Study On Advanced Treatment Process Of Sewage Plant Effluent

Advanced treatment process in treating sewage plant effluent is studied and an appropriate treatment process is chosed to make sewage treatment plant effluent achieve the grade'A'standards of municipal wastewater treatment plant emission standards. Characteristics of pollutants are analysised by monitoring enfluent water quality in long-term.Operation parameters are determined and the process is evaluated by oprateing the pilot.The temperature, pH, DO and other relevant parameters are record.The characteristics and the parameters of process are studied. The affects of the temperature and hydraulic retention time on the removal rate of pollutants are analyzed. A matrix decomposition model of tow-stage biological contact oxidation treatment of secondary effluent is fitted.The experiment results show that it is difficult and need about 20-25days to film when temperature is about 9℃-18℃. pH value of effluent slightly lower than the influent.The pilot has some effects on the remove of the pollutants. Suspended solids, COD, ammonia nitrogen, TN, TP concentrations decreased from 5.09mg/L, 19.27mg/L, 0.26mg/L, 14.34mg/L, 0.47mg/L to 3.89mg/L, 13.80mg/L, 0.13mg/L, 9.89mg/L, 0.32mg/L respectively and the removal rates are 23.8%, 28.4%, 50.0%, 31.0%, 31.9%. The temperature effects on ammonia removal efficiency significantly. As the temperature up, the removal rate increased. When the temperature was 27.6℃, the ammonia nitrogen removal rate reached up to the highest, is about 84.5%. When hydraulic time comes to 2.5h from 1.5h, the removal rate on SS, COD, NH3-N, TN and TP removal rates are increased 6.25%, 6.67%, 5.04%, 6.18% and 6.00% respectively. The effect is not very obvious. The experiment also compared the contribution of two different stadges of biological contact oxidation on the purification secondary effluent. It notes that the second stadge on the removal of pollutants is limited and the removal contribution of of BCO is 2.5 times the first stadge. Finally, the paper summarized the mechanism of biological contact oxidation and obtained the matrix decomposition model.