A screw press separator is provided herein for separating and deliquifying a slurry of solids and liquids e.g., a slurry of manure and water, or any other slurry of similar physical characteristics. The separator includes a cylindrical housing having a slurry inflow port. A cylindrical strainer basket extends rearwardly from the housing for the passage of separated liquid therethrough. A cylindrical discharge chamber extends rearwardly from the outlet end of the strainer basket to define a solids discharge opening. A motor driven auger is disposed within the housing and the strainer basket, the auger including a shaft extending through the housing, through the strainer basket and through the cylindrical discharge chamber, for driving the auger for advancing the slurry rearwardly within the cylindrical housing. A spring-loaded door assembly which is connected to the shaft, is provided at the exit of the cylindrical discharge chamber. The liquid is removed through the strainer basket and the residual solids are formed into a solid plug. The solid plug is advanced through the cylindrical discharge chamber, but is prevented from rotating by keystocks situated within the cylindrical discharge chamber. Because of the rotation of the auger shaft, the spring-loaded door assembly also rotates. The door assembly is provided with longitudinally-extending tearing bolts to break up the plug. Discrete solids are thereby discharged through the solids discharge opening between the end of the cylindrical discharge chamber and the forward end of the rotating door assembly.