About 1.3 Mio t/a (30%) of post-consumer wood are energetically
recycled in small-scale combustion plants. This amount
includes waste wood A I and harvested timber products like particleboards
without wood preservatives and PVC, categorized as A II,
according to the German Waste Wood Act (German Government,
2003). The contamination level of this material is low, which
makes it suitable as a secondary resource in products. The largest
share of post-consumer wood (5 Mio t/a = 70%) can be classified
as A III, which is a mixture of untreated, treated and contaminated
waste wood. A separation into fractions of this amount for material
recycling (A I–A II) and energy recovery (A III–A IV) would presume
an intensified and cost-intensive separation process considering
the prohibition of diffusion of hazardous substances through recycling
activities as outlined in the German Waste Management and
Product Recycling Act (German Government, 2012) and the European
Waste Directive 2008/98/EC (European Commission, 2008).
Automated computerized sensor sorting based on detection processes
like near infrared spectroscopy (NIR), ion mobility spectrometry
(IMS) and X-ray-fluorescence analysis are promising
techniques for the cascading use of wood (Meinlschmidt et al.,
2013), but are not used up to now in large scale post-consumer
wood flows.