Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China.
Qingdao Planning Engineering Design Research Institute Co., Ltd., Qingdao, 266000, China.
Environ Sci Pollut Res Int. 2023 Mar;30(15):44591-44606. doi: 10.1007/s11356-023-25305-0. Epub 2023 Jan 25.
A series of complex physical and chemical processes, such as interception, migration, accumulation, and transformation, can occur when pollutants in stormwater runoff enter the growing media layer of bioretention facilities, affecting the purification of stormwater runoff by bioretention facilities. The migration and accumulation of pollutants in the growing media layer need long-term monitoring in traditional experimental studies. In this study, we established the Hydrus-1D model of water and solution transport for the bioretention facilities. By analyzing the variation of cumulative fluxes of NO-N and Pb with time and depth, we investigated pollutant migration and accumulation trends in the growing media layer of bioretention facilities. It can provide support for reducing runoff pollutants in bioretention facilities. The Hydrus-1D model was calibrated and verified with experimental data, and the input data (runoff pollutant concentration) for the pollutant concentration boundary was obtained from the SWMM model. The results demonstrated that the cumulative fluxes of NO-N and Pb increased with the passage of simulation time and depth of the growing media layer overall. From the top to the bottom of the growing media layer, the change rates of the peak cumulative fluxes of NO-N and Pb were strongly linked with their levels in the runoff. An increase in rainfall decreased the content of NO-N and Pb in the growing media layer, and this phenomenon was more obvious in the lower part of the layer.
当雨水径流中的污染物进入生物滞留设施的生长介质层时，会发生一系列复杂的物理和化学过程，如拦截、迁移、积累和转化，从而影响生物滞留设施对雨水径流的净化效果。在传统的实验研究中，需要对生长介质层中污染物的迁移和积累进行长期监测。本研究建立了生物滞留设施水和溶质运移的 Hydrus-1D 模型。通过分析 NO-N 和 Pb 的累积通量随时间和深度的变化，研究了生物滞留设施生长介质层中污染物的迁移和积累趋势。该模型可以为减少生物滞留设施中的径流污染物提供支持。利用实验数据对 Hydrus-1D 模型进行了校准和验证，污染物浓度边界的输入数据（径流污染物浓度）则来自 SWMM 模型。结果表明，NO-N 和 Pb 的累积通量随模拟时间和生长介质层深度的增加而整体增加。从生长介质层的顶部到底部，NO-N 和 Pb 的峰值累积通量的变化率与其在径流中的水平密切相关。降雨量的增加降低了生长介质层中 NO-N 和 Pb 的含量，且这种现象在层的下部更为明显。
