PURPOSE: To rapidly treat heterogeneous waste products consisting of a solid phase and a liquid phase.

CONSTITUTION: This press is composed of a frame 1, a feed zone 3 for receiving waste products, a pressing chamber 9 consisting of an inlet opening 10 and an outlet opening 11 which are in opposed relation and disposed coaxially relative to the feed zone, and a discharging chamber 14 for discharging a solid phase. Also, the press is composed of a member 15 which is movable transversely relative to the axial direction of the pressing chamber between a first position for closing the outlet opening and a second position for opening the outlet opening, and a means 20 for applying the movable member 15 against the outlet opening of the pressing chamber.