production of biogas

the composition of biogas varies depending upon the origin of the anaerobic digestion process. Landfill gas typically has methane concentrations around 50%. Advanced waste treatment technologies can produce biogas with 55%–75% methane,^[10] which for reactors with free liquids can be increased to 80%-90% methane using in-situ gas purification techniques.^[11] As produced, biogas contains water vapor. The fractional volume of water vapor is a function of biogas temperature; correction of measured gas volume for water vapor content and thermal expansion is easily done via simple mathematics which yeilds the standardized volume of dry biogas

Typical composition of biogas

Compound	Formula	%
Methane	CH 4	50–75
Carbon dioxide	CO 2	25–50
Nitrogen	N 2	0–10
Hydrogen	H 2	0–1
Hydrogen sulphide	H 2S	0–3
Oxygen	O 2	0–0