AWWA JAW70393

Water utilities must ensure that adequate residual concentrations of secondary disinfectants persist throughout the distribution system to prevent bacterial regrowth. To predict disinfectant concentrations, a utility must use a combination of modeling and water quality field sampling, which is expensive. The need for sampling can be reduced if a utility has a more robust water quality modeling capacity. This study extends the understanding of the rate of chloramine decay in the distribution system, enabling utilities to make better predictions of chloramine residuals and, perhaps, to reduce the amount of costly sampling required. This research demonstrates that a simple, inexpensive new lab method, the pipe section reactor, can be used to systematically study the rate of disinfectant decay in various pipe materials and water quality conditions. In addition, this study provides kinetic models that can be used to predict chloramine decay rates in all distribution systems. Includes 25 references, tables, figures.