Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720, United States.
Water Res. 2010 Mar;44(5):1616-26. doi: 10.1016/j.watres.2009.11.015. Epub 2009 Nov 26.
Chlorination by-products may be formed during pretreatment or posttreatment disinfection in reverse osmosis (RO) desalination systems, potentially posing health, aesthetic and ecological risks. To assess the formation and fate of by-products under different conditions likely to be encountered in desalination systems, trihalomethanes, dihaloacetonitriles, haloacetic acids, and bromophenols were analyzed in water samples from a pilot-scale seawater desalination plant with a chlorine pretreatment system and in benchscale experiments designed to simulate other feed water conditions. In the pilot plant, RO rejection performance as low as 55% was observed for neutral, low-molecular-weight by-products such as chloroform or bromochloroacetonitrile. Benchscale chlorination experiments, conducted on seawater from various locations indicated significant temporal and spatial variability for all by-products, which could not be explained by measured concentrations of organic carbon or bulk parameters such as SUVA(254). When desalinated water was blended with freshwater, elevated concentrations of bromide in the blended water resulted in dihaloacetonitrile concentrations that were higher than those expected from dilution. In most situations, the concentration of chlorination by-products formed from continuous chlorination of seawater or blending of desalinated water and freshwater will not compromise water quality or pose significant risks to aquatic ecosystems.
氯代副产物可能在反渗透（RO）脱盐系统的预处理或后处理消毒过程中形成，从而对健康、美学和生态造成潜在风险。为了评估在脱盐系统中可能遇到的不同条件下副产物的形成和归宿，在采用氯预处理系统的中试规模海水淡化厂的水样中分析了三卤甲烷、二卤乙腈、卤乙酸和溴酚，同时还在设计用来模拟其他进水条件的台式实验中进行了分析。在中试工厂中，对于中性、低分子量的副产物（如氯仿或溴氯乙腈），RO 截留性能低至 55%。在各种地点的海水中进行的台式氯化实验表明，所有副产物都存在显著的时间和空间变异性，无法用测量的有机碳浓度或 SUVA（254）等整体参数来解释。当淡化水与淡水混合时，混合水中溴化物浓度的升高导致二卤乙腈的浓度高于稀释预期值。在大多数情况下，连续氯化海水或混合淡化水和淡水形成的氯化副产物的浓度不会影响水质或对水生生态系统构成重大风险。
