Leachability and decay resistance of particleboard made from acid extracted and bioremediated CCA-treated wood

Abstract

Composite manufacturing appears to be one of the most suitable recycling options for chromated copper arsenate (CCA)-treated waste wood. However, in many applications it would be beneficial to remove much or all of the CCA from the wood prior to composite production. This paper evaluates the effect of remediation processes, namely oxalic acid (OA) extraction and Bacillus licheniformis fermentation, on leaching of copper, chromium, and arsenic from particleboard made from remediated wood particles and also investigates decay resistance of the particleboard. Oxalic acid extraction and bioremediation by B. licheniformis affected the chemical properties of wood particles and significantly increased leaching of elements from CCA-treated wood particles. The particleboard containing OA-extracted and bioremediated particles showed generally high leaching losses of remaining elements. Exposure of particleboards to decay fungi in soil block tests indicated that boards containing CCA-treated particles were most resistant to fungal degradation. Also, for a given board type, Gloeophyllum trabeum resulted in greater weight losses than Postia placenta and Trametes versicolor after 12-week exposure. We concluded that bioremediation of CCA-treated wood is a promising method of safely reusing treated fiber, although chemical extraction diminished the properties of composites prepared from this material.