AWWA QTC97066

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.

Product Details

Published:

01/01/1997

ISBN(s):

0898679583

Number of Pages:

20

File Size:

1 file , 160 KB