Abstract: In UASB-type biogas reactors, the biogas is separated from the rising waste water stream by collection hoods arranged in staggered fashion, in which a zero pressure level is maintained, at which the gas transition takes place. In cross-section shapes of existing collection hoods, the zero pressure surface is sharply reduced when the water level is high, and the conversion to gas is correspondingly sharply reduced. Therefore, in accordance with the invention, a rectangular section shape is employed in which the zero pressure surface remains unchanged. The topside of the collection hoods can be formed as a smooth sliding surface in the shape of a roof for the anaerobic sludge sediment.

Abstract: A method of thermal disposal of sewage sludge. The sludge is dried and incinerated. The flue gases from the incineration are washed. The flue gas dust resulting from the incineration and the sludge resulting from washing of the flue gases are treated together with high temperature combustion which includes melting of solids.