Minnesota county to implement geothermal technology, PFAS treatment at regional landfill

St. Louis County, Minnesota, will implement geothermal technology and per- and polyfluoroalkyl substances (PFAS) treatment at its regional landfill.

As reported by the Mesabi Tribune, a 10-acre geothermal landfill cell that generates energy from disposed municipal solid waste (MSW) will be the first of its kind in the state. This will be coupled with a new system being developed to treat PFAS.

“This is a commitment to the cleaning up of wastewater in northeastern Minnesota,” says St. Louis County 6^th District Commissioner Keith Nelson, chair of the county board and chair of the county’s Solid Waste Committee. “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 completed this month.

Creating geothermal energy from MSW stored in the cell will help heat a new 10,000-square-foot wastewater treatment facility (WWTF) to be built at the landfill in 2026.

Heat reaching 90 to 140 F will be produced and recoupled through six miles of pipe containing an antifreeze liquid and used as the primary heat source for the WWTF. Other buildings at the landfill could also be heated from the geothermal system, the Mesabi Tribune reports, saving the county about $40,000 a year in propane heating costs.

By the end of 2026, the system will be connected to a leachate treatment system within the WWTF. The leachate system will treat and clean chemicals such as PFAS and boron. Once PFAS are treated and cleaned, they will be stored in ponds and then applied to landfill fields.

With the completion of the project, St. Louis County will become one of the first in the nation to treat PFAS and other chemicals using landfill geothermal technology. The total cost of the project is projected at $18 million, with $3 million designated for the geothermal cell project.

The geothermal project is funded by St. Louis County’s Environmental Services, and the PFAS treatment project is funded by state grants and the American Rescue Plan.

The 42-acre regional landfill is located on a former iron mining dump east of Virginia, Minnesota. It opened in 1993 and accepts an average of 75,000 yards of MSW per year.