Department of Engineering, University of Ferrara, Via Saragat 1, I-44122 Ferrara, Italy.
Sci Total Environ. 2010 Oct 1;408(21):5097-105. doi: 10.1016/j.scitotenv.2010.07.045. Epub 2010 Aug 9.
This study investigated the accumulation and removal of Cu, Ni and Zn in two horizontal subsurface flow constructed wetlands for domestic wastewater treatment, which differ by shape, presence of macrophytes and water depth. Between March and December 2007, the three metals were measured in the influent and effluents of the two systems. Average percentage removal rates were extremely low for Cu (3% and 9% in the two beds) and higher for Zn and Ni (between 25 and 35%). Under higher Zn influent concentrations, it was found to be between 78-87%, which is in agreement with other literature data. During the peak standing crop season (August), biomasses of the different parts of Phragmites australis (stems, leaves and flowers, roots and rhizomes) were analysed in terms of weight and heavy metal concentration in order to assess heavy metal distribution among the tissues. It was found that the plants contribute to total heavy metal removal to a lesser extent than the filling medium. Aboveground tissues remove 34% of Cu, 1.8% of Ni and 6.2% of Zn % and, once harvested, their disposal does not appear to pose a problem for the environment. If heavy metals are present at high concentrations in the horizontal subsurface flow bed influent, over time, their accumulation in the filling medium could necessitate special care in the bed's management to avoid release into the surrounding environment.
本研究调查了两种不同形状、有无大型植物和水深的水平潜流人工湿地对生活污水中 Cu、Ni 和 Zn 的积累和去除。2007 年 3 月至 12 月，在两个系统的进水和出水处测量了这三种金属。Cu 的平均去除率极低（两个床中的 3%和 9%），而 Zn 和 Ni 的去除率较高（25%至 35%之间）。在较高的 Zn 进水浓度下，发现其去除率在 78-87%之间，这与其他文献数据一致。在高峰期（8 月），对芦苇（茎、叶和花、根和根茎）的不同部分的生物量进行了分析，以评估重金属在组织间的分布。结果发现，植物对总重金属去除的贡献小于填充介质。地上组织去除了 34%的 Cu、1.8%的 Ni 和 6.2%的 Zn，一旦收获，其处置似乎不会对环境造成问题。如果水平潜流床进水口的重金属浓度很高，随着时间的推移，它们在填充介质中的积累可能需要特别注意床的管理，以避免释放到周围环境中。
