AWWA JAW60511

Current approaches for chlorine disinfection process design involve application of a C × T (concentration × time) concept or the integrated disinfection design framework (IDDF) (Bellamy et al, 1998). This study presents a new design approach for chlorine disinfection that uses computational fluid dynamics (CFD). CFD models were developed to predict flow structure, mass transport, chlorine decay, and microbial inactivation in a continuous-flow reactor and associated piping. Past CFD models for chlorine disinfection have only predicted chlorine contactor flow structure and residence time distribution (Crozes et al, 1999; Wang & Falconer, 1998; Hannoun & Boulos, 1997; Stambolieva et al, 1993). The model described here incorporates experimentally derived terms for chlorine decay (free and combined) and microbial inactivation ( Escherichia coli, MS2 bacteriophage, and Giardia muris) based on the work of Haas et al (1995). CFD predictions were in good agreement with the experimental data set over a wide range of microbial inactivation rates. Includes 26 references, tables, figures.