Sodium hypochlorite disinfection of SARS-CoV-2 spiked in water and municipal wastewater

Infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has the potential to be collected in wastewater from mucus, sputum, and feces of infected individuals, raising questions about the appropriate handling and treatment of the resulting wastewater. Current evidence indicates the likelihood of waterborne SARS-CoV-2 transmission is low; nonetheless, confirming the efficacy of disinfection against SARS-CoV-2 is prudent to ensure multiple barriers of protection for infectious SARS-CoV-2 that could be present in municipal and hospital wastewater. Sodium hypochlorite (free chlorine) is widely used for pathogen control in water disinfection applications. In the current study, we investigated the inactivation of SARS-CoV-2 in DI water and municipal wastewater primary influent by sodium hypochlorite (free chlorine) addition. Our results showed rapid disinfection of SARS-CoV-2, with less than 1 mg-min/L required for >3 log(10) TCID50 reduction in DI water. More than 5 mg-min/L was required for 3 log(10) TCID50 reduction in primary influent, suggesting potential shielding of the virus by suspended solids. These results are consistent with expected virus inactivation by free chlorine and suggest the adequacy of free chlorine disinfection for inactivation of infectious SARS-CoV-2 in water matrices. (C) 2021 Published by Elsevier B.V.

Automated summary

This study investigated the inactivation of SARS-CoV-2 by sodium hypochlorite (free chlorine) in DI water and municipal wastewater. The results showed rapid disinfection of SARS-CoV-2, with less free chlorine required in DI water compared to municipal wastewater. These findings suggest the adequacy of free chlorine disinfection for eliminating infectious SARS-CoV-2 in water matrices.