Improving the two-step remediation process for CCA-treated wood: Part I. Evaluating oxalic acid extraction.
In this study, three possible improvements to a remediation process for chromated-copper-arsenate- (CCA) treated wood were evaluated. The process involves two steps: oxalic acid extraction of wood fiber followed by bacterial culture with Bacillus licheniformis CC01. The three potential improvements to the oxalic acid extraction step were (1) reusing oxalic acid for multiple extractions, (2) varying the ratio of oxalic acid to wood, and (3) using a noncommercial source of oxalic acid such as Aspergillus niger, which produces oxalic acid as a metabolic byproduct. Reusing oxalic acid for multiple extractions removed significant amounts of copper, chromium, and arsenic. Increasing the ratio of wood to acid caused a steady decline in metal removal. Aspergillus niger removed moderate amounts of copper, chromium, and arsenic from CCA-treated wood. Although A. niger was effective, culture medium costs are likely to offset any benefits. Repeated extraction with commercial oxalic acid appears to be the most cost-effective method tested for the two-step process.
Clausen
Carol
C
USDA Forest Service, Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI 53726-2398, USA. cclausen@fs.fed.us
D001149:Arsenates / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D001151:Arsenic / Q000302:isolation & purification; D001234:Aspergillus niger; D001407:Bacillus; D001673:Biodegradation, Environmental; D002857:Chromium / Q000302:isolation & purification; D003300:Copper / Q000302:isolation & purification; D003362:Cost-Benefit Analysis; D004787:Environmental Pollution / Q000517:prevention & control*; D019815:Oxalic Acid / Q000737:chemistry*; D014934:Wood
D001149:Arsenates; D002857:Chromium; C040890:chromated copper arsenate; D003300:Copper; D019815:Oxalic Acid; D001151:Arsenic