Japan has constructed and improved approximately 1100 ports and harbors in addition to about 3000 fishing ports through the last one and a half centuries; this makes one fishing port for every approximately 10 km of shoreline. These fishing ports play important roles in the sea and coastal zone (Takezawa 2004). Among the 3000

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Fig. 5.1 Sites of the seven investigated fishing ports in Japan

Japanese fishing ports, 75% are categorized as type I according to Japanese classification (type I is a small-scale fishing port used only by the Japanese fishermen from several adjoining fishing communities and accommodates roughly 100 fishing boats). The investigated fishing ports are Hakazaki and Iioka fishing ports at Chiba prefecture, Kitaahimoura and Miura fishing ports at Kanagawa prefecture, and Shikabe, Kuroiwa, and Kunni at Hokkaido prefecture. Figure 5.1 shows the sites of the investigated Japanese fishing ports during field surveys in Japan.

5.3 Methodology 5.3.1 Data Collection Various measures based on visual observation, discussions, and interviews during the field surveys were applied to collect the essential data for the analysis. Similar approaches were used to examine Scotland’s marine planning (Greenhill et al. 2020). A visual observational tool is useful for qualitative data collection (Lewis and Ritchie 2003). Observation presents the opportunity to analyze behaviors and interactions as they occur and fulfill the quality assurance of the collected data. The steps adopted to collect data via surveying tools and field trips include: • Studying the available released technical reports, papers, and literature respecting the Japanese fishing ports. • Visual observation and discussion about the offered functional facilities via the field visits to the studied fishing ports. • Conducting group interviews with some fisheries institute managers in Japan and discussions about the Japanese fishing ports’ issues and features.

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A visit to the Japanese National Research Institute of Fisheries Engineering (NRIFE, Chiba prefecture, http://nrife.fra.affrc.go.jp/index_e.html) was arranged by the first author. This institute offers engineering solutions for a wide range of problems in fisheries and is working on advanced research for developing the fishing industry according to sustainable seafood supplies to the national market. Furthermore, the port planning department, Yokosuka city office (Kanagawa prefecture, http://www.city.yokosuka.kanagawa.jp.e.rb.hp.transer.com/6620/ index.html) was visited to discuss the division’s role in the planning of Japanese fishing ports and to provide us with different details about the coastal structures for shore protection and incoming plans. Finally, a visit to Alpha Hydraulic Engineering consultants, located in Sapporo, Japan (Hokkaido prefecture, https://ahec.jp/), was undertaken to discuss the consultant activities in Hokkaido prefecture.

5.4 Results and Discussions The featured results for the Japanese practices in planning and managing Japanese fishing ports are investigated. First, the Japanese port managers did their best to provide us with information about the Japanese fishermen, behaviors, fishing port elements, facilities, and applied regulations; this is particularly useful considering that no English documentation covers these domains. No unique guideline is applied across all Japanese fishing ports, i.e., each case is unique in terms of location, weather conditions, soil, geomorphology, meteorological, and oceanographic aspects. The field surveys of three Japanese prefectures refer to the concept of independence and localization decisions. Each prefecture has guidelines, concerns, responsibilities, and duties for fishing port planning, design, and management. However, they are subjected to technical standards for port and harbor facilities (The overseas coastal area development institute of Japan, Ports and Harbors Bureau, Ministry of Land, infrastructure, transport, and Tourism, National Institute for Land and infrastructure management 2009) (The Overseas Coastal Area Development Institute of Japan, Ports and Harbors Bureau 2009), a guide for planning of a fishing port and fishing ground facilities (in the Japanese language), and Law No. 68 of 1998 for prevention of Marine Pollution and Maritime Disaster (Provisions 1998). The purpose of this Decree is to avoid marine pollution and maritime disaster via monitoring the discharge into the ocean of noxious liquid substances, oil, and other wastes from ships and functional facilities, also by securing proper disposal of waste oil using techniques for the removal of the discharged oil, noxious liquid substances, and other wastes. Generally, the investigated Japanese fishing ports are provided by different basic and functional facilitates at the landing and resting quays for fish handling and related activities such as ice factory, auction hall, water supply, slipway facility, etc., which refer to the main strengths’ factors. Figure 5.2 shows functional facilities located at the landing berth in Miura fishing port. On the other hand, it was observed that the landing berths have a slight dual-slope connected to the underground passage/

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open channel/pipe (Fig. 5.3), which facilitates wastewater drainage (resulting from fish handling activities, fish washing, and cleaning) from fish handling hall and fish handling area towards a wastewater tank and to avoid leakage of the wastewater to the seaside which promotes the water quality within the ports. Securing the stability of the breakwater and other facilities in storm surges and other rough sea weather conditions is considered one of the Japanese fishing ports’ main planning and design concepts. Furthermore, it is observed that the main basin

Fig. 5.2 Functional facilities at the landing berth of Miura fishing port, Kanagawa prefecture

Fig. 5.3 Wastewater drainage system at landing berth of Miura fishing port, Kanagawa prefecture

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Fig. 5.4 Layout of Iioka fishing port, Chiba prefecture

of some of the investigated fishing ports in Japan is planned at the rear of the port to keep the boats as safe as possible in the event of storms, as existing in the Iioka fishing port (Fig. 5.4). Also, it was observed that the main breakwater usually has a vertical wall to mitigate the overtopping waves during storms. Since fishing vessels are generally small, they require a calm basin with a wave height of less than 0.5 m. Otherwise, some Japanese fishing ports suffer from water calmness issues; however, wave analysis studies are implemented to increase the calmness ratio in fishing ports. In addition, water quality issues appear in some of the investigated fishing ports considering the water exchange rate, which is affected by weather conditions in summer (the water exchange rate becomes weak in summer, which increases water quality issues in this period). Shikabe fishing port is provided by a pump chamber, where the pump withdraws seawater from the nearshore (water depth = 7.0 m) to the port and transfers the seawater tank. Then convey it to 56 water outlets distributed along with the landing berths for fish and shellfish cleaning and washing purposes (Fig. 5.5). However, many investigated ports are subjected to siltation issues at the entrance respecting littoral drift and sediment transport. The mode of siltation is usually analyzed to detect the probable causes and applicable countermeasures to mitigate the siltation issues and provide a safe environment for the navigation of ships. Occasionally, to prevent the intrusion of sand and damage to adjacent beaches, the construction of an offshore fishing port linked to the shore by a bridge is planned, as was observed in Kunni fishing port, which is considered one of the unique fishing ports, where it is a small fishing port constructed offshore along the sandy beach and connected to the coastline by a bridge (205 m length), to mitigate sand deposition and to shoal at the port entrance (which is located out of the surf zone at depth 7.0 and 400 m offshore distance) and beach corrosion alongside the down-drift of the port. The port was designed to permit littoral drift to transport in the lee side of the port between the port and the shore (Kawaguchi et al. 1994). The hydraulic models and numerical simulations were applied to determine the port’s appropriate layout planning and offshore distance considering the tombolo’s growth (Fig. 5.6).

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Fig. 5.5 Pump chamber, seawater tank, and outlets at Shikabe fishing port, Hokkaido prefecture

Fig. 5.6 Basic and functional facilities at Kunni fishing port, Hokkaido prefecture

Furthermore, the following concepts refer to the Japanese features in planning fishing ports, which could reflect the strengths factors and increase their competitiveness. (a) Some wave-dissipating structures are necessary (pier-open piled, slipway, and revetment) within the port to absorb the wave and decrease the effect of reflected and seiches waves. If all quay walls in the port have a vertical structure, this will lower the calmness rate inside the port due to the generation of stronger reflective waves. So, they prefer to construct the slipway inside the port.

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(b) It is not appropriate to interpose a slipway in a continuous quay wall, as this will divide the service space of the quay wall. (c) It is also necessary that portside roads and port connection roads effectively link the port to trunk roads. (d) Water quality should be considered and checked during the planning process; it is difficult to make modifications pursuant to improving water quality inside the port after construction. Respecting the Japanese fishing ports, it has a unique infrastructure (breakwaters, berths, and facilities). Its design considers the expected disasters, such as storms, hurricanes, and tsunamis, to provide a proper calmness ratio for fishing activities and practices within the fishing ports. Furthermore, Japan has privacy guidelines for planning, designing, and managing fishing ports, including environmental laws. The environmental conditions of the Japanese fishing ports refer to excellent status. However, the variety in water quality among some ports, but generally, they provide different facilities that limit the leakage of wastewater and the treatment process before flushing it to the sea.

5.5 Conclusions Japan has enormous fishing ports that provide massive amounts of fish stocks compared with the relatively poor production of the Mediterranean Sea. The main strengths include providing the main protein food source in high-quality conditions and increasing fishing experiences in both countries. Japanese fishing ports have strong infrastructure, different safe functional and operational facilities, and a commitment to environmental regulation. Difficult working conditions, water calmness issues, and decreasing the number of qualified are major threats in the Japanese fishing ports. Also, weather, rough sea conditions, and lack of young labor reflect some obstacles that face the Japanese fishing ports. Considering the Japanese experiences in planning and managing the fishing ports, the following recommendations and strategies could be considered and applied to enhance the performance of the Egyptian fishing ports: Activate fishing regulations, policies, and laws to achieve sustainable fish sources and emphasize monitoring of fry fish; Cooperation with the neighboring Mediterranean sea’s countries for permission to catch outside regional sea fishing ground; Increasing the salaries of fishermen to encourage and attract further labor; developing fishing fleet and developing the fishing equipment for deep-water fishing; Providing suitable waste disposal facilities and providing separate berth for fuel supply and oil replacement and increasing the fisherman awareness by the environmental issues. Increasing/extending the water area for safer maneuvering; Providing and improving the functional facilities for safe handling, landing, and mooring; Improving the applied traditional management behaviors considering the integrated management concepts.

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Acknowledgements The first author would like to thank Egyptian Ministry of Higher Education (MOHE) for providing the financial support (PhD scholarship) for this research as well as the Egypt-Japan University of Science and Technology (E-JUST) for offering the facility and tools needed to conduct this work. Thanks to managers of the investigated Egyptian fishing ports, Coastal Research Institute, and National Water Research Centre for their technical support. Many thanks to Dr. Nakayama and Dr. Yoshino, Alpha Hydraulic Engineering Consultants, Dr. Nakaizumi, Tokyo University of Marine Science and Technology, and Dr. Ohmura, Head Fisheries Infrastructure Group, National Research Institute of Fisheries Engineering. Special thanks to my Eng. Okamoto, the Japanese tutor, for his great efforts and for assisting me through my field visit to the Japanese ports.

References Frihy O (2001) The necessity of environmental impact assessment (EIA) in implementing coastal projects: lessons learned from the Egyptian Mediterranean coast. Ocean Coast Manage 44(7– 8):489–516. https://doi.org/10.1016/S0964-5691(01)00062-X Greenhill L, Stojanovic TA, Tett P (2020) Does marine planning enable progress towards adaptive governance in marine systems? Lessons from Scotland’s regional marine planning process. Maritime Stud 19(3):299–315. https://doi.org/10.1007/s40152-020-00171-5 Kawaguchi T, Hashimoto O, Mizumoto AK (1994) Construction of offshore fishing port for prevention of coastal erosion. Coast Eng 1197–1211 Lewis J, Ritchie J (2003) Qualitative research practice: a guide for social science students and researchers, p 349 Ligteringen HV (2012) Ports and terminals. Delft Academic Press/VSSD, Delft, The Netherlands Negm AM, Sharaan M, Iskander M (2016) Assessment of Egyptian fishing ports along the coasts of the Nile Delta. In: The Nile Delta. Springer, Cham, pp 471–494. https://doi.org/10.1007/698_ 2016_93 Okafor-Yarwood I (2019) Illegal, unreported and unregulated fishing, and the complexities of the sustainable development goals (SDGs) for countries in the Gulf of Guinea. Mar Policy 99:414– 422. https://doi.org/10.1016/j.marpol.2017.09.016 PIANC (1998) Planning of fishing ports. World Association for Waterborne Transport Infrastructure Provisions CIG (1998) Law relating to the prevention of marine pollution and maritime disaster, p 136 Sciortino JA (2010) Fishing harbour planning, construction and management. Food and Agriculture Organization of the United Nations (FAO), Rome. Available at: http://www.fao.org/docrep/013/ i1883e/i1883e00.htm Sharaan M, Negm A (2017) Life cycle assessment of dredged materials placement strategies: case study, Damietta port, Egypt. Procedia Eng 181:102–108. https://doi.org/10.1016/j.proeng.2017. 02.375 Sharaan M, Negm A, Iskander M, Nadaoka K (2016) Egyptian fishing ports challenges and opportunities case study: Mediterranean Sea ports. Ports 2016:540–549. https://doi.org/10.1061/978 0784479919.055 Sharaan M, Negm A, Iskander M, El-Tarabily M (2017a) Analysis of Egyptian Red sea fishing ports. Int J Eng Technol 117–123. https://doi.org/10.7763/IJET.2017.V9.955 Sharaan M, Negm A, Iskander M, Nadaoka K (2017b) Questionnaire-based assessment of Mediterranean fishing ports, Nile Delta, Egypt. Mar Policy 81:98–108. https://doi.org/10.1016/j.mar pol.2017.03.024 Sharaan M, Ibrahim MG, Iskander M, Masria A, Nadaoka K (2018) Analysis of sedimentation at the fishing harbor entrance: case study of El-Burullus, Egypt. J Coast Conserv 22:1143–1156. https://doi.org/10.1007/s11852-018-0624-y

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Takezawa M et al (2004) Survey of fishermen attitudes in Japan. WIT Trans Ecol Environ 245–254 The Overseas Coastal Area Development Institute of Japan, Ports and Harbors Bureau (2009) Technical standards and commentaries for port and harbor facilities in Japan

Chapter 6

Study of the Influence of Pipeline Sediment on Drainage Capacity Based on SWMM and GSC Coefficients Fuchen Ban, Hong Ai, and Mingxuan Zhang

Abstract Urban drainage network is the infrastructure of urban construction, providing the function of discharging rainwater and sewage. With pipeline deposits, the overflow capacity of pipes can be reduced, while the burden on the pipes themselves increases, leading to sewage overflow and deteriorate the water environment. In order to improve the efficiency of the dredging work, the local Government requires the use of computer models to assist in the work. The SWMM (Storm Water Management Model) is deployed to simulate the sediment scour model, using NSE and GSC coefficients to assess the current level of pipe siltation at all levels, so as to refine the pipes that need to be dredged, thus, the current work is based on the SWMM. Keywords Drainage network · Pipeline sediment · SWMM · Pipeline dredging

6.1 Introduction It is of great practical significance to carry out research on the formation pattern and nature of sediments, so as to control the formation of sediments in pipeline networks and to alleviate urban water pollution (Wu 2020; Geng 2013). Sediments are rich in nutrients and a large number of microorganisms, where, under the action of microorganisms, material transfer between sediments and pollutants occur (Wang et al. 2021), which is transformed in three ways: physical deposition, biotransformation adsorption and biotransformation. Toxic and harmful gases and pipeline corrosion phenomena are produced in pipelines, and rainfall causes problems such as the overflow of check wells as well as insufficient carbon sources to downstream wastewater treatment plants (Li et al. 2022). A visual sediment scour model was established based on SWMM (Storm Water Management Model) to analyze the effect of sediments on the drainage capacity of each type of pipe, simulate and evaluate the drainage capacity of pipes after conventional desilting, and simulate F. Ban · H. Ai (B) · M. Zhang Shenyang Jianzhu University, Shenyang 110168, LN, China e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_6

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labor-cost-saving desilting strategies on this basis, so as to provide a reference for the sedimentation and pollution control of urban drainage networks.

6.2 Research Methods 6.2.1 Model Building The study area is the YSFQ plot in the HB Area of TJ City, which has a low overall design standard relative to the current degree of urban development due to the early construction of the drainage system, which is based on a combined flow system. According to the basic information of drainage pipe design in the study area, a sediment-free drainage system model was established using SWMM, and a sediment scour model was established by converting local geographic data and municipal pipe network data into the .shp format and then .inp files through inpPINS, after which sediment scour curves and Chicago rain patterns were added in SWMM to construct a sediment scour model (Zhang 2020) for the continuous monitoring, so as to study the change in the sediment thickness after 120 min. After the data was imported into the SWMM model, the errors of each piece of data were within a controllable range, meanwhile the surface runoff was 0.02%, the flow routing was 0.14%, and quality routing was 0. The errors were small and the model could be used normally. In Fig. 6.1, the model contains a total of 52 sub-confluence areas, 55 pipe sections, 63 inspection ports and 4 drainage ports, with the sub-confluence area in 0.02–2.29 hm2 divided into three levels according to the size of the pipe diameter, including 17 main pipes (D = 800–1200 mm), 20 trunk pipes (D = 500–800 mm) and 18 branch pipes (D = 200–500 mm), which are prepared for the study of pipeline flow variations.

6.2.2 Relationship Between Flow Rate and Sediment Volume Through investigation, it has been found that the drainage system pipelines are affected by sediment deposition to varying degrees, with 78% of pipeline sections showing significant sediment deposits and 16% showing a small amount of sediment. Studies have shown that drainage pipelines generate between 30 and 500 g of sediment each day, and that combined systems produce 20% more sediment compared to split pipe systems with the same diameter. For the purpose of this research, split pipe systems will be converted to combined systems to facilitate comparison. Furthermore, different types of drainage pipelines have been found to have varying sediment thicknesses, so this simulation study will classify pipeline sections into three categories: branch pipe, trunk pipe, and main trunk pipe. Additionally, the sediments in pipelines with different diameters within the study area will be examined.

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Fig. 6.1 Sediment scouring model

The flow velocity is the main reason to determine the degree of siltation; when the flow velocity is lower than the sediment accumulation rate, the sediments lead to deposition phenomenon and pipeline siltation will become serious; when it is greater than the sediment deposition rate, the sediments will migrate downstream with water flow and can alleviate pipeline siltation (Zhang et al. 2020). By controlling the scouring of sediments in the pipes based on the flow velocity at each moment, the degree of pipe siltation is divided into three levels according to the flow velocity, which are very-easy-to-siltation pipes (Level 1), easy-to-siltation pipes (Level 2), and not-easy-to-siltation pipes (Level 3), see Table 6.1. Capacity, and the effect of sediments on the drainage capacity of the pipe network after desilting is compared and analyzed (Fu et al. 2018). Nash–Sutcliffe (NSE) efficiency coefficients are often used as efficiency evaluation indicators for hydrologic models, which can also be used in the evaluation of other model simulation results. Based on the NSE coefficients, it is optimized as a calculation equation for each level of pipe section (Eq. 6.1), in which the closer the coefficient is to 1, the better overwater capacity a pipe has, and the closer it is to 0,the more seriously is the pipe affected by sediments. N N SE = 1 −

i=1 (vmax − vmin ) N 2 i=1 v

2

(6.1)

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Table 6.1 Siltation control table for each level Very-easy-to-siltation pipes (Level 1) (m/s)

Easy-to-siltation pipes (Level 2) (m/s)

not-easy-to-siltation pipes (Level 3) (m/s)

Branch pipe (D = 200–500 mm)

< 0.1

0.1–0.2

> 0.2

Trunk pipe (D = 500–800 mm)

< 0.15

0.15–0.25

> 0.25

Main trunk pipe (D = 800–1200 mm)

< 0.4

0.4–0.6

> 0.6

where NSE vmax vmin v

Coefficient evaluation factor, dimensionless quantity; Hourly maximum flow rate,m/s; Hourly minimum flow rate, m/s; Hourly average flow rate, m/s.

Sediment thickness can be calculated based on the pipeline network siltation evaluation coefficient (hereinafter referred to as GSC) (Eq. 6.2) to study pipeline siltation at all levels, and this coefficient is used as an indicator to evaluate the degree of pipeline siltation in the system, the closer it is to 1, the greater the intensity of pipeline siltation will be, and conversely, the stronger the pipeline overflow capacity will be. In this study, the pipeline is controlled with a coefficient of greater than 0.65 as that should be dredged.  i P G SC =  scd Pid

(6.2)

where GSC Evaluation coefficient of siltation of the whole-area pipe network, dimensionless quantity; i Pipe section number; Piscd Siltation depth of pipe i, m; Pid Diameter of the pipe, m.

6.3 Applications 6.3.1 Flow Rate Analysis During the 120 min monitoring (Fig. 6.2), the branch pipe overflow section is smaller and the flow velocity changes more, which make the probability of sediment migration and deposition increase, the sediment thickness decreases at the end of the

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Fig. 6.2 Partial pipeline node inflow diagram

rainfall, and the branch pipe sediments are mainly migrated; some trunk pipes need to receive the sediments migrated from the pipes, the sediments decrease by 2.69% at the end of the rainfall, and the sediments migrate with the rainfall flushing; the diameter of the main pipe is larger, where the hydraulic conditions are better than those of the branch and trunk pipes, making the sediments have less impact on the pipe overflow capacity. Larger and better hydraulic conditions than branch pipes and trunk pipes, make the sediment have less impact on the pipeline overwater capacity, because the trunk pipe is generally at the end of the system, whose daily maintenance is more difficult, thus, it is recommended to reduce the emptying of this type of pipe section, enhancing the pipeline system less (Fig. 6.3).

6.3.2 Siltation Analysis By studying the flow data obtained through the SWMM model, it was found that the effect of sediments on the pipe section was branch (0.64) > trunk (0.58) > total trunk (0.55). After desilting the pipes with GCS > 0.65, the drainage capacity of the system can be improved by 35.23%; the drainage capacity of the main trunk pipe in this system is normal, excessive desilting should be avoided to cause insufficient carbon sources into the downstream sewage plants, and in the branch and trunk pipes

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Fig. 6.3 Different pipes relationship diagrams. a Branch pipe relationship diagram. b Trunk pipe relationship diagram. c Main trunk pipe relationship diagram

with GCS > 0.65, basically, the drainage capacity can be improved by 24.99% with desilting focused at the catchment and the inflection point, although the improvement is slightly reduced, the desilting effect is good (Table 6.2).

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Pipeline type

Siltation grade

NSE

Branch pipe

Level 1

0.8

0.87

Level 2

0.26

0.67

Level 3

0.96

0.38

Level 1

0.71

0.76

Level 2

0.91

0.64

Level 3

0.94

0.35

Level 1

0.99

0.72

Level 2

0.99

0.63

Level 3

0.76

0.31

Trunk pipe

Main trunk pipe

GSC

6.4 Conclusion In this study, the SWMM model was used to evaluate the dredging in a region, and the pipelines were evaluated according to the GSC mathematical model. The GSC mathematical model, which can be used to alleviate the sedimentation peak during the outbreak period to a certain extent, ensuring sufficient nutrients into the wastewater plants and a good desilting effect. The pipes most severely affected, by sedimentation in this system are the 200-500 mm branch pipes (NSE = 0.26, GSC = 0.65), based on GSC coefficients more precisely. By conducting desilting experiments on pipes with GCS > 0.65, the sediment thickness of the desilted pipes was counted and imported into the original SWMM model (surface runoff = 0.02%, flow routing = 0.08%, quality routing = 0), meanwhile the branch and trunk pipes could be improved by 44.4% and 30.56% respectively in terms of drainage capacity. Acknowledgements I would like to thank the teachers from the school and the laboratory for their help in my research and writing. I would like to thank the Liaoning Provincial Department of Education in 2021 (LJKZ0576) and the Social Governance Science and Technology Special Project of the Shenyang Science and Technology Plan (21-108-9-33) for our research financial support.

References Fu BW, Jin PK, Shi S (2018) Study on sediment characteristics in Xi’an city sewage network. China Water Supply Drainage 34:119–122 Geng LX (2013) Experimental study of sediment scour model for combined flow system pipeline. Wuhan University of Technology, Wuhan Li JR, Zhou Y, Li Z (2022) Simulation analysis of the effect of pipeline silting on drainage capacity based on SWMM. China Water Supply Drainage 38:118–125 Wang J, Liu GH, Qi L (2021) Progress in the study of material transfer and transformation between sediment and sewage in urban drainage pipes. China Water Supply Drainage 37:34–44

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Wu YF (2020) Study on the selection and optimization of the renovation scheme of the combined flow system drainage system in the old city. Hunan University, Hunan Zhang Q, Yu J, Li TB (2020) Study on the initial scouring effect of stormwater pipe sediment pollution and initial stormwater volume. Water Supply Drainage 56:119–124 Zhang QW (2020) Research on SWMM-based drainage pipe sediment scour model and initial rainwater interception volume calculation method. Hunan University, Hunan

Chapter 7 87 Sr/86 Sr

Tracer for the Formation and Evolution of Deep Underground Brines in Sedimentary Basins Hang Ning, Wanjun Jiang, Futian Liu, Jing Zhang, Sheming Chen, and Zhuo Zhang

Abstract The basic research on the source and evolution of deep underground brines is helpful to deepen understanding for the formation of natural hydrosphere, and also of great significance to evaluate the diagenetic history assessment of basins (such as mineralization, crustal circulation, fluid flow and migration) and reservoir yield management. In recent years, the combination of traditional element geochemistry and isotope techniques, especially the 87 Sr/86 Sr isotope, has made the research on the source, formation and evolution of deep underground brines in basins gradually becoming an international hot topic. In this paper, the research progress of application and development of 87 Sr/86 Sr tracer for the source and formation of deep underground brines was summarized and commented. And the numerical ranges of different stable isotopes in deep underground brines and other natural reservoirs are summarized. Until now, the studies indicated that the 87 Sr/86 Sr values in deep underground brines mainly ranged from 0.70810 to 0.72413. This paper is helpful to deepen the understanding of strontium isotope and provide a reference for research on the formation and evolution of deep underground brines in in sedimentary basins. Keywords 87 Sr/86 Sr isotope · Source information · Formation and evolution · Deep underground brines · Sedimentary basins

H. Ning (B) · W. Jiang · F. Liu · J. Zhang · S. Chen · Z. Zhang Tianjin Center, China Geological Survey, Tianjin 300170, China e-mail: [email protected] North China Center for Geoscience Innovation, China Geological Survey, Tianjin 300170, China Tianjin Key Laboratory of Coast Geological Processes and Environmental Safety, Tianjin 300170, China © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_7

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7.1 Introduction Deep underground brine water, also known as “formation water”, refers to the groundwater body with a total solubility of more than 100 g/L, which mainly occurs in the deep of sedimentary basins and has a huge amount of resources (Yu et al. 2019). Deep underground brine with huge resources has been found in the Illinois Basin in the United States, the Paris Basin in France, the Western Canada Basin, the Jianghan Basin in China, etc. These deep groundwater usually carries or is rich in trace or metallic elements such as potassium, boron, lithium, strontium, bromine and iodine (Jiang et al. 2022a; Chan et al. 2002; Tan et al. 2011; Bagheri et al. 2014).With the water–rock interaction between the deep underground brine and the rocks in the strata, the migration and transformation in the groundwater flow field ultimately gather and form mineralization. Therefore, the ratio of 87 Sr/86 Sr in water bodies and mineral rocks can not only be used to trace the source of water and salt, analyze the evolution law of groundwater circulation, but also reveal the formation mechanism and occurrence law of minerals in the sedimentary basin, providing valuable scientific basis for the exploration, development and utilization of salt, hydrocarbon and metal deposit resources (Hanor and Mcintosh 2006, 2007). In recent years, the combination of traditional element geochemistry and isotope techniques, such as the H, O and 87 Sr/86 Sr isotopes, has provided the understanding of groundwater circulation and evolution (Jiang et al. 2022b; Miao et al. 2022). Generally, weathering in nature causes strontium in mineral rocks to be released into natural waters. The variation of 87 Sr/86 Sr ratio reflects the composition of Sr isotopes from different mineral sources because of the specific 87 Sr/86 Sr ratios in different mineral rocks and few fractionation process for Sr isotope (Négrel 1999; Négrel et al. 2001; Barbieri and Morotti 2003). Groundwater or surface water is usually used to dissolve the Sr and obtain different 87 Sr/86 Sr ratios when it flows through rock minerals in different geological environments. The 87 Sr/86 Sr ratio in different waters mainly depends on the 87 Sr/86 Sr values of surrounding rock minerals, and it can be utilized to reflect the different sources of water and the water–rock interactions with different rock minerals (Gaillardet et al. 1999; Ma et al. 2015). Therefore, the 87 Sr/86 Sr ratio in different waters is an ideal tracer for water sources and flow paths (Ma et al. 2015, 2008). The chemical and physical properties of Sr2+ and Ca2+ are similar in different geological bodies, with similar ionic radius and the same charge. Therefore, Sr2+ can replace Ca2+ in the mineral crystal lattice and is often found in calcium and potassiumrich mineral rocks with a lower ratio of 87 Sr/86 Sr such as carbonate, plagioclase, gypsum, amphibole, etc. However, in addition to the above-mentioned rock minerals, the mica, anorthite and potassium feldspar in the siliceous clastic rocks and the potassium salts in evaporite minerals in sedimentary basins are rich in radiogenic 87 Sr. Strontium can also continuously enter waters with the dissolution of these minerals resulting a high 87 Sr/86 Sr ratio in waters (Russell et al. 1988; Chaudhuri and Clauer 1993; Barnaby et al. 2004).

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However, previous studies have found that Sr isotope, unlike hydrogen and oxygen stable isotopes, produce almost few significant fractionation during physical, chemical and biological reactions, and are mainly controlled by the dissolution of minerals and the strength of water–rock interaction (Négrel 1999; Négrel et al. 2001; Chaudhuri and Clauer 1993). In recent years, the 87 Sr/86 Sr ratio in waters and mineral rocks has been widely employed to trace the source of water and salt (Barnaby et al. 2004; Dogramaci and Herczeg 2002; Négrel 2006; Klaus et al. 2007; Min et al. 2007; Vengosh et al. 2009, 2007; Fan et al. 2018), the circulation and evolution of groundwater (Barnaby et al. 2004; Han and Liu 2004; Tan et al. 2011), the identification of water–rock interaction strength (Gaillardet et al. 1999; Millot et al. 2003; Fan et al. 2010; Chapman et al. 2013; Douglas et al. 2013; Brennan et al. 2014; Capo et al. 2014; Stewart et al. 2015).

7.2 The Application of Sr Isotope in Deep Underground Brines The variation of 87 Sr/86 Sr ratio mainly reflects the change of material source (Barbieri and Morotti 2003), therefore, the 87 Sr/86 Sr ratio has been widely utilized by scholars as one of the effective methods to identify the water–rock interactions and hydrogeochemical evolution processes of groundwater (Barnaby et al. 2004; Han and Liu 2004; Edmunds et al. 2006; Raiber et al. 2009; Qu et al. 2018). Additionally, as early as 1990s, Chaudhuri proposed that the 87 Sr/86 Sr ratios can be employed to provide more information about the sources and hydrochemical evolution history of deep underground brine in basin (Chaudhuri 1978). After that, the 87 Sr/86 Sr ratio was widely employed to identify and track the sources, migration, mixing of deep underground brines and water–rock interactions with different mineral rocks due to the stability of Sr isotope (Barbieri and Morotti 2003; Tan et al. 2011; Birkle et al. 2009; Dotsika et al. 2010; Lüders et al. 2010; Meredith et al. 2013; Bagheri et al. 2014). The range of 87 Sr/86 Sr ratios in different mineral rocks or waters in nature is shown in the Fig. 7.1. The 87 Sr/86 Sr ratio of the deep underground brines in large sedimentary basins mainly ranged from 0.70810 to 0.72413 according to the relevant studies carried out by many scholars in the world. And the variation of 87 Sr/ 86 Sr ratio in deep underground brines was mostly due to the entry of radiogenic 87 Sr under more prolonged water–rock reactions or affected by the mixed effect of different water types. For example, the 87 Sr/86 Sr ratio of deep underground brines in the Kangan gasfield, Iran was 0.7119 (Bagheri et al. 2014), is similar to deep underground brines from other oil and gas fields, such as Palm Valley, America with 87 Sr/86 Sr ratios from 0.7140 to 0.7155 (Andrew et al. 2000) and the North German Basin were from 0.7145 to 0.7158 (Lüders et al. 2010). In oil and gas fields of the North Appalachian Basin, North American, deep underground brines has typical radiogenic Sr enrichment characteristics with high 87 Sr/86 Sr values from 0.71000 to 0.72200 (Harkness et al.

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ratio characteristics in different water types or geological bodies in nature

2017), with Marcellus deep underground brines being less radiogenic Sr with from 0.71000 to 0.71212 (Chapman et al. 2013; Capo et al. 2014; Warner et al. 2014) than Upper Devonian deep underground brines (from 0.71580 to 0.72200) (Chapman et al. 2013; Warner et al. 2014). In Europe, the high 87 Sr/86 Sr ratios of the Oeillal spring water in the northern Pyrenean thrust region suggested the deep water circulation has been influenced by the saline water in the salt clay Triassic sediments or fractured basement, and undergone secondary modification by water–rock interaction(Khaska et al. 2015). The release of radiogenic Sr from K-rich minerals in the clay or granitic basement was the key factor that increased the ratio of 87 Sr/86 Sr in deep underground brines (Khaska et al. 2015). At present, the separation and testing means of strontium isotopes have been very mature. After the sample is enriched and dried by cation exchange resin, the interference of impurity elements and homoectopic elements on the mass spectrum is removed, and the Thermo-Finnigan Neptune Plus type high resolution multireception inductively coupled plasma mass spectrometer is used for testing. Its test accuracy is determined by the instrument international standard sample NIST SRM 987 87 Sr/86 Sr = 0.710253 ± 0.000006 and geological standard sample BCR-2 (87 Sr/ 86 Sr = 0.705029 ± 0.000009) to check, 87 Sr/86 Sr measurement error is less than 0.00002. Specific experimental procedures are as follows: (1) Chemical pretreatment operation for strontium isotope test: Take 1–100 ml of water sample and evaporate it to dryness in cleaned polytetrafluoroethylene beaker. Add 1 ml concentrated HCl, and then heat it in an electric heating plate at 130 °C to dissolve the sample. After dissolution, open the lid and evaporate it to dryness at 100 °C. After cooling, add 1 ml of 2.5N HCl to a constant volume

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and prepare for chemical purification. The chemical purification of strontium isotopes was performed by passing a solution containing strontium through a resin column. Strontium isotope chemical purification was performed by passing a strontium-containing solution through a column containing a resin, AG 50WX12 resin (200–400 mesh, approximately 12 cm filling length) produced by Bio-Rad, followed by 20 ml 6N HCl, 5 ml MQ water, and 4 ml 2.5N HCl cleaning resin. The sample containing 1 ml 2.5N HCl was centrifuged and the supernatant was slowly added into the resin-filled column. Rinse the matrix elements with 1 ml of 2.5N HCl and 15 ml of 4N HCl. After sequentially adding 7 ml of 4N HCl and 4 ml of 6N HCl to collect strontium, add 0.1 ml of concentrated HNO3 to the collected strontium rich solution and evaporate to dryness. Finally, add 1 ml of 3% HNO3 to a constant volume. (2) Strontium isotope testing operation: Thermo-Finnigan Neptune Plus high resolution multi-receive inductively coupled Plasma Mass Spectrometer (MC-ICPMS) was used for detection. Firstly, an appropriate amount of strontium solution was extracted from the sample after chemical purification and constant volume in 7 ml tube, and then diluted into a solution with a concentration close to 150 ppb. After shaking, the solution was ready for machine test. The quality discrimination effect of the instruments was corrected using sample-standard bracketing (SSB). The international standard NIST SRM 987 was tested once every 4 samples to monitor the stability of the mass spectrometry test in real time. The NIST SRM 987 87Sr/86Sr ratio measured during sample analysis was 0.710253 ± 0.000006, which should be consistent with the long-term laboratory analysis result of 0.71027 ± 0.00002 (2SD, N = 61). At the same time, it is consistent with the international recommended value 87Sr/86Sr = 0.71034 ± 0.00026. In many large sedimentary basins in China, strontium isotopes were also frequently employed to identify the source and evolution of deep underground brines. The 87 Sr/86 Sr ratios of deep underground brines from Fuling Gasfield in the Sichuan Basin, China were from 0.723966 to 0.724132 (Huang et al. 2019), much higher than the Silurian seawater (from 0.7077 to 0.7088). And it was also higher than that of produced water in other conventional oil or gas field in Sichuan Basin (0.708102– 0.715239), but reasonably lower than the 87 Sr/86 Sr ratios of massive parent shale, from 0.740246 to 0.740248 (Ni et al. 2010). The chemical and isotopic data indicated that the deep underground brines in the Sichuan Basin originated from seawater evaporation in different periods, and has undergone a series of later transformations of water-rock interaction (Ni et al. 2010). The 87 Sr/86 Sr ratios of deep underground brines from Paleozoic strata in the central Tarim Basin were from 0.71026 to 0.71290, indicating that the higher 87 Sr/86 Sr ratios were the result of radiogenic Sr from water-rock interaction (Cai et al. 2001). In addition, the main controlling factor for the 87 Sr/86 Sr ratios was the mixing of 87 Sr-enriched basinal shale water and 87 Sr-depleted Cambrian/Ordovician depositional water. And there was a mixture of deep underground brines and meteoric waters (Cai et al. 2001). However, in the Lunnan Ordovician paleokarst reservoir in the northern Tarim Basin, the mixing trend

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of 87 Sr/86 Sr ratios (from 0.709801 to 0.711628) provided further evidence that the deep underground brines in the northern Tarim Basin were derived from a mixture of meteoric waters and evaporated seawater (Chen et al. 2013). The high 87 Sr/86 Sr ratios were mainly related to the water-rock interactions with radiogenic minerals, such as micas and K-feldspars in siliciclastic rocks and sylvite in evaporite minerals (Russell et al. 1988; Chaudhuri and Clauer 1993; Barnaby et al. 2004). Similar to the above basins, the 87 Sr/86Sr ratios of deep underground brines from oilfields in the western Qaidam Basin range between 0.711163 and 0.712199 with the characteristics of a relative medium and stable 87 Sr/86 Sr ratios and a large variation of Sr concentration, suggesting that the deep underground brines underwent secondary modification by water-rock interactions (Tan et al. 2011; Fan et al. 2010).

7.3 Conclusions In recent years, the research on source, formation and evolution of deep underground brines in large sedimentary basins based on traditional element geochemistry and isotopic techniques has gradually become a hot topic in the world. The research progress of application and development of 87 Sr/86 Sr tracer for in the source and formation of deep underground brines in large sedimentary basins was summarized and commented. The numerical ranges of Sr stable isotopes in deep underground brines and other natural reservoirs are summarized. Until now, the studies indicated that the 87 Sr/86 Sr values of deep underground brines ranged from 0.70810 to 0.72413. And the variation of 87 Sr/86 Sr ratio in deep underground brines was mostly due to the entry of radiogenic 87 Sr under more prolonged water–rock reactions or affected by the mixed effect of different water types. Funding This work was financially supported by grants from the National Natural Science Foundation of China (42302299) and the China Geological Survey Program (DD20230426, DD20230431).

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Chapter 8

Motion of the Thermal in Static Thermal-Stratified Water Bo Chen

Abstract For control and treatment of sudden pollution accidents in thermalstratified reservoirs, the movement of thermals in the static thermal-stratified water was studied. According to the experimental observation, the motion of thermals in different temperature profile water bodies was significantly different. The horizontal diffusion of thermal was damped in the linear stratified water. If the thermocline existed in stratified water, the thermal would be retarded at the thermocline. Rayleigh–Taylor instability or Double-Diffusion Convection may occur at the bottom of the damped thermal due to the difference of matter concentration and temperature between the thermal and ambient water. Thus, the finger-shaped intrusion emerged; and it would affect the horizontal spread of thermal. By combining experimental data with the dimensional analysis, the relationship between the vertical velocity of thermal U and the thermal forward position Z f , the buoyancy B, the buoyancy frequency N was deduced. Keywords Thermal · Thermal-stratification · Settling velocity · Finger-shaped intrusion

8.1 Introduction With the rapid development of China’s economy, the situation of environmental pollution is serious. Through statistics of unexpected pollution incidents, it is found that water pollution incidents have become the main emergency environmental pollution incidents in China (Han et al. 2010). Many reservoirs in China are large and deep, and they often have water temperature stratification after impoundment, which makes reservoirs have different water temperature stratification structure from rivers (Deng B. Chen (B) School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha 410114, China e-mail: [email protected] Engineering and Technical Center of Hunan Provincial Environmental Protection for River-Lake Dredging Pollution Control, Changsha 410114, China © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_8

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2003). In order to deal with the environmental problems caused by water pollution incident such as the Xin’anjiang reservoir phenol leakage and the Gulf of Mexico oil spill, it is necessary to predict the pollution situation and provide decision support for accident treatment to control the pollutant diffusion. All of these need to accurately grasp the movement of pollutants in the thermal-stratified water. In many water pollution incidents, contaminants are finite parcels of liquid with larger density. Because of negative buoyancy, they sink as thermals. Scorer (1957) studied isolated masses of buoyant fluid which released in a water tank; and discovered that thermals move in an enveloping cone of fixed angle in stagnant ambient fluid by entraining the ambient fluid to increase its size. Li and Ma (2003) also obtained similar results through the experimental observation and the three-dimensional large eddy simulation (LES). Tarshish et al. (2018) studied the movement of turbulent hot air thermals by direct numerical simulations. It was found that thermals were ellipsoids when they rise, and the buoyancy of thermals in the accelerating ascending section is related to the aspect ratio of the ellipsoid. Lai et al. (2015) investigated the behavior of thermal in a quiescent ambient. Results showed that the spreading of the thermal decreased with the initial aspect ratio increased. Bush et al. (2003) examined the settling of particles released into both homogeneous and stratified ambientes; and the particle cloud formed of a turbulent thermal. In the homogeneous ambient, the cloud generated by a total buoyancy excess; and in a stratified environment, the movement of the cloud was related to the buoyancy frequency N. The settling of thermals in thermal-stratified water bodies is mainly affected by buoyancy. With different water temperature structures, buoyancy varieties are very different, which has a great influence on the thermal’s movement. In this paper, laboratory experiments were conducted to study the movement of thermals in static thermal-stratified water bodies, which provided the basis for pollutant diffusion prediction in reservoirs and lakes.

8.2 Experimental Set-Up The experimental apparatus was illustrated in Fig. 8.1. Two horizontal barriers were placed in the middle to separate two layers. Initially, the cold water was deposited into the lower part of the tank; after closed barriers, the warm water was introduced in the upper part. After barriers were withdrawn, the thermal stratified environment was obtained. The electrothermal coupling thermometer was used to measure the vertical temperature profile. As showed in Fig. 8.2, the stratified structure could maintain within 50 min. Each experimental runs was usually less than 10 min, so the heat loss was neglected. The simulated pollutant used in the experiment was a mixture of dye and sodium chloride solution. Simulated pollutants were released on the surface of the water body in three ways. The test group R1 used a bottomless cylinder (Fig. 8.3a) filled with screen netting. During the experiment, placed the cylinder into the water, and poured 5 ml pollutant inside, lifted the cylinder to form the thermal. The test group

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Fig. 8.1 A sketch of the experimental tank

Fig. 8.2 Temperature profile variation at different elapsed time

R2 used a hose to release pollutant (Fig. 8.3b); the pollutant (0.4 ml) was stored in one end and the other end was sealed with clip. During the experiment, one end of the pollutant was placed above the water surface for 5 cm, then released pollutant by opening the clip. The release method of the test group R3 was the same as that of R2 (Fig. 8.3c), but its release outlet was slightly lower than the water surface, and pollutant volume was 0.25 ml. In the experiment, the camera was used to capture the movement of thermal, and required data were obtained by analysing experimental images. The image analysis method was as follows. When the thermal settling, its shape was similar to ellipsoid (Fig. 8.4). That was the same as numerical simulation result of Tarshish et al. (2018). It could be considered that the thermal was an ellipsoid whose horizontal axes

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Fig. 8.3 Release methods of pollutant

were both w and the vertical axis was h. According to Beer-Lambert law, the brightness difference between thermal image and original background was correlated with pollutant concentration, then qualitatively analysed the concentration distribution (Landeau et al. 2014). Comparing each pixel of the experimental image and the original background image to obtain the brightness change caused by dye. Using 50% of the maximum brightness change value inside the thermal as the threshold to eliminate noises (isolated brightness change pixels), and then use 20% of the maximum brightness change value as the threshold to outline the thermal boundary. After processed each frame image, the brightness change value was respectively accumulated vertically and horizontally, and arranged in chronological order to obtain a diachronic change process, as shown in Fig. 8.5. The width w and height h of the thermal were calculated Fig. 8.4 Diagram of vertical movement of thermal

8 Motion of the Thermal in Static Thermal-Stratified Water

t=0s

t=5s

t=10s

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(a)

(b)

(c) Fig. 8.5 The growth of thermal for a typical experiment. a Original experiment image. b Vertical accumulating concentration duration diagram of the growing thermal. c Horizontal accumulating concentration duration diagram of the growing thermal

according to the boundary position, and the barycentre of thermal was determined by the concentration distribution. The non-uniformity of the three-dimensional motion of the thermal caused the aspect ratio to be greatly different at different stages of sinking. The thermal did not maintain a similar shape when it settling. Therefore, the settling velocity of the thermal U was calculated according to the position changing of the barycentre of thermal.

8.3 Experimental Results and Discussions According to experimental observations, there were significant differences in the movement of thermal in static water with different stratified circumstances (Fig. 8.6). When the difference of water temperature between upper and lower layers was small,

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the buoyancy effect caused by the temperature gradient was weak; and the disturbance caused by barriers opening would propagate vertically, resulting in a nearly linear stratified structure, as shown in Fig. 8.7a. In this case, the motion of thermal (Fig. 8.6b) was similar to that in the uniform case (Fig. 8.6a), nonetheless, the settling velocity was less than that of the latter. Whereas, the lateral diffusion was also influenced by the baroclinic condition in the linear stratified water. If the temperature difference between upper and lower parts was increased, the water body could be divided into three layers. The uniform upper and lower layers with different temperatures, and the thermocline with linear distribution of intermediate temperatures, as shown in Fig. 8.7b. In this case, the thermal would be held by buoyancy when it settled to the thermocline. Due to the uneven concentration inside the thermal, the light part (density less than the lower water) would stagnate in the thermocline and continue to diffuse along the transverse direction; the dense part (density greater than the lower water) would produce larger finger-like droplets due to Rayleigh–Taylor instability and invaded the lower water body, as shown in Fig. 8.6c. This finger-like invasion was slow and stopped when it reached a layer of water close to its density.

Fig. 8.6 Typical examples of thermals in various stratification conditions. a Uniform. b Weak stratification. c Moderate stratification. d Strong stratification

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Fig. 8.7 Typical examples of temperature profiles. a Weak stratification. b Moderate stratification. c Strong stratification

Continue increasing the temperature difference between the upper and lower layers, the thickness of thermocline would become very small. In this case, the temperature profile could be considered as a staircase distribution, as shown in Fig. 8.7c. Due to the strong buoyancy effect, the thermal would be blocked in the upper thermocline. As the interaction of temperature gradient (hotter at the top) and concentration gradient (saltier at the top), double-diffusion convection occurred (Batchelor and Moffatt 2000); and a large number of small finger-shaped convective droplets appeared at bottom of the thermal, as shown in Fig. 8.6d. After the small finger droplets left the thermal, they intruded into the lower layer at a very fast rate. Chen et al. (2010) measured the size and intrusion of the above-mentioned finger droplets (moderate stratification runs and strong stratification runs), and considered that the intrusion amount of finger droplets was about 5–20% of the total pollutant amount, also the width of droplets was greater than the double-diffusion salt finger. Apparently, the finger droplets measured by Chen were produced by double-diffusion convection and include the droplets produced by Rayleigh–Taylor instability in moderate stratification. The vertical motion of the thermal was associated with buoyancy, and its value was B=g

m tracer V

− ρ0 + ρ1 V ρ0

where ρ 0 was the average density of the ambient water at the horizontal position of the thermal; ρ 1 was the density of the upper layer of water; mtracer was the dry mass of the simulated pollutant; and V was the volume of the thermal (If the thermal was assumed to be an ellipsoid, the length of both horizontal axes was w, The vertical axis had a length h and its volume was V = 4/3πw2 h). The vertical movement of

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the thermal was also affected by temperature stratification. The vertical velocity of thermal at different depths could be considered as a function of buoyancy B, buoyancy frequency N and thermal front position Zf , ) ( U = f B, N , Z f √ where N = − ρg0 · ∂ρ , and Z f value was shown in Fig. 8.4. The vertical velocity of ∂z thermal U in stratified water could be obtained by dimensional analysis, ( U = c1

B N · Z 3f

)(

B2 N 4 · Z 8f

)c2 + c3

(8.1)

where c1 , c2 and c3 were constants. For uniform water, the vertical velocity of thermal was ( 1) B2 C = c4 (8.2) + c5 Zf where c4 and c5 were constants. According to the data collected from the experiment, the constant coefficients of each group of experiments were calculated by Xu’s method (Xu and Ren 2004). The results of stratified cases were shown in Fig. 8.8, and the results of uniform cases were shown in Fig. 8.9. Three different ways of releasing simulated pollutants (Fig. 8.3) were used in experiments, and the amount of pollutants was different. Meanwhile, the movement of thermal in different ambient water bodies was quite different (Fig. 8.6). In order to understand the vertical movement of thermal under diverse conditions, it was necessary to analyse the constant coefficients in the vertical velocity formula separately. According to Figs. 8.8a and 8.9a, the coefficients c1 and c4 , which were coefficients of the first term of (8.1) and (8.2), obtained from R2 runs were obviously different from those of other release methods. The differentiation was exhibited that the R2 runs used 5 cm above the water surface to release simulated pollutants, causing a large initial momentum to affect the vertical movement of thermal. However, the coefficient c2, which was the exponent of (8.1) for stratified experiments, had little change in different release methods and temperature profiles; it was about −0.2. Otherwise, the values of c3 and c5 (zero-order coefficients in (8.1) and (8.2)) were not affected by the release method or the stratification condition, but the values were relatively discrete. The c1 and c3 in (8.1) and c4 and c5 in (8.2) were related to the initial momentum and the position of virtual origin O (as shown in Fig. 8.4, which reflected the releasing position and quantity of the simulated pollutant). There were some differences in different situations. The exponent c2 in (8.1) reflected the relationship between the physical quantities and was less affected by the initial state. In order to eliminate the influence of the inconsistency of the initial state, the virtual origin O of thermal was set at Z 0 (Fig. 8.4), the initial velocity was U 0 .

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Fig. 8.8 Violin plots (Kabacoff 2015) of constant coefficients for the formula of the settling velocity of thermal with different release methods (R1, R2 and R3) or in various stratification conditions (Weak stratification, Moderate stratification and Strong stratification). a c1 . b c2 . c c3

Fig. 8.9 Violin plots of constant coefficients for the formula of the settling velocity of thermal with different release methods (R1, R2 and R3) in uniform water body. a c4 . b c5

Substituting (8.1) and (8.2) to obtain the vertical velocity of the thermal was ( U = c6 for stratified cases, and

B

)3 ( N Z f + Z0

)(

B2

( )8 N 4 Z f + Z0

)c2 + U0

(8.3)

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Fig. 8.10 Violin plots of constant coefficient c6 Fig. 8.11 Violin plots of constant coefficient c7

( U = c7

1

B2 Z f + Z0

) + U0

(8.4)

for uniform cases. Constant coefficients in (8.3) and (8.4) were recalculated. The results of stratified runs were shown in Fig. 8.10 and uniform runs in Fig. 8.11. In the stratified cases, the constant coefficient c6 was about 0.5, which was not affected by the release method and temperature profile. The value of constant coefficient c7 in (8.4) was about 1.0, which was also not affected by the release method. Substituting the constant coefficient, the vertical velocity of thermal, which in stratified ambient water body, could obtained 1 U= 2

(

)(

B

)3 ( N Z f + Z0

B2

( )8 N 4 Z f + Z0

)− 15 + U0

(8.5)

and in uniform water body, the vertical velocity of thermal was ( U=

1

B2 Z f + Z0

) + U0

(8.6)

; The buoyancy B of the thermal in uniform water body had fixed value g m tracer ρ0 thus the settling velocity of thermal can be inversely proportional to the thermal front

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position Zf by (8.6), which was consistent with the results of Scorer (1957) and Ma (Li and Ma 2003). An interesting phenomenon was also noted in the experiment. When the thermal was trapped on the stratified interface, the vertical size of the thermal was compressed; and its internal concentration was much larger than the uniform cases. Depending on the original theory of environmental fluid mechanics, the lateral expansion rate v should be increased. Nevertheless the lateral expansion rate did not increase, but slowed down after the finger-shaped convection appeared at the bottom of the thermal (as shown in Fig. 8.12). The finger-like droplets made the mass and momentum exchange between the thermal and the lower water, which had a certain influence on the lateral movement of the thermal. The effect of finger-shaped convection on the lateral expansion of thermal was characterized by the lateral expansion ratio v’/ v, where v was the lateral expansion rate of the thermal in the upper layer, and v’ was the lateral expansion rate after the thermal was blocked. For moderate stratification experiments, many of droplets leaving the thermal and entering the lower water body were caused by the Rayleigh–Taylor instability. When the thermal was blocked, these denser droplets would still pass through the thermocline into the lower water body, and took away the mass and momentum of the thermal. According to Fig. 8.13, in moderate stratification experiments, the larger the droplet size, the greater the impact on the lateral expansion. However strong stratification experiments did not follow this rule. The finger-like droplets in strong stratification experiments were all produced by double-diffusion convection. The shear caused by lateral expansion would affect the formation of double-diffusion convection, and this influence was mutual. When the shear flow was strong, double-diffusion fingers were difficult to form; if the finger occurred, the loss of mass and momentum would slow down the lateral expansion of the thermal. Zhang obtained similar conclusions in his research on the evolution of the double-diffusion salt finger in a two-layer thermohaline system with laminar shear flow (Zhang et al. 2018).

8.4 Conclusions The motion of the thermals in static stratified water bodies was studied by laboratory experiments. And motions of thermals in different water temperature structures was greatly different. Lateral diffusion was limited in the process of the thermal sinking in linear stratified environment. If there had a thermocline in the water body, the thermal would stagnate in the thermocline. Due to the difference in density between the thermal and the ambient water, or the difference in temperature and mass concentration, Rayleigh–Taylor instability or double-diffusion convection might occur at the bottom of the thermal, and finger-like intrusion would appear. This finger-like intrusion will affect the lateral expansion of the thermal. Combined with dimensional analysis, the settling velocity of the thermal in stratified environment was

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Fig. 8.12 The movement of the blocked thermal with fingers. a Original experiment image. b Vertical and horizontal accumulating concentrations duration diagram Fig. 8.13 Relationship between the lateral expansion ratio v’/v and the finger size, D was the median width of finger-like drops; ◯ was the moderate stratification experiment, and Δ was the strong stratification experiment

( U =

1 2

)( B 3 N ( Z f +Z 0 )

B2 8 N 4 ( Z f +Z 0 )

uniform environment was U =

)− 15 (

+ U0 . The settling velocity of the thermal in ) 1 B2 + U0 by the same method, which was Z f +Z 0

consistent with the existing research results. Acknowledgements The study was supported by the Natural Science Foundation of Hunan Province, China (Grant No. 2021JJ30704), Changsha Municipal Natural Science Foundation (Grant No. kq2014102), the Open Research Fund of Engineering and Technical Center of Hunan Provincial Environmental Protection for River-Lake Dredging Pollution Control (Grant No. EPD202101).

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References Batchelor G, Moffatt K et al (2000) Perspectives in fluid dynamics. Cambridge University Press, Cambridge Bush JWM, Thurber BA, Blanchette F (2003) Particle clouds in homogeneous and stratified environments. J Fluid Mech 489:29–54 Chen B, Luo L, Jia LI et al (2010) Salt-fingering of pollutant vertical mixing in static thermalstratified water. J Hydrodyn 22(3):430–437 Deng Y (2003) Study on the water temperature prediction model for the huge and deep reservoir. Sichuan University PhD thesis Han X-G, Huang T-L (2010) Statistical analysis of sudden water pollution accidents. Water Resour Prot 26(1):84–86 Kabacoff R (2015) R in action: data analysis and graphics with R. Manning Publications Co., NY Lai ACH, Zhao B, Law AW-K et al (2015) A numerical and analytical study of the effect of aspect ratio on the behavior of a round thermal. Environ Fluid Mech 15(1):85–108 Landeau M, Deguen R, Olson P (2014) Experiments on the fragmentation of a buoyant liquid volume in another liquid. J Fluid Mech 749:478–518 Li CW, Ma FX (2003) Large eddy simulation of diffusion of a buoyancy source in ambient water. Appl Math Model 27(8):649–663 Scorer RS (1957) Experiments on convection of isolated masses of buoyant fluid. J Fluid Mech 2(2):583–594 Tarshish N, Jeevanjee N, Lecoanet D (2018) Buoyant motion of a turbulent thermal. J Atmos Sci 75(9):3233–3244 Xu H-X, Ren H-S (2004) The application of EXCEL and “plan to ask and solve” function in fitting curve equation. Agric Netw Inf 2:37–39 Zhang X-F, Wang L-L, Lin C et al (2018) Numerical study on tilting salt finger in a laminar shear flow. Phys Fluids 30(2):022110

Chapter 9

Water Under Pressure—A Model for Evaluating the Impact of Economic Growth on Water Resources Desislava Botseva , Nikola Tanakov , and Georgi Nikolov

Abstract Globalized economies, globalized societies, globalized challenges— human evolution goes hand in hand with the contemporary problems of current societies. Economic growth takes its elevated price, assembling the topic of sustainable development multifaceted and binding the wide variety of economic, governance, social, and environmental issues it should cover in the transition to sustainability. One of the modern challenges that await a just answer is the effective management of water resources. This management is obliged to balance water resource usage in different national and regional economies and between different economic sectors to meet both the needs of modern development and those of future generations. This approach requires all stakeholders—political actors, business, society, and science to play their fundamental roles and intensify their efforts towards a sustainable green transition of national economies. The present study carried out an independent assessment of the ability of the Bulgarian national and regional economies to walk the path to decoupling economic growth from water usage through the proposed author’s methodology. Keywords Water usage · Economic growth · Sustainability

9.1 Introductory Words Since the dawn of human history, water has been a critical factor in social, economic, cultural, agrarian (farming), regional, urban, transport, commercial, and any other form of evolutionary growth. However, its utilization for the progressive development of humanity also gives rise to responsibility for sustainable consumption, protection, and development as a resource of progress. Since ancient times, but even today, water resources have acquired various strategic meanings, ensuring human civilizational development but also the very existence of man. Although innovations are developing D. Botseva (B) · N. Tanakov · G. Nikolov University of National and World Economy, Sofia 1000, Bulgaria e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_9

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dynamically, limited resources still require societies to recognize the principles of their sustainable usage in order to be able to guarantee the future of future generations. However, not all regions face equal footing regarding their access to water resources, quality, quantity, and utilization. Of particular importance today is the need to study the geostrategic water meaning. Although it is not the specific focus of the present study, it indirectly relates to the conducted empirical research. This approach includes the functions of the water sector to provide transport and intermodal connectivity, as well as the modern expression of water as hydro-diplomacy—a framework for building regional cooperation. Hydro-diplomacy is a modern tool for implementing integrated management of water resources at the national and transboundary levels per a peace-seeking cooperation model among riparian countries. This collaborative approach to transboundary water management leads to sustainable economic benefits for all coastal states and ultimately helps to achieve Sustainable Development Goals. Sustainable development is one of the leading directions of regional policy in Europe. Intelligent systems implementation for achieving sustainability is a gaining popularity in directing development (Vasileva et al. 2022). Other modern approaches related to the need to achieve sustainability explore the heightened demand for planning and implementing hydro-innovations to increase the efficiency of the water used in production activities in the various economic sectors. Thus, for example, global corporations, in response to the growing consumer demand for sustainable products in times of global challenges such as climate change, water scarcity, and people’s health, create innovative business strategies to satisfy this need. Increasingly, they talk about the “zero footprint”, which sets new industry standards and is a priority for new corporate strategies. In this way, business dictates the new eco-paradigm, to which the regions should adhere if they have ambitions to be investment attractive. In their conceptual essence, such strategic approaches are a “win–win” scenario, but their practical implementation meets its roadblocks. In addition, individual national governments should work in line with the Sustainable Development Goals of the United Nations and the Paris Agreement on climate change. They set many ambitious targets related to carbon footprint, wastewater, and waste of resources. By 2030, the world could face a 40% water shortage if we don’t change the way water is managed. The total demand for agricultural products will grow by about 60% in 2030 to meet the growing population and higher income demand.

9.2 Research Methodology The need to decouple water from socioeconomic development is increasing. In other words, the rate of water resources used increases at a rate lower than that of the economic growth of individual national economies. To some extent, we could observe a similar trend at the global level, but it is different for all countries and all regions. Global action to decouple water from economic growth is essential to overcome the

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looming water crisis, meet global water demand, and sustain economic growth and human well-being. Problem statement: The current study research team offers an independent assessment of the decoupling degree of economic growth from water usage in Bulgaria and the Bulgarian regions. The methodology has been empirically tested in the Bulgarian economy sectors over ten years but could be applied at a supranational level. The authors of the present study consider that, although there is an active discussion on the sustainability of the water sector globally, the academic literature works implicitly on studies of the relationship between water and the economic development of individual regions. This deficit creates an increased need to properly study, plan, use, and protect water resources to achieve national and business strategic and sustainability goals. Aim of the study: For the general purpose of the present study, the author team set out to realize an independent assessment of the economic development impact on the water sector and to identify the absence or presence of an opportunity to separate this impact. Object and subject of the study: The growth and development of the Bulgarian national and regional economies is defined as the object of the present study. The subject of the study is the interdependence between economic development and the consumption of water resources. Working Hypothesis: The study’s authors will test the hypothesis that “Decoupling the impact of economic growth on the water is already happening and is to be deepened by the right targeting of policy levers and sustainability strategies.“ For empirical verification of the hypothesis, statistical data series is applied from Bulgaria’s only official source of statistical information—NSI. The study period covers the ten-year from 2010 to 2020—the last year with available empirical information on the studied indicators. Statistical information on the economic indicator GDP is applied for the same time period. Data are collected, empirically tested, and aggregated at the national and regional economic levels. An important limitation of the study here is that there is some divergence between “planning regions” —NUTS 2 and water regions in Bulgaria. Therefore, to overcome this limitation, the study was conducted at the NUTS 2 level, regardless of which water regions the examined territories fall into. The collected water information quantitatively covers the water cycle’s individual parts (water abstraction, usage, wastewater). The final results for water usage are obtained by calculations from actual data from observations and by applying balance methods, structures, and calculations. An important limitation of the study is that the accuracy of water data is primarily determined by how respondents record water amounts. According to the study’s authors, the creation of strategic documents at the regional and national level for the sustainable usage of water resources and, in parallel, their expenditure for socio-economic development should rest on similar scientifically based methodological approaches. The UN, the EU, and the national economies have recognized the issue of reasonable water usage as a priority in their

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conceptual approaches. It is time for science and practice (including political will and business) to occupy their fundamental positions in practical application.

9.3 A Few Words About European Water Urbanization and growing domestic and industrial needs, improper operation and maintenance of sewage systems, pollution, and water usage, even in sectors with available alternative solutions, combined with the effects of climate change, generate severe pressure on the Old Continent water reserves. This pressure is both on their quantity as well as their quality. According to recent studies, nearly 80% of the freshwater used for drinking, industrial and agricultural needs in the EU is provided by rivers and groundwater. Therefore, these sources are becoming the most vulnerable to threats from overexploitation, pollution, and climate change (EEA 2018a, b). • Over 40% of the total water in Europe is used in agriculture. In the spring months, when additional irrigation of cultivated land is needed, this percentage reaches 60. The decrease in precipitation due to climate change is increasing this rate, especially in the more drought-affected areas of southern Europe; • 28% of the annual water consumption in the Old Continent goes to energy production; • 18% is the consumption of mines and industrial production; • Only 12% goes to drinking needs. Observing the Old Continent, we might get the impression that freshwater resources were abundant. However, this statement is not universal. Water availability for socio-economic activities is unevenly distributed, leading to disparities in water stress in different seasons, sectors of the economy, and regions. The European Environment Agency, in a technical report from 2018, warned that the increased demand for water in recent decades has led to a reduction of renewable water sources per capita by 24% across Europe. At the end of 2020, water abstraction in the European Union has decreased by 21% compared to the level of 1990 due to the requirements adopted by Brussels and at the national level. These data, although they seem encouraging, are parallel to a number of circumstances. Hot periods and those without precipitation and snow are constantly increasing, which increases water consumption. The regions of Southern Europe, including Bulgaria, are the most affected. One of the reasons is the lower amount of precipitation on an annual basis. In addition, dynamic urbanization growth impacts the growth of water use, a problem concentrated in densely populated areas.

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9.4 Water Sector Relationship with the Economic Development of Bulgarian Regions According to World Resources Institute data for 2020, a significant part of our country’s territory is under extreme water stress. It reaches indicators of 80% risk of issues with the freshwater provision in Western and Southern Bulgaria, including Sofia, Plovdiv, and Stara Zagora regions, and part of the Rhodopes. Those territories have high levels of water stress and an index of over 40%. Most of Central and Eastern Bulgaria are at low risk, below 10%. Therefore, on average, Bulgaria is placed 54th regarding water stress with an overall average risk. Nevertheless, as areas with extreme levels of water stress are the most densely populated, the issue of taking urgent measures remains urgent (KEVR 2018). The Bulgarian economys and its region’s sustainable development needs to recognize decoupling as a top priority in its strategic approaches. At its core, “decoupling” refers to the ability of an economy to grow without increasing pressure on the environment. In scientific literature and strategic documents, terms such as “green economy” and “green growth” are synonyms for this process. By its nature, the decoupling of resources from economic development occurs when economic growth exceeds the resource usage rate. Therefore, the economic productivity of resources increases, as does the efficiency of production processes. This approach to sustainability is essential when a resource is scarce, and its unwise use threatens to deplete it. Resource consumption threatens both social and economic progress, as well as the future development of future generations. In the Bulgarian reality, decoupling water usage from economic growth is particularly important in areas where water resources are under pressure, and there is a risk of depletion. We can talk about effective separation when the impact on the environment decreases. In the Bulgarian reality, our national economy faces many challenges for which it should find sustainable solutions. One of the essential directions is to succeed in meeting the constantly changing requirements for regional competitiveness. On the one hand, the new reality we live in, brought about by the post-Covid-19 crisis, military conflicts, the subsequent energy crisis, and economic inflation, requires a timely response to mitigate the negative impacts. On the other hand, the everincreasing criteria (ISO 14001) and requirements for compliance with the strategic goals of international corporations, which are an excellent opportunity to attract investments, make the task of the Bulgarian regions particularly difficult. At the same time, transforming the Bulgarian regional economies into investment-attractive is crucial for mitigating the negative consequences caused by cataclysms generated at the national and global levels.

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9.5 Empirical Testing of the Working Hypothesis All economic sectors use water, albeit in different ways and different volumes. Access to sufficient fresh water is critical to many economic sectors and communities that depend on these economic activities. In the current study, the author’s team will test how the amount of water used to produce a unit of GDP has changed over ten years from 2010 to 2020. In this way, we can verify the possibility of decoupling the impact of economic growth on water resources. Table 9.1: Bulgaria’s Gross domestic product shows the GDP indicator’s values at the national level for the studied period. The data are borrowed from NSI, 2010–2020 (Fig. 9.1). As can be seen from the presented data for the ten years, the GDP of the Bulgarian national economy realized continuous growth, albeit at variable rates over the years. Table 9.2 shows the water consumption values for the same period. It is important to note that the indicated water consumption values are measured by economic sectors, in general, for the country and all its regions (Fig. 9.2). As evident from the provided data, water consumption decreased over the ten-year study period, despite a consistent growth in GDP across sectors. It is noteworthy that there are some fluctuations in the decline; nevertheless, the overall trend indicates a decoupling of economic growth from water consumption. The ratio of water usage to GDP in the Bulgarian economy sectors is illustrated in the following figure (Fig. 9.3). Table 9.1 Gross domestic product of Bulgaria Country total 2010

2011

2012

2013

2014

2015

2016

2017

2018

2019

2020

GDP/million e 38,399 41,602 42,383 42,175 43,154 45,949 48,918 52,688 56,392 61,742 61,822

Fig. 9.1 Gross domestic product of Bulgaria

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Fig. 9.2 Water used by economic activities

Fig. 9.3 Ratio of water usage to GDP Table 9.2 Total amount of water used Total amount of water used 2010 (Ml

2011

2012

2013

2014

2015

2016

2017

2018

2019

2020

4559

4477

4506

4736

4721

4732

4647

4579

4310

m3 /year)

4821

5178

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Fig. 9.4 Decoupling achieved

While water usage decreases or remains relatively constant, the GDP realizes constant growth over the years. E.g., for the year 2010, 0.125 ml m3 is needed to produce a unit of GDP compared to 0.069 ml m3 needed to produce a unit of GDP in 2020. For the entire studied period, the reduction in economic growth’s impact on water resource usage is presented in Fig. 9.4 which expresses the achieved decoupling of water resource usage from economic growth. The generated statistics make it possible to trace the regional disparities according to the methodology used and thus to trace whether the pace of Decoupling is uniform in the studied territory. For this report, in Fig. 9.5 we will present only the output data of the empirical tests performed. From the graph presented, we can conclude that all Bulgarian NUTS 2 regions manage to significantly reduce the amount of water used to produce a unit of GDP, but there are significant regional disparities. Part of the reasons for these differences depends on the typical regional profile and the developed regional intelligent specialization of the respective territories. Others can be attributed to the degree of innovation involved in using water for economic activities. Nevertheless, in Bulgaria and the Bulgarian regions, there is a sustainable foundation for continuing and deepening the Decoupling impact. It is necessary to continue government and business efforts in this direction so that the Bulgarian economy can guarantee its green transition and sustainability.

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Fig. 9.5 Decoupling achieved per NUTS 2

9.6 Conclusion To adequately address the challenge of reducing water use to sustainable levels and achieving decoupling, it is necessary to understand what drives water demand and use development. To adequately address the challenge of reducing water usage to sustainable levels and achieving decoupling, it is necessary to understand what drives water demand. The main reasons behind the overexploitation and pollution of waters are the result of human activities and economic sectors. This includes agriculture, industry, energy, and general needs. All of them are driven by economic development and growth. Government policies, including food and energy security policies, as well as other factors such as consumption patterns and globalization of trade, also contribute to changes in water use (UN-Water 2015). In addition to all this are the challenges generated by the current picture of climate change. This, in turn, will increase the demand for water to service economic activities, including agricultural ones. Another reason that generates an increase in the global demand for water consists of dynamic urbanization. Rising incomes and living standards, in turn, lead to a sharp increase in the amount of water used, which is only sometimes sustainable. Population growth is another factor that affects water demand. Changing consumption patterns, building larger homes, and using more motor vehicles, appliances, and energy-intensive devices, involves increased water consumption for production and use (UNEP 2015). It is expected that the demand for water will increase significantly

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in the coming decades, and the forecasts are not at all optimistic. Water consumption is expected to increase in all production sectors, with the vast amounts consumed by agriculture and energy further exacerbating this problem. Practices such as efficient irrigation techniques can dramatically reduce water demand, especially in rural areas. Many of the pressures affecting water sustainability occur at local and national levels and are influenced by rules and processes established at these levels. However, the rules and processes governing the global economy—capital investment, trade, financial markets, and international and development aid—increasingly influence local and national economies, which in turn dictate local water demand and sustainability (Dimitrov et al. 2022). The appropriate combination of these mechanisms with dynamically generated innovations, adequate water use planning for economic activities, legislative and regulatory changes, and creating national and regional water-use strategies are part of the mechanisms for achieving sustainability to guarantee the future. However, this is not enough to harness the future challenges that humanity must face in sustainability. It is necessary for all stakeholders: public authority, private sector, society, and academia to work collaboratively to find the right solutions to future challenges. Acknowledgements The paper is part of a research project titled HID HI-26/2023/B, “Regional aspects in the formation of the modern demographic picture—development of the population of Bulgaria (2030) scenario,” financed by the University of National and World Economy via the program for Scientific and research activities.

References Dimitrov D, Velikova E, Bogomilova E (2022) Policy of the Republic of Bulgaria in the field of natural and environmental disasters. In: Jeon HY (ed) Sustainable development of water and environment. Environmental Science and Engineering. Springer, Cham. https://doi.org/10.1007/ 978-3-031-07500-1_25 EEA, Use of freshwater resources (2018a) Homepage, https://www.eea.europa.eu/data-and-maps/ indicators/use-of-freshwater-resources-2/assessment-3/. Last Accessed 39 Mar 2023 EEA, Water use in Europe—Quantity and quality face big challenges (2018b) Homepage https:// www.eea.europa.eu/signals/signals-2018b-content-list/articles/water-use-in-europe-2014. Last Accessed 29 Mar 2023 KEVR, Sravnitelen Analiz na ViK Sektora v Republika Bulgaria za 2018. https://www.dker.bg/upl oads/documents/vik/sravnitelen-analiz-vik-2018.pdf. Last Accessed 39 Mar 2023 National Statistical Institute Homepage. https://www.nsi.bg/. Last Accessed 39 Mar 2023 UNEP (2015) Options for decoupling economic growth from water use and water pollution. Report of the International Resource Panel Working Group on Sustainable Water Management UN-Water (2015) The United Nations World Water Development Report 2015: water for a sustainable World. Paris, UNESCO

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Vasileva E, Lyubomirova V, Tsolov G (2022) Sustainable cities via smart development strategies: Bulgarian case. In: Jeon HY (eds) Sustainable development of water and environment. Environmental Science and Engineering. Springer, Cham. https://doi.org/10.1007/978-3-031-07500-1_ 24 World Resources Institute, AQUEDUCT, Water Risk Atlas (2020) Homepage. https://www.wri. org/. Last Accessed 29 Mar 2023

Chapter 10

Mineral Water Resources Management in the Bulgarian Regions Veselina Lyubomirova , Elka Vasileva , and Georgi Tsolov

Abstract The territory of Bulgaria is one of Europe’s oldest and richest geothermal spring regions. In the country are currently known hundreds of mineral water deposit fields. State regulations and municipal strategies for exploitation and new investments in mineral water resorts categorized with national significance are analyzed. Based on state legal and local strategic frameworks, opportunities for better planning and development of the mineral water fields and facilities are outlined. The goal is to outline a systematic picture of the local authoritie’s engagement with the mineral water resources. However, the paper is based on a national case study; the maintenance and impact of the mineral waters with their health support qualities are important regionally for European citizens. Research on the Bulgarian case study in this area has been almost missing in the last decade, and a case study can contribute to further European comparative research. Nationally is the first comparative analysis on that topic. Keywords Mineral water springs · Balneo tourism · Geothermal energy · Bulgaria

10.1 Introduction The topic is related to the worldwide increased attention on the efficient use of water resources but regulated by local and national policies. In this regard, mineral water is one of the most significant natural resources in Bulgarian municipalities but is almost missing in scholarly publications, even on a national level.

V. Lyubomirova (B) · E. Vasileva · G. Tsolov University of National and World Economy, Sofia 1000, Bulgaria e-mail: [email protected] E. Vasileva e-mail: [email protected] G. Tsolov e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_10

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The Bulgarian mineral water resources are national but also regional and a European capital with health treatment characteristics and the capacity to improve regional tourism development. However, due to the fragmented and not scientifically analyzed information about the conducted local policies and measures for effective management of mineral water springs use, the author’s interest is focused on investigating the local governance efforts in this sector. Over 550 deposits with 1600 mineral springs are being explored in the country, with a total flow between 3000 and 4900 l/sec (Water Act [of Bulgaria] 2022). Mineral water resources are used for water supply (where no other source is usable), bottling potable water but primarily—for rehabilitation in medical facilities, and combined applications, including balneology and heating. Almost all of them are thermal, as the temperature varies in a wide range from 20 to 100 °C (Bojadgieva et al. 2002). So far, most analyses of Bulgarian mineral water resources are from national scholars in the geological (Hristov et al. 2019) and medical fields of study (Vassileva 1996). Just recently were published several economic studies about mineral water resources in Bulgaria. Some are focused on SPA facilities and resorts and the efficient and profitable water resource use for private hotel owners (Velikova and Anev 2019) or the health and tourism impact of balneo resorts (Stankova and Kirilov 2017). Others are focused on potable bottling capacity and the potential for better national profit from this sector (Tuntova 2020). Rara are also the comparative studies. Such recent papers compare Bulgaria and Serbia (Staneva and Vachkova 2018), and others discuss the possible transfer of good practices in geothermal heating from Austria to Bulgaria (Trayanova et al. 2020). The paper’s results constructed a systematic picture of the public management plans and efforts regarding the significant resource as the mineral waters are.

10.2 Research Approach The research approach is based on systematically observing a case study based on Bulgarian mineral water-related policies. The analysis is constructed in three parts: relevant theoretical and new evidence-based research on the case; research on the significant insights from the national legal and strategic framework; analysis on subcases from Bulgaria—all 19 balneo resorts categorized with state significance for the tourism and more for the recreational and health sector (Council of Ministries 2012). On national level is analyzed the existing legislation and strategic framework for exploitation of mineral water springs and balneo resorts. The first analytical line in this section is from the Ministry of Environment and Water with their Water strategy until 2030 with an appendix about mineral waters. The legislation part used the Water Act. According to the balneo resort content, our focus is on the Ministry of Tourism’s newest policy in the area—the announced new balneo tourism destinations and the Strategy for sustainable tourism development until 2030. Additionally

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are analyzed three other laws—The Health Act, Concession Act, and Energy efficiency act. With this cross-ministry information is constructing the cross-sectoral engagement of municipalities regarding the mineral water management on their territory. On the local level are analyzed sub case studies—the 19 balneo resorts with the status of national significance achieved mainly based on the number of mineral water springs on their territory and the quality of the mineral water for health purposes (Balneo and SPA destinations (in Bulgaria) [in Bulgarian] 2023). The resorts have the national recognition status since the 50s, 60s and 70s of the XX century, achieved also based on these days planning policy for their development. Currently, they still have such status with significant legislation and strategic planned engagement, but all related national and local policies are fragmented. For the paper are followed several municipal sources so to be analyzed the existing local authority policy for mineral water resources management. Included in the data are the midterm strategic development plans 2021–2027, local strategies for sustainable tourism development until 2030, energy efficiency strategies until 2028, municipal webpages, and additional information in other local documents with thematic relevance. The researched hypothesis was that the mineral waters are outside the municipal policy focus as a resource outside the tourism sector. Based on that preliminary understating and the missing systematized data on the national level, our task was to analyze the national policy framework, the local policy framework, and the current stage of the mineral water sector management in the different regions. Constructed are two indicators groups for the sub-case studies. The first is evidence of mineral water public infrastructure, and the second is evidence of management plans, projects, and measures regarding mineral water resources. The analysis follows the presumption that municipal authorities recognize their territory’s mineral water leverage but still need to implement it as a leading resource for their investment and development policies.

10.3 Bulgarian Mineral Water Landscape Currently, after different legislation changes, municipalities receive mineral water springs from the state for 25 years for free use. This is an ongoing process of state property letting and made the question of these resource management from growing significance. However, local authorities were firstly interested but so far raising awareness about their difficulties in funding and managing the efficient exploitation of the springs (National Association of the Municipalities in the Republic of Bulgaria 2022). The first problem is that Bulgarian municipalities have poor financial decentralization, especially the smaller ones (Pavlova-Banova and Aleksandrova 2021). Exactly small municipalities have balneo resorts on their territory. According to our observation, the second problem is the existing deficit of professionals for management and policy development regarding this specific resource. One of the

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main reasons is that the mineral water resources have been under proper national and local public management for decades (see Table 10.1). Table 10.1 shows that public management engagement has been neglected for years, and this gives us the motive to investigate the fragmented existing policies and measures. In the last 33 years, most municipal efforts were related to attracting private investors for high-star hotels with mineral water concessions and to up-given public facilities for balneo services. Concession contracts for potable water bottling were the other main municipal and state interests. Public infrastructure and a more systematic approach to the mineral water resource were not on focus. Nowadays, management responsibility in the area recruits attention in three directions: balneo resort’s resilient development, geothermal energy sustainable use, water bottling, or/and water supply. European significance of the topic Bulgaria is among European Union’s leading SPA and health tourism destinations (Papadopoulou 2020). “European Union citizens can use the balneo centers in Bulgaria for preventive care and rehabilitation, as their national health insurers cover up to 90% of the cost of procedures and treatments and significantly under EU average accommodation prices (Staneva and Vachkova 2018; Concession act [of Bulgaria] 2023). Of the international balneo tourists, 38% are from the Balkans, 23% from West Europe, and 22% from East Europe. Most of the international tourists are from Russia (21,6%), Greece (20,4%), Germany (13,1%), Great Britain (9,1%), North Macedonia (6,9%), Romania (5,4%), Turkey (3,0%) ([Bulgarian] 2030). Balneo resorts: The resorts are often municipal centers but sometimes are towns or villages in some municipal territory. As a resort, they do not have specific management administrations. Instead, their management is an engagement of the local authorities as part of the general municipal development plans and policies. However, the mayor and Table 10.1 Development of mineral water resort in Bulgaria due years Years between 1950 and 2000)

The exploitation of mineral water resources in Bulgaria

50 s–60 s—70’s

Extensive hydrogeological exploration; Building of dozens of balneo sanatoriums centers (nearly 40); Developing the network of balneo resorts with national significance

After the’80 s

Constructing of geothermal heating installations locally for balneo facilities

After the ‘90 s

Decrease of governmental support for balneo infrastructure

After 2000

Legislative reform for national, regional, and local management of the water sector, incl. mineral waters. The reform is ongoing, and even planned to end in 2006 (Tuntova, 2020)

Source The authors, based on (Bojadgieva et al. 2002; Vassileva 1996; Tuntova 2020)

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municipal council are responsible for the public mineral water facilities, the infrastructure, and transport connections to other mineral water spots in the resort. Resort management includes public mineral water pools and facilities such as public baths and mineral water fountains for drinkable water. From research significance of this paper is the public infrastructure related to balneo resorts: working public pools, potable fountains, public baths, state-owned balneo centers, and hotels. Geothermal energy: Together with balneo tourism, in the last years, the role of renewable energy sources has also been increasing in Bulgaria (Hristov et al. 2019). EU and national finds support projects for public buildings heating. This option depends on the original water temperature and other geological factors. Even though only some resorts and municipalities are in this capacity, the general scientific conclusion is that most can implement the water heating infrastructure. So far, municipalities have to analyze their resources in this regard. Some may have the capacity for geothermal heating centers to power more buildings. Others can equip with such installations several buildings but one by one with single installations. Important for us is to search how many municipalities have such plans and projects. Water bottling or/and water supply: Bottling potable mineral water has been one of the very fast-developing businesses in the last 30 years. At this time, the number of bottling factories increased from 3 to more than 40 (Trayanova et al. 2020). Tourists and locals use the water for drinking, self-booting, and stocking up for longer periods. In most resorts, mineral water drinking is part of some rehabilitation treatments for different health conditions.

10.4 Results and Discussion The national legislation requests that local authorities of the municipality with a nationally recognized resort on its territory are obliged to plan expenses for improvement, development, and facilitation of tourism infrastructure, public tourism products and services, etc. The tourism infrastructure includes a general city and resort infrastructure (Tourism act [of Bulgaria] 2022). However, more importantly, they are responsible for public mineral water baths, fountains with drinking water, and public swimming pools with mineral water. These specific responsibilities are not one by one included in the Tourism Act but are functionally part of the status of a resort with national significance. Results from the investigation of the national policy framework regarding mineral water management: In the last two decades, the legislation in Bulgaria has opened different opportunities for the exploration, use, and preservation of mineral water resources. As a

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result, several laws form the normative framework for mineral springs management (Table 10.2). Table 10.2 illustrates that municipalities can have management responsibility for the mineral water resources on their territory for two decades and a half. This option is given for mineral water springs needing further construction and exploitation development. So far, the normative framework allows more economically relevant use of still poorly exploited mineral water springs. The legislation provides municipalities with the opportunity for efficient management of mineral water resources. They can plan investments for exploitation, including public–private partnerships related to SPA, sport, balneology, heating of public buildings with geothermal water, and even rehabilitation with thermal water in municipal hospitals. However, the efficient use of mineral water springs depends on the local authorities initiative to include them in the strategic development plans as a resource, not just a natural characteristic of their territory. Local-level good governance and administrative management are leading preconditions for investment climate improvement in the mineral water sector. The national mineral water recourse management policy places municipalities as the primary users and managers of the mineral waters (Ministry of Environment and Water: Strategy for Mineral Water Management and Measures 2023). This role is even more challenging when “health tourism is not a national priority (undeveloped national health tourism strategy)” according to the National strategy for sustainable tourism until 2030 ([Bulgarian] 2030. Results about the municipal current stage of mineral water infrastructure policy development management:

Table 10.2 Normative framework regarding mineral water management Normative document

Essence

Water Act (from 2001) (2022)

After 2011 the law stipulates decentralization options for exclusive state-owned mineral water springs; The regulation gives a right of local authorities the free use of mineral water springs for 25 years. They have an obligation to manage the springs as public municipal property, including exploitation, preservation, etc. This is an option, not an obligation. Municipalities can apply for state-owned mineral water springs when such are not under concession or in use by medical facilities, SPAs, etc

Concession Act (from 2018) (2023)

Concession contracts can be with the state or the municipality, depending on the responsible authority for the concrete spring

Energy efficiency act (from 2008) (2023)

Regulates the conditions for geothermal energy use and management

Health Act (from 2008) Define and control the mineral water springs (2023) Define the requirements for mineral water bottling Decrees priority use of mineral water for the specialized work of health facilities, including when these thermal resources are under concession regulations Source The authors, based on the national legislation

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Table 10.3 are presented the results from or subcases analysis based on a mix of local strategic programs and plans and other public information about municipalities with resorts of national significance on their territory. In section A are systematized all public infrastructure components for the specific balneo tourism needs. In section B are systematized possible directions of mineral water management and their current state of development. This quantitative data was not outlined and compared before. Mineral water maintenance and management is a territorial responsibility, which means primarily municipal engagement in development, public infrastructure, and attracting private investors for public–private partnerships. Public infrastructure specialized for balneo tourism needs and according to the traditions in Bulgaria are resorted to public mineral water pools and baths, working balneo centers and hotels but also measures, plans, and projects for future development. The expected projects which we have searched for are as follows: strategies or measures in other documents for the development of the mineral water resources maintenance and management; plan and projects for mineral water supply for other resort territories, for example, for new hotels or bottling concession where the water is potable; geothermal projects for public buildings or hotels heating; and last but not least—strategies for mineral water tourism marketing. The monitoring in section A shows that almost all resorts have the infrastructure for balneo services, and on that bases—the potential for high exploitation and impact from mineral water resources. Section B shows that nine from 10 municipalities with resorts do almost not mention mineral waters as a resource in their strategic development documents. In the other ten municipalities, mineral waters are included in different strategic documents but are still not a leading priority. This is disturbing because neither municipality from the table is a big city or sufficiently industrialized. These are small cities and towns, mainly in the mountains or less developed territories, suffering from population decrease, often with difficulties in finding investors, sustainable workplaces for the local citizens, etc. In this regard, mineral waters are expected to be considered a valuable resource in all possible strategic directions. Exception from this tendency is municipal plans for water concessions or water supply to areas with investor’s interest. Less than half of the municipalities have plans to use geothermal energy for heating, even when national and EU funding is available for such projects. All municipalities neglect their role in tourism marketing. The health support impact of their resorts does not exist not existing in either of the local documents as a possible additional resource to the represented place.

10.5 Conclusion The results from the in-depth municipal monitoring confirm that for the local authorities, mineral water springs are more of a natural characteristic than a significant and unique resource. In most tourism strategies, on focus are planned measures for all possible forms of tourism but not for balneo tourism. Other exploitation possibilities

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Table 10.3 Comparative picture of the national mineral water /balneo/ resorts in Bulgaria Baleoresorts

A/ Mineral water infrastructure (public mineral water pools; public mineral water baths; state and union-owned balneo centers; privately owned balneo hotels:

B/ Management plans/projects for balneo tourism development; bottling or spa facilities water supply; geothermal heating of public buildings and hotels; thermal towns marketing initiatives:

Public Public Balneo Balneo Balneo Water Geothermal Thermal pools baths centers hotels tourism supply/ projects towns development bottling marketing Kyustendil

✓

✓

✓

✓

✓

✓

✓

✕

Velingrad

✓

✓

✓

✓

✕

✓

✓

✕

Sandanski

✓

✓

✓

✓

✕

✓

✓

✕

Pavel banya

✓

✓

✓

✓

✕

✓

✓

✕

Hisarya

✓

✓

✓

✓

✓

✓

✕

–

Burgas mineral ✓ baths

✓

✓

✓

✕

–

Stara Zagora mieral baths

✓

✓

✓

✓

✓

✓

✓

✕

Sliven mineral baths

✓

✓

✓

✓

✓

–

–

✕

Haskovo mineral baths

✓

✓

✓

✓

✓

–

–

✕

Strelcha

✓

✓

✓

✓

✓

–

✓

✕

Narechen mineral baths (Asenobgrad)

✕

✕

✓

✓

✕

–

✕

✕

Momin prohod ✕ town (Kostenets)

✓

✓

✓

✕

–

✕

✕

Vili Kostents (Kostents)

–

–

✓

✓

✕

–

–

✕

Merichleri ✓ town (Dimitrovgrad)

✕

✕

✓

✓

✓

✕

✕

Varshetz town

✓

✓

✓

✓

✓

✕

✕

✕

Bankya town (Sofia)

✓

✓

✓

✓

✓

✕

✕

Banya village (Panagyuriste)

✓

✓

✓

✓

–

✕

✕

✕

✕

(continued)

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Table 10.3 (continued) Baleoresorts

A/ Mineral water infrastructure (public mineral water pools; public mineral water baths; state and union-owned balneo centers; privately owned balneo hotels:

B/ Management plans/projects for balneo tourism development; bottling or spa facilities water supply; geothermal heating of public buildings and hotels; thermal towns marketing initiatives:

Public Public Balneo Balneo Balneo Water Geothermal Thermal pools baths centers hotels tourism supply/ projects towns development bottling marketing Banya town (Karlovo)

✓

✓

✓

✓

✓

✕

✕

✕

Berkovitsa

✓

✕

✕

✕

–

✓

✕

✕

Source Author’s systematization based on content analysis of existing municipal documents and public information Legend: ✓ Planned and existing measures and projects; ✕ Missing measures and projects; – Not applicable

of the mineral water resources are also not on focus in the examined local strategic documents. So far, we have achieved a general picture of the ongoing mineral water management responsibilities on a local level. We do not have a column about new investments in exploring water springs because such does not exist. Most of the municipalities do not plan to start such projects because of the expected costs and, so far, no existing external (state or EU) funding for such initiatives. Bulgaria is a country of mineral waters with more than 600 mineral water deposits, 19 (examined here balneo resorts with national significance) and another 35 balneo resorts with regional significance. The papers show that even the resort with the official national significance status is not a priority for the local authorities. Moreover, 7 of the examined resorts are also central municipal towns. In a time of intensive debates in Europe and worldwide for water-efficient and intelligent use (Botseva et al. 2022), and when the world overcomes health crises, the responsible local authorities neglect the complex potential of mineral water resources. We hypothesized that only the balneo impact is on focus, not the geothermal and water provision. The results show that even tourism development based on the health tourism concept is outside the municipal and resort management’s current priorities even when they are responsible by law for developing the resorts as such with national significance. Although the EU and European citizens are potential users of balneo resorts, responsible municipalities do not have developed marketing strategies to attract them. These results can be used in comparative research among other European countries rich in mineral waters. For Bulgaria is a base for policy recommendation and discussion with stakeholders related to the topic but also a first step in the research of the next level mineral water resorts—these 35 of them with intraregional significance according to the state classification. Finally, this classification was formally updated in 2012However, the results reveal that from the first announcement of the statute, “balneo resort with national significance” in the middle and second half of the XX

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century,” the policy framework for such development and management is underdeveloped and abandoned despite some current law obligation of local authorities for maintaining and building of tourism infrastructure. Acknowledgements The paper is part of the project HID HI-27/2023 Regional Opportunities spatial analysis on the territory of Bulgaria for strategic localization of industrial zones, financed by the University of National and World Economy.

References [Bulgarian] Strategy for sustainable tourism development in Bulgaria until 2030, Ministry of Tourism. https://www.tourism.government.bg/sites/tourism.government.bg/files/uploads/str ategy-policy/strategy_2014-2030_13_05_2014-sled_ms_26_05_2014.pdf Balneo and SPA destinations (in Bulgaria) [in Bulgarian], Ministry of Tourism (2023). https://www. tourism.government.bg/spa-destinations/6458. Last Accessed 27 Mar 2023 Bojadgieva K, Dipchikova S, Benderev A, Koseva J (2002) Thermal waters and balneology in Bulgaria. In: Balneology in Bulgaria, ch. 1.3 Botseva D, Tanakov N, Nikolov G (2022) Intelligent water resources management. In: Jeon H-J (ed) Sustainable development of water and environment, Springer, pp 263–273 Concession act [of Bulgaria], last changed 23 January (2023) available at: https://lex.bg/bg/laws/ ldoc/2137178490 Council of Ministries: List of resorts in Bulgaria and definition of their borders (2012) In State newspaper, Act 153 from 24 February 2012 br. 18 [in Bulgarian] Energy efficiency act [of Bulgaria], official from 12 March (2023). available at: https://www.seea. government.bg/documents/ZEE_12.03.2021.pdf Health Act, [of Bulgaria] (2023) last changed 25 January 2023, available at: https://lex.bg/laws/ ldoc/2135489147 Hristov V, Deneva B, Valchev S, Benderev A (2019) Geothermal energy use, country update for Bulgaria (2014–2018).In: European geothermal congress 2019, The Netherlands: Den Haag, pp 1–6 Ministry of Environment and Water: Strategy for Mineral Water Management and Measures (2023) In: National strategy for management and development of water sector in Bulgaria, available at: https://www.moew.government.bg/bg/vodi/strategicheski-dokumenti/nacionalna-strategiyaza-upravlenie-i-razvitie-na-vodniya-sektor-v-republika-bulgariya/. Last Accessed 24 Mar 2023 National Association of the Municipalities in the Republic of Bulgaria, Discussion about the opportunities for efficient use of mineral water springs in Bulgaria [in Bulgarian] (2022). available at: https://www.namrb.org/en/topical-information/obsazhdane-na-azmozhnostite-za-ratsio nalno-izpolzvane-na-mineralnite-izvori-balgariya. Last Accessed 13 Mar 2023 Papadopoulou G (2020) SPA tourism in Europe: an economic approach. Athens J Tourism 7(3):133– 144 Pavlova-Banova M, Aleksandrova A (2021) Financial resources of municipalities in Bulgaria and European Union Countries. In: Collection of papers from international scientific conference “Globalism, regionalism, security”, UNWE, Publishing Complex, So-fia, pp 65–75 Staneva K, Vachkova E (2018) Evaluation of the potential of the cross-border region Bulgaria-Serbia for the development of wellness, medical SPA, and SPAtourism—possibilities and perspectives. CroDiM 1(1):1–10 Tourism act [of Bulgaria], last changed 23 December (2022) available at: https://lex.bg/laws/ldoc/ 2135845281. Accessed 20 Mar 2023

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Trayanova M, Haslinger E, Wyhlidal S, Kinner P, Atanassova R, Benderev A (2020) Possibilities for the utilization of highly mineralized water in Central Bulgaria as a source of thermal energy, based on Austria’s experience, 72–78. Bulgarian Chem Commun 52:Special Issue C. https:// doi.org/10.34049/bcc.52.C.0031 Tuntova A (2020) Status and trends in the use of mineral water in the food industry, dissertation, [in Bulgarian], VUSI, Plovdiv, Bulgaria Vassileva S (1996) Mineral waters and SPAs in Bulgaria. Clinic and Dermatol 14:601–605 Velikova E, Anev I (2019) Value assessment of natural mineral springs water used in SPA facilities. J Econ Stud Bulgarian Acad Sci Bulgaria: Sofia 4:158–187 Water Act [of Bulgaria], last changed 11 March (2022). available at: https://www.moew.government. bg/static/media/ups/tiny/Vodi/zakonodatelstvo/ZAKON_za_vodite-2022.pdf [in Bulgarian] Stankova ZlM, Kirilov St (2017) Improving the quality of Life through Balneotourism practices: the Bulgarian experience. Ekonomia—Wroclaw Econ Rev 23/1:73–81

Chapter 11

Improving the Quality of Public Transport to Achieve Environmental Sustainability in the City of Sofia, Bulgaria Elenita Velikova

and Iliya Gatovski

Abstract Improving the quality of service in public urban transport is an important prerequisite for ensuring environmental sustainability in cities. Quality is part of the social efficiency needed to achieve sustainability in urban development, and increasing the use of public transport instead of private vehicles is fundamental to reducing the harmful impact of transport and achieving the environmental component of sustainability. development. The crises of the last three years have created a number of restrictions on the transportation of passengers, and transport operators from the field of public transport had to find new approaches to solving tasks related to its normal functioning. The most important issue facing them is to restore the confidence of passengers by providing safe and quality services. In this manuscript, based on the analysis of the state of public transport in the city of Sofia, Bulgaria for the period 2019–2022, guidelines are proposed for increasing the quality of the services offered. Improving quality, in turn, will contribute to the preference and use of public transport to a greater extent. Recommendations and measures for the future development and state of public transport in the city of Sofia, its modernization and sustainable development are presented. Keywords Public transport · Environmental sustainability · Quality · Sofia · Bulgaria

E. Velikova (B) · I. Gatovski University of National and World Economy, Sofia 1000, Bulgaria e-mail: [email protected] I. Gatovski e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_11

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11.1 Introduction Environmental pollution is one of the biggest problems of our time. It mainly affects the climate by changing it and thus endangering the lives of people all over the world. Transport is one of the sectors that contribute the most to ecological imbalance. One of the ways to contribute to nature conservation and climate change is to use more public transport services in cities, in resorts and to overcome inter-city distances. Increasing the use of public transport services over private vehicles is among the best ways to reduce harmful emissions and help protect the environment. And the possibilities to achieve this is through the improvement of the quality of the urban public transport service. Many cities have successfully managed to reduce CO2 emissions by up to 50% by reducing or limiting the flow of private cars (Ridango 2023). Transport plays a vital role for the economy and society of Bulgaria as a member state of the European Union. People’s quality of life depends to a very large extent on the availability of an accessible and efficient system of transport that meets their modern needs. At the same time, transport is a major source of pressure on the environment in the European Union (EU) and has an impact on climate change, air pollution and noise. It also requires a lot of space and leads to the growth of cities, the fragmentation of habitats and the sealing of surface soils. EU policy sets targets for an ever greater reduction in the harmful impact of transport. Some main directions in which this policy should be implemented are laid down. A significant place among them is the transition to the use of less polluting and efficient modes of transport, i.e. to changing the transport fleet, especially that used for passenger transfers. Technology, in turn, will enable greater sustainability of transport, the creation and use of new types of fuels and the improvement of infrastructure. The EU also requires an increase in the prices of transport services, which do not reflect the principles of sustainable development and have an adverse impact on people’s health and the environment.

11.2 State of the Problem One third of the final energy in the EU is used by the transport sector. To produce it, mostly oil is needed. In this way, however, greenhouse gas emissions increase, which are constantly increasing in volume. This, in turn, leads to climate change. Today, they account for over a quarter of total EU greenhouse gas emissions. There is currently no reversal of this trend (Velikova 2021). This makes the transport sector a major obstacle to the realization of the EU’s climate protection goals. More than 70% of total greenhouse gas emissions from transport are generated by trucks, buses, vans and cars,. The rest come mainly from the maritime transport and aviation sectors. In cities, the main air pollutant is transport, and more specifically the use of private cars to cover distances. They generate dust particles and nitrogen dioxide (NO2) in the air, which damage the environment and human health. Over the past decade, the

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EU has introduced significant fuel quality standards to reduce vehicle emissions and use cleaner technologies. However, this still does not produce the desired results. In addition, transport infrastructure has a serious impact on the landscape, as it divides natural areas into small areas, which has serious consequences for animals and plants. In addition to traffic jams and the growing lack of space in cities, cars are also ruining the urban landscape. The more cars pour into city centers, the less space there is for cyclists and pedestrians. Air traffic and rail transport are some of the biggest sources of noise. Noise pollution is also a cause of deterioration of people’s health. That is why efforts should be focused on building new, more environmental, sustainable and smart cities that motivate people to use public transport (Vasileva et al. 2022). First of all, we need to offer a high-quality public transport service that is accessible to all, so that people choose the bus or metro over their car. If traveling by car is more expensive, slower and inconvenient is also a good measure, but it may not work very well. On the other hand, the wider adoption of public transport would help reduce air pollution and free up space in urban areas, making urban traffic significantly more pleasant for cyclists and pedestrians, in addition to making cityscapes around the world more beautiful and calm (Nikolov et al. 2021). These problems require an urgent solution, because the number of private cars in cities cannot grow indefinitely, and thus, the harmful impact on the environment cannot continue to increase. One of the ways to prefer public transport over private transport is to improve its quality so that more people will start using it. So far, when planning the urban space, the priority has been driving comfort and providing maximum space for it (Vasileva et al. 2022). However, this has enormously increased the number of private cars in use and their negative impact on the environment. For this purpose, the principles of urban planning must be changed and priority should be given to the needs and comfort of people who use public transport and those who are pedestrians. In this way, more and more people will choose public transport and there will be a greater chance of saving the environment and the lives of future generations. This is one of the main goals of sustainable development. Public urban transport occupies an important place in the transport service of people. It must be fast, secure, accessible to all citizens and, last but not least, environmentally friendly. The future of this type of transport is entirely related to improving the quality of the transport services offered, increasing its social efficiency and environmental sustainability. Well-organized and regular urban transport is an extremely important prerequisite for the normal functioning of life in large cities, and the quality of transport services has a direct impact on the mental and physical health of citizens. Urban transport plays an extremely important role in the socio-economic development of cities and is a basic prerequisite for improving the quality of life of citizens. The importance of passenger transport for the development of the city has a social, economic, ecological and cultural aspect (Yordanov 2019). The social aspect is expressed through its direct influence on the standard of living of the population and its impact on people’s lives. Traveling in an urban environment often requires significant costs and a long time, which in turn reduces the time for rest, sports and satisfying cultural and household needs. The high quality of transport services

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provided by public transport is a prerequisite for increasing its social efficiency (Tzvetkova 2017). Enterprises working in the field of public transport must constantly make efforts to improve the quality of the transport services they offer in order to achieve maximum satisfaction of consumer requirements (Tzvetkova 2017). Thus, users will be satisfied and will prefer the possibilities of public transport over private cars. The object of research in our publication is the level of use of public transport in the city of Sofia. Sofia is the capital of Bulgaria, which is a member state of the European Union. On the one hand, Bulgaria is forced to fulfill the European requirements regarding the quality of the transport service. On the other hand, it is obliged to comply with international standards for environmental friendliness and sustainable development. For this reason, we will analyze the state of the transport fleet and its use by citizens in the city of Sofia. This will give us the opportunity for reasoned conclusions and further decisions to reduce the harmful impact of transport in order to achieve environmental sustainability of cities.

11.3 State of Public Transport in the City of Sofia for the Period 2020–2022 Public transport in the city of Sofia is carried out by all main types of transport— metro, bus, trolleybus and tram transport. It can be considered as a set of: transport communications with rolling stock; material and technical base for maintenance, repair and storage of vehicles; transport-service buildings and facilities, united by a comprehensive organization of the transport process and interrelated development of the technical base and others (Gatovski 2018). As Arnaudov (2021) writes, “the social dimension of urban passenger transport is related to establishing fair social conditions for all participants in the movement and increasing their quality of life” (Arnaudov 2021). The modernization of public transport and the improvement of the quality and accessibility of related services create a favorable environment and the possibility of moving in an urban environment without private cars for more people, which in turn is a step forward in establishing Sofia as a green city. The major commitment to which the main priorities for the development of the capital as a city with modern European transport are subordinated is a cleaner environment and improvement of air quality. With the modernization and overall improvement of the transport system, through the construction of transport connections between different modes of transport, more people will prefer to use public transport for their daily journeys. The caused by the pandemic crisis of the past three years has imposed new requirements on the services provided in urban transport. First of all, the preservation of the physical and mental health of the passengers had to be ensured. Indicators such as safety and security were imposed as a prerequisite to restore user confidence in the services provided by public transport. In response to the difficulties experienced

11 Improving the Quality of Public Transport to Achieve Environmental … Table 11.1 Main transport operators in the city of Sofia and their mileage (volume of work performed) in thousand km for 2020 and 2022

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Transport operators

2020

Stolichen Avtotransport EAD

35,385

2022 33,010

Stolichen Elektrotransport EAD

15,676

16,542

Metropolitan EAD

4692

5949

Other operators

7106

6 99

Total

62,861

62,300

Source Urban Mobility Center

during the crisis, cities and municipalities administered innovative and sustainable measures to overcome it more quickly (Yordanov 2019). Table 11.1 presents data on the annual route mileage of all operators in the city of Sofia. Despite the announced pandemic situation caused by COVID-19, in 2020 it did not decrease, and even increased for some operators. According to the volume of work performed in km (Table 11.1), it is clear that “Stolichen Autotransport” EAD has the largest share of the total mileage with over 33 million km annually. In second place is “Stolichen Elektrotransport” EAD with nearly 16.5 million km per year, followed by the other bus carriers with 6.8 million km and “Metropolitan” EAD with nearly 6 million km. One of the main measures that was taken as an anti-epidemic, both at the national level and in the city of Sofia, was not to change the schedules, respectively the number of vehicles on one line. All operators maintained their annual mileage (in km), for which corresponding operating costs were incurred, but with a large outflow of transported passengers, correspondingly lost revenue from sales for the companies. The main indicator for calculating the passenger flow on a given line or for each individual operator is the number of transported passengers. The data on transported passengers are based on sold one-time and subscription cards from the Center for Urban Mobility in the city of Sofia, for the period 2020–2022 (Table 11.2). In the specified data in Table 11.2. The number of transported passengers after the commissioning of the first 8 metro stations of the third metro diameter in 2020 and another 4 metro stations in 2021 by the Metropolitan EAD are also included. Table 11.2 Number of passengers transported by individual modes of transport, for the period 2019–2022 Transport operators

2019

2020

2021

2022

Subway

224,815,770

172,165,533

186,160,601

238,236,577

Tram

97,837,284

79,798,984

73,544,160

92,011,380

Trolleybus

42,232,618

28,248,933

26,717,629

38,292,956

Bus

223,730,437

154,353,076

141,686,685

144,270,333

Total

588,616,109

434,566,526

428,109,075

512,811,246

Source Urban Mobility Center and author’s calculations

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For 2019 (the year before the commissioning of the third metro diameter), the metro carried a total of 224,815,770 passengers. In 2020, when the real health crisis began, the decline in the consumption of the service (in a downward trend) is also clearly noticeable, namely, 172 million passengers were transported by metro, the decrease is 24% compared to 2019. The data for 2022 show that the number of passengers carried by the metro in the capital has recovered and reaches over 238 million passengers per year. 800 million passengers were transported by tram transport in 2020 compared to 98 million in 2019. The total decrease for this type of transport on an annual basis in 2020/2019 is 18.44%. In 2022, there was almost a recovery of pre-Covid crisis levels and just over 92 million passengers were transported. The total reflection in the number of transported passengers for trolleybus transport is -33.11% on an annual basis (2020/2019). In 2022, 38 million passengers were transported, an increase of nearly 10 million passengers per year compared to 2020. In absolute and percentage terms, the biggest impact of the pandemic is on the transportation of passengers by bus transport. On an annual basis, the decrease in transported passengers served by bus transport is over 31.01% (2020/2019). Although at a slower pace, there is an increase in the number of transported passengers for 2022 compared to 2021. The total decrease in the number of passengers carried for 2021 compared to 2019 is 27%, from 588,616,109 to 428,109,075 passengers. In 2022, the levels from before the Covid pandemic were restored and 512,811,246 passengers were transported. Compared to 2021, they are nearly 85 million more. The analysis of the data shows that the citizens of the capital of Bulgaria are starting to restore their trust in public transport and its use is starting to recover to the levels of the pre-crisis period. Also of interest are the measures to increase the quality of the service in public transport, which actually leads to its sustainable use and this, in turn, leads to a reduction in the harmful effects of transport and an improvement in environmental indicators.

11.4 Measures for Improving the Quality of Public Transport in an Urban Environment The restoration of the high share of the number of passengers carried and the distance of the transport can only be realized with better competitive advantages of the transport operators over the alternative methods of movement in the urban environment. The most important economic factors for increasing the competitiveness of transport companies are increasing the quality of transport services and reducing the costs of carrying out the transport activity (operating costs in the company). Cost reduction enables the company to offer competitive vehicle prices. The other main factor, namely the increase in the quality of transport services, is a necessary condition for attracting more passengers. These prerequisites will provide an opportunity to carry

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out a larger volume of transports, and thus also to realize larger revenues (Gatovski 2012). The quality of the transport service is characterized by indicators such as: regularity and timeliness of the transports, improvement of amenities and comfort during the travel of the population, speed, security and safety. The use of intelligent transport systems makes it possible to improve traffic safety by shortening the deadlines for the implementation of administrative procedures. International experience shows that in the management of companies in the field of urban bus transport, measures to improve electronic billing, fleet management, providing information to passengers, giving priority at intersections regulated by traffic lights, etc., can give significant results in in terms of increasing the number of trips (passengers) by public transport. After the COVID-19 pandemic, European cities, including the city of Sofia, have had to work even harder to create areas where citizens can move around in a sustainable and safe way whenever they want. Anxiety during travel due to large groups of people or insufficient travel information has somewhat lost the confidence of passengers in public transport. That is why enterprises working in the field of public transport must strive to create a prerequisite for sustainable mobility, reducing the risk of social exclusion and a fulfilling lifestyle for citizens. They must ensure, above all, the preservation of people’s mental and physical health, security and comfort during the trip. The crisis caused by the COVID-19 pandemic had a negative impact on public transport in the city of Sofia. At the beginning of 2020, it recorded a decrease in the carried out shipments, compared to 2019, by 26.17%, and in 2021, compared to the previous year 2020, by 1.49%. The significant reduction in passenger traffic was primarily due to concerns about the risk of contracting the virus on public transport. In order to overcome the negative consequences of the pandemic more quickly, it is necessary, first of all, to restore the trust of users in the services provided by public transport. For this purpose, it is necessary to raise the quality of the offered transport services to the necessary level, which would satisfy the passenger’s requirements as much as possible, regarding reducing the travel time and preserving their physical and mental health, as well as guaranteeing security, safety and comfort during travel. In order to quickly restore consumer confidence in the services provided by public transport, it is necessary to increase the quality of the transport services offered. The development of a subway in Sofia is an important tool in the overall improvement of the transport system and for the implementation of the concept of creating sustainable urban mobility. The construction of a new metro diameter, with the phased introduction of the metro stations connected to it, will redirect a significant part of the passenger flow from the existing ground public transport /with tendencies to continue this process in the future development of the metro network/. The whole process necessitates the creation of a strategy for transport leading to the lines of the urban railway, as part of the construction of a more efficient transport chain. With the implementation of a project for the purchase of 52 electric buses, the transport system in Sofia was completely improved and parts of the route network

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were optimized. The purpose of the majority of electric buses /30 + 5 operational reserve/ is to serve three of the main large districts in the capital, contributing to: • Development of the transport system in line with the requirements for attitude to the environment and climate; • Reduction of harmful emissions and fine dust particles from the operation of vehicles; • Improving the quality of the transport service by renewing the fleet with means of transport with high environmental standards; • Increasing the coordination and integration of individual types of transport; • Provision of accessible urban transport in neighborhoods with poorly developed transport network and/or transport infrastructure; • Ensuring convenience for citizens, reducing traffic and congestion and shortening travel time; • Increase in the share of trips by public transport. In order to improve the quality of public transport and mobility in the city of Sofia, the following measures can be taken: • Choosing a rational route system—one of the most important issues for achieving a good organization of urban passenger transport, which depends on reducing travel time and generally improving the quality of the transport services offered. Studying the directions of passenger flows and factoring them into routing can reduce travel times and minimize the transfer of passengers from one route to another. This requirement is of primary practical importance, as it reflects the need to ensure fast and comfortable travel by mass urban passenger transport. • Introduction of an accelerated mode of movement of vehicles, which implies the cancellation of a part of the stops along the route. This ensures an increase in the operational speed of urban passenger transport, which is important both for reducing travel time and for accelerating the turnover of vehicles. • Renewal of the rolling stock of public transport—the most radical and fastest way to reduce the harmful emissions of bus transport in the city of Sofia is the commissioning of new buses with better environmental performance, based on new or improved technological solutions. • Implementation of Intelligent Transport Systems in the organization of the city transport system. In order to improve safety and security and to ensure regular and reliable transport in the city of Sofia, in addition to the introduction of modern rolling stock, it is necessary to remove even the smallest prerequisites for the occurrence of accidents and traffic accidents on the city’s streets. For this purpose, first of all, effective organization and management of the transport process must be ensured. Effective management includes building optimal connections and high coordination between different types of urban transport, as well as the implementation of Intelligent Transport Systems in the organization and management of urban passenger transport. These systems use information and communication technologies to collect

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and process data on transport and to support the decision-making process, as well as to evaluate the effects of transport projects (Nikolova and Klisurova 2015). • Improving the information about the movement of public transport. In order to promptly prevent possible violations in the regularity of the movement of vehicles, the operation services in the mass passenger transport system must systematically study and reveal the reasons causing these violations on each specific route (Nikolova and Klisurova 2015).

11.5 Conclusion EU transport policy is aimed at achieving sustainable urban mobility and environmental sustainability of the transport fleet and transport infrastructure. In this regard, it is necessary to develop an integrated, socially effective and high-quality public transport that can be used by the maximum number of citizens. To this end, first of all, the use of private vehicles should be limited and the use of public transport that is ecological, sustainable, safe and accessible should be encouraged. The European Green Package supports the recovery after pandemic crisis by helping to build a more sustainable ane environmental friendly EU economy. In order to more quickly overcome the negative consequences of the pandemic crisis and return to its normal functioning, public transport in the city of Sofia must offer transport services that guarantee the preservation of people’s health and at the same time be of high quality and accessible services for all citizens. In conclusion, we can say that the crisis as a result of Covid-19 strongly affects and continues to leave its deep imprint on the transport sector, including urban transport by public transport. Restoring the high share of the number of transported passengers before the Covid crisis and the average distance traveled by public urban transport can only be realized with high security and an increase in the quality of services offered by transport carriers. The most important economic factors for increasing the competitiveness of the transport company are increasing the quality of the transport service and reducing the costs of carrying out the transport activity (operating costs in the company). For the period under review, these costs have maintained, even increased in a certain value due to the fact that one part of the anti-epidemic measures was to preserve the mileage of the vehicles serving the city lines. Nevertheless, the crisis made it possible to replace part of the rolling stock with electric ones, which led to a reduction in harmful emissions from vehicles in the city of Sofia. The quality of transport services of public transport must be continuously improved, which will lead to its fuller use by citizens. Only in this way can long-term ecological sustainability of the urban environment be achieved.

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References Arnaudov B (2021) Road safety of vulnerable participants in traffic—current states and directions for improvement. Scientific works of UNWE (3) 2021, Publishing complex—UNWE. http://unwe-researchpapers.org/uploads/ResearchPapers/RP_vol3_2021_ No09_B%20Arnaudov_Rcd.pdf. Last Accessed 28 Mar 2023 Gatovski I (2012) Increasing the competitiveness of road transport through the development of the national road infrastructure. Publishing complex—UNWE Gatovski I (2018) Guidelines for increasing the quality of transport services in the transportation of passengers in an urban environment. Scient J: Mech Transp Commun 16(3/1):1610 Nikolov G, Vasileva E, Botseva D (2021) Methodological aspects of strategic regional planning for achieving sustainable development in Bulgaria. https://doi.org/10.1007/978-3-030-752781_28. In: 4th International conference on sustainable development of water and environment, ICSDWE 2021 Bangkok, 12 March 2021 through 13 March 2021. Retrieved from www.scopus. com Nikolova H (2015) Evaluation of the costs and benefits of the implementation of intelligent transport systems in Bulgaria. MTC-aj.com—Scient J Scientific Report ID 1167: 2015/3 Nikolova H, Klisurova M (2015) Intelligent transport systems in an urban environment. Sofia, Publishing complex—UNWE Ridango (2023) Five reasons why using public transport is better for the environment. Retrieved https://ridango.com/five-reasons-why-using-public-transport-is-better-for-the-enviro nment/. Last Accessed 27 June 2023 Tzvetkova S (2017) Reducing the harmful impact of urban passenger transport on the environment. Managem Sustain Developm 4/2017(65):56–72 Vasileva E, Lyubomirova V, Tsolov G (2022) Sustainable cities via smart development strategies: Bulgarian case. https://doi.org/10.1007/978-3-031-07500-1_24. In: 5th International conference on sustainable development of water and environment, ICSDWE 2022. Virtual, Online17 March 2022 through 18 March 2022. Retrieved from www.scopus.com Velikova E (2021) Sustainable environmental planning of a tourist destination Bulgaria—State and trends. https://doi.org/10.1007/978-3-030-75278-1_22. In: 4th International conference on sustainable development of water and environment, ICSDWE 2021 Bang-kok12 March 2021 through 13 March 2021. Retrieved from www.scopus.com Yordanov D (2019) Consumer assessment of the quality of transport services and guidelines to increase their competitiveness. Econ Alternat 2019(4):571–581 Yordanov D (2022) Pre-pandemic and post-pandemic state of the transport industry in Bulgaria, as a result of COVID-19. Round table: “The plan for development and sustainability—challenges for higher education and science. 02–04.12.2022, Arbanasi village

Chapter 12

River Healthy Assessment in Developing Countries—A Case Study on Yellow River Yuansheng Zhang, Zhiwei Cao, Xin Jin, and Guojie Liang

Abstract With the rapid economic development of developing countries, river ecosystems are constantly being disturbed and damaged by human activities, and maintaining the healthy life of rivers has received more and more attention. This paper, taking the Yellow River as an example, conducts study to provide new technical support for river governance in developing countries. Since the people ruled the Yellow River, they have achieved world-renowned achievements in its governance, development and protection. However, the ultimate goal of maintaining a healthy life in the Yellow River is facing new challenges. By adopting classic theories such as system theory and information theory, this study optimizes the river health assessment system based on the River Health Index (RHI) through in-depth analysis of the health quality of the Yellow River’s life system and its own stability, to provide technical support and theoretical basis for the protection and governance of the Yellow River Basin. The study finds that the overall evolution of RHI is firstly decreasing and then increasing, showing an oscillating upward trend; the total scouring and silting volume (the lower reaches of the Yellow River), the change rate of estuary wetland area, the guarantee rate of ecological base flow of important sections, and the discharge capacity of the main channel (Ningxia-Inner Mongolia Section) are the key factors affecting the healthy life system of the Yellow River. Keyword Yellow River healthy life · Information entropy · Yellow River health index · Dissipative structure

Y. Zhang North China University of Water Resources and Electric Power, Zhengzhou, China Y. Zhang · Z. Cao (B) · X. Jin · G. Liang Yellow River Engineering Consulting Co. Ltd, Zhengzhou, China e-mail: [email protected] Key Laboratory of Water Management and Water Security for Yellow River Basin of Ministry of Water Resources, Zhengzhou, China © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_12

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12.1 Research Background The Yellow River is the second largest river in China (Fig. 12.1), with a total length of 5464 km and drainage area of 795,000 km2 . The Yellow River Basin spans the three major regions of the east, middle, and west of the country and constitutes an important ecological barrier in China. It is an ecological corridor connecting the Qinghai–Tibet Plateau, Loess Plateau, and North China Plain, and plays an important role in ecological security. The Yellow River flows through nine provinces (regions), and its upper reaches include Qinghai, Sichuan, Gansu, Ningxia, and Inner Mongolia. The middle reaches included Shaanxi and Shanxi. The downstream areas included Henan and Shandong. At the end of 2019, the total population of the nine provinces in the basin was 450 million, accounting for about 32% of the country’s total population; the regional GDP was 23.9 trillion yuan, accounting for about 24% of the country’s total. It is an important economic zone and energy base in China. As river ecosystem continues to be disturbed and damaged by human activities, scientifically and effectively assessing, restoring and maintaining a healthy river ecosystem has become an important goal of river basin management in recent years (Karr 1991; Karr and Chu 1998; ASCE 2003; Voro smarty et al. 2010; Muqi and Yuyao 1998; Fubo et al. 2007; Zheren 2005; Poff et al. 1997; Jinren and Yuanyuan 2006a, b; Dongya et al. 2006; Wang et al. 2019). In this context, river health is a completely new concept that emerged in the twentieth century, and related theoretical researches and evaluation practices have developed rapidly. The theory and methods of river health assessment aim to fully understand and comprehensively evaluate the river’s hydrology, biology, habitat and other conditions from the perspective of the river ecosystem as a whole (Xuelan and Chunhong 2007; Raven et al. 1998; Parsons et al. 2002; Roux 2001; Zhao et al. 2019; Luo et al. 2018), so as to provide basic

Fig. 12.1 Distribution of the main basins of the Yellow River

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data and information feedback for the adaptive management of rivers, and promote the healthy and sustainable development of rivers. This has become a hot issue in international river management research (Tao et al. 2002; Yanwei and Zhifeng 2005; Shijie et al. 2019). Maintaining a healthy river life is the ultimate goal of the Yellow River governance (Guoying 2004). Since the people ruled the Yellow River, great changes have taken place in the economic and social development of the Yellow River Basin and the lives of the people, but there are still some outstanding problems, such as the fragile ecological environment of the river basin, frequent water disasters in some areas, and the severe situation of water resources security. After the 1990s, the health problems of the Yellow River became more prominent (Yiming et al. 2005; Jiangyan 2020; Siyuan et al. 2004; Hongwu 2020; Jinliang et al. 2020; Zhongmin and Hongbin 2004; Haiying and Suocheng 2002). In response to the problems of the Yellow River, Li Guoying proposed a new river governance concept of “maintaining the healthy life of the Yellow River”, and put forward the connotation of the healthy life of the Yellow River from the perspective of river ethics: water and sediment conditions can basically meet the normal needs of river ecosystem, and at the same time can basically guarantee human life production and economic and social development. With the further reduction of water and sediment in the Yellow River in recent years, the boundary conditions of the Yellow River channel have undergone major changes. With the rapid economic development of the areas along the Yellow River, maintaining the healthy life of the Yellow River and promoting the harmony between people and water in the basin have become one of the important research issues in river governance. Starting from the requirements of high-quality development of water conservancy in the new era, this paper uses classic theories such as system theory and information theory to select key indexes representing river health to deeply analyze the cyclic evolution of key elements in the Yellow River life community, construct a positive and negative feedback mechanism based on respecting the value of the river and maintaining the power of river survival, quantitatively study the stability (self-recovery ability) of the river’s life system, optimize the river health assessment system based on River Health Index (RHI) for decision-making, and provide technical support and theoretical basis for the protection and governance of the Yellow River Basin.

12.2 Healthy Life of the Yellow River in the New Era The Yellow River is the mother river of the Chinese nation. It is the responsibility and obligation of children to maintain the health of mothers. Since the people ruled the Yellow River, they have made world-renowned achievements in the governance, development and protection of the Yellow River, and achieved significant economic, social and environmental benefits in water and sediment management, ecological protection, flood control and disaster alleviation, water and soil loss control, and water resources utilization, which have strongly supported the sustainable economic

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and social development of the river basin (Chunhong 2015; Xiandi and Xiaohua 2016; Chunhong and Xiaoming 2018; Kaizhong and Yaning 2020; Yue et al. 2015; Renqiong and Qinye 1996; Peiguo et al. 2006; Weihua et al. 2020; Bingyan and Songgui 1998; Caizhi et al. 2020; Qiting et al. 2020; Jinliang 2020; Guoying 2003). However, the Yellow River is a river that is prone to siltation, bursting and diversion. The unbalanced relationship between water and sediment determines the long-term, arduous and complex nature of the Yellow River governance work. How to maintain the healthy life of the Yellow River is a problem that we should think about deeply in the context of the high-quality development of water conservancy in the new stage. In life science research, the concept and meaning of river life is modern and broad. Starting from river ethics, researchers endow rivers with three basic characteristics (Guoying 2003; Jinliang et al. 2020): (I) The river is alive. Macroscopically, the river is a composite open system, consisting of many subsystems and key elements, and this embodies the three basic functions of material circulation, energy flow and information transmission in the process of life movement. Taking the Yellow River as an example, the life system of the Yellow River is a complex giant system, including rivers, lakes, forests, grasslands, wetlands, deserts, Gobi and other rich ecological environmental elements. These elements in the system continue to carry out material circulation and energy flow, playing an important role in maintaining the healthy life of the Yellow River. They also constitute an important ecological barrier in our country, as an ecological corridor connecting the QinghaiTibet Plateau, the Loess Plateau and the North China Plain, occupying an important position in our country’s ecological security. (II) Rivers are valuable. Rivers have natural value and intrinsic value. Only by establishing the status of the river as the subject of value, can the value orientation of anthropocentrism be changed. The Yellow River is the mother river of the Chinese nation and the cradle of Chinese civilization. It not only nurtures Chinese civilization, but is also an important ecological barrier and an important economic zone in our country, with important missions to ensure national ecological security, food security, flood control security and drinking water security. At present, human beings pay more attention to the process of governance, and even indulge in the joy of completely conquering the river. However, human beings have also suffered from nature’s revenge, and a series of riverrelated black rhino and black swan incidents have become increasingly serious (Peiguo et al. 2006; Weihua et al. 2020). Mankind should maintain the dignity and value of the river, establish a scientific positive and negative feedback mechanism, completely change the relationship between the subject and the object of value between men and river, and achieve human-water harmony. (III) Rivers have basic rights and functions. The value of the river itself determines that the river has many rights. The most basic right is the right to survive. At the same time, humans should respect the integrity and continuity of the river, as well as its right to maintain clean water, basic water volume and nurture the growth of all things in the basin. On the premise of satisfying the rights

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of rivers, rivers should have stable channels, moderate flooding, clean water quality, healthy basin ecosystems and continuous creation capabilities. On the whole, to maintain the healthy life of the Yellow River and promote the harmony between people and water in the basin, it is necessary to break the traditional river governance mode of “treating only where the pain is”, and transform the governance concept of the Yellow River from “people-centered” to “river life-centered”. We must take river health as the goal, thoroughly study the river healthy assessment system, properly handle the relationship among rivers, ecology and humans, and jointly provide important support for the ecological conservation and high-quality development of the Yellow River Basin.

12.3 Methodology 12.3.1 River Health Index (RHI) River Health Index (RHI): one of the three subsystems (river, ecological environment and social economy) under the framework of Basin Development Index (BDI) based on previous research results, which gives a comprehensive analysis of flood, sediment, water resources and other related factors to evaluate the health of the river system (Guangqian and Yuan 2007) from the perspective of river healthy development. The RHI of the Yellow River Basin covers the information of various river health factors, and can represent the overall health of the Yellow River (Ziyun 2000; Yongsheng and Hao 2007; Yongsheng et al. 2022; Xiaoyan et al. 2006; Changming and Xiaoyan 2008; Xiaoyan and Yuanfeng 2006; Norris and Thoms 1999; Karr 1999; Scrimgeour and Wicklum 1996; Schofield and Davies 1996; Jianguo 1991). In this paper, RHI is used to characterize the river health, it is a comprehensive evaluation index based on entropy and dissipative structure, representing the uncertainty of comprehensive river health indexes and the development state of the system. The larger the RHI value, the healthier the river, the higher the quality of development, and the stronger the ability to resist interference and the ability of transition to a higher state; the smaller the value, the more fragile the health of the river, the low active ability, and the poorer anti-interference ability, with a certain risk, and it is necessary to strengthen supervision and take certain measures for governance.

12.3.2 Entropy Model The Yellow River is a complex giant system with numerous elements. In order to quantify the three basic functions of material circulation, energy flow and information transmission during the movement of the Yellow River’s life system, the concept and calculation method of entropy in the classical information theory are introduced to

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conduct quantitative research on the amount of information and order (degree of chaos) of these numerous elements in the Yellow River’s life system. Information entropy can not only characterize the circulation of complex elements in the Yellow River’s life system, but also construct a positive and negative feedback mechanism to provide a reference for studying the state and stability of the river’s life system. The state of the Yellow River’s life system depends on two aspects, internal and external: one is the positive entropy flow generated by the irreversible process of the survival and development of the giant system in the basin; on the other, the life system of the Yellow River is like an organism. If it wants to maintain a healthy, sustainable and orderly development trend, or make a transition to a higher-quality development state, it must obtain an effective negative entropy flow from the external environment, that is, the exchange of information, material and energy between the natural river and the external environment is constantly being carried out (Nanshan and Tianxiang 1988; Guobin and Lina 2017). The calculation steps of entropy weight and positive and negative entropy model are as follows: (1) Calculate the entropy and weight of each index S=−

n 1  ( pk lnpk ) ln n k=1

fk p k = n i=1

wi =

(12.1)

(12.2)

fi

1 − Si N N − i=1 Si

(12.3)

where, n represents the number of standard intervals of the index value, pk represents the proportion of each standard probability function value in all values f k , S represents the entropy value, and wi represents the weight of the index i. (2) Calculate the positive and negative entropy values A=

N  

Si, A ∗ wi, A



(12.4)

i=1

B=

N  

Si,B ∗ wi,B



(12.5)

i=1

where, A and B represent the sum of positive and negative entropy changes of the system respectively, and N is the corresponding number of index.

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12.3.3 Brusselator Model The River Health Index (RHI) means that the health of the river life system depends not only on the level of high-weight indexes, but also on the stability of the system. Stability has two meanings: one is the self-recovery ability of the system, which means that the healthier a river is, the stronger anti-interference ability or selfrecovery ability it has; the other is the system’s transition ability to a higher level (or a steadier state). The steady state of the river life system (steady state) is maintained by positive and negative feedback adjustments. A certain amount of negative entropy flow needs to be introduced to maintain the steady state, and the system state transition is driven by positive and negative feedback. The steady-state transition will only occur when external conditions continue to change in a certain direction (such as continuous governance measures). Figure 12.2 describes the steady-state transition process of the river life system intuitively. In the figure, the small ball represents the system, the peak position represents the critical value of steady-state transition, and the trough position represents different steady state. The system fluctuates under the influence of disturbance. When the disturbance is the driving force to make the system reach the critical value (peak) of steady-state transition, the system may balance at another steady-state position. The size of basin (groove) attracting the small ball in the figure is also called system toughness. The stronger the toughness is, the stronger the self-recovery ability of the river life system possesses. Figure 12.2 illustrates the complexity of the river life system. Its internal components have the characteristics of non-linear correlation, the fluctuation characteristics of the system state, and the internal temporal and spatial heterogeneity of the system (Xiandi and Xiaohua 2016). The system can be considered as a complex system of a kind of dissipative structure (Roux 2001), which satisfies the characteristics of open dissipative structure, far from equilibrium, nonlinearity, fluctuation and sudden change. Therefore, the theory of dissipative structure can be used to study the dynamic mechanism of the river life system and quantify the driving force of steady-state transition within the system.

Fig. 12.2 Steady-state transition diagram of system

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The Brusselator Model is a mathematical model put forward by Ilya Prigogine, which can quantitatively analyze the dissipative structure. Jianxia et al. applied it to the complex system of water resources after escaping, to study the influence and evolution analysis of the changes of internal and external factors of the complex system of water resources on the overall status of the system (Tienan et al. 2010; Dongshan et al. 2013, Chen et al. 2015, Xianzeng et al. 2021, Jianxia et al. 2002). Similarly, we can divide the life system of the Yellow River Basin into two parts: the internal system (the background situation of the river itself) and the external influence (river basin governance, policy mechanism, management measures, etc.), and escape the parameters in the Brusselator Model. The internal positive entropy flow of the system is a disorder-based cause. If there is no negative entropy inflow, the internal positive entropy will increase, and the system will develop into disorder; the external negative entropy flow is the key to the stability of the system, or the driving factor of the system state transition (to a higher or more stable state). The Brusselator Model can be described as: A K1 X − → B + X K2 Y + D − → Y + 2X K 3 3X − → X K4 E − →

(12.6)

After the escape, the model parameter A represents the positive entropy flow (internal factor of the river life system), B represents the negative entropy flow (external influence on the river), and D represents the low dynamic state of system steady-state transition under the positive and negative entropy flow interaction, E represents the high dynamic state of system steady-state transition under the positive and negative entropy flow interaction, X represents the quantifiable factor of the system positive entropy flow index system, and Y represents the quantifiable factor of the system negative entropy flow index system. According to the Brusselator’s equation and inference, when |B| > 1 + A2 , the system can become a dissipative structure. For the system, the following formula can be used to judge the driving force of the steady state of the system: ⎧ ⎨ < 0, System steady − state trasition power.low |B| − (1 − A2 ) = 0, Critical value of system steady − state trasition ⎩ > 0, System steady − state trasition power.high

(12.7)

When the value of |B| > 1+ A2 is equal to 0, it reaches the critical state of steadystate transition, that is, the peak position in Fig. 12.1, and is ready for transition to a new steady-state; when the value is less than 0, the system is always in a nondissipative structure, that is, a stable thermodynamic branch. The river basin system does not have the “intelligence” of self-organization, and has poor resistance to

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external interference. After being disturbed, it can only follow the trend and cannot self-regulate. Eventually, the system development will tend to be disordered; on the contrary, when the value is greater than 0, the system will undergo a transition and enter a dissipative structure state. The river basin system can resist adverse interference generated by the outside world through a dynamic self-organization process, and maintain a high-level and orderly state at all times. The RHI calculation steps are as follows:   I ndex DS = |B| − 1 + A2

(12.8)

R H I = 100 ∗ (I ndex DS + 2)/3

(12.9)

I ndex DS is a dissipative structure index calculated by the Brusselator Model. Considering the principle of easy promotion, this study uses a percentile system to assign RHI points. When calculating the score, the value range of the dissipative structure index is linearly converted to the interval [0, 100] to obtain the conversion formula in Formula (12.8), when I ndex DS is 0, that is, when the system reaches the threshold value of the dissipative structure, the RHI is assigned a score of 66.7 points.

12.3.4 Index System From the five abilities that a healthy river life should have (1. The ability of the water cycle to operate normally; 2. The ability to safely discharge a certain level of flood; 3. The ability to supply water resources; 4. The ability to function well in the river ecosystem; 5. The ability to carry a certain degree of pollution) (Guoying 2004), aiming at the new stage of the Yellow River Basin ecological conservation and highquality development of water conservancy to meet the four goals of improving flood control and disaster mitigation capabilities, water supply security capabilities, river and lake health protection capabilities, and modern water governance capabilities, the comprehensive evaluation index system of the Yellow River healthy life is constructed as shown in Table 12.1 based on the principles of systematicness, comprehensiveness, typicality, quantification and accessibility.

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Table 12.1 Comprehensive evaluation index system of the Yellow River healthy life SN Target layer Criterion layer Index

1

River

Sediment situation

Unit

Coordination degree of incoming flow and sediment

Positive Polarity Data source or negative entropy Positive entropy

−1

Water year book

2

Quantity of incoming sediment

100 Positive million entropy m3

−1

Water year book

3

Total scouring 100 Positive and silting million entropy volume m3 (Ningxia-Inner Mongolia Section)

−1

Hydrographic office

4

Total scouring 100 Positive and silting million entropy volume (lower m3 reaches of the Yellow River)

−1

Hydrographic office

Total water 100 Positive volume million entropy (Huayuankou) m3

1

Water year book

6

Total water volume (Toudaoguai)

1

Water year book

7

Flood capacity m3 /s of the main channel (Ningxia-Inner Mongolia Section)

Positive entropy

1

Yellow River Ice Prevention Plan

8

Flood capacity m3 /s of the main channel (lower reaches of the Yellow River)

Positive entropy

1

Analysis report on flood discharge capacity of the lower Yellow River channel

9

Water consumption rate

Positive entropy

−1

Calculated based on water consumption

5

Hydrological situation

100 Positive million entropy m3

%

(continued)

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Table 12.1 (continued) SN Target layer Criterion layer Index

Unit

Positive Polarity Data source or negative entropy

10

km2

Negative 1 entropy

Water statistics bulletin

Ecological Environmental Management area of the environment factor Loess Plateau

11

Qualification % rate of water quality in important water function zones

Negative 1 entropy

China water resources bulletin

12

Proportion of river length with Class III and above water quality in important tributaries

%

Negative 1 entropy

China water resources bulletin

13

Total annual rainfall

mm

Negative 1 entropy

Sum of annual precipitation in nine provinces along the Yellow River

Guarantee rate % of ecological base flow of important sections

Negative 1 entropy

Cross section hydrological data

15

Habitat quality index

Negative 1 entropy

Calculated from land use spatial dataset

16

Change rate of % wetland area in river source area

Negative 1 entropy

Interpretation based on Landsat satellite remote sensing images

14

Ecological factor

(continued)

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Table 12.1 (continued) SN Target layer Criterion layer Index

Unit

Positive Polarity Data source or negative entropy

17

Change rate of % wetland area in Ulansuhai Nur

Negative 1 entropy

Interpretation based on Landsat satellite remote sensing images

18

Change rate of % estuary wetland area

Negative 1 entropy

Interpretation based on Landsat satellite remote sensing images

12.4 Result Analysis 12.4.1 RHI Value Figure 12.3 is the change trend chart of the Yellow River Health Evaluation System, which shows the evolution of the health status of the Yellow River in the past 40 years. The average score is 64.56, the lowest score is 59.12 in 1994, and the high scores are 69.95 in 1981 and 72.18 in 2019, with an overall trend of decreasing first and then increasing. Before 1985, China was in the early stage of reform and opening-up, the negative impacts on the ecological environment of rivers by human activities were limited, RHI was developing for the better, and the river life system was relatively healthy. After 1985, the volatility of RHI declined and reached its lowest stage around 1994–1999. At this stage, the economic development level of the river basin has gradually improved. However, due to economic development, insufficient attention was paid to the protection of ecological environment and the maintenance of the carrying capacity of the river basin, coupled with the frequent occurrence of river drying-up and floods, resulting in poor river life system. After 1999, although development volatility still existed, due to the positive influence of scientific decision-making, systematic governance and major projects in the basin, the overall development trend of the basin system was improving. The RHI index reached a historically high value of 72.18 in 2019.

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Fig. 12.3 RHI changes from 1980 to 2019

12.4.2 Feedback Mechanism and System Transition Force From Table 12.2 and Figs. 12.4 and 12.5, it can be seen that the overall change trend of the steady-state transition force value of the river healthy life system from 1980 to 2019 is similar to that of RHI, and the overall trend is decreasing first and then increasing. After 2000, as the positive entropy flow continued to weaken and the negative entropy flow (absolute value) gradually increased, the system transition showed an oscillating upward trend. In the past five years, the transition force of the system has gradually increased, reaching the state of dissipative structure in 2017, 2018 and 2019 respectively, but the values are relatively low with certain volatility and retracement. It shows that the impact of negative entropy flow needs to be continuously strengthened, that is, continuous river basin governance, policy mechanisms, management measures, etc., to provide support for the system to maintain stability, enhance anti-interference ability, or transition to a more stable and advanced state.

12.4.3 Criterion Layer Figure 12.6 shows the contribution of the composite indexes of the criterion layer to the RHI. The greater the contribution, the more sensitive the index, and measures need to be taken to manage or strengthen supervision. In general, environmental factors and ecological factors have always had a great impact on RHI; while hydrological factors have a relatively small impact during 1980–1990, the contribution has remained high from 1990 until 2015, and it has somewhat declined after 2015; This is mainly due to changes in the flood discharging capacity of the Ningxia-Inner Mongolia Section and the main channel of the lower reaches of the Yellow River, which are the main impact

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Table 12.2 The positive entropy flow, negative entropy flow and steady-state transition force value of healthy life system of the Yellow River from 1980 to 2019 Year

Positive entropy flow

Negative entropy flow

System transition force

Year

Positive entropy flow

Negative entropy flow

System transition force

1980

0.31

−1.05

−0.05

2000

0.32

−0.95

−0.16

1981

0.28

−1.18

0.10

2001

0.37

−0.95

−0.19

1982

0.19

−1.13

0.09

2002

0.38

−0.96

−0.18

1983

0.22

−1.12

0.07

2003

0.35

−1.02

−0.10

1984

0.16

−1.11

0.08

2004

0.34

−1.05

−0.07

1985

0.25

−1.04

−0.02

2005

0.31

−1.08

−0.02

1986

0.27

−1.05

−0.02

2006

0.33

−1.06

−0.04

1987

0.32

−1.07

−0.04

2007

0.31

−1.00

−0.10

1988

0.36

−1.10

−0.04

2008

0.30

−0.92

−0.18

1989

0.30

−1.11

0.01

2009

0.26

−0.96

−0.10

1990

0.31

−1.13

0.04

2010

0.30

−0.98

−0.11

1991

0.38

−1.03

−0.11

2011

0.26

−0.96

−0.11

1992

0.45

−0.99

−0.21

2012

0.29

−0.97

−0.11

1993

0.37

−0.98

−0.16

2013

0.28

−1.03

−0.05

1994

0.45

−0.98

−0.23

2014

0.28

−1.11

0.03

1995

0.44

−1.01

−0.18

2015

0.31

−1.11

0.01

1996

0.46

−1.02

−0.19

2016

0.33

−1.10

−0.01

1997

0.43

−1.15

−0.04

2017

0.32

−1.15

0.05

1998

0.41

−1.02

−0.15

2018

0.32

−1.11

0.01

1999

0.41

−0.95

−0.22

2019

0.24

−1.22

0.17

index of the hydrological subsystem: Before 1990, the river channel siltation of the two wandering sections was relatively serious. After 1990, due to artificial water and sediment regulation, especially after Xiaolangdi was put into operation, the flood discharging capacity of the main channel of the lower reaches of the Yellow River was significantly improved. After 2015, it has been relieved, mainly because the water and sediment regulation of Xiaolangdi must take into account the opposition between the siltation of the reservoir itself and the siltation of the river channel. The contribution of the sediment situation to the river health system is as follows: the contribution increased year by year between 1980 and 1995, mainly due to the gradual use of upstream reservoirs, which reduced the amount of siltation in the Ningxia-Inner Mongolia Section, and then fell to the lowest point in the following ten years, mainly due to the serious soil erosion and unfavorable water and sediment conditions in the middle reaches, which led to excessive sediment entering the lower reaches of the Yellow River; after 2005, due to the operation of Xiaolangdi Project, the amount of sediment entering the lower reaches of the Yellow River had a sharp decrease, resulting in an increase in the contribution of this time period.

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Fig. 12.4 Changes in the positive and negative feedback mechanism (Entropy Flow) from 1980 to 2019

Fig. 12.5 Changes in the transition force of the river healthy life system from 1980 to 2019

12.4.4 Critical Index Statistics are made on each high-weight index in the comprehensive evaluation system for the development quality of the Yellow River Basin, and the results are shown in Table 12.3. During the past 40 years, in the evaluation index system, the most frequent indexes with the highest weight are: total scouring and silting volume (the lower reaches of the Yellow River) (12 times), with the probability accounting for 30%; change rate of estuary wetland area (6 times), with the probability accounting for 15%; guarantee rate of ecological base flow at important cross Sections (6 times), with the probability accounting for 15%; and discharge capacity of the main channel

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Fig. 12.6 Contributions of different criterion layers of the river healthy life system from 1980 to 2019

(Ningxia-Inner Mongolia Section) (5 times), with the probability accounting for 12.5%. The top three weights with higher frequency are: guarantee rate of ecological base flow at important cross Sections (25 times), with a probability ratio of 62.5%; total scouring and silting volume (the lower reaches of the Yellow River) (19 times), with a probability ratio of 31.7%; change rate of estuary wetland area (11 times), with a probability ratio of 27.5%; and discharge capacity of the main channel (Ningxia-Inner Mongolia Section) (10 times), with a probability ratio of 25%.

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Table 12.3 Partial statistical results of probability of high-weight indexes Index name

Subsystem

Maximum weight

Top three weights

Number

Probability (%)

Number

Probability (%)

Total scouring and silting volume (lower reaches of the Yellow River)

Sediment situation

12

30

19

31.7

Change rate of estuary wetland area

Ecological factor

6

15

11

27.5

Guarantee rate of ecological base flow of important sections

Environmental factor

6

15

25

62.5

Discharge capacity of the main channel (Ningxia-Inner Mongolia Section)

Hydrological situation

5

12.5

10

25

12.5 Conclusion Taking the Yellow River Basin as an example, this study uses entropy weight and dissipative structure to quantitatively analyze the river life system from a systematic and holistic perspective, and reveals the positive and negative feedback mechanism and the stability (self-recovery ability) evolution law of the Yellow River healthy life system by studying the material circulation and energy flow of the internal elements of the complex system, to optimize and improve the river health assessment system based on RHI, and provide technical support and theoretical basis for the protection and governance of the Yellow River Basin. The study has found that: (1) From 1980 to 2019, the average value of RHI was 64.56 points, with the lowest of 59.12 points in 1994 and the highest of 72.18 points in 2019. The overall evolution law was that it first decreased and then increased, showing an oscillating trend for the better; (2) According to the analysis results from 1980 to 2019, the total scouring and silting volume (the lower reaches of the Yellow River), the change rate of estuary wetland area, the guarantee rate of ecological base flow at important cross sections, and the discharge capacity of the main channel (Ningxia-Inner Mongolia Section) are the key factors affecting the system; (3) In the past five years, the system has reached the state of dissipative structure in 2017, 2018 and 2019 respectively, but the values are relatively low with certain volatility and retracement. It shows that the impact of negative entropy flow

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needs to be continuously strengthened, that is, continuous river basin governance, policy mechanisms, management measures, etc., to provide support for the system to maintain stability, enhance anti-interference ability, or transition to a more stable and advanced state.

12.6 Discussion Maintaining a healthy river life is the ultimate goal of the Yellow River governance. The river is a life community with water as its center. It not only exists independently, but also multiplies, nourishes and promotes the existence of many life entities. It embodies the three basic functions of material circulation, energy flow and information transmission in the process of life movement. The green coordinated development of all functions is essential to the healthy life of the river. This study uses basic sciences such as system theory and information theory to deeply analyze the cyclical evolution law of key elements in the Yellow River life community, construct a positive and negative feedback mechanism based on respecting the value of the river and maintaining the power of river survival, optimize the river health assessment system based on RHI for decision-making and provide support for the protection and governance of the Yellow River Basin. The implementation of the important national strategy of ecological conservation and high-quality development of the Yellow River Basin in the new period has opened up a new realm of river governance and basin economic development in China. Under the background of the country’s new development pattern and new development concept, the value of the river’s healthy life has risen from solving its own basin development problems to being an important support for the country’s construction of a new development pattern. The Yellow River Basin involves nine provinces and regions in the east, middle and west, with different natural resource endowments and diversified levels of economic development. It is a major strategic support for our country to promote the coordinated development of the east, middle and west, and promote the domestic economic cycle and economic growth pole. Therefore, the significance of the research on the river’s healthy life is obvious. The RHI and related theoretical methods proposed in this study will provide important theoretical support and calculation prototype for maintaining the healthy life of the Yellow River and promoting the harmony between people and water in the river basin. Acknowledgements This work was financially supported by The National Key Research and Development Program of China (2022YFC3204305).

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Xiandi P, Xiaohua Z (2016) Reconstruction of a wide channel in the lower reaches of the yellow river under the conditions of new water, sediment and channel adjustments. J Sediment Res 3:53–60 Xianzeng D, Yuliang Y, Yu M, Xinjian G (2021) Comprehensive evaluation on health of main stream of the Huaihe River based on composite fuzzy element-entropy weight combination model. Water Resour Protect 1–10 Xiaoyan L, Yuanfeng Z (2006) Connotation and indexes of healthy Yellow River. J Hydraul Eng 37(6):649–654 Xiaoyan L, Jianzhong Z, Yuanfeng Z (2006) Index system for the healthy life of the Yellow River. J Geogr 05:451–460 Yanwei Z, Zhifeng Y (2005) The concept, evaluation method and direction of river health. Geograph Sci 25(1):119–124 Yiming S, Junxian Z, Shanfeng Z et al (2005) Water pollution in the Yellow River Basin and countermeasures. People’0s Yellow River 27(12):53–54 Yongsheng G, Hao W, Fang W (2007) Construction of river healthy life evaluation index system. Adv Water Sci Yue P, Changxiao L, Jian L (2015) Comprehensive assessment of the ecological security of the Yellow River Basin in Ningxia from 2000 to 2012. Resour Sci 37(12):2480–2490 Zhao C, Pan T, Dou T, Liu J, Liu C, Ge Y, Zhang Y, Yu X, Mitrovic S, Lim R (2019) Making global river ecosystem health assessments objective, quantitative and comparable. Sci Total Environ 667:500–510 Zheren D (2005) Connotation of river health. China Water Resour 04:15–18 Zhongmin Y, Hongbin R (2004) Preliminary Study on water-sediment analysis of the Yellow River and the relationship between scouring and silting and water-sediment in Ningxia-Inner Mongolia section. Northwest Hydropower 3:50–55 Ziyun F (2000) Giving space to rivers and lakes and returning water to clean waters: on the strategic thinking of sustainable development and water control. Water Resour Protect

Chapter 13

Assessment on Recreational Value of the Liming Scenic Spot of Laojun Mountain in Lijiang, China Junmei Li, Pengfei Wang, Guoqi Qian, Runqiu Fei, Yu Fei, Jing Zhou, Jianmei Fu, and Zhidan Deng

Abstract This paper used quantitative method to study the recreational value of tourism resources. The scenic spots have good tourism resources and ecological resources, which need to be protected and managed. Human activities have seriously threatened the ecological resources in the scenic spots. To study the impact of human activities on the environment as well as to estimate the environmental value of scenic spots is very crucial issue for protecting the ecological resources to be sustainable development. The Laojun Mountain Scenic Site in Lijiang, Yunnan Province, P.R. China, is known as the “ancestor of the mountains in Yunnan”, which is one of the most representative landscapes of the “Three Parallel Rivers”.The evaluation of the recreational value of Laojun Mountain Liming Scenic Spot will provide reference for the protection and management of its tourism resources and ecological environment. This study combined travel cost method (TCM) and contingent valuation method (CVM) to evaluate the recreational value of the Liming Scenic Spot of Laojun Mountain in Lijiang in 2015. Using the TCM method, we calculated its recreational value in 2015 to be 103.9 million yuan RMB. Using the CVM method, we estimated its recreational value in 2015 to be 30.1 million yuan RMB. We got the revised its recreation value in 2015 to be 67.0 million yuan RMB using the improved method based on TCM and CVM, which may reflect the recreation value of the J. Li · J. Zhou · J. Fu School of Ecology and Environmental Science and Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, Yunnan University, Kunming 650091, P.R. China G. Qian · R. Fei School of Mathematics and Statistics, The University of Melbourne, Melbourne, VIC 3010, Australia P. Wang · Y. Fei (B) School of Statistics and Mathematics, Yunnan University of Finance and Economics, Kunming 650221, P.R. China e-mail: [email protected] Z. Deng Liming Scenic Area Branch, Lijiang Tourism Investment Co., LTD, Lijiang 974116, P.R. China © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_13

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environmental resources more comprehensively. The study also showed that age and family income of tourists had a significant impact on tourists’ willingness to pay. The Liming Scenic Spot of Laojun Mountain has high recreational value. It should be rationally developed and maintained to make sustainable use of resources. Keywords Travel cost method (TCM) · Contingent valuation method (CVM) · Recreational value · Laojun Mounta

13.1 Introduction This paper used quantitative method to study the recreational value of tourism resources. The scenic spots have good tourism resources and ecological resources, which need to be protected and managed. Human activities have seriously threatened the ecological resources in the scenic spots. To study the impact of human activities on the environment as well as to estimate the environmental value of scenic spots is very crucial issue for protecting the ecological resources. At present, many researches in this field are qualitative. Compared with qualitative research, quantitative research is less. So far, travel cost method (TCM) and contingent valuation method (CVM) are the main methods in literature for evaluating the environmental recreation value, which need to have some questionnaires to support. Although the valuation of ecosystem services has been a challenging issue (Kumar and Kumar 2008), various techniques have been developed to integrate ecological and economic outcomes (Chee 2004; Birol et al. 2006; Barbier 2007; TEEB 2010; Costanza et al. 2011). The methods exist to assess the value of recreational goods and services, including TCM (Willis and Garrod 1991; Garrod and Willis 1999), and CVM (Bergstrom et al. 1990). TCM is often used to evaluate the value of natural attractions or environmental resources that have no market price, which is based on the actual cost (such as travel cost, time cost) and consumer surplus to assess the value of environmental resources. As well as it was the first method to introduce the concept of consumer surplus into a public goods assessment, which was first proposed by U.S. economist Harold Hotelling in 1947. In the 1970s and 1980s, TCM was widely used in the economic valuation of tourism resources, such as forest parks (Willis and Garrod 1991). This method has become one of the most used methods of assessing recreational value. Some scholars used the regional TCM to evaluate the recreational value of Changbai Mountain Reserve, Dinghushan Scenic Site, and Wuyishan National Scenic Site (Xue et al. 1999; Wu and Luo 2002; Ai et al. 1996). Zhang and Cai (2007) applied the multidestination TCM model based on sites to estimate the total recreational value of Jiuzhaigou Nature Reserve in 2002. Xie and Ma (2006) used the TCM method to calculate the total recreational value of the Huangshan Scenic Site in 2004 to be 3.532 to 4.395 billion yuan. Zhao et al. (2008) elaborated on the basic idea of the TCM and used a tourism demand curve established with increased travel costs and total tourist visits and a demand curve established with the travel cost of each district

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and tourist visits to assess the recreational value of the Xinglongshan Nature Reserve in Gansu Province. From the comparison of actual cases, it was evident that both technical routes were feasible. Xie et al. (2008) conducted a comparative analysis of the travel cost interval analysis (TCIA) and the zonal travel cost method (ZTCM) from the perspective of points and used TCIA to evaluate the recreational value of the Wuhan East Lake Scenic Site. CVM is also known as the willingness survey method. The CVM is widely adopted in evaluating environmental assets, and provides a suitable monetary valuation of non-priced services (Garrod and Willis 1999). CVM which is based on respondent’s responses in the questionnairs can evaluate the economic value of intangible and tangible benefits of various environmental resources and has been widely used in the assessment of recreational value, choice value, and existence value of environmental resources. The method involves asking people how much they would be willing to pay, or how much compensation they would require, to gain access to or preserve a particular environmental good or service. Dong et al. (2011) used the CVM to evaluate the recreational value of Jiuzhaigou World Natural Heritage Site, and in combination with other relevant domestic literature, they analyzed the deviation of CVM in a tourism resource value assessment. They found that the value resulting from the CVM evaluation method was low. Liu and Meng (2013) used the CVM to analyze the correlation between the basic information of tourists and the willingness to pay (WTP) when assessing the total recreational value of Shaanxi Evergreen Nature Reserve. Chen et al. (2014) enriched the CVM case study by taking Belgium as an example. Hamed et al. (2016) attempted to assess the impact of SLR on economic loss of sea turtle habitat along the Florida coast. Xiao et al. (2015) evaluated the value of natural landscapes in China which also enriched the CVM case study. To evaluate the value of environmental resources with TCM and CVM. Both TCM and CVM have their advantages and disadvantages. TCM can be difficult to obtain accurate data on travel costs and visitor numbers. CVM relies on people’s stated preferences, which may not always reflect their actual behavior. TCM is based on the actual cost and consumer surplus, Using TCM, we calculated the consumer surplus based on the highest price of tickets that can be accepted by tourists and the corresponding number of people who paid each price, then we evaluated the recreational value. And CVM is based on respondent’s responses on WTP (willing to pay) for preference of the environmental resources. The aforementioned discussions entail that we should try to conbine with the both methods together and apply a particular case to get a more appropriate research result. This paper uses TCM and CVM together to study and evaluate the recreational value of the Laojun Mountain Liming Scenic Site in Yulong County, Lijiang, China, in a way that the advantages of TCM and CVM will be boosted yet their drawbacks will be mitigated. In further, we can get the revised environmental recreation values with the improved method which will be stated in the part of methods. This in general would provide valuable information for decision-makers and policymakers on pricing and valuing environmental resources. This paper is organized as following: We first introduce overview of the region in Sect. 13.2. In Sect. 13.3, we develop the proposed method. Then we apply the

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proposed method to evaluate the recreational value of the Laojun Mountain Liming Scenic Site in Yulong County, Lijiang, China as a case in Sect. 13.4. Section 13.5 discusses the result using TCM and CVM. Finally, in Sect. 13.6 we get the conclusion.

13.2 Overview of the region The Liming Scenic Spot of Laojun Mountain has high recreational value. It should be rationally developed and maintained to make sustainable use of resources. The Laojun Mountain Scenic Site in Lijiang, Yunnan Province, is known as the “ancestor of the mountains in Yunnan.” Laojun Mountain is located between 26°38' –27°15' north latitude and 99°7' –100°00' east longitude, with an altitude of 2100–4515 m. This magnificent place is one of the most representative landscapes of the “Three Parallel Rivers.” This site boasts three world crowns of natural heritage, national key scenic spots, and national geological parks. With the increasing popularity of Laojun Mountain, more tourists are visiting this site, and frequent human activities have seriously threatened the ecological resources of Laojun Mountain. To attract more tourists, it is particularly important for the government to protect Laojun Mountain’s ecological resources, which requires an accurate understanding of its economic value. This study evaluated the recreational value of the Laojun Mountain Liming Scenic Site to provide a scientific basis for the government to strengthen the management of the ecological environment.

13.3 Methods 13.3.1 Travel Cost Method (TCM) TCM is often used to evaluate the value of natural attractions or environmental resources that have no market price, which is based on the actual cost (such as travel cost, time cost) and consumer surplus to assess the value of environmental resources. It was the first method to introduce the important concept of consumer surplus into a public goods assessment. TCM needs to have some questionnaires to support. In this method, the recreational value of the scenic spot is the total willingness to pay of the scenic spot, which is obtained by the sum of the three parts of the travel cost of the tourists, the time cost, and the consumer surplus. One of the advantages of this approach is the introduction of consumer surplus, which allows for a more accurate assessment of the value of tourism resources. Travel cost refers to the actual expenditures incurred by tourists from touring a scenic site. Time cost refers to the opportunity cost of the time spent by tourists visiting a scenic site (a portion of time used by tourists that can provide a certain income if used for work). Consumer

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Fig. 13.1 Consumer surplus

surplus refers to the difference between the maximum willingness of the tourists to pay and the actual payment. Following is a brief introduction to consumer surplus: In Fig. 13.1, line AB represents the demand curve of the tourist site (the actual line will not be a straight line; for the convenience of explaining the principle, a straight line is used instead), point M is the actual travel cost and traveler combination point, P is the corresponding cost, and Q is the number of tourists at this time. The consumer surplus at this time is the area enclosed by the three points of PAM.

13.3.2 Contingent Valuation Method (CVM) CVM is designed to construct a hypothetical market for virtual payment through a simulated scenario and to obtain the consumer’s WTP. The assumption of CVM is that respondents are rational and self-interested economic people. Respondents are required to position themselves as consumers before making their choices. They determine their own “payments” to improve their welfare. This method directly asks people about their WTP to visit the scenic site and uses it as the basis for evaluating the economic value. It also uses WTP to estimate the recreational value of the scenic site—that is, the per capita WTP for the sample multiplied by the total number of tourists who visit the scenic site. CVM also needs to have some questionnaires to support.

13.3.3 Questionnaire Design and Sample Survey 13.3.3.1

Questionnaire Design

In the evaluation of recreational value, the TCM method calculates the time cost of the consumer, the actual travel cost, and the consumer surplus. The CVM needs to calculate the consumer’s average WTP. The key to designing the questionnaire was to obtain the data and information needed to calculate recreational value. This primarily

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included travel time, travel cost, multiple-destination trips, tourists’ WTP, and the number of visits by tourists to the scenic site, as well as demographic information of the tourists (e.g., gender, age, occupation, and income).

13.3.3.2

Sample Survey

After the preliminary design of the questionnaire, we revised the questionnaire after two pre-surveys to determine the final form of the questionnaire. We conduct questionnaire survey in the way of random sampleing. During the period from July 30 to August 23, 2015, several investigators conducted three questionnaire surveys in the way of random sampleing at the Laojun Mountain Liming Scenic Site. They distributed 180 questionnaires at the site and collected 168 valid questionnaires (93.33%).

13.3.4 Data Organization and Pre-Processing With TCM, the recreational value of the scenic spot is the total willingness to pay of the scenic spot, which is obtained by the sum of the three parts of the travel cost of the tourists, the time cost, and the consumer surplus. With CVM, we will use the WTP which can response people’s preference for environmental resources to estimate the recreational value of the scenic site—that is, the per capita WTP for the sample multiplied by the total number of tourists who visit the scenic site. We also need to estimate the number of tourists in scenic sites.

13.3.4.1

TCM Implementing

Time Cost Calculation To calculate the time cost, it was first necessary to determine the time spent by tourists visiting the scenic site. This time mainly included the round-trip time from the departure point to Lijiang (h1 ). Because tourists come to Lijiang to visit sites, h1 was shared. According to data published online by the Lijiang City Tourism Bureau, the average time for tourists to stay in Lijiang was three days. It took one day for tourists to visit Laojun Mountain, Yulong Snow Mountain, and Lashi Sea. On the basis of this average time, we set the multiple-destination trips sharing proportion as one-third. The round-trip time of Lijiang to the scenic site is h2 , the time spent in the scenic site is h3 , and the total time is H = 13 × h 1 + h 2 + h 3 . Next, we considered the conversion of time cost. To convert the total time H a ratio of the wage rate of one-third to one-half has been used in the literature (Xue et al. 1999; Ai et al. 1996; Xie and Ma 2006; Zhao et al. 2008) and it is better to use one-third (Xie and Ma

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2006; Xie et al. 2008). This paper used one-third as the assignment coefficient for the time cost. The conversion formula of average travel time cost of tourists is as follows: CH =

S 1 × ×H 3 D

(13.1)

where C H is the time opportunity cost, S is the employee’s monthly average salary of 4290 yuan (2014 statistical yearbook), D is 176 h of standard working hours in one month stipulated by the China, and H is the total time.

Travel Cost Calculation (1) Multiple-Destination Trip Problem The multiple-destination trip problem is an important issue in evaluating recreational value. Through the literature, we found three methods for handling the multipledestination trip problem (Parsons 2003; Loomis and Walsh 1997): (1) Multiple destinations. We excluded multiple-destination samples to retain only a single destination sample, which was suitable for the case in which tourists were basically single-destination tourists. (2) Cost-sharing method. The method divides the travel cost into varying proportions among the various sites. For instance, some researchers have used the number of nights spent at different sites to measure the relative importance of the sites (Knapman and Stanley 1991), and other researchers have surveyed tourists’ preferences and distributed travel cost based on their preferences for different attractions. (3) Combination method. The combination of sites method was proposed by Mendelsohn et al. (1992).The base model is modified to include multiple destinations. This method expanded the concept of sites and treated a group of sites in the round-trip tour as one site, calling this group of sites a combination. This study handled the multiple-destination trip problem based on the cost-sharing method. (2) Calculation of Travel Cost For free travelers, the travel cost is calculated as follows: C1 =

c11 + c12 + c13 + c14 + c15 + c16 3

(13.2)

where C 1 denotes the total travel cost of each visitor, c11 indicates the round-trip fare from the departure point to Lijiang, and c12 indicates the ancient city maintenance fee for tourists. The ancient city of Lijiang is a transit point for tourists, and tourists visit multiple sites in Lijiang. The two expenses c11 , c12 need to be allocated, using

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the sharing proportion of one-third, c13 , c14 , c15 , c16 represents the round-trip costs of traveling from Lijiang to the scenic site, the expenses of tourists in the scenic site (including tickets and other expenses in the scenic site), tourist’ accommodation expenses in Lijiang, and tourists’ dining expenses in Lijiang, respectively. According to the formula, by default, tourists selected Lijiang as the transit point, which was also the tourist’s main travel route to Lijiang. For tourists who traveled in a group from the starting point, and considering that tourists not only visited Lijiang, but also visited such tourist sites as Kunming and Dali, the travel cost of each site was evenly shared using the ratio of the total number of days in Lijiang over the total number of days for the entire trip. We then divided the travel cost of each site according to the local multiple-destination trip handling method in Lijiang. The calculation of travel cost is as follows: C2 =

1 d1 × c21 × + c22 d 3

(13.3)

where C 2 indicates the travel cost of the tourists who are on a tour group and d 1 , d, c21 , c22 denotes the number of days the tourists stay in Lijiang, the total number of days of the entire trip, the cost of joining the tourist group, and the expenditure of the tourists in the scenic site, respectively. For tourists who join a tourist group in Lijiang, the calculation formula for travel cost is: C3 =

c32 c31 + + c33 + c34 3 n

(13.4)

where C 3 indicates the travel cost of the tourists who join a tourist group in the Lijiang, and c31 indicates the round-trip fare from the departure point to Lijiang. The fee is still allocated according to the sharing proportion of one-third for multipledestination trips to the Lijiang scenic site; c32 indicates the cost of joining a tourist group, n indicates the number of scenic sites included in the tour group fare, c33 indicates the expenditures of the tourists in the scenic site, and c34 indicates the lodging expenses of the tourists in Lijiang.

Consumer Surplus Calculation We obtained tourists’ WTP and the corresponding tourist count according to the questionnaire survey. When the total number of tourists was 10,000, we calculated the number of tourists corresponding to each ticket price according to the proportion of the corresponding number of tourists in the different ticket prices. We then estimated the demand curve based on the relationship between the cost of the ticket and the number of visitors, thereby estimating the per capita consumer surplus. The regression function model of the demand curve: yi = β0 + β1 xi + β2 xi2 + β3 xi3 + εi

(13.5)

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where yi denotes the number of tourists, and xi denotes the ticket cost, εi is the error term. According to this function, the consumer surplus is calculated as follows: Δ

∫

CS =

Δ

Δ

Δ

βˆ0 + β1 x + β2 x 2 + β3 x 3 d x

(13.6)

Ωx

13.3.4.2

CVM Implementation

With CVM, we will use the WTP to estimate the recreational value of the scenic site—that is, the per capita WTP for the sample multiplied by the total number of tourists who visit the scenic site. The key is to calculate per capita WTP. In the statistical analysis of CVM data, there is substantial controversy in the academic community about whether the expected value of WTP should be represented as an average or median. The theoretical basis of WTP comes from the principle of income compensation under the established conditions of Hicks consumer surplus welfare, and the calculation of equal variation or compensation variation is based on the average. Some researchers believe, however, that because the respondent’s WTP value is relatively discrete in many cases, the average value is easily distorted by the extreme values and may cover the difference between the preferences of the respondents. Therefore, these researchers have argued that the median value should be used instead of the average (Loomis and Bateman 1993). Most of the domestic CVM research uses the median value. In fact, use of the average or the median value depends on the purpose of the study. Bateman et al. believe that if science-based decision-making is emphasized, the average should be used. From the perspective of social justice, the median value indicates what 50% of the respondents are willing to pay so the median value is applicable to democratic decision making (Bateman et al. 2002). CVM research in developed countries is used mainly to serve local residents and communities, provide a basis for public management and democratic decision-making, or provide expert testimony to the courts, thus using median values more often (Bateman et al. 2002). Under the current stage of economic development and political system in China, the possible applications of CVM research include cost analysis of resource environment, transfer of use rights, and comparison among the multiple purposes of resources, which provide a basis for scientific decision-making of resource owners. Therefore, the average value should be used. In this study, we used the average value to calculate the per capita WTP.

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Estimation of Number of Tourists in Scenic Sites

About estimation of number of tourists in scenic sites, according to the National Tourism Administration, the number of tourists during the “Twelfth Five-Year Plan” period (2011–2015) increased by 9%, during which time the Laojun Mountain Scenic Site was still in its infancy. The increase in the number of tourists should exceed this level. We calculated the number of tourists visiting Laojun Mountain in 2015 at an annual increasing rate of 10%. According to a sampling survey of the number of tourists visiting attractions in Yulong County in 2014, the number of tourists in Laojun Mountain Liming Scenic Spot in 2014 was 58,555, and the number of tourists visiting the Laojun Mountain Liming Scenic Site in 2015 was 64,411.

13.3.4.4

To Evaluate the Value of Environmental Resources Combining with TCM and CVM Together

How to combine with TCM and CVM together and apply a particular case to get a more appropriate research result. TCM can be difficult to obtain accurate data on travel costs and visitor numbers. CVM relies on people’s stated preferences, which may not always reflect their actual behavior. TCM is based on the actual cost and consumer surplus, Using TCM, we calculated the consumer surplus based on the highest price of tickets that can be accepted by tourists and the corresponding number of people who paid each price, then we evaluated the recreational value. And CVM is based on respondent’s responses on WTP (willingness to pay) for preference of the environmental resources. We can get the revised environmental recreation values using the improved method based on TCM and CVM, in a way that the advantages of TCM and CVM will be boosted yet their drawbacks will be mitigated. And we will consider calculating the weighted sum of the two evaluated results, which may reflect the recreation value of the environmental resources more comprehensively. In this paper, we will calculate the weighted sum of the two evaluated results with the equal weight.

13.4 Results 13.4.1 Result of Estimation of Recreational Value of Scenic Sites Using TCM The per capita time opportunity cost is 161.53 yuan, which is calculated by formula (13.1) in the part of method, and the per capita travel cost is 1424.80 yuan. By summarizing and calculating responses from the questionnaires, we obtained the number of tourists relative to the different ticket prices in the Lashi Sea Scenic Site (Table 13.1).

13 Assessment on Recreational Value of the Liming Scenic Spot of Laojun … Table 13.1 Ticket prices and the corresponding number of visitors to Laojun Mountain

Ticket price (yuan)

Number of tourists

105

10,000

120

3750

150

1964

200

595

250

357

165

The regression function model of the demand curve was calculated by the statistical software R version 3.1.2: yˆ = 103600 − 1621x + 80365x 2 − 0.0141x 3 (R 2 = 0.94) where yˆ denotes the number of tourists, and x denotes the ticket cost. According to this function, the consumer surplus is calculated as follows: ∫250 C S = 103600 − 1621x + 80365x 2 − 0.01414x 3 d x = 262464.3 105

Therefore, the per capita consumer surplus = 26.25 yuan. Per capita WTP = 26.25 + 161.53 + 1424.80 = 1612.58 yuan. The total recreational value of Laojun Mountain = 1612.58 × 64,411 = 103,867,890.38 yuan.

13.4.2 Result of Estimation of Recreational Value of Scenic Sites Using the CVM 13.4.2.1

Recreational Value of Scenic Sites

We used the CVM method to collect and collate questionnaires and calculate the recreational value of Liming Scenic Spot of Laojun Mountain, that is, the per capita WTP was 468.09 yuan/person, and the total recreational value was 30,149,910 yuan per year.

13.4.2.2

Analysis of the Basic Characteristics of Tourists

To analyze which of the five factors (i.e., gender, age, family income, education level of tourists, and urban residency) had the most significant impact on tourists’ WTP, this study used the Pearson χ2 test method. Because of the scattered distribution of

166 Table 13.2 Test results of Pearson χ2 for Laojun Mountain

J. Li et al. χ2

df

p

1.819

2

0.403

Age

22.843

8

0.004**

Factor Gender Family Income

18.978

8

0.015*

Education level

2.133

6

0.907

Urban residency

0.208

2

0.901

Notes * p < 0.05, ** p < 0.01

tourist’s WTP, we divided tourists’ WTP into three levels based on the WTP table. The first level was below 0–299 yuan, the second level was 300–800 yuan, and the third level was greater than 800 yuan. We calculated and summarized the Pearson χ2 test results of the Laojun Mountain payment factor using the statistical software R version 3.1.2 (Gao et al. 2013) (Table 13.2). Table 13.2 clearly shows that age and family income of tourists had a significant impact on WTP. Next, we explored the specific influence of these factors on tourists’ WTP (Fig. 13.2). As shown in Fig. 13.2, the tourists who traveled to Laojun Mountain were concentrated in the 18–30 and 31–40 age-groups. As family income increased, the average tourists’ WTP increased.

Fig. 13.2 Willingness to pay

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13.4.3 The Revised Recreational Value of Scenic Sites Using the Improved Method Based on TCM and CVM In this paper, we calculate the weighted sum of the two evaluated results with the equal weight. We got the revised its recreation value in 2015 to be 67.0 million yuan RMB using the improved method based on TCM and CVM, which may reflect the recreation value of the environmental resources more comprehensively. The revised recreational value of Laojun Mountai = 103,867,890.38 × 0.5 + 30,149,910 × 0.5 = 67,008,900.19 yuan.

13.5 Discussion We determined the accuracy of the CVM assessment results by both the WTP and the population range extension, and the final evaluation result was far less than that of TCM. This also confirmed the shortcomings of the CVM in underestimating the value of tourism resources (Cai and Zhang 2008). We can get the revised environmental recreation values using the improved method based on TCM and CVM, in a way that the advantages of TCM and CVM will be boosted yet their drawbacks will be mitigated. And we considered calculating the weighted sum of the two evaluated results, which may reflect the recreation value of the environmental resources more comprehensively. The purpose of using the CVM and the TCM to assess the recreational value of tourist sites was to explore the importance and value of ecological resources and to monetize their comprehensive benefits, which helps to avoid resource idleness, improve tourism management, guide tourism investment, lay the foundation for promoting tourism resource asset management and market operation, and provide a reference for government departments and operating enterprises to ensure environmental protection and environmental fees. To promote the sustainable development of environment and resource.

13.6 Conclusions This study estimated the recreational value of tourism resources in the Laojun Mountain Liming Scenic Site in Lijiang, China. Through the use of CVM and TCM, we quantitatively evaluated the recreational value of the tourist site. The recreational value was high and there was great potential for development. Using the TCM method, we estimated the recreational value of the Laojun Mountain Lining Scenic Site in 2015 to be 103.9 million yuan. Using the CVM method, we estimated its recreational value in 2015 to be 30.1 million yuan. We got the revised its recreation value in 2015 to be 67.0 million yuan RMB using the improved method based on TCM

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and CVM, which may reflect the recreation value of the environmental resources more comprehensively. In the CVM method evaluation, we explored which factors had the most significant impact on tourist’s WTP. The results showed that age and family income of tourists had a significant impact on their WTP. Tourists were mainly concentrated in the 18–30 and 31–40 age groups. At the same time, as family income increased, WTP increased and stabilized. The Liming Scenic Spot of Laojun Mountain has high recreational value. It should be rationally developed and maintained to make sustainable use of resources. Declarations Funding: This study was funded by Yunnan Philosophy and Social Science Research Base Projects (JD2019YB05 and JD2016YB03); The program of Yunnan Provincial government-sponsored study abroad in 2019(File No. 2019003). Conflict of Interest: The authors declare that they have no conflict of interest. Author Contributions: The eight co-authors together contributed to the completion of this article. Junmei Li was the first author on writing-original draft preparation, writing-review, and submission process; Pengfei Wang, Runqiu Fei, Jing Zhou, and Jianmei Fu contributed to data analysis, the results, and conclusion; Guoqi Qian contributed to writing-review, editing. Zhidan Deng contributed to investigation; Yu Fei acted as corresponding author on their behalf throughout writing-review, editing. All authors have read and agreed to the published version of the manuscript.

References Ai YY, Gao L, Qiu JQ (1996) Study on the recreational benefits of Wuyishan national scenic spot. J Beijing Forestry Univer 18(3):89–97 Barbier E (2007) Valuing ecosystem services as productive inputs. Economic Policy 22(49):177–229 Bateman IJ, Carson RT, Day B (2002) Economic valuation with stated preference techniques: a manual. Edward Elgar Publishing Ltd., Cheltenham Bergstrom JC, Stoll JR, Titre JP et al (1990) Economic value of wetlands-based recreation. Ecol Econ 2(2):129–147. https://doi.org/10.1016/0921-8009(90)90004-E Birol E, Karousakis K, Koundouri P (2006) Using economic valuation techniques to inform water resources management: a survey and critical appraisal of available techniques and an application. Sci Total Environ 365(1):105–122. https://doi.org/10.1016/j.scitotenv.2006.02.032 Cai YY, Zhang AL (2008) Estimate the leisure landscape and existence value of recreational Value Wuhan pomegranate red farm. Acta Ecol Sinica 28(3):1201–1209 Chee YE (2004) An ecological perspective on the valuation of ecosystem services. Biol Cons 120(4):549–565 Chen WY, Aertsens J, Liekens I, Broekx S, Nocker LD (2014) Impact of perceived importance of ecosystem services and stated financial constraints on willingness to pay for Riparian Meadow restoration in flanders (Belgium). Environ Manage 54(2):346–359. https://doi.org/10.1007/s00 267-014-0293-z Costanza R, Kubiszewski I, Ervin D, Bluffstone R, Boyd J, Brown D, Chang H, Dujon V, Granek E, Polasky S, Shandas V, Yeakley A (2011) Valuing ecological systems and services. F1000 Biol Report 3:14. https://doi.org/10.3410/B3-14

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Dong XW, Zhang J et al (2011) Bias analysis and reliability and validity test in contingent valuation method: a case study of assessment of Jiuzhaigou’s recreational value. Acta Geograph Sinica 66(2):267–278 Gao T, Xiao N, Chen G (2013) R in action: data analysis and graphics with R. Posts and Telecom Press, Beijing, pp 229–230 Garrod G, Willis KG (1999) Economic valuation of the environment: methods and case studies. Edward Elgar Publishing Ltd., Cheltenham Hamed A, Madani K, Von HB, Wright J, Milon JW, Bossick M (2016) How much are floridians willing to pay for protecting Sea turtles from sea level rise? Environ Manage 57(1):176–188. https://doi.org/10.1007/s00267-015-0590-1 Knapman B, Stanley O (1991) A travel cost analysis of the recreation use value of kakadu nation park. Canberra, Resource Assessment Commission Inquiry Kumar M, Kumar P (2008) Valuation of the ecosystem services: a psycho-cultural perspective. Ecol Econ 64(4):808–819. https://doi.org/10.1016/j.ecolecon.2007.05.008 Liu J, Meng QS (2013) Recreation value evaluation based on CVM for Changqing national nature reserve. Forest Resour Manage 3(20):63–68. https://doi.org/10.13466/j.cnki.lyzygl.2013.03.020 Loomis J, Bateman I (1993) Some empirical evidences on embedding effect in contingent valuation of forest protection. J Environ Econ Manag 24(1):45–55 Loomis JB, Walsh RG (1997) Recreation economic decisions: comparing benefits and costs. Venture Publishing, State College, PA Mendelsohn R, Hof J, Peterson G, Johnson R (1992) Measuring recreation values with multiple destination trips. Am J Agr Econ 74:926–933 Parsons GR (2003) The travel cost method. In: Champ P et al. (d) A Primer on non-market valuation. Holland, Kluwer Academic Publisher The Economics of Ecosystems and Biodiversity (TEEB) (2010) The economics of ecosystems and biodiversity: ecological and economic foundation. London, Earthscan Willis KG, Garrod G (1991) An individual travel-cost method of evaluating forest recreation. J Agric Econ 42(1):33–42. https://doi.org/10.1111/j.1477-9552.1991.tb00330.x Wu ZW, Luo YJ (2002) Dinghushan scenic value evaluation of forest recreation. Forestry Econ 9(20):40–42. https://doi.org/10.13843/j.cnki.lyjj.2002.09.020 Xiao Y, Cheng C, Yang W, Ouyang ZY, Rao EM (2015) Evaluating value of natural landscapes in China. Chin Geogra Sci 26(2):244–255. https://doi.org/10.1007/s11769-015-0795-5 Xie XZ, Ma Z (2005) Review of studies of valuing nature with travel cost method. J Hefei Univer Technol (natural Sci) 28(7):730–737 Xie SY, Zi RZ, Xu YJ, Hu J (2008) A comparison between travel cost interval analysis method and zonal travel cost method and its application. Tourism Tribune 23(2):41–45 Xie XZ, Ma Z (2006) Evaluation recreation value of Mount. Huang using travel cost method. Resour Sci 28(3):129–136 Xue DY, Bao HS, Li WH (1999) A study on tourism value of biodiversity in Changbaishan Mountain biosphere china. J Natural Resour 14(2):140–145 Zhang Y, Cai YL (2007) Using a multiple-destination-based zonal travel cost method to evaluate the recreational benefits of Jiuzhaigou nature reserve. J Nat Resour 19(5):651–661 Zhao Q, Li XM, Gu CQ (2008) A study of travel cost method. J Univer Jinan 2(2):213–219. https:// doi.org/10.13349/j.cnki.jdxbn.2008.02.025

Chapter 14

The Study on Sustainable Protection and Development of Huizhou Ancient Road Cultural Ecology Resources from Ecological Perspective Bi Zhongsong, Zhang Xiao, Li Yunzhang, Cheng Peng, and Zhang Huizhen

Abstract As an important component of linear heritage, Huizhou Ancient Road has outstanding universal value and typical ecological and cultural characteristics. In a broad sense, Huizhou ancient roads refer to all the flagstone mountain roads and affiliated ancient pavilions, ancient bridges, ancient temples and other architectural heritage within the ancient Huizhou Prefecture and from Huizhou Prefecture to the periphery, including rich cultural landscape and natural landscape. This article takes the Ruolin Ancient Road and Jingshe Ancient Road as examples to analyze the main heritage composition, prominent universal value, and typical ecological cultural characteristics of the Ruolin Ancient Road and Jingshe Ancient Road from an ecological perspective. It also comprehensively investigates the heritage resources of the ancient road, constructs the Huizhou Ancient Road Culture and Ecological Protection Corridor, and constructs a complete Huizhou Ancient Road overall protection system Exploring the basic strategies for sustainable protection and utilization of Huizhou ancient roads in promoting rational utilization and other aspects, with the aim of making beneficial explorations for the protection of the linear heritage of Huizhou ancient roads. Keywords Ecology · Linear heritage · Huizhou ancient road · Ecological corridor · Sustainable protection

B. Zhongsong · Z. Xiao · C. Peng School of Architecture and Civil Engineering, Huangshan University, Huangshan 245041, China B. Zhongsong · L. Yunzhang · Z. Huizhen (B) College of Architecture and Environment, Sichuan University, Chengdu 610065, China e-mail: [email protected] B. Zhongsong · Z. Xiao · C. Peng Anhui Provincial Institute for Preservation and Inheritance of Huizhou-Style Architecture, Huangshan 245041, China © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_14

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14.1 Introduction In ancient times, Huizhou started from the two counties of she and she set up in Qin Dynasty. In 1121, the third year of Xuanhe reign of Huizong in Song Dynasty, she was changed into Huizhou. Since then, the geographical category of “one Prefecture and six counties” has been formed, that is, she County, she County, Xiuning County, Jixi County, Wuyuan County, Qimen County under the jurisdiction of Huizhou Prefecture, which is Hui town of she county. From the fifth year of the Tang Dynasty to the end of the Qing Dynasty, the scope of ancient Huizhou basically did not change greatly (Jinlong and Han 2018). The number and types of historical remains in ancient Huizhou are very rich, including ancient dwellings (Zhongsong 2014), ancient ancestral halls (Zhongsong et al. 2014), ancient theatres (Zhongsong and Lili 2014), ancient roads and other heritage types. According to incomplete statistics, there are about 124 large and small ancient roads and nearly 1000 ancient bridges in the ancient “one Prefecture and six counties” (Yang and Qi 2016). However, with the development of economy and the continuous reconstruction of modern transportation system, the traditional road system has been impacted unprecedentedly. At the same time, due to the influence of disrepair and geological disasters, the ancient Huizhou road has been greatly damaged. In this context, Taking Huining ancient road as an example, this paper analyzes its cultural relics composition, value characteristics and protection strategies from the perspective of heritage corridor, in order to make a beneficial exploration for the protection of Huizhou Ancient Road Cultural line heritage.

14.2 Ecological Environment of Huizhou Ancient Road Distribution Area Huizhou is not only a geographical concept in history, but also a cultural unit today. It represents the extensive and profound regional culture of Huizhou. The unique living environment of “seven mountains, one water, one field, one road and manor”, and the helpless life experience of “living in Huizhou, thirteen or four years old, and throwing out” have enabled the hardworking ancestors of ancient Huizhou to open up a series of ways for Huizhou merchants to communicate with the outside world between the mountains and mountains—the ancient Huizhou Road, which also created the ancient Huizhou road that did not take farming, but took commerce as the development axis The legend of Huizhou merchants that has galloped for three hundred years in ancient China has created a unique landscape of “no town without Huizhou”, leaving a large number of mountain cultural relics represented by ancient roads (Fig. 14.1). From the existing distribution, there are three types of spatial relationship between Huizhou ancient roads and the geographical and ecological environment: first, they

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Fig. 14.1 Ecological environment of Huizhou ancient road area (the ecological environment and village environment of the Ruoling ancient road in Shexian county)

are distributed in hills and plains. This part of the ancient road connects the larger towns, market towns and important settlements in Huizhou. The road alignment is relatively straight, and it is an important traffic trunk line. The agricultural ecological environment is mainly along the road. Second, ancient roads are distributed along rivers. Huizhou has a large river network density. There is an important river in the territory—Xin’an River directly connects Qiantang River in Zhejiang Province to the East China Sea. In addition, there is the Yangtze River basin. A large number of Huizhou ancient roads are distributed along the river, which is easy to build. The ecological environment along the road is good, but the route is long, connecting important villages along the way. Third, Huizhou Ancient Road crosses mountains and mountains. As there are many mountains in the south of Anhui, most of the ancient roads cross the mountains and are distributed in the vast mountain areas, and the route selection is reasonable in combination with the mountain terrain. Located in Shitai County, Anhui Province, the ancient Huidao of Juegen Pass has basically chosen a straight and short terrain, with sufficient sunshine and good geological conditions. It rarely encounters landslides and mud rock flows. The selection of the ancient Huidao here is related to local human settlements, properties, location and other factors, reflecting the rationality and scientificity of the site selection. The ancient buildings, the ancient Great Wall, the ancient tombs Ancient sites such as ancient pavilions and temples are distributed in the mountains centered on Xianyu Mountain and Ancient Huidao Road. The layout is reasonable, and the architectural location is selected flexibly and skillfully in combination with the geographical mountain shape and water veins, which is natural and harmonious (Fig. 14.2).

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Fig. 14.2 Analysis of the elevation, slope, aspect and shadow of the mountain where the ancient Huidao of Jugenguan Pass is located

14.3 Composition of Heritage of Ruoling Ancient Road and Jingshe Ancient Road 14.3.1 Route Distribution of Ruoling Ancient Road and Jingshe Ancient Road Ruoling ancient road and Jingshe ancient road are located at the intersection of Shexian County, Huangshan District, Xuancheng City, Jixi County and Jingde County, Huangshan City, Anhui Province. The two ancient roads meet at ruolingtou, Shexian county (Fig. 14.3). Ruoling ancient road goes from Shexian County, ancient Huizhou prefecture to Taiping County (now Huangshan District, Huangshan City) and finally reaches gu’anqing prefecture (now Anqing City), Jingshe ancient road goes from she county to Jingde County through Ruoling, and finally to the government of Ning (now Ningguo City). Ruoling ancient road and Jingshe ancient road are about 28.6 km long and 0.7–2 m wide, both of which are stone roads. In ancient times, they were the main official roads connecting Anqing and Ningguo in Huizhou. According to the current administrative region, Ruoling ancient road is divided into Ruoling ancient road Shexian section and Ruoling ancient road Huangshan section. Shexian Section of Ruoling Ancient Road Shexian section of Ruoling ancient road starts from Maoshe village, Xucun Town, Shexian county. It passes Shuikou bridge, Yong’an bridge, Xia Erliban pavilion, Tudi temple and Shijingzhuang to Chatan Village. It passes Chatan bridge, Shang Erliban pavilion, Shili Bridge and Zhonglie temple to Ruolingguan cave. It is about 5 km long and 1.6–2 m wide. Huangshan Section of Ruoling Ancient Road The Huangshan section of Ruoling ancient road runs northward from Ruoling Pass, through Ledezuo nunnery site, Bali

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Fig. 14.3 Route distribution of Ruoling ancient road and Jingshe ancient road

hillock site and Qilong nunnery site, and then to Tanjia Bridge, Xia Jiaoling natural village, East Huangshan Village, Tanjia Bridge Town, Huangshan District, with a total length of 8.6 km and a width of 1.6–2 m. Jingshe Ancient Road Jingshe ancient road runs from the northeast of Ruoling pass to seling, Jingde County, Xuancheng City. It passes through Tianxing cave, Wangzi cave, Tianzhu nunnery site, Kaobi cave, Tathagata pillar and Wuli cave to 2.5 km southwest of Gaojia Village, with a total length of 15 km and a width of 0.7–1.5 m.

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Fig. 14.4 The Jingshe ancient road and its surrounding mountain vegetation environment

14.3.2 Heritage Composition of Ruoling Ancient Road and Jingshe Ancient Road Ancient Road Only two levels of headings should be numbered. Lower level headings remain unnumbered; they are formatted as run-in headings. Ruoling ancient road and Jingshe ancient road are distributed in the mountainous area of Southern Anhui Province, and they were first excavated in the late Sui Dynasty. They are also called Millennium ancient official road and Sui Tang ancient road. The ancient road is basically straight and short terrain, with sufficient sunshine and good geological conditions. The paving materials of the ancient road are basically local materials. The local granite, shale and other stones are selected as the main pavement materials, which have high hardness and are not easy to be weathered. Ruoling ancient road and Jingshe ancient road were regarded as military strongholds in the past dynasties. There were military passes. There was a patrol department in the Ming and Qing Dynasties. Today there are military buildings such as Ruoling pass and Tianxing Cave (Fig. 14.4). Ancient Village Ruoling ancient road starts from Maoshe Village, Xucun Town, Shexian County, and goes to Ruoling. Maoshe Village, Chatan Village and Ruoling ancient road are closely related. Maoshe Village is located at the foot of Ruoling mountain. In the early Ming Dynasty, Fang’s surname came from Lingshan mountain to Maoshe Villag, which became a village. Before the 1950s, the thatched cottage sold rice from Taiping and Jingde through Ruoling ancient road and Jingshe ancient road. After the rice was transported, it was put at the door every morning. At this time, the rice traders around Xucun rushed here to trade. The thatched cottage became an important rice trading market on the ancient road. Chatan Village is located between the foot of Ruoling mountain and the Guandong cave of Ruoling mountain. Its main surname is ye. It moved to live in the late Ming Dynasty and the early Qing Dynasty, and also sold rice through the ancient road. It is an important rice trading market in Shexian county. It is known as the “village growing rice on the stone slab”. Ancient Architectural Buildings Along Ruoling ancient road and Jingshe ancient road, there are rich architectural heritages such as ancient pavilions, ancient bridges and ancient temples. Along the Ruoling section of Shexian County, there are Shuikou

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bridge, Yong’an bridge, Xia Erliban pavilion, Chatan bridge, Shang Erliban pavilion, Shili Bridge, Zhonglie temple and other architectural heritages. Along the Huangshan section of Ruoling ancient road, there are Tanjia Bridge and other ancient buildings, and along the Jingshe ancient road, there are Wuli pavilion and other ancient buildings (Tables 14.1 and 14.2). Xxx Table 14.1 List of heritage composition of Ruoling ancient road Composition

Creation era

Heritage overview

Shuikou bridge

Qing dynasty

The bridge span is about 8 m

Yongan bridge

Qing dynasty

The bridge span is about 5 m

Xia Erliban pavilion

Qing dynasty

The depth is 6.7 m and the width is 6.1 m

Chatan bridge

Qing dynasty

The bridge span is 2.5 m

Shang Erliban pavilion

Qing dynasty

The depth is 6.7 m and the width is 7.8 m

Shili bridge

Qing dynasty

The depth is 8.5 m and the width is 9.3 m

Zhonglie temple

Ming dynasty

The building area is 75.7 square meters

Ruoling pass

Qing dynasty

The door opening is 1.6 m wide, 3 m high and 13.3 m deep

Tanjia bridge

Ming-Qing dynasty

The bridge is about 100 m long and 8 m wide

Ledezuo nunnery site

Qing dynasty

Only ruins

Bali hillock

Qing dynasty

Only ruins, it used to be a post station

Qilong nunnery site

Qing dynasty

Only ruins, and the opposite is the tomb of Zen master

Table 14.2 List of heritage composition of Jingshe ancient road Composition

Creation era

Heritage overview

Wuli pavilion

Ming dynasty

The pavilion is 5.4 m long, 8.1 m wide and 3.3 m high

Tianxing cave

Ming dynasty

The hole is 7 m deep, 4 m wide and 2.7 m high

Wangzi cave

Ming dynasty

The hole is 7.6 m deep, 5 m wide and 3.7 m high

Tianzhu nunnery site

Ming dynasty

The site is 7.5 m deep and 10.1 m wide

Kaobi cave

Ming dynasty

The depth of the hole is 6.0 m, the width is 6.0 m, and the roll height is 5.1 m

Tathagata pillar Ming dynasty

The pillar is 2.95 m high and 1.18 m long

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14.3.3 Heritage Value Characteristics of Ruoling Ancient Road and Jingshe Ancient Road. Historical Value Ruoling ancient road and Jingshe ancient road are large-scale artificial commercial transportation system formed in the specific natural and social environment, which contains rich natural and humanistic information. For more than 1000 years, Ruoling ancient road and Jingshe ancient road have connected Huizhou and ningguofu. People come and go, and business travel is endless. In the process of the rise and development of Huizhou merchants, Ruoling ancient road and Jingshe ancient road are connected, It has played its role and witnessed the culture of Hui merchants for thousands of years, reflecting their persistent and meaningless pioneering spirit and strength, which has important historical value. Traffic Value Ruoling ancient road and Jingshe ancient road are the thoroughfares for the development of Huizhou. By land, it was connected to Taiping in the north to Anqing, the largest mansion in Anhui at that time; Northeast Jingde to ningguofu to Xuancheng. On the waterway, the shortcut connecting the Yangtze River system and Xin’anjiang river system is more important: to the north, it can reach the Lingbei Taihe River in Taiping County, through which the Yangtze River can be connected; To the south, you can reach the Fuzi River in shebei, and through the Fuzi river you can reach Xin’anjiang, which makes it convenient to “connect Zhejiang Province by southeast waterway”. The establishment of these two water systems has broken the traffic bottleneck of Huizhou to all parts of the country. Military Value During the movement of Taiping Heavenly Kingdom in Xianfeng Period of Qing Dynasty, Taiping army passed through Ruoling several times; On December 14, 1934, Fang Zhimin led the advance team of the Red Army going northward to resist Japanese aggression in a fierce battle with Wang Yaowu’s troops of the Kuomintang in the area of Shimen, Tanjiaqiao. One day, xunhuaizhou, the commander of the 19th division, was seriously injured and died on the way of transfer. Huang Yingte, the head of the 87th regiment, was killed. Nearly 8000 Red Army troops withdrew from the battle safely and orderly and moved smoothly; On the 25th, Fang Zhimin led the advance team of the Red Army going northward to Xu village from Tangkou via Ruoling to carry out Anti Japanese propaganda activities; On April 28, 1949, Li Desheng led the 35th division of the 12th army of the second field army of the Chinese people’s Liberation Army from Ruoling to Xucun, liberated Shexian county. Ruoling ancient road and Jingshe ancient road record the indomitable spirit of the Chinese people in the war of resistance against Japan and the heroic spirit of liberating the whole of China, which has important revolutionary value. Research Value Ruoling ancient road and Jingshe ancient road were excavated by Wang Hua, the Duke of Yue, and were elected as the county guards of Xin’an. They conquered Xuancheng, Yuhang, sui’an, Dongyang and Poyang to protect the six prefectures. Later, they were granted the title of Duke of Yue by Emperor Gaozu of Tang Dynasty. After Hong, they became the God of fighting against drought and

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disaster in Huizhou, The loyalty of the Duke of Yue built under Ruoling pass has a history of nearly 500 years. Up to now, there are still the customs of offering sacrifices and carrying the Duke of Wang in the villages near Ruoling pass. The blue and white stones of Ruoling ancient road and Jingshe ancient road were transported from Zhejiang tea garden through Xin’an River. They are called “tea garden stone”. In ancient Shexian county and other places, all the students and Juren rushed through this road. In order to seek good luck, they were homonymous as “Zhuangyuan stone”. Therefore, Ruoling ancient road and Jingshe ancient road have important research value in material heritage and intangible cultural heritage.

14.4 Protection and Utilization of Huizhou Ancient Road 14.4.1 Comprehensive Investigation of Huizhou Ancient Road Cultural Route Heritage Resources We will comprehensively carry out the general survey of Huizhou Ancient Road heritage resources including Ruoling ancient road and Jingshe ancient road, speed up the systematic investigation and collation of the basic data of Huizhou cultural route heritage such as ancient Huizhou Road, and systematically sort out the history and current situation of Huizhou ancient road. By using modern information technology such as three-dimensional space scanning, big data and geographic information system, we can collect and sort out the preservation and protection status of Huizhou Ancient Road, establish Huizhou ancient road database, and establish a complete scientific evaluation system of Huizhou Ancient Road value.

14.4.2 Constructing Ecological Protection Corridor of Huizhou Ancient Road The Huizhou Ancient Road, including the Ruoling Ancient Road and the Jingshe Ancient Road, is located in the mountainous area of southern Anhui. In the process of route selection and construction, great attention is paid to the combination with the mountain environment, and its layout has a good ecological foundation. However, in recent years, due to natural disasters such as landslides and mudslides, as well as long-term disrepair, the Huizhou Ancient Road and its surrounding environment have been damaged. In combination with the construction of Huizhou cultural ecology Reserve, the cultural and ecological corridor space of Huizhou ancient roads will be constructed. Protect the mountain environment, prohibit activities such as mining forests, destroying forests, and planting tea in the ancient Huidao area, restore the ecological

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environment of ecologically fragile mountain areas, ensure the geological safety of the ancient Huidao area, and reduce the damage of geological disasters to the ancient Huidao. At the same time, it is necessary to deeply explore the typical value of the ancient emblem road and related affiliated heritage, enrich and improve the living habits, traditional technologies, production skills, farming methods, etiquette and customs, religious beliefs, as well as intangible cultural connotations such as local dialects, traditional clothing, architectural styles and construction techniques, village structures, etc. in the area of the ancient emblem road, and combine modern technology for reasonable display and promotion, continuously expanding its cultural extension.

14.4.3 Building a Complete Protection System of Huizhou Ancient Road Ruoling ancient road, Jingshe ancient road and the villages along them have profound cultural heritage and rich heritage composition. Gradually carry out the research on the protection technology of ancient Huizhou Road, including the research on the relevant theories and construction techniques of ancient Huizhou Road, improve the protection system at different levels, and deeply excavate its typical value according to the historical archives and preservation status of ancient Huizhou road, To apply for national key cultural relics protection units, provincial cultural relics protection units, city and county cultural relics protection units, etc., and form a complete protection system of ancient Huizhou Road, which is “city and county protection—provincial protection—national protection—World Heritage”.

14.4.4 Promote the Rational Use of Huizhou Ancient Roads Rational utilization is an important part of the protection of cultural relics and historic sites. According to the value, characteristics, preservation status and environmental conditions of cultural relics and historic sites, we should comprehensively consider various utilization methods of research, display, continuation of the original functions and giving cultural relics and historic sites appropriate contemporary functions. The utilization should emphasize the public interest and sustainability, and avoid over utilization (National Committee of China, International Council on Monuments and sites. Guidelines for the protection of cultural relics and historic sites in China 2015). In the utilization of Huizhou Ancient Road, we should give full play to its social value, carry out various outdoor experiential activities in combination with tourism development and outdoor fitness, and strengthen the dissemination of ancient road culture through exhibition facilities.

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14.5 Epilogue As an important heritage of Huizhou cultural route, Ruoling ancient road and Jingshe ancient road have played an important role of transportation in history, and left us rich material and intangible cultural heritage. We should study and protect the ancient road and its affiliated heritage from the perspective of heritage corridor, and fully explore the modern utilization function of the ancient road, In the protection of the use, in the use of the inheritance of Huizhou profound regional culture. Acknowledgements This paper has been supported by the MOE (Ministry of Education of the People’s Republic of China) Youth Fund Project of Humanities and Social Sciences (Project No.18YJC850002). Anhui Innovative Province Construction Subsidy Fund Special Funding Project (2020xzx001). Huizhou Culture Integration Course Teaching and Research Special Key Project of Huangshan University (2020HWJY02). Teaching Research Project of Anhui Provincial Department of Education (2020jyxm1778). “10303 plan of Huizhou research talents training” project of Huangshan Social Science Federation, Anhui Province.

References Jinlong C, Han L et al (2018) Spatial distribution and evolution of traditional villages in ancient Huizhou. J Anhui Jianzhu Univ 26(3):26–34 National Committee of China, International Council on Monuments and sites. Guidelines for the protection of cultural relics and historic sites in China (revised in 2015). Heritage Publishing House, Beijing, October 2015 Yang Z, Qi C (2016) Status quo investigation and value research of Huizhou Ancient Road. J Huangshan Univ 18(4):6–10 Zhongsong B (2014) Analysis on the architectural form of Cheng’s three mansions in Huizhou ancient dwellings. J Henan Univ Sci Technol 42(5):29–33 Zhongsong B, Lili. W (2014) Analysis on the architectural form of Huizhou Dunhua hall ancient stage. J Yangtze Univ 11(29):15–18 Zhongsong B, Yunzhang L, Yanfeng L (2014) Architectural characteristics of Luo Dongshu ancestral hall in Huizhou ancient ancestral hall. J Shenyang Jianzhu Univ 16(4):345–352

Chapter 15

Effects of Polypropylene Fibers from Single-Use Facemasks on the Microstructure of Normal Cementitious Composites Aaron Paul I Carabbacan and Teodoro A. Amatosa

Abstract Cementitious composites (CC) have continuously advanced in recent years, owing to their abundant resources, well-established production methods, and remarkable versatility in civil engineering and construction applications. However, one aspect of CC that has received significant attention and improvement is its microstructure, primarily due to its inherent heterogeneity. At the microscale level, incorporating multiple independent polypropylene (PP) fibers into CC has demonstrated the potential to address its intrinsic weaknesses effectively. A novel research area involves integrating recycled PP fibers from single-use facemasks (SUF) into CC, producing environmentally friendly fiber-reinforced cementitious composites (FRCC) which can enhance microstructure characteristics. This study utilized locally available CC constituents combined with PP fibers sourced from SUF, resulting in a specimen with a fiber volume content of 0.40%. Scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) were employed to analyze the microstructure and elemental composition of the specimen. The findings indicate that incorporating PP fibers from SUF resulted in notable improvements in the CC microstructure than the adjacent host cementitious matrix by producing a denser cement matrix, effectively reducing micropores and voids, exhibiting smaller microcracks, and establishing good fiber-matrix compatibility. Keywords Face mask · Microstructure · Polypropylene fiber · ITZ · SEM · Cementitious composites A. P. I. Carabbacan (B) · T. A. Amatosa Polytechnic University of the Philippines, Sta. Mesa Manila, Philippines e-mail: [email protected] T. A. Amatosa e-mail: [email protected] A. P. I. Carabbacan Colegio de Muntinlupa, Sucat Muntinlupa City, Philippines T. A. Amatosa Northwest Samar State University, Calbayog, Samar, Philippines © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_15

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15.1 Introduction Cementitious composites (CC) have been among the most enhanced infrastructure construction materials because of their readily accessible resources, established manufacturing methods, and exceptional adaptability (Prokopski and Halbiniak 2000; Gencel et al. 2011; Wang and Jivkov 2015; Koniorczyk et al. 2022; Vafaei et al. 2023). The multiscale structure of CC significantly influences its physical characteristics, mechanical behavior, and durability properties, making it essential to study the complex processes surrounding its constituents while considering heterogeneity (Thilakarathna et al. 2020; Banaay et al. 2023). On the microscale, incorporating multiple unconnected polymeric fibers into CC can significantly enhance its innate weaknesses (Tran et al. 2022). Polypropylene (PP) is a remarkable polymeric fiber reinforcement that can enhance the physical, mechanical, durability, and microstructural properties of CC (Tran et al. 2022; Akid et al. 2021), making it the most frequently utilized fiber material in CC due to its resilience to a range of chemicals, low cost, lightweight, and ease of production (Menyhárd et al. 2020). Due to the simultaneous challenge of disposal management, adverse environmental effects, the COVID-19 pandemic, and sustainability for construction materials, PP derived from waste plastics like discarded facemasks are of significant concern (Ahmed et al. 2021; Fadare and Okoffo 2020; Jiang et al. 2023; Selvaranjan et al. 2021). The utilization of PP in CC has captivated the interest of the construction industry and academics, owing to its numerous sustainability implications. Due to the heterogeneity of CC, the impacts of fibers on its characteristics are usually laborious to discern. The specific fiber that must be utilized in CC is determined mainly by its application (Hannawi et al. 2016). The fibers can be identified by their varied physical or chemical characteristics, such as their material nature (Rohollah et al. 2022), type (Latifi et al. 2022), geometry and configuration (Pakravan and Memariyan 2017), size and aspect ratio (Mazzoli et al. 2015), mechanical strength (Blazy and Blazy 2021), manufacturing method, and so on. Consequently, the fibers can affect the interfacial transition zone (ITZ) microstructure, the host cementitious matrix, and the bonding between the aggregate-cementitious matrix and the fiber-cementitious matrix (Gao et al. 2014; Yuan and Jia 2021). On the microscopic scale, most structural discontinuities originate in the ITZ amid the coarse granular aggregate and the cement paste (Golewski 2018), and this region is regarded as the weakest location in CC structures by much prior research (Prokopski and Halbiniak 2000). The ITZ begins at the surface of the distinct aggregate or the fiber and extends into the matrix with variations in numerous matrix material parameters such as water/binder ratio, porosity, degree of hydration, hydrate composition, and so on (Eik et al. 2020). Typically, the width of the porous aggregate-cement ITZ is between 20 and 50 µm (Skar˙zy´nski et al. 2015). In addition, the width of the more porous fiber-cement ITZ ranges from 15 to 30 µm and depends on the fiber size due to the wall effect (Xu et al. 2017). Prior recent studies on facemasks incorporation in ordinary CC can prevent microcracks progression up to 2% PP fiber volume

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with 0.4% PP fiber volume incorporation may enhance its mechanical strength and durability characteristics (Aal et al. 2022; Miah et al. 2023; Idrees et al. 2022). At present, plastic production in factories has increased dramatically worldwide. Specifically, facemask production on diverse plastic materials expanded continually due to the COVID-19 worldwide pandemic and was essential for personal health even in the post-pandemic age (Selvaranjan et al. 2021). The environmental consequences are only expected to worsen as the bulk of the unused, expired, and used facemasks wind up on the streets or landfills (Saberian et al. 2021; Sangkham 2020). Authorities and the general population have indeed undertaken to investigate alternate options such as the recycling, repurposing, and disinfecting of disposable masks, as well as the production of biodegradable masks and handmade masks (Rubio-Romero et al. 2020). The most utilized discarded facemasks are composed of PP plastic (Akber Abbasi et al. 2020; Chen et al. 2021; Wang et al. 2022). Incorporating PP facemasks in CC can be a sustainable approach to enhance its microstructural characteristics and reduce negative environmental impacts such as waste pollution and improper disposal management of discarded products. A new study field is the incorporation of recycled PP fibers derived from single-use facemasks (SUF) to CC to produce environmentally friendly fiber-reinforced cementitious composites (FRCC). Very few research investigations have been published so far that have evaluated the fundamental characteristics of CC and other construction materials incorporating solely facemask fibers (Koniorczyk et al. 2022; Saberian et al. 2021; Wang et al. 2022; Kilmartin-Lynch et al. 2021; Ahmed and Lim 2022). Furthermore, this study is an approach to employing PP facemasks to enhance the microstructure of CC.

15.2 Methodology The researcher produced a normal-weight CC specimen comprising the following constituents: cement paste, fine and coarse aggregates, and 0.40% PP fibers from SUF. The test data for the characterization of the hydraulic cement and the aggregates were provided by Megawide Batching Plant. The details of the CC materials used are presented in Sect. 2.1.

15.2.1 Constituent Materials Cement The CC specimen employed Type I ordinary Portland cement (CEM-I 34.0 N) in compliance with ASTM C150 with a specific gravity of 3.14. The chemical composition, physical qualities, and mechanical properties of the cement are presented in Table 15.1.

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Table 15.1 Characteristics of cement Chemical composition

Value (%)

ASTM requirement

MgO

1.9

6.0 (maximum)

SO3

1.9

3.0 (maximum)

Loss on ignition

1.9

3.0 (maximum)

Insoluble residue

0.4

0.75 (maximum)

Physical properties

Value

ASTM requirement

Autoclave expansion (%)

0.4

0.8 (maximum)

Specific gravity (g/cm3 )

3.14

Setting time (Vicat needle): Initial (min)

91

Final (min)

210

Normal consistency (%)

26.6

Fineness: % passing 200

4.7

Mechanical properties

45–375

Value (Ave.)

ASTM requirement

Three days

13.7

12.0 (minimum)

Seven days

23.3

19.0 (minimum)

Twenty-eight days

33.8

28.0 (minimum)

Compressive strength (MPa)

Aggregates The CC specimen contained crushed sand as fine aggregate with a maximum grain size of 4.75 mm. Crushed stone was utilized as coarse aggregate with a range size of 12–25 mm. Table 15.2 presents the physical properties of the fine and coarse aggregates. Fibers Owing to ongoing pandemic constraints, the researcher acquired discarded single-use polypropylene facemasks (SUPF), Type II, measuring approximately 175 mm long, 95 mm wide, and 0.25 mm thick from residential collections. The front and rear layers of the SUPF were composed of non-woven (SMS texture) PP fibers, while the middle filtration layer was melt-blown fabric (O’Dowd et al. 2020). Personal protective equipment (PPE), such as disposable nitrile gloves, a laboratory apron, and a medical mask, were required to be worn for gathering and handling the facemasks. The SUPF was pasteurized for 1 h at 70 °C using the dry heat process, as advised by Xiang et al. (2020). The metallic nose wire support and the two ear bands were dismantled to ensure uniformity of the incorporating fiber, similar to the methodology of Ahmed and Lim (2022). The SUPF were cut by ordinary scissors into appropriate rectangular strips, with lengths and widths of nearly 30 mm and 2.5 mm, respectively. Table 15.3 shows the material characteristics of the incorporating SUPF. Figure 15.1 depicts the SUPF manually cut-in strips and their dimensions.

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Table 15.2 Physical characteristics of fine and coarse aggregates Physical properties

Fine aggregate

Coarse aggregate

Unit weight (kg/m3 ) Loose, SSD

1449

1636

Rodded, SSD

1537

1752

Loose, Dry

1407

1620

1493

1735

Rodded, Dry

ASTM requirement C29

Mortar strength (%)

98

C87

Soundness loss (%)

2.5

C88

Abrasion loss (%)

21.4

C131

Clay lumps and friable particles (%)

0.4

C142 C127/C128

Specific gravity OD

2.36

2.63

SSD

2.43

2.65

Apparent

2.53

2.70

Absorption (%)

2.95

0.97

Fineness modulus

2.6

C127

15.2.2 Mixing Requirement and Casting Procedure To prepare the CC specimen, fine and coarse aggregates from the local area were combined with Portland cement at a fixed water-cement proportion of 0.61. The CC specimen has a design compressive strength of 24.1 MPa (3500 psi) and a design slump of 25–75 mm (1–3 in.). The CC mix design conformed to ACI 211. Table 15.4 provides the design mix proportions of constituent materials to produce the CC specimen. The constituents underwent a dry mixing process for one minute and added distilled water. The mixing procedure persisted for a duration of two minutes. After a brief pause of one minute, the mixing process recommenced for another two minutes. The prepared CC mixture was carefully poured into a cylindrical mold measuring 4 × 8 in. Subsequently, the specimen was demolded after a 24-h casting period and transferred to a laboratory environment, where it was immersed in room-temperature water for twenty-eight days.

15.2.3 Image Analysis and Elemental Characterization The microstructure of the CC specimen was studied using Field Emission Scanning Electron Microscopy (FESEM). The imaging was done at Advanced Device and Materials Testing Laboratory (ADMATEL-DOST) using the Dual Beam Helios

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Table 15.3 Material characteristics of incorporating SUPF fiber strips Material properties

References

Value

Standard

Specific gravity

Saberian et al. (2021), Kilmartin-Lynch et al. (2021)

0.91

ASTM D792

Melting point (°C)

Saberian et al. (2021), Kilmartin-Lynch et al. (2021)

160

ASTM D7138

Water absorption 24 h (%)

Saberian et al. (2021), Kilmartin-Lynch et al. (2021)

8.9

ASTM D570

Tensile strength (MPa)

Saberian et al. (2021), Kilmartin-Lynch et al. (2021)

4.25

ASTM D638

Tensile strength at break (MPa)

Saberian et al. (2021), Kilmartin-Lynch et al. (2021)

3.97

ASTM D638

Elongation at break (%)

Saberian et al. (2021), Kilmartin-Lynch et al. (2021)

118.9

ASTM D638

Rupture force (N)

Saberian et al. (2021), Kilmartin-Lynch et al. (2021)

19.46

ASTM D638

Material nature

Saberian et al. (2021), Kilmartin-Lynch et al. (2021)

Polypropylene

Mean fiber diameter (µm)

Sharma et al. (2022)

Length (mm)

7.8 30 ± 2

Width (mm)

2.5 ± 0.5

Thickness (mm)

0.25 ± 0.1

Aspect ratio

51–100

Fiber type

Monofilament

Fig. 15.1 Images of the SUPF fibers: a cut into strips; b strip dimensions

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Table 15.4 The mixture composition of CC incorporated with 0.40% PP fibers per cubic meter w/c

Cement (kg)

Water (kg)

Fine aggregate (kg)

Coarse aggregate (kg)

PP fiber (kg)

SP (%)

0.61

311.5

190.0

1025.2

873.3

9.6

N/A

Nanolab 600i with a FESEM accelerating voltage of 10.0 kV and a beam current of 0.69 pA. Two areas were imaged in the CC specimen. Additionally, Energy Dispersion Spectroscopy (EDS) was also conducted employing the same instrument, accelerating voltage, and beam current to characterize the chemical composition of the CC. Before the morphological examination, the specimen was reduced into smaller sizes of less than or equal to 10 mm × 10 mm × 10 mm cube and was sputter-coated with platinum (Pt) before analysis. The morphological analysis was conducted after 28 days upon casting.

15.3 Results and Discussion Figure 15.2 depicts the Energy Dispersive X-ray Analysis (EDX) spectrum for the distribution of elements of the host cementitious matrix and the incorporated 0.40% PP fibers from SUF embedded in the cementitious matrix of the CC specimen. The left spectrum (Fig. 15.2a) indicates a sharp intensity peak of oxygen (O), silicon (Si), and calcium (Ca) which represents the presence of hydrated cement and sand and shows the formation of calcium-silica-hydrate (CSH) gels. In addition, the high points in the right spectrum ((Fig. 15.2b) reflect the elements of the fibers and surrounding gels of CSH. The tall spikes of C and O indicate the elemental composition of the embedded SUF fibers made by PP bonded with CSH gels. Since no SCM was added, the PP fibers embedded in the cementitious matrix do not alter the microstructural characteristics and each constituent represents an independent influence on the microstructure of the CC specimen. The PP fibers from SUF altered the microstructural characteristics of CC owing to their action rather than modifications to their elemental structure similar to the characterization of Idrees et al. (2022). The microstructure of the CC with embedded PP fibers exhibits a significant enhancement compared to the microstructure of the adjacent host cementitious matrix. This improvement can be attributed to the deposition of a greater amount of hydrated products on the surface of the embedded PP fibers. The FESEM images in Fig. 15.3 show the microstructure of the CC specimen with 0.40% PP fiber content and its host cementitious matrix in its vicinity. CSH gels are often brighter in the shade, whereas the aggregates are darker, with fine aggregates as semi-dark particles. Figure 15.3a revealed the surface of the cementitious matrix consisted of diversified-sized particles and was covered with the presence of numerous micropores. Additionally, the surface topography is amorphous in shape.

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Fig. 15.2 EDX spectra and elemental composition: a the near host cementitious matrix; b incorporating PP fibers from SUF embedded to CC

Fig. 15.3 SEM micro-image of the CC specimen: (left) cementitious matrix vicinity showing larger microcracks and numerous micropores; (right) incorporated with PP fibers from SUF demonstrating microstructure quality, interfacial microcrack measurement, and fiber-matrix interaction

Contrariwise, the PP fiber ends from the SUPF strips that surface from the cementitious matrix in varied positions and dimensions are noticeable in Fig. 15.3b. Individual PP fibers are vividly distinguished from one another, although they were still collectively connected on the SUPF strips. Furthermore, a dense cementitious matrix was produced near the ITZ of the strips, with direct contact with the fiber interface. A combination of PP fiber branching happened when the SUPF strips are partially separated into strands and filamenting on the surface of the SUPF strips although the protruding ends were firmly attached to the cementitious matrix. However, the roots of the embedded PP fibers strips generated microcracks within the perimeter, which can be attributed to the orientation and distribution of the fibers. The analysis revealed that hydration products predominantly envelop PP fibers, making them less conspicuous similar to the study of Idrees et al. (2022). The image displays anomalous formations, which signify the entanglement or wrapping of CSH around embedded PP fibers from the SUF. Additionally, the EDS results indicate the presence of CSH on the surfaces of PP fibers. These findings demonstrate that all PP fiber content within the CC is effectively dispersed and thoroughly hydrated by

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CSH. Furthermore, the PP fibers from SUF contribute to an enhanced microstructure than the adjacent host cementitious matrix since this establishes excellent interaction with the cementitious matrix, shows a denser cementitious matrix, exhibits smaller and fewer micropores and voids, produces thinner microcracks, demonstrating good fiber-matrix compatibility.

15.4 Conclusion In this study, incorporating PP fibers from single-use facemasks on CC positively affected its microstructure. Therefore, it provided an environmentally friendly, sustainable polypropylene FRCC. From the results and discussions presented based on the images provided, the following conclusions are offered: 1. The energy dispersion spectroscopy analysis demonstrated elemental intensity peaks of calcium-silica-hydrate, showing the presence of cementitious matrix in the specimen and carbon and oxygen, illustrating the presence of polypropylene fibers from single-use facemasks surrounded by hydrates. The elemental composition of the fiber strips does not change the microstructure of the cementitious composite. The microstructure of the CC with embedded PP fibers exhibits a significant enhancement compared to the microstructure of the adjacent host cementitious matrix since a significant amount of hydrates bonded to the surfaces of the PP fibers. 2. The scanning electron microscopy images illustrate the microstructure of the cementitious composite embedded with polypropylene fibers from single-use facemasks. The microstructure composition significantly improved by incorporating SUPF fibers, resulting in reduced micropores, and producing a dense cementitious matrix near the PP fibers. However, due to the partial separation of the PP fibers from the strips, interfacial microcracks were generated from the roots of the PP fibers, although the produced microcracks had smaller widths than the microcracks within the vicinity of the adjacent host cementitious matrix.

References Ahmed W, Lim CW (2022) Effective recycling of disposable medical face masks for sustainable green concrete via a new fiber hybridization technique. Constr Build Mater 344:128245 Ahmed HU, Faraj RH, Hilal N, Mohammed AA, Sherwani AFH (2021) Use of recycled fibers in concrete composites: a systematic comprehensive review. Compos B Eng 215:108769 Akber Abbasi S, Khalil AB, Arslan M (2020) Extensive use of face masks during COVID-19 pandemic: (micro-)plastic pollution and potential health concerns in the Arabian Peninsula. Saudi J Biol Sci 27:3181–3186 Akid ASM, Hossain S, Munshi MdIU, Elahi MMA, Sobuz MdHR, Tam VWY, Islam MdS (2021) Assessing the influence of fly ash and polypropylene fiber on fresh, mechanical and durability properties of concrete. J King Saud Univ Eng Sci

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Banaay KMH, Dela Cruz OG, Muhi MM (2023) Engineered cementitious composites as a highperformance fiber reinforced material: a review. Int J GEOMATE 24(106):101–110 Blazy J, Blazy R (2021) Polypropylene fiber reinforced concrete and its application in creating architectural forms of public spaces. Case Stud Constr Mater 14:e00549 Chen X, Chen X, Liu Q, Zhao Q, Xiong X, Wu C (2021) Used disposable face masks are significant sources of microplastics to environment. Environ Pollut 285:117485 Eik M, Antonova A, Puttonen J (2020) Phase contrast tomography to study near-field effects of polypropylene fibres on hardened cement paste. Cement Concr Compos 114:103800 El Aal AA, Abdullah GMS, Qadri SMT, Abotalib AZ, Othman A (2022) Advances on concrete strength properties after adding polypropylene fibers from health personal protective equipment (PPE) of COVID-19: Implication on waste management and sustainable environment. Phys Chem Earth Parts A/B/C 128:103260 Fadare OO, Okoffo ED (2020) Covid-19 face masks: a potential source of microplastic fibers in the environment. Sci Total Environ 737:140279 Gao Y, De Schutter G, Ye G, Tan Z, Wu K (2014) The ITZ microstructure, thickness and porosity in blended cementitious composite: effects of curing age, water to binder ratio and aggregate content. Compos B Eng 60:1–13 Gencel O, Ozel C, Brostow W, Martínez-Barrera G (2011) Mechanical properties of self-compacting concrete reinforced with polypropylene fibres. Mater Res Innovations 15(3):216–225 Golewski GL (2018) An assessment of microcracks in the interfacial transition zone of durable concrete composites with fly ash additives. Compos Struct 200:515–520 Hannawi K, Bian H, Prince-Agbodjan W, Raghavan B (2016) Effect of different types of fibers on the microstructure and the mechanical behavior of ultra-high performance fiber-reinforced concretes. Compos B Eng 86:214–220 Idrees M, Akbar A, Mohamed AM, Fathi D, Saeed F (2022) Recycling of waste facial masks as a construction material, a step towards sustainability. Materials 15(5):1810 Jiang H, Luo D, Wang L, Zhang Y, Wang H, Wang C (2023) A review of disposable facemasks during the COVID-19 pandemic: a focus on microplastics release. Chemosphere 312:137178 Kilmartin-Lynch S, Saberian M, Li J, Roychand R, Zhang G (2021) Preliminary evaluation of the feasibility of using polypropylene fibres from COVID-19 single-use face masks to improve the mechanical properties of concrete. J Clean Prod 296 Koniorczyk M, Bednarska D, Masek A, Cichosz S (2022) Performance of concrete containing recycled masks used for personal protection during coronavirus pandemic. Constr Build Mater 324:126712 Latifi MR, Biricik Ö, Mardani Aghabaglou A (2022) Effect of the addition of polypropylene fiber on concrete properties. J Adhes Sci Technol 36(4):345–369 Mazzoli A, Monosi S, Plescia ES (2015) Evaluation of the early-age-shrinkage of Fiber Reinforced Concrete (FRC) using image analysis methods. Constr Build Mater 101:596–601 Menyhárd A, Menczel JD, Abraham T (2020) Polypropylene fibers. In: Thermal analysis of textiles and fibers. Elsevier, pp 205–222 Miah MJ, Pei J, Kim H, Sharma R, Jang JG, Ahn J (2023) Property assessment of an eco-friendly mortar reinforced with recycled mask fiber derived from COVID-19 single-use face masks. J Build Eng 66 O’Dowd K, Nair KM, Forouzandeh P, Mathew S, Grant J, Moran R, Bartlett J, Bird J, Pillai SC (2020) Face Masks and respirators in the fight against the COVID-19 pandemic: a review of current materials. Adv Future Perspect Mater 13:3363 Pakravan HR, Memariyan F (2017) Modification of low-surface energy fibers used as reinforcement in cementitious composites: a review. Polym-Plast Technol Eng 56(3):227–239 Prokopski G, Halbiniak J (2000) Interfacial transition zone in cementitious materials. Cem Concr Res 30:579–583 Rohollah R, Agnieszka JK, Almeida FCR (2022) Effect of superabsorbent polymers on microstructure and strength of blended cements mortars reinforced by polymeric fibre. CEMENT 9:100041

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Rubio-Romero JC, Pardo-Ferreira M, del C, Torrecilla-García JA, Calero-Castro S (2020) Disposable masks: disinfection and sterilization for reuse, and non-certified manufacturing, in the face of shortages during the COVID-19 pandemic. Saf Sci 129:104830 Saberian M, Li J, Kilmartin-Lynch S, Boroujeni M (2021) Repurposing of COVID-19 single-use face masks for pavements base/subbase. Sci Total Environ 769:145527 Sangkham S (2020) Face mask and medical waste disposal during the novel COVID-19 pandemic in Asia. Case Stud Chem Environ Eng 2:100052 Selvaranjan K, Navaratnam S, Rajeev P, Ravintherakumaran N (2021) Environmental challenges induced by extensive use of face masks during COVID-19: a review and potential solutions. Environ Challenges 3:100039 Sharma A, Omidvarborna H, Kumar P (2022) Efficacy of facemasks in mitigating respiratory exposure to submicron aerosols. J Hazard Mater 422:126783 Skar˙zy´nski Ł, Nitka M, Tejchman J (2015) Modelling of concrete fracture at aggregate level using FEM and DEM based on X-ray µCT images of internal structure. Eng Fract Mech 147:13–35 Thilakarathna PSM, Kristombu Baduge KS, Mendis P, Vimonsatit V, Lee H (2020) Mesoscale modelling of concrete—A review of geometry generation, placing algorithms, constitutive relations and applications. Eng Fract Mech 231:106974 Tran NP, Gunasekara C, Law DW, Houshyar S, Setunge S (2022) Microstructural characterisation of cementitious composite incorporating polymeric fibre: a comprehensive review. Constr Build Mater 335:127497 Vafaei D, Ma X, Hassanli R, Duan J, Zhuge Y (2023) Experimental study on cyclic flexural behaviour of GFRP-reinforced seawater sea-sand concrete slabs with synthetic fibres. Ocean Eng 273:114014 Wang X, Jivkov AP (2015) Combined numerical-statistical analyses of damage and failure of 2D and 3D mesoscale heterogeneous concrete. Math Probl Eng 2015:1–12 Wang G, Li J, Saberian M, Rahat MdHH, Massarra C, Buckhalter C, Farrington J, Collins T, Johnson J (2022) Use of COVID-19 single-use face masks to improve the rutting resistance of asphalt pavement. Sci Total Environ 826:154118 Xiang Y, Song Q, Gu W (2020) Decontamination of surgical face masks and N95 respirators by dry heat pasteurization for one hour at 70 °C. Am J Infect Control 48:880–882 Xu L, Deng F, Chi Y (2017) Nano-mechanical behavior of the interfacial transition zone between steel-polypropylene fiber and cement paste. Constr Build Mater 145:619–638 Yuan Z, Jia Y (2021) Mechanical properties and microstructure of glass fiber and polypropylene fiber reinforced concrete: an experimental study. Constr Build Mater 266:121048

Chapter 16

Advancements in Concrete Incorporation: Harnessing the Potential of Crumb Rubber Tires as Sustainable Alternatives to Fine Aggregates Franklyn F. Manggapis, Sanjie Dutt A. Kumar, Joe Robert Paul G. Lucena, Aaron Paul I. Carabbacan, and Orlean G. Dela Cruz

Abstract In the contemporary era, the accumulation of industrial waste has become a significant challenge, particularly the disposal of scrap rubber tires, which contributes to environmental degradation. To address this issue, utilizing discarded tires as essential components in construction materials has notable advantages. This research paper aims to provide a comprehensive overview of recent advancements in using crumb rubber tires as partial replacements for fine aggregates in construction projects. The paper covers important aspects such as the treatment and characterization of rubber tire waste, the influence of rubber content on material properties, and the impact of rubber on the design mix. By exploring these areas, the study seeks to establish a fundamental understanding of integrating rubber into concrete, ultimately enhancing the environmental sustainability of concrete in the construction industry.

F. F. Manggapis (B) Civil Engineering Department, Technological Institute of the Philippines - Quezon, 938 Aurora Blvd., Cubao, Quezon, Metro Manila 1109, Philippines e-mail: [email protected] F. F. Manggapis · S. D. A. Kumar · J. R. P. G. Lucena · A. P. I. Carabbacan · O. G. D. Cruz Graduate School, Polytechnic University of the Philippines, M.H. del Pilar Campus, Valencia, Santa Mesa, Manila, Metro Manila 1016, Philippines e-mail: [email protected] J. R. P. G. Lucena e-mail: [email protected] A. P. I. Carabbacan e-mail: [email protected] O. G. D. Cruz e-mail: [email protected] J. R. P. G. Lucena · A. P. I. Carabbacan Civil Engineering Department, Colegio de Muntinlupa, Posadas Ave., Sucat, Muntinlupa, Metro Manila 1770, Philippines © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_16

195

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This paper addresses the urgent need for sustainable waste management and construction practices by offering insights into innovative methods of incorporating crumb rubber tires. The presented findings and knowledge serve as a valuable resource for researchers, engineers, and policymakers dedicated to mitigating the adverse environmental effects of industrial waste while promoting eco-friendly construction materials and practices. Keywords Crumb rubber tires · Concrete · Sustainability · Review

16.1 Introduction Concrete, known for its advantageous properties, is a fundamental material in construction (Nagarajan et al. 2020). In spite of that, extensive cement production has raised environmental issues, such as depletion of natural resources and the emission of carbon dioxide. Consequently, researchers are actively seeking new environmentally friendly alternatives. Many studies have explored the use of construction, agricultural, and industrial waste as substitutes for concrete materials. While incorporating recycled elements into concrete is crucial for enhancing sustainability, it can impact the mechanical properties of the resulting concrete (Alawais and West 2019). Nevertheless, these disadvantages can be mitigated by employing specific treatment to compensate for the property losses caused by the presence of recycled elements. A captivating area of study explores the potential utilization of crumb rubber tires as a substitute for aggregates. The environmental challenges associated with disposing of used tires in landfills are significant. These challenges include the risk of uncontrolled fires that emit harmful pollution, the creation of mosquito breeding grounds, and the release of hazardous chemicals that can contaminate the ecosystem, soil, and vegetation (Abd-Elaal et al. 2019). Consequently, the recycling of discarded tires for incorporation as aggregates in concrete has garnered considerable interest among researchers. This paper aims to evaluate the effectiveness of utilizing recycled crumb rubber tires as a substitute for traditional aggregates in concrete. By addressing the environmental issues linked to tire disposal and examining the advantages and limitations of incorporating crumb rubber tires into concrete, this study seeks to contribute to the continuous pursuit of sustainable construction materials.

16.2 Review Methodology The research methodology for this paper involves a systematic literature review, as defined by Kitcharoen (2005) and influenced by the framework proposed in Tranfield et al. (2003). The methodology comprises three phases: (a) research question formulation, (b) review execution, and (c) presentation of review.

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16.2.1 Research Questions A well-formulated research question is fundamental to conducting a high-quality study as it facilitates information gathering, problem understanding (Ratan et al. 2019), topic identification, and methodological guidance (dela Cruz and Ongpeng 2022). The study aims to analyze existing research on rubber concrete, resulting in the formulation of a general inquiry: “What are the recent advancements in integrating crumb rubber tires into concrete, and how do these environmentally sustainable alternatives compare to conventional fine aggregates in terms of their impact on the environment and mechanical properties?” Based on this overarching question, the researchers have derived specific inquiries. RQ#1: What are the treatment methods for crumb rubber tires in concrete? RQ#2: What is the impact of incorporating crumb rubber tires as fine aggregate in concrete on its mechanical and physical properties? RQ#3: What is the optimal design mix, proportions, and permissible rubber content for concrete?

16.2.2 Review Execution In order to identify relevant publications or journals pertaining to the topic, a systematic approach was employed, encompassing the following steps: (1) establishment of a comprehensive keyword list, (2) rigorous database search, and (3) meticulous documentation of the selected papers. The initial step involved the formulation of a set of specific keywords. Preferred Reporting Items for Systematic reviews and MetaAnalyses (PRISMA) guidelines (Moher et al. 2009) were utilized. These guidelines outline a systematic and standardized approach to literature review, thus ensuring the validity and reliability of the study findings. Figure 16.1 provides a visual representation of the documented papers, based on their eligibility and relevance to the research topic. Upon completion of the database search, a total of 55 journals and proceedings indexed in Scopus were obtained. To eliminate duplication, two duplicate documents were excluded from the dataset, resulting in a final pool of 53 unique papers. Through meticulous scrutiny, 20 papers were subsequently excluded from the analysis due to various reasons, including their lack of direct relevance to the research question, their classification as literature reviews, their partial replacement of crumb rubber tires with coarse aggregates, or other factors such as the utilization of rubber tires as supplementary materials within concrete mixtures. By employing this rigorous methodology, a refined collection of 33 papers was identified, representing the most pertinent and high-quality sources for this study.

F. F. Manggapis et al.

Papers identified using “Google Scholar.” n = 55

Papers screened by its content. n = 53

Papers check for its eligibility. n = 33

Included

Eligibility

Screening

Identification

198

Excluded: Duplicates: n =2 Excluded: Not related to research question: n =13 Used as Coarse Aggregates: n=4 Others: n=3

Paper Included for review n = 33

Fig. 16.1 Process of selecting articles

16.3 Crumb Rubber Treatment Many researchers have found that chemical and heat methods can be used to treat crumb rubber tires. The subsequent information provides a summary of each examined article, categorized by the type of treatment utilized.

16.3.1 Treatment of Rubber Tires Using Chemical Methods Shredded rubber tires underwent a treatment using sulfur compounds derived from the waste of petroleum plant, resulting in improved mechanical properties, especially in terms of its strength. The process involved immersing the rubber tires in carbon disulfide (CS2 ) and air drying it at control temperature. The introduction of CS2 modified the surface tension of the crumb rubber, leading to enhanced strength in concrete. Reinforced concrete beams displayed increased bending resistance as well (Yehia and Emam 2018). Alkali-treated crumb rubber material was found to overcome its drawbacks in concrete. Compared to untreated rubber, a one-day concrete sample exhibited a remarkable strength improvement of 51% in compressive strength and 59% in flexural strength. The effectiveness of the treated specimen increased over time, with

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the most significant impact observed in flexural strength rather than compressive strength. Incorporating crumb rubber into concrete mixes led to a 33% reduction of CO2 emissions, when replacing 15% of the aggregates with rubber. Interestingly, the emission reduction remained consistent regardless of the amount of rubber used (Ameri et al. 2020). In a distinct examination (Si et al. 2017), researchers delved into the resilience of rubber concrete when treated with a sodium hydroxide (NaOH) solution. To facilitate a meaningful comparison, they employed both natural crumb rubber and NaOH-treated rubber as substitutes for a portion of the fine aggregate in the concrete mixture. Notably, rubberized concrete displayed a higher air-void content compared to conventional concrete. However, when samples with equivalent levels of aggregate replacement were evaluated, those incorporating NaOH-treated rubber exhibited a slight reduction in air content compared to those with untreated rubber aggregate.

16.3.2 Treatment of Rubber Tires Using Thermal Methods In a noteworthy investigation cited in Abd-Elaal et al. (2019), it was revealed that subjecting crumb rubber to high temperatures prior to its incorporation into concrete yields two significant outcomes: the elimination of surface contaminants and the reinforcement of the rubber particles’ surface. These effects lead to enhancements in both the interface between rubber and concrete, as well as stress transfer. The efficacy of the heat treatment technique relies on the size of the rubber particles, with smaller particles displaying a greater potential for enhancing compressive and tensile strengths. Impressively, even after undergoing rigorous compression tests, the thermally treated rubber particles maintain their adherence to the matrix of concrete mixing.

16.4 The Effect of Crumb Rubber Tires to concrete’s Properties The focal point of this section centers on the transformative effects that arise from integrating crumb rubber tires into concrete, specifically within the realms of fresh and hardened states of the material. Through an extensive analysis of existing literature, valuable insights can be gleaned regarding the advantages and ramifications associated with this sustainable and innovative approach in concrete construction endeavors.

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16.4.1 Fresh Concrete—Workability The workability of concrete plays a crucial role in assessing the suitability of waste materials for potential inclusion in concrete mixtures. In a study conducted by Gupta et al. (2014), an optimal dosage of a HRWA was utilized in conjunction with rubber waste. This research emphasizes the relationship among admixture mixes, compaction factor, and rubber ash content in each concrete sample. The findings reveal that as the admixture increases, there is a corresponding need to increase the rubber ash content. Achieving a compaction factor above 0.9 required meticulous utilization of the admixture to maintain the desired level. However, when using a water-to-cement ratio of 0.35 and replacing 20% of fine aggregates with rubber ash, sustaining the compaction factor became challenging.

16.4.2 Hardened Concrete—Compressive Strength and Flexural Tensile The utilization of tire rubber ash as a replacement for fine aggregates yielded notable enhancements in concrete properties, as observed by Al-Akhras and Smadi. Substituting up to 10% of the fine aggregates with tire rubber ash resulted in an increase in compressive strength. After 90 days, the mortar specimens exhibited significant improvements in compressive strength, with increases from 14 up to 45% (Al-Akhras and Smadi 2004). Farhan et al. (2016) discovered that introducing rubber particles into a cement stabilized aggregate mixture resulted in decreased tensile strength, primarily due to the inherent weakness of these particles.

16.5 The Effect of Crumb Rubber Tires to concrete’s Properties Concrete, a widely used construction material known for its strength, stiffness, and durability, undergoes a process called hydration when its essential components of cement, water, and aggregates are combined, resulting in hardened mixtures (Zheng et al. 2008). Over time, additional components have been incorporated to enhance concrete’s workability, durability, and strength (Chandramouli et al. 2010; Bogdanov and Ibragimov 2017; Adinna et al. 2019). Moreover, there has been a growing emphasis on reducing greenhouse gases and reusing environmental waste through the partial replacement of raw materials (He et al. 2021; Bhogayata and Arora 2018; Vijayakumar et al. 2013; Raheem et al. 2012; Shahmansouri et al. 2020), which is the focus of this paper. To ensure the successful application of concrete, it is crucial to determine the appropriate quantities of raw materials through concrete mix design (Mir and Nehme

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2017). Concrete mix design involves the selection of raw materials and requires a comprehensive understanding of various specialized considerations. Meeting the required strength and building standards ensures the safe utilization of structures (Kalpana and Tayu 2020). This study focuses on assessing the potential of utilizing crumb rubber tires as a replacement for fine aggregates. Numerous studies, comprising over 33 publications, have extensively examined 309 concrete mixes, encompassing a wide range of raw materials and characteristics. These investigations encompassed various rubber types and sizes, watercement ratios, admixtures, and pretreatment methods, as detailed in Table 16.2. In the pursuit of finding sustainable solutions, crumb rubber (CR), derived from recycling discarded tires, has gained significant attention. The proper utilization of CR is a pressing research concern, considering its negative impact on air pollution through arson decomposition (Ziolkowski and Niedostatkiewicz 2019) and landfill accumulation (Youssf et al. 2016). Table 16.2 categorizes waste rubber tires based on their application and sizes (Segre and Joekes 2000). While crumb rubber tires fall within acceptable sieve size limits (ASTM C33, C33M–18 2018), the size of rubber particles greatly affects concrete outcomes. Rubber powder, for instance, enhances cement brittleness (Siddique and Naik 2004), whereas incorporating crumb rubber aggregates increases the potential for corrosion in concrete (Savas et al. 1997). Compressive strength is a crucial parameter for evaluating the quality of concrete, widely used in testing concrete mixtures (Zhang and Gao 2018). While other mechanical and physical properties provide a comprehensive understanding of concrete performance, compressive strength remains the primary indicator. As shown in Table 16.2, an evident trend emerges where increasing rubber content leads to a significant decrease in compressive strength. This can be attributed to the lighter nature of crumb rubber compared to sand (Gupta et al. 2019; Mousavimehr and Nematzadeh 2019). The target compressive strength for rubber concrete, as indicated in Table 16.2, is typically 40 MPa. However, the average compressive strength achieved at 28 days, with an average rubber content of 18%, is 23 MPa. Achieving the optimal concrete mix design has long been a challenge for engineers, given the multitude of variables involved (Abdelmonem et al. 2019). Interestingly, the findings from the collected papers often present conflicting views on the ideal mix. For instance, one study suggests that replacing at least 8% of fine aggregates with CR meets code requirements, while another indicates that a 3% CR content yields the highest compressive strength and enhances durability (Yang et al. 2018). Moreover, one research study recommends a concrete mixture with 30% rubber content specifically suited for vulnerable structures such as bridges. On the other hand, another study proposes that a partial replacement of fine aggregates with up to 4% rubber content is feasible (Siddique and Naik 2004) (Table 16.1).

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Table 16.1 Rubber waste categories Rubber tires waste

Sizes/Uses/Application

1. Scrap tires

Typical waste tires from automobile vehicles

2. Slit-tires

Resulted from machine typically by a sharp object

3. Shredded tires

300–460 mm in length by 100–230 mm wide, down to as small as 100–150 mm (4–6 in.) in length

4. Ground rubber

19–0.15 mm

5. Crumb rubber

4.75 to less than 0.075 mm

16.6 Conclusion Upon reflection, numerous studies have investigated the partial replacement of fine aggregates in concrete mixtures with rubber, yielding varying outcomes. However, the advancement of rubberized concrete is noteworthy, considering that the optimal concrete mix or acceptable content of rubber tire waste often differs due to criteria, functional requirements, and other factors affecting concrete performance. This study yields the following key conclusions: 1. The treatment of crumb rubber tires, specifically using NaOH, emerges as a significant factor in enhancing the strength and durability of the concrete mixture, particularly the compressive strength. 2. Pre-heating rubber tires prior to mixing enhances the interface between rubber and concrete, optimizing stress transfer for improved performance. 3. The effect of rubber content on compressive strength shows promise, with certain studies demonstrating substantial strength gains. However, the optimal rubber content remains inconsistent across different investigations. 4. Concrete mixes containing rubber content exhibit reduced workability due to the lightweight and porous nature of rubber. 5. The incorporation of rubber content as a partial replacement for fine aggregates contributes to a significant reduction in carbon dioxide emissions. However, the cost-effectiveness of utilizing rubber tires remains uncertain, warranting further examination in future studies. Overall, these findings underscore the potential of rubber-concrete composites while highlighting areas that require additional research and development.

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Table 16.2 Mixtures incorporating rubber content from diverse research investigations Authors

Year

Size of rubber (mm)

Rubber content (%)

Highest f’c, psi recorded

Mix design, psi

Liu et al. (2016)

2013

0.075–4.75

15, 25, and 100

4600

4300

Thomas et al. (2014)

2014

0.6, 0.8–2, 2–4 2.5–20, interval of 2.5

6100

4300

Senin et al. (2017)

2016

2–4

5–20, interval of 5

5000

4300

Day (2006)

2016

1.18, 2.36

20

7700

7200

Yang et al. (2018)

2017

0.16

3–7, interval of 2 7300

5800

Awan et al. (2021)

2018

0.6

4.5–5.5, interval of 0.5

5000

4300

Siddique and Naik (2004)

2018

0.177

1–30, various ranges

7000

6500

Bisht and Ramana (2017)

2019

2–5

10–40, interval of 10

7300

7200

Aslani and Khan (2019)

2019

0.4–0.8

2, 40, and 60

5600

5000

Li et al. (2019) 2019

0.1–6.5

12.5, 25, 50, and 75

7700

7300

Mousavimehr and Nematzadeh (2019)

2019

0–1. 1–4

10–30, interval of 10

9900

8700

Savas et al. (1997)

2019

0.15–1.9

5–25, interval of 5

7300

7300

Zhang and Gao (2018)

2019

0.075–2.36

15 and 30

7700

7300

Youssf et al. (2020)

2020

0.177

3–15, interval of 5

3700

4300

Venkatesan et al. (2020)

2021

0.075–3.75

5–20, interval of 5

3300

3000

References Abd-Elaal E-S, Araby S, Mills JE, Youssf O, Roychand R, Ma X, Zhuge Y, Gravina RJ (2019) Novel approach to improve crumb rubber concrete strength using thermal treatment. Constr Build Mater 229:116901 Abdelmonem A, El-Feky MS, Nasr E-SAR, Kohail M (2019) Performance of high strength concrete containing recycled rubber. Constr Build Mater 227:116660 Adinna BO, Nwaiwu CMO, Igwagu CJ (2019) Effect of rice-husk-ash admixture on the strength and workability of concrete. Niger J Technol 38:48

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Al-Akhras NM, Smadi MM (2004) Properties of tire rubber ash mortar. Cement Concr Compos 26:821–826 Alawais A, West RP (2019) Ultra-violet and chemical treatment of crumb rubber aggregate in a sustainable concrete mix. J Struct Integr Maintenance 4:144–152 Ameri F, Shoaei P, Reza Musaeei H, Alireza Zareei S, Cheah CB (2020) Partial replacement of copper slag with treated crumb rubber aggregates in alkali-activated slag mortar. Constr Build Mater 256:119468 Aslani F, Khan M (2019) Properties of high-performance self-compacting rubberized concrete exposed to high temperatures. J Mater Civil Eng 31 ASTM C33/C33M-18. Standard specification for concrete aggregates Awan HH, Javed MF, Yousaf A, Aslam F, Alabduljabbar H, Mosavi A (2021) Experimental evaluation of untreated and pretreated crumb rubber used in concrete. Crystals (Basel) 11:558 Bhogayata AC, Arora NK (2018) Workability, strength, and durability of concrete containing recycled plastic fibers and styrene-butadiene rubber latex. Constr Build Mater 180:382–395 Bisht K, Ramana PV (2017) Evaluation of mechanical and durability properties of crumb rubber concrete. Constr Build Mater 155:811–817 Bogdanov RR, Ibragimov RA (2017) Process of hydration and structure formation of the modified self-compacting concrete. Mag Civil Eng 5:14–24 Chandramouli K, Srinivasa Rao P, Sravana S, Tirumala S, Narayanan P (2010) Strength properties of glass fiber concrete. ARPN J Eng Appl Sci 5 Day KW (2006) Concrete mix design, quality control and specification. CRC Press dela Cruz OG, Ongpeng JMC (2022) Building information modeling on construction safety: a literature review. Adv Architect Eng Technol 89–102 El Mir A, Nehme SG (2017) Utilization of industrial waste perlite powder in self-compacting concrete. J Clean Prod 156:507–517 Farhan AH, Dawson AR, Thom NH (2016) Characterization of rubberized cement bound aggregate mixtures using indirect tensile testing and fractal analysis. Constr Build Mater 105:94–102 Gupta T, Chaudhary S, Sharma RK (2014) Assessment of mechanical and durability properties of concrete containing waste rubber tire as fine aggregate. Constr Build Mater 73:562–574 Gupta T, Siddique S, Sharma RK, Chaudhary S (2019) Behaviour of waste rubber powder and hybrid rubber concrete in aggressive environment. Constr Build Mater 217:283–291 He R, Yang Z, Gan VJL, Chen H, Cao D (2021) Mechanism of nano-silica to enhance the robustness and durability of concrete in low air pressure for sustainable civil infrastructures. J Clean Prod 321:128783 Kalpana M, Tayu A (2020) Experimental investigation on lightweight concrete added with industrial waste (steel waste). Mater Today: Proc 22:887–889 Kitcharoen K (2005) The importance-performance analysis of service quality administrative departments of private universities in Thailand. J Bus Manage Market Tourism Hospital Fin Econ 4:20–46 Li H, Xu Y, Chen P, Ge J, Wu F (2019) Impact energy consumption of high-volume rubber concrete with silica fume. Adv Civil Eng 2019:1–11 Liu H, Wang X, Jiao Y, Sha T (2016) Experimental investigation of the mechanical and durability properties of crumb rubber concrete. Materials 9:172 Moher D, Liberati A, Tetzlaff J, Altman DG (2009) Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med 6:e1000097 Mousavimehr M, Nematzadeh M (2019) Predicting post-fire behavior of crumb rubber aggregate concrete. Constr Build Mater 229:116834 Nagarajan Prasad N, Sudha J, Diwahar A (2020) WITHDRAWN: an exploratory analysis on prejudice substitute of fine aggregate by glass powder and crumbed rubber on M30 concrete. Mater Today: Proc (2020) Raheem AA, Olasunkanmi BS, Folorunso CS (2012) Saw Dust ash as partial replacement for cement in concrete. Org Technol Manag Constr: Int J 4

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Ratan S, Anand T, Ratan J (2019) Formulation of research question—Stepwise approach. J Ind Assoc Pediat Surgeon 24:15 Savas BZ, Ahmad S, Fedroff D (1997) Freeze-thaw durability of concrete with ground waste tire rubber. Transport Res Rec: J Transport Res Board 1574:80–88 Segre N, Joekes I (2000) Use of tire rubber particles as addition to cement paste. Cem Concr Res 30:1421–1425 Senin MS, Shahidan S, Leman AS, Othman N, Shamsuddin S, Ibrahim MHW, Mohd Zuki SS (2017) The durability of concrete containing recycled tyres as a partial replacement of fine aggregate. IOP Conf Ser: Mater Sci Eng 271:012075 Shahmansouri AA, Akbarzadeh Bengar H, Ghanbari S (2020) Compressive strength prediction of eco-efficient GGBS-based geopolymer concrete using GEP method. J Build Eng 31:101326 Si R, Guo S, Dai Q (2017) Durability performance of rubberized mortar and concrete with NaOHsolution treated rubber particles. Constr Build Mater 153:496–505 Siddique R, Naik TR (2004) Properties of concrete containing scrap-tire rubber—An overview. Waste Manage 24:563–569 Thomas BS, Gupta RC, Kalla P, Cseteneyi L (2014) Strength, abrasion and permeation characteristics of cement concrete containing discarded rubber fine aggregates. Constr Build Mater 59:204–212 Tranfield D, Denyer D, Smart P (2003) Towards a methodology for developing evidence-informed management knowledge by means of systematic review. Br J Manag 14:207–222 Venkatesan G, Saravanakumar M, Kapgate BP, Rajkumar K (2020) Laboratory studies on strength behavior of concrete added with tire derived products. Mater Today: Proc 33:2665–2670 Vijayakumar G, Vishaliny H, Govindarajulu D (2013) Studies on glass powder as partial replacement of cement in concrete production. Int J Emerging Technol Adv Eng 3:153–158 Yang G, Chen X, Xuan W, Chen Y (2018) Dynamic compressive and splitting tensile properties of concrete containing recycled tyre rubber under high strain rates. S¯adhan¯a. 43:178 Yehia S, Emam E (2018) Experimental study on enhanced crumb rubber concrete. Int J Sci Eng Res 9:1240–1247 Youssf O, Mills JE, Hassanli R (2016) Assessment of the mechanical performance of crumb rubber concrete. Constr Build Mater 125:175–183 Youssf O, Mills JE, Benn T, Zhuge Y, Ma X, Roychand R, Gravina R (2020) Development of crumb rubber concrete for practical application in the residential construction sector—Design and processing. Constr Build Mater 260:119813 Zhang YC, Gao LL (2018) Mechanical performance test of rubber-powder modified concrete. In: E3S web of conferences, vol 38, 03006 Zheng L, Sharon Huo X, Yuan Y (2008) Experimental investigation on dynamic properties of rubberized concrete. Constr Build Mater 22:939–947 Ziolkowski P, Niedostatkiewicz M (2019) Machine learning techniques in concrete mix design. Materials 12:1256

Chapter 17

Water Quality Characteristics in the Source Areas of Yangtze River and Lancang River in Wet Season, in Tibet Plateau Min Liu, Cheng Han, Liangyuan Zhao, Huawei Huang, Yuting Zhang, Yuan Hu, Wei Deng, Shengfei Deng, and Mingli Wu

Abstract The physicochemical property of the river in the SAYR and LCJ in wet season were analyzed to reveal the water quality characteristics. The suitability evaluation of water quality in the rivers from source areas was carried out to identify whether the water quality of different rivers was suitable for irrigation. The results showed that the water quality in the SAYR and LCJ conformed to class I–II, with weakly alkaline. The EC, TDS and pH of the river water in the source areas were high, and the water hardness was above medium hardness. The water was mainly fresh water, and some areas was brackish water. The contents of IMn , NH3 -N and TN in the source of rivers were lower than those in the Yangtze River, Lancang River and other rivers of Tibet Plateau. There were no alkali hazard risk in the source areas of Yangtze River and Lancang River, but there were salinity hazard risk. The water of Dangqu River was suitable for irrigation, the water of Tuotuo River and Chumar River was not suitable for direct irrigation, and the water of Tongtian River and Lancang River should be carefully used for irrigation. Keywords Source areas · Water quality · Characteristics · Evaluation · Suitable

M. Liu · C. Han · L. Zhao (B) · H. Huang · Y. Zhang · Y. Hu · W. Deng · S. Deng · M. Wu Basin Water Environmental Research Department, Changjiang River Scientific Research Institute, Wuhan 430010, China e-mail: [email protected] Hubei Provincial Key Laboratory of River and Basin Water Resources and Ecoenvironental Sciences, Changjiang River Scientifific Research Institute, Wuhan 430010, China L. Zhao Innovation Team for Basin Water Environmental Protection and Governance of Changjiang Water Resources Commission, Wuhan 430010, China © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_17

207

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17.1 Introduction The source areas of the Yangtze River (SAYR) and Lancang River (LCJ) are over 4000 m above sea level, located in the hinterland of the Qinghai-Tibet Plateau known as the “Water Tower of China”. It was an important ecological security barrier for the country, as well as a sensitive and vulnerable area of climate change (Li et al. 2022; Zhu et al. 2019). In recent years, the global temperature rise had led to the melting of glaciers in the SAYR and LCJ, the increase of water supply in the region, the rise and expansion of the lake surface, and the change of runoff in the main rivers (Shen et al. 2009). With the development of regional tourism, the number of tourists entering the river source increased significantly (Wu et al. 2020). Under the influence of global warming and human activities, environmental problems such as snow line rise, glacier retreat, soil and water loss, desertification and grassland degradation in the SAYR and LCJ had become increasingly prominent (Zhu et al. 2019; Shen et al. 2009), the characteristics of river in the source areas also changed, mainly including water quality, hydrological process and water ecological environment. Relevant studies showed that the water quality of rivers in the SAYR was good, and the water quality index of most regions reaches the Class I-II class water quality standard. The water quality of rivers in different regions of the source area had certain differences depend on geological background (Zhao et al. 2019; Liu et al. 2021a, 2021b). Major water quality parameters in the Lancang River (Tibet section) had relatively strong temporal and spatial fluctuations. The content of major pollutants exceeding national standards, such as Total nitrogen (TN), Total phosphorus (TP) and Chemical oxygen demand (CODcr ), but they tend to get better year by year (Zhu et al. 2022). The water quality of river was very important for people’s life and social and economic development in the basin. The quality of the ecological environment in the SAYR and LCJ was related to the survival and development of local people, and also affected the sustainable development of the Yangtze River and Lancang River. Therefore, the SAYR and LCJ were taken as the object, analyzed the current situation and water environment characteristics of the region, evaluated the applicability of regional water, and provided scientific basis for the comprehensive utilization of plateau river and lake water resources and water ecological environment protection.

17.2 Materials and Methods 17.2.1 The Study Area The SAYR and LCJ located in the southwest of Qinghai Province, in the Sanjiangyuan Nature Reserve, on the Tibet Plateau with an altitude of more than 3500 m. It continuously delivered high-quality water resources to the lower reaches, making the Yangtze River had a long history. The basin area of the SAYR was 138,000 km2 , accounting

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for 44% of the total area of San Jiangyuan Nature Reserve (Shen et al. 2009). The main rivers in the source area of the Yangtze River included the Tuotuo River, the Dangqu River, the Chumar River and the Tongtian River. Lancang River originated from Zadoo County, Yushu Prefecture, Qinghai Province (Liu et al. 2021a, b). It had two river sources, the north source was Zaa Qu and the west source was Zana Qu. The main stream length of Lancang River source region was 454 km, and the drainage area was 52,900 km2 (above Changdu Hydrology Station). The main source of surface water resources in the SAYR and LCJ was glacial meltwater, rainfall and permafrost meltwater (Shen et al. 2009).

17.2.2 Samples Collection In order to understand the current water quality of the SAYR and LCJ, 17 sampling sites (see Fig. 17.1) were set up in the source areas in July 2022 (wet season) according to the river system characteristics, geographical environment characteristics and accessibility of field investigation. 13 sampling sites were set in the SAYR, and 4 sampling sites were set in the LCJ (Table 17.1). The surface sample was collected from each sampling site, and the sampling site was located 0.5 m below the water surface. The temperature (T), dissolved oxygen (DO), pH, electrical conductivity (EC) and total dissolved solids (TDS) of water were monitored by the multi-parameter water quality analyzer (Zhao et al. 2019).

Fig. 17.1 Monitoring sites in the SAYR and LCJ

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Table 17.1 The detail information of sampling sites The region

Sample ID

Sampling site

Altitude (m)

Latitude

Longitude

The source of the Yangtze River

SAYR-01

The source of Dangqu

4861

33°51' 57''

92°22' 01''

SAYR-02

The bridge of Dangqu River

4653

32°41' 28''

94°25' 30''

SAYR-03

The bridge of Dangqu

4676

32°52' 15''

94°12' 53''

SAYR-04

Yanshiping of Buqu

4525

33°35' 33''

92°03' 53''

SAYR-05

The estuary of Buqu

4525

33°51' 55''

92°22' 01''

SAYR-06

Gaerqu

4662

33°51' 55''

92°22' 01''

4483

34°13' 15''

92°26' 37'' 93°18' 20''

SAYR-07 SAYR-08

Chumar River

4479

35°18' 21''

SAYR-09

Nangjibalong

4401

34°07' 42''

93°00' 55''

4486

34°11' 10''

94°50' 39'' 95°49' 18''

SAYR-10

The source of the Langcang River

Tuotuo River

Keqianqu

SAYR-11

Nieqiaqu

4016

34°01' 25''

SAYR-12

Qumalai of Tongtian River

4024

34°01' 26''

95°49' 20''

SAYR-13

Zhimenda

3494

33°00' 45''

97°14' 17''

LCJ-01

Zhanaqu

4497

33°9' 50''

94°16' 20'' 96°37' 31''

LCJ-02

The bridge of Zhaqu

4335

32°30' 09''

LCJ-03

Zhaduo

4031

32°54' 08''

95°15' 18''

3609

32°18' 43''

96°27' 19''

LCJ-04

Nangqian

17.2.3 Sample Analysis The cations (K+ , Na+ , Ca2+ , Mg2+ ) were detected by microwave plasma atomic emission spectrometer (MP-AES) in water. The detection limit of the cations was 0.0002–0.0004 mg/L, and the recovery rate was 95.6–97.3% (Zhao et al. 2019; Liu et al. 2021a). Analysis of bicarbonate (HCO3 − ) in water by titration (Gran 1952). Total hardness (TH) was calculated by empirical formula (Raju et al. 2011). The indices of TN, ammonia nitrogen (NH3 -N), TP and permanganate (IMn ) were detected by relevant the standard methods of China (Zhao et al. 2019).

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17.3 Results and Discussion 17.3.1 Analysis of Water Quality Results The average temperature of T was 13.28 °C in the SAYR and LCJ (Table 17.2). The average value of pH was 8.42, showing a weak alkalinity. The value average value of Do was 8.16 mg/L, presenting an aerobic state. The average value of EC was 1115 µS/cm. The average value of TDS was 660 mg/L. The average value of TH was 515 mg/L. The mean content of IMn was 1.32 mg/L, the mean content of NH3 -N circumference was 0.16 mg/L, the mean content of TN was 0.46 mg/L. The mean content of TP was 0.02 mg/L. The average contents of pH, Do, IMn and TP in the source areas meet Class I water quality standards in GB3838-2002 (Safe Protection and Administration (SEPA) 2002), and The content of NH3 -N meet Class II water quality standards. Other water quality indexes had no relevant surface water standards and were not evaluated for the time being. According to the coefficient of variation (CV) criterion analysis (Guo et al. 2022), pH and Do showed low variation (CV < 0.15) (Fig. 17.2), indicating good spatial homogeneity. The value of T, TH and TP showed moderate variation (0.15 < CV < 0.36), the value of EC, TDS, IMn , NH3 -N and TN showed high variation (CV > 0.36), while the value of EC showed very high variation (CV > 1), indicating that the water quality in the SAYR and LCJ might be affected by human activities and regional geological background were significant differences (Huang et al. 2016). The pH and DO in the SAYR were slightly higher than those in the main stream of the Yangtze River, while the conductivity was about 3.5 times that of the downstream of the Yangtze River (300.9 µS/cm), and the content of NH3 -N, TN and TP were Table 17.2 The water quality in the SAYR and LCJ Area

Subjects T (°C)

SAYR Mean

DO EC (mg/ (µS/ L) cm)

TDS (mg/L)

TH IMn (mg/ NH3 -N TN TP (mg/ L) (mg/L) (mg/ (mg/ L) L) L)

13.09 8.40 8.12 1112

647

482

1.44

0.18

0.44 0.022

Min.

7.54 8.08 7.06 199

145

279

0.56

0.05

0.22 0.009

Max.

18.55 8.75 9.32 5326

2875

693

4.50

0.44

0.67 0.049

0.31 0.02 0.09 1.23

1.11

3.39 0.75

0.62

0.29 0.587

13.90 8.49 8.29 1126

702

620

0.09

0.54 0.011

CV LCJ

pH

Mean

0.92

Min.

9.77 8.38 7.61 709

423

339

0.76

0.04

0.42 0.009

Max.

17.31 8.61 8.83 2160

1281

812

1.23

0.16

0.70 0.014

0.23 0.01 0.07 0.61

0.56

CV Mean The SAYR Min. and Max. LCJ CV

13.28 8.42 8.16 1115.40 660.26 7.54 8.08 7.06 199.10

0.60

0.27 0.321

0.16

0.46 0.02

1.32

279

0.56

0.04

0.22 0.01

18.55 8.75 9.32 5325.50 2875.00 812

4.50

0.44

0.70 0.05

0.29 0.73

0.68

0.29 0.61

0.29 0.02 0.09 1.10

145.00

0.32 0.23 515

0.98

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Fig. 17.2 The value of water quality index

much lower than those in the Yangtze River (Yu et al. 2022). NH3 -N, TN and TP in the water from the LCJ were much lower than those main stream of Lancang River (Guo et al. 2022), which was mainly due to the influence of human activities on the source area of the river. Compared with other rivers of the Tibetan Plateau, the value of pH, TDS and TH in the water in the source areas were higher than that of the Yarlung Zangbo River, the content of NH3 -N and TP were much lower than that of the Yarlung Zangbo River (Wu 2022), and the content of IMn , NH3 -N and TP were slightly lower than the headwater of the Yellow River (Shi et al. 2012).

17.3.2 The Characteristics of Water Quality Characteristics (1) Analysis of conventional physical and chemical indexes The TH in the SAYR and LCJ reached above medium hardness and was mainly fresh water (Fig. 17.3). However, the LCJ-01 were brackish water, which was mainly related to the geological background. The value of TH in the Tuotuo River water from the SAYR was lower than that in 2018, while TH in the Dangqu was much higher than that in 2018 (Zhao et al. 2019), indicating that there were certain differences in physicochemical property of different rivers in the source areas. This might be due to the influence of complex topography and changeable local climate (Liu et al. 2021b). The TH of the main stream water in the LCJ gradually decreased from the upper stream to the lower stream, which might be caused by the dilution of other low-hardness tributaries in the lower stream.

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Fig. 17.3 The distribution of total soluble solids and hardness in the study area

(2) Analysis characteristics of water quality The content of IMn and NH3 -N in the SAYR were higher than those in the Lancang River on the whole (Fig. 17.4). The fluctuation of IMn and NH3 -N in the Dangqu (SAYR-01 ~ SAYR-03) might be due to the frequent grazing activities along the Dangqu and the direct discharge of cattle and sheep excrement into the water body. The content of NH3 -N in the Tuotuo River (SAYR-08) was higher than others. The main reason was that the sampling site located in Tanggulashan Town, which was greatly affected by the activities of urban residents. The content of NH3 -N in Tongtian River (SAYR-09 ~ SAYR-13) decreased from upstream to downstream. And TP < 0.1 mg/L. The content of TN in the Tongtian River and Lancang River (LCJ-01 ~ LCJ-04) were higher than others. The content of TN and TP fluctuated less in the main stream of Dangqu.

17.3.3 Evaluation of Water Quality Suitability (1) Salinity hazard and alkali hazard Excessive sodium and salinity concentrations in irrigation water could lead to sodium hazards and salinity hazards (Raju et al. 2011). The sodium in the water replaced the calcium and magnesium in the soil, reducing the phosphorus content and permeability and hardening the soil. Parameters such as sodium (Na%), sodium adsorption ratio (SAR) and electrical conductivity could be calculated according to this method to evaluate the quality of irrigation water (Raju et al. 2011). The range of sodium adsorption ratio in the Yangtze River and Lancang River was 0.25–14.69, with an average value of 2.43, indicating that there was no alkali hazard risk (SAR < 18).

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Fig. 17.4 The distribution characteristics of water quality

The value of EC ranged from 199 to 5326 µS/cm, with an average value of 1115 µS/ cm, indicating that the salinity in the Yangtze River and Lancang River regions was relatively high on the whole, and the salinity hazard risk (EC > 750 µS/cm) exists in most of the sampling sites. The sampling points of Dangqu fall in C1S1 and C2S1 (Fig. 17.5), it indicated that Danqu was mainly low-sodium medium-salt water, which meet the requirements of irrigation water quality. The sampling site of Tuotuo River and Chumar River located at C3S2, and the SAR values were all greater than 10, indicating that the Tuotuo River and Chumar River were not suitable for direct irrigation. The sampling sites of Tongtian River and Lancang River mainly located at C3S1, indicating that water could be used for irrigation, but in order to reduce the risk of salinization, it was recommended to be used for irrigation of salt-tolerant plants. According to the value of Na%, irrigation water was divided into five categories: Na% < 20, the water was very good; 20 < Na% < 40, the water was better; 40 < Na% < 60, the water could generally be used for irrigation; 60 < Na% < 80, the water might not be suitable for irrigation; Na% > 80 (Liu et al. 2021a, 2021b), the water could not be directly used for irrigation. The value of Na% ranged from 5.4 to 73.7 in the SAYR and LCJ, with an average value of 24.8, which showed the water quality was good, but there were great differences among different rivers. The values of Na% were less than 40 in the water of Dangqu, Niqiaqu, Keqiqu and Lancang River, indicating that the water of the above rivers were suitable for irrigation. Except for Dangqu, the values of Na% in the SAYR were above 40, indicating that the water of these rivers should be carefully used for irrigation. (2) The permeability index According to the permeability index (PI), the influence of water on soil permeability in irrigated areas could be assessed. If the water PI > 70%, it would not affect the permeability of irrigated soil; if the PI < 25%, it would affect the permeability of

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Fig. 17.5 Diagram for irrigation waters classification in the study area

irrigated soil (Raju et al. 2011). It could be seen from the calculation that the value of PI in the SAYR and LCJ was 15.1–76.5%, with an average value of 35.7%. About 11.8% of the sampling points had no effect on soil permeability (PI < 25%), and 88.2% of the sampling points had some effect on soil permeability.

17.4 Conclusion The water in the SAYR and LCJ generally conforms to class I–II water quality, and the water was weakly alkaline. the river water in the SAYR and LCJ were above medium hardness and were mainly fresh water. EC, TDS, IMn , NH3 -N and TN in the SAYR and LCJ differ greatly in different regions in wet season. The water quality suitability evaluation results that there were no alkali hazard risk,but there were salinity hazard risk in the Tuotuo River and Chumar River were not suitable for direct irrigation, and the other rivers should be carefully used for irrigation. Acknowledgements This study was supported by the Central Public-interest Scientific institution Basal Research Fund of China (Grant No. CKSF2023191/SH, CKSF2023311/SH, CKSF2023337/ SH).

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References Gran G (1952) Determination of the equivalence point in potentiometric titrations, Part II. Analyst 77:661–671 Guo S, Chen A, Xi B, Ju X, Huang H, Liu J, Mao Y, Guo Y, Lei B (2022) Analysis of nitrogen and phosphorus pollution and nitrogen sources in the Lancang River. Environ Sci 43(12):5491–5498 Huang Z, Liu Y, Zhao W, Zhao L (2016) Discussion on recent spatial-temporal distribution of water quality in Yangtze River source area. J Yangtze River Sci Res Inst 33(07):46–50+67 Li H, Zhao W, Zhao L, Li W, Cao X (2022) Distribution of the summer phytoplankton community in source regions of the Yangtze River and Lancang River. J Hydroecol 43(3):77–85 Liu M, Zhao L, Li Q, Zou J, Hu Y, Zhang Y, Xu P, Wu Z, Deng W, Tao J (2021a) Hydrochemical characteristics, main ion sources of main rivers in the source area of Yangtze River. China Environ Sci 41(3):1243–1254 Liu M, Zhao L, Li Q, Hu Y, Huang H, Zou J, Gao F, Zhang Y, Xu P, Wu Z (2021b) Disribution characteristics, enrichment patterns and health risk assessment of dissolved trace elements in river water in the source area of the Yangtze River. J Water Clim Change 12(6):2288–2298 Safe Environmental Protection Administration (SEPA) (2002) Environmental quality standard of surface water: GB3838-2002. China Environmental Press, Beijing Raju N, Shukla U, Ram P (2011) Hydrogeochemistry for the assessment of groundwater quality in Varanasi: a fast-urbanizing center in Uttar Pradesh, India. Environ Monit Assess 173(1–4):279– 300 Shang F, Wang K, Huang Y, Wei J (2020) Variation characteristics of runoff and the quantitative separation based on Budyko hypothesis in the there-river headwaters region. J Tongji Univ (nat Sci) 48(2):305–316 Shen Y, Wang G, Wang G, Pu J, Wang X (2009) Impacts of climate change on glacial water resources and hydrological cycles in the Yangtze River source region, the Qinghai-Tibetan Plateau, China: A Progress Report. Sci Cold Arid Regions 1(6):0475–0495 Shi L, Zhao X, Ni T, Yang Y, Dou X, Han D, Bai Z (2012) Quality of surface water in Yellow River headwater area of the origin of Three Rivers in Qinghai Province. Guizhou Agric Sci 40(04):220–223 Wu C (2022) The relationship between the community structure of zooplankton and environmental factors in the Yarlung Zangbo River and its main tributaries. Wuhan Polytechnic University, Wuhan Wu Z, Xu P, Zhao L, Yuan Z, Yan X, Ren F, Li W, Xu J, Wu Q, Liu M (2020) Comprehensive scientific investigation report of the source area of the Yangtze River (2019). Changjiang Press, Wuhan Yu Y, Wang D, Tang X, Li R (2022) Transport characteristics of main nutrients and contribution of tributaries in middle and lower reaches of Yangtze River at end of flood season. Resour Environ Yangtze Basin 31(05):1039–1050 Zhao L, Li W, Lin L, Guo W, Zhao W, Tang X, Gong D, Li Q, Xu P (2019) Field investigation on river hydrochemical characteristics and larval and juvenile fish in the source area of the Yangtze River. Water 11(7):1–20 Zhou S, Zhou Y, Yan X, Fan B (2019) Sediment distribution on Nangqian Reach in the source area of Lancang River. J Sediment Res 44(6):46–52 Zhu L, Ju J, Qiao B, Yang R, Liu C, Han B (2019) Recent lake changes of the Asia Water Tower and their climate response: progress, problems and prospects. Chin Sci Bull 64:2796–2806 Zhu T, Du H, Hu X, Hu F, Gong J, Li X (2022) Evaluation and water quality influencing factors of the Tibet reach of the Lancang River based on the water quality index. Freshwater Fisheries 52(5):104–111

Chapter 18

Energy Consumption and Carbon Emission of Residential Areas in Changsha Based on Local Climate Zone Scheme Yaping Chen, Hui Ding, Yinze Hu, and Yanyun Feng

Abstract In response to the issues of significant growth in energy consumption and continuous increase in carbon emissions in residential buildings due to the global warming and rapid urbanization, a method combining local climate zone (LCZ) scheme, bottom-up physical modelling, and DeST-h numerical simulation has been adopted to analyze the spatial distribution characteristics of local climate zones (LCZ), as well as the energy consumption and carbon emissions of residential buildings of Changsha. The results indicate that the annual cumulative carbon emissions per unit area of open residential buildings in Changsha are: LCZ-6 > LCZ-5 > LCZ-4. LCZ-4 has the lowest annual cumulative carbon emissions per unit (28.19 kg CO2 m−2 a−1 ). The annual cumulative carbon emissions per square kilometer of residential buildings in Changsha are LCZ-4 > LCZ-5 > LCZ-6. The carbon emission distribution map of residential buildings generated in the study help contribute to theoretical guidance for the low-carbon development of Changsha. Keywords Energy consumption · Carbon emission · Local climate zone

18.1 Introduction Climate change is a global issue that affects the fate of the human race as a community, and it is a major challenge faced by sustainable development of mankind in the twenty-first century. The construction industry, as one of the three major areas of Y. Chen · H. Ding (B) School of Design and Art, Hunan University of Technology and Business, Changsha, China e-mail: [email protected] Y. Hu Hunan Lugu Architectural Technology Co., Ltd., Changsha, China Y. Feng Hunan Agricultural University, Changsha, China © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_18

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energy consumption, accounts for a large amount of carbon emissions. Carbon emissions from building operations mainly come from energy consumption, including air conditioning systems, lighting systems, power equipment systems, domestic hot water, gas systems and so on. According to the International Energy Agency (IEA), building operations accounted for 30% of global energy consumption and 28% of carbon emissions, while building operation carbon emissions accounted for 22% of the total carbon emissions of China in 2019 (IEA 2023). Therefore, reducing the carbon emissions intensity of building operation stage is a necessary task to address global climate change and achieve the goal of “carbon peak and carbon neutrality.” Carbon emissions caused by building energy consumption have gradually become the main source of carbon emissions from construction land. Building energy consumption not only characterizes the important form of carbon emissions, but also is an important evaluation index of the low-carbon development level of cities. Exploring the relationship between built environment, building energy consumption and carbon emissions from construction land will help compare carbon emissions levels of cities under different built environment scenarios and provide a basis for the construction of low-carbon cities in China. Many scholars have conducted research on energy consumption and carbon emissions in the construction industry. Hu (2020) defined and classified energy consumption and carbon emissions in construction industry of China and established the China Building Energy Consumption and Emissions Model (CBEEM). The research used field investigation data and statistical analysis data to calculate the energy consumption and carbon emissions during the construction and operation stages of existing buildings and put forward specific suggestions for achieving energy-saving and lowcarbon development in the construction industry (Hu et al. 2020). Duan et al. (2020) applied DeST-h energy consumption simulation software to analyze the impact of indoor and outdoor ventilation and heat transfer coefficients of building envelope on the cold and heat load of residential buildings. The results show that the indoor ventilation frequency has a greater impact on the cold load of residential buildings, while a relatively small impact on the heat load of residential buildings (Duan et al. 2020). Ran proposed a new integrated model (stacking model) for building energy consumption prediction, which can be used to predict building energy consumption from different spatial and structural perspectives (Ran et al. 2020). Long and Liang (2021) measured the operating carbon emissions and embodied carbon emissions of buildings, pointing out that the main factors affecting the carbon peak of urban buildings are the construction scale and service life of buildings (Long and Liang 2021). Liu et al. (2021) proposed a DeST-urban simulation platform to automatically complete DeST energy consumption models of urban buildings and achieve the goal of quantitatively analyzing urban energy consumption using 3D urban geometric data models (Liu et al. 2021). Han and Liu (2021) used DeST software to conduct low-energy simulation of residential buildings in cold areas. The results showed that improving the thickness of external wall insulation was very important for residential energy-saving efforts. The window-to-wall ratio should be minimized and the heat transfer coefficient of building roof should be strictly controlled (Han and Liu 2021). However, existing studies lack a summary of energy consumption and carbon

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Fig. 18.1 The study area of Changsha

emissions regarding to different urban spatial forms. Therefore, the study analyzed the spatial distribution characteristics of local climate zones, and calculated the data of energy consumption and carbon emissions of residential areas in Changsha, the results of which would contribute to establishing a low-carbon and energy-saving city.

18.2 Methodology 18.2.1 Study Area Changsha is the capital city of Hunan Province. It is an important central city in the middle reaches of the Yangtze River and the central city of the Chang-Zhu-Tan Urban Agglomeration. It is located in the hot summer and cold winter regions of China, with the summer hot and humid, while the winter cold and wet (Fig. 18.1).

18.2.2 LCZ Mapping The study applied the WUDAPT algorithm to generate the LCZ map of Changsha. Firstly, vectorized map data was imported into the SAGAGIS platform. Secondly,

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the Google Earth platform was used to digitize the LCZ polygons of the representative training areas. Each type of local climate zone was represented by a polygon sample of the training area. To facilitate automatic classification, 20–30 training area samples were required for each LCZ. Thirdly, each training area sample was selected through Google Earth to ensure that it was no smaller than 1km2 and that its shortest side was no smaller than 200 m. The range of the training area was ensured to be representative of all directions and types. Four aspects and corresponding 10 indicators of the representative training area were classified in the SAGAGIS platform, including urban form, land cover, building materials and human activities (Stewart and Oke 2012). The pre-processed 100 * 100-pixel rasterized image SGRD file and the selected training area samples in Google Earth were loaded into the SAGAGIS platform. Fourthly, the similarity between the training area samples and the remaining study area was used to classify the study area using the supervised classification random forest algorithm. The map results were verified by comparing with the training areas. Any areas that were not identified were resampled to redefine the training areas until the recognition rate met the specified requirements. Finally, export the KML file from SAGAGIS and load it into Google Earth to continuously zoom in and verify the actual area types.

18.2.3 Energy Consumption Models The study applied the Designer’s Simulation Toolkits (DeST), a building thermal environment design simulation software developed and applied by Tsinghua University, to simulate the annual hourly load and energy consumption of buildings. Firstly, the study models the residential buildings in three typical local climate zones (LCZ-46) based on the LCZ map of Changsha. The study sets up residential building models according to the average results of field research in residential areas in Changsha (Fig. 18.2; Table 18.1). The average value of various residential buildings is taken for the parameters such as the floor height of three typical residential buildings, the thermal performance heat transfer coefficient of the envelope, the building shape coefficient and the window wall area ratio. The thermal performance heat transfer coefficient of the envelope of residential buildings in Changsha City (Table 18.2) and the thermal disturbance

LCZ-4 Fig. 18.2 The spatial form of LCZ-4-6

LCZ-5

LCZ-6

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Table 18.1 Residential building model setting Type

Floor

Floor height (m)

Area (m2 )

Total building area (m2 )

LCZ-4

16

3

600

9600

LCZ-5

8

3

600

4800

LCZ-6

3

3

200

600

Table 18.2 Thermal performance and heat transfer coefficient of envelope structure of residential buildings in Changsha Type

Roofing

Exterior wall

Floor

Window

Exterior ground

LCZ-4

0.2

0.4

0.4

1.6

0.6

LCZ-5

0.2

0.35

0.35

1.6

0.6

LCZ-6

0.2

0.3

0/3

1.6

0.6

Table 18.3 Setting of indoor thermal disturbance parameters of residential buildings in Changsha

No.

Type

Data

1

Equipment power density

10 Wm−2

2

Lighting power dens

5.0 Wm−2

3

Indoor ventilation frequency

0.2–0.5 h−1

4

Air conditioning system operating time

0:00–24:00

parameters such as the form, equipment density and lighting density of the indoor air conditioning system in residential buildings (Table 18.3) are set according to the Code for Design of Energy Efficiency of Residential Buildings in Hot Summer and Cold Winter Regions (JGJ134-2021), Code for Design of Heating, Ventilation and Air Conditioning of Civil Buildings (GB50736-2012), and Code for Thermal Design of Civil Buildings (GB50176-2016). Secondly, input hourly meteorological data of typical years in Changsha. The study uses typical annual meteorological data from Changsha City, and sets the starting time for air conditioning heating in winter from November 1st to the end of the heating season on March 1st, with an indoor temperature of 20°C and a relative humidity of 30%. The summer air conditioning season starts from June 1st and ends on September 1st, with an indoor temperature of 26°C and a relative humidity of 60%.

18.2.4 Carbon Emission Models According to the “Annual Development Research Report on Building Energy Efficiency in China 2021” (Stewart and Oke 2012), the average electric carbon emission factor in Changsha is 0.5 kg CO2 kW−1 h−1 . Therefore, the calculation formula for carbon emissions of Changsha is as follows:

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CE = θ ∗ EC

(18.1)

where, CE means carbon emission value, kgCO2 ; θ represent average carbon emission factor of electricity in Changsha, CO2 kW−1 h−1 , EC means energy-consumption value, kW−1 h−1 .

18.3 Results 18.3.1 LCZ Map of Changsha According to the map of local climate zones in Changsha (Fig. 18.3) and the proportion of built-up LCZs (Table 18.4). The three most common types were LCZ-4, LCZ5 and LCZ-6. Open low-rise buildings (LCZ-5) accounted for 21.48%, followed by open high-rise buildings (LCZ-4) accounting for 8.26% and LCZ-6 (1.53%). These LCZ types were distributed sporadically in clusters of residential areas and the open low-rise building forms were rare, indicating that in thriving development of construction industry of Changsha recently. Although compact high-rise buildings (LCZ-1) and compact mid-rise buildings (LCZ-2) took up only a small proportion in Changsha, at 0.34% and 0.49% respectively, they were highly prevalent in highly urbanized central areas. Compact high-rise LCZs were mainly concentrated in eastern river, while open high-rise buildings (LCZ-4) was concentrated in southern district. Compact low-rise buildings (LCZ-3) accounted for 0.71% in Changsha and were distributed in central old communities and heritage conservation areas.

18.3.2 Distribution Characteristics of Energy Consumption in Open LCZ Areas As Figs. 18.4 and 18.5 shows, the annual cumulative energy consumption of cooling per unit area of buildings in summer is far greater than the annual cumulative energy consumption of winter heating. The annual cumulative energy consumption per unit area of open residential buildings in Changsha is LCZ-6 > LCZ-5 > LCZ-4. The cumulative annual energy consumption per unit area of LCZ-6 is 37.54 kW hm−2 a−1 . The cumulative annual energy consumption value for heating per unit area of LCZ-4 building is 34.31 kW hm−2 a−1 . The annual cumulative energy consumption per unit area of residential buildings calculated by verifying DeST-h simulation meets the content of “Energy Efficiency Design Standard for Residential Buildings in Hunan Province” (DBJ 43/001). LCZ6 has the highest annual cumulative energy consumption value for heating per unit area (15.84 kW hm−2 a−1 ), while LCZ-4 has the lowest annual cumulative energy consumption value for heating for open low rise single building residential buildings

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Fig. 18.3 The LCZ map of Changsha

Table 18.4 The percentage of built-up LCZs in Changsha LCZ

Type Built-up

Compact

Open

Proportion (%)

1

0.34

2

0.49

3

0.71

4

8.26

5

21.48

6

1.53

Total 32.81%

in Changsha (15.38 kW hm−2 a−1 ). LCZ-4 features the highest annual cumulative energy consumption value (127.49 kW hm−2 a−1 ), while LCZ-3 characterized the minimum annual cumulative energy consumption (7.01 kW hm−2 a−1 ). The minimum annual cumulative total energy consumption of a single residential building in LCZ-6 is 24.83 MW/h. The annual cumulative total energy consumption of a single residential building in Changsha city is LCZ-4 > LCZ-5 > LCZ-6. The highest cumulative annual total energy consumption of LCZ-5 buildings is 5,733,688 MW h, while the lowest cumulative total energy consumption of LCZ-4 buildings is 812321

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Fig. 18.4 The energy consumption of heating and cooling per unit of LCZ-4–6

Fig. 18.5 Annual cumulative energy consumption per unit area of LCZ-4–6

MW h. The annual cumulative total energy consumption of residential buildings in the research area of Changsha City is LCZ-5 > LCZ-6 > LCZ 4.

18.3.3 Distribution Characteristics of Carbon Emissions in Open LCZ Areas The average carbon emissions per unit area of LCZ-4–6 residential buildings are 28.01 kW hm−2 a−1 , which is in line with the average carbon emissions during the operation stage of Chinese heating urban residential buildings in the “2021 Annual Development Report on Building Energy Efficiency in China” (Tsinghua University Building Energy Efficiency Research Center 2021). The annual cumulative carbon emissions per unit area of open residential buildings in Changsha city are: LCZ-6 > LCZ-5 > LCZ-4. LCZ-4 has the lowest annual cumulative carbon emissions per

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Fig. 18.6 The carbon emission map of LCZ-4, LCZ-5 and LCZ-6

unit (28.19 kg CO2 m−2 a−1 ). The annual cumulative carbon emissions per square kilometer of residential buildings in Changsha are LCZ-4 > LCZ-5 > LCZ-6. The LCZ-6 building features the lowest annual cumulative carbon emissions (13,972 tCO2 ). As shown in Fig. 18.6, it can be seen from the annual cumulative carbon emissions distribution map of residential buildings per square kilometer in Changsha that high carbon emission areas are mainly distributed in eastern river and should be the primary area for reducing carbon emissions from residential buildings, especially the central urban area.

18.4 Discussion The study simulates energy consumption and carbon emissions of LCZ-4–6 at the regional scale in Changsha. The areas with high carbon emissions are concentrated within the Second Ring Road, consisting largely of LCZ-4 and LCZ-5. The reason for the high carbon emissions in summer may be due to the extremely high heat island intensity trend in the city center. In the future, it is necessary to increase the green space area and strengthen outdoor ventilation, and try to use urban natural ventilation to take away indoor residual heat. Reduce indoor heat loss in winter, such as strengthening the thermal insulation performance of external walls, reducing the Heat transfer coefficient of external windows, and emission reduction measures. For old residential areas, maintenance and external wall insulation schemes should be adopted and

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avoid large-scale demolition and construction. For new buildings, carbon reduction measures such as applying green building materials should be taken. Increase the number of green buildings and organically combine them with low-carbon buildings, ultimately achieving sustainable urban development. Further research will be conducted on other types of LCZ, including rural residential buildings, public buildings and industrial factory buildings. Also, the total carbon emissions in each stage of the entire life cycle of buildings should be paid attention, such as the operation stage and demolition stage of buildings.

18.5 Conclusion By studying and constructing a LCZ map of Changsha, we found the top three LCZ types are LCZ-5 (21.48%), LCZ-4 (8.26%) and LCZ-6 (1.53%). Therefore, we have generated an annual cumulative energy consumption distribution map and carbon emission distribution map for each square kilometer of LCZ-4-6. The results show that the highest cumulative annual total energy consumption of residential buildings (LCZ-5) is 5371598 MW h, and the carbon emission value is 2,685,799 tCO2 . High carbon emission areas are mainly distributed within the Second Ring Road of eastern river and should be the primary area for reducing carbon emissions from residential buildings. The carbon emission distribution map of residential buildings generated in the study help contribute to theoretical guidance for the low-carbon development of Changsha. Foundation The study was supported by the Natural Science Foundation of Hunan Province (2023JJ40228), the Excellent Youth Foundation of Hunan Educational Committee (22B0628), the Hunan Provincial Social Science Achievement Evaluation Committee (XSP2023YSC061), the Natural Science Foundation of Changsha (kq2208058), the Teaching Reform Research Project of Hunan University of Technology and Business (7103411CYP01).

References Duan L, Wang Z, Bu H (2020) Research on residential building load simulation based on DeST. J Liberal Arts College (nat Sci Edn) 32(01):74–78 Han X, Liu N (2021) DeST simulation of low energy residential buildings in high cold regions. Comput Simul 38(02):169–173 Hu S, Zhang Y, Yan D (2020) Definition and accounting of energy consumption and carbon emissions in China’s construction industry. Build Sci 36(02):288–297 IEA. International energy agency. www.iea.org. Accessed 3 Jan 2023 Liu Z, Yan D, Wu R (2021) Development of DeST urban building energy consumption simulation platform. Architect Sci 37(10):16–23

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Long W, Liang H (2021) Discussion on carbon peak and carbon neutrality path of urban buildings in China. HVAC 51(04):1–17 Ran W, Lei LS, Wei F (2020) A novel improved model for building energy consumption prediction based on model integration. Appl Energy 262(07):188199 Stewart ID, Oke TR (2012) Local climate zones for urban temperature studies. Bull Am Meteor Soc 93(12):1879–1900 Tsinghua University Building Energy Efficiency Research Center (2021) Annual development research report on building energy efficiency in China 2021. China Architecture & Building Press

Chapter 19

Study on the Regulation in Countering the Impacts of Climate Change on Water Resource Junming Gong, Wei Wu, and Chenyu Lin

Abstract This paper focuses on the issues of regulations involved in countering the impacts of climate change on water resources, enumerates specific impacts of climate change on water resources, explores existing regulations, and proposes multi-actor cooperation as an optimization of the existing regulatory system on climate change and water resources, which also serves as a reference for regional States and the international community. Specifically, this paper first enumerates the impacts caused by climate change on water resources, namely the supply, quality, and transboundary conflicts regarding water resources. Secondly, we illustrate and review the current regulations in dealing with the impacts of climate change on water resources from the perspective of international law and domestic legislation. Finally, the article takes international cooperation as the principal approach and proposes multi-actor participation and collaboration on both public and private levels, emphasizing the specific measures for different actors and the function of public power, private sectors, and individual citizens. Keywords Climate change · Water resources · International law · Domestic legislation

19.1 Introduction Water resources are vital to life on Earth. They support many ecosystems and provide habitat and breeding grounds for animals and plants. Many industries, such as agriculture and energy production, also depend on adequate water resources. Animals, plants, and humans all need water to survive.

J. Gong · W. Wu (B) China Institute of Boundary and Ocean Studies, Wuhan University, Wuhan City 430072, China e-mail: [email protected] C. Lin Law School, Ocean University of China, Qingdao City 266100, China © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_19

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In the context of climate change, which is mainly characterized by global warming, countries around the world are facing extremely serious climate and ecological problems: extreme weather events are frequent, the number of natural disasters is on the rise, and meteorological disasters are particularly prominent. To address this situation, this paper first illustrates the impacts of climate change on water resources from the perspectives of water resources supply, water resources quality, and transboundary water resources conflicts. Second, we review the existing national laws and international legal regulatory measures. Finally, this paper proposes solutions at the public level, private level, and multi-actor cooperation level for betterunified responses to climate change and water resources management.

19.2 Impacts of Climate Change on Water Resources Water is an important factor in the climate system. At the same time, climate change also has many impacts on water resources. Specifically, the main impacts are in the aspects of water supply, water quality, and transboundary water conflicts.

19.2.1 Impact on the Supply of Water Resources Climate change can have impacts on water availability in specific regions, and these impacts vary from region to region. In some areas, rising temperatures, droughts, and reduced snowfall will reduce water availability (Lall et al. 2018). In arid regions, most of the daily water supply comes from groundwater in aquifers (Wu et al. 2020). Increased temperatures due to climate change may accelerate water evaporation and increase people’s water demand. As a result, the inhabitants will extract more groundwater from the aquifer thereby increasing the drought level in the region. Intensified drought and resulting wildfires can destroy surface vegetation, increase soil erosion, and further reduce groundwater refill. In other regions, extreme weather such as heavy rains and floods can dramatically increase water availability in a short period of time. Warmer air can hold more moisture than cooler air. As a result, warmer climates will draw more water from the oceans, lakes, soil, and plants. The excess moisture present in the weather system will contribute to more extreme weather events such as heavy rains and floods (Caretta et al. 2022). Greater bursts of precipitation caused by warmer and more humid air could lead to flooding (The World Bank Floods and Droughts: An EPIC Response to These Hazards in the Era of Climate Change 2023), which can endanger people’s lives and property.

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19.2.2 Impact on the Quality of Water Resources Climate change can harm the quality of water resources. Increased rainfall can lead to more sediment, nutrients, pathogens, and other materials flowing into water bodies (Coffey et al. 2018). The increase in sediment will make the water turbid. The increase in nutrients, combined with the increase in temperature due to climate change, can result in harmful algal blooms in water bodies. These algae can negatively affect aquatic animals and the people who depend on the water for their survival. Sea level rise and increased drought due to climate change can salinize freshwater in estuaries, wetlands, and aquifers, and consequently harm aquatic plants and animals and reduce freshwater supplies.

19.2.3 Transboundary Water Conflict As the planet’s available freshwater resources become further scarce, more conflicts will arise among between countries over shared water sources. The main risk remains the conflict of interest between upstream and downstream countries over the allocation of water resources and flows. If one country controls a shared water source, it could lead to a massive drought in another country or other countries. For example, since the 1970s, Turkey has been gradually building dams on the Tigris and Euphrates rivers (Bilgen 2018), reducing the flow of water to Syria by 40% (MacQuarrie 2004), and rendering some of Syria’s water projects useless for a time. With the Tigris– Euphrates river system’s runoff reduced by climate change (Mueller et al. 2021), the existing water allocation problems between Turkey and Syria have been further exacerbated. In addition, there have been conflicts between Iran and Afghanistan over the allocation of water resources in the Helmand River. Iran attributes the decrease to Afghanistan’s failure to release enough water, claiming to have received only 4 percent of the water provided for in the 1973 Helmand River Treaty (Iran and Afghanistan face off over sharing Helmand waters 2023). Climate change has decreased the water level of the Helmand River (United Nations Office for Disaster Risk Reduction Water politics heat up under worsening climate in Afghanistan 2023), thereby intensifying the conflicts between the two states. Meanwhile, two state groups, Egypt and Sudan, and Ethiopia and Uganda, are much in conflict over the distribution of Nile water resources (United Nations Egypt, Ethiopia, Sudan Should Negotiate Mutually Beneficial Agreement over Management of Nile Waters, Top Official Tells Security Council 2023). Several negotiations were held to resolve the conflict between these two groups, but no new agreement on the allocation of Nile water resources was reached. As illustrated above, climate change has an impact on water availability, leading to a decrease in water resources in some areas and a sudden increase in others. Pollutants and nutrients generated by climate change can degrade water quality. Also, climate

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change will exacerbate international conflicts over the uneven distribution of water resources.

19.3 Existing Regulatory Measures The growing negative impact of climate change on water resources is damaging the social stability and national security of countries around the world. In response, countries have adopted a series of regulatory measures. Specifically, states have used both international law and domestic legislation to adapt, mitigate, or address the climate change they face and the water resources dilemmas it causes.

19.3.1 International Law United Nations Framework Convention on Climate Change (UNFCCC) was formally adopted at the Rio Earth Summit in 1992. It came into force in 1994. The UNFCCC adopts protocols to achieve the objectives of the Convention and establishes the important principle of “common but differentiated responsibilities” for international cooperation. The Paris Agreement, which was ratified soon thereafter, was designed to hold the rise in global average temperature to well below 2 °C above pre-industrial levels and to work towards limiting temperature increases to 1.5 °C above preindustrial levels (United Nations Climate Change 2023). Although the UNFCCC and the Paris Agreement themselves do not directly address water resources management, water resources are an important component of climate change mitigation and adaptation strategies. In addition, the principle of “common but differentiated responsibilities” in the UNFCCC is a guiding principle for future international cooperation on water resources. In 2015, the Sendai Framework for Disaster Risk Reduction 2015–2030 was adopted by the United Nations. This document is not legally binding. However, the Framework establishes seven global goals and four priority actions for disaster risk reduction and provides guidance for countries to reduce natural hazards alone or together. Although water is seldom mentioned in the Sendai Framework, it is reflected in every goal and action. Natural disasters related to water resources surged in the past 50 years (International Monetary Fund Dealing with Increased Risk of Natural Disasters 2023). Addressing the corresponding water issues is critical for natural disaster mitigation. Convention on the Law of the Non-Navigational Uses of International Watercourses and the Convention on the Protection and Use of Transboundary Watercourses and International Lakes, as the two fundamental treaties in the international water law, provide a framework for addressing the impacts of climate change on water resources. Many provisions of international water law support climate change adaptation measures, such as the principle of equitable and reasonable use and the

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precautionary principle (United Nations Economic Commissi FAQs 2023). While the current international water conventions do not explicitly mention climate, considering the close linkage between water resources and climate change, the current international water conventions could indirectly affect climate change. As for regional water conventions, the Mekong River Commission and the collaboration between the United States and Canada in the Great Lakes region are exemplary precedents. In 1995, Cambodia, Laos, Thailand, and Vietnam signed the Agreement on the Cooperation for the Sustainable Development of the Mekong River Basin, which established the Mekong River Commission with the aim of promoting sustainable water resource management in the region. In 1909, the U.S. and Canadian governments signed the Boundary Waters Treaty, which established the International Joint Commission to deal with transboundary water transportation issues affecting Canada and the United States. Water is an important medium to support the implementation of global agreements. Although numerous international treaties deal directly or indirectly with the management of water resources, there is still a lack of uniform international legal regulation of water resources. The existing international water conventions are more concerned with the use of water resources for navigation and do not systematically protect the water resources themselves. At the same time, the existing international climate conventions focus more on addressing climate change but do not integrate climate change and water resources management for unified regulation. Although some countries have ratified or signed relevant treaties, non-compliance and noncooperation remain. It could be seen that, although there are some international treaties regulating climate change and water resources management, the scope of the relevant treaties is still too narrow and the provisions are not uniform.

19.3.2 Domestic Legislation The United States attaches great importance to the construction of water laws and regulations. The federal government and state governments have formulated relatively sound water-related laws, regulations and policies, in which a water resources management system was organized. Although the United States does not have a unified national water law, there is a water resources management system that is compatible with the market economy system (United States Environmental Protection Agency Water Management at EPA). The legislation follows a parallel model of multiple independent laws that collectively regulate the conservation and use of water resources. Specifically, the relevant laws and regulations include the Clean Water Act, the Water Resources Planning Act, the Water Resources Development Act, the Soil and Water Conservation Act and the Safe Drinking Water Act (Justia United States Law 2023). The management system and institutions are mainly regulated through laws and regulations or governmental authorization.

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Singapore, as a small coastal country with a lack of water resources, attaches great importance to the development of laws and regulations related to water conservation. It has enacted and implemented a series of water-related laws and regulations. Specifically, these laws and regulations include the Water Pollution Management and Drainage Act, the Sewerage and Drainage Systems Act, the Public Utilities (Water Supply) Regulations, the Public Utilities (Central Catchment Areas and Catchment Parks) Regulations, and the Environmental Public Health (Public Cleansing) Regulations (Singapore Ministry of Law Homepage 2023). Israel, located in the Middle East, has been facing the threat of severe water scarcity. In response to this threat, Israel has established its water resources authority, which focuses on water conservation and water resources management (Knesset 2023). Multiple legislations regarding the management of different water resources are also implemented. Israel’s water conservation system adopts a hybrid water conservation legislation model, highlighting problem-oriented and demandoriented solutions. In other words, a comprehensive water resources law is enacted first, and then various individual regulations related to water conservation and water resources management are gradually enacted and improved according to the needs of economic and social development and management practices. China, at the policy level, officially released the China National Program to Address Climate Change in 2007 (Council and on the issuance of China’s national program to address climate change 2023). The latest white paper “China’s Policies and Actions to Address Climate Change” in 2021 emphasizes vigorously on promoting carbon peaking and carbon neutrality and giving full play to the role of market mechanisms and enhancing the capacity to adapt to climate change. It also mentions urban water body treatment and water source protection (The National People’s Congress of the People’s Republic of China China’s Policies and Actions to Address Climate Change 2023). The Environmental Protection Law of the People’s Republic of China protects water resources in general terms as part of the natural environment (The National People’s Congress of the People’s Republic of China Environmental Protection Law of the People’s Republic of China 2023). The Water Law of the People’s Republic of China aims at the rational use and protection of water resources and affirms the state-owned nature of water resources. It also provides detailed regulations on six aspects: water resources planning; water resources development and utilization; protection of water resources and water projects; water resources allocation and conservation; water disputes handling and law enforcement supervision; and legal responsibilities (The National People’s Congress of the People’s Republic of China Water Law of the People’s Republic of China 2023). In summary, the domestic legislations of many countries all provide measures for water resources management. These measures, which are based on domestic law, also influence the attitudes of countries in the development of international law and have an important role in promoting international cooperation.

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19.4 Optimization of the Current Regulatory Measures: Multi-Actor Participation and Collaboration The international community and individual countries are currently falling short in regulating the impacts of climate change on water resources. To improve this situation, all social actors should actively participate in the optimization actions. There are many measures that can be taken by the state, legal persons, and individuals, separately and together, at the public and private levels, to better integrate the responses to climate change and water management.

19.4.1 Public Level States should undertake more social obligations to the people for the private sector is more profit-seeking. Governments could promote more activities that have low short-term returns but long-term impacts on society as a whole, and regulate them uniformly with the public power granted by the people. States could adopt uniform legislation on general matters, such as a ban on grazing in arid areas to prevent further destruction of grasslands. The conversion of cropland into woods and grasslands and the establishment of nature reserves could also become a fundamental principle in combating climate change and protecting water resources. States could also legally require companies to report their water use and reduce the number of approvals for large-scale water-using businesses, such as golf courses and jeans factories. In addition, states can refer to the principle of marketization of carbon emissions and marketize enterprise’s share of water use to promote the reduction of greenhouse gas emissions and the reduction of water use in different industries. Regarding companies that use too much water, states could use high taxes to restrict them, thereby promoting the development of modern water-saving agriculture and recycling industries. Finally, water conservation targets could be included in the assessment of various government departments to promote the reduction of water waste in public institutions. Local discretion is also critical. In the current situation, states do not lack water resources protection legislation but need detailed provisions. Climate change and water resources can vary from region to region. Some areas are facing drought, while others are facing flooding. Each subordinate administrative unit may be granted varying degrees of discretion to adopt different plans and local regulations based on particular local circumstances. This measure will not only facilitate the management of regional climatic and water conditions but will also make it possible to discover, at a faster rate, programs suitable for national expansion through simultaneous experimentation in multiple locations. In addition to the above options, states should adopt a nature-based attitude. Wellprotected aquatic ecosystems may reduce greenhouse gas emissions and counter climate change (United Nations Water—at the center of the climate crisis 2023).

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Wetlands are effective carbon storage sites to moderate extreme weather and clean water resources (United Nations Environment Programme Action Climate for Nature). Also, it is important to understand the situation of local water resources, collect historical data, and forecast future conditions. When the government is unsure of when a water shortage will occur, its severity, and the relevant duration, the government may make plans with reference to the worst-case scenario. However, this approach can be wasteful if the worst scenario does not occur. Imperfect information will ultimately increase the economic losses attributed to changes in water resources. Climate predictions, such as those for El Niño, can substantially reduce economic losses associated with climate change. Early warning systems for floods, droughts, and other water-related disasters provide more than 10 times the return on investment and can significantly reduce disaster risk: 24-hour warnings of impending storms can reduce subsequent damage by up to 30 percent (World Meteorological Organization Early Warning systems must protect everyone within five years 2023).

19.4.2 Private Level There is no substitute for the role of the private sector when it comes to finance. While states can promote investment in a particular industry through policies, the long-term development of the industry still relies on the market-based investment behavior of private investors. Private sector investment in industries related to climate change and water resources management is essential for a sustainable response to climate change and the management of water resources. As far as ordinary citizens are concerned, it is very important to use water resources wisely in daily life. People can reduce water use in their homes and yards by repairing leaks, choosing products with water-saving features, and planting drought-resistant vegetation. In rural areas, measures such as timely cleaning of pesticide bags and reducing the use of chemical fertilizers can help reduce the pollution of water resources caused by nutrients and chemical pollutants. These actions could produce accumulative results in better managing water resources.

19.4.3 Multi-Actor Cooperation The cooperation of multiple subjects includes cooperation between similar actors and collaboration among different types of actors. As far as international cooperation is concerned, countries should actively cooperate in the face of the imperfection of relevant global treaties. Countries can work together to develop international conventions that comprehensively manage climate change and its impact on water resources. To ensure the enforceability of the conventions, they may integrate specific objectives, time points, and inspection mechanisms. In addition, states should ensure the security of water facilities that would have significant international impacts if destroyed.

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For the intentional destruction of such facilities, the nature of these acts as international crimes should be affirmed among states. In response to growing conflicts over water allocation in regions due to climate change, politicians must work together across national boundaries to balance the water needs of different states. The mutual confrontation between countries and groups of countries will only increase regional tensions and even break out into war. The principle of “common but differentiated responsibilities” in the UNFCCC can be used by upstream and downstream countries to reach agreements on the management and allocation of water resources in international rivers based on factors such as water flows in different basins and the water needs of each country. During the legislative process, international soft law can be transformed into legally binding international hard law. As far as the government and private sector are concerned, the private sector can set up related enterprises along with the government’s increasing focus on climate change and water conservation. These companies can provide tools, training, and assistance to government departments to help them assess the climate risks of their systems. For example, the construction of climate data collection systems and extreme event warning systems require the participation of Internet companies since the government may not have the advantage of talent resources compared to these companies. It could be concluded from the aforementioned analysis that in countering climate change and its impacts on water resources, every social actor should be mobilized. Public institutions could exert their power to uniformly regulate relevant matters and develop efficient measures through large-scale social experiments. Private actors could follow national policies and make their own efforts in countering climate change and managing water resources accumulatively.

19.5 Conclusion Climate change has serious impacts on water availability, water quality, and other water-related areas, thereby exacerbating transboundary water conflicts. In order to adapt, mitigate and address the climate change they face and the resulting water dilemma, countries have enacted laws, regulations, and policies to regulate water resources within their jurisdictions and at the international level. This has served to manage and protect water resources to some extent. In this paper, regarding the above-mentioned insufficient regulation and management, we propose an optimization idea, i.e., multi-actor participation. At the public level, states should undertake more social obligations, adopt unified legislation on overall matters, incorporate water conservation indicators into departmental assessments, and grant varying degrees of discretionary power to local governments. At the private level, the market investment and financing behavior of private investors is indispensable for sustainable water management and conservation, while the rational use of water by ordinary citizens for domestic purposes is also crucial. In addition, the multi-actor cooperation model aims at connecting similar actors or different types

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of actors and promoting inter-field cooperation, regional linkage, and governmententerprise coordination. In this way, social actors can jointly contribute to the conservation and management of water resources. This path of multi-corporate participation is also in line with China’s concept of “a Community with a Shared Future for Mankind.” Acknowledgements This study is supported by Youth Fund for Research in Humanities and Social Sciences: The Study on International Law Issues of Applying Floating Platforms to Safeguard Rights and Law Enforcement in the South China Sea (20YJC820049); Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai): Research on legal issues related to unmanned shin and marine unmanned equipment (SML2020SP005); Youth Academic Team in Humanities and Social Sciences of Wuhan University (Grant No. 4103-413100001).

References Bilgen A (2018) The Southeastern Anatolia project (GAP) revisited: the evolution of GAP over forty years. New Perspect Turk 58:125–154 Caretta M, Mukherji A, Arfanuzzaman M, Betts R, Gelfan A, Hirabayashi Y, Lissner T, Liu J, Gunn E, Morgan R, Mwanga S, Supratid S (2022) Chapter 4 water. In: Climate change 2022: Impacts, adaptation and vulnerability. contribution of working group II to the sixth assessment report of the intergovernmental panel on climate change, Cambridge University Press, UK and USA, pp 551–712 Coffey R, Paul M, Stamp J, Hamilton A, Johnson T (2018) A review of water quality responses to air temperature and precipitation changes 2: Nutrients, Algal Blooms, Sediment, Pathogens. J Am Water Resour Assoc 55(4):844–868 China Meteorological Administration State Council on the issuance of China’s national program to address climate change (2023). https://www.cma.gov.cn/2011xzt/2015zt/20150702/201507 0201/201507020103/201507/t20150702_286739.html. Last Accessed 12 June 2023 International Monetary Fund Dealing with Increased Risk of Natural Disasters: Challenges and Options (2023). https://www.imf.org/external/pubs/ft/wp/2003/wp03197.pdf. Last Accessed 12 June 2023 The National News Iran and Afghanistan face off over sharing Helmand waters (2023). https:// www.thenationalnews.com/mena/2023/05/28/iran-and-afghanistan-face-off-over-sharing-hel mand-waters/. Last Accessed 12 June 2023 Justia United States Law (2023). https://law.justia.com/us/. Last Accessed 12 June 2023 Knesset (2023) The Parliamentary Committee of inquiry on the Israeli water sector. https://m.kne sset.gov.il/EN/activity/mmm/me00530.pdf. Last Accessed 12 June 2023 Lall U, Johnson T, Colohan P, Aghakouchak A, Brown C, McCabe G, Pulwarty R, Sankarasubramanian A (2018) Chapter 3 water. In: Fourth national climate assessment volume II impacts, risks, and adaptation in the United States. United States Government Publishing Office, United States, pp 145–174 MacQuarrie P (2004) Water security in the Middle East: growing conflict over development in the Euphrates-Tigris Basin. The University of Dublin, Ireland Mueller A, Detges A, Pohl B, Reuter MH, Rochowski L, Volkholz J, Woertz E (2021) Climate change, water and future cooperation and development in the Euphrates-Tigris basin. Cascades Singapore Ministry of Law Homepage (2023). https://www.mlaw.gov.sg/. Last Accessed 12 June 2023

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The National People’s Congress of the People’s Republic of China China’s Policies and Actions to Address Climate Change (2023). http://www.npc.gov.cn/zgrdw/huiyi/ztbg/jjydqhbh1110/200908/24/content_1514538.htm. Last Accessed 12 June 2023 The National People’s Congress of the People’s Republic of China Environmental Protection Law of the People’s Republic of China (2023). http://www.npc.gov.cn/npc/c10134/201404/6c982d 10b95a47bbb9ccc7a321bdec0f.shtml. Last Accessed 12 June 2023 The National People’s Congress of the People’s Republic of China Water Law of the People’s Republic of China (2023). http://www.npc.gov.cn/npc/sjxflfg/201906/e1c5425950d5413780 5528c23b2d2986.shtml. Last Accessed 12 June 2023 The World Bank Floods and Droughts: An EPIC Response to These Hazards in the Era of Climate Change (2023). https://www.worldbank.org/en/news/feature/2021/06/17/floods-and-droughtsan-epic-response-to-these-hazards-in-the-era-of-climate-change. Last Accessed 12 June 2023 United Nations Economic Commissi FAQs (2023). https://unece.org/environment-policy/water/ about-the-convention/faqs. Last Accessed 12 June 2023 United Nations Egypt, Ethiopia, Sudan Should Negotiate Mutually Beneficial Agreement over Management of Nile Waters, Top Official Tells Security Council (2023). https://press.un.org/ en/2021/sc14576.doc.htm. Last Accessed 12 June 2023 United Nations Environment Programme Action Climate for Nature (2023). https://wedocs.unep. org/xmlui/bitstream/handle/20.500.11822/35360/NatClim.pdf. Last Accessed 12 June 2023 United Nations Office for Disaster Risk Reduction Water politics heat up under worsening climate in Afghanistan (2023). https://www.preventionweb.net/news/water-politics-heat-under-worsen ing-climate-afghanistan. Last Accessed 12 June 2023 United Nations Climate Change (2023). https://unfccc.int/most-requested/key-aspects-of-the-parisagreement. Last Accessed 12 June 2023 United Nations Water—at the center of the climate crisis, https://www.un.org/en/climatechange/sci ence/climate-issues/water. Last Accessed 12 Jun 2023 United States Environmental Protection Agency Water Management at EPA (2023). https://www. epa.gov/greeningepa/water-management-epa. Last Accessed 12 June 2023 World Meteorological Organization Early Warning systems must protect everyone within five years (2023). https://public.wmo.int/en/media/press-release/%E2%80%8Bearly-warning-sys tems-must-protect-everyone-within-five-years. Last Accessed 12 June 2023 Wu W, Lo M, Wada Y, Famiglietti J, Reager J, Yeh P, Ducharne A, Yang Z (2020) Divergent effects of climate change on future groundwater availability in key mid-latitude aquifers. Nat Commun 11:1–5

Chapter 20

Research on the Impact of Sediment Dredging Activities on the Lingding Bay of Pearl River Estuary, China Yao Xiaowei, Li Wendan, Xie Hualiang, and Li Huaiyuan

Abstract In recent decades, with the development of economy, human activities in tidal estuaries have increased dramatically. The Lingding Bay of Pearl River Estuary (LBPRE), where the Pearl River empties into the sea through four outlets, is a typical complex tidal estuary with the most frequent human activities, such as large-scale harbors and channels, sand-dredging activities, sea-crossing bridges and so on. Lots of precious measured data were employed to analyze the influence of sand-dredging activities on the LBPRE in this article. Firstly, based on the measured data, the underwater topographic changes caused by sand mining in recent 10 years are analyzed. Next, the temporal and spatial distribution of suspended sediment concentration (SSC) in LBPRE before and after sand mining is analyzed. Finally, the influence of sand mining on sediment siltation of surrounding projects is analyzed. The results show that, the large-scale disordered sand mining activities not only directly lead to a large number of irregular deep holes, change the local topography and the dynamic geomorphology of the “three shoals and two troughs”, but also produce a large amount of turbid water with high SSC which flows with the tidal current, increased the deposition thickness of the surrounding projects. Keywords Pearl River Estuary · Lingding Bay · Sand-mining activities · Sediment siltation · Deep foundation trench

Y. Xiaowei · L. Wendan (B) · X. Hualiang · L. Huaiyuan National Engineering Laboratory for Port Hydraulic Construction Technology, Tianjin Research Institute for Water Transport Engineering, M.O.T, Tianjin 300456, China e-mail: [email protected] L. Wendan Key Laboratory of Engineering Sediment of the Ministry of Transport, Tianjin Research Institute for Water Transport Engineering, M.O.T, Tianjin 300456, China Tianjin Survey and Design Institute for Water Transport Engineering, Tianjin 300456, China © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_20

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20.1 Introduction In recent decades, with the development of economy, human activities in tidal estuaries have increased dramatically. For example, large-scale land reclamation of estuarine shoals, sea-crossing bridges, construction of harbors and channels, water intake and drainage projects of Power Plant, as well as projects such as sand mining are also common in tidal estuaries (Bao et al. 2015; Han et al. 2016; He and Xin 2014, 2019; Hu 2016). Thus, the exploitation and utilization of tidal estuaries are widespread and ongoing. The Pearl River Estuary (PRE) is a complex tidal estuary of the Pearl River flowing into the sea through eight outlets. Lingding Bay is an important part of the Pearl River Estuary with the most frequent human activities (e.g., Fig. 20.1), such as large-scale harbors and channels, West Shoal reclamation, sand mining, channel dredging projects, and sea-crossing bridges and so on (Hu et al. 2010; Huang et al. 2014; Ji et al. 2012). There are several deep-water channels such as Guangzhou Channel (Lingding Channel) and Tonggu Channel of Shekou Port (e.g., Fig. 20.1). These ports and channels have played an important role in the exchange of goods and economic prosperity in South China (Jiang et al. 2012, 2015; Jin et al. 2017; Kuang et al. 2013). In addition, there are Hong Kong-Zhuhai-Macao Bridge (HZMB) and the Shenzhen-Zhongshan Link (SZL) two super sea-crossing bridges in the Lingding Bay of the Pearl River Estuary (LBPRE). The construction of HZMB started in 2009 and completed in 2018. It is about 35.6 km long and consists of a bridge of about 28.9 km long, two artificial islands called East Artificial Island and West Artificial Island, and an immersed tube tunnel of about 5664 m long running between the two artificial island (Li 2010; Li et al. 2008; Li and Li 2009). The Lingding Channel is located between these two artificial islands. The maximum excavation depth of the deep foundation trench (DFT) of immersed tube tunnel is 40 m, and the excavation width is 41.9 m. The immersed tube tunnel consists of 33 tunnel units. The most difficult project is that the docking error of adjacent units needs to be less than 4 cm. Therefore, the deposition thickness of DFT plays a key role in the precise docking of tunnel units. Sand mining has become an important human activity in the LBPRE in recent years (Li et al. 2017, 2019). Some Remote Sensing (RS) images show that, there were a large number of dredgers in the northeast area of Neilingding Island from 2014 to 2018. It results in a great increase of SSC, and the turbid water will move and spread with tidal current, which brings heavy burden to the dredging and safety construction of surrounding projects. In recent years, based on the measured data and numerical simulation method, a large number of studies have been carried out on the impact of sand mining on the surrounding environment (Li and Qiao 2012). In this article, the effect of sanddredging activities on the LBPRE was analyzed based on a large number of precious measured data in the past 10 years, including underwater topography data, temporal

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Fig. 20.1 Sketch map of Lingding Bay in the Pearl River Estuary

and spatial distribution of SSC caused by sand mining and the siltation of DFT of HZMB and so on.

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20.2 Study Area The Lingding Bay is a trumpet-shaped estuary with an area of about 1000 km2 (Jiang et al. 2015). The bay head is about 4 km wide and the bay mouth is about 30 km wide (e.g., Fig. 20.1). The Pearl River flows through Humen, Jiaomen, Hongqimen, Hengmen (four eastern outlets) into the Lingding Bay, the largest estuary of the Pearl River. Runoff and sediment discharged into Lingding Bay accounts for 61% and 54% of the total amounts discharged from the Pearl River, respectively. The tide in the Lingding Bay changed from irregular diurnal tide to irregular semidiurnal tide after it entered the bay from the South China Sea. The average tidal range is less than 2.0 m. Constrained by coastline and seabed topography, the tidal current in Lingding Bay is basically north–south reciprocating flow. According to synchronous hydrometric measurement data of a spring tidal cycle at 11 gauging stations in June 2009 during flood season around Neilingding Island, the mean vertically averaged velocities range from 0.16 to 0.79 m/s, the maximum vertically averaged velocities range from 0.33 to 1.47 m/s. The current velocities at ebb tides are generally greater than those at flood tides. According to measured data of spring tidal cycles during flood and dry seasons in 2009, the vertically averaged SSC during range from 0.024 to 0.131 kg/m3 . The average median size d50 of the suspended sediment is about 0.007 mm, which is categorized as silt.

20.3 Methods Underwater topography data of the northern part of LBPRE measured in 2007, 2011 and 2016 were collected. The underwater topography data was unified to the Local theoretical bathymetrical datum. Digital elevation models (DEM) were generated with 50 × 50 m grids using the Kriging interpolation method. Isobaths maps of 0 m, −5 m, −10 m, −15 m, −20 m, −25 m, and −30 m were drawn for the different years using Golden Software. Then, the topography change and the evolution character caused by sand-dredging activities were analyzed for different years. The sampling works were organized to explore the surface-layer SSC and d50 of the suspended load in sand mining zone on January 6 to 8, 2015. The sampling works were carried out in three times, with a total of 20 sampling points. Table 20.1 provides 10 observation data of these points. The SSC tour-gauging from the northeast side of Neilingding Island to the immersed tube tunnel of HZMB during ebb tide in the daytime from January 8 to August 10, 2015 has been implemented. COMPACT-CTD turbid meter was used for bottom-layer SSC measurement. The tour-gauging was conducted once a day during the sand mining period and once every three days during the sand mining closed period. The length of the tour-gauging route is 20 km, and 20 stations (e.g.,

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Table 20.1 The coordinates of sampling points No

Longitude

Latitude

Data

d 50 (mm)

SSC (kg/m3 )

1#

113°47.927'

22°26.108'

2015/1/6

0.0507

1.265

2#

113°49.260'

22°26.067'

2015/1/6

0.0501

1.672

3#

113°49.998'

22°25.165'

2015/1/6

0.0320

0.898

4#

113°46.010'

22°23.453'

2015/1/7

–

0.920

5#

113°46.328'

22°24.796'

2015/1/7

0.0355

0.626

6#

113°47.476'

22°26.252'

2015/1/7

0.0331

0.780

7#

113°48.748'

22°25.770'

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0.0305

1.614

8#

113°46.207'

22°25.987'

2015/1/8

0.0286

2.5 (maximum)

9#

113°46.635'

22°26.334'

2015/1/8

0.0278

10#

113°48.130'

22°26.751'

2015/1/8

0.0083

Fig. 20.1) were arranged along the route with spacing between 500 and 1500 m. Points D1, D13 and D20 were located to the northeast of Neilingding Island, Tonggu Channel and to the north of the DFT respectively. Underwater topography data of tube element 18 to tube element 26 of HZMB was measured by multi beam method. The measurement data was divided into two stages, with first stage from December 17 to January 2, 2015 and second stage from February 11 to March 29, 2015. Then, the underwater topography data of each tunnel element was averaged and the deposition thickness of one day was calculated. In addition, the siltation data of silting boxes placed at the seabed of tube element 18 and tube element 19 were collected.

20.4 Results and Discussion 20.4.1 Spatial and Temporal Location of Sand Dredgers A large number of satellite images from 2010 to 2019 show that, the sand mining area of LBPRE has changed significantly from north to south. In December 2010, The sand dredger was mainly located in the west of the Shenzhen Airport. In December 2013, most of the sand dredgers moved south to the west of Dachan Island. However, in December 2014, a large number of dredging ships appeared in the northeast of Neilingding Island. From 2015 to 2019, sand mining ships were mainly concentrated near Neilingding Island. According to the statistic of field survey data, the number of sand dredgers to the northeast of Neilingding Island per day was ranged from 14 to 56 from January 2015 to May 2015. It was basically between 10 and 46 from August 2016 to March 2017 except the Spring Festival. In addition, according to the AIS monitoring data and

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RS images, the number of dredgers per day was about 17 to 38 from April 2017 to February 2018.

20.4.2 Sand Mining Zones Approved by Local Government Sand-dredging activities have existed in LBPRE for a long time. According to relevant data, 18 sand mining zones were approved by the local government in LBPRE in 2012 (e.g., Fig. 20.2a). G1 to G8 were under the jurisdiction of Guangdong Maritime Bureau, and S1 to S10 were under the jurisdiction of Shenzhen Maritime Bureau. The area of 18 sand mining zones was 983 hectares. G2 and G3 were located in the Jiaoyi Bay. G1, G4 and G7 were located in the west shoal. The rest were arranged on the middle shoal and Fanshi Channel. While in recent years, the number of approved sand mining zones has been reduced to 7 in 2014 (e.g., Fig. 20.2b). Sand mining zones in LBPRE approved by the local government were predominantly distributed in Fanshi Shoal. The area of 7 sand mining zones was 382 hectares.

Fig. 20.2 Position of sand mining zones a in 2012; b in 2014 approved by government

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Fig. 20.3 Water depth of 2007, 2011 and 2016, showing the shape and depth of sand-dredging pits

20.4.3 Topography Changes and Evolution Characteristics Caused by Sand Mining The underwater topography data of the northern part of LBPRE measured in 2007, 2011 and 2016 were compared and analysed (e.g., Fig. 20.3). From 2007 to 2011, the sand-dredging activities were mainly concentrated in the middle shoal. There were some sand-dredging pits with different depths and irregular shapes, which were connected with each other. It was about 15 km long from north to south and 4 km from east to west. The water depth of sand mining pits generally increased by more than 6 m, and the local water depth increased by 15 m. From 2011 to 2016, the sand-dredging pits continued to extend southward, with a length of about 18 km. There were some new sand-dredging pits to the northeast of Neilingding Island and the west of Mazhou Island. The water depth of these newly sand-dredging pits has generally increased by 5 to 15 m. There was a certain tendency of siltation in the excavation pits after stopping sand mining. The deposition thickness of sand-dredging pits in the north part of the middle shoal was between 0.5 and 8 m from 2011 to 2016.

20.4.4 Spatiotemporal Distribution of SSC Caused by Sand Mining The surface-layer SSC of sampling points in the sand mining zones ranged from 0.63 to 2.5 kg/m3 by sand dredging and sand washing. The median size (d50) of suspended sediments was between 0.013 to 0.05 mm. The turbid water with high SSC caused by sand mining could be seen to extend 4 km southward along the ebb tide. The sand dredgers near Neilingding Island were chaotic, and the number and operation

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intensity of sand dredgers were uncertain. In a word, the turbid water produced by sand mining near Neilingding Island was startling. In the four periods of sand mining, closure, recovery, and closure, the corresponding SSCs were large, small, large, and small, respectively (e.g., Table 20.2). The mean SSC of D20 was 53% lower than that before (e.g., Fig. 20.4). The sandmining activity recovered on May 2, 2015, the mean SSC values were 0.546 kg/m3 and 0.16 kg/m3 of D02 and D20, respectively. The mean SSC was about 0.06 kg/ m3 of D02 from May 21 to August 10 during the closure period. Even under the influence of the strong runoff of the Pearl River, the mean SSC of D20 was 62% lower than that in the recovery period. The sand-mining activities in the middle shoal and the west shoal not only resulted in many irregular deep holes with water depths increasing from −5 m to −15 m, but also produced large amount of muddy water with high SSC. Among them, the coarser sediment was deposited near the sand mining zone, while the finer sediment had a far-reaching impact and could then be transported to the water area beyond 15 km with the ebb tide. Table 20.2 Mean suspended sediment concentrations in different periods at tour-gauging points Tour-gauging points

SSC (kg/m3 ) Sand mining 1/8–2/9

Closing 2/13–4/30

Recovery 5/1–5/20

Closure 5/21–8/10

D01

0.746

0.041

0.506

0.055

D02

0.799

0.042

0.546

0.060

D03

0.630

0.047

0.571

0.064

D04

0.547

0.048

0.486

0.070

D05

0.456

0.049

0.443

0.076

D06

0.402

0.050

0.319

0.079

D07

0.335

0.055

0.231

0.085

D08

0.345

0.056

0.243

0.083

D09

0.343

0.052

0.220

0.081

D10

0.275

0.054

0.224

0.079

D11

0.186

0.052

0.220

0.084

D12

0.146

0.045

0.240

0.088

D13

0.129

0.033

0.211

0.057

D15

0.072

0.035

0.170

0.056

D16

0.065

0.040

0.171

0.061

D17

0.072

0.038

0.148

0.061

D18

0.072

0.039

0.159

0.063

D19

0.072

0.038

0.162

0.063

D20

0.075

0.035

0.160

0.061

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Fig. 20.4 Change of suspended sediment concentrations at D02, D08, D13 and D20 before and after sand mining

20.4.5 Siltation in DFT Before and After Sand Mining The increase of SSC caused by sand excavating is bound to affect the siltation of surrounding projects, especially the HZMB. The construction of HZMB began in December 2009, however, forced to stop due to abnormal siltation during floating installation of tunnel unit 15 in November 2014. The abnormal siltation seriously restricted the construction progress of the HMZB, which is an urgent problem to be solved. Here we mainly collect the DFT data of the HZMB. According to the multi-beam measurement results of DFT (average value of each tube element) from December 17, 2014 to January 28, 2015 before the closure of sand mining and from February 11 to March 29, 2015 after the closure of sand mining (e.g., Fig. 20.5). The average accumulative deposition thickness of tube elements 18 to 26 for 14 days was 0.55 m, equivalent to 3.7 cm per day during sand mining period from December 17, 2014 to January 28, 2015.The average accumulative deposition thickness of tube elements 18 to 26 for 14 days was 0.19 m, equivalent to 1.3 cm per day during sand mining closing period from February 11 to March 29, 2015.The average

Fig. 20.5 Siltation in deep foundation trench of Hongkong-Zhuhai-Maocao Bridge before and after sand mining

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deposition thickness during sand mining closing period was 65% lower than that in sand mining period. The above conclusion has been confirmed by the siltation data of silting boxes on the seabed of DFT. The DFT of HZMB crosses Lingding Channel and Tonggu Shoal from west to east. The sea area on the west side of Tunnel Unit 15 is mainly the Lingding Channel, and the water depth is relatively deep. The tidal current and SSC movement in the Lingding Channel is controlled by the continental shelf water, and the sediment are difficult to deposit. Moreover, due to the large tidal current velocity, the terrain remains stable for a long time. However, the eastern part of DFT passes through the Tonggu Shallow, with relatively shallow water depth, and there is a significant depth difference between the DFT and its ambilateral beach surface. Due to weak hydrodynamic forces and high SSC caused by sand mining, the area is in a siltation state. Therefore, with tunnel unit 15 as the boundary, the difference in terrain and hydrodynamic characteristics between the eastern and western sea area of DFT is the cause of abnormal silt.

20.5 Conclusions The influence of unpredictable disordered project such as sand mining on estuary area is an interesting and meaningful topic. In this article, the effect of sand-dredging activities on the LBPRE was analyzed based on a large number of precious measured data in the past 10 years. The LBPRE is a typical complex tidal estuary with the most frequent human activities, including sand-mining activities, HZMB, SZL and so on. Sand-mining activities have existed in LBPRE for a long time. Since 2011, there were large-scale obviously disordered sand-mining activities in the middle shoal and west shoal. This not only leaded many irregular deep holes, but also produced a large amount of turbid water with high SSC. The turbid water could be transported to HZMB with ebb tidal currents, which will obviously increase the deposition thickness of DFT by 65%. In addition, a high-precision numerical simulation of sediment siltation in DFT affected by sand mining in Pearl River Estuary should be developed.

References Bao M, Bao XW, Yu HM, Ding Y (2015) Tidal characteristics in the Wenzhou offshore waters and changes resulting from the Wenzhou Shoal reclamation project. J Ocean Univer China 14(6):931–940 Han XJ, Yang SS, Li MG, Yan Y (2016) Study on the sea engineering technology of Hong Kong– Zhuhai–Macao Bridge. Beijing, China Communications Press Co., Ltd, pp 19–50 (in Chinese) He J, Xin WJ (2014) Hydrodynamic impact on Pearl River estuary from HZM Bridge. Appl Mech Mater 488–489:475–478

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He J, Xin WJ (2019) Analysis and numerical simulation of abnormal siltation in foundation trench of immersed tube tunnel of Hongkong-Zhuhai-Macao Bridge. Adv Water Sci 30(6):823–833 Hu WW (2016) Impact of sand excavation in river way on hydrology and ecological environment of middle and lower reaches of Hanjiang River. Wetland Sci 14(2):157–162 Hu DL, Yang QS, Wu CY, Bao Y, Ren J (2010) Changing water and sediment dynamics in Pearl River network and consequences on water and sediment regimes in the Lingdingyang Estuary. Adv Water Sci 21:69–76 (In Chinese) Huang WD et al (2014) Research on sediment problems related to water intake and drainage project of power plants. J Yangtze River Scient Res Instit 31(8):1–5 Ji RY, Xu Q, Jia LW, Mo SP (2012) Effects on the hydrodynamics caused by artificial islands of the Hong Kong–Zhuhai-Macao Bridge. Appl Mech Mater 204–208:2085–2090 Jiang CJ, Yang QS, Dai ZJ, Li JF (2012) Patial and temporal characteristics of water level change and its causes in the Zhujiang Delta in recent decades. Acta Oceanol Sin 34(1):46–56 Jiang F et al (2015) Hydrological and sediment effects from sand mining in Poyang Lake during 2001–2010. Acta Grographic Sinca 70(5):837–845 Jin ZW, Zuo CS, Wang ZZ (2017) Impact of Phase III project of Maji Mountain Port on sediment siltation in adjacent sea area. Acta Oceanol Sin 36(12):111–118 Kuang CP, Huang J, Lee JHW, Gu J (2013) Impact of large-scale reclamation on hydrodynamics and flushing in Victoria Harbor, Hongkong. J Coastal Res 291:128–143 Li MG (2010) The effect of reclamation in areas between islands in a complex tidal estuary on the hydrodynamic sediment environment. J Hydrodyn 22(3):338–350 Li MG, Li WD (2009) Three dimensional tidal current numerical model of the Oujiang Estuary. Acta Oceanol Sin 28(3):17–25 Li PR, Qiao PN (2012) Calculation of shrinking and vanishing of Lingdingyang Sea at the Pearl River Estuary. Tropical Geography 32(3):260–262 (In Chinese) Li MG, Han XJ, Yang SS, Li WD (2008) Study on tidal current and sediment problems of deepwater channel project of Nansha Harbor District of Guangzhou Port. Chinese J Hydrodyn 23(3):321– 330 (in Chinese) Li MG, Xin WJ, Xu Q, Han XJ (2017) Influence of Hong Kong-Zhuhai-Macao Bridge on hydrodynamic sediment environments and harbours and navigational channels in Lingdingyang Firth of the Pearl River. Port Waterway Eng 10:67–73 Li MG, Yan Y, Han XJ, Li WD (2019) Physical model study for effects of the Hong Kong–Zhuhai– Macao bridge on harbors and channels in Lingdingyang Bay of the Pearl River Estuary. Ocean and Coastal Managem 177:76–86

Chapter 21

Distribution Characteristics of Seabed Sediment in Anpu Bay of Guangdong Province, China Xiaowei Yao, Hualiang Xie, Huaiyuan Li, and Zhiyuan Han

Abstract As the most important information of seabed sediment, the grain size parameters can indicate depositional environment and reflect the coupling mechanism of dynamic-deposition-topography action. Based on 46 seabed sediment samples data and bathymetric data in Anpu Bay of Guangdong Province, China, the grain size parameter of Anpu Bay has been studied and its influence on the seabed stability of Anpu Bay has been analyzed. The results are showed as follows: (1) Seabed sediment types of Anpu Bay are mainly sandy sediment with median grain size of 0.28 ~ 0.92 mm, and only a few clayey or silty sediments with median grain size less 0.06 mm distribute in the central bay. (2) Seabed sediments in Anpu Bay distribute with discontinuous characteristics from west to east, which indicate that seabed sediment is not active. (3) Due to limited sediment sources, weak hydrodynamic conditions, and inactive seabed sediment, the deep trough in Anpu Bay experienced a slight silting process and the seabed maintain stability for a long time. Keywords Seabed sediment characteristics · Sediment transportation · Seabed stability · Anpu Bay

21.1 Introduction As the most important information of seabed sediment, the grain size parameters can indicate depositional environment and reflect the coupling mechanism of dynamicdeposition-topography action. Therefore, based on a combination of characteristics of seabed sediment grain size parameters, it can help understand sedimentary environment (Han and Li 2016), such as sediments deposition condition, sediment sources, X. Yao · H. Xie (B) · H. Li · Z. Han Tianjin Research Institute for Water Transport Engineering, Ministry of Transport, Tianjin 300456, China e-mail: [email protected] H. Xie · H. Li · Z. Han Key Laboratory of Engineering Sediment of Ministry of Transport, Tianjin 300456, China © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_21

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Fig. 21.1 Sketch map of research zone and seabed sampling stations

sediment transport trends etc.. Anpu Bay locates in western Guangdong Province, and at northwestern coastline of Leizhou Peninsula (see Fig. 21.1). Anpu Bay, with a length of approximately 15 km from west to east a width of 12 km from north to south, and is only open to Beibu Gulf at west (Li 1986). There is a deep trough extend to the top of the bay from deep water of open sea in the bay. According to long-term economic development plan of Guangdong Province, Anpu Bay will be developed as a deep water harbor and the deep trough will be developed for deep-water channel. Therefore, it is necessary to study seabed sediment characteristics in Anpu Bay for understanding its sedimentary environment and seabed stability. Based on mass filed seabed sediment data of Anpu Bay, this article focus on the sediments distribution characteristics, hydrodynamics and sedimentary environment, and isobaths changes etc., and will provide research basics for the utilization and development of Anpu Bay.

21.2 Data and Methods In July 2014, 46 seabed sediment samples were sampled using grab sampler in Anpu Bay, with sampling stations covering the whole bay (sampling station see Fig. 21.1). All the samples were sent to laboratory for particle size analysis using BT9300 laser particle size analyzer. Seabed sediments were classified and named using

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Shepard sediment classification method (Shepard 1954). The grain size parameters including median grain size (d50), sorting coefficient (Qdϕ) and skewness (Skϕ) were calculated by using Folk and Ward formula (Folk and Ward 1957). One Chinese navigation charts measured in 1984 and one bathymetric data measured in 2014 were collected. Then, the isobaths maps of 0, 2, 5 and 10 m were drawn for the different years by using ArcGIS software.

21.3 Results 21.3.1 Distribution of Seabed Sedimentary Types Based on seabed sediment data, seabed sediment in Anpu Bay contend 5 types, including coarse-medium sand, medium-fine sand, fine sand, sand-silt–clay, and silty clay (see Table 21.1). The sandy sediments, including coarse-medium sand, mediumfine sand, and fine sand with medium grain size (d50) ranging from 0.28 mm to 0.92 mm, are the dominant sediment types in the whole bay, which account for 65% of total sediment samples. The silty sediments including sand-silt–clay, account for 22% of all samples, with median grain size (d50) ranging from 0.01 mm to 0.06 mm. The clayey sediments including silty clay, only account for 13% of all samples, with median grain size ranging from 0.004 to 0.015 mm. The planar map of seabed sedimentary types in Anpu bay is showed in Fig. 21.2. Medium-fine sand is widely distributed in most areas except for the central bay. Coarse-medium sand is only distributed in the deep trough near the Jiaotou. Fine sand is distributed in the water area near the mouth of Anpu River in the eastern bay. Fine sediments including sand-silt–clay and silty clay are distributed in the deep trough water area and adjacent shallow water areas on the central bay of the bay mouth. Thus, the distribution of sediment types in the sea area from west to east shows a discontinuous characteristic of sand ~ silt ~ clay ~ sand. Table 21.1 Statistics of seabed sediment in Anpu Bay Sedimentary type

Percentage (%)

Grain parameter

Grain content (%)

D50 (mm)

Qdϕ

Sand

Silt

Clay

Coarse-medium sand

13.0

0.49

0.49

96.9

4.1

0

Medium-fine sand

45.7

0.30

0.56

89.8

11.2

0

6.5

0.147

0.41

97.1

2.9

0

Sand-Silt–Clay

21.7

0.029

2.46

34.0

28.0

37.7

Silty clay

13.0

0.008

2.47

17.6

33.8

48.6

100.0

0.22

1.12

74.1

11.6

14.3

Fine sand

In Sum

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Fig. 21.2 Sketch of distribution of seabed sedimentary types

21.3.2 Distribution of Median Grain Size The median grain size (d50) of all seabed sediments ranges from 0.004 to 0.68 mm in Anpu bay. The fine sediments with D50 less than 0.06 mm, mainly distribute at the central bay (Fig. 21.3a). The sandy sediments with D50 ranging from 0.11 to 0.68 mm, widely distribute at shallows and grooves in the whole bay. From the distribution map of median grain size (d50) (see Fig. 21.3a), the d50 ranges from 0.108 to 0.423 mm in the eastern bay, ranges from 0.004 to 0.062 mm in the deep channel and adjacent shallow water areas of the central bay, and ranges from 0.3 to 0.68 mm in the shallow water area on near Jiaotou. Overall, the planar distribution of the d50 for seabed sediments in Anpu Bay shows a variation characteristics of coarse ~ fine ~ coarse from west to east.

21.3.3 Distribution of Sorting Coefficient The sorting coefficient (Qdϕ) of seabed sediments ranges from 0.28 to 2.8 in Anpu bay. From the planar distribution of sorting coefficients (see Fig. 21.3b), it can be seen that the sorting coefficients in the western, southern, and eastern parts of the bay are basically less than 0.6, indicating a very good sorting degree; The sorting coefficients of the deep trough and adjacent shallow waters in the central bay are greater than 2.2, indicating a poor sorting degree; The sorting coefficient of the northern and eastern regions of the bay ranges from 0.6 to 1.4, indicating a good degree of sorting. Overall, the sorting degree of seabed sediment in the bay area shows a variation characteristics of good ~ poor ~ good sorting from west to east.

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Fig. 21.3 Planar distribution of the median particle size a and sorting coefficient b

21.3.4 Distribution of Grain Content The sand content of seabed sediment in Anpu Bay ranges from 16.6 to 100.0%. From the planar distribution of sand content (see Fig. 21.4a), it can be seen that the sand content in the deep trough and adjacent shallow water areas in the central bay is very low ranging from 16.6 to 49.0%, and that of the other regions in the bay is basically above 80%. The distribution of sand content in this sea area shows a variation characteristics of high ~ low ~ high from west to east. The silt content of seabed sediment in Anpu Bay ranges from 0.0 to 40.0%. From the planar distribution of silt content (see Fig. 21.4b), it can be seen that that the silt content in the deep trough and adjacent shallow water areas in the central bay range from 19 to 40.0%, and that of the other regions in the bay is basically below 5%. The distribution of silt content in this sea area shows a variation characteristics of low ~ slight high ~ low from west to east. The clay content of seabed sediment in Anpu Bay ranges from 0.0 to 53.0%. From the planar distribution of clay content (see Fig. 21.4c), it can be seen that that the clay content in the deep trough and adjacent shallow water areas in the central bay

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Fig. 21.4 Sketch of sediment content contours of seabed sediment (a: Sand content; b: Silt content; c: Clay content)

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range from 26 to 53.0%, and that of the other regions in the bay is basically 0. The distribution of clay content in this sea area shows a variation characteristics of low ~ high ~ low from west to east.

21.4 Discussion 21.4.1 Hydrodynamic Conditions The prevailing wave direction in Anpu Bay sea area is NNE, with a frequency of 16.28%. The secondary prevailing wave directions are NE and N, with frequencies of 12.86% and 11.45%, respectively. The strong wave direction is ESE, and its H4% is about 4.0 m, corresponding to an average wave period of 6.9 s. The wave frequency of H4% < 1.0 m is 92.6%. The waves are mainly wind waves, with an average annual wave height of 0.46 m. As a semi-enclosed bay, Anpu Bay is mainly influenced by SSW-W waves from the open sea. During the propagation of waves into the bay, the wave height decreases due to factors such as refraction, shallow water deformation, and seabed friction, resulting in a smaller wave height inside the bay. As a semi-enclosed bay with main deep trough, the tidal current in Anpu Bay is restricted by shoreline shape and underwater topography, and flow reciprocally along the deep trough (see Fig. 21.5). During flood tide, tide prism enters the bay from the west, with flow direction from WSW to ENE. During ebb tide, the flow direction is the opposite. The average flow velocity of the flood tide is 0.19–0.38 m/ s, and the average flow velocity of the neap tide is 0.29–0.46 m/s. The maximum flow velocity of flood tide is 0.37–0.42 m/s, and the maximum flow velocity of neap tide is 0.42–0.92 m/s.

21.4.2 Sedimentary Environment Suspended sediment concentration (SSC) in Anpu Bay is very low and ranges from 0.01 to 0.16 kg/m3 with an average value of 0.035 kg/m3 . The median grain size of suspended sediment in this sea area ranges from 0.0036 to 0.0046 mm, with an average value of 0.0038 mm; The clay content of suspended sediment ranges from 43.3 to 54.3%, with an average value of 50.8%; The main type of suspended sediment is silty clay. Thus, in Anpu Bay, suspended sediment type are mainly silty sediment, and seabed sediment type are mainly as sandy sediment, so seabed sediment in shallows and deep grooves is difficult to transport under action of current and wave, and seabed sediment is not active. There are 3 small mountainous rivers flowing into Anpu Bay, including Jiuzhou River, Anpu River, and Yanggan River. The Jiuzhou River as the largest river, has a total length of 162 km, with an annual runoff of 1.84 billion m3 and an annual

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Fig. 21.5 Flow ellipses during spring tide in Anpu Bay

sediment amount of 377,000 tons. Due to the construction of the reservoirs in the upper reaches, the amount of sediment flowing into Anpu Bay is very small, so its sediment resources is quite limited. Therefore, the sediment mount from rivers in the sea area is relatively limited.

21.4.3 Analysis of Seabed Stability According to planar map of isobaths changes in Anpu Bay from 1984 to 2014 (Fig. 21.6), the seabed in the bay have the following characteristics of involvement: The 0 m isobaths in the eastern bay have moved westward with a slightly silting trend indicating that a small amount of land-based sediment from the small rivers discharged into the bay; The 0 m isobaths in the northern and southern bay have no obvious change. The 2, 5, and 10 m isobaths in the bay have no obvious changes with position and shape remaining stable. Thus, small amount of sediment mainly accumulates in shallow areas above 2 m isobaths, while deep trough waters below 2 m remain stable. The annual average wave height in this sea area is 0.46 m, and the frequency of wave heights less than 1 m exceeds 92.6%. Therefore the impact of wave dynamics on beach sediment is relatively weak. The average flow velocity at the bottom of Anpu Port is basically less than 0.3 m/s, so it is difficult for the sediment in the deep channel and shallow beach in the bay to move influenced by tidal currents. In all, the wave and current dynamics in the bay are not strong, and the sediment in the shallow shoals and deep troughs in the bay is difficult to initiate under the normal conditions, which is also the main reason for the low sediment content in the water bodies in the bay.

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Fig. 21.6 Isobaths changes in Anpu Bay from 1984 to 2014

In all, due to limited sediment sources, weak hydrodynamic conditions, and inactive seabed sediment, the deep trough in Anpu Bay experienced a slight silting process and the seabed maintain stability for a long time.

21.5 Conclusion Based on 46 seabed sediment samples data and bathymetric data in Anpu Bay of Guangdong Province, China, the grain size parameter of Anpu Bay has been studied and its influence on the seabed stability of Anpu Bay has been analyzed. The results are showed as follows: (1) Seabed sediment types of Anpu Bay are mainly sandy sediment with median grain size of 0.28 ~ 0.92 mm, and only a few clayey or silty sediments with median grain size less 0.06 mm distribute in the central bay. (2) Seabed sediments in Anpu Bay distribute with discontinuous characteristics from west to east, which indicate that seabed sediment is not active. (3) Due to limited sediment sources, weak hydro-dynamic conditions, and inactive seabed sediment, the deep trough in Anpu Bay experienced a slight silting process and the seabed maintain stability for a long time.

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References Folk RL, Ward WC (1957) Brazos River bar: a study in the signification of grain size parameters. J Sediment Petrol 27:3–27 Han ZY, Li MG (2016) Characteristics and transport trend of seabed sediment in Changxingdao sea area of Dalian. J Sedim Res 2:40–45 Li CC (1986) Geomorphological features of embayed coast in South China. Acta Geogr Sin 41(4):311–320 Shepard FP (1954) Nomenclature based on sand-silt-clay ratios. J Sediment Petrol 24(3):151–158

Chapter 22

Evaluation of Urban Livability—A Case Study of Kunming City, China Junmei Li, Qing Hui, Runqiu Fei, Guoqi Qian, Jinyu Liu, Ruixue He, and Jing Zhou

Abstract Urban livability is an important index to measure the comprehensive strength of a city and the level of ecological civilization construction, and is also an important issue to pay attention to people’s livelihood. The study of urban livability is an important content of the sustainable development research of urban environment, economy and society. Kunming, as the capital city of Yunnan Province and the venue of COP15 Conference, has been striving to build an exemplary city in the forefront of ecological civilization construction. As such, Kunming City is selected as a case study of urban livability evaluation. From the five aspects of urban safety, environmental health, convenience of living, travel convenience and residential comfort, the objective evaluation index system and subjective evaluation index system of urban livability are constructed to evaluate the city livability in Kunming. The results show that in recent 5 years, the comprehensive score of objective evaluation of urban livability in Kunming has an increasing trend, and the degree of constructed livability increases year by year. The overall score of livability satisfaction of residents in Kunming city is 4.35, which is between Neither Satisfied or Dissatisfied and Somewhat Satisfied. The top five indexes, from high to low, are: convenience of living, environmental health, residential comfort, urban safety and travel convenience, while the scores of urban safety and travel convenience are lower than the overall resident’s satisfaction score. Finally, this paper comprehensively analyzes the subjective and objective city livability evaluation results and puts forward feasible J. Li · Q. Hui · J. Liu · J. Zhou School of Ecology and Environmental Sciences and Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, Yunnan University, Kunming 650091, P.R. China J. Li Think Tank On Ecological Civilization Construction in Yunnan, Kunming 650091, P.R. China R. Fei · G. Qian (B) School of Mathematics and Statistics, The University of Melbourne, VIC 3010, Melbourne, Australia e-mail: [email protected] R. He School of Statistics and Mathematics, Yunnan University of Finance and Economics, Kunming 650221, P.R. China © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_22

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suggestions to improve livability construction in Kunming, including strengthening the urban road construction, improving the urban safety level, increasing the educational and medical facilities, this will help to keep sustainable development of urban environment, economy and society. The study combines environmental, economic and social sustainable development ideas into urban livability studies, to enrich the study cases of city livability evaluation system, and to provide examples for other cities to follow. Keywords Urban livability · Indicator system · Entropy method · Subjective and objective evaluation · Kunming City

22.1 Introduction Urban livability is an important index to measure the comprehensive strength of a city and the level of ecological civilization construction, and is also an important issue to pay attention to people’s livelihood. The study of urban livability is an important content of the sustainable development research of urban environment, economy and society. Kunming, as the capital city of Yunnan Province and the venue of COP15 Conference, has been striving to build an exemplary city in the forefront of ecological civilization construction. As such, Kunming City is selected as a case study of urban livability evaluation. From the five aspects of urban safety, environmental health, convenience of living, travel convenience and residential comfort, the objective evaluation index system and subjective evaluation index system of urban livability are constructed. An entropy method is used to calculate the specific weight of each index, and the composite index method is used to calculate the objective evaluation comprehensive score of Kunming city livability. Through the questionnaire survey, relevant data of resident’s satisfaction were collected to calculate the score of resident’s satisfaction. Finally, this paper comprehensively analyzes the subjective and objective city livability evaluation results and puts forward feasible suggestions to improve livability construction in Kunming, this will help to keep sustainable development of urban environment, economy and society. The study combines environmental, economic and social sustainable development ideas into urban livability studies, to enrich the study cases of city livability evaluation system, and to provide examples for other cities to follow. It is generally accepted that the idea of the ‘liveable city’ originated with the British social activist Ebenezer Howard’s ‘The Garden City of Tomorrow’ published in 1898, which set out the theory and practice of the ‘garden city’. The theory and practice of the ‘city of tomorrow’ provided the direct theoretical basis for the creation of the ‘liveable city’ (Xuan and Hui 2018). We should give to the lives of our citizens and their humanity in the development of our cities today (Lixin 2016). A livable city is defined as a city with nice living environment, sustained ecological environment and a high social production level. Especially, apart from comfortable residences, a livable city should have high accessibility to various infrastructural

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resources including transportation, education and healthcare (Xianpeng 2012). Some of the world’s leading publications also rank the most livable cities around the world. For example, the Economist Intelligence Unit annually ranks the world’s most livable cities, in which Melbourne, Australia has repeatedly been ranked as the top on the list, sitting as an example for livable cities around the world (Xid et al. 2017). Importantly, with rising attentions and continuous discussions, city livability has become a critical part of urban planning and development, and hence a field worth for deeper study and research. City livability has been studied by past scholars in various aspects. Wangming et al. point out that research on urban livability evaluation methods should be emphasized (Wangwu and Xinyue 2000). Liping clarifies the concept of a livable city, stating that a livable city is a city that integrates economic, environmental, cultural and social development and enriches the spiritual life of its residents while satisfying their material needs (Xid et al. 2017). Wenzhong enriches the concept of a livable city, arguing that a livable city is a city with high living comfort, good environmental quality, good infrastructure, efficient and environmentally friendly production, and where people are satisfied with their current life (Liping 2001). In his ‘Exploring the connotation and evaluation index system of a livable city’, he proposes five dimensions of urban livability: safety, health, convenience, accessibility and comfort. In a study of urban livability in Melbourne, Sidh et al. point out that urban livability research is an effective planning tool to help improve the quality of life of city residents (Wenzhong 2016). It can be seen that urban livability is a critical issue in urban construction and management, and is also the focus of resident’s daily lives (Guanhong and Jiaming 2018). The research on urban livability is an important content of the sustainable development research of urban environment, economy and society.

22.2 Study Area and Research Method 22.2.1 Overview of the Study Area Kunming City is selected as a case study for urban livability evaluation. Kunming, Yunnan Province, is located between 102°10' ~ 103°40' E and 24°23' ~ 26°22' N, on the Yunnan Guizhou Plateau, near the border of southwest China. Kunming is the political, economic and cultural centre of Yunnan Province, with a total area of about 21,000 km2 , a resident population of about 6,677,000 people/year at the end of the last five years and a total national economic value of about RMB 397 billion/ year in the last five years. Kunming’s livability should be a key concern due to its geographical importance. Kunming is a regional international centre city between China and Southeast Asia, South Asia and even the Middle East, Southern Europe and Africa. As a place attracting talents all over the world, Kunming is trying hard to become “the place for be”. Moreover, Kunming city actually inherits livability from

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its livable natural environment. The city is surrounded by mountains and bordered by the Dianchi Pond in the south, with an average annual temperature of around 15 °C. Typically, the winter is not too cold in Kunming and the summer is surprisingly cool compared to many other cities. Kunming’s unique geographical position has resulted in a high level of biodiversity. As the venue for the 15th Conference of the Parties to the Convention on Biological Diversity (COP15), Kunming has a natural advantage for livability studies.

22.2.2 Research Method This paper takes Kunming as a typical case and combines subjective and objective evaluations to study the livability of Kunming city. With reference to the five dimensions (i.e., safety, health, convenience, accessibility and comfort) of urban livability proposed by Zhang Wenzhong in the literature of “Exploring the connotation and evaluation index system of a livable city”, as well as relevant studies by other scholars, and combined with the characteristics of Kunming’s urban construction, following the principle of indicator screening (i.e., comprehensiveness and people-oriented principle, operability principle, regional principle), and studying the meaning of the indicators, we select and optimize indicators in five aspects: urban safety, environmental health, living convenience, travel convenience and living comfort to construct a subjective evaluation index system and an objective evaluation index system for the livability of Kunming city. For objective evaluation, we use the entropy method to determine the weight of indicators, and establish the evaluation model and calculate the overall score of livability of Kunming based on the composite index method; For the subjective evaluation, through the questionnaire survey, we collect relevant data of resident’s satisfaction to calculate the score of resident’s satisfaction. The results of the subjective evaluation are combined with the objective evaluation results to analyse the deficiencies in the livability of Kunming, and to put forward effective and constructive suggestions for building a livable city and improving the livability level of Kunming.

22.3 Data Sources The data for the objective indicators are mainly from the Kunming Yearbook and to a lesser extent from the Kunming Statistical Yearbook. Data on subjective indicators come from questionnaire survey data.

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22.4 Objective Evaluation Methods Establish an objective evaluation index system. Five primary indicators of urban safety, environmental health, convenience of living, travel convenience and residential comfort are selected, and several secondary indicators are determined under each primary indicator to build an objective evaluation index system of urban livability in Kunming. Determination of weights. The entropy method is used to determine the weights of objective indicators of urban livability in Kunming. This method can eliminate the overlap of information between multiple indicator variables and the interference of subjective ideas in human judgment of weights, and is widely used to evaluate the comprehensive level of urban livability (Jin 2011). (1)(1)(1)(1)(1) Establishing an initial data matrix of an objective indicator system to evaluate n indicators for m years in Kunming. { } X = xi j (0 < i ≤ m, 0 < j ≤ n)

(22.1)

x ij denotes the value of the j-th indicator for the i-th sample. (2) Data standardisation Because of the inconsistency of each indicator’s scale, unit and order of magnitude, they should be standardised first. Since the data after processing by the extreme value method takes values in the range of 0 to 1, and the existence of zero values has no practical significance for the evaluation by the entropy method, the data after the standardisation process is shifted to the right by 0.00005 units. Positive indicator treatment formula { } xi j − min x j ' { } + 0.00005 { } xi j = (22.2) max x j − min x j Negative indicator processing formula xi' j

{ } max x j − xi j { } { } + 0.00005 = max x j − min x j

(22.3)

max {x j } represents the maximum value of the j-th index, min {x j } represents the minimum value of the j-th index, x’ij represents the value of the normalised data shifted to the right by 0.00005 units. (3) Calculate the weight yij of the j-th indicator in the i-th sample yi j = xi' j /

m ∑ i=1

( ) xi' j 0 < yi j ≤ 1

(22.4)

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(4) Determine the information entropy value ej and information utility value d j of the indicator m )( ) 1 ∑( · Yi j · ln yi j 0 < e j ≤ 1 ej = − ln m i=1

(22.5)

dj = 1 − ej

(22.6)

If yij = 0, then use 0.00001 instead of calculating (Qingmei 2015), the larger d j is, the more important the indicator is for evaluating livability and the greater the weighting. (5) Calculation of weights dj w j = ∑n j=1

(22.7)

dj

wj is the weight of the j-th indicator. Construction of evaluation model. Individual indicator scores Z i j = xi' j w j

(22.8)

Combined livability score for the i-th sample Zi =

n ∑

Zi j

(22.9)

j=1

A higher composite score indicates a greater contribution to urban livability, while a lower composite score indicates a disincentive to urban livability (Yue 2018). Comprehensive score classification. In this paper, referring to the relevant domestic comprehensive score grouping method, a five-level grading standard is designed, and the corresponding grading is given (Table 22.1), and the comprehensive score of livable cities is further analyzed to determine the livability of the city. Table 22.1 Overall urban livability score scale

Level

Livability composite index (Z i )

Livability

Level 1

Z i > 0.80

Extremely high

Level 2

0.60 < Z i < 0.80

Very high

Level 3

0.40 < Z i < 0.60

High

Level 4

0.20 < Z i < 0.40

General

Level 5

Z i < 0.20

Relatively low

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Table 22.2 Resident’s satisfaction rating scale Grade

Completely Mostly Somewhat Neither Somewhat mostly Completely dissatisfied dissatisfied dissatisfied satisfied or satisfied satisfied satisfied dissatisfied

Assignment 1

2

3

4

5

6

7

Subjective evaluation methods. Five primary indicators of urban safety, environmental health, convenience of living, ease of travel and comfort of living were identified, and several secondary indicators were determined under each primary indicator to construct a subjective evaluation index system of urban livability in Kunming, design a questionnaire and conduct a questionnaire survey on resident’s satisfaction. Satisfaction was divided into seven levels, namely: Completely Dissatisfied, Mostly Dissatisfied, Somewhat Dissatisfied, Neither Satisfied or Dissatisfied, Somewhat Satisfied, Mostly Satisfied, Completely Satisfied, with values of 1, 2, 3, 4, 5, 6 and 7 respectively (Table 22.2). For each indicator, the numbers of times each option was selected are multiplied by the assigned value the corresponding assigned scales (i.e., 1 to 7), and then the products are summed up and divided by the total number of questionnaires to obtain the specific indicator satisfaction score, using the following formula: Z i = (Ai × 1 + Bi × 2 + Ci × 3 + Di × 4 + E i × 5 + Fi × 6 + G i × 7)/Ni (22.10) Z i is the satisfaction score of the i-th indicator, N i is the total number of questionnaires, Ai , Bi , C i , Di , E i , F i , Gi are the numbers of times of Completely Dissatisfied, Mostly Dissatisfied, Somewhat Dissatisfied, Neither Satisfied or Dissatisfied, Somewhat Satisfied, Mostly Satisfied, Completely Satisfied were selected for the i-th indicator option respectively.

22.5 Results and Analysis 22.5.1 Objective Evaluation Results and Analysis We select 5 first-lever indicators and 19 secondary indicators to construct an objective evaluation index system for the livability of Kunming (Table 22.3). The original data of 19 indicators of Kunming City from 2014 to 2018 were obtained by checking the yearbook (Table 22.4), and the information entropy value of each indicator was obtained by applying the formula of information entropy value, and then the information utility value was obtained, and the weights of each indicator of the objective evaluation index system of livability of Kunming City were calculated through the formula (Table 22.5), and the comprehensive scores of 5 primary indexes

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Table 22.3 Objective evaluation index system for urban livability in Kunming Primary indicators

Secondary indicators and codes

Unit

Properties

Urban safety

Incidence of criminal cases (A1)

Pieces/ 10,000 people

Negative

Incidence of traffic accidents Pieces/ 10,000 people (A2)

Negative

Travel convenience

Convenience of living

Environmental health

Density of urban road network (B1)

km/km2

Positive

Bus routes (B2)

Strip

Positive

Number of buses per 10,000 people (B3)

Vehicles/ 10,000 people

Positive

Parking spaces for 10,000 people (B4)

person/ 10,000 people

Positive

Length of road per capita (B5)

m/person

Positive

Net primary school enrolment (C1)

%

Positive

Net enrolment rate in junior secondary schools (C2)

%

Positive

Number of hospital beds per 10,000 population (C3)

Bed/ 10,000 people

Positive

Number of days with better than secondary air quality (D1)

Day

Positive

Industrial Solid Waste Disposal Utilisation Rate (D2)

%

Positive

Domestic waste disposal rate % (D3)

Positive

Sewage treatment rate (D4)

Residential comfort

%

Positive

Average urban noise decibels dB(A) (D5)

Negative

Number of library museums (E1)

number

Positive

Housing space per capita in urban areas (E2)

m2 /person

Positive

Green space coverage in built-up areas (E3)

%

Positive

Population density (E4)

Person/km2

Negative

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Table 22.4 Raw data by indicator, 2014–2018 Indicators and codes

2018

2017

2016

2015

2014

Incidence of criminal cases (A1)

116.79

134.16

173.90

170.29

134.22

Incidence of traffic accidents (A2)

2.44

2.23

2.56

2.41

2.56

Density of urban road network (B1)

0.121

0.855

0.853

0.838

0.836

Bus routes ( B2)

1158

1080

1137

892

869

Number of buses per 10,000 people (B3)

14.32

12.34

13.96

12.47

11.25

Parking spaces for 10,000 people (B4)

576.7

539.1

504.4

463.9

426.3

Length of road per capita (B5)

2.74

2.65

2.66

2.64

2.65

Net primary school enrolment (C1)

99.83

99.77

99.81

99.71

99.83

Net enrolment rate in junior secondary schools (C2)

98.6

97.28

96.34

95.36

96.86

Number of hospital beds per 10,000 population 92.26 (C3)

89.78

93.23

82.66

76.52

Number of days with better than secondary air quality (D1)

361

360

362

357

354

Industrial Solid Waste Disposal Utilisation Rate (D2)

99.82

95.35

99.36

99

98.16

Domestic waste disposal rate (D3)

99.68

100

98.9

95.53

91.93

Sewage treatment rate (D4)

97.13

94.59

94.43

94.36

94.1

Average urban noise decibels (D5)

54.4

53.2

53.5

53.5

53.8

Number of library museums (E1)

16

15

15

15

13

Housing space per capita in urban areas (E2)

43.58

43.96

43.76

42

40.71

Green space coverage in built-up areas (E3)

41.6

41.31

40.74

40.15

39.89

Population density (E4)

326

323

320

318

315

of objective evaluation of Kunming city livability are calculated according to the weights (Table 22.6). Figure 22.1 shows the change in the scores of the first-level indicators of urban livability in Kunming from 2014 to 2018. As can be seen from Table 22.6, the overall livability score of Kunming has been on an upward trend in the past five years, and the livability level has been improving year by year, and there is a big leap in the overall score from 2017 to 2018, with the livability level changing from “High” to “Extremely high”. This indicates that Kunming has made great progress in building a liveable city in 2018.

22.5.2 Subjective Evaluation Results and Analysis 35 secondary indicators were selected from five aspects: urban safety, environmental health, convenience of living, travel convenience and residential comfort, to build a subjective evaluation index system for urban livability in Kunming (Table 22.7).

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Table 22.5 Entropy values and weights for each indicator, 2014–2018 Indicators and codes

Entropy value Weights Total weights

Incidence of criminal cases (A1)

0.7299

0.0601

Incidence of traffic accidents (A2)

0.6196

0.0847

0.7403

0.0578

0.1448

Subtotal Density of urban road network (B1) Bus routes (B2)

0.7396

0.0580

Number of buses per 10,000 people (B3)

0.8025

0.0440

Parking spaces for 10,000 people (B4)

0.7968

0.0452

Length of road per capita (B5)

0.5564

0.0988

0.8410

0.0354

Subtotal

0.3038

Net primary school enrolment (C1) Net enrolment rate in junior secondary schools (C2)

0.8039

0.0437

Number of hospital beds per 10,000 population (C3)

0.8242

0.0391

Subtotal

0.1182

Number of days with better than secondary air quality 0.8284 (D1)

0.0382

0.8530

0.0327

Industrial Solid Waste Disposal Utilisation Rate (D2) Domestic waste disposal rate (D3)

0.8366

0.0364

Sewage treatment rate (D4)

0.5350

0.1035

Average urban noise decibels (D5)

0.8438

0.0348

0.7703

0.0511

0.2456

Subtotal Number of library museums (E1) Housing space per capita in urban areas (E2)

0.8303

0.0378

Green space coverage in built-up areas (E3)

0.7613

0.0531

Population density (E4)

0.7959

0.0454

Subtotal

0.1875

total

1

Table 22.6 Overall scores of objective evaluation of urban livability in Kunming, 2014–2018 Year Urban safety

Travel Convenience Environmental Residential Overall convenience of living comfort score health

Livability

2014 0.04179 0.00988

0.05561

0.03801

0.00001

0.14531 Relatively low

2015 0.04230 0.03817

0.01438

0.09313

0.05223

0.24022 General

2016 0.00001 0.17522

0.08185

0.13643

0.09942

0.49294 High

2017 0.12654 0.14592

0.07463

0.11639

0.13195

0.59543 High

2018 0.09094 0.30380

0.11734

0.20482

0.18299

0.89988 Extremely high

Scores of the Objective Evaluation of Primary Indicators

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0.3500 0.3000 0.2500 0.2000 0.1500 0.1000 0.0500 0.0000 2014

2015

2016

2017

2018

Year Urban safety Convenience of living Residential comfort

Travel convenience Environmental health

Fig. 22.1 Change in primary indicators scores of the objective evaluation of urban livability in Kunming, 2014–2018

Questionnaires were distributed to investigate resident’s satisfaction with the 35 secondary indicators mentioned above. The questionnaire was structured in three main sections: (1) basic information about Kunming residents; (2) resident’s satisfaction with five aspects of the city: urban safety, environmental health, convenience of living, travel convenience and residential comfort; and (3) suggestions for improving the livability of Kunming city. The questionnaires were distributed in the form of online questionnaires and 314 were actually returned. The secondary indicator scores and the satisfaction scores for each primary indicator as well as the overall satisfaction score for the livability of Kunming city were calculated from Eq. (22.10) (Table 22.8). From Fig. 22.2 and Table 22.8, it can be seen that the overall score of livability satisfaction of residents in Kunming city is 4.35, which is between Neither Satisfied or Dissatisfied and Somewhat Satisfied. The top five indexes, from high to low, are: convenience of living, environmental health, residential comfort, urban safety and travel convenience, while the scores of urban safety and travel convenience are lower than the overall resident’s satisfaction score. We need to strengthen urban safety and travel convenience. The six secondary indicators of travel convenience and urban safety (i.e. ease of access to the city centre from one’s residence, ease of parking, urban roads, smooth traffic flow, traffic safety and shelter coverage), which the scores of satisfaction levels are below 4, with satisfaction levels ranging from Somewhat Dissatisfied to Neither Satisfied or Dissatisfied, while five of the six secondary indicators are related to urban transport. Therefore, the level of urban transport in Kunming needs to be further strengthened in order to improve resident’s satisfaction.

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Table 22.7 Subjective evaluation index system for urban livability in Kunming Primary indicators

Secondary indicators

Urban safety

Ability to handle emergencies Law and order situation Level of access to safety education Public health safety measures Shelter coverage Traffic safety

Environmental health

Water quality Air Quality Noise pollution Waste disposal Industrial pollution control Urban sanitation and hygiene

Convenience of living

Catering situation Status of educational facilities Condition of public equipment Condition of amusement equipment Condition of the daily shop Status of medical equipment Courier penetration Popularity of takeaway Public facilities management

Travel convenience

Popularity of public transport Traffic flow Urban road conditions Convenience of parking Ease of commuting Convenience of living and travelling Ease of access to the city centre from the residence

Residential comfort

Human landscape Natural landscapes City management Greenery Property management Area of public land Building density

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Table 22.8 Satisfaction scores for urban livability in Kunming Number Urban Environmental Convenience Travel Residential Overall of safety health of convenience comfort rating samples Living Values 314 and scores

4.08

4.48

4.67

4.00

4.40

4.35

Building density Area of public land Property Management Greenery City Management Natural landscapes Human landscape Ease of access to the city centre from the… Convenience of living and travelling Ease of commuting Convenience of parking Urban road conditions Traffic flow Popularity of public transport Public Facilities Management Popularity of takeaway Courier penetration Status of medical equipment Condition of the daily shop Condition of amusement equipment Condition of public equipment Status of educational facilities Catering situation Urban sanitation and hygiene Industrial pollution control Waste disposal Noise pollution Air Quality Water quality Traffic Safety Shelter coverage Public health safety measures Level of access to safety education Law and order situation Ability to handle emergencies 0

1

2

3

4

5

6

Fig. 22.2 Satisfaction scores for each secondary indicator

22.6 Conclusions and Suggestions 22.6.1 Conclusions After comprehensive analysis the results of objective evaluation and subjective evaluation, the following conclusions are drawn:

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(1) The results show that in recent 5 years, the comprehensive score of objective evaluation of urban livability in Kunming has an increasing trend, and the degree of constructed livability increases year by year. The overall score of livability satisfaction of residents in Kunming city is 4.35, which is between Neither Satisfied or Dissatisfied and Somewhat Satisfied. (2) The top five indexes, from high to low, are: convenience of living, environmental health, residential comfort, urban safety and travel convenience, while the scores of urban safety and travel convenience are lower than the overall resident’s satisfaction score. (3) The six secondary indicators of travel convenience and urban safety (i.e. ease of access to the city centre from one’s residence, ease of parking, urban roads, smooth traffic flow, traffic safety and shelter coverage), which the scores of satisfaction levels are below 4, with satisfaction levels ranging from Somewhat Dissatisfied to Neither Satisfied or Dissatisfied.

22.6.2 Suggestions This paper comprehensively analyzes the subjective and objective city livability evaluation results and puts forward feasible suggestions to improve livability construction in Kunming are as follows, this will help to keep sustainable development of urban environment, economy and society. Strengthening urban roads. The following measures should be taken in Kunming’s traffic development: (1) widening lanes; (2) increasing the density of the road network; (3) building subways or overpasses to divert traffic on congested roads that cannot be widened; (4) installing one or more expressways throughout the city, similar to a highway over the city; (5) accelerating the construction of urban railways; (6) building car parks and temporary parking spaces. Increase investment in education and healthcare. The number of primary and secondary schools should be increased appropriately, and in the process, the availability of teaching equipment and teachers should be ensured. In terms of health care, it is important to increase the number of hospital beds and rural medical facilities, and to expand health insurance coverage to ensure that all residents have access to treatment for their illnesses. Improving urban safety. Improving the safety of a city is the most basic guarantee of personal security for its residents. In this study, it is clear that residents are below average in their satisfaction with this aspect. Therefore, the government of Kunming should do its best to do the following: (1) to improve the emergency shelter capacity of Kunming and build shelters that match the level of population concentration; (2) to strengthen the resident’s ability to deal with danger and raise their awareness of disaster prevention and mitigation; (3) to strengthen the traffic safety and security system in Kunming and improve the system for preventing traffic accidents; (4) to strengthen community security management and improve the ability of residents to prevent fraud and the ability to protect themselves in the face of criminal incidents.

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Author Contributions: The seven co-authors together contributed to the completion of this article. Junmei Li was the first author on writing-original draft preparation, writing-review, and submission process; Qing Hui, Runqiu Fei, Jinyu Liu, Ruixue He, Jing Zhou contributed to data analysis, the results, and conclusion; Guoqi Qian acted as corresponding author on their behalf throughout writing-review, editing. All authors have read and agreed to the published version of the manuscript. Funding: This study was funded by Yunnan Philosophy and Social Science Research Base Projects (JD2019YB05 and 2018DG005); The program of Yunnan Provincial government-sponsored study abroad in 2019 (File No. 2019003). Declarations Conflict of Interest: The authors declare that they have no conflict of interest.

References Guanhong W, Jiaming Z (2018) Evaluation of urban livability in Huaihai Economic Zone based on entropy value weighting method. J Hunan City College (natural Science Edition) 27(03):42–45 Jin L (2011) Study on the measurement and evaluation of urban livability in Zhejiang Province. Chongqing University of Technology and Industry Liping L (2001) Urban habitat. China Light Industry Press, Beijing, pp 45–49 Lixin L (2016) Interpretation and application of the idea of idyllic city in the new period. Shanxi Architect 42(21):35–36 Qingmei L (2015) Research on the evaluation and countermeasures of ecological civilization construction in Shandong Province. Shandong Normal University Wangwu L, Xinyue Y et al (2000) A review of the development of theory and practice of habitat environment in China and abroad. J Zhejiang Univer (science Edition) 27(2):205–211 Wenzhong Z (2016) Theoretical research and practical considerations on the construction of livable cities in China. Int Urban Plann 31(05):1–6 Xid X, Hao W, Xiang L (2017) Urban liveability in Melbourne. Shanghai Urban Plann 05:90– 93+105 Xianpeng W (2012) A review of domestic livable city evaluation studies. Housing Industry 09:47–50 Xuan Z, Hui Z (2018) Study on the evaluation of urban livability of small towns in western ChinaJinning District, Yunnan Province as an example. Ecol Cities and Green Build 03:70–77 Yue G (2018) Research on the evaluation of urban livability in Hohhot. Inner Mongolia Normal University

Chapter 23

Water Level Monitoring Sensor Based on Iontronic Piezo-Capacitance Effect Changbao Xu , Xiaobo Pu, Jiahao Fang, Tingting Yang , and Mingyong Xin

Abstract With the advancement of urbanization and the rapid development of the electric power industry, the safe operation of the electric power grid has become more and more important. Most cable trenches in cities are built underground, and under the harsh environment of heavy rainfall and flooding, rainwater will flow into the wells. The large amount of water in the cable trench can lead to cable shortcircuit, cause cable burst and other problems, and damage the normal operation of the power grid. Therefore, real-time monitoring of water levels in cable trenches and substations is crucial to protect them from the threat of flooding. This paper introduces an iontronic pressure sensor for the water level surveillance in cable trenches and substations. The sensor is a double electric layer (EDL) based capacitive pressure sensor and has a minimum pressure monitoring value of 25 Pa and a sensitivity of S = 0.85 kPa−1 within the range of 0–450 kPa. It also has a quick response time of 822 ms for applied pressure and 424 ms for removed pressure. Additionally, it has shown stability for 2000 cycles of compression and release. We use the sensor for water level monitoring. The sensor can monitor different water levels very well and the sensor responds quickly and steadily even if the water level changes by only 1 cm. Keywords Water level monitoring · Iontronic · Double electric layer · Capacitive pressure sensor

C. Xu · M. Xin Electric Power Research Institute of Guizhou Power Grid Company Limited, Guiyang 550002, P.R. China X. Pu · J. Fang · T. Yang (B) Tribology Research Institute, School of Mechanical Engineering, Southwest Jiaotong University, Chengdu 610031, P.R. China e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_23

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23.1 Introduction The city’s cable trenches are basically buried under the roadway, and a cable well will be set up at intervals in the cable trench, but the cable well is not built to be waterproof. During heavy rainfall and flooding, this can lead to a large amount of water in the cable passageway. If the water level reaches the height of the cable, the cable in the cable trench will be immersed in water for a long time, even if the cable laying with waterproof tape wrapped around the cable head, can prevent part of the water corrosion of the cable, but also easy to cause cable burns, cable short-circuit, cause cable burst and other problems, damage the power grid normal operation. Therefore, it is crucially important to strengthen the monitoring of the water level in the cable trench and substation and to drain the water in time. Since the pressure of different water levels is different, we can monitor the water level of cable trench and substation in real time by using pressure sensors. Pressure sensors are ubiquitous in our daily lives and play a vital role in various fields, from automobiles to structural health monitoring in civil structures (Sikarwar 2017) and biomechanical applications (Xu et al. 2018; Leal-Junior et al. 2021). It is also importance for environmental surveillance, especially for water level monitoring (Hooke 1979). According to the measurement principle, we can classify pressure sensors into optical signal sensing and electrical signal sensing (Lee 2003). Optical signal pressure sensors utilize optical signals to convert external pressure into a variation of light beam wavelength (Wagner et al. 1993; Wang et al. 2006, 2009; Brabander et al. 1998; Datchi et al. 1997). Over the past few decades, fiber optic pressure sensors have solved many environmental pressure sensing challenges (Schenato 2017; Shanafield et al. 2018; Riza et al. 2020; Vorathin et al. 2020). Electrical signal pressure sensors are capable of converting external pressure into electrical signal readings. These sensors can be classified into four types: capacitive sensors, resistive sensors, piezoelectric sensors, and frictional sensors. Compared to optical signal pressure sensors, electrical signal pressure sensors possess simple structure and easy implementation of direct signal conversion. Therefore, pressure sensors, especially capacitance-based pressure sensors, have been extensively developed and applied. The principle of capacitive pressure sensor is based on the fact that the distance between two electrode plates decreases under pressure load, exhibiting an increase in capacitance thus enabling pressure monitoring. However, the capacitance of ordinary capacitive pressure sensors is limited to pF cm−2 because the spacing between the two electrodes of ordinary capacitors and the dielectric constant of the middle layer are finite. This limitation leads to low sensor sensitivity and susceptibility to parasitic effects and electromagnetic noise. (Park et al. 2014; Mannsfeld et al. 2010; Zhou et al. 2017) In 2011, Pan proposed a pressure sensing approach called iontronic pressure sensing which utilizes the EDL super-capacitance properties between the elastic dielectric layer and the electrode plate (Nie et al. 2012). These sensors have an incredibly high unit area capacitance of a few µF cm−2 , which is 106 times higher than the capacitance of ordinary capacitive pressure sensors. Consequently, iontronic

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capacitive pressure sensors have ultra-low monitoring pressure limits and ultra-high sensitivity. (Lei et al. 2012; Lipomi et al. 2011; Sergio et al. 2002; Woo et al. 2014). Here, an iontronic capacitive sensor is designed to monitor the water level of real-time in cable trench and substation. This pressure sensor is based on the EDL super-capacitance property between the elastic electrolyte and the electrode plate. The sensor is composed of a three-layer structure, with an ionic gel film in the middle layer and flexible electrodes on the top and bottom layers. Our iontronic capacitive sensors exhibit ultra-high sensitivity (0–450 kPa, S = 0.85 kPa−1 ), a quick response time of 822 ms for applied pressure and 424 ms for removed pressure, and a minimum pressure monitoring value of 25 Pa. The sensor also exhibits excellent mechanical stability, with 2000 compression/release cycles at 150 kPa high pressure and the sensor still exhibits high stability. Our sensors can also respond quickly and consistently to changes in water depth of 1 cm.

23.2 Materials and Methods 23.2.1 Finite Element Analysis For the simulation of the sensor, we used the ABAQUS 6.14 commercial software package to simulate the sensor deformation under pressure. We determined the Young’s modulus of the PVA/H3O4 ionic gel film to be approximately 2.5 MPa based on experimental measurements. The PET-Au electrodes were set up as structural steel with a Young’s modulus of about 210 GPa.

23.2.2 Preparation of PVA Ionic Gels In this experiment, 1 g of PVA was added to 9 g of DI water stirring for 1 h at a speed of 300 r/min in the temperature of 90 °C until the PVA was fully dispersed and dissolved. The gel solution was then cooled and H3 PO4 was added, which was continuously stirred for another hour. To prepare ionic gels with different ionic concentrations, we added different proportions of H3 PO4 , and the ionic gels were formulated as in Table 23.1. Finally, the mixed ionic gel solution was poured on sandpaper and cured vacuum drying oven at 40 °C for 3 h. After curing, the ionic gel films were easily torn off to obtain ionic gel films with sandpaper surface microstructures. To prepare ionic gels with different surface microstructures, commercial sandpaper with different roughness (roughness of 1500, 4000, 6000, 10,000 #) was used as a template.

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PVA

Deionized water (g)

H3 PO4 (ml)

1g

9

0.2

1g

9

0.4

1g

9

0.8

1g

9

1.2

23.2.3 Preparation of Electrodes and Sensors In order to create flexible electrodes, a flexible polyethylene terephthalate film (PET, 50 µm thickness) was cleaned and treated with oxygen plasma (MIT Corporation PCE-6). A layer of gold (50 nm) was then deposited onto the PET surface using a vacuum coater (EM ACE200). The flexible electrode was cut to size (10 × 10 mm) using a laser cutter (FAT-15) and conductive copper tape was attached to one corner of the flexible electrode. To complete the sensor fabrication, an ionic gel film was placed between the two electrodes and then encapsulated with PI tape.

23.2.4 Characterization and Measurements The sensor was mounted on a tensioning machine (AGS-S) with a computer console, that can be used to apply pressure to the sensor and record the pressure level. We used tensioning machine to measure the sensor’s sensitivity and cyclic stability. In order to measure the capacitance value, we connected the lead of the sensor to an LCR meter (TH2832, THW). The voltage and frequency of the LCR meter were set to 0.5 V and 1 kHz respectively. In addition, when measuring the response time, we set the frequency to 10 kHz. To characterize the surface morphology of the ionic gel films, a field-emission scanning electron microscope (FE-SEM, JSM-6700F, JEOL) was utilized.

23.3 Results and Discussion 23.3.1 Structure and Principle of Iontronic Pressure Sensor The iontronic capacitive pressure sensor, depicted in Fig. 23.1, is composed of a three-layer structure with a deformable solid ionic gel film in the middle layer and flexible PET-Au electrodes at the top and bottom. An EDL capacitance is formed at the meeting place where the electrodes are in contact with the ionic gel film, and the iontronic pressure sensor operates according to the change in EDL capacitance. The value of our sensor capacitance can be thought of as two EDL capacitance values in

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Fig. 23.1 Schematic diagram of the structure of the iontronic capacitance pressure sensor

series. The capacitance of the whole device (C) can be calculated using the formula 1/C = 1/C EDL1 + 1/C EDL2 . Generally, the capacitance (C) is related to the contact area between the dielectric layer and the electrodes (S), the dielectric constant (ε), and the spacing between the two electrode plates (d). The EDL capacitance is large due to the aggregation of electrons on the EDL capacitor electrodes and counter ions in the electrolyte at nanometer distances in the contact area. Therefore, the dielectric constant (ε) and the spacing (d) have basically no effect on the EDL capacitance only the contact surface (S) has a great influence on the EDL capacitance. For iontronic capacitive pressure sensors, the microstructure of the ionic gel film surface has a great influence on the sensitivity of the sensor. The microstructure initially has irregular and unequal structural specialties, resulting in very few contact points with the electrodes. As a result, the interface between the ionic gel film surface and the electrode produces only a small EDL capacitance. When pressure is applied, the contact area between the ionic gel film surface and the electrode increases, leading to a significant increase in the EDL capacitance. For our sensor, the microstructure is present on one surface of the ionic gel, while the other surface is smooth. Therefore, only the contact surface between the upper electrode and the ionic gel film changes, so C EDL2 is constant and the overall capacitance C is determined by C EDL1 . When pressure is applied to the iontronic capacitive pressure sensor, C EDL1 changes and the overall capacitance C changes, thus enabling the monitoring of the pressure.

23.3.2 Effect of Ion Concentration on Sensor Sensitivity To investigate the impact of ion content in ionic gels on the performance of iontronic pressure sensors. We added varying amounts of H3 PO4 (0.2, 0.4, 0.8 and 1.2 ml) to 10 g of gel and measured the sensor”s sensitivity with different ion contents. The results, as shown in Fig. 23.2a, indicate that the sensor’s sensitivity increases with increasing ion content and reaches its peak at 0.4 ml/g. However, beyond this point, the sensitivity of the sensor decreases with increasing ion content. Figure 23.2b illustrates the change in capacitance of the sensor with pressure at different ion concentrations. We observed that while the change in capacitance of the sensing

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Fig. 23.2 Effect of ion concentration on sensing performance. a Variation of sensitivity of the sensor at different H3 PO4 content. b Variation of capacitance value of the sensor at different H3 PO4 content

increases with increasing ion concentration, the initial capacitance also increases with increasing ion concentration. Therefore, the variation of the sensitivity of the sensor at different H3 PO4 content is influenced by both the final and initial capacitance. The content of ions in the gel plays a crucial role in determining the sensor’s sensitivity. Low ion concentrations lead to insufficient ions moving to the electrode surface to form an electrical double layer (EDL), resulting in low initial and final capacitance values. This results in a small change in the multiples of capacitance and consequently, a low sensitivity. Conversely, high ion concentrations lead to a large initial capacitance as many ions have already moved to the surface of the gel to form the EDL. When we apply pressure to the sensor, the multiples of capacitance will be change small due to the excess ions already present on the surface. The sensitivity will also be greatly reduced. Thus, the sensitivity of the sensor at low ion concentrations is affected by the final capacitance being too small, while at high ion concentrations the sensor sensitivity is affected by the initial capacitance being too large.

23.3.3 Effect of Microstructure on Sensing Performance Differences in microstructure of ionic gels can lead to differences in sensing performance between sensors. Scanning electron microscopy (SEM) reveals that sandpaper with varying grit sizes results in microstructures of varying sizes. For instance, 10,000 mesh sandpaper prepared ionic gels have microstructures of approximately 1 µm, while 1500 grit sandpaper prepared ionic gels have microstructures of approximately 30 µm. As such, a larger sandpaper mesh results in smaller surface microstructures and higher density. The results presented in Fig. 23.3a indicate that the sensitivity of the sensor is directly proportional to the density of the microstructure. Additionally, Fig. 23.3b shows that the initial capacitance of the sensors with different microstructures are similar but the final capacitance increase as the density of the

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microstructure increases. Therefore, the trend of the sensitivity of the sensor under different microstructures may be due to the different changes of the contact surface between the ionic gel film and the electrodes. In order to demonstrate the effect of microstructure on sensor performance, we conducted finite element simulation analysis for different microstructure ionic gels, as shown in Fig. 23.3c. The simulation analysis revealed that the larger the number of sandpaper mesh, the contact surface of the electrode and ionic gel film changed more under the same pressure, resulting in a larger change in capacitance and ultimately leading to higher sensor sensitivity.

23.3.4 Effect of Ionic Gel Thickness on Sensing Performance To investigate the impact of ionic gel thickness on sensing performance, we prepared ionic gels of varying thicknesses (100, 200, 400 and 600 µm) by adjusting the amount of ionic gel cast onto the template. Our results show that as the thickness of the ionic gel film increases, the sensitivity of the sensor decreases, as illustrated in Fig. 23.4a. To explore the reasons behind this phenomenon, we conducted a pressure simulation analysis on ionic gels of varying thicknesses. The results, depicted in Fig. 23.4b, demonstrate that as the thickness of the ionic gel increases, the deformation is less readily transferred to the microstructure. This, in turn, makes it more challenging to alter the contact area between the electrolyte film and electrode, ultimately decreasing the sensor’s sensitivity.

23.3.5 Sensing Characteristics of Iontronic Pressure Sensor Figure 23.5a depicts the iontronic pressure sensor’s sensitivity after parameter optimization, displaying high linearity within the 0–450 kPa range and a sensor sensitivity of 0.85 kPa−1 . Figure 23.5b illustrates the response time for applying/removing pressure, which is approximately 822 ms/424 ms. The iontronic pressure sensor has a minimum pressure monitoring value of 25 Pa, as shown in Fig. 23.5c. Additionally, we investigated the cycling stability of the iontronic pressure sensor, and Fig. 23.5d shows that the sensor maintains high stability even after 2000 cycles at 150 kPa, indicating the high repeatability of our iontronic capacitive pressure sensor.

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Fig. 23.3 Effect of microstructure on sensing performance. a Variation of sensitivity of the sensors under different microstructures. b Variation of capacitance value of sensors under different microstructures. c Pressure simulation of ionic gel with different microstructures

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Fig. 23.4 Effect of different thicknesses on sensing performance. a Variation of sensor sensitivity at different ionic gel thicknesses. b Pressure simulation of ionic gel with different thicknesses

23.3.6 Iontronic Pressure Sensor for Water Level Monitoring In order to monitor different water levels, we set five different depths of 0, 20, 23, 25 and 26 cm. As shown in Fig. 23.6a, we attached the sensor to the bottom wall of a cylindrical glass with a depth of about 30 cm, connected the sensor wires to the test equipment, and then poured water at 20, 23, 25 and 26 cm depths into the glass in turn. Figure 23.6b shows the variation of sensor capacitance readings at different depths, from which it can be seen that the sensor can monitor different water levels very well, and the response is fast and the response signal is stable. Even at 1 cm of water level change, the sensor can respond quickly.

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Fig. 23.5 Sensing performance of the sensor. a Capacitance value and sensitivity of the sensor. b Chattering/response time of the sensor. c The minimum monitoring limit of the sensor. d Cycling stability of the sensor

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Fig. 23.6 Iontronic capacitive sensor measuring water level. a Schematic diagram of different water depths. b Response of the sensor to different water depths

23.4 Conclusion Real-time monitoring of the water level in cable trenches and substations to avoid the threat of flooding is important for the safe operation of the power grid. In this paper, an iontronic capacitive pressure sensor is introduced to monitor the water level in cable trench and substation. We investigated the effects of different types of ionic gel films on the sensor performance, including ion concentration, microstructure density, and film thickness. After optimization of the iontronic capacitive pressure sensor performance, the sensor has an ultra-high sensitivity (0–450 kPa, S = 0.85 kPa−1 ), a minimum pressure monitoring value of 25 Pa, an applied/removed pressure response time of 822 ms/424 ms, and 2000 cycles of compression/release stability. We applied the sensor to water level monitoring and the sensor was able to monitor different water levels very well, even if only 1 cm of water level change, the sensor was able to monitor it quickly and stably.

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Wang W, Wu N, Tian Y, Wang X, Niezrecki C, Chen J (2009) Optical pressure/acoustic sensor with precise Fabry-Perot cavity length control using angle polished fiber. Opt Expr 17:16613. https:// doi.org/10.1364/OE.17.016613 Woo S-J, Kong J-H, Kim D-G, Kim J-M (2014) A thin all-elastomeric capacitive pressure sensor array based on micro-contact printed elastic conductors. J Mater Chem C 2:4415–4422. https:// doi.org/10.1039/C4TC00392F Xu F, Li X, Shi Y, Li L, Wang W, He L, Liu R (2018) Recent developments for flexible pressure sensors: a review. Micromachines 9:580. https://doi.org/10.3390/mi9110580 Zhou Y, He J, Wang H, Qi K, Nan N, You X, Shao W, Wang L, Ding B, Cui S (2017) Highly sensitive, self-powered and wearable electronic skin based on pressure-sensitive nanofiber woven fabric sensor. Sci Rep 7:12949. https://doi.org/10.1038/s41598-017-13281-8

Chapter 24

Research on the Implementation Path of Landscape Dispatch of Irrigated Reservoir Bin Liu and Huajian Fang

Abstract The demand for reservoir landscape tourism is becoming increasingly important. However, there is relatively little research on landscape scheduling for many irrigated reservoirs. In this case, this study attempts to use objective programming, long series hydrological and water resource data, to increase the water source of irrigated reservoirs by comparing and analyzing the effects of reservoir selfregulation and adjacent water diversion measures. The study shows that the effect of the cross-basin water diversion project is poor, and increasing the normal water level of the reservoir and moving up the required capacity for irrigation can meet the needs of irrigation and eco-logical landscape. Through the empirical analysis, it can reduce the construction of water diversion project from the adjacent river basin and verify the effectiveness of improving the reservoir self-regulation by increasing normal water storage level, which provides a reference for decision-making of the reservoir construction for the existing functional adjustment. Keywords Reservoir landscape dispatch · Water diversion from adjacent areas · Supply and demand balance · Long series data · Objective programming

24.1 Introduction Many studies have pointed out that water resources projects provide opportunities for landscape function, such as field tourism and cultural activity (Liu et al. 2021; Acreman et al. 2011; Wang et al. 2006; Turpie and Joubert 2001). Lagarense and Walansendow (2015), and other scholars (Hoyle 2002; Gospodini 2001) studied the development of waterfront tourism; Mazvimavi et al. (2010) and others (Nelson B. Liu (B) Department of Engineering Management, School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha 410004, China e-mail: [email protected] H. Fang Zhejiang Zhefeng Engineering Consulting Co.,Ltd, Hangzhou 310021, China © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_24

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et al. 2000; Miller 1993) explored marine beach water tourism. Mereu has studied the operational resilience of reservoirs to climate change, agricultural demand, and tourism (2015). Demertzi used the WEAP (Water Evaluation and Planning) model to assess the impact of rural and seasonal tourism activities plus drought on reservoir operation in semi-arid Greece (2014). Since the reservoir has the characteristics of good water quality and excellent ecological environment, it can be predicted that the ecological landscape demand for reservoir scenic tourism will increase in the future, and the original goals of the reservoirs will continue to change. Because the reservoirs have irrigation, flood control, power generation, and other projects, the addition of the ecological landscape task will inevitably affect the realization of these objectives. How to make full use of engineering measures such as developing the water source and controlling water use, giving full play to reservoir regulation and storage, is the key point of built reservoirs for landscape dispatch optimization. This has attracted the attention of many experts and scholars and achieved many research results on the premise of meeting the constraints of river ecological water demand and flood control. Tarebari s’ research has found that the amount of available resources or reservoir volume plays an important role in optimizing reservoir operation, meaning that the higher the amount of water resources or the larger the reservoir, the easier it is to achieve reservoir operation optimization (2018). Liu et al. (2019) believes that there are two available ways to increase the water source of multi-functional reservoirs for the new demand of reservoir ecological landscape dispatching, i.e., improving the reservoir’s own water storage capacity, and water diversion from external areas. Raju and Pillai (2007) compare and analyze eight alternative multi reservoir joint operation schemes based on six uncontrollable discrete criteria, namely irrigation, power generation, drinking water supply, environmental quality, flood control, and benefiting from projects, in order to scientifically address watershed planning issues. Wan et al. derives a multi reservoir optimal operation model based on cross basin water transfer (2017). However, there is relatively little research on landscape scheduling of irrigated reservoirs. To this end, this study focuses on the implementation path of landscape scheduling for irrigated reservoirs based on reservoir self-regulation and adjacent water diversion measures. This paper is organized as follows. Section 24.1 introduces the research background including the research gap and the idea of this study. Section 24.2 presents the methodology. Section 24.3 conducts the empirical study on the research method combined with a landscape dispatch case of irrigated reservoir. Sections 24.4 gives a result analysis and discussion to obtain the main research findings. The conclusions are drawn in Sect. 24.5.

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24.2 Research Methods 24.2.1 Objective Function The objective of landscape dispatch of irrigated reservoir is to maximize the landscape limit water level or storage capacity under the constraints of the existing functions of the reservoir. ) ( V0 = Max Vzc − V p or Z 0 = For ecast(V0 , Z ∼ V )

(24.1)

In the formula: V 0 , V zc , V p and Z 0 are the landscape limit capacity for irrigation (10,000 m3 ), normal capacity (10,000 m3 ), utilizable capacity (10,000 m3 ), and landscape limit water level (m); Z ~ V is the relationship curve between the water level and capacity of reservoir. Same below.

24.2.2 Constraints There are some constraints in the landscape regulation of irrigation reservoirs, mainly including the water balance law of the reservoir itself, external water diversion constraints, and the constraints of the existing functions of the reservoir. (1) Water balance law of the reservoir. The water balance mainly considers the balance relationship between changes in reservoir capacity and incoming and outgoing water, as detailed in formula 24.2. In addition, the irrigation flow of an irrigated reservoir depends on the irrigation water demand and the available water supply of the reservoir, which can be represented as the smaller value between them by formula 24.3. The amount of abandoned water depends on the capacity of the utilizable capacity, and only the portion exceeding the utilizable capacity will be abandoned, which can be represented by formula 24.4. ) ( Vt+1 = Vt + Q jt + α × qt − Q lt − Q et − Q gt − Q xt ∆t × 8.64 × dt (24.2) Q gt × ∆t × 8.64 × dt ) ) ( ( = min Vt - 1 + Q jt + α × qt − Q lt ∆t × 8.64 × dt , Wgt

(24.3)

Q xt × ∆t × 8.64 × dt ) ( ) ( Vt - 1 + Q jt + α × qt − Q lt × ∆t × 8.64 × dt > V p , ( ) (24.4) = IF Vt - 1 + Q jt + α × qt − Q lt − Q gt × ∆t × 8.64 × dt , 0

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In the formula: V t+1 , V t , Qjt , qt , Qlt , Qet , Qgt , Qxt , d t , and W gt are the final capacity (10,000m3 ), initial capacity(10,000 m3 ), incoming water flow (m3 /s), diversion flow (m3 /s), loss flow (m3 /s), ecological flow (m3 /s), irrigation flow (m3 /s), abandoned water flow (m3 /s), days of the t period, and irrigation gross water demand of the reservoir in day t (10,000m3 ) respectively; ∆t is the number of ten-day in the t period; α = 1 when using a diversion scheme, and α = 0 when using a non-diversion scheme. (2) External water diversion constraints. The external water diversion flow depends on the available diversion flow and maximum water diversion capacity of the diversion tunnel, which can be represented as the smaller value between them by formula 24.5. According to the water balance law, the available diversion flow should be deducted from the water production flow in the diversion area, including the loss flow, ecological flow, and the production and domestic water consumption in the downstream of the diversion channel. qt ≤ min(Yt , qlim t )

(24.5)

Yt = qht −qlt − qet − qst

(24.6)

In the formula: qt , Y t , qlimt , qht , qlt , qet , and qst are the external water diversion flow in t period (m3 /s), available diversion flow (m3 /s), the maximum water diversion capacity of the diversion tunnel (m3 /s), the water production flow in the diversion area (m3 /s), loss flow (m3 /s), ecological flow (m3 /s), and the production and domestic water consumption in the downstream of the diversion channel (m3 /s). (3) The constraints of the existing functions of the reservoir. Irrigated reservoirs usually include flood control, ecology, and irrigation functions. The flood control function requires that the normal water storage level after landscape adjustment cannot exceed the flood control limit water level by formula 24.7; the ecological function requires that the ecological flow can meet the water demand of the downstream ecosystem, as detailed in formula 24.8; and the irrigation function requires that the irrigation guarantee rate of the reservoir after landscape adjustment meet the specification requirements by formula 24.9. Z ct ≤ Z lim ct

(24.7)

Q et ≥ γ Q jt

(24.8)

qet ≥ γ qht

(24.9)

P≥P

(24.10)

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In the formula: Z ct , γ , P, and P are the normal water storage level (m3 /s), the ecological base flow coefficient calculated according to the Tennant method (1976) (taking 10% of the average multi-year runoff of the dam site), the irrigation guarantee rate and its control value (85% according to the specification (Ministry of Housing and Urban Rural Development of the People’s Republic of China 2018)) respectively.

24.2.3 Model Solving The calculation of reservoir runoff regulation generally adopts a long series of monthly or ten-day adjustment calculations, and this time a long series of data is used for calculation. According to the objective function and constraints, the irrigation guarantee rate is solved by trial calculation based on utilizable capacity. The iteration process is as follows: (1) Assuming that the utilizable reservoir capacity is V p1 , this study calculates the reservoir final reservoir capacity V t+1 and the irrigation water shortage (W gt −Qgt × ∆t × 8.64 × d t ) through the formulas 24.2, 24.3 and 24.4, and defines the statistical water shortage year according to the irrigation guarantee rate P. (2) If the water shortage year > n × (1–85%), it will increase, and vice versa, it will decrease, and return to step (1) to calculate the water balance. (3) If the water shortage year = n × (1–85%), exit the iteration and the calculation is completed.

24.3 Case Study 24.3.1 Study Area The reservoir in this case study is a medium-sized reservoir, has a normal storage capacity of 25.6 million m3 for the irrigation function with an original designed irrigation area 51,000 mu. With the development of urban construction, the irrigation area has shrunk to 36,300 mu, mainly because urban construction occupies part of the cultivated land, but the requirements for ecological landscape have increased and are very urgent. The function of the reservoir will be changed to focus on irrigation and ecological landscape: that is, under the premise of satisfying the irrigation water and not raising the dam, the irrigation stagnant water level will be raised as much as possible to reduce the drawdown zone. At present, the reservoir is dry from October to April of the following year, the driest water level is 58.78 m, the reservoir area has a drawdown zone of nearly 17 m, and the drawdown zone of the reservoir tail stretching for more than 5 km shows a loess color, which is in sharp contrast with the landscape when the water level is high, which has a great adverse impact on the ecology of the

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Fig. 24.1 Route diagram of water diversion scheme

reservoir area, and does not meet the ecological landscape requirements of regional development for the reservoir, as shown in Fig. 24.1. In order to meet the increased landscape function of the irrigated reservoir, this study considered whether water can be diverted from the nearby watershed and analyzed the effect of water diversion. According to the trend of the river system around the reservoir area, topographic and geomorphological conditions, regional construction planning, surrounding social and economic development, the preliminary water diversion plan is as shown in Fig. 24.1, and the specific content of the water diversion plan is as follows: Water source point 1, build a dam to store water in a nearby tributary of the adjacent river basin, and transmit water to the end of the reservoir through the tunnel, the length of the tunnel is 4.5 km, and the rainfall collection area above the dam site is 4.3 km2 . Water source point 2, build a dam to store water in a place near the tributary of the adjacent river basin, build a tunnel + channel along the line for a total of 9.81 km to intercept water to the end of the reservoir; and build a small dam at the 120 m elevation line, and build a branch canal 3.28 km along the foot of the mountain to intercept water to the main channel. The total length of the water source point tunnel is 1.75 km, the total length of the channel is 11.34 km, and a total of 10.4 km2 of rainwater catchment area is retained along the route.

24 Research on the Implementation Path of Landscape Dispatch …

299

24.3.2 Hydrology and Water Resource Calculation According to the data of the nearby hydrological station, the 36-year runoff series of the dam site from 1981 ~ 2016 were obtained, and the annual distribution and annual average flow results of the dam site were shown in Tables 24.1 and 24.2. According to the annual average flow of the dam site, according to the formula of 100% empirical frequency × P = m/(n + 1), the annual average flow frequency of the dam site is obtained by using the P-III frequency curve to fit the line, and the average annual flow frequency at dam sites, the annual runoff frequency curve are shown in Table 24.3 and Fig. 24.2 respectively. Raskin et al. (1997) proposed in 1997 and internationally recognized that 40%, the degree of water resource development and utilization is a warning line indicator Table 24.1 Multi-year average flow results allocated to dam sites during the year (m3 /s) Location

Jan Feb Mar Apr

Dam site

0.3 0.5

0.7

Percentage 3.8 5.5 (%)

9.1

May Jun

1.2

1.4

Jul Aug Sep Oct Nov Dec Annual average

1.4 0.7 0.5

0.3

0.3

0.4

0.2

0.67

14.7 17.4 17.4 9.3 6.8

4.2

4.1

4.7

3.1

100

Table 24.2 Multi-year average flow results of dam sites (m3 /s) Year

Dam site

Year

Dam site Year

Dam site Year

Dam site

Year

Dam site

1959

0.742

1971

0.579

1983

0.654

1995

0.941

2007

0.384

1960

0.462

1972

0.339

1984

0.597

1996

0.594

2008

0.325

1961

0.755

1973

0.845

1985

0.354

1997

0.622

2009

0.472

1962

0.996

1974

0.625

1986

0.257

1998

1.137

2010

0.789

1963

0.447

1975

0.629

1987

0.533

1999

0.847

2011

0.310

1964

0.731

1976

0.598

1988

0.651

2000

0.592

2012

0.818

1965

0.770

1977

0.864

1989

0.706

2001

0.760

2013

0.716

1966

0.663

1978

0.358

1990

0.847

2002

1.095

2014

0.875

1967

0.594

1979

0.493

1991

0.693

2003

0.712

2015

0.785

1968

0.366

1980

0.654

1992

0.588

2004

0.664

2016

0.910

1969

1.093

1981

0.608

1993

0.597

2005

0.835

Average

0.672

1970

0.809

1982

0.716

1994

0.696

2006

0.897

Table 24.3 Average annual flow frequency at dam sites (m3 /s) Area (km2 )

X

Cv

Cs / Cv

Frequency (%) 5

10

20

50

75

85

90

95

34.4

0.672

0.33

2.0

1.07

0.97

0.85

0.65

0.51

0.45

0.41

0.35

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B. Liu and H. Fang

Flow (m3/s) X = CV = Cs/Cv =

0.672 0.33 2.0

Frequency (%)

Fig. 24.2 Runoff frequency curve

of the water scarcity index or water vulnerability index. The water diversion scheme intercepts a total of 14.7 km2 of rainwater catchment area, and the water diversion source is slope confluence, considering the downstream production and domestic water, ecological base flow, sediment and other factors, this study sets 35% (1

1–0.5

0.5–0.25

0.25–0.125

0.125–0.1

0.1–0.05

10.3

0.05–0.01

0, δ = const are positive definite: natural restrictions r =1 Vr kr sin ϕ0 (

) ( ) ( ) D (1)r, g = r, D (1) g , D (2)r, g

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V. V. Sidoryakina

Fig. 26.1 Distribution of 2D grid nodes ωh

( ) = r, D (2) g , D (1) ≥ δ1 E, D (2) ≥ δ2 E, ∀r, g ∈ H, where E is the identity operator, δ1 ≡ const > 0, δ2 ≡ const > 0. These properties will inherit the difference analogues of these differential operators. Building in the area G = G ∪ ┌ connected grid ωh steps in the h x , h y performed by methods that are quite fully presented in Samarskii and Vabishchevich (2004), Samarskii (2001). We assume that the origin of coordinates lies inside the region G. Grid node distribution ωh represent using Fig. 26.1. Figure 26.1 shows: ◦ there are strictly internal nodes; × there are border nodes; ◻ there are border nodes regular in each of the directions O x, O y; ∆x y irregular nodes in each direction O x, O y; ∆x , ∆ y there are irregular nodes in the direction O x, O y respectively. For the difference approximation of the operator D H (n) in the node x = (i, j ) on a two-dimensional grid ωh select the standard five-point pattern “cross” (Fig. 26.2): To write the grid functions, we accept the convention: H (n) (x, y, tn ) we will (n) (n) (n−1) denote H i, j ≡ H (i, j), Vr (x, y)—V r,i, j ≡ V r (i, j ), kr(n−1) (x, y, tn−1 )—k r,i, j ≡ (n−1)

(n)

(n)

(i, j ), f (n) (x, y, tn )— f i j ≡ f (i, j). To find the difference operator DH (n) ∼ D H (n) , approximating diffusion processes, we consider separately the operators D(1) H (n) ∼ D (1) H (n) , D(2) H (n) ∼ D (2) H (n) . We find:

kr

(a) in regular knots

Fig. 26.2 Difference schema template

26 Simulation of Sediment Transport in Coastal Systems, Taking …

323

• along the coordinate direction O x: D(1) Hi,(n)j

) ( R ∑ ( ) τ 1 bc,r = Vr kr(n−1) H (n) x 1 − ε r =1 sin ϕ0 x ⎛ ( n n R ∑ H i+h x , j − H i, j τbc,r (n−1) ⎜ 1 V r,i+ 2 h x , j k r,i+ 1 h x , j 2 h 2x 1 ⎜ ⎜ r =1 sin ϕ0 = ⎜ ) n n 1 − ε⎜ H i, j − H i−h x , j (n−1) ⎝ −V 1 k 1 r,i− 2 h x , j r,i− 2 h x , j h 2x

⎞ ⎟ ⎟ ⎟ ⎟, ⎟ ⎠ (26.16)

) 1( V r,i+h x , j + V r,i−h x , j , 2 ⎞−1 j+ 21 h y⎛ i+h { x { 1 ds 1 (n−1) x ⎝ = ( ) ⎠ ds y , k r,i− 21 h x , j (n−1) hx hx sx , s y kr

V r,i± 21 h x , j = (n−1)

k r,i+ 1 h x , j 2

j− 21 h y

1 = hy

j+ 21 h y

{

j− 21 h y

i

⎛ ⎝1 hx

{i i−h x

⎞−1 dsx ( ) ⎠ ds y , kr(n−1) sx , s y

1 1 1 1 i − h x ≤ sx ≤ i + h x , j − h y ≤ s y ≤ j + h y ; 2 2 2 2

(26.17)

• along the coordinate direction O y: (2)

D

Hi,(n)j

) ( R ∑ ( (n) ) 1 (n−1) τbc,r H = Vr kr y 1 − ε r =1 sin ϕ0 y ⎛ ( n n R ∑ H i, j+h y − H i, j τbc,r (n−1) ⎜ V r,i, j+ 21 h y k r,i, j+ 1 h y 2 h 2y 1 ⎜ ⎜ r =1 sin ϕ0 = ⎜ ) n n 1 − ε⎜ H i, j − H i, j−h y (n−1) ⎝ −V r,i, j− 21 h y k r,i, j− 1 h y 2 h 2y ) 1( V r,i, j+h y + V r,i, j−h y , 2 ⎛ ⎞−1 i+ 21 h x j+h y { { ds y 1 (n−1) ⎜1 ⎟ = ( ) ⎠ ds y , k r,i, j− 21 h y ⎝ (n−1) hy hy sx , s y kr

V r,i, j± 21 h y = (n−1)

k r,i, j+ 1 h y 2

i− 21 h x

j

⎞ ⎟ ⎟ ⎟ ⎟, (26.18) ⎟ ⎠

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V. V. Sidoryakina

=

1 hx

i+ 21 h x

{

i− 21 h x

⎛ ⎜1 ⎝ hy

{j j−h y

⎞−1 ds y ⎟ )⎠ (n−1) ( sx , s y kr

dsx ,

1 1 1 1 i − h x ≤ sx ≤ i + h x , j − h y ≤ s y ≤ j + h y ; 2 2 2 2

(26.19)

(b) in irregular knots • along the coordinate direction O x: (1)

D

Hi,(n)j

) ( R ∑ ( (n) ) 1 (n−1) τbc,r = Vr kr H x 1 − ε r =1 sin ϕ0 x ⎛ ( ⎧ n n R ∑ H i+h x , j − H i, j ⎪ τbc,r (n−1) ⎪ ⎪ ⎜ 1 V k 1 ⎪ r,i+ 2 h x , j r,i+ 2 h x , j ⎪ hx h x ⎪ 1 ⎜ ⎪ ⎜ r =1 sin ϕ0 ⎪ ⎪ ⎜ ) ⎪ n n ⎪ 1 − ε⎜ ⎪ H i, j − H i−h x , j ⎪ (n−1) ⎝ ⎪ ⎪ −V r,i− 21 h x , j k r,i− 1 h x , j ⎪ 2 ⎨ hx h ∗x ⎛ = ( n n R ⎪ ∑ ⎪ H i+h x , j − H i, j τbc,r (n−1) ⎪ ⎪ ⎜ V r,i+ 21 h x , j k r,i+ 1 h x , j ⎪ ⎪ 2 ⎪ hx h ∗x sin ϕ0 ⎪ 1 ⎜ ⎜ r =1 ⎪ ⎪ ⎜ ) ⎪ n n ⎪ 1 − ε⎜ ⎪ H i, j − H i−h x , j ⎪ (n−1) ⎝ ⎪ ⎪ −V r,i− 21 h x , j k r,i− 1 h x , j ⎩ 2 hx h x △

⎞ ⎟ ⎟ ⎟ ⎟, ⎟ ⎠ ⎞ ⎟ ⎟ ⎟ ⎟, ⎟ ⎠ (26.20)

D(1) Hi,(n)j

) ( R ∑ ( (n) ) 1 (n−1) τbc,r H x Vr kr = 1 − ε r =1 sin ϕ0 x ( ⎛ n n H i+h x , j − H i, j τbc,r (n−1) 1 k V 1 r,i+ 2 h x , j r,i+ 2 h x , j ⎜ R sin ϕ hx h ∗x+ ∑ 0 1 ⎜ ⎜ = ) n n 1 − ε⎜ H i, j − H i−h x , j ⎝ r =1 (n−1) −V r,i− 21 h x , j k r,i− 1 h x , j 2 hx h ∗x− △

⎞ ⎟ ⎟ ⎟, ⎟ ⎠ (26.21)

(i ± h x , j ) there is a boundary node in the direction O x, (i, j ) there is a border junction, irregular in direction O x; • along the coordinate direction O y: (2)

D

Hi,(n)j

) ( R ∑ ( (n) ) 1 (n−1) τbc,r H Vr kr = y 1 − ε r =1 sin ϕ0

△

y

26 Simulation of Sediment Transport in Coastal Systems, Taking …

⎛ ⎧ ⎪ ⎪ ⎪ ⎜ R ⎪ ⎪ ⎜∑ ⎪ 1 ⎪ ⎜ ⎪ ⎪ ⎜ ⎪ ⎪ ⎜ 1 − ε ⎪ ⎪ ⎝ r =1 ⎪ ⎪ ⎪ ⎨ ⎛ = ⎪ ⎪ ⎪ ⎪ ⎜ R ⎪ ⎪ ⎪ ⎪ 1 ⎜ ⎜∑ ⎪ ⎪ ⎜ ⎪ ⎪ 1 − ε ⎜ r =1 ⎪ ⎪ ⎝ ⎪ ⎪ ⎩

( n n H i, j+h y − H i, j τbc,r (n−1) V r,i, j+ 21 h y k r,i, j+ 1 h y 2 sin ϕ0 hy h y ) n n H i, j − H i, j−h y (n−1) −V r,i, j− 21 h y k r,i, j− 1 h y 2 h y h ∗y ( n n H i, j+h y − H i, j τbc,r (n−1) V r,i, j+ 21 h y k r,i, j+ 1 h y 2 sin ϕ0 h y h ∗y ) n n H i, j − H i, j−h y (n−1) −V r,i, j− 21 h y k r,i, j− 1 h y 2 hy h y

( ) i, j ± h y ∈ γh,y ; (2)

D

Hi,(n)j

325

⎞ ⎟ ⎟ ⎟ ⎟, ⎟ ⎠ ⎞ ⎟ ⎟ ⎟ ⎟, ⎟ ⎠ (26.22)

) ( R ∑ ( (n) ) 1 (n−1) τbc,r H = Vr kr y 1 − ε r =1 sin ϕ0 y ⎛ ( n n H i, j+h y − H i, j τbc,r (n−1) ⎜ R V r,i, j+ 21 h y k r,i, j+ 1 h y 2 h y h ∗y+ 1 ⎜ ⎜∑ sin ϕ0 = ⎜ ) n n 1 − ε ⎜ r =1 H i, j − H i, j−h y (n−1) ⎝ −V r,i, j− 21 h y k r,i, j− 1 h y 2 h y h ∗y− ( ) ∗∗ , i, j ± h y ∈ γh,y , (i, j) ∈ ωh,y △

⎞ ⎟ ⎟ ⎟ ⎟, ⎟ ⎠ (26.23)

( ) i, j ± h y there is a boundary node in the direction O y, (i, j ) there is a border junction, irregular in direction O y. In expressions (26.20)–(26.23) the notation is used: hx =

) ) 1( 1( h x + h ∗x , h y = h y + h ∗y , 2 2

h ∗x is the distance from the irregular node (i, j ) to the boundary node (i + h x , j ) or (i − h x , j ), ( ) h ∗ is the distance from the irregular node (i, j ) to the boundary node i, j + h y or (y ) i, j − h y , h ∗x+ is the distance between nodes (i, j) and (i + h x , j ), h ∗x+ ≤ h x ; h ∗x− is the distance between nodes (i, j) and (i − h x , j ), h ∗x− ≤ h x ; ( ) h ∗y+ is the distance between nodes (i, j) and i, j + h y , h ∗y+ ≤ h y ; ( ) h ∗y− is the distance between nodes (i, j ) and i, j − h y , h ∗y− ≤ h y . To find the difference operator DHi,(n)j it is necessary to substitute expressions for from D(1) Hi,(n)j , D(2) Hi,(n)j , derived from formulas (26.16)–(26.23).

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It is obvious that at regular knots the difference operator has the second order of approximation ) ( D Hi,(n)j − DHi,(n)j = O h 2x + h 2y ,

(26.24)

D Hi,(n)j − DHi,(n)j = O(1).

(26.25)

in irregular nodes

Approximating Eq. (26.12) with an explicit scheme, we obtain: H (n) − H (n−1) (n−1) = D H (n−1) + f (x, y, t), (x, y, t) ∈ C T . τ

(26.26)

However, in the so-called negative norm of the grid space (Samarskii and Vabishchevich 2004), the constructed approximation has the second order of approximation with respect to the steps of the spatial grid. We will focus on an implicit difference scheme, which can be symbolically represented as: H (n) − H (n−1) (n−1) = D H (n) + f (x, y, t), (x, y, t) ∈ C T . τ

(26.27)

For the numerical implementation of the resulting system of difference equations, the Seidel method can be used, which guarantees convergence at the rate of a geometric progression, the denominator of which is the smaller, the smaller the time step value.

26.5 Conclusion The article considers a model of transport of multi-fraction sediments in areas of complex shape, when the boundary of the area has the form of a curvilinear line. With the help of linearization methods (linearization on a time grid), the original nonlinear initial-boundary value problem was reduced to a chain of interconnected linear problems. To solve each of these problems, difference approximations are constructed on non-uniform grids near the boundary. Permissible values of time steps are determined. Conditions for the applicability of explicit and implicit schemes are demonstrated. Acknowledgements The study was financially supported by the Russian Science Foundation (Project No. 23-21-00509, https://rscf.ru/en/project/23-21-00509/)

26 Simulation of Sediment Transport in Coastal Systems, Taking …

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References Chalov SR, Efimov VA (2021) Granulometric composition of suspended solids: characteristics, classifications, spatial variability. Bull Maritime Univ 5(4):91–103 Leontiev IO (2001) Coastal dynamics: waves, currents, sediment flows. M.: GEOS Matishov GG, Pol’shin VV, Dyuzhova KV, Sushko KS, Titov VV (2017) Results of integrated studies of Holocene deposits of the Taganrog Bay of the Sea of Azov. Sci South of Russia 13(4):43–59 Sukhinov AI, Chistyakov AE, Sidoryakina VV (2018) Parallel solution of sediment and suspension transportation problems on the basis of explicit schemes. Commun Comput Inf Sci 910:306–321. https://doi.org/10.1007/978-3-319-99673-8_22 Sidoryakina VV, Sukhinov AI (2017) Well-posedness analysis and numerical implementation of a linearized two-dimensional bottom sediment transport problem. Zh Vychisl Mat Mat Fiz 57(6):985–1002. Comput Math Math Phys 57(6):978–994. https://doi.org/10.7868/S00444669 17060138 Sidoryakina VV (2019) Efficient algorithms for the numerical solution of the coupled sediment and suspended matter transport problems in coastal systems. In: Proceedings of the 21st international workshop on computer science and information technologies (CSIT 2019) series: Atlantis highlights in computer sciences, vol 3, pp 243–248 (2019). https://doi.org/10.2991/csit-19.201 9.42 Sukhinov AI, Sukhinov AA, Sidoryakina VV (2020) Uniqueness of solving the problem of transport and sedimentation of multicomponent suspensions in coastal systems structures. IOP Conf Ser: J Phys: Conf Ser 1479(1):012081. https://doi.org/10.1088/1742-6596/1479/1/012081 Samarskii AA, Vabishchevich PN (2004) Numerical methods for solving convection-diffusion problems. M.: Editorial Samarskii AA (2001) The theory of difference schemes. Basel, Marcel Dekker Inc., New York Zawisza J, Radosz I, Biegowski J, Kaczmarek LM (2023) Transport of sediment mixtures in steady flow with an extra contribution of their finest fractions: laboratory tests and modeling. Water 15:832

Chapter 27

Urban Water Operational Robustness Failure Preliminary Study: Step Forward Solution to Resilience Improvement of Future Sustainable City Jian Zang

Abstract A sustainable and resilient city is recognized as a coming future city design criteria. However, current cities in operational stage are facing kinds of challenges, which requires a solution for improving the efficiency (water, energy, and resources consumption) and safety (to both environment and human) in the built environment. Endpoint water management seeks to increase water resilience from the built environment during the operational stage by reducing the Water Demand (WD) and related chemicals used in treatment as well as energy/carbon-emission for pumping/treating water. The study is a preliminary experimental result aiming at city sustainability and resilience. We conducted a peer-reviewed, site investigation method and Index Decomposition Analysis (IDA) method to value the possible failure issues during the operational stage of the urban water system. The findings show that the WD can be substantially reduced by both management strategy and increasing the awareness of staff and occupants, which leads a significant success in city resilience work and microbial contaminates spreading to built environment. Those savings can be achieved by addressing the wastewater Base Flow (BF) and a framwork of resilience related was therefore concluded in the final. Furthermore, a water leakage issues solution could lower the microbial risk from the water cycling system. Future sustainable and resilient city is also highly recommended by adding health resilience and city resilience components. Precise management of the city could help in area of resilience and robustness improvement. Keywords Water Base-Flow Wastage · 16s rRNA sequencing · End-point water · Microbial contaminants

J. Zang (B) Joint International Research Laboratory of Green Buildings and Built Environments (Ministry of Education), Chongqing 400044, China e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_27

329

330

J. Zang

27.1 Introduction Nowadays, the world is facing serious environmental problems resulting from climate change, population growth, urbanization, and global warming. The gaps in the built environment from the operational stage to the design stage are already identified by Zang et al. (2022). The conflict between growing resource usage and resource efficiency is increasing. Among them, the waterside takes more focus, and Water Efficiency (WE) takes more focus because of water scarcity. An increasing energy and chemicals demand for treating water leads to a focus on water saving, which requires a solution for improving the operational material use efficiency in the built environment (Defra 2008). The global increase in demand for water and energy has significant environmental impacts. Wasting water also wastes related resources used to supply, treat and distribute the water to where it is used. In Europe, buildings account for around 40% of the total energy used for HVAC systems, but they ignore the energy used for domestic hot water (14% of the total) and are used for pumping water within high-rise buildings (Pérez-Lombard et al. 2008). Inadequate building management, ivory-tower system design or lack of continuous monitoring and neglected social acceptance have negative effects on water and energy use in dwellings (Amasyali and El-Gohary 2018). Water security is a significant global challenge exacerbated by climate change (Lowe et al. 2018). There is a strong link between water, energy, and carbon emission (Zang et al. 2020). The water lost in distribution systems due to leakage varies from 15–55% (Zang et al. 2020; Islam et al. 2011; Amoatey et al. 2018). It appears to be a serious problem in low- and middle-income countries (Makaya 2017). The water loss rate in Malatya City in Turkey, for example, was estimated to be 72% in 2014 and 52% in 2017 (Bozta¸s et al. 2019). In the US as well as other developed countries leaking accounts for more than 20% of total water consumption (Yazdekhasti et al. 2020). Based on the global water use estimation and real-world leakage assessment reports from Liu et al. (2020) and Zang et al. (2020), the estimated total leakage in the world is estimated to be about 2100 billion cubic meters and will be increasing at a rate of about 1.3% per year. Additionally, about 3.6 billion people live in potential water-scarce regions, and 3 out of 10 people in the world lack access to potable water (SDGs 2019). A preliminary Water Consumption (WC) analysis has already yielded interesting first insights into the significant amount of water wastage (Base Flow) that occurs due to malfunctioning appliances in student dormitories and various factors affecting water resilience like endpoint efficiency, total chemical consumption, total primary energy consumption and built environment safety. Indoor safety involves indoor water quality safety and human exposure and diffusion safety, which will be further studied in this study by using 16s rRNA sequencing compared to the safety standard. Clear enough that good indoor air quality (IAQ) management should include control of airborne pollutants, introduction and distribution of adequate outdoor air, and maintenance of acceptable temperature and relative humidity (Wallace et al. 1986). Thus, poor indoor air quality can cause health problems such as headaches, fatigue,

27 Urban Water Operational Robustness Failure Preliminary Study: Step …

331

eye irritation, allergies, asthma, and other respiratory diseases. It can also affect the cognitive function of students, such as their ability to concentrate and learn (Sadrizadeh et al. 2022). Air pollutants mainly arise from anthropogenic sources. For outdoor sources, these pollutants are principally originated from vehicle exhaust emission, particles that originate from brake and tire wear, and resuspension of particles that have previously settled on the road surface, especially the contamination from water to the air route is also potentially risky (Tunno et al. 2015). Indoor air pollutants include particulate matter (PM2.5, PM10, etc.), biological pollutants (bacteria, fungi, mould, spores, allergens, etc.) and hundreds of different chemical compounds, mainly volatile organic compounds (VOCs) (Ang 2004).

27.2 Methodology The 3 years of real-time data collected by Water Solution Demeter Company (WSDC) from 2016–2019 was classified in terms of the type of the building, temporal granularity, water consumption, and associated energy consumed predicted. Two types of buildings (office buildings “urban science building” and students’ dormitories “Windsor Terrace”), five types of temporal granularity (quarterly, hourly, daily, per trimester and academic yearly), and four factors (environmental, economic, social acceptance) were defined. Water consumption can be generated from 3 different methods given through WSDC data. The questionnaire was given by students (158) and with references from authorized institutes. Index decomposition analysis (IDA) is a popular method for detecting the factors affecting energy consumption or carbon emission intensity changes (Liu et al. 2020; Ang 2004; Zhou et al. 2021). Two-year real-time water consumption data from Sept 2016 to Aug 2018 was classified in terms of types of accommodation, occupancy, and temporal granularity. In detail, for students’ dormitories with en-suite or shared bathrooms, five types of temporal granularities (quarterly, hourly, daily, per trimester and academic yearly) and four factors (environmental, economic, and social acceptance) were defined. The efficiency of dormitory management and the effect of awareness improvement was observed based on 2-year continuous water consumption data recorded every 15 min for 9 blocks in 3 student dormitories at Windsor Terrace (WT) Hodgkin, Gurney, and Fife on the Newcastle University campus. Also, A systematic review has been done through the analysis of papers mainly taken 6 from the Web of Science Core Collection, which is the world’s most trusted citation index for scientific and scholarly research. Peerreviewed articles published between 2000 and 2021 were included in searches, and elements in lowering resilience were verified by literature review (Karagulian et al. 2015).

332

J. Zang

27.3 Results Figure 27.1 indicates the conceptual urban water cycling system map. Water from no matter laker, river, water treatment plant, rainwater harvesting system, or even reclamation plant shows a close relationship with the end-point user by connecting each other via pipes. Water taken from natural water bodies or water storage bodies, such as rivers, lakes, ponds, or underground aquifers, used as a source of water supply; Or refers to the water flowing into the first treatment unit of the water treatment plant. It will then distributed to the endpoint user through pipe work system, so the pipe management is very important for endpoint users. Apart from clean water distribution system (network), the wastewater or reclaimed water could also be used after the water treatment from reclamation plants, those water is not that clean as fresh one, microbial contaminants is able to reproduced there and affect the health of endpoint user. Figure 27.2 shows how the BF accounts for about 31.6% (contributing to 1182.6 m3 endpoint water loss) in a whole year of TWC. For the whole academic year 2017– 2018 for WT1-3, it could be a significant challenge for water resources, energy, and carbon neutrality. Financially, water wastage amounts to about £2500 for the period of the 2017–2018 academic year in WT 00, which had 69 occupants (£2.37 per cubic meter) once the KPI maintenance check could be widely used the whole last year. As Fig. 27.3 shows, WC and base flow did decrease more and less in each block. Among those changes, WT (Hodgkin) only had a slight decrease for a few days and then jumped to the original base flow or even higher due to students’ back. However, staff meetings helped in saving water and cutting base flow. In detail, 67.5 and 44.5% base flow were cut by the meeting in WT (Gurney) and WT (Fife) separately. Although the WCPC rebounded to its original level after a few days, the benefits of the meeting, as well as the management strategy, should not be neglected. As a result, more frequent and long-term effective management is required to save water. In the current report, the cleaner staff meeting proved that it did help in saving water and base flow, but long-term continuous monitoring management is also required to keep the achievements. Figure 27.4 indicates the 3 pillars of sustainable elements and the meaning of robustness and resilience. L in the figure indicates the learning ability to increase R (Robustness), r (City recovery Rate), and D (Recovery Degree). The focus is to increase Robustness. Recovery rate, Recovery Degree and narrow the failure recovery gap of the city system when facing or will face challenges. Sustainability refers to the 3 pillars’ elements but also in terms of bearable, equitable and viable areas. Figure 27.5 indicates the city resilience components and health resilience components from peer-reviewed publications and site investigation surveys at Newcastle University and Chongqing University. Sustainable urban design and liveable cities are the top two widely accepted elements for future resilient cities. Also, City resilience and health resilience are complex. City resilience heavily influences health resilience.

27 Urban Water Operational Robustness Failure Preliminary Study: Step …

333

Fig. 27.1 Water cycle route and microbial pipe contamination conceptual figure in the urban city. Source adapted from Liu et al. (2020); AWWA (2023)

Similarly, citizens’ health resilience is one of the main parts of city resilience. Maintenance is a very easily ignored element, and the raw publication mentioned the relationship between maintenance and health resilient city.

27.4 Discussion The current study used the peer-reviewed and site investigation identification method from previous studies. Figure 27.1 indicated the mapping distribution and each unit of water cycling system. But research indicated that microbial pollutants in the pipe system may have a negative effect on human (Liu et al. 2020). The attached sustainable development goal emphasizes the available water definition, which is close to

334

J. Zang

Fig. 27.2 Baseflow change after site investigation (KPI maintenance check) on June 8th 2017, in students’ dormitories Windsor Terrace

city robustness (the ability against risk). The results from Fig. 27.2 indicate the potential for water efficiency improvement, urban energy consumption saves, and global carbon reduction is significant. The KPI maintenance check is very successful with the help of fact that engaging with the maintenance staff, which is also similar to explanation in previous studies (Zang et al. 2020). The influence factors are copied to those explained by IDA (Liu et al. 2020; Ang 2004; Zhou et al. 2021). Environmentally, the daily wastage indicates that the indirect environmental impacts of the endpoint water wastage amount to about 89.88 kg chemicals and 354.8 kg CO2 emission to the atmosphere during water treatment, supplying and conveyance (76 g chemicals, 300 g CO2 e per m3 used in water treatment and about 1000 g for conveyance depend on the urban water pipe system design) (Zang et al. 2020). The total energy used for water treatment, pumping, conveyance, and boosting is more than 8% of the total primary energy, and they should all be served to the endpoint successfully. However, the thesis here identified the gap and different watersupplying networks to explain the relationship between water consumption in the endpoint and global energy. Water in the endpoint of the building (residential room or industry plaint) should consume about 3.5kWh/m3 primary energy and leads to approximately 3 kg equal carbon dioxide emission, globally 3.08–8.25 million tons (Carbon data source: (Zang et al. 2020)). The wastage here is because of BF, which is a copy of the results from previous BF and gap studies. The potential of operational energy saving and carbon emission reduction is more than 2–4% of the total global. Details, the several ‘zero cost’ engagement methods have already claimed to save water as well as carbon emission by 30–50% of the total (8% of the global total). Further work will analyze the factors contributing to the real WD and BF and will then identify/report the malfunction of appliances and predict real DWC automatically through an Application Programming Interface (API) for live data. In conclusion, the approach is a cost-efficient way of reducing WD in dwellings which indirectly also reduces the pressure on water resources and related energy/chemicals

27 Urban Water Operational Robustness Failure Preliminary Study: Step …

335

Fig. 27.3 Water wastage (base flow) reduction and water consumption analysis in students’ dormitories owing to maintenance management (maintenance staff meeting)

336

Fig. 27.4 Graphic framework for the future resilient city (Sustainability and Resilience)

Fig. 27.5 City resilience components and health resilience in urban city

J. Zang

27 Urban Water Operational Robustness Failure Preliminary Study: Step …

337

demands. Water quality results, qPCR and 16s rRNA sequencing readings for water source and end-point water have been tested to ensure the safety of drinking water quality supporting data from source (Zang et al. 2020). The results illustrate that the indoor water quality in the built environment is far under the safety standard. Because of the limited space here, additional result tables will be added to supporting material. Figure 27.4 showed a sustainable system should satisfy three non-neglected aspects (economic, environmental and social). Firstly, technological feasibility and economic efficiency, environmental effects (including the quantity of carbon emission) and social acceptance are three aspects which have a closed and non-neglected relationship to real-world system efficiency (Liu et al. 2020). In detail, affordable capital cost and a reasonable pay-back period are required for sustainability. Water and energy saving should be the key point in the environmental part, but the total carbon emission and embodied carbon emission also need identification as a contribution to combat climate change. Moreover, the social aspect is always easy to ignore but very important to the real-world system. Social acceptance has a significant influence on system sustainability. It means it has similar trend like previous publication but is more thoughtful in current framework in Figs. 27.4 and 27.5 (Zang et al. 2022; WHO Heat and Health 2018). The potential endpoint of water-saving is more than 8% of total carbon emissions in the world, and it have close relationship with energy and health (WEO 2010; WHO Flooding 2017; WHO Ambient 2023; WHO Health effects of particulate matter 2013), our preliminary research is therefore proved that a deeper research regards to those sustainability and resilience mentioned is needed in the future. Intelligent methodology like machine learning or supervised-digitalmanagement can also help in sustainability improvement but it is not considered in the current study (Fang et al. 2023).

27.5 Conclusion A resilience-related preliminary thinking and analysis was conducted according to the water route from the water treatment plant to the endpoint user. Failures related to water supply, efficiency and safety were identified. The study conducted failure identification analysis at Newcastle University in the UK and Chongqing University in China. Results indicated that water leakage and pollutants from water leakage to the indoor air have a significant impact on the urban water system as well as the future city resilience. . Future city sustainability is not only about 3 pillars elements but also relating to resilience management. . Water demand is normally bigger than the real water demand owing to leakage. . Proper management has a significant impact on water efficiency improvement. . Microbial pollutants in the water systems or pipelines may threaten indoor air quality via leakage issues.

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. The current city resilience could be improved by addressing water-related robustness failures like water leakage and increasing water management. To satisfy future city water-related resilience and improve the city’s robustness, we need to consider further solutions or increase awareness of city water leakage and pollutant spreading. A framework is therefore concluded for future research to consider both sustainability and resilience together.

References Amasyali K, El-Gohary NM (2018) A review of data-driven building energy consumption prediction studies. Renew Sustain Energy Rev 81:1192–1205 Amoatey P, Minke R, Steinmetz H (2018) Leakage estimation in developing country water networks based on water balance, minimum night flow and component analysis methods. Water Pract Technol 13(1):96–105 Ang W (2004) Decomposition analysis for policy making in energy: which is the preferred method? Energy Policy 32(9):1131–1139 AWWA, American Water Works Association (2023) Urban water cycle. https://www.awwa.org/Pub lications/Authoring-Permissions. Accessed 07 Apr 2023 Bozta¸s F, Özdemir Ö, Durmu¸sçelebi F, Firat M (2019) Analyzing the effect of the unreported leakages in service connections of water distribution networks on non-revenue water. Int J Environ Sci Technol 16(8):4393–4406 Defra F (2008) Future water: the government’s water strategy for England. Department for Environment, Food and Rural Affairs London. Article 105627 Fang X, Zang J, Zhai Z, Zhang L, Shu Z, Liang Y (2023) Exploring potential dual-stage attention based recurrent neural network machine learning application for dosage prediction in intelligent municipal management. Environ Sci Res Technol 2023(9):890–899 Islam MS, Sadiq R, Rodriguez MJ, Francisque A, Najjaran H, Hoorfar M (2011) Leakage detection and location in water distribution systems using a fuzzy-based methodology. Urban Water J 8(6):351–365 Karagulian F, Belis CA, Dora C, Prüss-Ustün A, Bonjour S, Adair-Rohani H, Amann M (2015) Contributions to cities’ ambient particulate matter (PM): a systematic review of local 385 source contributions at global level. Atmos Environ 120:475–483, 386. https://doi.org/10.1016/j.atm osenv.2015.08.087 Liu Y, Chen B, Wei W, Shao L, Li Z, Jiang W, Chen G (2020) Global water use associated with energy supply, demand and international trade of China. Appl Energy 257:113992 Lowe JA, Bernie D, Bett P, Bricheno L, Brown S, Calvert D, Clark R, Eagle K, Edwards T, Fosser G (2018) UKCP18 science overview report. Met Office Hadley Centre: Exeter, UK Makaya E (2017) Performance based water loss management for Gweru, Zimbabwe. Am J Water Resour 5(4):100–105 Pérez-Lombard L, Ortiz J, Pout C (2008) A review on buildings energy consumption information. Energy Build 40(3):394–398 Sadrizadeh S, Yao R, Yuan F, Awbi H, Bahnfleth W, Bi Y, Cao G, Croitoru C, Dear R, Haghighat F, Kumar P, Malayeri M, Nasiri F, Ruud M, Sadeghian P, Wargocki P, Xiong J, Yu W, Li B (2022) Indoor air quality and health in schools: a critical review for developing the roadmap for the future school environment. J Build Eng 57:104908 SDGs Sustainable development goals (2019). Available at: https://www.un.org/development/desa/ disabilities/envision2030.html. Accessed 05 Jan 2023

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Tunno BJ, Dalton R, Michanowicz DR, Shmool JLC, Kinnee E, Tripathy S, Cambal L, Clougherty JE (2015) Spatial patterning in PM 2.5 constituents under an inversion-focused sampling design across an urban area of complex terrain. J Expo Sci Environ Epidemiol 26:385–371 Wallace LA, Pellizzari ED, Hartwell TD, Whitmore R, Sparacino C, Zelon H (1986) Total exposure assessment methodology (team) study: Personal exposures, indoor-outdoor relationships, and breath levels of volatile organic compounds in New Jersey. Environ Int 12(1):369–387 WEO (2010) World energy outlook. International Energy Agency. New York WHO Ambient (outdoor) air pollution (2023) World Health Organization. https://www.who.int/ news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-health. Accessed 08 Mar 2023 WHO Flooding (2017) Managing health risks in the WHO European region. World Health Organization, Copenhagen. ISSN 978289052795 WHO Health effects of particulate matter: policy implications for countries in Eastern Europe, Caucasus and central Asia. World Health Organization, Copenhagen: WHO Regional Office for Europe (2013) WHO Heat and Health (2018) https://www.who.int/news-room/fact-sheets/detail/climate-changeheat-and-health. Accessed 05 Jan 2023 Yazdekhasti S, Piratla KR, Sorber J, Atamturktur S, Khan A, Shukla H (2020) Sustainability analysis of a leakage-monitoring technique for water pipeline networks. J Pipeline Syst Eng Pract 11(1):04019052 Zang J, Royapoor M, Acharya K, Jonczyk J, Werner D (2022) Performance gaps of sustainability features in green award-winning university buildings. Build Environ 207:108417 Zang J, Kumar M, Werner D (2020) Real-world sustainability analysis of an innovative decentralized water system with rainwater harvesting and wastewater reclamation. J Environ Manag:111639 Zhou D, Huang F, Wang Q, Liu X (2021) The role of structure change in driving CO2 emissions from China’s waterway transport sector. Resour Conserv Recycl 171

Chapter 28

Reason Analysis and Countermeasure Research on Emulsified Oil of Zhen 2 Lian Lei Haoran

Abstract Crude oil emulsion refers to a homogeneous mixture of natural crude oil and water, in which crude oil components are dispersed in water to form a state similar to emulsion. Emulsified oil is an important problem in the process of crude oil processing, storage, transportation and treatment. It has a great influence on the corrosion of transmission pipelines, the formation of sediments and the separation of oil and gas. In order to deal with emulsified oil, this paper analyzes the causes of emulsified oil, analyzes its chemical composition, and develops a demulsifier formula for this specific situation. At the same time, according to different emulsified oil components, various process conditions are studied, and the problem of difficult treatment of emulsified oil is successfully solved. Keywords Changqing oilfield · Emulsified oil · Crude oil demulsification · Oil sludge

28.1 Introduction The 11th Oil Production Plant of Changqing Oilfield Company produces 2846 m3 of emulsified oil annually, accounting for 0.17% of the annual output, showing an increasing trend year by year. Among them, Taibailiang operation area has 1461 m3 , accounting for 49.5%, which seriously affects the normal operation of gathering and water injection system. There are three main problems: first, emulsified oil and sewage sludge make the system operation difficult; second, emulsified oil affects the downstream water quality; third, emulsified oil occupies crude oil production (National Standard GB/T 2012; Dong et al. 2018). This study analyzed the formation mechanism of emulsified oil and explored the factors influencing the emulsified oil content, such as wellbore materials (solid particles) and the native components of

L. Haoran (B) Changqing Oilfield Company, Oil Production No. 11, Xi’an, China e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_28

341

342

L. Haoran 4000 whole plant

Taibailiang

Proportion of emulsified oil (%)

3500

proportion 45.29

3568

49.54

3335

3000

41.56

42.21

42.71 2666

2426

2500 2235 2000

1461

1500

1284

1000 721

813

925

500 0

2018

2019

2020

2021

2022

Years

Fig. 28.1 The change trend of emulsified oil production in the past five years

crude oil (Luo et al. 2009; Dong et al. 2013; Zhu 2007; Zhou et al. 2011; Mukherjee et al. 2011; Zhang et al. 2012) (Fig. 28.1).

28.2 Component Analysis of Emulsified Oil 28.2.1 Centrifugal Separation The analysis was carried out according to GB/T 6533-2012 crude oil water and sediment determination method (centrifugation method). At room temperature, after 4000 r/min high-speed centrifugation for 10 min, the sample was divided into four layers after centrifugation. The upper layer is oil, the second layer is gel, the third layer is water, and the fourth layer is solids (Fig. 28.2).

28.2.2 Microscopic State Observation Observed under a polarizing microscope, the emulsified oil contains a large number of black opaque components, forming a network structure, which encapsulates oil and water and is difficult to separate. The black component after centrifugation is significantly reduced, but there are still black components wrapped on the surface of oil–water droplets, preventing the coalescence between droplets. Therefore, we

28 Reason Analysis and Countermeasure Research on Emulsified Oil …

343

Fig. 28.2 Photos of emulsified oil after centrifugal separation

Fig. 28.3 Microscopic imaging of emulsified oil before and after centrifugation

speculate that the black component is the main factor for the high stability of the emulsion (Fig. 28.3).

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L. Haoran

28.3 Analysis of Causes and Influencing Factors of Emulsified Oil 28.3.1 Clear Zhenerlian Emulsified Oil, Sewage Sludge Composition 28.3.1.1

Proximate Analysis

Through the centrifugal separation method, the mechanical impurities at the oil– water interface were obtained. After drying, toluene was added to the mechanical impurities, fully shaken to dissolve them, filtered, and then dried and weighed. Then n-heptane was added, dissolved at 60 °C, dried and weighed after filtration. Then add hydrochloric acid, filtration, drying, weighing. The iron content was determined according to the method in reference (Li et al. 2014), and the content of amides and acid insolubles was determined by infrared spectroscopy (Table 28.1). The results showed that the main components of emulsified oil and oily sludge were resins, asphaltenes, FeS, amides and other acid-insoluble substances (organic impurities and inorganic scale CaCO3 ).

28.3.1.2

Comparison of Emulsified Oil Components with Upstream Site and Single Well Crude Oil Components

By comparing the components of Zhen 2 emulsified oil, upstream stations and single well crude oil, it is found that the content of colloid and asphaltene in Zhen 5, Zhen 12, Zhen 14 and Zhen 46 is high, containing a small amount of FeS, calcium carbonate, amide substances and acid insoluble substances (as shown in Table 28.2), which is judged as the source site of stable substances in emulsified oil.

28.3.2 The Effect of Native Components on Dehydration Rate Was Clarified 28.3.2.1

Comparison of the Upstream Stations of Zhen 2 Lian

Taking Zhen 2 Lian as the center and the upstream water-bearing oil station as the skeleton, the content of colloid, asphaltene and mechanical impurities at each station is analyzed, and the dehydration rate is obtained by demulsification experiment (Chen et al. 2020). The analysis shows that resin, asphaltene and mechanical impurities are inversely proportional to the dehydration rate of crude oil, which are the main primary factors affecting crude oil demulsification.

7.1

24.1

Calcium carbonate

Amide substance

Insoluble content

16.5

FeS

20.1

8.9

14.9

26.3

28.4

25.5

7.3

16.4

22.4

26.4

37.9

12.4

6.8

16.5

20.1

47.5

9.6

7.9

14.9

34.3

10.7

12.6

16.1

26.3

Sample 3

29.8

31.8

20.5

Gel

Sample 2

Sample 1

Sample 2

Sample 1

Sample 3

Oil sludge (percentage of components)

Emulsified oil (percentage of components %)

Bituminous

Component

Table 28.1 Component analysis of emulsified oil and sewage sludge

9.33

9.33

12.52

19.45

27.13

Average value

/

Fracturing fluid guar gum

Scaling products

SRB corrosion products

In-place oil

Speculative source

High performance liquid chromatography

Muriatic acid

Spectrophotometric method

Normal heptane

Toluene

Test method

28 Reason Analysis and Countermeasure Research on Emulsified Oil … 345

346

L. Haoran

Table 28.2 Analysis of crude oil composition of upstream site and single well in Zhen er Site/single well

Proportion of components (%) Gel

Bituminous

FeS

Calcium carbonate

Amide substance

Emulsified oil

31.8

20.5

16.5

7.1

24.1

Zhen 2 Lian

25.7

12.6

6.5

3.4

5.7

Zhen 5 Zhuan

24.8

9.97

3.2

8.6

6.8

Zhen 14

22.78

9.79

2.1

7.8

5.4

Zhen 48

19.89

5.51

9.2

5.9

2.1

Zhen 30

18.69

8.12

0.6

3.2

2.3

Zhen 12

23.47

6.75

2.6

3.8

3.8

Zhen 46

22.75

9.64

3.6

1.2

4.2

Zhen 55

20.01

8.23

2.1

6.2

1.3

286-72X

15.86

4.14

0

0.11

0

264-1

16.7

9.79

0

0

0.3

289-47X

13.25

5.85

0.12

0

0

306-13

11.68

7.8

0.3

0

0.1

308-32A

9.5

6.5

0

0.1

0

276-5

10.6

7.6

0.1

0

0

98-295

10.2

2.2

0.03

0

0

303-15

13

3.5

0

0

0.4

303-16

1.5

9.6

0

0.06

0.1

380

3.5

6.7

0

0

0

328-84

16.9

2.8

0.06

0

0

330-84

10.5

0.8

0

0.05

0.06

Insoluble content

It can be seen from Fig. 28.4: (1) The colloid content of Zhen 5, Zhen 12, Zhen 14 and Zhen 46 is higher than the average level of the block. The total liquid volume is 980 m3 /d, accounting for 52.7% of the crude oil volume of Zhen 2. (2) The asphaltene content of Zhen 5 is the highest, the liquid volume is 460 m3 /d, accounting for 24.6% of the crude oil of Zhen 2. (3) The content of impurities in Zhen 14 and Zhen 5 was high. Combined with the mixed dehydration test, it was found that the content of impurities was inversely proportional to the dehydration rate. 28.3.2.2

Comparison of Native Components of the Whole Plant Site

Through the four-component analysis of the relationship between the proportion of resin, asphaltene and mechanical impurities in the crude oil ‘s original components

28 Reason Analysis and Countermeasure Research on Emulsified Oil … colloid mechanical impurities

25

asphaltene Dehydration rate(% ) 96.5

96.2

95.6

20

content (%)

347

94.7

94.6

94.2

15

93.8

10

5

0

Zhen 14

Zhen 48

Zhen 46

Zhen 30

Zhen 55

Zhen 12

Zhen 5

The name of Zhenerlian upstream site

Fig. 28.4 Influencing factors of dehydration rate in upstream site of Zhen 2 Lian

and the increment of emulsified oil and the dehydration rate of crude oil in the room (as shown in Fig. 28.5), it is clear that the content of resin, asphaltene and mechanical impurities is one of the factors affecting the production of emulsified oil. 2000

Annual increment of emulsified oil

dehydration rate

100

1600

94.6

94.6

95.6

94.9

94.5

95.3

1400

92.3 91.4

91.1

1200

1040

1000

90

962

800 600 434

400

408

262

200

160

125

105

18

Zh 8

ua Zh 12 Zh en

11

ua

n

n ua Zh

ua Zh en Zh

2

4 Zh en

Zh

ua

n

n

an Li 1 en g

4 M

en Zh

Zh en

an Li

an Li 3 en

an Li 1

2L ia n Zh

Zh en

en Zh

80

n

10

0

Name of the whole plant site

Fig. 28.5 Crude oil indoor dehydration rate and emulsified oil increment of each site

dehydration rate (%)

93.5

Zh en

Annual increment of emulsified oil (m3)

1800

348

L. Haoran 92 91.6

91 91

90.7

Dehydration rate(%)

90.6

90

89.1 89 88.4

88 1

2

3

4

5

6

drilling materials

Fig. 28.6 The influence of drilling material on dehydration rate. Note 1. crude oil + demulsifier; 2. crude oil + demulsifier + corrosion inhibitor; 3. crude oil + demulsifier + paraffin remover; 4. crude oil + demulsifier + scale inhibitor; 5. crude oil + demulsifier + guar gum fracturing fluid; 6. crude oil + demulsifier + EM30S fracturing fluid

28.3.3 The Influence of Well Entry Materials on Emulsified Oil is Clarified 28.3.3.1

Comparison of Dehydration Rate Affected by Drilling Materials

Through the demulsification and dehydration test of the mixture of the well material and the upstream crude oil of Zhen 2, it is found that the effect of the well material on the crude oil dehydration is not obvious (as shown in Fig. 28.6) and can be ignored. It can be seen from Fig. 28.6: (1) Chemical additives: The effect of chemical additives such as corrosion inhibitor, paraffin remover and scale inhibitor on crude oil dehydration (less than 1%) is not obvious and can be ignored. (2) Fracturing measures: Fracturing measures will lead to a decrease in crude oil dehydration rate, but at the same time, the base of well fluid volume is low, and the impact can be ignored. 28.3.3.2

Influence of Field Measures on Dehydration Rate

The fracturing measure was completed on September 1st in the upstream 290-71 of 14 increments in the town. The crude oil samples of the wellhead before and after the measure and the crude oil samples of the wellhead after the completion, the general authority of Zhen 14 increments and the general authority of Zhen 2 were taken for the dehydration rate comparison test. It was found that the dehydration rate decreased

28 Reason Analysis and Countermeasure Research on Emulsified Oil …

349

Table 28.3 Comparison of system dehydration rate after measures Sample name

Demulsifier concentration (ppm)

Before measures

100

290-71

Zhen 14

Zhen 2 Lian

Average

98.7

94.6

93.8

95.7

1 day after the measure

86.4

89.8

90.1

88.8

7 days after the measure

89.5

91.6

92.6

91.2

14 days after the measure

98.5

94.6

93.8

95.1

21 days after the measure

98.5

94.6

93.8

95.1

Table 28.4 Factor level table Factor

Level

Colloid (%)

Asphaltene (%)

Miscellaneous machinery (%)

Guanidine gum fracturing fluid (%)

EM30S fracturing fluid (%)

10

Five

Five

Five

Five

20

10

10

10

10

30

15

15

15

15

by 6.9% on average after the measure, and the dehydration rate recovered 95% after 7 days. After 14 days, the dehydration rate basically returned to normal (Table 28.3).

28.3.4 Orthogonal Test Analysis to Determine the Main Cause of Emulsified Oil Formation For the 5-factor 3-level test, the orthogonal test scheme of L18 37 was designed, and a total of 18 groups of tests were carried out. The range R indicates the influence of each factor on the dehydration rate. It can be concluded that R (internal factor) > R (external factor), of which R (resin) > R (asphaltene) > R (machine miscellaneous), that is, the resin and asphaltene in crude oil are the main factors for the formation of emulsified oil (Tables 28.4 and 28.5).

28.3.5 The Influence of System Operation on Emulsified Oil 28.3.5.1

The Variation of Emulsified Oil with the System

The dehydration rate of crude oil from different upstream sites was tested, and it was found that the dehydration rate of the upstream site was higher than that of the downstream site, that is, under normal production conditions, the more complex the

350

L. Haoran

Table 28.5 Dehydration rate orthogonal test table (L18 37 ) Factor Test number Gel Bituminous Miscellaneous Guanidine EM30S / machinery (%) gum frac-turing fracturing fluid (%) fluid (%)

/

Dehydration rate (%)

1

1

1

1

1

1

1

1

82.3

2

1

2

2

2

2

2

2

72.1

3

1

3

3

3

3

3

3

58.6

4

2

1

1

2

2

3

3

79.6

5

2

2

2

3

3

1

1

69.8

6

2

3

3

1

1

2

2

63.2

7

3

1

2

1

3

2

3

64.3

8

3

2

3

2

1

3

1

61.2

9

3

3

1

3

2

1

2

55.9

10

1

1

3

3

2

2

1

69.9

11

1

2

1

1

3

3

2

78.6

12

1

3

2

2

1

1

3

66.7

13

2

1

2

3

1

3

2

75.4

14

2

2

3

1

2

1

3

72.4

15

2

3

1

2

3

2

1

71.2

16

3

1

3

2

3

1

2

63.5

17

3

2

1

3

1

2

3

59.9

3

3

1

53.2

18

3

2

1

2

I

428.2 435.0

427.5

414.0

408.7

II

431.6 414.0

401.5

414.3

403.1

III

358.0 368.8

388.8

389.5

406.0

K1

71.37 72.50

71.25

69.00

68.12

K2

71.93 69.00

66.92

69.05

67.18

K3

59.67 61.47

64.80

64.92

67.67

R

12.27 11.03

6.45

4.13

0.93

crude oil composition, the lower the dehydration rate, and the easier the formation of emulsified oil (Fig. 28.7). After the measures, the dehydration rate is between 97 and 100% for single well crude oil, 94–97% for pressurization point, 92–94% for transfer station, and 91–92% for combined station.

28 Reason Analysis and Countermeasure Research on Emulsified Oil …

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100 99 98

Dehydration rate (%)

97 96 95 94 93 92 91 90

0

5

10

15

20

25

30

35

40

45

days

Fig. 28.7 The variation of dehydration rate with the system

28.3.5.2

The Change Rule of Emulsified Oil Increment with Time

The water-bearing oil of Zhen 2 oil removal tank was taken and stood for 72 h. The proportion of each component in the natural state and the addition of demulsifier was observed. It was found that the longer the standing time, the less the amount of water removed, the more stable the emulsified layer, and the more emulsified oil (Fig. 28.8). Proportion of original water layer Proportion of water layer with demulsifier

Proportion of original emulsion layer Proportion of demulsification emulsion layer

70 65

63

60

62 59 53

50

proportion(%)

44 40

38

44

44

44

44

37 32

30

28 23

20

10 9.7

9.8

10.3

0 0.5 0

0.9 10

1.2 20

14.6

12

1.4

1.2 30

21

21

21

21

21

15

15

15

15

15

1.4 50

1.4 60

1.4

1.4 40

dwell time(h)

Fig. 28.8 The proportion of each component after standing for 3 days

1.4 70

80

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L. Haoran

28.4 Treatment Measures of the Second Emulsified Layer in Zhen 2 28.4.1 Optimize the Mechanical Oscillation Dehydration Process The advantages and disadvantages of each indoor emulsified oil demulsification technology are shown in Table 28.6. All kinds of samples were first vibrated with DU vibration device for 10 min, and then centrifuged for 20 min. The oscillation effect significantly reduced the amount of chemical agent and improved the dehydration effect. The water content in the purified oil was 0–0.5%, and the oil content in the extracted water was 0–100 mg/L (Table 28.7). Table 28.6 Comparison of indoor emulsified oil demulsification technology Aging oil treatment method

Experimental result

Exist problem

Thermochemical treatment After 48 h for most samples, 1. demulsification dehydration the purified oil contained 0.5% time 24–48 h water 2. out of water black Centrifugal separation process

Can realize oil–water separation, four times of centrifugation, purified oil water content is less than or equal to 1%

1. no chemical agent or application of conventional demulsifier centrifugal dehydration out of water black, unable to eliminate the emulsion layer 2. The requirement of 0.5% water content cannot be met

Ultrasonic treatment process

1. Oil–water separation cannot be realized without demulsifying agent 2. add demulsifier cannot improve the demulsification effect

Has no obvious effect on demulsification of polymer-containing produced fluid and aged oil

Mechanical vibration + centrifugation

1. no demulsifier, purified oil water 1–3% 2. After the demulsifier is added, the water content of purified oil is ≤ 0.5%

Without demulsifying agent out of water black, cannot eliminate the emulsion layer

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Table 28.7 Laboratory evaluation of mechanical shock demulsification + centrifugal dehydration process Emulsion

Demulsifier (ppm)

Breaker (ppm)

Water in treated oil (%)

Oil in the separated water (mg/L)

Indoor simulated emulsified oil

120

200

0

0

Field emulsified oil

150

300

0.3

0–50

Field complex emulsion

150

300

0.5

40–100

Complex emulsified oil

150

0

0.1

10–20

Table 28.8 One-time demulsification general authority sample Sample name

A demulsification dehydration rate (%)

Secondary demulsification dehydration rate (%)

45 °C

45 °C

50 °C

55 °C

50 °C

55 °C

Indoor Zhen 5 sample

91.2

93.8

96.7

96.7

98.4

98.9

Field sample 1

82.1

88.4

90.6

91.3

92.7

96.9

Field sample 2

80.1

87.9

91.3

92.4

93.5

98.1

Field sample 3

82.3

87.5

90.1

90.8

93.4

96.7

28.4.2 Carry Out Pipeline Demulsification Test Aiming at the problem of high asphaltene content in Zhen 5, the pipeline demulsification test was carried out, and the average dehydration rate was increased from 87.9% to 97.2%. It was found that the dehydration rate was better than the endpoint dosing at the same concentration, and the dosing concentration was lower than the endpoint dosing at the same dehydration rate (Table 28.8).

28.4.3 Demulsifier Selection Preliminary experiments on demulsifier optimization were conducted in the Zhen 2 and Zhen 4 (experimental results shown in Fig. 28.9). The dehydration efficiency of SW-30 was higher than YT-100 and has been widely implemented. After using SW-30 demulsifier, the centrifugal water content of three-phase separator is less than 0.1%, and the average content of suspended solids in water is 206 mg/ L. The field operation is stable and better than YT-100 demulsifier (Fig. 28.10).

354 a)

L. Haoran

0.6

b)

SW-30

YT-100 0.5

0.40 YT-100

SW-30

0.35

0.5

0.3

0.3

0.3

0.3

0.3

0.3

0.3

0.3

0.25 0.2

0.2

0.2

0.15

0.0

0.05

0.05

3

4

0 1

2

0.05

0.05

6

7

0

0.25 0.2 0.20 0.15 0.15 0.1

0.1

0.1 0.05

0.05

6

7

0.05 0

0

5

0.25

0.10

0.1 0.05

the dehydration rate(%)

the dehydration rate(%)

0.30

0.4

0.4

0.00

8

1

2

0

3

4

5

0

8

days

days

Fig. 28.9 Water cut curve diagram of three-phase outlet of Zhen 2 and Zhen 4 350 YT-100 300

SW-30 312

290

Suspension content (mg/L)

271 250 220 200 160 150 127 100

50

0

Fig. 28.10 Zhen 2 three-phase water quality suspended solids content comparison diagram

28.4.4 The Mechanical Vibration Emulsified Oil Treatment Test Was Carried Out In 2022, emulsified oil treatment was carried out in Zhen 2, and emulsified oil treatment was carried out by mechanical shock dehydration process. A total of 4748 m3 emulsified oil was treated, and the concentration of chemical agent was 120–450 mg/ L. After treatment, the water content of purified oil was 0–0.3%, the mechanical impurity was 0–0.01%, and the oil content of sewage was 50–100 mg/L, but there was a certain fluctuation.

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28.5 Conclusion Through the pipeline demulsification test, the average dehydration rate was increased by 9.3%, and the increment of emulsified oil was reduced by 638 cubic meters. Mechanical shock demulsification + centrifugal treatment of Zhen 2 emulsified oil 4748 square, recovery of purified oil 118.7 square. Mastered the characteristics of Zhen 2 emulsified oil components and the main causes of formation. The countermeasures of pipeline demulsification, drug optimization and treatment process optimization are put forward. The research ideas, methods and results of this project can guide other sites to carry out emulsified oil increment control and emulsified oil treatment.

References Chen S, Tang F, Tian W et al (2020) Research and application of a new demulsifier for the processing of produced liquid in Chanqing gasfield. Mater Sci Forum 991:166–171 Dong Z, Luo T, Lin M (2013) The influences of solid particles on O/W emulsion stability. J Petrochemical Univ 6:55–60 Dong J, Wang Z, Mao Y et al (2018) Study on the detection and removal methods of sulfide in oilfield wastewater. Sci Technol Environ Prot 24(03):1–5 Li F, Li M, Cui J et al (2014) Routine detection of numb-taste (amide) content in Zanthoxylum bungeanum. Forest Guard Sci 50(02):121–126 Luo W, Zhao Y, Lin M et al (2009) The influence of solid particles on the properties of oil-water interfaces and the stability of emulsions. Appl Chem Eng 38(4):483–486 Mukherjee B, Turner J, Wrenn BA (2011) Effect of oil composition on chemical dispersion of crude oil. Environ Eng Sci 28(7):497–506 National Standard GB/T 6533-2012 (2012) Determination of water and precipitate in crude oilcentrifugal method Zhang W, Li M, Yao C et al (2012) Study on the influence of solid particles on the stability of O/ W emulsions. Petrol Geol Develop Daqing 27(4):103–105 Zhou C, Xiao Y, Zhang B (2011) Research progress on domestic chemical enhanced oil recovery (EOR) technologies. Daily Chem Ind 41(2):131–135 Zhu W (2007) Research progress in methods and technologies for oilfield wastewater treatment. Environ Eng 25(5):40–43

Chapter 29

Transit Mental and Their Complexes Catalyzed Oxidative Degradation of Guar Gum by H2 O2 Gao Rongsheng, Cao Yiping, Zhang Xianghui, Liu Qi, Liu Yifan, and Wu Lanbing

Abstract This paper mainly studied the efficiency of Fe(III), Co(II), Ni(II), Cu(II) and their complexes as catalysts in the oxidative degradation of hydroxyethyl guar gum by H2 O2 . The experiment results showed: four kinds of metal ions all can catalyze the oxidation of hydroxyethyl guar gum by H2 O2 , and the system of H2 O2 : FeCl3 = 5: 1 (molar ratio) is the best one. The catalytic performance ranking of three kinds of iron ion complexes on H2 O2 is FeL1 , FeL2 , FeL3 . Compared with metal ions under the same concentration, using L1 as ligand, the catalytic performance that four kinds of complexes FeL1 , CoL1 , NiL1 , CuL1 on H2 O2 have increased in different rate, the amount of the catalyst has been decreased significantly. Besides, the catalytic performance as like as “biomimetic”, CuL1 presented the best catalytic performance on H2 O2 , and the viscosity of hydroxyethyl guar gum solution can be decreased to the lowest 0.0904 dL g−1 in the system of H2 O2 : CuL1 = 20: 1 (molar ratio). Keywords Hydrogen peroxide · Catalytic oxidation · Transition metal complex · Hydroxyethyl guar gum

G. Rongsheng · C. Yiping · Z. Xianghui · L. Yifan Shanxi Yanchang Petroleum Fracturing Material Co., Ltd, Weinan 715500, Shaanxi, China L. Qi · W. Lanbing (B) Xi’an Alberta Resources & Environment Analysis and Testing Technology Co., Ltd., Xi’an 710000, China e-mail: [email protected] W. Lanbing Shaanxi University, Engineering Research Center of Oil and Gas Field Chemistry, Xi’an ShiyouUniversity, Xi’an 710065, China © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_29

357

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29.1 Introduction Guar gum is a natural polymeric plant gum with good water solubility and thickening effect, which is commonly used in the fracturing process of tertiary oil recovery in various oil fields at home and abroad (Ma 2021). However, guar gum-based fracturing waste fluid has high viscosity and complex composition, which makes waste fluid treatment difficult and improper treatment will cause pollution to the surrounding environment, crops, and surface water system (Ma 2021). H2 O2 is a green oxidant with wide adaptability and has wide applications in textile industry, paper industry, medicine and hygiene, beauty care, and metal plating, etc. In recent years, it has also been used in oilfield wastewater treatment. Applications, Wang Liwei et al. (Zhou et al. 2021) studied its degradation of low molecular weight guar, Wan Liping et al. (Li et al. 2021) studied the harmless treatment of oilfield fracturing fluid. H2 O2 often requires the role of catalysts in the process of use, otherwise ineffective decomposition will occur, increasing the cost of use, the traditional catalysts are iron, cobalt, nickel, copper and other transition metal ions, but their general use is too large, the catalytic efficiency is slow, so there is a need to synthesize more efficient catalysts are needed. Fenton reagent is a reagent that uses Fe(II) as a catalyst for chemical oxidation using H2 O2 , which can generate hydroxyl radicals with strong oxidizing properties and generate organic radicals in aqueous solution with difficult to degrade organic substances to destroy their structure and finally oxidize and decompose.. The end products of guar gum oxidation in this system are CO2 and H2 O, and the excess H2 O2 will also be decomposed into H2 O and O2 eventually, which will not cause secondary pollution, so this system is a clean oxidation system. However, the activity of simple Fenton reagent is still relatively low, and the external conditions have a great influence on it, especially the influence of catalyst is most obvious. Catalase is an enzyme widely present in all kinds of organisms and has efficient and specific characteristics for the catalysis of H2 O2 , but due to the physiological activity of the enzyme, the conditions of use are narrow and limited in large-scale use. Therefore, we prepared several metal ion complex catalysts to catalyze the oxidative degradation of H2 O2 by hydroxyethyl guar, with a view to mimicking the excellent properties of peroxidase and enabling its better application in the field of oilfield waste liquid treatment. In this paper, several metal salts as well as several metal ion complexes were examined for their catalytic efficacy as catalysts to catalyze the oxidative degradation of hydroxyethyl guar gum by H2 O2 .

29 Transit Mental and Their Complexes Catalyzed Oxidative Degradation …

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29.2 Materials and Methods 29.2.1 Raw Materials and Instruments FeCl3 ·6H2 O, CoAc2 ·4H2 O, NiCl2 ·6H2 O, CuCl2 ·2H2 O, H2 O2 (mass fraction 30%) are analytically pure, metal ion complexes (FeL1 , FeL2 , FeL3 , CuL1 , NiL1 , CoL1 ) are homemade, hydroxyethyl guar gum is provided by an oil field; urethane viscometer, constant temperature water bath, stopwatch.

29.2.2 Experimental Principle The viscosity of a polymer solution is determined using the capillary method and is obtained by detecting the time required for a certain volume of liquid to flow through a capillary of a certain length and radius. The limiting viscosity [η], expressed in dL/g, is calculated according to the following formula. √ 2(ηsp − ln ηr ) [η] = c / / / 2[(t1 t0 − 1) − ln(t1 t0 )] = c

(29.1)

0) ; ηr is the relative viscosity, tt01 ; c where: ηsp is the incremental viscosity, ηsp = (t1 −t t0 is the value of the concentration of the test solution, g/dL; t1 is the value of the time that the test solution flows through the viscometer timing scale E, F, s; t0 is the value of the time that the distilled water flows through the viscometer timing scale E, F, s.

29.2.3 Experimental Method Prepare a 0.6% solution of hydroxyethyl guar, seal it and leave it at room temperature for four h to make it fully swollen. Add 10 mL of the above swollen hydroxyethyl guar solution to the beaker, then add 10% of the mass fraction of hydroxyethyl guar H2 O2 and a certain amount of catalyst, supplement distilled water to make the total volume of the solution reach 20 mL, stir well and pour it into the Usher viscometer, in a constant temperature water bath at 30°C, use a stopwatch to measure the time required for the glue to flow through the capillary tube in the Usher viscometer, and calculate according to Eq. (29.1) The viscosity of the glue.

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G. Rongsheng et al.

29.3 Results and Discussion 29.3.1 Degradation of Hydroxyethyl Guar Gum by Metal Ion-Catalyzed H2 O2 According to the experimental method in 1.3, the transition metal salts were used as catalysts, and the ratio of the substance of H2 O2 to catalyst was 20:1, 10:1 and 5:1, respectively, to degrade the guar gum solution, and the results are shown in Fig. 29.1. From Fig. 29.1, it can be seen that the catalytic effect of FeCl3 on H2 O2 showed an obvious positive correlation with the amount of FeCl3 added, and the oxidative degradation efficiency and rate of H2 O2 on hydroxyethyl guajava gum increased substantially with the increase of catalyst addition, and when H2 O2 :FeCl3 = 5:1, the viscosity of hydroxyethyl guajava gum solution was already close to that of water at 12 min. The main mechanism of this catalytic reaction may be shown as follows. Fe3+ + H2 O2 → Fe2+ + HO2 + H+

(29.2)

Fe2+ + H2 O2 → Fe3+ + OH− + HO

(29.3)

The generated hydroxyl radical HO· is strongly oxidizing, with an oxidation potential of 2.73 V (Tang et al. 2021), which can damage the mannose linked by β-1,4-glycosidic bonds and galactose linked by α-1,6-glycosidic bonds in the main 2.5

Relative viscosity/dL.g-1

2.0

10% H2O2 H2O2:FeCl3=20:1 1.5

H2O2:FeCl3=10:1 H2O2:FeCl3=5:1

1.0

0.5

0.0

0

50

100

150

200

T/min Fig. 29.1 Changes in viscosity of hydroxyethyl guar gum solution catalyzed by FeCl3

29 Transit Mental and Their Complexes Catalyzed Oxidative Degradation …

361

2.5

Relative viscosity/dL.g-1

2.0

10% H2O2 H2O2:CuCl2=10:1 1.5

H2O2:CuCl2=20:1 H2O2:CuCl2=5:1

1.0

0.5

0.0

0

50

100

150

200

T/min Fig. 29.2 Changes in viscosity of hydroxyethyl guar gum solution catalyzed by CuCl2

chain of the hydroxyethyl guar gum molecule, thus breaking its molecular chain and rapidly reducing the polymer viscosity (Xu et al. 2021a, b). From Fig. 29.2, it can be seen that the oxidative degradation rate of H2 O2 on hydroxyethyl guar increased significantly after adding CuCl2 , and the oxidative degradation effect of the two systems of H2 O2 :CuCl2 = 10:1 and 20:1 on hydroxyethyl guar was not much different, and the oxidative degradation effect of H2 O2 :CuCl2 = 5:1 system on hydroxyethyl guar was the best, and the viscosity of the gum dropped to the lowest at 80 min, which was 0.2823 dL g−1 . As seen from Fig. 29.3, NiCl2 has a certain catalytic effect on the oxidative degradation of hydroxyethyl guar gum by H2 O2 , and the degradation effect is enhanced with the increase of catalyst dosage. The possible reason is that when the content of Ni(II) in the solution is low, with the increase of Ni(II) concentration, the hydroxyl radical HO· generated per unit amount of H2 O2 increases, and the majority of the generated hydroxyl radical HO· is involved in the However, when the content of Ni(II) continued to increase, it reduced H2 O2 and HO· and oxidized itself to highvalent ions, and part of H2 O2 decomposed ineffectively and released oxygen, which made the oxidative degradation efficiency and rate of H2 O2 on hydroxyethyl guajava gum reduced. the oxidative degradation ability of H2 O2 :NiCl2 = 5:1 system was the strongest. It can be seen from Fig. 29.4 that the oxidative degradation rate and efficiency of H2 O2 on hydroxyethyl guar increased substantially with the increase of CoAc2 catalyst addition, and the best oxidative degradation effect was achieved when H2 O2 :CoAc2 = 5:1, and the solution viscosity was 0.3493 dL g−1 at 120 min. From Fig. 29.1-figure supplement 4, it can be seen that all four metal salts have certain

362

G. Rongsheng et al. 2.5

Relative viscosity/dL.g-1

2.0

1.5

1.0

10% H2O2 H2O2:NiCl2=10:1 H2O2:NiCl2=20:1

0.5

H2O2:NiCl2=5:1 0.0

0

50

100

150

200

250

300

T/min Fig. 29.3 Changes in viscosity of hydroxyethyl guar gum solution catalyzed by NiCl2

catalytic effect on H2 O2 . The catalytic effect of trivalent iron ion Fe(III) is the best, followed by divalent copper ion Cu(II), but the dosage of both is too large, and the catalytic efficiency needs to be further improved. 2.5

Relative viscosity/dL.g-1

2.0

10% H2O2 H2O2:CoAc2=10:1 H2O2:CoAc2=20:1

1.5

H2O2:CoAc2=5:1 1.0

0.5

0.0

0

50

100

150

200

250

T/min Fig. 29.4 Changes in viscosity of hydroxyethyl guar gum solution catalyzed by CoAc2

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29.3.2 Degradation of Hydroxyethyl Guar by H2 O2 Catalyzed by Iron Ion Complexes Although the results show that the catalytic effect of iron ions is significant, there is a disadvantage that the range of application is small, and it must be used under acidic conditions (pH < 2.78), and the increase of pH will lead to the precipitation of iron ions, so it cannot be used under high pH or even alkaline conditions, and there is a need to explore catalysts with good catalytic effect and a wider range of pH application. Following the experimental method in 1.3, the ratio of H2 O2 to the amount of substance of each of the three Fe(III) complexes (FeL1, FeL2, and FeL3) was added to 20:1, and the results are shown in Fig. 29.5. From Fig. 29.5, it can be seen that the catalyst has a better catalytic effect when H2 O2 :Fe(III) complex = 20:1 compared to adding only H2 O2 , where FeL1 has the best catalytic effect and the viscosity of the system solution drops to a minimum of 0.4424 dL g−1 at 120 min under the same conditions. The catalytic effect of this class of Fe(III) complexes on H2 O2 is similar to that of the Fenton system with a possible catalytic reaction mechanism (Zhang et al. 2021). Fe2+ + H2 O2 → Fe3+ + OH + OH−

(29.4)

Ea = 39.5 kJ/mol, k1 = 76L/(mol s) Fe3+ + H2 O2 → Fe2+ + HO2 + H+ Ea = 126.0 kJ/mol, k2 = 0.001 − 0.010L/(mol s)

(29.5)

2.5

Relative viscosity/dL.g-1

2.0

10% H2O2 H2O2:FeL3=20:1 H2O2:FeL1=20:1

1.5

H2O2:FeL2=20:1 1.0

0.5

0.0

0

50

100

150

200

250

T/min Fig. 29.5 Changes in viscosity of hydroxyethyl guar gum mastic catalyzed by Fe(III) complexes

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G. Rongsheng et al.

Fe2+ + HO2 → Fe3+ + HO− 2 Ea = 42.0 kJ/mol, k3 = 1.3 × 106 L/(mol s) Fe3+ + HO2 → Fe2+ + O2 + H+ Ea = 33.0 kJ/mol, k3 = 1.2 × 106 L/(mol s) OH + H2 O2 → H2 O + HO2 Ea = 14.0 kJ/mol, k3 = 2.7 × 107 L/(mol s)

(29.6)

(29.7)

(29.8)

This shows that the Fenton-like system has a better oxidative degradation ability for hydroxyethyl guar. In addition, the presence of Fe(III) complexes in ligand form may reduce the activation energy of the reaction between Fe(II) and H2 O2 , which promotes the regeneration of Fe(III) with high catalytic activity, and also generates HO2 · with high activity, which is macroscopically manifested as an efficient oxidative degradation of hydroxyethyl guar. However, the Fenton system is suitable for conditions where the pH is acidic, and the pH of this reaction is close to neutral, which may be the reason why the catalytic effect of the complexes is not substantially improved compared with Fe(III) at the same concentration.

29.3.3 Metal Complex-Catalyzed Degradation of Hydroxyethyl Guar Gum by H2 O2 In order to further optimize the reaction conditions and explore efficient and spectroscopic catalysts, the corresponding complexes were prepared by homemade ligands with Co(II), Ni(II) and Cu(II), i.e., “seeming enzymes”, in order to mimic the catalytic effect of catalase on H2 O2 and make it more catalytic for the oxidative degradation of hydroxyethyl guar. The ligand was used as a ligand for the preparation of other ligands. L1 was used as the ligand for the preparation of other metal ion complexes, and their performance in catalytic degradation of hydroxyethyl guar gum by H2 O2 was evaluated according to the experimental method in 1.3. The ratio of H2 O2 to several complexes was 20:1, and the results are shown in Fig. 29.5. As can be seen from Fig. 29.6, the catalytic effect of several complexes on H2 O2 was substantially improved over the corresponding metal ions at the same concentration. When H2 O2 :metal ion complex = 20:1, the catalytic effect of Fe(III), Co(II) and Ni(II) complexes was similar, and the rate and efficiency of oxidative degradation of hydroxyethyl guar by H2 O2 were similar, while the catalytic effect of Cu(II) complex was better than the first three, and the solution viscosity reached the lowest after 50 min, which was 0.0904 dL g−1 . The catalytic effect of this class of complexes may be similar to that of catalase, i.e., it has a “mimicking” effect (Tang et al. 2020). Patel et al. suggested that the peroxidase is converted to an active enzyme upon interaction with H2 O2 , which then interacts with the substrate to produce the product (Zhou 2020). Reedijk et al. showed

29 Transit Mental and Their Complexes Catalyzed Oxidative Degradation …

365

3.0

Relative viscosity/dL.g-1

2.5

2.0 10% H2O2 H2O2:CoL1=20:1 H2O2:NiL1=20:1 H2O2:FeL1=20:1 H2O2:CuL1=20:1

1.5

1.0

0.5

0.0

0

50

100

150

200

T/min Fig. 29.6 Changes in viscosity of hydroxyethyl guar gum solution under the catalytic action of the complex

that in this type of reaction the complexes catalyze the redox reaction by reacting the active complex with the substrate to finally produce the product (Tang et al. 2019). The main kinetic feature of this reaction is the formation of an intermediate complex by a reversible reaction between the catalyst and the substrate before the decisive step occurs, i.e., the reactive catalyst first reacts with the substrate through a reversible reaction to form an intermediate complex, which then passes through a decisive step to form the product, while the catalyst is reduced. Based on previous studies, a ternary complex model for the oxidative degradation of hydroxyethyl guar by H2 O2 catalyzed by metal complexes was proposed. It is assumed that the metal complex MLn firstly becomes the active species M * Ln rapidly after the interaction with the oxidant H2 O2 , then it combines with the substrate S to form the ternary complex M * LnS, and finally the ternary complex M * LnS decomposes to form the product P, while the active species M * Ln is reduced to the initial state, which is the decisive step of the reaction. The reaction of H2 O2 oxidative degradation of hydroxyethyl guar is transformed into an intramolecular electron transfer reaction, which reduces the activation energy of the reaction and increases both the reaction rate and efficiency. The whole reaction process can be expressed as follows. where Ks is the oxidation active state binding constant for the substrate and the complex; KN is the primary rate constant for the generation of the product from the ternary complex in the decisive step; and Kreox is the apparent rate constant for the non-catalytic reaction of the substrate S with H2 O2 in aqueous solution (Tang et al. 2019).

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29.4 Conclusion Fe(III), Co(II), Ni(II), and Cu(II) salts all have certain catalytic effects on the oxidative degradation of hydroxyethyl guar by H2 O2 , among which Fe(III) has the best catalytic performance, but its dosage is larger. Compared with metal ions, the catalytic efficiency of homemade “seeming enzyme” for hydrogen peroxide was substantially improved, and the dosage was less, among which CuL1 had the best catalytic effect. Acknowledgements This work was financially supported by grants from Youth Innovation Team of Shaanxi University, Shaanxi Key Research and Development Plan (2023-YBGY-052) and Key Scientific Research Project of Shaanxi Provincial Department of Education (21JY035).

References Li Z, Zhang J, Qu C, Tang Y, Slaný M (2021) Synthesis of Mg-Al hydrotalcite clay with high adsorption capacity. Materials 14:7231 Ma L, Xue Y, Du W, Qu C, Zhang J, Chen G (2021) Catalytic oxidation of polymer used in oilfield by a bentonite supported Cu(II) complexes in a wide pH range. Desalin Water Treat 229:314–321 Tang Y, Ren H, Yang P, Li H, Zhang J, Qu C, Chen G (2019) Treatment of fracturing fluid waste by Fenton reaction using transition metal complexes catalyzes oxidation of hydroxypropyl guar gum at high pH. Environ Chem Lett 17:559–564 Tang Y, Zhou L, Xue Y, Gu X, Zhang J, Qu C (2020) Preparation of nanoscale zero-valent metal for catalyzed clean oxidation of hydroxypropyl guar gum at neutral pH value. Desalin Water Treat 197:328–334 Tang Y, Zhou L, Xu Z, Zhang J, Qu C (2021) Heterogeneous degradation of oil field additives by Cu(II) complex-activated persulfate oxidation. Environ Progress Sustain Energy 40(3):e13562 Xu Z, Dong J, Liu Y, Zhang J, Qu C, Tang Y (2021a) Oxidation of sulfur ions in oilfield wastewater by montmorillonite loaded Mn-catalyzed hydrogen peroxide oxidation. Desalin Water Treatment 230:219–226 Xu Z, Xue Y, Zhang J, Tang Y (2021b) Bentonite-supported zero metal for catalyzed clean oxidation of hydroxypropyl guar gum at neutral pH value. Fresenius Environ Bull 30:9044–9053 Zhang J, Liu X, Li Y, Chang X, Zhang J, Chen G (2021) Study of COD removal from the waste drilling fluid and application in Chad oilfield. J Water Chem Technol 43(1):60–67 Zhou L, Xu Z, Zhang J, Zhang Z, Tang Y (2020) Effective degradation of hydroxypropyl guar gum at wide pH range by heterogeneous Fenton-like using supported zero-valent copper. Water Sci Technol 82:1635–1642 Zhou L, Slaný M, Bai B, Du W, Qu C, Zhang J, Tang Y (2021) Enhanced removal of sulfonated lignite from oil wastewater with multidimensional MgAl-LDH nanoparticles. Nanomaterials 11:861

Chapter 30

Prediction of Eco-Economic-Social Coordinated Development Based on Artificial Neural Network (ANN) Model: A Case Study of Qinling Area of Giant Panda National Park Yan Gao, Zongxing Li, and Qi Feng

Abstract In this paper, the coordinated development of three subsystems of ecology, economy and society in Qinling area of Giant Panda National Park (GPNP) is studied, and the prediction model of coordination degree is established based on artificial neural network (ANN) model. The results show that the coordination degree of the three subsystems has been improved steadily during 2012–2021. The state of development was upgraded from a mild disorder decline type to high quality coordinated development type. National parks play an important role in protecting local ecological environment and promoting economic and social development. The ANN model is used to establish a prediction model of the coordination degree of the three subsystems. It is verified that the mean absolute error (MAPE) and correlation coefficient (R) of the prediction model are 1.45% and 0.956, respectively, which indicates the accuracy of the ANN prediction model. Keywords Coordination development · ANN · Giant Panda National Park

30.1 Introduction The National park is a special area with clear boundaries, which is used to protect the natural ecosystem with characteristics in order to achieve scientific protection and rational use of natural resources (Peng et al. 2021). The national park is a kind of protected area, which is used by most countries and regions in the world (Han Y. Gao (B) Shaanxi University of Chinese Medicine, Xi’an 712046, China e-mail: [email protected] Z. Li · Q. Feng Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_30

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et al. 2021). It provides a sustainable development model, taking into account the interests of all parties, so that the conservation area can be long-term and sustainable development (Tan et al. 2021). Yellowstone National Park is the earliest national park in the world (Halstead et al. 2002), and its management model provided a model for ecosystem protection and was followed by many countries. In order to better protect China’s ecological environment, China has actively developed national parks. The Giant panda National Park (GPNP), which was established in January 2017, covers Shaanxi, Sichuan and Gansu provinces and aims to protect the biodiversity of the giant panda as the core, while taking into account local ecological and environmental protection, regional economic development, community development and scientific and educational publicity. The Qinling Mountains is located in the North–South boundary of China, with rich plant resources, wildlife resources, landscape resources and cultural resources. Its ecological environment and future development will have an important impact on the national ecological protection, climate change, social and economic development (He et al. 2021). Hence, it is very meaningful to explore the sustainable development mode of the Qinling area with the GPNP as the carrier. The national park contains rich natural and cultural resources. It is not only a nature reserve, but a complex of ecological protection, tourism development, cultural communication and economic development. While effectively protecting the ecological environment, it should also promote development of economic and social. It is necessary to conduct a comprehensive analysis of the coordinated development of ecology, society and economy for the national park in order to maintain its good development. Coordinated development in different fields has been widely studied, including urbanization (Fang et al. 2021), industrialization (Hou et al. 2021), ecological environment (Meng et al. 2022; Kong et al. 2023), etc. Research on the coordinated development of the study area can help us understand the development status of the study area, find the existing problems, and put forward specific suggestions and countermeasures. However, a more comprehensive model is needed to reasonably forecast its development for a more comprehensive understanding. Artificial neural network (ANN) model is an effective tool for the complex question (Xu et al. 2014), and it has been widely applied to establish model and make a forecast (Singh et al. 2009; Iqbal et al. 2023). Based on the statistical data of Qinling area of GPNP from 2012 to 2021, this work will analyze the coordinated development status of its ecological, social, economic subsystems, and uses the ANN model to establish prediction model. The study will provide decision-making basis and data support for the development of the GPNP.

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Table 30.1 The index system of ecological subsystem, economic subsystem and social subsystem in Qinling area of GPNP Subsystems

Index

Attribute

Ecology subsystem

Sulfur dioxide emissions, total industrial waste gas emissions, Negative household garbage removal volume, industrial wastewater emissions, total industrial water consumption, total annual water supply, industrial solid waste production, smoke (powder) dust emissions

Economy subsystem

GDP, Per capita GDP, GDP of primary industry, GDP of secondary Positive industry, per capita disposable income of permanent urban residents, GDP of tertiary industry, retail sales of consumer goods, per capita disposable income of rural residents

Society subsystem

Ratio of students to schools in primary school, ratio of students to Positive schools in secondary school, number of cultural centers, number of beds in health institutions, permanent resident population, number of health institutions, proportion of urban population, number of health technicians

30.2 Research Methods and Data Processing 30.2.1 Establishment of Index System According to the characteristics of Qinling area of GPNP, 24 indicators are selected to evaluate the coordinated development of eco-economic-social system (Table 30.1). According to relevant literature reports and published statistical data, the selected indicators should be true, comprehensive and objective. In addition, these indicators can fully reflect the real state and development trend of ecological subsystem, economic subsystem and social subsystem.

30.2.2 Data Sources and Research Methods In this paper, the Qinling area of GPNP is taken as the research object. The data of each index are mainly from the statistical data published by Shaanxi Statistical Yearbook (2012–2021), China Rural Statistical Yearbook (2012–2021), the official website of the GPNP Administration and other national and local governments. Application of entropy method should eliminate the unit differences among indicators. In this work, the deviation standardization method is applied to process data. After processing, the data are dimensionless value. The standardized processing equations of positive and negative indicators are Eqs. (30.1) and (30.2) respectively. Y=

X i − X min X max − X min

(30.1)

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Y=

X max − X i X max − X min

(30.2)

In which Y is normalized values, Xi is statistics, Xmax is maximum values in statistics, Xmin is minimum values in statistics. After calculating the standardized value, the weight of each index is calculated by entropy weight method. The Yij is set as be the dimensionless value of each index, where j is the index number and i is the sample number. Firstly, the weight of the ith sample index of the jth index is calculated (Zij ). Then, the entropy value of the jth index is calculated (Sj ). The information utility value of the index is calculated (Fj ). Finally, the weight of the jth index is calculated (Rj ). The weights of ecological, economic and social subsystems are calculated by the entropy weight method in this work. Z ij = Yi j /

n ∑

Yi j

(30.3)

i=1

− Sj =

n ∑

Z i j ln Z i j

i=1

(30.4)

ln n Fj = 1 − Sj

Fj Rj = ∑n 1 +···+n k

j=n 1 +···+n k−1 +1

(30.5)

Fj

(30.6)

30.2.3 Data Sources and Research Methods The ecological subsystem, economic subsystem and social subsystem of the Qinling area of GPNP have a complex relationship. They influence each other and develop harmoniously. This paper will construct the coordination degree model of ecological, economic and social subsystems for revealing the internal relationship among three subsystems and promoting their sustainable development. T1 × T2 × T3 1 ]3 (T1 + T2 + T3 )3 ∑ T = λY

C = 3[

D = (C × R)1/2

(30.7) (30.8) (30.9)

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Table 30.2 Evaluation criteria and types of coordination degree Coordination degree

Coordination type

State

0 ≤ D ≤ 0.09

Extreme disorder decline

Disorder state

0.1 ≤ D ≤ 0.19

Severe disorder decline

0.2 ≤ D ≤ 0.29

Moderate disorder decline

0.3 ≤ D ≤ 0.39

Mild disorder decline

0.4 ≤ D ≤ 0.49

Borderline disorder decline

0.5 ≤ D ≤ 0.59

Grudgingly coordinated development (CD)

0.6 ≤ D ≤ 0.69

Primary CD

0.7 ≤ D ≤ 0.79

Intermediate CD

0.8 ≤ D ≤ 0.89

Well CD

0.9 ≤ D ≤ 1

High quality CD

R = aT1 + bT2 + cT3

Practice state Coordinated state

(30.10)

where C is the coupling degree, T 1 , T 2 and T 3 represent the comprehensive evaluation values of ecological, economic and social subsystem, respectively. The λ is the weight of each index, and Y is the standardized value of each index. The comprehensive evaluation values of the subsystems can be obtained by putting the weights and standardized values of each index into the Eq. (30.7). The D is the coordination degree, R is the comprehensive coordination index among subsystems, a, b and c are coordination coefficients, which are respectively taken as 0.4, 0.3 and 0.3 according to experience. Table 30.2 shows the types of coordination degree D.

30.3 Results and Discussion 30.3.1 Analysis of Coordination Degree Table 30.3 shows the coordination degree and coordinated development types of ecological, economic and social subsystems in Qinling area of GPNP from 2012 to 2021. In order to more intuitively observe the changing of D with years, the changing curve of coordination degree with years is drawn in Fig. 30.1. On the whole, the coordination degree of ecological, economic and social subsystems within the research range showed a trend of gradual increase. In 2012, the coordination degree of the three subsystems was 0.316, at which time the three subsystems were in the type of mild disorder decline. This shows that the ecological, economic and social development of the Qinling area of GPNP is not coordinated in 2012. During this period, the local government and people had a weak awareness of environmental protection and often exchanged short-term economic benefits at the cost of destroying the ecological environment. However,

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Table 30.3 Coordination degree and the types of coordination development of ecological, economic and social subsystems Years

D

Coordination type

2012

0.316

Mild disorder decline

2013

0.504

Grudgingly coordinated development (CD)

2014

0.581

Grudgingly CD

2015

0.640

Primary CD

2016

0.672

Primary CD

2017

0.759

Intermediate CD

2018

0.803

Well CD

2019

0.785

Intermediate CD

2020

0.878

Well CD

2021

0.923

High quality CD

Fig. 30.1 Changing of coordination degree with years

such short-term profit cannot be exchanged for sustainable economic and social development. After that, the state of coordinated development gradually improved. By 2013, the coordination degree of the three subsystems was increased to 0.504, and the state of coordinated development changed to the type of grudgingly coordinated development. The three subsystems began to develop reluctantly and harmoniously through running-in, which was maintained until 2014. During this period, Chinese governments at all levels began to attach importance to environmental and ecological protection, and relevant policies were issued one after another. The state incorporated ecological civilization construction into the overall plan of the cause of socialism with Chinese characteristics and made comprehensive arrangements for ecological civilization construction. In 2015, the coordinated development type of ecological, economic and social systems in the Qinling area of the GPNP was transformed into

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primary coordinated development, which was maintained until 2016. In 2017, the coordinated development type of the three subsystems was further improved, and the development status changed to intermediate coordinated development. In 2018, the type of coordinated development was further adjusted to well coordinated development. However, due to the uncertainty of the implementation of the policy, the development state of the study area also has corresponding fluctuations. In 2019, the type of coordinated development reverted to intermediate coordinated development, the same as in 2017. In 2020, the state of development was readjusted to well coordinated development. By 2021, the state of development will be transformed into high quality coordinated development. The changes of coordinated development types of ecology, economy and society in Qinling area of GPNP not only show that the implementation of relevant policies is very effective, but also reflect the progress of local people’s ideological and cultural level. The implementation of good policies needs to have a mass base, and only policies recognized by the public can be effectively implemented.

30.3.2 ANN Model Construction and Verification The ANN model should contain input layer, hidden layer and output layer (Sun et al. 2011). The processing units of each layer are connected to each other, but the units of the same layer are independent of each other. The input layer of this paper contains three parts: the standardized values of ecological subsystem, social subsystem and economic subsystem, and the output value is the coordination degree. The hidden layer in the middle is to establish the relationships between the three input factors and the output value. The neural network structure is shown in Fig. 30.2. In order to enable the ANN model to have the predictive ability, it is trained with the experimental sample value, so that the ANN can realize the mapping relationship from the given input value to the output value. Inverse propagation of errors is the core of the ANN model established in this paper. The model minimizes errors through continuous learning and adjustment. Activation functions of the hidden layer and the output layer are respectively selected as log-sigmoid function of log-S-type and hyperbolic tangent S-type tansigmoid function (Zhu et al. 2011). Specific expressions are shown as follows: tan sig(x) =

2 −1 1 − e−2x

R P0.2 = 129.34 f + 1059.65

(30.11) (30.12)

As a rule of thumb, the minimum error margin is set at 0.01, the LM (Levenberg– Marquardt) algorithm was selected as the optimization algorithm (Zhu et al. 2011). In order to make the experimental sample values conform to the requirements of the ANN model, the input values and output values need to be normalized so that all

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Fig. 30.2 The architecture of the ANN model

values are located in the interval [0, 1]. Zi =

Z − 0.95Z min 1.05Z max − 0.95Z min

(30.13)

In which, Z i is the normalized value after processing, Z is the original value, and Z max and Z min respectively represent the maximum and minimum values in the data sample. The algorithm implementation of the ANN model can be roughly divided into the following steps: Firstly, network initialization is carried out, and initial values of weights and thresholds are set. Secondly, the sample values used for training are input into the network model. Third, the ANN model outputs the calculated value and compares it with the measured value to find the difference between the two. Then, according to the direction of error back propagation, the weight is adjusted based on the deviation. Finally, the calculated value is re-output using the adjusted weight and compared to the expected value, repeating until the error is reached. To better evaluate the predictive ability, correlation coefficient (R) and mean absolute error (MAPE) were selected as evaluation indicator to measure the performance of the ANN model. | N | 1 ∑ || E i − Pi || × 100 M A P E(%) = N i=1 | E i |

(30.14)

∑N

(E i − E)(Pi − P) ∑N 2 2 i=1 (E i − E) i=1 (Pi − P)

R = /∑ N

i=1

(30.15)

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Fig. 30.3 Comparison between predicted and measured values

in which, E is the experimental data, P is the predicted value, N is the total number of experimental samples, E and P are the average value of experimental data E and predicted value P respectively. According to the above parameter setting, the number of target iteration steps is set as 10,000, and the ANN model is trained repeatedly. Finally, the ideal target accuracy can be achieved. Figure 30.3 is the comparison between the predicted values and measured values. The closer the data points of the two curves are, the closer the predicted value is to the experimental value. The MAPE and R are 1.45% and 0.956, respectively, which verifies that the ANN model has good predictive power.

30.4 Conclusions Based on statistical data, this paper studies the sustainable development status of Qinling area of GPNP, and establishes a prediction model of coordinated development of Qinling area of GPNP based on the ANN model. The main conclusions are as follows: 1. The coordination degree of ecological, economic and social subsystems in Qinling area of GPNP has been steadily improved. From the time sequence of coordination degree, it was in the stage of mild disordered decline in 2012, rose to the stage of grudgingly coordinated development in 2013, and then continued to improve until it reached the stage of high quality coordinated development in 2021. 2. The coordination degree of ecology, economy and society subsystems in the Qinling area of the GPNP is positively correlated with the sound development track of each subsystem. The national park plays an important role in

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protecting the local ecological environment and promoting economic and social development. 3. The coordination degree prediction model based on the ANN model has good predictability. Acknowledgements This work is supported by Natural Science Foundation of Shaanxi Province, China (No. 2022JQ-284), Scientific Research Project of Shaanxi University of Chinese Medicine (2021GP37), Shaanxi Province “the 14th Five-Year Plan” Educational Science Planning Project (SGH22Q251), Teacher Education and Teacher Development Research Project of Shaanxi University of Chinese Medicine (2022JSFZ4), Innovation and Entrepreneurship Education Research Association of National Higher Education Association of Traditional Chinese Medicine 2022 Annual Innovation and Entrepreneurship Education project (zyycxcy2022032), Open Foundation of Qilian Mountain Center (NO. QLS202005).

References Fang X, Shi XY, Phillips TK et al (2021) The coupling coordinated development of urban environment towards sustainable urbanization: an empirical study of Shandong Peninsula, China. Ecol Ind 129:107864 Halstead BJ, Ray AM, Muths E et al (2002) Looking ahead, guided by the past: the role of U.S. national parks in amphibian research and conservation. Ecol Indic 136:108631 Han H, Guo L, Zhang JQ (2021) Spatiotemporal analysis of the coordination of economic development, resource utilization, and environmental quality in the Beijing-Tianjin-Hebei urban agglomeration. Ecol Ind 127:107724 He Y, Hu YY, Song JX et al (2021) Variation of runoff between southern and northern China and their attribution in the Qinling Mountains, China. Ecol Eng 171:106374 Hou R, Li SS, Chen HY et al (2021) Coupling mechanism and development prospect of innovative ecosystem of clean energy in smart agriculture based on blockchain. J Clean Prod 319:128466 Iqbal J, Tyagi A, Jain M (2023) Artificial neural network based modeling of liquid membranes for separation of dysprosium 41(03):440–445 Kong I, Sarmiento FO, Mu L (2023) Crowdsourced text analysis to characterize the U.S. National Parks based on cultural ecosystem services. Landscape Urban Plann 233:104692 Meng JD, Long Y, Shi LF (2022) Stakeholders’ evolutionary relationship analysis of China’s national park ecotourism development. J Environ Manage 316:115188 Peng DM, Mu YT, Zhu YG (2021) Evaluating the level of coordinated development of fisheries economic growth and environmental quality in selected Chinese regions. Environ Impact Assess Rev 89:6605–6605 Singh KP, Basant A, Malik A et al (2009) Artificial neural network modeling of the river water quality-a case study. Ecol Model 220(6):888–895 Sun Y, Zeng WD, Han YF et al (2011) Modeling the correlation between microstructure and the properties of the Ti-6Al-4V alloy based on an artificial neural network. Mater Sci Eng, A 528:8757–8764 Tan S, Zhong YD, Yang F et al (2021) The impact of Nanshan National Park concession policy on farmers’ income in China. Glob Ecol Conserv 31:e01804 Xu JW, Zeng WD, Jia ZQ et al (2014) Prediction of static globularization of Ti-17 alloy with starting lamellar microstructure during heat treatment. Comput Mater Sci 92:224–230 Zhu YC, Zeng WD, Sun Y et al (2011) Artificial neural network approach to predict the flow stress in the isothermal compression of as-cast TC21 titanium alloy. Comput Mater Sci 50:1785–1790

Chapter 31

Enhancement of Natural Iron-Bearing Mineral on Microbial Reduction of Hexavalent Chromium Xinglan Cui, Hongxia Li, Peng Zheng, Lei Wang, and Xinyue Shi

Abstract Natural iron-bearing mineral can promote the extracellular electron transfer of microorganisms and thus affect the microbial remediation of heavy metals. In this study, the characteristics of natural iron-bearing mineral were analyzed and the enhancement effect of natural iron-bearing mineral with different particle size on microbial reduction of Cr(VI) were determined. The XRD results showed that the main components of iron-bearing materials were magnetite and pyrrhotite. The reduction efficiency of Cr(VI) increased with the increasing addition of iron-bearing mineral in single mineral system. The reduction efficiency of Cr(VI) in mixed mineral and microorganism system reached 88.54%, which was higher than the sum of that of single mineral system and single microorganism system, indicating the enhanced reduction effect of iron-bearing mineral on chrome-reducing bacteria. The ironbearing mineral with different particle sizes (< 0.0385 mm, 0.0385 – 0.054 mm, 0.054–0.154 mm, 0.074–0.154 mm, > 0.154 mm) presented different enhanced effect on the reduction of Cr(VI) with different concentrations (200–500 mg/L), and > 0.154 mm was determined as the optimal particle size. Keywords Mineral · Enhanced · Microbial · Reduction · Hexavalent chromium

X. Cui (B) · H. Li · P. Zheng · L. Wang · X. Shi The National Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, GRINM Resources and Environmental Technology Corporation Limited, Beijing 101407, China e-mail: [email protected] Beijing Engineering Research Center of Strategic Nonferrous Metals Green Manufacturing Technology, Beijing 100088, China GRIMAT Engineering Institute Corporation Limited, Beijing 100088, China P. Zheng General Research Institute for Nonferrous Metals, Beijing 100088, China © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 H.-Y. Jeon (ed.), Sustainable Development of Water and Environment, Environmental Science and Engineering, https://doi.org/10.1007/978-3-031-42588-2_31

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31.1 Introduction In china, more than 20% of the groundwater is polluted by Cr(VI), most of which is caused by the chromium slag and electroplating sludge piled up for years (Wang et al. 2020). In the natural state, chromium in soil cannot be eliminated, but can enter groundwater or be absorbed by crops and enter the food chain, endangering the health of human body, which is the fundamental reason why chromium has become the most dangerous pollutants in soil and groundwater. Therefore, timely conversion of Cr(VI) into Cr(III) in contaminated soil and groundwater can reduce its toxicity and mobility, which has important practical significance for the protection of soil and groundwater environmental safety (Wang et al. 2022). At present, microbial remediation is becoming the research hotspot because of its no secondary pollution, environmentally friendly, and simple operation (Begum et al. 2022). In general, the microbial remediation of chromium pollution mainly focuses on microbial reduction of Cr(VI) into Cr(III). However, the microbial remediation has a long cycle time and subject to environmental influences, requiring chemical and other means to enhance the microbial remediation effect (Fu et al. 2020; Ma et al. 2019). Currently, iron-based and carbon-based materials are the most widely studied conductive mediators used to enhance microbial activity and remediation efficiency. Among them, natural iron-bearing mineral is cheap and readily available, and also can facilitate extracellular electron transfer from microorganisms and enhance Cr(VI) reduction (Lu et al. 2019). Therefore, iron-bearing mineral was used to enhance the reduction process of Cr(VI) by chromium reducing bacteria in this study, and the main objectives are to (1) determine the characteristics of iron-bearing mineral; (2) explore the effect of proportion of mineral and chromium reducing bacteria on enhanced microbial reduction; (3) analyze the effect of particle size of natural iron-bearing mineral on enhanced microbial reduction. This study will provide an effective method of enhanced microbial remediation for Cr(VI)-contaminated soil and groundwater.

31.2 Methodology 31.2.1 Materials The iron-bearing mineral was obtained from a beneficiation plant in Shanxi province. The chromium reducing bacteria was screened from a chromium contaminated site in Qinghai province. The medium of chromium reducing bacteria contained the following components: glucose, corn pulp dry powder, and inorganic salt.

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31.2.2 Cr(VI) Reduction Experiments The Cr(VI) reduction experiments by iron-bearing mineral and chromium reducing bacteria were conducted in 300 mL conical flasks with 400 mg/L Cr(VI)contaminated water at room temperature. The contents of Cr(VI), total Fe and Fe(II) were measured after reaction for 18 days. The contents of Cr(VI) and Fe(II) were analyzed by ultraviolet and visible spec-trophotometer (UV/VISS). The content of total Fe was determined by Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). The characteristics of iron-bearing mineral was analyzed by X-ray Diffraction (XRD).

31.3 Results and Discussion 31.3.1 Characteristics of Iron-Bearing Mineral The XRD results of the natural iron-bearing mineral were shown in Fig. 31.1. The main components of the mineral were magnetite (Fe3 O4 ) and magnetic pyrite (FeS). Small amount of FeSO4 was found due to the oxidization of the magnetic pyrite after a period of stacking, in which Fe(II) also has reducing ability to Cr(VI). The chemical elemental compositions of natural iron-bearing mineral were shown in Table 31.1. There was over 60% of total Fe in natural iron-bearing mineral, with virtually free of heavy metals. Therefore, the mineral was suitable as a pollution remediation material. Figure 31.2 showed the effect of mineral addition and solution pH on the reduction of Cr(VI) by natural iron-bearing mineral. The reduction efficiency of Cr(VI) Fig. 31.1 The XRD results of the natural iron-bearing mineral

Fe3O4 FeS Fe(SO4) 





natural iron-bearing minerals (0.154 mm)



40

   50 60 2θ (degree)



 70

80

90

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Table 31.1 The chemical elemental composition of natural iron-bearing mineral Fe

Ca

Al

K

Na

60.44

0.74

0.29

0.04

< 0.005

Natural iron-bearing mineral (< 0.0385 mm)

63.33

0.27

0.46

0.051

< 0.006

100

100

80

80

Reduction efficiency(%)

Reduction efficiency(%)

Samples Natural iron-bearing mineral (> 0.154 mm)

60

40

20

60

40

20

0 Control

5

10

15

Mineral addition(g/L)

20

25

0 Control

5

6

7

8

9

pH

Fig. 31.2 The effect of mineral addition and solution pH on the reduction of Cr(VI) by natural iron-bearing mineral

increased with increasing mineral addition, but the overall reduction efficiency was below 40%. It indicated that the reduction efficiency of natural iron-bearing mineral was limited. The reduction efficiency of Cr(VI) by natural iron-bearing mineral varied less with the initial pH of the solution, and the final pH of the reaction system was reduced to about 4.0. Because the mineral itself was acidic and could continuously release H+ into the solution.

31.3.2 Effect of Mineral Proportion on Enhanced Microbial Reduction Effect on physicochemical properties. Figure 31.3 showed the changes in pH and Eh of the mixed mineral and microorganism system with different proportion of iron-bearing mineral and chromium reducing bacteria. The pH of the chromium reducing bacteria reduction systems without mineral remained basically unchanged after the reaction. However, the pH of the iron-bearing mineral and iron-bearing mineral-enhanced microbial reduction systems all increased to about 7.0 after the reaction, indicating that the acidic iron-bearing mineral participated in the reduction of Cr(VI) and its content was reduced. The Eh of all reduction systems (chromium reducing bacteria, iron-bearing mineral, iron-bearing mineral-enhanced microbial)

31 Enhancement of Natural Iron-Bearing Mineral on Microbial Reduction … 500

12 Before After A 5g/L mineral B 5% chromium reducing bacteria

10 8

Before After A 5g/L mineral B 5% chromium reducing bacteria

400

300

6

Eh

pH

381

200

4

100

2

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Fig. 31.3 The changes in pH and Eh of the mixed mineral and microorganism system with differ-ent proportion of iron-bearing mineral and chromium reducing bacteria

all decreased significantly, indicating the occurrence of reduction reaction of Cr(VI) to Cr(III), which lead the systems to relatively reduced state. Effect on reduction efficiency of Cr(VI). Figure 31.4 showed the changes in reduction efficiency of Cr(VI) of the mixed mineral and microorganism system with different proportion of iron-bearing mineral and chromium reducing bacteria. In single mineral system with addition of 5 g/L, the reduction efficiency of Cr(VI) was 13.28%. In single chromium reducing bacteria system with inoculation rate of 5%, the reduction efficiency of Cr(VI) was 5.32%. In the mineral-enhanced microbial system (mineral addition of 5 g/L and microbial inoculation rate of 5%), the reduction efficiency of Cr(VI) was 31.06%, which was higher than the sum of that of single mineral and single microbial systems. This indicated that the iron-bearing mineral enhanced the reduction effect of the chromium reducing bacteria. The reduction efficiency of Cr(VI) of the enhanced systems reached a maximum of 88.54% when the mineral addition was 5 g/L and the inoculation rate of chromium reducing bacteria was 25%. Studies have shown that the addition of Fe(III) also could promote the microbial reduction of Cr(VI) (Wang et al. 2021). The pathway in which Fe(III) was reduced to Fe(II) and then reduce Cr(VI) was more conducive to the growth of microorganism. Because the presence of Fe(III) could decrease the amount of Cr(VI) from the direct reduction reaction of microorganisms, thus alleviating the toxicity of Cr(VI) to microorganisms (Zou et al. 2022; Li et al. 2022). Therefore, the use of iron-bearing mineral to enhance microbial reduction of Cr(VI) might be economical and efficient.

31.3.3 Effect of Particle Size of Natural Iron-Bearing Mineral on Enhanced Microbial Reduction Effect on the reduction efficiency of Cr(VI). Figure 31.5 showed the reduction efficiency of Cr(VI) in solution of the enhanced systems with different particle sizes of iron-bearing mineral. Within the Cr(VI) concentration range of 200 mg/L to 500 mg/

382 100 A B

5g/L mineral 5% chromium reducing bacteria

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Fig. 31.4 The changes in reduction efficiency of Cr(VI) of the mixed mineral and microorganism system with different proportion of iron-bearing mineral and chromium reducing bacteria

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L, the reduction efficiency of Cr(VI) gradually decreased as the Cr(VI) concentration increased. The reduction efficiency of Cr(VI) at low concentrations (200 and 300 mg/ L) were above 90%, and that of Cr(VI) at higher concentrations (400 and 500 mg/L) were more than 50%. Generally, the mineral with largest particle size (> 0.154 mm) and smallest particle size (< 0.0385 mm) were relatively more effective for enhancing microbial reduction of Cr(VI). Among them, > 0.154 mm mineral particle was more efficient and economical. Effect on Fe and Fe(II). Figure 31.6 showed the concentration of Fe and Fe(II) in solution of the enhanced systems with different particle sizes of iron-bearing mineral. Compared with other particle sizes, the highest Fe concentrations were found in the mineral-enhanced systems with largest particle size (> 0.154 mm) and smallest particle size (< 0.0385 mm), which was consistent with the previous results of the reduction efficiency of Cr(VI). This might be due to that the large particle size mineral promoted the growth of chromium reducing bacteria and then promoted the reduction of Fe(III) in the mineral to Fe(II), which entered the solution as Fe(III) after reduction

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Fig. 31.5 The reduction efficiency of Cr(VI) in solution of the enhanced systems with different particle sizes of iron-bearing mineral

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>0.154 mm 0.074~0.154 mm 0.054~0.154 mm 0.0385~0.054 mm 0.154 mm 0.074~0.154 mm 0.054~0.154 mm 0.0385~0.054 mm 0.154 mm 0.074~0.154 mm 0.054~0.154 mm 0.0385~0.054 mm 0.154 mm iron-bearing mineral was determined as the optimal particle size for enhancing the reduction of Cr(VI) by chromium reducing bacteria. Acknowledgements The project was funded by the National Key Research and Development Project (No. 2019YFC1805900).

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