Renovations of Pierce County’s Chambers Creek Regional Wastewater Treatment Plant have increased sewer capacity that should keep up with the county’s population growth until 2040. The project was the largest capital improvement project in Pierce County history.
The $342 million project lasted four years and increased the plant’s capacity by 15 million gallons a day to 44 million gallons per day and nearly doubled the plant’s footprint from 49 acres to 89 acres. The Pierce County sewer system collects wastewater from a 117-square-mile area with a population of 294,000 people in University Place, Lakewood, DuPont, Steilacoom and a portion of Tacoma. It also serves the unincorporated communities of Parkland, Spanaway, Midland, South Hill and Frederickson.
“Our treatment plant is vitally important to future economic growth throughout Pierce County,” said Pierce County Executive Bruce Dammeier at the facility’s grand reopening earlier this month. “Well maintained infrastructure supports our communities and ensures our ability to live, work and play.”
Pierce County Council members, local state legislators, and Public Works staff held tours and a ribbon cutting ceremony of sorts earlier this month. But instead of the standard red ribbon and scissors, Planning and Land Services Director Dennis Hanberg tore a stream of toilet paper. Dammeier and County Council Chair Doug Richardson then flushed a ceremonial toilet before receiving tours of the plant.
“Thousands of people will flush their toilets and not have to think anything else about it,” Dammeier said.
Ground work for the project began in 2010 with construction beginning in 2013. Work ran nonstop for four years, except during a one-month hiatus during the U.S. Open in 2015. Minor construction work will likely run through early 2018, but the plant is functionally completed. The work upgraded all components of the plant, some of which dates to the early 1980s, when the plant was first built. Improvements include added capacity, increased odor control, new utility tunnels, new electrical systems and new on-site laboratory. New and upgraded facilities increase processing capabilities to substantially reduce nitrogen from the water discharged into Puget Sound.
The plant uses a combination of physical and biological treatment processes to treat residential and commercial wastewater and sewage. Liquids from incoming wastewater are separated from solids at the plant and are then treatment before being discharged into Puget Sound. The process can take about a month and a half. The solid waste materials are refined into a dry pellet and sold as SoundGRO fertilizer to local and commercial customers. Some solids, including grease, however, are disposed of at a sanitary landfill.
“This project will allow the county to grow while keeping our sewer rates as some of the lowest in the region,” said Hanberg. “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 was $11 million under budget and was done with 1.3 million hours of construction work without an injury. M.A. Mortenson Co. served as general contractor while Brown and Caldwell was the lead designer. EC Electric was the electrical contractor and construction manager, while Prospect Construction and Carollo Engineering served as leads for the disinfection project. About 350 trade construction and electrical workers were on-site during the renovations.
Funding for the renovations came primarily through a series of 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.
The plant remains closed to the public until the final work is completed, but public tours will return in the fall to showcase the state-of-the-art facility.