摘要
通过耐受浓度试验得出凤眼莲、水蕹、水花生和荇菜四种植物对含重金属生活污水中Cd2+的耐受范围值分别<5mg/L、0.5mg/L、0.2mg/L、0.2mg/L;凤眼莲和水花生对Zn2+的耐受范围值分别<10mg/L,水蕹和荇菜对Zn2+耐受范围值为<5mg/L和0.5mg/L。由植物对生活污水中锌\镉离子去除率试验可知,在Cd2+/Zn2+浓度分别为0.5mg/L和5mg/L时,与对照组相比,两种植物均能明显去除污水中的Zn2+与Cd2+,其中Cd2+去除率提高了65.3%,Zn2+去除率提高了43.7%。研究发现植物处理在前5d内为去除Zn2+/Cd2+的高效区间,这一时期内植物对Zn2+/Cd2+去除率的贡献可以达到40%～60%,表明在植物的耐受浓度范围内,湿地植物对生活污水中的Cd2+/Zn2+有较好的去除效果,根部为主要的富集器官。
Experiments were carded out to test the ability of four selected plant species introduced into a constructed wetland system for removal of Zn^2＋ and Cd^2＋ from municipal wastewater mixed with lab wastewater. The highest concentration limit of Cd^2＋ that the selected species could endure was found to be 5, 0.5, 0.2 and 0.2mg/L respectively, for Eichhornia crassipes, Ipomoea aquatica, Alternanthera philoxeroide and Nymphoides peltatum, while that of Zn^2＋ was 10mg/L for Eichhornia crassipes and Alternanthera philoxeroide, 5mg/L for lpomoea aquatica and 0.5mg/L for Nymphoides peltatum. In the treatment experiments the two hydrophytes, Eichhornia crassipes and lpomoea aquatica, removed significant amount of Zn^2＋ and Cd^2＋ from the tested wastewater at concentration Zn^2＋ and Cd^2＋ of 0.5mg/L and 5mg/L. Compared to that in the control of the removal rate of Zn^2＋ and Cd^2＋ in plant treatment cells was enhanced by 45.7% and 65.3% respectively. A high treatment efficiency phase was observed in the first five days, within which the removal rate of Zn^2＋ and Cd^2＋ reached 40% and 60% respectively. Presence of such a high removal rate could be attributed to a root adsorption effect in the initial treatment period.
出处
《环境科学与技术》
CAS
CSCD
北大核心
2008年第12期164-168,共5页
Environmental Science & Technology
基金
国家林业局948项目"水环境保护中的湿地技术"(2005-4-31)
湖南省教育厅产业化推广项目"污水系列深度处理技术配套与推广"(2003-101)
关键词
人工湿地
植物
锌
镉
去除率
生活污水
constructed wetland
plant
Zn^2＋
Cd^2＋
removal rate
wastewater
