The invention relates to a device and a method for the separation of solids from a biowaste slurry before heat treatment, and for heat treatment of the separated solids. The device comprises a chamber with a main inlet port for feeding slurry, and outlet ports. A unit for separating solids is adapted to an outlet port so, that liquid leaving the chamber has passed through the separation unit. A second outlet port is provided directly from the chamber to allow removal, following sterilization, of solids collected in the chamber. The sterilization is secured by temperature monitoring at representative locations.