PROCESS FOR THE WORKING-UP OF SLURRIES CONTAINING ORGANIC IMPURITIES FORMED AS BY-PRODUCTS IN THE PURIFICATION OF SEWAGE

摘要

A process for the utilization of anaerobic digested sewage sludge which comprises: (a) heating the digested sewage sludge to at least 80 DEG C and then optionally cooling it from 80 to 40 DEG C; (b) separating the heat treated digested sewage sludge, optionally in the presence of a coagulant, to give a concentrate and a supernatant; (c) preparing a culture medium by adding to the supernatant a C1-C3 alcohol and a nitrogen-containing inorganic salt and, optionally, one or more water-soluble vitamin precursors or growth factors; (d) inoculating the culture medium with anaerobic digested sewage sludge; (e) anaerobically fermenting the inoculated culture medium at from 26 to 38 DEG C; (f) separating the biomass from the fermentation liquid formed during the fermentation. e