Using microbes to starve algal blooms

Vital research aiming to determine cost-effective and efficient treatment to reduce the incidence of toxic algal blooms in Adelaide’s Torrens Lake is happening 17 kilometres away from the site, at an experimental biological filtration facility at Flinders University.

Flinders Bioremediation has teamed with UniSA and water engineering company United Utilities as partners in a consortium appointed by the Adelaide City Council to investigate a technology to address persistent algal bloom problems in the lake.

With the support Flinders University scientists, Flinders Bioremediation have set up a pilot plant trial using 70,000 litres of Torrens water to provide base-line data for a full trial conducted by the consortium that is set to commence on the banks of the Torrens Lake in late February.

Flinders Bioremediation project manager Dr Jon Varcoe said the method to be trialled is aimed at reducing suspended material and nutrients in the lake water by a biological process known as biofiltration. The Torrens Lake water will be pumped through a system of foam pads populated with micro-organisms, which should result in improved water quality.

“If sufficient removal of nutrients from the water by the action of the bio-filter microbes can be achieved, this would limit algal and cyanobacterial growth,” Dr Varcoe said.

“This established aquaculture technology is being trialled on a scale not previously attempted to investigate its suitability to treat Torrens Lake water.”

The work at Flinders involves aquaculture and biofiltration researcher Dr James Harris, and utililises an experimental filtration facility attached to the School of Biological Sciences.

“The scale model at Flinders will provide the larger on-site filtration trial with information as to effective pumping rates and likely sludge development rates,” Dr Varcoe said.

The off-site trial also allows the researchers to modify and control the test conditions and water quality parameters such as the nutrient load of the water prior to treatment.

“If the trials, both here and on the Torrens, show the treatment system to be effective, then it is envisaged that the optimum system will be scaled up on the banks of the Torrens to treat the full volume of the lake,” Dr Varcoe said.

In a bonus for Flinders University, the Torrens water used in the trial will be recycled after treatment to top up the campus’s central lake and irrigate the University’s sports-fields.

The project is scheduled to run to July 2008.

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