Recent Update on UV Disinfection to Fulfill the Disinfection Credit Value for Enteric Viruses in Water

Abstract

Ultraviolet (UV) radiation alone or in combination with other oxidation processes is increasingly being considered for water disinfection because of stringent regulatory requirements for pathogen inactivation. To fulfill this requirement, an appropriate UV dose or fluence (mJ/cm2) is applied to combat enteric viruses in surface or treated water. There is a need for a cumulative review on the effectiveness of current and emerging UV technologies against various types of human enteric viruses. We extracted the kinetics data from 52 selected experimental studies on enteric virus inactivation using low pressure (LP-UV), medium pressure (MP-UV), UV-LED, and advanced oxidation processes (AOPs) and applied a simple linear regression analysis to calculate the range of UV fluence (mJ/cm2) needed for 4-log10 inactivation. The inactivation of adenoviruses with LP-UV, MP-UV, and UV/H2O2 (10 mg/L) required the highest fluence, which ranged from 159 to 337, 45, and 115 mJ/cm2, respectively. By contrast, when using LP-UV, the inactivation of other enteric viruses, such as the Caliciviridae and Picornaviridae family and rotavirus, required fluence that ranged from 19 to 69, 18 to 43, and 38 mJ/cm2, respectively. ssRNA viruses exhibit higher sensitivity to UV radiation than dsRNA and DNA viruses. In general, as an upgrade to LP-UV, MP-UV is a more promising strategy for eliminating enteric viruses compared to AOP involving LP-UV with added H2O2 or TiO2. The UV-LED technology showed potential because a lower UV fluence (at 260 and/or 280 nm wavelength) was required for 4-log10 inactivation compared to that of LP-UV for most strains examined in this critical review. However, more studies evaluating the inactivation of enteric viruses by means of UV-LEDs and UV-AOP are needed to ascertain these observations.

Persistence of Infectious Human Norovirus in Estuarine Water

“…A volunteer study showed that norovirus remained infectious for at least 61 days in a spiked groundwater at room temperature in the dark (using an original dose of ~ 6.5 × 10 8 genomic equivalent copies) but was limited due to the cohort size (Seitz et al, 2011 ). Surrogate viruses such as murine norovirus, feline calicivirus and Tulane virus exhibit different sensitivities to inactivation, disinfection and/or anti-viral agents (Augsburger et al, 2021 ; Knight et al, 2016 ). Data from only molecular testing methods, including those utilising an intercalating dye such as propidium monoazide may not accurately inform on infectivity, as results depend largely on the mode of inactivation (Leifels et al, 2020 ).…”

Aligning monitoring of virus barriers in potable reuse with unit process treatment mechanisms and time scales: A critical review and research needs

“…When applied to clear, low‐particulate effluents such as RO permeates, UV and UV‐AOP processes can reliably achieve very high pathogen removal based on known relationships between UV dose and pathogen log removal (USEPA, 2006). Consistent with these dose/response relationships, reported log removals of enteric viruses range from 1 to 6 for UV systems in the 10–100 mJ/cm 2 dose range (Hijnen et al, 2006), and >6 for AOP processes at 400 mJ/cm 2 and above (Augsburger et al, 2021). Within the lower range (non‐AOP) dosing range, the variability in observed LRVs is partially attributable to the varying UV sensitivity of different viruses, with adenoviruses showing particular resistance to UV and generally having the lowest inactivation rate constants (Hijnen et al, 2006).…”

A review on disinfection methods for inactivation of waterborne viruses

“…However, the efficiency of cavitation for the disinfection of SARS-CoV-2 has not been investigated. Adenoviruses which have been reported to be resistant to UV irradiation (Augsburger et al, 2021), and monochloramination (Gall et al, 2016), are inactivated by both ozonation and photocatalysis disinfection (Chen et al, 2021a). Furthermore, Chen et al (2021b) mentioned that inactivation of E. coli, Clostridium perfringens, Vibrio cholerae, and MS2 was faster using chlorine-active substances produced on-site compared to chlorine.…”