Purification Technologies for Biogas Generated by Anaerobic Digestion

Abstract

Biogas is produced in many different environments, including in landfills, sewage sludge and during anaerobic degradation of organic material. Biogas is comprised of methane (CH4, about 45-75% by volume), carbon dioxide (CO2, 25-55%), and other compounds including hydrogen sulfide (H2S, present in concentrations from several hundred to a couple of thousand parts per million), water, and other trace gas compounds. Methane is a powerful greenhouse gas if emitted into the atmosphere, but can also represent a valuable renewable energy source, with the potential to reduce GHG emissions when it is collected and substituted for fossil fuels.