The Research On The Uncoupled Metabolism Model Of Excess Sludge Reduction And OSA (Oxic-settling-anoxic) Process

The activated sludge process is commonly used for the treatment of Wastewater, which also generates a large quantity of excess sludge daily as a byproduct. There are various kinds of technology developed to reduce excess sludge, among which, the use of chemical uncouplers are very prospective because it is easy to run and no extra treatment facilities are needed. Oxic-settling-anoxic(OSA) process may not be effective as the control of excess sludge production by chemical uncouplers. The OSA process can improve the settleability of sludge, and it needs no modification on the conventional activated sludge and less running cost. This paper emphasized the research on the uncoupled metabolism model of excess sludge reduction and OSA process on the review of the technical and the theory of sludge reduction of past and present.In the research of uncoupled metabolism model of excess sludge reduction, ortho-chlorophenol(OCP),2,4-dichlorophenol(DCP), 3,3',4',5-tetrachlorosalicylanilide(TCS), para-dinitrophenol(PNP) and 2,4-dinitrophenol(DNP) were chosen for short-term tests of their ability to reduce sludge yield by a bottle shaking test. The most effective chemicals, DNP, PNP and TCS were tested for various uncoupler concentrations and biomass concentrations. TCS was then tested in a lab-scale completely mixed activated sludge batch culture. The model was verified with experimental data in a completely mixed activated sludge batch test, but the results from the bottle shaking batch test are inconsistent. The observed growth yield(Y_obs) is decreased with the increase of the ratio of initial uncoupler concentration to initial biomass concentration(C_u/X_o). The real strength of chemical uncoupler imposing on biomass...