A project in Minnesota that will transform heat from decomposing trash into a powerful energy source may revolutionize the way other states think about their landfills.
As detailed by Minnesota Public Radio, the St. Louis County regional landfill near Virginia, Minnesota, intends to harvest the heat released when waste breaks down and use it to power a new plant to treat toxic "forever chemicals" in wastewater.
The idea may sound challenging, but according to St. Louis County director of environmental services Dave Fink, "It really is a simple concept," as trash releases a lot of heat — at temperatures up to 120 degrees Fahrenheit — as it decomposes.
"I couldn't believe that it hadn't been done in Minnesota or somewhere up north where you were capturing that free source of energy and free source of heat," Fink said to MPR News.
To capture the heat rather than allow it to enter the atmosphere, where it would contribute to the accelerated warming of the planet and the subsequent uptick of more intense extreme weather, St. Louis County laid eight miles of tubing under a new 10-acre section of the landfill.
The tubes are filled with a liquid that can transfer the trash-produced geothermal energy to a $15-17 million, 10,000-square-foot wastewater treatment plant set to break ground in summer, reducing the need to burn dirty fuels for heating operations. Officials are also considering adding solar panels to help power the plant.
Moreover, the "closed-loop system" of treatment for the hazardous forever chemicals, also known as PFAS, eliminates the need to ship the leachate to another facility, an expensive process that would cause even more pollution if the trucks ran on gas or diesel rather than electricity. Scientists have linked PFAS exposure to myriad severe health complications, including cancer, making proper treatment of such chemicals a pressing public health issue.
The first phase of the project cost $3 million, but the geothermal technology was only about 1% of the cost, according to MPR.
Stantec senior environmental engineer Brett Ballavance, who recommended the tech, assisted with a similar initiative in New Hampshire and believes the investment will more than pay off, as traditional geothermal systems only extract heat from the ground at around 40 degrees in winter.
"I think every landfill should do it," Ballavance told MPR. "It was eye-opening. And for the cost, it's a worthy investment."
As for the wastewater facility, state officials intend to monitor its success and the costs involved in PFAS treatment. The Minnesota Pollution Control Agency estimated that removing just one pound of PFAS from landfill leachate costs $400,000 to $12 million over two decades.
Nonetheless, state officials still lauded the plan as being "ahead of the curve" as they focus on preventing PFAS contamination going forward. Amara's Law, which goes into effect Jan. 1, bans manufacturers from using PFAS during the production of cosmetics, cookware, and more.
"We have the cleanest water in the state of Minnesota," St. Louis County Commissioner Keith Nelson told MPR. "We want to keep it that way now and into the future."
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