Examinando por Autor "Hincapie, M."

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Field-testing solutions for drinking water quality monitoring in low- and middle-income regions and case studies from Latin American, African and Asian countries
(Elsevier, 2023) Pichel, N.; Souza, F. Hymnô de; Sabogal-Paz, L.P.; Shah, P.K.; Adhikari, N.; Pandey, S.; Shrestha, B.M.; Gaihre, S.; Pineda-Marulanda, D.A.; Hincapie, M.; Luwe, K.; Kumwenda, S.; Aguilar-Conde, J.C.; Cortes, M.A.L.R.M.; Hamilton, J.W.J; Byrne, J.A.; Fernandez-Ibañez, P.
This work highlights the need for a global approach to drinking water monitoring that involves facing several critical issues. Field tests that perform to very high standards of indicator microorganisms’ detection and confidence and, at the same time, being available in rural and isolated locations of low-income settings are urgently needed. Commercially available field-testing solutions for Escherichia coli determination based on hydrogen sulfide and defined substrate methods were critically reviewed, considering their capabilities and limitations, compliance against the UNICEF Target Product Profile (TPP), technology performance, availability, and cost. None of the available tests meets the standards set by the UNICEF TPP, the biggest limitation being the requirement of a power source. They need at least 18 to 24 h of incubation, hence they have not significantly decreased the amount of the time needed to complete an assay; and their applicability is generally limited by the sample volume. Additionally, there is still need for more accurate and standardised validation studiesthat open new opportunities for lowcost testing solutions in the field. On the other hand, traditional methods are the only ones legally authorised by national regulations in the case study locations, with a range of resources and technologies limitations. Despite the use of field kits is beginning to gain acceptance, its implementation in the field strongly relies on their availability and cost locally. Most field kits price exceed the maximum of 6 USD set by UNICEF, and they even cost significantly more when acquire from local distributors in developing countries.
Safe drinking water for rural communities using a low-cost household system. Effects of water matrix and field testing
(Elsevier, 2021-11-09) Pichel, N.; Lubarsky, H.; Afkhami, A.; Baldasso, V.; Botero, L.; Salazar, J.; Hincapie, M.; Byrne, J.A.; Fernandez Ibañez, P.
The relationship between turbidity (T) and ultraviolet C (UVC) disinfection is still not clearly understood, as well as no attention has been paid to the contribution of natural organic matter (NOM). The present work assessed the influence of particulate and NOM on the UVC disinfection efficiency in terms of E. coli and MS2 removal at bench collimated beam (CB) and flow-UVC systems, both in the laboratory and in the field (Colombia). The flow-UVC reactor was installed as part of a household water treatment (HWT) system consisting of filtration + UVC disinfection. Tests were performed according to the WHO standards using fine test dust, humic acid (HA), and MS2 and E. coli as microbiological indicators. CB results showed a significant decrease in the inactivation rate of MS2 in the presence of small concentrations of HA (3.5 mg/L), with killing dose increasing a 65%, vs. non-significant effects of turbidity in the range of 0–20 NTU. Following the same trend, in flow-UVC tests the inactivation efficiency of MS2 decreased solely in the presence of HA. At the same HA concentration and flow rate, an increase in turbidity of 17.6 NTU showed a negligible effect. Conversely, in the presence of HA, UVT254 dropped from 88.7% (0 mg/L HA) to 73.3%, reducing MS2 inactivation by 1–2 log-units. Finally, the HWT system could be classified as protective working at flow rates ≤5 L/min. However, in the presence of 3.5 mg/L HA (UVT254 < 75%), it presented a limited protection for viruses.
UVC inactivation of MS2-phage in drinking water – Modelling and field testing
(Elsevier, 2021-08-05) Baldasso , V.; Lubarsky, H.; Pichel, N.; Turolla, A.; Antonelli, M.; Hincapie, M.; Botero, L.; Reygadas, F.; Galdos-Balzategui, A.; Byrne, J.A.; Fernandez-Ibañez, P.
UVC disinfection has been recognised by the WHO as an effective disinfection treatment to provide decentralized potable water. Under real conditions there are still unknowns that limit this application including the influence of suspended solids and natural organic matter. This work aims to investigate the influence of two key parameters, suspended solids and natural organic matter, on the efficiency of UVC disinfection of surface water to achieve the drinking water quality requirements established by the WHO for point of use (POU) technologies. Kaolinite (turbidity agent) and humic acids (HA, model of organic matter) were used in a factorial design of experiments (Turbidity from 0 to 5 NTU, and HA from 0 to 3.5 mg/L) to investigate their effect on UVC inactivation of MS2 phage in surface water. A collimated beam (12 W) and a commercial UVC disinfection flow system (16 W) designed to provide drinking water at households were used. The UVC flow system both in the laboratory and in the field was able to achieve the reduction requirements established by WHO (LRV >3.5 for all tested conditions), confirming the good performance of the studied UVC disinfection system. The results found in the lab were used to establish a numerical model that predicts the disinfection rate constant as a function of water turbidity and transmittance at 254 nm (confidence level>95%). The model permitted to elucidate the critical effect of low concentrations of HA in reducing the inactivation rate by 40% for 3.5 mg/L-HA compared with 0, the non-significant detrimental effect of turbidity lower than 5 NTU, and the lack of synergistic effects between both parameters at these levels. The UVC flow system was also tested in the field, in Tzabalho, Chiapas (Mexico), and Antioquia (Colombia), with spiked MS2 into natural surface water. This investigation opens a potential application to monitor the performance of UVC systems with surface water by monitoring transmittance at 254 nm as a tool to control UVC domestic systems to deliver safe drinking water in a household without the need of expensive and laborious biological monitoring tools.