模拟生态种植槽对雨水径流的净化

为减少环湖公路路面径流对洱海水质的影响,该研究选用土壤、锯末、沙子、砾石分层装填的生态型的路面径流收集、净化和输送系统-生态种植槽(其中混合填料层锯末与沙子的配比设置3种比例1:3、1:4、1:5),研究该装置对模拟雨水的净化效果,并寻求最佳填充方式.结果表明,3组种植槽适合植物移栽、自然挂膜、低污染负荷启动方式;能稳定有效地去除COD、SS.运行期COD的平均出水水质优于地表水Ⅴ类水质,SS的平均去除率均高于80%.不同混合填料比种植槽对污水中COD的净化效果从高到低排序依次为: 1:5(锯末:沙子)> 1:4(锯末:沙子)> 1:3(锯末:沙子),方差分析显示,3组种植槽系统间COD、SS去除率无差异(P> 0.05),考虑到锯末:沙子为1:5时的渗透效果差,故推荐锯末:沙子为1:4的种植槽供后续示范工程选用.

Purification of stormwater runoff by ecological planting tank

To reduce the impact on Erhai Lake water quality by road surface runoff around the lake, ecological planting tank layered filling with soil, sawdust, sand and gravel(the mixed packing layer set three ratios of sawdust mixed sand:1:3, 1:4, 1:5), which was an ecological system of collection, purification and transport for road runoff, was used to study its treatment effect of stormwater runoff and seek the best fill style. The results reveal that the start-up process of planting tank can be well achieved by adoption of plant transplanting, natural biofilm formation and low influent load; the removal rates of COD and SS are high and stable. The average effluent COD concentration is below the value of grade-Ⅴ standard of surface water, the removal rates of SS are all more than 80%. COD purifying effects of different mixed packing ratio planting tank from high to low sequence in the order are 1:5 (sawdust:sand) >1:4 (sawdust:sand) > 1:3 (sawdust:sand), but no difference is observed for COD and SS removal rate between the three groups of planting tank(P >0.05). Considering that the permeation effect of sawdust mixed sand ratio of 1:5 is poor, planting tank with the ratio of 1:4 is recommended for subsequent demonstration project.