再力花强化人工湿地除汞效能的试验研究

Experiments on enhancing mercury removal efficiency of constructed wetlands with Thalia dealbata Fraser

环境中的汞可以通过沉降进入生态系统,各类水体也因人类生产活动受到汞污染的威胁,人工湿地作为一种常用的水质净化技术对重金属有良好的去除效果。通过围绕湿地去除汞的效能,开展湿地植物再力花的含汞营养液水培试验,考察了再力花的汞富集效能,并对种植再力花的人工湿地进行除汞试验,分析其除汞能力的提升效果。结果表明:在3种浓度(50、100、200μg/L)的含汞水培营养液中,再力花均长势良好,对汞具有一定的富集作用;再力花对汞的吸收途径主要是从根系富集,占到了植物体总汞吸收量的50%以上;在3种浓度(50、100、200μg/L)的含汞进水下,湿地CW-1(种植再力花)对THg(总汞)、PHg(颗粒态汞)的去除主要发生在湿地的前1/4段,整体去除率分别为82.1%~87.3%、80.0%~89.5%,DHg(溶解态汞)浓度沿程均匀降低,去除率为81.1%~94.1%;与具有相同填料结构但无植物的湿地CW-2相比,湿地CW-1对THg、PHg和DHg的去除率分别提高了7.7%~8.8%、4.8%~6.0%、16.7%~19.3%。

Mercury in the environment can enter various ecosystems through sedimentation mechanism,and all kinds of water bodies are also threatened by mercury pollution due to human production activities.As a commonly used sewage treatment process,constructed wetlands have a good removal effect on heavy metals.In this study,based on the constructed wetland mercury removal efficiency,the mercury nutrient solution hydroponic experiments were carried out to investigate the mercury accumulation efficiency of the wetland plant——Thalia dealbata Fraser,and the mercury removal experiments of constructed wetland planted Thalia dealbata Fraser were carried out to analyze the improvement effect of mercury removal ability.The results showed that:in the three concentrations(50,100,200μg/L)of mercury containing hydroponic nutrient solution,Thalia dealbata Fraser grow well and has a certain enrichment effect on mercury;The absorption of mercury by Thalia dealbata Fraser is mainly enriched from the root system,accounting for more than 50%of the total absorption of the plant;In three concentrations(50,100,200μg/L)of mercury influent experiments,the removal of total mercury(THg)and particulate mercury(PHg)by constructed wetland with Thalia dealbata Fraser(CW-1)mainly occur in the first quarter of the wetland and the overall removal rates were 82.1%~87.3%and 80.0%~89.5%respectively.The concentration of dissolved mercury(DHg)decreases uniformly along the wetland,and the removal rates is 81.1%~94.1%;Compared with CW-2 with the same packing structure but without plants,the removal rates of THg,PHg and DHg by CW-1 were increase by 7.7%~8.8%,4.8%~6.0%and 16.7%~19.3%respectively.