污水处理厂二级出水深床滤池超深度脱氮研究

采用深床滤池处理污水厂二级出水，以使出水 TN 提升至地表 Ⅳ 类水水质。在中试系统进水 TN 和 NH 4 +_ N 的平均值为 13.88 和 0.68 mg/L 、碳源 (99% 的乙酸 ) 投加量为 60 mg/L 条件下，当空床水力停留时间分别为 15 和 30 min 时，出水 TN 的平均值分别为 0.81 、 0.74 mg/L ， TN 平均去除率分别为 94.16% 、 94.67% ，反硝化滤池的平均容积负荷为 0.64~1.28 kg NO 3 - -N/(m 3 ·d) 。当进水 TN 和 NH 4 +_ N 的平均值分别升高至 18.05 和 1.40 mg/L 、碳源投加量为 40 mg/L 时，同样运行条件下出水 TN 的平均值分别为 5.04 和 2.36 mg/L ，去除率分别为 72.08% 和 86.93% 。中试结果表明，控制二级出水 TN 和 NH 4 +_ N 分别在 15 和 0.5 mg/L 以内、空床水力停留时间为 30 min 、碳源投加量（ C/N=4.5 ）足够时，深床滤池反硝化脱氮系统能稳定保证出水 TN 达到在地表 Ⅳ 类水水质标准

The secondary effluent from a wastewater treatment plant was treated by a deep bed filter, so as to improve TN in the effluent to the surface water class Ⅳ criteria. When the average TN and NH4^+-N concentrations in the influent of the pilot-scale system were 13.88 mg/L and 0.68 mg/L, dosage of the carbon source (99% acetic acid) was 60 mg/L and empty bed hydraulic retention time was 15 min and 30 min, the average TN concentrations in the effluent were 0.81 mg/L and 0.74 mg/L, the corresponding average removal efficiencies were 94.16% and 94.67%, respectively , and the average volumetric loading rate was 0.64-1.28 kgNO3^--N/(m³·d). When the average TN and NH4^+-N concentrations in the influent increased to 18.05 mg/L and 1.40 mg/L, and the dosage of carbon source was 40 mg/L, the average TN concentrations in the effluent and the removal efficiencies were 5.04 mg/L and 2.36 mg/L and 72.08% and 86.93% under the same operational conditions. When TN and NH4⁺-N in the secondary effluent were controlled to be less than 15 mg/L and 0.5 mg/L, empty bed hydraulic retention time was 30 min and dosage of the carbon source (C/N=4.5) was sufficient in the pilot-scale system, TN in the effluent of the deep bed filter denitrification system could always meet the surface water class IV criteria.