The bio sludge with approx 2% total solids (TS) is pumped to the decanter for dewatering. A decanter’s normal capacity is around 3.5 m3/h. The bio waste has to be mixed with polymer to create flocculates, so a flocculation pump station adds diluted polymer into the bio waste. The bio waste and polymer are mixed in the decanter centrifuge, forming solids and liquids. The bio waste solids are conveyed out of the decanter at approx 20% DS and drop into the wet waste silo by gravity. The liquid is drained out of the decanter and flows back to the AWP unit.
The bio waste is then pumped from the silo to either an internal dryer in the incinerator or to an external dryer. Similarly to the food waste system, it is possible in emergency situations to pump the bio waste overboard using the overboard discharge system.