中文摘要：

以西安市某污水处理厂改良AAO工艺为研究对象,分析了该工艺实际运行中除磷效果不稳定、出水TP含量难以达到GB 18918-2002一级A标准排放的影响因素。结果表明,生化处理系统厌氧区环境差、污泥龄较长、污泥膨胀、回流污泥中硝态氮和磷含量较高等是主要原因。针对实验结果提出了降低外回流比、增大内回流比,降低污泥龄,合理调节曝气量等工艺运行参数的改进措施。

英文摘要：

The improved AAO process in some Xi＇an Fifth Wastewater Treatment Plant was taken as the research object, and main factors of instability of phosphorus removal and the effluent difficult to reach discharge standards were analyzed. The results showed that the factors including the poor environment of anaerobic period, longer sludge age, sludge bulking, return sludge water with high NO3-N and PO43-P content, and others were main Reasons responsible for the poor quality of produced water. Meanwhile, the improvement measures was put forward according to the experimental results, such as reducing the external reflux ratio, increasing internal reflux ratio, reducing the sludge age, adjusting the aeration process and selecting process parameters reasonably.