Method and arrangement for treatment of sewage sludge

Abstract

In a treatment or processing or sewage sludge in the sense of recycling, where the sewage sludge is to begin with dried (T), subsequently converted (K) under anaerobic conditions at approximately 250.degree. to 350.degree. C. and finally is sintered at at least 1250.degree. C. in successive steps, it is proposed to perform all process steps including the conveyance of the commodity to be processed between the individual processing steps successively in continuous passage in a closed system. Only the vapors are removed in this system in the drying stage (T) and the conversion gases in the conversion stage (K) and they are condensed; the heat quantity contained in the flue gas generated during the sintering process (S) is utilized for heating to begin with the conversion stage (K) and after that the drying stage (T). Because the flue gases are used for heating the processing steps in the sequence of the naturally occurring temperature gradient, the processing of the sewage sludge is achieved so as to be nearly self-sufficient as far as the energy requirement is concerned, meaning the energy required for the processing is largely supplied by the calorific value of the organic ingredients contained in the sewage sludge itself. Because the sewage sludge is processed in a closed system, nefarious effects upon the environment are avoided.

Dependencies are inferred from the claim text.