生物滞留系统对城市路面径流的净化性能小型试验与模拟

Small Scale Experiment and Simulation of Purification Performance of Bioretention System on Urban Road Surface Runoff

为研究生物滞留系统对西北典型城市路面径流的净化性能,设计了多组不同结构的生物滞留小型试验柱,通过室外试验、数理统计和模型模拟,研究填料类型、填料厚度、淹没区深度、植物种类等因素对生态滞留设施水质净化效果的影响。研究表明:沙子和粉煤灰混合填料对污染物的综合去除率为85.03%,净化效果最佳;增加人工填料厚度可以提高对污染物浓度的净化效果,在40,50,60cm 3种厚度对比下,填料厚度为60cm时,综合去除率为56.61%,污染物净化效果最佳;淹没区深度的变化对氮素净化效果的影响比较明显,在20,30,40cm 3种淹没区深度下,40cm淹没区深度时TN去除率为50.84%,净化效果最佳;黄杨和黑麦草植物组合净化效果最佳,在NO_3^--N的净化效果方面,相比于水蜡+麦冬草,前者可将净化效果提升10%左右。建立了生物滞留系统净化效果与各影响因素的多元线性回归模型,模拟精度良好。采用Hydrus-1D模型对TN在生态滞留系统中的迁移进行模拟,结果可靠。

Bioretention is a typical low-impact development（LID）technology.In order to study the purification performance of bioretention system on urban road runoff in northwest China,multiple sets of small scale bioretention columns with different structure were designed.Through outdoor experiments,mathematical statistics and model simulation,the influences of such factors as filler type,filler thickness,submerged zone depth and plant species on the removal of pollutants in bioretention facility were studied.The results showed that：The mixed filler of sand and fly ash worked best for the removal of all pollutants,reaching 85.03%comprehensive removal rate;the increase of artificial filler thickness could improve the pollutant purification effect.Under three thicknesses of 40 cm,50cm and 60 cm,the purification effect of filler thickness with 60 cm was the best,getting 56.61%comprehensive removal rate;the influence of submerged zone depth on the nitrogen purification effect was obvious.Under three submerged zone depths of 20 cm,30cm and 40 cm,the TN purification effect of the depth with 40 cm was the best,with the removal rate of 50.84%;the purification effect of the combination of Buxus sinica and Lolium perenne was the best,and in term of NO3^--N purification effect,compared to Ligustrum obtusifoliumand Ophiopogon japonicus,the former could enhance the purification effect by 10%approximately.The multiple linear regression models between the purification effects of bioretention system and the influencing factors were established,having high simulation accuracy.The Hydrus-1D model was applied to simulate the migration of total nitrogen in bioretention system,reaching the reliable results.