Lin Xiu-Yong, Wang Shu-Min, Li Qiang, Xie Yun-Cheng
Chongqing Key Laboratory of Environmental Material and Restoration Technology, Yongchuan 402160, China.
Department of Civil Engineering, Fuzhou University, Fuzhou 350116, China.
Huan Jing Ke Xue. 2018 Oct 8;39(10):4539-4546. doi: 10.13227/j.hjkx.201801074.
Bioretention cells have become one of the most popular devices in urban stormwater runoff management for their high efficiency in reducing runoff volume and pollution loads. However, bioretention cells are unstable in nutrient pollutant removal, as is verified by many cases, especially at low temperatures. Dissolved organic matters (DOMs) plays an important role in denitrification, but the three-dimensional fluorescence characteristics of stormwater runoff in bioretention field cells are poorly understood, so to improve the performance of bioretention cells in nutrient pollutants control, the authors determined that it was necessary to clarify the characteristics of three-dimensional fluorescence of stormwater runoff from bioretention cells and explain their relationship to water quality. To be applicable to urban landuse in mountainous cities, two field lined bioretention cells were constructed, and, from March to April in 2017, while temperatures were still low, water quality and three-dimensional fluorescence of stormwater runoff were analyzed during low rainfall intensity precipitation events. Analysis results showed that the effluent pollutant concentrations had low fluctuation after purification by the bioretention cells, and both cells showed relatively stable removal rates for NH-N and total phosphorus (TP; i. e., 78.38%-95.03% and 72.04%-76.04%, respectively). Analysis of fluorescence spectra showed that the DOMs in the runoff from the two cells was mostly made up of protein and humic substances, mainly of biological origin or aquatic bacterial metabolites. Both cells performed well in the removal of protein at I, protein at Ⅱ and fulvic acid (i. e., the removal rates could reach 57.33%-61.30%, 29.82%-31.28%, and 35.55%-43.16% respectively). Correlation analyses between water quality and DOM showed that total Nitrogen (TN), TP and total organic carbon (TOC) were positively correlated with the protein content in runoff from the biorentention cells, while NO-N and NH-N were negatively correlated with protein content. Meanwhile, TN was negatively correlated with DOMs in regions Ⅳ and Ⅴ of the cells.
生物滞留池因其在减少径流量和污染负荷方面的高效性，已成为城市雨水径流管理中最受欢迎的设施之一。然而，正如许多案例所证实的那样，生物滞留池在去除营养污染物方面并不稳定，尤其是在低温情况下。溶解有机物（DOMs）在反硝化过程中起着重要作用，但对生物滞留池中的雨水径流三维荧光特性了解甚少。因此，为了提高生物滞留池在控制营养污染物方面的性能，作者认为有必要阐明生物滞留池雨水径流的三维荧光特性，并解释它们与水质的关系。为了适用于山地城市的城市土地利用，构建了两个带衬里的现场生物滞留池，并在2017年3月至4月期间，在气温仍然较低时，对低降雨强度降水事件期间的雨水径流水质和三维荧光进行了分析。分析结果表明，经生物滞留池净化后，出水污染物浓度波动较小，两个池子对NH-N和总磷（TP）均表现出相对稳定的去除率（分别为78.38%-95.03%和72.04%-76.04%）。荧光光谱分析表明，两个池子径流中的DOMs主要由蛋白质和腐殖质组成，主要来源于生物或水生细菌代谢产物。两个池子在去除Ⅰ类蛋白质、Ⅱ类蛋白质和富里酸方面表现良好（去除率分别可达57.33%-61.30%、29.82%-31.28%和35.55%-43.16%）。水质与DOM的相关性分析表明，总氮（TN）、TP和总有机碳（TOC）与生物滞留池径流中的蛋白质含量呈正相关，而NO-N和NH-N与蛋白质含量呈负相关。同时，TN与池子Ⅳ区和Ⅴ区的DOMs呈负相关。
