以5种不同基质构建的模拟垂直流人工湿地对含铅废水的处理效果比较

Comparison of Treatment Efficiency for Wastewater with Pb^(2+) by Simulated Vertical Flow Constructed Wetlands with 5 Kinds of Substrates

将黄土、污泥、细沙、细煤渣、粉煤灰和砾石作为基质原料,取其中5种原料,以1∶1∶1∶1∶1的体积比,配置成不同原料混合而成的5种基质;在利用5种基质构建的模拟垂直流人工湿地中,处理Pb^(2+)质量浓度为10 mg/L、20mg/L、40 mg/L、80 mg/L和160 mg/L的废水(人工配制),控制水力停留时间为8 h。实验结果表明,当废水中Pb^(2+)质量浓度为10 mg/L、20 mg/L、40 mg/L和80 mg/L时,以污泥+黄土+细煤渣+砾石+细沙为基质构建的人工湿地对Pb^(2+)的去除率最高,为87.50%～93.77%;当废水中Pb^(2+)质量浓度为160 mg/L时,以粉煤灰+污泥+黄土+细煤渣+细沙为基质构建的人工湿地对Pb^(2+)的去除率最高,为91.00%;当废水中Pb^(2+)质量浓度为10 mg/L和20 mg/L时,在以粉煤灰+污泥+细煤渣+砾石+细沙为基质构建的人工湿地中,重金属的潜在迁移能力最弱;当废水中Pb^(2+)质量浓度为40 mg/L、80 mg/L和160 mg/L时,在以粉煤灰+污泥+黄土+细煤渣+细沙为基质构建的人工湿地中,重金属的潜在迁移能力最弱;基质的容重、有效粒径D10、不均匀系数K80、pH、阳离子交换量和有机质含量都与含铅废水的处理效果正相关,基质的总孔隙度、有效粒径D80、有效态锰和全量锰、镁、铝、铁含量则分别与Pb^(2+)的去除率、基质中的铅形态含量负相关。

Five kinds of substrates of constructed wetland were prepared with six materials (loess, sludge, fine sand, fine cinder, fly ash, gravel) according to 1:1:1:1:1 in volume ratio of five materials. The wastewater with Pb^2+ was treated by constructed wetlands with five kinds of substrates in 8 h hydraulic detention time. The wastewater with Pb' of 5 kinds of concentrations (10 mg/L, 20 mg/L, 40 mg/L, 80 mg/L, 160 mg/L) were made by artificial simulation. The results showed that the removal rates (87.50%-93.77%) of Pb^2+ was the highest by constructed wetland with substrate composed of sienna, sludge, fine sand, fine cinder and gravel when Pb^2+ concentrations were 10 mg/L, 20 mg/L, 40 mg/L and 80 mg/L in wastewater. The constructed wetland with substrate composed of sienna, sludge, fine sand, fine cinder and fly ash performed the best removal effects of 91.00% when Pb^2+ concentration was 160 mg/L in wastewater. The potential migration ability of Pb^2+ in wastewater was the lowest in the constructed wetland with substrate composed of fly ash, sludge, fine sand, fine cindcr and gravel when Pb^2+ concentrations were 10 mg/L and 20 mg/L in wastewater. The potential migration ability of Pb^2+t in wastewater was the lowest in the constnicted wetland with substrate composed of fly ash, sludge, loess, fine cinder and fine sand when Pb^2+ concentrations were 40 mg/L, 80 mg/L and 160 mg/L in wastewater. The stronger correlation appeared between removal efficiency and bulk density, specific gravity, effective grain size D10, pH, cation exchange capacity (CEC) and organic matter. Total porosity, nonunifbrmity coefficient K80, contents of active Mn and total Mn, Mg, Al, Fe perfbnned smaller correlation with chemical speciation and removal of Pb^2+ in waste water.