Poggioli Marisa, Cavadini Giovan Battista, Zheng Zhaozhi, Rodriguez Mayra, Mutzner Lena
Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland.
Institute of Civil, Environmental and Geomatic Engineering, ETH Zürich, 8093, Zurich, Switzerland.
Water Res X. 2024 Sep 27;25:100261. doi: 10.1016/j.wroa.2024.100261. eCollection 2024 Dec 1.
Blue-green infrastructure (BGI) reduce urban combined sewer overflows (CSOs) and stormwater outlets (SWOs). However, most conventional BGI are not designed to remove trace organic contaminants. Little is known about the potential of conventional BGI to improve surface water quality by reducing the discharge of trace organic contaminants. We derived wash-off loads for street runoff (6PPD-q, DPG, and HMMM), construction materials (diuron), and wastewater-derived contaminants (diclofenac) based on measurements in the combined sewer system. Subsequently, the performance of four BGI types (bioretention cells, green roofs, porous pavements, and urban wetlands) to reduce the discharge of trace organic contaminants via SWOs and CSOs was quantified with a hydrodynamic SWMM model. Moreover, the catchment-wide impact of SWOs and CSOs on surface water was assessed using risk quotients. We found that the annually discharged load can be considerably reduced by implementing BGI. Among the studied BGI types, bioretention cells are the most effective, with a load reduction of up to 80% to surface waters, mainly due to a larger suitable implementation area and a substantial stormwater infiltration. BGI implemented in the separate sewer system are more effective in reducing stormwater contaminant loads than BGI in the combined system. The assessment of the risk quotient in the surface water showed that the concentrations during SWO and CSO discharges exceed the acute environmental threshold in the surface water for 6PPD-q, DPG, diuron, and diclofenac during several events. The implementation of BGI reduced the hours of exceeded risk quotient in the surface water by 93% for bioretention cells. These findings underscore the need for a catchment-wide assessment of future BGI implementations to quantify, manage, and mitigate the impacts of urban pollution.
蓝绿基础设施（BGI）可减少城市合流制污水溢流（CSO）和雨水排放口（SWO）。然而，大多数传统的蓝绿基础设施并非设计用于去除痕量有机污染物。对于传统蓝绿基础设施通过减少痕量有机污染物排放来改善地表水水质的潜力，人们了解甚少。我们基于对合流制排水系统的测量，得出了街道径流（6PPD - q、二苯胺和六甲基三聚氰胺）、建筑材料（敌草隆）和废水衍生污染物（双氯芬酸）的冲刷负荷。随后，利用水动力SWMM模型对四种蓝绿基础设施类型（生物滞留池、绿色屋顶、多孔路面和城市湿地）通过雨水排放口和合流制污水溢流减少痕量有机污染物排放的性能进行了量化。此外，还使用风险商数评估了雨水排放口和合流制污水溢流对整个流域地表水的影响。我们发现，实施蓝绿基础设施可大幅减少年度排放负荷。在所研究的蓝绿基础设施类型中，生物滞留池最为有效，可使进入地表水的负荷减少高达80%，这主要得益于更大的适宜实施面积和大量的雨水入渗。在分流制排水系统中实施的蓝绿基础设施比合流制系统中的蓝绿基础设施在减少雨水污染物负荷方面更有效。对地表水中风险商数的评估表明，在几次事件中，雨水排放口和合流制污水溢流期间的6PPD - q、二苯胺、敌草隆和双氯芬酸浓度超过了地表水的急性环境阈值。生物滞留池实施蓝绿基础设施后，地表水中风险商数超标小时数减少了93%。这些发现强调了对未来蓝绿基础设施实施进行全流域评估的必要性，以量化、管理和减轻城市污染的影响。
