A modeling approach to estimate the solar disinfection of viral indicator organisms in waste stabilization ponds and surface waters
Articolo
Data di Pubblicazione:
2016
Abstract:
Sunlight is known to be a pertinent factor governing the infectivity of waterborne viruses in the environment.
Sunlight inactivates viruses via endogenous inactivation (promoted by absorption of solar light
in the UVB range by the virus) and exogenous processes (promoted by adsorption of sunlight by external
chromophores, which subsequently generate inactivating reactive species). The extent of inactivation is
still difficult to predict, as it depends on multiple parameters including virus characteristics, solution
composition, season and geographical location. In this work, we adapted a model typically used to estimate
the photodegradation of organic pollutants, APEX, to explore the fate of two commonly used
surrogates of human viruses (coliphages MS2 and fX174) in waste stabilization pond and natural surface
water. Based on experimental data obtained in previous work, we modeled virus inactivation as a
function of water depth and composition, as well as season and latitude, and we apportioned the contributions
of the different inactivation processes to total inactivation. Model results showed that fX174 is
inactivated more readily than MS2, except at latitudes >60. fX174 inactivation varies greatly with both
season (20-fold) and latitude (10-fold between 0 and 60), and is dominated by endogenous inactivation
under all solution conditions considered. In contrast, exogenous processes contribute significantly to
MS2 inactivation. Because exogenous inactivation can be promoted by longer wavelengths, which are
less affected by changes in season and latitude, MS2 exhibits smaller fluctuations in inactivation
throughout the year (10-fold) and across the globe (3-fold between 0 and 60) compared to fX174. While
a full model validation is currently not possible due to the lack of sufficient field data, our estimated
inactivation rates corresponded well to those reported in field studies. Overall, this study constitutes a
step toward estimating microbial water quality as a function of spatio-temporal information and easy-todetermine
solution parameters.
Tipologia CRIS:
03A-Articolo su Rivista
Elenco autori:
Kohn, Tamar; Mattle, Michael J.; Minella, Marco; Vione, Davide Vittorio
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