Biogas: It is a combustible gas produced by the fermentation of microorganisms in an anaerobic environment under certain conditions of temperature, humidity, and pH. Because this gas was originally found in swamps, lakes, and ponds, people call it methane.
Biogas contains a variety of gas components.  The main component is methane (CH4). Biogas bacteria decompose organic matter and produce biogas. It is called biogas fermentation. According to the role of various types of bacteria in the biogas fermentation process, biogas bacteria can be divided into two categories. The first type of bacteria is called decomposing bacteria. Its role is to break down complex organic matter into simple organic matter and carbon dioxide (CO2). Among them are those that specifically decompose cellulose, called cellulolytic bacteria; those that specifically degrade proteins, called proteolytic bacteria; those that specifically decompose fat, called lipolytic bacteria; the second types of bacteria, which are called methane-containing bacteria, commonly called methanogens. Its role is to oxidize or reduce simple organic matter and carbon dioxide to methane. Therefore, the process of converting organic matter into biogas is like the two steps in the production of a product in a factory: first is the decomposition of bacteria to process complex organic matter such as manure, straw, and weeds into semi-finished products - simple structural compounds; Under the action of methane bacteria, simple compounds are processed into products - that is, methane is produced.
Biogas is a mixed gas, its main component is methane, followed by carbon dioxide, hydrogen sulfide (H2S), nitrogen and other components. In the composition of biogas, combustible components include gases such as methane, hydrogen sulfide, carbon monoxide, and heavy hydrocarbons; non-combustible components include gases such as carbon dioxide, nitrogen, and ammonia.