中文摘要：

针对武汉市沙湖污水处理厂A^2／O工艺在低温条件下脱氮效果不佳的问题，分析其原因并做出相应调整，提出了优化方案。在冬季低温时通过将污泥浓度提高到3500mg／L、内回流比上调为180％、曝气池DO提高至4．5～5．5mg／L等措施，可强化A^2／O工艺在低温条件下的脱氮效率，平均出水NH3-N、TN浓度分别为4．9、12．5mg／L，出水水质优于《城镇污水处理厂污染物排放标准》（GB18918-2002）的一级B标准。

英文摘要：

The reasons for low nitrogen removal efficiency of the A^2/O process at low temperature in Shahu WWTP were analyzed, the corresponding adjustments were made, and the optimized scheme was proposed. At low temperature in winter, the nitrogen removal efficiency of the A^2/O process could be improved by increasing the sludge concentration to 3 500 mg/L, the reflux ratio to 180% and the DO in the aeration tank to 4.5 - 5.5 mg/L. The average effluent concentrations of NH3 - N and TN were 4.9 mg/L and 12.5 mg/L respectively. The effluent quality was superior to the first level B criteria specified in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant （GB 18918 -2002）.