Central Treatment Plant upgrade right on schedule
Photo by JOSH MCDONALD The Central Treatment Plant in Kellogg. The plant has been in operation for more than 40 years, but is being upgraded now as part of a $48 million project. It was initially built exclusively for use of the Bunker Hill Mine, but will now be used to treat any contaminated ground water that gets pumped to it. The current plant can treat up to 5,000 gallons of water per minute, but will be expanded to handle upward of 10,000 gallons per minute by the time of its completion.
KELLOGG — Work is on schedule next to I-90 as crews continue to construct a new groundwater collection system between the south side of the highway and the central impoundment area (CIA).
The groundwater collection system is part of a $48 million dollar project that was awarded last year by the U.S. Army Corps of Engineers to upgrade and expand the currently operating Central Treatment Plant at the Bunker Hill Superfund site in Kellogg.
The ACE is supervising the dismantling and corresponding upgrade of the existing plant, which currently treats two million gallons of wastewater daily from the Bunker Hill Mine.
Work began earlier this year with the dismantling of the billboards along I-90 so that crews could begin to dig down deep to begin the construction of a wall that will block water from going beneath the highway and into the South Fork.
A separate and temporary treatment system has been set up so that continuous treatment can happen while demolition and reconstruction occurs at the main plant.
August may be in the latter part of the normal construction season, but officials with the Environmental Protection Agency expect crews to finish up several projects this year, including several at the CTP:
- Demolishing select existing CTP facilities and begin construction of upgraded facilities.
- Constructing effluent pipeline over the CIA.
- Constructing expanded sludge containment facility atop the CIA.
- Constructing an in-water treated effluent discharge and diffuser structure at the South Fork of the Coeur d’Alene River that will meet water quality standards.
Alongside I-90 crews are working to finish the groundwater collection system, but still have a few major milestones to hit including:
- Installing groundwater extraction wells and piping.
- Constructing collection system piping between collection point and CTP.
- Installing subsurface Bentonite/Soil cutoff wall to capture groundwater flow under the CIA.
“This project represents one of the largest cleanup investments in the Silver Valley in decades,” EPA project manager Ed Moreen said. “By treating both mine drainage and collected contaminated groundwater, this project will pay dividends in a cleaner, healthier South Fork of the Coeur d’Alene River. By so doing, it will make the Silver Valley a better place to live, work and play.”
The overall goal of the project is to improve water treatment, reduce the volume of sludge produced, and collect and treat zinc-contaminated groundwater that flows through mine waste and contaminated sediments under the CIA and currently discharges into the South Fork of the Coeur d’Alene River.
Project officials estimate the groundwater collection and treatment will reduce the zinc load flowing toward the river from under the Central Impoundment Area by up to 90 percent.
The upgraded plant will treat both drainage from the Bunker Hill Mine and contaminated groundwater collected from the new groundwater collection system.
Current treatment capacity of the plant is approximately 2,500 gallons per minute (GPM), while the upgraded facility capacity will be designed to fully treat 5,000 gpm and is designed to accommodate future expansion of an additional 10,000 gpm.
The work is part of a required remedial action under the U.S. Environmental Protection Agency’s larger efforts to clean up toxic contamination in the basin.