In an anaerobic environment, the organic substance decomposes with the help of bacteria. Biogas is an intermediate product of their metabolism.
The decomposition process can be divided into 4 phases:
Aerobic bacteria decompose high-molecular substances (proteins, fats, carbohydrates, cellulose) into low-molecular compounds.
Acidification. Individual molecules penetrate bacteria cells, where further transformation takes place. This process takes place under the influence of anaerobic bacteria, which absorb the remaining oxygen to provide acceptable anaerobic conditions for methane bacteria.
Acid-forming bacteria form the starting materials for the formation of methane: acetic acid, carbon dioxide and hydrogen.
The last phase is the formation of methane, carbon dioxide and water. 90% of methane is formed at this stage.