Biogas is a clean gaseous fuel produced through anaerobic digestion of organic
matter present in various urban and industrial wastes. The raw biogas is primarily
composed of Methane (CH4) 55 70% and Carbon Dioxide (CO2) 25 -40% with smaller
amounts of Hydrogen Sulphide (H2S) and Ammonia (NH3). Biogas has been traditionally
used as fuel in the kitchens in its raw form i.e. without any processing. Its use as a fuel for
large boilers and engines was restricted by the H2S content of biogas. During last one
decade, a number of processes for removal of hydrogen sulfide from biogas have been
indigenously developed and equipment and processes are being offered for this purpose by
several Indian Companies. This has resulted in use of biogas for generation of motive
power/electricity at several anaerobic digestion installations in the country for utilizing
biogas for replacing fossil fuels and/or grid electricity