It is imperative that aquaculturists can continue to provide consumers with safe seafood as the industry grows and adapts to a changing climate. Oyster aquaculture is particularly vulnerable to the intersection of seafood safety and climate change. Harvested oysters are at risk for carrying enteric bacteria and viruses that can make consumers ill, notably from Vibrio spp. bacteria. The prevalence of Vibrio spp. is expected to rise with increasing water temperatures. While post-harvest processing approaches currently employed to reduce risk of contaminated oysters are effective in reducing pathogens, they have specific drawbacks for growers, including requiring high levels of capital to gain access to treatment equipment, poor consumer reception of treated products, and death of treated oysters.
As part of my thesis research, I aim to demonstrate efficacy of two new technologies, individually and combined, in removing pathogens from oyster tissues and aquaculture system water leading to a post-harvest treatment that is more effective than traditional depuration, has low oyster mortality and is cost-effective for growers. This will be accomplished through a series of controlled experiments utilizing both technologies. The first technology is a modified photocatalytic oxid ation process which produces ozone and other free radicals, which are incorporated into the experimental system water through the air supply. Output from this technology is being quantified using the indigo method to measure dissolved ozone . The second technology creates nanobubbles using magneto-chemistry and is plumbed in- line with the filtration of treatment tanks. The free energy that is generated by this technology will be measured in millivolts using a multimeter.
The first step and focus of this presentation is the calibration of the two disinfection technologies and determination of their respective disinfection potentials in our experimental systems. These measurements will allow for the determination of a base level output for each technology. Once the base output is determined, conditions within the experimental systems will be manipulated (water flow, temperature, salinity, and volume) so that disinfection potential under a variety of conditions can be determined. It is expected that temperature, water flow and system volume will have an effect on the output of the technologies.