Aerobic means in the presence of oxygen. In compostingComposting is the controlled aerobic, or oxygen-requiring, decomposition of organic materials by microorganisms, under controlled conditions. It reduc... More, which is an aerobic process, microorganisms access the present oxygen from the surrounding atmosphere. They metabolize the organic material to energy, CO2, water and cell biomassMaterial of biological origin excluding material embedded in geological formations and material transformed to fossilised material. This includes orga... More, whereby part of the energy of the organic material is released as heat. [bM 03/07, bM 02/09]