Tools for wood reprocessors to identify contaminated wood

Background

To date there has been no means to identify chemical treatments in wood waste that may often be invisible to the eye. As a result, the identification and segregation of chemically contaminated materials is not always optimal, thus presenting potential H&S issues, adding costs to the recycling process and potentially undermining recycled product quality.

End users, notably the panel board manufacturing industry, increasingly require verification that chemical contamination is removed. In response, WRAP has undertaken research to identify and develop technologies to enable the identification of cooper-based preservative treated wood waste by operatives at sites where waste is segregated and reprocessed. This has culminated in the successful production of chemical indicator solution formulas along with various application methods for the indicators.

This work builds on the earlier research by trialling the identification kits with the reprocessors’ site operatives. The trials aim to establish the best means of delivery as well as options for improving the kit before it is released for full production. The tools being trialled include a ring bound visual inspection guide to allow site workers to identify potential contaminated pieces of wood and a chemical colour-change toolkit.

Guides 

Chromazurol S Colour Indicator Technique for detecting copper contamination

This manual describes how to make, store and use a colour indicator, based on chromazurol, for the detection of copper-based preservative in wood waste streams for recycling. Examples of wood preservatives that contain copper include:

• CCA, copper-chrome-arsenate, which is the most commonly found wood preservative that contains copper, especially in waste wood streams. A wide range of formulations have been used in the past. CCA is now limited to a few industrial uses.
• CCB, copper-chrome-boron. An alternative to arsenic formulations.
• CCP, copper-chrome-phosphate. An alternative to arsenic formulations.
• Copper organics, these could contain the fungicides propiconazole and or tebuconazole or quaternary ammonium compounds. Other azoles are in development. These types of wood preservatives are becoming increasingly popular after the restrictions on the use of CCA were published.