生物滞留设施对雨水径流热污染控制效果试验

Experimental study on thermal pollution control of stormwater runoff by bioretention

通过土柱模拟试验,采用人工模拟降雨的方法,研究了生物滞留设施在不同降雨历时、不同服务面积以及不同内部储水层高度条件下对雨水径流热污染的控制效果。结果表明:在进水温度为30℃的试验条件下,生物滞留设施对1年一遇雨水径流的热污染控制效果显著,在设施深度范围92.5~115.0 cm处土壤温度最低且最稳定;生物滞留设施服务面积一定时,随降雨历时的延长生物滞留设施对雨水径流热污染削减率呈现先增大后减小的趋势;降雨历时一定时,生物滞留设施对雨水径流的最佳热污染削减率随设施设计参数改变,其中生物滞留设施面积与其服务面积比是重要因素,该比值由1∶20增至1∶5,热污染削减率由23.19%增至38.02%,且出水温度较稳定;内部具有储水结构的生物滞留设施对热污染的控制效果较好。

The artificial rainfall method was used to create the simulated hydrograph,and soil column experiments were performed to examine the effect of bioretention on thermal pollution control of runoff,with different rainfall durations,different service areas,and different depths of internal water storage.The results showed that bioretention had a great thermal pollution control capacity under the experimental conditions,and soil temperature at a depth between 92.5 cm and 115.0 cm was the lowest and most stable.The reduction rate of rainfall thermal pollution firstly increased and then decreased with the extension of rainfall duration for the same service area,and the optimal thermal pollution reduction rate changed with bioretention design parameters accordingly.The ratio of bioretention area to its service area is an important factor,and the reduction rate of thermal pollution increased from 23.19%to 38.02%when the ratio increased from 1∶20 to 1∶5,with a decreasing fluctuation range of the effluent temperature.In addition,internal water storage structure can improve the effect of bioretention on thermal pollution control by intercepting runoff and promoting its infiltration to replenish groundwater.