Clean feedstock for biogas production.
The Doppstadt Screw Press separates source separated organic waste, overlaid packaged food stuff as well as kitchen and catering waste into a solid and liquid phase. The bioavailable components are concentrated in the liquid phase and can be used as biogas substrate in a wet fermenter. The input is fed into the mixing hopper by wheel loader or other handling equipment. Two counter-rotating mixing screws gently open up the packaging by shear stress without producing small shreds of plastic. The disintegrated waste is then taken over by the pressing screw which conveys the material against the hydraulically activated pressing cone and thus builds up pressure in the process chamber. If the pressure rises above the pre-set value, the cone opens accordingly and more material gets discharged. Since the cone rotates with the screw shaft, the circumferential gap is always in motion and clogging is prevented. Due to the careful disintegration and pressing, the liquid biogas substrate does not require any further treatment and already contains less than 0.5% contamination based on dry matter prior to the fermenter. The solid phase mainly consists of packaging material and other solids.