基于绿色基础设施的城市非点源污染控制研究

以珠海市西部新城为例，通过监测采样分析现状城市降雨径流污染特征和规划前后城市非点源污染负荷，采用雨洪管理模型（SWMM）模型构建6种基于不同绿色基础设施技术的污染控制情景，并评估分析各情景下的成本效益.结果表明：现状建成区道路和地面铺装的径流污染较重（劣Ⅴ类）；屋顶和地面的初期径流冲刷效应明显；规划后城市径流污染物排放负荷增加至现状的2.9~3.2倍.组合型方案（源头型组合、源头-末端组合）的污染综合控制效果优于单技术方案，但其污染物单位削减成本较高；单技术方案中，末端型的调节塘对各污染物的单位削减成本均最低，且对TN、TP的削减效果较好；源头型的生物滞留池和植草浅沟的单位削减成本也较低，但污染物削减效果较差；而透水铺装的单位削减成本较高.总之，单项技术方案在污染控制的成本效益表现上要优于组合型方案，若要取得更好的污染控制果，则还需投入更大的成本，采取组合型方案进行污染控制.研究可为当前快速城市化新区海绵城市的多目标决策提供科学依据.

Study for green infrastructure approach on urban non-point source pollution control

This study aimed to: (i) characterize the runoff pollution before and after urbanization; (ii) analyze the cost-effectiveness of different GI strategies and their combinations (CGIs); and (iii) provide the scientific basis for Multi-Objective Decision-Making for the Sponge City planning. Using the rapidly developing Western New City of Zhuhai as the case study, we analyzed the characteristics of the current urban rainfall-runoff pollution and the changes of pollution load before and after planning through field monitoring. To evaluate the performance and cost-effectiveness, six GI and CGI scenarios were considered with the use of SWMM modeling. The results indicated that: (1) under the current condition, heavy runoff pollution (inferior to water quality class V) was identified for roads and paved ground in the developed areas; (2) there existed obvious initial flush effect from roofs and ground; (3) after development, the runoff pollutant loads were 2.9~3.2 times as those under current conditions; (4) the CGI (source/source-terminal controls) yielded better overall performance than the single GIs, however its cost per unit of pollutant reduction was higher; (5) among the single GIs, the detention basin yielded the lowest cost per unit of reduction, and it also effectively reduced TN and TP; (6) bio-retention and vegetated swale also yielded low reduction cost, but they could not effectively reduce the pollutant load; and (7) the reduction cost per unit of permeable pavement is the most expensive among all considered single GI strategies. Overall, the cost-effectiveness performance of single GI was superior to the CGI in pollution control. The single GI strategies were more cost-effective compared to CGI strategies; however it was necessary to invest more to adopt the CGI strategies in order to achieve better pollution control results.