TECHNOLOGY FOCUS - ENVIRONMENT - Preferred Apparatus: The reaction space includes a thermolysis zone and a gasification zone. The oxygen-containing gas is fed to the thermolysis zone. The thermolysis zone is superimposed to the gasification zone. The reaction chamber has an arcuate shape and the thermolysis zone is located at the concavity of the arcuate shape. The air chamber is situated above the reaction chamber or on one side of it. The waste feed units comprise two waste conduits and two pistons, each coupled to one of the waste conduits. The waste conduits are at right angles to one another. Both waste conduits are horizontal. Alternatively, one of the waste conduits is horizontal and the other is vertical. The apparatus further comprises units for synchronizing the two pistons, units for feeding oxygen-containing gas under pressure to the reaction chamber; and units for discharging the ash comprising a piston, conduit for the ash advanced by the piston, and an outlet. The synchronizing units comprise units for causing one of the pistons to carry out the forward stroke when the other piston carries out its rearward stroke. The reaction chamber is elongated and curved, having its concavity directed towards the oxygen-containing gas feed units and having its convexity directed towards the gas receiving space. An upper section only of the reaction chamber is enclosed in a casing.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Gases: The oxygen-containing gas is air. The fuel gases comprise carbon monoxide and hydrogen.Preferred Method: The method further involves controlling the temperature in the reaction space by units controlling the temperature of the oxygen-containing gas, and controlling the rate of feed of the waste and the resulting ratio of the waste to the oxygen-containing gas. The waste is advanced through the reaction space in the form of an elongated mass. Oxygen-containing gas is fed at high temperature and under pressure to one side of the elongated mass and fuel gases are withdrawn from the other side of the elongated mass.