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© 2008 WILEY-VCH Verlag GmbH & Co. KGaA,
Weinheim
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ISBN 978-3-527-31841-4

Part I General thoughts about energy supply 1
1 Energy supply – today and in the future 3
1.1 Primary energy sources 3
1.2 Secondary energy sources 5
1.3 End-point energy sources 6
1.4 Effective energy 6
2 Energy supply in the future – scenarios 7
2.1 Amount of space 11
2.2 Potential yield from biomass 13
2.2.1 Theoretical potential 13
2.2.1.1 C3 plants (energy plants) 15
2.2.1.2 C4 plants and CAM plants 17
2.2.1.3 Micro-algae 20
2.3 Technical potential 21
2.4 Economic potential 23
2.5 Realizable potential 23
3 History and status to date in Europe 27
3.1 First attempts at using biogas 28
3.2 Second attempts at using biogas 30
3.3 Third attempts at applying biogas 32
3.4 Status to date and perspective in Europe 32
4 History and status to date in other countries 35
4.1 History and status to date in China 36
V
Biogas from Waste and Renewable Resources. An Introduction.
Dieter Deublein and Angelika Steinhauser
Copyright © 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
ISBN: 978-3-527-31841-4
VI Contents
4.1.1 Period from 1970 to 1983 37
4.1.2 Period from 1984 to 1991 38
4.1.3 Period from 1992 to 1998 38
4.1.3.1 “A pit with three rebuildings” 38
4.1.3.2 “4 in 1” 39
4.1.3.3 “Pig-biogas-fruits” 39
4.1.4 Period from the year 1999 onwards 39
4.2 History and status to date in India 40
4.3 Status to date in Latin America 42
4.4 Status to date in the CIS states 42
5 General aspects of the recovery of biomass in the future 45
Part II Substrate and biogas 47
1 Biogas 49
1.1 Biogas compared to other methane-containing gases 49
1.2 Detailed overview of biogas components 52
1.2.1 Methane and carbon dioxide 53
1.2.2 Nitrogen and oxygen 54
1.2.3 Carbon monoxide 55
1.2.4 Ammonia 55
1.2.5 Hydrogen sulfi de 55
1.2.6 Chlorine, fl uorine, mercaptans 56
1.2.7 BTX, PAK, etc. 56
1.2.8 Siloxanes 56
2 Substrates 57
2.1 Liquid manure and co-substrates 57
2.2 Bio waste from collections of residual waste and trade waste similar to
domestic waste 66
2.3 Landfi ll for residual waste 66
2.4 Sewage sludge and co-substrate 70
2.5 Industrial waste water 74
2.6 Waste grease or fat 74
2.7 Cultivation of algae 74
2.8 Plankton 75
2.9 Sediments in the sea 76
2.10 Wood, straw 77
3 Evaluation of substrates for biogas production 79
4 Benefi ts of a biogas plant 83
Contents VII
Part III Formation of biogas 87
1 Biochemical reaction 89
2 Biology 93
2.1 Bioreactions 93
2.1.1 Hydrolysis 94
2.1.2 Acidogenic phase 94
2.1.3 Acetogenic phase 96
2.1.4 Methanogenic phase 98
2.2 Process parameters 100
2.2.1 Parameter: hydrogen partial pressure 101
2.2.2 Parameter: concentration of the microorganisms 102
2.2.3 Parameter: type of substrate 102
2.2.4 Parameter: specifi c surface of material 103
2.2.5 Parameter: disintegration 106
2.2.6 Parameter: cultivation, mixing, and volume load 110
2.2.7 Parameter: light 112
2.2.8 Parameter: temperature 112
2.2.9 Parameter: pH 113
2.2.10 Parameter: redox potential 116
2.2.11 Parameter: nutrients (C/N/P-ratio) 116
2.2.12 Parameter: trace elements 116
2.2.13 Parameter: precipitants (calcium carbonate, MAP, apatite) 117
2.2.14 Parameter: biogas removal 117
2.2.15 Parameter: inhibitors 118
2.2.15.1 Oxygen 119
2.2.15.2 Sulfur compounds 119
2.2.15.3 Organic acids (fatty acids and amino acids) 121
2.2.15.4 Nitrate (NO3
−
) 122
2.2.15.5 Ammonium (NH4
+
) and ammonia (NH3) 123
2.2.15.6 Heavy metals 125
2.2.15.7 Tannins 125
2.2.15.8 Other inhibiting thresholds 125
2.2.16 Parameter: degree of decomposition 127
2.2.17 Parameter: foaming 127
2.2.18 Parameter: scum 127
3 Bacteria participating in the process of degradation 129
3.1 Hydrolyzing genera 131
3.2 Acidogenic genera 131
3.3 Acetogenic genera 134
3.4 Methanogenics 135
3.5 Methanotropic species 137
VIII Contents
Part IV Laws and guidelines concerning biogas plants 149
1 Guidelines and regulations 151
1.1 Construction of plants 152
1.1.1 Corresponding regulations 152
1.1.2 Checklist of regulations concerning the plant 154
1.2 Utilized biomass 155
1.3 Biomass to be used preferentially 159
1.4 Distribution of the residues 160
1.5 Feeding biogas to the gas network 161
1.6 Risk of explosion 161
1.6.1 Explosion-endangered areas – ex-zones 162
1.6.2 Checklist of measures for explosion protection 164
1.7 Risk of fi re 171
1.7.1 Fire protection sectors 171
1.7.2 Checklist for fi re protection measures 172
1.8 Harmful exhaust gases 173
1.8.1 Prescriptions and guidelines 173
1.8.1.1 Germs 175
1.8.1.2 Emissions of smells 175
1.8.2 Checklist for immission prevention measures 179
1.9 Noise protection 183
1.9.1 Regulations and guidelines 184
1.9.2 Checklist for noise protection measures 185
1.10 Prevention of injuries 185
1.11 Protection from water 186
1.11.1 Regulations and guidelines 186
1.11.2 Checklist for water protection measures 186
2 Building a biogas plant 189
2.1 Feasibility study 189
2.2 Preliminary planning 189
2.3 The construction process 192
3 Financing 195
Part V Process engineering 197
1 Parts of biogas plants 199
1.1 Tanks and reactors 199
1.1.1 Brick tanks 199
1.1.2 Reinforced concrete tanks 200
1.1.3 Tanks of normal steel sheet metals with enamel layer or plastic
coating 205
1.1.4 Tanks of stainless steel 206

Rising crude oil prices force us to think about alternative energy sources. Of the
different technologies, solar energy is considered the most effective, and can even
afford the environmental protection of plants. Many visionaries think that rather
biomass will probably convert the solar energy best and will replace all fossil
energy resources in the future.
In the last decades, many companies have erected biogas plants worldwide. A
lot of experience was gained, leading to a continuous process optimization of
anaerobic fermentation and the development of new and more effi cient applications. Overall, the basic knowledge of biogas production, the microorganisms
involved, and the biochemical processes was widely extended.
This knowledge and the new ideas have now been put together as a basis for
the initiation of discussions. Since the technological solutions of technical problems in the fi elds of anaerobic digestion are tending to vary according to the
material treated, e.g., waste water, sewage sludge, or agricultural products, sometimes without any good reason, this book is hoped to contribute to the consolidation of knowledge in the different fi elds, so that learning can be accessed more
easily and applications can be harmonized.
The book includes detailed descriptions of all the process steps to be followed
during the production of biogas, from the preparation of the suitable substrate to
the use of biogas, the end product. Each individual stage is assessed and discussed
in depth, taking the different aspects like application and potential into account.
Biological, chemical, and engineering processes are detailed in the same way as
apparatus, automatic control, and energy or safety engineering. With the help of
this book, both laymen and experts should be able to learn or refresh their knowledge, which is presented concisely, simply, and clearly, with many illustrations.
The book can also be used for reference, and includes many tables and a large
index. It is strongly recommended to planners and operators of biogas plants, as
it gives good advice on how to maximize the potential of the plant.
Originally I collected data and information about biogas plants just out of curiosity. I wanted to know all the details in order to comprehensively teach my students
at the University of Applied Sciences in Munich. For fi ve years I surfed the internet
and read many books, patents, and magazines, and also approached many
companies and manufacturers of plant components, who kindly shared their