Abstract：
With increased understanding of the differences in toxicity between species of haloacetic acids (HAAs) and the possibility of more stringent regulations, the ability to predict individual HAA species formation is important. Nine different haloacetic acids are regulated and their total concentration is referred to as HAA9. A mathematical model to predict concentrations of HAA species was proposed and tested using independent data sets. The amount of HAA9 formed per unit amount of chlorine consumed (μg-HAA9/mg-consumed chlorine) remained constant throughout the reaction times in each sample. Similarly, the fraction of a given HAA species largely remained constant during most of the reaction time. Thus, each HAA species was assumed to have its own yield with respect to consumed chlorine in a given water sample. The parallel second-order (2R) model describing chlorine decay kinetics was then extended to predict HAA species formation kinetics. The combined chlorine and HAA species model closely predicts all tested HAA species and its sum with standard error ≤ 5 μg/L. Within the tested waters having Cl2/N mass ratio ≥ 10.7 (g-Cl2/g-N), ammonia did not impact the mass yield. The mass yield of each HAA species can be calculated from three measurements (e.g. at 0, 4 and 24 h) of HAA species and chlorine. Once the yield is known, HAA species concentrations could be predicted for up to 120 h with only chlorine measurements. The model extends the previous work of predicting the trihalomethane species formation kinetics to HAA species formation kinetics. Further research is needed to understand how the yield varies with source water quality, treatment and in distribution systems.
摘要：
随着对卤代乙酸（HAAs）物种之间毒性差异的日益了解以及更严格法规的可能性，预测单个HAA物种形成的能力很重要。调节9种不同的卤代乙酸,并且它们的总浓度被称为HAA9。提出了一种预测HAA物种浓度的数学模型，并使用独立的数据集进行了测试。在每个样品的整个反应时间内,每单位量消耗的氯形成的HAA9的量(μg-HAA9/mg-消耗的氯)保持恒定。同样，给定的HAA物质的分数在大部分反应时间期间基本上保持恒定。因此，假定每种HAA物种相对于给定水样中的消耗氯具有其自己的产率。然后扩展了描述氯衰变动力学的平行二阶（2R）模型，以预测HAA物种的形成动力学。氯和HAA物种组合模型紧密地预测所有测试的HAA物种及其总和，标准误差≤5μg/L。在Cl2/N质量比≥10.7(g-Cl2/g-N)的试验水中，氨不影响质量产量。每种HAA物质的质量产率可由HAA物质和氯的三次测量(例如在0、4和24小时)计算。一旦知道产量，仅通过氯测量，就可以预测HAA物种的浓度长达120小时。该模型将预测三卤甲烷物种形成动力学的先前工作扩展到HAA物种形成动力学。需要进一步研究以了解产量如何随水源水质而变化，治疗和分配系统。
