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Contributing to the circular economy

In 2016 Boskalis and HVC, the largest non-commercial waste collection company in the Netherlands, opened the world’s first bottom ash washing plant. The plant recycles incinerator bottom ash, a by-product of the incineration of household waste in waste-to-energy plants.


The Netherlands has twelve waste-to-energy plants and they produce approximately two million tons of bottom ash annually. For many years this contaminated bottom ash could only be used as a building material in the Netherlands if stringent conditions were met, with the material having to be sealed in sheeting to prevent pollutants leaking into the environment. However, the use of incinerator bottom ash required such an intensive and expensive management program by the Dutch government that it will be banned.


Boskalis Environmental developed its own patented separation and flushing technology and offers a unique sustainable method of cleaning incinerator bottom ash. Once processed, almost all of the bottom ash is suitable for re-use as a raw material, allowing Boskalis to contribute to the circular economy.

The mineral fraction, consisting of sand and granulate, will be used as a freely applicable building material in Boskalis’ civil engineering works while the valuable and rare metals can be marketed as commodities by the waste-to-energy plants. Haico Wevers, director of Boskalis Environmental

At the beginning of 2017 Boskalis announced, together with Inashco, that it will process all bottom ash produced by Attero’s waste-to-energy plants in the Netherlands for a period of ten years. A new state-of-the-art plant at Nauerna in the Port of Amsterdam area will process the bottom ash.

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