NOVELTY - The waste reduction and conversion method involves supplying a substantially continuous flow of substantially inert gas such as the exhaust from combustion of syngas in an internal combustion engine (17) through a substantially inert gas zone (1), a reducing zone (3-5) of syngas separated from an oxygenating gas, such as air by the inert zone, and a barrier layer (7) separating the inert zone and reducing zone. The flow of gas across the barrier layer is reduced by ensuring that the pressure on one side of barrier layer is substantially the same as that on the other side of barrier layer.    USE - Waste reduction and conversion method for heating waste, such as organic waste, in a reaction vessel and collecting syngas used for fueling an engine, such as gas engine. Uses include but are not limited to wood, woodchips, bark, vines, tree branches, acorns, husks, skip waste, and waste containing hydrocarbons.    ADVANTAGE - Adds filtering for syngas, and for exhaust gases from an engine, in which the added filters do not suffer from blockage due to the build up of matter, and where the added filters do not require the provision or periodic replacement of a specially provided filter material. Provides some heat to the waste in a waste to energy converter, thus making it easier to ignite and maintain the combustion of the waste. Provides a zone of substantially inert gas which can be interposed between the zone containing inflammable pyrolysis gas, and the air, thus preventing mixing, unwanted combustion, or even dangerous explosion. Controls the gas flows and therefore the pressure so that the top of the column may be controlled so as to be at near atmospheric pressure, simplifying the entry of new waste into the top of the converter column. Balances the gas flows and therefore the pressure differences along a converter column so that the bottom of the column may be controlled so as to be near atmospheric pressure, simplifying the removal of ash from the bottom of the converter column.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a process for producing engine fuel from waste combustion; and    (2) a reaction vessel for production of syngas from waste material.    DESCRIPTION OF DRAWING(S) - The drawing shows the side elevation of the system for fueling an engine from waste applied to polishing of synthesis gas.    Inert gas zone (1)    Reducing zones (3-5)    Barrier layer (7)    Internal combustion engine (17)    Scrubber (19)