Apparatus for pyrolyzing or gasifying the organic content of material, including organically coated waste, biomass, industrial waste, municipal solid waste and sludge, having organic content; the apparatus comprising: an oven having a rotatable portion comprising a treatment chamber adapted to receive material for treatment; a plurality of gas inlets in at least one wall (5) of the treatment chamber through which hot gases are introduced to the treatment chamber to heat the material therein so as to cause the organic components thereof to pyrolyze or gasify; and a plurality of pockets (8) having open faces turned inwardly towards the inside of the treatment chamber on at least one wall of the rotatable portion such that, in use, material being pyrolyzed or gasified can be received from the treatment chamber into the plurality of pockets (8) via said open faces, and be substantially retained therein through an initial rotation of the oven of less than 90 degrees.