Hatt Belinda E, Fletcher Tim D, Deletic Ana
Facility for Advancing Water Biofiltration, Department of Civil Engineering, Monash University, 3800 Victoria, Australia.
Environ Sci Technol. 2008 Apr 1;42(7):2535-41. doi: 10.1021/es071264p.
Stormwater runoff from urban areas has multiple negative hydrologic and ecological impacts for receiving waters. Fine media stormwater filtration systems have the potential to mitigate these effects, through flow attenuation and pollutant removal. This work provides an overall assessment of the hydraulic and pollutant removal behavior of sand- and soil-based stormwater filters at the laboratory scale. The influence of time, cumulative inflow sediment, cumulative water volume, wetting and drying, and compaction on hydraulic capacity was investigated. The results suggested that the primary cause of hydraulic failure was formation of a clogging layer at the filter surface. Loads of sediment and heavy metals were effectively retained; however,the soil-based filters leached nitrogen and phosphorus for the duration of the experimental period. Media pollutant profiles revealed significant accumulation of all pollutants in the top 20% of the filter profile, suggesting that elevated discharges of nutrients was due to leaching of native material, rather than failure to remove incoming pollutants. It is recommended that the top 2-5 cm of the filter surface be scraped off every two years to prevent hydraulic failure; this will also avoid excessive accumulation of heavy metals, which may otherwise have been of concern.
城市地区的雨水径流对受纳水体具有多种负面水文和生态影响。精细介质雨水过滤系统有潜力通过流量衰减和污染物去除来减轻这些影响。这项工作在实验室规模上对基于沙子和土壤的雨水过滤器的水力性能和污染物去除行为进行了全面评估。研究了时间、累积入流沉积物、累积水量、干湿循环和压实对水力性能的影响。结果表明，水力失效的主要原因是在过滤器表面形成了堵塞层。沉积物和重金属负荷得到有效截留；然而，在实验期间，基于土壤的过滤器会淋溶出氮和磷。介质污染物分布表明，所有污染物在过滤器剖面顶部20%的区域有显著积累，这表明营养物质的排放增加是由于原生材料的淋溶，而不是未能去除进入的污染物。建议每两年刮除过滤器表面顶部2 - 5厘米，以防止水力失效；这也将避免重金属的过度积累，否则这可能会令人担忧。
