On Line Control Strategies for Disinfection Systems: Success and Failure

There are many levels of automation for control of chlorination systems. To select the best control approach for a facility, both control strategies and chlorination chemistry must be understood. Permit conditions including organism concentrations and operating data must also be fully identified. Many States require compliance with organism concentrations, as well as residual chlorine and disinfection byproduct concentrations.Breakpoint chlorination chemistry will play a role in most disinfection systems. This paper discusses combining on-line monitoring and automated control with chlorine chemistry to develop several levels of process control that will result in effective disinfection. Another factor must be considered while developing a process control strategy is disinfection byproduct formation. Disinfection byproducts (DBPs) in wastewater effluent are being regulated and the limits being imposed are much stricter than SDWA standards. Data from a recent disinfection study is presented to examine DBP formation and other selected chemical properties.