Dr Tripti Singh
Australia’s drive towards sustainability and a circular economy has heightened the focus on recycling timber, a renewable, natural resource, ideal for the circular bioeconomy. Currently, 60% of used timber ends up in landfill, with the remainder mostly burnt as fuel. Source: Timberbiz
Using timber over multiple life cycles ensures long term carbon sequestration and increased resource efficiency. Preservative treated timber and engineered wood products (EWP) provide additional advantages; the life of treated timber is extended by more than 10 times and EWP increases use of wood resources, structural integrity, and size.
These wood products directly contribute to carbon neutrality and will aid the transition to a net positive future. However, while beneficial during their service life for their durability and strength, these materials pose significant challenges for reuse and recycling at end-of-life due to chemical treatments and adhesives.
The Timber Circularity Project is a three-year industry-funded initiative led by the National Centre for Timber Durability and Design Life (NCTDDL) at the University of the Sunshine Coast (UniSC).
The project has been running for just over a year with support from Forest and Wood Products Australia (FWPA) and key industry stakeholders including Australian Forest Products Association (AFPA), Wine Australia (WA), Engineered Wood Products Association of Australasia (EWPAA), Frame & Truss Manufacturers Association of Australia (FTMA), Koppers, Hexion and Azelis.
Professor Tripti Singh, NCTDDL Director, overseas a team of individuals working on the project including Dr Penelope Mitchell, who is working full time as Project Leader, Dr Martin Strandgard, Dr Melanie Harris, Dr Mohammad Reza Ghaffariyan, Dr Nami Kartal, and Associate Professor Sanjeev Kumar Srivastava.
The project addresses the challenges of recycling treated timber and EWP, and some significant advances have already been made in quantifying and analysing the condition of end-of-life resources nationally.
The team has conducted site visits and surveys and are currently geospatially mapping resource volumes by location and type. Regulatory challenges have also been assessed and a draft report completed, which is aiding the development of Information sheets designed to aid industry advocacy with regulators. Industry insights to align key messaging for regulators will be obtained during an upcoming workshop.
Logistics, which are critical for integrating treated timber into a circular economy, are also being analysed, and an initial case study has been undertaken to compare different scenarios for collection, loading, transport, and chipping of resources for use in new applications.
“Recycled wood fibre will be required for existing products such as particleboard as well as emerging products including low-carbon concrete blocks and wood-plastic composites,” said Dr. Penelope Mitchell, project leader.
“However, the presence in wood products of glues and chemical treatments such as copper chromium arsenic (CCA), complicates recycling efforts.”
CCA treated timber, comprising 30% of treated timber in Australia, poses specific challenges due to potential leaching of chemicals and heavy metals when recycled. Research to extract these substances effectively and economically has been conducted over the last few decades.
“Research into extraction methods using chemical and biological means has shown promise,” continued Professor Tripti Singh, NCTDDL Director. “Yet, scaling these methods to meet regulatory standards and managing resultant toxic waste remain significant hurdles.”
Although high extraction rates are possible in laboratory scenarios, scaling up is costly and not currently viable under current economic models. There is also the issue with the resultant hazardous extractants produced by any remediation methods.
Clean timber will be required for many applications, particularly if the timber is used in concrete or other porous applications where leaching may occur. While the project team are continuing to investigate viable remediation options, other avenues for CCA treated timber are required immediately if the 2030 Government target for a circular economy are to be met.
The Timber Circularity team has undertaken an assessment on potential solutions for Australian end-of-life timber resources and ordered them in a hierarchy from reuse through to energy production.
The solutions have been mapped against considerations including ecological impact, technical issues, scale, and economics. After analysis of the solutions and subsequent site visits, three distinct opportunities have been selected to further as pilot studies across different states in Australia. Undertaking different pilots in three states will allow the evaluation of the regulatory landscapes, logistical requirements, and market potential for recycled timber products. These pilot studies are crucial for understanding the feasibility of large-scale implementation and identifying scalable solutions.
“With the Australian Government’s target of achieving a circular economy by 2030, it’s essential that we find sustainable pathways for all timber,” highlighted Dr Mitchell. “This project not only addresses environmental concerns but also explores the economic viability, logistics and regulatory challenges for recycling timber into higher-value products.”
The project’s comprehensive approach includes:
- Quantifying available end-of-life timber resources and their condition
- Mapping geospatial data to visualize resource distribution
- Addressing state-by-state regulatory challenges
- Analysing logistics and infrastructure needs for timber recycling
- Developing a hierarchy matrix for evaluating recycling solutions
- Undertaking pilot projects and documenting case studies.
“By converting challenges into opportunities, the Timber Circularity project aims to demonstrate how treated timber can play a pivotal role in Australia’s circular bioeconomy,” concluded Professor Singh.
