Modelling chlorine residuals at Jabal Amman water supply

The purpose of the study presented in this paper is to test the ability of WaterCad, which simulates chlorine concentrations throughout water supplies, in predicting chlorine concentrations in the Jabal Amman distribution system and hence provide a tool to water supply operators in Jordan that helps them to better manage chlorine concentrations throughout distribution systems. To achieve this goal a sampling programme that aimed at measuring chlorine concentrations throughout Jabal Amman over time was conducted over a 2-year period. Half of the data collected was used for model calibration and the other half was used for model verification. Results showed good agreement between measured and simulated chlorine concentrations.

An important input for WaterCad is bulk chlorine decay coefficient. So, bulk chlorine decay coefficient for Zai Water Treatment Plant effluent, which supplies water to Jabal Amman, was modelled in terms of initial chlorine concentration, total organic carbon and temperature based on laboratory experiments. The developed mathematical model was used to determine bulk chlorine decay coefficient for the conditions of initial chlorine concentration, total organic carbon and temperature observed at the time of sampling, the determined bulk chlorine decay coefficient was then input into WaterCad.