Walking the Line: Developing Control Strategies to Implement New Technologies and Meet Permit and Process Demands

The implementation of more restrictive regulations for disinfection byproducts (DBPs) for surface water discharges in California has resulted in numerous municipalities converting from chlorination to an ultraviolet (UV) disinfection. Although chlorination does generate DBPs, it is beneficial for recycled water (RW) as it provides a chlorine residual, which helps maintain and prevent bacteria and algae growth in RW systems. In addition, changes in the demand for different process waters varies throughout the day, which means that storage and/or equalization is often required to meet these demands. The separation and storage of effluent within a wastewater treatment plant (WWTP) to meet these demands requires significant forethought and careful integration into the plant's control strategy. Balancing DBP formation in effluent being discharged while maintaining a RW distribution system is a fine line that plant operators must walk. Two case studies – the City of Roseville, California, Pleasant Grove (PG) WWTP and the California Men's Colony (CMC) WWTP – are presented in this paper are that explore the development and tuning of control strategies to incorporate new technologies while meeting various permit requirements and plant demands.