Clausen Carol
USDA Forest Service, Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI 53726-2398, USA.
Waste Manag. 2004;24(4):401-5. doi: 10.1016/j.wasman.2003.11.008.
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.
在本研究中，对一种处理铬酸铜砷酸盐（CCA）处理木材的修复工艺的三种可能改进方法进行了评估。该工艺包括两个步骤：用草酸提取木纤维，然后用地衣芽孢杆菌CC01进行细菌培养。草酸提取步骤的三种潜在改进方法是：（1）多次重复使用草酸进行提取；（2）改变草酸与木材的比例；（3）使用非商业来源的草酸，如黑曲霉，它作为代谢副产物产生草酸。多次重复使用草酸进行提取可去除大量的铜、铬和砷。增加木材与酸的比例会导致金属去除量稳步下降。黑曲霉从CCA处理过的木材中去除了适量的铜、铬和砷。虽然黑曲霉有效，但培养基成本可能会抵消任何益处。对于两步法工艺，用商业草酸进行重复提取似乎是测试过的最具成本效益的方法。
