Examinando por Autor "Gaihre, S."

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Automated household-based water disinfection system for rural communities: Field trials and community appropriation
(Elsevier, 2025-05-23) Hincapié, M.; Galdós-Balzategui, A.; Freitas, B.L.S.; Reygaldas, F.; Sabogal-Paz, L.P.; Pichel, N.; Botero, L.; Montoya, L.J.; Galeano, L.; Carvajal, G.; Lubarsky, H.; Ng, K.Y.; Price, R.; Gaihre, S.; Byrne, J.A.; Fernández-Ibáñez, P.
This research involved a pilot field trial of household-based water treatment and storage for potable water in rural communities of Colombia and Mexico. Through co-creation with the communities, key parameters were considered when designing the systems, including the efficiency of disinfection, the provision of a sufficient volume of treated water, variability of the raw water quality and access to freshwater sources. The water treatment systems were automated with electronic controllers. They consisted of a sedimentation tank (bottom), a treatment unit (pre-filtration followed by UVC disinfection), a pump to move the treated water to a second elevated tank for storing the treated water (150 L or 250 L), and a small distribution network that provided water inside the home by gravity (kitchen and bathroom taps). They were installed at households in rural communities of Colombia (52 systems) and Mexico (187 systems) and the performance was evaluated over 12 consecutive months. Efficiency was evaluated using standard microbial and physicochemical water quality parameters. Treated water turbidity was below the World Health Organization (WHO) recommendation (< 5 NTU) in >97 % of the samples in Colombia and 98.9 % in Mexico. The treatment reduced Escherichia coli to potable levels in all cases, regardless of the initial microbiological load and the variation of the raw water quality. In some cases, an increase in E. coli values was detected in the distribution network within the households (post-storage), although not statistically significant, they represented a ‘moderate risk’. The health risk associated with the water was reduced to ‘low risk’ in >80 % of the treated water samples vs. <10 % before treatment. After 12 months of operation, the household water treatment and storage systems (HWTSs) remained effective for the provision of potable water.
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.