Anaerobic fermentation of kitchen wasteThe principle is to decompose organic matter into biogas (mainly composed of methane and carbon dioxide) and stabilize the residue through anaerobic microorganisms in an anaerobic environment.

　　Anaerobic fermentation of kitchen wasteBasic principle:

Anaerobic fermentation is a process in which microorganisms decompose organic matter into simple compounds through a series of biochemical reactions under anaerobic conditions, and ultimately generate biogas. The entire process is completed by the collaboration of multiple anaerobic microorganisms, mainly divided into four stages:

Hydrolysis stage

Function: Decompose large organic molecules (such as proteins, fats, carbohydrates) into small molecular substances.

Process:

Protein → Amino acid

Fat → Fatty acids and glycerol

Carbohydrates → Monosaccharides

Key microorganisms: hydrolytic bacteria (such as Clostridium and Bacillus).

Acidification stage (fermentation stage)

Function: Small molecule substances are further converted into volatile fatty acids (VFA), alcohols, hydrogen, and carbon dioxide.

Process:

Amino acids → Organic acids, ammonia

Monosaccharides → Acetic acid, propionic acid, butyric acid, etc

Key microorganisms: Fermentation bacteria (such as Bacteroides and Bifidobacterium).

Acetic acid production stage

Function: Convert volatile fatty acids and alcohols into acetic acid, hydrogen gas, and carbon dioxide.

Process:

Propionic acid → Acetic acid+Carbon dioxide+Hydrogen gas

Butyric acid → Acetic acid+Hydrogen gas

Key microorganisms: hydrogen producing and acetic acid producing bacteria (such as Pseudomonas aeruginosa).

Methane production stage

Function: Methanogenic bacteria use acetic acid, hydrogen, and carbon dioxide to produce methane.

Process:

Acetic acid → methane+carbon dioxide (accounting for over 70% of methane production)

Hydrogen+carbon dioxide → methane+water

Key microorganisms: Methanogenic bacteria (such as Methanococcus and Methionibacterium).