Locals and business owners are calling for the Adelaide City Council to trial an emerging technology that could help end regular closures of the Torrens Lake due to bacteria.
The current closure — due to enterococci bacteria — is the third time this year where parts of the River Torrens has been made inaccessible to users, including rowing clubs and boat operators.
High levels of E. coli bacteria infiltrated the lake earlier this year as thousands of dead fish were seen on its banks.
Singer-songwriter and local resident John Schumann is leading a charge to clean up the river with 'nanobubble' technology, which has been previously tested in New South Wales.
He has made a submission calling on the council to test the technology in the lake.
"It's supposed to be the centrepiece of Adelaide, and it doesn't have to be like this, and that's my frustration," Mr Schumann said.
"I live nearby and I use the path around the lake and through the parklands.
What is 'nanobubble' technology?
Nanobubble technology generates microscopic bubbles using gases like oxygen and ozone, then mixes them throughout water bodies to help break down chemical contaminants and also reduce microbial growth.
Dr Arash Zamyadi is a senior lecturer of Civil and Environmental Engineering at Monash University and researches nanobubble technology in Australia.
"We use a really, really low amount of energy to diffuse the solution, which is the nanobubble," said Dr Zamyadi.
"That has the capacity to break down the contaminants, both the microbes, the pathogens, and the chemicals like the toxins."
It was recently used in a year-long trial by Wagga Wagga City Council in NSW to remediate Lake Albert.
The technology was put forward by Council Charles Sturt to tackle the algae in West Lakes last year but was opposed by SA Water and the state's Environmental Protection Authority, due to a lack of scientific evidence and uncertainty of its impact on wildlife.
Dr Zamyadi understands authorities' hesitation.
"It's a very new, innovative technology, which definitely needs more feasibility studies and understanding its performance," said Dr Zamyadi.
"I totally understand that there is concern from the regulators, from the authorities, from the managers, from the engineers, and I believe that's the role of the science [to perform] independent evaluation and assessment.
"When you look at the case of Lake Albert in Wagga Wagga, there was no report of loss of any other form of aquatic life, it really targets the algal blooms and the associated contaminants."
Trial to be discussed by council
Closures of the Torrens Lake restrict access to rowing clubs and boat operators like Tony Shuman, who operates cruising riverboats.
He supports the push to trial nanobubble technology in the river.
"Let's try something rather than nothing," Mr Shuman said.
In a statement, the Adelaide City Council said it was "in discussions with other councils and government agencies about ways to improve the management of the River Torrens system and catchment area".
"The proposed nanobubble technology trial is a separate matter which will be discussed by elected members in coming weeks," the statement said.
Deputy Lord Mayor Carmel Noon is supportive of the trial and said it was council's responsibility to look after the Torrens Lake.
"I'm very adamant that we have a major role here to be able to mitigate this," she said.
"So I'm wanting a trial. It would be amazing that we could actually stop the closures of this part of the river that affects so many businesses and livelihoods."
If the trial proceeds, nanobubble technology would be installed between the Torrens Weir and Albert Bridge at Frome Road.
Cr Noon said she hopes to expand it further along the river and across multiple council areas if a trial were successful.
