Technologies for the Management of Wood Waste Containing Metals-Based Preservatives

IRG/WP 05-50224-16

H M Solo-Gabriele, T G Townsend

Disposal of the metals from preservative treated wood can occur through two general strategies: “removal and confinement” or “dilution”. The acceptability of each of these two choices is typically dictated through the disposal regulations of a particular region. A considerable amount of research has been conducted to develop new and innovative “removal and confinement” technologies for treated wood waste. These technologies include disposal through bioremediation processes (including use of bacteria and fungi), chemical extraction processes, electro-dialytic treatment, and alternative thermo-chemical processes. “Removal and confinement” strategies will likely require adequate sorting and separation of the waste prior to disposal for mixed waste streams. “Dilution” strategies, which are typically less costly than “removal and confinement” technologies, include the management of treated wood through the regular solid waste stream. In some cases recycling of the wood waste may be allowed for certain re-use and recycling applications. In most regions, management of treated wood as regular solid waste will likely occur through either landfill disposal or through incineration at solid-waste processing facilities. Disposal through incineration will require air pollution control devices to minimize volatile releases and as a result the majority of the metals will accumulate within the ash. If the treated wood waste is co-disposed with other wastes there may be sufficient dilution to provide for a non-hazardous ash, which can be landfilled. Over time disposal of metal-treated wood in landfills (as either unburned wood or as ash) will likely result in the release of the metals from the wood resulting in higher metals concentrations in leachates from landfills. Whether or not this leachate is treated will depend upon whether or not there is sufficient dilution to maintain metals concentrations below certain regulatory thresholds. Thus the choice of suitable disposal options for wood treated with metal-based preservatives is dictated highly by the regulations of a particular region. These regulations are a reflection of the community’s “dilution capacity” and the balance between economics and allowable levels of environmental contamination.


Keywords: Disposal, treated wood, CCA

Conference: 05-02-07/08 Cannes-Mandelieu, France


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