AWWA QTC98344

The objective of this paper is to present a practical method of optimizing disinfection credit in both existing and new or modified facilities. The dimensionless CT model could be used to optimize disinfection credit for the range of water quality and flow rates that the treatment processes will handle and could also be used in conjunction with a hydraulic model to optimize disinfection system design for new or existing water treatment facilities. The dimensionless CT model can also be used at existing water treatment plants as an operating tool to optimizing disinfection CT credit. However, the disinfection credit used to verify compliance with the disinfection portion of an overall removal-inactivation requirement must be based on criteria acceptable to the regulatory agency. The dimensionless CT model provides a practical method of optimizing compliance with disinfection requirements, rather than modeling pathogen inactivation. This can be done using plant design and pilot plant or plant operating data to perform the optimization.