Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China.
Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China.
Chemosphere. 2018 Oct;209:68-77. doi: 10.1016/j.chemosphere.2018.06.018. Epub 2018 Jun 12.
The O/BAC process has been widely used in drinking water treatment to improve the removal of dissolved organic matters (DOMs), including the precursors of nitrogenous disinfection byproducts (N-DBPs). In this study, the removal of N-DBP precursors by biological activated carbon (BAC) filters with different usage time of granular activated carbon (GAC) was investigated. Results showed that the BAC filter with 6 years of usage time of GAC (old BAC filter) had a poor performance in the removal of precursors of N-DBPs such as dichloroacetonitrile (DCAN; an average of only 4.7%), dichloroacetamide (DCAcAm), and trichloronitromethane (TCNM) when compared with the BAC filter with 1 year of usage time of GAC (new BAC filter). Particularly, the organic fraction >10 kDa and the percentage of autochthonous substances were increased in the effluent of the old BAC filter. The red shift of the fluorescence peaks was evident in the excitation-emission matrix spectrum of the effluent from the old BAC filter. The abiotic adsorption of precursors by the old BAC filter was less. In addition, less amino acids and polysaccharides were removed, but more amino sugars and proteins were produced because of microbial metabolism. The metabolism strength of the attached biofilm decreased with increased operation time of the BAC filter. The relative abundance of Sphingomonas significantly decreased in the biofilm of the old BAC filter. The diversity of microbial community in the old BAC filter was higher, but the equitability was lower than those of the new BAC filter. The less removal of N-DBP precursors by the old BAC filter was attributed to the changes in abiotic adsorption capacity and microbial metabolism properties, in which soluble microbial products played an important role.
O/BAC 工艺已广泛应用于饮用水处理中，以提高对溶解有机物（DOM）的去除率，包括含氮消毒副产物（N-DBPs）的前体物。本研究考察了不同活性炭使用时间的生物活性炭（BAC）滤池对 N-DBP 前体物的去除效果。结果表明，与使用 1 年的 GAC 的 BAC 滤池（新 BAC 滤池）相比，使用 6 年的 GAC 的 BAC 滤池（旧 BAC 滤池）对 N-DBP 前体物（如二氯乙腈（DCAN；平均仅为 4.7%）、二氯乙酰胺（DCAcAm）和三氯硝基甲烷（TCNM））的去除效果较差。特别是，旧 BAC 滤池出水中大于 10 kDa 的有机部分和土著物质的比例增加。旧 BAC 滤池出水中的荧光激发-发射矩阵光谱明显出现红移。与新 BAC 滤池相比，旧 BAC 滤池对前体物的非生物吸附较少。此外，由于微生物代谢，旧 BAC 滤池的氨基酸和多糖去除减少，但更多的氨基糖和蛋白质生成。随着 BAC 滤池运行时间的增加，附着生物膜的代谢强度降低。旧 BAC 滤池生物膜中的鞘氨醇单胞菌相对丰度显著降低。旧 BAC 滤池的微生物群落多样性较高，但均匀度较低，与新 BAC 滤池相比。旧 BAC 滤池对 N-DBP 前体物的去除效果较差，这归因于非生物吸附能力和微生物代谢特性的变化，其中可溶性微生物产物发挥了重要作用。
