Emerging Energy Alternatives for Sustainable Environment 9780429608810, 0429608810

Table of contents :
Content: Cover --
Half Title --
Title Page --
Copyright Page --
Table of Contents --
Preface --
1: Biogas Potential in India: Production, Policies, Problems, and Future Prospects --
1.1 Introduction --
1.2 Production of Biogas --
1.3 Sources/Materials for Biogas Production --
1.4 Roles of Microbes in Production of Biogas --
1.5 Issues and Concerns for the Biogas Production Process --
1.6 Augmentation/Upgradation of Biogas Process --
1.7 Types of Biogas Reactors --
1.8 Policies Related to Biogas Production in India --
1.9 Benefits of Biogas Energy Production-Potential in India --
1.10 Problems and Issues Encountered --
1.11 Future Prospects for Biogas in India --
1.12 Conclusion --
References --
2: Membrane-less Microbial Fuel Cell: A Low-cost Sustainable Approach for Clean Energy and Environment --
2.1 Introduction --
2.2 Basic Requirements for Membrane-less Microbial Fuel Cell --
2.3 Classification of Membrane-less Microbial Fuel Cell --
2.4 Conclusion --
Acknowledgements --
References --
3: Hydrogen Energy: Present and Future --
3.1 Introduction --
3.2 Hydrogen Production --
3.3 Storage Technologies for Hydrogen --
3.4 Hydrogen Energy and Environment --
3.5 Hydrogen and Other Alternative Secondary Energies --
3.6 Hydrogen Safety --
3.7 Future Prospects of Hydrogen --
References --
4: Emerging Energy Alternatives for Sustainable Development in Malaysia --
4.1 Introduction --
4.2 Renewable Resources in Malaysia --
4.3 Conclusion --
References --
5: Role and Initiatives of Indian Government Policies for Growth of Wind Energy Sector --
5.1 Introduction --
5.2 India's Wind Energy Potential and Installation --
5.3 Indian Government Policies for Wind Energy Sector --
5.4 State Government Policies for Wind Energy Sector --
5.5 Conclusion --
References --
6: Improved Technology for Non-edible Seed Oils: Sources for Alternate Fuels --
6.1 Introduction. 6.2 Materials and Methods --
6.3 Results and Discussion --
6.4 Conclusion --
References --
7: Adsorption and Photodegradation of Sulfamethoxazole in a Three-phase Fluidized Bed Reactor --
7.1 Introduction --
7.2 Methodology --
7.3 Results and Discussion --
7.4 Conclusion --
Acknowledgements --
References --
8: Application of Cellulose Nitrate Membrane for Pervaporative Separation of Organics from Water --
8.1 Introduction --
8.2 Experimental Set-up --
8.3 Results and Discussion --
8.4 Conclusion --
Acknowledgements --
References --
9: Green Chemistry: Mitigatory Measure for Environmental Pollution --
9.1 Introduction --
9.2 Green Chemistry Concept --
9.3 History --
9.4 A Timeline of Green Chemistry Highlights --
9.5 Scope --
9.6 Principles --
9.7 Role of Green Chemistry in Prevention and Control of Pollution --
9.8 Environmental Sustainability --
9.9 Conclusion --
References --
Websites --
10: Building Energy Simulation for Improved Thermal Performance: A CFD Approach --
10.1 Introduction --
10.2 Thermal Mass and Building Design --
10.3 Building Energy Analysis --
10.4 Necessity for Building Simulation --
10.5 Application of Building Simulation and Systems Approach --
10.6 Software --
10.7 Applications of CFD for Building Design --
10.8 Conclusion --
References --
11: Cyanobacterial Biomass --
A Tool for Sustainable Management of Environment --
11.1 Introduction --
11.2 Approaches to Biofertilizer Application --
11.3 Cyanobacteria: A Biofertilizer --
11.4 Nitrogen Fixation --
11.5 Cyanobacteria: A Nutrient Source --
11.6 Cyanobacteria: A Pesticide Tolerant --
11.7 Cyanobacteria: A Salinity Tolerant --
11.8 Cyanobacteria: A Bioremediation Tool --
11.9 Cyanobacteria: A CO2 Sequestration Agent --
11.10 Nutrient Management System --
References --
12: Low-cost Production of Algal Biofuel from Wastewater and Technological Limitations --
12.1 Introduction. 12.2 Classification of Algae --
12.3 Factors Affecting Growth of Microalgae --
12.4 Sink for Carbon dioxide --
12.5 Wastewater as a Resource for Algal Growth --
12.6 Microalgae Cultivation Methods --
12.7 Harvesting Technologies for Algal Biomass --
12.8 Lipid Synthesis in Microalgae --
12.9 Conversion Technologies for Algal Biofuel --
12.10 Limitations with Biomass/Biofuel Production --
12.11 Conclusion --
References --
13: Physical and Chemical Exergy Analysis and Assessment of Biogas as an Energy Source in Hybrid Cooling Machine --
13.1 Introduction --
13.2 System Description and Working Principle --
13.3 Thermal Analysis of Biogas Boiler --
13.5 Thermodynamic Analysis --
13.6 Results and Discussion --
13.7 Conclusion --
References --
14: Lignocellulosic Biomass to Bioenergy Production: Process and Techniques for Biomass Assessment --
14.1 Introduction --
14.2 Process of Biomass Deconstruction --
14.3 Techniques for Assessment of Biomass Breakdown --
14.4 Current Challenges and Future Prospects --
References --
15: Municipal Solid Waste Management in India: Present Status and Energy Conversion Opportunities --
15.1 Introduction --
15.2 Overview of Municipal Solid Waste Management in India --
15.3 Opportunities for Energy Conversion --
15.4 Challenges --
15.5 The Way Forward --
15.6 Conclusion --
Acknowledgements --
References --
16: Organic Superfluous Waste as a Contemporary Source of Clean Energy --
16.1 Introduction --
16.2 Current Status of Energy --
16.3 Bioenergy --
16.4 Organic WasW te --
16.5 Technology for Energy --
16.6 Microbial Fuel Cell --
16.7 MFC Components --
16.8 Bio-battery --
16.9 Remote Power Source --
16.10 Effective for Sea Water --
16.11 Conclusion --
Acknowledgements --
References --
17: Vermicomposting: A Potential Tool for Sustainable Management of Solid Waste --
17.1 Introduction. 17.2 Classification and Composition of Solid Waste --
17.3 Current Strategies used for Solid Waste Management in India --
17.4 Earthworms --
17.5 Vermicomposting Process --
17.6 Vermicompost and Earthworm Harvesting --
17.7 Composition of Vermicompost --
17.8 Advantages and Disadvantages of Vermicompost --
17.9 Applications of Vermicomposting --
17.10 Conclusion --
References --
18: Biogas Potential from Sewage Treatment Plant and Palm Oil Mill Effluent for Electricity Generation in Malaysia --
18.1 Introduction --
18.2 Renewable Energy Status in Malaysia and Malaysian Renewable Energy Target --
18.3 Feed-in Tariff in Malaysia --
18.4 Malaysian Palm Oil Industry --
18.5 Biogas Potential in Palm Oil Mills --
18.6 Malaysian Sewerage Treatment --
18.7 Typical Sewage Treatment Plant with Anaerobic digester Scenario in Malaysia --
18.8 Biogas Potential at STP --
18.9 Co-digestion of Pome with SS --
18.10 Impact of Biogas Recovery on Sustainability --
18.11 Conclusion --
Acknowledgements --
References --
19: Passive Energy in Residential Buildings --
19.1 Introduction --
19.2 Passive Solar Cooling --
19.3 Methodology --
19.4 Estimation of Energy Cost --
19.5 Conclusion --
References --
20: Solar Photocatalytic Treatments of Wastewater and Factors Affecting Mechanism: A Feasible Low-cost Approach --
20.1 Introduction --
20.2 Solar Spectrum --
20.3 Design of Solar Photocatalytic Reactors --
20.4 Photocatalytic (Solar) Treatment of Pollutant --
20.5 Factors Affecting Solar Photocatalysis --
20.6 Recommended Analytical Methods --
20.7 Economical Assessment --
20.8 Conclusion --
References --
21: Advancement in Phase Change Materials for Solar Thermal Energy Storage --
21.1 Introduction --
21.2 Phase Change Materials --
21.3 Application of PCMS --
21.4 Conclusion --
References. 22: Earth to Air Heat Exchanger Systems for Small Houses and Industrial Buildings in Changing Indian Climatic Conditions --
22.1 Introduction --
22.2 Changing Indian Climatic Conditions --
22.3 Indian Climate and EAHE Systems --
22.4 Demand for Energy in India --
22.5 Advantages of EAHE System --
22.6 Design of EAHE Systems --
22.7 Components of EAHE System --
22.8 Performance of EAHE System --
22.9 Conclusion --
References --
23: Development in Metal Oxide Nanomaterial-based Solar Cells --
23.1 Introduction --
23.2 History of Solar Cell --
23.3 Metal Oxide Nanomaterials --
23.4 Three Generations of Development --
23.5 Nanomaterial-based Solar Cell Research --
23.6 Thin Film Solar Cells --
23.7 Applications and Implementations --
23.8 Polymer Solar Cells --
23.9 PV Industry Goal: Reduce Cost of Energy --
23.10 Conclusion --
References --
Index --
About the Editors.

Citation preview

EMERGING ENERGY ALTERNATIVES FOR SUSTAINABLE ENVIRONMENT

EMERGING ENERGY ALTERNATIVES FOR SUSTAINABLE ENVIRONMENT EDITORS D P Singh • Richa Kothari • V V Tyagi

The Energy and Resources Institute

CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2019 by D P Singh, Richa Kothari, V V Tyagi and The Energy and Resources Institute CRC Press is an imprint of the Taylor & Francis Group, an informa business No claim to original U.S. Government works International Standard Book Number-13: 978-0-367-17889-5 (Hardback) Print edition not for sale in South Asia (India, Sri Lanka, Nepal, Bangladesh, Pakistan or Bhutan) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a notfor-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Library of Congress Cataloging in Publication Data A catalog record has been requested Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com

Preface

Sustainability of environment is an emerging global issue at present. Unsustainable or deteriorating environment is a matter of concern as it has threatened the survival of living creatures. Recently, climate change has been matter of great concern at a global platform owing to imbalances in natural environment. Increasing population has increased the demand for energy, which has ultimately put pressure on natural resources and caused a paradigm shift from resource generation to exploitation. Fossil fuels are limited reserves of energy on the earth which are now declining at an accelerated rate, and soon it will be a resource of the past. The lion’s share of energy generation depends on fossil fuels, and hence we are moving fast towards an arena of energy crisis. Rapid industrialization and huge consumption of fossil fuels have adversely affected our environment and become a major contributor to global warming. The paradigm shift towards renewable energy technology is the major innovation of the decades. The thrust on renewable energy-based power generation will not only be environmentally friendly, but it will also ensure the energy security. In the past years, various dimensions of renewable energy have been developed, such as biomass, solar, wind, hydro, and geothermal energy. Although there is immense potential for energy generation from renewable energy, various issues related to these sources of energy still need to be resolved. Emerging green energy technologies are the healing technology for environment that covers a wide spectrum of materials and methods, leading energy generation to non-toxic, clean, and green products. Government of India is also making every effort to achieve the clean development mission through energy generation by solar and other green energy sources. Green chemistry and engineering are the most advanced fields of technology, which have the potential to boost the nation’s economy in coming years. Emerging Energy Alternatives for Sustainable Environment aims to address the role of sustainable technologies in energy generation options for clean environment. It covers a wide spectrum of energy generation approaches, with an emphasis on five key topics: (i) renewable energy sources and recent advances, (ii) emerging green technologies for sustainable development, (iii) assessment of biomass for sustainable bioenergy production, (iv) solid waste management and its potential for energy generation, and (v) solar energy applications, storage system, and heat transfer. This book provides essential and comprehensive knowledge of

vi

Preface

green energy technologies with different aspects for engineers, technocrats and researchers working in the industry, universities, and research institutions. The book is also very useful for senior undergraduate and graduate students of science and engineering who are keen to know about the development of renewable energy products and their corresponding processes. We acknowledge the help and cooperation by all the contributing authors. We are especially grateful to all the team members, Mr Vinayak Vandan Pathak, Mr Shamshad Ahmed, and Mr Alok Rai, who provided their valuable suggestions and help from time to time. We would especially like to thank Dr Adarsh Kumar Pandey, UMPEDAC, University of Malaya, Malaysia and Mr Ravi Sharma, Department of Mechanical Engineering, Jaypee University of Engineering and Technology, Guna, India, for their helpful suggestions to improve the quality of the book. We are also very thankful to Ms Sushmita Ghosh and all team members of TERI Press for their hard work and timely publication of this book. D. P. Singh Richa Kothari V. V. Tyagi

Contents

Preface

v

1. Biogas Potential in India: Production, Policies, Problems, and Future Prospects 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 1.10 1.11 1.12

1

Introduction Production of Biogas Sources/Materials for Biogas Production Roles of Microbes in Production of Biogas Issues and Concerns for the Biogas Production Process Augmentation/Upgradation of Biogas Process Types of Biogas Reactors Policies Related to Biogas Production in India

1 2 3 5 6 8 13 14

Benefits of Biogas Energy Production—Potential in India Problems and Issues Encountered Future Prospects for Biogas in India Conclusion References

16 19 24 25 26

2. Membrane-less Microbial Fuel Cell: A Low-cost Sustainable Approach for Clean Energy and Environment 2.1 Introduction

35

35

2.2 Basic Requirements for Membrane-less Microbial Fuel Cell 38 2.3 Classification of Membrane-less Microbial Fuel Cell 45 2.4 Conclusion 51 Acknowledgements 51 References 51

3. Hydrogen Energy: Present and Future 3.1 3.2 3.3 3.4 3.5 3.6

Introduction Hydrogen Production Storage Technologies for Hydrogen Hydrogen Energy and Environment Hydrogen and Other Alternative Secondary Energies Hydrogen Safety

57 57 59 66 66 67 69

viii

Contents

3.7 Future Prospects of Hydrogen References

4. Emerging Energy Alternatives for Sustainable Development in Malaysia 4.1 Introduction 4.2 Renewable Resources in Malaysia 4.3 Conclusion References

5. Role and Initiatives of Indian Government Policies for Growth of Wind Energy Sector 5.1 5.2 5.3 5.4

Introduction India’s Wind Energy Potential and Installation Indian Government Policies for Wind Energy Sector State Government Policies for Wind Energy Sector

5.5 Conclusion References

6. Improved Technology for Non-edible Seed Oils: Sources for Alternate Fuels 6.1 6.2 6.3 6.4

Introduction Materials and Methods Results and Discussion Conclusion References

7. Adsorption and Photodegradation of Sulfamethoxazole in a Three-phase Fluidized Bed Reactor 7.1 7.2 7.3 7.4

Introduction Methodology Results and Discussion Conclusion Acknowledgements References

8. Application of Cellulose Nitrate Membrane for Pervaporative Separation of Organics from Water

70 7 71

75 75 76 95 95

99 99 101 103 105 115 116

119 119 122 123 137 138

141

141 142 145 150 151 151

153

8.1 Introduction

153

8.2 Experimental Set-up 8.3 Results and Discussion

154 155

Contents

8.4 Conclusion Acknowledgements References

9. Green Chemistry: Mitigatory Measure for Environmental Pollution

ix 157 158 158

159

9.1 Introduction 9.2 Green Chemistry Concept

159 160

9.3 History 9.4 A Timeline of Green Chemistry Highlights

161 161

9.5 Scope 9.6 Principles 9.7 Role of Green Chemistry in Prevention and Control of Pollution 9.8 Environmental Sustainability 9.9 Conclusion

162 163

References Websites

10. Building Energy Simulation for Improved Thermal Performance: A CFD Approach 10.1 10.2 10.3 10.4 10.5 10.6

168 169

171

Introduction 171 Thermal Mass and Building Design 172 Building Energy Analysis 173 Necessity for Building Simulation 174 Application of Building Simulation and Systems Approach 176 Software 177

10.7 Applications of CFD for Building Design 10.8 Conclusion References

11. Cyanobacterial Biomass – A Tool for Sustainable Management of Environment 11.1 11.2 11.3 11.4

164 166 167

Introduction Approaches to Biofertilizer Application Cyanobacteria: A Biofertilizer Nitrogen Fixation

11.5 Cyanobacteria: A Nutrient Source 11.6 Cyanobacteria: A Pesticide Tolerant

180 188 190

193 193 199 200 200 204 205

x

Contents

11.7 11.8 11.9 11.10

Cyanobacteria: A Salinity Tolerant Cyanobacteria: A Bioremediation Tool Cyanobacteria: A CO2 Sequestration Agent Nutrient Management System References

12. Low-cost Production of Algal Biofuel from Wastewater and Technological Limitations

205 206 206 207 207

211

12.1 Introduction 12.2 Classification of Algae

211 213

12.3 12.4 12.5 12.6 12.7 12.8 12.9

213 215 216 219 222 223 224

Factors Affecting Growth of Microalgae Sink for Carbon dioxide Wastewater as a Resource for Algal Growth Microalgae Cultivation Methods Harvesting Technologies for Algal Biomass Lipid Synthesis in Microalgae Conversion Technologies for Algal Biofuel

12.10 Limitations with Biomass/Biofuel Production 12.11 Conclusion References

13. Physical and Chemical Exergy Analysis and Assessment of Biogas as an Energy Source in Hybrid Cooling Machine

227 230 230

239

13.1 Introduction 13.2 System Description and Working Principle 13.3 Thermal Analysis of Biogas Boiler

239 242 244

13.5 Thermodynamic Analysis 13.6 Results and Discussion 13.7 Conclusion References

245 252 257 258

14. Lignocellulosic Biomass to Bioenergy Production: Process and Techniques for Biomass Assessment

261

14.1 Introduction 14.2 Process of Biomass Deconstruction 14.3 Techniques for Assessment of Biomass Breakdown

261 262 267

14.4 Current Challenges and Future Prospects References

271 271 7

Contents

15. Municipal Solid Waste Management in India: Present Status and Energy Conversion Opportunities 15.1 15.2 15.3 15.4 15.5

277

Introduction 277 Overview of Municipal Solid Waste Management in India 279 Opportunities for Energy Conversion 282 Challenges 294

The Way Forward 15.6 Conclusion Acknowledgements References

16. Organic Superfluous Waste as a Contemporary Source of Clean Energy 16.1 Introduction 16.2 Current Status of Energy 16.3 Bioenergy 16.4 16.5 16.6 16.7 16.8 16.9 16.10 16.11

xi

294 295 296 296

305 305 306 307

Organic Waste W Technology for Energy Microbial Fuel Cell MFC Components Bio-battery Remote Power Source Effective for Sea Water W Conclusion Acknowledgements

308 313 314 318 319 320 320 320 320

References

320

17. Vermicomposting: A Potential Tool for Sustainable Management of Solid Waste

329

17.1 Introduction 17.2 Classification and Composition of Solid Waste 17.3 Current Strategies used for Solid Waste Management in India 17.4 Earthworms

333 339

17.5 17.6 17.7 17.8

342 346 348 349

Vermicomposting Process Vermicompost and Earthworm Harvesting Composition of Vermicompost Advantages and Disadvantages of Vermicompost V

329 331

xii

Contents

17.9 Applications of Vermicomposting 17.10 Conclusion References

18. Biogas Potential from Sewage Treatment Plant and Palm Oil Mill Effluent for Electricity Generation in Malaysia

350 350 351

355

18.1 Introduction

355

18.2 Renewable Energy Status in Malaysia and Malaysian Renewable Energy Target

357

18.3 18.4 18.5 18.6 18.7

Feed-in Tariff in Malaysia Malaysian Palm Oil Industry Biogas Potential in Palm Oil Mills Malaysian Sewerage Treatment Typical Sewage Treatment Plant with Anaerobic digester Scenario in Malaysia 18.8 Biogas Potential at STP 18.9 Co-digestion of Pome with SS

18.10 Impact of Biogas Recovery on Sustainability 18.11 Conclusion Acknowledgements References

19. Passive Energy in Residential Buildings

358 360 363 364 365 368 370 372 373 373 374

377

19.1 Introduction 19.2 Passive Solar Cooling

377 380

19.3 Methodology 19.4 Estimation of Energy Cost 19.5 Conclusion References

386 391 393 393

20. Solar Photocatalytic Treatments of Wastewater and Factors Affecting Mechanism: A Feasible Low-cost Approach 20.1 20.2 20.3 20.4 20.5 20.6 20.7

Introduction Solar Spectrum Design of Solar Photocatalytic Reactors Photocatalytic (Solar) Treatment of Pollutant Factors Affecting Solar Photocatalysis Recommended Analytical Methods Economical Assessment

399

399 400 402 406 413 419 420

Contents

20.8 Conclusion References

21. Advancement in Phase Change Materials for Solar Thermal Energy Storage

xiii 420 421

427

21.1 Introduction 21.2 Phase Change Materials 21.3 Application of PCMS

427 428 432

21.4 Conclusion References

450 452 5

22. Earth to Air Heat Exchanger Systems for Small Houses and Industrial Buildings in Changing Indian Climatic Conditions

459

22.1 Introduction 22.2 Changing Indian Climatic Conditions 22.3 Indian Climate and EAHE Systems

459 460 464

22.4 22.5 22.6 22.7 22.8 22.9

466 470 471 473 473 476 477

Demand for Energy in India Advantages of EAHE System Design of EAHE Systems Components of EAHE System Performance of EAHE System Conclusion References

23. Development in Metal Oxide Nanomaterial-based Solar Cells 23.1 23.2 23.3 23.4 23.5 23.6 23.7 23.8 23.9 23.10

Introduction History of Solar Cell Metal Oxide Nanomaterials Three Generations of Development Nanomaterial-based Solar Cell Research Thin Film Solar Cells Applications and Implementations Polymer Solar Cells PV V Industry Goal: Reduce Cost of Energy Conclusion References

Index About the Editors

479 479 480 481 482 484 486 488 490 490 490 492 497 521

CHAPTER

1 Biogas Potential in India: Production, Policies, Problems, and Future Prospects Sohini Singh, Barbiee Choudhary, Stebin Xavier, Pranita Roy, Neeta Bhagat, and Tanu Allen* Amity Institute of Biotechnology, Amity University, Noida * E-mail: [email protected]

1.1

INTRODUCTION

India has a high requirement for energy because of its large population. Although energy generation in India is less than energy demand, till now these demands were met by the use of forests resources. Moreover, with the global crunch in fossil fuel reserves, this demand is growing at a yearly rate of 4.6% (Ramachandra, Vijay, Parchuri, et al. 2006). According to Mourad, Ambrogi, and Guerra (2004), around 10%–14% global energy is contributed through biomass. Although the government is exploring the field of energy source and production, security of energy supply, and reduction in carbon dioxide (CO2) emission, biomass appears to be the most promising energy source. First, biomass is a renewable source of energy. Second, transforming biomass to bioenergy such as biogas through anaerobic digestion method is precisely known, and in developing countries it has been used as a source for cooking and lighting (Omer and Fadalla 2003). Anaerobic digestion not only provides biogas energy but also manages and stabilizes organic wastes, converting them into nutrient-rich matter which can be used as a natural fertilizer and soil conditioner. Biogas is a cheap, clean, renewable, naturally produced, and underutilized energy source (Verstraete, Morgan-Sagastume, Aiyuk, et al. 2005). It weighs 20% less than air and ignites at the temperature range from 650°C to 750°C (Kohler, Hellweg, Recan, et al. 2007). It burns giving a blue flame and is a colourless and odourless gas (Mandal, Kiran, and

2

Emerging Energy Alternatives for Sustainable Environment

Mandal 1999). Its caloric value is 20 MJ/m3 (FAO 1997) and usually burns in a conventional biogas stove with 60% efficiency. Therefore, the need of the hour is a renewable, eco-friendly, green energy source that can also cater to the energy demands of ever-growing population. This chapter reviews the scenario of Indian biogas generation, policies, and problems faced. Applications and future prospects of biogas technology have also been discussed.

1.2

PRODUCTION OF BIOGAS

Biogas is generated by anaerobic digestion. It is important to convert biodegradable waste into useful fuel, thus reducing the volume of waste products. Anaerobic digestion also assists in killing disease-causing pathogens. In anaerobic digestion, microorganisms digest organic materials in the absence of oxygen, airtight condition, and at a certain level of moisture, temperature, and pH (Angelidaki, Ellegaard, and Ahring 2003; Buren 1983). It is a multi-step biological process of acidogenesis, acetogenesis, hydrolysis, and methanogenesis in which the organic carbon gets converted into CO2 and methane (CH4) (Figure 1.1).

Fig. 1.1

Scheme of anaerobic digestion

Source Angelidaki, Ellegaard, and Ahring (2003)

Biogas Potential in India: Production, Policies, Problems, and Future Prospects

1.2.1

3

Hydrolysis

It is the primary or initial stage of biogas production through anaerobic assimilation. Facultative anaerobes (hydrolytic bacteria) break down complex organic compounds into soluble organic molecules, for example, proteins into amino acids, lipids to fatty acids, and carbohydrates to sugars, by extracellular amylase, cellulase, lipase, or protease enzymes (Parawira, Murto, Read, et al. 2005). During anaerobic digestion, as reported by Vavilin, Rytov, and Lokshina (1996), the presence of large particulate molecules with reduced surface to volume relation / ratio in the substrate may constrain the digestion reaction and make the hydrolysis itself a rate-limiting step.

1.2.2

Acidogenesis

The second step of anaerobic digestion is acidogenesis (Vavilin, Rytov, and Lokshina 1996) in which facultative and obligate anaerobes or anaerobic oxidizers utilize the soluble organic molecules obtained from hydrolysis (Garcia-Heras 2003) and break them further into acetate, hydrogen, and CO2, which yields higher energy for microorganisms. According to Schink (1997) and Angelidaki, Ellegaard, Sorensen, et al. (2002), the products of acidogenesis consists of approximately 19% H2 / CO2, 51% acetate, 30% intermediate reduced products, such as higher alcohols, lactate, or volatile fatty acids (VFAs) which can be used directly by methanogens.

1.2.3

Acetogenesis

In acetogenesis, breakdown of short-chained, alcohols, aromatic fatty acids, and higher VFAs to acetate and H 2 occurs. The products undergo the last step of the biogas production known as methanogenesis.

1.2.4

Methanogenesis

Methanogenesis is the terminal step of anaerobic digestion in which methanogenic archaea converts H 2 / CO 2 and acetate to CO 2 and CH4 (Kotsyurbenko 2005). Kotsyurbenko also reported the use of homoacetogenic bacteria in the CH4 formation pathway, which is dependent upon the concentration of hydrogen in the system that oxidizes or synthesizes acetate.

1.3

SOURCES/MATERIALS FOR BIOGAS PRODUCTION

Resource that is generated from biological organisms and can be tapped for energy uses such as biofuels and biogas is called biomass. A number

4

Emerging Energy Alternatives for Sustainable Environment

of substrates such as peel of corn, soy, wheat and rice, discarded parts of straw or manure from animals or industrial wastes, and even energy crops can be utilized for biogas generation (Ofoefule and Uzodinma 2008; Uzodinma, Ofoefule, Onwuka, et al. 2007). As anaerobic digestion process uses facultative anaerobes for the decomposition of organic matter, environmental conditions and nutrient availability play important roles in the biogas production. The components of biogas (Figure 1.2) may differ depending on the material being decomposed (Anunputtikul and Rodtong 2004). Some of the sources are discussed next.

1.3.1

Food Processing Industrial Wastes

In food processing industries such as fruits, dairy, vegetables, sugar, meat or oil processing, a large amount of waste is generated in both solid and liquid forms. These wastes are organic in nature and have a high content of carbohydrates, lipids, and proteins. With a suitable chemical composition, waste can be used as a substrate for microbiological fermentations. Anaerobic digestion is a popular way of treating these types of wastes (Kaushik, Satya, and Naik 2009).

1.3.2

Sugar Processing Waste

Sugar is produced in 121 countries. About 70% of the produced sugar is from sugar cane and 30% from sugar beets. Processed and unprocessed by-products of beet sugar industry include cut-offs of beet leaves and beet top, molasses, and beet pulp. The sugar extraction process generates a syrup residue known as molasses, and after the desugaring process,

Fig. 1.2

Characteristics of biogas

Source Angelidaki, Ellegaard, and Ahring (2003)

Biogas Potential in India: Production, Policies, Problems, and Future Prospects

5

this residue is known as desugared molasses (DM) (Satyawali and Balakrishnan 2007; Olbrich 1963). Thus, every single lot (tonne) of beet sugar yields 0.33 tonne grass cut-offs, 0.24 tonne DM, and 0.33 tonne beet pulp (Danisco Sugar 2001).

1.3.3

Potato Starch Processing Waste

There has been an increase of about 46 million tonnes in the potato production over the past 40 years in Africa, Asia, and Latin America (FAOSTAT 2010). China and India account for one-thirds of the total potato production in the world. According to Karup Kartoffelmelsfabrik (2002), from per tonne potato flour, which is 20% water and 80% potato starch, 0.73 tonne of potato pulp and 6.6 m3 of potato juice are produced as by-products, rich in both protein and starch. Since these are a biodegradable constituents, they can be utilized for generation of biogas.

1.3.4

Paper Waste

In India, around 18 lakh tonnes of paper is produced every year. Office, schools, factories, printing presses, and so on produce huge amounts of waste paper. Paper waste is considered as a good feedstock for biogas production; therefore, it can be utilized as a source of cheaper energy generation and waste management. Paper waste is treated with animal waste for constant gas flame and this is called co-digestion process (Mshandete, Kivaisi, Rubindamayugi, et al. 2004; Nielsen and Angelidaki 2008).

1.3.5

Poultry Waste

Brazil is the world’s original aviary maker. The poultry litter is a mixture of aviary excreta, uneaten feed and fowl quills. The quality of poultry litter and the amount delivered depend upon the base material used, the season of the year, the creation time, and the populace thickness of the flying creature (Costa, Barbosa, Alves, et al. 2009). The biogas generated from poultry litter can be used as a vitality source. The same gas can be used for inner ignition motors as fuel to produce power. The effluents and strong squanders from anaerobic ageing procedure can be used as compost for obtaining high quantities of vitamins, minerals, and proteins (Rondon 2008).

1.4

ROLES OF MICROBES IN PRODUCTION OF BIOGAS

Nagamani and Ramasamy (1991) compared the microbic diversity in biogas digesters to that of cow rumen and reported about 17 species of fermentative microorganisms that play an important role in the biogas production. Moreover, it is the behaviour of a substrate that determines the kind and

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Emerging Energy Alternatives for Sustainable Environment

extent of the fermentative bacterium that will be within the biodigesters. Much of that bacterium adheres to the substrate before intensive chemical reaction. Some bacteria species involved in fermentation, such as Ruminococcus albus, Bacteroides succinogenes, Clostridium cellobioparum, and Butyrivibrio fibrisolvens are predominant. The cellulase enzymes in the biogas digesters were characterized by Sivakumaran, Nagamani and Ramasamy (1992) and it was reported that Acetivibrio sp. showed higher cellulase activity than that shown by Clostridium and Bacteroides spp. Nagamani, Chitra, and Ramasamy (1994) reported that though obligate hydrogen-producing acetogenic bacterium is less in extent, it is among the important strains in biogas reactors. These organisms release energy as CH4 by oxidizing the longer chain fatty acids. Anaerobic degradation of aromatic compounds depends upon hydrogenconsuming bacterium which acts as the minor species in the biogas digesters during fermentative reactions. Mackie and Bryant (1981) reported a considerable rise in biogas formation by the activity of these organisms, especially Methanosarcina barkeri, a predominant archaebacterium, as acetate is the most important substrate in biodigesters. Among the methanogenic genera, Methanosaeta sp. and Methanosarcina sp., besides producing biogas by acetoclastic reaction, are also useful in stabilizing of the digester.

1.5 ISSUES AND CONCERNS FOR THE BIOGAS PRODUCTION PROCESS Concerns related to the generation of biogas largely depend not only on the nature of the raw material but also on the operational aspect of how the process is carried out. According to Angelidaki and Ellegaard (2003), at times the raw material may be loaded with cations that may act as inhibitors at larger concentrations, or toxic complexes, such as VFAs, which are initially absent in the feed may be generated during the anaerobic course of the digestion process (Angelidaki, Ellegaard, Ahring 2003; Angelidaki, Ellegaard, Sorensen, et al. 2002). Feedstock factors (that is, pH, nutrients, inhibitory compounds, and buffering capacity) and operational settings [that is, both OLR (organic loading rate) and temperature] affect the functioning of microorganisms.

1.5.1

Temperature

Temperature has a major influence on anaerobic digestion as the procedure can be used for temperatures ranging widely between psychrophilic (60°C) as reported by Kashyap, Dadhich, and Sharma (2003) and Lepistö and Rintala (1999). According to Boe (2006), the

Biogas Potential in India: Production, Policies, Problems, and Future Prospects

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advantages of increasing temperature include increased organic compound solubility; increased rate of biological and chemical reaction; improved diffusivity of soluble substrates; increased death rate of pathogenic bacteria, especially when conditions are thermophilic; and increased long-chain fatty acids and VFAs degradation. The disadvantages of high temperature are effects on kinetics and thermodynamics of the biological processes. Two temperature ranges that can provide good digestion conditions for biogas generation are as follows: (i) Mesophilic range: Microbes are called mesophilic when they can function around the temperature range 30–38°C or 20–45°C. (ii) Thermophilic range: Thermophilic bacteria act around temperature range of 49–57°C or up to 70°C (Kangle, Kore, and Kulkarni 2012).

1.5.2

pH and Buffering Capacity (Alkanility)

pH is an important factor and has an effect on the microbial growth throughout the anaerobic fermentation. Microorganisms of different types may act at a similar range of pH or each type of microorganisms has a specific range of pH to grow optimally. According to Hwang, Jang, Hyum, et al. (2004), fermentative bacteria act in the pH range of 4–8.5 (Horiuchi, Shimizu, Tada, et al. 2003). In contrast, methanogenic species, which grow in a specific acidic condition, can work in the relatively limited pH range of 5.5–8.5 (Boe 2006), otherwise their growth can be inhibited in acidic conditions within the digester (Kangle, Kore, and Kulkarni 2012). Only Methanosarcina is able to grow in lower pH values (pH 6.5 and below) compared to others, as the metabolism gets considerably suppressed at pH