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With economic development and people’s living standards, the voice of protecting and improving the environment is also getting higher and higher. Water is the main component of human being’s living environment, so constructing urban sewage treatment plants reasonably is an essential requirement for urban development.At present, most wastewater treatment plants are using activated sludge to treat the domestic sewage. It is of great significance for various activated sludge process research and development of new techniques, for improving the status of municipal wastewater treatment, for improving the pollutant removal efficiency and greater energy-saving emission reduction.Orbal oxidation ditch process has been widely used in treating the sewage of urban life. The good effect of organic matter, nitrogen and phosphorus removal has been generally recognized. Based on the Orbal Oxidation Ditch process commissioning study on wastewater treatment plant in Yushe county, the author gives further analysis of the removal mechanism of organic matter, nitrogen and phosphorus. In actual process of commissioning, there are many changes in response to various conditions, a profound analysis of the effect of Oxidation Ditch Orbal factors is present in the thesis. It studies the relationship between temperature, CDO and nitrogen, phosphorus removal and finally the best operating conditions of Orbal Oxidation Ditch is put forward theoretically, which has a certain guiding sense.The wastewater treatment plant in Yushe county was built in 2004, but it has not been run until in November 2008. Because the actual inflow is far below the design scale, which resulting in the continued deterioration of the environment and a serious waste of resources. Therefore, before the commissioning starts, we proposed the process transformation plan and part implementation in view of the actual situation in Yushe County wastewater treatment plant, which created the advantage for the follow-up commissioning. The commissioning started from November in 2008, first carried out the cultivation of activated sludge acclimation. Raise initial period, because of water shortage, high aeration, the plate spinning drift effect difference, low temperature etc., sludge grew slowly even died massively, and the sludge target (MLSS, SV30, SVI) was extremely low, the first stage sludge raise announced defeat. Subsequently, in the absorption defeat lesson’s foundation, based on careful analysis of the reasons for failure, in the second period, we improved the adverse conditions for the growth of sludge, the sludge quantity grew with stability, and SV30, SVI also gradually improved, sludge cultivation obtained success. In this process, we summed up a lot of practical experience, which provided practical and feasible reference for sludge cultivation under such harsh conditions.With the successful cultivation of activated sludge, we started a careful study on removal efficiency of Orbal Oxidation Ditch’s organic matter, nitrification and denitrification, phosphorus removal etc. under different conditions. The results show that the oxidation ditch process Orbal in low-load state still has a higher removal rate and good effect of phosphorus removal. CODcr, BOD5, TP removal rates were 84.9%、93.5%、86.3%. While the effect of NH3-N removal was less effective, further studies have found that the too low water temperature mainly due to nitrification and denitrification at the same time so difficult to track. In the spring of year 2009, we carried on several day-long examination continuously to Yushe County wastewater treatment plant, the NH3-N average removal rate reached77.3%, this result indicated that the oxidation ditch Orbal has good denitrogenation effect under appropriate temperature conditions.Since the commissioning in Yushe County Wastewater Treatment Plant in November, the temperature continued to reduce and later it was winter. How to ensure the smooth water plant over the winter and the processing effect smoothlyhas become an important issue of commissioning. By comparing the running process indicators in different temperatures, detailed analysis of specific issues and thinking, we summed up the process at low temperature operation law, in addition to the effluent NH3-N outside the remaining indicators low temperatures were able to meet emission standards by adjusting the amount of aeration, reflux ratio and so on .At the end of the work of commissioning, the author makes a systematic summary over the past few months and carries out a detailed economic, environmental and social analysis, finally gives some reasonable suggestions for the better operation of wastewater treatment plant.
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