水培蔬菜与潜流湿地组合工艺净化农村生活污水尾水

Tail Water purification of Rural Sewage by Combined Processes of Hydroponic Vegetables and Subsurface Flow Wetland

构建水培蔬菜、潜流湿地、水培蔬菜+潜流湿地、潜流湿地+水培蔬菜4种工艺系统,净化经过脉冲生物滤池处理后的农村生活污水,考察水力负荷对各系统中污染物去除效能的影响,以及各工艺中污染物的沿程变化规律,分析了氮磷资源化利用的效率,并评估了水培蔬菜产出空心菜的安全性。结果表明:在工艺进水CODCr、TN、TP、NH+4-N和NOx-N平均浓度分别为66.4、14.9、1.1、4.6 mg/L和10.9 mg/L,水力负荷为0.1~0.3 m3/(m2·d)时,水培蔬菜、潜流湿地、水培蔬菜+潜流湿地系统适宜水力负荷分别为0.2、0.3、0.3 m3/(m2·d),此时各系统不仅氮、磷去除负荷达到最大,同时出水能够满足一级A标准;水培蔬菜、潜流湿地工艺系统内CODCr、TN及TP的浓度在前1/4段去除较多,后段近似呈线性下降,水培蔬菜+潜流湿地组合系统内,前段水培蔬菜对CODCr、TN及TP去除的贡献率较高,分别达到40.7%、58.1%、53.7%,采收的空心菜重金属含量未超标。采用水培蔬菜与潜流湿地组合工艺处理农村生活污水尾水,在确保出水水质达标的同时,可实现污水中氮磷的有效利用。

Four kinds of systems to purify tail water in rural were constructed:hydroponic vegetables system,undercurrent artificial wetland,combination system of undercurrent artificial wetland/hydroponic vegetables and hydroponic vegetables/undercurrent artificial wetland.The effect of hydraulic load on pollutants removal efficiency and variation rule of pollutant concentration along the system were researched.The utilization efficiency of nitrogen and phosphorus resource was analyzed,and the safety of water convolvulus was assessed.Results showed that average concentration of CODCr,TN,TP,NH+4-N,NOx-N in tail water were 66.4,14.9,1.1,4.6,10.9 mg/L,hydraulic load was 0.1~0.3 m3/(m2·d).To maximize the resource of nitrogen and phosphorus and ensure the effluent reach the first A level of GB 18918—2002,the proper hydraulic load for hydroponic vegetables system and hydroponic vegetables/undercurrent artificial wetland were 0.2,0.3,0.3 m3/(m2·d).In hydroponic vegetables system and undercurrent artificial wetland system,concentration of CODCr,TN and TP decreased more in the former quarter.In hydroponic vegetables/undercurrent artificial wetland system,removal rate in former hydroponic vegetables contributed up to 40.7%,58.1%,53.7%for CODCr,TN and TP.The contents of heavy metal in the spinach were not overweight according to the standard.Hydroponic vegetables and combination of undercurrent artificial wetland were suitable treatment of rural tail water to ensure the effluent quality and effective use of nitrogen and phosphorus in sewage.