The German "Altholzverordnung" (Waste Wood Ordinance) provides for a division into two sub-groups, referred to as industrial residual wood and waste wood. The former comprises leftovers - such as, for example, sawdust - from wood processing, wood machining or the wood-based materials industry which are only subject to the regulation if they cannot be used within the company or marketed as a by-product and must therefore be disposed of.
The latter were formerly products and can be roughly divided in their origins into packaging materials, demolition waste wood, wood from the construction industry, wood from urban areas and wood from industrial or commercial activities. This is of particular importance because as a rule, the Waste Wood Ordnance provides for an allocation of the resulting waste wood determined by the place in which it occurs and its intended use. The amount of waste wood in Germany was, according to data from the Federal Statistical Office, approximately 11 million tonnes in 2010. Since about 10% was declared as hazardous waste or A IV timber, it can be assumed that around 10 million tonnes of materially-usable waste wood resulted in the categories A I to A III.
Currently, the material usage of waste wood in Germany takes place primarily in the wood-based materials industry for the production of particle boards and fiber boards. Whilst the proportion of recycling wood in Germany had remained at around 20% for a number of years, it rose in 2010/2011 to 33%. In the comparable countries of Great Britain and Italy, the proportion reached 55% and 89% respectively.
Sources of raw materials which have, until now, only been insufficiently utilized should now be developed - for example, the wood categories A III and A IV, which are classified under the Waste Wood Ordnance as contaminated. These wood wastes additionally contain plastics such as PVC, wood preservatives and paints which contain heavy metals. Even in this contaminated lignocellulosic material there is a not inconsiderable amount of recyclable timber which needs to be recovered through appropriate separation and sorting processes.
In order to comply with legal limits during usage, complex chemical analyzes such as GC-MS, ICP-OES and IC have been necessary up until now.
The goal is the development of a rapid detection method, with the help of which unambiguous sorting criteria can be developed which allow the determination of whether a waste wood is still materially or only thermally recyclable. Near-infrared (NIR) spectroscopy has the potential to replace a part of the elaborate laboratory analyzes.