(DE19600711-A1)      In a waste composting process, the novelty is that: (a) in the first-stage, organic material is rinsed with a heated liquid, especially water; (b) in a second stage, part of the organic substances in the material are decomposed under aerobic and/or anaerobic conditions; (c) the first-stage is applied during movement of the organic substance to the place at which the second stage is applied; (d) the rinsing liquid flows in the opposite direction to that (A) in which the organic material flows; (e) the organic residues (26) not freed in the first stage are decomposed under aerobic conditions; (f) the organic substances (22) freed into the water in the first stage are decomposed in the second stage under anaerobic conditions, and (g) the water is re-used after undissolved residues (26) have been removed; (h) the water is heated to 30-60 C. Also claimed is a suitable assembly with an inlet (8) for waste organic material and a conveyor (10) which transports wastes to the treatment station, during which wastes are exposed to hot water jets (18).    USE -   The process and assembly separate organic substances from animal and vegetable origin, e.g. catering wastes, and facilitate their decomposition under aerobic or anaerobic conditions as appropriate.    ADVANTAGE -   The efficiency of the composting process is enhanced in comparison with previous composting processes and assemblies.    (EP784039-B1)      In a waste composting process, the novelty is that: (a) in the first-stage, organic material is rinsed with a heated liquid, especially water; (b) in a second stage, part of the organic substances in the material are decomposed under aerobic and/or anaerobic conditions; (c) the first-stage is applied during movement of the organic substance to the place at which the second stage is applied; (d) the rinsing liquid flows in the opposite direction to that (A) in which the organic material flows; (e) the organic residues (26) not freed in the first stage are decomposed under aerobic conditions; (f) the organic substances (22) freed into the water in the first stage are decomposed in the second stage under anaerobic conditions, and (g) the water is re-used after undissolved residues (26) have been removed; (h) the water is heated to 30-60 C. Also claimed is a suitable assembly with an inlet (8) for waste organic material and a conveyor (10) which transports wastes to the treatment station, during which wastes are exposed to hot water jets (18).    USE -   The process and assembly separate organic substances from animal and vegetable origin, e.g. catering wastes, and facilitate their decomposition under aerobic or anaerobic conditions as appropriate.    ADVANTAGE -   The efficiency of the composting process is enhanced in comparison with previous composting processes and assemblies.