Coronaviruses in wastewater processes: Source, fate and potential risks

Abstract

The last 17 years have seen three major outbreaks caused by coronaviruses, with the latest outbreak, COVID-19, declared a pandemic by the World Health Organization. The frequency of these outbreaks, their mortality and associated disruption to normal life calls for concerted efforts to understand their occurrence and fate in different environments. There is an increased interest in the occurrence of coronaviruses in wastewater from the perspective of wastewater-based epidemiology. However, there is no comprehensive review of the knowledge on coronavirus occurrence, fate and potential transmission in wastewater.This paper, provides a review of the literature on the occurrence of coronaviruses in wastewater treatment processes. We discuss the presence of viral RNA in feces as a result of diarrhoea caused by gastrointestinal infections. We also reviewed the literature on the presence, survival and potential removal of coronaviruses in common wastewater treatment processes. The detection of infectious viral particles in feces of patients raises questions on the potential risks of infection for people exposed to untreated sewage/wastewater. We, therefore, highlighted the potential risk of infection with coronaviruses for workers in wastewater treatment plants and the public that may be exposed through faulty plumbing or burst sewer networks.The mortalities and morbidities associated with the current COVID-19 pandemic warrants a much more focused research on the role of environments, such as wastewater and surface water, in disease transmission. The current wealth of knowledge on coronaviruses in wastewater based on the reviewed literature is scant and therefore calls for further studies.

Tracking SARS-CoV-2 RNA through the wastewater treatment process

“…by liquid aerosols, has not as yet been ruled out. 6,29 To increase the sensitivity of the analysis, we concentrated the water samples using ultrafiltration with sterile dialysis membranes, thus lowering the effective detection limit (2000 copies·mL -1 for non-concentrated samples) by a factor of 17-96. This pre-concentration technique, however, was not applied to the raw sewage due to the high concentration of bio-solids.…”

“…The new human coronavirus (SARS-CoV-2), was found in urine and feces 1–9 of infected individuals, as well as in various wastewater systems. 6,10–14 Consequently, there has been a recent global interest in monitoring the dissemination of SARS-CoV-2 in municipal sewages, mainly for wastewater-based epidemiology (WBE). 3,15–20 The implication that wastewater is a potential dissemination and infection route, has been also discussed, 13,21–23 however, empirical evidences are still scarce.…”

Uncertainties in estimating SARS-CoV-2 prevalence by wastewater-based epidemiology

“…This potentially causes health and safety concerns regarding the effluent discharge and work environment for site workers in WWTPs. The removal of viruses at WWTPs can be due to the adsorption to suspended solids, protein and nucleic acid denaturation, retention or size exclusion (if membrane process is involved), disinfection that can damage the capsid protein or nucleic acids [88] . As WBE primarily focuses on raw wastewater collected from WWTPs or sewers, the persistence of SARS-CoV-2 in response to different treatment strategies is thus not expanded herein.…”

Wastewater surveillance for SARS-CoV-2 on college campuses: Initial efforts, lessons learned and research needs

“…Safety protocols: Researchers are still unsure how persistent infective SARS-CoV-2 is in wastewater (Amoah, Kumari, and Bux 2020), leading to uncertainty about the necessary levels of laboratory disinfection, equipment cleaning, and protective equipment required by personnel to collect and analyze samples. Biosafety protocols posed a hurdle for many college laboratories.…”