Environmental Engineering Program, University of Colorado Boulder, 428 UCB, Boulder, Colorado 80309, United States.
Environ Sci Technol. 2023 Feb 14;57(6):2516-2526. doi: 10.1021/acs.est.2c05504. Epub 2023 Feb 1.
Disinfection byproduct (DBP) pre-formation is a major issue when prechlorination is used before or during advanced treatment of impacted drinking water sources. Control strategies for pre-formed DBPs before final disinfection, especially for currently nonregulated although highly toxic DBP species, are not yet established. This study evaluated the biodegradation potential of pre-formed DBPs, including haloacetonitriles (HANs), haloacetamides (HAMs), and haloacetaldehydes (HALs), during biofiltration with sand, anthracite, and biological activated carbon of three wastewater effluents under potable reuse conditions. Up to 90%+ removal of di- and trihalogenated HANs, HAMs, and HALs was observed, and removal was associated with active heterotrophic biomass and removal of biodegradable organic carbon. Unlike the microbial dehalogenation pathway of haloacetic acids (HAAs), removal of HANs and HAMs appeared to result from a biologically mediated hydrolysis pathway (i.e., HANs to HAMs and HAAs) that may be prone to inhibition. After prechlorination, biofiltration effectively controlled pre-formed DBP concentrations (e.g., from 271 μg/L to as low as 22 μg/L in total) and DBP-associated calculated toxicity (e.g., 96%+ reduction). Abiotic residual adsorption capacity in biological activated carbon media was important for controlling trihalomethanes. Overall, the toxicity-driving DBP species exhibited high biodegradation potential and biofiltration showed significant promise as a pre-formed DBP control technology.
消毒副产物（DBP）的形成前体是在受污染的饮用水源进行高级处理之前或期间进行预氯化时的一个主要问题。对于最终消毒之前的形成前体 DBP 的控制策略，特别是对于目前虽然毒性高但尚未受到管制的 DBP 种类，尚未建立。本研究评估了在三种废水处理厂污水回用时条件下，通过砂、无烟煤和生物活性炭的生物过滤，形成前体 DBP（包括卤乙腈（HANs）、卤乙酰胺（HAMs）和卤乙醛（HALs））的生物降解潜力。观察到二卤代和三卤代 HANs、HAMs 和 HALs 的去除率高达 90%+，去除与活性异养生物量和可生物降解有机碳的去除有关。与卤乙酸（HAAs）的微生物脱卤途径不同，HANs 和 HAMs 的去除似乎是由于生物介导的水解途径（即 HANs 到 HAMs 和 HAAs），该途径可能容易受到抑制。预氯化后，生物过滤有效地控制了形成前体 DBP 的浓度（例如，总浓度从 271μg/L 降低至低至 22μg/L）和 DBP 相关的计算毒性（例如，减少 96%+）。生物活性炭介质中的非生物残留吸附容量对于控制三卤甲烷很重要。总的来说，毒性驱动的 DBP 种类表现出很高的生物降解潜力，生物过滤作为一种形成前体 DBP 控制技术具有很大的应用前景。
