Studies On Reducing Sludge Yield By Using Auncoupler In The Activated Sludge Process

Up to now, for wastewate treatment, especially municipal wastewater biological treatment, activated sludge process is the most feasible method which used extensively worldwide. However, routine activated sludge process always produce large amount of sludge which needs further treatment and disposal. Therefore, how to reduce the excess sludge during the wastewater treatment process is very important. There are various kinds of technology developed to reduce excess sludge, among them, using chemical uncouplers are very prospective, as it is easy to run and no extra treatment facilities are needed.This paper has studied the effect on sludge biomass production of addition of uncoupler TCP (2,4,5-Trichlorophenol). Eight batch reactors filled with activated sludge were operated in a batch mode in parallel. Batch experiments were carried out for 4 hours. The increasing sludge concentration and COD removal efficiencies were obviously reduced at concentrations of TCP ranging between 2.0¹0.0mg/L, and were not changed much at concentrations of TCP ranging between 10.0²0.0mg/L; The growth yield is reduced by 64% from 0.498 to 0.154. In this study the model forgrowth yield at the presence of uncoupler and its conventional S₀ /X₀ conditions was validated by experimental data that was adapted to high S₀/X₀ condions. Y_obs is the function of C_u/X₀. Y_obs reduced with C_u /X₀ increasing; The energyuncoupling coefficient (E_u) reduced with C_u / X₀ increasing.Three batch experiments were carried out for 30 days. The concentration of TCP was 0, 5.0, 10.0mg/L. The biomass growth was reduced with increasing concentration of TCP; After addition of TCP, the concentrateons of nitrogen and phosphorus are affected at different degrees; The sludge settling properties was almost not affected by the presence of TCP during the 30 days of operation in this study. Such a sludge growth is associated with the microbial activity increasing in terms of the inhancement of SOUR. Meanwhile it was abserved that filamentous bacteria still grew in the control reacter after 30days operation.