Abstract: An autoclave (1) comprises a carrier framework (4) within which a drum (8) is rotatably mounted and rotated by a drive motor (12). The drum (8) defines a hollow interior region within which the waste material is treated, and an open mouth (15) at one end of the drum (8) is closed by a hingedly mounted closure member (16). The carrier framework (4) is pivotally coupled to a ground engaging mounting framework (2) by decoupleable first and second pivot mountings (5,6) at respective opposite ends (10,11) of the carrier framework (4) so that on release of the second pivot mountings (6) the carrier framework (4) and the drum (8) are pivotal about the first pivot mountings (5) by first main drive rams (19) from a horizontal operating state to an inclined loading state with the drum (8) inclined upwardly to the open mouth (15) for loading waste to be treated into the drum (8).