Enteric viruses in municipal wastewater effluent before and after disinfection with chlorine and ultraviolet light

Abstract

In Ontario, Canada, information is lacking on chlorine and ultraviolet (UV) light disinfection performance against enteric viruses in wastewater. We enumerated enteroviruses and noroviruses, coliphages, and Escherichia coli per USEPA methods 1615, 1602, and membrane filtration, respectively, in pre- and post-disinfection effluent at five wastewater treatment plants (WWTPs), with full-year monthly sampling, and calculated log10 reductions (LRs) while WWTPs complied with their monthly geometric mean limit of 200 E. coli/100 mL. Modeling of densities by left-censored estimation and Bayesian inference gave very similar results. Polymerase chain reaction (PCR)-detected enteroviruses and noroviruses were abundant in post-disinfection effluent (mean concentrations of 2.1 × 10+4–7.2 × 10+5 and 2.7 × 10+4–3.6 × 10+5 gene copies (GC)/L, respectively). Chlorine or UV disinfection produced modest LRs for culture- (0.3–0.9) and PCR-detected enteroviruses (0.3–1.3), as well as noroviruses GI + GII (0.5–0.8). Coliphages and E. coli were more susceptible, with LRs of 0.8–3.0 and 2.5, respectively. Sand-filtered effluent produced significantly higher enteric virus LRs (except cultured enteroviruses). Coliphage and human enteric virus densities gave significantly positive correlations using Kendall's Tau test. Enteric viruses are abundant in wastewater effluent following routine chlorine or UV disinfection processes that target E. coli. Coliphages appear to be good indicators for evaluating wastewater disinfection of enteric viruses.

Interactions between Human Reovirus and Free-Living Amoebae: Implications for Enteric Virus Disinfection and Aquatic Persistence

“…27 Additional studies will be required to understand how/why the virus enters the nucleus, as well as to understand the mechanisms for virion uptake by trophozoites in general, all which may lead to an increased likelihood/pressure on the FLA to encyst. 28 A wide range of disinfection treatments have been studied to control and prevent enteric virus infections; 3,29,30 however, very limited studies have examined protection within protozoa 31,32 with none having looked at reovirus. Finally, reovirus infectivity during UV irradiation of freely suspended virions was compared to internalized virions.…”

Side-Stream Comparison of Peracetic Acid and Chlorine as Hypochlorite for Disinfection of Municipal Wastewater Effluent at a Full-Scale Treatment Facility, Ontario, Canada

“…Enteroviruses were assayed by both culture on buffalo green monkey (BGM) kidney cells and RT-qPCR, while noroviruses group I and group II by RT-qPCR; F + male-specific and somatic coliphages were enumerated according to USEPA Method 1602 . The sampling (including matrix spiking) and testing methodologies are reported by us elsewhere E.…”

Coronavirus 2 (SARS-CoV-2) in water environments: Current status, challenges and research opportunities

“…The traditional treatment techniques for the removal of viruses from wastewater include sand filters, chlorine treatment, UV inactivation, ozone treatment, microbial treatment, membranes and pond systems [ [85] , [86] , [87] , [88] , [89] , [90] ]. Though it is assumed that the current techniques used for wastewater treatment might be helpful to eliminate the novel virus; due to the global impact of this pandemic, experimental results are needed to validate this assumption [ 62 , [91] , [92] , [93] ].…”