Environmental Management in India: Waste to Wealth 3030938964, 9783030938963

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Shalini Yadav Abdelazim M. Negm Ram Narayan Yadava   Editors

Environmental Management in India: Waste to Wealth

Environmental Management in India: Waste to Wealth

Shalini Yadav · Abdelazim M. Negm · Ram Narayan Yadava Editors

Environmental Management in India: Waste to Wealth

Editors Shalini Yadav Centre of Excellence in Advanced Water and Environmental Research Rabindranath Tagore University Bhopal, Madhya Pradesh, India

Abdelazim M. Negm Faculty of Engineering Water and Water Structures Engineering Department Zagazig University Zagazig, Egypt

Ram Narayan Yadava Research and International Affairs Madhyanchal Professional University Bhopal, Madhya Pradesh, India

ISBN 978-3-030-93896-3 ISBN 978-3-030-93897-0 (eBook) https://doi.org/10.1007/978-3-030-93897-0 © Springer Nature Switzerland AG 2022 This work is subject to copyright. All rights are reserved 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

Preface

The motivation of this volume titled Environment Management: From Waste to Wealth in India is mainly the need to support India and the developing countries to convert waste to wealth. It contains 13 chapters covering various technologies and methodologies to convert waste to wealth. The chapters are divided into five parts. Part I is an introduction to the book and correlates the global SDGs to the Indian context. Part II is titled Waste to Wealth and consists of five chapters. While Part III consists of four chapters under the title From Waste to Energy. On the other hand, Part IV is dealing with Waste to Sustainability and consists of two chapters. The last part is devoted to summarize the conclusions and recommendations of the book in addition to an update of the recent literature. The next para will briefly introduce the 13 chapters of the book to the audiences. The chapter “Waste Management and the Agenda 2030 in the Indian Context” authored by Dr. Ram Boojh discusses the benefits of proper waste management. Agenda 2030 and Sustainable waste management help in increasing the social, economic, and environmental benefits along with an increase in the green economy. In a country like India, proper waste management is not effectively possible due to lack of awareness and illiteracy. Holistic waste management can be carried out by involving the waste collectors and recyclers, extended producer responsibility, stack holders, targeted education, and awareness camps. The chapter “Solid Waste Management Methods: A Technological Analysis of Mechanical, Chemical, Thermal and Hybrid Means” authored by Dr. Neelancherry Remya details about the different methods to be adopted for the treatment depending on the characteristics of the waste. According to this study, cost-effectiveness and end-use of the byproduct should be considered while opting for the treatment technology on a larger scale. The chapter “Characterization and Sustainable Utilization of Steel Slag (SS) as a Recycled Aggregates in Indian Concrete Industry” authored by Dr. Vidyadhar V. Gedam studied the utilization potential of steel slag obtained from Indian steel industries. Steel slag is obtained as a byproduct from the steel industries, and from the research, it is found that it has high potential to be used and can be replaced by the natural aggregates. Thus, the utilization of steel slag will not only be helpful in the v

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utilization of the industrial waste but also plays an important role in the conservation of the environment by limiting the use of natural aggregates. The chapter “Application of Green Synthesis of Nanoparticles for Removal of Heavy Metal Ion from Industrial Waste Water” authored by Dr. Sudesh Kumar focuses on the use of nanoparticles for the removal of heavy metals from the wastewater. The use of conventional methods poses environmental pollution along with expensive chemicals. The results have revealed that the phytoremediation method generates a small amount of biomass as a byproduct which can be used as a fertilizer thus limiting the environmental pollution. The chapter “Waste Management in Indian Pharmaceutical Industries” authored by Dr. Alok Sinha emphasizes the different treatment technologies used for Pharmaceutical wastes. Research on Membrane separation Technology has been carried out and 90% removal efficiency in COD has been achieved. But due to high toxicity, the physico-chemical method must be preceded by biological methods. The chapter “Erosion Management of Riparian Ecosystem in Coal Mining Area Through Selective Vegetation” authored by Dr. Nishant K. Srivastava investigates the eco-restoration of mine soil through the plantation of efficient photosynthetic and soil conserver species. The soil and water conservation potential and physiological behavior of the planted species have also been assessed. Planting the native species helps in improving the physico-chemical characteristics of the mine soil. The chapter “Urban Solid Waste Management for Enhancement of Agricultural Productivity in India” authored by Rajiv Ganguly focuses on the utilization of the large voluminous quantities of Municipal Solid Waste generated to be reused effectively for agricultural purposes. It also discusses the engineering indexes of compost generated from MSW (Fertility Index and Clean Index) as an usability indicator as different composting techniques lead to the generation of different qualities of compost. The chapter “Food Waste Utilization for the Production of Biogas by Anaerobic Digestion: A Case Study in Coal Capital of India” authored by Dr. Raj Shekhar Singh creates awareness about the Food Waste Utilization for the production of Biogas and approaches leading to Methane Generation through anaerobic digestion of food waste and sustainable renewable energy. The present study was to create an Organic Processing Facility to generate biogas by a economically and eco-friendly method. Food wastes nutrient content analysis exhibited optimum and balanced nutrients for anaerobic microorganisms. The chapter “Development of Low-Cost Microbial Fuel Cell for Converting Waste to Electricity and Abating Pollution” authored by Dr. Makarand M. Ghangrekar presents the introduction of novel materials which can contribute to reducing the fabrication cost of MFC for field application and assist in maximizing the power output. Anode materials can be used as they encourage biofilm formation, substrate metabolism, and extracellular electron transfer and are also inexpensive. Moreover, these materials possess good electrical conductivity with low resistivity and a large specific surface area for bacterial attachment. Even the ceramic membranes, in comparison to the polymeric membranes, possess superior physical integrity, thermal

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stability, and chemical resistance, which make them appropriate to deal with wastewater having different pH ranges. The performance of MFC is dependent on a relationship between its biotic and the abiotic components and also found that transition metals are most suitable for the development of microbial fuel cell. The chapter “Recent Developments in Energy Recovery from Sewage Treatment Plant Sludge via Anaerobic Digestion” authored by Raja Sonal Anand attempted to extensively review the principles of Anaerobic Digestion of sewage sludge, the process parameters and their interaction, the design methods, various pre-treatment techniques, and the recent developments to reduce the impact of the difficulties in each technique. After the review, it was concluded that optimization of different parameters for anaerobic digestion should be done to increase the efficiency. The Government should also frame policies and regulations to promote biogas usage and maintain proper statistical data. The chapter “Management of Waste Plastic: Conversion and Its Degradation as an Environment Concern in Asian Country” authored by Dr. Sudesh Kumar deals with the use of plastic and its degradation at the National and International level. The occurrence of plastics in the environment, whether as macro-plastic wreckage or as micro-plastics, has extensively been recognized as a universal problem. It embodies one of the utmost stimulating anthropogenic phenomenons which disturb the globe. It has emphasized on restricting landfill for non-biodegradable and non-recyclable plastics. Also, region- and problem-based strategies should be made. The chapter “Gold Phytomining in India: An Approach to Circular Economy in the 21st Century” authored by Dr. Sahendra Singh emphasized on the issue of phytomining of Gold in India. The Gold import bill of India is 40 billion dollars while its production is less than 2 tons per year. Hence, by practising the Gold phytomining will not only improve the economic condition but will also help to generate employment. It suggests the need of establishing a Research and Development Center to work on the feasibility of gold phytomining and its impact on the overall socio-economic growth of the mining areas. The last part of the book entitled Update, Conclusions and Recommendations for “Environment Management: Waste to Wealth in India” closes the book with the main conclusions and recommendations of the volume, as well as an update of some important recent publications of interest to the book to support the audiences with recent information that were not covered by the authors. Special thanks to all who contributed to making this high-quality volume a real source of knowledge and the latest findings in the Waste to Wealth in India. We want to thank the authors for their invaluable contributions. They did a lot of efforts during all phases of the book production starting from writing, revising based on the reviewers’ comments and Springer evaluation reports, and finally checking the proofreading of the chapters. It would not have been possible to produce this high-quality book and make it a reality without the efforts of the authors. Much appreciation and great thanks are also owed to Andrey Kostianoy, the Editor of Springer Water Series for his constructive comments, advice, and critical reviews. Acknowledgements are extended to include all members of the Springer team who have worked long and hard to produce this volume.

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The volume editor would be happy to receive any comments to further improve future editions. Comments, feedback, and suggestions for further improvement, or proposals for new chapters for the next editions are welcome and should be sent directly to the volume editors. Bhopal, India Zagazig, Egypt Bhopal, India March 2020

Shalini Yadav Abdelazim M. Negm Ram Narayan Yadava

Contents

Introduction Waste Management and the Agenda 2030 in the Indian Context . . . . . . . Ram Boojh

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Waste to Wealth Solid Waste Management Methods: A Technological Analysis of Mechanical, Chemical, Thermal and Hybrid Means . . . . . . . . . . . . . . . . Neha Shukla and Neelancherry Remya

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Characterization and Sustainable Utilization of Steel Slag (SS) as a Recycled Aggregates in Indian Concrete Industry . . . . . . . . . . . . . . . . Vidyadhar V. Gedam, Pawan Labhasetwar, and Christian J. Engelsen

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Application of Green Synthesis of Nanoparticles for Removal of Heavy Metal Ion from Industrial Waste Water . . . . . . . . . . . . . . . . . . . . . Supriya Singh, Pratibha, Vanshika Singh, and Sudesh Kumar

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Waste Management in Indian Pharmaceutical Industries . . . . . . . . . . . . . . Shivangi Upadhyay and Alok Sinha

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Erosion Management of Riparian Ecosystem in Coal Mining Area Through Selective Vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Nishant K. Srivastava and R. C. Tripathi Waste to Energy Urban Solid Waste Management for Enhancement of Agricultural Productivity in India . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 Rana Rishi and Ganguly Rajiv Food Waste Utilization for the Production of Biogas by Anaerobic Digestion: A Case Study in Coal Capital of India . . . . . . . . . . . . . . . . . . . . . 147 Raj Shekhar Singh, R. K. Singh, and N. Tripathi ix

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Development of Low-Cost Microbial Fuel Cell for Converting Waste to Electricity and Abating Pollution . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 Makarand M. Ghangrekar and Bikash R. Tiwari Recent Developments in Energy Recovery from Sewage Treatment Plant Sludge via Anaerobic Digestion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 Raja Sonal Anand and Pramod Kumar Waste and Sustainability Management of Waste Plastic: Conversion and Its Degradation as an Environment Concern in Asian Country . . . . . . . . . . . . . . . . . . . . . . . . 235 Pratibha, Sudesh Kumar, Supriya Singh, and Vanshika Singh Gold Phytomining in India: An Approach to Circular Economy in the 21st Century . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249 Sahendra Singh Conclusions Update, Conclusions and Recommendations for “Environment Management: Waste to Wealth in India” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261 Abdelazim M. Negm, El-Sayed E. Omran, Shalini Yadav, and Ram Narayan Yadava

Introduction

Waste Management and the Agenda 2030 in the Indian Context Ram Boojh

Abstract With the concept of sustainability gaining ground, conventional waste management approaches which considered waste as a necessary evil of the development process, are fast changing. Waste is now considered as an important resource and critical component of the circular economy. Implementation of an efficient and sustainable waste management system in our cities and towns is vital for sustainable development and fulfilling of the commitments made under Agenda 2030 and Sustainable Development Goals (SDGs). Although there is no specific Goal for waste in SDGs, it is well embedded either explicitly or implicitly in almost 13 of the 17 Goals. India is facing a major waste management challenge. Apart from organized waste management through the urban local bodies, informal unorganized waste management sector provides employment opportunities to around a million people in the country. Use of municipal waste to produce energy is being practiced by some local municipalities. However, many of waste to energy plants in India have been unsuccessful due to low calorific value of the waste and its non-segregation at the source. The waste generated from healthcare facilities in India is also of serious concern to community health and environment due to improper management practices and poor or non-compliance of rules. India is also implementing the extended producer responsibility (EPR) policy which sets the responsibility of the producer of a product beyond conventional sales to its post-consumer or end-of-life (EOL) stage thus leading to a circular economy. Nature Based Solutions (NBS) are also gaining momentum for environmentally sustainable, economically beneficial and socially inclusive system for waste management. Waste management is linked to many of the sustainability issues related to urban areas. It is an entry point for addressing related issues of health, sanitation, and overall environmental improvement including the achievement of SDGs. Co-benefits of sustainable waste management for climate change, health, water and sanitation, as well as responsible production and consumption need to be promoted for realizing the potential of wastes in the achievement of SDGs. R. Boojh (B) CEO, Mobius Foundation, Delhi 110092, India Former Programme Specialist, Ecological Sciences, UNESCO South Asia Cluster Office, New Delhi, India © Springer Nature Switzerland AG 2022 S. Yadav et al. (eds.), Environmental Management in India: Waste to Wealth, https://doi.org/10.1007/978-3-030-93897-0_1

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Keywords Waste management · Sustainable development · Agenda 2030 · Circular economy · Biomedical waste · Extended producer responsibility · Nature based solutions

1 Introduction Modern society is considered to be the most wasteful one because of its contribution to huge amounts of trash in every part of our biosphere. Rising population, rapid urbanization, unsustainable production and consumption patterns, growing consumerism, and rising standards of living are leading to increased waste all around us. According to the World Bank [1], waste generation in world’s urban areas was around 2.01 billion tonnes, in 2016 which is expected to go up by 70% reaching to 3.40 billion tonnes by 2050. While, developed countries having 6% of world’s population generate about 34% of the global waste, emerging economies of China and India, are also becoming the major waste generators [1, 2]. The global average per capita waste generation is 0.74 kg with a range from 0.11 to 4.54 kg [1]. About 1/3rd of the waste generated worldwide are not managed properly in an environmentally safe manner [1]. Apart from the quantity of waste generated, its quality- the nature and composition, also varies according to lifestyle, income levels, and population density. While, poor and marginalized communities particularly in developing and low-income countries produce waste lesser in quantity and diversity (quality) than the developed nations, they are the one who bear the brunt of health and sanitation consequences of the waste mismanagement. Implementation of sustainable and effective waste management systems in local urban bodies is expensive often costing 20–50% of their total budget [1]. Over 90% of waste generated in majority of low income countries is often dumped openly or burned due to poor management practices and lack of resources for proper disposal and treatment. Unsustainable waste management practices cause serious health, safety, and environmental problems, polluting water resources including rivers and oceans, clogging the drains, flooding, and creating breeding grounds for disease vectors [3–5]. Burning of waste also adds to air pollution which is a major health hazard. With the concept of sustainability gaining ground, the conventional approaches to waste management which considered waste as a necessary evil of the development process are fast changing [6]. Waste is now considered as wealth, an important resource and critical component of the circular economy. Nature has its own ingenious ways of managing the waste by assimilating, reducing, and recycling activities which occur as part of ecological processes. Traditional indigenous societies in many parts of the world live in harmony with nature, where there is no such a concept as waste. Nature Based Solutions (NBS) [7] for waste management are also gaining momentum currently as they are cost-effective, environment friendly and socially inclusive. Sustainable waste management practices have to emulate the zero-waste concept which include life cycle approach of waste minimization, reuse, and recycling.

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2 Sustainability Issues Related to Waste Management Waste is considered to be one of the major sustainability issues impacting all the three pillars of sustainable development, i.e., environment, society, and economy. Effective waste management is essential for achieving sustainability and improving the quality of life. Environmental impacts of badly managed waste such as inadequate collection and open dumping or burning are well known [5]. The practice of open dumping and burning of waste results in many environmental hazards including emission of toxic gases and particulate matter in the air causing serious respiratory and neurological disorders in humans and damaging vegetation and buildings. Open dumping also pollutes ground and surface water sources through toxic liquid runoffs and leachates. Organic waste discharged in water bodies depletes oxygen availability and deteriorates water quality for aquatic life [8]. Our oceans and seas are also getting increasingly polluted as a result of unsustainable waste management practices on land, by sea vessels, and runoff from sewage and polluted streams. The world focused its attention on waste, especially plastic waste during the world environment day 2018 which had the theme ‘beat plastic pollution’. The year saw global efforts to create awareness about the issues related to plastic pollution particularly in our rivers, lakes, and oceans, causing harm to ecological processes and aquatic fauna and flora [3]. Wastes contribute around 3% of the global greenhouse gas (GHG) emissions responsible for climate change and global warming, primarily from methane emissions from landfills and open burning at dumpsites [4]. According to the International Solid Waste Association (ISWA) estimate, improved waste management can contribute to GHG reduction to the tune of 15–20% [4]. Besides, impacting the environmental sustainability, waste also has its social and economic impacts on the society particularly in the urban centres. Sustainable waste management leads to social and economic wellbeing while improving the environmental parameters. The social and economic costs of poor waste management put an enormous burden of disease on society. According to the World Bank estimates, integrated waste management costs for basic systems meeting good international hygienic standards, is to the tune of US$50–US$100/tonne [1].

3 Agenda 2030, SDGs and Waste Sustainability issues and sustainable development have currently become the most important global agenda being part of almost all the global discourses related to humanity’s survival on the planet earth [9, 10]. The Agenda 2030 (Transforming our world: the 2030 Agenda for Sustainable Development), adopted unanimously by the United Nations General Assembly in September 2015, is a path-breaking and transformative vision for creating a sustainable world by 2030 [11–13]. The key element of the Agenda 2030 is based on five principles (Ps), i.e., people, planet, prosperity, peace and partnership. The Agenda provides a blueprint and action plan

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for almost all the possible problems of the planet including poverty alleviation, health promotion, climate action, ecological restoration and socioeconomic inclusion so as to leave no one behind. The Agenda 2030 is universal, representing the commitment of all the countries “to create conditions for sustainable, inclusive, and sustained economic growth shared prosperity, and decent work for all [13]”. The Agenda sets 17 Sustainable Development Goals (SDGs) and associated 169 targets, most of which is to be achieved by 2030. SDGs are built on the foundation of the Millennium Development Goals (MDGs)—eight anti-poverty targets that global community committed to achieve by 2015 [14]. The MDGs, adopted in 2000, was a unifying agenda with specific goals and targets for alleviating poverty, ending hunger, disease and gender inequality, providing access to water and sanitation and ensuring environmental sustainability. The SDGs, while including goals for the achievement of unfinished business of the MDGs, provide a way forward to broaden the scope of sustainability to address almost all the pressing problems of humanity including the root causes of poverty and universal need for development that supports a safe and sustainable planet. SDGs do not contain a separate waste related Goal as such, however, waste management is embedded either explicitly or implicitly in almost 13 of the 17 Goals (Table 1). This can be well understood from the fact that improving sustainable waste management practices, can significantly contribute to the achievement of many of the SDG targets. In essence, effective waste management is the key driver of sustainability, thereby sound waste management is one of the key elements for the achievements of many of the goals and targets [15, 16]. Efficient waste management, therefore, not only contributes positively to the achievement of SDGs but also leads to secure environmental, economic and health benefits leading to sustainability through resource recovery and circular economy. However, if waste management issues are not addressed properly, it can pose serious risk to the environment and human health and overall sustainability of people and the planet (Fig. 1). From the above, it is clear that waste management is reflected explicitly in goals addressing health, water, cities and human settlements, and responsible consumption and production. However wastes find indirect connection to the goals on poverty, agriculture, oceans, decent work, and climate change. It is less pronounced in areas such as education and gender equality. Implementation of an efficient waste management system in our cities and towns is vital for sustainable development and fulfilling the commitments of the Agenda 2030 and SDGs (Fig. 2). From an analysis of SDGs in terms of waste management, it is clear that the goal of sustainable waste management should lead from linear to circular economy based on principles of 3 Rs- reduce, reuse and recycle. There are various approaches to consider waste and the circular economy’s role in the 2030 Agenda, especially in the SDGs for sustainable cities and communities (SDG 11), for responsible consumption and production (SDG 12) and life below water (SDG 14). E-waste management is another important area which contributes to the achievement of SDGs, specifically 11.6 and 12.5. NBS (Nature Based Solutions) for waste can be linked to the Goal 14 and 15.

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Fig. 1 How waste management can help achieve Global Goals? Adapted from Lenkiewicz [16]

4 Electronic Waste Electronic waste or e-waste is an important area of concern for environment and sustainable development. Rapid advances in electronics, information technologies and digital economy, have transformed our everyday life and lifestyle. These have also resulted in generation of huge amount of e-wastes with adverse impacts on environment and public health. Improper and haphazard disposal of e-wastes from discarded electronic devices such as computers, printers, copiers, cellphones, television sets, audio–video materials, and batteries, often result in leaching of hazardous

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Fig. 2 Circular economy benefits are manifold including environmental, economic and social [29]

toxic substances into soil and groundwater. Many of these products can be reused, refurbished, or recycled in an environmentally sound manner so that they are less harmful to the environment and public health. E-waste is one of the fastest growing solid waste sector having grown up from 20 million tonnes globally per year in 2000 to 53.6 million tonnes in 2019 [17–19]. This amounts to an average global e-waste generation of 7.3 kg per person, varying from 28.5 kg in Norway to around 2 kg per person in African countries. India is the third largest generator of e-waste with about 3.2 Mt of e-waste (2.4 kg per person) while China with 10.1 Mt tops the list followed by the USA (6.9 Mt) [19–21]. Sustainable management of e-waste owing to its complex nature, is quite challenging not only for developing economies but also for industrialized developed nations who despite their well-established waste management systems are struggling with the problem. There are variety of E-waste management options available including recovery of precious metals like Iron, copper, and gold for use as secondary materials. Value of such materials in the global e-waste markets in 2019 was estimated to be equal to approximately $57 billion USD [20]. As per some estimates, only about 20% of e-waste is recycled through appropriate channels, rest is just discarded as trash [20]. Scientific treatment and recycling of e-waste can create decent jobs in the refurbishment and recycling sector, thus contributing to SDG 8. This can be done in an organized manner by involving all concerned stakeholders, including end users, policy makers, industries, and businesses [17]. For an Effective, efficient and scientific e-waste management, there is need to consider life cycle approach which can contribute towards the achievement of several goals of the Agenda 2030 in particular, the SDGs related to environmental protection (Goals 6, 11, 12, and 14), health (Goal 3) and employment (Goal 8). Sound management of e-waste can create new areas of economic growth, employment and entrepreneurship, thus contributing to the overall sustainability imperatives of Agenda 2030 [17, 18].

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5 Circular Economy for Sustainable Development The concept of circular economy (CE) has its origin in ecological economics, environmental economics, and industrial ecology which was proposed mainly to offset the negative impacts of industrial wastes on the environment [21–23]. It is a new paradigm for development gaining momentum for sustainable waste management and being promoted in place of the traditional linear economy based on ‘take, make and dispose’ model of production. CE is defined as “an economic system which replaces the ‘end-of-life’ concept with reduce, reuse and recycle of materials in production/distribution and consumption processes, with the aim to accomplish sustainable development [23, 24].” Transition to a circularity from the linear economy is the way forward to achieve many of the Sustainable Development Goals (SDGs) such as no poverty (SDG1), responsible consumption and production (SDG12), sustainable cities and communities (SDG11), and the promotion of inclusive and sustainable industrialization and innovation (SDG9). The idea of circular economy is gaining momentum worldwide with countries putting in place several legal and administrative measures to bring in the elements of circularity in their economies [25–27]. Germany is the pioneer in the field being the first country to pass the Closed Substance Cycle Waste Management Act in 1994 to promote circular economy. Japan introduced its circular economy plan in the year 2000, by establishing a recycling based society. China has brought forward its circular economy initiative in the context of country’s waste and resource policy in 1998 formally endorsed by the central government in 2002 [25]. India has a long tradition of practicing circularity through many frugal and innovative ways of reuse, repair and recycle of materials. India’s informal waste recycling sector provides millions of jobs to the poorer section of society. The country has tremendous scope for application of circular economy model in many sectors [26]. According to the Ellen MacArthur Foundation Report (2016) [28], India could save costs amounting to 11% of its current GDP by 2030 and 30% of GDP by 2050 by adopting circular economy principles. The report further adds that circularity could bring reduction in greenhouse gas emissions to the tune of 23% by 2030 and up to 44% by 2050. The global economy is currently estimated to be only 9% circular [27]. If countries close this circularity gap through sustainable processes and technologies, the world’s resource productivity can grow up to 3% annually with 7% increase in the gross domestic product (GDP) as compared to current development estimates [27, 28]. This will bring in additional employment, reduced costs of waste management, pollution control and reduction in greenhouse gas emissions by more than half by 2050. CE has the potential to create economic and social benefits in terms of new job opportunities, increased welfare for low-income households and improvement in trade balances [29]. Transition towards circular economy will also require collaborative approach from markets, institutions and policy makers along with changes in behaviour of stakeholders involved in the product life-cycle [30].

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6 Sustainable Waste Management: Indian Scenario Waste management, in particular, the solid waste management in cities and towns of India is a major environment and sustainability issue owing to rapidly changing nature of urbanization and growing consumerism. These issues become more complex when considered in the context of SDGs and relevant policy and regulatory frameworks. As per the Central Pollution Control Board [31] estimates, India generated around 150,000 tonnes per day (TPD) of solid waste during 2014–2015, with daily per capita average of 0.11 kg. Approximately 80% of the total generated waste, was collected, while only 20% of this was processed or treated [32]. The composition of the generated waste is also of diverse nature with 40–45% organic, 20–30% inert component and the rest being plastics, paper, rags, and other components. The waste generation in India is likely to grow to more than double in quantity by 2025 reaching to 377,000 TPD as per the estimates of the World Bank [1]. Mumbai has the distinction of being the world’s fifth most wasteful city. Local municipal bodies are the main agencies responsible for collection, transportation and final disposal of waste. These bodies often lack adequate human and financial resources for effective and sustainable management of waste. Some of the municipalities have, however, evolved various innovative practices with support of the State and Central Governments to implement sustainable waste management systems. These are assisted by many non-governmental and civil society organizations particularly involved in door- todoor collection of segregated waste at the household level followed by decentralized composting in select localities. Local municipal bodies have made provisions for separate collection bins and necessary collection and transportation infrastructure in support of such initiatives. Public awareness activities carried out by municipalities and civil society organizations have also helped in promoting waste segregation at source. Government of India’s ambitious Swachh Bharat Abhiyan-SBA (Clean India campaign) launched nationwide by Indian Prime Minister in 2014 is being implemented as a national movement to realize the vision of a ‘Clean India’ [33]. The SBA has provided much needed push to the waste management in urban centres through improvement in the quality of urban infrastructure with assured services and efficient governance. SBA has also transformed the sanitation scenario particularly in rural India by achieving near total sanitation in a period of 5 years between 2014 and 2019 through setting the ambitious goal of eliminating open defaecation by the 150th birthday of Mahatma Gandhi (2nd October 2019). The campaign with its targeted interventions in 100 flagship districts through spirited social and mass media campaigns has helped in the achievement of desired outcomes. The programme is seen as a model case example and success story towards the attainment of the SDG 6.2 of universal access to safe sanitation [34]. Waste management is one of the important components of the five pillars of sustainable development as per the vision document of India’s planning think tank, the NITI Aayog [35] (Fig. 3). The document states that environmental sustainability in the country can be achieved through effective implementation of the Solid

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Fig. 3 Strategies for achieving a sustainable environment: waste management is one of the key component of the sustainable development strategy. Source NITI Aayog 2018, Strategy for New India@75 [35]

Waste Management Rules, 2016. This legislation has been further strengthened by expanding its scope to include management and handling of a variety of waste streams such as plastic waste, bio-medical waste, electronic waste, construction and demolition waste as well as trans-boundary movement of hazardous wastes. These regulations provide necessary tool in the hands of local authorities and regulatory bodies to achieve the national commitment towards UN SDGs. However, effective enforcement and implementation of these rules on the ground need to be ensured by the concerned authorities with support from all the stakeholders. The country faces many challenges related to the development and implementation of an effective waste management system which include policy and regulatory framework, technology choices, and the availability of appropriately trained human resources. Most of the urban local bodies face problems related to their inadequate capacities at the organizational and governance level including lack of financial resources. There is also lack of motivation and awareness and in certain cases non availability of support structures to facilitate environmentally sustainable practices in urban centres. Efficient and sustainable management of waste as a resource are being implemented in some residential societies in a few cities through organized collection, composting and recycling of household waste which employ about 1–2% of urban poor [6, 36]. Unfortunately, most of the waste recycling happens informally in the back yard of shanty colonies in an unorganized manner mostly through the waste recyclers also known as rag pickers, raddiwalas, kabadis or waste collectors. There is hardly any estimate of the amount of waste being recycled (estimate for Mumbai stands at 25%) through these unorganized efforts of thousands of waste recyclers. The informal waste management sector in India besides providing job opportunities for around a million people, offers many innovative and localized solutions to reduce, reuse and recycle the waste. Many new ventures such as Recykal, Raddi Express, Raddi Bazaar, and Raddiwala have come up with modern technological solutions for waste recycling sector linking generators, aggregators and recyclers across the value chain. The start-up venture namely, Karo Sambhav which means “make it possible” is working to clean up e-waste by involving multiple

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players—manufacturers, distributors, recyclers—to act sustainably and create a circular economy with the help of new digital solutions [20]. Waste to energy (WTE) is another important area being practiced by some urban local bodies [20, 36]. Conversion of waste into various forms of energy involves processes such as combustion, gasification, pyrolyzation, anaerobic digestion, and landfill gas (LFG) recovery [37]. The WTE plants help in converting the waste into renewable energy and organic manure, thus reducing GHG emissions by offsetting the need for energy from fossil sources and reducing methane generation from landfills [38, 39]. The process involves decomposition or biomethanation of biodegradable waste where organic matter is broken by microbes in the absence of oxygen and released biogas (methane) is used as cooking gas. The slurry produced as the bye product of the process is used as fertilizer. Small scale biomethanation plants to produce electricity from biogas have been installed in many Indian urban centres to run streetlights in the neighbourhood. However, many of such waste to energy plants in India have not been successful due to the low calorific value of the waste owing to its non- segregation into biodegradable and recyclable streams. Government of India has planned to establish a Waste to Energy Corporation of India to fast-track the waste to energy plants across 100 smart cities for generating around 500 megawatts of electricity. The proposal, however has been severely criticized by experts who question the viability of such WTE schemes. Further, many of the existing WTE plants have been closed due to difficulty in meeting air quality norms as a result of poor management and misguided assumptions about fuel streams [40, 41]. Sustainable waste management also finds its due place in India’s Nationally Determined Contribution (NDC) document submitted to UNFCC (United Nations Framework Convention on Climate Change) to fulfil the commitments of the Paris Climate Agreement [42]. NDC highlights the national policy framework for tackling environmental and sustainable development challenges with focus on clean and efficient energy, climate resilient urbanization, waste to wealth conversion etc. The NDC’s priority area on abatement of pollution also highlights some of its new policy initiatives related to circular economy such as fly ash utilisation, zero liquid discharge etc. [42]. The total greenhouse gas (GHG) emissions from waste contribute approximately 5% of overall GHGs [20]. Therefore, sustainable waste management can help in achieving the commitments of Paris Agreement on climate change along with the targets set under the SDGs.

6.1 Biomedical Waste Bio-medical wastes (BMW) generated by health care establishments, research facilities and laboratories, blood banks, forensic laboratories, veterinary institutions and animal houses pose serious challenge to public health and environment due to their hazardous and infectious nature [43]. As per estimates only about 15% of the total waste generated by health-care activities are considered hazardous which may be infectious, toxic, or radioactive. The problem of waste generated from health care

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facilities in India is of serious concern due to improper waste management practices and poor compliance of rules and regulations prescribed by authorities [43–46]. India’s Biomedical Waste (Management and Handling) Rules 1998 were notified as the first regulatory framework for effective management of biomedical waste (BMW) from healthcare facilities in the country [47]. These rules apply to all those involved in generation, collection, storage, transportation, treatment, disposal, or handling of bio medical waste from healthcare facilities, veterinary institutions, research establishments, forensic laboratories etc. Effective management of biomedical waste can contribute to the achievement of SDGs, particularly Goal 3 (Table 1). However, there is need for creating awareness about BMW management including its safe collection, disposal and treatment among healthcare personnel as well as general public [44, 47–49].

6.2 Extended Producer Responsibility (EPR) The EPR is a new concept being used for effective waste management by setting the responsibility across the waste value chain to minimize the environmental impact of the product throughout its life-cycle [50]. Such a responsibility extends beyond the conventional sales point to the post-consumer or end-of-life (EOL) stage. The idea is to encourage producers to design and produce long-lasting and easily recyclable products to reduce the cost of collection and recycling of waste and not to pass it on to the government or the environment. Electronic waste is one area where the EPR concept has been implemented in many countries as part of waste management policies. The concept of EPR was introduced for the first time in India through the waste management rules notified in 2016. The plastic waste management rules, 2016 mandates EPR provisions for all e-waste producers to set up reverse logistics for collection of e-waste and channelizing it to authorized recyclers [51]. The EPR policies are expected to be instrumental in ensuring implementation of 3R principle (Reduce-Reuse-Recycle) leading to a circular economy and sustainable waste management [50]. The EPR principle is based on sustainability principles to provide social economic and environmental benefits such as creating decent and sustainable employment options and saving millions to economy and environment thus contributing to the objectives of Agenda 2030 and SDGs. In many developing countries, recycling industry is mostly in the informal sector employing underprivileged groups of society and sometimes children. These units have efficient recycling system which can be further made sustainable by eliminating child labour and hazardous/polluting working practices [15]. Currently, over 90% of all e-waste in India is managed by the informal sector with no safety measures or scientific recycling techniques. EPR provisions are expected to bring accountability of this sector towards environment.

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Table 1 Waste management linkages to relevant goals and targets under SDGs (the main source of text in the table is adapted from http://sustainabledevelopment.un.org/post2015/transformingour world) [13] SDGs

Waste related Target relevant to waste

Rationale and linkage to sustainable waste management

Target 1.4: Ensure inclusive economic development through empowerment of poor Goal 1: Eliminate all kinds and and vulnerable communities forms of poverty everywhere in the world

Around 1% of the urban population globally is dependent on waste related occupations particularly on recycling for their living. Sound waste management can create decent jobs for poor and vulnerable people and communities engaged in this sector thus helping in ending the poverty

Target 2.1: Ensure access to safe and nutritious food to all Target 2.2: End all forms of Goal 2: End hunger and ensure malnutrition food and nutritional security through sustainable agriculture

Sound food waste management particularly donating leftover food from hotels, restaurants and community kitchens coupled with zero food wastage and treatment of food waste and residues will contribute to feed the hungry and needy and in reducing the carbon footprint

Target 3.9: Reduce deaths and illnesses from hazardous chemicals and air, water, and soil pollution and contamination

Sustainable waste management which involves stopping of open dumping and burning will contribute to better air quality and health by reducing air pollution. Improved biomedical waste management will contribute to reduction in communicable diseases, improved sanitation thus will result into better health and well-being

Goal 3: Ensure health and wellbeing for all

4.4: Empower youth and adults with appropriate skills including technical and Goal 4: Ensure quality vocational skills for decent, education and lifelong learning employment and opportunities for all entrepreneurship

Waste management sector can offer education, research and innovation opportunities to youth, entrepreneurs and researchers. Some innovative initiatives and start- ups related to green and circular economy, and 3 Rs reuse, reduce and recycling are emerging in this area (continued)

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Table 1 (continued) SDGs

Goal 5: Gender equality and empowerment of all women and girls

Goal 6: Access to clean water and sanitation for all

Goal 7: Sustainable, cost effective and reliable energy for all

Waste related Target relevant to waste

Rationale and linkage to sustainable waste management

Target 5.4: Women and girls are empowered to take their own decisions, their work is reasonably recognized and paid, appropriate provision of public services, infrastructure, and social protection policies are put in place

Women play an important role in reducing, reuse, recycling and segregation of waste. They are gainfully employed in many waste management and recycling related jobs

Target 6.2: Proper hygiene and sanitation facilities specially for women and girls of weaker sections are ensured Target 6.3: Water quality is improved by reducing pollution and eliminating wastes and hazardous chemicals and materials

Sustainable waste management can significantly improve sanitation and water quality. Poor water quality and waste water adds to the burden of diseases impacting health and well-being of women and girls disproportionally

Target 7.2: Renewable energy Waste can be used in making use is promoted and increased biogas and clean renewable energy for providing easy access to electricity in rural households. Waste to energy plants can provide solution to efficient solid waste management and renewable energy at the urban areas as well

Target 8.1: Inclusive and sustainable economic development through green Goal 8: Sustainable livelihood, jobs for all economic and employment opportunities for all

Waste management is an important area to provide employment and decent jobs, thus adding to green economic growth (continued)

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Table 1 (continued) SDGs

Goal 11: Sustainable, inclusive, safe and resilient urban human settlements

Goal 12: Responsible consumption and production

Goal 13: Urgent action to combat climate change and its impacts

Goal 14: Sustainable management and conservation of oceans, seas and marine resources

Waste related Target relevant to waste

Rationale and linkage to sustainable waste management

Target 11.6: Improved air quality and waste management for better environmental outcome in urban bodies

Sound waste management practices can significantly contribute to urban environmental improvement. Curbing waste dumping in open and water bodies and control of open burning of waste will reduce water and air pollution and contribute directly to better environment and public health

Target 12.3: Reduce food waste and losses at the retail and consumer levels Target 12.4: Environmentally sound management of chemicals and wastes throughout their life cycle Target 12.5: Reduce waste generation through prevention, reduction, recycling, and reuse

Modern consumption and production patterns generate a huge amount of waste. Zero food waste can lead to an improvement in waste management services

Target 13.2: Integrate climate change measures into national policies, strategies, and planning

Sound waste management practices can reduce greenhouse gas (GHG) emissions. Waste dumpsites contribute around 10% of manmade GHG emissions

Target 14.1. Reduce marine pollution of all kinds, in particular from land-based activities, including marine debris and nutrient pollution

Control of wastes/debris especially plastic pollution can significantly help in the conservation of marine environment

(continued)

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Table 1 (continued) SDGs

Goal 15: Sustainable management of forests, and biodiversity

Waste related Target relevant to waste

Rationale and linkage to sustainable waste management

Target 15.1: Conservation, restoration and sustainable use of terrestrial and inland freshwater ecosystems and their services, in particular forests, wetlands, mountains, and drylands

Sustainable waste management is important for healthy life on land. Plastic litter in forests are harmful to biodiversity and plant and animal life in general

7 Way Forward: Waste Management—Key to Achieving SDGs Scientific and environmentally sound waste management is one of the key elements of sustainable development. Several slogans and quotes acknowledge the fact that waste is wealth which can offer opportunities for its use in innovative ways to achieve environmental, economic, and social benefits for a sustainable future. A well designed and carefully implemented waste management policy will contribute to all three “pillars” of sustainable development (environmental, economic, and social). For a holistic and integrated sustainable waste management, it is essential to move towards a circular development model, where waste is treated as a resource and managed at the source itself by reducing its amount before its generation and later transportation and open dumping. These aspects have been highlighted in many global discourses including the New Urban Agenda (NUA) adopted at the United Nations Conference on Housing and Sustainable Urban Development (Habitat III) in Quito, Ecuador, on 20 October 2016 and endorsed by the UN General Assembly at its plenary meeting on 23 December 2016. The NUA calls for, “universal access to sustainable waste management systems to be guaranteed in urban settings. For this to be achieved, wide-ranging investments will need to be made in sustainable infrastructure and municipal decision-makers will need to be supported [52]”. The Quito Implementation Plan for the NUA further states that, “We commit ourselves to promote environmentally sound waste management and to substantially reducing waste generation by reducing, reusing and recycling waste, minimizing landfills and converting waste to energy when waste cannot be recycled or when this choice delivers the best environmental outcome. We further commit ourselves to reduce marine pollution through improved waste and wastewater management in coastal areas [52]”. These commitments have been made by all the countries as member states of the UN which were further consolidated and strengthened through Agenda 2030 and SDGs as elaborated in this paper. There is need for transformative action in the waste sector for its transition towards clean and green economy by prioritising waste minimisation and promoting the “4 Rs” (Reduce, Reuse, Recycle, and Recover). This will provide the

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way forward for sustainability of this sector, thus contributing to the achievement of the Agenda 2030 and climate goals.

8 Summary Sustainable waste management is linked to many of the sustainability issues related to urban areas. It is an entry point for addressing related issues of health, sanitation, and overall environmental improvement including the achievement of SDGs. Apart from local environmental benefits, waste management offers opportunities for sustainable livelihoods, entrepreneurship, decent jobs, climate amelioration and good governance by the adoption of new and innovative approaches and technologies including life cycle approach to waste. This will lead to a circular and green economy at large. There is a need to implement holistic waste management approaches considering the quantity and quality of waste in all its forms such as municipal solid waste, agricultural waste, sewage, industrial waste, hazardous waste, biomedical waste, and e-waste. Policymakers should come forward to support the transition from a linear to a circular economy through appropriate incentives and disincentives. The informal and unorganized recyclers need to be integrated into the system to increase the rate of recycling at the point of collection and decentralized recycling. The co-benefits of sound waste management for climate change, health, water and sanitation, and responsible production and consumption need to be promoted and strengthened for realizing the potential of waste in the achievement of SDGs.

9 Recommendations Following are some recommendations for effective waste management to support the SDGs and Agenda 2030: • Holistic waste management approach should be implemented considering the quantity and quality of waste in all its forms such as municipal solid waste, agricultural waste, sewage, industrial waste, hazardous waste, hospital waste and e-waste. This should involve adoption of new and innovative approaches and technologies including life cycle approach to waste leading to a circular and green economy. • Four Rs- reduce, recover, reuse and recycle, practices should be promoted involving all the sectors and stakeholders to have a zero waste, waste minimization, reuse and recycling system in place. • Waste should be treated as resource and managed accordingly by use of innovative and creative approaches generating useful products and employment opportunities, thus contributing to sustainable development.

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• Priority should be given to waste minimisation and promoting the segregation of waste at the source. Decentralized waste management particularly by organizing collection and transportation of segregated waste and recycling and composting at the local ward or Mohalla level, should be systematically planned and implemented. • Appropriate incentives and disincentives should be provided to support the transition from a linear to a circular economy to create economic and social benefits such as income generation opportunities, employment, tax reliefs, preference in social welfare schemes etc. • People engaged in informal and unorganized waste management practices should be integrated into overall urban waste management system to increase the rate of recycling at the point of collection and to promote decentralized recycling. • The co-benefits of sound waste management for climate change, health, water and sanitation, and responsible production and consumption need to be promoted and strengthened for realizing the potential of waste in the achievement of SDGs. • There is a need for minimizing e-waste generation, prevent illegal dumping and improper treatment of e-waste, promote recycling and create jobs in the refurbishment and recycling sectors. • The concept of Extended Producer Responsibility (EPR) should be implemented for all types of wastes, especially the e-waste on a priority basis. • Innovative and localized waste management solutions based on traditional best practices need to be promoted to minimize the waste burden of urban local bodies. • Effective biomedical waste management should be ensured through establishment of integrated common healthcare waste management facilities combined with secured landfill facility. Effective management of biomedical waste can contribute to the achievement of SDGs, particularly Goal 3. • Urban centres must innovate, explore and in some cases re-invent sustainable methods and technologies for the use of nature based solutions for waste management including use of ecosystem principles of recycling, vermicomposting etc. • Suitably designed communication strategy and waste reduction campaigns with incentives and rewards for citizens and waste workers in order to motivate the citizens in supporting local management policies and actions should be launched. • Education and outreach activities through schools and colleges, through media and locally available communication channels should be organized on a regular basis. • Community outreach programmes such as cleanliness campaigns and targeted awareness activities should be launched through residential committees/societies and NGOs.

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References 1. Kaza, S., Yao, C., Bhada-Tata, P., & Van Woerden, F. (2018). What a Waste 2.0: A Global Snapshot of Solid Waste Management to 2050. Urban Development, Washington, DC: World Bank. https://openknowledge.worldbank.org/handle/10986/30317License: CC BY 3.0 IGO 2. Chen, D. M., Bodirsky, B. L., Krueger, T., Mishra, A, & Popp, A. (2020). The world’s growing municipal solid waste: trends and impacts. Environmental Research Letters 15(7), 074021. https://iopscience.iop.org/article/https://doi.org/10.1088/1748-9326/ab8659 3. United Nations Environment. (2018). World Environment Day 2018. http://worldenvironmen tday.global/2018/ 4. UNEP and ISWA. (2015). Global Waste Management Outlook. United Nations Environment Programme (UNEP) & International Solid Waste Association (ISWA). International Environment Technology Centre: Osaka. http://www.unep.org/ietc/InformationResources/Events/Glo balWasteManagementOutlookGWMO/tabid/106373/Default.aspx 5. Ferronato, N., & Torretta, V. (2019). Waste mismanagement in developing countries: a review of global issues. International Journal of Environmental Research and Public Health 16(6), 1060. https://www.mdpi.com/1660-4601/16/6/1060/htm 6. Boojh, R. (1996). Promoting waste management. In P. K. Mathur & R. Boojh, & H. N. Verma (Eds.), Proceedings—national seminar on waste management (pp. 18–30). Lucknow University, Centre for Environment Education (CEE) & United Nations Children’s Fund (UNICEF). 7. IUCN Commission on Ecosystem Management. (2019). Nature-based Solutions. https://www. iucn.org/commissions/commission-ecosystem-management/our-work/nature-based-solutions 8. Kumar, M., & Prakash, V. (2020). A review on solid waste: its impact on air and water quality. Journal of Pollution Effects and Control 8, 252. https://www.longdom.org/open-access/a-rev iew-on-solid-waste-its-impact-on-air-and-water-quality.pdf 9. Boojh, R. (2003). Is a Sustainable World Possible? Connect, 28, 7–10. UNESCO Paris. 10. Boojh, R. (2013). Environmental sustainability for the world we want: moving from the MDGs to Post-2015. Lead article. Terre Policy Centre Newsletter, 1–3. 11. Boojh, R. (2017). Climate change and sustainable development. In N. Jerath, R. Saluja, P. Bassi, & K. H. Sidhu (Eds.), Climate Change and Sustainable Agriculture (pp. 3–15). Desh Bhagat University. 12. Boojh, R. (2017). b). Sustainable development goals: creating sustainable opportunities for all. International Journal of Scientific and Technological Development, 3, 3–6. 13. United Nations. (2015). Transforming Our World: The 2030 Agenda for Sustainable Development. https://sustainabledevelopment.un.org/content/documents/21252030%20Agenda% 20for%20Sustainable%20Development%20web.pdf 14. United Nations. (2015). We can end poverty: Millennium development goals and beyond 2015. https://www.un.org/millenniumgoals/ 15. Wilson, D. C. & Velis, C.A. (2015). Waste management – still a global challenge in the 21st century: An evidence-based call for action. Waste Management and Research, 33, 1049–1051. https://journals.sagepub.com/doi/pdf/10.1177/0734242X15616055 16. Lenkiewicz, Z. (2016). Waste and the sustainable development goals. https://wasteaid.org/ waste-sustainable-development-goals 17. WEF. (2019). A new circular vision for electronics: Time for a global reboot. World Economic Forum (WEF). http://www3.weforum.org/docs/WEF_A_New_Circular_Vision_ for_Electronics.pdf 18. Baldé, C. P., Forti V., Gray, V., Kuehr, R., & Stegmann, P. (2017). The Global E-waste Monitor— 2017, United Nations University (UNU), International Telecommunication Union (ITU) & International Solid Waste Association (ISWA), Bonn/Geneva/Vienna. https://collections.unu. edu/eserv/UNU:6341/Global-E-waste_Monitor_2017__electronic_single_pages_.pdf 19. Forti V., Baldé C. P., Kuehr R., & Bel G. (2020). The Global E-waste Monitor 2020: Quantities, flows and the circular economy potential. United Nations University (UNU)/United

Waste Management and the Agenda 2030 in the Indian Context

20.

21.

22. 23.

24.

25. 26. 27.

28.

29.

30.

31. 32.

33. 34.

35. 36.

21

Nations Institute for Training and Research (UNITAR)—co-hosted SCYCLE Programme, International Telecommunication Union (ITU) & International Solid Waste Association (ISWA), Bonn/Geneva/Rotterdam. 120 p. http://ewastemonitor.info/wp-content/uploads/2020/ 12/GEM_2020_def_dec_2020-1.pdf Parajuly K., Kuehr R., Awasthi A. K., Fitzpatrick C., Lepawsky J., Smith E., Widmer R., & Zeng X. (2019). Future E-waste Scenarios; StEP (Bonn), UNU ViE-SCYCLE (Bonn) & UNEP IETC (Osaka). 34 p. https://www.step-initiative.org/files/_documents/publications/FUTURE%20EWASTE%20SCENARIOS_UNU_190829_low_screen.pdf Ganesan, R. (2020). Cleaning up India’s mountains of e-waste: Grassroots start-up Karo Sambhav ramps up its quest for responsible recycling. https://news.microsoft.com/en-in/fea tures/karo-sambhav-responsible-e-waste-recycling-india/ Kirchherr, J., Reike, D., & Hekkert, M. (2017). Conceptualizing the circular economy: An analysis of 114 definitions. Resources, Conservation and Recycling, 127, 221–232. Ferronato, N.; Rada, E.C.; Gorritty Portillo, M.A.; Cioca, L.I.; Ragazzi, M.; Torretta, V. (2019). Introduction of the circular economy within developing regions: A comparative analysis of advantages and opportunities for waste valorization. J. Environ. Manag. 2019, 230, 366–378 Kirchherr, J., Piscicelli, L., Bour, R., Kostense-Smit, E., Muller, J., Huibrechtse-Truijens, A., & Hekkert, M. (2018). Barriers to the circular economy: evidence from the European Union (EU). Ecological Economics 150, 264–272 Yuan, Z., Bi, J., & Moriguichi, Y. (2006). The circular economy: a new development strategy in China. Journal of Industrial Ecology, 10(1–2), 4–8. Ellen MacArthur Foundation. (2016). Circular Economy in India: Rethinking growth for longterm prosperity. http://www.ellenmacarthurfoundation.org/publications/ de Wit, M., Hoogzaad. J., Ramkumar, S., Friedl, H., & Douma, A. (2018). The circularity gap report. Circle Economy. https://www.circle-economy.com/the-circularity-gap-report-ourworld-is-only-9-circular/#.WyPwctVL-po Ellen MacArthur Foundation, SUN and McKinsey Center for Business and Environment. (2015). Growth within: a circular economy vision for a competitive Europe. https://www.ell enmacarthurfoundation.org/assets/downloads/publications/EllenMacArthurFoundation_Gro wth-Within_July15.pdf Berg, A., Antikainen, R., Hartikainen, E., Kauppi, S., Kautto, P., Lazarevic, D., Piesik, S., & Saikku, L. (2018). Circular economy for sustainable development (p 24). Finland: Finnish Environment Institute Helsinki. https://helda.helsinki.fi/bitstream/handle/10138/251516/SYK Ere_26_2018.pdf?sequence=1&isAllowed=y Parajuly, K., Fitzpatrick, C., Muldoon, O., & Kuehr, R. (2020). Behavioral change for the circular economy: A review with focus on electronic waste management in the EU. Resources, Conservation and Recycling, 6, 2020, Article 100035 https://www.sciencedirect.com/science/ article/pii/S2590289X20300062 CPCB (Central Pollution Control Board). (2016). Municipal Solid Waste. http://cpcb.nic.in/dis playpdf.php?id=aHdtZC9TdHVkaWVzX29mX0NQQ0IucGRm Kumar S., Smith, S. R., Fowler, G., Velis, C., Kumar, S. J., Arya, S. R. & Kumar, R., Cheeseman, C. (2017). Challenges and opportunities associated with waste management in India. Royal Society Open Science. 4, 160764. https://smartnet.niua.org/sites/default/files/res ources/160764.full_.pdf PM India (2021). Swachh Bharat Abhiyan. https://www.pmindia.gov.in/en/major_initiatives/ swachh-bharat-abhiyan/ Curtis, V. (2019). Explaining the outcomes of the ‘Clean India’ campaign: Institutional behaviour and sanitation transformation in India. BMJ Global Health 2019;4, e001892 https:// gh.bmj.com/content/bmjgh/4/5/e001892.full.pdf NITI Aayog. (2018). Strategy for New India @75; 232 p, National Institution for Transformative Initiatives (NITI) Aayog, Government of India. Development Alternatives. (2014). Working paper: waste management and green economy. https://www.devalt.org/images/L2_ProjectPdfs/Working_Paper_Waste_Management.pdf

22

R. Boojh

37. Chakraborty, S., Majumdar, K., Pal, M. & Roy, P. K. (2019). Assessment of bio-gas from municipal solid waste for generation of electricity–A case study of Agartala city, International Journal of Applied Engineering Research, 14, 1265–1268. https://www.ripublication.com/ija er19/ijaerv14n6_07.pdf 38. US EPA. (2016). Municipal Solid Waste. US Environmental Protection Agency. http://www3. epa.gov/epawaste/nonhaz/municipal/ 39. Gautam M., & Agrawal M. (2021). Greenhouse gas emissions from municipal solid waste management: a review of global scenario. In S. S. Muthu (Eds.), Carbon footprint case studies. Environmental footprints and eco-design of products and processes. Singapore: Springer. https://doi.org/10.1007/978-981-15-9577-6_5 40. Ahluwalia I. J., & Patel U. (2018). Solid waste management in India: an assessment of resource recovery and environmental impact. In Working Paper no. 36; Indian council for research on international economic relations. https://think-asia.org/bitstream/handle/11540/8143/Wor king_Paper_356.pdf 41. Krishna, G. (2017). In India, critics assail proposal to build 100 waste-fuelled power plants Science. https://doi.org/10.1126/science.aan7043 https://www.sciencemag.org/news/2017/06/ india-critics-assail-proposal-build-100-waste-fueled-power-plants 42. Government of India. (2015). India’s Intended Nationally Determined Contribution: Working towards Climate Justice. http://www4.unfccc.int/submissions/INDC/Published%20D ocuments/India/1/INDIA%20INDC%20TO%20UNFCCC.pdf 43. World Health Organization. (2018). Healthcare Waste. https://www.who.int/news-room/factsheets/detail/health-care-waste 44. Kumar, S. R., Abinaya, N. V., Venkatesan, A., & Natrajan, M. (2019). Bio-medical waste disposal in India: From paper to practice, what has been effected. Indian Journal of Health Sciences and Biomedical Research, 12, 202–210. 45. Gupta, S., & Boojh, R. (2006). Report: Biomedical waste management practices at Balrampur Hospital, Lucknow India. Waste Management Research, 2006(24), 584. 46. Gupta, S., Boojh, R., Mishra, A., Verma, S. & Agarwal, N. (2008). Biomedical waste management practices at Chhatrapati Shahuji Maharaj medical University, Lucknow: A case study. Research in Environment and Life Sciences, 1(2), 77–80. 47. Gupta, S., Boojh, R., Mishra, A. & Chandra, H. (2009). Rules and management of biomedical waste at Vivekananda Polyclinic: A case study. Waste Management 29(2), 812–819 48. CPCB-Central Pollution Control Board. (2020). Bio-medical waste management rules, 2016. https://cpcb.nic.in/rules-3/updated on 29/05/2020. 49. Semwal, R. and Dharmedra. (2016). Environmental concern and threat investigation due to malpractices in biomedical waste management. International Journal of Advances in Science Engineering and Technology, 4, 1–6. 50. Shahas Zero Waste. (2017). Is the industry ready to implement extended producer responsibility policies in India? https://saahaszerowaste.wordpress.com/2017/08/17/is-the-industryready-to-implement-extended-producer-responsibility-policies-in-india/ 51. MOEFCC. (2020). Guideline document- uniform framework for extended producers responsibility (Under Plastic Waste Management Rules, 2016). http://moef.gov.in/wp-content/uploads/ 2020/06/Final-Uniform-Framework-on-EPR-June2020-for-comments.pdf 52. United Nations. (2017). New Urban Agenda. http://habitat3.org/wp-content/uploads/NUA-Eng lish.pdf

Waste to Wealth

Solid Waste Management Methods: A Technological Analysis of Mechanical, Chemical, Thermal and Hybrid Means Neha Shukla and Neelancherry Remya

Abstract Present chapter investigated mechanical thermal, chemical and hybrid treatment methods, their advantages, disadvantages and implementation for municipal solid waste management process. An overview of the existing solid waste treatment methods and their efficiency as per volume reduction and energy recovery in terms of syngas and bio-oil is provided. Considering the volume reduction of solid waste, incineration is found to be the best treatment method with 90% volume reduction. The highest syngas and bio-oil production was reported with gasification and pyrolysis process respectively. On the other hand, stabilization, application of acid/alkali substance, oxidation at low temperature with ozone and esterification found beneficial for ethanol production and neutralization of harmful substances present in solid waste. Hybrid technology such as fluffing, microwave pyrolysis and plasma found favourable as compared to conventional treatment methods due to high-energy recovery in a shorter span of time. Thus, the selection of the appropriate treatment method should be done on the basis of solid waste characteristics and desired end goal such as volume reduction and energy recovery. Keywords Solid waste · Conversion techniques · Waste to energy · Pyrolysis · Microwave · Plasma technology

1 Introduction Population growth, standardization and significant progress of industries resulted in magnificent growth in solid waste generation. Major cities of India like Ahmedabad, Hyderabad, Bangalore, Chennai, Kolkata, Delhi, and Mumbai generates about

N. Shukla · N. Remya (B) Department of Civil Engineering, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha, India e-mail: [email protected] N. Shukla e-mail: [email protected] © Springer Nature Switzerland AG 2022 S. Yadav et al. (eds.), Environmental Management in India: Waste to Wealth, https://doi.org/10.1007/978-3-030-93897-0_2

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2300, 4200, 3700, 4500, 3670, 5800 and 6500 tons per day of solid waste respectively [1]. This huge amount of generated solid waste varies in their properties and composition based on the locality of the waste generation, climatic conditions, standard of living of the people, etc. [2]. This enormous amount of irrecoverable and/or non-reusable fraction of the solid waste urges the requirement of different treatment technologies and practices for its effective management [3]. Management methods like shredding aim to reduce the volume of the generated solid waste and immobilization of toxic substances present in the solid waste are achieved by methods like stabilization. Waste to energy concept is gaining more attention recently due to the enormous energy harnessing potential for the major portion of the generated solid waste [4]. Several studies indicated effective, economic, and environmentally friendly conversion of energy from waste [5, 6]. This chapter presents a state-of-theart review of the technological aspects of mechanical, chemical, thermal, and hybrid conversion methods employed solid waste management. The review will provide an insight into the decision-making process while adopting a suitable solid waste management method based on the solid waste quantity, characteristics, economic aspects, end product reuse, etc.

2 Types of Solid Waste Conversion Technologies Different types of solid waste management methods are employed based on the initial characteristics of the solid waste, economic consideration, and the expected end use of the end products derived from the process. Keeping apart the biological conversion technologies, solid waste management methods with or without energy recovery includes mechanical, thermal, chemical, and hybrid technologies. The selection of different technologies primarily depends on the characteristic of the generated solid waste as well as its quantity and desirable by-products.

2.1 Mechanical Conversion Technology Mechanical conversion exploits mechanical means in order to change the physical character of solid waste. These processes generally alter the mechanical properties of solid waste such as size, shape, and surface area for better storage and disposal [7]. These processes include shredding, compaction, and solidification. Sometimes, the mechanical conversion also employed as a pretreatment technique before applying other techniques like chemical and thermal conversion techniques.

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27

Shredding

Shredding is performed primarily to achieve the size reduction of solid waste. The process breaks large solid waste into small pieces by tearing and breaking, to make material recovery and separation more effective. It reduces the average particle size of solid waste to a more workable size for better control in subsequent processing equipment. Hence, shredding primarily serves as a pretreatment option for subsequent energy recovery technologies [8, 9]. However, the implementation of shredding of solid waste for energy generation plants has not yet proven to be a broadly profitable investment for all solid waste management operations [10]. On the other hand, it produces different size distributions of solid waste, which enables automated material separation through air clarifiers, screens and optical sorters thus increasing the efficiency of solid waste disposal techniques [10]. Shredded solid waste is easy and cheaper to transport as compared to raw solid waste.

2.1.2

Compaction and Palletization

The compaction process is employed to achieve volume reduction of solid waste by mechanical compression. Due to its moderate capital, low operation, and maintenance cost, compaction is considered as an economical technique compared to other volume reduction methods [11]. Usually, compaction is adopted as a pre-treatment for landfilling. Compacted waste could effectively reduce land area requirement for disposal, leachate generation, and subsequent leachate treatment cost. However, as no treatment/compaction can only reduce the volume of solid waste, but it cannot reduce the potential hazard of solid waste. Further reconditioning of land containing compacted wastes can be extremely difficult, risky, and expensive [12]. On the other hand, mechanical compression and palletization of solid waste are employed to convert the waste to a densified homogeneous product, which can be used as fuel due to its enhanced physical properties such as ease of handling [13].

2.1.3

Solidification

Stabilization of hazardous waste and subsequent solidification into a monolith by incorporating appropriate binding material is successfully practised for hazardous waste materials [14]. In the solidification, binders such cement, fly ash, hydraulic lime, hydrated lime is used to bind the contaminants present in the solid waste, thus preventing the release of contaminants into the environment [15]. In general practice, end products of the biological and thermal treatments are subjected to stabilization and solidification prior to disposal or reuse [16]. Solidification enhances the compressive strength of the end product with a decrease in permeability and encapsulation of hazardous constituents of the solid waste [17]. Hodul et al. [15] reported that solidification results in an increase of 0.6 MPa of compressive strength in neutralization sludge obtained by an industrial process [15]. The solidified product

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can be used as dusting, base layer, and backfill material in embankment and road pavement based on its chemical characteristics [18]. However, studies reported a reduction in compressive strength by about 50% in 152 days [15]. This could be due to the chemical reaction between unreacted components presents within the solidified waste. Therefore, the solidified waste should be examined for its maximum strength and minimum leaching capability before using it for any other purpose.

2.2 Thermal Conversion Technologies In the thermal conversion of solid waste, the combustible portion of solid waste like paper, coal, agricultural residue, plastic, and biomass is converted to end product by application of thermal energy [19]. The process achieves volume reduction and conversion of waste to a harmless product along with energy recovery [20]. The energy produced by thermal conversion technologies can be used for different household and commercial purposes, thus, facilitating the reduced demand for fossil fuels. The state of art of thermal conversion technologies includes incineration, gasification, and pyrolysis.

2.2.1

Incineration

In the incineration process, the solid waste is burnt at a high temperature (more than 850 °C) in an oxygen-rich environment. This is the most commonly adopted technology for the treatment of mixed solid waste as well as hazardous waste [19]. The operating temperature of 1500 °C was reported for wastes such as Municipal solid waste (MSW), oils, solvents, and plastics. However, a slightly higher temperature, i.e., 1600 °C was adopted for the incineration of medical waste. About 70% of solid waste mass reduction and 90% of the volume reduction is achieved by the incineration process [21]. The series of steps involved in the incineration process is illustrated in Fig. 1. Final end products of this process include gases (carbon dioxide, nitrogen oxides, and sulphur dioxide) and ashes [18]. The end uses of generated gases include heating, steam production, and electric energy production. On the other hand, around 22% of the input (solid waste) is converted to bottom ash which constituted around 3% of the parent material [22]. Ash component is used in cement matrices for succeeding compaction [19] or landfilled after compaction [23]. Although, incineration causes the destruction and detoxification of carcinogens, contaminated and toxic organic present in the solid waste. On the other hand, dioxins and other toxic substances present in the residue of incinerated end product poses a great problem for the final disposal [18]. This necessitates the segregation of the harmful and toxic substance from the solid waste before the incineration process.

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Collection of solid waste

Optional shredding and sorting (depends on the nature and composition of solid waste)

Incineration of solid waste (Temp. > 850oC and excess of oxygen)

Residue (Ash) Landfilling

Gases (CO2, SO2, H2, NOX)

Utilize as heating, steam production and electric energy production

Fig. 1 Flow chart of the incineration process

2.2.2

Gasification

In the gasification process, carbonaceous materials of solid waste are converted to gaseous end product (syngas) at elevated temperature (700−1600 °C) and pressure (up to 33 bar) [18, 24]. The syngas from gasification is mainly composed of hydrogen (H2 ), methane (CH4 ), carbon dioxide (CO2 ), and carbon monoxide (CO). Various researchers reported CH4 and H2 generation ranging from 11.9% to 93.4% and 1.2 to 27% respectively, with different solid waste under optimized conditions (Table 1). The syngas can be used to produce electric power, or as a replacement for natural gas and transportation fuels [25]. As per electricity generation is concerned, the gasification process can generate approximately 1000 kWh of energy from 1 ton of Table 1 Gas generation by gasification of different solid waste [29–31] Type of solid waste

Optimized conditions

Outcomes

Feed rate (Kg/hr)

Operating temperature (°C)

Holding time (Min)

Palm kernel shella

1

850

20 Min

8.0 10.80

Methane (%)

Hydrogen (%) 80.0

Rice husk

0.78

850

30 Min

Bagasse

2074.68

871

NA

7.89

16.84

Nutshell mix

56,833.33

871

NA

8.61

22.87

Switchgrass

56,208.33

871

25 Min

8.62

20.83

a High

yield of hydrogen found due to catalytic cracking of hydrocarbons

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solid waste [26]. On the other hand, exploration of replacement of transportation fuel by H2 is intensively studied in recent years, and gasification possesses great potential for H2 gas recovery of solid waste (Table 1). As a whole, the process results in mass reduction by 70–80% and volume reduction by 80–90% of solid waste [26]. Solid residue (char) obtained from gasification can be converted to valuable products like chemicals, fertilizer, and sanding material for road service. Gasification of various carbonaceous wastes such as wood waste, agricultural waste, food waste, and MSW has been explored in the past [27]. However, contamination of syngas by undesired products such as particulate, alkali metals, tar, chloride, and sulfide the problem associated with it [28], which is to be addressed prior to the beneficial energy recovery process.

2.2.3

Pyrolysis

Pyrolysis of a carbon-based solid waste is considered as a thermal degradation process at high temperature (350–600 °C) in the absence of oxygen [19]. Pyrolysis can be performed for different household solid waste, trashes, garbage, wood chips, vegetable waste, different plastics like PVS, LDPE, HDPE PE, PS, etc. A detailed flowchart of solid waste pyrolysis with end products is described in Fig. 2. Pyrolysis syngas is primarily composed of H2 , CO, CO2 , CH4, and complex hydrocarbons obtained by the volatile substance at high temperature. Bio-oil produced from pyrolysis can be used as boiler fuel and as a blend with diesel. Pyrolysis process is primarily designed to enhance the syngas or bio-oil production. However, a small

Pyrolysis Reactor

Collection of solid waste

Preprocessing of solid waste (Drying, grinding etc.)

Landfilling or can be used as carbon source for other purposes

Solid Byproduct (Bio char)

(Absence of oxygen)

Gases

Condensable gases Liquid (Bio oil)

Can be used as a blend with diesel in engines

Fig. 2 Flow diagram of pyrolysis of solid waste

Non-condensable gases

Gases (composed of mainly CO, CH4 and H2)

Can be used in boilers and gas turbines

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Table 2 End products of different solid waste by pyrolysis process [32, 33] Type of solid waste Optimized conditions

End products

Feed rate (kg/h)

Operating temperature (°C)

Syngas (%)

Bio oil (%)

Char (%)

Municipal mixed solid waste

0.02

900

25

32

43

Agricultural stalk

0.02

650

54

34

12

Rubbers, cornstalk and plastic

0.05

550 (holding time—5 min)

25

30

45

HDPE and wood chips

0.06

675 (holding time-0.018 min) (holding time—0.018 min)

50

20

30

Wood and plastic

0.01

600

20

60

20

quantity of char is also obtained as a end product of this process. Table 2 enlists the pyrolysis end products from different solid waste under optimized condition. The production of syngas varied from 20 to 54% with different types of waste under optimized conditions. Alternatively, the bio-oil fraction varied from 20 to 60%. From the results, it is evident that the type of feedstock and the operating parameters determines the efficiency of desired end product generation by the pyrolysis process. Pyrolysis has several advantages over other thermal conversion technologies such as reduced oxygen requirement for the waste conversion, char with high carbon content and un-oxidized metals and production of bio-oil with a high calorific value that improves its commercial value [18].

2.2.4

Comparison of Thermal Conversion Technologies

Table 3 enlists the highest reported volume reduction, mass reduction, ash generation, syngas production and bio-oil production by different thermal conversion technologies. The end products of different thermal conversion technique mainly dependent on the type and composition of solid waste and based on the selection of adopted conversion technique. Incineration process results in a maximum reduction Table 3 Conversion of solid waste by different thermal treatment technologies [34, 35] Thermal conversion techniques

Volume reduction (%)

Mass reduction Ash (%) generation (%)

Syngas production (%)

Biooil production (%)

Incineration

90

75

10

80

NA

Gasification

80

70

20

85

5

Pyrolysis

88

90

12

13

75

Components in syngas/ liquid stream (%)

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N. Shukla and N. Remya 70 60 Carbon monooxide

Carbondiaoxide

Hydrogen

50 40 30 20 10 0 Incineraon

Gasificaon

Pyrolysis

Fig. 3 Composition of syngas obtained by different thermal conversion techniques of solid waste [36–38]

in volume, whereas pyrolysis gives a maximum mass reduction of solid waste. On the other hand, as per the energy recovery, the gasification process is found best for the syngas production, and pyrolysis process found more suitable for bio-oil production. However, suitable thermal conversion technology is selected based on the type of solid waste and required end products. The syngas obtained by different thermal conversion technology showed variation in its composition (Fig. 3). From Fig. 3, it was observed that H2 was the primary and main constituents of syngas generated by pyrolysis and incineration, which constitutes 63 and 40% of the total syngas produced from the two processes respectively. However, the volume of syngas produced is much less in the pyrolysis process compared to that of incineration. On the other hand, H2 accounted for only 11% of the syngas produced by the gasification process that can be further increased by catalytic cracking of hydrocarbons. Up to 80% hydrogen yield in syngas (Table 2) was reported by catalytic gasification of palm kernel shell [29]. Therefore, gasification is the best suited thermal conversion technology as far as H2 generation is concerned. Alternatively, pyrolysis provided highest bio-oil yield under the optimized condition, which can be subsequently upgraded to transportation fuel.

2.3 Chemical Technologies The chemical process employs the application of chemicals for the conversion of solid waste into some other useful product or for disposal purposes. Chemical processes often involve pretreatments such as shredding, grinding, or mixing like mechanical process before the application of chemicals in order to enhance the exposure of

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the solid waste to a chemical agent. Stabilization, oxidation with ozone, esterification, application of acid/alkali substances are few examples of chemical conversion technology of the solid waste.

2.3.1

Stabilization

Stabilization is also termed as a modification technique of solid waste in which, physical and chemical characteristics of hazardous (toxic) wastes can convert into a non-toxic or less leachable product that can be easily handled, transported and stored [39]. Stabilization involves mixing of a binding agent such as cement, fly ash, hydraulic lime, hydrated lime into the contaminated media or solid waste [40]. Sometimes it may change the physical appearance of the stabilized end product. This technique protects human health and environment by immobilizing contaminants within the same media and mainly in practice for industrial solid waste [17]. Rodrfguez-Piñero et al. [41] during their study on treatment of Cr+6 present in dust obtained from the stainless steel manufacturing plant, reported a lack of standard evaluation procedure for the risk associated with heavy metal contamination [41]. Therefore, to evaluate the risk associated with heavy metal contamination, a leachability test of the product was taken into account. During the experiment fly ash, portland cement and hydrated lime were used as a binding agent. Sometimes chemical pretreatment of the solid waste was performed before stabilization, to reduce the hazardous effect of contaminants during the disposal. Sobiecka [42] performed stabilization of fly ash encapsulated in portland cement and found a reduction in leaching capability (about 70%) of fly ash. In addition, stabilization also increases the compressive strength of the stabilized solid waste end product [42]. Nawaz [39] stabilized hazardous sludge waste extruded from nickel electroplating plant [39]. This sludge contained a large quantity of sulfates, chloride of nickel, boric acid, and several other heavy metals. In the stabilization process, cement and brick kiln dust had been used as binder agents. In results, 80% increase was found in compressive strength of the stabilized end product with minimum leaching capability. However, this technique does not decrease contaminant toxicity of solid waste and thus cannot be used in sensitive areas [43]. In addition, this technique does not found suitable for waste material having volatile organic contaminants that can be removed by incineration or air stripping [44].

2.3.2

Low-Temperature Oxidation with Ozone

Low-temperature oxidation assisted by ozone (O3 ) has great potential to convert organic solid waste to carbon dioxide and water [45]. As having strong oxidizing potential, ozone enables the oxidation reactions at low temperature (100−25 °C), thus minimizing the external heat energy input [46]. Ozone can be generated by exposing oxygen (in the air) to corona discharge or UV light for the oxidation purpose of municipal solid waste at low temperature [46]. Ozone also can be used to treat

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leachate that has a negative impact on soil. Amr et al. [47] reported about 40% decrease in COD due to the oxidation of leachate in oxidation pond with ozone [47]. Its COD decreased by about 40%. Whereas, Nabity and Lee [46] experimented the oxidation of MSW using ozone and reported carbon dioxide and carbon monoxide as a gaseous end product with dried solid residue comprised with plastics, aluminium, cloth, and paper [46]. Presence of plastic clumps decreased the area exposer of the solid waste to ozone, thus resulting in the decreased conversion efficiency. Therefore, the process necessitates the segregation of plastic components from the solid waste to avoid the plastic melting at the operating temperature and subsequent clumping which results in a decrease in process efficiency [48].

2.3.3

Esterification

The esterification process involves the reaction of a triglyceride (fat/oil) with alcohol in the presence of an alkaline catalyst to convert the solid waste into some useful end products. In esterification, alcohol reacts with the fatty acids as a result monoalkyl ester or biodiesel formed with crude glycerol. This glycerol can be used in cosmetic, pharmaceutical, food and paint industries., The main output of the esterification is biodiesel. Despite the biodiesel production, high installation cost, low efficiency, and dependency on the type of solid waste are some of the major barriers for the use of this technique on a large scale. Quality of esterification resulted biodiesel can be improved by the addition of catalyst like sulfonated carbon, kraft lignin-based activated carbon (KLC) bearing SO3 H, COOH, and OH groups, acidic mesoporous carbonaceous materials (carbon acids derived from polysaccharide), etc. In view of catalytic esterification of solid waste, Guwahati [49] performed esterification of waste cooking oil with coconut coir and found 50% increase in free fatty acid conversion of waste cooking oil with coconut coir as compared to waste cooking oil alone [49]. Addition of carbon-400 SO3 H as a catalyst resulted in 100% esterification of rapeseed waste frying oil and sunflower with olive waste frying oil [50]. Therefore, the addition of catalyst found beneficial for the esterification process resulting in good quality of biodiesel.

2.3.4

Application of Acid/ Alkali Substances

Application of acid/alkali substance is performed to degrade the biomass into its basic components, primarily ethanol. Application of acid breaks down the lignin structure of solid waste and disrupt the crystalline structure of cellulose of organic solid biomass that favours in hydrolysis process of cellulose, in result, ethanol production gets accelerated [51]. Sulphurous, sulphuric, hydrochloric, hydrofluoric, phosphoric, nitric and formic acid are some of the examples of acid used in diluted or concentrated form for the conversion of solid waste [52]. This technique requires the separation of solid waste, application of high temperature, and a huge quantity of acid for the

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conversion of biomass in ethanol. However, corrosion of equipment at acidic condition, the formation of inhibitors such as furfural and hydroxymethylfurfural (HMF), degradation of the complex substrate resulting in loss of fermentable sugar and additional cost requirement for acid neutralization are some of the factors that reduce the process efficiency [9]. On the other hand, the addition of alkaline substance such as sodium hydroxide (NaOH), lime (Ca(OH)2 ) or ammonia (NH3 ) is used to delignify the solid waste [52]. Addition of alkali substance causes swelling of biomass, which leads to an increase in internal surface area, disruption of the lignin structure, and separation of structural linkages between lignin and carbohydrates. Thus, the degradation of lignin enhances the ethanol production that can be used as a useful renewable energy source. Thus, for the dewatering process of ligneous solid waste, the addition of alkali substances found effective as compared to the conventional waste dewatering process [53]. It was found that using dilute NaOH with straw resulted in 58% glucose conversion after alkali treatment. This glucose can easily be converted to ethanol [52]. Advantages of alkali substance addition for solid waste conversion includes simple devices, ease in operation, and high efficiency compared to acid addition process [54]. Acid treatment leads to a reduction in sugar production due to inhibitors, mentioned earlier, which is unfavourable for ethanol production. Several researchers [55–58] compared sugar production and lignin destruction from acid and alkali treatment and found that the alkali treatment best in the result. However, alkaline treatment found effective for ethanol production from biomass but after hydrolysis process of lignin in alkali treatment that also needed further enzymatic hydrolysis of intermediate product for better result. Ethanol production by using different chemical conversion techniques is listed in Table 4. The results indicated that esterification resulted in higher amount of ethanol (87%) in comparatively less time (8 h) as compared to other chemical treatment technologies. However, the selection of the particular treatment technology completely depends on the composition of biomass, desirable end products, and operating cost. Table 4 Ethanol production from the solid waste by different chemical treatment technologies [39, 46, 49, 59] Chemical Conversion technology

Requirement of pretreatment

Treatment time (days)

Ethanol production (%)

Stabilization

No

7–28

NA

Low-temperature oxidation with Ozone

Size reduction

0.3

NA

Esterification

Size reduction

0.3

87

Application of acid/alkali substances

Size reduction

1–2

58

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2.4 Hybrid Technologies Hybrid technology is considered as a combination of mechanical, thermal, and chemical conversion technologies of solid waste for better disposal and reuse purpose. The technology aims to achieve a strategical combination of various treatment methods to accomplish rapid and effective conversion with less operation cost and time. Commonly used hybrid technologies include fluffing, plasma, and microwave.

2.4.1

Fluffing

Fluffing includes a combination of mechanical and thermal conversion technology in which organic portion of solid waste is separated, sterilized, and processed to a pulp like material that is also known as fluff. In this process, first of all, mechanical conversion (shredding and metals separation) of the solid waste is performed, then the product is exposing to high-temperature steam in order to break its molecular bonds and to destroy pathogens. After that, grinding and dewatering process is subjected to thermally treated solid waste for the conversion of cellulosic material in to sanitized, sand-like granular fluff [60] This fluff can be used as a soil amendment because of its organic base and high nitrogen content. Fluffing results up to 30–75% reduction on volume [25]. In addition, due to its high nutrients contains, it can be easily used as a fertilizer for agricultural purpose. However, fluffs resulted from industrial effluent may also contain some organic compounds like acetone, methylene chloride, toluene, di(2-ethylhexyl)phthalate, di-nbutyl phthalate, and di-n-octyl phthalate that can pose little risk for soil and living organism, therefore before using it in any other purpose proper investigation of the fluff is necessary [61]. .

2.4.2

Plasma Technology

This conversion technology uses plasma state of matter that characterized as the fourth state of matter, for the conversion of solid waste [18]. In plasma, state atoms or molecule of a gas is partially or ionized with the help of plasma torch (made of copper or tungsten); this ionized gas helps in degradation of solid waste [62, 63]. Generally, 5000–8000 °F temperature range is used for this conversion process [64]. High-quality syngas (Carbon monoxide and hydrogen) is the main end product of this conversion technology with no generation of methane, hydrocarbons, or tars. The only small amount of inert glass-like material (slag) is obtained as a by product of this technique with minimal air pollutants that fall under environment regulations [65]. In an account of process efficiency, Unnisa and Hassanpour [66] stated that plasma technique gives better efficiency than conventional thermal conversion techniques [66]. Non-dependency on solid waste composition and moisture content are some of the major advantages of using plasma technology over other conversion

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techniques. Thus, this process eliminates the requirement of sorting and moisture control of solid waste; hence, make the solid waste conversion process more easy, feasible, and efficient [25]. In addition, this technology results in complete conversion of solid waste into synthesis gas, thus eliminating the requirement of byproduct landfilling. Complete and clear destruction of solid waste containing hazardous material, restriction on harmful emission of toxic waste, use of syngas as an electric source is some of the other benefits received by this process [67]. Moreover, it requires very less holding time (2 s) for the conversion of solid waste into its end products [65]. However, plasma technology required a relatively high level of maintenance and skilled labour for the process operation [18].

2.4.3

Microwave Technology

Microwave technology utilizes the microwave energy of electromagnetic spectrum derived from electrical energy for the conversion of solid waste. These microwaves resulted in the motion of molecule by rotation of dipolar element or/and by migration of ionic species present in solid waste. This motion of the molecules produce internal heat due to friction. Materials like charcoal, carbon black, and activated carbon are good microwave absorber and convert microwave energy into heat [68]. Microwave pyrolysis of solid waste is one of the advantageous technique of solid waste conversion that uses microwave energy for the pyrolysis of solid waste instead of supplying direct heat. In this process, mixed solid waste like biomass, coal, oil shale, glycerol, food waste, rice straw, wooden chips like other various lignocellulose material can convert to three useful end products (bio-oil, syngas, and char). From previous studies based on microwave pyrolysis of different lignocellulose material, it was observed that end product yield of this conversion technique depends on the difference in sample weight, biomass characteristics, particle size, microwave power level, reaction temperature, reaction time, product vapor residence time, reactor design, and microwave heating manner [69–76]. Among these entire factor holding time and temperature of the reaction is the most critical factor. High temperature with long residence time gives a higher amount of syngas yield due to secondary cracking of hydrocarbons present in the vapours resulted by microwave heating. Whereas, low temperature with high residence time resulting in higher production of char, and higher temperature with less residence time resulted in an increased bio-oil yield. Depending upon the required end product of microwave pyrolysis, additives can be added. For example, to enhance bio-oil quality and quantity addition of hydrogen enrich plastic and catalyst like Al2 O3, activated carbon, Fe2 (SO4 ) 3, MgCl2 , H3 BO3 , and Na2 HPO4 can be used. However, char obtained as a solid residue of this conversion technique reposted as a good adsorbent and having a large surface area as compared to conventional pyrolysis. In addition, this conversion technique offers several advantages over conventional conversion process like providing non-contact heating, energy transfer instead of heat transfer, rapid heating of solid waste, high heating rate, volumetric heating, quick startup and stopping, higher safety and automation [77]. Instead of such advantages, the application of

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microwave technology is still limited to only lab scale systems because of its ineffectiveness and high-energy consumption at industrial scales. This technology is highly dependent on material properties and characteristics, operating parameters such as radiation time and other operational conditions [78] Moreover, further upgradation of microwave pyrolysis obtained bio-oil is required to promote its industrial favorability [79].

3 Conclusions The present study of solid waste treatment methods has revealed acceptability of different treatment methods for solid waste management depends on the end use and characteristics of solid waste. Keeping in view of the solid waste generation rate and reducing disposal space, mechanical methods can be considered for ease in transportation as well as pre-treatment method prior to other methods. Considering waste to energy concept and to meet the fossil fuel demand, gasification and pyrolysis are best merging technologies, which have a lower environmental impact than other methods. To stabilized/neutralize the harmful substances of solid waste, chemical technologies found best. However, the use of hybrid technologies over conventional ones not only making the management process more versatile in terms of sustainability but also can reduce the short and long term environmental and human health hazards. Therefore, proper implementation of the latest technologies in the sector of solid waste management can play a very important role in providing pollution free and sustainable environment.

4 Recommendations • Cost effective and end-use analysis of each solid waste treatment methods should be included for proper implantation of these technologies on a larger scale. • Integrated treatment technologies should be considered for the treatment of mixed solid waste. • Considering the versatile/heterogeneous composition of solid waste, selection of proper treatment technologies should be performed in such a manner that it can eliminate the segregation process of solid waste (such as plastics, food waste, tyres etc.).

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References 1. Kumar, S., Smith, S. R., Fowler, G., Velis, C., Kumar, S. J., Arya, S., Kumar, R. R., & Cheeseman, C. (2017). Challenges and opportunities associated with waste management in India. Royal Society Open Science, 4, 160764. https://doi.org/10.1098/rsos.160764. 2. Serge Kubanza, N., Simatele, M. D. (2019). Sustainable solid waste management in developing countries: a study of institutional strengthening for solid waste management in Johannesburg, South Africa. Journal of Environmental Planning and Management. doi:https://doi.org/10. 1080/09640568.2019.1576510. 3. Fernández-González, J. M., Grindlay, A. L., Serrano-Bernardo, F., Rodríguez-Rojas, M. I., & Zamorano, M. (2017). Economic and environmental review of Waste-to-Energy systems for municipal solid waste management in medium and small municipalities. Waste Management, 67, 360–374. https://doi.org/10.1016/j.wasman.2017.05.003 4. Lombardi, L., Carnevale, E., & Corti, A. (2015). A review of technologies and performances of thermal treatment systems for energy recovery from waste. Waste Management, 37, 26–44. https://doi.org/10.1016/j.wasman.2014.11.010 5. UNU, From Waste to Wealth: A workshop exploring environmentally, socially and financially sustainable wastewater management for rural and informal settlements (2013). 6. Length, F. (2014). Waste to wealth potentials of municipal solid waste : A case study of Ga-East municipal assembly. Ghana, 2, 113–121. 7. Vilar, O., & Carvalhod, M. (2004). Mechanical properties of municipal solid waste. Journal of Testing and Evaluation, 32, 11945. https://doi.org/10.1520/JTE11945 8. Emmanuel, J., Puccia, C., & Spurgin, R. (2001). Non-incineration medical waste treatment technologies. Health Care Without Harm Washington, 61. http://goo.gl/QrK3hB. 9. Ariunbaatar, J., Panico, A., Esposito, G., Pirozzi, F., & Lens, P. N. L. (2014). Pretreatment methods to enhance anaerobic digestion of organic solid waste. Applied Energy, 123, 143–156. https://doi.org/10.1016/j.apenergy.2014.02.035 10. Young, G. C. (2010). Municipal solid waste to energy conversion processes: Economic, technical, and renewable comparisons. doi:https://doi.org/10.1002/9780470608616. 11. Pulat, H. F., & Yukselen-Aksoy, Y. (2017). Factors affecting the shear strength behavior of municipal solid wastes. Waste Management, 69, 215–224. https://doi.org/10.1016/j.wasman. 2017.08.030 12. Cheremisinoff, n. p. (2003). Volume reduction technologies. In Handb. solid waste management waste minimization technology (pp. 130–173). http://www.sciencedirect.com/science/article/ B863N-4P61CB1-B/2/3914eebcd7a7e7c686e6528e0c51dde3. 13. Jamradloedluk, J., & Lertsatitthanakorn, C. (2015). Properties of densified-refuse derived fuel using glycerin as a binder. Procedia Engineering, 100, 505–510. https://doi.org/10.1016/j.pro eng.2015.01.397 14. US Environmental Protection Agency, Solidification/Stabilization Resource Guide, Environ. Prot. (1999) 86. EPA/542-B-99–002. 15. Hodul, J., Dohnálková, B., & Drochytka, R. (2015). Solidification of hazardous waste with the aim of material utilization of solidification products. Procedia Engineering, 108, 639–646. https://doi.org/10.1016/j.proeng.2015.06.193 16. Blaney, B. L. (1986). Treatment technologies for hazardous wastes: Part ii alternative techniques for managing solvent wastes. Journal of the Air Pollution Control Association., 36, 275–285. https://doi.org/10.1080/00022470.1986.10466070 17. Trussell, S., & Spence, R. D. (1994). A review of solidification/stabilization interferences. Waste Management, 14, 507–519. https://doi.org/10.1016/0956-053X(94)90134-1 18. Golomeova, S., Srebrenkoska, V., Krsteva, S., Spasova, S. (2013). Solid waste treatment technologies. Machines Technologies Materials, 9, 59–61. http://eprints.ugd.edu.mk/7733/1/ SOLID WASTE TREATMENT TECHNOLOGIES.pdf. 19. Castaldi, M. J. (2010). Environmentally benign energy technologies. In ACS Natl. Meet. B. Abstr. https://www.scopus.com/inward/record.uri?eid=2-s2.0-79951501980&partnerID=40& md5=e6c865ffb8d7ba3a778166e647670b55.

40

N. Shukla and N. Remya

20. Ryu, C. (2010). Potential of Municipal Solid Waste for Renewable Energy Production and Reduction of Greenhouse Gas Emissions in South Korea. Journal of the Air and Waste Management Association, 60, 176–183. https://doi.org/10.3155/1047-3289.60.2.176 21. Lam, C. H. K., Ip, A. W. M., Barford, J. P., & McKay, G. (2010). Use of incineration MSW ash: A review. Sustainability, 2, 1943–1968. https://doi.org/10.3390/su2071943 22. Ungureanu, G., Ignat, G., Vintu, C. R., Diaconu, C. D., & Sandu, I. G. (2017). Study of utilization of agricultural waste as environmental issue in Romania. Revista de Chimie, 68, 570–575. 23. Waste, I., & Handbook, T. (2002). Industrial Waste Treatment Handbook. https://doi.org/10. 1016/S0304-3894(01)00391-0 24. Morrin, S., Lettieri, P., Chapman, C., & Mazzei, L. (2012). Two stage fluid bed-plasma gasification process for solid waste valorisation: Technical review and preliminary thermodynamic modelling of sulphur emissions. Waste Management, 32, 676–684. https://doi.org/10.1016/j. wasman.2011.08.020 25. Pariatamby, A., & Tanaka, M. (2014). Municipal solid waste management in Asia and the Pacific Islands. http://www.worldcat.org/oclc/858862725. 26. Maya, D. M. Y., & Sarmiento, A. L. E. (2016). Cristina Aparecida Vilas Boas de Sales Oliveira, Electo Eduardo Silva Lora, RubenildoVieira Andrade, Gasification of Municipal Solid Waste for Power Generation in Brazil, a review of available technologies and their environmental benefits. Journal of Chemistry and Chemical Engineering, 10, 249–255. https://doi.org/10. 17265/1934-7375/2016.06.001 27. Sikarwar, V. S., Zhao, M., Fennell, P. S., Shah, N., & Anthony, E. J. (2017). Progress in biofuel production from gasification. Progress in Energy and Combustion Science, 61, 189–248. https:// doi.org/10.1016/j.pecs.2017.04.001 28. Dave, P. N., & Joshi, A. K. (2010). Plasma pyrolysis and gasification of plastics waste—A review. Journal of Scientific and Industrial Research (India), 69, 177–179. 29. Hussain, M., Tufa, L. D., Yusup, S., & Zabiri, H. (2018). A kinetic-based simulation model of palm kernel shell steam gasification in a circulating fluidized bed using Aspen Plus®: A case study. Biofuels. https://doi.org/10.1080/17597269.2018.1461510 30. Lau, F. S., Bowen, D. A., Hughes, E. E., Zabransky, R. (2002). Techno-Economic Analysis of Hydrogen Production by Gasification of Biomass, U.S. Dep. Energy (p. 154). https://doi.org/ 10.2172/816024. 31. Ghani, A. T. W. A. W. K., Moghadam, R. A., & Salleh, M. A. M. (2012). Gasification performance of rice husk in fluidized bed reactor: A hydrogen-rich production. International Journal of Energy and Environmental, 4, 7–11. 32. Jia, J. W., Lu, M. Y., Liu, L., Yang, F. S., Fu, X. M. H., Fu, X. M. H., Yang, D., Shu, X. Q. (2016). Copyrolysis energy analysis of municipal solid waste and agricultural stalk. Environmental Progress and Sustainable Energy, 35, 547–552. https://doi.org/10.1002/ep.12234 33. Jia, J., Liu, L., Yang, F., Fu, X., Yang, D., Hui, H., Fu, X., & Shu, X. (2018). Co-pyrolysis characteristics and product distributions of municipal solid waste and corn stalk. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 40, 510–515. https://doi.org/10.1080/ 15567036.2014.935892 34. Begum, S., Rasul, M. G., & Akbar, D. (2012). An investigation on thermo chemical conversions of solid waste for energy recovery 6, 624–630 35. Kolibaba, O., & Gabitov, R. (2017). Experimental study of thermal processing of solid waste 01028. https://www.matec-conferences.org/articles/matecconf/pdf/2017/24/matecconf_ hmt2017_01028.pdf. 36. Carabin, P., & Gagnon, J.- R. (2007). Plasma gasification and vitrification of ash-conversion of ash into glass-like products and syngas. World Coal Ash, 1–11. 37. Hlavsová, A., Corsaro, A., Raclavská, H., Juchelková, D., Škrobánková, H., & Frydrych, J. (2014). Syngas production from pyrolysis of nine composts obtained from nonhybrid and hybrid perennial grasses. The Scientific World Journal, 2014. https://doi.org/10.1155/2014/ 723092.

Solid Waste Management Methods …

41

38. Orlova, T., & Melnichuk, A. (2017). Modern technologies of processing municipal solid waste : Investing in the future Modern technologies of processing municipal solid waste : Investing in the future. 39. Nawaz, I. (2015). Stabilization/solidification of hazardous/toxic wastes using cement and brick kiln dust, 3, 22–26 40. Razzell, W. (1990). Chemical fixation, solidification of hazardous waste. Waste Management Ressource, 8, 105–111. https://doi.org/10.1016/0734-242X(90)90030-Q 41. Rodrfguez-Piñero, M., Pereira, C. F., de Elvira Francoy, C. R., & Vale Parapar, J. F. (1998). Stabilization of a chromium-containing solid waste: Immobilization of hexavalent chromium. Journal of the Air and Waste Management Association, 48, 1093–1099. https://doi.org/10.1080/ 10473289.1998.10463765. 42. Sobiecka, E. (2013). Investigating the chemical stabilization of hazardous waste material (fly ash) encapsulated in Portland cement. International Journal of Environmental Science and Technology, 10, 1219–1224. https://doi.org/10.1007/s13762-012-0172-1 43. Rahman, I. M. M., Begum, Z. A., & Sawai, H. (2015). Solidification/stabilization: A remedial option for metal-contaminated soils, In Environmental remediation technologies for metalcontaminated soils (pp. 125–146). https://doi.org/10.1007/978-4-431-55759-3_6. 44. Ioannidis, T. A., & Zouboulis, A. I. (2005). Hazardous industrial waste stabilization using inorganic phosphates: Investigation of possible mechanisms. Pure and Applied Chemistry, 77. https://doi.org/10.1351/pac200577101737. 45. Nabity, J. A., Andersen, E. W., Engel, J. R., Wickham, D. T., & Fisher, J. W. (2008). Development and design of a low temperature solid waste oxidation and water recovery system. SAE Technical Paper. https://doi.org/10.4271/2008-01-2052 46. Nabity, J. A., & Lee, J. M. (2015). Low temperature ozone oxidation of solid waste surrogates. Advances in Space Research, 56, 970–981. https://doi.org/10.1016/j.asr.2015.05.026 47. Amr, S. S. A., Aziz, H. A., Adlan, M. N., & Aziz, S. Q. (2013). Effect of ozone and ozone/fenton in the advanced oxidation process on biodegradable characteristics of semi-aerobic stabilized leachate. Clean–Soil, Air, Water, 41, 148–152. https://doi.org/10.1002/clen.201200005 48. Jovovic, A., Vujic, G., Pavlovic, M., Radic, D., Jevtic, D., & Stanojevic, M. (2011). Spontaneous ignition/low temperature oxidation of municipal solid waste. Revista de Chimie, 62, 108–112. 49. Guwahati, T. (2017). Study of esterification of waste cooking oil using solid acid catalyst derived from coconut coir study of esterification of waste cooking oil using solid acid catalyst derived from coconut coir. 50. Luque, R., & Clark, J. H. (2011). Biodiesel-Like biofuels from simultaneous transesterification/esterification of waste oils with a biomass-derived solid acid catalyst. ChemCatChem, 3, 594–597. https://doi.org/10.1002/cctc.201000280 51. Lenihan, P., Orozco, A., O’Neill, E., Ahmad, M. N. M., Rooney, D. W., & Walker, G. M. (2010). Dilute acid hydrolysis of lignocellulosic biomass. Chemical Engineering Journal, 156, 395–403. https://doi.org/10.1016/j.cej.2009.10.061 52. Singh, D. P., & Trivedi, R. K. (2013). Acid and alkaline pretreatment of lignocellulosic biomass to produce ethanol as biofuel. International Journal of ChemTech Research, 5, 727–734. 53. Neyens, E., Baeyens, J., & Creemers, C. (2003). Alkaline thermal sludge hydrolysis. Journal of Hazardous Materials, 97, 295–314. https://doi.org/10.1016/S0304-3894(02)00286-8 54. Liu, H., Ma, X., Li, L., Hu, Z. F., Guo, P., & Jiang, Y. (2014). The catalytic pyrolysis of food waste by microwave heating. Bioresource Technology. https://doi.org/10.1016/j.biortech.2014. 05.020 55. Silverstein, R. A., Chen, Y., Sharma-Shivappa, R. R., Boyette, M. D., & Osborne, J. (2007). A comparison of chemical pretreatment methods for improving saccharification of cotton stalks. Bioresource Technology, 98, 3000–3011. https://doi.org/10.1016/j.biortech.2006.10.022 56. Sun, X. F., Xu, F., Sun, R. C., Fowler, P., & Baird, M. S. (2005). Characteristics of degraded cellulose obtained from steam-exploded wheat straw. Carbohydrate Research, 340, 97–106. https://doi.org/10.1016/j.carres.2004.10.022 57. Saha, B. C., & Cotta, M. A. (2007). Enzymatic saccharification and fermentation of alkaline peroxide pretreated rice hulls to ethanol. Enyzme and Microbial Technology, 41, 528–532. https://doi.org/10.1016/j.enzmictec.2007.04.006

42

N. Shukla and N. Remya

58. Mishima, D., Tateda, M., Ike, M., & Fujita, M. (2006). Comparative study on chemical pretreatments to accelerate enzymatic hydrolysis of aquatic macrophyte biomass used in water purification processes. Bioresource Technology, 97, 2166–2172. https://doi.org/10.1016/j.biortech. 2005.09.029 59. Poornejad, N., Salehi, S. M. A., Karimi, K., & Taherzadeh, M. J. (2011). Improvement of enzymatic hydrolysis of rice straw by N- methylmorpholine-N-oxide ( NMMO ) pretreatment 566–570. https://doi.org/10.3384/ecp11057566. 60. Narayana, T. (2009). Municipal solid waste management in India: From waste disposal to recovery of resources? Waste Management, 29, 1163–1166. https://doi.org/10.1016/j.wasman. 2008.06.038 61. Bardos, P. (2004). Composting of mechanically segregated fractions of municipal solid waste— a review. www.r3environmental.com%5Cnwww.juniper.co.uk. 62. S.E., & Eliezer, Y. (1989). The fourth state of matter, an introduction to plasma science. https:// doi.org/10.1017/CBO9781107415324.004. 63. Leal-Quirós, E. (2004). Plasma processing of municipal solid waste. Brazilian Journal of Physics, 34, 1587–1593. https://doi.org/10.1590/S0103-97332004000800015 64. Rajasekhar, M., Rao, N. V., Rao, G. C., Priyadarshini, G., & Kumar, N. J. (2015). Energy Generation from municipal solid waste by innovative technologies—plasma gasification. Procedia Materials Science, 10, 513–518. https://doi.org/10.1016/j.mspro.2015.06.094 65. Byun, Y., Namkung, W., Cho, M., Chung, J. W., Kim, Y.-S., Lee, J.-H., Lee, C.-R., & Hwang, S.-M. (2010). Demonstration of thermal plasma gasification/vitrification for municipal solid waste treatment. Environmental Science and Technology, 44, 6680–6684. https://doi.org/10. 1021/es101244u 66. Unnisa, S. A., & Hassanpour, M. (2017). Plasma technology and waste management. Resource Recycling Waste Management, 1, 1–3. 67. Tendler, M., Rutberg, P., & van Oost, G. (2005). Plasma based waste treatment and energy production. Plasma Physics and Controlled Fusion, 47, A219. http://stacks.iop.org/0741-3335/ 47/i=5A/a=016. 68. Huang, Y., Chiueh, P., & Lo, S. (2016). Mini review A review on microwave pyrolysis of lignocellulosic biomass, Sustain. Environmental Research, 26, 103–109. https://doi.org/10. 1016/j.serj.2016.04.012 69. Suriapparao, D. V., & Vinu, R. (2015). Bio-oil production via catalytic microwave pyrolysis of model municipal solid waste component mixtures. RSC Advanced, 5, 57619–57631. https:// doi.org/10.1039/C5RA08666C 70. Miura, M., Kaga, H., Sakurai, A., Kakuchi, T., & Takahashi, K. (2004). Rapid pyrolysis of wood block by microwave heating. Journal of Analytical and Applied Pyrolysis, 71, 187–199. https://doi.org/10.1016/S0165-2370(03)00087-1 71. Qiang Chen, M., Wang, J., Xu Zhang, M., Gong Chen, M., Feng Zhu, X., Fei Min, F., & Cheng Tan, Z. (2008). Catalytic effects of eight inorganic additives on pyrolysis of pine wood sawdust by microwave heating. Journal of Analytical and Applied Pyrolysis, 82, 145–150. https://doi. org/10.1016/j.jaap.2008.03.001. 72. Wang, X., Chen, H., Luo, K., Shao, J., & Yang, H. (2008). The influence of microwave drying on biomass pyrolysis. In Energy and fuels (pp. 67–74). https://doi.org/10.1021/ef700300m. 73. Huang, Y. F., Kuan, W. H., Lo, S. L., & Lin, C. F. (2008). Total recovery of resources and energy from rice straw using microwave-induced pyrolysis. Bioresource Technology, 99, 8252–8258. https://doi.org/10.1016/j.biortech.2008.03.026 74. Lei, H., Ren, S., & Julson, J. (2009). The effects of reaction temperature and time and particle size of corn stover on microwave pyrolysis. Energy and Fuels. https://doi.org/10.1021/ef9 000264 75. Wan, Y., Chen, P., Zhang, B., Yang, C., Liu, Y., Lin, X., & Ruan, R. (2009). Microwaveassisted pyrolysis of biomass: Catalysts to improve product selectivity. Journal of Analytical and Applied Pyrolysis, 86, 161–167. https://doi.org/10.1016/j.jaap.2009.05.006 76. Wu, C., Budarin, V. L., Gronnow, M. J., De Bruyn, M., Onwudili, J. A., Clark, J. H., & Williams, P. T. (2014). Conventional and microwave-assisted pyrolysis of biomass under different heating rates. Journal of Analytical and Applied Pyrolysis. https://doi.org/10.1016/j.jaap.2014.03.012

Solid Waste Management Methods …

43

77. Himmel, M. E., Ding, S. Y., Johnson, D. K., Adney, W. S., Nimlos, M. R., Brady, J. W. & Foust, T. D. (2007). Biomass recalcitrance: Engineering plants and enzymes for biofuels production. Science (80-), 315, 804–807. https://doi.org/10.1126/science.1137016. 78. Arshad, H., Sulaiman, S. A., Hussain, Z., Naz, Y., Basrawi, F. (2017). Microwave assisted pyrolysis of plastic waste for production of fuels: a review. In MATEC Web Conference 131. https://doi.org/10.1051/matecconf/201713102005. 79. Zhang, Z., Macquarrie, D. J., Aguiar, P. M., Clark, J. H., & Matharu, A. S. (2015). Simultaneous recovery of organic and inorganic content of paper deinking residue through low-temperature microwave-assisted pyrolysis. Environmental Science and Technology, 49, 2398–2404. https:// doi.org/10.1021/es505249w

Characterization and Sustainable Utilization of Steel Slag (SS) as a Recycled Aggregates in Indian Concrete Industry Vidyadhar V. Gedam, Pawan Labhasetwar, and Christian J. Engelsen

Abstract The Indian steel industry had paramount importance and complex challenges for sustainable solid waste management generated during various operations stages. One of such emerging and aggravated solid waste management problem is Steel Slag (SS). The proposed work emphasizes the physical, chemical, mechanical, morphological, and mineralogical characteristics of SS collected from Steel Plants in India. The SS waste had different characteristics and was selected to determine their appropriateness as Recycled Aggregates (RA) instead of Natural Aggregates (NA) in the concrete industry. The detailed study comprises carbon content, Loss On Ignition (LOI), moisture content, pH, chlorides, acid-insoluble residue, X-ray fluorescence (XRF), heavy metals, particle size, X-ray powder diffraction (XRD), analysis, workability, mechanical characteristics, and compressive strength. It was identified that; various chemical, physical, mechanical and mineralogical properties of SS wastes were varying in nature. The RA’s mechanical characteristics were within the Indian standard (IS) limit (IS:6579–1981 and IS:383–1970). Further, as per IS:516–1959, SS’s compressive strength properties for M-20 grade cubes were attained in 28 days, and the strength was higher for 90 days. Thus, the proposed work demonstrates the possibility of SS waste for its use as RA and suitable alternatives for NA, particularly for construction activities. Keywords Solid Waste · Steel Slag (SS) · Mechanical and Morphological Characteristics · Natural Aggregates (NA) · Recycled Aggregates (RA) V. V. Gedam (B) · C. J. Engelsen Sustainability Management Area, National Institute of Industrial Engineering (NITIE), Mumbai, India e-mail: [email protected] C. J. Engelsen e-mail: [email protected] P. Labhasetwar · C. J. Engelsen Chief Scientist, National Environmental Engineering Research Institute (NEERI), Nagpur, India e-mail: [email protected] C. J. Engelsen Chief Scientist SINTEF Building and Infrastructure, Oslo, Norway © Springer Nature Switzerland AG 2022 S. Yadav et al. (eds.), Environmental Management in India: Waste to Wealth, https://doi.org/10.1007/978-3-030-93897-0_3

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1 Introduction Technological advancement has a significant effect on enhancing human life; however, it also generates wastes and by-products. One such byproduct is Steel Slag (SS) generated from Iron and Steel Plants, which pose a significant economic and environmental burden in India. World across, India is the 3rd producer of steel with a production capacity of around 101.4 Million Tonnes (MT) in the year 2017 [1, 2]. With a growth rate of 8% per year, the steel industry sector is expected to produce 325 MT of steel by 2030 [3]. The Indian steel production is expected to grow from 99 MT in 2013 to 125 MT in 2016, and with one ton of steel, nearly 130–200 kg of slag is generated [4]. In India, nearly 49% of the total steel is produced by route of Blast furnace-Basic Oxygen Furnace (BF-BOF) and remaining % via induction furnace or electric arc [5]. Figure 1 shows the generation of different types of Steel and Iron Slag. During liquid steel production, depending upon the hot metal quality and steelmaking process, nearly 150–180 kg of slag is generated [6, 7]. With India’s current production capacity, around 12 MT of Steel Slag (SS) is expected as a solid waste per year [8]. The SS is mostly utilized during the manufacturing of road metal and bases, asphalt paving, cement clinker, track ballast, barrier material, portland slag, landfills, remedy for waste sites, concrete aggregates, road making, railway ballast, paving bases, and patching path holes, etc. [9]. The percentage of generations of different types of slag are shown in Fig. 2. Therefore, such an enormous quantity of solid waste produced from the Indian steel industry needs to be reused for the Indian steel industry’s long-term sustainability. Considering present scenarios, there are no regulatory standards or norms for controlling and further utilizing the slag in India. However, in 2003 Environmental Ministry came up with the Corporate Responsibility Policy on Environmental Protection (CREP) policy. The initiative focused on waste minimization by 100% utilization of slag by 2008. However, India has not achieved this target due to lack of interest by end users and the voluntary nature of initiatives. Out of the total generated SS, only 25% is being reused in India [10], which is low compared to the developed nations

Blast Furnace Slag

Granulated Blast Furnace Slag Air-Cooled Blast Furnace Slag

Iron and Steel Slag

Basic oxygen furnace Slag

Steel Making Slag

Electric Arc Furnace Slag Electric Induction Furnace Slag

Fig. 1 Generation of different types of slag from Steel Industry

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Fig. 2 Percent generation of different types of slag in India

such as German, Japan, France, and the USA [11]. However, with adequate policy, technological support, and government and end-users initiatives, SS can be put to beneficial use [12]. There are a higher scope and means to find the application of SS specifically in the construction industry as a Recycled Aggregates (RA). The Indian construction industry is growing with soccer pace, and on the contrary, there is an acute shortage of Natural Aggregates (NA) for their use in the construction industry. It is estimated that; Indian construction sector has used nearly 3330 MT of total aggregates during the year 2015 and will require nearly 5075 MT of aggregates by the year 2020 [13]. Furthermore, constant quarrying of available limited natural resources for NA creates ecological impacts. Thus, the use of SS as RA in the construction industry is one of the sustainable approaches. Such RA would be a sustainable and reliable alternative to NA in the construction industry. The use of these RA will not only minimize the negative impacts on the surrounding ecosystem but will also reduce the gap between demand and supply and thereby will substantially reduce the impact on the surrounding environment [14]. The proposed work explores the physical, chemical, mechanical, morphological, and mineralogical properties of SS waste. The focus is on identifying the fundamental information about SS waste’s nature for effective, sustainable end uses. The waste material analyzed has different compositions and properties and was selected to determine suitability in the concrete industry. After detailed characterization, the study also focuses on the sustainable utilization of SS as recycled aggregates for M-20 grade concrete making.

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Fig. 3 Collection SS from slag pond of steel Industry

2 Methods and Material 2.1 Sample Collection The Bhilai and Jamshedpur Steel Plants field visits were performed, and multiple Steel Slag (SS) samples were collected directly from the slag pond. Before the analysis, the samples collected from these plants were kept in air-tight plastic drums and polyethylene bags [15]. Figure 3 shows a collection of SS samples from slag ponds. During the proposed work, an Associated Cement Companies (ACC) OPC-43 grade cement was used [16]. The fineness of the cement was 296 m2 /kg, and standard specifications [17] was used for fine and coarse aggregates. The civil engineering concrete lab tap water for making concrete samples and curing conditions was used [18].

2.2 SS Waste Characterization Methods and Parameters Analyzed 2.2.1

Sample Preparation

The collected SS waste sieve analysis was performed after collecting samples directly from steel plants, without any processing. After sieve analysis, it was noted that SS waste fractions were of various sizes ranging from 40 to 10 mm, and nearly 90% of aggregates were of 40 mm size. The collected SS waste was then analyzed for physical, chemical, mineralogical, and mechanical characteristics. After the characterization, the SS waste was used as RA for M-20 grade concrete making.

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Characterization of SS Waste Samples

Different standard methods were used for the analysis and characterization of SS waste samples. The chemical and physical characteristics of SS waste, including acid-insoluble residue, moisture content, and Loss On Ignition (LOI), were analyzed as per IS [19]. The SS waste samples’ pH was analyzed as per IS Method [20]. To determine chloride concentration, British Standard was used [21]. The concentration of sulfate ions in SS waste was determined spectrometrically (UV–VIS Spectrophotometer 118). The heavy metal concentrations of SS waste samples were determined by Inductive Coupled Plasma-Optical Emission Spectrometry (ICP-OES) (Thermo Fisher iCAP 6300 DUO) [22]. The presence of minor and major elements (chemical composition) was conducted using the X-ray fluorescence method (XRF-PANalytical PW-2403). The mineralogical characteristics of SS waste samples were performed using an X-ray powder diffraction (XRD) spectrometer (Rigaku Miniflex II). In the mineralogical analysis, various mineralogical phases were recognized using the Joint Committee on Powder Diffraction Standards (JCPDS). The sieve size analysis or particle size analysis of SS waste was performed as per IS [23]. The mechanical characteristics such as water absorption, abrasion value, impact, and crushing value of aggregates were determined as per IS [24]. The workability of the concrete mix was performed using the slump cone test. The M-20 grade compressive characteristics at 90, 28, and 7 days for prepared concrete blocks were performed as per IS [18, 25] at 0.5 water to cement ratio (w/c). The testing of compressive characteristics, mainly compressive strength, was performed as per IS [26].

3 Results and Discussions 3.1 Physical and Chemical Characteristics of SS Waste The physical and chemical characteristics of SS waste are attributed mostly depend on waste nature, manufacturing process, amount, and sampling location [27–29]. The detailed characteristics of SS waste samples are depicted in Table 1. The mobility Table 1 Physico-chemical characteristics of SS waste Sampling locations

pH

Moisture content (%)

Acid insoluble residue (% by mass)

Chloride (%)

Sulphate (mg/L)

Carbon (%)

LOI (%)

Tata steel, Jamshedpur

10.1

0.6

1.1

0.009

89.2

0.7

2.4

Bhilai Steel, Bhilai

10.3

0.7

0.8

0.021

68.4

0.5

2.5

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and leaching of heavy metals are mostly governed by solution pH, particularly in the collected samples [30, 31]. The pH of SS wastes was alkaline and varied from 10.1 and 10.2 for Jamshedpur and Bhilai, respectively. The alkaline characteristics of both the SS were notably due to oxides of Mg and Ca that may be available during steel making [27]. The SS waste samples were dry in nature with a moisture content of 0.6% for both samples. The value of acid-insoluble residues was observed to be 1.1% to 0.8%. It was also observed that; the acid-insoluble residue in SS was very low. The insoluble residue is mostly contributed from impurities in gypsum [32]. The low % of acid-insoluble residue was because of the low % of gypsum in the collected sample and vice versa. The chloride in SS may be available in various types, which include KCl, NaCl, and CaCl2 [33, 34]. However, the % of chloride was observed to be low in all samples (< = 0.02%). The value of soluble sulfate, which probably may have a potential of leached out from SS, was observed to be 89.2 mg/L to 67.4 mg/L for Jamshedpur and Bhilai, respectively. The LOI value of SS mainly includes mass loss of water, carbonates decomposition carbon loss. The LOI values in SS waste were 2.4 and 2.6% for Jamshedpur and Bhilai respectively.

3.2 Major, Minor and Trace Analysis of SS Waste The presence of minor and major element (chemical composition) in collected SS wastes are shown in Fig. 4. It can be seen that major constituents of SS waste were CaO, Fe2 O3 , SiO2 , MgO, P2 O5 , with tracest of Al2 O3 , SO3, TiO2 . Figure 4 shows that; the presence of CaO, Fe2O3 in SS wastes was higher in concentration compared to other oxides, which are mostly attributed due to the presence of more % of alite and belite in the former sample.

Fig. 4 Chemical composition of SS waste (%)

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Fig. 5 Trace element concentration (mg/kg) of SS waste sample

The heavy metals analysis of collected SS wastes is shown in Fig. 5. The heavy metals analysis was carried out because the SS wastes were mostly disposed of in slag pond, low laying area, and waste disposal sites, leading to heavy metals leaching and may lead to ecosystem damage. Figure 5 shows that; the presence of heavy metals such as Mn, Cr, V, Pb, Mo, Zn followed by As was higher, and the concentration of Hg was minimum. A substantial difference can be observed in the concentrations of heavy metals in the collected samples from the same steel plant as well as from different steel plants. The variation in heavy metal concentrations in SS samples from Steel Plants may be due to the different elements’ volatility. The variation between the heavy metal concentrations in SS can also be attributed due to different types of raw material used, the manufacturing process used, furnace temperature and condition, sampling location, amount of sampling, and sample collection.

3.3 Mineralogical Characteristics of SS Waste The XRD analysis of SS wastes samples depicts well-known peaks at 2θ degrees of 35, 25, and 20. The mineralogical characteristics of SS waste samples are depicted in Fig. 6. The mineralogical characteristics of SS waste reveal the presence of important crystalline phases. These crystalline phases include belite and alite, along with fractions of quartz, mullite, and feldspar. The earlier published literature also highlights the presence of mentioned phases [27].

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Fig. 6 X-ray Diffractogram of SS samples

3.4 Sieve Analysis of SS Waste The sieve analysis of SS waste is shown in Fig. 7. The sieve analysis of SS wastes was done after collecting and receiving the steel plants’ samples without any processing. It can be seen that SS waste fractions were of different sizes, varying from sizes of 40 to 10 mm. Further, greater than 90% of aggregates are having a size of 40 mm. The sieve analysis also reveals that; the collected SS waste can be used as recycled aggregates in the concrete making as per IS [17].

Fig. 7 Sieve analysis of SS waste samples

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Table 2 Comparative mechanical characteristics of SS waste and Natural Aggregates Type of aggregates

Characteristics of aggregates/

Impact value Crushing (%) value (%)

Abrasion Value (%)

sampling

Water absorption (%)

locations Recycled aggregates Natural aggregates

BIS:383 (1970), Specifications

SS, Jamshedpur

37

38

34

2

SS, Bhilai

40

39

36

2

Uncrushed Gravel/stone*

15

25

13

–

Crushed Gravel/stone*

20.4

23.5

–

0.5

Crushed Gravel/stone**

8.88

14.04

15.58

0.89

Crushed Gravel/stone***

17.65

18.4

–

0.29–0.3

Crushed and Uncrushed gravels

45%

45%

50%

–

National Slag Association (NSA) [37]*, Sahay and Saini [38]**, Parekh and Modhera [39]***

3.5 Mechanical Characteristics of SS Wastes The collected SS waste from two steel plants was of varied nature. The SS waste comparison and analysis for various mechanical characteristics are presented in Table 2. From Table 2. It can be seen from Table 2 that; the SS waste impact value was between 37 and 40% for Jamshedpur and Bhilai steel plants are respectively satisfying IS [17]. The observed SS waste crushing value was 38% and 39% and complied with the IS. Further, the abrasion value of SS waste was observed to be 34–36% for Jamshedpur and Bhilai steel plants, respectively, which also complying with IS [17]. It can be seen from Table 2 that the SS waste samples were found unsuitable for their use in wearing surfaces as they fail to satisfy the prescribed requirements of IS [17]. The water absorption for SS waste was observed to be 2% and was minimal due to the hard, dense nature of SS. The water absorption shall not be more than 1.5% for the material used in the surface and binder course, upper and lower base, and in the areas where the aggregates are subjected to freezing and thawing. In other areas, the water absorption limit is 2% [35]. Also, the workability of concrete mix regarding the height of subsidence (slump) was varying in the span of 120 to 90 mm.

3.6 Compressive Strength at 90, 28, and 7 Days The M-20 grade caste cubes’ compressive strengths were determined as per IS [18, 25]. The RA was replaced by SS waste with 20, 30, 40, and 50% replacement for 90,

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Fig. 8 Variation in compressive strength with % replacement of SS as RA @7, 28 and 90 Days

28, and 7 days. As depicted in Fig. 8, the required strength of cubes was obtained during 28 days for M-20 grade and was comparatively more for 90 days. Further, Fig. 8 also describes compressive strength reduction trends with an increased SS ratio as RA. The compressive strength reduction of RA with respect to NA was 9–1%, 13–6%, and 7–1%, for 90, 28, and 7 days of M-20 concrete cubes, respectively. This was most likely attributed to the hard, dense, and angular as well as roughly nature of SS [36]. The % reduction in strength also closely depends on characteristics such as the nature of RA, processing of RA, w/c ratio, replacement ratio, the grade of concrete, etc.

4 Conclusions The various physical, chemical, mechanical, morphological, and mineralogical characteristics of SS collected from Steel Plants in India were unpredictable characteristics that mostly depend on different associated factors such as waste nature, manufacturing process, amount, and sampling location. However, during the proposed work, it was seen that; the fundamental mechanical characteristics such as impact, crushing, abrasion, and water absorption values are within the limit of IS [17, 35]. Further, the compressive strengths test of SS waste for M-20 grade cubes was within IS [26], and the required targeted cube strength was achieved at 28 days and was comparatively higher for 90 days. Thus, based on the proposed work, SS waste can

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be seen as a potential for their use as a RA replacing NA, particularly in the concrete industry.

5 Recommendations The proposed work showcases the sustainable use of SS waste in the concrete industry as per IS. Based on present research as well as earlier work, we propose the use of SS waste as a sustainable and viable alternative for RA, particularly in the concrete industry. The use of SS has the potential to fill the supply gap of NA [40–42]. The study suggests using SS waste as RA, particularly for low-grade concrete (M-20) up to a replacement level of 50–30%. Furthermore, the present work gives information to decision-makers and various Indian and International steel sectors to emphasize the use of SS as an RA for implementing sustainability in the steel sector.

References 1. World Steel. (2018). World steel in figures. Available at: https://www.worldsteel.org/en/dam/ jcr:f9359dff-9546-4d6b-bed096201185b12/World%2520Steel%2520in%2520Figures%252 02018.pdf. 2. Kumar, P. S., & Naidu, V. B. (2013). An analysis of Indian steel industry. Journal of International Academic Research for Multidisciplinary, 1(3). 3. Green Rating of Indian Iron and Steel Sector, Center for science and environment (CSE). (2012). http://www.cseindia.org/content/green-rating-indian-iron-and-steel-sector. 4. Devi, V. S., & Gnanavel, B. K. (2014). Properties of concrete manufactured using steel slag. 12th Global Congress on Manufacturing and Management (GCMM). Procedia Engineering, 97, 95–104. https://doi.org/10.1016/j.proeng.2014.12.229 5. Kanchan S. (2013). Pollution and control in steel industry. Center for science and environment (CSE). 22, M12, TATA Special issue. http://cseindia.org/content/pollution-and-control-steelindustry. 6. Harichandan, B., Venugopal, R., & Dash, A. K. (2017). Implementation of mineral processing techniques to minimize waste generated in steel plant. Geominetech: The Indian Mineral Industry Journal, 04(02), 12–16 URL:http://geominetech.org/docs/2017/ebooks/ism1.pdf 7. Proctor, D. M., Fehling, K. A., Shay, E. C., Wittenborn, J. L., Green, J. J., Avent, C., Bigham, R. D., Connolly, M., Lee, B., Shepker, T. O., Zak, M. A. (2000). Physical and chemical characteristics of blast furnace, basic oxygen furnace, and electric arc furnace steel industry slags. Environmental Science and Technology, 34(8), 1576–1582. https://doi.org/10.1021/es9906002. 8. FICCI. (2018). Using steel slag in infrastructure development. Available at: http://blog.ficci. com/steel-slag/5291. 9. Indian Bureau of Mines (IBM). (2017). Slag-Iron and Steel. Indian Minerals Yearbook, Part- II: Metals & Alloys, 55th Edition, 2016. Ministry of mines, Government of India. http://ibm.nic.in/writereaddata/files/08242017152436IMYB2016%20Slag% 20Iron%20and%20STeel_Advance%20release.pdf. 10. Umadevi, T., Rao, S. P., Roy, P., Mohapatra, P. C., Prabhu, M., Ranjan, M. (2010). Influence of LD slag on iron ore sinter properties and productivity. In 6th international seminar on mineral processing technology, NML (pp. 747–757). Jamshedpur. http://eprints.nmlindia.org/2484/1/ 105.pdf.

56

V. V. Gedam et al.

11. Yi, H., Xu, G., Cheng, H., Wang, J., Wan, Y., & Chen, H. (2012). An overview of utilization of steel slag. Procedia Environmental Sciences, 16, 791–801. https://doi.org/10.1016/j.proenv. 2012.10.108 12. Federation of Indian Chambers of Commerce & Industry (FICCI. (2014). Using Steel slag in infrastructure development. http://blog.ficci.com/steel-slag/5291/. 13. JSW Steel. (2018). Innovation of the year. Available at: www.worldsteel.org/en/dam/jcr:6646634d-3d65-4051–9736–13d54dff4cdd/Steelie+2016_vfinal.pdf 14. Faleschini, F., Marzi, P. D., & Pellegrino, C. (2014). Recycled concrete containing EAF slag: Environmental assessment through LCA. European Journal of Environmental and Civil Engineering, 18(9), 1009–1024. 15. Alam, J. B., Awal, A. S. M. A., Alam, M. J. B., Rahman, M. S., Banik, B. K., & Islam, S. (2006). Study of utilization of fly ash generated from Barapukeria power plants as admixture in manufacturing of cement. Asian Journal of Civil Engineering, 7(3), 225–232. 16. Indian Standard, (IS: 8112, 1989). Ordinary Portland and Cement, 43 grade-Specification. Bureau of Indian Standards, Manak Bhavan, 9 Bahadur Shah Zafar Marg, New delhi, 110002. 17. Indian Standard (IS: 383, 1970). Specification for coarse and fine aggregates from natural sources for concrete (Second Revision). Bureau of Indian Standards, Manak Bhavan, 9 Bahadur Shah Zafar Marg, New delhi, 110002. 18. Indian Standard, (IS: 456, 2000). Plain and reinforced concrete-code of practice. Bureau of Indian Standards, Manak Bhavan, 9 Bahadur Shah Zafar Marg, New delhi, 110002. 19. Indian Standard, (IS: 4032, 1985). Method of Chemical analysis of hydraulic cement. Bureau of Indian Standards, Manak Bhavan, 9 Bahadur Shah Zafar Marg, New delhi, 110002. 20. Indian Standard, (IS: 2720, Part 26, 1987). Method of test for soil part 26, determination of pH value. Bureau of Indian Standards, Manak Bhavan, 9 Bahadur Shah Zafar Marg, New delhi, 110002. 21. British Standards (BS). (1988). Testing aggregates method for determination of water-soluble chloride salts. Method-pp. 812–117. British Standards Institution. 22. Environmental Protection Agency (EPA). (1986a). Acid digestion of sediments, sludges, and soils. USEPA SW-846, Method-3050B, United States Environmental Protection. 23. Indian standard (IS: 2386, Part-I, 1963). Method of test for aggregates for concrete, part I, Particle size and shape. Bureau of Indian Standards, Manak Bhavan, 9 Bahadur Shah Zafar Marg, New delhi, 110002. 24. Indian standard (IS: 2386, Part-IV, 1963). Method of test for aggregates for concrete, part IV, Mechanical properties. Bureau of Indian Standards, Manak Bhavan, 9 Bahadur Shah Zafar Marg, New delhi, 110002. 25. Indian Standard, (IS: 10262, 2009). Guidelines for concrete mix proportioning. Bureau of Indian Standards, Manak Bhavan, 9 Bahadur Shah Zafar Marg, New delhi, 110002. 26. Indian Standard, (IS: 516, 1959). Method of test for strength of concrete. Bureau of Indian Standards, Manak Bhavan, 9 Bahadur Shah Zafar Marg, New delhi, 110002. 27. Gedam, V. V., Jha, R. K., Labhasetwar, P., & Engelsen, C. J. (2013). A comprehensive physicochemical, mineralogical and morphological characterization of Indian mineral wastes. Environmental Monitoring and Assessment, 185(8), 6343–6352. https://doi.org/10.1007/s10661012-3029-7. 28. Gedam, V. V., Labhasetwar, P., & Engelsen, C. J. (2017). CCRs characterization and valorisation as mineral additives during cement production in India. International Journal of Coal Preparation and Utilization, 1–15. https://doi.org/10.1080/19392699.2017.1365713. 29. Gedam, V. V., Labhasetwar, P., & Engelsen, C. J. (2019). An Assessment of C&D Waste Quality and Its Recycling Potential-An Indian Perspective. In S. Ghosh (Eds.), Waste management and resource efficiency. Springer. https://doi.org/10.1007/978-981-10-7290-1_65. 30. Gupta, N., Gedam, V. V., Moghe, C. A., & Labhasetwar, P. K. (2017). Investigation of characteristics and leaching behaviour of coal fly ash, coal fly ash bricks and clay bricks. Environmental Technology and Innovation, 7, 152–159. https://doi.org/10.1016/j.eti.2017.02.002. 31. Gupta, N., Gedam, V. V., Moghe, C. A., & Labhasetwar, P. K. (2015). Temporal change in leaching of heavy metals from clay bricks and fly ash. International Journal of Engineering Technology, Management and Applied Sciences, 3(special issue). ISSN 2349–4476.

Characterization and Sustainable Utilization of Steel Slag …

57

32. Kiattikomol, K., Jaturapitakkul, C., Songpiriyakij, S., & Chutubtim, S. A. (2001). A study of ground coarse fly ashes with different finenesses from various sources as pozzolanic materials. Cement and Concrete Composites, 23(4–5), 335–343. https://doi.org/10.1016/S0958-946 5(01)00016-6 33. Bolwerk, R. (2004). Co-processing of waste and energy efficiency by cement plants, IPPC Conference, 21–22. Austria. 34. Farag, L. M., & Abbas, M. (1995). Practical limits for chorine cycles in dry process cement plants with pre-calcining and tertiary air ducting. ZKG Translation, 48(1), 22–26. 35. Indian standard (IS: 6579–1981). Coarse aggregate for water bound macadam (First Revision). Bureau of Indian Standards, Manak Bhavan, 9 Bahadur Shah Zafar Marg, New delhi, 110002. 36. National Slag Association, (NSA), (2011). Product information: steel slag base and subbase aggregates, PI 207, 25 Stevens Avenue, Building A, West Lawn, PA, 19609. http://www.nat ionalslag.org/archive/sf_prod_info_sheet.pdf. 37. Sahay, A., & Saini, G. (2010). Construction industry waste management-Experimental Case Studies of recycled aggregates. Journal of Mechanical and Civil Engineering, 43–47. eISSN: 2278–1684. http://www.iosrjournals.org/iosr-jmce/papers/AETM%2715_CE/1/8-CE168.pdf. 38. Parekh, D. N., & Modhera, C. D. (2012). Recycled aggregates fly ash concrete: An Exploratory study. The IUP Journal of Structural Engineering, V (3), 7–19. https://papers.ssrn.com/sol3/ papers.cfm?abstract_id=2172203. 39. Sonawane, T. R., & Pimplikar, S. S. (2013). Use of recycled aggregates concrete. IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE), 52–59. ISSN: 2278–1684. http://www. iosrjournals.org/iosr-jmce/papers/sicete%28civil%29-volume5/57.pdf. 40. Sharba, A. A. (2019). The efficiency of steel slag and recycled concrete aggregate on the strength properties of concrete. KSCE Journal of Civil Engineering, 23(11), 4846–4851. 41. Aparicio, S., Hernández, M. G., & Anaya, J. J. (2020). Influence of environmental conditions on concrete manufactured with recycled and steel slag aggregates at early ages and long term. Construction and Building Materials, 249, 118739. 42. Václavík, V., Ondová, M., Dvorský, T., Eštoková, A., Fabiánová, M., & Gola, L. (2020). Sustainability potential evaluation of concrete with steel slag aggregates by the LCA method. Sustainability, 12(23), 9873.

Application of Green Synthesis of Nanoparticles for Removal of Heavy Metal Ion from Industrial Waste Water Supriya Singh, Pratibha, Vanshika Singh, and Sudesh Kumar

Abstract One of the serious concerns today is the contamination of the environment from heavy metals. Their persistent nature makes the toxicity of heavy metals area of chief concern. There are various kinds of conventional methods such as adsorption, ion exchange, sulfide precipitation, etc. are available for removal of pollutants, but due to their excessive cost and time taking factor the area of interest has now shifted to the time and cost-effective technologies. Greener approach is gaining interest these days. Keywords Heavy metal toxicity · Adsorption · Ion exchange · Green synthesis

1 Introduction 1.1 What Are Heavy Metal Ions? Heavy metals are the naturally occurring elements on the crust of the earth, which have high atomic weight and a density relatively higher [1]. These elements are said to show some toxic effects at very low concentrations. The atomic weight of heavy metals falls in the range of 63.5–200.6 g mol−1 . Heavy metals cannot be destroyed. These metals enter the human body in trace amount [2]. Some heavy metals are crucial for the living form and are major elements in the bodies of living forms, whereas many heavy metals are found in traces [3]. Some of the heavy metals are Arsenic, Lead, Zinc, Mercury, Copper, Nickel, and Cobalt.

1.2 Toxic Effect of Ions Toxicity of heavy metal ions could be defined as the extent to which these can harm the living forms [4]. When talking about toxicity it is essential to know the source S. Singh · Pratibha · V. Singh · S. Kumar (B) Department of Chemistry, Banasthali Vidyapith, Vanasthali 304022, Rajasthan, India © Springer Nature Switzerland AG 2022 S. Yadav et al. (eds.), Environmental Management in India: Waste to Wealth, https://doi.org/10.1007/978-3-030-93897-0_4

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Fig. 1 Bioaccumulation [4]

HUMA NS PLANTS AND

METALS

ANIMALS

PLANKTONS MICROORGANISMS INORGANIC NUTRIENTS

of contamination, the extent of exposure and the species undergoing contamination. The effect of toxicity is seen differently on different living forms such as animal life and pant life. Higher exposure level to these elements can be lethal to human beings. Another important phenomenon associated with toxicity is bioaccumulation (Fig. 1) [4]. Bioaccumulation is the process where the heavy metals tend to deposit in the body of living forms over time. The concentration of heavy metals in the living organism is more than that in the environment. They tend to accumulate, hence the term bioaccumulation. These elements are excreted through the human body, but this process takes much time. The body passes them to the excretory organs such as kidney and liver and they tend to be stored there to be excreted gradually [5]. Excretion of heavy metals is a very slow process, and in the process they start damaging the organ.

1.3 Industrialization and Deposition of Metal Ions in Water Industrialization has been releasing many contaminants in the environment. Predominantly the development of industries such as mining ad metallurgical has contributed to the surface and subsurface contamination [6]. The increase in population has led to an increase in demand for goods which lead to industrialization. The discharge of effluents by the industries in the environment is foremost concerning. The industrial waste water should be treated before discharging it into the environment. Some of the treatment methods could be adsorption, reverse osmosis, bio sorption, etc. Reusing and recycling can reduce the amount of waste. Industries contributing to the heavy metal ion contamination are mining, electro plating, metal smelting, etc. Heavy metal ion contamination can also be due to natural phenomena such as volcanic eruption and geographical feature also add up to contamination [7]. The discharge of heavy metals into aquatic systems has been a matter of worldwide concern over the last few decades. These pollutants are introduced into the aquatic system significantly as a result of various industrial operations. Over a few decades, the community is devoting concentrated efforts for the treatment and removal of heavy metals in

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order to combat this problem. Nowadays, with the exponentially growing population the need for monitoring heavy metal discharges into the surroundings is even more prominent. This is best done right at the source of such discharges, before toxic metals pass in the multifaceted ecosystem. To follow the outcome of metallic species once they move in the ecosystem turn out to be very challenging and they start to inflict the damages as they move through from one ecological trophic layer into another. They accumulate in living tissues all over the food chain, which has humans at its top. The danger multiplies and humans eventually tend to receive the problems associated with the toxicity of heavy metals pre-concentrated and from many different directions. The resulting health problems demonstrate themselves on the acute as well as chronic levels and are reflected in the well-being of individuals and society’s spiralling health care costs.

2 How Heavy Metal Ions Affect the Environment Heavy metals are found naturally and over the time their deposition in the soil and water has caused a poisonous effect on the living forms [8]. Often the heavy metals are known to be harmful but sometimes even the lighter metals also show toxic effects on the living forms. People are frequently exposed to metals in the environment. Water is the most essential and basic resource for all the living forms [9]. It is important to maintain the sanitation and purity of water around us. Chemical pollution has affected both aquatic and human life [10]. Fresh water not only serves the purpose of drinking it affects the living at various steps. Poor water supply and sanitations have cause death of about 5000–6000 children daily [11]. Water contamination has not only affected the health, but has also caused social and economic effects. Chemical contamination has depreciated the marine ecosystem [12]. Here we would be briefly discussing the adverse effects of a few of the heavy metals: • Cadmium: Cadmium is said to possess similar chemical properties to zinc. The rich source of cadmium is sedimentary rock [8]. Its essential nutrient for all the living forms of life. Track of exposure is generally through inhalation, smoking cigarettes, or through food. Once it has entered the body of a living system, this cannot be removed easily. Long term exposure can cause lung cancer, bone obstructive disorder and increased blood pressure [13]. Through blood and urine, we can determine exposure to cadmium. Blood represents the recent contamination, whereas urine tests describe longer exposure [14]. • Chromium: Chromium is used in paints and cement [15]. In humans short term exposure has said to cause skin irritation, while the long term exposure has resulted in liver and kidney failure. It tends to get accumulated in the aquatic life. Cr (VI) causes toxicity in various organs.

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• Lead: This meal is bluish-grey in its appearance [16]. Anthropogenic activities have resulted in the accumulation of lead in the environment [17]. The source of exposure to lead is mainly due to deteriorating household paints. Lead affects developing fetus and infants more than adults. The damage on exposure occurs in the reproductive tract, gastro intestinal tract, liver and kidney. Lead also shows its toxic effects through biochemical processes, where it inhibits and mimics actions of some useful ions in the body [18]. During lead toxicity cellular damage occurs as reactive oxygen species (ROS) are formed [18]. • Mercury: Mercury is used in electrical industries. Mercury is found in three forms in the environment. It is one of the most widespread toxicants of environment. Mercury exposure has carcinogenic effects. The free ions also bring along conformational changes in the proteins. • Manganese: Manganese is a heavy metal with atomic no. 25. It is commonly used in the alloys to increase the strength, in paints industries; ceramics, etc. prolonged exposure causes neurological damage, and may also result in Parkinson’s disease.

3 Water Pollution: Determining the Quality of Water and Factors Inducing Toxicity Fresh water sources are the most important sources of water [19]. It is important for every living organism to have access to fresh drinking water. Water quality refers to the suitability of water to fulfill the various uses in day to day life [20]. Water quality is influenced by both natural and human activities. Earlier in the 1940s, the wastewater was due to municipal waste, but later on, after the industrialization, the water has been contaminated by heavy metal ions, as the industries continue to dump the effluents in the water bodies [21]. Every year the chemical contamination is increasing and new compounds are added to waste water [22]. The reason behind increasing, water pollution may be illegal disposal of waste, accidental discharge or state of unawareness. Due to the rapid increase in the contamination of water, strict rules have been passed in order to maintain the water bodies chemical free. A higher concentration of metals has made water metalliferous [8]. The pollution from any source could be monitored and controlled. The more the water is contaminated, the less would be the quantity of oxygen. Contaminated water also implies that the temperature is higher, and the pH is also affected. A balanced pH is a necessity for aquatic life. As the temperature is increased, it results in faster metabolism of the aquatic fauna.

3.1 Acid Mine Water This is an inescapable byproduct of mining where the pH of water is less than or equal to two [23]. The water is contaminated by heavy metal ions and sulfates. Since

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the water is very toxic, it needs to be treated first and then disposed off. The acid mine water is first neutralized. The neutralization procedure is carried out with lime. Acid mine water undergoes treatment in several steps. The savmin process involves 5 step treatments. Calcium carbonate provides an alternative method for neutralization of acid water. Treating water with lime is much more costly method and it requires longer reaction periods.

3.2 Toxicity Toxicity of metals occurs when there is prolonged exposure [24]. Exposure to heavy metals has resulted in brain damage, cancer, restricted growth, etc. [25]. Certain metals results in the development of autoimmunity; in this situation the person’s immune system attacks its cells. Elevated exposure can cause irreversible brain damage. Toxicity is affected by both concentration and the duration of exposure. Metal pollution also affects the fauna of water bodies. Toxicity varies from metal to metal. With the help of toxicity data, one can monitor the amount of pollutants being disposed off and correct measures to be taken to treat the effluents before dumping. Toxicity could be classified as [26]: i. ii. iii.

Lethal toxicity Acute toxicity Chronic toxicity Lethal toxicity refers to the results occurring at the end of life forms. Acute toxicity is the study of harmful effects in short duration. Whereas, chronic toxicity is the measure of harmful effects over longer durations.

4 Using Green Chemistry for Removal of Metal Ions—Brief Overview Recently efficient methods have been discovered to manufacture nanoparticles from green chemistry. The main reason for the demand for green chemistry was to develop eco-friendly technique. The contamination of water is a threat to the environment and a topic of worldwide concern [27]. The security of the environment is in danger with the increase of contaminants produced in the various types of industries. Biosynthesis of nanomaterial using plant extract is a more suitable method and environmentfriendly as it provides an alternative to the harmful chemical based methods [28]. Synthesis of nanomaterial from any plant extract is cost effective and an economical method [29]. The plant extract act as reducing and capping agents in the synthesis procedure [30]. Plants have been reportedly shown better results in the reduction of toxicity effects of metal [31]. Removal of metals through bio-sorption showed

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very promising results and it has gained attention. It was stated that iron oxide nanoparticles are using alfalfa biomass. The biological synthesis of gold and silver nanoparticles using inactivated plant extracts has been proved to be a sustainable alternative to the chemical industries. The plant extracts usually provide two-way function acting both as capping and reducing agents. Plants have shown greater results in detoxification of heavy metal accumulation [32]. Trace elements are very toxic even when present in small amounts. The use of biomass for removal through aqueous solution has shown promising results. Synthesis of nanoparticle using plant material is a very operational and non-toxic method.

5 Conventional Methods for Removal of Heavy Metal Several purification techniques have been provided for the purification of water, such as chemical physical and biological. Municipal sewage treatment plants are not designed and fitted out for control of noxious wastes. Metals and their fatality stick at even in the sledges and by-product streams of municipal sewage treatment plants. Heavy metals must be uninvolved at the source in a specially planned ‘pretreatment’ step. This precise treatment needs to be inexpensive because it most every so often deals with huge volumes of run-offs. The release standards tighten; they are becoming increasingly poorer. On the other hand, improved technologies are more expensive and often just not achievable. The search is on for effective and predominantly cost-effective cures. Some of the chemical technologies could be listed as follows: i. ii. iii. iv. v. vi. vii. viii.

Chemical precipitation Electro Floatation Adsorption Ion exchange Leaching Hydrolysis Chemical extraction olymer micro encapsulation

Now let us study some of them in detail.

5.1 Chemical Precipitation This is a simple method to treat waste water contaminated with heavy metal ions [33]. It involves the use of many chemicals to reduce the level of contamination of from metal ions for discharge [34]. In this process the chemical precipitating agents react with metal contaminants to convert them to insoluble solid particles. Then

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through sedimentation and filtration, the insoluble part is filtered. Tuning of pH is of crucial importance. After adjustment of pH, the metal ions are changed to dissolved solids by reacting with precipitating reagent. Some compounds need to be reduced or oxidized before precipitating.

5.2 Sulfide Precipitation Sulfide is used to precipitate metal ions and the sludge produced is discarded from gravity settling [35]. Due to the toxic effects of sulfide ions, this method demands pre and post-treatment and precise control over the addition of chemicals. The most commonly used chemicals used as precipitating agents are lime and calcium hydroxide.

5.3 Ion Exchange The ion exchange process is established on the reversible tradeoff of ions between solid and liquid phases [36]. The process begins with the ion-exchange reactions followed by absorption of heavy metal ions. Then a complex is formed between counter-ion and functional group. Factors affecting ion exchange are pH, temperature, time of contact, and concentration of adsorbent and sorbate ion exchanger.

5.4 Adsorption It is the process of collection of soluble substance on the appropriate interface [37]. Adsorption is one of the finest technologies for cleansing of water because its use is easy. An adosrbate is provided upon which the solutes are allowed to accumulate. The adosrbate is porous film like structure. The solutes which are to be adsorbed can be both gaseous or liquids [38]. This process ensures maintaining the reuse standards of water. Adsorption is a mass transfer process where the metal ions are transferred to sorbent and then they are bound by physical or chemical interactions [39]. The adsorbents offer better surface are. Some of the most used adsorbents are carbon Nano tubes (CNT), activated carbon and saw dust. Few of the basic characteristic of the conventional adsorbents are as follows [40]: i. ii. iii.

Low cost High surface area High capacity of ion exchange.

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Activated Carbon

Activated carbon is produced from agricultural products. These are used for removal of heavy metal ions [41]. Studies have found that in order to remove Ni ions, carbon prepared at 900. C gives better results. 100% Ni was obtained in the pH range of 2–5.

5.4.2

Carbon Nano Tubes

CNT show greater efficiency in removing toxic metals. They consist of sheets of graphene which further forms a cylinder [42]. The length of cylinder does not exceed the range of 20 µm. Once they are immobilized with calcium alginate, the risk of CNT discharge in water is reduced. The results for CNT are 74.8%.

5.5 Disadvantages of Conventional Methods of Heavy Metal Removal These techniques are easy to carry out but they pose a great risk to the environment, as they demand great-monitoring. When used at large scale, the conventional methods are not economical. These old techniques do not get accurate results as the latest technology, and the use of expensive chemicals has posed a threat to the environment [43].

6 Methods to Remove Deposition of Ions from Water: Nano Technology As the population increases and the pace of industrialisation is also rising, the demand for fresh water is rising throughout the world. The fresh water sources are on a decline, so it’s essential for us to make efforts to maintain the standards for fresh water. Researches are going on across the globe to come up with efficient methods to treat the waste water. After great efforts and studies, it was found that Nanotechnology is considered to be the most effective method for the treatment of water related problems, both commercially and non-commercially [44]. A favourable application of nanotechnology is in the field of water purification [45]. In order to maintain a healthy pollution free environment scientist have worked on many aspects of nanotechnology for wastewater treatment. Nanotechnology for water and wastewater treatment is growing day by day. These methods are more commercial, less tiresome with very less waste generation than conventional bulk material based methods. Various kinds of nanomaterial are available to meet the demands for treatment. Nano fibres are used for filtration purposes because they possess small pore size

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[46]. Other Nano materials are also available, for example Nano sorbents, Nano adsorbents, carbon Nano tube, dendrimers.

6.1 What is Nanotechnology? Definition: The technology which is useful or applicable for material having at least one dimension in the range of 1–100 nm. To simplify this definition, it could also be rephrased to “technology on nanoscale” [47]. The range is known as Nano region [48]. The word Nano comes from a Greek word Nanos which means dwarf [49]. Nano on the scale lies in the region of 10–9 . Nano technology has introduced unique Nano materials into the environment. Nano particles attract the interest due to their extremely small size, and large surface to volume ratio [50]. Design of materials is controlled by controlling the shape and size of materials. The materials should not exceed their size limit from Nano scale. Nano materials exhibit properties based on their shape and size. In Nano materials, their small size ensures that more atoms would be near the interface.

6.2 Classification of Nano Materials [51] 6.3 Fabrication Methods Nano material’s fabrication follows two steps. These are [52]: i. ii.

Top-down method Bottoms up method

A hybrid of these two approaches is known by the name lithography [53]. This method is used for the development of thin films. The most preferred method among all these is bottom up method. A bottom-up method is a conservative method where atoms add up to each other to form a molecule and then cluster. Gibbs free energy drives bottoms up process, and it is in a state of thermodynamic equilibrium. Due to the presence of fine structures and large surface area Nano particles have high efficiency in the field of water purification. The presence of large surface area has a great advantage in the removal of microbes. The reasons for the success of Nano technology is [54]: • • • •

High absorbing Nano materials. High reacting capabilities. The large surface area due to small size. More interacting surface.

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6.4 Kinds of Nanomaterials Many different kinds of Nano material have been used in the removal of heavy metal ion from waste-water, such as Nano sorbents including carbon Nano tube, dendrimers. Various uses of different nanomaterial can be detailed in various stages:

6.4.1

Nanosorbent

Nano sorbents comes with extremely high sorption capacity [55]. They are used both for commercial and non-commercial purposes. Being highly efficient, they are useful in the treatment and remediation process of waste water. Regenerated Nano sorbents are used for commercial purposes because they are cost-effective. Some examples of Nanosorbent are: • Nano clays • Carbon-iron • Carbon-based Nano adsorbent. 6.4.2

Nano Catalysts

Nano catalysts are the Nano materials which increase the catalytic activity at the surface, and it also increases the degradation process. Nano catalysts are carrying shape dependent properties [56]. Silver Nano catalysts are efficient in removing microbial contamination. It enhances the reactivity and degradation of environmental impurities such as organo—chlorine pesticides, halogenated herbicides azo dyes, polychlorinated biphenyls, and nitro aromatics.

6.4.3

Nano Adsorbents

Nano adsorbents have a wide range of application such as catalytic, absorptive, catalytic membrane, bioactive nanoparticles, biomimetic membrane, etc. Nano adsorbent possesses micro pores, thermal stability, mechanical stability, and large surface area [57]. The various kind of Nano adsorbents proposed is Nano tubes, nanomesh nanoporous ceramics, and Nano filtration membranes. For metal ion removal carbon Nano tubes act to be good adsorbent as they have the hollow the surface area and they act as good adsorbents. The adsorption capacity could be easily increased by altering the temperature. Since nanotubes are hollow inside, they provide an easy and faster flow rate.

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Nanomesh

Nanomesh is a modification of nanotubes. This is obtained by joining nanotubes on a flexible porous material which is having the capability to attach one functional group. Various kinds of functional groups are used to remove different types of contamination. For example nanotube coated with alumina is said to remove Pb from industrial effluent. Carbon nanotubes are functionalized by adding functional groups like hydroxyl, carbonyl and carboxyl.

6.5 Water Remediation Using Polymer Nanoparticles The statistics for water on earth crust reveal that only 0.08% is available as fresh drinking water, and only 30% is not trapped in the form of glaciers [58]. With the increase in the water bodies concern for water treatment is a burning topic. The development of water technology can be very helpful in the treatment of water quality. Polymeric Nano particles have various uses in the treatment of water [59]. Based on the principle of micelles, Nanoparticles possess amphiphilic properties i.e. these molecules have two parts hydrophobic and hydrophilic [60]. The application of polymeric Nano particle offer solution commonly used a surfactant to increase the tremendous remediation of organic contaminant.

7 Removal of Heavy Metal from Industrial Waste Water Using Bio Based Materials Inventive developments for treating industrial wastewater holding heavy metals often. Include technologies for lessening toxicity in order to fulfil technology-based treatment standards. It is obvious from the survey that new adsorbents and membrane filtration are the most frequently studied and widely applied for the treatment of metal-contaminated wastewater. Existence of heavy metals in the marine systems has become a severe problem. Bio sorption is one such evolving technology. The objective of the study was to make use of locally available agricultural products. Bio sorption of heavy metals from water is a rather new process that has demonstrated very positive results in the deduction of toxins from aqueous effluents [61]. The major advantages of bio sorption technology are its effectiveness in reducing the concentration of heavy metal ions to very low levels and the use of inexpensive bio sorbent materials. The benefit of bio sorption is that it uses biomass raw resources which are either ample (seaweed) or wastes from other industrial processes (fermentation wastes). The biomass has unique capabilities to concentrate and immobilise that depends to a certain degree on [62]:

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the type of biomass, the mixture in the solution, the type of biomass preparation, the physio-chemical process in the environment.

Agricultural wastes area rather complex processes affected by several factors. Heavy metal ions are described as priority pollutants, due to their freedom of movement in natural water ecosystems and due to their toxicity. Agricultural by-products are made up of lignin and cellulose. They may contain some functional groups such as alcohol, ketone, aldehydes, etc. These can bind to heavy metal ions and donate an electron from complex to the solution.

7.1 Ligni i. ii. iii. iv.

Aromatic Three-dimensional polymer Covalently linked with xylans and galactoglucomannans Chemically resistant.

7.2 Composition of Leaves Leaves from the different tree are collected because they contain a variety of different organic and inorganic compounds. Some of the chemical compounds in the cell wall which make important sorption sites are: i. ii. iii.

Cellulose Hemicellulose Pectin. Pigments in leaves which act as active metal sorption sites are:

i. ii. iii. iv.

Chlorophyll Tannin Anthocyanin Carotene.

Adsorption has been found out to be the most effective way to treat industrial wastes. Its easy availability and inexpensiveness have made it a widely used technique. The discovery of biosorption technique happened to be because there was a demand for a chemical based technique and not chiefly a biological one. To prepare appropriate bio sorbent materials from industrial waste biomass. The steadiness of the biomass will have to be changed. Generally, the industrial biomass looks like wet mud, dry cake powder. This need to be treated and converted to granules which are

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durable and small so that the sorption process is resisted. Seaweed possesses macro structures and excellent sorbing properties. Using seaweeds as resources could turn out to be an economical process. For bio sorption to occur a solid phase (sorbent) and a liquid phase (solvent) are require containing dissolved species to be sorbed later. Metal ions showing high affinity for sorbent are bound by complex processes such as chemisorption, in exchange, adsorption by physical and chemical forces.

8 Removal of Cu and Al from Drinking Water Heavy metal contamination has been one of the serious concerns across the globe. A trace amount of heavy metals is required by the body, but when the value crosses the threshold, it becomes deadly for the environment and the living forms that are in its contact. In the present day, heavy metal abundance is found in soil, air, and water [63]. Accumulation of these heavy metals declines the physical and mental health of the person. Heavy metals are also carcinogenic; longer exposure should be prevented and avoided [64]. Heavy metals occur mostly in a reduced state in ground water. Some natural physical conditions could lead to natural occurrence of heavy metals in the ground water. Maximum contaminant level (MCL) is a term used to define the maximum amount of contamination of heavy metal in the water, which can be potentially harmful for the human body [65].

8.1 Copper Copper is a transition metal, and is found to exist in monovalent and bivalent forms. Copper when present in metal imparts a bitter taste to it-, It is present in the form of sulfate and chlorides [66] • • • • • • •

Transition metal Atomic number-:29 Occurrence: monovalent and bivalent forms. Melting point-: 1357 K Boiling point-: 2835 K Properties: malleable and ductile Uses-: wiring, utensil, fertilizers, fungicides, insecticides.

The main source of copper entering the human body is through food chains, air, and water [10]. As studies have shown that the lethal dose of copper lies between 4 and 400 mg of copper lies between per kg of the body wait [67]. Copper is an important and crucial metal. Copper is known for being one of the most toxic metals known earlier. The copper pollution is becoming a serious issue of concern because

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its non-biodegradable which makes it accumulate in the food chain. The sources of copper pollution have been the mining industries, refineries, fertilizer industries, industrial effluents.

8.1.1

Copper Toxicity

Copper concentrations in drinking-water often increase during distribution, especially in systems with an acid pH or high-carbonate waters with an alkaline pH. Ingestion a of large amount of copper is risked with Wilson’s disease [67]. Wilson disease is an autosomal recessive disorder that leads to copper toxicity. Because copper accumulates in the liver, brain, and eyes. Wilson disease affects the Hepatic intracellular transport of copper and its subsequent inclusion into Ceruloplasmin and bile. Copper causes digestive disorders. Copper has its effects on gastro intestinal tract and kidneys. Some skin related disorders have also been observed, such as eczema. Workers working in the fungicide industries have been observed with the respiratory disorders known as vineyard sprayer’s lungs. This on later stages may lead to lung cancers.

8.1.2

Techniques for Removal of Copper

The following are the techniques to remove Cu from water:

Precipitation Copper could be removed effectively through precipitation with lime as its metal hydroxide. The reaction follows is given below [68]: Mn+ + nOH− = M(OH)n The reaction is controlled by the pH of the solution, because metal ions may get precipitated over a selective range of pH.

Ion Exchange Ion exchange is an economical method for the removal of heavy metal ions [33]. To recover water from electroplating, it is a suitable method, but as a whole ion exchange is very costly because it involves recharge of resins.

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Adsorptions Adsorption is a significant technique for the treatment of heavy metal contamination. Adsorption is a low maintenance process. The adsorption involves the accumulation of substance at the interface. The interface could be liquid–liquid, gas–liquid, liquid– solid, etc. the matter which gets concentrated is called adsorbate and the material which gets adsorbed is termed as adsorbent. The most commonly used adsorbents have been activated carbon, fly ash, coal, coal, alumina, etc.

8.2 Aluminum • • • • • •

Atomic number-: 13 Atomic mass-: 26.98 Color-: colorless Occurrence-: silicates, oxides, hydroxides. Melting point-: 933 K Boiling point-: 2740 K.

8.2.1

Uses

The chief use of Aluminum is found in the automotive industry, electric industry, and in alloys [69]. Aluminum is also used in the cooking industries in the manufacture of utensils and foils for packaging food items. Aluminum has also been traced down in the pharmacology industries in preparation of antacids, antidepressants and food additives.

8.2.2

Sources

Aluminum sulfate and Aluminum chloride are used in drinking water treatment [70]. The use of potash alum in purifying water is often the main cause for dissolved concentrations of Aluminum. It increases the concentration of Aluminum in water then it was. The concentration of Aluminum has rapidly increased over the increase mainly due to two reasons; first being acid rain, which has caused Aluminum contamination in fresh water sources. Aluminum could reach the human body through food, air, and water. Aluminum is soluble in the pH range of 5–6 in pure water. Aluminum is found to have lethal effects in the form of arthritis, skin problems, ulcers, vomiting. Aluminum exists in trivalent oxidation state. It has a great polarizing effect, so it is difficult to find it in free form. It being strong hydrolyzing in nature finds difficulty to get soluble in the range of 6.5–8.5. The solubility increases in the acidic range.

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Removal of Aluminum

The conventional methods of heavy metal treatment such as floatation, filtration, flocculation, etc. are applied once the pH correction is done. It was studied that cation exchange resin and reverse osmosis can remove about 90% of all Aluminum present in the drinking water. Whereas chemical oxidation and anion exchange are ineffective for the removal. The efficiency of various processes for aluminum removal has been listed in Table 1.

9 Removal of Specific Metals: Zinc and Cadmium Industrialization and urbanizations have been a chief source of raised levels of heavy metal contaminations. The accidental release or carless discharges of heavy metals into biological forms have resulted in damaged ecosystems [72]. Heavy metals such as Cu, Zn, Fe, etc. are useful for the working of biological systems, but when they cross a threshold value, they become toxic. Removal of cadmium is one of the chief most priority of the health concerns presently [73]. The regulatory bodies working in order to maintain a contamination free environment has set down the limits for heavy metal discharge. Once the discharge level crosses the value prescribed, they become toxic for the environment and start affecting the environment around.

9.1 Cadmium Cadmium is one of the kinds of heavy metal that does not have any use for the living organisms. Cd is known for the harm it causes once accumulated in the food chains, causing a threat to the health of living beings. It occurs in the environment Table 1 Method for removal of aluminum from water [71]

S. No

Process

Efficiency

Remarks

1

Aeration and stripping

0–20%

Poor

2

Coagulation and sedimentation

0–60%

Fair

3

Lime softening

40–70%

Fair to good

4

Ion exchangeanion resin

0–20

Poor

5

Reverse osmosis

90–100

Excellent

6

Ultrafiltration

7

Chemical oxidation

Insufficient data 0–20

Poor

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through human interferences such as industrializations and agricultural activities [74]. Cadmium is found in the aquatic environment in the colloidal form or the dissolved form. Cadmium has the most toxic effect on human life as its removal is not possible, once it has entered the system it keeps on accumulating. Several technologies have been used for the removal of heavy metals. These are discussed below:

9.1.1

Membrane Filtration

Membrane filtration methods contain elements at the Nano scale. The membranes partition the dissolved salts and the bulk solution. Transport is described in terms of flow through a homogeneous material.

9.1.2

Phytoremediation

Bioremediation is the process where plants and micro-organisms are used for the treatment of pollutants from environmental matrices. Microbe assisted bioremediation is prevalent these days for removal of heavy metal removal. The traditional methods of purification may have some adverse effects on the environment, and also they are not cost effective. Phytoremediation of heavy metals is a cost-efficient technology. Plants used for this technique are mostly genetically modified plants, grass, woody species, etc. The biomass generated in the phytoremediation process remains very limited, all the biomass could be utilized in the formation of fertilizer, or for the bio gas production.

9.1.3

Electrocoagulation

The process involves the presence of anode and cathode where oxidation and reduction take place. Electrocoagulation is a cost-effective process and the other favorable factor here is it is easy to handle. Electrocoagulation is a fast and effective technology [75].

9.2 Zinc Zinc is one of the kinds of heavy metal which is required by the body for its proper functioning. The physical properties of Zinc are it is blue in color and solid in appearance. It has atomic no. 30. Zinc is responsible for the functioning of more than 200 enzymes in the body [76]. Zinc contamination can be linked to both human activities and artificial sources such as mining activities, power stations that are coal fires, runoff water and industrial wastes [77]. High zinc can cause health-related

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Table 2 Concentration of Zn in industrial waste water [78]

Industrial wastewater

Average concentration (mg/L)

Copper smelter

50–300

Electroplating

9–41

Hot dip galvanising

81–86

Rubber thread

81.6

Battery

0.18–7.27

Paint

20

Pharmaceutical

0.12

problems such as vomiting, skin disorders, stomach cramps. Among various available methods for removal of heavy metals from waste waters, the one most effective for zinc is adsorption. The data of average concentration of zinc in industrial wastewater has been listed in Table 2.

9.2.1

Techniques Available for Removal of Zn from Water

The treatment of industrial wastewater is a serious issue faced by environmentalists. The industrial wastewater comprise of impurities of oil, metal ion, powdered chemicals, organic pollutants, etc. Fig. 2 lists out different physio-chemical techniques for removal of zinc [79] (Fig. 3). Adsorption is one of the most economical methods for the treatment of heavy metal ions. It is essential to keep track of the cost of the materials used as sorbents. Once the material is discarded the regeneration of the adsorbent is not expensive. Therefore waste materials are preferably utilized. Any adsorbent which is easily available in

0D Nano materials

•exhibits quantum confinement in all three dimensions. Quantum dots represents the 0 D nano materials.

•Those materials where one axis is longer than the Bohr exciton radius are termed as 1 D nano materials. 1 D Nano materials •Hole and electron can freely move in one dimensions. •Here the crystalline size is negligible in one dimension •Free propogaon is allowed in two dimensions. 2 D Nano •Eg.- super thin films, nano layers, etc.

materials

3D Nano materials

•3D Nano materials are those which are formed by two or more materials with disncve properes, these are known as hierarchial structures.

Fig. 2 Classification of nanomaterials

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Chemical precipitation

Electrochemical treatment

Techniques

Activated carbon asorption

Floatation

Fig. 3 The available techniques for removal of Zn from water

the environment and the one which could be easily processed are termed as low-cost. Adsorption by activated carbon is a useful technology when it comes to the removal of heavy metals. Activated carbon is a versatile adsorbent. Activated carbon is produced by activated dehydration, carbonization which is followed by activation and then we obtain activated carbon. Some of the applications are restricted to activated carbon.

9.2.2

Agricultural Waste Adsorbents

There is various non-living plant material such as egg shell, gram husk, citrus peels, etc. which act as good adsorbents. These have a large surface area and have high mechanical strengths. Acid-treated peels show better adsorption capacities. These peels could be used further for regeneration and removal of the heavy metal ion. HCl treated carrot residues were very effective in the removal of zinc. Acid treatment was carried out for the removal of plant pigments such as resins, tannins, colored materials, etc. This adsorption was possible due to the cation exchange properties of the residues. Kinetic studies revealed that more than 70% of the ions were removed in the first treatment.

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10 Toxic Effects on Health Heavy metals are reserved under environmental toxin due to their toxic effects on biodiversity [31]. The aquatic system gets polluted with a variety of contaminants produced from varied sources (industries, agricultural and domestic). In the midst of the contaminants pesticides, heavy metals, and detergents are the main source of concern. Heavy metals are the group of 19 metals which have similar physical and chemical properties. Out of these 19 heavy metals lead, cadmium, and mercury have no biological significance, they are just known for their toxicity. Other metals are chromium, copper, manganese nickel, tin and zinc once spread in the environment then they cannot be recovered. Hence the environmental effects of metal pollution are said to be permanent. Metal pollution has a harmful effect on biological systems and does not undergo biodegradation. Heavy metals, despite no biological importance, tend to be accumulated in the body for a long time poses a threat to the body. These metals interfere with the normal functioning of the body. Based on the extent of accumulation and hazardous effects, toxicity would be classified as acute and chronic. Most commonly found heavy metals in water are arsenic, copper, lead, zinc, mercury, etc.

10.1 Toxicity Mechanism of Some of the Heavy Metals 10.1.1 i. ii. iii. iv. v.

vi.

Cadmium

Atomic number: 48. It is very toxic in the ionic form. Uses-: cadmium is used as a stabilizer in the PVC product, colouring pigments, rechargeable batteries [80]. Source of exposure: coal burning is the chief source of environmental cadmium, and inhalation and ingestion of smoke [81]. Health effects: Cadmium once absorbed is retained in the body throughout life. Cadmium exposure causes kidney damage and pulmonary risks. Long term exposure can result in damage of the skeletal system. The damage of skeletal system was first observed in Japan, where in 1950 the ouch-ouch disease was widespread. Mechanism of cadmium toxicity: cadmium shows the capability to bind with cysteine, histidine, aspartate, glutamate ligands and which results in a deficiency of iron Cadmium act as a radical scavenger. Cadmium carries the same oxidation state as zinc, and hence, cadmium can replace zinc in metallothionein [82].

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79

Mercury The atomic number of mercury is 80 Physical properties: it is a shiny silver substance. Odourless and liquid. When heated, it becomes colourless. Occurrence: Occurs in aquatic systems which are consumed by both aquatic animals and they further accumulate in humans. The three basic forms of occurrence are: • Metallic element • Inorganic salts • Organic compound

iv. v.

vi.

vii.

10.1.3 i. ii. iii. iv. v.

vi.

vii.

Mercury (Hg) is usually recuperated as a by-product. Uses: Hg was used in ancient Greece as a cosmetic. It also had used in the field of medicine in the treatment of syphilis. Metallic mercury is used in the thermometer. Health Effects: Higher intake of mercury leads to coronary heart disease. Methyl mercury causes numbness in hands and feet, and a consistent higher dose may lead to death. Mercury in amalgam causes various disease and symptoms called amalgam disease [83]. Mechanism of mercury toxicity: Hg causes disruption of membrane potential and interrupts with cellular homeostasis. It binds to thiols which are available in the free form. Hg also affects the integrity of; it is associated with the disappearance of ribosomes and removal of Endoplasmic reticulum (Fig. 4). Lead Atomic number of lead is 82. Physical properties: the melting point is 327.4. C and boiling point is 17250 C. Uses: lead is used in paints, batteries, cable covers, plumbing devices, and toys. The most stable form of lead is its hydroxyl form. Health effects: lead disturbs the physiological processes. The symptom of lead toxicity includes abdominal pain, systems involving nervous system, sleeplessness, restlessness and memory deterioration. Lead lowers the IQ levels in children. Mechanism of lead toxicity: lead being bivalent metal replaces the other bivalent essential metals of the living system such as Ca, Mg, Fe. The ionic mechanism of toxicity brings along many changes in the body, such as cell adhesion, protein folding. Lead substitute’s calcium in the biological systems [85]. Sources of lead toxicity: There are various sources of lead toxicity in the environment, out of which major contributors are the paint industries and the

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Fig. 4 Biogeochemical cycling of Mercury [84]

petrochemical industries (Fig. 5). These contribute to approx. 98% of the lead toxicity [86]. 10.1.4

Arsenic

Arsenic is the 33 element in the periodic table. It occurs with various oxidation states such as (−III), (0), (III), and (V). The high toxicity of arsenic is also because its traces are fund in the groundwater as easily enters the natural geologic processes [87]. i. ii. iii. iv.

v.

Arsenic is a carcinogenic metal. Sources: the main sources are industrial wastes which are left unattended, pesticides, production of energy from fossils. Occurrence: it occurs naturally in the groundwater, rock, and soil. Fish are sources of organic arsenic. Health effects: Arsenic is linked with gastrointestinal symptoms, cardiovascular problems. People exposed to arsenic through drinking water are more prone to skin problems, cancer and kidney related disorders. The WHO has concluded that arsenic exposure via drinking water is related to kidney, lungs, and skin cancer respectively. Mechanism of arsenic toxicity: The arsenic compound gets transformed to monomethylarsonic acid (MMA) by some bacteria and fungi. MMA is a

Application of Green Synthesis of Nanoparticles … Fig. 5 Sources of Lead in environment [85]

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SOURCES OF LEAD IN ENVIRONMENT

Factory chimneys

Exhaust of automobiles

Urban soil Wast

ferlizer and pescides

metal plang and finishing

Melng and smelng of ores

Effluent from storage baery

addives in gasoline

toxic product and is not excreted out and responsible for carcinogenesis. The mechanism of toxicity is depicted in the Fig. 6. [88] (Table 3).

11 Conclusion Heavy metals are naturally occurring metals which have densities 55 times more than the water. The heavy metals could not be degraded. Their wide use in the industries has increased their amount in the environment posing a threat to the living system. The distribution has been changed, and it is threatful for the living system as these metals keep on accumulating in the food chain, i.e. bioaccumulation. Heavy metals enter the living system through industrial effluents dumped in the water. Using green chemistry to replace the synthetic polymer base materials for recovering heavy metal is an environmental friendly approach. It focuses on maximizing the use of biopolymers in industrial, medical application, and economic concerns. There are various physical and chemical methods in use for removal of heavy metals such as electro coagulation, adsorption, precipitation, flocculation, etc.

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Chromosomal abnormalies

Inacvaon of transcripon factors Mechanism of arsenic toxicity

11

Binding with metalloprotein

Inhibion of enzyme acvity

Fig. 6 Mechanism of Arsenic toxicity Table 3 Heavy metal in water and their toxic effects on health [34]

Metal

Toxic effect

Lead

• • • •

Nickel

• DNA damage • Eczema on hands

Chromium

• Irritation of gastrointestinal mucosa • Necrosis

Copper

• Mucosal irritation • Depression

Cadmium

• Damage kidney and brain • Bronchitis • Anaemia

Mercury

• Disturbs cholesterol • Mutagenic effects

Arsenic

• Toxicological and carcinogenic effects • Immunotoxic • Genotoxic

High dose causes metabolic poison Tiredness Irritability Hypertension

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The heavy metal exposure also occurs through the pipes used; alum used in water treatment increases Aluminum content in water. c. Furthermore, the nanoparticles and Nanosorbent have high advantages for the separation of heavy metal ions.

12 Recommendation The various effects of heavy metals in environment and their treatment methods have been listed out here. However there remain certain issues which remain unresolved and demands further investigation are listed out as follows: i. ii.

iii.

The adsorbent’s surface must be activated beforehand by a chemical or physical process to increase the adsorption capacity. Analysis of reports from results of various studies should be carried out unmistakably among different mechanisms available for removal of heavy metals. The ion exchange resins should be frequently regenerated. However the regeneration causes environmental pollution. Steps should be taken to minimize the secondary pollution in environment.

References 1. Jin, S., Park, B. C., Ham, W. S., Pan, L., & Kim, Y. K. (2017). Effect of the magnetic core size of amino-functionalized Fe3O4-mesoporous SiO2 core-shell nanoparticles on the removal of heavy metal ions. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 531, 133–140. https://doi.org/10.1016/j.colsurfa.2017.07.086 2. Sabiha, J., Mehmood, T., Chaudhry, M. M., Tufail, M., & Irfan, N. (2009). Heavy metal pollution from phosphate rock used for the production of fertilizer in Pakistan. Microchemical Journal, 91(1), 94–99. https://doi.org/10.1016/j.microc.2008.08.009 3. Wang, J., & Chen, C. (2009). Biosorbents for heavy metals removal and their future. Biotechnology Advances, 27(2), 195–226. https://doi.org/10.1016/j.biotechadv.2008.11.002 4. Malik, N., Biswas, A. K., Qureshi, T. A., Borana, K., & Virha, R. (2009). Bioaccumulation of heavy metals in fish tissues of a freshwater lake of Bhopal. Environmental Monitoring and Assessment, 160(1), 267. https://doi.org/10.1007/s10661-008-0693-8 5. Das, S., Raj, R., Mangwani, N., Dash, H. R., & Chakraborty, J. (2014) 2—Heavy metals and hydrocarbons: adverse effects and mechanism of toxicity. In: S. Das (ed.), Microbial biodegradation and bioremediation (pp 23–54). Elsevier, Oxford. https://doi.org/10.1016/B978-0-12800021-2.00002-9 6. Bashir, A., Malik, L. A., Ahad, S., Manzoor, T., Bhat, M. A., Dar, G. N., & Pandith, A. H. (2019). Removal of heavy metal ions from aqueous system by ion-exchange and biosorption methods. Environmental Chemistry Letters, 17(2), 729–754. https://doi.org/10.1007/s10311018-00828-y 7. De Young, R. (1986). Some psychological aspects of recycling: The structure of conservation— satisfactions. Environment and Behavior, 18(4), 435–449. https://doi.org/10.1177/001391658 6184001

84

S. Singh et al.

8. Alloway BJ (2013) Sources of heavy metals and metalloids in soils. In Heavy metals in soils (pp 11–50). Springer. 9. Clarke, R. (2013). Water: The international crisis. Routledge. 10. Förstner, U., & Wittmann, G. T. (2012). Metal pollution in the aquatic environment. Springer Science & Business Media. 11. Walters, V., & Gaillard, J. (2014). Disaster risk at the margins: Homelessness, vulnerability and hazards. Habitat International, 44, 211–219. 12. Salaam-Blyther, T. (2012). Global access to clean drinking water and sanitation: US and international programs. Report R42717. Congressional Research Service. 13. Vestbo, J., Hurd, S. S., Agustí, A. G., Jones, P. W., Vogelmeier, C., Anzueto, A., Barnes, P. J., Fabbri, L. M., Martinez, F. J., & Nishimura, M. (2013). Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease: GOLD executive summary. American Journal of Respiratory and Critical Care Medicine, 187(4), 347–365. 14. Vogelmeier, C. F., Criner, G. J., Martinez, F. J., Anzueto, A., Barnes, P. J., Bourbeau, J., Celli, B. R., Chen, R., Decramer, M., & Fabbri, L. M. (2017). Global strategy for the diagnosis, management, and prevention of chronic obstructive lung disease 2017 report. GOLD executive summary. American Journal of Respiratory and Critical Care Medicine, 195(5), 557–582. 15. Saha, R., Nandi, R., & Saha, B. (2011). Sources and toxicity of hexavalent chromium. Journal of Coordination Chemistry, 64(10), 1782–1806. 16. Kurzweil, P. (2010). Gaston Planté and his invention of the lead–acid battery—The genesis of the first practical rechargeable battery. Journal of Power Sources, 195(14), 4424–4434. https:// doi.org/10.1016/j.jpowsour.2009.12.126 17. Nagajyoti, P., Lee, K., & Sreekanth, T. (2010). Heavy metals, occurrence and toxicity for plants: A review. Environmental Chemistry Letters, 8(3), 199–216. 18. Gillis, B. S., Arbieva, Z., & Gavin, I. M. (2012). Analysis of lead toxicity in human cells. BMC Genomics, 13(1), 344. 19. Shannon, M. A., Bohn, P. W., Elimelech, M., Georgiadis, J. G., Mariñas, B. J., & Mayes, A. M. (2010). Science and technology for water purification in the coming decades. Nanoscience and Technology, 337–346. https://doi.org/10.1142/9789814287005_0035 20. Abbasi, T., & Abbasi, S. A. (2012). Water quality indices. Elsevier. 21. Kelly-Vargas, K., Cerro-Lopez, M., Reyna-Tellez, S., Bandala, E. R., & Sanchez-Salas, J. L. (2012). Biosorption of heavy metals in polluted water, using different waste fruit cortex. Physics and Chemistry of the Earth, Parts A/B/C, 37–39, 26–29. https://doi.org/10.1016/j.pce. 2011.03.006 22. Fatta-Kassinos, D., Kalavrouziotis, I. K., Koukoulakis, P. H., & Vasquez, M. I. (2011). The risks associated with wastewater reuse and xenobiotics in the agroecological environment. Science of The Total Environment, 409(19), 3555–3563. https://doi.org/10.1016/j.scitotenv.2010.03.036 23. Pérez-López, R., Castillo, J., Quispe, D., & Nieto, J. M. (2010). Neutralization of acid mine drainage using the final product from CO2 emissions capture with alkaline paper mill waste. Journal of Hazardous Materials, 177(1), 762–772. https://doi.org/10.1016/j.jhazmat.2009. 12.097 24. Tchounwou, P. B., Yedjou, C. G., Patlolla, A. K., Sutton, D. J. (2012). Heavy metal toxicity and the environment. In Molecular, clinical and environmental toxicology (pp. 133–164), Springer 25. Matés, J. M., Segura, J. A., Alonso, F. J., & Márquez, J. (2010). Roles of dioxins and heavy metals in cancer and neurological diseases using ROS-mediated mechanisms. Free Radical Biology and Medicine, 49(9), 1328–1341. 26. Lim, S.-R., Kang, D., Ogunseitan, O. A., & Schoenung, J. M. (2010). Potential environmental impacts of light-emitting diodes (LEDs): Metallic resources, toxicity, and hazardous waste classification. Environmental Science and Technology, 45(1), 320–327. 27. Vörösmarty, C. J., McIntyre, P. B., Gessner, M. O., Dudgeon, D., Prusevich, A., Green, P., Glidden, S., Bunn, S. E., Sullivan, C. A., & Liermann, C. R. (2010). Global threats to human water security and river biodiversity. Nature, 467(7315), 555. 28. Ahmed, S., Ahmad, M., Swami, B. L., & Ikram, S. (2016). A review on plants extract mediated synthesis of silver nanoparticles for antimicrobial applications: A green expertise. Journal of Advanced Research, 7(1), 17–28. https://doi.org/10.1016/j.jare.2015.02.007

Application of Green Synthesis of Nanoparticles …

85

29. Makarov, V., Love, A., Sinitsyna, O., Makarova, S., Yaminsky, I., Taliansky, M., & Kalinina, N. (2014). “Green” nanotechnologies: synthesis of metal nanoparticles using plants. Acta Naturae (anglozyqna vepci), 6(1 (20)) 30. Saxena, A., Tripathi, R., Zafar, F., & Singh, P. (2012). Green synthesis of silver nanoparticles using aqueous solution of Ficus benghalensis leaf extract and characterization of their antibacterial activity. Materials Letters, 67(1), 91–94. 31. Wuana, R. A., & Okieimen, F. E. (2011). Heavy metals in contaminated soils: A review of sources, chemistry, risks and best available strategies for remediation. Isrn Ecology 32. Rascio, N., & Navari-Izzo, F. (2011). Heavy metal hyperaccumulating plants: how and why do they do it? And what makes them so interesting? Plant Science, 180(2), 169–181. 33. Fu, F., & Wang, Q. (2011). Removal of heavy metal ions from wastewaters: A review. Journal of Environmental Management, 92(3), 407–418. 34. Barakat, M. (2011). New trends in removing heavy metals from industrial wastewater. Arabian Journal of Chemistry, 4(4), 361–377. 35. Ge, H., Zhang, L., Batstone, D. J., Keller, J., & Yuan, Z. (2012). Impact of iron salt dosage to sewers on downstream anaerobic sludge digesters: Sulfide control and methane production. Journal of Environmental Engineering, 139(4), 594–601. 36. Rivest, J. B., & Jain, P. K. (2013). Cation exchange on the nanoscale: An emerging technique for new material synthesis, device fabrication, and chemical sensing. Chemical Society Reviews, 42(1), 89–96. 37. Faust, S. D., & Aly, O. M. (2013). Adsorption processes for water treatment. Elsevier. 38. Prabhu, P. P., & Prabhu, B. (2018). A review on removal of heavy metal ions from waste water using natural/ modified bentonite. MATEC Web Conference, 144, 02021. 39. Worch, E. (2012). Adsorption technology in water treatment: Fundamentals, processes, and modeling. Walter de Gruyter. 40. Almomani, F., Bhosale, R., Khraisheh, M., kumar, A., & Almomani, T. (2020). Heavy metal ions removal from industrial wastewater using magnetic nanoparticles (MNP). Applied Surface Science 506, 144924. https://doi.org/10.1016/j.apsusc.2019.144924. 41. Bhatnagar, A., Hogland, W., Marques, M., & Sillanpää, M. (2013). An overview of the modification methods of activated carbon for its water treatment applications. Chemical Engineering Journal, 219, 499–511. 42. Fiyadh, S. S., AlSaadi, M. A., Jaafar, W. Z., AlOmar, M. K., Fayaed, S. S., Mohd, N. S., Hin, L. S., & El-Shafie, A. (2019). Review on heavy metal adsorption processes by carbon nanotubes. Journal of Cleaner Production 230, 783–793. https://doi.org/10.1016/j.jclepro.2019.05.154. 43. Ngah, W. W., Teong, L., & Hanafiah, M. (2011). Adsorption of dyes and heavy metal ions by chitosan composites: A review. Carbohydrate Polymers, 83(4), 1446–1456. 44. Sulekha, M. (2016). Nano technology and waste water treatment: opportunities and challenges. International Journal of Research, 3(5), 104–108. 45. Das, R., Ali, M. E., Hamid, S. B. A., Ramakrishna, S., & Chowdhury, Z. Z. (2014). Carbon nanotube membranes for water purification: A bright future in water desalination. Desalination, 336, 97–109. 46. Shannon, M. A., Bohn, P. W., Elimelech, M., Georgiadis, J. G., Marinas, B. J., & Mayes, A. M. (2010). Science and technology for water purification in the coming decades. In Nanoscience and technology: a collection of reviews from nature journals (pp. 337–346) World Scientific. 47. Nasrollahzadeh, M., Sajadi, S. M., Sajjadi, M., & Issaabadi, Z. (2019). Chapter 1—an introduction to nanotechnology. In M. Nasrollahzadeh, S. M. Sajadi, M. Sajjadi, Z. Issaabadi, M. Atarod (eds.), Interface science and technology (Vol 28, pp. 1–27). Elsevier. https://doi.org/10. 1016/B978-0-12-813586-0.00001-8 48. Degtyarenko, D., Naumenko, D., & Ostreiko, S. (2016). What is Nanotechnology? 49. Rogers, B., Adams, J., & Pennathur, S. (2012). Nanotechnology: understanding small systems. Crc Press. 50. Aricò, A. S., Bruce, P., Scrosati, B., Tarascon, J.- M., & Schalkwijk, W. V. (2011) Nanostructured materials for advanced energy conversion and storage devices. In Materials for sustainable energy (pp. 148–159). https://doi.org/10.1142/9789814317665_0022

86

S. Singh et al.

51. Glezer, A. (2011). Structural classification of nanomaterials. Russian Metallurgy (Metally) (4), 263. 52. Habiba, K., Makarov, V. I., Weiner, B. R., & Morell, G. (2014). Fabrication of nanomaterials by pulsed laser synthesis. One Central Press, Manchester. 53. Krysak, M., Trikeriotis, M., Schwartz, E., Lafferty, N., Xie, P., Smith, B., Zimmerman, P., Montgomery, W., Giannelis, E., Ober, C. K. (2011) Development of an inorganic nanoparticle photoresist for EUV, e-beam, and 193nm lithography. In Advances in Resist Materials and Processing Technology XXVIII (p. 79721C). International Society for Optics and Photonics 54. Crane, R., & Scott, T. (2012). Nanoscale zero-valent iron: Future prospects for an emerging water treatment technology. Journal of Hazardous Materials, 211, 112–125. 55. Lei, W., Portehault, D., Liu, D., Qin, S., & Chen, Y. (2013). Porous boron nitride nanosheets for effective water cleaning. Nature Communications, 4, 1777. 56. Mostafa, S., Behafarid, F., Croy, J. R., Ono, L. K., Li, L., Yang, J. C., Frenkel, A. I., & Cuenya, B. R. (2010). Shape-dependent catalytic properties of Pt nanoparticles. Journal of the American Chemical Society, 132(44), 15714–15719. 57. Lowell, S., Shields, J. E., Thomas, M. A., Thommes, M. (2012). Characterization of porous solids and powders: surface area, pore size and density (vol 16). Springer Science & Business Media 58. Azizullah, A., Khattak, M. N. K., Richter, P., & Häder, D.-P. (2011). Water pollution in Pakistan and its impact on public health—A review. Environment International, 37(2), 479–497. 59. Kim, J., & Van der Bruggen, B. (2010). The use of nanoparticles in polymeric and ceramic membrane structures: Review of manufacturing procedures and performance improvement for water treatment. Environmental Pollution, 158(7), 2335–2349. https://doi.org/10.1016/j.env pol.2010.03.024 60. Zhang, S., Wu, Y., He, B., Luo, K., & Gu, Z. (2014). Biodegradable polymeric nanoparticles based on amphiphilic principle: Construction and application in drug delivery. Science China Chemistry, 57(4), 461–475. 61. Farooq, U., Kozinski, J. A., Khan, M. A., & Athar, M. (2010). Biosorption of heavy metal ions using wheat based biosorbents–A review of the recent literature. Bioresource Technology, 101(14), 5043–5053. 62. Xu, P., Zeng, G. M., Huang, D. L., Feng, C. L., Hu, S., Zhao, M. H., Lai, C., Wei, Z., Huang, C., & Xie, G. X. (2012). Use of iron oxide nanomaterials in wastewater treatment: A review. Science of the Total Environment, 424, 1–10. 63. Squadrone, S., Prearo, M., Brizio, P., Gavinelli, S., Pellegrino, M., Scanzio, T., Guarise, S., Benedetto, A., & Abete, M. (2013). Heavy metals distribution in muscle, liver, kidney and gill of European catfish (Silurus glanis) from Italian Rivers. Chemosphere, 90(2), 358–365. 64. Ghosh, A. K., Bhatt, M. A., & Agrawal, H. (2012). Effect of long-term application of treated sewage water on heavy metal accumulation in vegetables grown in Northern India. Environmental Monitoring and Assessment, 184(2), 1025–1036. 65. Momodu, M., & Anyakora, C. (2010). Heavy metal contamination of ground water: The surulere case study. Research Journal of Environmental and Earth Sciences, 2(1), 39–43. 66. Brewer, G. J. (2010). Copper toxicity in the general population. Clinical Neurophysiology, 121(4), 459–460. 67. Hessel, C. M., Pattani, V. P., Rasch, M., Panthani, M. G., Koo, B., Tunnell, J. W., & Korgel, B. A. (2011). Copper selenide nanocrystals for photothermal therapy. Nano Letters, 11(6), 2560–2566. 68. Akbal, F., & Camcı, S. (2011). Copper, chromium and nickel removal from metal plating wastewater by electrocoagulation. Desalination, 269(1–3), 214–222. 69. Ghassemieh, E. (2011). Materials in automotive application, state of the art and prospects. In New trends and developments in automotive industry. InTech. 70. Tchomgui-Kamga, E., Alonzo, V., Nanseu-Njiki, C. P., Audebrand, N., Ngameni, E., & Darchen, A. (2010). Preparation and characterization of charcoals that contain dispersed aluminum oxide as adsorbents for removal of fluoride from drinking water. Carbon 48(2), 333–343

Application of Green Synthesis of Nanoparticles …

87

71. Srinivasan, P., Viraraghavan, T., & Subramanian, K. (1999). Aluminium in drinking water: An overview. Water Sa, 25(1), 47–55. 72. McElroy, A. (2018). Medical anthropology in ecological perspective. Routledge. 73. Vikrant, K., Kumar, V., Vellingiri, K., & Kim, K.-H. (2019). Nanomaterials for the abatement of cadmium (II) ions from water/wastewater. Nano Research, 12(7), 1489–1507. 74. Genchi, G., Sinicropi, M. S., Lauria, G., Carocci, A., & Catalano, A. (2020). The effects of cadmium toxicity. International Journal of Environmental Research and Public Health, 17(11), 3782. 75. Butler, E., Hung, Y.-T., Yeh, R.Y.-L., & Suleiman Al Ahmad, M. (2011). Electrocoagulation in wastewater treatment. Water, 3(2), 495–525. 76. Osredkar, J., & Sustar, N. (2011). Copper and zinc, biological role and significance of copper/zinc imbalance. Journal of Clinical Toxicology S, 3, 2161–2495. 77. Noulas, C., Tziouvalekas, M., & Karyotis, T. (2018). Zinc in soils, water and food crops. Journal of Trace Elements in Medicine and Biology, 49, 252–260. 78. Rajoriya, S., & Kaur, B. (2014). Adsorptive removal of zinc from waste water by natural biosorbents. The International Journal of Science and Engineering Investigations, 3, 60–80. 79. Gunatilake, S. (2015). Methods of removing heavy metals from industrial wastewater. Methods, 1(1) 80. Haileslassie, T., & Gebremedhin, K. (2015). Hazards of heavy metal contamination in ground water. International Journal of Technology Enhancements and Emerging Engineering Research, 3(2), 1–6. 81. Abel, P. D. (2014). Water pollution biology. CRC Press. 82. Bernhoft, R. A. (2013). Cadmium toxicity and treatment. The Scientific World Journal. 83. Mozaffarian, D., Shi, P., Morris, J. S., Spiegelman, D., Grandjean, P., Siscovick, D. S., Willett, W. C., & Rimm, E. B. (2011). Mercury exposure and risk of cardiovascular disease in two US cohorts. New England Journal of Medicine, 364(12), 1116–1125. 84. Azevedo, R., & Rodriguez, E. (2012). Phytotoxicity of mercury in plants: a review. Journal of Botany. 85. Flora, G., Gupta, D., & Tiwari, A. (2012). Toxicity of lead: A review with recent updates. Interdisciplinary Toxicology, 5(2), 47–58. 86. Meena, V, Dotaniya, M. L., Saha, J. K., Das, H., & Patra, A. K. (2020). Impact of lead contamination on agroecosystem and human health. In Lead in plants and the environment. (pp. 67–82). Springer. 87. Ahsan, D., & Del Valls, T. (2011). Impact of arsenic contaminated irrigation water in food chain: An overview from Bangladesh. International Journal of Environmental Research, 5(3), 627–638. 88. Singh, A. P., Goel, R. K., & Kaur, T. (2011). Mechanisms pertaining to arsenic toxicity. Toxicology International, 18(2), 87.

Waste Management in Indian Pharmaceutical Industries Shivangi Upadhyay and Alok Sinha

Abstract In recent years, the Indian pharmaceutical industry has gradually evolved witnessing a major development in this sector. India has become the third largest API (Active pharmaceutical ingredient) merchant and is likely to be among the top three pharmaceutical markets by 2020. Though this will strengthen the economic growth of the country but subsequently it is fuelling the major environmental crisis such as waste generation. The unwanted materials produced at the time of manufacturing can turn out to be hazardous to the environment. Like the ash produced from the boiler furnace, impurities from the extraction unit and chemical waste from the processing unit. Today waste management practices become an integrated approach of waste reduction and recycling in order to enhance sustainable development. Common management practices employed by the pharmaceutical industries in India are Incineration, autoclaving, coagulation, constructed wetlands, and vermicomposting. Also, owing to the lack of proper disposal technique, some manufacturing industries often sell the hazardous/solid waste to the authorized re-processor or end user. This chapter elucidates the possible route of waste generation from pharmaceutical industries. It also shed some light on the current waste management technique used in India and also defines its shortcoming and limitations.

1 Introduction The unwanted and unusable materials that people no longer use and are intended for discard purpose are termed as waste. These wastes are hazardous to the environment as well as for human health if not discarded immediately [1]. Different forms of wastes originate from various sources like industry (e.g., pharmaceutical companies, clothes manufacturers, etc.), households, agriculture (e.g., slurry), mining and quarrying activities, commercial activities (e.g., shops, restaurants, hospitals, etc.), and S. Upadhyay · A. Sinha (B) Department of Environmental Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad 826004, Jharkhand, India e-mail: [email protected] © Springer Nature Switzerland AG 2022 S. Yadav et al. (eds.), Environmental Management in India: Waste to Wealth, https://doi.org/10.1007/978-3-030-93897-0_5

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construction and demolition projects. Among these different types of wastes, pharmaceuticals wastes are also of different types, i.e., hazardous, and non-hazardous waste [2]. The pharmaceutical industry is based primarily upon scientific research and development (R&D) of medicines that treat or prevent disorders and diseases. Drugs formed due to pharmaceutical activity exhibit a broad range of toxicological properties [3–7]. The waste contains active ingredients along with excipients that affect the environment and thus deteriorating public health [8, 9]. Pharmaceutical industries generate huge amount of waste irrespective of their size of business. The pharmaceutical industries use many chemical and biological agents to generate different types of drugs. The Indian pharmaceutical sector accounts for 3.1–3.6%* of the global pharmaceutical industries in10 per cent in volume terms and value terms. It is estimated that it will reach US$100 billion by 2025. The global exports in generics for India accounts for 20%. The pharmaceutical exports of India were at US$ 16.84 billion in 2016–2017 and expected to reach US$ 20 billion by 2020 [10]. During April–September 2017, the export of Indian pharmaceutical products was worth Rs. 411.3 billion (US$ 6.4 billion) and During April–October 2017, the export of pharmaceutical products was worth Rs. 478.3 billion (US$ 7.4 billion) which is increasing. The manufacturing process of some pharmaceutical industries are similar to biochemical, and synthetic organic chemical industries but the specific applications in the pharmaceutical industry are unique. The manufacturing process in these industries includes extraction, processing, purification, and packaging of chemical materials to be finally used as medications for humans or animals in order to prevent diseases and disorders. The manufacturing process is mainly divided into two major steps: First is the primary production i.e. production of the active ingredient or drug and the second step is the conversion of the active drug produced from primary processing into products suitable for consumption or use. The desired pharmaceutical product depends upon the raw material used in the manufacturing process. The waste generation from pharmaceutical industries differs in quantity as well as quality. The liquid pharmaceutical wastes may be divided into the following categories: • Wash waters used for cleaning of the floors and equipment, • Spent liquor of the fermentation process, • Wasted containing acids, bases, and solvents used for extraction and purification of the product The pharmaceutical industries releases harmful contaminants which entered into the environment through various routes like the discharge of wastewater, sewer lines, runoff, seepage from landfill sites, etc. During pharmaceutical manufacturing and maintenance operations, a huge quantity of waste is generated and traces of these wastes have been found in drinking water sources and if present for longer period then causing serious health effects to be aquatic as well as human life [11]. The waste generation may vary in composition, magnitude depending upon industry type and seasonal variation. Due to the adverse impact of synthetic chemicals on the environment as well as human health, the oldest medical care system in India, herbal pharma and cosmetic industries are getting more attention [12]. The cure for many health

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diseases and disorders by use of herbal method have been mentioned in the Vedas. Herbal pharma industries are now days generating a huge market which is estimated to be about one billion dollars (US). The processing unit of these industries generate a huge quantity of spent wastes after manufacturing of the drug, and this creates a serious environmental problem. The waste generated from these industries are not properly treated before dumping or discharging, rather they are left openly at open space nearby industrial area or landfill sites. The major disadvantages behind openly left over waste at dumping sites lead to emission of greenhouse gases, nitrate leaching to groundwater, nutrient enrichments in surface water bodies and prolification and breeding of disease vectors [13]. The disposal of these wastes after the stabilization process may solve the environmental problems [14]. The concern has been increasing towards the use of the generated wastes as a resource for energy production and land restoration. For the management of solid waste, recycling, reuse and recovery is the best option. Presence of diversity of decomposers or detritus feeders (fungi, actinomycetes, protozoa, nematodes, annelids, arthropods, etc.) decomposes the complex organic substances of wastes. In this regard, one of the emerging and interesting alternatives to convert waste into less toxic form is vermicomposting [15]. In this process, earthworms and microorganisms work together for the stabilization of organic material. Earthworms are important in conditioning the substrate while microorganisms are used for biochemical degradation of organic matter [16].

2 Evolution of Indian Pharmaceutical Sector During the 1970s to till now, the Pharma sector of India has evolved in many ways. Indian patent act was passed in 1970, which led to opening up of several domestic companies, product infrastructure developed, and export initiatives were taken. A time period of 1990–2010, India became a major destination for generic drug manufacturing. The national pharmaceutical pricing policy was formulated. During 2010– 2015, manufacturing units in India are 10,500 and over 3000 pharma companies. From 2015 onwards, Government of India has ‘Pharma vision 2020’ and making India a global leader in end to end drug manufacturer. The structure of the Indian pharmaceutical sector is shown in Fig. 1

3 Treatment Methods 3.1 Incineration A disposal method in which ignition of solid waste organic matter is carried out to change them into residue and gaseous products. The volumes of solid waste get reduced to 20 to 30 percent of the original volume. Incineration and other

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Fig. 1 Structure of the Indian pharmaceutical sector

high-temperature waste treatment systems are sometimes described as “thermal treatment”. The method is useful for disposal of solid residue from wastewater management and residue of both solid waste management.

3.2 Autoclaving A high-temperature treatment method in a pressure vessel at time lengths to kill pathogens, to degrade noxious chemicals and microbes that grow on them is autoclaving. The residues of antibiotics often bear high organic loadings that can be treated using autoclaves.

3.3 Physicochemical Methods These include activated carbon, membrane separation, chlorination, chemical removal, ion exchange, coagulation-flocculation, precipitation, adsorption, electrochemical processes [17] and other novel approaches or combination of these methods. The efficiency of these methods differs significantly. Processes like precipitation-air floatation show a higher COD removal efficiency over coagulation–precipitation process, the latter involves less operating costs (almost 25%) than the former. The diversity in nature of the pharmaceuticals makes them treatment-specific for instance; for ex: an investigation of the principal removal mechanisms of Fluoroquinolone suggested adsorption of sludge and/or flocks is more effective than biodegradation [18, 19].

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3.4 Adsorption Process Adsorbents like zeolite have been successful in the treatment of compounds like Metformine and Lincomycine that are poorly treated by conventional activated carbon method. Additionally, the use of nanoparticles and magnetic particles have been gaining attention these years. Nanoparticles, nanotubes and allied components as adsorbents have a high surface area, resistance to materials and high tensile strength, counter to high chemical leaching tendency, pH sensitivity and other obstacles make them effective adsorbents for pharmaceuticals wastes [20–23].

3.5 Coagulation and Precipitation An effective pre-treatment step, coagulation and precipitation, increases the biodegradability of wastewater through the removal of oil and grease, suspended particulate matter, as well as specific compounds. Through coagulation colloidal particles are destabilized by promoting collisions between neutralized particles, resulting in cohesion and charge neutralization. The decrease in COD has been observed while using coagulants while also stabilizing some of the leaching prone components. However, the coagulation-precipitation process can only be applied in reducing load to the downstream secondary treatment unit only [24–26].

3.6 Electro-Coagulation Speeding up of conventional coagulation process by the addition of electric current is electro-coagulation which is characterized by hydroxide ions formation providing a large surface area for adsorption of colloidal particles and organic compounds. A study conducted by [27] to the treatment of real pharmaceutical wastewater by electro-coagulation decreased the COD loadings by 72% as well as improved the BOD/COD ratio from 0.18 to 0.3. The result showed high output in a comparatively small time interval, energy saving nature, and overall biodegradability enhancement of the wastewater [28, 29].

3.7 Constructed Wetlands Pharmaceuticals waste are mixed with other sewage and municipal waste sewers. So, it is difficult to isolate and individually process them. Activated sludge and constructed wetland are some biological processes that deal with a composite mixture of wastes. Pharmaceutical waste removed from constructed wetlands are of different

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types such as vertical subsurface flow constructed wetlands (VSSFCWs), surface free water constructed wetlands (SF-CWs), into horizontal subsurface flow constructed wetlands (HSSF-CWs), and hybrid constructed wetlands (hybrid CWs). The H-SSF (Horizontal Sub Surface Flow System) constructed wetland shows removal of all therapeutic classes (from 1% for psychiatric drugs to 26% for antihypertensive) when setting up in a pilot plant equipped with Phragmites australis [30–33].

3.8 Biological Processes Activated sludge and analogous processes can be used to improve final effluent quality if the effluent is subjected to tertiary treatment. This process shows removal efficiencies against pharmaceuticals like 78% for chlortetracycline 68% for tetracycline, and 67% doxycycline [34]. However, the problem associated with this type of treatment facility is that biotransformation residues left out in the output requires further treatment. Although biological processes are widely acceptable and successful in industrial application there are some constrains that the presence of tough PhACs (Pharmaceuticals active compounds) in pharmaceutical wastewater make this system ineffective [35–37].

3.9 Membrane Separation Advance processes like membrane separation has been emerging and proved to be eco-friendly, small, flexible, compact, economically feasible, easy installment and maintenance [38, 39]. Having high separation potential to separate organic loading along with other persistent compounds, this technology proved to be an environmentfriendly having low maintenance activity. A membrane-integrated hybrid technology proves to treat consolidated form of pharma wastes and municipal sludge and has higher efficiency than the conventional process, great compactness, sludge retention, capability to withstand fluctuating pollution load and thus maintaining quality treatment. Some pilot plant study carried out by [40, 41] shows around 95% COD removal efficiency which makes it an option for treating medicinal wastes having high COD loading. Some modification in membrane technology like submerged membrane electro-bioreactor (SMEBR) and fungal reactor might remove left out waste in the plant. The innovative combination of integrated membrane bioreactors and TiO2 photocatalysis process proved to be efficient for drugs like carbamazepine from simulated pharmaceutical industrial effluent if the recycling ratio is maintained at 4:1 then it will 95% of carbamazepine [42–44].

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Disposal: Incineration and Landfilling

Incineration, landfilling, and open burning are the common practices adopted for disposal of pharmaceuticals waste. Incineration to open air led to pollution of air, and on the other hand landfilling also is neither a fruitful method to curb the noxious waste.

4 Management Practices in India Zero discharge approach is the best management strategy in the case of wastes. The main principle lies behind the minimized generation of wastes to make the process green. Although achieving zero discharge approach is very much difficult, but some green approaches can be adopted to in order to meet the standards. One of them is green pharmacy approach or green chemistry approach. In this particular approach, the entire life cycle of the product is monitored. Another approach in regard of this approach is using biotechnology in the production of biopharmaceuticals and use of biocatalyst like isolated microorganisms and enzymes for producing pharmaceutically valuable materials. They are not only environmentally friendly but also economically feasible over synthetic catalysts. An online survey was conducted by [45] about environmental practices applied in small and medium enterprise Indian pharmaceutical industries. The survey highlighted two main environmental management practices i.e. implementation of ISO 14001 and establishing a department. The environmental management system (EMS) typically follows after the adoption of environmental policy by an organization and the formation of a department or environment management may be a precursor to implementing an ISO 14001-” [45, 46]. Implementation of EMS serves as an important tool, despite a lack of transparency and regular reports [47, 48]. The results of the survey showed that mainly 5 practices were followed i.e. current good manufacturing (CGMP) practices (84.5%), measurement of pollution level and reporting at regular intervals (69%), training to all employees on environmental regulatory issues and technology (54.9%), identification of environmental issues involved in the process (53.5%), and incorporating solutions in the process for meetings environmental standards (50.7%). Firms with effective EMS can deal better with managing stakeholder dynamics and their environmental performance,—[45] (http://sibresearch.org/upl oads/2/7/9/9/2799227/riber_s15-165_205-224.pdf). A study conducted by [48] for evaluating the performance of management of hazardous waste and effluent treatment plant of a pharmaceutical industry at Ankleshwar, Gujarat. This industry is manufacturing ethumbutol hydrochloride, 7-ADCA, 7-ACCA, D & L Mandelic acid, 7-AVAC, 7-APCA, 7-Amino ester, cefpodoxime acid, (2S)-3-dimethylamino-1(3- methoxyphenyl)-2methylpropan-1one, BAL1026, cefadroxil, 7-Anca and R & D Pilot plant trial run products. The sustainable steps towards environmental management have been well taken by

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the industry by maintaining records of generation of effluent, effective consumption of energy, onsite-offsite emergency plan, and proper safety measures for the workers. The obtained byproducts are sodium chloride, MESO, dilute sulphuric acid, calcium sulfate, phenyl acetic acid solution, ammonium chloride solution„ aminobutol, sodium acetate, dilute acetic acid, recovered ammonium solution, recovered isobutyl chloride, ammonium bromide solution, potassium bromide, ethyl acetate, Paratoluenesulphonic acid solution, boric acid, TPPO, potassium chloride, recovered IPA, recovered n-propanol. ISO 14001: 2004 certification has been received by the industry for developing bulk drugs and bulk drugs intermediate. The wastewater treatment method varies characteristics of effluent, level of toxicity to be removed, type of environment to receive the effluent and level of effluent. The effluent treatment plant adopts various physico-chemical treatment method like screening, coagulation, flocculation and sedimentation and for BOD and COD removal, biological treatment is applied. Organic solid wastes are degraded by incineration, whereas inorganic solid waste is sent to Transport storage disposal facilities. The data collected from the industries meets the norms of SPCB. A study conducted by [12] to investigate the decomposition of herbal pharmaceuticals industrial waste from spent material disposing unit of The Himalaya Drug Company, Dehradun which is one of the leading herbal pharmaceutical product manufacturing or processing unit in India. The waste was of mixed type containing spent material after extraction/ distillation of herbs and unused part of the plant. The treatment of herbal pharmaceutical waste was carried out with earthworm Eisenia fetida under laboratory conditions along with cow dung as feed material for the earthworms. The result showed the potential of vermicomposting to manage herbal pharmaceutical solid waste. This work suggested that if proper technology is applied in the management of these waste, then it may provide a valuable source of nutrients for the sustainable land restoration programme. A study conducted in laboratory condition by [49] investigated the treatment of wastewater coming out of the pharma industry by biological method aided by Fenton oxidation. The experimental result showed the COD removal efficiency to be 98% and suggested that wastewater treatment plants may apply aerobic degradation followed by Fenton oxidation in sequencing batch reactors to achieve this efficiency. Another study conducted by [50] demonstrated that an up-flow anaerobic stage reactor (UASR) was used for the treatment of pharmaceutical waste containing Tylosin and Avilamycin antibiotics and around 95% of Tylosin was removed in anaerobic condition. An Fe2 O3 /SBA-15 nano-composite catalyst was used by [51] for assessing the treatment of wastewater coming from a pharmaceutical plant through a continuous heterogeneous catalytic wet peroxide oxidation (CWPO) process and the result showed the enhancement in biodegradability of the compound. Kulik et al. [52] performed treatment of three wastewater samples from a pharmaceutical plant formulating medical ointments at lab-scale by a Fenton- like system in combination with lime coagulation which not only enhanced the quality of pharmaceutical effluents with different chemical characteristics but also helped in maintaining the discharge limits of wastewater and thus improving its biodegradability.

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5 Conclusion The pharmaceutical industry is one of the key industries saving millions of life by manufacturing medicines, but on the other hand generating enormous amount of wastes whether solid or liquid imposes a detrimental impact on the quality of water as well as on the environment and human life. A list of treatment techniques has been used extensively in regard to this. In Indian pharmaceutical industries, environmental management facility has been well adopted with proper treatment of liquid waste in effluent treatment plant and management of solid waste through incineration and deep burial.

6 Recommendations There should be a proper run-collection and disposal facility for the pharmaceutical wastes. Wastes must be treated by physicochemical methods like electro-coagulation followed by biodegradation of the residual waste. Further, there should be proper environmental management facility adopted at industrial scale for treatment of such type of wastes.

References 1. Dora, K. N., Kumari, K., Srivatsava, M., & Dalai, N. (2020). A review on various techniques for municipality waste management and product development. Materials Today: Proceedings. 2. Schnapf, D. (1981). State Hazardous waste programs under the federal resource conservation and recovery act. Environmental Law, 12, 679. 3. Goodman, L. S. (1996). Goodman and Gilman’s the pharmacological basis of therapeutics (Vol. 1549). McGraw-Hill. 4. Reynolds, J. (1989). Sodium cromoglycate and related anti-allergic agents, the extra pharmacopoeia, 29th edn. 5. Fick, J., Söderström, H., Lindberg, R. H., Phan, C., Tysklind, M., & Larsson, D. J. (2009). Contamination of surface, ground, and drinking water from pharmaceutical production. Environmental Toxicology and Chemistry, 28(12), 2522–2527. 6. Baldigo, B. P., George, S. D., Phillips, P. J., Hemming, J. D., Denslow, N. D., & Kroll, K. J. (2015). Potential estrogenic effects of wastewaters on gene expression in Pimephales promelas and fish assemblages in streams of southeastern New York. Environmental Toxicology and Chemistry, 34(12), 2803–2815. 7. Berninger, J. P., LaLone, C. A., Villeneuve, D. L., & Ankley, G. T. (2016). Prioritization of pharmaceuticals for potential environmental hazard through leveraging a large-scale mammalian pharmacological dataset. Environmental Toxicology and Chemistry, 35(4), 1007–1020. 8. Wilkinson, J., Hooda, P. S., Barker, J., Barton, S., & Swinden, J. (2017). Occurrence, fate and transformation of emerging contaminants in water: An overarching review of the field. Environmental Pollution, 231, 954–970. 9. Khan, H. K., Rehman, M. Y. A., & Malik, R. N. (2020). Fate and toxicity of pharmaceuticals in water environment: An insight on their occurrence in South Asia. Journal of Environmental Management, 271, 111030.

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10. Bhangale, V. (2008). Pharma marketing in India: Opportunities, challenges and the way forward. Journal of Medical Marketing, 8(3), 205–210. 11. Patneedi, C. B., & Prasadu, K. D. (2015). Impact of pharmaceutical wastes on human life and environment. Rasayan Journal of Chemistry, 8(1), 67–70. 12. Singh, D., & Suthar, S. (2012). Vermicomposting of herbal pharmaceutical industry solid wastes. Ecological Engineering, 39, 1–6. 13. Suthar, S. (2011). Utilizing livestock waste solids as bioresource for socio-economic sustainability: A report from rural India. Reviews in Environmental Science and Biotechnology. https:// doi.org/10.1007/s1157-011-92240-0 14. Brandon, G. M., Lazcano, C., Lores, M., & Dominguez, J. (2011). Short-term stabilization of grape marc through earthworms. Journal of Hazardous Materials, 187, 291–295. 15. Hait, S., & Tare, V. (2011). Vermistabilization of primary sewage sludge. Bioresource Technology, 102, 2812–2820. 16. Dominguez, J., & Edwards, C. A. (2004) Vermicomposting organic wastes: A review. In S. H. S. Hanna, & W. Z. A. Milkhail (Eds.), Soil zoology for sustainable development in the 21st century. 17. Cheng, H., Xu, W., Liu, J., Wang, H., He, Y., & Chen, G. (2007). Pretreatment of wastewater from triazine manufacturing by coagulation, electrolysis, and internal microelectrolysis. The Journal of Hazardous Materials, 146, 385–392. 18. Zorita, S., Martensson, L., & Mathiasson, L. (2009). Occurrence and removal of pharmaceuticals in a municipal sewage treatment system in the south of Sweden. Science of the Total Environment, 407, 2760–3277. 19. Batt, A. L., Kim, S., & Aga, D. S. (2007). Comparison of the occurrence of antibiotics in four full-scale wastewater treatment plants with varying designs and operations. Chemosphere, 68, 428–435. 20. Ridder, D., Verberk, D. J., Amya, H. J. Q. J. C., VanDijk, G. L., & JC,. (2012). Zeolites for nitrosamine and pharmaceutical removal from demineralised and surface water: Mechanisms and efficacy. Separation and Purification Technology, 89, 71–77. 21. Ghauch, A., Tuqan, A., & Assi, H. A. (2009). Antibiotic removal from water: Elimination of amoxicillin and ampicillin by microscale and nanoscale iron particles. Environmental Pollution, 157, 1626–1635. 22. Grisales-Cifuentes, C. M., Galvis, E. A. S., Porras, J., Flórez, E., Torres-Palma, R. A., & Acelas, N. (2021). Kinetics, isotherms, effect of structure, and computational analysis during the removal of three representative pharmaceuticals from water by adsorption using a biochar obtained from oil palm fiber. Bioresource Technology, 124753. 23. Hounfodji, J. W., Kanhounnon, W. G., Kpotin, G., Atohoun, G. S., Lainé, J., Foucaud, Y., & Badawi, M. (2021). Molecular insights on the adsorption of some pharmaceutical residues from wastewater on kaolinite surfaces. Chemical Engineering Journal, 407, 127176. 24. Ashraf, M. I., Ateeb, M., Khan, M. H., Ahmed, N., & Mahmood, Q. (2016). Integrated treatment of pharmaceutical effluents by chemical coagulation and ozonation. Separation and Purification Technology, 158, 383–386. 25. Hassan, S. S., Abdel-Shafy, H. I., & Mansour, M. S. (2019). Removal of pharmaceutical compounds from urine via chemical coagulation by green synthesized ZnO-nanoparticles followed by microfiltration for safe reuse. Arabian Journal of Chemistry, 12(8), 4074–4083. 26. Kooijman, G., de Kreuk, M. K., Houtman, C., & van Lier, J. B. (2020). Perspectives of coagulation/flocculation for the removal of pharmaceuticals from domestic wastewater: A critical view at experimental procedures. Journal of Water Process Engineering, 34, 101161. 27. Pal, P., & Thakura, R. (2017). Pharmaceutical waste treatment and disposal of concentrated rejects: A review. International Journal of Engineering Technology Science and Research, 4(9), 2394–3386. 28. Zaidi, S., Chaabane, T., Sivasankar, V., Darchen, A., Maachi, R., & Msagati, T. A. M. (2019). Electro-coagulation coupled electro-flotation process: Feasible choice in doxycycline removal from pharmaceutical effluents. Arabian Journal of Chemistry, 12(8), 2798–2809.

Waste Management in Indian Pharmaceutical Industries

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29. Dinda¸s, G. B., Çalı¸skan, Y., Celebi, E. E., Tekba¸s, M., Bekta¸s, N., & Yatmaz, H. C. (2020). Treatment of pharmaceutical wastewater by combination of electrocoagulation, electro-fenton and photocatalytic oxidation processes. Journal of Environmental Chemical Engineering, 8(3), 103777. 30. Karthikeyan, K. G., & Meyer, M. T. (2006). Occurrence of antibiotics in wastewater treatment facilities in Wisconsin, USA. Science of the Total Environment, 361, 196–207. 31. Ávila, C., García-Galán, M. J., Uggetti, E., Montemurro, N., García-Vara, M., Pérez, S., & Postigo, C. (2021). Boosting pharmaceutical removal through aeration in constructed wetlands. Journal of Hazardous Materials, 125231. 32. Hu, B., Hu, S., Chen, Z., & Vymazal, J. (2020). Employ of arbuscular mycorrhizal fungi for pharmaceuticals ibuprofen and diclofenac removal in mesocosm-scale constructed wetlands. Journal of Hazardous Materials, 124524. 33. Delgado, N., Bermeo, L., Hoyos, D. A., Peñuela, G. A., Capparelli, A., Marino, D., & CasasZapata, J. C. (2020). Occurrence and removal of pharmaceutical and personal care products using subsurface horizontal flow constructed wetlands. Water Research, 187, 116448. 34. Buonomenna, M. G., & Bae, J. (2015). Organic Solvent Nanofiltration in Pharmaceutical Industry. Separation and Purification Reviews, 44(2), 157–182. 35. Serna-Galvis, E. A., Silva-Agredo, J., Botero-Coy, A. M., Moncayo-Lasso, A., Hernández, F., & Torres-Palma, R. A. (2019). Effective elimination of fifteen relevant pharmaceuticals in hospital wastewater from Colombia by combination of a biological system with a sonochemical process. Science of the Total Environment, 670, 623–632. 36. Wang, G., Wang, D., Xu, Y., Li, Z., & Huang, L. (2020). Study on optimization and performance of biological enhanced activated sludge process for pharmaceutical wastewater treatment. Science of The Total Environment, 739, 140166. 37. Ferrer-Polonio, E., Fernández-Navarro, J., Iborra-Clar, M. I., Alcaina-Miranda, M. I., & Mendoza-Roca, J. A. (2020). Removal of pharmaceutical compounds commonly-found in wastewater through a hybrid biological and adsorption process. Journal of Environmental Management, 263, 110368. 38. Chakrabortty, S., Pal, M., Roy, M., & Pal, P. (2015). Water treatment in a new flux-enhancing, continuous forward osmosis design: Transport modelling and economic evaluation towards scale up. Desalination, 365, 329–342. 39. Radjenovic, J., Petrovic, M., & Barcelo, D. (2009). Fate and distribution of pharmaceuticals in wastewater and sewage sludge of the conventional activated sludge (CAS) and advanced membrane bioreactor (MBR) treatment. Water Research, 43, 831–884. 40. Sipma, J., Osuna, B., Collado, N., Monclús, H., Ferrero, G., Comas, J., & Roda, I. R. (2010). Comparison of removal of pharmaceuticals in MBR and activated sludge systems. Desalination, 250, 653–659. 41. Homayoonfal, M., & Mehrnia, M. R. (2014). Amoxicillin separation from pharmaceutical solution by pH sensitive nanofiltration membranes. Separation and Purification Technology, 130, 74–83. 42. Basu, S., & Balakrishnan, M. (2017). Polyamide thin film composite membranes containing ZIF-8 for the separation of pharmaceutical compounds from aqueous streams. Separation and Purification Technology, 179, 118–125. 43. Chakrabortty, S., Nayak, J., Pal, P., Kumar, R., & Chakraborty, P. (2020). Separation of COD, sulphate and chloride from pharmaceutical wastewater using membrane integrated system: Transport modeling towards scale-up. Journal of Environmental Chemical Engineering, 8(5), 104275. 44. Balakrishnan, B. A., & Gurtoo, A. (2015). Environmental practices in the indian pharmaceutical SMEs: An assessment. Review of Integrative Business and Economics Research, 4(4), 205–224. 45. Campos-Castillo, C. (2012). Co-presence in virtual environments. Social Compass, 6(5), 425– 433. 46. Singh, M., Brueckner, M., & Padhy, P. K. (2014). Insights into the state of ISO 14001 certification in both small and medium enterprise and industry best companies in India: The case of Delhi and Noida. Journal of Cleaner Production, 69, 225–236.

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47. Sing, N. J., & Bagchi, S. (2013). Applied ecology in India: Scope of science and policy to meet contemporary environmental and socio-ecological challenges. Journal of Applied Ecology, 50, 4–14. 48. Brahmbhatt, N. C., & Pandya, K. Y. (2015). Performance evaluation of effluent treatment plant and hazardous waste management of pharmaceutical industry of Ankleshwar. Advances in Applied Science Research, 6(4), 157–161. 49. Tekin, H., Bilkay, O., Ataberk, S. S., Balta, T. H., Ceribasi, I. H., Sanin, F. D., Dilek, F. B., & Yetis, U. (2006). Use of Fenton oxidation to improve the biodegradability of a pharmaceutical wastewater. Journal of Hazardous Materials, 136(2), 258–265. 50. Chelliapan, S., Wilby, T., & Sallis, P. J. (2006). Performance of an up-flow anaerobic stage reactor (UASR) in the treatment of pharmaceutical wastewater containing macrolide antibiotics. Water Research, 40, 507–516. 51. Melero, J. A., Botas, J. A., Molina, R., Pariente, M. I., & Mart, F. (2009). Heterogeneous catalytic wet peroxide oxidation systems for the treatment of an industrial pharmaceutical wastewater. Water Research, 43(16), 4010–4018. 52. Kulik, N., Trapido, M., Goi, A., Veressinina, Y., & Munter, R. (2008). Combined chemical treatment of pharmaceutical effluents from medical ointment production. Chemosphere, 70(8), 1525–1531.

Erosion Management of Riparian Ecosystem in Coal Mining Area Through Selective Vegetation Nishant K. Srivastava and R. C. Tripathi

Abstract Open cast coal mining operations degrade the natural landscape and generate large quantity of mine refuse accumulated as over burden dump (OB dump), which is a serious environmental concern along with occupying the usable land area. Its proper restoration is required as a part of overall mining management plan. Taking into consideration, the R&D work was carried out aiming to identify and grow the efficient photosynthetic and soil conserver native plant species on selected OB dump in Eastern Jharia Coalfield (BCCL), Dhanbad. The selection of species is based on the ability to grow on the poor and dry mine soils, develop the vegetal cover in a short time, bind soil efficiently and improve the soil organic matter status. The mine refuse characteristics was determined before and after successive stages of the plantation together with growth performance of the planted species. After plantation of selected species, the physicochemical and biological parameters of mine soils were successively improved together with > 90% survival rate of the planted species. Among the species, i.e., Albizia lebbeck, Dalbergia sissoo and Acacia auriculaeformis (trees) and Vetiveria zizanioides and Cymbopogon flexuosus (herbs) were observed higher photosynthetic rate (8.9–26.5 µmol/m2 /sec) and soil conserving efficiency (62.0– 92.0%). SPM, SOx, NOx, and ambient CO2 concentrations were significantly (p < 0.05) reduced after selective plantation. The riparian habitat, an extremely fragile and delicately balanced ecosystem is severely degraded due to recurrent soil and water erosion leading to the deposition of silt in nearby water bodies. Herbaceous plant species on the riparian slopes play a major role in reducing the soil erosion, water runoff and nutrient loss. The role of some selected native riparian herbs dominant on the bank of nearby River Damodar was assessed in conserving the soil erosion and water loss. The soil and water conservation values (CV) of each of the species were computed. Among the vegetated plots, soil CV ranged from 30 to 85% and water CV from 20 to 48%. The losses through runoff water and eroded soil were found to be minimized from vegetated plots to a great extent as compared to the bare plots.

N. K. Srivastava (B) · R. C. Tripathi Industrial Biotechnology and Waste Management Research Group, CSIR-Central Institute of Mining & Fuel Research (Digwadih Campus), Dhanbad P.O. F.R.I.-828108,, Jharkhand, India © Springer Nature Switzerland AG 2022 S. Yadav et al. (eds.), Environmental Management in India: Waste to Wealth, https://doi.org/10.1007/978-3-030-93897-0_6

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Keywords Restoration · Amendment · Photosynthesis · Riparian herb · Soil loss · Conservation

1 Introduction The study was aimed to identify the efficient soil conserver plant species on the coal mine over burden and on the riparian ecosystem.

1.1 Coal Mining The coal mining activity degrades major areas of land and replace the existing ecosystem with undesirable waste materials (coaly matter/shale) which gets deposited on the surface in the form of overburden dumps [1, 2]. These dumps are poor in nutrient status including low soil organic matter, poor soil structure, poor drainage and low water holding capacity and devoid of biological activity [3–5]. The natural succession on these lands also takes longer duration, where micro-topographic and soil heterogeneity are important variables for mine reclamation[6, 7]. During surface mining, 2–11 times more land is damaged than the underground mining. The mining activities directly affect the landscape, loss of cultivated land, forest and pasture land and indirectly affect soil erosion, air and water pollution, toxicity, geo-environmental disasters, loss of biodiversity, and ultimately loss of economic wealth [8, 9]. Gaseous pollutants like CO2 , SOx, NOx, etc. are generated due to coal mining related operations and spontaneous combustion in coal stock and waste dumps [10]. As such in situ restoration is needed in respect of its ecological health through the development of suitable eco-friendly technology. The eco-restoration of mined-out land requires a permanent vegetation cover, which conserves the soil efficiently for longterm sustainable soil development [11]. The plant species including trees, herbs and shrubs can restore the soil fertility and improve the microclimatic conditions of the area [12–14]. The extensive and profound root system of tree species loosens the compacted soil to greater depth. It improves the mine soil through increase in soil organic matter, biological nitrogen fixation and uptake of nutrients, water infiltration and reduces nutrient loss, soil erosion and soil characteristics [15]. Some plant species accumulate more nutrients and may be more effective nutrient sinks than other species [16]. The successful and rapid establishment of indigenous vegetation on the coaly overburden, addition of some top soil is essential [17–20]. Indigenous species are preferable than the exotics because they are most likely to robust and well adaptable in a specific ecosystem because the exotic species are less common in areas with low anthropogenic disturbances [21, 22]. On mine-degraded land, nitrogen is a major limiting factor and addition of N fertilizer becomes a common practice to maintain healthy growth and persistence of vegetation [23]. An alternative approach is to introduce native legumes and other N2 -fixing species [24]. The ability of forests,

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trees and other vegetation as terrestrial carbon sinks to absorb CO2 emissions and mitigate climate change [25]. Thus the plantation of the efficient photosynthetic and soil conserver plant species is one of the alternatives to mitigate the CO2 and other air pollutants to an appreciable extent, where the role of selected plant species in mitigating these concerns of environmental health is currently of considerable importance. Coal fly ash being enriched with various nutrient (except nitrogen and humus) and having the capacity to improve the texture of soil due to its inherited high silt content (~60%), low bulk density and higher water holding capacity in combination with bio-fertilizer and other amendments can be well utilized for restoration of the mine over burden and its adjoining areas. Although few attempts have been made in the past to restore mine soil heaps through simple afforestation [26–28], these measures proved inadequate due to poor nutrient status, insufficient root binding capacity and lack of a proper selection of plant species that are adapted to prevailing biological conditions. From these considerations, the present study was carried out on the eco-restoration of mine over burden of Bharat Coking Coal Ltd, Dhanbad, Jharkhand through the plantation of efficient photosynthetic and soil conserver species. The role of common predominant species was determined in respect of improvement in mine refuse characteristics, soil and water conservation. The ambient air quality and physiological behaviour of the planted species have also been dealt.

1.2 Riparian Ecosystem Riparian ecosystems are relatively small areas that adjoin or directly influence the water body. They have two essential characteristics: laterally flowing water that rises and falls at least once within a growing season, and a high degree of connectedness with other ecosystems [29, 30]. The vegetation on the riparian areas stabilizes river banks; decrease the movement of soil and nutrients from upslope into the stream. Further, nutrient loss together with water runoff and soil erosion, leading to the impoverishment of riparian land, results in eutrophication of stream or river water. The vegetation on the riparian zones acts as a good harvester of nutrients from the catchment areas and control the eutrophication of the nearby water bodies [29]. The dense herbaceous vegetation on the slopes can reduce sediment runoff and provide important sources of organic matter and stabilize stream banks and create for different ecosystem services provided by river ecosystems [31]. In another study, Connolly et al. [32], Fierro et al. [33], Sun et al. [34] have advocated that riparian vegetation, besides performing as river embankment protection, it can promote ecological balance and biodiversity and increase the storage of nutrients and habitat for variety of wildlife. Dominika et al. [35] have indicated that riparian vegetation favours infiltration over surface runoff and maintain high moisture content in the area. There have been some attempts to restore the riparian ecosystem in an integrated way in few selected Indian wetlands [36–38]. Considering non-availability of any specific study relating to quantitative estimation of water runoff and soil erosion particularly

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of Damodar riparian ecosystem made till date, the study was carried out to determine the conservation potential of some of the dominated native riparian vegetation.

2 Materials and Methods To ecologically reclaim the coal mine over burden and determine the soil binding capacity of the selective plant species thereon on the one hand and to measure the soil and water conservation of riparian vegetation grown on sloppy land on the other hand, the below mentioned methodology was adopted.

2.1 Coal Mining Selection of site, preparation of mine refuse amendments and plantation In view of the prevailing industrial stresses due to different coal mining activities in Eastern Jharia (EJ) Coalfields, Bharat Coking Coal Ltd (BCCL) and dumping of mine refuse/over burden materials on cultivable/usable lands, approximately, 2.0 ha (10,000 m2 ) area of coal mine over burden dump (20 m height; 30% slope) was selected. The dump was properly levelled, compacted mechanically by JCB and manual as well and suitable steps were made based on the existing slope. Total 6500 pits (pit volume: 60 × 60 × 60 cm3 ) at a distance of 2 m were excavated and initially filled with pesticide (Phoretex @25 g/pit) to inhibit the soil-borne microorganisms/pathogens followed by good earth, fly ash and cow dung manure as amendments. The other amendments like coco peat, bio-fertilizer and NPK fertilizers were thoroughly mixed for maintaining the uniform fertility status of the excavated pits. The saplings of the selected native plant species such as Dalbergia sissoo, Albizia lebbeck, Delonix regia, Acacia auriculaeformis, Mangifera indica, Psidium gujava, Casuarina equisetifolia, Bougainvillea sp., Calistemon lanceolatus, Swietenia macrophylla, Thuja occidentalis, Ficus religiosa, F. benghalensis, Melia azedarch, Terminalia arjuna, Areca sp., among the tree species and Veteveria zizanioides, Cymbopogan flexuosus among the grasses having 1–2’ height, 1 year old, settled in poly bag (size: 5 × 7 ) in sturdy and disease free condition were planted. These species were identified based on their photosynthetic ability and soil conserving efficiency. The mine spoil samples were collected from the selected plantation site and analysed for different physicochemical and biological parameters before and after plantation. The planted saplings were under the regular supervision including watering (twice in a week), weeding and fertilizer application periodically. The list of different plant species planted at the selected site is shown in Table 1.

Erosion Management of Riparian Ecosystem in Coal Mining Area … Table 1 List of different plant species planted on mine soil

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S. No.

Botanical name

Local name

Family

1.

Albizia lebbeck

Kala Siris

Mimosaceae

2.

Dalbergia sissoo

Shisham

Papilionaceae

3.

Acacia auriculaeformis

Acacia

Mimosaceae

4.

Delonix regia

Gulmohar

Caesalpiniceae

5.

Ficus religiosa

Pipal

6.

Mangifera indica Aam

Anacardiaceae

7.

Psidium gujava

Amrud

Myrtaceae

8.

Melia sp.

Bakain

9.

Terminalia arjuna Arjun

Combretaceae

10.

Casuarina equisitifolia

Casuarinaceae

11.

Bougainvillea sp. Bogainvillea

Nyctaginaceae

12.

Callistemon lanceolatus

Bottle Brush

Myrtaceae

13.

Swietenia macrophyla

Mahogany

Meliaceae

14.

Thuja occidentalis

Thuja

Cupressaceae

15.

Areca sp.

Palm

Palmae

16.

Vetiveria zizanioides

Khus grass

Poaceae

17.

Cymbopogon flexuosus

Lemon grass

Poaceae

Casuarina

Moraceae

Meliaceae

Physicochemical and biological properties of mine refuse The physical properties viz. mechanical composition, bulk density (BD), porosity, water holding capacity (WHC) of mine refuse was determined using the methods, described in standard books [39, 40]. Chemical properties i.e. pH, electrical conductivity, organic carbon, available nutrients (N, P, K, S, Ca and Mg) was analyzed using the methods, described by Black [40–42]. For available trace and heavy metals content in mine spoil was determined by extracting the samples with diethylenetriamine pentaacetate (DTPA) using the prescribed method [41, 42]. The DTPAextractable fraction of available content in DTPA extracts of mine spoils was estimated by HPLC (Waters). The determination of Cu, Zn, Mn, Fe, Pb, Ni, Cd, and Co was made with a C18 column, with sodium octane sulphonate, tartaric acid, and acetonitrile as eluent; post column reagent; and ultraviolet light (UV) detector (520 nm). The standard sample for various trace and heavy elements was ICP multielement standard solution IV (Cat. No. 1.11355.0100; Merck). The detection limit for Cu, Co, Mn, and Zn, was 5 ppb; and for Cd, Cr, Fe, Ni, and Pb, 15 ppb.

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The estimation of VAM spores such as ecto and endomycorrhiza, P-solubilising and N-fixing bacteria in mine spoil was made using the methods as stated by Linderman [43], and the dehydrogenase activity by Klein et al. [44]. Physiological observation The rate of photosynthesis, transpiration and stomatal conductance was determined using the portable photosynthesis system (CI–310, CID Inc., USA). The portable photosynthesis system was factory calibrated but to ascertain better accuracy, the calibration of the equipment was made weekly. In built pressure sensor of the equipment measured absolute atmospheric pressure. This value was used in calibration for photosynthesis, transpiration and stomatal conductance. The instrument was capable of automatically controlling the flow rate of air from 0.1 to 0.99 l/min with the wavelength between 300 and 700 nm. Leaf area of the planted species was measured using Leaf Area Meter (CI–203, CID Inc, USA). It is equipped with a laser width scanner that is capable of measuring the width of an object resolution of 0.1 mm and is controlled by a microcomputer system that allows flexibility in configuring the instrument to make measurements accurately, easily and quickly. During the scanning mode, a rotating mirror causes a laser beam to scan across the object in its objectives 400 times a second. This beam is reflected off the special surface of the measuring arm and received by a light sensor inside the unit. Soil and water conservation The conservation value (CV) of each species for soil and water was calculated using the formula given by Ambasht [45]:   CV = 100 1 − Sp /So Where, Sp and So are the quantity of soil and water removed from vegetated and bare plots, respectively under identical erosive stresses. Air quality parameters The different air quality parameters like CO2 , suspended particulate matter (SPM) and gaseous pollutants like SOx and NOx in the samples collected through high volume air sampler were measured following the standard methods. Measurement of CO2 in ambient air was carried out using the Portable Photosynthesis System (CI310). The sampling and analysis of particulates were made as per Indian Standard Methods for measurement of air pollution; IS: 5182 (Part IV) [46]. The Whatman glass fibre filter paper was used for SPM and for RSPM Whatman EPM-2000 was used as the filtering medium. The measurement of SOx and NOx was made as per Indian Standard Methods for measurement of Air Pollution; IS: 5182 (Part II) [47] and IS: 5182 (Part VI) [48], respectively.

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Riparian land The dominant herbs [Leonotis nepetaefolia (L.) R. Br., Cassia tora L., Ageratum conyzoides L., Parthenium hysterophorus L., and Sida acuta burm f.,] were selected to determine their soil and water conservation values on the riparian slopes along Damodar river corridor in a culture experiment. The species were transplanted on five sloping experimental plots (25–30% slope) and the sixth plot was left bare. The area of each experimental plot was 4.7 m2 (2.61 × 1.8 m2 ). These plots were outlined with aluminium sheets (inserted in soil for about 6 cm and remaining 15 cm exposed in the air) from all sides to prevent water flow from the adjacent areas. At the lower end of sloping plots, cemented collection tanks were made to collect the runoff and eroded soil. The soil samples were collected from each of the experimental plots and characterized for textural (sand, silt, clay) and physicochemical parameters (BD, WHC, porosity, EC, pH, Organic-C, Total-N, P, K, S, Ca & Mg) using the prescribed methods [41]. At the time of planting, the density was kept uniform (121 individual plant m−2 ). The showering experiment was performed when the canopy was sufficient to cover the ground surface. Each plot was subjected to only one rain intensity throughout the experimentation. Artificial showering was made on vegetated and bare plots for 8.5 min using a multipore nozzle with 2 mm pore diameter from 1 m height at a constant intensity of 30 cm hr−1 [38]. The highsimulated rain intensity was selected to generate sufficient kinetic energy to cause adequate runoff in a short period. The experiment was carried out in triplicate and repeated at 10 days intervals in order to restore the plot characteristics after each treatment. The runoff volume from each plot was measured by rain gauge and the weight of soil by oven dry weight basis. Samples were taken immediately after each showering treatment to avoid evaporative losses; 0.45 µm pore size filter was used to separate water runoff and deposited soil. The soil samples were oven-dried at 80 °C for 36 h and passed through a 0.5 mm sieve for analysis. The canopy cover (%) of the vegetated plots was measured by the line transect method [49]. Standing crop biomass g m−2 was measured by harvest method and litter mass by oven dry weight basis. The antecedent moisture content of surface soil (0–10 cm) was measured by the oven dry weight basis before each rainfall treatment [41]. Statistical Analysis Stepwise multiple regression analysis was performed to estimate the degree of influence of factors like canopy cover, soil surface litter layer, standing crop biomass and the antecedent soil moisture content at the time of watering, individually as well as in combination[50].

3 Results and Discussion The results obtained both the mine refuse as well as from the riparian ecosystem were interpreted and discussed.

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3.1 Coal Mining (OB Dump) The findings of mine soil characteristics, ambient CO2 concentration, suspended particulate matter, gaseous pollutants and physiological parameters of planted species are discussed below:

3.1.1

Physicochemical and Biological Properties of Mine Refuse

Among the mechanical composition of the mine refuse (Table 2), the percentage of stone/shaly/gravely matter (>2 mm size) was 73.65% (before plantation), which was Table 2 Physicochemical characteristics of mine refuse before and after plantation Parameter

Before plantation

After plantation 1st yr

2nd yr

3rd yr

Mechanical > 2.0 mm size 73.65 ± 6.4 composition stone/shaly (%) matter)

70.86 ± 5.8

68.96 ± 4.7

64.46 ± 5.4

< 2.0 mm size 26.35 ± 2.1

33.54 ± 2.2

29.14 ± 2.3

30.11 ± 2.6

Bulk density (g cm−3 )

1.53 ± 0.06

1.49 ± 0.07

1.31 ± 0.04

1.23 ± 0.03

WHC (%)

15.70 ± 0.09

17.46 ± 0.08

22.58 ± 1.15

26.32 ± 1.35

Porosity (%)

53.69 ± 2.85

54.86 ± 2.65

58.12 ± 2.56

59.26 ± 2.62

EC (dS m−1 )

0.256 ± 0.005 0.245 ± 0.004 0.162 ± 0.002 0.157 ± 0.003

pH

7.79 ± 0.21

7.43 ± 0.23

6.87 ± 0.24

6.83 ± 0.28

Organic Carbon (%)

0.32 ± 0.002

0.41 ± 0.003

0.51 ± 0.002

0.53 ± 0.003

Available major and secondary nutrients (mg kg−1 ) N (%)

0.012 ± 0.001 0.017 ± 0.001 0.022 ± 0.002 0.034 ± 0.002

P

3.02 ± 0.02

4.27 ± 0.03

5.02 ± 0.03

5.23 ± 0.03

K

62.94 ± 4.2

68.39 ± 4.8

71.13 ± 5.2

73.05 ± 5.8

S

21.50 ± 1.7

26.20 ± 1.9

32.48 ± 2.1

33.84 ± 1.8

Ca

15.46 ± 1.2

16.12 ± 1.3

18.62 ± 1.5

20.48 ± 1.4

Mg

10.80 ± 0.76

13.72 ± 0.92

15.59 ± 0.75

16.95 ± 1.2

Micronutrients and trace/heavy metals (mg kg −1 ) Cu

1.90 ± 0.010

1.97 ± 0.014

2.08 ± 0.06

2.15 ± 0.015

Zn

1.36 ± 0.007

1.45 ± 0.009

1.58 ± 0.008

1.60 ± 0.01

Mn

5.45 ± 0.32

8.92 ± 0.48

10.25 ± 0.65

10.75 ± 0.72

Fe

17.36 ± 1.1

19.86 ± 1.3

21.95 ± 1.5

22.50 ± 1.5

Ni

1.93 ± 0.01

2.26 ± 0.01

2.41 ± 0.02

2.52 ± 0.02

Co

BDL

0.10 ± 0.006

0.15 ± 0.008

0.15 ± 0.001

Pb, Cd, Cr, As, Hg—Below detection limit (BDL)

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successively reduced to 70.86% after 1st yr of plantation followed by 68.96% after 2nd yr and 64.46% after 3rd yr of plantation. In contrary, the non-gravely finer fraction ( summer. The corresponding values of these nutrients were in the range 0.047–0.051%, 127–138 ppm, 598–700 ppm, 304–339 ppm, 765–887 ppm and 485–556 ppm, respectively. The maximum nutrient concentration obtained in monsoon season probably because of the deposition of silt particles washed out from rains from the nearby areas. As such, the physicochemical properties of the riparian soil along the river corridor are within the normal range of Indian soils [75, 76].

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Table 7 Seasonal variation in physicochemical characterization of riparian soil (mean ± SE are given) Parameter

Summer

Winter

Monsoon

Sand (%)

58.6 ± 4.3

59.6 ± 3.5

61.3 ± 4.5

Silt (%)

29.0 ± 2.6

28.4 ± 2.3

27.5 ± 2.4

Clay (%)

12.4 ± 1.0

12.0 ± 1.1

11.2 ± 0.98

Bulk Density (g/cc)

1.36 ± 0.1

1.30 ± 0.2

1.28 ± 0.1

WHC (%)

28.4 ± 1.2

29.8 ± 1.7

30.6 ± 1.9

Porosity (%)

33.5 ± 2.3

34.7 ± 2.9

35.9 ± 3.2

EC (dS/m)

0.048

0.05

0.043

Dehydrogenase Activity (mg/Kg/hr)

1.98 ± 0.01

2.01 ± 0.01

1.86 ± 0.01

pH

6.6

6.8

6.9

Organic C (%)

0.46 ± 0.02

0.49 ± 0.03

0.53 ± 0.03

N (%)

0.051 ± 0.003

0.049 ± 0.002

0.047 ± 0.002

kg−1 )

135 ± 8.9

138 ± 9.5

127 ± 8.2

K (mg kg−1 )

700 ± 22

675 ± 18

598 ± 15

S (mg kg−1 )

326 ± 16

339 ± 18

304 ± 16

kg−1 )

875 ± 64

887 ± 68

765 ± 56

Mg (mg kg−1 )

540 ± 34

556 ± 32

485 ± 29

Total major nutrients

P (mg

Ca (mg

3.2.2

Characteristics of Vegetation in the Plot

The selected riparian herbs grown in monoculture on artificial slopes varied considerably in respect of canopy cover; litter mass, standing crop biomass and antecedent soil moisture content of the experimental plots. Among the six plots studied (five vegetated and one bare), Leonotis (Fig. 6) had the maximum canopy cover (92.3%) and antecedent soil moisture content (11.5%), however, the maximum standing crop biomass of 326 g m−2 and litter mass of 125 g m−2 were observed in case of Cassia. The other species such as Ageratum, Parthenium, and Sida were found to have their values in the range 68.9 to 78.6% for canopy cover, 135.6 to 278.5 g m−2 for biomass, 46.7 to 105.9 g m−2 for litter mass and 7.2 to 10.6% for antecedent soil moisture content. Further the moisture content was minimum (6.7%) in the bare plot. Similar observations have also been reported in another study by Kumar et al. [38].

3.2.3

Water and Soil Conservation

Plant cover (canopy) protects the soil against erosion to a great extent. Simulated rain on vegetated and bare plots depleted the soil quantities differently. The minimum water loss (14.9 mm) and soil loss (85.6 gm−2 ) and maximum water CV (48.6%) and soil CV (76.8%) were observed in Leonotis stand (Table 8). The soil and water CV of

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Fig. 6 Characteristics of selected Riparian land where artificial showering experiments were conducted Table 8 Soil and water loss and conservation value of selected riparian species (mean ± SE are given) Parameter

Bare

Vegetation Leonotis

Soil loss (g 589.3 ± 5.2 85.6 ± 2.6 m−2 )

Cassia

Ageratum

Parthenium

Sida

169.4 ± 4.6 236.5 ± 4.9 269.2 ± 4.4 345.0 ± 4.7

Soil CV (%)

0

76.8 ± 0.98 74.5 ± 0.45 64.6 ± 0.5

49.5 ± 0.33 32.4 ± 4.7

Water loss (mm)

32.5 ± 0.7

14.9 ± 0.6

18.5 ± 0.8

16.2 ± 0.9

28.3 ± 0.9

33.6 ± 1.3

Water CV (%)

0

48.6 ± 1.8

39.4 ± 2.9

34.6 ± 1.1

32.5 ± 1.4

19.7 ± 2.4

other species followed the order: Cassia (74.5% and 39.4%) > Ageratum (64.6% and 34.6%) > Parthenium (49.5% and 32.5%) > Sida (32.4% and 19.7%). The reduction in soil loss and water runoff through vegetation is mainly due to the combined root, shoot and canopy effects. As the roots and shoots increase in quantity and size, the soil loss and runoff decreased rapidly. This indicated that plants played a very important role in arresting the soil erosion[77, 78]. Maximum time lag (150 s) between rainfall and run-off occurrence and maximum infiltration (58.3%) was also observed in the Leonotis stand, while the reverse was true for the bare plot (Fig. 6). In case of Ageratum, Parthenium and Sida, the values for time lag, infiltration, water runoff and soil loss were in the range 128.3–146.2 s, 42.5–52.4%, 16.2–32.5 mm, 169.4– 345.0 g m−2 respectively. Low water run-off and soil loss from the Leonotis stand

Erosion Management of Riparian Ecosystem in Coal Mining Area … Table 9 Step wise multiple Regression Equations relating canopy, litter, biomass and soil antecedent moisture content to runoff variables in relation to selected Riparian herbs; the squared multiple correlation coefficients (R2 ) are also shown

Variable

Equation

121 R2

Water loss

32.3–0.14 Cy

0.69**

Water conservation value

−1 + 0.44 Cy

0.69**

Infiltration

24.4 + 0.32 Cy

0.84**

Time lag

96.5 + 0.55 Cy

0.77**

Soil loss

613.9–4.52 Cy

0.79**

Soil conservation value

−3.6 + 0.76 Cy

0.79**

R2 values are significant: **p < 0.05; Cy: Canopy cover

(40.0% and 85.6 gm−2 ) might be ascribable to the reduction in raindrop energy by the multilayered (3–6 leaf layers) canopy cover (92.3%), whose cushioning effect was further increased when the plants blocked under the impact of the initial application of simulated rain and protected the ground more closely [77]. This is probably due to the increase in the interception of raindrops which may reduce raindrops energy approaching to the soil surface, prevent soil crusting and reduce runoff [78]. The plant roots bind the soil and reduce erosive power and increase infiltration capacity [79, 80]. This result also accords with the study of Ren et al. [81] in a simulated the rainfall-erosion process at a hill slope scale, and observed that the increase of vegetation canopy cover reduced soil loss and sediment yield significantly. Unlike, in the bare plot, an intense splashing and beating effects on the surface soil by high energy raindrops caused finer particles to come on the surface. It resulted the clogging and sealing of the pore spaces and changed the structure and textural composition of the surface soil layer leading to maximum loss of water and soil through water run-off [79, 81]. In stepwise multiple regression (Table 9) using canopy cover, litter mass, plant biomass and soil antecedent moisture content as independent variables, canopy cover explained 79% in soil CV, 69% variation in water CV, 77% in time lag and 84% of the variation in infiltration (p < 0.05).

4 Conclusions The above interpretation, observations, results and discussions support the following conclusions: 1.

2.

Considerable improvement of mine spoil in respect of physicochemical and biological characteristics has been noticed during different growth stages after the plantation. Overall growth condition of all the planted species was luxuriant with approximately 90–95% survival rate. Although Dalbergia sissoo, Albizia lebbeck, Delonix regia etc. among hardy species and Vetiveria zizanioides and Cymbopogan flexuosus among the herbaceous vegetation are quite suitable and dominating in respect of their canopy characteristics.

122

3. 4.

5. 6. 7.

8. 9.

N. K. Srivastava and R. C. Tripathi

Among the studied plant species, Dalbergia sissoo had maximum photosynthetic rate followed by Albizia lebbeck and Acacia auriculaeformis. Among the herbs, Cymbopogon flexuosus has shown maximum water and soil conservation efficiencies (68 & 92%, respectively) while among the hardy species, Dalbergia sissoo and Albizia lebbeck have shown quite high soil and water conservation efficiencies (71.4 & 62.0% and 48.2 & 42.6%, respectively). The ambient CO2 concentration is considerably reduced up to 17% as compared to bare site. A significant reduction in the concentration of particulates and other gaseous pollutants has been noticed. The quantum of soil, water and nutrient losses is several folds higher from the bare plots than the vegetated plots from the sloping and undulating areas. Consequently the conservation efficiency is more from the vegetated plots. Among the species, the soil and water CV varied in the order Leonotis > Cassia > Ageratum > Parthenium > Sida. The canopy cover is the single most important factor explaining up to 88–97% (P < 0.01) of variation in overall conservation values as the vegetal cover lowered the rain beating effects, prevent the soil movement through surface runoff.

5 Recommendations The mine soil (initially devoid of fertility status) could be successfully reclaimed together with improved physicochemical characteristics and enhanced nutrient status/biological activity of the mine spoil besides reducing the erosional losses significantly. Sequestration of CO2 i.e. the emission of one of the major GHG’s is significantly minimized, leading to a better and cleaner environment in the coal mining areas. In fact, by using this phyto-reclamation technology, the overburden dumps in other coalfields can also be reclaimed on sustainable basis thereby solving the vexing problem of ever-increasing GHGs from the surrounding environment besides turning the overlaying waste dumps to resource through the plantation of forestry and other species having high economic value. The riparian vegetation played the important roles in conserving the nutrient losses (N&P) from the slopes though water runoff and soil loss. The physical, biological and hydrological factors (precipitation, rainfall and evapotranspiration) interact together to determine the concentration of nutrients. It may be suggested that the protection of riparian slopes in respect of soil erosion, water runoff and nutrient loss, native herbs with greater canopy cover and high soil binding capacity may be planted. Acknowledgements The authors are thankful to Ministry of Coal, Govt. of India and Dept. of Science & Technology, Govt of India for financial support in the form of R&D project and Director, CSIR-CIMFR for permitting to publish this paper.

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References 1. Harun, S. M., Roy, D. R., Hossain, M. S., Islam, M. S., Hoque, M. M. M. & Zannat Urbi, Z. (2014). Impact of coal mining on soil, water and agricultural crop production: a crosssectional study on Barapukuria coal mine industry, Dinajpur. Bangladesh. Research Journal of Environmental Sciences, 1(1), 1–6. 2. Festin, E. S., Tigabu, M., Chileshe, M. N., Syampungani, S. & Oden, P. C. (2019). Progresses in restoration of post-mining landscape in Africa. Journal of Forestry Research, 30(2), 381–396. 3. Sheoran, V., Sheoran, A. S., & Poonia, P. (2010). Soil reclamation of abandoned mine land by revegetation: A review. International Journal of Soil, Sediment and Water, 3(2), Art. 13 ISSN: 1940–3259. https://scholarworks.umass.edu/intljssw/vol3/iss2/13. 4. Poncelet, D. M., Cavender, N., Cutright, T. J. & Senko, J. M. (2014). An assessment of microbial communities associated with surface mining-disturbed overburden. Environmental Monitoring and Assessment, 3, 1917–1929. 5. Upadhyay, N., Verma, S., Singh, P., Devi, S., Vishwakarma, K., Kumar, N., Pandey, A., Dubey, K., Mishra, R., Tripathi, D. K., Rani, R., & Sharma, S. (2016). Soil ecophysiological and microbiological indices of soil health: a study of coal mining site in Sonbhadra, Uttar Pradesh. Journal of Soil Science and Plant Nutritionis, 16(3), 778–800. 6. Wali, M. K. (1999). Ecological succession and the rehabilitation of disturbed terrestrial ecosystems. Plant and Soil, 213(1/2), 195–220. 7. Kappes, H., Clausius, A. & Topp, W. (2012). Historical small-scale surface structures as a model for post-mining land reclamation. Restoration Ecology, 20, 322–330. 8. Wong, M. H. (2003). Ecological restoration of mine degraded soils, with emphasis on metal contaminated soils. Chemosphere, 50, 775–780. 9. Xia, H. P. & Cai, X. A. (2002). Ecological restoration technologies for mined lands: A review. Chinese Journal of Applied Ecology, 13, 1471–1477. 10. Ghose, M. & Majee, S. (2000). Assessment of dust generation due to opencast coal mining– an indian case study. Environmental Monitoring and Assessment, 61, 257–265. 11. Goswami, S. (2014). Environmental Impact assessment of coal mining: Indian scenario. European Researcher, 83, 1651–1661. 12. Thomas, A. D., Elliott, D. R., Dougill, A. J., Stringer, L. C., Hoon, S. R. & Sen, R. (2018). The influence of trees, shrubs, and grasses on microclimate, soil carbon, nitrogen, and CO2 efflux: Potential implications of shrub encroachment for Kalahari rangelands. Land Degradation and Development, 29, 1306–1316. 13. Corrêa, R. S., Balduíno, A. P. C., Teza, C. T. V. & Baptista, G. M. M. (2018). Vegetation cover development resulting from different restoration approaches of exploited mines. Floresta e Ambiente, 25(4), e20171116. E. pub https://doi.org/10.1590/2179-8087.111617. 14. Singh, A. N., Raghubanshi, A. S. & Singh, J. S. (2002). Plantations as a tool for mine spoil restoration. Current Science, 82(12), 1436–1441. 15. Sheoran, A. S., Sheoran, V., & Poonia, P. (2008). Rehabilitation of mine degraded land by metallophytes. Mining Engineers Journal, 10(3), 11–16. 16. Soares, J. C., Santos, C. S., Carvalho, S. M. P., Pintado, M. M. & Vasconcelos, M. W. (2019). Preserving the nutritional quality of crop plants under a changing climate: Importance and strategies. Plant and Soil, 443, 1–26. 17. Ramos, S. J., Caldeira, C. F., Gastauer, M., Costa, D. L. P., Neto, A. E. F., de Souza, F. B. M., Souza-Filho, P. W. M. & Siqueira, J. O. (2019). Native leguminous plants for mineland revegetation in the eastern Amazon: seed characteristics and germination. New Forests 50, 859–872. 18. Merino, C., Nannipieri, P. & Matus, F. (2015). Soil carbon controlled by plant, microorganism and mineralogy interactions. Journal of Soil Science and Plant Nutrition., 15, 321–332. 19. Gastauer, M., Silva, J. R., Junior, C. F., Ramos, S. J., Filho, P. W. M. S., Neto, A. E. F. & Siqueira, J. O. (2018). Mine land rehabilitation: Modern ecological approaches for more sustainable mining. Journal of Cleaner Production, 172, 1409–1422.

124

N. K. Srivastava and R. C. Tripathi

20. Martínez-Ruiza, C. & Fernández-Santos, B. (2005). Natural revegetation on top soiled miningspoils according to the exposure. Acta Oecologica, 28, 231–238. 21. Lázaro-Lobo, A. & Ervin, G. N. (2021). Native and exotic plant species respond differently to ecosystem characteristics at both local and landscape scales. Biological Invasions, 23, 143–156. 22. Buckley, Y. M. & Catford, J. (2016). Does the biogeographic origin of species matter? Ecological effects of native and non-native species and the use of origin to guide management. Journal of Ecology, 2016(104), 4–17. 23. Mensah, A. K. (2015). Role of revegetation in restoring fertility of degraded mined soils in Ghana: A review. International Journal of Biodiversity and Conservation, 7(2), 57–80. 24. Soumare, A., Diedhiou, A. G., Thuita, M., Hafidi, M., Ouhdouch, Y., Gopalakrishnan, S. & Kouisni, L. (2020). Exploiting biological nitrogen fixation: A route towards a sustainable agriculture. Plants, 9, 1011. https://doi.org/10.3390/plants9081011. 25. Nunes, L. J. R., Meireles, C. I. R., Pinto Gomes, C. J. & Almeida Ribeiro, N. M. C. (2020). Forest contribution to climate change mitigation: management oriented to carbon capture and storage. Climate, 8, 21. https://doi.org/10.3390/cli8020021. 26. Skousen, J. & Zipper, C. (2014). Post-mining policies and practices in the Eastern USA coal region. International Journal of Coal Science and Technology, 1, 135–151. 27. Macdonald, S. E., Landhausser, S. M., Skousen, J., Franklin, J., Frouz, J., hall, S., Jacobs, D. F. & Quideau, S. (2015). Forest restoration following surface mining disturbance: Challenges and solutions. New Forests, 46, 703–732. 28. Zipper, C. E., Burger, J. A., McGrath, J. M., Rodrigue, J. A. & Holtzman, G. I. (2011). Forest restoration potentials of coal mined lands in the eastern United States. Journal of Environmental Quality, 40, 1567–1577. 29. Dosskey, M. G., Vidon, P., Gurwick, N. P., Allan, C. J., Duval, T. P. & Lowrance, R. (2010). The role of riparian vegetation in protecting and improving chemical water quality in streams. JAWRA Journal of the American Water Resources Association, 46(2), 261–277. 30. Cole, L., Stockan, J. & Helliwell, R. (2020). Managing riparian buffer strips to optimise ecosystem services: A review. Agriculture, Ecosystems and Environment, 296, 106891. https:// doi.org/10.1016/j.agee.2020.106891. 31. Zhao, Q., Ding, S., Liu, Q., Wang, S., Jing, Y. & Lu, M. (2020). Vegetation influences soil properties along riparian zones of the Beijiang River in Southern China. Peer Journal, 8, e9699. https://doi.org/10.7717/peerj.9699 32. Connolly, N. M., Pearson, R. G. & Pearson, B. A. (2016). Riparian vegetation and sediment gradients determine invertebrate diversity in streams draining an agricultural landscape. Agriculture Ecosystems and Environment, 221, 163–173. 33. Fierro, P., Bertrán, C., Tapia, J., Hauenstein, E., Peñacortés, F., Vergara, C., Cerna, C. & Vargaschacoff, L. (2017). Effects of local land-use on riparian vegetation, water quality, and the functional organization of macro invertebrate assemblages. Science of the Total Environment, 609, 724–734. 34. Sun, D., Zhang, W., Lin, Y., Liu, Z., Shen, W., Zhou, L., Rao, X., Liu, S., Cai, X., He, D. & Fu, S. (2018). Soil erosion and water retention varies with plantation type and age. Forest Ecology and Management, 422, 1–10. 35. Dominika, K., Tjibbe, K., Kamilla, S. & Jannes, S. (2019). Effect of riparian vegetation on stream bank stability in small agricultural catchments. CATENA, 172, 87–96. 36. Xu, S., Zhao, Q., Ding, S., Qin, M., Ning, L. & Ji, X. (2018). Improving soil and water conservation of riparian vegetation based on landscape leakiness and optimal vegetation pattern. Sustainability, 10, 1571. https://doi.org/10.3390/su10051571. 37. Boudell, J. A., Dixon, M. D., Rood, S. B. & Stromberg, J. C. (2015). Restoring functional riparian ecosystems: Concepts and applications. Ecohydrol., 8, 747–752. 38. Kumar, R., Ambasht, R. S., Srivastava, A. & Srivastava, N. K. (1996). Role of some riparian wetland plants in reducing erosion of organic carbon and selected cations. Ecological Engineering, 6, 227–239. 39. Piper, C. S. (1950). Soil & plant analysis. The University of Adelaide.

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40. Black, C. A. (Ed.). (1965). Methods of soil analysis Part1 and 2. American Society of Agronomy Inc. 41. Jackson, M. L. (1967). Soil chemical analysis. Prentice Hall of India, Pvt. Ltd. 42. Tandon, L. (1995). Methods of analysis of soils, plants waters and fertilizers. fertilizer development and consultation organization. 43. Linderman, R. G. (1992). Mycorrhizae in sustainable agriculture, ASA Special Publ. No. 54. American Society of Agronomy. 44. Klein, D. A., Loh, T. C. & Goulding, R. L. (1971). A Rapid Procedure to Evaluate Dehydrogenase Activity of Soils Low in Organic Matter. Soil Biology and Biochemistry, 3, 385–387. 45. Ambasht, R. S. (1970). Conservation of soil through plant cover of certain alluvial slopes in India. In Proceedings of IUCN. Morges. 46. IS: 5182 (Part IV) (2005). Methods for Measurement of Air Pollution (Suspended Matter). Bureau of Indian Standard. 47. IS: 5182 (Part II) (2001). Indian standard method for measurement of air pollution Part 2 (Sulphur dioxide). Bureau of Indian Standard. 48. IS: 5182 (Part VI) (2006). Indian standard method for measurement of air pollution Part 6 (Nitrogen oxides). Bureau of Indian Standard. 49. Gates, C. E., Marshall, W. H. & Olson, D. P. (1968). Line transect method of estimating grouse population densities. Biometrics, 24, 135–145. 50. Russel, D., Scott, F. & Eisensmith, P. (1991). MSTAT (version 1.41) Computer programme, Crop and Soil Department. Michigan State University. 51. Duan, A., Lei, J., Hu, X., Zhang, J., Du, H., Zhang, X., Guo, W. & Sun, J. (2019). Effects of planting density on soil bulk Density, pH and nutrients of un-thinned Chinese Fir mature stands in South Subtropical region of China. Forests, 10, 351–368. 52. Tayler, E. M., Jr. & Schumann, G. E. (1988). Fly ash and lime amendment of acidic coal spoil to aid revegetation. Journal of Environmental Quality, 17, 120–124. 53. Yaseen, S., Pal, A., Singh, S. & Dar, I. Y. (2012). A Study of physicochemical characteristics of overburden dump materials from selected Coal mining areas of Raniganj Coal Fields, Jharkhand. Global Journal of Science Frontier Research, 2, 6–13. 54. Maharana, J. (2013). Physicochemical characterization and mine soil genesis in age series coal mine overburden spoil in chrono-sequence in a dry tropical environment. Journal of Phylogenetics and Evolutionary Biology, 01(01). 10.4172/ 2329–9002.1000101. 55. Malakar, S. & Joshi, H. G. (2018). Successional changes in some physicochemical properties on an age series of overburden dumps in Raniganj Coalfields, West Bengal, India. In Book: Advances in growth curve and structural equation modeling (pp.101–112). https://doi.org/10. 1007/978-981-13-1843-6_6. 56. Dora, N. (2019). The role of soil pH in plant nutrition and soil remediation. Applied and Environmental Soil Science, 2019, Article ID 5794869, 9. https://doi.org/10.1155/2019/579 4869. 57. Bhat, R., Dervash, M., Mehmood, M., Skinder, B., Rashid, A., Bhat, J., Singh, D. & Lone, R. (2017). Mycorrhizae: A sustainable industry for plant and soil environment (pp. 473–502). https://doi.org/10.1007/978-3-319-68867-1_25. 58. Javaid, A. (2009). Arbuscular mycorrhizal mediated nutrition in plants. Journal of Plant Nutrition, 32, 1595–1618. 59. Buta, M., Blaga, G., Paulette, L., Ioan P˘acurar, I., Rosca, S., Borsai, O., Florina Grecu, F., Sînziana, P.E. & Negrusier, C. (2019). Soil reclamation of abandoned mine lands by revegetation in northwestern part of Transylvania: A 40-year retrospective study. Sustainability, 11, 3393. https://doi.org/10.3390/su11123393. 60. Roden, J. S. & Ball, M. C. (1996). The effect of elevated [CO2 ] on growth and photosynthesis of two Eucalyptus species exposed to high temperatures and water deficits. Plant Physiology, 111, 909–919. 61. Potts, D. L., Minor, R. L., Braun, Z. & Barron-Gafford, G. A. (2017). Photosynthetic phenological variation may promote coexistence among co-dominant tree species in a Madrean sky island mixed conifer forest. Tree Physiology, 37(9), 1229–1238.

126

N. K. Srivastava and R. C. Tripathi

62. Annan, H., Golding, A.L., Zhao, Y. & Zhongmin Dong, Z. (2012). Choice of hydrogen uptake (Hup) status in legume-rhizobia symbioses. Ecology and Evolution, 2(9), 2285–2290. 63. Niinemets, Ü. (2016). Leaf age dependent changes in within-canopy variation in leaf functional traits: A meta-analysis. Journal of Plant Research, 129(3), 313–338. 64. Venkatraman, K. & Ashwath, N. (2016). Transpiration in 15 tree species grown on a phytocapped landfill site. Hydrology: Current Research, 7, 236–249. https://doi.org/10.4172/21577587.100023 65. Daszkowska-Golec, A. & Szarejko, I. (2013). Open or close the gate - stomata action under the control of phytohormones in drought stress conditions. Frontiers in Plant Science, 4, 138. https://doi.org/10.3389/fpls.2013.00138 66. Katul, G., Manzoni, S., Palmroth, S. & Oren, R. (2010). A stomatal optimization theory to describe the effects of atmospheric CO2 on leaf photosynthesis and transpiration. Annals of Botany, 105(3), 431–442. 67. Lawson, T. & Blatt, M. R. (2014). Stomatal size, speed, and responsiveness impact on photosynthesis and water use efficiency. Plant Physiology, 164(4), 1556–1570. https://doi.org/10. 1104/pp.114.237107. 68. Digrado, A., Mitchell, N. G., Montes, C. M., Dirvanskyte, P. & Ainsworth, E. A. (2020). Assessing diversity in canopy architecture, photosynthesis, and water-use efficiency in a cowpea magic population. Food Energy Security, 9, 236–255. https://doi.org/10.1002/fes3.236 69. Ferrini, F. & Fini, A. (2011). Sustainable management techniques for trees in the urban areas. Journal of Biodiversity and Environmental Sciences, 1, 1–20. 70. Ferrini, F., Fini, A., Mori, J. & Gori, A. (2020). Role of vegetation as a mitigating factor in the urban context. Sustainability, 12, 4247. https://doi.org/10.3390/su12104247. 71. Pandey, B., Agrawal, M. & Singh, S. (2013). Assessment of air pollution around coal mining area: Emphasizing on spatial distributions, seasonal variations and heavy metals, using cluster and principal component analysis. Atmospheric Pollution Research, 5, 79–86. https://doi.org/ 10.5094/APR.2014.010 72. NAAQ. (2020). National Ambient Air Quality Status and Trends 2019. NAAQMS/45/ 2019– 2020. Central Pollution Control Board, Ministry of Environment, Forest and Climate Change, Govt. of India. www.cpcb.nic.in., p. 156. 73. Pierret, A., Maeght, J. L., Clément, C., Montoroi, J. P., Hartmann, C. & Gonkhamdee, S. (2016). Understanding deep roots and their functions in ecosystems: An advocacy for more unconventional research. Annals of Botany, 118(4), 621–635. 74. Vaezi, A. R., Ahmadi, M. & Cerdà, A. (2017). Contribution of raindrop impact to the change of soil physical properties and water erosion under semi-arid rainfalls. Science of the Total Environment, 583, 382–392. 75. ICAR (Indian Council of Agricultural Research). (2019). Hand Book of Agriculture (12th Reprint of 6th Ed.) ICAR, New Delhi. 76. Singh, S. K. & Ahmad, I. (2004). Seasonal variation in certain chemical properties of the soil of a freshwater pond of Dholi (Muzaffarpur), Bihar, India. Journal of Applied Biology, 14, 53–55. 77. Gyssels, G. & Poesen, J. (2003). The Importance of plant root characteristics in controlling concentrated flow erosion rates. Earth Surface Processes and Landforms, 28, 371–384. 78. Zhou, Z. C. & Shangguan, Z. P. (2007). The effects of ryegrass roots and shoots on loess erosion under simulated rainfall. CATENA, 70, 350–355. 79. Zuazo, D. V. & Rodriguez, C. (2008). Soil-erosion and runoff prevention by plant covers: A review. Agronomy for Sustainable Development, 28, 65–86. 80. Pan, C. Z. & Shangguan, Z. (2006). Runoff hydraulic characteristics and sediment generation in sloped grass plots under simulated rainfall conditions. Journal of Hydrology, 331, 178–185. 81. Ren, K., Wei, W., Zhao, X., Feng, T., Chen, D. & Yu, Y. (2018). Simulation of the effect of slope vegetation cover and allocation pattern on water erosion in the loess hilly region. Acta Ecologica Sinica, 38, 8031–8039.

Waste to Energy

Urban Solid Waste Management for Enhancement of Agricultural Productivity in India Rana Rishi and Ganguly Rajiv

Abstract Management of solid waste poses a great challenge and is a global problem being faced by all the developed as well as developing countries. The population living in cities is rising worldwide, which has led to the accelerated solid waste generation. In major Indian cities, an enormous amount of organic waste is generated from day to day activities which remain unutilized and is either burnt or dumped in open sites creating health and environmental hazards. In the present paper, the aspects of solid waste management pertaining to the agricultural application in India are reviewed. Total waste generation in India is around 62 million tons every year, of which less than 60% is collected and around 15% is processed. More than 50% of this waste generated consists of biodegradable matter. Instead of disposing this organic waste, it can be effectively recycled and used as compost to meet the nutritional requirements of the crops. Many studies have shown that the effect of using the chemical and synthetic fertilizers have led to decreasing in the nutritional value of the crops. Excessive use of chemical fertilizers has not only proven to become expensive, but also they get accumulated in the soil and causes bio-magnification leading to various health and environmental menaces. The application of the treated organic waste as a nutrient supplier, fertilizer, compost, etc. will help promote its effective use in agricultural enhancement but will also be useful in solving the problem of disposal. Still, the effects of the waste materials in terms of the presence of heavy metals, organic pollution, etc. must be taken into account. Keywords Solid waste management · Chemical Fertilizers · Compost · Nutritional Value

R. Rishi · G. Rajiv (B) Department of Civil Engineering, Jaypee University of Information Technology, Waknaghat 173234, District Solan, Himachal Pradesh, India e-mail: [email protected] R. Rishi e-mail: [email protected] © Springer Nature Switzerland AG 2022 S. Yadav et al. (eds.), Environmental Management in India: Waste to Wealth, https://doi.org/10.1007/978-3-030-93897-0_7

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1 Introduction In the process of fulfilling the ever-increasing demand and necessities of the locale, massive consumption patterns and depletion of natural assets has led to the generation of huge amount of waste. Fast development and mechanization in the advanced as well as emerging countries has added a major blow to the waste generation which in turn poses a major problem in collection, conveyance, handling and discarding of waste [6, 23, 29, 34]. Waste organization is a significant concern worldwide [26, 32, 33, 36, 37]. The waste generated is directly related to the growth and commercial expansion. Developed countries tend to produce more waste than the emerging countries, but the management of waste is more of a problematic situation for the developing countries. India produces around 50 million tons of municipal solid wastes from every city. India is the world’s second utmost populated country with a population of 1.33billion [7, 20, 22]. The annual growth rate of the urban population in India is 1.2% [7]. This tremendous increase in the urban population of a developing country like India has become a major challenge for the urban local bodies (ULBs) for managing the waste properly. The ever-increasing populace is placing massive burden on the demand of foodstuff, housing and the natural assets [5, 9, 12, 13, 15, 16, 19, 34]. The unexpected immigration of the people has also led to the formation of slums and casual housing all around the cities of the developing nations. Urbanization directly linked with the increase in the generation of waste and further the unscientific handling of the waste will cause degradation of the urban environment as well as health hazards (Fig. 1). The amount of generation of solid waste is dependent on the socio-economic status of the urban population. The per capita generation of waste in India is estimated to rise at a rate of 1–1.33% annually. The classification of the term solid waste varies from country to country. Since the composition of the solid waste differs, and the nature

Fig. 1 Current Status of Urban Solid Waste Generation and Projected Growth

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Fig. 2 Sources of Solid Waste

of the waste generated is dependent upon the type of components present. Therefore, the level of toxicity and hazard will be different. Henceforth, the integrated solid waste management is the necessity of the hour and has emerged as an essential and specialized sector for making countries and cities healthy and livable. Figure 2 shows the different sources of solid waste. Wastes arising from typically the urban societies include garbage, rubbish, construction and demolition wastes, leaf litters and hazardous waste [1, 3, 4, 9, 14, 17, 21, 25, 31, 34]. According to the up-to-date report of the central pollution control board [8], India generates around 135198 TPD (tons per day), out of which 1, 11,028 TPD is collected, 25,572 TPD treated and 47,456 TPD land-filled. The solid waste management system is governed by the Municipal authorities or municipalities in the urban cities and towns and is bound to follow the Solid Waste Management Rules, 2016 [24]. The enactment of these rules is a foremost concern of the ULB?s across the country. Efficient solid waste management is a blend and interrelationship of waste generation, gathering, storage, transport, and ultimate disposal, as shown in Fig. 3. Almost all the municipalities lack the basic amenities. Moreover there is no distinct sector for the handling of waste management. This leads to the failure in attaining an effective and dynamic system. In most of the developing nations including, India, wastes are either scattered in urban centers or disposed of unscientifically in open sites [10, 11, 16]. The solid waste management is one of the biggest challenges causing several environmental issues in Indian megacities [24, 27, 29]. Clear governmental policies and competent bureaucracies are urgently needed for the management of solid wastes, especially for a developing country like India. A survey conducted by three major research institutes CPCB [41], NEERI and CEPT, has reported that about 52,592 tonnes of waste are generated in the 59 selected cities. In India, more than 90% of the budget allocated for solid waste management is spent on assemblage system, and yet the collection efficiency is very poor [2,

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Fig. 3 Interrelationship of Functional Elements of Solid Waste Management System (Peavy and Tchobanoglous 1985)

9, 28, 29, 34]. Another survey revealed that big urbanized municipalities generate about 1000 TPD of solid waste, whereas smaller cities generate less than 450 TPD of solid waste. The survey has also exposed the lack of an suitable number of sanitary landfills available in Indian cities. The least amount from the total budget is kept for treatment and final disposal of waste. The unscientific management and disposal of wastes lead to serious environmental problems [17]. For operative waste management organization knowledge of data including the quantity, quality, and composition of waste is of foremost importance. All these parameters are dependent on the factors like the standard of living, seasonal variations, food habits, and socio-economic condition of the areas. A study [34] conducted highlighted that every year 11.2 billion tons of solid wastes are collected globally. Modern urban livings generate more waste due to the easy availability of packaged goods and products which leads to increase in the quantity of waste [9]. The typical generation of waste from urban Indian cities is estimated to have 40 to 60% organic matter which can be utilized in the form of compost [28, 35]. However, due to the unavailability of the appropriate techniques as well as financial constraints the waste is dumped in open or low-lying areas creating an environmental nuisance and adverse health impacts. A research study conducted by NEERI, over the characterization of Indian waste depicted that waste has large organic content

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(30?40%), ash content (3?6%) along with plastics and metal (each less than 1%). The presence of the organic matter in the waste in such huge quantities is responsible for the unpleasant odor and since they occupy a large area part of land area which can also lead to the groundwater contamination [1, 14, 17, 31, 34]. Organic waste is one of the major streams of the solid wastes [1, 14, 17, 31, 34]. Organic waste comprises of food, garden trimmings as well as animal and plant-based degradable materials [26, 32, 33, 36, 37]. The composition of waste plays a significant role and tends to vary among the different countries, regions, and cities which are the main reason leading to a difference in the composition of solid waste among developed and developing countries. Therefore it becomes significantly important to acquire data about the nature and composition of the waste [1, 14, 17, 26, 31–34, 36, 37]. Composition of waste is also dependent upon the income level of countries and cities. Studies [1, 14, 17, 31, 34] have shown that the low-income country a has high percentage of organic matter, low calorific value and moisture content whereas high-income countries show comparatively low moisture content and organic matter [1, 3, 9, 21, 25]. An overview of the composition of urban solid waste from Indian cities is presented in Table 1. Huge amount of untreated waste from residential, industrial and agricultural sectors are directly dumped into the soil which releases toxic metals like lead, mercury, nickel, mercury and cadmium leading to contamination of soil and groundwater [1, 3, 9, 21, 25]. Agriculture is the backbone of our entire nation. In the present day situation, keeping in view the cumulative urbanization and population, the farmers now a day are using many chemical fertilizers to increase the yield of the crops. Although usage of these fertilizers helps in increasing the yield of the crops, they permanently damage the soil. Agriculture faces numerous challenges creating a more difficult situation in achieving its prime objective of feeding the population of the world [34]. Though solid waste being a negative concern, it does provide many opportunities which help in mitigating the negative impacts and also providing job prospects. Keeping the present situation in mind, authors have reviewed the aspects of solid waste management pertaining to the agricultural application.

2 Environmental Impacts of Solid Waste Disposing of the waste without any prior treatment will generate negative impacts on human health as well as on the various constituents of the environment like soil, water, and air. In India, unscientific methods of disposal of waste are being followed, and it has been described that around 90% of the waste generated is disposed of openly in the dumping grounds. Figure 3 gives an outline of the environmental effects owing to the irrational disposal of solid waste. Continuous increase in the rate of generation of waste, its composition, and its ill management along with the laid back attitude of public has led to various health impacts [27, 28]. The potential risk to health mainly concerns the workers who are directly working in the field. These health issues may be due to the inhalation of

3.0

5.0

4.0

Ludhiana

Pune

Surat

* Values

in %

11.0

4.0

Lucknow

Puducherry

6.0

Jaipur

10.0

7.0

Hyderabad

Kolkata

6.8

12.0

Mumbai

Delhi

10.0

8.0

Bhopal

6.0

Bengaluru

Paper*

Ahmadabad

City

4.0

5.5

5.0

–

6.0

2.0

2.0

1.7

5.6

4.6

5.0

5.0

1.0

Textile*

–

0.5

–

–

–

–

–

–

0.6

0.4

2.0

–

–

Leather*

2.0

1.7

3.0

5.0

5.0

4.0

1.0

1.3

1.5

2.0

2.0

6.0

3.0

Plastic*

Table 1 Composition of urban solid waste in Indian cities [41]

0.2

0.4

–

–

2.0

1.0

–

–

2.9

–

–

3.0

–

Metals*

1.5

1.6

3.0

10.0

–

–

2.0

?

1.7

0.2

1.0

6.0

–

Glass*

26.0

50.0

45.0

15.0

50.0

50.0

47.0

5.0.0

51.5

44.0

35.0

27.0

50.0

Ash*

50.0

51.0

40.0

55.0

45.0

49.0

45.0

51.0

54.0

62.0

52.0

52.0

41.0

Organic Matter*

54.0

46.0

30.0

40.0

50.0

60.0

40.0

50.0

50.0

54.0

43.0

35.0

32.0

Moisture content*

134 R. Rishi and G. Rajiv

Urban Solid Waste Management for Enhancement of Agricultural Productivity in India

135

the smoke or fumes arising from the burning and decomposition of the waste. The poor outlook of the waste producers has made the condition more infuriating. Many researchers [6, 23, 34] have reviewed that people residing or working nearby the dumping sites are more prone to the diseases caused by the pathogenic agents like plague, cancers, cholera, respiratory ailment, etc. Studies conducted by World Health Organization [39] showed that landfills and incinerators cause health problems like cancer, and this was further supported by such study undertaken [6, 23, 34], which stated the damage of lung function of the personnel?s in the Okhla landfill, Delhi. Owing to the unplanned attitude, lack of responsiveness, and work culture, waste handlers are exposed to numerous threats produced by solid waste. Improper handling of solid waste is a major hazard to the environment. Many studies [6, 23, 27, 28, 34] have shown that the areas nearby the landfill have a greater possibility of groundwater contamination due to the generation of leachate which acts as a potential pollution source. Leachate is defined as the liquid originating from the waste which has the extracted material present in the waste. The country is facing water crisis, and on the other hand, due to the improper handling of waste, the drinking water is getting polluted. Study [10, 11, 16, 27, 28] conducted to study the physio-chemical parameters of groundwater and leachate from dumping site in Tamil Nadu stated that the leachate alters the quality of groundwater. Therefore, there is a dire need to consider the availability of the resources as well as threat to the groundwater. The problem gets further enhanced as landfills have the potential to generate the leachate for many numbers of years even after the closure of the landfill site. The harmful contaminants from leachate enter the food chain through the vegetation, which is grown in the nearby place of the landfill site magnifying its effect. Growth along with industrialization had laid the burden of solid waste on land, which in turn badly affects the properties of soil. Various studies [1, 14, 17, 26, 31–34, 36, 37] have reported about the increased concentration and presence of toxic heavy metals like cadmium (Cd), Arsenic As), Lead (Pb), Chromium (Cr) and Zinc (Zn) in the soil samples (Fig. 4). The production of gases from the solid waste is characterized by the rate of decomposition of the biodegradable matter present in the waste. Gases which are generated from the landfills include ammonia, carbon dioxide, carbon monoxide, methane, nitrogen, etc. Out of all these gases, methane and carbon dioxide act as principal gases, and both of them have global warming potential (GWP). Researchers [4, 17, 34] have studied the GWP of these gases from the landfill sites in Chennai, and Tamil Nadu and have reported that emission flux ranged from very high values in the landfills. Similarly, few other researchers [34, 36, 37] have also assessed the methane emission inventory from the dumping site at Okhala, New Delhi and have testified that more than 800 Gigagram (Gg) of methane emissions have been reported from the landfill site [10, 11]. Though, due to lack of proper data, the quantity of landfill gas emission could not be ascertained. Appropriate and scientific measures must be ensured for collecting the landfill gas to avert its direct release in the environment.

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Fig. 4 Environmental Impacts due to Solid Waste

3 Agricultural Productivity: Waste to Wealth to Health In developing countries especially like India, management of solid waste is a critical problem which leads to loss of resources along with increases environmental risk. Indian waste is mainly characterized by high density; high biodegradable organic matter and moisture content [29]. Agriculture is the backbone of our country. To attain the maximum yield from agriculture, farmers are using chemical fertilizers which on the long run are going to spoil and permanently damage the texture of the soil. The agriculture sector is facing many challenges making it more and more difficult to attain its primary objective of feeding the entire population. Urban solid waste contains more than 50% organic matter in waste, so composting of the waste is the best possible waste for reducing the quantity of waste leading to enrichment of the soil. Composting is the process of aerobic biological decomposition of the organic matter which takes place under controlled conditions like temperature, pH and moisture content [1, 3, 21]. It is the age-old practice of conversion of the biological content in the waste to humus-like substance, which helps in enhancement of physical, chemical, and biological properties of the soil. The stabilized end product is called as compost. Compost is a good soil conditioner as it contains major nutrients like nitrogen, potassium and phosphorus and micronutrients like copper, zinc, and iron needed by plants. It will increase the properties of soil by increasing the soil aeration and water holding capacity. Composting is considered as an option when the bulk amount of biodegradable waste is available in the waste stream, and there is a market or use of compost. This is a popular technique in Asia and Europe, as in these

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countries, intense farming creates the need for compost [1, 21, 30]. The composting method can be enhanced by the utilization of the techniques and technologies which are eco-friendly, sustainable and economically efficient [9, 25]. The production of organic fertilizer from the waste along with its utilization in the enrichment of the crop production and soil replenishment will reduce the volume of the waste, lessen the environmental pollution and degradation and escalating the efficiency of the agricultural land [14, 17, 31, 34]. This fertilizer obtained contains plant nutrients for farm production leading to a reduction in the cost of fertilizers and helps in restoring the lost fertility of the soil. The preparation of the compost from the waste is the major issue for resource management and sustainable agriculture in India. Large scale composting plants were developed in 1932 in Netherland (). These composting plants in Indian scenario may only be undertaken if the skilled labour and equipment are available else small scale level and household level composting practices are effective which also requires the people?s awareness. In India, many large scale composting facilities were set up in the cities if Delhi, Baroda, Bangalore, Mumbai, Kolkata, Kanpur, and Jaipur. The capacities of these plants ranged from 150 to 300 tonnes/day, but only around 9% of the solid waste is treated using composting [9, 25]. This is the reason that majority of the compost plants have failed to achieve the necessary provisions [14, 17, 34]. Due to the financial constraints in India, the issues such as operation and maintenance of compost plant must be made cost-effective and sustainable solutions must be followed. There are wide varieties of compost manufacturing agencies available depending upon the technologies and methods they use for producing compost. The quality of compost depends upon the factors like nature and source of waste, methods used for the preparation of compost, procedures for composting, and maturation length [34]. The compost from the waste tends to contain heavy metals, which might bioaccumulate and cause a threat to human health when transferred to the food chain. Therefore, they require special attention before application of compost in agricultural fields. The preparation and the obtained quality of the compost is the major issue for attaining sustainable agricultural solutions for India as due to the financial constraints the cost of operation and maintenance of a compost plant is higher as compared to open dumping. To achieve compost of a required standard and quality, the government of India has set up fertilizer control order (FCO). Many European countries, North America, along with India, have adopted specific standards to regulate the market of desirable quality of compost. After the thorough evaluation of the physical and chemical characteristic of the compost, fertility index (FI) and clean index (CI) can be performed which helps in setting criteria by giving a score value which depicts the levels of contamination in compost. The weighting factor for different parameters varied from 1 to 5 depending upon their importance and contribution towards soil nourishment. The higher value of CI indicates low levels of contamination by heavy metals. The parameters selected for the fertility index include total organic carbon (TOC), total nitrogen (TN), total phosphorous (TP), total potassium and carbon to nitrogen ratio and parameters selected for clean index includes the heavy metals like zinc (Zn), copper (Cu), cadmium (Cd), lead (Pb) and nickel (Ni).The selection

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Table 2 Criteria for weighing factor to fertility parameters and score value to compost [30] Fertility parameter Score value (Si )

Weighing factor (Wi )

5

4

3

2

1

TOC (% dm)

>20.0

15–20.0

12.1–15

9.1–12

1.25

1.01–1.25 0.81–1.00 0.51–0.80 0.60

0.41–0.60 0.21–0.40 0.11–0.20 1.00

0.76–1.00 0.51–0.75 0.26–0.50 66% of all sustainable power sources/supplies [6]. The coal capital of India, Dhanbad city, has only 45% organic matter in MSW imparting 10–25% energy efficiency [73]. As an example nation, an upper-middle country like Ecuador, which is a fossil-fuel dependent economy, is encouraging the use of renewable energy, reaching to an energy access index of 97.04% [60]. This is apportioned into varous sources, including thermoelectric (51%), hydrothermal (47%) and non-traditional sources (e.g., wing, sun and biomass) (2%) [3, 16, 36, 42, 55, 60]. Despite the fact that the government of Ecuadore is authorizing the utilization of sustainable assets, the utilization of food wastes to create energy can be viewed as insignificant weighed with other sustainable power sources. [6, 73]. Among biomass sources, biogas is an intriguing option with an immense potential, offering various possible options to harness the renewable energy sources for energy production and phasing-out the non-renewable energy sources [26, 61]. The significant source of energy in India is coal, with current extraction being approx 60–70% and the rest staying in worked out mines as walls and supports [31, 32]. The huge requirement of coal debilitates the supply of fuels all through the world and also increments the outflows of green house gases and a serious atmospheric pollution/impact. Improved energy security and ecological change flawlessness are the standard drivers for the difference in the power development from fossil to inexhaustible sources. Biomass needs to play a key part in ensuring a low carbon economy. Currently, 377 million individuals in urban zones generate 62 million tons of MSW in India yearly, of which > 80% is discarded unevenly at dump yards in an unhygienic way prompting human and ecological health a implications. The unexploited waste has a capacity of producing 439 MW of intensity from 32,890 tons per day (TPD) of flammable wastes including Refuse Derived Fuel (RDF), 1.3 million cubic meter of biogas every day or 72 MW of power from biogas and 5.4 million metric tons of fertilizer yearly. The current approaches, projects and administration structure do not satisfactorily address the impending test of dealing with this waste which is anticipated to be 165 million metric tons by 2031 and 436 million tons by 2050. Further, if the currently generated 62 million tons of MSW/yr keeps on being dumped without treatment, it will require 3, 40,000 cubic meter of landfill space (1240 hectare for each year). Considering the anticipated waste age of 165 million tons by 2031, the necessity of land for setting up landfill for a long time (considering

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10 m high waste heap) could be as high as 66 thousand hectares of valuable land, compromising agriultural and other activities (http://www.uncrd.or). According to Apte [8], municipal solid waste contains compostable components (products of the fruit peels, food waste), recyclables (paper, plastic, glass, metals, and so on.), harmful substances (paints, pesticides, utilized batteries, drugs), and dirtied squander (blood recolored cotton, sterile napkins, dispensable syringes) [52]. Biogas is unique in relation to other sustainable power sources, as a result of its sustainability and utilisation potential. Biogas is one of the attractive sources of energy for both rural and urban areas, because of accessible natural wastes which, in turn, also generate semisolid manure [27]. The FW can provide a significant resource for sustainable energy as a replacement for non-renewable sources [18, 25] including fossil fuels, which have contributed towards 67% of the world aggregate power supply in 2015 [41]. India installed over 4.75 million biogas plants by early 2014 (https://mnre.gov.in), with an estimated generation of biogas in the region of 2070 million cubic meters in the year 2014–2015. It is equivalent to 5% of the aggregate LPG utilization in the country [76]. As mentioned earlier, the FW is a potential resource for producing biogas via anaerobic process and generates about 55–65% of methane, 35–45% of carbon dioxide and trace amount of H2 S and moisture [67]. The calorific estimation of biogas is approx 4700 kcal or 20 MJ at approx 55% methane content [2].

2 Formation and Chemical Properties of Biogas The chemical properties of the substrate subjected to biogasification largely depends on the individual properties of the components contained in the material/waste. As the anaerobic digestion proceeds, the chemical composition of substrate changes and the end products are largely methane, carbon dioxide, water vapour and traces of hydrogen sulfide and salts.

2.1 Methane Methane is made of one carbon atom and four hydrogen atoms covalently attached to the focal molecule framing a tetrahedral molecule. Having a density of 0.72 kg/m3 , methane is lighter than air [28]. Methane formation is aided by the methanogenic bacteria in the process of biogasification. Methanogens are either hydrogenotrophs or acetogens and involve two distinctive methane-framing pathways, known as hydrogenotrophic and acetoclastic pathways [48]. The sort Methanosaeta includes species solely utilizing the acetoclastic pathway. Types of the class Methanosarcina can utilize both pathways, while different individuals from the Methanosarcinales are methylotrophs or hydrogenotrophs. Other methanogenic orders (Methanomicrobiales, Methanobacteriales, and Methanococcales) also play

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a significant role in the biogasification process using the hydrogenotrophic pathway [66]. Methane gas is delivered by methanogenic microorganisms by deteriorating natural substrate in the absence of oxygen via anaerobic absorption. It has a high calorific value of 9–11 KWh/Nm3 [28], and it can shape combustible blends with air. Therefore, higher the level of methane in biogas higher is the vitality substance of the biogas [64].

2.2 Carbon Dioxide A standout amongst the most bounteous gases in the air, carbon dioxide is made of one carbon iota and two oxygen iotas. This is a vital gas for the vegetation as this is critical for the process of photosynthesis. CO2 is created by ignition or consuming of natural substrate by microbial maturation (biogasification process). The CO2 gas, in general, constitutes around 33% of the aggregate biogas blend. In the process of biogasification, the CO2 gas is formed with CH4 , when the methanogenic microbes disintegrate the natural/organic substrate, for example, starch and unsaturated fats. Biogas blend with high CO2 can hamper the general vitality of biogas blend [15]. Similarly, high CO2 in the biogas blend can influence the pH of the biogas making it acidic. Expulsion of CO2 from biogas isn’t monetarily feasible.

2.3 Other Components Aside from the significant amount of carbon dioxide and methane, different constituents of food waste/MSW incorporate alkali, water vapour and hydrogen sulfide (H2 S) ( CoPc > NiPc, this order obeys electronegativity and d-band vacancy of the central metal. For improving ORR in MFC, FePc and CoPc was experimented and the respectively open circuit potential of 319 mV and 317 mV, established the better catalytic activity of FePc [81]. MFC with Co-naphthalocyanine (CoNPc)/C cathode reported improved ORR in comparison to Pt/C supported MFC, and recovered almost 79% of power achieved by Pt supported MFC [82]. Cobalt tetramethyl-phenylporphyrin (CoTMPP) belongs to a class of N4 macrocycles, which exhibit improved activity towards ORR and has prospect to substitute Pt as ORR catalyst. MFC incorporated with CoTMPP as cathode catalyst achieved a maximum power output of 369 mW m−2 , which was observed to be 12% lower than the power density obtained from MFC having Pt/C [83]. The MFC incorporated with CoTMPP cathode catalyst demonstrated a power density of 14.32 W m−3 , which was comparable to MFC having FePc (13.9 W m−3 ) [72]. Bimetalic phthalocyanines and porphyrins have also confirmed outstanding electrocatalytic activity. A hybrid binuclear-cobalt-phthalocyanine catalyst was investigated for greater power recovery from MFC [84]. Experiments were conducted for evaluating the effect of pyrolytic temperature from 300 °C to 1000 °C on the catalytic activity of binuclear-CoPc/C [85]. The pyrolytic temperature affects the ORR kinetics and the MFC having B-CoPc/C synthesized at 800 °C demonstrated the highest power density of 604 mW m−2 (vs. lowest of 280 mW m−2 from MFC with B-CoPc/C-300 °C). This power production was little lower in comparison to the power density of MFC having Pt/C (724 mW m−2 ). Cobalt oxide fusion on carbon support (C-CoOx /FePc/C, C-CoOx /CoPc/C) improved the ORR kinetics, and could manage to get 37% and 50% higher power output of 654 and 780 mW m−2 , respectively, as compared to the MFC having cathode doped with C-FePc and C-CoPc [38, 86]. Cathode having CoTMPP/FePcCNTs demonstrated high ORR and when used in MFC, it could achieve 50% higher power output (751 mW m−2 ) as compared to a platinum cathode based MFC [87].

3 Anode Materials The performance of a MFC is majorly affected by the bio-electrochemical activity on the anode. The anode is both structurally and functionally important as it hosts the bacterial cells and also acts as an electron sink for the metabolism of the substrate. Poor electrical output of anode in MFC greatly affects the performance of MFC and thus hinders its field-scale applicability [88]. Some of the most commonly used anode materials are graphite felt, graphite, graphite foil, tungsten carbide, activated graphite felt, carbon-cloth, activated carbon cloth, reticulated vitreous carbon, etc. All these materials are relatively stable, cheaper than platinum-based electrodes, and have

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high conductivity. However, their intrinsic hydrophobic character prohibits bacterial attachment resulting in higher charge transfer resistance and anodic fouling by microbial secretion adds onto the problem. Novel anode materials and modifications could enhance the performance of MFC by reducing activation overpotential losses and simultaneously increasing bacterial attachment, thus reducing the resistance encountered by the electrons during its transfer. Improper microbial attachment on the anode surface hinders the electron transfer mechanism between the electrogens and electrodes, thus diminishing the overall power production of MFC. This, in turn, works as a bottleneck in the field-scale applicability of MFCs. Ideally, anode materials should encourage biofilm formation, organic matter consumption, and extracellular electron transfer and also should be inexpensive [88]. Moreover, these materials should possess high electrical conductivity with low resistivity and higher specific surface area for bacterial attachment. The anode material should also be chemically inert exhibiting anti-corrosion and resist degradation along with apt mechanical strength and roughness [88]. The Pt and Pt black anodes outperforms carbon-based electrodes as graphite felt and carbon cloth but the high cost of Pt obstructs their applications in field-scale MFCs. Numerous anode materials like carbon nanotube, conducting polymers, graphene, stainless steel, and metal oxides are successfully used as anode modifications in MFCs.

3.1 Anode Modification Using Metal Oxides Carbon paper modified with TiO2 nano-sheets enhanced the power density of a MFC by 63% when compared to bare carbon paper as a bioanode. This improvement caused by the modified anode can be ascertained to the unique 3D open porous interface made of vertically oriented nano-sheets of TiO2 , which improved the mass transfer processes, electrochemical capacitance, biocompatibility, and specific surface area of the anode. As a result, the bacterial attachment was improved, and the movement of electrons was easier through direct pathways [89]. Current density as high as 0.22 ± 0.01 mA cm−2 was reported using Shewanella-attached carbon/hematite electrode, which was 6-folds higher than that of an MFC using unmodified carbon cloth electrode (0.036 ± 0.005 mA cm−2 ). The semi-conductive properties of iron oxides coupled with bacterial extracellular respiration played a vital role in improving the bio-current density of anode [90]. Use of 5.0% α-FeOOH on activated carbon anode demonstrated 36% increase in maximum power density (693 mW m−2 ) as compared to the activated carbon control anode (508 mW m−2 , [91]). The kinetics of extracellular electron transfer between bacteria and electrode is significantly enhanced by use of nano α-FeOOH, which in turn decreases the mass transfer losses on the surface of the anode [92]. The use of NiO nanoflakes/carbon cloth anode enhanced the power density of an MFC by three times to the bare carbon cloth [93]. This modification improved the interfacial electron transfer rate and bacterial adhesion due to the availability of more active reaction centres. The MFC having anode coated with MnO2 demonstrated

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highest power output of 3580 ± 130 mW m−2 , an increase of almost 25% as compared to MFC using unmodified carbon felt anode (2870 mW m−2 ) due to its inherent property of refining extracellular electron transfer mechanism and thus increasing the power output of the MFC [94].

3.2 Anode Modification Using Conductive Polymers Schröder et al. [95] reported shuttling of electrons from microbes to the anode by the use of polyaniline modified catalytically active anode having Pt black. Its application ensued increase in current density from 0.84 mA cm−2 to 1.45 mA cm−2 (polyaniline/Platinum black). A net improvement of 38% in power production was obtained by using polypyrrole coated carbon nanotube on carbon felt anode in comparison to plain carbon felt anode [96]. Such an enhancement can be credited to the increase in charge transfer from improved active surface area and higher contact angle between the bacterial cell adhesion and anode. Anodic modifications using poly (3, 4-ethylenedioxythiophene) enhanced the power output by 43% in comparison to the unmodified anode. The extensive porous structure of the material improved the availability of active sites and thus reducing the interfacial electron transfer resistance of the anode [97]. The use of the hydrogel carbon paper as anode increased current production and the maximum power density of MFC by 23% and 65%, respectively, in comparison with unmodified carbon paper owing to the reduction in the separation between the electrode and active sites of cytochrome enzymes present on the outer cell membrane of microorganisms [98].

3.3 Anode Modification Using Graphene and Carbon Nanotube Nanomaterials can be coated with graphene or carbon nanotubes and using it as the anode material can escalate the surface area and conductivity of the same thus, improving the electron transfer route [99]. Power density and energy conversion efficiency were improved by 2.7 and 3 folds, respectively, by graphene modification of carbon cloth anode in comparison to the bare carbon cloth anode [100]. Such an enhancement can be due to the high biocompatibility of graphene that encourages bacterial attachment on the anode thus creating more direct electron transfer activation centres and stimulating release of mediating molecules for enhanced electron transfer. Graphene has proved to be one of the best electrocatalysts by improving the performance of MFCs. However, the synthesis of graphene is complex. This not only adds to the overall fabrication cost of the MFC but also possess an ecological threat due to the use of hazardous chemicals during its production. Owing to the higher

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conductivity and environmental durability of conducting polymers, researchers are using them as anode materials in MFCs. These materials generally improve the bacterial attachment leading to higher current output. Cui et al. [101] reported anode performance when the polymers were doped with nanomaterial to form composites. The anode modifications generally introduce imperative functional groups on the anode encouraging exchanges between the functional groups on the electrode surface and bacterial cell wall. Though, further research efforts are required to improve the stability of functional groups on the anode which can endure the long-standing operation of MFC with simultaneous higher power production. Additionally, biocompatible and conductive polymers resulting from bacterial polyhydroxyalkanoates can modify the anode as they can easily be casted to the shape and sizes required for anode in MFCs.

4 Proton Exchange Membrane Membrane or separator acts as a physical boundary to avoid the hydraulic mixing of two chemically different fluids, i.e. anodic and cathodic electrolyte, which in turn would preserve the electrochemistry occurring at the two electrodes [102]. The anode and cathode electrode act as sites for thermodynamically driven oxidation and reduction reactions, which should be isolated so that the interspecies interaction in respective reactions is minimized. For instance, the cathode should ideally endorse ORR. However, the absence of a separator may not completely restrict the substrate crossover, which can interfere with the ORR. Hence, the separator would avoid the short-circuiting of two electrodes [103] and limit the overpotential losses to the minimum and allow the MFC to draw maximum voltage. In addition to the thermodynamic limitations in case of MFCs, proper attention should be given to the biotic microenvironment existing at the anode. Anaerobic conditions are necessary for the anodic chamber to maintain a conducive environment for proper sustenance of the microbial activity. The presence of oxygen can adversely affect the microbiology at the anode and alter the population dynamics [104]. The separator preserves the microbial population dynamics. Apart from the microbiota, the anodic chamber is the repository for the substrate, which is also the electron source. In order to derive maximum energy from the MFC, substrate loss should be minimized. The oxygen diffusion from the cathode side may result in the aerobic oxidation of the substrate in an anodic chamber, thereby abating the substrate available for voltage generation, since oxygen in the anodic chamber can compete with the solid anode electrode as the alternate terminal electron acceptor [105]. This diversion from the usual course can drain away the electrons and affect the current generation prospect. This presents another case in favour of using separators. In the absence of a separator, when substrate crossover takes place, there is every possibility that the cathode surface is contaminated with microorganisms and the active surface area available for catalytic activity is diminished. This, in turn, will reduce the performance of the cathode.

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4.1 Nafion and Its Modifications Perfluorosulfonic membranes (PSM), like Nafion, have been extensively used for investigations on MFCs. Nafion was developed by modifying a fluorinated polymer Teflon by introducing a pendant sulfonic acid group into the Teflon backbone [106]. Commercially, Nafion is available in different grades (Nafion 112, 115, 117, 1110) as per the thickness of the membrane, i.e., 2, 5, 7, 10 mil (1 mil = 25.4 μm), respectively. The structure of Nafion consists of a three-dimensional arrangement of hydrophobic tetrafluoride backbone with intermediate extensions of hydrophilic sulfonic acid terminal ends, both serving different objectives [107]. While the perfluoro backbone imparts chemical, mechanical, and thermal stability, the sulfonic acid terminal controls the proton transfer [108]. The proton transfer in Nafion is completely dependent on the hydration of the membrane. When the membrane is subjected to hydration, the sulfonic acid terminals interact with water, and small ionic clusters of water molecules are formed around the sulfonic acid groups [108], thereby creating a hydrophilic domain, which is discrete from the hydrophobic region. When the percolation threshold is attained, random networks of nano-channels connecting various hydrophilic acid/water clusters are formed. However, the water-filled clusters are small, and water molecules are mostly limited to the precincts of the ionic clusters. The accumulation of majority of water molecules in sulfonic acid solvation shells results in a high activation energy demand for proton transfer [106]. This high activation energy barrier does not allow the Grotthuss mechanism of proton transfer, i.e., protons hopping from the sulfonic acid groups to the nearby water molecules. This leaves opportunity only for proton transfer through diffusion. As the water uptake further increases and the larger hydrophilic domains are formed, which are better interconnected with wider hydrated channels. However, the strong electrostatic force of attraction between the multiple sulfonic acid terminals and the protonium ion is still stronger enough not to allow the Grotthuss mechanism of proton transfer [106]. The proton mobility by diffusion still dominates the proton conductivity of the membrane. Gradually with an increase in hydration, the availability of water molecules in the outer periphery of the ionic cluster increases and Grotthuss mechanism now dominates over the diffusion process for proton transfer. Under fully saturated conditions, the Nafion membrane resembles a densely interconnected network of percolation channels filled with free water molecules and nearly spherical water clusters, present at the interface of hydrophobic sulfonic acid groups surrounded by hydrophobic tetrafluoride backbone. At this instant, Nafion behaves like an aqueous electrolyte with analogous proton conductivity mediated by Grotthuss mechanism of proton transfer and attains a proton conductivity in the range of 0.09 S cm−1 , which is desirable for PEM in MFCs. This is how the proton transfer proceeds in case of Nafion membrane. Even though Nafion based membranes seem to be the best choice at the moment for MFCs, these membranes also suffer from issues like substrate and oxygen crossover, transport and accumulation of cations other than protons, susceptibility to biofouling

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and its high cost [109]. Further modifications in the PEM are essential to improve the membrane properties and its effective utilization in MFCs. Various strategies like adding fillers, coating, cross-linking, etc. are often undertaken to introduce desirable alterations in the pristine membrane-like Nafion [110–112]. However, the high cost of Nafion 117 (1659 $ m−2 ) is a major constraint in its field-scale application. Hence, it is advised to reduce the quantity of Nafion used in a membrane fabrication and substitute it by other polymers. Conducting polymers, like polyaniline (PANI) and polyvinylidene fluoride (PVDF), have the ability to improve the conductivity of polymer composite membranes, which is desirable in case of PEM used for MFC application. PANINafion composite membranes were prepared by impregnating Nafion-112 membrane with aniline, which subsequently polymerized to PANI within the Nafion matrix [113]. Nafion membranes were exposed to aniline for the different time duration (1, 2, 3, 4 h) to obtain composite membranes. The power performance of MFC incorporated with composite membranes increased with an increased proportion of PANI and MFC with Nafion/PANI demonstrated power output of 124 mW m−2 , around nine-folds higher than MFC with Nafion 112 membrane (13.98 mW m−2 ). The power output increased owing to improved proton transport across the composite membrane, which can be attributed to the formation of conjugate bonds of PANI with –SO3 groups present in Nafion [110]. However, when the PANI proportion was further increased, the surface area of the PANI per unit volume decreased, it adversely affected the PANI bonding with the sulphonic group of Nafion, which consequently decreased the power generated from the corresponding MFC. Still, the power output of MFC with Nafion/PANI was lower than MFC with Nafion 117. Similarly, PVDF at different concentration was incorporated to Nafion matrix using electrospinning techniques to prepare Nafion/PVDF nanofiber composite membrane. Membrane with PVDF and 0.4 g Nafion, when used in MFC, produced a highest power output of 4.9 mW m−2 as well as highest coulombic efficiency (CE) of 12.1% [111], which was less costly as compared to Nafion 117 owing to the use of PVDF fibre. This resultant power and CE were higher than MFC with Nafion membrane (4.25 mW m−2 , 9.8%). Pre-treatment of PVDF like dehydrofluorination with H2 SO4 doping, electrophilic substitution by sulphonation can reduce the hydrophobic properties of PVDF. After sulfonation, SPVDF was coated and laminated over Nafion 117 membrane, and the changes in membrane properties were evaluated. These modifications resulted in reducing the water uptake capacity and the cross-sectional transport of hydronium ions across the membrane. Moreover, the accessibility of sulfonic groups for proton exchange in Nafion membrane also reduced due to the PVDF coating. However, the constriction of water channels resulted in decreased oxygen transfer in coated and laminated membranes in comparison to the pristine Nafion membrane. When the membranes were incorporated in MFC, with Nafion membrane MFC demonstrated a power of 481.5 mW m−2 , around 7 and 14% higher than MFC with SPVDF coated (446.5 mW m−2 ) and laminated (413.8 mW m−2 ) Nafion, respectively. The overall higher performance of Nafion membrane can be attributed to the high proton conductivity, high polarity, and ion exchange capacity as compared to coated/laminated Nafion membranes.

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Atomic layer diffusion was employed on pristine Nafion membrane with trimethylaluminium as a precursor, and the properties of the Al2 O3 coated Nafion membrane were compared with the pristine Nafion membrane [112]. The Al2 O3 coating resulted in reducing the water uptake and conductivity of the membrane. Nonetheless the oxygen permeability and substrate crossover also reduced. The overall impact was positive as the MFC with Al2 O3 coated Nafion membrane demonstrated a power of 56.8 W m−3 , more than 2-folds increase over the Nafion integrated MFC (26.4 W m−3 ). Moreover, the Al2 O3 coating also imparted anti-biofouling properties that enhanced the longevity of the membrane when used in MFC. This can also be considered as a strategy to reduce the replacement time of membrane, which eventually reduces the operation and maintenance cost in the long run. Nano-alumina (Al2 O3 ) has also been employed as an inorganic filler material with poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP)/Nafion composite membrane [114]. The nano-alumina blend decreased the availability of the sulfonic groups present in Nafion for proton conduction; however, this parameter was compensated by the increased water uptake in the composite membrane due to the hygroscopic nature of nano-alumina. Hence, in case of A5 (5% replacement of Nafion by nano-alumina), the molecular level mixing of nano-alumina with polymer aided by increased water uptake resulted in higher proton conductivity as compared to pristine Nafion 115 membrane. The proton conductivity reduced in case of composite membranes with higher alumina content (10, 20%) despite the increased water uptake due to the increased agglomeration of Al2 O3 in the composite membrane. Further, with increasing alumina content, void space volume increased, thereby increasing the oxygen mass transfer coefficient. However, the oxygen diffusion coefficient for A5 was approximately 22% lower than Nafion 115. In consequence, MFC fitted with A5 membrane demonstrated a power of 541.5 mW m−2 , an improvement of around 11% in comparison to MFC with Nafion membrane [114]. Nafion/TiO2 nanocomposite (1% TiO2 loading) prepared with dimethylformamide (DMF) solvent has also been tested as a suitable membrane for MFC application [115]. The composite membrane revealed a uniformly porous morphology across its cross-section; whereas, Nafion 112 possessed a dense structure. The increased porosity of the composite membrane allowed higher water uptake. Additional hydroxyl groups are added to the surface of Nafion/TiO2 composite membrane as TiO2 is capable of oxidising water molecules to form Ti–OH group [116]. The presence of exchangeable hydroxyl groups along with increased water uptake facilitated the proton conduction via the Grotthuss and vehicular mechanism. The proton conductivity reported was 12.6 mS cm−1 , an elevation by three-folds over Nafion 112 membrane (proton conductivity = 4.2 mS cm−1 ). Under steady-state conditions, MFC with the composite membrane exhibited higher voltage output as compared to the Nafion incorporated MFC. Mesoporous silica (SBA-15) has also been used to cast composite membranes with Nafion followed by sulfonation at two different molar concentrations, i.e. 10% (SBA-SO3 H10) and 50% (SBA-SO3 H50) [117]. The MFC with SBA-SO3 H10 membrane exhibited 380 mW m−2 of power density, nearly three folds higher than the Nafion based MFC and two-folds higher than MFC with SBA-SO3 H50 membrane.

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The higher power output can be attributed to the respective microstructure of the composite membranes and the available alternate channels for proton conduction. The sulfonic groups in case of composite membranes are housed inside the silica mesopores, and hence, the chances of coordination leading to blockage of –SO3 H groups by cations present in the electrolyte is very less. However, in the case of SBASO3 H50, the sulfonic groups are moderately exposed to the surface as the silica is partially mesoporous and disordered. The cations can form coordination bonds with the exposed sulfonic groups, thus reducing the proton conductivity. This explains the relative decrease in power density among composite membranes with an increase in silica content. In addition, the sulfonated silica possesses a negative zeta potential and develop negative charge in contact with water. This generates an electrostatic repulsion force, which prevents the microbial adhesion to the membrane surface, thereby alleviating biofouling of membrane. Coating or lamination of Nafion with a mild hydrophobic polymer can be a useful strategy to reduce the mass transfer coefficient of the pristine Nafion membrane [118].

4.2 Non-Nafion Sulfonated Polymeric Membranes Considering the drawbacks of perfluorosulfonated membranes, the research focus shifted to membrane-based on fluorine-free hydrocarbon ionomer and partially fluorinated membranes. This led to the selection of a low-cost aromatic polyether ether ketone (PEEK) membrane owing to their ability to improve the inherent properties like thermal stability, mechanical strength, toughness, proton conductivity by controlling the degree of sulfonation [119]. Sulfonated polyether ether ketone (SPEEK) membrane demonstrated oxygen diffusion coefficient of one order of magnitude lower, and the proton conductivity of two order of magnitude lower than that of Nafion 117 [120]. The lower permeability of oxygen in the SPEEK membrane was due to the narrow gap between hydrophilic and hydrophobic parts. MFC having SPEEK membrane generated a power output of 670 mW m−2 , which is more than 2-folds higher than MFC having Nafion membrane [121]. Use of metal oxides like SiO2 , ZrO2 , TiO2, and Al2 O3 in composite membranes improve the proton conductivity and water retention properties [122]. When the metal oxides are further sulfonated, the metal oxide groups act as a vehicle for conduction of protons in addition to creating a path for proton transport. Composite SPEEK membrane prepared with 7.5% sulfonated silica, when used in MFC, delivered 1008 mW m−2 , more than three-folds higher than the MFC having Nafion 115 membrane [122]. The proton conductivity of the composite membrane increased with the percentage of sulfonated SiO2 from 2.5% to 7.5%. However, with a further increase to 10%, a drop in the proton conductivity values was noticed due to the overloading of sulfonated SiO2 and agglomeration of the particles in the SPEEK matrix. In comparison to casted membranes, the phase inverse type prepared membrane exhibit superior electrochemical and physical properties [123]. SPEEK membranes

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have also been blended with hydrophilic polymers like PVA nanofibers to promote their proton conductivity. Two different solvents, i.e., water and dimethylacetamide (DMAc), were used for dissolution of PVA/SPEEK membranes for casting. The MFC with PVA/SPEEK (water) demonstrated a power output of 722 mW m−2 as compared to 245 mW m−2 in MFC with PVA/SPEEK (DMAc) due to the lower membrane resistance offered by PVA/SPEEK (water) to the flow of protons [124]. Inorganic fillers like zeolites have a porous structure, which allows water molecules trapped in zeolite cage to favour the movement of protons through water-mediated proton transfer and in turn increase the conductivity of membranes [125]. The higher proton conductivity achieved in zeolite/SPEEK membrane allowed the corresponding MFC to achieve enhanced power and current density (176 mW m−2 , 500 mA m−2 ) as compared to MFC having Nafion (47.6 mW m−2 , 200 mA m−2 ,[126]). Moreover, the fabrication cost of the zeolite/SPEEK membrane was around 50% lower than Nafion 117. A phase inversion type membrane prepared with 7.5% STA and SPEEK when used in MFC, exhibited power of 207 mW m−2 , around five-folds higher than Nafion incorporate MFC (47 mW m−2 , [123]). This improvement was owing to the improved proton conductivity and lowered oxygen diffusion values recorded in the phase inversed membrane as compared to Nafion.

4.3 Polymeric Membranes The PVA is an easily available low-cost polymer, which exhibits low ionic resistance and antifouling property owing to its highly hydrophilic nature [127, 128]. Casted PVA separators with varying porosities induced by the action of a porogen (tetrabutylammonium chloride) have been used in air cathode MFCs to improve power and coulombic efficiency of MFCs [127]. While the development of biofilm on the cathode surface of membrane-less MFC (mMFC) increased charge transfer resistance and solution resistance, the proton conductivity in MFC-GF was hindered by the reduced porosity of the glass fibre membrane. This had a direct influence on the power production from respective MFCs, and MFC-5.6 (PVA membrane with 5.6% porogen) demonstrated output of 1232 mW m−2 , an improvement of around 10% and 26%, respectively, over the mMFC (1112 mW m−2 ) and MFC-GF (969 mW m−2 ). Similar trends were obtained for CE, where MFC-5.6 demonstrated 1.5-fold and twofold higher CE as compared to MFC-GF and mMFC, respectively. Power output from an MFC with PVA separator and activated carbon (AC) based cathode reduced only by 15% after 18 cycles of operation. The PVA membranes reduced the cathode deactivation by reducing the microbial growth on the cathode surface [128]. In addition to casting PVA separators, a simple method which involves spraying PVA directly on the cathode surface is also reported [129]. The MFC having cast PVA separators achieved power density of 942 mW m−2 , which was only 7% higher than MFC having a spray-on separator (873 mW m−2 ). The CE obtained for both the MFCs was comparable but the feed cycle time increased with the use of spray-on separator, which may be due to the better capability of the spray-on

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separator to avoid the oxygen intrusion into the anode chamber, thereby reducing the probability of aerobic substrate utilization. Electrode assembly with PVA based membrane has also been utilized in MFCs, where PVA thin films fabricated by freezing and thawing were pressed to the carbon cloth [130, 131]. The PVA has also been utilized to develop pore filled polyelectrolyte membrane, where PVA functions as a pore filler material for an etched polycarbonate porous substrate followed by further cross-linking with glutaraldehyde for varying time periods ranging from 24 to 96 h [132]. A cross-linking time of 72 h was found to be optimum for membrane fabrication, which when used in MFC showed long term stability and reported maximum power output of 110 mW cm−2 . The MFC having PVA-Nafion-borosilicate membrane produced a power output of 6.8 W m−3 , that is similar to MFC having only Nafion (7.1 W m−3 , [133]). However, the fabrication cost of PVA-Nafion-borosilicate membrane is around 11-folds lower than Nafion 117 membrane. PVA based membranes have been modified further in order to improve their performance in MFCs. A PVA based membrane was developed with the addition of graphene oxide (GO) and silicotungstic acid and used in a single chamber MFC [134]. The performance of the membrane was evaluated by varying the amount of GO from 0.3 wt% to 0.9 wt%. MFC with 0.5 wt% GO performed best among all fabricated membranes and achieved a maximum volumetric power output of 1.19 W m−3 . This power density was 26% more than MFC operated with Nafion membrane (0.88 W m−3 ). Glutaraldehyde, at different proportions, has also been added to vary the inherent membrane properties of PVA based membranes. The PVA with 4% glutaraldehyde resulted in optimum cross-linking and when used in MFC recorded a power density of 119 mW m−2 [135]. Heterocyclic, chemically stable, thermoplastic polymers, polybenzimidazole (PBI) also offer a cheaper alternative to Nafion [136]. They are easy to synthesize, and PBI polymers with varying degree of polymerization can be produced. Recently, different blend compositions of PBI with polyvinylpyrrolidone (PVP) were investigated as separators for single-chambered MFCs [137]. An MFC using a blend of 30:70 PBI/PVP membrane achieved a power density of 231.4 mW m−2 , which was around 81% higher than MFC with pristine PBI membrane owing to the improved polarity, ion exchange capacity and proton conductivity with the introduction of PVP to PBI. Another form in which PBI membrane was used in MFC is the sulfonated oxyPBI (S-OPBI). A substantial improvement of 61% in power density was observed in MFC incorporated with S-OPBI membrane (87.8 mW m−2 ) as compared to MFC with Nafion (54.5 mW m−2 ), owing to the faster proton transfer in water-filled nanochannels in case of S-OPBI membrane [138]. Poly-2,2’-(2,6-pyridine)-5,5’bibenzimidazole (py-PBI) was used as starting membrane material and further incorporated with mesoporous silica (SBA-15) and SBA-15 functionalized with different percentage of propylsulphonic groups (SBA-SO3 H10:10 mol % and SBA-SO3 H50: 50 mol %) [109]. Py-PBI/SBA-SO3 H10 membrane incorporated MFC showed the most stable performance in terms of power density (1300 mW m−2 ) over 100-days period as a substantial fraction of the sulphonic groups are housed inside the silica

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mesopores, which allows additional pathways to the protons for migration. Even Py-PBI and Py-PBI/SBA-SO3 H50 incorporated MFC demonstrated overall stable performance with only 29% and 18% decrease in power, respectively.

4.4 Clayware Membranes The fabrication cost of MFCs can be reduced if the membrane is strong enough to bear the hydraulic load and can function as the structural material for the anode chamber. Moreover, one of the major drawbacks of using an ion-selective membrane in MFC is the accumulation of cationic or anionic species, which leads to pH imbalance and results in the drop in pH of electrolyte in the anodic chamber. This may adversely affect the activity of electrogenic bacteria and results in a decrease in the power output. This issue is not observed in case of ceramic membranes, which carry on proton transfer across the membranes as a consequence of the porosity of the clay, thereby avoiding any instances of anodic acidification [139]. Due to the porous nature of clay, abundant interstitial voids are present in their structure, which allows them to retain water between adjacent clay layers. The water participates in the formation of pseudo hydrogen bonding with the Si+4 , Ca+2 , Al+3 besides the out bound OH− ions. This leads to a process commonly known as the grotthous mechanism, where an array of intermittent hydrogen bonds, i.e., H3 O+ , H5 O2 + , H7 O3 + is formed, and the proton migrates from one end to another. The ceramic membranes, in comparison to the polymeric membranes possess superior physical integrity, thermal stability, and chemical resistance, which make them appropriate to deal with wastewater having different pH range. In addition, they can be subjected to acid or alkaline washing or physical cleaning to remove the biofouling growth on the surface of the membrane. This makes them appropriate for extreme cleaning conditions, including alkaline and acid washing as well as physical cleaning methods as already reported ceramic membrane used for filtration [140]. Various MFC studies make use of cylindrical clayware and clayware plate (Fig. 2), which simultaneously perform as the anodic chamber and wall material itself as a proton exchange material [17, 29, 141–145]. It was found that thinner clayware separator of the thickness of 3 mm performed better than comparably thicker separator of 8.5 mm [144]. Based on their distinct structures and chemical compositions, different clay minerals like montmorillonite, kaolinite, and illite possess a different range of exchange capacities [146]. Introduction of these minerals can facilitate faster proton conduction due to the higher number of available cation exchangeable sites and improved conductivity. In addition, the interstitial void space is also reduced, which can help in reducing the oxygen diffusion across the anodic and cathodic chambers [147]. The MFCs having clayware separator comprising of the highest percentage of montmorillonite (20% w/w) demonstrated power output of 7.55 W m−3 , around 48% higher than the control MFC (3.95 W m−3 ) having clayware separator without any cationic exchanger [148]. Whereas, MFC with clayware separator having kaolinite (20% w/w) generated comparatively lower power (5.51 W m−3 ), due to lower cation

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Fig. 2 Different shapes of clayware separators a Plate shaped b Cylinder shaped

exchange capacity of kaolinite (15–20 meq/100 g) as compared to montmorillonite (80–150 meq/100 g, [123]. Low-cost ceramic MFCs can offer a green and sustainable approach for providing decentralized sanitation in remote rural areas, which have limited facilities in regard to electrical grids sanitation systems. Moreover, the ceramic material is free from the addition of any hazardous chemical and reduces dependency on the petrochemical industry for deriving synthetic polymers.

5 Alternative to High-Cost Terminal Electron Acceptors In an MFC, the cathode acts as a sink for receiving the two useful by-products of substrate oxidation from the anodic half-cell, i.e., the electrons via the external resistance and the protons which migrate across the proton exchange membrane. The use of a terminal electron acceptor (TEA) during the cathodic half-cell reaction in MFC is paramount in order to accept the electrons and complement the proton migration, thus completing the reduction reaction [149]. The choice of TEA is an important consideration as its redox potential directly governs the overall cell potential. In addition to the energy considerations, availability, sustainability, the nature of final products emerging from the reduction reaction and the cost-effectiveness are some of the factors, which should be taken into account prior to selecting the appropriate compound as TEA [150]. Some of the earliest studies reported the use of ferricyanide as TEA in MFCs [151–154]. When ferricyanide was used as the sole electron acceptor, power obtained from MFC was 50–80% higher than that demonstrated by a MFC having dissolved oxygen as TEA [155]. Further, an MFC recorded a power output of 3.6 W m−2 when catholyte enriched with ferricyanide was subjected to continuous aeration [154]. In a similar MFC configuration, ferricyanide helped in achieving a higher output of 0.79 mW, as compared to MFC having oxygen aerated cathode (0.16 mW, [80]).

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Permanganate emerged as a superior alternative to ferricyanide owing to its higher reduction potential. Permanganate was almost five times more effective in enhancing power in MFCs as compared to ferricyanide [156]. Similar results were reported by Pandit et al. [157], where permanganate was found to be a better electron acceptor than ferricyanide in MFC using anion exchange membrane. Noticeably, the power production decreases with depletion of electron acceptors in the electrolyte, hence the cathode chamber needs to be continuously supplemented with fresh catholyte. Therefore, the use of chemical catholyte was discouraged, owing to the additional cost associated with their regular replacement [158]. However, treating industrial effluents having hexavalent chromium in cathodic chamber of MFCs supplemented the need of fresh catholyte in MFCs, while taking care of the cost aspect. A preliminary study on cathodic reduction of Cr(VI) demonstrated a maximum power of 453 mW m−2 at 10 mM initial Cr(VI) concentration [159]. Light radiated natural rutile coated graphite cathode illustrated higher Cr(VI) reduction kinetics (1.6 times faster) as well as cathode potential (0.80 V vs 0.55 V) in comparison to dark conditions [160]. A dual-chambered MFC achieved 99.5% Cr(VI) removal and generated power of 1.6 W m−2 while treating electroplating industry wastewater in the cathodic chamber [161]. Novel transition metals-dispersed carbon nanofiber-based cathode demonstrated a significantly high power output as well as Cr(VI) reduction rate of 1.54 W m−2 and 2.13 g-Cr(VI) m−3 h, respectively [25]. It is to be noted that chromate reduction and subsequent power generation is a pH-dependent process, where higher power output is demonstrated at lower pH. However, this leads to migration of protons and Cr(VI) ions from cathodic chamber to anodic chamber across the PEM owing to the concentration gradient, which can adversely affect the anodic culture and eventually the power generation [162]. A solution to this problem was provided by the use of bipolar membranes; wherein, the improved power output of 150.2 mW m−2 , in comparison to PEM-MFC (45.2 mW m−2 ), was achieved while utilizing 50% of electroplating industry wastewater [162]. Furthermore, if the MFC can be operated at neutral pH without affecting the power production, it would be a more feasible concept for scaling up operations. However, chromium reduction on cathodes at alkaline pH was facilitated when chelating agents like lactate were used [163]. Still, the cost associated with pH balance can be a hurdle for its large-scale implementation. A polypyrrole/AQS (9,10-anthraquinone2-sulfonic acid sodium salt) coated cathode aided the MFC to garner 299.6 mWm−2 utilizing Cr(VI) reduction reaction at neutral pH. However, the poor durability of the modified cathode for multiple cycles limits its long-term application. Introduction of biocathodes revealed new possibilities for treating Cr(VI) wastewater and subsequent energy production. Though the idea was successfully demonstrated [139, 140], the power output was low (Table 2). Power output improved when MFC with biocathodes was either operated at a predetermined set potential [164] or supplemented with carbon sources like fumarate and lactate [165, 166]. However, chromium-containing wastewater, when used in biotic cathodes elevates the operation cost due to the additional requirement of neutralizing the catholyte to support the inhabiting microbiota.

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Table 2 Various terminal electron acceptors and corresponding power density achieved in MFCs Electron acceptor Chemical reaction Fe(CN)3− 6

− Fe(CN)3− 6 + e →

E° (V)

Maximum power density References W m−2

0.36

0.17 W

[155]

4.31

[151]

3.99

[156]

0.12

[157]

0.45

[159]

6.40*

[164]

2.40*

[183]

0.048

[157]

0.056

[184]

0.435

[159]

1.03

[185]

Fe(CN)4− 6 KMnO− 4

Cr2 O2− 7

MnO− 4 MnO2

3e−

+ + + 2H2 O

− Cr2 O2− 7 + 6e + 3+ 2Cr + 7H2 O

4H+

14H+

→

1.70

→ 1.33

1.60

[161]

0.00172

[165]

1.54

[25]

0.021

[163]

0.00059 Cu+2

Cu+2 + 2e− → Cu

0.286 0.80 0.14 W

[169]

0.338*

[170]

6.50*

[172]

2.00 Ag(NH3 )2

Ag(NH3 )2 + e− → Ag + 2NH3

AuCl− 4

− AuCl− 4 + 3e → − Au + 3Cl

Ag+

Ag+ + e− → Ag

VO+ 2

*W

m−3

+ VO+ 2 + 2H + 2+ VO + H2 O

e−

0.373 0.317 6.58

→

[166] [167]

[171] [179] [181]

0.799 0.109

[176]

8.26*

[178]

1.93

[180]

4.25

[177]

0.991 0.62

[185]

0.53

[175]

0.57

[173]

0.55

[174]

0.419

[26]

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The ability of cathode of MFC to reduce metal ions present in wastewater to their lower oxidation states is undoubtedly a future prospect in the field of wastewater treatment. A further impetus in the direction of using metal-containing ions as TEA for higher power generation in MFCs was provided by the added incentive of removing or recovering toxic metals like Cu(II) and Fe(III) from water on the cathode of MFC [160, 161, 167, 168]. When Cu(II) reduction took place via cathodic reaction under aeration, the MFC with a bipolar membrane generated 0.8 W m−2 power, around 30-folds higher than the MFC using oxygen as TEA [168]. A glucose fed MFC, when operated at very low external resistance (< 5 ), evidenced increase in power with an increase in initial Cu(II) in catholyte, and eventually demonstrated a power output of 339 mW m−3 and a Cu(II) removal efficiency of > 99% at an initial Cu(II) concentration of 6412.5 mg L−1 [169]. At the electrode separation distance of 25 cm, a pilot-scale MFC demonstrated a power of 0.14 W and 100% Cu(II) removal; however, both power and Cu(II) removal efficiency decreased with increasing electrode distance [170]. Optimizing the operational parameters of the MFC, i.e. anodic: cathodic chamber volume (1:2) and external resistance (200 ) resulted in enhanced power of 2 W m−2 , which was 6 to 22 times higher than previous studies [171]. Stainless steel (SS) cathode was found to be more suitable cathode material as compared to carbon rod and titanium sheet for simultaneous power generation and Cu(II) removal [172]. MFC with SS cathode demonstrated a power output of 6.5 W m−3 when Cu(II) removal of 99.7% was achieved. Since the reduction potential of Cu(II) was very low as compared to oxygen; the power enhancement is secondary where the primary objective deals with metal remediation in wastewater. Vanadium is a superior choice to copper for TEA owing to its relatively higher reduction potential. A MFC study where V(V) removal was carried out in both anodic and cathodic chambers indicated that maximum power density (419 mW m−2 ) increased majorly due to the contribution of cathode potential at 150 mg L−1 V(V) in catholyte [26]. Simultaneous removal of sulphide in the anodic chamber and vanadium in the cathodic compartment of a dual-chambered MFC generated a power output of 572 mW m−2 [173]. Still, the V(V) was exhausted at the end of a cycle to V(IV), and the reaction ceased. However, the idea of regenerating the already reduced V(IV) back to its higher oxidation species V(V) by external aeration in the cathodic chamber was a novel approach, which enhanced the power output by nearly 40% to attain an output of 553 mW m−2 [174]. Again, vanadium as an electron acceptor was more efficient at low pH, which implies that the increase in pH will directly affect the MFC’s performance. Therefore, biocathodes were employed in an MFC to reduce vanadium at neutral pH and in turn, enhance the power output [175]. The biocathodes successfully achieved 200 mg L−1 V(V) removal in 7 days and demonstrated a power output of 529 mW m−2 , nearly 10% higher than MFC with abiotic cathode (478 mW m−2 ). The possibilities of recovering precious metals of higher economic values like Au and Ag from their corresponding wastewater and in the process to enhance the energy recovery from MFCs has also been explored. Power recovery from MFC having Ag+

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as electron acceptor was 109 mW m−2 , which was more than three times in comparison to MFC having AgS2 O3 − as an electron acceptor, whereas both MFCs removed up to 95% of Ag [176]. Electricity generation was found to be directly proportional to the inherent Ag+ concentration (50–1000 ppm) in the catholyte, and the MFC demonstrated 4.25 W m−2 for Ag+ concentration of 1000 mg L−1 [177]. Similar results were reported by Ho et al. [178], where a power output of 8.26 W m−3 was observed at a concentration of 1000 mg L−1 , which eventually decreased to 5.4 W m−3 when Ag+ concentration was further increased to 2000 mg L−1 . When alkaline pH was maintained for silver recovery from ammonia chelated silver wastewater, MFC generated power output of 0.317 W m−2 with 99.9% silver deposition on the cathode [179]. Furthermore, Ag+ ions enhanced the cathode potential and decreased the internal resistance of a dual-chambered MFC ensuing a maximum power output of 1.93 W m−2 at initial Ag(I) concentration of 2000 ppm in the catholyte [180]. The tetrachloroaurate ion (AuCl4 − ) present in various electronic waste is also a potential electron acceptor, which has been found to enhance the power density of MFC to 6.58 W m−2 when used in cathodic chamber at 2000 mg L−1 [181]. Despite the value addition, the diffusion of the Ag+ ions to the anodic chamber is a risk associated with this process. The continuous exposure of Ag+ to the anodic microbiota can adversely affect the power output of the MFCs. Similarly, the feasibility of denitrification in the cathodic chamber of MFC, i.e., when NO3 – is reduced to NO2 – and eventually to N2 also aided the cathode potential. This concept was taken a step further by achieving simultaneous degradation of sulphide and nitrate in anodic and cathodic chambers of an MFC. In this case, sulphide behaved as anodic electron acceptor, while nitrate performed the role of cathodic electron acceptor, eventually achieving a power output of 2.80 W m−3 [182]. Despite the use of various electron acceptors till date, oxygen is by far the most promising option considering that it is abundantly available in nature, which makes it sustainable as well as cost effective [186]. Moreover, the standard reduction potential of oxygen (1.229 V versus SHE) is comparatively higher than most of the TEA reported in various studies (Table 2). Most reactions involving chemical TEAs are pH dependent, and disposal of exhausted TEA is again a problem. Further, the eventual reduction of oxygen on the cathode yields water, which is a highly desirable end product. All these attributes are indispensable for establishing large scale MFC units in future for wastewater treatment. Hence, sincere efforts should be undertaken to understand the basics of cathodic reduction of oxygen, also known as the ORR.

6 Perspectives and Way Forward MFCs are projected as future technology for energy efficient wastewater treatment. Hence, it is necessary that the materials and composites used for fabrication of various components like a membrane, electrode catalyst, etc. are easy to synthesize, stable in real wastewater, environment friendly and low-cost. Currently, MFC is still in a laboratory development phase. However, it has immense potential to be the leading

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technology, which can generate green and clean source of energy from organic matter present in wastewater. Further research should focus on increasing the scope of pollutants, which can be treated in the MFC, like aromatic hydrocarbons, pharmaceuticals, xenobiotics, etc., and integrating MFCs with other wastewater treatment processes [187]. The architecture of the MFC, the size of the units, and the materials used for fabrication of various components of MFC are the major areas of research, which will decide the future course of this technology [188]. The architecture of MFC and their size of each unit have an important role to play for reducing concentration losses; whereas, the materials used for catalyst and membrane can help in overcoming the ohmic losses occurring in MFC. Air cathode MFCs, owing to their simple deign and cost efficiency, are the preferred option to aqueous cathode MFCs when scaling-up is considered. However, restricting the substrate diffusion across the membrane still remains an issue which needs to be addressed. The shift in focus of research for cathode catalyst toward non-platinum catalysts is a welcome attribute to find new avenues in ORR electrocatalyst [189–191]. Significant progress has been made with regard to the transition metal based catalyst, which has demonstrated comparable performance to Pt-based cathode catalyst in laboratory scale. It will be a challenge to replicate the same performance in field-scale, and further efforts are required to ensure the durability of the electrocatalyst and achieve sustainable stable performance of MFC. Moreover, the dual use of ceramic separators as membrane and anodic chamber and its ability to withstand hydrostatic pressure, thermal and pH shocks is a welcome prospect which can have long lasting contribution in developing low-cost wastewater treatment system and shall be explored for onsite sanitation. Utilization of sulfonated co-poly(ether imide) membranes [192, 193], and incorporation of conductive minerals can improve the ionic conductivity and reduce the ohmic resistance offered by the membranes. The utilization of wastewater containing metal ions as catholyte can enhance the power generation from MFCs owing to their higher reduction potential and the cost incurred for the supply of chemical catholytes can also be avoided. Hence, not only the properties of materials used but also the cost of each component will decide the practical implementation of MFC for real wastewater treatment. Finally, incorporation of the power management system and supercapacitors in order to harvest and store energy from the MFC for use in practical purposes can provide the impetus for real field application of this multifunctional technology.

7 Conclusion MFCs are the recent addition to the group of future upcoming technologies, which have the potential to address the impending climate change scenario by alleviating pollution. Moreover, they could also serve as a solution to the rapidly depleting fossil fuel reserves by harvesting direct electricity from oxidizable wastes while remediating them. In order to deliver potential benefits, the upscaling of this technology is a

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must. However, the path to MFC upscaling is deterred by the inherent overpotential losses, which hinder the accomplishment of maximum achievable voltage. Nevertheless, the increasing awareness about the technology has contributed in large terms to the intense research in material science in pursuit of more materials to supplement electrodes and membranes in MFC to overcome the losses. Electrodes need to be reformed with the introduction of alloys that are bimetallic, trimetallic, organometallic, etc. to improve the electrochemical reactions. Similarly, biocompatibility should also be a critical factor while selecting materials as microorganisms are the principal drivers of this whole electron process. As the long-term sustenance of this technology is crucial, hence the materials selected should be durable also. It will be a better proposition if the waste materials can be utilized as resource for MFC components such as metal laden waste streams as source of catholytes, junk metals as source of electrodes/catalyst, etc. so that this technology can further be established as eco-friendly solution. MFC has far more potential than to serve as an alternate source of energy, which needs to be explored in future times. The added benefit of waste treatment in addition to power generation has found multiple buyers and believers of this technology. Further, as much as possible, eco-friendly methods such as green synthesis protocol for materials required for fabrication should be adopted. In the subsequent years, we can expect a significant increase in MFC based research, to take this technology a step ahead toward commercialization. Acknowledgements The research work was financially supported by Department of Biotechnology, Government of India (BT/IN/INNO-INDIGO/28/MMG/2015-16).

References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

Potter, M. C. (1911). Proceedings of the Royal Society B: Biological Sciences, 84, 260. Cohen, B. (1931). Journal of Bacteriology, 21, 18. Canfield, J. H., Goldner, B. H., Lutwack, R. (1963). Magna Corp. Anaheim, CA 63. Du, Z., Li, H., & Gu, T. (2007). Biotechnology Advances, 25, 464. Rinaldi, A., Mecheri, B., Garavaglia, V., Licoccia, S., Nardo, D., & Traversa, E. (2008). 417. Rismani-Yazdi, H., Carver, S. M., Christy, A. D., & Tuovinen, O. H. (2008). Journal of Power Sources, 180, 683. Kim, S., Chae, K. J., Choi, M. J., & Verstraete, W. (2011). Environmental Engineering Research. Bard, A. J., & Faulkner, L. R. (2001). Wiley. Vaszilcsin, N., & Neme¸s, M. (2009). Introduction to Electrochemistry by Problems (Politehnica). Girguis, P. R., Nielsen, M. E., Reimers, C. E. (2010). Ben, K., Ramli, W., Daud, W., & Ghasemi, M. (2014). International Journal of Hydrogen Energy, 39, 4870. Allen, R. M., & Bennetto, H. P. (1993). Applied Biochemistry and Biotechnology, 39, 27. Logan, B. E. (2004). Environmental Science and Technology, 38, 160. Fan, Y., Sharbrough, E., & Liu, H. (2008). Environmental Science and Technology, 42, 8101. Zhang, Q., Hu, J., Lee, D. (2016). 217, 121. Aelterman, P., Rabaey, K., Clauwaert, P., & Verstraete, E. (2006). 9.

Development of Low-Cost Microbial Fuel Cell …

193

17. Behera, M., Jana, P. S., More, T. T., & Ghangrekar, M. M. (2010). Bioelectrochemistry, 79, 228. 18. Mansoorian, H. J., Mahvi, A. H., Jafari, A. J., Amin, M. M., Rajabizadeh, A., & Khanjani, N. (2013). Enzyme and Microbial Technology. 19. Mansoorian, H. J., Mahvi, A. H., Jafari, A. J., & Khanjani, N. (2016). Journal of Saudi Chemical Societ. 20. Tiwari, B. R., Noori, M. T., & Ghangrekar, M. M. (2018). MRS Advances, 3, 657. 21. Kalathil, S., Lee, J., & Cho, M. H. (2012). Bioresource Technology. 22. Feng, Y., Wang, X., Logan, B. E., & Lee, H. (2008). Applied Microbiology and Biotechnology, 78, 873. 23. Wen, Q., Kong, F., Zheng, H., Cao, D., Ren, Y., & Yin, J. (2011). Chemical Engineering Journal, 168, 572. 24. Morris, J. M., Jin, S., Crimi, B., & Pruden, A. (2009). Chemical Engineering Journal. 25. Gupta, S., Yadav, A., & Verma, N. (2017). Chemical Engineering Journal, 307, 729. 26. Zhang, B., Tian, C., Liu, Y., Hao, L., Liu, Y., Feng, C., Liu, Y., & Wang, Z. (2015). Bioresource Technology, 179, 91. 27. Liu, S., Li, L., Li, H., Wang, H., & Yang, P. (2017). Bioresource Technology, 243, 1087. 28. Zhang, B., Zhao, H., Zhou, S., Shi, C., Wang, C., & Ni, J. (2009). Bioresource Technology, 100, 5687. 29. Ghosh Ray, S., & Ghangrekar, M. M. (2015). Bioresource Technology, 176, 8. 30. Su, L., Fan, X., Yin, T., Chen, H., Lin, X., Yuan, C., & Fu, D. (2015). RSC Advances. 31. Liu, X. W., Wang, Y. P., Huang, Y. X., Sun, X. F., Sheng, G. P., Zeng, R. J., Li, F., Dong, F., Wang, S. G., Tong, Z. H., & Yu, H. Q. (2011). Biotechnology and Bioengineering, 108, 1260. 32. Gajaraj, S., & Hu, Z. (2014). Chemosphere, 117, 151. 33. Wang, Y. P., Liu, X. W., Li, W. W., Li, F., Wang, Y. K., Sheng, G. P., Zeng, R. J., & Yu, H. Q. (2012). Applied Energy, 98, 230. 34. Liu, J., Liu, L., Gao, B., & Yang, F. (2013). J. Memb. Sci., 430, 196. 35. Wang, Y. P., Zhang, H. L., Li, W. W., Liu, X. W., Sheng, G. P., & Yu, H. Q. (2014). Biochemical Engineering Journal, 85, 15. 36. Anupama, S., Pradeep, N. V., & Hampannavar, U. S. (2013). Sugar Tech, 15, 197. 37. Ghasemi, M., Daud, W. R. W., Hassan, S. H. A., Oh, S.-E., Ismail, M., Rahimnejad, M., & Jahim, J. M. (2013). Journal of Alloys and Compounds, 580, 245. 38. Ahmed, J., Yuan, Y., Zhou, L., & Kim, S. (2012). Journal of Power Sources, 208, 170. 39. Shi, X., Feng, Y., Wang, X., Lee, H., Liu, J., Qu, Y., He, W., Kumar, S. M. S., & Ren, N. (2012). Bioresource Technology. 40. Zhang, F., Saito, T., Cheng, S., Hickner, M. A., & Logan, B. E. (2010). Environmental Science and Technology. 41. Zhang, F., Cheng, S., Pant, D., Van Bogaert, G., & Logan, B. E. (2009). Electrochemistry Communications, 11, 2177. 42. Zhang, F., Merrill, M. D., Tokash, J. C., Saito, T., Cheng, S., Hickner, M. A., & Logan, B. E. (2011). Journal of Power Sources, 196, 1097. 43. Ben Liew, K., Daud, W. R. W., Ghasemi, M., Leong, J. X., Su Lim, S., & Ismail, M. (2014). International Journal of Hydrogen Energy, 39, 4870. 44. Noori, M. T., Mukherjee, C. K., & Ghangrekar, M. M. (2017). Electrochimica Acta, 228, 513. 45. Noori, M. T., Ghangrekar, M. M., & Mukherjee, C. K. (2016). International Journal of Hydrogen Energy, 41, 3638. 46. Wang, Z., Cao, C., Zheng, Y., Chen, S., & Zhao, F. (2014). ChemElectroChem, 1, 1813. 47. Tsai, H.-Y., Wu, C.-C., Lee, C.-Y., & Shih, E. P. (2009). Journal of Power Sources, 194, 199. 48. Ge, D., Yang, L., Fan, L., Zhang, C., Xiao, X., Gogotsi, Y., & Yang, S. (2015). Nano Energy, 11, 568. 49. Gong, K., Du, F., Xia, Z., Durstock, M., & Dai, L. (2009). Science (80-. )., 323, 760 LP. 50. Duteanu, N., Erable, B., Senthil Kumar, S. M., Ghangrekar, M. M., & Scott, K. (2010). Bioresource Technology.

194

M. M. Ghangrekar and B. R. Tiwari

51. Luo, Z., Lim, S., Tian, Z., Shang, J., Lai, L., MacDonald, B., Fu, C., Shen, Z., Yu, T., & Lin, J. (2011). Journal of Materials Chemistry. 52. Poizot, P., Laruelle, S., Grugeon, S., Dupont, L., & Tarascon, J. M. (2000). Nature, 407, 496. 53. Bag, S., Roy, K., Gopinath, C. S., & Raj, C. R. (2014). ACS Applied Materials and Interfaces, 6, 2692. 54. Xia, W.-Y., Tan, L., Li, N., Li, J.-C., & Lai, S.-H. (2017). Journal of Materials Science, 52, 7539. 55. Song, T. S., Bin Wang, D., Wang, H., Li, X., Liang, Y., & Xie, J. (2015). International Journal of Hydrogen Energy. 56. Mecheri, B., Iannaci, A., D’Epifanio, A., Mauri, A., & Licoccia, S. (2016). ChemPlusChem, 81, 80. 57. Zhang, X., Li, K., Yan, P., Liu, Z., & Pu, L. (2015). Bioresource Technology, 187, 299. 58. Liang, J., Jiao, Y., Jaroniec, M., & Qiao, S. Z. (2012). Angewandte Chemie International Edition. 59. Ben Liew, K., Daud, W. R. W., Ghasemi, M., Loh, K. S., Ismail, M., Lim, S. S., Leong, J. X. (2015). International Journal of Hydrogen Energy, 40, 11625. 60. Farahani, F. S., D’Epifanio, A., Majidi, M. R., Placidi, E., Arciprete, F., & Mecheri, B. (2020). Journal of Nanoparticle Research, 268, 116487. 61. Ayyaru, S., Mahalingam, S., & Ahn, Y. H. (2019). International Journal of Hydrogen Energy, 44, 10. 62. Khajeh, R. T., Aber, S., & Nofouzi, K. (2020). Materials Chemistry and Physics, 240, 122208. 63. Ren, C., Li, K., Lv, C., Zhao, Y., Wang, J., Guo, S. (2019). Journal of Electroanalytical Chemistry, 840. 64. Ortiz-Martínez, V. M., Touati, K., Salar-García, M. J., Hernández-Fernández, F. J., de los Ríos, A. P. (2019). Biochemical Engineering Journal, 151, 107310. 65. Jiang, L., Chen, J., Han, D., Chang, S., Yang, R., An, Y., Liu, Y., Chen, F. (2017). Journal of Power Sources, 453, 227877. 66. Choi, Y. J., Mohamed, H. O., Park, S. G., Mayyahi, R. B. A., Dhaifallah, M. A., Rezk, H., Ren, X., Yu, H., & Chae, K. J. (2020). International Journal of Hydrogen Energy, 45, 10. 67. Dai, Y., Li, H., Wang, Y., Zhong, K., Zhang, H., Yu, J., Huang, Z., Yan, J., Huang, L., Liu, X., Lu, Y., Xu, T., Su, M. (2021). Journal of Power Sources, 229498. https://doi.org/10.1016/ j.jpowsour.2021.229498. 68. Huang, Q., Zhou, P., Yang, H., Zhu, L., & Wu, H. (2017). Chemical Engineering Journal, 325, 466. 69. Liu, D., Mo, X., Li, K., Liu, Y., Wang, J., & Yang, T. (2017). Journal of Power Sources, 359, 355. 70. Jasinski, R. (1964). Nature. 71. Baranton, S., Coutanceau, C., Roux, C., Hahn, F., & Léger, J. M. (2005). Journal of Electroanalytical Chemistry. 72. Zhao, F., Harnisch, F., Schröder, U., Scholz, F., Bogdanoff, P., & Herrmann, I. (2005). Electrochemistry Communications, 7, 1405. 73. Jasinski, R. (2007). Journal of the Electrochemical Society. 74. Bellabarba, R. M. (2015). Johnson Matthey Technology Review. 75. Gojkovi´c, S. L., Gupta, S., & Savinell, R. F. (1999). Journal of Electroanalytical Chemistry. 76. Birry, L., Mehta, P., Jaouen, F., Dodelet, J. P., Guiot, S. R., & Tartakovsky, B. (2011). Electrochimica Acta. 77. Burkitt, R., Whiffen, T. R., & Yu, E. H. (2016). Applied Catalysis B: Environmental, 181, 279. 78. Yuan, Y., Zhao, B., Jeon, Y., Zhong, S., Zhou, S., & Kim, S. (2011). Bioresource Technology, 102, 5849. 79. Van Der Putten, A., Elzing, A., Visscher, W., & Barendrecht, E. (1986). Journal of Electroanalytical Chemistry. 80. Zagal, J. H. (1992). Coordination Chemistry Reviews, 119, 89.

Development of Low-Cost Microbial Fuel Cell …

195

81. Yu, E. H., Cheng, S., Logan, B. E., & Scott, K. (2009). Journal of Appled Electrochemistry, 39, 705. 82. Kim, J. R., Kim, J. Y., Han, S. B., Park, K. W., Saratale, G. D., & Oh, S. E. (2011). Bioresource Technology, 102, 342. 83. Cheng, S., Liu, H., & Logan, B. E. (2006). Environmental Science and Technology, 40, 364. 84. Li, B., Zhou, X., Wang, X., Liu, B., & Li, B. (2014). Journal of Power Sources, 272, 320. 85. Li, B., Wang, M., Zhou, X., Wang, X., Liu, B., & Li, B. (2015). Bioresource Technology, 193, 545. 86. Ahmed, J., Kim, H. J., & Kim, S. (2014). RSC Advances, 4, 44065. 87. Deng, L., Zhou, M., Liu, C., Liu, L., Liu, C., & Dong, S. (2010). Talanta. 88. Hindatu, Y., Annuar, M. S. M., & Gumel, A. M. (2017). Renewable and Sustainable Energy Reviews, 73, 236. 89. Yin, T., Lin, Z., Su, L., Yuan, C., & Fu, D. (2014). ACS Applied Materials and Interfaces, 7, 400. 90. Zhou, S., Tang, J., & Yuan, Y. (2015). Bioelectrochemistry. 91. Peng, X., Yu, H., Wang, X., Gao, N., Geng, L., & Ai, L. (2013). Journal of Power Sources, 223, 94. 92. Jadhav, D. A., Ghadge, A. N., & Ghangrekar, M. M. (2015). Bioresource Technology, 191, 110. 93. Qiao, Y., Wu, X. S., & Li, C. M. (2014). Journal of Power Sources. 94. Zhang, C., Liang, P., Jiang, Y. & Huang, X. (2015). Journal of Power Sources. 95. Schröder, U., Nießen, J., Scholz, F. (2003). Angewandte Chemie International Edition. 96. Roh, S.-H., & Woo, H.-G. (2014). Journal of Nanoscience and Nanotechnology. 97. Liu, X., Wu, W., & Gu, Z. (2015). Journal of Power Sources. 98. Liu, X. W., Huang, Y. X., Sun, X. F., Sheng, G. P., Zhao, F., Wang, S. G., & Yu, H. Q. (2014). ACS Applied Materials and Interfaces. 99. Mehdinia, A., Ziaei, E., & Jabbari, A. (2014). Electrochimica Acta,. 100. Liu, J., Qiao, Y., Guo, C. X., Lim, S., Song, H., & Li, C. M. (2012). Bioresource Technology. 101. Cui, H. F., Du, L., Guo, P. B., Zhu, B., Luong, J. H. T. (2015). Journal of Power Sources. 102. Rahimnejad, M., Bakeri, G., Najafpour, G., Ghasemi, M., & Oh, S. (2014). Biofuel Research Journal, 1, 7. 103. Hernández-Flores, G., Poggi-Varaldo, H. M., & Solorza-Feria, O. (2016). International Journal of Hydrogen Energy, 41, 23354. 104. Sugumar, M., Dharmalingam, S. (2020). Journal of Power Sources, 469, 228400. 105. Oh, S., & Logan, B. E. (2006). 162. 106. Kraytsberg, A., & Ein-Eli, Y. (2014). Energy and Fuels, 28, 7303. 107. Kreuer, K. D. (2001). Journal of Membrane Science, 185, 29. 108. Gebel, G. (2000). Polymer (Guildf), 41, 5829. 109. Angioni, S., Millia, L., Bruni, G., Ravelli, D., Mustarelli, P., & Quartarone, E. (2017). Journal of Power Sources, 348, 57. 110. Yang, J., Shen, P. K., Varcoe, J., & Wei, Z. (2009). Journal of Power Sources, 189, 1016. 111. Shahgaldi, S., Ghasemi, M., Ramli, W., Daud, W., Yaakob, Z., & Sedighi, M. (2014). Fuel Processing Technology, 124, 290. 112. Toikkanen, O., Nisula, M., Pohjalainen, E., Hietala, S., Havansi, H., Ruotsalainen, J., Halttunen, S., Karppinen, M., & Kallio, T. (2015). Journal of Membrane Science, 495, 101. 113. Mokhtarian, N., Ghasemi, M., Wan Daud, W. R., Ismail, M., Najafpour, G., & Alam, J. (2013). Journal of Fuel Cell Science and Technology, 10, 41006. 114. Kumar, V., Kumar, P., Nandy, A., & Kundu, P. P. (2016). RSC Advances, 6, 23571. 115. Bazrgar bajestani, M., & Mousavi, S. A. (2016). International Journal of Hydrogen Energy, 41, 476. 116. Staiti, P., Aricò, A. S., Baglio, V., Lufrano, F., Passalacqua, E., & Antonucci, V. (2001). Solid State Ionics, 145, 101. 117. Angioni, S., Millia, L., Bruni, G., Tealdi, C., Mustarelli, P., & Quartarone, E. (2016). Journal of Power Sources, 334, 120.

196

M. M. Ghangrekar and B. R. Tiwari

118. Kumar, V., Kumar, P., Nandy, A., & Kundu, P. P. (2016). RSC Advances, 6, 21526. 119. Zaidi, S. M., Mikhailenko, S., Robertson, G., Guiver, M., & Kaliaguine, S. (2000). Journal of Membrane Science, 173, 17. 120. Sivasankaran, A., Sangeetha, D., & Ahn, Y. H. (2016). Chemical Engineering Journal, 289, 442. 121. Ayyaru, S., & Dharmalingam, S. (2011). Bioresource Technology, 102, 11167. 122. Sivsankaran, A., & Dharmalingam, S. (2015). Fuel, 159, 689. 123. Venkatesan, N. P., & Dharmalingam, S. (2017). Renewable Energy, 102, 77. 124. Kamaraj, S. K., Romano, S. M., Moreno, V. C., Poggi-Varaldo, H. M., & Solorza-Feria, O. (2015). Electrochimica Acta, 176, 555. 125. Sharifi, M., Marschall, R., Wilkening, M., & Wark, M. (2010). Journal of Power Sources, 195, 7781. 126. Venkatesan, N. P., & Dharmalingam, S. (2015). RSC Advances, 5, 84004. 127. Chen, G., Wei, B., Luo, Y., Logan, B. E., & Hickner, M. A. (2012). ACS Applied Materials and Interfaces , 4, 6454. 128. Chen, G., Zhang, F., Logan, B. E., & Hickner, M. A. (2013). Electrochemistry Communications, 34, 150. 129. Hoskins, D. L., Zhang, X., Hickner, M. A., & Logan, B. E. (2014). Bioresource Technology, 172, 156. 130. Wu, C. H., Liu, S. H., Chu, H. L., Li, Y. C., & Lin, C. W. (2017). Journal of the Taiwan Institute of Chemical Engineers, 78, 150. 131. Liu, S. H., Wu, C. H., & Lin, C. W. (2017). Biochemical Engineering Journal, 128, 210. 132. Gohil, J. M., & Karamanev, D. G. (2013). Journal of Power Sources, 243, 603. 133. Tiwari, B. R., Noori, M. T., & Ghangrekar, M. M. (2016). Materials Chemistry and Physics, 182, 86. 134. Khilari, S., Pandit, S., Ghangrekar, M. M., Pradhan, D., & Das, D. (2013). 52, 11579. 135. Rudra, R., Kumar, V., & Kundu, P. P. (2015). RSC Advances, 5, 83436. 136. Quartarone, E., & Mustarelli, P. (2012). Energy and Environmental Science, 5, 6436. 137. Kumar, V., Mondal, S., Nandy, A., & Kundu, P. P. (2016). Biochemical Engineering Journal, 111, 34. 138. Singha, S. S., Jana, T. T., Modestra, J. A. A., Naresh Kumar, A., Mohan, S. V. V., Kumar, A. N. (2016). Journal of Power Sources, 317, 143. 139. Zhou, M., Wang, H., Hassett, J., & Gu, T. (2013). 140. Zhong, Z., Xing, W., Liu, X., Jin, W., & Xu, N. (2007). Journal of Membrane Science, 301, 67. 141. Raychaudhuri, A., & Behera, M. (2020). Electrochimica Acta, 363, 137261. 142. Gajda, I., You, J., Santoro, C., Greenman, J., & Ieropoulos, I. A. (2020). Electrochimica Acta, 353, 136388. 143. Nath, D., & Ghangrekar, M. M. (2020). Scientific Reports, 10, 17185. 144. Behera, M., Jana, P. S., & Ghangrekar, M. M. (2010). Bioresource Technology, 101, 1183. 145. Frattini, D., Accardo, G., & Kwon, Y. (2020). Journal of Membrane Science, 599, 117843. 146. Carroll, D. (1959). GSA Bulletin, 70, 749. 147. Yousefi, V., Mohebbi-Kalhori, D., & Samimi, A. (2017). International Journal of Hydrogen Energy, 42, 1672. 148. Ghadge, A. N., & Ghangrekar, M. M. (2015). Electrochimica Acta, 166, 320. 149. Karim, N. A., & Kamarudin, S. K. (2013). Applied Energy, 103, 212. 150. Lu, M., & Li, S. F. Y. (2012). Critical Reviews in Environment Science and Technology, 42, 2504. 151. Rabaey, K., Boon, N., Siciliano, S. D., Verhaege, M., & Verstraete, W. (2004). Applied and Environment Microbiology, 70, 5373. 152. Park, D. O. O. H. (2000). 66, 1292. 153. Chaudhuri, S. K., & Lovley, D. R. (2003) 21, 1229. 154. Rabaey, K., Lissens, G., Siciliano, S. D., & Verstraete, W. (2003) 1531. 155. Oh, S., & Min, B. (2004). 38, 4900.

Development of Low-Cost Microbial Fuel Cell …

197

156. You, S., Zhao, Q., Zhang, J., Jiang, J., & Zhao, S. (2006). Journal of Power Sources, 162, 1409. 157. Pandit, S., Sengupta, A., Kale, S., & Das, D. (2011). Bioresource Technology, 102, 2736. 158. Ucar, D., Zhang, Y., & Angelidaki, I. (2017). Frontiers in Microbiology, 8, 1. 159. Wang, G., Huang, L., & Zhang, Y. (2008). Biotechnology Letters, 30, 1959. 160. Li, Y., Lu, A., Ding, H., Jin, S., Yan, Y., Wang, C., Zen, C., & Wang, X. (2009). Electrochemistry Communications, 11, 1496. 161. Li, Z., Zhang, X., & Lei, L. (2008). Process Biochemistry, 43, 1352. 162. Kim, C., Lee, C. R., Song, Y. E., Heo, J., Choi, S. M., Lim, D.-H., Cho, J., Park, C., Jang, M., & Kim, J. R. (2017). Chemical Engineering Journal, 328, 703. 163. Xafenias, N., Zhang, Y., & Banks, C. J. (2015). International Journal of Environmental Science and Technology, 12, 2435. 164. Huang, L., Chai, X., Chen, G., & Logan, B. E. (2011). Environmental Science and Technology, 45, 5025. 165. Xafenias, N., Zhang, Y., & Banks, C. J. (2013). Environmental Science and Technology, 47, 4512. 166. Hsu, L., Masuda, S. A., Nealson, K. H., & Pirbazari, M. (2012). RSC Advance 2, 5844. 167. Ter Heijne, A., Liu, F., van der Weijden, R., Weijma, J., Buisman, C. J. N., & Hamelers, H. V. M. (2010). Environmental Science and Technology, 44, 4376. 168. Ter Heijne, A., Hamelers, H. V. M., De Wilde, V., Rozendal, R. A., & Buisman, C. J. N. (2006). Environmental Science and Technology, 40, 5200. 169. Tao, H. C., Liang, M., Li, W., Zhang, L. J., Ni, J. R., & Wu, W. M. (2011). Journal of Hazardous Materials, 189, 186. 170. Tao, H. C., Zhang, L. J., Gao, Z. Y., & Wu, W. M. (2011). Bioresource Technology, 102, 10334. 171. Cheng, S. A., Wang, B. S., & Wang, Y. H. (2013). Bioresource Technology, 147, 332. 172. Wu, D., Huang, L., Quan, X., & Li Puma, G. (2016). Journal of Power Sources 307, 705. 173. Zhang, B., Zhao, H., Shi, C., Zhou, S., & Ni, J. (2009). Journal of Chemical Technology and Biotechnology, 84, 1780. 174. Li, J., Zhang, B., Song, Q., & Borthwick, A. G. L. (2016). RSC Advance, 6, 32940. 175. Qiu, R., Zhang, B., Li, J., Lv, Q., Wang, S., & Gu, Q. (2017). Journal of Power Sources, 359, 379. 176. Tao, H. C., Gao, Z. Y., Ding, H., Xu, N., & Wu, W. M. (2012). Bioresource Technology, 111, 92. 177. Choi, C., & Cui, Y. (2012). Bioresource Technology, 107, 522. 178. Ho, N. A. D., Babel, S., & Sombatmankhong, K. (2017). Environmental Science and Pollution Research, 24, 21024. 179. Yun-Hai, W., Bai-Shi, W., Bin, P., Qing-Yun, C., & Wei, Y. (2013). Applied Energy, 112, 1337. 180. Lim, B. S., Lu, H., Choi, C., & Liu, Z. X. (2014). Desalination and Water Treatment, 54, 3675. 181. Choi, C., & Hu, N. (2013). Bioresource Technology, 133, 589. 182. Zhong, L., Zhang, S., Wei, Y., & Bao, R. (2017). Biochemical Engineering Journal, 124, 6. 183. Huang, L., Chen, J., & Quan, X. (2010). 937. 184. Tandukar, M., Huber, S. J., Onodera, T., & Pavlostathis, S. G. (2009). Environmental Science and Technology, 43, 8159. 185. Zhang, B., Feng, C., Ni, J., Zhang, J., & Huang, W. (2012). Journal of Power Sources, 204, 34. 186. He, C. S., Mu, Z. X., Yang, H. Y., Wang, Y. Z., Mu, Y., & Yu, H. Q. (2015). Chemosphere, 140, 12. 187. Ghangrekar, M. M., Das, S., & Tiwari, R. R. (2020) 229. 188. Noori, M. T., Ganta, A., & Tiwari, B. R. (2020). Journal of Hazardous, Toxic and Radioactive Waste, 24, 3. 189. Chakraborty, I., Ghosh, N., Ghosh, D., Dubey, B. K., Pradhan, D., & Ghangrekar, M. M. (2020). International Journal of Hydrogen Energy, 45, 55.

198

M. M. Ghangrekar and B. R. Tiwari

190. Vu, M. T., Noori, M. T., & Min, B. (2020). Chemical Engineering Journal, 393, 124613. 191. Das, I., Noori, M. T., Shaikh, M., Ghangrekar, M. M., Ananthakrishnan, R., & Appl, A. C. S. (2020). Energy Mater, 3, 4. 192. Kumar, A. G., Saha, S., Tiwari, B. R., Ghangrekar, M. M., Das, A., Mukherjee, R., & Banerjee, S. (2020). Polymer Engineering and Science, 60, 9. 193. Kumar, A. G., Saha, S., Komber, H., Tiwari, B. R., Ghangrekar, M. M., Voit, B., & Banerjee, S. (2019). European Polymer Journal, 118.

Recent Developments in Energy Recovery from Sewage Treatment Plant Sludge via Anaerobic Digestion Raja Sonal Anand and Pramod Kumar

Abstract In recent years, there has been a paradigm shift towards exploring renewable sources of energy to reduce the dependence on fast depleting fossil fuels. Anaerobic digestion (AD) is a process that has potential to manage ever-increasing municipal sewage treatment plant (STP) sludge to protect our environment and recover energy in the form of biogas. This chapter presents a comprehensive review of the basic principles, process control, reactor design, biogas purification technologies and the energy utilization systems with a special focus on recent developments in the field for improving the process performance. Among the four stages in the process, hydrolysis is recognized to limit the process rate due to the recalcitrant properties of the sludge. Various physical, chemical and biological pre-treatment technologies have recently been implemented to accelerate the digestion through enhancing the rate of hydrolysis. These process parameters and their interactions are crucial to AD because they play a vital role in biogas production and regulate the metabolic conditions for growth of microorganisms. The centre of interest in the reactor design is the optimal utilization of sludge by enhancing its attachment to biomass. Besides, various biogas refinement techniques and systems for their utilization have been discussed. In a nutshell, this chapter reveals the current research and development trends of technological advancement in the energy recovery from STP sludge via its AD. Keywords Municipal sewage treatment plant sludge · Anaerobic digestion · Biogas production · Energy recovery · Waste to energy conversion

R. S. Anand (B) · P. Kumar Department of Civil Engineering, Indian Institute of Technology, Roorkee 247667, India e-mail: [email protected] P. Kumar e-mail: [email protected] © Springer Nature Switzerland AG 2022 S. Yadav et al. (eds.), Environmental Management in India: Waste to Wealth, https://doi.org/10.1007/978-3-030-93897-0_10

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1 Introduction In developing countries like India, substantial and sustained economic growth concomitant with high energy demand and scarce non-renewable energy reserves has widened the demand–supply gap and increased dependence on imports of energy resources. There is an urge to upgrade sustainable energy resources to reduce the overdependence on fossil fuels as well as to mitigate the environmental impacts of fossil fuels usage. The hunger of global energy can be satisfied by Biogas, a renewable and sustainable source of energy due to the property of being generated from available waste material like sewage sludge [1, 2]. In the present scenario, sewage treatment plant (STP) sludge disposal has also become a problem for the society. A large amount of sewage sludge (primary sludge and waste activated sludge) generated during the treatment of municipal and industrial wastewater is increasing continuously due to accelerated urbanisation which is characterised by population and industrial expansion and enhancing existing treatment technologies for better quality effluents [3]. Presence of high quantity of putrescible organic matter, 95–99% water, harmful pathogens and high disposal cost accounting for up to 30–50% of the total operational cost of wastewater treatment plants (WWTPs) make sewage sludge a critical problem. It must undergo some treatments to kill pathogens, to reduce its volume, to convert the highly putrescible organic matter into a relatively stable or inert matter and to boost its stability before its final disposal [4]. This processing of sludge not only ensures its safe disposal but may also produce useful by-products. At first, the primary and secondary sludge produced originally at 1–2% total solids are thickened by gravity, flotation or belt filtration to reduce its volume to approximately one-third of its original volume. Once this is achieved, the sludge is stabilized by various techniques that include anaerobic digestion (AD) as the oldest, well established and economically attractive method. Many countries have adopted AD of sewage sludge as the main treatment method of sludge [5]. AD is a conventional biological process in which degradation of organic matter occurs by a variety of symbiotic microorganisms, mostly. archaea and bacteria [6], in the absence of molecular oxygen. However, lignin and other cellulosic organic matter in industrial sludges are resistant to decomposition and remain unaltered even during prolonged digestion. Based on the involvement of different types of microbes and the enzymes secreted by them, the whole process is completed in four phases, viz. hydrolysis, acidogenesis, acetogenesis, and methanogenesis. It offers various benefits like low energy consumption, reduction in sludge volume, and biogas production that is a renewable energy form [1]. Conventional anaerobic digesters treat sludge with a total solids (TS) content of 2–5% because at increased TS, sludge viscosity increases and thus pumping, mixing and heat transfer all become expensive and inefficient [7]. Due to high water content in sludge, constructing big digesters is not always feasible in small-scale WWTPs as well as highly urbanized areas due to limited space. On the other hand, AD of low organic content waste results in lesser biogas production and low organic

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removal rate and thus reduces the potential benefit of the process [8]. High solid AD (HSAD) has therefore been recognized to be advantageous over Conventional Anaerobic Digestion (CAD) for various reasons, such as low energy requirements for heating, small digester volume and less material handling requirements [9]. It has only recently attracted special attention. It deals with the sludge with TS content higher than 8% in comparison to CAD with TS 2–6% [10]. Until now, very few researchers have worked on the mono-digestion of high solid sludge. In AD, hydrolysis is known to be rate-limiting step that leads to a slow rate of organic matter degradation and consequently requires high retention times. Various pre-treatment techniques have been implemented to improve the hydrolysis rate, increase biogas production, and enhance the quality of digested sludge. Another major concern, especially in the mono digestion of high solid AD, is the accumulation of ammonia produced during the breakdown of protein in sewage sludge. Free ammonical nitrogen is most toxic to methanogens as it can enter their cell membranes and cause proton imbalance, increase maintenance energy requirements, and suppress enzyme specific reaction. It is also reported that severe inhibition occurs when total ammonical nitrogen (TAN) concentration exceeds 4000 mg/L at any operating pH and temperature. This chapter addresses recent developments in reactor design and process control of AD for sludge disposal with energy recovery.

1.1 Anaerobic Digestion Process Anaerobic Digestion is a complex and delicate process due to the susceptibility of the microorganisms to augment to environmental conditions in the reactor. A schematic representation of the process is shown in Fig. 1. The exact mechanism, microbiology and the biochemistry of the process are however not fully understood at present. The hydrolysis process converts complex organics like carbohydrates, proteins, and fats to simple molecules by the action of extracellular enzymes released by hydrolyzing microbes. The simple molecules are converted into volatile fatty acids (acetate, propionate, butyrate, valerate) and CO2 , H2 in the acidogenesis. Acetogenesis breaks down heavy organic acids into acetic acid as well as CO2 and H2 . In the final stage, two types of methanogenic archaea act to produce biogas: the first converts acetate into methane and CO2 and the second metabolises CO2 and H2 to produce biogas [4].

1.1.1

Hydrolysis

Biomass or sludge flocs formed during the treatment of wastewater via the activated sludge process are aggregates of prokaryotic and eukaryotic microorganisms attached together by extracellular polymeric substances. It consists of 60–70% organic matter. Microbes cannot uptake complex organic matter like sludge flocs directly because large size objects cannot permeate through their cell membranes. Hydrolysing microbes, typically phagotrophs, release extracellular enzymes and

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Organic Compound (carbohydrate, protein, lipid) Phase 1 Hydrolysis: Di-monosaccharide, amino acid, free fay acid Phase 2 Acidogenis(Fermentaon) Volale fay acid(VFA), acetate, H2, CO2

Acetogenesis Acetate

Syntrophic acec oxidizing bacteria (SAOB)

Phase 3 Hydrogenesis H2, CO2

Phase 4 Acetate ulizing or Acetoclasc methanogens Biogas (40-70% CH4, CO2)

Syntrophic acec oxidizing bacteria (SAOB)

Fig. 1 Anaerobic digestion process model [21]

peroxides for depolymerization of the complex organic matter to produce small molecules that they as well as can uptake and use as food and energy source [11]. Table 1 shows various extracellular enzymes involved in hydrolysis. Some hydrolyzing bacteria secrete a specific enzyme while others, a group of extracellular enzymes. The large and varied community of hydrolyzing bacteria like Clostridia, Micrococci, Butyrivibrio, Bacteroides, Selenomonas, Fusobacterium, Streptococcus, etc. are involved for the proper hydrolysis of all the organic matter present in the substrate. Majority of the bacteria are obligate anaerobes, and a few are facultative anaerobes also. Hydrolysis is a slow process and may take several hours or even days in case of sludge [12]. It is, therefore, considered the rate-limiting step in the AD [4, 11, 13, 14]. Pre-treatment technologies accelerate the process and enhance the biogas production as well [14–19].

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Table 1 Substrate, their respective hydrolytic enzymes and the end products [20] Substrate

Enzymes

Breakdown products

Proteins

Proteinase

Amino acids

Cellulose

Cellulase

Glucose and cellobiose

Hemicellulose

Hemicellulase

Glucose, mannose, arabinose and xylose

Starch

Amylase

Glucose

Fats

Lipase

Glycerol and fatty acids

Pectin

Pectinase

Galactose, polygalacticuronic acid and arabinose

1.1.2

Acidogenesis

It is usually the fastest step in AD and converts hydrolyzed products into organic acids, alcohols, H2, and CO2 by fermentative microorganisms (Lactobacillus, Streptococcus, Bacillus Salmonella, Escherichia coli, etc.). Typically, the following reactions take place. C6 H12 O6 ↔ 2CH3 CH2 OH + 2CO2

(1)

C6 H12 O6 + 2H2 ↔ 2CH3 CH2 COOH + 2H2 O

(2)

C6 H12 O6 → 3CH3 COOH

(3)

In these microbe mediated reactions, glucose is first converted into an intermediate product pyruvic acid via glycolytic Embden- Meyerhof-Parnas (EMP) pathway. Pyruvic acid is then converted into various organic acids (formic, acetic, propionic, butyric acids), alcohols, aldehydes, and ketones depending on the availability of various microbial species in the reactor and the environmental conditions [22]. Amino acids are similarly converted into short-chain organic acids through Stickland reaction or reductive deamination and specific fermentative pathways. A pH drop is observed after the conversion which is a favorable condition for microbes in this and subsequent phases. Only acetic and propionic acids are the preferred precursors for the remaining process [1].

1.1.3

Acetogenesis

Acetogenic bacteria convert the acids typically acetic and propionic acids and alcohols formed in acidogenesis to acetate that can be consumed by methane formers in the subsequent phase. These are slow growing and very sensitive obligate anaerobes [23]. Acetogenesis is possible only when the partial pressure of hydrogen in the system is below 10–4 atm. Acetogens are also able to oxidize hydrogen by using CO2 to form acetate [24].

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Methanogenesis

This is the last step and accomplished by archaea called methanogens in AD. Methanogenic archaea are also obligate anaerobes and very sensitive to oxic environment and pH [25]. Two types of methanogenic archaea carry out methane production: aceticlastic methanogens convert acetate into methane and CO2 through decarboxylation and hydrogenotrophic methanogens that use hydrogen as an electron donor and CO2 as electron accepter to produce methane. The former is responsible for about 70% methane production in AD. Taxonomical studies have revealed the presence of genera rods (Methanobacterium, Methanobacillus) and spheres (Methanococcus, Methanothrix, and Methanosarcina) at mesophilic conditions in this phase. Only Methanothrix and Methanosarcina are acetoclastic methanogens, others being hydrogenotrophic methanogens. The latter grow fast with a maximum estimated doubling time of 6 h while the former takes about 2–3 days [1]. In this complex series of bioconversions, a syntrophic association is formed between acidogens and methanogens to maintain the stability of the digester. Interspecies hydrogen transfer occurs between these two stages in which H2 produced in fermentation is utilized by methanogens serving as hydrogen sink. The rate of uptake of H2 should be optimum otherwise propionate and butyrate conversion will be slowed down leading to accumulation of volatile fatty acids and consequently pH drop and process upsets [26].

2 Environmental Requirements and Control The AD process must be controlled by maintaining a pool of environmental conditions (pH, temperature, nutrients, volatile suspended solids, etc.) required for the proliferation of various microorganisms in the reactor.

2.1 Temperature Anaerobic microorganisms are very sensitive to temperature that affects their metabolism, growth rates and population dynamics. It also affects the process intermediates formed and the gas transfer rates in the reactor. Overall, it largely affects the digester performance. It also affects the syntrophic relationship by changing the partial pressure of H2 [4]. The AD can be carried out in three temperature range, psychrophilic ( Ni > Cu ≈ Co ≈ Mo > Mn [29]. Various studies have proved that supplementation of these trace elements in limited concentrations has improved the system performance [30, 31]. The bioavailable or exchangeable fraction of total concentration of trace nutrient determines the nutritional requirement of microorganisms [32, 33]. Despite the positive effects of supplementation of limited quantities of these trace elements in AD, their application is still limited due to their high costs. Huiliñir et al. [34] found that the use of fly ash as a source of trace metals enhanced AD in terms of increased methane production along with a reduction in volatile solids.

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(Nm3/m3 reactor, day)

Fig. 3 Effect of SRT on various parameters [25]

2.4 Retention Time For a completely mixed digester, Solid Retention Time (SRT) isthe same as the Hydraulic Retention Time (HRT) [26]. The rate of biomass growth in the digester must be at least equal to the rate of removal of the bacterial population via sludge withdrawal to maintain a bacterial rich population in the reactor and to avoid process failure. Retention time depends on the organic loading rate (OLR), substrate constituents and operating temperature [25]. Usually, the retention time of 15–20 days for mesophilic and 10–15 days for thermophilic digestion is required. A decrease in the SRT reduces the extent of the reactions and vice versa. SRT less than 8 days is not recommended because it results in accumulation of VFAs, inadequate destruction of organic matter especially lipids resulting in low volatile solids removal and less production of biogas [6]. The effect of SRT on biogas production, methane production, VFAs concentration and VS reduction rate can be seen in Fig. 3 [25].

2.5 OLR and Sludge Feed Composition Higher OLRs may result in more biogas production to an extent, but the stability of the process may have to be compromised in the long run. Higher OLRs may temporarily inhibit the microbial activity due to the addition of a huge volume of new material in the digester. An extreme high OLR results in higher hydrolysis and acidification leading to accumulation of VFAs thus, causing a drop in pH thus

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inhibiting methanogenic activity [25]. OLR also affects bacterial communities. Low OLR is characterised by dominance of Firmicutes, whereas high OLR is characterised by abundance of Gammaproteobacteria, Actinobacteria, Bacteroidetes, and Deferribacteres including other bacterial communities [35]. The optimal OLR has been found to be in the typical range of 1.6–4.8 kg VS/m3 /d [6].

2.6 Seeding and Mixing It is important to maintain a rich population of methanogens since the start-up of the digester to avoid acidification. Therefore, digesters are seeded with anaerobic sludge during the start-up to create a contact between seed sludge and substrate to reduce the start-up time and to enable a good development of the process. In this regard, the digesters must be properly mixed to enhance the contact for uniform blending of substrate and seed [6]. Mixing also helps in even distribution of incoming solids in suspension, microorganisms, nutrients, temperature, removal of end products of metabolism and destruction of foam and surface scum. High mixing intensity may harm the microbial community and can inhibit gas production [36].

3 Process Inhibition AD processes are vulnerable to instability due to the accumulation of certain intermediates and by-products among which free ammonia nitrogen, volatile fatty acids, and sulfide/sulfate are the most significant inhibitors that can ultimately lead to process failure. Recently, an increase in the process failure has been observed in a wide variety of substrates either by a change in population dynamics of microbes or inhibition of the microbial growth present in the digester [13]. Therefore, it is important to have an insight into the inhibition mechanisms and current research related to them.

3.1 Ammonia Inhibition Although some amount of total ammonia nitrogen is necessary for the growth of anaerobic microorganism and for providing the buffering capacity to the reactor, excessively high concentrations inhibit the bacterial growth leading to process failure. Procházka et al. [37] found the best performance of anaerobic digesters when operated at 600–800 mg/L of ammonia concentration (pH 7.2–7.5) under mesophilic conditions. The concentration of ammonia nitrogen is less than 200 mg/L caused loss of biomass and aceticlastic methanogenic activity resulting in less biogas production. Ammonia inhibition is frequent in high solid sludge due to high OLR. Lay et al. [38] reported that 170–3720 mg/L, 4090–5550 mg/L and 6000 mg/L concentration

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Fig. 4 Biochemistry of ammonia/ammonium w.r.t pH and temperature [41]

of ammonia nitrogen respectively dropped 10%, 50% and 100% of methanogenic activity. While levels up to 5000 mg/L is tolerated by acclimated microbes [39, 40], the concentration of 1500–2500 mg/L can cause inhibition for unacclimated microbes. Free ammonia is far more toxic than total ammonia. Figure 4 shows relative amounts of ammonia and ammonium ions at different pH. Ammonia inhibition may be avoided by co-digesting with carbon-rich substrate or diluting the substrate with water. Alternatively, acclimated microbial community to high levels of ammonia can be introduced to the digester to prevent instability [42]. Methanosarcina sp. has been reported highly tolerant to high ammonia levels [43].

3.2 Volatile Fatty Acids Recently, many researchers have studied the inhibition due to VFAs in the AD process. High concentrations of VFAs (6.7–9.0 mol/m3 ) are toxic to microorganisms, especially to methanogens. Once methanogens are disturbed, the removal rate of hydrogen and VFAs decreases resulting in accumulation of VFAs and drop in pH leading to process failure. The undissociated forms of VFAs can permeate through cell membranes where they dissociate that reduces pH and disrupt homeostasis [4]. The VFA inhibition can be reduced by adjusting C/N ratio, the addition of trace nutrients to the digester and separating the methanogenesis phase by employing a two-stage digestion system.

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3.3 Sulphide/Sulphate Sulphate reducing bacteria (SRB) reduce sulphates to sulphide that are toxic to methanogens at high levels. Two groups of SRB are involved in the process depending upon whether they produce fatty acids or use acetate. Group one sulphate reducers (genus-Desulfovibrio) can metabolise a variety of organic compounds to convert them into acetate. Group two sulphate reducers (genus-Desulfobacter) oxidise fatty acids especially acetate to CO2 while reducing sulphate to sulphide. Inhibition occurs by two ways: first, competition for substrate (acetate) among SRB, acetogen, and methanogen, secondly, sulphide produced during the metabolism of SRB is toxic to microorganisms present in the digester. When high sulphate concentration sludge is fed to the digester, the microbial population dynamics may gradually shift to a rich population of SRBs. The inhibition due to sulphide accumulation can be handled by the addition of a controlled amount of iron in the digester to form iron sulphide precipitates [4, 26].

4 Process Configurations The AD process is carried out in airtight digesters. Sludge is fed intermittently or continuously and is detained for a specific period in the digester depending upon the operating environmental conditions and sludge characteristics. The stabilized sludge is withdrawn intermittently or continuously from the digester. Sludge digesters are of two types: conventional or low rate digester and high rate or continuous digester. Conventional or low rate digesters were used in the early stages and are seldom built now. A combination of basic processes involved in these two digesters has been used to develop two-stage digesters.

4.1 High Rate or Continuous Digester This type of sludge digester is an improved form of standard rate digester. First, the raw sludge is thickened (up to 6% TS) and then fed more or less continuously to create steady state condition and to prevent shock loading. In high rate digester, the sludge is heated by external heat exchangers due to their ease of maintenance and flexibility and uniformly mixed either mechanically or by recirculating a portion of produced biogas through a compressor. As a result, a uniform environment is created in every corner of digester that improves the stability and efficiency of the digester. High rate digesters are generally operated at mesophilic or thermophilic temperatures [4, 6, 26]. A schematic representation of this type of digester is shown in Fig. 5.

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Fig. 5 Single-stage high rate digester [6]

4.2 Two-Stage Digester In two-stage digestion, a high rate digester is connected with a second tank. Digestion takes place primarily in the first tank where sludge is heated and mixed to maintain uniformity in the tank. Gas is generally produced in this tank only. Nearly, 67% and 90% biogas are produced in 5 and 14 days respectively in this digester only. The second tank is used to store the digested sludge for gravity thickening and to decant relatively clearer supernatant. If the roof of the second tank is covered with a floating cover, it can be used to store biogas produced. However, the amount of biogas produced is very low. A schematic diagram of two-stage digestion is presented in Fig. 6. This type of digestion was accepted in the past. It is hardly built in newer treatment plants [4, 6, 26].

4.3 Digester Design Considerations Ideally, digester design should depend on the fundamental understanding of principles and microbiology of the process. Since these principles had not been accepted completely in the past, several empirical methods based on certain parameters have been established to determine the preliminary size of the anaerobic digester. The objective of this review is to summarise the various methods that are used for the design of anaerobic digester.

4.3.1

Population

Under this design criteria, the digestion tank volume is determined by granting a fixed number of cubic meters per capita considering all the other important parameters

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Fig. 6 Schematic two-stage anaerobic digester [4]

constant. Typical design values are listed on Table 2. If, Industrial waste loads are also treated in WWTPs then, the capacities should be increased on a population equivalent basis. This type of design criteria is applied at places where analyses and volume of sludge to be digested is not available [4]. Table 2 Design criteria for sizing mesophilic complete-mix digester [4] Parameter

Units

Value Standard rate

High rate

Volume criteria Primary sludge

m3 /capita

0.06–0.08

0.03–0.06

Primary sludge + trickling filter humus sludge

m3 /capita

0.06–0.14

0.07–0.09

Primary sludge + activated sludge

m3 /capita

0.06–0.08

0.07–0.11

Solids loading rate

KgVSS/m3 d

0.64–1.60

1.6–4.8

Solids retention time

d

30–60

10–20

Primary sludge + biological sludge feed

%

2–4

4–7

Digested sludge draw off

%

4–6

4–7

Sludge concentration

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4.3.2

213

Operating temperature, (°C)

SRTminimum (d)

SRTdes (d)

18

11

28

24

8

20

30

6

14

35

4

10

40

4

10

Volumetric Solid Loading

It is a very frequent method applied to calculate the size of the digester. The most preferred loading is the mass of the volatile solids added per day per unit volume of the reactor. The solid loading is typically based on the monthly peak of the 2-week peak solids production. The maximum limit of VS loading depends on the toxic materials accumulation rate or methanogen washout rate. Typical loading criteria are listed in Table 2. to determine the size of the digester [4, 26].

4.3.3

Solid Retention Time

The digester capacity can also be determined based on SRT since AD is affected by SRT. The peak hydraulic loading must be considered while determining the digester capacity based on SRT. Typical SRT values are reported in Table 3. Since these values were determined in ideal conditions, a safety margin (typically 2.5) must be considered to counteract the effect [4].

4.3.4

Volatile Solids Reduction

Since AD is a stabilization technique it can also be designed based on the degree of stabilization which is characterised by volatile solids reduction. The amount of volatile solids destroyed can be estimated by the following empirical equation. Vd = 13.7 ∗ ln(S RTdes ) + 18.9 where V d is percentage of volatile solids destroyed and SRT des the digestion time (d). Volatile solids destruction can also be estimated using Table 4.

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Table 4 Estimated volatile solids destruction in high rate complete mix mesophilic digesters [4]

4.3.5

Digestion time, (d)

Volatile solids destruction, (%)

30

65.5

20

60.0

15

56.0

Gas Production

Digester gas is composed of CH4 (65–70%), CO2 (25–30%), and some trace amounts of N2 , H2 , N2 , water vapour, H2 S and other gases. It has a heating value 21–25 Mj/m3 that is 30–40% lower than natural gas and a specific gravity of approximately 0.86 relative to air. There are kinetic equations available to estimate the volumetric methane gas. Appels et al. [4] can be referred for more details. Typical values of specific gas production vary from 0.75 to 1.12 m3 /kg 3 3 VersuS destroyed, or 0.5–0.75 m /kg VSloading , or 0.03–0.04 m /person day [4].

4.3.6

Tank Design

Cylindrical and egg-shaped tanks are commonly used in AD. The diameter of the cylindrical tank varies from 6 to 40 m. It has a conical bottom with a slope of about 15%, and sludge withdrawal takes place from the centre of the conical bottom. A minimum of 7.5 m water depth should be maintained for proper mixing and has the upper limit of 15 m [4]. Egg-shaped tanks are relatively high and designed to achieve better mixing and to get rid of cleaning.

4.3.7

Digester Mixing

Although natural mixing is achieved to some extent in the digester due to the rise of gas bubbles and creation of convection currents, auxiliary mixing is required for the optimum performance of the digester [4]. Gas injection, mechanical stirring, and mechanical pumping are used commonly for auxiliary mixing in the digester. All the types of auxiliary mixing are discussed in literature [26].

5 Pre-treatment Recently, many pre-treatment technologies have come into practice for improving the rate of hydrolysis in AD. These pre-treatment technologies burst the cell membranes resulting in disintegration of cells, decrease in the degree of polymerization and increase the bioavailability of organics. These technologies may be physical, chemical and biological types.

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5.1 Physical Pre-treatment Physical pre-treatments include mechanical (high-pressure homogenizer, mechanical jet, and mechanical ball mill), thermal, ultrasonic, microwave irradiation (MW) and electro-kinetic disintegration.

5.1.1

Mechanical Pre-treatment

In the mechanical pre-treatment, physical disintegration of cells and partial solubilisation of their contents are employed. However, mechanical pre-treatments are not frequently applied due to their low efficiency in comparison to other pre-treatment technologies [4]. High-pressure homogenization is a widely applied pre-treatment technology for full-scale operations. In this technology, sludge is compressed to 60 MPa then, depressurized through a valve and thrown at high speed on an impacting ring. The cell disruption takes place due to turbulence, cavitation and shear stress created during this operation. Harrison [44] described using colloid mill (with a stationary and rotating disc, and high-speed shaker ball mill) for disruption of microbial cells. Glass beads were introduced in the reactor fitted with moving impellers. Kinetic energy transfers from moving impeller to grinding glass beads created high shear stress that disrupted the cell wall. Thermal pre-treatment is the most effective and widely used technology. The sludge is usually subjected to an optimal temperature range from 150 to 200 °C for 30–60 min duration. In addition, 600–2500 kPa pressure is applied. Optimum temperature, pressure, and HRT depend upon the nature of sludge. When sludge is heated temperatures, the chemical bonds of the microbial cell walls start disrupting, and cell lysis takes place resulting in improved solubilization of cell organics. Usually, mesophilic range coupled with thermal hydrolysis produces more gas than that with thermophilic digestion. [4, 45].

5.1.2

Ultrasonic Pre-treatment

Ultrasonication is the most effective tool to disrupt microbial cells. Although 100% cell disruption can be achieved at high intensities, power consumption increases the overall processing cost. Ultrasonication is based on induced cavitation process. Gas bubbles are generated during the passage of ultrasonic waves that subsequently compress and expand reaching to a critical level where they implode creating extreme local conditions of temperature and pressure (up to 500 bar). The effectiveness of this process depends on the intensity and frequency of ultrasonic waves. Generally, ultrasonic devices are operated at frequencies between 20 and 40 kHz and power intensity ranging from 50 to 80 Watts to more than 20,000 Watts [4, 45]. A schematic diagram of ultrasonic equipment is shown in Fig. 7.

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Fig. 7 A schematic diagram of ultrasonic equipment [47]

Recently, Geng et al. (2016) reported an increase in VS removal of WAS from 21.5% to 33.7% on application of this pre-treatment at 41 kHz for 150 min. Also, ultrasonic pre-treatment at 20 kHz for the 60 s resulted in 24% biogas increment. The effect of ultrasonic pre-treatment was reported more significant in mesophilic digestion than thermophilic digestion in terms of COD removal efficiency and biogas production [45].

5.1.3

Electrokinetic Disintegration

Electro-kinetic disintegration is a recently developed technology to pre-treat the sludge on industrial scale. In this process, immediate breakage of sludge floc and microbial cell walls takes place through electric charges produced when sludge is subjected to high voltage electric field. Rittmann et al. [48] reported an 40% increase

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in biogas production by pretreating 63% of input waste sludge by electro kinetic disintegration.

5.1.4

Microwave Pre-treatment

Microwave (MW) is an effective alternative to in situ heating of sludge. The operating wavelength and frequency of microwave irradiation are 1 mm−1 m and 0.3–300 GHz respectively. MW irradiation destroys the microbial cells in two ways: (i) under oscillating electromagnetic fields, heat energy is produced through the rotation of dipoles that heats the intracellular fluids to boiling point which ruptures the microbial cell and (ii) due to altering dipole locations of polar molecules, heat energy is induced that possibly breaks the hydrogen bond to unfold and denature the complex bioorganics and consequently kill the microbes at low temperature. Some industrial and lab scale physical pre-treatment technologies have been summarised in Tables 5 and 6 respectively. Table 5 Pre-treatment technologies applied at industrial scale [14] Pre-treatment Thermal hydrolysis Commercial technologies

Ultrasonication High-pressure Electrokinetic Microwave homogenizer disintegration

Biothelys Sonix (2006): 10 plants

Crown

OpenCEL

PraxairR Lyso™

Turbotec (2011): 1 pilot

–

–

–

Biorefinex – (2013): 1 plant

–

–

–

CTH (2012): 1 plant

Sonolyzer

–

–

–

Exelys (2010): 1 plant

Iwe.Tec

Cellruptor

PowerMod

–

Lysotherm Hielscher (2012): 1 plant

–

–

–

Cambi Biosonator (1995): 20 plants

MicroSludge

Biocrack

Aspal SLUDGE™

Smart DMS

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Table 6 Microwave pre-treatment technologies tested at lab scale [19, 51, 52] Sludge type

Pre-treatment Environmental conditions

Anaerobic digestion Effects

Conditions

Performance

Thickened sludge 2.45 GHz, (43.6 g TS/kg) 800 W, 1 min, 96 kJ/kg TS

SCOD increment Semi-continuous, Increment in 117% 37 °C, HRT 20 d, biogas 67 d production by 20%

Activated sludge (40.8 g TS/kg)

800 W, 3.5 min, 336 kJ/kg TS,

SCOD increment Semi-continuous, Increment in 214% 37 °C, SRT 20 d, biogas 42 d production and dissolved solids removal by 50% and 66% respectively

Waste activated sludge

14000 kJ/ kg TS

Increase of 20–35% of biodegradability

Dewatered sludge Heating ramp *NR cake rate of 3–11 °C/min and final temp of pre-treatment of 80–160 °C Waste activated sludge

600 W, 85 °C, 2 min

Batch, mesophilic, 25 days

0.257–0.386 m3 biogas/kg VS

NR

Increment in methane yield and biogas yield by 22.6% and 24.7% respectively at 80 °C

Increase of COD NR solubilisation up to 8.5%

NR

*NR, not reported

5.2 Chemical Pre-treatment In chemical pre-treatment, strong chemical reagents (generally acid, alkali, and oxidants) are used to destroy the microbial cell membranes that make the intracellular organics amenable to biological degradation. The chemical pre-treatment is usually carried out at moderate or ambient temperature that reduces the necessity of conditional heating of sludges. Alkali pre-treatment has an additional advantage over other chemical pre-treatment, viz. it provides additional alkalinity to increase the buffering capacity of digester that helps in neutralisation of VFAs and improves methanogenic activity and system stability. Alkaline reagents used in the treatment processes ordered in terms of their effectiveness are NaOH > KOH > Mg(OH)2 and Ca(OH)2 . Acidic reagents used for pre-treatment are HCl, H2 SO4 , H3 PO4, and HNO3 . Acidic reagents perform better than alkali in removing hemicellulose pre-treatment while the latter is effective in lignin breakdown. Among all the oxidation techniques, ozonation has successfully used to bypass the hydrolysis stage and to disrupt the cell membrane for improved sludge COD solubilization. This process is energy intensive

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and requires that the optimum doses in the range 0.05 to 0.5 g O3 /g TS, depending upon sludge characteristics and pre-treatment conditions. Fenton oxidation is another oxidation process in which H2 O2 with catalyst iron (Fe2+ ) is used for disintegration of sludge EPS and disruption of cell membranes. Various researchers have tested chemical pre-treatment with sludge at laboratory scale as reported in Table 7 [19]. Combined pre-treatment has also been examined to enhance digestibility and gas production. A study [49] reported the highest hydrolysis rate of 211 mg/L min was obtained in combined alkaline and ultrasonic pre-treatment of sludge, more than that in individual cases. Ariunbaatar et al. [50] studied the combined pre-treatment of 1 h at 19–21 bar pressure and 160–180 °C resulted in a 75% increase in biogas production at steady state, as well as improved dewatering characteristics that resulted in a 25% reduction in disposal cost. However, an increase in ammonia concentration (64%) was observed due to increased hydrolysis of proteins that led to process instability.

5.3 Biological Pre-treatment Biological pre-treatment can be applied to sewage sludge by addition of either commercially available enzymes before the AD process or specific microbial strains secreting certain enzymes that hydrolyse the sewage sludge. However, the pretreatment via the addition of commercial enzymes is limited due to the high cost of enzymes. Therefore, the economically feasible way to biological pre-treatment is by addition of specific hydrolysing microbes or bioaugmentation [54]. This pretreatment has been tested by various researchers. Yang et al. [55] reported that rate of hydrolysis improved from 10% to 68.43% at 50 °C by addition of industrial enzymes protease and amylase in the ratio of 1:3 respectively. In another study [56], 53% extra methane production was observed by adding hemicellulolytic bacteria. Industrial applications of biological pre-treatment have also been reported. An exclusive plug flow enzymatic hydrolysis process has been developed by United Utilities in UK to pre-treat the sewage sludge [1]. The biological pre-treatment is not limited to only the use of enzymes and microorganisms. Temperature-phased anaerobic digestion (TPAD), and microbial electrolysis cell (MEC) are also reported as methods of biological pre-treatment. TPAD is characterised by thermophilic hydrolysis and acidogenesis followed by mesophilic acetogenesis and methanogenesis. Thermophilic temperature regime enhances the hydrolysis and acidogenesis of substrate whereas, mesophilic temperature regime enhances syntrophic acetogenesis and methanogenesis [19]. MEC is also an emerging technology for producing methane through electromethanogenesis. In MEC, oxidation of substrate takes place at the anode by electrochemical bacteria while generating electrons protons and CO2 . The electrons are transferred to the anode and the protons to the solution. With a small voltage input, electrons move tothe cathode where electrochemically active bacteria accept them or the system uses cathodic H2 to drive methane formation [19, 57]. Recently, some

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Table 7 Chemical pre-treatment technologies tested at lab scale [19, 52, 53] Chemical Activated sludge (5% TS)

HCl (8.75 mL/kg wet sludge), pH 2

Solubility of carbohydrates and proteins increased 4 and 6 times, respectively

Semi-continuous, 35 °C, HRT 12 d

Methane yield increases 14.3%, polymer dosing decreased by 40%

DDCOD : around 60%

Continuous, 35 °C, HRT 20 d

Biogas yield increases by 74%, COD and TS removal improved by 36.4% and 33% respectively

Sewage sludge

NaOH (0.1 mol/L) Increase of DDCOD from 22.3% to 26.9%

Batch (BMP), 21 d

Organic removal improved by 26.4%, Slight increase in biogas yield by 1.5%

Activated sludge

O3 (10 mg/g TSS), 20 cycles, 30 s/cycle

DDCOD : 18%, VSS reduction: 18%

Batch, F/I 0.8, 35 °C, 20 d

Increment in specific biogas production and VSS reduction by 800% and 60% respectively,

Activated sludge

O3 (0.09 g/g MLSS), pH 11

COD solubilization: 40%, TS reduction: 30%

Lab-scale AS-MBR, 120 d

Solid degradation: 37%

Activated sludge (13.9 ± 0.2 g TS/L)

H2 O2 (50 mg /g TS), Fe (7 mg /g TS in sludge), pH 2.0,

11.9 times SCOD BMP, 37 ± 1 °C, increase 23 d

Increment in methane production and methane potential by 10% and 13% respectively

Sewage sludge (16.2 ± 1.5 g VS/L)

pH 8–12 for 6 days

Increase of SCOD 338%

+ 29.6% biogas yield under mesophilic condition

Waste activated sludge

157 g NaOH/kg TS

Viscosity of sludge is reduced by pretreatment

Activated sewage 130 °C, pH 10 sludge

Lab scale batch experiment, 60 d, mesophilic

Increase of 34% in methane production

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Fig. 8 A schematic diagram of MEC operation [57]

researchers have positively integrated MCE with AD systems to enhance methane production [58]. A schematic diagram of two chambers MEC is shown in Fig. 8.

6 Biogas Refinement Biogas produced from AD consists of major gases that include methane (50–60%), carbon dioxide (40–50%), nitrogen (0.1–1%) and trace gases like hydrogen sulphide, hydrogen, ammonia, oxygen, and carbon monoxide. In addition, biogas is saturated with water, dust particles and possibly with other trace contaminants like siloxanes, and aromatic compounds. Therefore, there is a great need to enrich and enhance the quality of biogas to increase the heating value and to meet the requirements of appliances for its further use as an energy source in different sectors. To date, the techniques available for the biogas purification at industrial scale include organic physical scrubbing (OPS), pressure swing adsorption (PSA), chemical scrubbing process (CSP), high-pressure water scrubbing (HPWS), membrane separation and cryogenic separation. Since CO2 is present in high amount, all the refining technologies primarily remove carbon dioxide from biogas. However, a pre-requisite stage is sometimes required to separate the trace contaminants (water, hydrogen sulphide, siloxanes, etc.) depending on the concentration of trace contaminants [59]. PSA is an established and mature technology with a market share of 21% [60]. PSA is done by the adsorption of CO2 to the surface of an absorbent material due to physical or van der Waals forces. This adsorption is generally achieved at high pressure producing methane-rich gas (95–99%). Although an extensive process control, high

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start-up and operating cost are required for the process, several leading companies (Carbotech, Acrona-systems, Cirmac, Gasrec, Strabag, Xebec Inc., etc.) have developed and applied this process at industrial scale with a capacity of treating biogas 10–10,000 m3 /h. Electricity and temperature swing adsorptions (ESA and TSA) are also effective for cleaning biogas. The regeneration of adsorbents in PSA, ESA, and TSA is done by reducing the pressure, passing electricity through and elevating the temperature of saturated adsorbents. The removal of CO2 , H2 S, moisture, and other impurities can be achieved simultaneously or individually depending upon the selectivity of adsorbent material. Adsorbents used in these processes include Carbon Cryogel Microspheres (CCM) and Carbon Xerogel Microspheres (CXM), cationic zeolites and activated carbon. CCM and CXM are used in TSA due to their highly porous and stable structure. ESA uses activated carbon semiconductor adsorbent due to large surface area and micropore volume. HPWS is a well-known and commonly used technology to clean biogas via solubilising various gas components especially CO2 and H2 S in water at high pressure since the solubility of H2 S and CO2 are more than that of CH4 in water. In this process, raw biogas is injected through the bottom of a packed column and water from the top at an operating pressure of 10 bars. Highly saturated water with H2 S, CO2 and a little amount of CH4 leaves the bottom of the column. This water is regenerated in the desorption column by decreasing the pressure or air stripping. A schematic diagram of HPWS with recirculation is shown in Fig. 9a. Air stripping is not done when the H2 S levels are high since sulphur accumulates in the water causing corrosion and other operational problems. Hence, it becomes necessary to pre-remove H2 S when a high concentration of H2 S is present in raw biogas. The purified biomethane must be dried since it becomes saturated with water. The water regeneration process consumes high energy that increases the overall cost of the process [4, 56, 57, 62, 63]. OPS also work on the same principle as HPWS except that it replaces water with an organic solvent to increase the solubility of CO2 . These organic solvents include methanol, polyethylene glycol ethers (PEG) and N-methyl pyrrolidone (NMP). A schematic diagram of OPS is shown in Fig. 9b. While improved efficiency is feasible by using organic solvents, this process is expensive due to the high cost of organic solvent, and high energy requirement during regeneration of organic solvent [59]. CSP involves the use of amine-based solvents like mono-ethanol-amine (MEA), di-ethanol-amine (DEA) and methyl di-ethanol-amine (MDEA). Recently, piperazine (PZ) has been used along with MDEA to increase the capacity of MDEA. In the amine scrubber system, the raw biogas is injected into the absorber where CO2 absorption takes place at an operating pressure of 1–2 bars. Waste amine solution saturated with CO2 is produced in the process enters the stripper where it is regenerated under high temperature (120–150 °C) and low pressure. Although highly concentrated methane content gas (over 99%) can be achieved with low operational cost, treatment of waste, chemical, contaminants, and corrosion increase the complexity of the process. Inorganic solvents (sodium, potassium, ammonium and calcium hydroxides) are also used in CSP. Agitation facilitates the absorption of CO2 in these alkaline solvents [4, 56, 57].

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Fig. 9 Schematic diagrams of biogas refinement technologies a. High-pressure water scrubber with recirculation. b. Organic physical scrubbing. c. Membrane separation [64]

Membrane-based methane separation has evolved over the last four decades and now has a large market share among all the refining technologies available these days. The efficiency of gas permeation through the membrane depends on its solubility and diffusivity across the membrane material. The raw biogas is fed to the membrane typically at a pressure 5–30 bar. CO2 , H2 O, H2, and H2 S permeate across

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the membrane and CH4 accumulates on the retentate side. A flow diagram of biogas treatment using membranes is shown in Fig. 9c. This process is very simple to operate, cheap, safe, easy to maintain and consumes less energy. After extensive development and optimization, the membrane-based separation now has the potential to improve the biogas quality at a methane recovery rate up to 99.5%. Commercially available polymeric membranes are polyamide (PI), polysulfone (PSF) and cellulose acetate (CA). The organic membranes are cheaply available, having high mechanical strength and excellent selective permeation properties. One downside of the polymeric membrane is plasticization of membranes due to the high partial pressure of CO2 in the raw biogas. It leads to swelling of the polymeric membranes that consequently loses its selectivity and allows CH4 permeation also. Some inorganic membranes (zeolite, activated carbon, silica, carbon nanotubes, and metal–organic framework) have also been tested at laboratory scale, but their industrial application has been limited due to the complicated fabrication process. The latest research is oriented towards developing mixed matrix membranes and development of. multistage membrane separation processes to simplify the operation, enhance the biogas quality and reduce the energy consumption in the process [4, 56, 57]. CS is based on the principle of liquefaction of biogas constituents at different temperature and pressure. Various equipment such as compressors, heat exchangers, turbines and distillation columns are required that increase the capital investment and operational cost due to energy consumption. Typically, biogas is upgraded in four steps: (i) dust particles, water, H2 S, and other undesirable pollutants are removed from raw biogas. (ii) biogas is subjected to a very high pressure (1000 kPa) and chilled to −25 °C. (iii) biogas is further chilled to around −55 °C since at this temperature CO2 liquifies and removed. (iv) Finally, further cooling to temperature −85 °C converts the remaining CO2 into solid form and removes from matrix. The purified gas is then depressurised for further use. A flow diagram of cryogenic separation is shown in Fig. 10. Biomethane (over 97% CH4 content) can be obtained through this process. This technology is new and still under development [4, 56, 57], and there are no commercial upgraded biogas facilities currently in operation in India [66].

Fig. 10 Simplified process flow diagram of CS [59]

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7 Biogas Utilization Systems Many countries are facing challenges to meet their energy demands sustainably and establishing an optimized pathway to use renewable energy. Biogas is accepted as fuel and successfully adopted into various energy sectors in many European countries. Various utilization routes available till date include (i) Pumping in into natural gas grids. (ii) generation of heat and steam in boilers. (iii) electricity and power generation with combined heat and power production (CHP). (iv) as a vehicular fuel, and (v) H2 production from methane [4, 60]. In India, biogas is utilized in cooking stoves at individual, household and community level. Ministry of new and renewable energy (MNRE) has installed 5 million families sized biogas plants (1–10 m3 biogas/day) to cater for rural cooking needs, and has the target of installing 12 million by the end of 2022 [68]. In addition, 5.5 MW power was generated by installing 400 biogas off-grid power plants. Unfortunately, only 56 are operational biogas based power plants in the country, and most of them are located in Kerala, Maharashtra and Karnataka [69]. Ravindra [66]has suggested the scope of utilization of upgraded biogas in rural and urban areas of India in (i) cooking (both in domestic and commercial sectors to replace the LPG and kerosene). (ii) industrial (application in production and manufacturing process), and (iii) automotive sector (in personal and commercial automobiles to replace petrol and diesel).

8 Challenges and Opportunities There are two major challenges faced by the AD process, viz. operational instability due to inhibition caused by the accumulation of various intermediates and by-products, and quality of digestate produced. During the processing of digestate to reduce the moisture content, phase separating equipment are used that result in nutrient loss (Nitrogen 43%, 25% total phosphorus). Biochar addition in AD can mitigate these problems to some extent by adsorbing the excess inhibiting compounds either present in the substrate or produced during AD. It can also retain the nutrients and prevent their leaching during the processing of digestate [70]. Among the pre-treatment technologies, mechanical, chemical and thermal pretreatments have been intensively researched with many patented commercial technologies. However, only limited investigations have been done on biological pretreatment. Another challenge is to develop an optimization tool that focusses on the scientific scope of each pretreatment technology from environment, economic and energy perspective [19]. Other challenges in biogas upgradation technologies include a reduction in maintainance cost, environmental impacts, and energy consumption. Development of membrane materials focussing on the high compatibility with various biogas components instead of achieving very high selectivity to enhance the process stability and

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to reduce the degradation of membranes due to raw biogas components (H2 S and NH3 ) is also a big challenge [59]. At present, Only 2.07 billion m3 /year biogas is produced in India that is very low compared to the estimated production of 29–48 billion m3 /year [69]. Mittal et al. [69] have reviewed the challenges to biogas dissemination in rural as well as urban areas in India (Tables 8 and 9). Indian government started various schemes like off—grid biogas power generation program, the National Biogas and Manure Management Program (NBMMP) and waste to energy program to promote biogas development. Table 8 Challenges to biogas technologies in rural areas [69] S. No

Barrier categories

Barriers

Barrier element

1

Economical/Financial

High investment and transaction cost

High upfront installation cost High level of bureaucracy Tough to get financial support due to Procedural delays

2

Market

Outcompetence due to other fuels

Abundance/ Cheap availability of some fuel like wood in rural areas

3

Social and cultural

Social bias Gender participation

Biogas produced by waste material like faeces, dead animal carcass are not collectively accepted by society Minor participation of women as decision makers

4

Regulatory barrier

Top-down policy approach

Stringent policy guidelines

5

Technical and infrastructural

Poor feedstock supply Technical services are not enough

Substrate and water are not mixed in accurate proportion While grazing cattle excreta droppings are scattered Poor performance of plants during winter Lack of trained workers for building and maintainance of plants

6

Information

Poor awareness

Lack of recognition of substrates for biogas production except commonly used cattle dung Inadeqate distribution of information of the technology and the incentive/perks given by the various ministries

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Table 9 Challenges to biogas technologies in urban areas [69] S. No

Barrier categories Barriers

1

Financial /Economical

High investment cost High upfront installation cost Poor financial policy approach Tough to get financial support High transaction cost by financial institutions due to Procedural delays, huge risk intuition and high rate of interest, No legal standards

Barrier elements

2

Market

Outcompetence due to other fuels Competition from other technologies i.e. composting, RDF,

Tariff from renewables and fossil-based electricity is low

3

Technical and Infrastructural

Poor technology access to technology Inferior feedstock quality Inadequate storage and waste treatment facilities

Well developed optimised technologies don’t exist So, for establishing huge projects an big scale we rely on foreign technologiesPoor source segregation

4

Institutional

Capabilities of the municipal corporations are restricted Poor coordination between policy makers in the government A few private companies take part in

In terms of feed in terrify, state and national policies are not aligned

9 Conclusions AD is an old, complex and well-established process in which volatile organic material is decomposed into biogas and other stable organic material by different microbial clusters under strictly anaerobic conditions. However, industrial scale application of AD with entire control of all the parameters is not possible with the present knowledge on AD. Hydrolysis is generally considered as the rate limiting step. Various pretreatments methods have been investigated to enhance the rate of hydrolysis and improve the process efficiency. Among the reported techniques, mechanical, thermal and chemical pre-treatments have been studied deeply and applied commercially, whereas up to now the literature on biological pre-treatments are scarce. Despite being considered as a well established commercially available technique, the global consumption is very limited due to strict upgradation before its use. This review found that, more efforts are needed to fulfil the knowledge gap between the various upgradation techniques and their large scale operations. In India, several financial and nonfinancial hurdles exist limiting the expansion of biogas technology and barriers differ actively between biogas system in rural and urban areas.

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10 Recommendations Attention be given to the optimization of the various factors or combination of two or more factors affecting the rates of the different steps of AD and hence the efficiency to promote digestion process performance, more studies related to the strengthening of microbial metabolism and stimulating the degradation of organic matter should be done. Government should pay attention on framing new policies and regulations to promote biogas usages and active participation of independent bodies to increase the amount of upgraded biogas. Acknowledgements The authors would like to express their gratitude to Government of India, Ministry of Human Resource Development (MHRD) for providing the financial assistantship.

References 1. Merlin Christy, P., Gopinath, L. R., & Divya, D. (2014). A review on anaerobic decomposition and enhancement of biogas production through enzymes and microorganisms. Renewable and Sustainable Energy Reviews, 34, 167–173. 2. Central Statistics Office. (2016). Energy statistics 2016. Ministry of Statistics and Programme Implementation Government of India. 3. Dai, X., Duan, N., Dong, B., & Dai, L. (2013). High-solids anaerobic co-digestion of sewage sludge and food waste in comparison with mono digestions: Stability and performance. Waste Management, 33(2), 308–316. 4. Appels, L., Baeyens, J., Degrève, J., & Dewil, R. (2008). Principles and potential of the anaerobic digestion of waste-activated sludge. Progress in Energy and Combustion Science, 34(6), 755–781. 5. Li, X., Peng, Y., He, Y., Wang, S., Guo, S., & Li, L. (2017). Anaerobic stabilization of waste activated sludge at different temperatures and solid retention times: Evaluation by sludge reduction, soluble chemical oxygen demand release and dehydration capability. Bioresource Technology, 227, 398–403. 6. Gurjar, B. R., & Tyagi, V. K. (2017). Sludge management. CRC Press. 7. Jolis, D. (2008). High-solids anaerobic digestion of municipal sludge pretreated by thermal hydrolysis. Water Environment Research, 80, 654–662. 8. Liao, X., Li, H., Zhang, Y., Liu, C., & Chen, Q. (2016). Accelerated high-solids anaerobic digestion of sewage sludge using low-temperature thermal pretreatment. International Biodeterioration and Biodegradation, 106, 141–149. 9. Guendouz, J., Buffiere, P., Cacho, J., Carrere, M., & Delgenes, J. P. (2008). High-solids anaerobic digestion: Comparison of three pilot scales. Water Science and Technology, 58(9), 1757–1763. 10. Li, H., Zhang, Y., Liu, C., Chen, Q., & Si, D. (2016). Evolution of microbial community along with increasing solid concentration during high-solids anaerobic digestion of sewage sludge. Bioresource Technology, 216, 87–94. 11. Song, G. J., & Feng, X. Y. (2011). Review of enzymatic sludge hydrolysis. Journal of Bioremediation and Biodegradation, 2(5), 130. 12. Paul, E., & Liu, Y. (2012). Biological sludge minimization and biomaterials/bioenergy. Wiley. 13. Yuan, H., & Zhu, N. (2016). Progress in inhibition mechanisms and process control of intermediates and by-products in sewage sludge anaerobic digestion. Renewable and Sustainable Energy Reviews, 58, 429–438.

Recent Developments in Energy Recovery …

229

14. Cano, R., Pérez-Elvira, S. I., & Fdz-Polanco, F. (2015). Energy feasibility study of sludge pretreatments: A review. Applied Energy, 149, 176–185. 15. Zhong, W., Zhang, Z., Luo, Y., Sun, S., Qiao, W., & Xiao, M. (2011). Effect of biological pretreatments in enhancing corn straw biogas production”. Bioresource Technology, 102(24), 11177–11182. 16. Luo, K., Yang, Q., Li, X. M., Yang, G. J., Liu, Y., Wang, D. B., Zheng, W., & Zeng, G. M. (2012). Hydrolysis kinetics in anaerobic digestion of waste activated sludge enhanced by α-amylase. Biochemical Engineering Journal, 62, 17–21. 17. Barber, W. P. F. (2016). Thermal hydrolysis for sewage treatment: A critical review. Water Research, 104, 53–71. 18. Carrère, H., Dumas, C., Battimelli, A., Batstone, D. J., Delgenès, J. P., Steyer, J. P., & Ferrer, I. (2010). Pretreatment methods to improve sludge anaerobic degradability: A review. Journal of Hazardous Materials, 183(1–3), 1–15. 19. Zhen, G., Lu, X., Kato, H., Zhao, Y., & Li, Y. Y. (2017). Overview of pretreatment strategies for enhancing sewage sludge disintegration and subsequent anaerobic digestion: Current advances, full-scale application and future perspectives. Renewable and Sustainable Energy Reviews, 69, 559–577. 20. Adekunle, K. F., & Okolie, J. A. (2015). A review of biochemical process of anaerobic digestion. Advances in Bioscience and Biotechnology, 6(3), 205–212. 21. Nzila, A. (2017). Mini review: Update on bioaugmentation in anaerobic processes for biogas production. Anaerobe, 46, 3–12. 22. Demirel, B., & Yenigün, O. (2002). Two-phase anaerobic digestion processes: A review. Journal of Chemical Technology and Biotechnology, 77(7), 743–755. 23. Xing, J., Criddle, C., & Hickey, R. (1997). Effects of a long-term periodic substrate perturbation on an anaerobic community. Water Research, 31(9), 2195–2204. 24. McCarty, P. L., & Smith, D. P. (1986). Anaerobic wastewater treatment. Environmental Science and Technology, 20(12), 1200–1206. 25. Mao, C., Feng, Y., Wang, X., & Ren, G. (2015). Review on research achievements of biogas from anaerobic digestion. Renewable and Sustainable Energy Reviews, 45, 540–555. 26. Tchobanoglous, G., Burtan, F. L., & Stensel, H. D. (2003). Wastewater engineering: Treatment and reuse. Tata McGraw-Hill. 27. Qiang, H., Niu, Q., Chi, Y., & Li, Y. (2013). Trace metals requirements for continuous thermophilic methane fermentation of high-solid food waste. Chemical Engineering Journal, 222, 330–336. 28. Schattauer, A., Abdoun, E., Weiland, P., Plöchl, M., & Heiermann, M. (2011). Abundance of trace elements in demonstration biogas plants. Biosystems Engineering, 108(1), 57–65. 29. Choong, Y. Y., Norli, I., Abdullah, A. Z., & Yhaya, M. F. (2016). Impacts of trace element supplementation on the performance of anaerobic digestion process: A critical review. Bioresource Technology, 209, 369–379. 30. Feng, Y., Zhang, Y., Quan, X., & Chen, S. (2014). Enhanced anaerobic digestion of waste activated sludge digestion by the addition of zero valent iron. Water Research, 52, 242–250. 31. Linville, J. L., Shen, Y., Schoene, R. P., Nguyen, M., Urgun-Demirtas, M., & Snyder, S. W. (2016). Impact of trace element additives on anaerobic digestion of sewage sludge with in-situ carbon dioxide sequestration. Process Biochemistry, 51(9), 1283–1289. 32. Amir, S., Hafidi, M., Merlina, G., & Revel, J. C. (2005). Sequential extraction of heavy metals during composting of sewage sludge. Chemosphere, 59(6), 801–810. 33. Hsu, J. H., & Lo, S. L. (2001). Effect of composting on characterization and leaching of copper, manganese, and zinc from swine manure. Environmental Pollution, 114(1), 119–127. 34. Huiliñir, C., Pinto-Villegas, P., Castillo, A., Montalvo, S., & Guerrero, L. (2017). Biochemical methane potential from sewage sludge: Effect of an aerobic pretreatment and fly ash addition as source of trace elements. Waste Management, 64, 140–148. 35. Rincón, B., Borja, R., González, J. M., Portillo, M. C., & Sáiz-Jiménez, C. (2008). Influence of organic loading rate and hydraulic retention time on the performance, stability and microbial communities of one-stage anaerobic digestion of two-phase olive mill solid residue. Biochemical Engineering Journal, 40(2), 253–261.

230

R. S. Anand and P. Kumar

36. Lindmark, J., Thorin, E., Bel Fdhila, R., & Dahlquist, E. (2014). Effects of mixing on the result of anaerobic digestion: Review. Renewable and Sustainable Energy Reviews, 40, 1030–1047. 37. Procházka, J., Dolejš, P., MácA, J., & Dohányos, M. (2012). Stability and inhibition of anaerobic processes caused by insufficiency or excess of ammonia nitrogen. Applied Microbiology and Biotechnology, 93(1), 439–447. 38. Lay, J., Li, Y., & Noike, T. (1998). The influence of pH and ammonia concentration on the methane production in high-solids digestion processes. Water Environment Research, 70(5), 1075–1082. 39. Garcia, M. L., & Angenent, L. T. (2009). Interaction between temperature and ammonia in mesophilic digesters for animal waste treatment. Water Research, 43(9), 2373–2382. 40. Hansen, K. H., Angelidaki, I., & Ahring, B. K. (1998). Anaerobic digestion of swine manure: Inhibition by ammonia. Water Research, 32(1), 5–12. 41. Fricke, K., Santen, H., Wallmann, R., Hüttner, A., & Dichtl, N. (2007). Operating problems in anaerobic digestion plants resulting from nitrogen in MSW. Waste Management, 27(1), 30–43. 42. Kovács, E., Wirth, R., Maróti, G., Bagi, Z., Nagy, K., Minárovits, J., Rákhely, G., & Kovács, K. L. (2015). Augmented biogas production from protein-rich substrates and associated metagenomic changes. Bioresource Technology, 178, 254–261. 43. De Vrieze, J., Hennebel, T., Boon, N., & Verstraete, W. (2012). Methanosarcina: The rediscovered methanogen for heavy duty biomethanation. Bioresource Technology, 112, 1–9. 44. Harrison, S. T. L. (1991). Bacterial cell disruption: A key unit operation in the recovery of intracellular products. Biotechnology Advances, 9(2), 217–240. 45. Mudhoo, A. (2012). Biogas production: pretreatment methods in anaerobic digestion. In A. Mudhoo (Ed.), Scrivener Publishing. 46. Geng, Y., Zhang, B., Du, L., Tang, Z., Li, Q., Zhou, Z., & Yin, X. (2016). Improving methane production during the anaerobic digestion of waste activated sludge: Cao-ultrasonic pretreatment and using different seed sludges. Procedia Environmental Sciences, 31, 743–752. 47. Seng, B., Khanal, S. K., & Visvanathan, C. (2010). Anaerobic digestion of waste activated sludge pretreated by a combined ultrasound and chemical process. Environmental Technology, 31(3), 257–265. 48. Rittmann, B. E., Lee, H., Zhang, H., Alder, J., Banaszak, J. E., & Lopez, R. (2018). Full-scale application of focused-pulsed pre-treatment for improving biosolids digestion and conversion to methane. 1895–1901. 49. Elliott, A., & Mahmood, T. (2012). Comparison of mechanical pretreatment methods for the enhancement of anaerobic digestion of pulp and paper waste activated sludge. Water Environment Research, 84(6), 497–505. 50. Ariunbaatar, J., Panico, A., Esposito, G., Pirozzi, F., & Lens, P. N. L. (2014). Pretreatment methods to enhance anaerobic digestion of organic solid waste. Applied Energy, 123, 143–156. 51. Atelge, M. R., Atabani, A. E., Banu, J. R., Krisa, D., Kaya, M., Eskicioglu, C., Kumar, G., Lee, C., Yildiz, Y. S, ¸ Unalan, S., & Mohanasundaram, R. (2020). A critical review of pretreatment technologies to enhance anaerobic digestion and energy recovery. Fuel, 270, 1–31. 52. Pilli, S., Pandey, A. K., Katiyar, A., Pandey, K., & Tyagi, R. D. (2020). Pre-treatment technologies to enhance anaerobic digestion. In sustainable sewage sludge management and resource efficiency. IntechOpen. 53. Wang, T., Xu, B., Zhang, X., Yang, Q., Xu, B., & Yang, P. (2018). Enhanced biogas production and dewaterability from sewage sludge with alkaline pretreatment at mesophilic and thermophilic temperatures. Water, Air, and Soil pollution, 229(57), 1–10. 54. Yu, S., Zhang, G., Li, J., Zhao, Z., & Kang, X. (2013). Effect of endogenous hydrolytic enzymes pretreatment on the anaerobic digestion of sludge. Bioresource Technology, 146, 758–761. 55. Yang, Q., Luo, K., Li, X. M., Wang, D. B., Zheng, W., Zeng, G. M., & Liu, J. J. (2010). Enhanced efficiency of biological excess sludge hydrolysis under anaerobic digestion by additional enzymes. Bioresource Technology, 101(9), 2924–2930. 56. Weiß, S., Tauber, M., Somitsch, W., Meincke, R., Müller, H., Berg, G., & Guebitz, G. M. (2010). Enhancement of biogas production by addition of hemicellulolytic bacteria immobilised on activated zeolite. Water Research, 44(6), 1970–1980.

Recent Developments in Energy Recovery …

231

57. Kadier, A., Simayi, Y., Abdeshahian, P., Azman, N. F., Chandrasekhar, K., & Kalil, M. S. (2016). A comprehensive review of microbial electrolysis cells (MEC) reactor designs and configurations for sustainable hydrogen gas production. Alexandria Engineering Journal, 55, 427–443. 58. Sasaki, D., Sasaki, K., Watanabe, A., Morita, M., Matsumoto, N., Igarashi, Y., & Ohmura, N. (2013). Operation of a cylindrical bioelectrochemical reactor containing carbon fiber fabric for efficient methane fermentation from thickened sewage sludge. Bioresource Technology, 129, 366–373. 59. Ullah Khan, I., Hafiz Dzarfan Othman, M., Hashim, H., Matsuura, T., Ismail, A. F., RezaeiDashtArzhandi, M., & Wan Azelee, I. (2017). Biogas as a renewable energy fuel – A review of biogas upgrading, utilisation and storage. Energy Conversion and Management, 150, 277–294. 60. Kapoor, R., Ghosh, P., Kumar, M., & Vijay, V. K. (2019). Evaluation of biogas upgrading technologies and future perspectives : A review. Environmental Science and Pollution Research, 26, 11631–11661. 61. Sahota, S., Shah, G., Ghosh, P., Kapoor, R., Sengupta, S., Singh, P., Vijay, V., Vijay, V. K., & Thakur, I. S. (2018). Review of trends in biogas upgradation technologies and future perspectives. Bioresource Technology Reports, 1, 79–88. 62. Adnan, A. I., Ong, M. Y., Nomanbhay, S., Chew, K. W., & Show, P. L. (2019). Technologies for biogas upgrading to biomethane : A review. Bioengineering, 6(4), 1–23. 63. Angelidaki, I., Xie, L., Luo, G., Zhang, Y., Oechsner, H., Lemmer, A., Munoz, R., & Kougias, P. G. (2019). Biogas upgrading: Current and emerging technologies. biofuels: Alternative feedstocks and conversion processes for the production of liquid and gaseous biofuels. Elsevier Inc. 64. Singhal, S., Agarwal, S., Arora, S., Sharma, P., & Singhal, N. (2017). Upgrading techniques for transformation of biogas to bio-CNG: A review. International Journal of Energy Research. 65. Miltner, M., Makaruk, A., & Harasek, M. (2017). Review on available biogas upgrading technologies and innovations towards advanced solutions. Journal of Cleaner Production, 161, 1329–1337. 66. Ravindra, P. (2015). Advances in bioprocess technology. Springer. 67. Hakawati, R., Smyth, B. M., McCullough, G., De Rosa, F., & Rooney, D. (2017). What is the most energy efficient route for biogas utilization: Heat, electricity or transport? Applied Energy, 206, 1076–1087. 68. Yousuf, A., Khan, M. R., Pirozzi, D., & Ab Wahid, Z. (2016). Financial sustainability of biogas technology: Barriers, opportunities, and solutions. Energy Sources, Part B: Economics, Planning and Policy, 11(9), 841–848. 69. Mittal, S., Ahlgren, E. O., & Shukla, P. R. (2018). Barriers to biogas dissemination in India: A review. Energy Policy, 112, 361–370. 70. Fagbohungbe, M. O., Herbert, B. M. J., Hurst, L., Li, H., Usmani, S. Q., & Semple, K. T. (2016). Impact of biochar on the anaerobic digestion of citrus peel waste. Bioresource Technology, 216, 142–149.

Waste and Sustainability

Management of Waste Plastic: Conversion and Its Degradation as an Environment Concern in Asian Country Pratibha, Sudesh Kumar, Supriya Singh, and Vanshika Singh

Abstract Plastic plays a dynamic role in enhancing the ordinary lives of a human being. The petition of plastics has been amplified because of the fast evolution of the world population. The worldwide creation of plastic has stretched approximately 322 million tons in 2017 and has amplified by 4% over 2018. Plastics are generally non-biodegradable and persist in the location for hundreds of years. High durability of plastic creates a great risk to the environment system i.e. landfill, emission of toxic gases like CO, CO2 , SO2 , NOx , global warming, acidic rain, depletion of the ozone layer, leaching of chemicals and pollution. Dangers allied through healthcare waste and its management has expanded devotion across the world in numerous procedures, local and international opportunities, and meetings. Though, the requirement for proper healthcare waste management has been gaining acknowledgment slowly because of substantial disease burdens allied through poor practices, with exposure to infectious agents and toxic substances. There is only a limited rule existing at the global level about decomposable plastics in soil. Conditions, constraints, and testing procedures aimed at classification, cataloguing, and authentication of cultivated plastic leftover torrents through probable biodegradation in soil rendering to present global values are analysed whereas appropriate disagreements are acknowledged. In this chapter, discussion about the management of healthcare waste, biodegradation of plastic in soil, household plastic, marine plastic at national and international level. Keywords Plastic waste · Population · Environment system · Biodegradation · Household

1 Introduction Plastics are a type of artificial organic polymers collected of extended, chain alike particles through a high average molecular weight. Numerous communal types of plastics are collected of hydrocarbons which are characteristically but not constantly consequent as of fossil oil feedstocks. Throughout translation as of resin towards Pratibha · S. Kumar (B) · S. Singh · V. Singh Department of Chemistry, Banasthali Vidyapith 304022, Rajasthan, India © Springer Nature Switzerland AG 2022 S. Yadav et al. (eds.), Environmental Management in India: Waste to Wealth, https://doi.org/10.1007/978-3-030-93897-0_11

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invention, an extensive diversity of essences together with putties, plasticizers, fire retardants, UV and thermal stabilizers and anti-microbial and colouring agents— might be supplementary towards resin to improve plastic’s presentation and presence. The consequence is a type of constituents which have exceedingly adaptable and necessary belongings. Original artificial polymers were established in the intermediate of the nineteenth era; quick progress of several innovative plastics formerly arisen in primary twentieth period and viable invention enhanced throughout World War II. Universal plastics creation enlarged exponentially later in 1950 using 311 million metric tons formed in 2014. Nowadays, seven service thermo-plastics interpretation aimed at ∼85% of the overall plastics petition designed for effectively entirely marketplace parts. Chief marketplace petition is designed for wrapping constituents that are premeditatedly meant for short period usage earlier discarding. The occurrence of plastics in the environment, whether as macro-plastic wreckage or as micro-plastics has extensively been recognised as a universal problem. It embodies one of the utmost stimulating anthropogenic phenomenon which disturbs our globe and is amongst the main intimidations to bio-diversity because of potential predicament and incorporation. More than two eras of continuous commercial progress have intensified delinquent of compact leftover in maximum Asian nations. As per approximation providing via Ministry of Environment, Government of Japan (2006), Asia created more than 3 billion tons of compact leftover in 2000 that might increase up to near 9 billion tons through 2050. Through great thrifts like China and India remaining towards spectator unrelieved progress and expansion, the condition might go downhill even further. Expanding dimensions of leftover positions a discrete hazard to forthcoming progress and wellbeing of Asian countries [1–3]. Deprivation is an elementary distinguishing of polymers and plastics. It is constructed on the circumstance which utmost of these constituents are organic composites which can undertake physical oxidation as well as instinctively and chemically encouraging deprivation. Through initial progress of polymers and plastics, deprivation was commonly a development which was to be reduced and ultimately circumvented in the direction towards agreement aimed at sturdiness and extensive amenity lifetime duration of plastics [4]. Recyclable plastics are existing nowadays in several divisions of budget; one of these divisions is cultivation. Universal extents of recyclable plastics in usage by European Level in 2007 was approximately 30,000 t representative solitary 0.06% of universal plastics usage of 47.5 Mt [5]. In France, for illustration, consistent data are 6.7 Mt of plastic, and 10,000 t are recyclable plastics representative 0.15% of the usage of plastics [6]. Recyclable polymers are progressively been used nowadays by way of alternatives of plastics aimed at numerous submissions of predictable cultivated plastics [7, 8]. Later 1960, Asia major and utmost overcrowded of islands has grownup wealthier than any supplementary district of the biosphere. Obviously, entirely advanced happenings consent behindhand approximately measures of leftover that have to be accomplished appropriately. Healthcare service station is no diverse in producing wildernesses. Their consideration in the direction of innocuous dumping of healthcare wildernesses is generally diluted.

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2 Healthcare Waste In current centuries, apprehension over the solid waste from health-care conveniences amplified all over the biosphere. This is due to waste arising primarily from hospitals and clinics, is potentially hazardous subsequently it can spread viruses due to the transmittable nature of the wastes and origin wound through the maladministration of clinical solid waste (CSW). Deprived deportment and unsuitable discarding approaches exercised throughout management and discarding of CSW is growing important fitness threats and environmental contamination because of the transmittable nature of the leftover. Utmost trustworthy explanation from WHO typifies healthcare waste (HCW) by way of those wildernesses created from infirmaries, health centres, healthcare institutions, and exploration conveniences in analysis, treatment, inoculation, and linked exploration. World Health Organization (WHO) projected that in 2000, about 23 million individuals were diseased through Hepatitis B, Hepatitis C, and HIV globally because of vaccinations by dirty needles in healthcare conveniences. Comparable belongings are predisposed to arise as soon as healthcare waste (HCW) is discarded in an uninhibited style and converts available to the community. Considerate very well that fitness and conservation problems are mainly associated with one another. It is important to take a united method in selection evolving nations report problems associated with healthcare leftover dumping broadly. Healthcare waste management (HCWM) consequences in adversative possessions on atmosphere and communal fitness. Utmost regularly distinguished problems in suitable HCWM are frequently innocuous dumping of wildernesses, work-related fitness, and protection aimed at healthcare employees and prohibited searching. Innocuous clearance of HCW involves four vital periods like exclusion, assortment and stowing, treatment, transference, and harmless dumping [9] wherever countrywide regulation must be tracked. Amongst healthcare wildernesses, sharps are of chief anxiety towards entirely healthcare operate similar, registrars, nurtures, midwives healthcare employees, and recyclers. Pointer stick wounds throughout dumping and repossession of used sharps are conceivable and have to be prohibited. In utmost of evolving nations, sale of used sharps and plastics is gainful. Later, there is a probable aimed at illicit reprocess of used sharps that origin a hazard to whole communal [10].

2.1 Management of Healthcare Waste Healthcare waste management is a composite issue specifically when observed on a district level through 12 nations divergent in edifying and commercial position. Nonetheless, assessment of healthcare waste management amongst these nations has to be completed on a communal stage enchanting approximately undeviating origin aimed at structures. Around 80% of all HCW can be inclined via consistent community leftover dumping procedures or guided aimed at reprocessing as in

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Governments and Policymakers

Hospital Top Management Provide budgetary support and motivation Department Heads Monitor and lead by example

Law enforcement Authories

Waste management Service providers

Formulate integrated, responsive, realistic and sound healthcare waste management policies and legislations

Ensure compliance with prevailing regulations, monitor and initiate action on violators

Insist on segregated waste adhering to prevailing regulations

Doctors, nurses, care takers of paents Ensure compliance with the system

Academia

Build capacity for beer healthcare waste management

Fig. 1 Spreading of responsibilities [11]

circumstance of additional internal leftover. It is other 20% which are theoretically transferable and fictional to generate stern fitness coercions towards employees and peoples if not predisposed subsequent prearranged procedures. Lacking foundation exclusion and recovering happenings in residence, infirmaries are enforced to dump basic leftover sideways through transferable leftover thus consequential in undesirable dumping expenses. Through taking a strong strategy, infirmaries can diminish the quantity of leftover they have to accomplish by way of transferrable until now manufacture supplementary proceeds [11] (Fig. 1).

3 Plastic Waste in Soil Recyclable plastics are nowadays in several divisions of areas. One of these divisions is cultivation. In France, for illustration, consistent data are 6.7 Mt of plastic, and 10,000 t are recyclable plastics representative 0.15% of the usage of plastics [12]. Recyclable polymers are progressively been used nowadays as alternatives of plastics aimed at numerous submissions of conservative cultivated plastics [7, 8] exclusively aimed at evolving cultivated films [13] nonetheless also vegetable containers, staples designed at rising vegetations, webs aimed at cultivation and forestry, nourishment belongings etc. [12]. Usage of recyclable plastics aimed at cultivated submissions is not so far announced generally in Europe excluding France wherever decomposable insulating film characterizes 3.6% of insulating films in usage. Key motive aimed at announcing decomposable plastics in farming submissions even at a deliberate

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step is that upward usage of plastics in farming that has empowered agriculturalists to growth their harvest creation is also connected through a main disadvantage. Due to inclusive usage of cultivated plastics, problem through dumping of farming, plastic wildernesses converts more and more unembellished and relatively difficult and affluent to explain [14–16]. For biodegradable plastic materials to be accepted in composting plants, both biodegradability and disintegration are significant. Disintegration is the physical falling apart of the bio-degradable plastic material. Biodegradable materials used in agricultural applications like clips, strings, etc., they are much thicker than thin films [17]. In Europe, withdrawal of dumpsites and remediation of contaminated property are nowadays predictable by way of central procedures aimed at the safety of airborne, property, and water possessions. Fortune of contaminants, transference machinery in muds and poison features are parameters of substantial position aimed at the strategy of remediation arrangements. Consequently, such constraints must be acknowledged previously, significant manufacturing procedures aimed at any full-sized remediation. Landfill mining (LFM) progresses diggings, transference and handing out of concealed substantial reserved as of a vigorous or bolted landfill. Resolutions of LFM have been [18]: (1) (2) (3) (4) (5) (6) (7) (8)

Maintenance of landfill space Decrease in landfill extent Exclusion of a possible foundation of infect Moderation of a prevailing infection cause Energy regaining Reprocessing of improved constituents Decrease in supervision arrangement expenses Location improvement.

3.1 Management of Plastic Waste in Soil Knowledge was announced in Israel in 1953 employing a process of cultivating mud excellence in groves [19]. In USA, LFM has been accepted primarily through the objective of improving oil aimed at energy making nonetheless few studies have also engrossed on reutilizing of exhumed substantial [20]. Original recognized LFM scheme was supported in Collier District, Florida, USA amongst 1986 and 1992 to afford additional oil aimed at a thermal power place. Throughout time from 1987 to 1993, diggings were supported at six landfills in USA through the goal of finding layer substantial [21]. In several places, demonstration ventures were originated [22]. In 1997, around 40 landfill-mining ventures were at diverse points of execution in USA and Canada [21]. For decomposable plastic constituents to be acknowledged in composting vegetations, together biodegradability and fragmentation are significant. A compostable substantial is unstated to be a substantial aimed at which [6]:

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• Polymer chains interruption below exploits of micro-organisms. • Overall mineralisation is attained. • Mineralisation proportion is high and is companionable through composting progression. ASTM standard testing procedures appropriate to trying compos-ability of plastics. Main necessities established through ASTM standards aimed at cataloguing of constituents and products together with wrapping completed as of plastics by way of “compostable in community and manufacturing composting facilities”, might be defined briefly as follows [6]: (1) (2)

(3)

(4)

60% of solitary polymer constituents must mineralize within 6 months. Polymer assortments, co-polymers, and plastics through low molecular weight extracts or plasticizers must display 90% biodegradability in similar period edge. Constituents in invention arrangement must illustration powerful bacteriological commotion, and are transformed as of carbon to carbon dioxide, biomass, and water. They must dis-integrate into trashes through less than 10% of substantial being trapped on 2 mm filters. Lastly, afterward land submission, residual constituents must not be noxious or perimeter vegetable progress. Structured metals gratified in polymer would be less than 50% of EPA prearranged beginning. Ecotoxicity examinations are supported in agreement through ASTM D6400 towards verifying that it is compostable.

4 Municipal Solid Waste Municipal Solid Waste (MSW) is a heterogeneous leftover torrent that is injurious for humanoid fitness and conservation atmosphere if it is not correctly accomplished. Inappropriate MSW dumping and supervision origins all kinds of contamination: air, soil, and water. Undiscerning discarding of wastes pollutes surface and ground water supplies. In city extents, MSW clogs sanitations, generating stationary water aimed at bug breeding and torrents throughout rainy periods. Unrestrained burning of MSW and inappropriate ignition donates expressively to city air pollution. Biosphere residents were 3 billion in 1960 that has enlarged to 7 billion in 2011, and it is projected to influence 8.1 billion through 2025 [23]. Entire MSW generation has enlarged from 31,320 thousand tons in 1980 to approximately 178,602 thousand tons in 2017, and MSW generation per capita has also enlarged from 448.3 g to 653.2 g. Dispersal of MSW generation is frequently focused in the littoral south-eastern area as well as great fact foundations of more than 200 thousand tons per year are generally circulated in Jiangsu, Zhejiang, Shandong, Hebei and Guangdong shires. Related through manufacturing hard leftover, medicinal leftover, and erection leftover. MSW has features of non-point foundation trash [24, 25]. As major evolving nations, China

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merits superior consideration. Rendering to earlier studies [26], China formed around 30% of biosphere’s MSW in 2012, and this MSW is a growing concern. Facing this burden, China has dedicated significant struggle towards supervision its MSW. Worldwide town residents are growing at a fast rate than that of overall residents [27]. At extant, more than partial of biosphere residents conscious in town extents therefore universal appreciation of MSW generation is chiefly because of populace progress, urbanisation, and commercial expansion [28]. Currently, per capita MSW generation degree in established nations is more than that of evolving nations due to generation degree based on commercial and societal affluence of a nation. It was projected that in approaching eras evolving nations of Asia and additional portions of the biosphere would contest MSW generation degree of established nations [29]. Gradually, publics of evolving nations are adjusting routine of established lands because of globalisation resultant in the generation of huge extents of wildernesses. Therefore, appreciation in MSW generation degree is chiefly because of shifting nutrition traditions, ingesting form, and existing ethics of city people [30].

4.1 Management of Municipal Solid Waste A momentous revolution arose through China’s 13th Five-Year Strategy that was unconstrained on March 17th, 2016 and its elevation of numerous assignments of MSWM together with leftover decrease, reutilizing and composting, handling knowledge, apparatus and organization and monitoring arrangements. Enhancement of MSWM approaches is a significant goal aimed at Chinese management in centuries to originated, and the entire characteristics of China’s MSWM will have to undertake excessive reorganization to accomplish this goal [31]. Presently fossil oils are utmost consistent foundations of energy meeting nearly 84% of worldwide energy petition [32]. It is period to realise probable of waste to energy (WTE) as a choice aimed at the supportable hard leftover organization and as one of utmost momentous imminent renewable energy foundations that is frugally practicable and naturally supportable [33, 34]. Ali et al. [35] determined that WTE is not individual supportable leftover managing resolution nonetheless also a cautiously achievable particularly aimed at established nations. Nations that trained high degree of energy repossession from wildernesses had considerable rates of reutilizing while for evolving nations wherever land-filling is utmost predominant leftover managing selection, reutilizing rates were truncated [36]. Arafat et al. [37] described normally recoverable energy fillings aimed at diverse mechanisms of MSW utilizing diverse WTE skills. Ignition remainders an attractive choice among entire leftover torrents as it can be used aimed at energy recovery as of altogether informed leftover torrents. Though, additional kinds of wildernesses like inactive, metals, glass, etc. were not measured in that study.

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5 Household Waste Plastic and Its Management In the previous two eras, China has perceived a debauched development in its economy. Though continually growing residents and enhanced expansion have instigated a growth in the generation of household leftover [38]. Recent announcements regarding restrictions at national level on a wider array of single-use plastics, include the proposed directive from the European Union to implement consumption reduction and market reduction measures on food containers, cups for beverages, cotton bud sticks, cutlery, plates, stirrers, straws and sticks for balloons, and to push for a 90% collection rate of single-use plastic bottles [39]. Hard leftover trash and its organization are flattering main problems throughout the nation. On the other hand, organization of dense leftover as of households is vitally aimed at several explanations. One of these is that landfill interplanetary is flattering a threatened reserve in several nations. Additional reflective is feasibly apprehension aimed at conservation harm as of harmful mechanisms in leftover composed through metropolis will not repeatedly improve apprehension around the spread of dangerous leftover into the atmosphere [40]. Jenkins [41] has established a prototypical wherever households exploit efficacy that based completely on the extent of belongings used up and undesirably on expanse of reutilizing. Involved in household inexpensive limitation is a discarding responsibility aimed at SWS. Additional variables which disturb claim aimed at SWS are household profits, values of possessions expended, expense aimed at recycled things, magnitude and stage of development circulation of household, climate circumstances and gradation of development. Petition aimed at leftover assortment facilities is presumed to be an occupation of incremental payment accompanying through diminishing a supplementary container aimed at leftover dumping and prospect rate of cataloguing leftover into recyclables and non-recyclables, now equivalent to female remuneration proportion. Sum of individuals per household, edification level, competition and lease or proprietorship of their community was similarly supposed to encouragement petition aimed at SWS. Consequences designate an encouraging but minor relation amongst an improved expense transformation and request aimed at the extent of leftover composed. Morris and Holthausen [42] projected a household making prototypical of dense leftover organization and employed an abridged type with facts on household expenses and leftover streams in Perkasie in two ages. One of the influences that applies a huge physical consequence on request aimed at a dense leftover organization is gradation to which individuals essentially fix nourishment. A compostable segment of household wildernesses can lie in assortment as of around 30–50%. The most important determinants of every individual household’s waste were composting of kitchen waste, living area, age and attitudes concerning the complexity of re-cycling diverse materials [43] (Fig. 2).

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Fig. 2 Several usages of recycled plastics [43]

6 Marine Waste Plastic Plastic and micro-plastic pollution in aquatic environments has been gaining cumulative consideration. The problem of plastic pollution in the worldly environment has continued generally unfamiliar. Plastic and micro-plastic contamination may be additional intensely perceived in the oceans. Though, more than 80% of the plastics originate in aquatic environments has been formed, expended and predisposed of on terrestrial. Consequently, plastic contamination on terrestrial is a problem together of pollution and impairment to worldly environments and of transference to marine structures [44]. Plastic trash in marine was originally described through researchers in 1970s so far in current centuries it has strained incredible consideration as of media, community and a growing quantity of researchers crossing various arenas together with polymer science, conservational manufacturing, environmental science, toxicology, aquatic biology, and oceanography. Tremendously perceptible wildlife of considerable of this uncleanness is informal to transport in scandalous imaginings of loads of garbage on seaboards, aquatic creatures intertwined in trawling nettings or seabird tummies occupied through flask stoppers, cigarette lighters and colourful ruins of plastic. Even deprived of these imaginings, anybody who has to go to a seaside has unquestionably met waste cigarette butts, fragmented seaside figurines leftover or shards of trawling equipment or signals that wash away aground. Whether as a consequence of instinctive retort conjured through these involvements or growing responsiveness which plastics are abundant and determined in ordinary organizations. This conservation apprehension is being lectured at maximum worldwide stages [45, 46]. One main foundation of plastics to the sea, which has been predictable worldwide is inappropriately accomplished plastic leftover produced on land-living [45].

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This examination used information accumulated through World Bank [26] on per capita leftover generation proportion, leftover conformation and leftover dumping in 192 seaside nations to guesstimate overall volume of plastic leftover generated and quantity which is uncontrolled due to inappropriate managing. The amount of plastics entering aquatic environments depends on the following. (1) (2) (3) (4) (5)

Climatic conditions of the area. Topography and vegetation. Plastic management practices. Economic status or area income level. Activities such as municipal street sweeping, beach cleaning and preventing high discharge surface runoff [46].

6.1 Management of Marine Waste Plastic Similar to other conservational difficulties, aquatic wreckage can be prohibited and meticulous through an operative association of education, regulation, and invention. Every person desire to take concern aimed at their activities and preserve their garbage out of aquatic location as of school kids, to individuals who eat fast-food; leisure boaters and viable fisher-men; seaside companies and marina machinists; leftover managing employees and labours in entire manufacturing which transference or building resin pills. Information is significantly aimed at regulars to style suitable adoptions when it comes to by means of and setting of leftover substances. Informative constituents have also been formed aimed at several viewers through Ocean Conservancy, U.S. National Oceanic and Atmospheric Administration, U.S. Environmental Protection Agency, U.S. Coast Guard, United Nations Environmental Programme and countless additional management interventions and non-profit establishments. Participants together with resident peoples; management, interventions, and system; administrations; foundations; productions and manufacturing must be elaborate in exertion to efficiently decrease and governor aquatic fragments and its conservational influences. Businesses associated through these products and amenities must obligate to enchanting on an accountable character in wreckage administration and decline. Only through their immersion and provision can generate operative resolutions to wreckage problematic [47]. The plastic business has reserved stages to recognize the accurate nature of robust and degradable plastic constituents and behaviours in the atmosphere. The northwestern Hawaiian Islands aimed at Memorial description and has operated through Ocean Futures and Jean-Michel Cousteau on an education movement on aquatic fragments. Additional corporations similar to ITW Hi-Cone and Philip Morris USA have straight advanced their clients through clutter inhibition communications. The United Nations Convention on the Law of the Sea, 1982 (UNCLOS 1982) sets out not only regulations for the planning of national sovereignty waters, waters under jurisdiction, and freedoms of navigation, but also regulations for preventing marine pollution and conserving marine species [48].

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Managements have resisted aimed at eras to decrease aquatic plastic fragments [49]. One hundred thirty-four nations decided to disregard plastics dumping at aquatic. The investigation has exposed that problematic of aquatic fragments has degenerated subsequently MARPOL 73/78 was contracted. This might be due to aquatic fragments problematic is correlated to inappropriate dumping of leftover on land-living. Several non-governmental organizations (NGOs) deportment monitoring investigation on aquatic fragments to rise responsiveness [50]. For illustration, 5 Gyres Institute and Joint Group of Experts on Scientific Aspects of Marine Environmental Protection involve in responsiveness movements. Ocean Conservancy manages International Coastal Clean-up (ICC). ICC inspires additional NGOs and helper assemblies to participate in justifying aquatic fragments through cleaning up seaside extents crosswise sphere. Honolulu Policy summaries policies aimed at inhibition and organization of aquatic fragments. [51]. Honolulu Policy has been improved crosswise sphere to encounter definite requirements of diverse sections like Canada and U.S. [52].

7 Conclusions Healthcare leftover has several difficulties connected, and an obligation to invention suitable explanations either through organization policies or technical interferences occur. Growing measures of leftover generated imitate developments in our healthcare organizations, accommodations, and significances. Unquestionably, a quick elevation of HCW managing policies is dynamic to manage through this rise and preserve an innocuous atmosphere. HCW extends crosswise an extensive variety as of benevolent recyclables to transmittable pointers demanding a flawless combination of managing policies and skills to handle them. However, the segment of communicable leftover is in the direction of 10% a minor slipup might make total leftover transferable. Therefore, estimate additional exertions and possessions. Biodegradability corroboration norms below composting circumstances like verge proportions of biodegradation and disintegration, period, temperature, and ecotoxicity have been offered aimed at key rules and typical testing procedures. Constructed on those diverse rules and their contented an incline of spectacles and practical supplies which might be improved to encounter grange composting situations aimed at farming compostable plastics is projected. These supplies might be used as norms of creation of an innovative integrative rule aimed at compostable plastics used in farming submissions. High proportion and high moistness contented of nutrition leftover in household leftover are key restrictive features in the repossession of recyclables and chief givers to high rate and low effectiveness of leftover dumping. Conventional household leftover organization scheme that is created on an innovative foundation parting process is a rate operative organization. It might be stretched to complete biosphere. Regardless of investigation on reasons of aquatic fragments and exertions to teach individuals about requirement aimed at anticipation. All investors

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must be devoted to the construction of approaches and occasions which inspire individuals to decrease aquatic fragments. We must endure through present exertions via administrations and remote area to increase consciousness, create fragments reduction plans, and transformation behaviours.

8 Recommendations Waste plastic is very harmful for humans as well as environment. The occurrence of plastics in the environment whether as macro-plastic wreckage or as micro-plastics has extensively been recognized as a universal problem. So, management of waste plastic i.e. healthcare waste, soil, household plastic, marine plastic is very important.

References 1. Ray, A. (2008). Waste management in developing Asia: Can trade and cooperation help?, The. Journal of Environment and Development, 17, 3–25. 2. Elias, A., & Scott, A. (2018). Plastics in the ocean. Encyclopedia of the Anthropocene, 1, 133–149. 3. Richard, T. C., & Napper, E. I. (2018). Microplastics in the environment. Plastics and the Environment, 47, 60 4. Sawada, H. (1998). ISO standard activities in standardization of biodegradability of plastics— development of test methods and definitions. Polymer Degradation and Stability, 59, 365–370. 5. Geyer, R., Jambeck, J. R., & Law, K. L. (2017). Production, use, and fate of all plastics ever made. Science Advances, 3, e1700782. 6. Briassoulis, D., Dejean, C., & Picuno, P. (2010). Critical review of norms and standards for biodegradable agricultural plastics Part II: Composting. Journal of Polymers and the Environment, 18, 364–383. 7. Wang, X.-L., Yang, K.-K., & Wang, Y.-Z. (2003). Properties of starch blends with biodegradable polymers, Journal of Macromolecular Science, Part C. Polymer Reviews, 43, 385–409. 8. Gross, R. A., & Kalra, B. (2002). Biodegradable polymers for the environment. Science, 297, 803–807. 9. Harhay, M. O., Halpern, S. D., Harhay, J. S., & Olliaro, P. L. (2009). Health care waste management: A neglected and growing public health problem worldwide. Tropical Medicine and International Health, 14, 1414–1417. 10. Mujeeb, S. A., Adil, M. M., Altaf, A., Hutin, Y., & Luby, S. (2003). Recycling of injection equipment in Pakistan. Infection Control and Hospital Epidemiology, 24, 145–146. 11. Ananth, A. P., Prashanthini, V., & Visvanathan, C. (2010). Healthcare waste management in Asia. Waste Management, 30, 154–161. 12. Adamcová, D., Zloch, J., Brtnický, M., & Vaverková, M. D. (2019). Biodegradation/Disintegration of Selected Range of Polymers: Impact on the Compost Quality. Journal of Polymers and the Environment, 27, 892–899. 13. Mukherjee, A., Knoch, S., Chouinard, G., Tavares, J. R., & Dumont, M.-J. (2019). Use of biobased polymers in agricultural exclusion nets: A perspective. Biosystems Engineering, 180, 121–145. 14. Briassoulis, D., Hiskakis, M., Scarascia, G., Picuno, P., Delgado, C., & Dejean, C. (2010). Labeling scheme for agricultural plastic wastes in Europe. Quality Assurance and Safety of Crops and Foods, 2, 93–104.

Management of Waste Plastic: Conversion and Its Degradation …

247

15. Hiskakis, M., Babou, E., Briassoulis, D., Marseglia, A., Godosi, Z., Liantzas, K. (2008). Recycling specs for agricultural plastic waste (APW)-a pilot test in Greece and in Italy, Agricultural and biosystems engineering for a sustainable world. In International conference on agricultural engineering. European Society of Agricultural Engineers (AgEng). 16. Briassoulis, D., Babou, E., & Hiskakis, M. (2011). Degradation behaviour and field performance of experimental biodegradable drip irrigation systems. Journal of Polymers and the Environment, 19, 341–361. 17. Briassoulis, D., & Dejean, C. (2010). Critical Review of Norms and Standards for Biodegradable Agricultural Plastics Part I. Biodegradation in Soil. Journal of Polymers and the Environment, 18, 384–400. 18. Hogland, W. (1996). Landfill mining in Europe and USA: the state of the art. In Proceedings, WASTECON’96. Durban, South Africa. 19. Savage, G. M. (1993). Landfill mining: past and present. Biocycle. 20. Spencer, R. (1991). Mining landfills for recyclables. BioCycle; (United States), 32. 21. Hogland, W., Marques, M., & Nimmermark, S. (2004). Landfill mining and waste characterization: A strategy for remediation of contaminated areas. Journal of Material Cycles and Waste Management, 6, 119–124. 22. Cha, M. (1997). Mining and remediation works at ulsan land fill site, Korea. In Proceedings Sardinia 00, sixth international landfill symposium (pp. 553–558). Sardinia, Cagliari. 23. Kumar, A., & Samadder, S. (2017). A review on technological options of waste to energy for effective management of municipal solid waste. Waste Management, 69, 407–422. 24. Hou, D., Al-Tabbaa, A., Guthrie, P., Watanabe, K. (2012). Sustainable waste and materials management: National policy and global perspective. ACS Publications. 25. Tai, J., Zhang, W., Che, Y., & Feng, D. (2011). Municipal solid waste source-separated collection in China: A comparative analysis. Waste Management, 31, 1673–1682. 26. Hoornweg, D., & Bhada-Tata, P. (2012). What a waste: a global review of solid waste management. 27. Ouda, O., Raza, S., Nizami, A., Rehan, M., Al-Waked, R., & Korres, N. (2016). Waste to energy potential: A case study of Saudi Arabia. Renewable and Sustainable Energy Reviews, 61, 328–340. 28. Kumar, A., & Samadder, S. (2017). An empirical model for prediction of household solid waste generation rate–A case study of Dhanbad, India. Waste Management, 68, 3–15. 29. Fazeli, A., Bakhtvar, F., Jahanshaloo, L., Sidik, N. A. C., & Bayat, A. E. (2016). Malaysia’s stand on municipal solid waste conversion to energy: A review. Renewable and Sustainable Energy Reviews, 58, 1007–1016. 30. Khan, D., Kumar, A., & Samadder, S. (2016). Impact of socioeconomic status on municipal solid waste generation rate. Waste Management, 49, 15–25. 31. Gu, B., Wang, H., Chen, Z., Jiang, S., Zhu, W., Liu, M., Chen, Y., Wu, Y., He, S., & Cheng, R. (2015). Characterization, quantification and management of household solid waste: A case study in China. Resources, Conservation and Recycling, 98, 67–75. 32. Shafiee, S., & Topal, E. (2009). When will fossil fuel reserves be diminished? Energy Policy, 37, 181–189. 33. Baji´c, B. Ž, Dodi´c, S. N., Vuˇcurovi´c, D. G., Dodi´c, J. M., & Grahovac, J. A. (2015). Waste-toenergy status in Serbia. Renewable and Sustainable Energy Reviews, 50, 1437–1444. 34. Kalyani, K. A., & Pandey, K. K. (2014). Waste to energy status in India: A short review. Renewable and Sustainable Energy Reviews, 31, 113–120. 35. Ali, G., Nitivattananon, V., Abbas, S., & Sabir, M. (2012). Green waste to biogas: Renewable energy possibilities for Thailand’s green markets. Renewable and Sustainable Energy Reviews, 16, 5423–5429. 36. Achillas, C., Vlachokostas, C., Moussiopoulos, N., Banias, G., Kafetzopoulos, G., & Karagiannidis, A. (2011). Social acceptance for the development of a waste-to-energy plant in an urban area. Resources, Conservation and Recycling, 55, 857–863. 37. Arafat, H. A., Jijakli, K., & Ahsan, A. (2015). Environmental performance and energy recovery potential of five processes for municipal solid waste treatment. Journal of Cleaner Production, 105, 233–240.

248

Pratibha et al.

38. Shekdar, A. V. (2009). Sustainable solid waste management: An integrated approach for Asian countries. Waste management, 29, 1438–1448. 39. Godfrey, L. (2019). Waste plastic, the challenge facing developing countries—ban it, change it, collect it? Recycling, 4(1), 3. 40. Thomas, C. K., & Fullerton, D. (2017). Garbage, recycling, and illicit burning or dumping (pp. 81–94). Routledge. 41. Jenkins, R. R. (1993). The economics of solid waste reduction. Books. 42. Hong, S., Adams, R. M., & Love, H. A. (1993). An economic analysis of household recycling of solid wastes: The case of Portland. Oregon, Journal of Environmental Economics and Management, 25, 136–146. 43. Ayeleru, O. O., Dlova, S., Akinribide, O. J., Ntuli, F., Kupolati, W. K., & Marina, P. F., et al. (2020). Challenges of plastic waste generation and management in sub-Saharan Africa: A review. Waste Management, 110, 24–42. 44. Horton, A. A., Walton, A., Spurgeon, D. J., Lahive, E., & Svendsen, C. (2017). Microplastics in freshwater and terrestrial environments: Evaluating the current understanding to identify the knowledge gaps and future research priorities. Science of the Total Environment, 586, 127–141. 45. U.N.E.P.D.o.E. (2011). Warning, Assessment, UNEP Year Book 2011: Emerging Issues in Our Global Environment, UNEP/Earthprint. 46. Egede, E. (2016). Institutional gaps in the 2050 Africa’s Integrated Maritime Strategy. Iilwandle Zethu: Journal of Ocean Law and Governance in Africa, 2016, 1–27. 47. Jambeck, J. R., Geyer, R., Wilcox, C., Siegler, T. R., Perryman, M., Andrady, A., Narayan, R., & Law, K. L. (2015). Plastic waste inputs from land into the ocean. Science, 347, 768–771. 48. Ghayebzadeh, M., Aslani, H., Taghipour, H., & Mousavi, S. (2020). Estimation of plastic waste inputs from land into the Caspian Sea: A significant unseen marine pollution. Marine Pollution Bulletin, 151, 110871 49. Sheavly, S., & Register, K. (2007). Marine debris and plastics: Environmental concerns, sources, impacts and solutions. Journal of Polymers and The Environment, 15, 301–305. 50. Van Truong, N., & BeiPing, C. (2019). Plastic marine debris: Sources, impacts and management. International Journal of Environmental Studies, 76(6), 953–973. 51. Rochman, C. M., Kross, S. M., Armstrong, J. B., Bogan, M. T., Darling, E. S., Green, S. J., Smyth, A. R., & Veríssimo, D. (2015). Scientific evidence supports a ban on microbeads. ACS Publications. 52. Pettipas, S., Bernier, M., & Walker, T. R. (2016). A Canadian policy framework to mitigate plastic marine pollution. Marine Policy, 68, 117–122. 53. Xanthos, D., & Walker, T. R. (2017). International policies to reduce plastic marine pollution from single-use plastics (plastic bags and microbeads): A review. Marine Pollution Bulletin, 118, 17–26.

Gold Phytomining in India: An Approach to Circular Economy in the 21st Century Sahendra Singh

Abstract Phytomining technology refers to the process of recovery of gold and the other usable metals from the tailings and waste dumps. The process represents a paradigm shift in the context of the waste materials being converted into the valuable products [21]. Gold phytomining is the process of extraction of gold from these waste materials/dumps to yield an economic profit. The idea of gold phytomining is being worked upon by the various scientific groups throughout the world [12, 18, 20]. Many plant species are being evaluated for their potential for the gold phytomining under the field and laboratory conditions. Since it is difficult to recover 100% of gold hosted in the minerals by conventional technology, the gold lying in the tailing dumps and waste rock piles in the mining areas around the world is wasted. The recovery of this gold using plant species is considered as a viable alternative, since the extraction or removal of gold from the tailings and waste dumps is not possible with the present state of technology. These waste dumps, and tailing sites are an environmental risk to the ecosystem. The secondary dispersion of the waste generated by the mining industry, facilitated by air and water causes a concentration of heavy metals such as arsenic, copper, and mercury and hence are a potential threat to the ecosystem. The huge cost associated with the processing of tailing and waste dumps by conventional technology needs to be relooked upon for alternative innovative biological technologies to remove and intoxicate the pollutants. Keywords Phytomining · Gold · Ecosystem · Mining industry · Tailings

1 Introduction Gold mining is an integral part of the mining industry in every continent of the world except Antarctica. The gold market is huge and complex and hence is shipped to the different parts of the world for refining or sold to the various end-users. Since gold is valuable and resistant, it has a considerable potential recycling market and is S. Singh (B) Department of Applied Geology, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand, India e-mail: [email protected] © Springer Nature Switzerland AG 2022 S. Yadav et al. (eds.), Environmental Management in India: Waste to Wealth, https://doi.org/10.1007/978-3-030-93897-0_12

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constantly being transported around the world. It is also being refined and re-smelted for different products by different end-users. India imports approximately 950 tonnes of gold per year from the international gold market and presently has a share of 25% in the global gold import after China. This has been projected to increase by 36% by 2050 (World Gold Council). The existing scenario requires a relook in our national gold exploration policy so that gold production can be increased, and the import proportion can be brought down to save the foreign currency. Presently the gold production of our country is only 2% of the total annual gold consumption of our country. Therefore, we need to find out an innovative way to increase our gold production status. India has a long history of gold mining and also has a large resource of sites of low-grade gold concentration suitable for gold phytomining [28]. The increase in the gold price in the international market during the first decade of the twenty-first century led to further research related to the gold concentration and yield of a range of plant species. These studies suggest that gold phytomining can be an economically viable technology in the future. This work presents a review of the prospects and potential of gold phytomining in India, especially in the given national scenario of high import figure of gold and very low in-house gold production. The environmental management of left out mining areas is a global issue and is prevalent in many parts of India in the absence of proper statutory regulations and its coherent implementation. This approach provides an added advantage to control the deteriorating environmental condition in many mining regions of our country. Application of this technology will also create the employment of local people in the agricultural activities and the activities related to the management of contaminated sites. This is compatible with the concept of a circular economy [25].

2 Gold Phytomining Gold is immobile and non-soluble in soils, and hence can only be extracted from minerals and soils by cyanogenic plants and by microbial activity [8, 22, 27, 29]. It can be further dissolved in organic compounds, which are produced by bacteria during their metabolic activities. Previous workers were able to isolate bacteria from gold deposits that released a considerable amount of aspartic and glutamic acids [15, 24]. Other organic metabolites such as nucleic, pyruvic, lactic, oxalic, formic and acetic acid were also released into the environment to form stable complexes with gold [9]. The gold incorporation into the plants is a complex mechanism and involves several steps starting from the movement of metal from the soil into the root, and further to the shoots followed by the detoxification and sequestration [26]. It is possible to extracts gold from low-grade gold deposits, overburdens, and tailings. However, the most important aspects are the identification of auriferous rocks/soil. The use of synthetic chelates to the soil is the most common methods for soil-bound metal extraction. There are disadvantages associated with the usage of synthetic chelates in phytomining of gold, i.e., it can pollute the environment [23].

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2.1 Gold Phytomining—Indian Scenario and an Approach to the Circular Economy India is known as a land of gold since the ancient period. The gold mining industry in India began 400 years ago. In 1905, India was amongst the top ten gold producing countries of the world. Currently, India possesses gold producing fields, which are mostly restricted to the greenstone belt of southern India, apart from a few deposits in the eastern India. As per state-wise occurrences, the primary gold resources are located in Karnataka, Jharkhand, Rajasthan, Andhra Pradesh, West Bengal, Madhya Pradesh and Chhattisgarh (Fig. 1). In terms of metal content, Karnataka has the richest ores deposits followed by Rajasthan, West Bengal, Jharkhand, Andhra Pradesh, etc.

Fig. 1 Gold occurrences in India [3]

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During the end of the nineteenth century, a gold boom was discovered in Wyand Gold Field of southern India. Along with this many gold mines were opened up in South India, i.e. Kolar, Hutti, Gadag, Ramgiri and Honall, etc. and a few in Jharkhand such as Lawa, Mayasera, Pahardia, Kunderkocha, etc. Both primary and secondary gold occurrences belong to the peninsular and extra peninsular India, although major primary occurrences are restricted to the peninsular shield [3]. Gold deposit of primary, placer, and lateritic types were identified. However placer and lateritic types were uneconomic. According to IBM 2018 report, total reserve/resource of gold ore present in the country is 501.83 million tonnes, out of which 17.22 million tonnes were of reserve category and remaining 484.61 million tonnes were placed in resource category. Karnataka is a leader in terms of total gold content followed by Rajasthan, Andhra Pradesh, Bihar, Jharkhand, etc. Karnataka is also the leading producer of primary gold with 99% of total production. The remaining production were reported from Jharkhand (IBM 2018). Preliminary mineralogical and geochemical studies in the Sandur Schist Belt from Dharwar Supergroup indicated a new prospect for gold deposit in India. The studies carried out by National Geophysical Research Institute (NGRI) indicate high gold values in weathered surface rock samples of Banded Iron formation of Tranagar, Joga and Vibhutigudda, quartz veins and volcanic rock samples of Papinayakanahalli and Sujigudda-Murutalegudda and Greywacke of Vibhutigudda [9]. Traces were found in the greywacke of Deogiri [9]. Most of this gold is invisible and refractory. Invisible gold has also been reported from Kundarkocha, Babikundi, and Rudia area from eastern India, Hutti-Maski schist belt in southern India and Bhukia area in Rajasthan [6, 7, 14, 15]. Invisible gold occurences has received significant attention in recent years due to their unique electronic, photonic, and catalytic properties, and hence the proper understanding of the knowledge regarding the invisible gold an be helpful in the recovery of gold from such type of ores. In recent years a number of refractory gold occurrences have been reported from various part of India. These gold prospects are of low grade and difficult to process due to their refractory nature. The most significant prospects among them is the auriferous carbonaceous shale/phyllite in the eastern part of India, i.e. North Singhbhum Mobile Belt, Singhbhum Crustal province and in the western India i.e. Bhukia Jagpura prospects [16, 30]. Low-grade prospects yield a huge amount of tailings with significant gold concentration. These tailings are the ideal sites to carry out phytomining practices, which are beneficial not only to generate revenue, but will also create employment opportunities. Further, this will also help in the restoration of the ecosystem of the area. In India, gold is produced from the mines at Hutti, Uti, Hirabuddni in Karnataka, Kunderkocha, Jharkhand and as by-product from the base-metal sulphide deposits of Khetri (Rajasthan), Mosabani in East Singhbhum [6, 14, 15]. Some new gold prospects have been auctioned i.e. Lawa and Parasi (Jharkhand), Baghmara, Sonakhan greenstone belt in Chattisgarh, Anantpur in Andhra Pradesh and Gadag, Jonnagiri and Ganajor in Karnataka [3]. Gold was also recovered from secondary source by smelting of imported copper concentrates. Kolar Gold Mines (KGM), India is among the deepest gold mines in the world with a depth of about 3.2 km. Production of KGM was more than 800 tonne of gold per 51 million tonnes of ore

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in 2001. During 1881–1990, the gold production in KGF was about 47 g/t of ore while it reduces to 03.0 g/t during 1991–1999 [18]. KGF occupied almost 33 million tonnes of tailing sand containing about 24 tonnes of gold with the average gold content of 0.72 g/t [11]. Ever since the production of gold started systematically and in large scale, the mine wastes have been stacked in huge piles at various locations of the leasehold area. Because of lesser gold content, the volume of waste increased continuously; thus, occupying 15–20% of the total leasehold area. Though India is lagging in terms of the discovery of high-grade gold deposits, lowgrade gold deposits are plenty in various cratons in different part of India. Geological Survey of India (GSI) and other exploration agencies have ongoing gold exploration programs in these cratons, and many low-grade deposits have been discovered in the Dharwar, Central Indian craton (CIC), Singbhum crustal province and Aravali in Rajasthan. Recently Baghmara gold deposit near Raipur in central India has been auctioned for the mining. Parasi, Lawa & Pahardiha gold deposits in Jharkhand and the Anantpur gold prospects in Andhra Pradesh have already been auctioned for the mining lease. All these deposits are of low grade and hence the processing of ore in all these deposits is going to pile a huge tailing dump. These dumps are an ideal site for gold phytomining. This gold phytomining technology is important both for the gold production and the environmental issues, which can be addressed by these technologies. The era of gold production from refractory ore is a significant development, and the prospects of refractory ores have not been explored in all these areas. These refractory ores have even higher potential to generate huge tailing dumps, which can be tapped for gold phytomining in future. Considering these facts, discovery of many low-grade gold deposits will ultimately prove to be a blessing in disguise, and increases the prospects of gold phytomining in these areas. The mining areas in India are also suffering from the poor socio-economic condition due to the lack of an alternative option for daily subsistence living, once the mining activities are over due to mine closure. The management of abandoned mining areas is an issue, which is to be dealt with some non-conventional technological applications. The adoption of this technology may generate employment opportunities for the local community in the agriculture sector. It may further supplement the effort to manage the contaminated sites for a clean and sustainable environment.

3 Discussion Phytomining is the in-situ extraction of precious metal particles from tailing, soil, or waste dump. The total volume of mine tailings being generated globally is about 18 billion m3 /year, and it is expected to double in the next 20–30 years [2]. Tailing of gold mines contains low-grade residual gold. Gold is in non-bioavailable form and cannot be accumulated by plants under normal conditions. However, gold can be extracted by hyperaccumulation. The amount of gold that can be taken up by a plant depends on the gold concentration in the soil. Application of chelates for the uptake of metal is widely explored by the scientific fraternity. Potential of various chelating agents for

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gold is sodium cyanide, ammonium thiocyanate, ammonium thiosulphate, sodium thiocyanate, etc. During gold hyper-accumulation, the geochemistry of the substrate determines the choice of the solubilizing agent. Indian mustard (Brassica juncea) was induced with ammonium thiocyanate at different rates in pots containing artificial gold-rich material. Hyper-accumulation of gold was obtained in a thiocyanate treatment level of 160 mg/kg and yielded up to 57 mg/kg gold and with B. juncea grown in a medium containing 05 mg/kg of gold and treated with ammonium thiocyanate. In case of low pH sulphide tailings ammonium thiocyanate is used, while for high pH unoxidized sulphide tailings, ammonium thiosulphate is used as a chelating agent. As per [1], roughly 02 mg of gold per kg of soil is needed to be required to collect 100 mg of gold in 01 kg of plant dry mass. Gold accumulation has been analysed in carrot, red-beet, onion, and two cultivars of radish, grown in an artificial gold substrate [19]. Chilopsis linearis has been reported as a potential plant for gold phytomining [5]. Phytoextraction can be used as an eco-friendly and economically profitable technique to extract low-grade gold and precious group of metals. Hyper accumulators extract metals from the metalliferous soils and transport them to biomass above the ground. Once the crops are ready, the soil is treated with a chemical to solubilize the gold. The low-grade ore deposits are scattered throughout the world and support a wide range of plant species [13]. Metals and other inorganic contents are common forms of contamination found at waste sites, and their remediation is technically very difficult, which involves high risks during the excavation, handling, transport, longterm monitoring, and their maintenance. These techniques are suitable for smaller areas, where rapid and complete elimination of contamination is essential [10].

4 Conclusions Though India is a minor producer of gold, it has a tremendous domestic demand and a stable market for gold consumption. There is a further increase in the demand from ornamental and electronic sectors. The huge gold demand makes India the largest importer country of gold in the world. India is not enriched with a large gold deposit and with the closure of Kolar gold mines (with effect from 1.3.2001, due to deep mining and depletion of gold reserves), India is now a minor producer of gold. Though there is an increase in the primary gold production during 2016–2017, i.e. increased by 3% compared to the previous year. Currently, there are only two major working mines with few small scale gold producing mine in India [21]. The present and near-future production of gold will not be able to meet the ever-increasing demand, and hence, alternate source for gold is required to reduce the gap between production and demand. In view of the present scenario of the huge gap between gold production and demand, gold phytomining is an economically viable alternative and environmentally friendly technology to fulfil the gold requirement of India.

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5 Recommendations In the existing scenario of widening gap between the gold production and its huge demand in India, phytomining may be a viable option to bridge this gap to some extent in order to minimize the gold import of our country. Acknowledgements The author is thankful to Director IIT(ISM) for his permission to publish the manuscript. The author is also thankful to Mr. Rajarshi chakravarti, SRF, IIT(ISM) and Mr. Anmol Barla, JRF for their help and cooperation during the preparation of this manuscript.

References 1. Anderson, C. W. N., Brooks, R. R., Stewart, R., & Simcock, R. (1998) Gold uptake by plants. Gold Bulletin, 32, 48–51. 2. Aswathanarayana, U. (2003). Mineral resources management and the environment. Balkema Publication, Tokyo. 3. Deb, M. (2014). Precambrian geodynamics and metallogeny of the Indian shield. Ore Geology Reviews, 57, 1–28. 4. Deditius, A. P., Utsunomiya, S., Renock, D., Ewing, R. C., Ramana, C. V., Becker, U., & Kesler, S. E. (2008). A proposed new type of arsenian pyrite: Composition, nanostructure and geological significance. Geochimica et Cosmochimica Acta, 72, 2919–2933. 5. Gardea-Torresdey, J. L., Parsons, J. G., Peralta-Videa, J. R., & Cruz-Jimenez, G. (2005) Use of ICP and XAS to determine the enhancement of gold phytoextraction by Chilopsis linearis using thiocyanate as a complexing agent. Analytical and Bioanalytical Chemistry 382, 347–352. 6. Jha, V., Singh, S., & Venkatesh, A. S. (2015). Invisible Gold occurrence within the quartz reef pyrite of Babaikundi area, North Singhbhum Fold and Thrust Belt, Eastern Indian Shield: Evidences From Petrographic, SEM And EPMA Studies. Ore Geology Reviews, 65, 426–432. 7. Khatun, M., & Singh, S. (2017). Petrographic and ore microscopic study of carbonaceous host rocks and associated gold mineralization within Dalma volcano-sedimentary basin, North Singhbhum Mobile Belt, Eastern Indian Craton. Journal of Geoscience Research, 1, 35–41. 8. Korobushkina, E. D., Karavaiko, G. I., & Korobushkin I. M. (1983). Biochemistry of gold. In R. Hallberg (Ed.), Environmental biogeochemistry ecology bulletin (Vol. 35). Oikos Editorial Office, Stockholm. 9. Kuesel, K., Wagner, C., & Drake, H. L. (1999). Enumeration and metabolic product profiles of the anaerobic microflora in the mineral soil and litter of beech forest. FEMS Microbiology Ecology, 29, 91–105. 10. Manikyamba, C., Naqvi, S. M., Moeen, S., Rao, G. T., Balaram, V., Ramesh, S. L., & Reddy G. L. N. (1997) Geochemical heterogeneities of metagraywackes from the Sandur schist belt: implications for active plate margin processes. Precambrian Research, 84(3–4), 117–138. 11. Martin, I., & Bardos, P. (1996). A review of full scale treatment technologies for the remediation of contaminated land. EPP Publications. 12. Mohan, B. S. (2005). Phytomining of gold. Current Science, 88(2005), 1021–1022. 13. Msuya, F. A., Brooks, R. R., & Anderson, C. W. N. (2000). Chemically-induced uptake of gold by root crops: Its significance for phytomining. Gold Bulletin, 33, 134–137. http://www.portal. gsi.gov.in. Retrieved February 12 2014.

256

S. Singh

14. Robinson, B. H., Chiarucci, A., Brooks, R. R., Petit, D., Kirkman, J. H., Gregg, P. E. H., & de Dominicis, V. (1997). The nickel hyperaccumulator plant Alyssum bertoloni as a potential agent for phytoremediation and phytomining. Journal Geochemistry Exploration, 60, 115–126. 15. Saha, I., & Venkatesh, A. S. (2002). Invisible gold within sulfides from Archean Hutti-Maski schist belt, Southern India. Journal of Asian Earth Science, 20, 449–457. 16. Sahoo, P. R., & Venkatesh, A. S. (2014). ‘Indicator’ carbonaceous phyllite/graphitic schist in the Archean Kundarkocha gold deposit, Singhbhum orogenic belt, eastern India: Implications for gold mineralization vis a vis organic matter. Journal of Earth System Science, 123, 1693–1703. 17. Savvaidis, I., Karamushka, V. I., Lee, H., & Trevors, J. T. (1998). Micro-organism-gold interactions. BioMetals, 11, 69–78. 18. Sheoran, V., Sheoran, A. S., & Poonia, P. (2009). Phytomining: A review. Minerals Engineering, 22, 1007–1019. 19. Subbaraman J. V. (2006) Scope for geobotanical prospecting for gold in Karnataka and Andhra Pradesh. Current Science, 90, 750 20 Wilson-Corral, V., Anderson, C., Rodriguez-Lopez, M., Arenas-Vargas, M., & Lopez-Perez, J. (2011). Phytoextraction of gold and copper from mine tailings with Helianthus annus L. and Kalanchoe serrata L. Minerals Engineering, 24, 1488–1494. 21. Chaney, R. L., Baker, A. J. M., Morel, J. L. (2021). The long road to developing agromining/phytomining. In A. van der Ent, A. J. Baker, G. Echevarria, M. O. Simonnot, & J. L. Morel (Eds.), Agromining: Farming for metals. mineral resource reviews. Springer. https:// doi.org/10.1007/978-3-030-58904-2_1 22. Li, C., Ji, X., & Luo, X. (2020). Visualizing hotspots and future trends in phytomining research through scientometrics. Sustainabilit, 12(11), 4593. https://doi.org/10.3390/su12114593 23. Novo, L. A. B., Castro, P. M. L., Alvarenga, P., & da Silva, E. F. (2017) Phytomining of rare and valuable metals. In A. Ansari, S. Gill, R. R. Gill, G. Lanza, & L. Newman (Eds.), Phytoremediation. Springer. https://doi.org/10.1007/978-3-319-52381-1_18. 24. Jally, B., Laubie, B., Tang, Y. T., & Simonnot, M. O. (2021). Processing of plants to products: gold, REEs and other elements. In A. van der Ent, A. J. Baker, G. Echevarria, M. O. Simonnot. & J. L. Morel (Eds.), Agromining: Farming for metals. mineral resource reviews. Springer. https:// doi.org/10.1007/978-3-030-58904-2_4 25. Pons, M. N., Rodrigues, J., & Simonnot, M. O. (2021) Life cycle assessment and ecosystem services of agromining. In A. van der Ent, A. J. Baker, G. Echevarria, M. O. Simonnot, & J. L. Morel (Eds.), Agromining: Farming for metals. mineral resource reviews. Springer. https:// doi.org/10.1007/978-3-030-58904-2_5 26. Krisnayanti, B. D., Anderson, C. W. N., Sukartono, S., Afandi, Y., Suheri, H., & Ekawanti, A. (2016). Phytomining for artisanal gold mine tailings management. Minerals, 6, 84. https://doi. org/10.3390/min6030084 27. Morel, J. L., Simonnot, M. O., Echevarria, G., van der Ent, A., & Baker, A. J. M. (2021) Conclusions and outlook for agromining. In A. van der Ent, A. J. Baker, G. Echevarria, M. O. Simonnot,& J. L. Morel (Eds.), Agromining: Farming for metals. mineral resource reviews. Springer. https://doi.org/10.1007/978-3-030-58904-2_25 28. Keshavarzi, M., Davoodi, D., & Pourseyedi, S. (2018). The effects of three types of alfalfa plants (Medicago sativa) on the biosynthesis of gold nanoparticles: An insight into phytomining. Gold Bulletin, 51, 99–110. https://doi.org/10.1007/s13404-018-0237-0 29. van der Ent A., Purwadi I., Harris H. H., Kopittke P. M., Przybyłowicz W. J., MesjaszPrzybyłowicz J. (2021). Methods for visualizing elemental distribution in hyperaccumulator plants. In A. van der Ent, A. J. Baker, G. Echevarria, M. O. Simonnot, & J. L. Morel (Eds.), Agromining: Farming for metals. mineral resource reviews. Springer. https://doi.org/10.1007/ 978-3-030-58904-2_10 30. Maluckov, B. S. (2015). Bioassisted Phytomining of Gold. JOM Journal of the Minerals Metals and Materials Society, 67, 1075–1078. https://doi.org/10.1007/s11837-015-1329-4

Gold Phytomining in India: An Approach to Circular Economy in the 21st Century

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31. Nkrumah P. N., Chaney R. L., & Morel J. L. (2021) Agronomy of ‘Metal Crops’ used in agromining. In A. van der Ent, A. J. Baker, G. Echevarria, M. O. & Simonnot, J. L. Morel (Eds.), Agromining: Farming for metals. mineral resource reviews. Springer. https://doi.org/ 10.1007/978-3-030-58904-2_2 32. Barla, A., Singh, S., & Chakravarti, R. (2020). Genesis of metasomatic gold mineralization in the Pahardiha-Rungikocha gold deposit, eastern India: Constraints from trace element signatures in chromite-cored magnetite and bulk rock geochemistry. Ore Geology Reviews, 121, 103482.

Conclusions

Update, Conclusions and Recommendations for “Environment Management: Waste to Wealth in India” Abdelazim M. Negm, El-Sayed E. Omran, Shalini Yadav, and Ram Narayan Yadava

Abstract This chapter casts light on the main conclusions and recommendations of the 13 chapters presented in the book titled “Environment Management: Waste to Wealth in India”. In addition, some findings from a few recently published research work related to environmental management. Therefore, this chapter contains information on waste to wealth in India, waste to energy and waste and sustainability. In addition, a set of recommendations for future research work is pointed out to direct future research towards environmental management, which is the main subject of strategic importance under Indian circumstances. Keywords Environment · Management · Waste · India · Wealth · Energy · Sustainability

1 Background More than 75% of the waste we produce is recyclable, but in India recycle just 30% in India. It’s time for the country to wake up and start addressing waste management seriously because if this problem is further neglected, then by 2030 we will need a landfill as large as Bengaluru to dump all the waste. According to the Central Pollution A. M. Negm (B) Water and Water Structures Engineering Department Faculty of Engineering, Zagazig University, Zagazig 44519, Egypt e-mail: [email protected] E.-S. E. Omran Institute of African Research and Studies and Nile Basin Countries, Aswan University, Aswan, Egypt Soil and Water Department, Faculty of Agriculture, Suez Canal University, Ismailia 41522, Egypt S. Yadav Department of Civil Engineering Rabindranath Tagore University, Bhopal 41522, MP, India R. N. Yadava Research and International Affairs, Madhyanchal Professional University, Bhopal, Madhya Pradesh, India © Springer Nature Switzerland AG 2022 S. Yadav et al. (eds.), Environmental Management in India: Waste to Wealth, https://doi.org/10.1007/978-3-030-93897-0_13

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Control Board in India, less than 15 percent of the municipal solid waste produced is collected or treated (https://www.dnaindia.com/delhi/report-delhi-government-putspollution-onus-on-civic-bodies-2679037). Numerous problems are plaguing effective waste management in India, ranging from lack of proper guidelines, authorities planning, inadequate waste collection, and treatment to a lack of citizens ’ knowledge of waste segregation. Further information about Indian agenda 2030 concerning waste management could be found in the first chapter titled “Waste Management and the Agenda 2030 in the Indian Context”. Therefore, this chapter presents general conclusions of environmental management and its importance for India and the researchers. In designing sustainable environmental management, it is necessary to give due consideration to various resources used, which render the resultant production system unsustainable. So, the book intends to improve and address the following main theme: – From Waste to Wealth – From Waste to Energy – Waste and Sustainability. The next section presents a brief of the important findings of some of the recent (updated) published studies on environmental management, then the book chapters’ main conclusions, and the main recommendations for researchers and decisionmakers are presented. The update, conclusions, and recommendations presented in this chapter come from the data presented in this book.

2 Update The following are the major update for the book project based on the main book theme. From Waste to Wealth. Five approaches were identified for environmental management. The first approach is through solid waste management methods: A technological analysis of mechanical, chemical, thermal, and hybrid means. Major Indian cities such as Ahmedabad, Hyderabad, Bangalore, Chennai, Kolkata, Delhi, and Mumbai produce about 2300, 4200, 3700, 4500, 3670, 5800 and 6500 tons of solid waste per day, respectively [1]. This enormous amount of solid waste produced varies in its properties and composition depending on the location of the waste production, climatic conditions, living standards of the citizens, etc [2]. The massive volume of irrecoverable nd/or non-reusable solid waste needs specific treatment methods and procedures in order to handle it effectively [3]. Methods of management such as shredding seek to minimize the amount of solid waste produced, and the immobilization of harmful substances contained in solid waste are accomplished by methods e.g. stabilization. The idea of waste to energy is gaining more attention recently because of the enormous energy harnessing potential of the major portion of the solid waste produced [4]).

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The second potential approach identified is the characterization and sustainable utilization of steel slag (SS) as recycled aggregates in the Indian concrete industry. Technological developments have improved human life considerably but at the expense of producing many by-products and waste. One such by-product is Steel Slag (SS) produced from Iron and Steel Plants, which in India poses a significant economic and environmental burden. During the production of liquid steel; almost 150–180 kg of slag is produced for each ton of crude steel, depending on the nature of the hot metal and steel-making process [5]. The SS is mainly used in the manufacture of cement clinker, portland slag, road metal and bases, asphalt paving, track ballast, landfills, waste site and concrete aggregates barrier material remedy, road building, railway ballast, paving bases, and patching route gaps, etc. [6]. The third potential approach identified is the application of green synthesis of nanoparticles for the removal of heavy metal ion from industrial wastewater. Heavy metals are the naturally occurring elements on the earth’s crust that have a comparatively higher atomic weight and density [6]. It is said that these elements show certain toxic effects at very low levels. Bioaccumulation is the mechanism in which the heavy metals appear to migrate over time into the body of living organisms. Within the living body, the concentration of heavy metals is higher than that of the atmosphere. They continue to build up, hence the word bioaccumulation. Via the human body, these elements are excreted, but this cycle takes a great deal of time. These are transferred by the body to the excretory organs such as the kidney and liver and continue to be processed there for gradual excretion [7]. Heavy metal excretion is a very slow process and it begins destroying the organ in the process. Some forms of treatment may be adsorption, reverse osmosis, bio-sorption, etc. Reusing and recycling will reduce waste volumes. Mining, electroplating, metal smelting, etc. are industries that contribute to heavy metal ion pollution. Pollution of heavy metal ions can also be caused by natural events such as volcanic eruption and also by geological features adding up to pollution. The fourth potential approach identified is waste management in the Indian pharmaceutical industries. Different types of waste derive from different sources, such as manufacturing (e.g., pharmaceutical firms, textile manufacturers, etc.), households, agriculture (e.g., slurry), mining and quarrying, commercial activities (e.g., shops, restaurants, hospitals, etc.), and building and demolition. Pharmaceutical waste is often of different kinds, i.e. hazardous and non-hazardous waste, among these various forms of waste. The pharmaceutical industry is focused primarily on medicines that cure or prevent illnesses and diseases using scientific research and development. The pharmaceutical industries release toxic pollutants that have entered the atmosphere through various routes such as wastewater injection, sewage lines, drainage, landfill site disposal, etc. A huge quantity of waste is produced during pharmaceutical manufacturing and maintenance operations, and traces of these wastes have been found in drinking water sources and, if present for a longer period of time, cause serious health effects to be both aquatic and human [8]. The composition, magnitude and seasonal variation of waste generation can differ depending on the type of industry. Because of the adverse environmental and human health effects of synthetic products,

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India’s oldest medical care system, herbal pharmaceuticals, and cosmetic industries are getting more attention. The fifth potential approach identified is erosion management of riparian ecosystem in coal mining area through selective vegetation. Mining operations directly affect the landscape, depletion of agricultural land, forest and pasture land and indirectly affect soil degradation, air and water contamination, toxicity, geoenvironmental hazards, loss of biodiversity and eventually loss of economic prosperity. Furthermore, nutrient depletion along with water runoff and soil erosion, leading to the impoverishment of riparian land, results in a stream or river water becoming eutrophised. The riparian vegetation serves as a good nitrogen harvester from the catchment areas and manages the eutrophication of the water bodies nearby. With this, plant cover capacity varies from one species to another in that soil and water erosion by vegetation.

2.1 From Waste to Energy Four potential approaches were identified for using waste products to increase energy in India: The first potential approach identified is urban solid waste management for enhancement of agriculture productivity in India. The term municipal solid waste (MSW) represents the flux of solid waste created by food waste from households, agricultural waste, human and animal waste etc. MSW manufacturing is an unavoidable result of the consumer culture today. The rate, quantity and quality of solid municipal waste production is highly accelerated by rapid urbanization, population overburden, economic growth and higher living standards in developing countries [9]. Municipalities, typically responsible for waste management in cities, can supply the residents with a related degree with an economical and productive network [10]. The capacity is much greater given the approximately 500 L of MSW that the cities and towns here produce annually. That works out at 140,000 tons a day (tpd), with only Delhi and Mumbai contributing 9,000 tpd each, 5,000–6,000 tpd Chennai and Kolkata, and 4,000–5,000 tpd Bangalore and Hyderabad. IL&FS Environmental Infrastructure and Services Ltd. (IEISL) operates composting units at Delhi, Jalandhar, Mysore, Kozhikode, Erode, Pollachi, Mettupalayam, Udumalpet and Coonoor, process 1,480 tpd of MSW [11]. Many Indian cities have taken significant measures to introduce sustainable waste management practices by engaging the community in segregation, implementing better PPP contracts and investing in modern transport, processing and disposal infrastructure. There is also growing awareness of the role of waste pickers / informal sector in SWM. Such programs in other cities in the world have tremendous potential for broader replication. In addition, a decentralized framework will help tackle the insurmountable challenges and problems of waste management in low-income developing world cities in a way that is socially desirable, economically viable and environmentally sustainable [12]. The second potential way is the food waste utilization for the production of biogas by anaerobic digestion: a case study in coal capital of India. The demand for energy

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is rising day by day globally and is predicted to double by 2050. Because of these challenges, researchers are developing innovative approaches to efficient recycling of the organic waste to generate bioenergy, biomaterials, chemicals, etc. to balance the demand for fossil fuel and minimize landfill burdens [13]. Biogas is an enticing choice with immense potential among biomass sources, offering various invigorating potential outcomes to supplant, and thus diminishing our reliance on non-renewable energy sources. Hong Kong is a very dense city that produced 0.32 kgDay-1 per capita FW [14]. India’s major source of energy is coal and it’s going to be marginal every day. Today, multi-day biogas is one of the desirable energy sources for both rural and urban areas due to natural waste that can be efficiently measured. It uses natural waste and produces semi-solid manure and water for further use in horticultural production and decreases the effect of the nursery. Nevertheless, FW will assist the current worldwide energy demands which are fundamental parenthoods and will sensibly take on a noble job in shifting the world’s profile excess from non-renewable energy sources as a prerequisite for a sustainable energy source age [15]. Development of low-cost microbial fuel cell for converting waste to electricity and abating pollution is the third potential way. With the change in the perception of waste as an unwanted resource, the emphasis changed from waste reduction to waste use. Microbial fuel cell (MFC) was a pioneer in this regard because of its remarkable ability to turn organic matter present in waste directly into electricity. Despite the enormous improvement in power produced by laboratory-scale MFCs, traditional waste management techniques can only be replaced if their power production and manufacturing costs are made adequately competitive. The discrepancy between the theoretical and actual voltage achieved in MFCs primarily concerns overpotential losses associated with the exchange membrane (PEM) of electrodes, electrolytes and protons. Graphene and carbon nanotubes have been a rewarding discovery about electrode materials but catalyst integration will further enhance power generation in MFCs. The fourth potential way is the recent developments in energy recovery from sewage treatment plant sludge via anaerobic digestion. Biogas, a promising means for addressing global energy needs, has considerable sustainability potential because it can be produced from renewable materials available locally, such as sewage sludge [16]. At first, the primary and secondary sludge originally formed at 1–2% total solids are thickened by gravity, flotation, or belt filtration to minimize their volume to around one third of their original volume. Once this is accomplished, various methods which include anaerobic digestion (AD) as the oldest, well-developed and economically attractive method stabilize the sludge. Many countries have adopted AD of sewage sludge as the main treatment method of sludge [17]. AD is a conventional biological process in which the degradation of organic matter occurs by a variety of symbiotic microorganisms mostly. Archaea and bacteria [18] in the absence of molecular oxygen. AD of low organic waste results in lower production of biogas and a low rate of organic removal, thereby decreasing the potential gain of the process [19]. Therefore, for different reasons such as low energy requirements for heating, larger digester volume and fewer material handling needs, high solid AD (HSAD) has been recognized as advantageous over traditional anaerobic digestion (CAD). It has only

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drawn special attention recently. It deals with TS substance sludge greater than 8 percent compared to TS 2–6 percent CAD [20]. Until now very few researchers have worked on high solid sludge mono-digestion.

2.2 Waste and Sustainability Three approaches were identified for using and control waste as a potential way for sustainability. First is management of waste plastic: conversion and its degradation as an environment concern in Asian Country. Plastics are a type of artificial organic polymers collected from a high average molecular weight of extended, chain-like particles. Recyclable plastics nowadays exist in several budget divisions; agriculture is one of those divisions. In 2007, the universal extent of recyclable plastics used at the European level represented approximately 30,000 t of solitary 0.06% of 47.5 Mt universal use of plastics [21]. Nowadays, recyclable plastics are in many field divisions. Cultivation is one such division. Consistent statistics in France are 6.7 Mt of plastic for example, and 10,000 t are recyclable plastics representing 0.15% of plastics use [22]. Nowadays, recyclable polymers are increasingly being used as alternatives to plastics aimed at numerous submissions of conservative plastic cultivated exclusively for the production of cultivated films [23] and vegetable containers, staples designed for growing vegetations, webs aimed at cultivation and forestry, feedingstuffs etc. [22]. The second approach is gold phytomining in India: an approach to a circular economy in the 21st Century. India imports about 950 tons of gold per annum on the international gold market and now has a total share of 25 percent of global gold imports after China. By 2050 (World Gold Council) this was expected to increase by 36%. The current scenario needs a relook in Indian national gold exploration strategy to increase gold production, and the proportion of gold imports can be decreased to save the foreign currency. According to the IBM 2018 estimate, the total reserve/resource of gold ore in the country is 501,83 million tons, of which 17,22 million tons were of reserve category and the remaining 484,61 million tons of resource category were put. In terms of total gold content, Karnataka is a leaderled by Rajasthan, Andhra Pradesh, Bihar, Jharkhand etc. With 99% of total output, Karnataka is also the leading producer of primary gold. The rest of the output was registered from Jharkhand. The gold is always transparent and refractory. Kundarkocha, Babikundi, and Rudia area from eastern India, Hutti-Maski schist belt in southern India, and Bhukia area in Rajasthan have also registered invisible gold [24].

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3 Conclusions In the course of the current book project, numerous conclusions taken from this book were made by the editorial teams. In addition to methodological observations, the chapter draws important lessons from the book’s cases, particularly the positive features of waste. These conclusions are important to environmental management in India. These are discussed in the following in no particular order.

3.1 From Waste to Wealth There are different ways for the conversion of waste into a useful one. But activities must be performed to continue the practice in respect of sustainable development of natural resources. The benefits derived from small-scale waste recycling by students were incredible. The enactment and implementation of a policy and waste management legislation to support waste recycling and its application, political support is urgently needed if small-scale recycling programs are to succeed. Public education on the advantages of using recycled products, including environmental benefits in rural and urban areas, needs to be promoted using video shows, radio, newspapers and magazines, television programs, and public campaigns. Considering the rate of solid waste generation and the reduction of disposal space, mechanical methods may be considered before other methods for ease of transport as well as pretreatment methods. Given the reduction of solid waste volume, incineration is the safest form of treatment, reducing the volume of 90%. Whereas the highest reported amount of syngas and bio-oil were recovered with gasification and pyrolysis process, respectively. While, considering waste to the production of energy and meeting the demand for fossil fuel, gasification and pyrolysis are better combining technologies that have a lower impact on the environment than other methods. Technologies for stabilizing/neutralizing the toxic substances in the solid waste can be considered. However, the use of hybrid technologies over conventional ones makes the management process more versatile in terms of sustainability and can reduce short and long-term environmental and human health hazards. Proper implementation of the latest technologies in the solid waste management sector can play an important role in maintaining a pollution-free and sustainable environment. The different physical, chemical, mineralogical, and mechanical characteristics of Steel Slag (SS) waste were variable parameters that were influenced by sampling location and method of collections, amount of sampling, nature of waste, and manufacturing process. It was also observed that; the basic mechanical characteristics such as water absorption, abrasion value, crushing value, and impact value are within the limit of Indian standard. During the compressive strengths test of SS waste for M-20 grade cubes as per Indian standard, it was observed that the target cube strength was achieved at 28 days and was higher for 90 days. Hence SS waste can be used as a

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recycled aggregates (RA) replacing Natural Aggregates (NA) during the concrete making. An environmentally friendly solution is the use of green chemistry to substitute the conventional polymer based materials for heavy metal recuperation. It aims to optimize the use of biopolymers in manufacturing, medical, and economic concerns. There are various physical and chemical methods to remove heavy metals such as electrocoagulation, adsorption, precipitation, flocculation, etc. The heavy metal exposure also occurs through the pipes used; alum used in water treatment increases Aluminum content in water. Furthermore, the nanoparticles and Nanosorbent have high advantages for the separation of heavy metal ions. The pharmaceutical industry is one of the primary industries that saves millions of lives by producing medicines. On the other hand, it produces massive quantities of waste, whether solid or liquid, which has a negative effect on water quality and the environment and human life. For this respect a list of recovery methods has been widely used. Green management facility has been well adopted in Indian pharmaceutical industry with proper treatment of liquid waste at effluent treatment plants and solid waste management by incineration and deep burial. The riparian area, an extremely fragile and delicately balanced ecosystem is seriously degraded due to recurrent soil/water erosion that contributes to water sources being silted up. Herbaceous plant species on the riparian slopes play a significant role in linking the soil, rising water absorption, and reducing erosion and loss of nutrients. The soil, water, and nutrient loss quantity from the bare plots is several folds higher than the vegetated plots from the sloping and undulating plots. Consequently, the efficiency of conservation is more from the vegetated plots. The losses through runoff water and eroded soil were minimized from vegetated plots to a great extent compared to bare plots.

3.2 From Waste to Energy The need for the hour is to correct solid waste management practices, the technologies for eliminating and reducing waste, and optimizing the recycling and use of environmentally friendly substitute materials. Instead of landfilling or Municipal Solid Waste (MSW) incineration with the advent of modern technology, it can be utilized in agriculture as a fertilizer for plants and amendment to improve soil health. Considering that sandy soil is erodible, low water holding capacity with low organic matter and nutrient content, compost application will be a long-term investment for soil and plant safety. A module of this type for the recovery of valuable and economical organic fertilizer- the compost can be adapted country-wide to recycle the urban solid waste as waste management option. Solid urban wastes considerably increase crop yields. In addition, more long-term experimental studies are required to re-validate the use of municipal solid waste compost to enhance the soil’s physical, chemical and biological properties and to raise crop yield.

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For more than a century now, wastewater use in agriculture has been a widespread trend in a number of water-poor developing countries. A number of urban and periurban farmers have been and continue to be supporting their livelihoods. However, with the growing population the volumes of urban wastewater have dramatically increased. The problem is further complicated with increased contamination of wastewater with new chemicals, changing lifestyles of people, and industrial effluents. The environmental and health-related problems of the use of untreated wastewater have become prominent. There is an immediate need to resolve these problems before this untreated wastewater completely pollutes all rivers / natural water sources. Most developed countries have been able to tackle this issue by adequate wastewater treatment and safe disposal with limited environmental and health impacts. Microbial fuel cells (MFCs) are the latest addition to the community of emerging technologies that have the potential to resolve the imminent climate change scenario by pollution alleviation. In addition, they may also act as a solution to the rapidly depleting reserves of fossil fuel by generating direct energy from oxidizable waste, thus remediating it. The upscaling of this technology is a must to offer future benefits. However, the path to MFC upscaling is dissuaded by the inherent overpotential losses that impede maximum achievable voltage attainment. Nevertheless, the increasing knowledge of the technology has largely led to intense work in material science in pursuit of more materials to complement MFC electrodes and membranes to resolve the losses. To boost the electrochemical reactions, electrodes must be modified with the introduction of alloys that are bimetallic, trimetallic, organometallic, etc. Biocompatibility should also be a crucial factor in the selection of materials as microorganisms are the key drivers of this entire electron cycle. As the long-term longevity of this technology is important, therefore the chosen materials should also be durable. Suppose waste materials can be used as a tool for MFC components such as metal laden waste streams as a source of catholyte, junk metals as a source of electrodes/catalyst, etc.. In that case, this technology can be further developed as an eco-friendly solution, it would be a better proposition. AD is an old and well-established process that requires strict anaerobic conditions and depends on a complex microbial cluster’s metabolic activity to biodegrade organic material into biogas. Despite the present information on AD, however, largescale implementation of AD despite full control of all the parameters is not feasible. In general, hydrolysis is considered to be the rate-limiting step. Various disintegration methods have been explored to enhance the rate of hydrolysis and improve process efficiency. Among the reported techniques, mechanical, thermal, and chemical pretreatments have been studied deeply and applied commercially, whereas the literature on biological pre-treatments is scarce. Although biogas’ processing is a commercially available technique, its use worldwide is still limited due to the stringent purification criteria prior to its use. This review found that further effort is required to address the information gap between the various improvement techniques and their operations on a large scale. In India, several financial and nonfinancial barriers exist resulting in the low reach of biogas technology and barriers vary strongly between biogas system in urban and rural areas due to differences in technology maturity, feedstock availability and quality, supply chain, awareness level and policy support.

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3.3 Waste and Sustainability The high durability of plastic creates a great risk to the environmental system i.e. landfill, emission of toxic gases like CO, CO2 , SO2 , NOx , global warming, acidic rain, depletion of the ozone layer, leaching of chemicals and pollution. Dangers associated with healthcare waste and its management have increased dedication in various processes, local and international incentives, and meetings around the world. Nevertheless, due to significant disease burdens associated with unsafe procedures, exposure to infectious agents and hazardous chemicals, the need for careful management of healthcare waste has slowly gained attention. Only a minimal law exists on decomposable plastics in soil at world level. Conditions, constraints, and testing procedures aimed at classification, cataloging, and authentication of cultivated plastic leftover torrents through probable biodegradation in soil rendering to present global values are analysed, whereas appropriate disagreements are acknowledged. While India is a small gold producer, it has huge domestic demand and a strong gold consumption market. Demand from the ornamental and electronic sectors is further growing. The huge gold demand makes India the largest importer country of gold in the world. India is not enriched with a large gold deposit and with the closure of Kolar gold mines (with effect from 1.3.2001, due to deep mining and depletion of gold reserves, India is a minor producer of gold. Though there is an increase in primary gold production during 2016–2017, i.e. increased by 3% compared to the previous year. Currently, there are only two major working mines with few small scale gold producing mine in India. The present and near-future production of gold will not be able to meet the ever-increasing demand, and hence, alternate source for gold is required to reduce the gap between production and demand. Given the current scenario of the enormous gap between gold production and demand, gold phytomining is an economically viable alternative and environmentally friendly technology for meeting India’s gold requirement.

4 Recommendations Throughout the course of this book project, the editorial teams noticed some areas that could be discussed to further develop. Based on the findings and conclusions of the authors, this section offers a collection of recommendations which provide suggestions for future researchers to exceed this book’s reach. The following recommendations are mainly obtained from the chapters presented in this volume: • For the treatment of mixed solid waste advanced treatment systems should be considered. For the proper implementation of these technologies on a larger scale, a cost-effective and end-use analysis should be included for each solid waste treatment process. Considering the versatile/heterogeneous composition of solid waste, selection of proper treatment technologies should be performed to eliminate the segregation process of solid waste (such as plastics, food waste, tyres, etc.).

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• Steel Slag (SS) waste can be a viable and sustainable alternative as Recycled Aggregates (RA) for the concrete industry and can easily merge the gap of Natural Aggregates (NA). The study suggests and recommends the use of SS waste as RA for low-grade concrete (M-20) up to a replacement level of 30–50%. Furthermore, the present work gives information to decision-makers and various stakeholders of Indian and International steel sector to emphasis on use of SS as an RA for implementing sustainability in steel sector. • The various environmental effects of heavy metals and their treatment methods are listed here. Nonetheless, some problems remain unresolved and further investigation conditions are mentioned as follows: The adsorbent’s surface must be activated beforehand by a chemical or physical process to increase the adsorption capacity. Analysis of reports from results of various studies should be carried out unmistakably among different mechanisms available for the removal of heavy metals. The ion exchange resins should be frequently regenerated. However, regeneration causes environmental pollution. Steps should be taken to minimize the secondary pollution in the environment. • The chemical products should be properly stored and disposed of. Waste has to be treated with physicochemical methods such as electro-coagulation accompanied by residual waste biodegradation. Further, there should be proper environmental management facility adopted at an industrial scale for the treatment of such type of wastes. • While water runoff and soil loss play an important role in determining nutrient loss (N&P) in riparian ecosystems, physical, biological and hydrological factors (precipitation, rainfall and evapotranspiration) can be used to determine nutrient concentration. It may be suggested that the protection of riparian slopes in respect of soil erosion, water runoff and nutrient loss, native herbs with greater canopy cover and high soil binding capacity may be planted. • The existing composting activities for industrial waste in India should be strengthened and well organized on the basis of the various national schemes currently being formulated. Some guidelines for further refinement noted below: There is an immediate need for knowledge among the common people of the value of source segregation at the point of production as biodegradable, inert, and recyclable material for proper urban waste management. In India, more composting plants should be constructed for the smooth operation of the plants in different areas of the cities. Government should help and encourage academic and technical institutions to create infrastructure which facilitates the characterization of waste in their vicinity. It will pave the way for the development of location-specific appropriate solutions for urban waste management. Indian government should take the initiative to develop a policy fiscal intensive and development of quality standards for reuse urban solid waste for sustainable agriculture. Environmental research program should be initiated to sort out the problem like plastic and leachate contamination in ground water, heavy metal pollution in soil, etc. This provides us the appropriate technological solution to remove this barrier for safe use urban waste compost to sustain Indian agriculture.

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• The majority of developed countries have been able to tackle s issue by adequate wastewater treatment and safe disposal with limited environmental and health impacts. Developing countries have consistently sought and failed to implement similar west world water treatment technologies. There are both social and economic reasons for this failure. It is very important to understand the social and economic context of a society/community/city before the technology is implemented. The different social-economic aspects of being considered are— perceptions of people regarding water, education levels, awareness towards the environment and the willingness and ability to pay to protect their environment. In addition to this, political will and institutional support are essential to make wastewater a safe asset for people in developing countries. With climate change problems, growing urbanization and increased water demand from competing industries, wastewater recycling is becoming a significant strategy for complementing existing water supplies for both developing and developed countries, and there are lessons, insights, data and technologies that can be exchanged for mutual benefit. • Following guidelines, the use of food waste for domestic fuel and electricity generation is proposed. To build a large-scale biogas digester, i.e. in a joint family, a school where students, college canteen, restaurant and hotels are served mid-day meal. There is need of dissemination of this economical biogas digester. It will generate employment to urban and rural people by providing training to the people. It will reduce the emission of greenhouse gases and eutrophication of the aquatic ecosystems. The digester will provide organic manure which can be utilized for the cultivation of organic crops, is of great demand in recent years. The biogas digester can be made more economical by carrying out more research and development. Policymakers must include biogas output from food waste for sustainable utility in the waste management guidelines for its implementation. The government will take the initiative for its mass propagations and make its installation compulsory where the government serves midday meals in the schools. • MFC has far more potential than to serve as an alternate source of energy, which needs to be explored in future times. The added benefit of waste treatment in addition to power generation has found multiple buyers and believers of this technology. In addition, eco-friendly methods such as the green synthesis protocol should be implemented as much as possible for the materials needed for manufacture. We should expect a major increase in MFC-based work in the following years, to take this technology a step further towards commercialization. • For the further development of AD, it is suggested that attention be provided to optimizing the different factors or combining two or more factors influencing the levels of the different steps of AD and thus the efficiency to promote the success of the digestive process, more studies related to the strengthening of microbial metabolism and stimulating the degradation of organic matter should be done. Government should pay attention on framing new policies and regulations to promote biogas usages and active participation of independent bodies to increase the amount of upgraded biogas.

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• Waste plastic is very harmful for humans as well as the environment. Plastics in the environment, whether as macro-plastic wreckage or as micro-plastics, have extensively been recognized as a universal problem. So, management of waste plastic i.e. healthcare waste, soil, household plastic, marine plastic is very important. • In the current scenario of widening the gold output gap with its huge demand in India, phytomining may be a viable choice to bridge this gap to some degree in order to reduce our country’s gold imports. • Recommendations from the report and general understanding of soil erosion and the choice of soil conservation measures are as follows: The multi-criteria decision support like analytical hierarchal process can be used conveniently in decision support. The selection of criteria for identifying stressed areas is region-specific and knowledge and geological setup, soils, slope, geomorphology, and land use should be used to select appropriate environmental hazard parameters. The remote sensing data in GIS can be used conveniently for the determination of the spatial distribution of different parameres and the identification of most appropriate soil conservation measures. Climate change may further aggravate the soil erosion and it is necessary to consider the impact of climate variability and extreme events on soil erosion processes. Identifying suitable areas and site-specific soil conservation measures is a difficult task. The multi-criteria decision support (MCDS) and weighted overlay technique-based design of soil conservation measures may be useful to convince the decision-makers and managers for soil conservation measures for getting appropriate results to reduce soil degradation.

References 1. Kumar, S., Smith, S. R., Fowler, G., Velis, C., Kumar, S. J., Arya, S., Kumar, R. R., & Cheeseman, C. (2017). Challenges and opportunities associated with waste management in India. Royal Society Open Science, 4, 160764. https://doi.org/10.1098/rsos.160764. 2. Serge Kubanza, N., & Simatele, M. D. (2019). Sustainable solid waste management in developing countries: a study of institutional strengthening for solid waste management in Johannesburg, South Africa. Journal of Environmental Planning and Management. https://doi.org/ 10.1080/09640568.2019.1576510. 3. Fernández-González, J. M., Grindlay, A. L., Serrano-Bernardo, F., Rodríguez-Rojas, M. I., & Zamorano, M. (2017). Economic and environmental review of waste-to-energy systems for municipal solid waste management in medium and small municipalities. Waste Management, 67, 360–374. https://doi.org/10.1016/j.wasman.2017.05.003 4. Lombardi, L., Carnevale, E., & Corti, A. (2015). A review of technologies and performances of thermal treatment systems for energy recovery from waste. Waste Management, 37, 26–44. https://doi.org/10.1016/j.wasman.2014.11.010 5. Harichandan, B., Venugopal, R., & Dash, A. K. (2017). Implementation of mineral processing techniques to minimize waste generated in steel plant. Geominetech: The Indian Mineral Industry Journal, 04(02), 12–16 http://geominetech.org/docs/2017/ebooks/ism1.pdf 6. IBM, Indian Bureau of Mines. (2017). Slag-Iron and Steel. Indian Minerals Yearbook, Part- II: Metals & Alloys, 55th Edition, 2016. Ministry of mines, Government of India. http://ibm.nic.in/writereaddata/files/08242017152436IMYB2016%20Slag% 20Iron%20and%20STeel_Advance%20release.pdf

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A. M. Negm et al.

7. Jin, S., et al. (2017). Effect of the magnetic core size of amino-functionalized Fe3O4mesoporous SiO2 core-shell nanoparticles on the removal of heavy metal ions. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 531, 133–140. 8. Das, S., et al. (2014). 2—heavy metals and hydrocarbons: adverse effects and mechanism of toxicity. In S. Das (Ed.), Microbial biodegradation and bioremediation (pp. 23–54). Elsevier. 9. Patneedi, C. B., & Prasadu, K. D. (2015). Impact of pharmaceutical wastes on human life and environment. Rasayan Journal of Chemistry, 8(1), 67–70. 10. Duguma, E., Faye, T., Kiros, A., & Balew, A. (2018). Municipal solid waste generation and disposal in Robe town, Ethiopia. Journal of the Air and Waste Management Association. https:// doi.org/10.1080/10962247.2018.1467351 11. Smith, J., Nayak, D. R., Albanito, F., Balana, B. B., Black, H. I. J., Boke, S., & Phimister, E. C. (2019). Treatment of organic resources before soil incorporation in semi-arid regions improves resilience to El Niño, and increases crop production and economic returns. Environmental Research Letters, 14(8). 12. Harish Damodaran (2018). Urban waste, no longer trash for fertilizers firms. Agri Business August 22, 2018. 13. Zohoori, M., & Ghani, A. (2017). Municipal Solid Waste Management Challenges and Problems for Cities in Low-Income and Developing Countries. International Journal of Science and Engineering Applications, 6, 2–8. 14. Hagos, K., Zong, J., Li, D., Liu, C., & Lu, X. (2017). Anaerobic co-digestion process for biogas production: Progress, challenges and perspectives. Renewable Sustainable Energy Review, 76, 1485–1496. 15. EPD. (Environmental Protection Department). (2017). Monitoring of Solid Waste in Hong Kong- Waste Statistics for 2016. 1–35. https://www.wastereduction. gov.hk/sites/default/files/msw2016.pdf 16. Dhar, H., Kumar, P., Kumar, S., Mukherjee, S., & Vaidya, A. N. (2016). Effect of organic loading rate during anaerobic digestion of municipal solid waste. Bioresource Technology, 217, 56–61. 17. Central Statistics Office. (2016). Energy statistics 2016. Ministry of Statistics and Programme Implementation Government of India. 18. Li, X., Peng, Y., He, Y., Wang, S., Guo, S., & Li, L. (2017). Anaerobic stabilization of waste activated sludge at different temperatures and solid retention times: Evaluation by sludge reduction, soluble chemical oxygen demand release and dehydration capability. Bioresource Technology, 227, 398–403. 19. Gurjar, B. R., & Tyagi, V. K. (2017). Sludge management. CRC Press, Taylor & Francis Group. 20. Liao, X., Li, H., Zhang, Y., Liu, C., & Chen, Q. (2016). Accelerated high-solids anaerobic digestion of sewage sludge using low-temperature thermal pretreatment. International Biodeterioration and Biodegradation, 106, 141–149. 21. Li, H., Zhang, Y., Liu, C., Chen, Q., & Si, D. (2016). Evolution of microbial community along with increasing solid concentration during high-solids anaerobic digestion of sewage sludge. Bioresource Technology, 216, 87–94. 22. Geyer, R., Jambeck, J. R., & Law, K. L. (2017). Production, use, and fate of all plastics ever made. Science Advances, 3, e1700782. 23. Adamcová, D., Zloch, J., Brtnický, M., & Vaverková, M. D. (2019). Biodegradation/disintegration of selected range of polymers: impact on the compost quality. Journal of Polymers and the Environment, 27, 892–899. 24. Khatun, M., & Singh, S. (2017). Petrographic and ore microscopic study of carbonaceous host rocks and associated gold mineralization within Dalma volcano-sedimentary basin, North Singhbhum Mobile Belt, Eastern Indian Craton. Journal of Geoscience Research, 1, 35–41.