State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Ministry of Education Key Laboratory of Yangtze River Water Environment, Tongji University, Shanghai 200092, China; International Joint Research Center for Sustainable Urban Water System, Tongji University, Shanghai 200092, China.
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
J Hazard Mater. 2021 Oct 15;420:126558. doi: 10.1016/j.jhazmat.2021.126558. Epub 2021 Jul 3.
Coagulation is well-established for controlling regulated disinfection by-products (DBPs), but its effectiveness for controlling unregulated DBPs remains unclear. The efficiency of coagulation in controlling unregulated DBPs requires clarification owing to their relatively high toxicity. In this study, three Al-based coagulants, aluminum sulfate (Alum), polyaluminum chloride (PAC), and a novel type of covalently bond hybrid coagulant (CBC, synthesized using AlCl) were selected, and the coagulation performance of these Al-based coagulants in controlling DBPs and DBP-associated toxicity was compared over 5 classes of DBPs, including trihalomethanes, haloacetic acids, haloacetaldehydes, haloacetonitriles, and halonitromethanes. The results showed that Alum was the least efficient in removing DBP precursors among the three coagulants. The effectiveness of CBC and PAC for DBP control varied with the characteristics of source waters. CBC had an advantage in water with a low content of humic acids, and reduced DBP concentration and DBP-associated toxicity by 47% and 25%, respectively. For water rich in aromatic organics, CBC might serve as DBP precursors at a high-required dosage, suggesting that a trade-off between enhanced DBP control and serving as DBP precursors should be considered for CBC coagulation; PAC achieved the most reduction in DBP concentration and DBP-associated toxicity by 50% and 34%, respectively.
混凝沉淀被广泛用于控制有规消毒副产物（DBPs），但其对无规 DBPs 的控制效果尚不清楚。鉴于无规 DBPs 的毒性相对较高，其需要通过混凝沉淀进行控制，因此需要明确混凝沉淀的控制效率。本研究选取了 3 种铝基混凝剂：硫酸铝（Alum）、聚合氯化铝（PAC）和一种新型共价键合的混合混凝剂（CBC，使用 AlCl3 合成），并对这 3 种铝基混凝剂在控制 5 类 DBPs（三卤甲烷、卤乙酸、卤代醛、卤代乙腈和卤代硝基甲烷）及其相关毒性方面的性能进行了比较。结果表明，在 3 种混凝剂中，Alum 去除 DBP 前体的效率最低。CBC 和 PAC 对 DBP 的控制效果因原水特性而异。CBC 在低腐殖酸含量的水中具有优势，分别可将 DBP 浓度和 DBP 相关毒性降低 47%和 25%。对于富含芳香有机物的水，CBC 可能会作为 DBP 前体在高需求剂量下发挥作用，这表明在考虑使用 CBC 混凝沉淀进行 DBP 控制时，应权衡增强 DBP 控制和充当 DBP 前体之间的关系；PAC 可将 DBP 浓度和 DBP 相关毒性分别降低 50%和 34%。
