Interfacial mechanism and inactivation efficiency of bacteriophage MS2 by ozone in high turbidity and algal-laden water resource

With the onset of the COVID-19 epidemic and the measures implemented to curb the spread of the SARS-CoV-2 virus, there has been increasing attention on safe drinking water and waterborne viruses during water treatment processes. In this study, we investigate the impact of solution chemistry, including ionic strength (Na+ or Ca2+) pH, and natural organic matter (NOM), on the efficiency of MS2 bacteriophage inactivation by ozone in the presence of inorganic and organic particles (kaolinite (KAO) and microcystis aeruginosa (MA), respectively). The study results demonstrate that KAO has been found to adsorb MS2, but it does not significantly affect the inactivation of MS2 by ozone. In contrast, the inactivation of MS2 increased at low MA concentrations ranging from 105 to 106 cells/L due to MS2 dispersion, but decreased at higher concentrations ranging from 107 to 108 cells/L. The monovalent Na+ ion solutions (~200 mmol/L) maintain MS2 stability and dispersion irrespective of the presence of particles, and did not affect inactivation. Additionally, MS2 aggregates in divalent Ca2+ solutions, resulting in reduced inactivation with or without particles present. Increasing the solution's pH had a negative impact on inactivation, leading to ozone reduction and weakening of the inactivation. However, the presence of NOM poses a significant risk to the safety of drinking water by reducing MS2 inactivation.