Engineers present 30% design for Chickasha water treatment plant; 6 MGD with room to expand

Jason Coughlin of engineering firm Friese & Nichols presented the Chickasha City Council with a 30% preliminary design for a new conventional water treatment plant that the firm says will reliably deliver 6 million gallons per day and be laid out to allow expansion to 8 MGD.

Coughlin said the project is being delivered in five phases and that the preliminary design—accompanied by geotechnical and survey work—includes updated cost estimates that fit within the city’s available funding. “As we build definition on a project, you can hone in on costs a little bit as well,” he said.

The design restores a year‑round powdered activated carbon (PAC) pretreatment step to address recurring taste and odor problems. Coughlin explained PAC will be stored and fed from an upgraded pretreatment building and mixed into a carrier water before introduction to treatment. He told council the Department of Environmental Quality (DEQ) previously flagged the old PAC building for electrical and ventilation issues tied to storing and feeding powdered chemicals, and the project includes upgrades to meet those requirements.

Coughlin described the treatment train as conventional—rapid mix, coagulation/flocculation, sedimentation, filtration and disinfection—and said the firm is producing the design in Revit 3‑D so staff and contractors can virtually walk the asset before construction. He estimated the final design would be submitted to the state for review in January, go out to competitive bid in March with bids opening in May, and anticipated roughly 18 months of construction once a contractor is selected. He also noted the project scope includes decommissioning and demolition of the existing plant after the new plant is commissioned.

On redundancy and reliability, staff and the presenter confirmed backup power (generators) and certain longer‑lead items are being tracked because lead times could affect construction schedule. Coughlin said supply planning indicates 6 MGD should meet demand out to mid‑to‑late century under current projections, with room to add the 2 MGD later if growth is faster than expected.

The presentation closed to questions; council members asked for timing on PAC building upgrades and for confirmation the new design accommodates field‑identified water quality variability in Fort Cobb and Lake Chickasha samples. Coughlin said the team will continue sampling and build the final design to cover seasonal variation.