下沉式绿地对雨水径流污染物的削减效果及影响因素分析

为探究下沉式绿地对雨水径流污染物的削减效果及影响因素,采用室外种植箱的方式进行模拟试验,研究不同植物配置、不同下垫面雨水径流、不同土壤层厚度以及不同污染物浓度对下沉式绿地削减污染物的影响。结果表明,不同植物配置的下沉式绿地对削减NH+4-N的影响差值为9.6%,即依次:高羊茅(57.3%)三种混合植物(55.0%)鸢尾(50.4%)鼠尾草(47.7%);对削减TP的影响差值为5.3%,即依次:高羊茅(56.4%)三种混合植物(54.4%)鼠尾草(53.8%)鸢尾(51.1%);对削减COD的影响差值为8.9%,即依次:三种混合植物(39.4%)高羊茅(37.8%)鸢尾(33.1%)鼠尾草(30.5%)。不同植物配置的下沉式绿地对重金属(Cu、Zn、Pb)的削减效果很好,达95%以上。下沉式绿地对三种下垫面雨水径流污染物的削减效果依次:硬质屋顶沥青路面绿地;不同土壤层厚度和污染物浓度对下沉式绿地削减常规污染物的影响呈正相关,对下沉式绿地削减重金属的影响不大。因此,本研究可为下沉式绿地在控制雨水径流污染问题提供一种优化途径的新思路。

Study the reduction effect and influence factors of the sunken green space on stormwater runoff pollutant

In order to explore the reduction effect and influence factors of the sunken green space on stormwater runoff pollutant, by the outdoor planting box simulation experiment, studying the impact of different plant configuration, different underlying surface stormwater runoff, different soil thickness and different pollutant concentrations of sunken green space pollutant reduction. The results show that the influence on the reduction of NH+ 4-N of the difference is 9.6% by different plant configuration in the sunken green space, which in turn: tall fescue (57.3%) > three hybrid plants (55.0%) > iris (50.4%) > sage (47.7%); influence on the reduction of TP of the difference is 5.3%, which is in turn: tall fescue (56.4%) > three hybrid plants (54.4%) > sage (53.8%) > iris (51.1%); influence on the reduction of COD of the difference is 8.9%, which in turn: three hybrid plants (39.4%) > tall fescue (37.8%) > iris (33.1%) > sage (30.5%). The reduction of heavy metals (Cu, Zn, Pb) by different plant configuration in the sunken green space is very good, reaching more than 95%. The effect of sunken green space on reducing stormwater runoff pollutant of three underlying surfaces is in turn: hard roof > asphalt pavement > greenland; The impact of different thickness of soil layer and pollutant concentration of sunken green space reduces conventional pollutants of are positively correlated, has little effect on the reduction of heavy metals of sunken green space. Therefore, this study can provide a new way to optimize the way to control stormwater runoff pollution in sunken green space.