植物-基质人工湿地系统净化Zn残留废水的实验研究

Experimental Study on Zn Residue Wastewater Purification by Plant-substrate Constructed Wetland System

为探寻植物-基质湿地系统去除废水中Zn的优化组合,构造粉煤灰(H)、河沙(S)及混合基质(S+H)与灯芯草(Juncus effusus)、水芹菜(Oenanthe javanica)和水葫芦(Eichhornia crassipes)组成的人工湿地系统.考察Zn浓度100 mg·L^-1的废水,流经不同基质人工湿地系统后Zn的去除效果.结果表明:不同基质系统对Zn去除率均高于95%,有植物系统对Zn的去除效果显著好于无植物系统,有植物的S+H基质对Zn的去除率高达98.82%,出水水质稳定,植物生长良好,但出水pH较高;水芹菜、灯芯草、水葫芦均能对Zn进行高效富集,水葫芦的富集能力最强,灯芯草的抗逆性最好,且向地上部分迁移Zn的能力最强;三种植物在相对偏碱性的条件下对Zn的吸收效果更好.综合评估,有植物的S+H基质是本实验中最佳的模拟除Zn湿地系统.以上研究结果为除Zn人工湿地的构建提供选材参考.

In order to explore the optimal combination of plant-substrate constructed wetland system for removing Zn from wastewater,an constructed wetlands with different substrates(fly ash(H),river sand(S)and their mixture(S+H)),planting with Juncus effusus,Oenanthe javanica and Eichhornia crassipes was constructed to explore the removal effect of different matrix systems on wastewater containing 100 mg·L^-1 Zn.The results showed that the Zn removal rates in different substrate systems were higher than 95%,in which Zn removal rate of planted systems was significantly higher than that of unplanted systems,Zn removal rates of mixed substrate with plants can reach 98.82%.The quality of influent was stable and the plants grew well,but the pH of influent was too high.Juncus effusus,Oenanthe javanica and Eichhornia crassipes could effectively absorb Zn,among which Eichhornia crassipes had the strongest ability to absorb Zn,Juncus effusus had the strongest ability to resist Zn stress,and had the strongest ability to transfer Zn to the above ground parts.These three kind of plants had a better absorption effect on Zn under relatively alkaline conditions.By the comprehensive evaluation,it could be concluded that the mixed substrate with plants is the best simulated Zn removal constructed wetland in this experiment.The above research results can provide material selection reference for the construction of Zn-removed constructed wetlands.