中文摘要：

提出了一种分段式A2／O工艺，是在普通A2／O工艺的各单元段增加泥水分离器，使不同处理单元富集不同的功能菌群，以提高系统的脱氮除磷效率。通过工艺运行优化和对比试验表明，分段式A2／O工艺的最佳污泥回流比和内回流比分别为100％和200％，并且该工艺的抗冲击负荷能力较强；分段式A2／O工艺对COD、TN、NH3-N和TP的平均去除率分别为84％、62％、69％和88％，明显优于普通A2／O工艺（去除率分别为72％、51％、55％和75％）。

英文摘要：

A new nitrogen and phosphorus removal process called staged A2/O process was pro- posed, which actually was adding a solid-liquid separator in each unit of the conventional A2/O process. The staged A2/O process enriched different functional microorganisms in different treatment units, which could improve the nitrogen and phosphorus removal efficiency. The process optimization and comparative tests showed that the optimal sludge reflux ratio and internal reflux ratio of the staged A2/O process were 100% and 200%, respectively, and the process had high resistance to shock loading. The average re- moval rates of COD, TN, NH3 - N and TP in the staged A2/O process were 84%, 62%, 69% and 88%, respectively. The treatment efficiency of the staged A2/O process was higher than that of the con- ventional A2/O process with the average removal rates of 72%, 51%, 55% and 75%, respectively.