Kinetics and Mechanisms of Virus Inactivation by Chlorine Dioxide in Water Treatment: A Review

Abstract

Chlorine dioxide (ClO₂), an alternative disinfectant to chlorine, has been widely applied in water and wastewater disinfection. This paper aims at presenting an overview of the inactivation kinetics and mechanisms of ClO₂ with viruses. The inactivation efficiencies vary greatly among different virus species. The inactivation rates for different serotypes within a family of viruses can differ by over 284%. Generally, to achieve a 4-log removal, the exposure doses, also being referred to as Ct values (mutiplying the concentration of ClO₂ and contact time) vary in the range of 0.06-10 mg L^-1 min. Inactivation kinetics of viruses show two phases: an initial rapid inactivation phase followed by a tailing phase. Inactivation rates of viruses increase as pH or temperature increases, but show different trends with increasing concentrations of dissolved organic matter (DOM). Both damages in viral proteins and in the 5' noncoding region within the genome contribute to virus inactivation upon ClO₂ disinfection.

Keywords: Chlorine dioxide (ClO2); Disinfection; Kinetics; Mechanisms; Virus; Water treatment.

Fig. 1

The log removal of viruses during ClO₂ disinfection. Note: the data of enveloped virus is circled; the line indicates the variations of Ct values to achieve the 4-log removal. The legend with a black edge indicates that Ct value is the product of initial concentration of ClO₂ and contact time

Fig. 2

Inactivation mechanisms of viruses by ClO₂