Dioxin i mark : En undersökning kring saneringsmetoder in-situ och on-site.

Sammanfattning: Dioxins are among the most toxic substances known to man. Dioxins are hydrophobic organic molecules that accumulate in the food chain and can cause cancer and reproductive difficulties for both animals and humans. A common method for remediating contaminated soil is excavation and transporting the masses to a landfill site. That leads to large waste piles that occupy a lot of space and clean soil must be transported to the remediation area. By treating the contaminated soil, pure soil can remain untouched. The contaminated area can be treated at the spot (in-situ or on-site) and risks such as spread of polluted soil can be reduced, and transports can be reduced so the environment can be better protected. The purpose of this study is to evaluate remediation methods that is done in-situ or on-site for dioxin-contaminated areas and to make proposals for appropriate remediation methods for some selected dioxin-contaminated areas. For the remediation methods available to treat dioxin in-situ, soil washing seems to be an option. This method involves washing the soil with solvents to release the dioxin molecules from the organic material that it binds tightly to. The contaminated fluid is later pumped up to get disposed. Chemical oxidation, which is another method, is like soil washing but treats decontaminated pollutants that are in the groundwater. With the help of Fenton's reaction, the dioxin molecules can be destroyed, and no excavation is needed. Two other methods that have the potential to reduce the spread of dioxin contamination are stabilization / solidification and containment / barrier technology. These two are enclosing the pollution so it cannot be spread further in the soil. Thermal desorption is a method that can be used in conjunction with soil washing as a final step in destroying the dioxins. It can also be used separately and then heating rods are lowered into the ground which causes the dioxin to change to gas form. This method has also two other alternatives to heat up the pollution in the ground. By using hot water vapor thru the rods in the ground or by using electricity in predrilled holes in the ground and then suck the gas up thru pipes.  The gas with the pollutants is later sucked up to be purified through filters or by letting the pollutants pass through a combustion. When a contaminated area is going to be evaluated, there are some things that needs to be considered before making the choice of remediation method. It can be briefly summarized as a plan for what the area after decontamination will be used for and what is at the site today. These may be ancient remains, red-listed species that may affect the choice of remediation method. Likewise, the choice of method can be influenced if contaminated masses are to be driven to a remediation plant as it should be at an acceptable distance from the contaminated area, to reduce the climate impact. Both Bestorps f.d. sågverk and BT kemi in Teckomatorp who were studied, chose to excavate, and transport to an incineration plant (ex-situ). In this report it has emerged that the social, economic, and environmental aspects should be considered to achieve the best possible effect when choosing a remediation method, such methods are usually in-situ or on-site. Bestorps f.d. kemi and BT kemi in Teckomatorp could have been decontaminated by using soil wash and thermical treatment for the construction parts, such as the old warehouses, and then partly be treated in-situ and on-site and then tribute to reach some of the Swedish Miljökvalitetsmål.