Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Institute of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450045, China.
Water Res. 2022 Jun 30;218:118495. doi: 10.1016/j.watres.2022.118495. Epub 2022 Apr 23.
Granular activated carbon (GAC) filtration impacts pathogen colonization and bacterial communities in drinking water. However, the effects of ozone and heterogeneous Fenton oxidation on microbial community composition, in particular opportunistic pathogens (OPs), and their metabolic potential in biofilms and effluents from GAC filtration are not fully understood. The results of our pilot-scale test indicated that Fenton-GAC filtration removed more dissolved organic carbon (DOC, 1.25 mg/L) than ozone-GAC filtration (0.98 mg/L). Excitation-emission matrix (EEM) results showed that Fenton-GAC removed more tyrosine-like proteins and fulvic acid-like materials, while ozone-GAC removed more humic acid-like compounds and tryptophan-like proteins. Illumina HiSeq analysis indicated that Curvibacter and Hydrogenophaga dominated in the Fenton-GAC biofilm, while Bradyrhizobium, Aquabacterium and Limnobacter were predominant in the ozone-GAC biofilm. Functional prediction suggested that the microbial functional gene related to glyoxylate and dicarboxylate metabolism (the pathway for carbohydrate metabolism) was higher in the Fenton-GAC biofilm, resulting in higher contents of protein in extracellular polymeric substances (EPS) in the Fenton-GAC biofilm. Therefore, there were fewer bacteria that detached from the biofilm into the water during the Fenton-GAC filtration process. The lower EPS content in the effluents from Fenton-GAC resulted in bacteria, including OPs, being easier to remove by chlorine. However, ozone oxidation removed more bacteria, including different OPs, than Fenton oxidation, which contributed to fewer bacteria and OPs in the effluents from ozone-GAC. Overall, our results provide a Fenton-GAC treatment process to remove DOC and control OPs in drinking water systems, the cost of which was comparable to that of ozone-GAC.
颗粒活性炭 (GAC) 过滤会影响饮用水中的病原体定殖和细菌群落。然而，臭氧和非均相芬顿氧化对微生物群落组成的影响，特别是机会性病原体 (OPs)，以及它们在生物膜和 GAC 过滤流出物中的代谢潜力，尚未完全了解。我们的中试结果表明，芬顿-GAC 过滤比臭氧-GAC 过滤去除更多的溶解有机碳 (DOC，1.25 mg/L) (0.98 mg/L)。激发发射矩阵 (EEM) 结果表明，芬顿-GAC 去除了更多的酪氨酸样蛋白和富里酸样物质，而臭氧-GAC 去除了更多的腐殖酸样化合物和色氨酸样蛋白。Illumina HiSeq 分析表明，在芬顿-GAC 生物膜中，弯曲杆菌属和噬氢菌属占主导地位，而在臭氧-GAC 生物膜中，缓生根瘤菌属、Aquabacterium 和 Limnobacter 占主导地位。功能预测表明，与乙醛酸和二羧酸代谢（碳水化合物代谢途径）相关的微生物功能基因在芬顿-GAC 生物膜中较高，导致芬顿-GAC 生物膜中细胞外聚合物 (EPS) 中的蛋白质含量较高。因此，在芬顿-GAC 过滤过程中，从生物膜中脱落到水中的细菌较少。芬顿-GAC 流出物中的 EPS 含量较低，导致包括 OPs 在内的细菌更容易被氯去除。然而，与芬顿氧化相比，臭氧氧化去除了更多的细菌，包括不同的 OPs，这有助于减少臭氧-GAC 流出物中的细菌和 OPs。总的来说，我们的结果提供了一种芬顿-GAC 处理工艺，用于去除饮用水系统中的 DOC 和控制 OPs，其成本与臭氧-GAC 相当。
