Search
Log in
Back to News and Media

Exploring new solutions for one of New Zealand's toughest waste challenges

Hero

Most people don't think twice about an old fence post or a weathered deck board.

But when treated timber reaches the end of its life, it becomes one of the most complex materials in New Zealand's construction and demolition waste stream.

Commonly used in framing, fencing and outdoor structures, CCA-treated timber contains copper, chromium and arsenic. While these compounds help protect timber during use, they create significant challenges once the material is removed from a building or demolition site.

Unlike untreated timber, treated timber cannot simply be repurposed into standard wood products. It also faces increasing scrutiny due to the environmental risks associated with improper handling and disposal.

At the same time, construction and demolition activity continues to generate increasing volumes of treated timber across New Zealand, highlighting the need for safe, practical and sustainable long-term solutions.

For WM New Zealand, challenges like these present an opportunity to think differently.

Through its Circular Services team, WM New Zealand is exploring a range of potential pathways that could help improve how treated timber is managed in the future. While there is no single solution, the work underway aims to better understand which approaches can deliver the best environmental and operational outcomes.

National Processing Manager Hooman Javaheri says the goal is to identify practical solutions that support both industry needs and broader sustainability ambitions.

"There's no silver bullet when it comes to treated timber," says Hooman. "The future is likely to involve a mix of solutions, with different pathways suited to different timber types, contamination levels and end markets."

The Circular Services team is currently exploring a range of options, including:

  • Chemical and thermal treatment technologies that can remove or neutralise hazardous compounds.
  • Producing fuel pellets for cement kilns, where high temperatures can safely destroy contaminants.
  • Working with licensed facilities that can process treated timber under strict emissions controls.
  • Investigating specialist offshore recovery pathways that operate under compliant treatment and export frameworks.

For WM New Zealand, exploring solutions for difficult waste streams is an important part of supporting a more circular economy and helping reduce the amount of material sent to landfill.

While the industry continues to search for the best long-term approach, WM New Zealand remains focused on understanding what works, testing options carefully and building partnerships that can support better outcomes for the future.

Because creating a more sustainable future starts with tackling the challenges that don't yet have easy answers.

Our Sustainability Stories