Table of Contents
Biogas Basics ...................................................................................................................................... 4
What is biogas?............................................................................................................................................... 4
Biogas and the global carbon cycle ................................................................................................................ 4
Biology of methanogenesis............................................................................................................................. 4
Substrate and material balance of biogas production...................................................................................... 4
Composition and properties of biogas ............................................................................................................ 4
Utilization ....................................................................................................................................................... 5
The Benefits of Biogas Technology ............................................................................................................... 5
The Costs of Biogas Technology.................................................................................................................... 6
Fuel and Fertilizer........................................................................................................................................... 6
Public and Political Awareness....................................................................................................................... 6
History of Biogas Technology ........................................................................................................... 7
Europe/Germany............................................................................................................................................. 7
China and India............................................................................................................................................... 7
German promotion of biogas technology in the south .................................................................................... 7
Outlook ........................................................................................................................................................... 8
Microbiology ...................................................................................................................................... 9
The three steps of biogas production .............................................................................................................. 9
Hydrolysis....................................................................................................................................................... 9
Acidification ................................................................................................................................................... 9
Methane formation........................................................................................................................................ 10
Symbiosis of bacteria.................................................................................................................................... 10
Parameters and process optimisation ............................................................................................ 11
Substrate temperature ................................................................................................................................... 11
Available nutrient ......................................................................................................................................... 11
Retention time............................................................................................................................................... 12
pH value........................................................................................................................................................ 12
Nitrogen inhibition and C/N ratio ................................................................................................................. 12
Biodegradable material ................................................................................................................................. 13
Substrate solids content and agitation........................................................................................................... 14
Inhibitory factors .......................................................................................................................................... 14
The Physical Appearance of Different Types of Biogas Plants.................................................... 16
Balloon plants ............................................................................................................................................... 16
Fixed-dome plants ........................................................................................................................................ 17
Floating-drum plants..................................................................................................................................... 17
Biogas Appliances ............................................................................................................................ 19
Gas cookers/stoves........................................................................................................................................ 19
Biogas lamps................................................................................................................................................. 20
Radiant heaters.............................................................................................................................................. 22
Incubators ..................................................................................................................................................... 22
Refrigerators ................................................................................................................................................. 23
Biogas-fueled engines................................................................................................................................... 23
Organic Fertilizer from Biogas Plants........................................................................................... 26
Organic substances in fertilizers ................................................................................................................... 26
Nutrients and soil organisms......................................................................................................................... 26
Reduction of soil erosion .............................................................................................................................. 26
The Contribution of Biogas Technology to Conservation and Development ............................. 28
Conservation ................................................................................................................................................. 28
Development................................................................................................................................................. 28
Limitations of Biogas Technology .................................................................................................. 30
Biogas - Framework Conditions..................................................................................................... 32
Social aspects in the planning process .......................................................................................................... 32
Social and political aspects in the dissemination process ............................................................................. 32
Specific regional developments .................................................................................................................... 32
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