Using nanobubbles to kill harmful algal blooms

CFAES researchers are testing a new method to kill harmful algal blooms—using ozone nanobubbles.

The results from recent trials at Lake Sylvan in South Vienna, Ohio, and at Grand Lake St. Marys in St. Marys, Ohio—both of which have a history of severe algal blooms—are promising.

The technology being tested creates ozone and injects it into a waterway in the form of microscopic bubbles. Once in the water, the ozone can kill unwanted algae, destroy toxins, and boost oxygen levels, said Heather Raymond, director of CFAES’ Water Quality Initiative.

“The 2021 trial at Lake Sylvan was considered a success by local lake managers since recreational advisories were not needed, as compared to years prior,” Raymond said. “Testing in August 2022 at Grand Lake St. Marys West Beach, which had a more severe bloom than Lake Sylvan, resulted in park managers also not having to issue recreational advisories, while neighboring, untreated beaches required advisories.”

The Ohio Department of Natural Resources was pleased with these results and invited Ohio State to return for follow-up trials at West Beach this summer. Additional testing at the new mesocosm facility at The Ohio State University Stone Laboratory showed that ozone nanobubble treatment has less impact to beneficial zooplankton than traditional algaecides.

The trials are being conducted in partnership with scientists from the University of Florida, the U.S. Environmental Protection Agency, and the National Oceanic and Atmospheric Administration as part of a $1.6 million dollar grant from the U.S. Army Corps of Engineers. The initial one year of funding was extended to three years, based on these initial, successful trials.

The 2023 lake trials and additional experiments will help researchers understand how much ozone is needed, if the nanobubble technology also helps prevent blooms, and if there are any potential negative effects to other forms of life and the environment.