The new sites are also expected to increase the local shellfish population and improve natural water filtration.
The trial, delivered in partnership with the University of the Sunshine Coast, OzFish, and Healthy Land and Water, began in 2023 with a single installation site.
Unitywater Executive Manager Sustainable Infrastructure Solutions, Mike Basterfield, said the expanded trial, now with three installation sites, included a total of 120 oyster baskets designed to attract and support shellfish.
“We’re pleased to expand this trial with two new sites downstream from Unitywater’s Murrumba Down Wastewater Treatment Plant,” Mr Basterfield said.
“The initial site achieved a reduction of 7.24 kilograms of nitrogen in the Pine River. This suggests that 154 reefs installed in an area the size of two rugby fields could completely offset the nitrogen from a treatment plant servicing 10,000 people.”
“As our region continues to grow, we are committed to exploring innovative, nature-based ways to complement the role of our treatment plants and keep our waterways healthy.”
OzFish Senior Special Projects Officer, Robbie Porter, said the custom-built reef baskets were designed specifically to restore fish habitat.
“Our mission at OzFish is to improve waterway health across the country so native fish species can thrive,” Mr Porter said.
“We’re excited to see how the new installations perform. For this next stage, we’ve introduced baskets of different shapes and sizes to understand which designs the shellfish prefer and which are the most durable.”
University of the Sunshine Coast marine ecology expert, Associate Professor Ben Gilby, said the trial was already indicating how effective shellfish can be as natural filters.
“The baskets have been overflowing with shellfish, particularly mussels, which only grow to the size of a ten-cent piece but are incredibly efficient at removing nutrients from the water,” Dr Gilby said.
“They absorb organic material as food and store nutrients in their bodies, preventing those nutrients from re-entering the river system.”
The expanded trial will run to 2028, and Unitywater will continue exploring opportunities for additional installation sites and new locations in the coming years.
