The present invention relates to an apparatus and method for processing of waste and in particular processing involving a volumetric reduction of waste materials. There is an apparatus for processing waste material comprising a compaction compartment for receipt of waste material, the compaction compartment have a screw vane for processing waste material through the compaction compartment and a waste material outlet. In one aspect the apparatus comprises a heating zone including an arrangement for heating the waste material received from the waste outlet, the apparatus further comprising a cooling zone including a cooling arrangement for cooling the waste material received from the heating zone. In another aspect, at least one of the screw vane or wall comprises one or more ports therein for transfer of liquid from the waste material, the one or more ports having a port inlet and a port outlet, wherein the area of the opening defined by the port inlet is different to the area of the opening defined by the port outlet. In a further aspect, a heating zone for receiving waste material from the waste material outlet is provided where the heating zone includes an arrangement for heating the waste material in the heating zone, and a blocking element for impeding movement of waste material from the heating zone.