The remediation of the old Penttila’s sawmill area

The Penttilä sawmill area environmental project is the biggest of its kind in Finland

The old Penttilä sawmill in Joensuu was closed in 1988. At the time, the scope of the effects of the Ky 5 compound, used as a wood preservative, was not yet known. When the city of Joensuu bought 32.8 hectares of land in the sawmill area in 2008 to build there a residential area, it took on the remediation of the soil contaminated by dioxin, furane and heavy metals. The remediation project of the Penttilä sawmill area in 2009-2011 is one of the biggest undertaken in Finland. The log pond, three hectares in area, proved especially difficult to cleanse. City officials chose suction dredging as the method, combined with geotube and polymerase technology.

Originally soot black water turned crystal clear in the purification process. We managed to dry out the sludge pumped in geotubes so well that a common landfill sufficed for final disposal safely and economically to boot.”

Tero Toivanen, Head of the Joensuu city technical center

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