Dose estimation methodology for the UV inactivation of bioaerosols in a Continuous-Flow reactor

Abstract

Indoor air microbial pollution may be responsible for various human allergies and diseases. To reduce exposure, airborne bacteria can be directly controlled through devices that employ ultraviolet-C (UV-C) radiation. In this study, a continuous annular photo-reactor was used to evaluate the inactivation dose for two species: Gram-negative Escherichia coli and Pseudomonas aeruginosa. In order to provide meaningful results, a comprehensive kinetic modeling was performed, which included the evaluation of optical properties of the microorganisms and the calculation of radiation field inside the reactor. In this way, intrinsic inactivation rates could be obtained. From the reactor modeling and the experimental data sets, the first order inactivation rate or UV susceptibility for E. coli was 0.1055 m 2 J À1 , while for P. aeruginosa the obtained value was 0.2579 m 2 J À1 . The approach used allows a straightforward scaling-up of the process for real applications and microorganism species involved.

Axisymmetric radiation intensity model for annular reactors

“…An important feature in annular reactors is the axisymmetry of a cylindrical lamp and the reactor in geometry, as shown in Figure 1. It has been widely assumed that the emitters inside the lamp are uniform and homogeneous 16–21 . Thus, the lamp emission must be axisymmetric.…”

“…For the volumetric source model, the lamp is modeled as a cylindrical body and the emitters distribute uniformly inside the cylindrical body. By fixing the coordinate origin at the observed point, the extense volumetric source emission (EVSE) model was developed 16–21 . The EVSE model has been proved to precisely simulate the radiation field 22–24 .…”