Abstract: Solid waste to be treated is introduced into the interior of a rotary autoclave that is downwardly inclined towards its discharge end and has a door at the discharge end. Steam is injected through said door via a plenum chamber in the door so that water and steam pass through a one-way device and then directly into the interior of the autoclave. The one-way device prevents the solid waste from entering the plenum chamber from the interior of the autoclave. The plenum chamber is defined between a region of the door and a plate secured to the door at a small spacing inwardly of the door. The outlet is defined in the plate and the one one-way device is fitted to the outlet.

Abstract: A method for treating municipal solid waste and other waste is provided which comprises: introducing said waste into a rotary autoclave which is downwardly inclined towards its discharge end and has a door at the discharge end; and injecting steam through said door into said autoclave to treat the load. A method is also provided for treating waste, comprising steam autoclaving the waste, anaerobically digesting an organic-rich fraction of the autoclaved waste, recovering methane-containing gas from anaerobic digestion, internally combusting the methane-containing gas to generate power and exhaust gas, and generating steam for autoclaving using the waste heat.