潜流人工湿地在城市污水三级处理中的应用

Application of subsurface flow constructed wetland in tertiary treatment of urban wastewater

采用页岩/钢渣强化潜流人工湿地作为城市污水处理厂三级处理工艺。结果表明:在平均水力负荷为0.32m·d-1的条件下,当进水有机物(CODcr)、总氮(TN)、总磷(TP)平均浓度为33.9、15.1和1.57mg.L-1时,出水CODcr平均浓度为13.6mg.L-1,去除率为60%,面积速率常数KA值为0.3m·d-1,温度对CODcr的去除影响不明显;出水TN浓度在5.4～14.3mg.L-1之间波动,KA值为0.09～0.31m·d-1,去除率受温度的影响较大,随着进水硝态氮比例的提高和运行时间的延长,湿地对TN的去除效率有上升趋势;稳定阶段出水TP浓度为0.6mg.L-1,去除率为50%,KA为0.26m·d-1,温度对TP去除影响不大。

A pilot scale shale/slag-filled subsurface flow constructed wetland was used in the tertiary treatment of urban wastewater. The results showed that under the condition of average hydraulic loading rate being 0. 32 m · d^- 1 and when the average concentrations of CODer, TN and TP in the influent were 33.9, 15. 1 and 1.57 mg · L^-1 , respectively, the average concentration of CODer in the effluent was 13. 6 mg · L^-1 , its removal rate was 60%, and the first-order areal rate constant KA was 0. 3 m · d^- 1 The removal of CODCr, was less affected by temperature. The TN concentration in the effluent fluctuated from 5.4 to 14. 3 mg · L^-1 , KA fluctuated from 0.09 to 0. 31 m · d ^-1, and the N removal was negatively affected by lower temperature while positively affected by higher NOx-N/TN ratio and longer operation time. At steady stage, the average concentration of TP in the effluent was 0. 6 mg · L^-1 , its removal rate was 50%, and KA was 0. 26 m · d^-1. Temperature had less effect on TP removal.