Soil and Groundwater Remediations

Soil remediation in Tranemo (Sweden)

The remediation project in Tranemo, Sweden, is located on a former wood impregnation site. The soil is contaminated to a depth of six metres under the surface with pollutants typical of this sector of industry, primarily arsenic, copper and chromium.

The cause of the contamination was the continuous leakage of salts used for impregnation into the soil where the wood was dried between 1940 and 1970. What remained once the plant activities stopped was a site with very high concentrations of heavy metals in the soil.

A second part of the site was the former saw shop where the soil is also contaminated with heavy metals, although to a lesser degree.

The nature of the site caused it to be neglected for a long time after the activities stopped, so it became a place where all kinds of refuse was dumped.

The first part of the project consisted of demolishing the former buildings and offices. All waste products were selectively collected and hauled away to different certified disposal sites in Sweden.

Given the good physical characteristics of the soil on the site, a sandy soil with a considerable portion of gravel, physical/chemical treatment of the soil proved to be a good, economical solution. DEC can thus recycle 90% of the treated soil as sand and gravel. The other 10% is fine material (< 63 μm), that retained most of the contamination. This material (total 2.550 tds) was mechanically dewatered using a screen belt press. The remediated fractions were reused on the site as construction material.

At the end of the project, 40,000 tonnes of contaminated soil will have been treated with a recycling factor of 90%. The site will be reused as an industrial site in Tranemo. At the end of the work, DEC will have upgraded a zone of 35,000 m².