Repurposing preservative-treated timber and engineered wood products at end-of-life: a circular approach

Summary

Objective

Wine Australia has partnered with the University of the Sunshine Coast and other Industry Partners under the Federally supported Cooperative Research Centres-Project (CRC-P) Program to collaborate on a project on the reuse/recycling of treated and engineered timber products. The goal of the project will be to deliver a process/program that will help timber users select the most appropriate strategy for their respective material. The aim is to develop circular economy-based solutions for timber products previously considered as waste.

The objectives of the project will be:

1. Develop disposal volume estimates by material category and region/State.
2. Identify potential risks and regulatory constraints associated with collection, transport, and reuse of each material and propose solutions.
3. Develop transportation/collection strategies by material and location.
4. Provide costed re-use options to timber users based on their location and type of timber waste.
5. Review existing technologies for reuse/recovery to identify/fill knowledge gaps.
6. Produce a selection tool for reuse/recycling where users input treatment/commodity data within their region to identify opportunities/hurdles for each potential strategy.
7. Deliver at least one regional demonstration take-back program that encompasses the collection, sorting, and reuse of a single product.

Vineyard posts have been selected as the pilot product and can serve as the template for similar efforts in other regions with vineyard posts or potentially with other materials.

Background

Vineyard posts are widely used across Australia because of their excellent material properties and low cost. These posts are typically low durability pine species that must be preservative treated to provide the expected service life. Nearly all vineyard posts are treated with chromated copper arsenate (CCA), although some are also treated with a new creosote-like formulation. CCA is an exceptional preservative in terms of longevity and performance, but eventually, posts must be replaced either through gradual loss in preservative protection or breakage during harvesting. At this point, the very metals that made CCA treated timber such an asset pose logistical challenges especially with regard to transport and disposal. CCA treated timber can be landfilled, but it cannot be burned except in specially licensed facilities. Transport can also be regulated, depending on the state. As a result, many vineyard owners accumulate large stocks of broken posts with few avenues for reuse.

Sector benefits

All the information gathered from the project will be used to develop a program where a producer or user of treated and engineered timber products can enter information on the treatment, volumes produced, and region and receive options for reuse or disposal with estimated costs and potential hurdles so that they can select the most appropriate approach for their materials.