Hybrid Physical/Analytical/CFD Modeling Approach to Design of Detroit’s Wastewater Effluent Disinfection System

At the Great Lakes Water Authority (GLWA) Water Resource Recovery Facility (WRRF) in Detroit, Michigan, primary and secondary treated effluent is discharged to the Detroit River Outfall (DRO) and Rouge River Outfall (RRO). The most recent national pollutant discharge elimination system (NPDES) permit requires GLWA to disinfect all flow discharged from the plant. Currently only the existing DRO system is equipped with disinfection facilities. A comprehensive hydraulic evaluation was required to determine whether sufficient chlorine disinfection contact times could be achieved for the RRO system given its much shorter length. This evaluation was a hybrid approach that utilized a combination of physical, analytical and computational fluid dynamics (CFD) modeling. This paper reviews how the modeling tools were used to demonstrate that the NPDES permit requirements could be met.