A biodigester is a structure constructed under the ground, made with cement, brick/stone, sand and pipes & appliances to decompose organic material and produce biogas- to supplement conventional fuel sources; and bioslurry- to apply as organic manure in the farms. By feeding the recommended amount of cattle dung/pig manure and water every day in the digester, clean gas is produced. This fuel is used mainly for cooking and lighting purposes where as the digested slurry is used in vegetable gardens and agricultural fields.

For many years rural families around the world have used bio-digesters to convert readily accessible animal or plant waste into gas fuel. Bio-digesters use a process of oxygen free decomposition in which bacteria in the animal or plant waste produce a mixture of methane, carbon dioxide, and other gasses that are stored inside. Bio-digesters are relatively simple to build and operate, and require little more than a steady supply of organic matter and water.

The Appropriate Rural Technology Institute (ARTI) is an NGO based in Maharashtra, India. ARTI has developed a compact biogas plant which uses waste food rather than manure as feedstock, to supply biogas for cooking. The compact plants are made from cut-down high-density polythene (HDPE) water tanks, which are adapted using HDPE or PVC piping.