The absence of commercial facilities to recycle or recover value from wood treated with metal-based wood preservatives at the end of its service life is one of the most significant negative points in the generally positive life cycle analysis of treated wood. An experiment was initiated to determine whether wood treated with carbon-based preservatives could be degraded by composting without residual preservative contamination. After one year the concentration of triazoles remained high, while the concentration of DDAcarbonate was greatly reduced.
This report describes the depletion of carbon-based actives from compost mixtures after a further six months of storage. Triazoles remained at high concentrations in the wood, while the concentration of DDAcarbonate was reduced. Overall, composting wood treated with carbon-based preservatives, under the conditions present in this study, was neither wholly effective nor efficient in breaking down these preservatives.