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Educational Sessions

Building Bridges

Tree Rescue on a Heritage Island in Stockholm, Sweden 
Tuesday, 11 August 2015
1:50 PM — 2:30 PM
Osceola Ballroom A
A, M, Bm

Beckholmen was a heavily contaminated island in the center of Stockholm. It belonged to the National City Park which was owned by the Swedish Royal Court! The need to remove the island's extremely contaminated soil was very high. Buildings and trees have a great historical value and they could not be harmed or destroyed.

A successful project that has developed an approach of gentle vacuum suction remediation that effectively removes contaminated soil adjacent to mature large trees, in slopes and near buildings worthy of protection. The soil was removed with great precision which allows removal of soil around tree roots or in unevenness of a rocky slopes.

The industrial history of Beckholmen began in the 1700s and all surfaces were heavy contaminated, mainly with heavy metals and polyaromatic hydrocarbons (PAH). There were measured concentrations of lead in the area up to 90,000 mg/kg DW and PAHs up to 800 mg/kg DW. The whole island of Heritage listed 20 old trees worthy of protection in the central area of the island.

Vacuum suction makes it possible to remediate sensitive areas such as parks with mature trees. The rescue project started August 2011 and was completed April 2012. The amount of soil vacuumed in the rooting area of 20 trees was 1 000 m3 and outside the rooting area 5 000 m3. The amount of soil removed and exchanged on the Island Beckholmen was over 300 000 ton.

    Total cost for excavation, replacement and renewal of the landscape of the Island was approx. 20 million Euros!

The approach of vacuuming contaminated soil can be applied in several places were trees are growing and therefore provides a great value for the ability to save old mature trees in many situations. The method makes it possible to remediate sensitive areas where traditional excavation would destroy hard re-created environments such as parks and forests with mature valuable trees.  

Presenter Information

    • Örjan Stål
      Orjan Stal has an independent Consultant firm VIOS and is also part time employed by the Swedish University of Agricultural Sciences. He is often enlisted as an expert at the major infrastructure projects in Scandinavia.

Presentation file information