What is biogas ? How is the use of biogas is beneficial ?

Explanation

Biogas is a fuel gas produced by decomposition of cow-dung, agricultural wastes, vegetable wastes and sewage in absence of oxygen.
Since the starting material is mainly cow- dung, it is popularly known as gobar gas.
The use of biogas is beneficial as it is considered as an excellent fuel. It contains `75%` methane and burns without smoke leaving no residue. Its heating capacity is high.
Biogas is used for lighting, for cooking. The slurry left behind is removed periodically and used as excellent manure, rich in nitrogen and phosphorous. It is a safe and efficient method of waste-disposal that utilises large amount of bio-waste and sewage material besides supplying energy and manure.