Technical information

1. Chromated copper arsenate (CCA)-treated wood as a critical material in infrastructures has been widely used for better performance against rotting and weathering over long periods of time. Currently, a large amount of CCA-treated wood has become waste material, and the disposal of these treated wood products poses serious problems. However, energy recovery of CCA-treated wood waste is difficult due to the toxic materials that are released during combustion.
   

1. An antiseptic element should be efficiently extracted from the waste to form a cheap solvent. Copper, chromium, and arsenic contained in the extracted material are to be separated and recovered individually. The procedure involves precipitation and adsorption methods using a protonated manganese oxide.
   

1. The extracted material can be reused and recycled by this new method. The treatment cost of the waste will be decreased overall. Copper, chromium and arsenic were successfully extracted first from treated wood powder by an acid treatment to a contaminant solution.This solution was further extracted by precipitation and adsorption processes, including a method with the protonated manganese oxide.
   

1. The treated wood waste was, therefore, effectively cleaned of harmful contaminants to reach effluent treatment standards in an economical manner as well as recovering two valuable metals, copper and chromium, for recycling and reuse .
   

Fig. 1 Waste of preserved woods in USA

  

REFERENCES

H. Koyanaka, Flotation method for treatments of radioactive waste water, and safety treatment of preservative treated wood wastes, The 23rd Symposium, Separation refinement technology for recycling of the earthquake disaster waste，The Resources Processing Society of Japan, Sept. 16, Tokyo, (2011)

6. F.Kurosaki, H. Koyanaka, T. Hata and Y. Imamura, Macro porous carbon prepared by flash heating of sawdust, Carbon, Vol. 45, pp. 671-673, (2007)
   

Kakitani T., Hata T., Kajimoto T., Koyanaka H., Imamura Y., Characteristics of a bioxalate chelating extraction process for removal of chromium, copper and arsenic from treated wood, Journal of Environmental Management, Vol. 90, No. 5, pp. 1918-1923, (2009)

Hata, T., Koyanaka. H., Hwang, W. -J. EXTRACTION AND SEPARATION OF ARSENIC AND CHROMIUM FROM CHROMIUM COPPER AND ARSENIC TREATED WOOD USING PROTONATED MANGANESE OXIDE, Hazardous Waste Management, 1st International conference, Chania-Crete, Greece, Oct. 1-3, (2008)

Kakitani T., Hata T., Katsumata N., Kajimoto T., Koyanaka H., Imamura Y., Chelating extraction for removal of chromium, copper, and arsenic from treated wood with bioxalate, Environmental Engineering Science, Vol. 24, No.8, pp. 1026-1037, (2007)

JP PATENT 5039953・2006・2・20