In September 2017, Peterson Construction, CDM Smith Engineering, and Bowser Morner Testing began work on the Piqua WWTP expansion/upgrade project. This project now meets the February 2020 mandate and compliance schedule set forth by the Ohio EPA to eliminate Sanitary Sewer Overflows (SSO).
The new design is 8.7 Million Gallons per Day (MGD) and a new peak hourly flow of 22.5 MGD. Design flow is nearly twice that of the old plant and the new peak flow is nearly triple that of the old.
A new headworks structure was built. Components for this include, two 11 MGD, and two 5.5 MGD submersible pumps, mechanical screens, compactor/washing systems, stacked grit conical vortex trays, slurry, and dewatering equipment. This new building has an electrical room, a 1500-kilowatt standby power generator with switchgear, and a heated dumpster area.
From the headworks building, flow proceeds to both of the new extended aeration oxidation ditches. These ditches are modulated zones for Biological Nutrient Removal (BNR). From the ditches, flow continues into three 120’ diameter by 16’ sidewall depth final settling clarifier tanks. Between these final tanks is a new secondary control building with an electrical room and a basement for eight pumps.
Effluent flow from the finals travels to a new Ultraviolet (UV) disinfection station. Post aeration tanks were expanded upon and a new diffusing grid placed for dissolved oxygen (DO) supply. Three new vertical turbine pumps are installed for effluent pumping into the river when flooding conditions warrant.
Initial biosolids processing occurs in a repurposed solids thickening building. Three of the old aeration basins were converted into aerobic digesters and include three new positive displacement blowers for air volume. There was the construction of a new centrifuge building (lab, electrical room, restroom, polymer feed system, and maintenance area) with cold weather enclosed storage for biosolids on one end.
Other construction included relocating main power feed lines (special thank you to Piqua Power system), relocating an existing low-hour use a backup generator along with installing new switchgear. There was the construction of a new main electrical building. We have a new robust Supervisory Control and Data Acquisition (SCADA) system installed.