Kinetics of Inactivation of Waterborne Enteric Viruses by Ozone

Abstract

Ozone is an effective disinfectant against all types of waterborne pathogens. However, accurate and quantitative kinetic data regarding virus inactivation by ozone are scarce, because of the experimental challenges associated with the high reactivity of ozone toward viruses. Here, we established an experimental batch system that allows tailoring and quantifying of very low ozone exposures and simultaneously measuring virus inactivation. Second-order ozone inactivation rate constants (k) of five enteric viruses [laboratory and two environmental strains of coxsackievirus B5 (CVF, CVEnv1, and CVEnv2), human adenovirus (HAdV), and echovirus 11 (EV)] and four bacteriophages (MS2, Qβ, T4, and Φ174) were measured in buffered solutions. The k values of all tested viruses ranged from 4.5 × 10 to 3.3 × 10 M s. For MS2, k depended only weakly on temperature (2-22 °C; E = 22.2 kJ mol) and pH (6.5-8.5), with an increase in k with increasing pH. The susceptibility of the selected viruses toward ozone decreases in the following order: Qβ > CVEnv2 > EV ≈ MS2 > Φ174 ≈ T4 > HAdV > CVF ≈ CVEnv1. On the basis of the measured k and typical ozone exposures applied in water and wastewater treatment, we conclude that ozone is a highly effective disinfectant for virus control.

Differences in Viral Disinfection Mechanisms as Revealed by Quantitative Transfection of Echovirus 11 Genomes

“…Ozone inactivation of E11 was performed as described previously (38). Briefly, an ozone stock solution was prepared by continuously bubbling an ozone-containing oxygen gas through Milli-Q water kept at ϳ4°C; ozone concentrations were measured by UV-Vis absorption at 260 nm with a molar absorption coefficient of 3,200 M Ϫ1 cm Ϫ1 (39).…”

“…Briefly, an ozone stock solution was prepared by continuously bubbling an ozone-containing oxygen gas through Milli-Q water kept at ϳ4°C; ozone concentrations were measured by UV-Vis absorption at 260 nm with a molar absorption coefficient of 3,200 M Ϫ1 cm Ϫ1 (39). An ozone stock was applied to an experimental solution of PBS (pH 6.5) containing ϳ0.25 mM trans-cinnamic acid (Sigma-Aldrich) to control the ozone exposure (38), ϳ0.02 M tert-butanol (Sigma-Aldrich) to scavenge hydroxyl radicals, and an E11 concentration of ϳ1 ϫ 10 5 to 1 ϫ 10 6 IV/ml (38). Ozone doses ranged from 2.7 to 9.8 mg O 3 /liter (corresponding to 5.6 ϫ 10 Ϫ5 to 2.05 ϫ 10 Ϫ4 M), yielding estimated ozone exposures ranging from (0.02 to 0.27) mg · s/liter (38).…”

“…An ozone stock was applied to an experimental solution of PBS (pH 6.5) containing ϳ0.25 mM trans-cinnamic acid (Sigma-Aldrich) to control the ozone exposure (38), ϳ0.02 M tert-butanol (Sigma-Aldrich) to scavenge hydroxyl radicals, and an E11 concentration of ϳ1 ϫ 10 5 to 1 ϫ 10 6 IV/ml (38). Ozone doses ranged from 2.7 to 9.8 mg O 3 /liter (corresponding to 5.6 ϫ 10 Ϫ5 to 2.05 ϫ 10 Ϫ4 M), yielding estimated ozone exposures ranging from (0.02 to 0.27) mg · s/liter (38). After ozone addition, the experimental solutions were stirred and allowed to react for 3 min until complete ozone depletion.…”

Ozone and Photocatalytic Processes for Pathogens Removal from Water: A Review

“…Domestic wastewater will always contain microorganisms, either from human or animal origin, some of them pathogenic to humans. Therefore, the treatment of such wastewaters should assure that such pathogens are eliminated, effective for viruses removal [3,21,22], either by promoting protein coagulation or oxidation of nuclei acids [23]. Besides, its capacity of polishing the wastewater by removing some of the chemical oxygen demand makes it an interesting water disinfection process [24].…”

Virus inactivation in groundwater in a postglacial lava field in arctic climate

“…PhiX174 is one of the more environmentally stable viruses and has been found to be highly temperature resistant in comparison with pathogenic viruses, while MS2 is known to be more sensitive to temperature, but to be quite stable at temperatures below 10°C (DeBorde et al ; Bae and Schwab ; Charles et al ; Bertrand et al ). Both PhiX174 and MS2 have been used as surrogates of enteric viruses in many recent studies regarding inactivation and disinfection treatments, like ozone inactivation (Wolf et al ), solar disinfection (Kohn et al ), disinfection with UVC‐LED treatment (Kim et al ), iron electrocoagulation treatment (Heffron et al ) and filtration (Frohnert et al ). Information of persistence of the two phages in the type of groundwater studied here would as such be beneficial for comparison in future studies of virus transfer and removal in this kind of environment.…”