我国南方典型自来水厂中游离氨基酸浓度及去除特性

Concentration Level and Removal of Fifteen Free Amino Acids in Eight Drinking Water Treatment Plants in South China

游离氨基酸是自来水中含氮消毒副产物的重要前体物,也是引起自来水异味的重要原因之一。基于LC-MS/MS方法调查了我国南方8个典型水厂中15种氨基酸的浓度水平和去除特性,以期为含氮消毒副产物和异味控制提供参考。结果表明,8个水厂中总游离氨基酸浓度最高的是G和H水厂,浓度分别为222.9、219.2 nmol/L;最低的是A水厂,相应浓度为107.6 nmol/L。H和D水厂对总游离氨基酸的去除率最高,分别为61.8%和56.7%;C水厂的去除率最低,为30.4%。在8个水厂中去除率最高的游离氨基酸为天冬氨酸和缬氨酸,分别为74.3%和60.6%;去除率最低的为色氨酸,仅为22.6%。在水厂加氯消毒环节,去除率最高的3种氨基酸分别为天冬氨酸、丝氨酸和异亮氨酸,相应去除率分别为21.9%、17.2%和15.0%;去除率最低的3种氨基酸分别为丙氨酸、苏氨酸和苯丙氨酸,去除率分别为5.4%、7.1%和7.2%。天冬氨酸是氯消毒中反应活性最高的氨基酸,常规水处理工艺对总游离氨基酸的平均去除率约为46.5%。

Amino acids(AAs)are important nitrogenous organics in water,which are also important precursors of many nitrogenous disinfection byproducts that cause odor problem in drinking water.This work investigated the occurrence and removal of 15 AAs in eight drinking water treatment plants(DWTPs)in South China based on LC-MS/MS.The data showed that G and H DWTPs had the highest total concentrations with respective concentrations of 222.9 nmol/L and 219.2 nmol/L,while the A DWTP had the lowest concentration of 107.6 nmol/L.H and D DWTPs shared the highest removal efficiencies for total free AAs,which were 61.8%and 56.7%,respectively.C DWTP had the lowest removal efficiency of 30.4%.The total average removal efficiencies of aspartic acid and valine in the eight DWTPs were 74.3%and 60.6%,which were the top two among 15 AAs.On the other hand,the corresponding removal of tryptophan was only 22.6%,which had the lowest removal.During the post chlorination process,aspartic acid,tyrosine and L-isoleucine had the highest removal efficiencies with respective removals of 21.9%,17.2%and 15.0%,while phenylalanine,glutamic acid and valine had the lowest removals of 5.4%,7.1%and 7.2%.Aspartic acid was the most reactive AA in chlorine disinfection.The average removal efficiency of the total fifteen free AAs by conventional disinfection process was about 46.5%.