Systematic investigation and modeling prediction of virus inactivation by ozone in wastewater: Decoupling the matrix effects

Abstract

Water disinfection is undoubtedly regarded as a critical step in ensuring the water safety for human consumption, and ozone is widely used as a highly effective disinfectant for the control of pathogenic microorganisms in water. Although the diminished ozone efficiencies in complex water matrices have been widely reported, the specific extent to which individual components of matrix act on the virus inactivation by ozone remains unclear, and effective methodologies to predict the comprehensive effects of various factors are needed. In this study, the decoupled impact of the intricate water matrix on the ozone inactivation of viruses was systematically investigated and assessed from a simulative perspective. The concept of "equivalent ozone depletion rate constant" (k') was introduced to quantify the influence of different species, and a kinetic model was developed based on the k' values for simulating the ozone inactivation processes in complex matrix. The mechanisms through which diverse species influenced the ozone inactivation effectiveness were identified: 1) competition effects (k' = 105∼107 M–1s−1), including organic matters and reductive ions (SO32−, NO2−, and I−), which were the most influential species inhibiting the virus inactivation; 2) shielding effects (k' = 103∼104 M–1s−1), including Ca2+, Mg2+, and kaolin; 3) insignificant effects (k' = 0∼1 M–1s−1), including Cl−, SO42−, NO3−, NH4+, and Br−; 4) promotion effects (k' = ∼−103 M–1s−1), including CO32− and HCO3−. Prediction of ozone disinfection efficiency and evaluation of species contribution under complex aquatic matrices were successfully realized utilizing the model. The systematic understanding and methodologies developed in this research provide a reliable framework for predicting ozone inactivation efficiency under complex matrix, and a potential tool for accurate disinfectant dosage determination and interfering factors control in actual wastewater treatment processes.