Biogas is one of major green energies that are appropriate, renewable and sustainable having least adverse effect on this universe. It was used for heating purpose about 3,000 years ago. Biogas is produced by anaerobic digestion or fermentation of biodegradable materials such as biomass, manure, sewage, municipal waste, green waste, plant residue and energy crops. It is one of the oldest processes used for the treatment of industrial wastes and stabilization of sludges. Since it is carried out by an association of microorganisms and depends on various factors like pH, temperature, HRT, C/N ratio, etc it has minimum environmental loads.
Biogas is the gaseous mixture of Methane (CH4): 60-70 per cent; Carbon dioxide (CO): 30-35 per cent; Nitrogen (N): 1 per cent; Hydrogen (H): 0.1-0.5 per cent; Carbon monoxide (CO): 0.1 per cent; and Hydrogen Sulfide (H2S): traces. It is the methane in this mixture of gases that is combustible.
Increased cost of energy supplies, waste disposal and public awareness regarding environmental quality degradation, the conversion of waste to energy is becoming an economically viable option. The development of alternate energy sources helps to meet energy needs and also reduce the environmental pollution load.