Engineers present 30% design for wastewater plant expansion; city aims to hold estimated construction cost near $40 million

City engineering consultant Strand presented a 30% design update for the Pataskala wastewater treatment plant expansion at the Utility Committee meeting, describing layout changes, regulatory clearances, schedule milestones and an estimated construction midpoint cost near $40,000,000.

A Strand representative told the committee the project's permit has been updated and approved by the Environmental Protection Agency and that the design process has consolidated several adjacent pump stations to reduce cost. The consultant showed plan graphics and three-dimensional renderings illustrating new tanks, a blower building to house blowers and compressors indoors, a small four-chambered tank dedicated to phosphorus removal, and a larger biological tank intended to address nitrogen removal.

Strand also described a new UV disinfection station to be built next to the existing UV station so the plant can remain in operation during construction, and a back-truck dump station (referred to in the packet as Structure 7) that will provide a compliant facility for haulers to offload liquid wastes. "This will bring the back truck dumping process into compliance with EPA regulations. Currently, we do not have a proper way to do that," the Strand representative said.

Engineers explained solids handling work flows: a gravity thickener (Structure 70) to increase solids concentration, repurposing the existing oxidation ditch as a large digester, routing material to existing square digesters and then to the press building. Strand noted the city does not need to increase the size of the existing press. Plans call for additional sludge storage capacity (a second half-dome storage barn foundation is shown) and a new storage building to replace garage storage lost to electrical room conversion in the administrative building.

On schedule and funding, Strand presented a timeline showing a construction bid date of Aug. 26 (year not specified in the packet), with final construction completion listed for October of a later year. Strand said the city plans to close on a construction loan through DIFA and award a construction contract late in 2026, with actual construction likely to start in early 2027 and midpoint construction costs reflecting 2028 bid pricing. "We're still at the $40,000,000 mark," the Strand representative said when summarizing the probable construction cost estimate.

Designers also said the project team had identified code-driven cost increases in some areas but made reductions elsewhere to hold the overall OPCC near prior estimates. They noted a priority-list nomination for EPA and other federal grant-readiness work is planned for December and that the project will submit the PTI (plan-review submission) in February for EPA review.

Strand demonstrated a 3D model that staff plan to use for staff training and orientation; the model allows virtual walkthroughs of the plant and shows piping, tanks and internal fittings. Treatment plant staff and committee members asked several operational questions about UV placement, the location and operation of pumps, and the role of the grate on Creek Road; engineers clarified the grate is the primary raw influent screen and will not be replaced as part of this project.

Committee members praised the Strand team's work to control costs and noted the design's attention to operator concerns. No formal committee action was taken during the presentation; the update was informational and intended to inform forthcoming loan, permitting and bidding steps.