A groundbreaking full-scale study to increase plant capacity

Camrosa Water Reclamation Facility Disinfection Study

The Camrosa Water Reclamation Facility (CWRF) provides recycled water for crop irrigation, but it was limited in the volume it could produce. The chlorine contact basins, which predated the rest of the treatment facility, were not large enough to meet the default regulatory minimum chlorine contact times.

We developed a testing protocol to investigate whether the existing chlorine contractors could be re-rated to accommodate higher flows while maintaining compliance with recycled water disinfection standards. We worked with the CWRF operators to configure the plant for experiments at full scale and conducted a suite of testing that included fluoride tracer studies to measure the actual contact time, chlorine degradation studies to set a dosing strategy, and virus seeding studies with MS2 bacteriophage to observe the rate and extent of disinfection.

Our work demonstrated that the plant could meet the disinfection standards at much lower than the default regulatory minimum time. The results gained the approval of the California regulators to operate the disinfection process at a higher flow rate. The result? No need to construct larger cholorine contact basins and a significant cost savings for the District.