Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore.
Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore.
Sci Total Environ. 2024 Apr 20;922:171317. doi: 10.1016/j.scitotenv.2024.171317. Epub 2024 Feb 28.
Sequential utilization of ozone (O) and biological activated carbon (BAC) followed by UV/chlor(am)ine advanced oxidation process (AOP) has drawn attention in water reuse. However, the formation of disinfection by-products (DBPs) in this process is less evaluated. This study investigated the DBP formation and the relevant toxicity during the O-BAC-UV/chlor(am)ine treatment of sand-filtered municipal secondary effluent. DBP formation in UV/chlorine and UV/dichloramine (NHCl) processes were compared, where the impact of key operational parameters (e.g., UV wavelength, pH) on DBP formation were comprehensively evaluated. O-BAC significantly reduced DBP formation potential (DBPFP) (58.2 %). Compared to UV/chlorine AOP, UV/NHCl AOP reduced DBP formation by 29.7 % in short-time treatment, while insignificantly impacting on DBPFP (p > 0.05). UV/NHCl AOP also led to lower calculated cytotoxicity (67.7 %) and genotoxicity (55.9 %) of DBPs compared to UV/chlorine AOP. Compared to 254 nm UV light, the utilization of 285 nm UV light decreased the formation of DBPs in wastewater treated with the UV/chlorine AOP and UV/NHCl AOP by 31.3 % and 19.2 %, respectively. However, the cytotoxicity and genotoxicity in UV/NHCl AOP using 285 nm UV light increased by 83.4 % and 58.5 %, respectively, compared to 254 nm. The concentration of DBPs formed in the UV/NHCl AOP at pH 8 was 54.3 % lower than that at pH 7, suggesting a better control of DBPs at alkaline condition. In the presence of bromide, UV/NHCl AOP tended to generate more brominated DBPs than UV/chlorine AOP. Overall, UV/NHCl AOP resulted in lower concentration and toxicity of DBPs compared to UV/chlorine AOP.
臭氧（O）和生物活性炭（BAC）的顺序利用，随后是紫外线/氯化（胺）高级氧化工艺（AOP），在水再利用中引起了关注。然而，该过程中消毒副产物（DBP）的形成较少被评估。本研究调查了砂滤市政二级出水经 O-BAC-UV/氯化（胺）处理过程中的 DBP 形成和相关毒性。比较了 UV/氯和 UV/二氯化胺（NHCl）工艺中的 DBP 形成，全面评估了关键操作参数（例如，UV 波长，pH 值）对 DBP 形成的影响。O-BAC 可显著降低 DBP 形成潜力（DBPFP）（58.2%）。与 UV/氯 AOP 相比，UV/NHCl AOP 在短时间处理中可减少 29.7%的 DBP 形成，但对 DBPFP 无明显影响（p>0.05）。与 UV/氯 AOP 相比，UV/NHCl AOP 还导致处理废水中的 DBPs 的计算细胞毒性（67.7%）和遗传毒性（55.9%）降低。与 254nm UV 光相比，在 UV/氯 AOP 和 UV/NHCl AOP 处理的废水中，利用 285nm UV 光可分别减少 31.3%和 19.2%的 DBP 形成。然而，与 254nm 相比，在使用 285nm UV 光的 UV/NHCl AOP 中，细胞毒性和遗传毒性分别增加了 83.4%和 58.5%。在 pH 8 时，UV/NHCl AOP 中形成的 DBP 浓度比在 pH 7 时低 54.3%，表明在碱性条件下可以更好地控制 DBP。在存在溴化物的情况下，UV/NHCl AOP 倾向于比 UV/氯 AOP 产生更多的溴化 DBP。总体而言，与 UV/氯 AOP 相比，UV/NHCl AOP 产生的 DBP 浓度和毒性较低。
