多级潮汐流人工湿地对城市污水处理厂生产废水中典型污物的去除特征

Characteristics of Typical Pollutants Removal From Reject Water of Municipal Wastewater Treatment Plant Using a Multi-Stage Tidal Flow Constructed Wetland

采用多级潮汐流人工湿地处理城市污水处理厂生产废水(NH_4^+-N的质量浓度平均为817.6 mg/L),以豆石、砾石和建筑废砖作为人工湿地填料,平均水力负荷为0.618 m^3/(m^2·d)条件下,研究其对污染物的去除特征。结果表明,在系统运行阶段,进水NH_4^+-N、TN、PO_4^(3-)-P的质量浓度及COD的平均分别为817.6、819.0、17.86 mg/L及379.46mg/L,出水NH_4^+-N、TN、PO_4^(3-)-P的质量浓度及COD的平均分别为11.46、316.4、8.81 mg/L及43.99 mg/L,平均去除率分别为97.88%、61.37%、49.32%及88.41%;平均硝化速率为(20.79±2.26)g/(m^2·d),硝化进程良好;平均反硝化速率为(13.09±2.58)g/(m^3·d),出水中TN主要为NO_3^--N(平均质量浓度为277.3 mg/L)。尽管平均反硝化速率较高,但为进一步降低生产废水回流所引起的TN的循环累积量,需进一步强化反硝化进程。

The multi-stage tidal flow constructed wetlands （MTF-CWs） that used pisolite, gravel and construction waste brick as the substance was employed for reject water treatment of municipal wastewater treatment plant （the mass concentration of NH4^＋-N is 817.6 mg/L）. The average hydraulic load rate of MTF-CWs was 0.618 m^3/（m^2· d）, Characteristics of contaminants removal of MTF-CWs on reject water was investigated. The results showed that, when the average influent mass concentrations o fNH4^＋-N, TN, PO4^3--P and COD in the operation period were 817.6, 819.0, 17.86 and 379.46 mg/L, the average effluent mass concentrations of NH4^＋-N, TN, PO4^3--P and COD in the operation period were 11.46, 316.4, 8.81 mg/L and 43.99 mg/L, respectively. The average removal efficiency was 97.88%, 61.37%, 49.32% and 88.41%, respectively. The nitrification rate and the denitfification rate of MTF-CWs were （20.79±2.26） and （13.09±2.58） g/（m^3·d）, respectively. The average effluent mass concentration of NO3-N was 277.3 mg/L. It is necessary to reduce TN feedback through reject water recycling in a municipal wastewater treatment plant.