Radiation Modeling and the Simulation of the Microorganism Disinfection in Ultraviolet Reactors

Abstract

Ultraviolet disinfection can effectively destroy waterborne microorganisms. Modeling ultraviolet disinfection includes the solution of the flow field, the radiation field, and the concentration field. Radiation plays an important role in the inactivation kinetics of microorganisms. The present study presents the irradiance method to determine the irradiation flux at the lamp surface, which satisfies the energy conservation law. A careful analysis shows that the fluence rate method may overestimate the emitted energy of the lamp nearly 30–40% and violates the energy conservation law. The simulation of ultraviolet reactors shows that the fluence rate is overestimated by the fluence rate method. The concentration of microorganisms in ultraviolet reactors is also overestimated nearly 32% by the fluence rate method than by the irradiance method. The LOG reduction predicted using the fluence rate method is nearly 50% more than that using the irradiance method. The present irradiance method can ensure energy conservation and predict the correct disinfection performance in ultraviolet reactors.