Emissions From Kiln Drying of Pinus radiata Timber: Analysis, Recovery, and Treatment

Abstract

The effect of drying schedules was investigated on the volatile organic compounds (VOCs) emission from kiln drying of Pinus radiata timber. An enclosed drying system has been invented to recover the VOCs emission and the heat in the drying medium. A new technology, called TOCKDOST, was also developed for treatment of the emission condensate for safe discharge to the environment. The condensate had high chemical oxygen demand (COD) of 256–280 mg l⁻¹, high total organic carbon (TOC) of 56–69 mg l⁻¹, and low pH of about 3.7, and thus required treatment before being discharged to the environment. After numerous trials, it has been found that the most effective treatment was to use Fenton's reagent followed by activated carbon adsorption. With optimum treatment conditions, the average COD was reduced by 93%, TOC was reduced by 87%, and pH was increased to about 6.

Keywords:

• Condensate treatment
• Emission recovery
• Fenton's reagent
• Kiln drying
• Pinus radiata timber
• Volatile organic compounds (VOCs)

ACKNOWLEDGMENTS

The author would like to thank John Forgarty Engineering Ltd. for construction and setting up of the new, enclosed drying system; Professor Tieling Xing of Suzhou University, China, and Ms Sharon Lin, former student of this department, for assistance with the condensate treatment.