Screw press with filter plates

A screw press for separating liquid from a solid-liquid mixture includes a casing having inlet and outlet sections, and a filter section there between. The filter section includes an axially extending stack of coplanar filtration plates defining a core passage for receiving a screw configured to convey the solid-liquid mixture from the inlet section to the outlet section while compressing and dewatering the solid-liquid mixture by forcing at least part of the liquid content of the mixture to be expelled out of the casing through inter-plate gaps defined between each pair of adjacent filtration plates. The filtration plates are fixed relative to one another and clamped in direct intimate face-to-face contact by a clamping assembly operable for applying a predetermined axially clamping pressure substantially uniformly about the core passage. The inter-plate gaps are controlled by the surface roughness of the plates and the clamping pressure.