The number of pentachlorophenol (PCP) treated poles being removed from service is increasing, but disposal options for this material are limited. Biological Degradation of the preservatives in spent poles, before disposal or reuse, offers a promising technique. The reduction of PCP in treated timber, after inoculation with PCP-degrading bacterial species, Rhodococcus chlorophenolicus and Flavobacterium sp, and the white-rot fungus Phanerochaete chrysosporium, was mornitored in solid substrate systems and in liquid culture suspensions. In solid substrate systems, there was no significant PCP degradation by the bacterial species under a variety of conditions. Under similar conditions, Phanerochaete chrysosporium transformed over 80% of the starting PCP concentration of 500 ppm to pentachloroanisole (PCA). In liquid culture suspensions however, mid-exponential phase Flavobacterium cells were able to degrade over 99% of the PCP in sawdust and wood chips due to the extraction of PCP from the timber as a water soluble salt. There were however no significant changes in the chlorinated dioxin components during this treatment.

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