中文摘要：

以西安市第五污水处理厂改良型A^2／O工艺的实际运行监测数据为依据，分析了该工艺对城市污水中主要污染物的去除效果。结果表明：改良型A^2／O工艺对COD、BOD5、TN、TP、NH^＋4-N和SS的去除率分别达到95．6％、97．1％、74．6％、89．8％、97．5％和98．0％以上，且工艺运行稳定，具有较强的抗冲击负荷能力和稳定的出水水质。同时，分析了实际运行中总磷去除率不稳定的原因，提出了污水处理厂在今后运行中应及时调整工艺运行工况，合理控制回流污泥中NO^-3-N浓度和好氧区DO浓度，这不仅能确保污染物的去除效率，而且可降低运行能耗，实现节能减排。

英文摘要：

On the basis of the monitoring data of the modified A^2/O process in the Fifth WWTP in Xi＇ an City, the removal efficiency of main pollutants in municipal wastewater by the modified A^2/O process was analyzed. The results showed that the removal rates of COD, BOD5, TN, TP, NH^＋4 - N and SS could reach 95.6% , 97.1% , 74.6% , 89.8% , 97.5% and 98.0% or above, respectively. This process had strong resistance to shock loading and stable effluent quality. The reasons for unstable TP re- moval efficiency were analyzed. The future operation of the WWTP and the process conditions should be timely adjusted, and the NO^-3- N concentration in the return sludge and the DO concentration in the aer- obic zone should be reasonably controlled, which could achieve high removal efficiency of pollutants and reduce power consumption, finally achieving energy-saving and emission reduction.