An efficient soil remediation technology
After a longer test run, 90 tonnes of sand is cleansed of mercury and pesticides to a level where the majority can be used freely and the rest for construction purposes. It is now clear that the technology developed by Fortum Recycling & Waste to clean the sand at Groyne 42 is as effective as hoped. The now completed pilot test shows that the technology can remove 99.5 percent of the pollution in the sand.
In practice, this means that most of the sand meets the Danish Environmental Protection Agency's criteria for clean soil* and can therefore be used freely, while the rest is clean enough to be used for construction purposes - for example substrates for roads.
“Up to 80 percent of the contaminated sand can be cleansed by treating it once in the new plant. The remaining 20 percent must be treated twice, and thereafter it will meet the criteria in relation to both mercury and pesticides, so that it can be utilized for construction purposes. It is compelling and in line with what we had hoped and expected,” says R&D manager PhD Thomas von Kronhelm from Recycling & Waste.
The technology, commonly called MOPS (short for Multi-purpose Onsite Phase Separator), can roughly be termed as a large industrial washing machine with various steps. In the core of the process, sand is rinsed with a special liquid under high-pressure that separates the contaminated substances in a sludge phase. The process water is reused in the treatment. The sludge is transported to Fortum in Nyborg and treated by high temperature incineration. Then the sand is cleansed.
“We develop sustainable solutions that protect and recycle the resources of the nature. The MOPS technology has great potential both locally and globally, because many soil pollutants call for this type of purification process, and furthermore it is efficient and local,” says Kalle Saarimaa, Vice President, Recycling and Waste.
Danish generational pollutions - a national challenge
In March, the Regions in Denmark submitted a comprehensive plan for prioritizing, costing and cleansing the Danish generational pollutions to Environment Minister Lea Wermelin. Groyne 42 at Harboøre Tange, which for decades has been an unsolved environmental problem, is one of the pollutions that has been investigated and ready for clean-up.
Chairman of the Committee for Regional Development in Central Jutland Denmark Jørgen Nørby (The Liberal Party) welcomes the news from Fortum: “It is very positive that another Danish solution is now in play for the purification of our generational pollution, and we look forward to studying the results. At Harboøre Tange in Western Jutland, we have three major generational pollutions - the chemical depot at Groyne 42 and the chemical company Cheminova's old factory site are the two sites ready to be cleaned up. We still wait for the Parliament to prioritize the funding so that we can get started”.
The United Nations Food and Agriculture Organization (FAO) has also shown interest in the MOPS technology, which holds international perspectives on sustainable solutions to environmental challenges and resource recycling.
The MOPS technology in brief
The core of the MOPS treatment is the reactor where the contaminated material is flushed by a special liquid under high-pressure which separates the problematic components and release them into a liquid part. The succeeding treatment of the liquid makes the components precipitate into a sludge part that contains the problematic material, while the cleansed liquid part can be reused as process water. The MOPS treatment comprises a detoxification as well as a recovery of raw materials.
- MOPS is supported by the Danish Environmental Protection Agency's MUDP funds and deals with both detoxification and reprocessing of raw materials.
- Fortum's MOPS process focuses on three different matrices. Detoxification applies to the sand from Groyne 42. The other two matrices uncover the technology's potential for concentrating metals from fly ash and phosphorus from sewage sludge.
- Groyne 42 was used as a toxic waste dump in the years 1957 to 1962. The landfill is one of the historical Danish pollutions.