臭氧-接种生物滤池组合工艺去除饮用水中典型致嗅物质

通过在生物滤池表面接种MIB(2-甲基异茨醇)及geosmin(土臭素)降解菌,增强生物滤池的作用,并探讨臭氧-生物滤池组合工艺对MIB和geosmin的处理效果. 结果表明:单独接种生物滤池可使ρ(MIB)和ρ(geosmin)从初始的500ng/L分别降至125和112ng/L,MIB和geosmin的去除效果先随EBCT(空床停留时间)的延长而显著增加,但当EBCT大于20min后无明显变化；随着滤料深度的增加,滤池生物量逐渐降低,对污染物的去除率增加缓慢.在接种生物滤池前增加臭氧单元,当EBCT为20min、臭氧投加量为2mg/L时,臭氧-接种生物滤池组合工艺可去除84%的MIB和94%的geosmin,其中接种生物滤池单元中生物量随滤池深度的增加呈先增后减的趋势,滤料深度为100~200mm时,单位高度滤料的去除率最高. 采用臭氧-接种生物滤池组合工艺可有效去除水中的MIB和geosmin. 

Ozonation-Inoculated Biofiltration for Removal of the Typical Taste and Odor Compounds in Drinking Water

methylisoborneol (MIB) and geosmin are two of the most common taste and odor compounds which can not be readily removed by conventional drinking water treatment processes. The objective of this study was to enhance the biofiltration of MIB and geosmin by inoculating the sand filter with MIB and geosmin degraders, and to examine the removal efficiencies of MIB and geosmin using inoculated filter and non-inoculated filter in the presence and absence of ozonation. The degraders were Micrococcus sp., Flavobacterium sp., Brevibacterium sp. and Pseudomonas sp. as MIB degraders, and Chryseobacterium sp., Sinorhizobium sp., and Stenotrophomonas sp. as geosmin degraders. These bacteria were isolated from granular activated carbon in a commercial water plant. For the filter inoculated with a consortium of MIB and geosmin biodegraders, MIB and geosmin contents were decreased to 125and 112ng/L from 500ng/L, respectively. Initially, removal efficiencies of MIB and geosmin rapidly increased with the extension of empty bed contact time (EBCT), and resulted in no obvious change when EBCT was over than 20min. The biomass decreased rapidly along down the depth of the filter, resulting in the decrease of MIB and geosmin removal rate. Ozone was added to increase the removal efficiency since MIB and geosmin contents can’t be reduced to the acceptable range by inoculated biofiltration. Removal efficiencies of MIB and geosmin for the ozone-inoculated biofilter were 84% and 94% at the stage of 20min when ozone of 2mg/L was injected prior to biofiltration. The biomass on the surface of the filter media increased first, and then decreased along down the depth of the filter. The maximum removal efficiency mainly took place at the depth between 100and 200mm. Ozonation-inoculated biofiltration is an attractive option for MIB and geosmin removal.