Biogas is the result of the controlled microbial breakdown of organic materials such as animal manures or food scraps in an anaerobic digester. An anaerobic digester is operated at a controlled temperature, pH and loading rate to encourage the growth of microorganisms that eat the organic matter and produce biogas and a more biologically stable liquid effluent. Biogas is a mixture of about 60-70% methane (natural gas), 30-40% carbon dioxide and other trace gases, such as hydrogen sulfide. The heat content is based on the amount of methane and is about 600 BTUs per cubic foot.
For more: see Introduction to Biogas and Anaerobic Digestion
Authored by: Robert E. Graves PSU
http://www.biogas.psu.edu
