초록 ▼

This invention relates to an improved process for the treatment of municipal waste and particularly to the reduction of organic sludges generated in the biological digestion of organic material. In the conventional processes the waste containing organic matter is contacted with an oxygen-containing

This invention relates to an improved process for the treatment of municipal waste and particularly to the reduction of organic sludges generated in the biological digestion of organic material. In the conventional processes the waste containing organic matter is contacted with an oxygen-containing gas in the presence of biologically active organisms under conditions to produce biomass which, on separation, forms a sludge. A portion of the sludge often is returned to the aerobic digestion process. This invention relates to an improvement for sludge reduction in these processes wherein a portion of the sludge is hydrolyzed and then subjected to biological digestion in an autothermal aerobic digestion zone. The effluent from the autothermal aerobic digestion zone usually is returned to the initial aerobic digestion process or submitted for disposal. In another embodiment of the invention, the hydrolyzed sludge is charged to an autothermal anaerobic digestion process wherein a substantial portion of the organic matter is converted into methane and the effluent from the autothermal anaerobic digestion process subsequently charged to the autothermal aerobic digestion process for effecting final reduction of organic matter. By these combinations one can generate a preselected value of sludge and, in some cases, one can operate under conditions such that there is no net generation of sludge.

대표청구항 ▼

In an activated sludge process wherein waste containing organic matter is contacted in an aerobic zone with an oxygen-containing gas in the presence of suspended biologically active organisms under conditions for effecting biological digestion of said organic matter and generating an effluent contai

In an activated sludge process wherein waste containing organic matter is contacted in an aerobic zone with an oxygen-containing gas in the presence of suspended biologically active organisms under conditions for effecting biological digestion of said organic matter and generating an effluent containing suspended organic matter, said effluent being separated into a disposable aqueous fraction and a heavy sludge fraction containing organic solids, with a portion of the sludge being recycled to said aerobic zone, the improvement for enhancing sludge reduction in said activated sludge process which comprises the steps: (a) hydrolyzing at least a portion of said heavy sludge fraction under conditions for solubilizing at least a portion of said organic solids therein and thereby forming a hydrolyzed sludge containing solubilized organics; (b) charging said hydrolyzed sludge to an autothermal thermophilic aerobic digester zone wherein the hydrolyzed sludge is contacted with an oxygen-containing gas at a temperature ranging from 35°-75°C. for digesting and effecting decay of said solubilized organics and generating an effluent stream; (c) removing said effluent stream from said autothermal thermophilic aerobic digester zone.