Inactivation differences of microorganisms by low pressure UV and pulsed xenon lamps

TLDR

UV disinfection, traditionally performed with low‑pressure or medium‑pressure lamps, is limited by poor light penetration in turbid water and potential photoreactivation, prompting interest in high‑energy, wide‑wavelength pulsed‑xenon lamps. The study aimed to compare the inactivation efficiencies of low‑pressure UV and pulsed‑xenon lamps on two coliphage types and three Escherichia coli strains. Researchers exposed the microorganisms to both lamp types, measuring survival and photoreactivation rates across the different strains and phages. Pulsed‑xenon lamps reduced photoreactivation of E.

Abstract

UV disinfection has been applied to water treatment in recent years with low-pressure and medium-pressure UV lamps mainly used as the light source. In general, UV disinfection is considered to be inefficient with water of high turbidity because of inhibition of light penetration. Additionally, photoreactivation may be a problem that should be considered in case a disinfected water is discharged to the environment where sunlight causes reactivation. Recently, other types of lamps have been proposed including a flush-type lamp (such as a pulsed-xenon lamp) that emits high energy and wide wavelength intermittently. In this study, the difference between inactivation efficiencies by low-pressure UV (LPUV) and pulsed-xenon (PXe) lamps was investigated using two coliphage types and three strains of Escherichia coli. PXe had a suppressive effect on photoreactivation rate of the E. coli strains even though there was no significant effect on inactivation rate and maximum survival ratio after photoreactivation. PXe also had a benefit when applied to high turbidity waters as no tailing phenomena were observed in the low survival ratio area although it was observed in LPUV inactivation. This efficiency difference was considered to be due to the difference in irradiated wavelength of both lamps.