Biogas
Principle:
In a biogas plant the anaerobic microbial degradation (digestion) of the used substrate takes place. This is mostly from water-rich, easy to medium-degradable biomass such as manure, silage (mainly corn silage) or Biowaste. Straw and wood, which primary contain cellulose and lignocellulose, resist degradation under anaerobic conditions and are not useable therefore. Various types of micro-organisms use the complex composite biomass (carbohydrates, fats, proteins and other) as a nutrient and energy. Other than with aerobic decomposition (respiration) the organisms only take advantage of a small part of the contained Energy during the fermentation. Therefore, they must process a relatively large quantity to meet their energy demand. Main products of degradation are the energy-rich methane (CH4) and carbon dioxide (CO2). Because they are gaseous, they are separated from the fermentation substrate and form the main component of biogas. (CO2) is not further oxidized, but can be supplied along with the energy-rich (CH4) in appropriate combined heat and power plant combustion.