LIBERTY TOWNSHIP — Do you ever think about what happens after you flush your toilet or run the sink?
After you use water in your home, the wastewater and gray water maneuvers its way through a series of pipes that eventually lead to the wastewater treatment plant.
Once there, it undergoes an intensive treatment process to disinfect the water before it’s re-released back into a suitable water source.
The Olentangy Environmental Control Center recently upgraded how it treats wastewater before releasing treated water into the Olentangy River.
The facility, known as OECC, serves Powell, Liberty, Berlin and Concord townships and portions of Orange Township. It takes in roughly 4 million gallons per day.
Delaware County Commissioners and the Delaware County Regional Sewer District cut the ribbon on the newly-upgraded OECC Monday afternoon.
$46 million upgrade to plant
The renovations took nearly four years and cost $46 million — more than the county spent on the 4.5-mile major extension of the Sawmill Parkway and the in-progress Shared Services Building.
The project included two new buildings — a storage facility and a screening building designed to remove debris from incoming wastewater — along with equipment upgrades throughout the treatment process.
Operations Superintendent Jason Watts said some of the upgrades include:
- A new influent pump station with efficient pumping,
- A robust control system that can handle and manage heavy flow,
- An automatic debris screening system,
- New filters,
- Biological phosphorus removal instead of a purely chemical treatment process, resulting in a cheaper process,
- And a redundant centrifuge to act as a backup system for equipment failure or scheduled maintenance, eliminating the need for expensive rental equipment.
The Ohio Department of Development partially funded the project through a grant.
“We’re celebrating not only the completion of these renovations, but the skill and commitment of our regional sewer district staff in maintaining operations under very challenging circumstances,” Commissioner Jeff Benton said.
Those challenges included aging equipment that had stopped working, forcing staff to rent costly equipment to perform routine maintenance while the facility continued operating.
“Before this project started, this facility had equipment and technology that had reached the end of its life,” Watts said.
Watts said inefficient pumps and an outdated control system caused the station’s wet well — where incoming wastewater collects — to routinely flood during periods of heavy rain or high flow.
“We would lose sight of the depth of that wet well and have to manually take control of the influent pumps and manage that pumping rate,” he said.
The facility also lacked a screening system to remove unwanted debris from wastewater before it reached other equipment.
“Any unwanted debris, we had no way to get that out without it getting caught in equipment,” Watts said.
A unique approach to the project
Beyond its price tag, the project was also notable for its construction approach. It was one of the first public-sector projects in Ohio to use a process known as Progressive Design Build.
That process reduced the overall costs by an estimated $12 million, Regional Sewer District Director Tiffany Maag said in a press release.
Progressive Design Build does not bid out construction after design is completed, which is typical for county projects.
Instead, the engineering and construction firms collaborated on the design, thereby enabling better design decisions while lowering costs, according to the release.
The county worked with the Columbus office of design-engineering firm Arcadis U.S., Inc., and Peterson Construction Company of Wapakoneta, OH, on the project.
Located at 10333 Olentangy River Road just outside of Powell, the OECC was Delaware County’s first large-scale facility for wastewater treatment. It was originally built in 1979, then replaced by a second facility at the same site in 1994.
It’s the county’s second largest wastewater treatment plant, with the largest being the Alum Creek Water Reclamation Facility, but the city manages over a dozen smaller plants throughout the county, too.
The Delaware County Regional Sewer District serves more than 129,000 people with 550 miles of sewer lines.
County Commissioner Gary Merrell said there are also preliminary discussions for a potential fourth major treatment plant near the Alum Creek area to handle ongoing regional development.
