管道沉砂用作雨水花园土壤改良材料的可行性

以建筑黄砂为对照,采用排水管道清通作业产生的管道沉砂作为提高土壤渗透性能的改良材料,通过模拟土柱实验考察了雨水花园对路面径流污染的控制效果.实验结果表明,在装置初始运行阶段,模拟柱中污染物的淋出浓度迅速降低,污染地下水的风险很低;当污染物淋失达到稳定时,掺加同比例管道沉砂与建筑黄砂的模拟柱在提高土壤渗透速率方面效果相近,而对COD、TP、TSS、NH4+-N、NO3--N、重金属等污染物的去除两者效果则相差不大.结果表明,以管道沉砂作为土壤改良材料,在降低南方粘性土壤地区雨水花园的建造成本、实现废弃物的再利用方面具有良好前景.

Feasibility of applying sewer silt as soil permeability improver for rain garden facility

The feasibility of using sewer silt as soil permeability improver for rain garden facility was evaluated with construction sand as a control. In this study, model columns were developed to investigate the runoff pollutants removal efficiencies of rain garden. The results indicated that there would be little groundwater pollution caused by sewer silt for initiate effluent pollutants concentration of the model columns decreased sharply. As the pollutants leaching became stable , permeability improving effect of sewer silt was as good as construction sand to silty clay provided the adding rate to the clay was the same, moreover, surface runoff pollutants removal efficiency of COD, TP, TSS, NH₄⁺-N, NO₃^--N and heavy metals between the two media were about the same. Experimental results suggested that the application of sewer silt as soil permeability improver have good prospects in cost reduction of rain garden construction and waste recycling.