(DE4322688-A1)      Composting of organic matter, esp. waste (e.g. domestic or similar waste) by microbial breakdown while supplying a mixt. of pure O2 and waste air, comprises: (a) re-supplying the CO2 present in the waste air to the composting material; and (b) sepg. the water content from the waste air to leave the composting material. Also claimed is an appts. for carrying out the above process, consisting of a closed container with air feed and exhaust equipment, through which the waste air is re-supplied to the container, where a waste air-filter is not provided.    ADVANTAGE -   The process avoids the costs of CO2 removal from the waste air without deleterious effect on microbial breakdown by the increasing CO2 content in the waste air circuit.    (DE4322688-C2)      Organic materials (rotting goods) are composted in a closed container supplied with air, and off-gas from the container is recycled to the rotting goods. Water is sepd. from the off-gas.    Pref. the amt. of gas recycled per unit time is increased as the temp. in the rotting goods rises and decreased as the temp. drops. The temp. in the rotting goods is at least 60 deg.C. The water is sepd. in a heat exchanger and the heat recovered used to generate electricity.    USE/ADVANTAGE -   Used for composting household waste, etc. Method is shorter and more effective.    (EP633235-B1)      Composting of organic matter, esp. waste (e.g. domestic or similar waste) by microbial breakdown while supplying a mixt. of pure O2 and waste air, comprises: (a) re-supplying the CO2 present in the waste air to the composting material; and (b) sepg. the water content from the waste air to leave the composting material. Also claimed is an appts. for carrying out the above process, consisting of a closed container with air feed and exhaust equipment, through which the waste air is re-supplied to the container, where a waste air-filter is not provided.    ADVANTAGE -   The process avoids the costs of CO2 removal from the waste air without deleterious effect on microbial breakdown by the increasing CO2 content in the waste air circuit.