Green trench trial recognised as a win-win for innovation and sustainability

Greater Western Water's (GWW) innovative Sunbury backfill trial has been recognised at the Green Gown Awards Australasia, which celebrate sustainability excellence across the tertiary education sector in Australia and New Zealand.

Winning the 'Leading the Circular Economy' category, the award acknowledges the project's collaborative approach to advancing sustainable construction practices with the use of recycled materials to backfill trenches.

The award highlights the partnership between GWW, Victoria University (VU), Sustainability Victoria, and Ground Science, organisations leading the way in developing infrastructure solutions that deliver long-term benefits to communities.

The trial involves backfilling trenches at GWW's Sunbury depot using a mix of recycled materials, including crushed concrete, glass, plastic, and rubber from tyres. These materials have been lab-tested by VU and are undergoing a 14-month monitoring period to assess their durability under heavy truck loads.

Kessia Thomson, GWW's General Manager of Strategy and Partnerships, said the trial could reshape how the construction industry approaches trench backfilling, with major implications for sustainability and cost-efficiency.

"Projects like this pave the way for long-term environmental benefits by turning recycled materials into viable products and supporting a circular economy," she said.

By replacing traditional materials like crushed rock, sand or gravel, which are increasingly scarce or higher in cost, the project helps conserve natural resources and diverts waste from landfill. It has already demonstrated environmental impact, saving more than 280 tonnes of CO₂ emissions per 100 metres of trenching.

"This trial offers a cost-effective way to backfill trenches and is shifting industry expectations of what's possible in sustainable infrastructure. We see this technology strengthening local industry, both within our service area and beyond," Thomson added.

The project first won its category in the Victoria University Vice-Chancellor's Awards, which led to its nomination as a finalist for the Green Gown Awards. It was also recently listed as a finalist for the Victorian branch's Australian Water Association (AWA) awards, further recognising its contribution to sustainable innovation in the water sector.

The Green Gown Awards, delivered by Australasian Campuses Towards Sustainability (ACTS), are supported by the United Nations Environment Program and are considered the leading sustainability awards for the region's education sector.

Project partners on site during the backfill trial in Sunbury.

Media enquiries
0417 459 575
media@gww.com.au