负载AsOB离子交换纤维FFA⁃1去除水中三价砷

Removal of trivalent arsenic in water by ion exchange fiber FFA⁃1 loaded with AsOB

对比两组填充了离子交换纤维FFA⁃1的固定床反应器(R1和R2)的运行处理效果,研究负载功能微生物的离子纤维组合工艺对不同浓度As(Ⅲ)的去除能力.研究结果表明接种了三价砷氧化菌(AsOB)的R1能够长期稳定并高效地去除不同浓度(1~10 mg·L^-1)As(Ⅲ).未接种AsOB的R2反应器初期无法去除As(Ⅲ),随着微生物逐步侵入R2反应器,7 d后R2反应器As(Ⅲ)去除率逐渐与R1接近.相对于一直稳定运行的R1反应器,每次提升进水中As(Ⅲ)浓度后R2去除率呈现先下降后上升的趋势.同时,在运行过程中发现进水中NO3^-和SO4^2-等阴离子也会被R1和R2去除从而导致As(Ⅲ)去除总量的下降.离子交换纤维FFA⁃1再生实验证实R1和R2中的纤维与原始的离子交换纤维FFA⁃1再生效果相当(再生率均达到90%以上).进一步研究微生物种群结构在反应器中的变化发现离子交换纤维作为微生物载体可能是影响微生物种群结构的重要因素.本研究证实了功能微生物AsOB联合离子交换纤维可以作为一种高效去除地下水中三价砷的工艺,具有很好的应用前景.

The removal efficiency of As(Ⅲ)at different concentrations by the arsenite⁃oxidizing bacteria(AsOB)combined with ion fiber process was studied by comparing the performances of two fixed bed reactors(R1 and R2)filled with ion-exchange fiber FFA⁃1 with(or without)inoculation of AsOB.R1 inoculated with AsOB microorganism can stably and efficiently remove As(Ⅲ)at different concentrations(1~10 mg·L^-1)for a long time.At the beginning of the stage,As(Ⅲ)could not be removed in R2 without the inoculation of AsOB.With the invasion of microorganisms in R2,the As(Ⅲ)removal efficiency was gradually increased and close to that in R1 after 7 days of operation.Once the concentration of As(Ⅲ)in the influent increased,the tendency of removal efficiency in R2 was firstly decreased and then increased.During the operation,it was found that anions such as NO3^- and SO4^2-in the water were also removed,resulting in a decrease of the total amount of As(Ⅲ)removal.The fiber regeneration experiments confirmed that the regeneration ratios of fibers utilized in R1 and R2 were always the same as that of the original ion fiber(the regeneration ratio reached over 90%).Furthermore,the variation of microbial population structure in R1 and R2 revealed that ion fiber as a microbial carrier may be an important factor affecting the microbial population structure.Therefore,the combined process including the ion exchange fiber inoculated with AsOB can be used as a highly efficient process to remove arsenite from groundwater.