Knowledge Base

Anaerobic digestion produces two valuable outputs. The first is biogas, composed primarily of methane and CO₂. It can be used to generate electricity and heat or purified into biomethane (also called renewable natural gas or green gas) for injection into the gas grid or use as transport fuel. The second is digestate: a nutrient-rich residue that remains after digestion. Digestate separation splits this residue into a solid (thick fraction) and a liquid (thin fraction). Both fractions can be post-processed and applied as an organic fertilizer on agricultural land, closing the nutrient cycle. The thick fraction can, with additional post-treatment, also be processed into compost. In some configurations, the CO₂ captured during biogas upgrading can also be recovered and liquefied for industrial or food-grade use.