Dynamic Simulation Approaches To Mitigate Nonpermitted Wet Weather By-pass Risk And Optimizing Pumping Strategies At West Point WWTP

The West Point Wastewater Treatment Plant (WWTP) operated by King County, Washington experiences flows of 40 mgd to 440 mgd. The plant is in the middle of replacing its aging PLC system with an Ovation™ distribution control system (DCS). Historically there have been some operational challenges during wet-weather events associated with the plant’s Intermediate Pump Station (IPS) and Flow Diversion structure (FDS) when the existing controls initiates pump starts and stops. A Replica™ dynamic simulation model of the WWTP was calibrated against historical data and linked to the DCS to enable functional testing of programmed algorithms at the IPS and FDS. This testing environment enabled programmers to optimize algorithms in a low risk environment with the goal of mitigating non-permitted bypasses of secondary treatment during wet-weather events. This enabled King County staff and West Point operators to review and accept the new algorithm before implementation at the plant.