Biomass refers to those living and non-living organic materials that can be used as sources of energy in the form of fuel. Some examples of biomass fuels are biogas, wood, crops, and organic garbage. The chemical energy in biomass is released as heat on burning.
Bio-mass refers to the organic fuel obtained from plants and animal wastes like wood, cow-dung, residue after harvesting the crop, vegetable waste and sewage, etc. It has been used as a fuel for a long time. These fuels, however, do not produce much heat on burning and a lot of smoke is given out when they are burnt.
When substance likes cow-dung, vegetable waste etc undergoes anaerobic (in absence of air) decomposition then these complex substances are broken down into simpler substances and gases like methane, Carbon dioxide etc are produced.
The plant has a dome-like structure built with bricks. A slurry of cow-dung and water is made in the mixing tank from where it is fed into the digester. The digester is a sealed chamber in which there is no oxygen. Anaerobic micro-organisms that do not require oxygen decompose or break down complex compounds of the cow-dung slurry. It takes a few days for the decomposition process to be complete and generate gases like methane, carbon dioxide, hydrogen and hydrogen sulphide. The bio-gas is stored in the gas tank above the digester from which they are drawn through pipes for use.