Unveiling the potential of far-UVC: Assessing irradiance and dose-response for microbial inactivation in UV systems

The efficacy of Far-UVC irradiation in inactivating microbes within a cylindrical chamber is investigated in this study. Utilizing a Far-UVC excimer lamp, the research delves into the impact of various parameters on microbial inactivation. These parameters include diffuse irradiance (UV lamp efficiency), UV transmittance (UVT), and Reynolds number. An user-defined function calculates UV dosages received by microbes traversing the system. Results are quantified in terms of the distribution of UV irradiance within the chamber and reduction equivalent dose (RED). Dose-response and Frequency-dose curves are generated for diverse scenarios. The target microorganism, MS2 bacteriophage, underscores the investigation, with particular attention paid to the effect of UVT and UV lamp efficiency on effluent log inactivation. Nine cases are investigated, considering a variety of these parameters, and the results highlighted certain trends. Some cases exhibited narrow and low-dose distributions, pointing to scenarios where UV treatment might be insufficient, while others demonstrated a correlation between higher UV doses and increased log inactivation rates, suggesting more efficient microbial elimination. Notably, cases with higher UV doses also showed a leveling-off effect, implying that after a certain threshold, the microbial population's vulnerability to UV diminishes, or that the majority of microbes susceptible to easy inactivation have already been addressed.