Biogas is a gas produced by the 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:

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

Bio gas production by anaerobic digestion is popular for treating 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 upon how it is made. Landfill gas typically has methane concentrations around 50%. Advanced waste treatment technologies can produce biogas with 55-75%CH4.[1]

Biogas composition[2]
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*

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