细数植物在人工湿地污水处理中的作用

Counting the Roles of Plants in Constructed Wetlands for Wastewater Treatment

天然的湿地植物在形态和解剖学上均能适应氧含量较低的生态环境,因此,它们可用于人工湿地系统中处理污水。而人工湿地中的植物不仅将人工湿地与稳定塘区分开,同时为污染物的去除创造适合的条件。人工湿地中的植物不仅能减弱强光与风力对湿地的影响,为湿地基质提供保温作用,满足根区微生物生长对氧气和其他营养成分的需求,还能截留部分污染物预防湿地堵塞,并具有其特有的美学价值,在不同类型的人工湿地中发挥不同程度的作用。最常见的人工湿地植物有漂浮植物如凤眼莲、浮萍;沉水植物如狐尾藻属、金鱼藻属;挺水植物如芦苇、香蒲属。而国内人工湿地除了以上这些常见植物外,还常用一些其他的沉水植物,比如芦竹、再力花、风车草以及美人蕉等。

Wetland plants can morphologically and anatomically adapt to the ecological environment with reduced oxygen conditions and therefore,they can be used in constructed wetlands(CWs)for wastewater treatment.The presence of plants distinguishes CWs from stabilization ponds where plants are not intentionally planted.The plants are important for the treatment process as they provide many roles and create suitable conditions for removal of pollution.The most important roles include insulation of the filtration bed,light and wind attenuation,provision of oxygen to the rhizosphere,nutrient uptake,clogging prevention and aesthetic value.These roles are applicable to various extents depending on the type of CWs.The most common plants used in CWs are free floating Eichhornia crassipes and Lemna spp.,submerged Myriophyllum spp.and Ceratophyllum spp.,and emergent Phragmites australis and Typha spp.These plants are used in China but other emergent species such as Arundo donax,Thalia dealbata,Cyperus alternifolius or Canna indica are also commonly used.