What Is a Biodigester ?

A biodigester is an anaerobic digestion system which breaks down organic waste including compost, manure or sewage waste. Biodigesters produce methane gas as a by-product of the decomposition process that can be used for fuel.

A biodigester is also known as a biogas device or an anaerobic digester. Biodigesters are used in household and large scale industrial settings as a form of renewable energy and sustainable waste management. A biodigester system includes a closed tank with a decomposition space for the organic materials and a valve system which can be opened to release the methane gas and control the pressure within the tank. The organic waste is filled and decomposes in the bottom of the device. In the oxygen-free environment of the tank, bacteria break down the waste material.

Decomposition goes through multiple stages, and certain types of acid producing bacteria and methane forming archaea (microorganisms) are essential for the decomposition process. When fully decomposed, the waste is used as compost and fertilizer. Methane gas, carbon dioxide and other gases rise to the surface and can be collected from the valve above and used as a fuel source. The gas can be used directly in heat and power gas engines or it can be further refined into natural gas quality bio-methane. Anaerobic digesters are widely used as a renewable energy source and are growing in popularity throughout the globe.