Study On Enhance Biological Phosphorus Removal And Stable Running Technology Of Kunshan City North Sewage Treatment Plant A~2/o Process

With the national and local effluent discharge standards to be more stringent, the Taihu Lake region and other key areas increase of the sewage discharge standards accordingly, and many municipal wastewater treatment plants are required to transform processes to meet the requirements of discharge standards. Kunshan City, North District Wastewater Treatment Plant uses a modified version of A-A²/O process, there are some problems of instability, total nitrogen of the effluent is too high and so on. Through this research projects, First, analyzed the wastewater treatment plant three years daily monitoring data from January 1, 2006 to December 31, 2008, include operation stability, the sewage biochemical analysis, the influence of temperature, the impact of C/N ratio and C/P ratio, and the effects of assimilation from the five aspects of the overall macro-analysis. Second, from July 2009 to August 2009, monitored and analysied 8-time All-flow Sampling for the main technology of the A-A²/O in 7days. Third, from December 2009 to January 2010, conducted 11 trials of biological phosphorus removal kinetics. Attained the following main conclusions:1. At present the compliance rate of accumulation of the major water is not high; the influent is inadequate or in overloaded operation in more than half of the time; the removal of nitogen for the system is unstable; well the removal of TP is stable relatively. The load of COD, NH3-N, TN and TP does not exceed the capacity of the system,there is spare capacity. The most appropriate volume load is 0.7¹.3KgCOD/m³.d, and the removal rate is around 90% .2. Except of NH3-N ,The operation results of wastewater treatment plant in summer better than it in winter, increase the load of TP will raise the risk for water degradagion.3. With the increase of C/N ratio, TN removal rate will became lower. C/N ratio had no apparent restrictions on the removal of TP.4. The volume loading of TN is between 0.06 and 0.12 TN/m³.d. The volume loading of TP is between 0.001 and 0.012 TP/m³.d. The front half of the first corridor of oxidization tank changed for anoxic zone did not play denitrification.The denitrification need to be strengthen.5. The system assimilation of nitrogen and phosphorus removal can not be ignored, and assimilation of nitrogen and phosphorus accounted for an average of the influent of TN and TP were 12.46% and 34.22%.6. respectively, established biological phosphorus removal kinetics in the anaerobic tank, anoxic tank, the front two corridors of aerobic tank and the third corridor of aerobic tank. And calculated the organic matter metabolic rate of all tanks and established anaerobic metabolism of organic matter kinetic.7, In the dynamic trial period, PAOs were instability in anaerobic phosphorus release. the mean of aerobic phosphorus uptake rate was 0.0055mgPO₄^3--P/(gVSS.h), the mean anoxic phosphorus uptake rate of 0.0036mgPO₄^3--P/(gVSS.h), DPB account for only a small part of denitrifying bacteria in anoxic zone. Biological phosphorus removal ineffective, mainly because wasterwater may contain heavy metals ions such as Cu²⁺, the number of PAOs reduced and activity decreased.All the conclusions has important theoretical and practical significance for the stable operation of wastewater treatment plant.