What is Anaerobic Digestion?

What is anaerobic digestion? Turning organic waste into biogas. This process is sustainable. It produces more energy than it consumes. It provides renewable energy. It creates biogas, but there is no need to stop there! Biogas can provide the raw material for transport fuels. Mostly the biogas is burned in an engine to produce electricity. The remaining heat can be used to heat greenhouses and homes etc. (AgStar Program, USEPA). CHP: A plant makes use of the residual heat from the generator/engine. (Combined Heat Power) Now let's look at the Process Flow Diagram. The process starts with an organic waste material. This can be agricultural waste (e.g. sludges), Municipal Solid Waste, or another biological feed. Now let's look at each step in the anaerobic digestion process in turn. We shall show examples of Agricultural and MSW anaerobic digestion plants, but sewage sludges, organic industrial sludges, and even bio-crops can be used. The waste material is fed into a digester which produces methane. A liquid (or liquor) and a fiber are also produced. The waste feed material is delivered and any processing such as recycling is carried out. Fermentation takes place in the Digester, producing methane biogas. It takes 1 to 2 weeks. The digester is normally the largest tank. Biogas is produced and is held in a storage vessel. The liquor may be sold as fertilizer. The fiber may be sold, or composted in the open. The biogas can be compressed and cleaned for use as vehicle fuel. This biogas can be used to fuel cars, trucks, buses and even trains! A turbine or generator produces electricity which is supplied through a meter to the grid. Biogas can also be sent to a boiler on-site or in a nearby factory. What is anaerobic digestion? The End.

The basics of biogas production

Anerobic Digestion: What is it?

Anaerobic Digestion Video Transcript