School of Environmental and Chemical Engineering, Shanghai University, 200444 Shanghai, PR China.
School of Environmental and Chemical Engineering, Shanghai University, 200444 Shanghai, PR China.
Sci Total Environ. 2022 Sep 10;838(Pt 1):155936. doi: 10.1016/j.scitotenv.2022.155936. Epub 2022 May 14.
Biological activated carbon (BAC) filtration is usually considered to be able to decrease formation potentials (FPs) of disinfection by-products (DBPs) in drinking water treatment plant (DWTP). However, BAC filters with long running time may release microbial metabolites to effluents and therefore increase FPs of nitrogenous DBPs with high toxicity. To verify this hypothesis, this study continuously tracked BAC filters in a DWTP for one year, and assessed effects of old (running time 8-9 years) and new (running time 0-13 months) BAC filters on FPs of 15 regulated and unregulated DBPs. Results revealed that dissolved organic carbon (DOC) removal was slightly higher in the new BAC than the old one. All fluorescent components of dissolved organic matter evidently declined after new BAC filtration, but fulvic acid-like and soluble microbial product-like substances increased after old BAC filtration, which could be caused by microbial leakage. Correspondingly, new BAC filter generally removed more DBP FPs than the old one. 46.5% HAA FPs from chlorination and 44.3% THM FPs from chloramination were removed by new BAC filter. However, some DBP FPs, especially HAN FPs, were poorly removed or even increased by the old BAC filter. Proteobacteria could be a main contributor for DBP precursor removal in BAC filters. Herminiimonas, most abundant genera in new BAC filter, may explain its better DOC and UV removal performance and lower DBP FPs, while Bradyrhizobium, most abundant genera in old BAC filter, might produce more extracellular polymeric substances and therefore increased N-DBP FPs in old BAC effluent. This study provided insight into variations of DBP FPs and microbial communities in the new and old BAC filters, and will be helpful for the optimization of DWTP design and operation for public health.
生物活性炭（BAC）过滤通常被认为能够降低饮用水处理厂（DWTP）中消毒副产物（DBP）的形成潜力（FP）。然而，运行时间较长的 BAC 过滤器可能会向流出物中释放微生物代谢物，从而增加具有高毒性的含氮 DBP 的 FP。为了验证这一假设，本研究在 DWTP 中连续监测 BAC 过滤器一年，并评估了旧（运行时间 8-9 年）和新（运行时间 0-13 个月）BAC 过滤器对 15 种受监管和不受监管的 DBP 的 FP 的影响。结果表明，新 BAC 的 DOC 去除率略高于旧 BAC。新 BAC 过滤后，所有溶解有机物的荧光成分明显下降，但腐殖酸样和可溶性微生物产物样物质在旧 BAC 过滤后增加，这可能是由微生物泄漏引起的。相应地，新 BAC 过滤器通常比旧 BAC 过滤器去除更多的 DBP FP。新 BAC 过滤器去除了氯化消毒的 46.5% HAA FP 和氯化消毒的 44.3% THM FP。然而，一些 DBP FP，特别是 HAN FP，被旧 BAC 过滤器去除效果较差或甚至增加。变形菌门可能是 BAC 过滤器中 DBP 前体去除的主要贡献者。新 BAC 过滤器中最丰富的属 Herminiimonas 可能解释了其更好的 DOC 和 UV 去除性能和较低的 DBP FP，而旧 BAC 过滤器中最丰富的属 Bradyrhizobium 可能产生更多的胞外聚合物物质，从而增加了旧 BAC 流出物中的 N-DBP FP。本研究深入了解了新老 BAC 过滤器中 DBP FP 和微生物群落的变化，将有助于优化 DWTP 设计和运行，以保障公众健康。
