Pathogen Reduction in Closed Aquaculture Systems by UV Radiation: Fact or Artifact?

Abstract

Differential equations were used to set a theoretical upper limit for the efficacy of UV radiation in 3 hypothetical aquaculture systems: (a) a plug-flow system, (b) a n idealized closed system with no influx of pathogens, and (c) a conventional closed system in which the influx of pathogens is continuous. The equations demonstrate that, in a conventional closed system, the mass of pathogens never reaches zero even if the UV sterilizer is 100 % effective. This suggests that agents such a s UV radiation, which do not form persistent residuals, may b e incapable of preventing the spread of water-borne pathogens in systems that are recirculated. Use of UV radiation in aquaculture is most effective in sterilization of raw water supplies and discharges lnto receiving waters, both of which are single-pass applications.