Biogas Production

Biogas can be produced by fermenting organic material in absence of air or oxygen with the help of bacteria to break down materials to intermediate stage such as alcohol and fatty acids and finally to methane, carbon dioxide and water this process is called anaerobic fermentation.

A number of stage are involved

Anaerobic digestion programme can be divided in three phases

Phase 1: Hydrolysis

The waste materials of plant and animal origins consist mainly of carbohydrates, lipids, proteins and inorganic materials. Large molecular complex substances are solubilized into simpler ones with the help of extracellular enzyme released by the hydrolysis bacteria. This stage is also known as polymer breakdown stage. For example, the cellulose consisting of polymerized glucose is broken down to dimeric, and then to monomeric sugar molecules (glucose) by cellulolytic bacteria.

Phase 2: Acidification

The sugar molecules produced in phase 1 is fermented under anaerobic condition into various acids with the help of enzymes produced by the acid forming bacteria. At this stage, the acid-forming bacteria break down molecules of six atoms of carbon (glucose) into molecules of lesser atoms of carbon (acids) which are in a more reduced state than glucose. The principal acids produced in this process are acetic acid, propionic acid, butyric acid and ethanol.

Phase 3: Methanization

The acids produced in phase 2 are further processed by methanogenic bacteria in to methane. The reactions that takes place in the process of methane production is called Methanization