Inactivation of Adenoviruses, Enteroviruses, and Murine Norovirus in Water by Free Chlorine and Monochloramine

Atlanta Research and Education Foundation, Atlanta, Georgia 30341, USA.
Applied and Environmental Microbiology (Impact Factor: 3.67). 12/2009; 76(4):1028-33. DOI: 10.1128/AEM.01342-09
Source: PubMed


Inactivation of infectious viruses during drinking water treatment is usually achieved with free chlorine. Many drinking water utilities in the United States now use monochloramine as a secondary disinfectant to minimize disinfectant by-product formation and biofilm growth. The inactivation of human adenoviruses 2, 40, and 41 (HAdV2, HAdV40, and HAdV41), coxsackieviruses B3 and B5 (CVB3 and CVB5), echoviruses 1 and 11 (E1 and E11), and murine norovirus (MNV) are compared in this study. Experiments were performed with 0.2 mg of free chlorine or 1 mg of monochloramine/liter at pH 7 and 8 in buffered reagent-grade water at 5 degrees C. CT values (disinfectant concentration x time) for 2- to 4-log(10) (99 to 99.99%) reductions in virus titers were calculated by using the efficiency factor Hom model. The enteroviruses required the longest times for chlorine inactivation and MNV the least time. CVB5 required the longest exposure time, with CT values of 7.4 and 10 mg x min/liter (pH 7 and 8) for 4-log(10) inactivation. Monochloramine disinfection was most effective for E1 (CT values ranged from 8 to 18 mg x min/liter for 2- and 3-log(10) reductions, respectively). E11 and HAdV2 were the least susceptible to monochloramine disinfection (CT values of 1,300 and 1,600 mg-min/liter for 3-log(10) reductions, respectively). Monochloramine inactivation was most successful for the adenoviruses, CVB5, and E1 at pH 7. A greater variation in inactivation rates between viruses was observed during monochloramine disinfection than during chlorine disinfection. These data will be useful in drinking water risk assessment studies and disinfection system planning.

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    • "The difference may be due to the different experimental conditions such as pH and temperature, because we worked at pH 7.2 at 20°C while Baxter's study was done at pH 8.5 at 5°C. However, it was similar with a study by Cromeans et al. (2010) conducted at similar pH but targeting different serotypes (AdV2). As for MS2, a 0.77 mg-min/L of CT value was required for 2 log inactivation, which was comparable with a study by Clevenger et al. (2007) at similar experimental condition (pH 7, 22°C). "
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    ABSTRACT: Adenoviruses, the most UV resistant microorganism currently known, are posing concerns in UV treated drinking water. To reduce the risk from adenovirus infection, combination processes of UV and chlorination are attractive. Bacteriophage MS2 and adenovirus 5 (AdV5) were used in this study, and inactivated by low-pressure UV (LPUV) lamp, chlorination, sequential processes (UV-Cl 2 and Cl 2 -UV) and a simultaneous process (UV/Cl 2). MS2 was more resistant against chlorine than AdV5, and CT values for 2 log reduction of MS2 and AdV5 were 0.77 and 0.033 mg-min/L, respectively. However, AdV5 was more resistant to UV than MS2 and required a 101 mJ/cm 2 of fluence for 2 log reduction. Compared to the application of UV or chlorine separately, an increasing trend of MS2 inactivation rate was found in the sequential processes, which was statistically significant (p < 0.05, ANCOVA). The simultaneous process of UV/Cl 2 for MS2 provided about 2.3 times higher inactivation rate than a summation of inactivation rates by the separate application of either chlorine or UV, even at the same UV fluence rate and the same initial chlorine concentration. The combination processes of UV and chlorine, either sequential or simultaneous application, seemed to be more effective than a standalone process in viral inactivation.
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    • "As a result, assessment of norovirus inactivation is typically evaluated using research surrogates, such as murine norovirus (MNV; Kingsley et al., 2007), feline calicivirus (FCV; Tree et al., 2005; Duizer et al., 2004a), and Tulane virus (Li et al., 2013). This is particularly true for the disinfectant research which principally utilizes FCV and MNV to assess probable inactivation by various sanitizers (Cromeans et al., 2010; D'Souza and Su, 2010; Fraisse et al., 2011; Kahler et al., 2010; Lim et al., 2010; Nowak et al., 2011; Predmore and Li, 2011; Tree et al., 2005; Urakami et al., 2007). While studies utilizing geneticallyrelated viruses are of clear value, use of these research surrogates has some caveats. "
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    • "Different strategies have been developed to eliminate HAdV, mostly based on inactivation of virus by UV technologies (e.g. Baxter et al., 2007; Meng and Gerba, 1996; Thurston-Enriquez et al., 2003b), ozone (Thurston-Enriquez et al., 2005), or chemical disinfectants such as free chlorine (Baxter et al., 2007; Cromeans et al., 2010; Thurston-Enriquez et al., 2003a), monochloramine (Baxter et al., 2007; Cromeans et al., 2010; Sirikanchana et al., 2008) or by combination of these technologies (Lee and Shin, 2011; Shin and Lee, 2010). High hydrostatic pressure (HHP) processing is a non-thermal, energy-efficient and emergent inactivation technology, which has "
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