The effect of hydraulic retention time (HRT) and pH on the biooxidation of ferrous iron during simulated acid mine drainage (AMD) treatment was investigated.The simulated AMD was highly acidic (pH 2.5), rich in iron (...The effect of hydraulic retention time (HRT) and pH on the biooxidation of ferrous iron during simulated acid mine drainage (AMD) treatment was investigated.The simulated AMD was highly acidic (pH 2.5), rich in iron (about 1700 mg/L) and copper (about 200 mg/L), and contained high concentrations of sulfate (about 4700 mg/L).The biooxidation of ferrous iron was studied in a laboratory-scale upflow packed bed bioreactor (PBR).The HRT was shortened stepwise from 40 h to 20 h, 13 h, and 8 h under the acidic environment at a pH value of 2.2.Then, the influent pH value was changed from 2.2 to 1.2 at a constant suitable HRT.Physiochemical and microbial community structure analyses were performed on water samples and stuffing collected from the bioreactor under different conditions.The results indicate that the efficiency of ferrous iron oxidation gradually decreased with the decrease of HRT, and when the HRT exceeded 13 h, ferrous iron in AMD was almost completely oxidized.In addition, the best efficiency of ferrous iron oxidation was achieved at the influent pH value of 1.8.Microbial community structure analyses show that Leptospirillum is the predominant genus attached in the bioreactor, and low influent pH values are suitable for the growth of Leptospirillum.展开更多
以芦苇为湿地植物构建微生物燃料电池-人工湿地耦合系统(MFC-CW),研究进水COD、水力停留时间(HRT)及阴极曝气量对MFC-CW产电和污水净化性能的影响。结果表明:MFC-CW系统经驯化后能够稳定运行,在净化污水的同时产电。随着进水COD的增大,M...以芦苇为湿地植物构建微生物燃料电池-人工湿地耦合系统(MFC-CW),研究进水COD、水力停留时间(HRT)及阴极曝气量对MFC-CW产电和污水净化性能的影响。结果表明:MFC-CW系统经驯化后能够稳定运行,在净化污水的同时产电。随着进水COD的增大,MFC-CW系统的输出电压及COD去除率均先增大后减小,在COD为200 mg/L时系统产电量最大,为294 m V;COD为300 mg/L时系统COD去除率最大,为89.4%。随着HRT的增大,系统输出电压先增大后减小,在HRT为3 d时达到最大,为280 m V;系统COD去除率先增大后趋于平稳,HRT为3 d时去除率最高,为86%。系统输出电压及COD去除率随阴极曝气量的增大而增大,但其增长的速率逐渐减小。选择最适阴极曝气量时需要综合考虑输出电压、污水净化效果及经济成本。综合考虑各因素,优选0.075 m^3/h为最佳曝气量。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.U1402234)the Guangxi Scientific Research and Technology Development Plan(Grants No.GuikeAB16380287 and GuikeAB17129025)+2 种基金the Public Welfare Fund of the Ministry of Environmental Protection of China(Grant No.201509049)the Program of International S & T Cooperation(Grant No.2016YFE0130700)the Fund of the General Research Institute for Nonferrous Metals(Grants No.53321 and 53348)
文摘The effect of hydraulic retention time (HRT) and pH on the biooxidation of ferrous iron during simulated acid mine drainage (AMD) treatment was investigated.The simulated AMD was highly acidic (pH 2.5), rich in iron (about 1700 mg/L) and copper (about 200 mg/L), and contained high concentrations of sulfate (about 4700 mg/L).The biooxidation of ferrous iron was studied in a laboratory-scale upflow packed bed bioreactor (PBR).The HRT was shortened stepwise from 40 h to 20 h, 13 h, and 8 h under the acidic environment at a pH value of 2.2.Then, the influent pH value was changed from 2.2 to 1.2 at a constant suitable HRT.Physiochemical and microbial community structure analyses were performed on water samples and stuffing collected from the bioreactor under different conditions.The results indicate that the efficiency of ferrous iron oxidation gradually decreased with the decrease of HRT, and when the HRT exceeded 13 h, ferrous iron in AMD was almost completely oxidized.In addition, the best efficiency of ferrous iron oxidation was achieved at the influent pH value of 1.8.Microbial community structure analyses show that Leptospirillum is the predominant genus attached in the bioreactor, and low influent pH values are suitable for the growth of Leptospirillum.
文摘以芦苇为湿地植物构建微生物燃料电池-人工湿地耦合系统(MFC-CW),研究进水COD、水力停留时间(HRT)及阴极曝气量对MFC-CW产电和污水净化性能的影响。结果表明:MFC-CW系统经驯化后能够稳定运行,在净化污水的同时产电。随着进水COD的增大,MFC-CW系统的输出电压及COD去除率均先增大后减小,在COD为200 mg/L时系统产电量最大,为294 m V;COD为300 mg/L时系统COD去除率最大,为89.4%。随着HRT的增大,系统输出电压先增大后减小,在HRT为3 d时达到最大,为280 m V;系统COD去除率先增大后趋于平稳,HRT为3 d时去除率最高,为86%。系统输出电压及COD去除率随阴极曝气量的增大而增大,但其增长的速率逐渐减小。选择最适阴极曝气量时需要综合考虑输出电压、污水净化效果及经济成本。综合考虑各因素,优选0.075 m^3/h为最佳曝气量。
