The U.S. Army and the University of Adelaide in Australia have both discovered how to purify water using sound waves.

According to a recent article, the U.S. Army is funding a project that uses acoustic waves to trap and remove bacterial spores from water. The spores can then be analyzed using spectroscopy, potentially offering a low-cost, remotely available method for monitoring water supplies.

A similar project is being conducted over the next three years in Australia at the University of Adelaide, but with blue-green algae, instead of bacteria. Researchers will test different frequencies and amplitudes of ultrasound waves to control algae in Australia’s freshwater supplies. At high amplitudes, ultrasound breaks down the cell walls of algae, releasing toxins into the water. The researchers will be using ultrasound at low amplitudes to neutralize and immobilize the algae without releasing its toxins into the water. This process resembles that of UV water filtration, which renders microorganisms inactive in water. Since algae are a growing water quality problem worldwide, the implications of the study are far-reaching.