University of Florida, Institute of Food and Agricultural Sciences, Department of Soil and Water Sciences/Indian River Research and Education Center, Fort Pierce, FL, 34945, USA.
University of Florida, Institute of Food and Agricultural Sciences, Department of Soil and Water Sciences/Indian River Research and Education Center, Fort Pierce, FL, 34945, USA.
J Environ Manage. 2021 Feb 15;280:111794. doi: 10.1016/j.jenvman.2020.111794. Epub 2020 Dec 17.
A community of aquatic macrophytes has an important role in reducing nutrient load and organic and inorganic contaminants in storm/runoff water. However, minimal information is available regarding the efficiency of constructed wetlands for cleaning runoff water from urban areas, especially in the tropical and subtropical regions. This study investigated the effectiveness of constructed wetland integrated with aquatic macrophytes for removal of chemical and microbial contaminants in the storm/runoff water from the urban areas. Water samples were monthly collected in the constructed wetland from the inlet of storm/runoff water, middle and outlet of discharge, and analyzed for physical and chemical properties, concentrations of nutrients, metals, and fecal coliform (FC) during the period of November, 2016 to April, 2018 in St. Lucie county, Florida, USA. The dominant plant species in the constructed wetland included cattail (Typha latifolia), waterthyme (Hydrilla verticillata) and water hyacinth (Eichhornia crassipes), and periphyton filamentous algae (Spirogyra). The improvement of pH and electrical conductivity (EC) was not obvious, but the concentration of total suspended solids was significantly reduced. This system was effective in the removal of fecal coliform (by 68%) and particulate phosphorus (P, 72%), followed by total P (42%) and N (35%). Concentrations of metallic pollutants including cadmium (Cd), lead (Pb), chromium (Cr), and copper (Cu) were mostly below the detection limit (<1 ppb) except for zinc (Zn), of which concentration was reduced by 23%. The removal of FC was consistently effective all the year round, whereas the removal of total N, P and particulate-P was effective in spring and summer, and less in autumn and winter. These results indicate that constructed wetland with a natural aquatic plant community can effectively reduce the loads of nutrients, metals, and fecal coliforms in water column. Regular harvest of aquatic macrophytes communities and collecting litters may further improve the system efficiency for cleaning storm water from urban areas.
水生植物群落对于减少雨水和径流水体中的营养负荷、有机和无机污染物具有重要作用。然而，有关人工湿地对城市雨水径流水体净化效果的信息却很少，特别是在热带和亚热带地区。本研究调查了水生植物人工湿地对去除城市雨水径流水体中化学和微生物污染物的有效性。2016 年 11 月至 2018 年 4 月期间，在美国佛罗里达州圣卢西亚县的人工湿地进水口、中部和出水口每月采集雨水和径流水体样本，分析理化性质、营养物、金属和粪大肠菌群（FC）浓度。人工湿地中的优势植物物种包括香蒲（Typha latifolia）、水薄荷（Hydrilla verticillata）和凤眼蓝（Eichhornia crassipes）以及丝状藻类（Spirogyra）。尽管 pH 值和电导率（EC）的改善不明显，但总悬浮固体浓度显著降低。该系统对粪大肠菌群（去除率为 68%）和颗粒态磷（P，去除率为 72%）的去除效果较好，其次是总磷（去除率为 42%）和总氮（去除率为 35%）。除锌（Zn）外，大部分金属污染物（包括镉（Cd）、铅（Pb）、铬（Cr）和铜（Cu））浓度均低于检测限（<1 ppb），而锌的浓度则降低了 23%。FC 的去除效果全年较为稳定，而总氮、总磷和颗粒态磷的去除效果在春夏季较好，秋冬季较差。这些结果表明，自然水生植物群落人工湿地可以有效地减少水体中的营养物、金属和粪大肠菌群负荷。定期收获水生植物群落并收集枯枝落叶可能会进一步提高系统对城市雨水的净化效率。
