Abstract: The apparatus comprises a plurality of stages having screw presses, the material passing out from the outlet side of the stages being passed by a transfer duct to the inlet side of the following stage. Each stage has a speed adjustable independently of the speed of the other stages. Compared with known screw presses, the advantage exists that following each treatment in a stage, by means of an opening in the transfer duct, the material can be measured, checked or subjected to an additional treatment. The number of stages can also be adapted to the material being processed and there is also a relatively large freedom with regards to the arrangement of the apparatus.