Examinando por Autor "Samoili, Sofia"

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Predicting the bactericidal efficacy of solar disinfection (SODIS): from kinetic modeling of in vitro tests towards the in silico forecast of E. coli inactivation
(Elsevier, 2022-01-01) Samoili, Sofia; Farinelli, Giulio; Moreno-SanSegundo, José Ángel; McGuigan, Kevin G.; Marugán, Javier; Pulgarín, César; Giannakis, Stefanos
In this study, the possibility of predicting the efficacy of Solar water disinfection (SODIS) for the removal of bacterial pathogens was assessed by the development of a three-level plan: firstly, systematic E. coli inactivation was performed (in vitro) in Lake Geneva water, under otherwise controlled conditions of water temperature (20–50 °C), sunlight intensity (0–1200 W/m2), presence of natural dissolved organic matter (DOM, 0–6 mg/L) and turbidity (0–50 NTU). As a second step a kinetic evaluation led to the selection of the most relevant parameters to be included in a novel static and dynamic model theoretical formulation. The static and dynamic models reliably described the experimental findings (bacterial inactivation under various climatic conditions) and were considered as equally eligible candidates for disinfection modeling. The final step considered ambient temperature, incident radiation and cloud-cover data to forecast (in silico) SODIS efficacy in Africa as a case study. The simulation results were compared with the experimental data and indicated that most African regions are suitable for SODIS processes, but there are areas of risk correlated with climatological conditions (cloud-cover and temperature). The results of this study could be applied for regional in decision-making strategies for application of SODIS or in the search for viable alternatives to SODIS in cases where it is deemed unsuitable.
SODIS potential: A novel parameter to assess the suitability of solar water disinfection worldwide
(Elsevier, 2021) Moreno-SanSegundo, José; Giannakis, Stefanos; Samoili, Sofia; Farinelli, Giulio; McGuigan, Kevin G.; Pulgarín, César; Marugán, Javier
This paper studies the worldwide applicability of solar water disinfection (SODIS) technology through a novel parameter: the SODIS potential. This parameter is defined as the inverse ratio between the required exposure time to achieve a four log disinfection of E. coli and the six hours recommended by the standard SODIS protocol. The E. coli inactivation kinetics was predicted by fitting the results under different temperature and incident radiation to a semi-empirical inactivation model, including a synergy term between bacterial stress sources (light/heat). To estimate the SODIS potential, a solar calculator was developed based on the Sun's position, atmospheric extinction, cloud-cover, and elevation. The time-varying total incident radiation available at any location worldwide was estimated for each day along the year during sunlight hours. The time-varying temperature was also estimated from minimum and maximum values, introducing its dynamic variation along with the solar exposure of the water. Both incident radiation and temperature values are input into the kinetic model to estimate the disinfection rate. Based on these values, the number of batch disinfections that can reach the goal of 99.99% bacterial elimination in 1 day and the minimum daily time required to achieve this goal is computed; the latter is finally transformed to the SODIS potential. The results of the study, illustrated as contours indicating the SODIS potential and other relevant indicators overlayed on a world map, confirm that latitude has a significant contribution to the SODIS potential, with the highest values close to the equator. However, the results also highlight the importance of temperature and cloud-cover, with critical differences between equal latitude regions.