在美国和欧洲，游离氯（Cl2）仍然被广泛用作后消毒剂。在典型条件下，添加Cl2作为工艺序列中的最后一步，通常在分配之前先添加接触池和/或储存。受管制和即将受管制的氯化副产物，包括三卤甲烷（THM）和卤乙酸（HAAs），很容易在接触池内形成，因此，代表着植物形成。然而，随着Cl2残留量的维持，THM和HAA也可在配电系统内形成。在这项研究中，THMs的预测模型被用来模拟这两种情况- THMs的工厂和配电系统级别。收集了一个数据库，描述了一个由三个处理厂供电的公共分配系统，这些处理厂进行氯化处理，服务于法国巴黎郊区。通过将化学（副产品）模型与提供运输时间估计的水力模型耦合，完成了配电系统建模。采用经验方程形式的化学模型预测三卤甲烷，并将其作为相关水质、处理条件和反应时间的函数。虽然本研究集中在一个案例上，但概念方法可以转化为存在水力模型的任何系统。

Free chlorine (Cl2) is still widely used as a post-disinfectant in both the United States and Europe. Under typical conditions, Cl2 is added as the final step in a process train, usually followed by a contact basin and/or storage prior to distribution. Regulated and soon to be regulated chlorination byproducts including both trihalomethanes (THMs) and haloacetic acids (HAAs), readily form within the contact basin and, as such, represent in-plant formation. However, with maintenance of a Cl2 residual, THMs and HAAs can also form within the distribution system. In this study, predictive models for THMs were used to simulate both in-plant and distribution system levels of THMs. A database was assembled describing a common distribution system fed by three treatment plants that practice chlorination and serve the suburbs of Paris, France. Distribution system modeling was accomplished by coupling chemical (byproduct) models with hydraulic models which provide estimates of time-of-transport. Chemical models in the form of empirical equations were used to predict THMs as a function of relevant water quality and treatment conditions, and reaction times. While this study focused on one case, the conceptual approach can be translated to any system where a hydraulic model exists.