Anearobic digestion is a collection of processes by which microorganisms break down biodegradable material in the absence of oxygen. The process that takes place inside The swill (organic end product of the wet food depackaging and kerside waste recycling systems) and/or any other organic material that is used as input in the digester tank. The digester tank is kept at about 40 degrees Celsius where bacteria digest the organics and produce biogas (methane and CO2). The produced biogas can be used for several purposes:
1. Green electricity and heat production. The biogas goes to a CHP engine (Combined Heat & Power engine) where approximately 42% is turned into renewable green electricity by the generator and from the engine cooling water circuit and exhaust approximately 43% is turned into renewable green heat. The renewable green energy can be distributed on the grid and the renewable heat can be used for heating the process, greenhouses, home and / or farm, district heating and drying the digestate.
2. The biogas goes to an installation to get rid of H2S and a big part of the CO2. When it reaches the specifications it is pumped into the gas network as green gas or compressed (CBG)/liquefied (LBG) to be used as vehicle fuel.
The digestate (remaining products after digesting of the organic products) can be used as fertilizer.