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close this bookBioconversion of Organic Residues for Rural Communities (UNU, 1979)
close this folderBiogas generation: developments. Problems, and tasks - an overview
View the document(introductory text...)
View the documentIntroduction
View the documentWhat is biogas?
View the documentMicrobiology of CH4, or bio-methanogenesis
View the documentThe biogas plant-some technical considerations
View the documentEnvironmental and operational considerations
View the documentDevelopments and processes for rural areas
View the documentCost-benefit analyses
View the documentHealth hazards
View the documentBottlenecks, considerations, and research and development
View the documentReferences
View the documentDiscussion summary

What is biogas?

Methane is the main constituent of what is popularly known as biogas. A colourless, odourless, inflammable gas, it has been referred to as sewerage gas, klar gas, marsh gas, refuse-derived fuel (RDF), sludge gas, will-o'-the-wisp of marsh lands, fool's fire, gobar gas (cow dung gas), bioenergy, and "fuel of the future." The gas mixture produced is composed roughly of 65 per cent CH4, 30 per cent CO2, and 1 per cent H2S. A thousand cubic feet of processed biogas is equivalent to 600 cubic feet of natural gas, 6.4 gallons of butane, 5.2 gallons of gasoline, or 4.6 gallons of diesel oil. For cooking and lighting, a family of four would consume 150 cubic feet of biogas per day, an amount that is easily generated from the family's night soil and the dung of three cows. In addition, rural housewives using the biofuel are spared the irritating smoke resulting from the combustion of firewood, cattle dung cakes, and the detritus of raw vegetables (Figure 1).



Figure. 1. The Attributes of Biogas as a Fuel vs. the Disadvantages of Wood (Source: Bio-Gas Newsletter, August 1976)