Under the so-called Kringbouw project in the Netherlands, which aims to close the material loop in the construction sector, researchers at the Delft University of Technology in the Netherlands have studied advantages and disadvantages of different separation techniques: wind screens, ballistic separators, inclined screens and colour separation.

International Wastenews, Waste Centre Denmark no. 1, 2005 reports that the study focused on a combination of dry separation and automatic separation. The conclusion was that it is not possible to say that one technique is superior to others, but that it depends on a weighing between different factors such as economy, capacity, markets for the product, need for coordination with already existing treatment plants and whether it is expedient to classify a given fraction narrowly.

Against this background, the study forms the basis for future tailor-made techno-economic analyses of specific treatment plants. In connection with the follow-up on the project it is planned in the coming years to make full-scale pilot tests for demonstration of automatic separation of construction and demolition waste