多级垂直流人工湿地对北方农村生活污水的处理分析

Analysis of Northern Village Sewages Treatment by Multi-stage Vertical Flow Constructed Wetland

文章采用多级垂直流人工湿地处理北方农村生活污水,考察了稳定运行期水力负荷、植物收割以及季节对COD、NH4^+-N、TN和TP的去除影响。结果表明:COD、TN和TP去除随水力负荷增加呈递减趋势,在0.15 m^3/(m^2·d)时去除最佳,出水浓度分别为18~30、9~25和0.4~0.5 mg/L。NH4^+-N去除随水力负荷增加呈先增后减趋势,在0.25 m^3/(m^2·d)时去除率最佳,出水浓度为0~6 mg/L。在水力负荷为0.15 m^3/(m^2·d)时,植物收割后COD、NH4^+-N、TN和TP的去除均有所降低。不同季节时,夏季湿地处理效果最佳,冬季最差。同时对比实验表明,夏季水力负荷为0.15 m^3/(m^2·d)时,多级垂直流人工湿地对COD、NH4^+-N、TN和TP的去除效果优于单级水平流人工湿地,其出水达到城镇污水处理厂污染物排放一级A标准。

Multi-stage vertical flow constructed wetland(MVCW)was applied to treat northern village sewages in this work.It was investigated that the effect of hydraulic loading,plant harvest and season on the COD,NH4^+-N,TN and TP removal in the smooth phase.The results showed that the removal of COD,TN and TP decreased with the hydraulic loading increase.The optimal condition was hydraulic loading of 0.15 m^3·(m^2·d)^-1.The concentration of COD,TN and TP in effluent was 18~30,9~25 and 0.4~0.5 mg/L,respectively.The removal of NH4^+-N firstly increased and then decreased with the increase of hydraulic loading.the optimal condition was 0.25 m^3·(m^2·d)^-1.The concentration of NH4^+-N in effluent was 0~6 mg/L.After the plant harvest,the removal of COD,NH4^+-N,TN and TP decreased than those previously.Additionally,the MVCW treatment effect was the best in summer which the worst in winter.Meanwhile,under the hydraulic loading of 0.15 m^3·(m^2·d)^-1 in summer, the removal rate of COD, NH4^+-N, TN and TP was better in MVCW than in single-stage horizontal flow constructed wetland, and the effluent could reach the level A discharge standard.