COMPOSTING SYSTEM FOR SEWAGE SLUDGE USING BY AUTOTHERMAL THERMOPHILIC AEROBIC DIGESTION

摘要

A system for producing compost from sewage sludge is provided to stabilize sludge at a high temperature while avoiding a need for a separate external energy source, and to obtain high-quality compost free from germs and parasite eggs. A system for producing compost from sewage sludge comprises: a first concentration tank(1) for concentrating first sludge containing particles; a mechanical concentration unit(2) for concentrating second sludge generated by biological treatment of organic materials; a first heat exchanger(3) for mixing the sludge obtained from the preceding steps: a first autothermal thermophilic aerobic digestion(ATAD) tank(4) for treating the sludge at 35-45 deg.C for 3-4 days; a second ATAD tank(5) for treating the sludge at 50-60 deg.C for 3-4 days; a wet scrubber(11) for treating at least 80% of ammonia gas generated upon the decomposition of the organic materials; an electro-oxidation tank(12) for converting at least 90% of aqueous ammonia into N2 gas; a second heat exchanger(10) for generating hot water from the hot (60 deg.C) sludge; a sludge storage tank(13) for storing the sludge subjected to heat transfer via heat exchange in the first heat exchanger; and a water removing unit(14) for agglomerating the sludge with a polymer agglomerating agent. In the system, the ATAD tanks generate reaction heat, stabilize the sludge to a stable material causing no redecomposition of the treated sludge, removes germs and parasite eggs contained in the sludge to a degree of at least 99%, and includes an automatic suction circulated aeration unit(6), an automatic suction spiral aeration unit(7) and a debubbling unit(8).