Agro-Waste Management and Valorization
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Persons
Richa Tiwari is currently pursuing Ph.D. Laxminarayan Innovation Technological University. Her research interest includes Biofuels, environmental impact assessment, waste oils, sustainable development and recycling technologies.
Pramod Belkhode has been serving as the Associate Professor of Mechanical Engineering in the Department of General Engineering at Laxminarayan Innovation Technological University, Nagpur from 2009. His research areas include automation, the theory of experimentation, ergonomics, man machine system and agricultural mechanization.
Samuel Lalthazuala Rokhum is an Associate Professor at the Department of Chemistry, National Institute of Technology Silchar, Assam, India. His research interests include organic chemistry, renewable energy, material science, and heterogeneous catalysis. He has published more than 140 research papers and 21 book chapters.
Content
1.1 Introduction
1.2 Classification of Waste
1.3 Current Status in Waste Management
1.4 Problems Encountered in Waste Handling
1.5 Economic Competitiveness
1.6 Sustainable Challenges
1.7 Carbon sequestration for Green and Sustainable environment
1.8 IoT Services
1.9 Smart city infrastructure
1.10 Conclusion and Discussion
2 A Perspective on the Emergence and Need for Alternate Fuels
2.1 Introduction
2.2 Challenges Associated with Conventional Fuels
2.3 Alternative Fuels
2.4 Types of Alternative Fuels
2.5 Applications of Alternative Fuels
2.6 Environmental Impact and Economic Feasibility
2.7 Future Aspects of Alternative Fuels
2.8 Conclusion
3 The Role of Waste in the Circular Economy, Policies and Legislation
3.1 Introduction
3.2 Crucial Reasons for Implementing a Circular Economy
3.3 Principal of the Circular Economy
3.4 Role of Agro Waste in Circular Economy - Examples
3.5 Circular Economy Challenges
3.6 Agro Waste
3.7 Agro Waste Management: Current Practices
3.8 Challenges in Implementing the Circular Economy for Agro Waste
3.9 Conclusion
4 Waste Management
4.1 Introduction
4.2 Assessment of RDF and SRF
4.3 MSW & RDF/SRF Legislation
4.4 Type of Solid Waste
4.5 Pelletization & Incineration
4.6 Case Study: Energy Recovery Potential
4.7 Liquid Waste Management
4.8 Physico-Chemical Treatment
4.9 Physical or Mechanical Treatment
4.10 Biological Treatment
4.11 E-waste
4.12 Environmental and Health Impacts of Waste Mismanagement
4.13 Disposal Methods of Waste Management
4.14 Environmental Impacts and Considerations
4.15 Sustainable Waste Management
4.16 Biological Conversion Techniques
4.17 Thermochemical Conversion Techniques
4.18 Techno-Economic Analysis (TEA) and Life Cycle Assessment (LCA): Evaluating Sustainability
4.19 Emerging Technologies and Future Trends: Shaping the Future of Agrowaste Management
4.20 Conclusion
5 Waste Biorefinery
5.1 Introduction
5.2 Waste feedstock for biorefinery
5.3 Kinetic analysis of biomass
5.4 Conversion Processes
5.5 Water based biorefinery
5.6 The economic aspects of waste-to-energy biorefineries
5.7 Conclusion
6 Algal Biorefinery
6.1 Introduction
6.2 Algal Biomass Cultivation
6.3 Algal Biomass Processing
6.4 Biofuel Production from Algal Biomass
6.5 Bioproducts and Bio-compounds from Algae
6.6 Integrated Algal Biorefinery Approach
6.7 Genetic Engineering and Algal Strain Improvement
6.8 Environmental Sustainability and Life Cycle Assessment in Algal Biorefining
6.9 Challenges and Future Perspectives
6.10 Conclusion
7 Waste to Bio-Additive
7.1 Introduction
7.2 Types of waste utilized for bio-additive production
7.3 Waste to bio-additive conversion technologies
7.4 Application of Bio-additives
7.5 Life Cycle assessment (LCA) of WtBA technologies
7.6 Challenges and Limitations
7.7 Case studies and success stories
7.8 Conclusion and Recommendations
8 Waste to Compost
8.1 Introduction
8.2 Defining and Categorizing Agrowaste for Composting
8.3 The Science of Composting: Biochemical Processes and Microbial Ecology
8.4 Composting Methodologies for Agrowaste: From Traditional to Advanced Techniques
8.5 Advanced Composting Methodologies
8.6 Factors Influencing Composting Efficiency and Compost Quality
8.7 Conclusion
9 Glycerol: From Abundant Byproduct to Valuable Bio-oil
9.1 Introduction
9.2 Production of Glycerol in Biodiesel Production:
9.3 Conversion Technologies of Glycerol to Bio-oil
9.4 Bio-oil Properties and Applications
9.5 Catalytic Processes for Glycerol Conversion to Bio-oil
9.6 Chemistry of Glycerol Conversion to Bio-oil
9.7 Reactor Design and Process Optimization for Glycerol Conversion to Bio-oil
9.8 Challenges and Limitations
9.9 Commercial Glycerol-to-Bio-oil Plants
9.10 Conclusion
10 Production of Biochar
10.1 Introduction
10.2 Agrowaste Feedstocks for Biochar Production
10.3 Pyrolysis: Thermal Decomposition
Chapter 1
Waste-to-value Opportunity and Challenges
1.1 Introduction
Rapid economic growth and urbanization worldwide have resulted in a substantial increase in resource consumption and waste generation. Disposing of this growing volume of solid waste, particularly in landfills, is often neither economically feasible nor sustainable in urban environments. Energy recovery from waste, resource recovery, and waste volume reduction represent attractive and viable alternatives for waste management. Extracting energy from waste minimizes the need for energy produced from finite resources. Therefore, there is an urgent need to develop sustainable strategies for waste management. This study explores the latest advancements in sustainable waste-to-energy (WtE) technologies, resource recovery methods, and low-carbon biotechnologies and bioenergy options. Recent research highlights the growing importance of the circular economy as a sustainable waste management approach [1, 2]. WtE alternatives are crucial in the waste management sector. This chapter presents an innovative approach focused on addressing the challenges of managing organic waste by integrating WtE technologies. Globally, there is increasing emphasis on sustainable waste management practices, as utilizing organic waste for WtE purposes is a viable option. Identifying and prioritizing WtE alternatives is key, given the large quantities of waste in the management system. The goal is to reduce the environmental and logistical impacts of organic waste disposal, contributing to a more efficient and sustainable waste management system aimed at minimizing environmental effects and producing renewable energy. Ludlow et al. [3] emphasize that achieving net-zero greenhouse gas (GHG) emissions by 2050 fundamentally requires a shift in waste management practices. Organic waste disposal frequently presents significant challenges, including insufficient collection infrastructure, limited public awareness, and operating difficulties, particularly in urban areas. Daily per capita waste generation varies considerably globally, ranging from 0.11 to 4.54 kg [4].
Managing waste involves complexity and costs, which differ depending on local resource allocation and population density. However, as waste volume and disposal costs rise, developing countries face significant challenges in managing waste effectively [5]. Despite these challenges, alternative waste management options, such as anaerobic digestion (AD), pyrolysis, and gasification, are gaining traction. Implementing effective waste management practices and technologies is critical for mitigating negative environmental and health impacts [6]. Developing nations urgently need to adopt sustainable waste management practices.
1.1.1 Waste-to-energy
WtE technologies are commonly employed for sustainable waste management, facilitating simultaneous energy generation and effective disposal [7]. Among WtE methods, thermal conversion is the most widely adopted approach for large-scale waste-processing. Incineration, a thermal technology, is still under development; while pyrolysis remains experimental, it is not yet commercially viable for managing municipal solid waste (MSW) globally. Biological conversion methods like AD are also used, particularly for bio-methanization. AD is frequently utilized for processing organic-rich biodegradable waste like manure and sewage sludge [8]. Using landfills for waste disposal is less favored due to drawbacks such as unpleasant odors, GHG emissions from methane (CH4), leachate production, and associated health risks. Evidence suggests that WtE technologies implemented in Latin American and Caribbean (LAC) countries offer long-term advantages, including economic development, environmental benefits, and improved human well-being [9]. Existing literature provides a detailed look at the scale of waste challenges in developing nations and explores potential methods to promote sustainable waste management practices in the future.
This chapter helps fill knowledge gaps by analyzing treatment methods used in developing countries and their potential to support continuous sustainability by aligning with renewable energy sources such as hydroelectricity, which are environmentally friendly and non-emission-generating. For example, South Africa's electricity mix in 2021 heavily relied on coal-fired plants (84%), resulting in substantial CO2 emissions of 396 g CO2/kWh. Energy consumption also surged sharply in New Zealand (66 kg CO2/kWh, primarily powered by geothermics [57%], hydro [17%], and thermal sources ([9%]) [10, 11]. The rapid urbanization in many developing countries intensifies waste management challenges.
Nonetheless, these challenges also present significant opportunities. Treating waste as a valuable resource rather than a problem allows different nations to adopt sustainable waste management techniques and achieve future development goals. Studies conducted in Korea demonstrate how WtE operations reduced GHG emissions by 16,061 tCO2eq annually; this reduction is projected to increase further to 26,477 tCO2eq per year by 2021 [12]. The environmental advantages of WtE technologies (like incineration, pyrolysis, gasification, and incineration) vary depending on the specific method used [13]. The purpose of this chapter is to provide a systematic evaluation and highlight the benefits and challenges of WtE technology, especially in developing countries. This includes assessing the characteristics and volume of waste produced, current treatment methods, the opportunities and obstacles within the waste management sector, and the feasibility of implementing or expanding WtE solutions domestically.
1.1.2 Environmental Benefits
Figure 1.1 illustrates that incineration notably influences the global warming potential (GWP), contributing between 975,554 and 830,750 tCO2-eq/year due to the large quantity of processed waste. In thermal technologies, emissions are a primary contributor to the GWP [14]. The environmental impact of incineration is largely dictated by its energy conversion efficiency; higher efficiency leads to lower emission rates. For instance, an incineration plant operating at 25% efficiency emits roughly 1,007 kg CO2-eq per MWh of combustion, while increasing efficiency by just 5% (to 30%) reduces emissions by approximately 17% due to lower GHG emissions [15]. The significant emission reductions from incineration can be attributed to the characteristics of the burned materials. Plastic waste, comprising over 20% of facility input, has the most notable impact on GWP due to its chemical properties and low moisture content, resulting in greater emission contributions [16]. Moreover, the common practice of disposing of MSW without source separation leads to high moisture levels [17]. Achieving greater environmental and economic benefits from WtE technologies requires continuous improvements.
Figure 1.1 GHG emissions and emission saving from WtE technologies (tCO2-eq/year). Adapted from [16].
1.1.3 Energy Generation Potential
Uncollected CH4 (25%) from landfill gas (LFG) is a major factor contributing to GWP, amounting to 417,533 tCO2-eq/year of GHG emissions [18]. In contrast, AD methods produce the lowest emissions, achieving 99% efficiency in capturing CH4, leaving only 5% to be released into the atmosphere. The environmental performance of WtE technologies compared to coal-based electricity generation was also examined [19]. Research indicates that LFG recovery results in the highest net GWP, estimated between 137,439 and 323,604 tCO2-eq annually. Incineration shows a lower GWP, ranging from 219,121 to 84,803 tCO2-eq/year. Incineration with energy recovery surpasses simple incineration in reducing emissions. Energy generation from WtE can offset some of the benefits gained from electricity production but significantly counteracts global warming effects. AD technology has substantially reduced impact on GWP, resulting in an avoidance of 95,321-195,395 tCO2-eq/year of GHGs. From an environmental standpoint, AD technology is arguably the most suitable option due to its lower emissions.
1.1.4 Economic Potential
The global waste recycling services market is projected to reach US$99.2 billion by 2032, with an average annual growth rate of 5.1% from 2023 to 2032 [20]. In 2022, the Asia-Pacific region's waste recycling services market constituted over 80% of the total market share. The US Environmental Protection Agency (EPA) reports that the recycling industry employs 534,000 people and contributes US$13.2 billion in wages and benefits [15]. An analysis indicates that in 2020, only 9% of electronic waste (e-waste)was properly collected and recycled [21]. According to the EPA, the United States generated 292.4 million tons of MSW in 2018, of which 69 million tons were recycled [22]. The increasing adoption of advanced WtE technology offers substantial potential for adding value to waste and generating energy [23]. The precise potential varies based on factors such as the type and volume of available waste, technological readiness, environmental considerations, and government policies. Figure 1.2 illustrates potential applications of waste recycling and processing technologies that significantly influence the waste recycling services market value.
Figure 1.2 Potential of waste-to-energy (WtE) technology. Adapted from [24].
WtE presents considerable potential, but its viability is dependent on various...
