The dewatering screw is continuously fed with wet and pre-shredded material. Afterwards this material is pushed to the drying chamber and at the same time compressed with the help of a screw with a conical profile. The necessary counterpressure needed for dewatering is applied by a hydraulic ram. The squeezed water leaves the screw through the screen basket placed at the circumference of the screw. The dried material is discharged at the outlet at the upper end of the screw.