Expanded wastewater treatment plant opens

Major expansion of Pierce County’s Chambers Creek Regional Wastewater Treatment Plant is complete. Improvements increase sewer capacity, repair and replace aging infrastructure.

The project increases the plant’s capacity to 44 million gallons per day (MGD), an increase of 15 MGD. It nearly doubled the footprint of the plant from 49 acres to 89 acres. The upgraded facilities are designed to meet county population and economic growth through 2040.

“Our treatment plant is vitally important to future economic growth throughout Pierce County,” said Executive Bruce Dammeier. “Well-maintained infrastructure supports our communities and ensures our ability to live, work and play.”

All components of the plant – some of which date to the early 1980s – were enhanced or upgraded. Improvements include added capacity, increased odor control, new utility tunnels, new electrical system, and new on-site laboratory. New and upgraded facilities increase processing capabilities to substantially reduce nitrogen from the water discharged into the Puget Sound.

“This project will allow the county to grow while keeping our sewer rates as some of the lowest in the region,” said Dennis Hanberg, Planning and Public Works director. “This expansion supports our goal of providing high quality wastewater treatment to best serve our customers and the environment in which we live.”

The completed project is $11 million under budget, for a total of $342 million. It is funded primarily through a series of three bond sales. Each bond has a 30-year payback period. Additional funding comes from a $60 million Department of Ecology loan, connection charges for new developments, state grants, and monthly rates collected from sewer customers. 

Ground work for the project began in 2010 with construction beginning in 2013. Substantial completion was reached May 15. Minor construction work will likely run through early 2018.

Using the General Contractor/Construction Manager (GC/CM) project delivery method controls cost, optimizes schedule, mitigates risk and minimizes risk of permit violations. M.A. Mortenson Company is the GC/CM, and Brown and Caldwell is the designer. EC Electric is the electrical contractor/construction manager. In addition, Prospect Construction and Carollo Engineering are the leads for the UV disinfection project. Approximately 350 trade workers were on-site at peak work periods.

The Pierce County sewer system collects wastewater from a 117-square-mile area with a population of 294,000 people in the cities of University Place, Lakewood, DuPont, Steilacoom and a portion of Tacoma. It also serves the unincorporated communities of Parkland, Spanaway, Midland, South Hill and Frederickson.

Click to see drone footage of the Chambers Creek Regional Wastewater Treatment Plant.

Karl Imlig, P.E., Planning and Public Works wastewater utility manager
(253) 798-3011

Sean McDermott, Planning and Public Works public information specialist
(253) 798-2092