AWWA WQTC60691

Free chlorine is widely used as a primary and secondary disinfectant for drinking water. When disinfection byproducts (DBPs) are concerned or where the free chlorine residual is difficult to maintain, chloramines are usually used to provide a stable disinfection residual in distribution systems. Kinetic models for chloramines have been developed by researchers in a bench-scale level. Chloramines are formed when free chlorine and ammonia are mixed in a turbulent environment. Currently, experience and rule of thumb are used in the design of mixers that are used in the chloramination process. In this study, CFD models combing the chloramines kinetic model and the turbulent micro-mixing model were developed and tested against tracer testing and pilot-scale testing. A new micro-mixing model multi-fluid model (MFM) was used together with the traditional species transportation model. Numerical simulations were compared with experimental measurements to evaluate the model's performance. Includes 4 references, table, figures.