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# A reed raft cleans Phillip Island's water
- URL: https://www.earthtoseanews.com/phillip-island-wetlands/
- Published: 2026-09-15T05:22:50.000Z
- Updated: 2026-09-15T05:22:50.000Z
- Description: On a treatment lagoon at Cowes, a floating garden the size of a tennis court and a half has spent two years quietly doing the work of machinery, and the numbers from the world first trial are in.
- Author: Nicole McMahon
- Tags: Innovations, All stories

Wastewater lagoons are the unglamorous end of every town, wide ponds where sewage settles and breaks down, breathing out carbon dioxide and methane as it does. At Westernport Water's treatment plant at Cowes on Phillip Island, south east of Melbourne, researchers from RMIT and CSIRO tried something gentler than a new machine. They floated a platform of 330 square metres on a lagoon holding fourteen million litres, planted it with three natives, common reed, jointed twig rush and marsh club rush, and let the roots hang down into the water. Over two years the plants and the microbes living among their roots took up nutrients and changed the chemistry of the pond. Carbon dioxide from the lagoon fell by up to 36 per cent, methane by up to 66 per cent and nitrogen by 18 per cent, which is the difference between a pond that leaks warming gases and one that behaves more like a wetland.

Dr Lukas Schuster, a research fellow at RMIT's Centre for Nature Positive Solutions, is first author of the paper, with Dr John Awad of CSIRO and the programme led by RMIT's Dr Martino Malerba, and Westernport Water's managing director Dona Tantirimudalige has the quiet pride of a small utility that got to be first at something. What makes it lovely is that it is a garden: no power, no chemicals, plants that belong to the coast, and a habitat where there was only water before. Next the rafts go inland, to farm dams on the Bass Coast with Melbourne Water and the local Landcare network, where Kernot farmer Camilla Graves is among the first to try one. Anyone who has watched reeds move in a breeze knows how it looks. Now there is a number for what it does.

### Sources and links

Our short take: the full story is by Jack Colantuono, Zaida Glibanovic and Mim Hook for ABC News (12 September 2026); the research is published in the Journal of Environmental Management and described in RMIT's release of 24 August 2026\. Photograph: Pi.1415926535, CC BY-SA 4.0.

- [World first trial on Phillip Island discovers floating wetlands can cut emissions](https://abc.net.au/news/2026-09-12/floating-wetlands-slash-wastewater-greenhouse-gas-emissions/107075464) ABC News, 12 September 2026.
- [Constructed floating wetlands cut greenhouse gas emissions from wastewater lagoons](https://doi.org/10.1016/j.jenvman.2026.130663) The paper, Journal of Environmental Management, 2026.