Disposal of sewage sludge

摘要

A process for disposing of sanitary sewage sludge by producing a pumpable slurry of sewage sludge and solid carbonaceous fuel e.g. coal, petroleum coke, rubber. The slurry is burned as a fuel in a partial oxidation gas generator, furnace, or boiler. In the process, an aqueous slurry of sewage sludge is concentrated by removing water by means of a belt filter press or presses. The dewatered slurry of sewage sludge, with or without low grade solid carbonaceous fuel mixed therewith, is hydrothermally treated and cooled and depressurized. The viscosity of the slurry of sewage sludge with or without low grade solid carbonaceous fuel is reduced to less than about 2000 centipoise by shearing. Sheared sewage sludge without low grade solid carbonaceous fuel is then ground together with a solid carbonaceous fuel. The pumpable slurry so produced, is burned with a free-oxygen containing gas in a partial oxidation gasifier, furnace, boiler, or incinerator to produce a hot raw effluent gas stream. In a preferred embodiment, the effluent gas stream is cleaned and purified and non-contaminating ash and slag are separated. By this process, noxious sewage sludge may be disposed of without contaminating the environment. By-product synthesis gas, reducing gas, or fuel gas may be produced.