Editorial perspective: Viruses in wastewater: wading into the knowns and unknowns

The COVID-19 pandemic has posed immense challenges to the fields of public health, economy and education worldwide. Yet, its transmission and attenuation in the environment are not fully elucidated. What we do know is that the water and wastewater treatment plants (WTPs/WWTPs) are most susceptible to viral contamination specifically during the current COVID-19 outbreak. Although knowledge about SARS-CoV-2 in sewage and WWTPs is limited (Foladori et al., 2020), SARS-CoV-2 is likely to be rapidly inactivated under increased temperature and by disinfectants such as bleach, ethanol, benzylalkonium chloride, povidone-iodine and chloroxylenol (Chin et al., 2020). The application of secondary disinfection measures, like dosing of chloramines to maintain a certain residual chlorine level in the distribution network adds to further protection from contamination (Bhowmick et al., 2020). However, as municipal network receives huge amount of wastewater from asymptomatic patients and treated sewage from hospitals, SARS-CoV-2 from improperly disinfected wastewater might persist for a prolonged time in pipelines, in turn becoming a secondary source of transmission (Zhang et al., 2020). Therefore, we must make sure the wastewater coming out of the SARS-CoV-2 infected areas should be properly disinfected in order to reduce the impact on the receiving water bodies. This brings in the need for careful consideration of disinfection and removal strategies for SARS-CoV-2 from contaminated waters (Kitajima et al., 2020).