生态滤沟对城市路面径流的净化效果

Purification Effects of Biological Filter on Urban Road Runoff

随着城市化进程的加快,城市路面径流污染问题日益严重,运用工程措施对其实施控制具有重要意义。在西安理工大学露天试验场设计和建设了6条不同配置方式的生态滤沟,通过试验分析生态滤沟对城市路面径流中污染物的净化效果及其影响因素。结果表明:在所选的基质中粉煤灰的净化效果较好,其对铵氮、总氮、可溶性正磷酸盐、总磷的去除率可分别达到30%～45%,25%～30%,90%～95%,60%～90%;较无植被情况,在有植被条件下生态滤沟对总氮的去除率可提高5%～30%,而对磷的净化效果相差不大;随着入流水力负荷的增大,生态滤沟对污染物的去除率会降低,铵氮和总氮的去除率在高水力负荷和低水力负荷时相差10%左右,可溶解性正磷酸盐和总磷的去除率在高负荷和低负荷时相差可达30%左右;随着进水污染物浓度的增大,COD、可溶解性正磷酸盐、总磷的去除率呈现先增大后减小趋势,铵氮去除率呈现增大趋势,总氮去除率呈现先减小后增大的趋势。随着入流时间的延续,生态滤沟对入流流量、入流水量、入流污染负荷的削减能力减弱。

With the acceleration of urbanization, urban road runoff pollution is increasingly serious. It has im- portant significance to control il applying engineering measures. Six biological filters with different mediums and vegetation planting patterns have been designed and constructed in the open test fields in Xi~ an University of Technology. Purification effects of biological filters on pollutants in urban runoff and influencing factors have been analyzed based on the measured data of plot experiments. The results indicate that the purification effect of the fly ash is the best in the chosen matrixes and the removal rates of NH＋ --N, TN, DP, TP are respectively30%~45%, 25~30%, 90%~95%, and 60~90%. Compared to the biological filters without vegetation, the removal rate of TN has been raised 5% ~ 30% when the biological filters have plants, while the removal rates of DP and TP have no significant difference. With the increase of hydraulic load of inflow, the removal rate of pollutant is reduced. The removal rates of NH＋ --N and TN are 10% lower and DP and TP are 30% lower when the biological filter is under the condition of high hydraulic load than low hydraulic load. With the increases of concentration of pollutants, the removal rates of COD, DP, TP first increases and then decreases, while the removal rate of NH4＋ --N increases, and the removal rate of TN first decreases and then increases. With the continuation of inflow, the abilities of biological filter to reduce the inflow, inflow volume and inflow pollution load are decreased.