Biogas

Biogas is a gas produced by the digestion in an oxygen free (anaerobic digestion) or fermentation of organic matter. The organic matter can be manure, sewage, municipal waste, compost, food waste or any other biodegradable raw material. Biogas is mainly methane and carbon dioxide. Depending on where it is produced, biogas is also called:

 swamp gas  
 marsh gas
 landfill gas
 digester gas

Biogas can be used as a vehicle fuel or to generate electricity. It can also be burned directly for cooking, heating, lighting, process heat and absorption refrigeration.

 Biogas and anaerobic digestion 

Anaerobic digestion is much used to make biogas from biodegradable waste because valuable fuel can be produced while destroying disease-causing pathogens and reducing the volume of disposed waste products.  The methane in bio gas burns more cleanly than coal, and produces more energy with less emissions of carbon dioxide.  The harvesting of bio gas is an important role of waste management because methane is a greenhouse gas with a greater global warming potential than carbon dioxide.  The carbon in bio gas was generally recently extracted from the atmosphere by photosynthetic plants, so releasing it back into the atmosphere adds less total atmospheric carbon than the burning of fossil fuels.

 Biogas typical composition range 

The composition of biogas varies depending on how it is made.  Landfill gas typically has methane concentrations around 50%. Advanced waste treatment technologies can produce biogas with 55-75%CH4.

+ Biogas compositionBasic Information on Biogas Matter %  Methane, CH4  50-75  Carbon dioxide, CO2 25-50  Nitrogen, N2  0-10*  Hydrogen, H2  0-1 Hydrogen sulphide, H2S  0-3  Oxygen, O2  0-2* 

 often 5% of air is introduced to get rid of sulfur microbiologically

 Related pages 
 Producer gas

 Other websites 
 AGORES - Biogas Biofuel Lille  (PDF)
 AGORES - Biogas Biofuel Stockholm  (PDF)
 University of Adelaide - An Introduction to Biogas 
 Biogas in Rural Costa Rica 
 Solid Waste Association of North America
 Landfill Gas Symposium 

 References 

Category:Biofuels