NOVELTY - Assembly for the aerobic fermentation of biological materials, and especially waste and rubbish, has a container (14), at ground level, with air feed lines passing through the base of the container. The outlet is at a gap from the container base, and especially within the lower one-third of the height of the mixed material in the container (14), to pass into the gas take-off lines (44).    USE - The system is for the disposal of biological waste from dwellings, commerce and industry.    ADVANTAGE - The operation degrades the biological matter rapidly, for use in soil cultivation and the like, with a low use of additional energy. The process also gives a fraction which can be used to generate energy.    DETAILED DESCRIPTION - Assembly for the aerobic fermentation of biological materials, and especially waste and rubbish, has a container (14), at ground level, with air feed lines passing through the base of the container. The outlet is at a gap from the container base, and especially within the lower one-third of the height of the mixed material in the container (14), to pass into the gas take-off lines (44). The gas take-off lines (44) take the exhaust gas through a gas washer, after the filter (15a) in the flow direction, for release into the ambient environment, or it is released through a reactor with an oxidizing catalyst, or through a heat exchanger. The air feeds into the container (14) have an upper cover, with a lower opening in the air feed or openings around it. Fluid feeds (41) open into the air feeds, especially with a venturi jet at one outlet opening. The openings at the air feeds have a valve with a rapid closing action, and preferably a magnetic valve. The oxygen supply (44a) is linked to the air feeds and/or a compressed gas supply (44b) through a controlled valve and a faucet. The air feeds are in a channel, below the base of the container (14), with upwards branches as separate air feeds into the container at the base of a conveyor belt or chain, or on both sides of it. The container (14) has a service path over the maximum height of mixed material held in it. The container (14) is covered by a roof. The openings of the gas take-off line (44) are flush with the side walls. The container base has a drain, and at least one channel for the escape of water from the container (14). An additional watering system for the mixed material is over its maximum height within the container (14). The installation has a number of containers (14), with common side walls, with rolling doors to link them together. The container (14) can be fitted with water jets to cut through the material, and a mixing system. In the direction of material movement, a sorting stage is after the container (14) to separate light matter, followed by an incinerator and especially a fluidized bed incinerator.    DESCRIPTION OF DRAWING(S) - The drawing shows a sketch of the waste disposal stages.    container (14)    filter (15a)    fluid feeds (41)    gas take-off lines (44)    oxygen supply (44a)    compressed gas supply (44b)