Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, 518055 Shenzhen, China.
Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, 518055 Shenzhen, China.
J Environ Manage. 2019 Mar 1;233:748-756. doi: 10.1016/j.jenvman.2018.09.082. Epub 2018 Oct 10.
Sewer interception systems have been built along rivers in rapidly urbanizing areas to collect unregulated sewage discharges due to misconnections between storm sewers and sanitary sewers. During storm events, combined sewage might overflow from these systems into rivers through orifices and deteriorate water quality in rivers. Interception system overflows (ISOs) from different orifices in a sewer interception system might interact with each other, therefore pollutants from ISOs show a spatial variation. This paper aims to understand the spatial variation of pollutants from ISOs for informed decision making. In this study, an urbanized catchment in China is chosen as the study area, and the Storm Water Management Model (SWMM) is used to examine the spatial variation of pollutants from ISOs and to analyze the effect of sewer separation on ISOs. The results obtained from the case study indicate that: (1) Critical rainfall amounts which trigger overflows decrease downstream in an interception system while annual ISO volumes and pollutant loads from ISOs increase downstream; additionally, these variations are influenced by sizes and slopes of interceptors; (2) Runoff is the main source of COD from ISOs while sewage is the main source of NH-N, and ratios of pollutants from sewage to ISOs increase downstream; (3) Sewer separation can significantly reduce pollutant loads from sewage to ISOs, but it cannot significantly reduce pollutant loads from runoff. In order to mitigate ISO pollution, it is suggested to increase conveyance capacities of interceptors in the downstream, separate sewage from runoff, and promote source control for urban runoff in highly urbanized areas.
污水截流系统已沿快速城市化地区的河流建造，以收集因雨水下水道和污水下水道之间的错误连接而导致的未经监管的污水排放。在风暴事件期间，合流污水可能会通过这些系统中的孔口从这些系统中溢出到河流中，并导致河流水质恶化。污水截流系统溢流（ISO）可能会相互作用，因此来自 ISO 的污染物表现出空间变化。本文旨在了解 ISO 中污染物的空间变化，以便做出明智的决策。在本研究中，选择中国的一个城市化流域作为研究区域，并使用雨水管理模型（SWMM）来检查 ISO 中污染物的空间变化，并分析下水道分离对 ISO 的影响。案例研究的结果表明：（1）引发溢流的临界降雨量在截流系统中随下游而下降低，而 ISO 的年体积和污染物负荷随下游而增加；此外，这些变化受截流井的尺寸和坡度的影响；（2）径流是 ISO 中 COD 的主要来源，而污水是 NH-N 的主要来源，污水中污染物与 ISO 的比例随下游而增加；（3）下水道分离可以显著降低污水向 ISO 的污染物负荷，但不能显著降低径流向 ISO 的污染物负荷。为了减轻 ISO 污染，建议增加下游截流井的输送能力，将污水与径流分离，并在高度城市化地区促进对城市径流的源头控制。
