The regular monitoring of disinfection performance (CT) at water treatment plants (WTPs) is an
important function for facility operators to verify the proper operation of disinfection systems and the
quality of the treated water. In North America there is a regulatory trend towards the mandating of CT
monitoring and reporting, and the Province of Alberta, Canada recently required The City of Calgary
Waterworks to design and implement online real-time CT Monitoring Systems. This paper provides a
detailed summary of key design lessons and issues that should be considered by other WTP
operators interested in pursuing a similar manual or fully automated system for their facility. The
paper discusses the possibility and approach of creating only a computer spreadsheet model to
provide CT Calculations for any WTP, and then extends the discussion to the full automation of that
model for online real-time functionality. The implementation and use of a powerful CT Simulator for
system contingency is discussed, and the process optimization and cost saving benefits that the City
receives from having implemented the Systems is high-lighted. Includes 7 references, tables, figures.