Floating wetlands slash greenhouse gases from wastewater lagoons in pioneering Victoria trial
A two-year trial on Phillip Island showed that a 330-square-metre floating wetland reduced lagoon emissions of CO₂, methane and nitrogen by up to 36%, 66% and 18% respectively.
Over two years, a collaborative trial on Phillip Island deployed a 330-square-metre floating platform planted with native reeds and sedges into a wastewater lagoon holding roughly 14 million litres of effluent. Led by RMIT’s Lukas Schuster together with Westernport Water and CSIRO, the experiment continuously measured greenhouse gases using solar-powered sensors and found reductions of up to 36 % in carbon dioxide, 66 % in methane and 18 % in nitrogen versus a control lagoon.
The plant roots foster microbial communities that break down organic matter, while the system also captures nutrients, pollutants such as PFAS and offers habitat for birds. Researchers highlight that the technology can be retrofitted to existing open lagoons without extensive construction, and water companies have shown interest in scaling up. The concept is now being trialled in farm dams across the Bass Coast, with farmer Camilla Graves noting improvements in water quality and protection for ducks. Future work will explore more sustainable floating materials and broader deployment possibilities.
Why it matters
Shows a low-cost, nature-based way to cut wastewater-treatment emissions, supporting climate and water-quality goals.
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