Evaluation of Nanobubble Ozone Technology (NBOT) for Cyanobacterial Harmful Algal Bloom Control

Effective Cyanobacterial Harmful Algal Bloom (cyanoHAB) control strategies are needed to address recreational and drinking water impacts. Nanobubble ozone technology (NBOT) is an emerging control method, but cyanoHAB efficacy studies are limited. Lab and mesocosm NBOT experiments, and full-scale field NBOT treatment trials were conducted June 2021 through October 2023. Lab studies evaluated nanobubble size distribution, density, lifetime, aqueous ozone and hydroxyl radical production, and impact of organic matter on dose response. Lab studies confirmed production of high densities of nanobubbles and the total hydroxyl radical production from nanobubble collapse alone (no ozone) was insufficient for the oxidation demand for most treatments. These results indicate that nanobubble technology without ozone gas, claiming to work through the action of hydroxyl radical production, is not a suitable treatment. Mesocosm studies compared efficacy of NBOT to traditional algaecide treatments and evaluated impacts to non-target organisms. Algaecides decreased the zooplankton community while the lower dose NBOT treatment increased the abundance of zooplankton and the higher dose NBOT treatment had only minor negative impacts. In mesocosms, NBOT treatment reduced cyanoHABs at all doses. Multi-month NBOT trials were conducted at Lake Sylvan and Grand Lake Saint Mary’s West Beach. At Lake Sylvan, following increased NBOT dose, cyanobacteria concentrations decreased, the community shifted, and recreational advisories were avoided. Cyanobacteria and toxin concentrations were higher during the Grand Lake Saint Mary’s beach NBOT trial and treatment effects were localized and minimal, which could be due to scale, bloom intensity and/oe application rate.

Primary Presenter: Dail Laughinghouse, University of Florida (hlaughinghouse@ufl.edu)

Authors:

Heather Raymond, The Ohio State University  (Raymond.54@osu.edu)

Haley Kuhn, The Ohio State University  (kuhn.701@buckeyemail.osu.edu)

Autumn Taylor, University of Florida  (autumntaylor@ufl.edu)

Holly Stanley, The Ohio State University  (stanley.406@buckeyemail.osu.edu)

Lillian Labus, The Ohio State University  (labus.8@buckeyemail.osu.edu)

David Berthold, University of Florida  (dberthold@ufl.edu)

Forrest Lefler, University of Florida  (flefler@ufl.edu)

Justin Chaffin, The Ohio State University  (chaffin.46@osu.edu)

Rachel Gabor, The Ohio State University  (gabor.40@osu.edu)

Linda Weavers, The Ohio State University  (weavers.1@osu.edu)

Dail Laughinghouse, University of Florida  (hlaughinghouse@ufl.edu)

Eugene Braig, The Ohio State University  (braig.1@osu.edu)