Optimization Of A~2/O Process In 1st Wastewater Treatment Plant In Panjin

In recent years, although effects have putted on water resource protection and water waste controlling, water pollution and water environment deterioration are still continuing. Meanwhile, water eutrophication also became more serious. These deteriorated water environment and ecological system, and also made negative influences on human health and residency. A2/O process is one of most important processes to remove phosphorus and nitrogen, and it is of high efficiency, high stability, low cost and easy manipulation. PanJin First sewage plant is in charge of the treatment of the main-part civil sewage. It is now applying the A2/O process and plays an important role in maintaining the ecological environment. However, the continuing urbanisation and industrialization raised several problems in sewage treatment. Therefore, it is necessary and urgent to solve these problem by optimizing the sewage treatment process.In this paper, the treatment of wastewater treatment plant with A2/O process, inverted A2/O process and pre anoxic A2/O process are discussed. The results show that in the same operating condition, the removal of TN is better than A2/O, and the removal efficiency of TN is better than 100%when the sludge return ratio is 50%. At the same time, the A2/O process is more easily influenced by the change of sludge return ratio, and the change of A2/O process system has little effect on the change of sludge return flow in TN. In the removal of TP. A2/O process system is a better treatment effect than the inverted A2/O process system. Considering the practical effect of simultaneous nitrogen and phosphorus removal and the economic efficiency of the treatment process, the 100% sludge reflux ratio, the ratio of 200%mixed liquor, and the sludge concentration of 3000mg/L are the most suitable for A2/O process and A2/O process. In addition, the A2/O process and A2/O process for the removal of organic matter are good, the TN removal efficiency of A2/O process system is better, the removal rate is 74% higher than that of A2/O process system. The removal efficiency of TP is better than that of A2/O, and the removal rate is about 90%. By changing the water inlet mode of the pre-anoxic A2/O process, a better effect of simultaneous removal of nitrogen and phosphorus can be obtained.In conclusion, this study provided the experience for the high-level removal of phosphorus and nitrogen in civil sewage and the basis for the researches on quantity control and energy saving of pre-anoxic A2/O process.