Department of Environmental Science & Engineering, Fudan University, Shanghai 200238, China.
Department of Environmental Science & Engineering, Fudan University, Shanghai 200238, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
Water Res. 2020 Nov 1;186:116346. doi: 10.1016/j.watres.2020.116346. Epub 2020 Aug 23.
Haloacetonitriles (HANs) and haloacetamides (HAMs) are nitrogenous disinfection byproducts that are present in filter backwash water (FBW) and sedimentation sludge water (SSW). In many cases FBW and SSW are recycled to the head of drinking water treatment plants. HAN and HAM concentrations in FBW and SSW, without additional oxidants, ranged from 6.8 to 11.6 nM and 2.9 to 3.6 nM of three HANs and four HAMs, respectively. Upon oxidant addition to FBW and SSW under formation potential conditions, concentrations for six HANs and six HAMs ranged from 92.2 to 190.4 nM and 42.2 to 95.5 nM, respectively. Therefore, at common FBW and SSW recycle rates (2 to 10% of treated water flows), the precursor levels in these recycle waters should not be ignored because they are comparable to levels present in finished water. Brominated HAN and chlorinated HAM were the dominant species in FBW and SSW, respectively. The lowest molecular weight ultrafiltration fraction (< 3 kDa) contributed the most to HAN and HAM formations. The hydrophilic (HPI) organic fraction contributed the greatest to HAN precursors in sand-FBW and SSW and were the most reactive HAM precursors in both sand- or carbon-FBWs. Fluorescence revealed that aromatic protein-like compounds were dominant HAN and HAM precursors. Therefore, strategies that remove low molecular weight hydrophilic organic matter and aromatic protein-like compounds will minimize HAN and HAM formations in recycled FBW and SSW.
卤乙腈（HANs）和卤乙酰胺（HAMs）是含氮消毒副产物，存在于滤池反冲洗水（FBW）和沉淀污泥水中（SSW）中。在许多情况下，FBW 和 SSW 会被回收至饮用水处理厂的前端。在没有额外氧化剂的情况下，FBW 和 SSW 中的 HAN 和 HAM 浓度分别为 6.8 至 11.6 nM 和 2.9 至 3.6 nM 的三种 HAN 和四种 HAMs。当在形成潜力条件下向 FBW 和 SSW 添加氧化剂时，六种 HAN 和六种 HAMs 的浓度范围分别为 92.2 至 190.4 nM 和 42.2 至 95.5 nM。因此，在常见的 FBW 和 SSW 回收率（处理水流量的 2%至 10%）下，这些回用水中的前体水平不应被忽视，因为它们与成品水中的水平相当。在 FBW 和 SSW 中，溴代 HAN 和氯代 HAM 分别是主要的物种。最低分子量超滤部分（<3 kDa）对 HAN 和 HAM 的形成贡献最大。亲水性（HPI）有机部分在砂滤池 FBW 和 SSW 中对 HAN 前体的贡献最大，在砂或碳滤池 FBW 中对 HAM 前体的反应性最大。荧光表明，芳香蛋白样化合物是 HAN 和 HAM 的主要前体。因此，去除低分子量亲水性有机物和芳香蛋白样化合物的策略将最大限度地减少回收 FBW 和 SSW 中的 HAN 和 HAM 的形成。
