Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing 100044, China.
Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing 100044, China.
Sci Total Environ. 2020 Aug 25;732:139248. doi: 10.1016/j.scitotenv.2020.139248. Epub 2020 May 11.
Green roofs can retain urban rainfall runoff, but there are doubts about whether they can reduce urban nonpoint source pollution. To explore the factors affecting the ability of green roofs to reduce nutrients in rainfall runoff, nine types of extensive green roofs (EGRs) were analysed during 38 natural rainfall events and two early spring irrigation runoff events from 1 March to 30 November 2019 in Beijing. Differences among the module scale, growing medium material, growing medium depth, drainage layer material, planting time, rainfall characteristics and seasonal variation were examined to study their correlation with pollutant event mean concentration (EMC) and the load reduction performance of EGRs. The results showed that EGRs had higher total nitrogen (TN), ammonia nitrogen (NH-N) and nitrate nitrogen (NO-N) concentrations than traditional concrete roofs, but total phosphorus (TP) concentrations were similar, and EGRs could reduce some of the nutrient loads. One-way analysis of variance showed that the module scale, growing medium material, growing medium depth, drainage layer material, and planting time had no significant effect on TN and NO-N concentrations (p > 0.05). The growing medium material had a significant effect on the TP concentration (p < 0.05). From the perspective of nutrient load reduction, module scale had a significant effect on TN and NH-N loads (p < 0.05). The growing medium depth had a significant effect on NH-N loads (p < 0.05). In addition, the growing medium material had a significant effect on TP loads (p < 0.05). When porous wool fibre and a bumpy plastic drainage board were selected as drainage layer materials, the effect on the NO-N load differed significantly. In other situations, there were no factors with significant differences. In addition, the rainfall characteristics and seasonal variation influenced the pollutant concentration and EGR runoff load.
绿色屋顶可以截留城市降雨径流，但对于其是否可以减少城市非点源污染仍存在疑问。为了探讨影响绿色屋顶截留降雨径流水体中养分能力的因素，于 2019 年 3 月 1 日至 11 月 30 日，在北京选取 9 种不同类型的粗放型绿色屋顶（EGR），在 38 场自然降雨和 2 场早春灌溉径流事件中，分析了模块规模、种植基质材料、种植基质深度、排水层材料、种植时间、降雨特征和季节变化等因素，研究其与污染物事件平均浓度（EMC）和 EGR 污染物负荷削减性能的相关性。结果表明，与传统的混凝土屋顶相比，EGR 具有更高的总氮（TN）、氨氮（NH-N）和硝酸盐氮（NO-N）浓度，但总磷（TP）浓度相似，且 EGR 可以减少部分养分负荷。单因素方差分析表明，模块规模、种植基质材料、种植基质深度、排水层材料和种植时间对 TN 和 NO-N 浓度没有显著影响（p＞0.05）。种植基质材料对 TP 浓度有显著影响（p＜0.05）。从养分负荷削减的角度来看，模块规模对 TN 和 NH-N 负荷有显著影响（p＜0.05）。种植基质深度对 NH-N 负荷有显著影响（p＜0.05）。此外，种植基质材料对 TP 负荷有显著影响（p＜0.05）。当选择多孔羊毛纤维和凹凸塑料排水板作为排水层材料时，对 NO-N 负荷的影响差异显著。在其他情况下，没有因素具有显著差异。此外，降雨特征和季节变化也会影响污染物浓度和 EGR 径流水体的负荷。
