Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Environment and Ecology, Chongqing University, Chongqing, 400045, China.
Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Environment and Ecology, Chongqing University, Chongqing, 400045, China.
J Environ Manage. 2024 Jul;364:121448. doi: 10.1016/j.jenvman.2024.121448. Epub 2024 Jun 13.
Submerged zone in bioretention facilities for stormwater treatment has been approved to be an effective structure amendment to improve denitrification capability. However, the role and influence of water quality changes in the submerged zone under natural continuous random rainfall patterns are still not clear, especially when the rainfall is less than the pore water in the submerged zone. In this study, continuous rainfall events with different rainfall volume (light rain-light rain-heavy rain) were designed in a lab-scale woodchip mulched pyrite bioretention facility to test the effects of rainfall pattern. The results exhibited that light rain events significantly affected the pollutant removal performance of bioretention for the next rainfall. Different effects were observed during the long-term operation. In the 5th month, light rain reduced the ammonia removal efficiency of subsequent rainstorm events by 8.70%, while in the 12th month, when nitrate leakage occurred, light rain led to a 40.24% reduction in the next heavy rain event's nitrate removal efficiency. Additionally, light rain would also affect the concentration of by-products in the next rainfall. Following a light rain, the concentration of sulfate in the subsequent light rainfall can increase by 24.4 mg/L, and by 11.92 mg/L in a heavy rain. The water quality in the submerged zone and media characteristics analysis suggested that nitrogen conversion capacity of the substrate and microbes, such as Nitrospira (2.86%) and Thiobacillus (35.71%), as well as the in-situ accumulation of pollutants under light rain played important roles. This study clarifies the relationship between successive rainfall events and provides a more comprehensive understanding of bioretention facilities. This is beneficial for field study of bioretention facilities in the face of complex rainfall events.
生物滞留设施中的淹没区已被批准为一种有效的结构改良措施，以提高反硝化能力。然而，在自然连续随机降雨模式下，淹没区中水质变化的作用和影响仍不清楚，尤其是在降雨量小于淹没区中的孔隙水时。本研究在实验室规模的木屑覆盖黄铁矿生物滞留设施中设计了不同降雨量（小雨-小雨-大雨）的连续降雨事件，以测试降雨模式的影响。结果表明，小雨事件显著影响了生物滞留对下一次降雨的污染物去除性能。在长期运行中观察到不同的影响。在第 5 个月，小雨降低了后续暴雨事件中氨氮去除效率 8.70%，而在第 12 个月，当硝酸盐泄漏发生时，小雨导致下一次大雨事件中硝酸盐去除效率降低了 40.24%。此外，小雨还会影响下一次降雨中的副产物浓度。在小雨之后，下一次小雨中硫酸盐的浓度会增加 24.4 mg/L，大雨中会增加 11.92 mg/L。淹没区的水质和介质特性分析表明，氮转化能力的基质和微生物，如 Nitrospira（2.86%）和 Thiobacillus（35.71%），以及小雨下污染物的原位积累，都起到了重要作用。本研究阐明了连续降雨事件之间的关系，为生物滞留设施提供了更全面的认识。这有利于在面对复杂降雨事件时对生物滞留设施进行现场研究。
