Biogas is a mixture of different gases produced by anaerobic decomposition (with methanogen or anaerobic organisms), or fermentation, of biomass – organic material (including animal dung, human sewage, food waste, crop residues, and industrial and municipal wastes). Biogas is a renewable energy source. It is composed primarily of methane (up to 60%), which is the combustible component, carbon dioxide, and hydrogen sulfide.
Biogas has a high calorific value and can be converted into electricity and heat. The residue of fermentation is digestate, a liquid material, completely odorless and with a very high agronomic value, with improved characteristics compared to the starting material.
Biogas is produced in an air-tight container, called an anaerobic digester, biodigester or a bioreactor. Is used as a fuel to heat stoves, lamps, run small machines, and to generate electricity. The residues of biogas production are used as a low-grade organic fertilizer. Biogas fuels do not usually cause any pollution to the atmosphere, and because they come from renewable energy resources they have great potential for future use.