Ultrasound combats algae growth

In collaboration with water industry organisations including SA Water, the researchers are starting a three-year project to find the best process for using ultrasound in large volumes of water to combat this worldwide water quality problem.

Chief investigator Dr Carl Howard, from the university’s School of Mechanical Engineering, said researchers will be testing different amplitudes and frequencies of ultrasound.

’We’ve already shown in laboratory tests that ultrasound is effective at neutralising blue-green algae,’ said Dr Howard.

’We know it works but we don’t yet know the best frequencies, amplitudes and duration for the most effective, economic and efficient process.’

Blue-green algae (or cyanobacteria) can affect health and causes other water quality and environmental problems when it accumulates and forms ‘blooms’ in fresh water. It is currently controlled by the application of chemical treatments.

Dr Howard said ultrasound, at high amplitudes, is used for treating sewage and in other chemical processes but hasn’t been practical for fresh water treatment. Ultrasound at high amplitudes breaks down the cell walls of the blue-green algae, releasing toxins into the water.