利用氢基质生物膜反应器去除地下水中的Cr(Ⅵ)

Cr(Ⅵ) Reduction from Groundwater by Hydrogenbased Membrane Biofilm Reactor

摘要:

采用氢基质生物膜反应器(hydrogenbased membrane biofilm reactor,MBfR)生物去除地下水中的Cr(Ⅵ).MBfR膜表面氢自养还原菌利用氢气作为电子供体，进行自养还原反应，使水中Cr(Ⅵ)还原为Cr(Ⅲ)，形成沉淀而去除.通过培养生物膜、改变进水Cr(Ⅵ)质量浓度和氢分压，启动驯化120 d后Cr(Ⅵ)去除率达83%，NO-3N去除率高于99%.3种影响因素的试验研究表明：氢分压、NO-3N负荷和pH值对Cr(Ⅵ)的去除有影响.增加氢分压有利于Cr(Ⅵ)的去除；而NO-3N负荷的增加则导致Cr(Ⅵ)去除效率降低；Cr(Ⅵ)还原对pH值较为敏感，最佳pH值为7.0(最高去除率达78.2%)，pH值小于7.0或大于8.0时都会造成去除率显著降低.试验表明，利用氢基质生物膜反应器处理含Cr(Ⅵ)以及NO-3N和Cr(Ⅵ)污染共存的地下水体具有一定应用潜力，关键控制因素有氢分压、NO-3N质量浓度和pH值.

Abstract:

The hydrogenbased membrane biofilm reactor (MBfR) was used for biodegradation of Cr(Ⅵ) in groundwater.The autohydrogentrophic bacteria on the surface of membrane used hydrogen as electron donor to reduce Cr(Ⅵ) to Cr(Ⅲ).Then Cr(Ⅲ) was removed by sedimentation and filtration.The acclimatization was achieved by culturing the biofilm,altering the Cr(Ⅵ)concentration in influent and the supplied hydrogen pressure.After 120 days ,the Cr(Ⅵ) and NO-3N removal rate was 83% and 99%,respectively.Series experiments of 3 influence factors,such as H2 pressure,NO-3N loading and pH value were conducted.The results show that lowering the NO-3N loading and increasing the H2 pressure can increase the extent of Cr(Ⅵ) reduction.The Cr(Ⅵ) reduction is also sensitive to pH value,with the optimum pH value of 7.0(removal rate near 78.2%).If the pH value is above 8.0 or below 7.0,the removal rate will significantly decline.The research reveals that the MBfR can be effective for removing Cr(Ⅵ) or coexisting of NO-3N and Cr(Ⅵ) in groundwater,and critical operational parameters including the H2 pressure,NO-3N loading and pH value.