DEVELOPMENT AND VALIDATION OF A GENERAL-MODEL FOR PREDICTING BIOLOGICAL EFFICACY OF UV REACTORS AGAINST PLANT-PATHOGENS IN IRRIGATION WATER

A numerical simulation tool Was developed to predict disinfection effi cacy of an ultraviolet (UV) reactor against a plant pathogen. The simu lation tool coupled the UV dose response of Fusarium oxysporum, UV tra nsmission characteristics and water quality, and particle trajectories during transport through the UV reactor. UV dose and mortalities of m icroorganisms flowing through the UV reactor were predicted numericall y. Flow-through bioassay experiments were conducted on the UV reactor for different flow; rates and UV transmissions, Numerical predictions and results from the bioassay tests were compared. Numerical simulatio n predictions were within 95% confidence limits of bioassay results at all flow rates and UV transmissions (at 254 nm) above 49% (at 1 cm). There were minimal differences between numerical predictions and bioas say tests for UV transmissions between 14-49%. At low flow rates and b elow UV transmissions of 14%, the numerical results underpredicted the observed bioassay results. The procedures developed from this researc h mag, be used to design UV treatment techniques of other liquid proce sses and to reduce significantly the need for prototype construction a nd testing.