前置反硝化生物滤池深度脱氮效能与影响因素

前置反硝化生物滤池具有良好的脱氮性能，被广泛用于污水的深度处理。采用该工艺对城市污水处理厂尾水进行深度处理，通过调节硝化液回流比（50%、100%、150%）和水力负荷（1.0、1.5和2.0 m3·（m2·h）-1），考察前置反硝化生物滤池工艺对COD、TN、NH4+-N的去除效果。结果表明，当硝化液回流比为100%时，系统对污染物去除效果最好。在进水COD、TN、NH4+-N平均浓度为120、35和15 mg·L-1的水质条件下，出水COD、TN、NH4+-N平均浓度可降到7.62、5.02和0.60 mg·L-1，去除率分别为93.65%、85.65%和96.00%。在水力负荷为1.5 m3·（m2·h）-1条件下，系统对COD、TN和NH4+-N的平均去除率达到了83.00%、90.14%和95.73%，出水可以达到《城镇污水处理厂污染物排放标准》（GB 18918-2002）一级A标准。

Nitrogen removal efficiency and influencing factors in a pre-denitrification bio-filter system

Pre-denitrification bio-filter system is widely used in advance treatment of wastewater, owing to its excellent denitrification performance. A pre-denitrification bio-filter system was applied for treating laboratory simulated tail-water from municipal sewage treatment plant. By adjusting reflux ratio of nitrification liquor (50%, 100% and 150%) and hydraulic loading (1.0, 1.5 and 2.0 m3·(m2·h)-1), the removal efficiency of COD, TN and NH4+-N in the pre-denitrification bio-filter system were investigated. The results showed that, when the reflux ratio of nitrification liquor was 100%, the system had the best pollutants removal performance, the effluent concentrations of COD, TN and NH4+-N reduced from the 120, 35 and 15 mg·L-1 to 7.62, 5.02 and 0.60 mg·L-1, showing average removal efficiency of 93.65%, 85.65% and 96.00%, respectively. Under a hydraulic loading of 1.5 m3·(m2·h)-1, the average removal rates of COD, TN, NH4+-N reached to 83.00%, 90.14% and 95.73%, respectively, and the effluent water quality could meet the requirement of first grade A standards in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002).