WWTP Evaluation – Plain City, Ohio

STONE was subcontracted to evaluate the performance, operation, and maintenance of a package wastewater treatment plant at this technical career center. The plant was installed in 1974, and contained a trash trap, pump stations, in-ground extended aeration package treatment plant, second surface sand filters, and chlorination. Drying beds were used to dry sludge generated from the clarifiers. The discharge from the treatment plant entered an on-site drainage swale that eventually discharged into Big Darby Creek, an Ohio Scenic River. The plant had a National Pollutant Discharge Elimination System (NPDES) permit and was designed to treat 20,000 gallons of wastewater per day.

STONE compared the design information used in 1973 with current published USEPA design standards and found most components met the requirements. While the scope of the evaluation did not include an in-depth assessment of each treatment component, STONE made treatment plant upgrade recommendations that included new dechlorination equipment, and converting the sludge drying beds into a sludge transfer facility to allow for pumping of liquid sludge directly to a hauling vehicle.

STONE concluded that the existing wastewater treatment facility had the hydraulic capacity and the proper treatment units to meet the NPDES permit conditions for a student and administrative population of 900 persons, assuming that the current operation and maintenance practices were continued and that adequate fiscal resources were available for prompt replacement of mechanical components.