Elimination of pathogenic Aeromonas and Flavobacterium strains in the aquatic environment using CaviPlasma

Abstract

Background: The key limiting factor for recirculating aquaculture systems (RAS) is maintaining good water quality, which requires keeping the system free of bacterial pathogens. In this study, we investigated the potential of CaviPlasma water treatment technology for the industrial-scale disinfection of RAS water. Methods: We focused on the remediation of model suspensions containing Aeromonas salmonicida, Aeromonas hydrophila, and Flavobacterium psychrophilum, which are important fish disease causative agents that represent significant health risks for reared fish. The CaviPlasma technology utilized is based on advanced oxidation processes induced by plasma discharge in fast-flowing liquids, synergized with the hydromechanical effects of cavitation. Results: Our results demonstrated strong biocidal efficiency of CaviPlasma water treatment without chemical or medical additives. F. psychrophilum was completely eliminated immediately after treatment, even at the lowest plasma dose (8.4 kJ/L). Aeromonads displayed slightly higher resistance; instant elimination of aeromonads was achieved with a plasma dose of 25.2 kJ/L, or 33.6 kJ/L. However, during post-treatment incubation, the concentration of live aeromonads gradually decreased to zero, even at the lowest plasma dose. Conclusions: Our pilot study revealed that CaviPlasma technology is a promising sanitization method with potential for use in recirculation aquaculture systems (RAS). It offers approximately m3/h treatment performance and the potential to greatly limit the environmental burden and long-term side effects, such as acquired bacterial resistance due to persistent chemical residues associated with common sanitization technologies that utilize antibiotics or chemical treatment of RAS.