Modeling Spatial Variation of Brominates Trihalomethane in a Water Distribution System of Ontario, Canada

Abstract

Conventional approaches to characterize and model the formation of trihalomethanes (THM) species in the distribution system use either residence time or water temperature. A significant deviation of THM levels were observed at the beginning and the end of a selected distribution system in Ontario, which may be because the consumption rate of residual chlorine is not constant in the distribution system. The approach developed in this study incorporates water temperature and proceeds with a trend and decomposition modeling method to incorporate the traveled distance and to explain the seasonal THM variation in the distribution system. The model has been tested and verified using a database from the Bettravia distribution system in Ontario, Canada. The deviations at the extremes of the distribution system were minimized due to the modeling technique used to develop the model and by including more factors that affect THM formation in the distribution system. The agreement between predicted and measured THM values at the beginning and the end of the distribution system is pronounced. The model presented in this paper is a robust tool that may be used by SDWAA to evaluate regulatory options and justify potential regulations regarding THM levels of the drinking water distribution system.

Key Words:

• Trihalomethane compounds
• Traveled distance
• Water temperature
• Trend
• Decomposition
• Distribution system

ACKNOWLEDGMENTS

The authors are grateful to the Canadian Drinking Water Quality Divisions of both Ontario and Ottawa Canada, for supporting us with the database of water quality parameter and THM four components at two treatment water units and distribution systems to use and collect the necessary information to accomplish this study.