TMC Fluid Systems Products

What is Anaerobic Digestion?

12.17.2014

Anaerobic Digestion (AD) is a biological process that happens naturally when bacteria is used to break down organic matter in the absence of oxygen. Almost any organic material can be processed with Anaerobic Digestion including grass clippings, leftover food, industrial effluents, sewage and animal waste.

Anaerobic Digestion produces biogas which is typically made up of around 60% methane (CH4) and 40% Carbon Dioxide (CO2). This gas, or more specifically biogas, can be burnt to generate heat or electricity or can be used as fuel for vehicles.

Besides biogas, Anaerobic Digestion also produces a solid and liquid residue called digestate which can be used as a soil conditioner to fertilize land.

The amount of biogas and the quality of digestates obtained vary according to the feedstock used. More gas will be produced if the feedstock is putrescible (i.e. capable of decaying), which means it is more liable to decompose. Sewage and manure yield less biogas as the animal which produced the manure has already taken out some of the energy content.

TMC Fluid Systems supplies Biogas Compressors that are widely used for agitation of the contents of the digester. Biogas Compressors are typically used to recirculate the digestate by sucking the biogas at the top (or at the dome) of the digester and re-injecting it at the bottom of the digester.