Abstract: To ensure that with a method of aerobic decomposition of organic solids in which the solids to be composted are fed in the top of a compost tower and discharged from the bottom to be preferably re-used as a covering layer while a gaseous fluid containing oxygen is introduced into the compost tower, any odor nuissance is avoided, the fluid withdrawn from the compost tower after passing at least a part of the composing solids is returned to the decomposition tower independently on the pressure conditions prevailing in said decomposition tower, wherefrom additionally results a process course more advantageous in terms of energy.

Abstract: An apparatus for the aerobic decomposition of garbage, sludge, and similar organic waste materials having a reaction container (10) with vertically descending walls for the material to be decomposed, a discharge opening (12) extending over the entire cross section of the container (10), discharge elements (14) extending over the entire area of the discharge opening, and a removal device below the opening extending over the entire area of the discharge opening. A bi-directionally driven conveyor belt (16) transports the material to be removed from the discharge opening (12) into a first receptacle (22) which receives the material that has not been adequately purified or a second receptacle (24) for purified material. The conveyor belt (16) is preferably provided with cleansing devices (26).

Abstract: In order to obtain a more intense and quicker sewage purification and a better retaining of the activated sludge flocks in an activated sludge system with aeration tank and subsequently arranged secondary settler, the aeration tank is constructed as a sealed pressure reservoir (10) to which oxygenous gas can be supplied under pressure for dissolution in water, where the secondary settler is a flotation basin (24) and the pressure from the pressure reservoir (10) is available for flotation.