The Port of Gothenburg is planning to make use of contaminated clay from the seabed to build a new freight terminal at the outer port area at Hisingen.
It will cover 220,000 square metres and be built using clay spoils from the Göta Älv river, taken up as part of routine dredging to maintain the river depth.
Dredging spoils in the river are contaminated by a variety of substances, including TBT, tributyltin, an environmental toxin that can disrupt hormone levels.
Until 2008, it was included as an antibiocide in antifouling paints used on the hulls of ships and boats.
To ensure the spoils can be enclosed safely without seeping into the surroundings, exhaustive trials are being conducted.
Eduardo Epifanio, Project Manager at the Port of Gothenburg, said: “There is no suitable landfill site for contaminated spoil volumes of this size.
“This is a good way of using the spoils and at the same time helping to clean up the river.”
The method has already been tested in the laboratory.
Field trials have been conducted to test two different combinations of materials and will continue until Easter which is when the results will be evaluated.
The first method involves mixing the spoils with cement and slag, and the other involves mixed the spoils with cement, slag and fly ash – a considerably cheaper and eco-friendlier alternative.
Epifanio added: “It worked well in the laboratory and now it will be tested on a larger scale. It is important to ensure that no environmental toxins escape into the water and that the strength and durability specifications are met.”
