植草沟对苏南地区面源污染控制的案例研究

A Case Study on Control of Non-point Source Pollution by Grassed Swales in South Jiangsu

为探究植草沟对苏南地区面源污染的控制效果,同时为苏南地区构建海绵城市提供现场试验数据及理论依据,在2016年10月1日—28日,对常州市戚墅堰污水处理厂内的植草沟设施进行监测,考察大、中、小雨型下植草沟对道路径流水质及污染负荷的控制效果。结果表明,在大、中、小降雨事件中,道路径流各项指标大致呈现初期浓度较高、随后浓度不断降低的趋势,道路初期径流污染程度更大,且大雨时道路面源污染更严重; 3种雨型情况下植草沟对径流中SS和COD的去除效果良好且稳定,对二者的去除率分别在50%和30%以上,但对氮、磷污染物的去除效果不好,有氮、磷污染释放的现象发生;植草沟对地表径流污染负荷的削减率维持在较高水平,其中对SS和COD负荷的削减率超过了90%,对氮、磷污染负荷的削减率超过了80%。

Water quality of grassed swales in Qishuyan WWTP in Changzhou was monitored during October 1 to 28, 2016, and the control effects of grassed swales on water quality and pollution load of road runoff were investigated. The exploration not only desired to investigate the performance of grassed swales for controlling non-point source pollution in south Jiangsu but also provide field test data and theo- retical basis for construction of sponge city. The results indicated that the indexes of road runoff generally showed a trend of higher initial concentration, and then followed by a continuous decrease of concentra- tion in large, medium and small rainfall events. Road runoff pollution was more serious at the beginning, and road non-point source pollution was more serious in heavy rain. Grassed swales had stable removal ef- ficiencies of SS and COD in all 3 types of rainfall, and the removal efficiencies were over 50% and 30% respectively. However, the removal efficiencies of nitrogen and phosphorus were poor, and release of nitrogen and phosphorus occurred in the tests. The grassed swales maintained high removal efficiencies of the pollution load of the surface runoff. The reduction rates of SS and COD loads were over 90% , and the reduction rates of nitrogen and phosphorus loads were more than 80%.