St. Louis County’s geothermal landfill cell the first of its kind

St. Louis County is leading the state and the nation in implementing geothermal technology and the treatment of harmful chemicals at its regional landfill in Virginia.

A 10-acre geothermal landfill cell that generates energy from disposed municipal solid waste is the first of its kind in Minnesota, Dave Fink, St. Louis County Environmental Services director said.

That, coupled with a new system being developed to treat harmful chemicals such as PFAS (perfluoroalkyl substances), puts St. Louis County at the forefront of cutting edge state and national wastewater treatment clean-up.

“This is a commitment to the cleaning up of wastewater in northeastern Minnesota,” St. Louis County Sixth District Commissioner Keith Nelson, chair of the county board and chair of the county’s Solid Waste Committee said. “At the end of the day, the water at the landfill will be cleaner than the water that falls on the landfill.”

Construction on the geothermal cell is expected to be complete this week, Fink said.

The county will then begin depositing municipal solid waste into the cell.

“Everybody involved is pretty excited about it including our regulator, our commissioners, as well as our consultants,” Fink said. “They’re looking at actually utilizing this on a national stage in looking at what we’re doing at our relatively tiny landfill here in northern Minnesota.”

Creating geothermal energy from municipal solid waste stored in the cell will help heat a new 10,000 square-foot wastewater treatment plant to be built at the landfill in 2026.

By November, energy generated from municipal solid waste placed into the cell will begin producing heat to be used when the 10,000 square-foot wastewater treatment facility is completed, Fink said.

Generating heat from household garbage may not sound exciting.

But to the county and others, it’s a big step forward at the 42-acre landfill located on a former iron mining dump east of Virginia.

Heat of 90 to 140 degrees Fahrenheit will be produced from municipal solid waste deposited in the cell, Fink said.

The heat will then be recouped through six miles of pipe containing an antifreeze liquid and used as the primary heat source for the new 10,000 squarefoot wastewater treatment facility. Other buildings at the landfill could also be heated from the geothermal system, saving the county about $40,000 a year in propane heating costs, Fink said.

Even more importantly, the system by the end of 2026 will be connected to a first-in-Minnesota wastewater leachate treatment system within the new 10,000 square-foot plant.

The leachate system will treat and clean chemicals such as PFAS, boron and other chemicals that become a byproduct of waste stored within the entire 42-acre landfill, county officials say.

PFAS, a “forever chemical” found in many products, has emerged as a major problem at disposal sites across the nation.

Exposure to PFAS has been linked to serious health effects, according to U.S. Food and Drug Administration.

Treating the PFAS also requires heat, another benefit of the geothermal system, Steve Pellinen, St. Louis County senior planner said.

Once the PFAS is treated and cleaned, it will be stored in ponds and then applied to fields at the landfill, Fink said.

Constructing the first onsite PFAS treatment system in the state is a major committal by St. Louis County in the clean-up of wastewater and protection of the environment, county officials say.

“This is the biggest thing that’s ever been done in my tenure,” Nelson said. “This is cutting edge technology.”

With completion of the project, St. Louis County will become one of the first in the nation to treat PFAS and other chemicals and the only landfill in Minnesota to utilize geothermal technology to capture and re-use heat generated by municipal solid waste, county officials said.

Nelson said it’s a reflection of northeastern Minnesota’s overall commitment to clean water.

“When people talk about the Iron Range being mining polluted, the Iron Range is leading the way with this in cleaning up wastewater,” Nelson said. “We are leading the way in the treatment of wastewater because we already have the cleanest water and we are going to keep it that way.”

The 10-acre geothermal project cost is about $3 million, Fink said.

Nelson said the entire project is $18 million. The geothermal project is funded by St. Louis County’s Environmental Services and the PFAS wastewater treatment project by state grant and federal American Rescue Plan funding.

The projects will not result in increased costs to county taxpayers.

“There will not be any local property taxes,” Nelson said. “It’s all coming from the federal government and state of Minnesota.”

The landfill in Virginia opened in November 1993 and accepts an average of about 75,000 yards of municipal solid waste per year, Fink said.

The new technology combined with potential expansion could extend the life of the landfill for decades, Pellinen said.

“For garbage management, this is as exciting as it gets,” Fink said. Construction on a St. Louis County demolition landfill in Canyon is also underway, Nelson said.

The county has already received $4 million in funding for the Canyon project and is seeking another $6 million from the state during the 2025 Minnesota legislative session, Nelson said.

Th e Canyon facility will also include a wastewater treatment plant, Nelson said.