Department of Environmental Science & Engineering, Fudan University, Shanghai 200238, PR China.
Department of Environmental Science & Engineering, Fudan University, Shanghai 200238, PR China; Department of the Built Environment, Aalborg University, Aalborg 9220, Denmark.
Sci Total Environ. 2023 Jul 15;882:163589. doi: 10.1016/j.scitotenv.2023.163589. Epub 2023 Apr 20.
Algal organic matter (AOM) is considered to be threatening for the consumption of disinfectants and the formation of disinfection by-products (DBPs) during the disinfection process. Incompatible parameters in the conventional pretreatment of algal-laden water will lead to counterproductive results, such as AOM release. Therefore, the generation of AOM and its conversion to DBPs during pretreatment should be observed. The characteristics of DBPs from extracellular organic matter (EOM) and intracellular organic matter (IOM) were epitomized and simulation experiments were conducted in deionized (DI) water and source water under pretreatment conditions. Differences in DBP formation between the different backgrounds during chlorination and powdered activated carbon (PAC) treatment were investigated. Instead of monotonous excitation-emission matrix (EEM) spectra, molecular weight (MW) fractionation was simultaneously applied to elucidate the mechanisms of chlorination and PAC adsorption on AOM-based DBPs. The fluorescence regional integration (FRI) EEM results showed a clear correlation between the fluorescent properties and MW distribution of AOM. A decreasing trend was observed after a rapid increase in fluorescence intensity during the chlorination and PAC treatment of water samples in the simulation experiments in deionized (DI) water and source water. The DBP formation potential (FP) in the source water was consistent with the change in AOM during chlorination and PAC adsorption. In addition, EEM showed decent predictability of AOM-based trihalomethanes (THM) FPs (R = 0.77-0.99) invoking a combination with MW fractionation. Macromolecular protein compounds were highly correlated with the formation of dichloroacetonitrile (DCAN) (R = 0.89-0.98). These post-mortems results imply that EEM spectra are a useful tool for identifying AOM-based precursors to reveal the accurate environmental fate and risk assessments of AOM.
藻源有机物（AOM）被认为会对饮用水消毒产生威胁，并在消毒过程中形成消毒副产物（DBP）。藻类污染水中常规预处理的不兼容参数会导致适得其反的结果，例如 AOM 的释放。因此，应该观察预处理过程中 AOM 的产生及其向 DBP 的转化。总结了细胞外有机物（EOM）和细胞内有机物（IOM）中 DBP 的特征，并在预处理条件下的去离子（DI）水和原水中进行了模拟实验。研究了不同背景下氯化和粉末活性炭（PAC）处理过程中 DBP 形成的差异。除了单调的激发-发射矩阵（EEM）光谱外，还同时应用分子量（MW）分级来阐明基于 AOM 的 DBP 的氯化和 PAC 吸附机制。荧光区域积分（FRI）EEM 结果表明，AOM 的荧光特性和 MW 分布之间存在明显的相关性。在 DI 水和原水中的模拟实验中，水样在氯化和 PAC 处理过程中，荧光强度迅速增加后，出现了荧光强度的下降趋势。原水中的 DBP 形成潜力（FP）与氯化和 PAC 吸附过程中 AOM 的变化一致。此外，EEM 显示出与基于 AOM 的三卤甲烷（THM）FP 相当好的预测能力（R=0.77-0.99），这是通过与 MW 分级相结合实现的。大分子蛋白质化合物与二氯乙腈（DCAN）的形成高度相关（R=0.89-0.98）。这些事后分析结果表明，EEM 光谱是一种有用的工具，可以识别基于 AOM 的前体物质，以揭示 AOM 的准确环境归宿和风险评估。
