Two projects that have tested how to clean soil of PFAS by heating it have been a clear success. Now the question is to find out which PFAS contaminants the technique should be used on.
It has long been an uphill battle with what to do with soil contaminated with PFAS. That's why it has been lying around for years. Because there were neither depots to transport the soil to, nor technology to clean it of PFAS.
But now there is light ahead. Two projects that have been carried out at the national PFAS testing center in Korsør have been a clear success. In both cases, it has been possible to clean the soil of PFAS. And this has happened without new hazardous substances being formed in the process.
"It is a huge step forward in the work of solving the challenges surrounding PFAS that we have now found the first technologies that can clean PFAS in soil," says Camilla Hove Lund, chair of the Danish Regions' Committee for Environment and Climate.
Warms the earth
Both projects use the same technique: They heat the contaminated soil until the PFAS disappears.
PFAS thus has a boiling point of up to 350 degrees before it evaporates. However, the two projects handle the technique differently. In one project, the PFAS is finally destroyed after it has evaporated. In the other, it is broken down while it is still in the soil.
However, the result is the same: The PFAS disappears.
"Now we have a technical solution. Then it's about finding the right projects where we can test how the technique works on a large scale and optimize the processes," says Camilla Hove Lund.
Doesn't solve everything
However, the new technique does not solve everything. It costs a lot of money to clean the soil in this way – also in terms of climate. Therefore, it can and should only be used in places where there is the most PFAS in the soil.
"There is no doubt that the two techniques will be an important part of our efforts against PFAS contamination. But they will not be the only one. There is still a need to find solutions for handling soil with lower PFAS content," says Camilla Hove Lund.
Facts
- The two projects are financed via a grant of 10 million kroner that the regions received in the Finance Act for 2023.
- The projects were carried out at the national PFAS testing center in Korsør – colloquially Korsør Fire School.
- A total of 60 cubic meters of PFAS-contaminated soil was used for the projects.
- The trials started in the spring of 2025 and ran until the summer.
- One project has been carried out by the Danish construction company Arkil together with the Belgian company Haemers.
- Here, the soil is heated to 350-450 degrees, causing the PFAS to evaporate. The air containing the evaporated PFAS is collected and passed through a 1,400 degree flame, which breaks down and completely destroys the PFAS.
- The second project has been carried out by the Danish company Krüger.
- Here the soil is also heated, but slowly so that most of the PFAS is broken down while it is still in the soil. The rest is then collected in a defluorinator and broken down there.
The Danish Environmental Protection Agency has calculated that over the next 10 years there will be a need to handle 150,000-500,000 tons of PFAS contaminated soil. Until now, it has not been possible to handle this soil in Denmark.