Properties of structural panels fabricated from bioremediated CCA-treated wood: Pilot scale

Particleboard and flakeboard panels were fabricated from remediated CCA-treated southern yellow pine. Treated wood, flaked or comminuted into particles, was remediated in 12-kg batches using oxalic acid extraction, followed by bioleaching with the metal-tolerant bacterium Bacillus licheniformis. Remediation resulted in removal of 80 percent Cu, 71 percent Cr, and 89 percent As for the particulate material and 83 percent Cu, 86 percent Cr, and 95 percent As for the flaked material. Particleboard and flakeboard panels were evaluated for modulus of elasticity (MOE), modulus of rupture (MOR), and internal bond (IB) strength. Particleboard made from remediated material with 10 percent urea-formaldehyde resin showed an 18 percent reduction in MOE, 47 percent reduction in MOR, and 37 percent reduction in IB strength compared to comparable panels made from untreated wood. Flakeboard prepared from remediated material with 5 percent phenol-formaldehyde resin showed insignificant differences in MOE and MOR, and a 16 percent increase in IB strength compared to panels consisting of untreated wood. Properties of remediated particleboard were significantly diminished compared to those of panels made with untreated wood. MOR and MOE of remediated flakeboard were comparable to that of untreated material, but IB strength was increased. Flake geometry and type of resin, as well as differences in surface area and metal removal between the two wood geometries, may all account for variations in panel properties.