程冬馨,司杰,钟转有,黄璜.供水管网生物膜有机物的二氯乙腈与二氯乙酰胺生成特性[J].环境科学学报,2020,40(2):497-503
供水管网生物膜有机物的二氯乙腈与二氯乙酰胺生成特性
- Formation of dichloroacetonitrile and dichloroacetamide from biofilms in drinking water distribution systems
- 基金项目：广州市科技计划项目（No.201904010125）；国家自然科学基金青年科学基金项目（No.51408619）
- 程冬馨
- 中山大学环境科学与工程学院, 广东省环境污染控制与修复技术重点实验室, 广州 510006
- 司杰
- 中山大学环境科学与工程学院, 广东省环境污染控制与修复技术重点实验室, 广州 510006
- 钟转有
- 中山大学环境科学与工程学院, 广东省环境污染控制与修复技术重点实验室, 广州 510006
- 黄璜
- 中山大学环境科学与工程学院, 广东省环境污染控制与修复技术重点实验室, 广州 510006
- 摘要：在饮用水输配系统中，来源于管壁生物膜的有机物可能耗氯并生成消毒副产物（DBPs），包括二氯乙腈（DCAN）与二氯乙酰胺（DCAcAm）等高毒性含氮DBPs（N-DBPs）.研究考察管网常见的细菌与其胞外聚合物（EPS）以及模拟管壁生物膜氯化与氯胺化后DCAN与DCAcAm的生成，并与天然有机物（NOM）和水源水有机物进行比较.结果显示，铜绿假单胞菌、恶臭假单胞菌与藤黄微球菌与氯反应生成的DCAN、DCAcAm浓度分别为1.48~2.02、0.21~0.38 μg·mg-1（mg-1以TOC计），高于同反应条件下NOM的生成量；相比于氯化反应，3株细菌细胞氯胺化生成的DCAN与DCAcAm浓度明显更低.3株菌的EPS也是氯与氯胺化反应生成DCAN与DCAcAm的前体物，且其氯胺化反应生成的DCAcAm浓度高于氯化反应生成的.与NOM、水源水相比，模拟管壁生物膜氯化后生成的N-DBPs与三氯甲烷（TCM）浓度比更高，表明生物膜有机物比NOM与水源水有机物更倾向生成DCAN与DCAcAm类N-DBPs，且模拟管壁生物膜氯胺化的DCAcAm生成量高于氯化反应的，说明管壁生物膜有机物是供水管网系统中DCAN与DCAcAm类N-DBPs的重要前体物.
- Abstract：Given the regulatory presence of residual chlorine or chloramines in water distribution systems, organic matter in pipeline biofilms may consume chlorine/chloramines and form disinfection byproducts (DBPs), such as dichloroacetonitrile (DCAN) and dichloroacetamide (DCAcAm), two highly toxic nitrogenous DBPs (N-DBPs) species. The objectives of this study are to investigate the formation of DCAN and DCAcAm during chlorination and chloramination of pipeline biofilms, model bacterial cells and the corresponding extracellular polymers (EPS). DBPs formation from natural organic matter (NOM) and source water was also evaluated for comparison. The results show that DCAN and DCAcAm formation from chlorination of Pseudomonas aeruginosa, Pseudomonas putida and Micrococcus luteus selected as model species in biofilms were 1.48~2.02 μg·mg-1 and 0.21~0.38 μg·mg-1(mg-1 is per mg TOC), respectively, which were higher than those from chlorination of NOM. During chloramination, the bacterial cells formed less DCAN and DCAcAm than during chlorination. The bacterial EPS also acted as DCAN and DCAcAm precursors during chlorination and chloramination, with higher DCAcAm formation during chloramination than during chlorination. To evaluate the speciation of DBPs formed from chlorination of pipeline biofilms, the ratios of DCAN and DCAcAm concentration to trichloromethane (TCM) concentration were calculated and found to be higher than the corresponding ones for NOM and source water, suggesting that biofilms are more prone to form DCAN and DCAcAm than NOM and source water organic matter during chlorination. The biofilms formed more DCAcAm during chloramination than during chlorination. These results suggest that biofilms acted as important precursors to form DCAN and DCAcAm in drinking water distribution systems.
