Examinando por Autor "Lubarsky, H."

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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.
Photoelectrocatalitic degradation of pharmaceuticals and inactivation of viruses in water with tungsten oxide electrons
(Elsevier, 2022-05-24) Tolosana-Moranchel, A.; Pichel, N; Lubarsky, H.; Byrne, J.A.; Fernandez-Ibañez, P.
Electrochemically assisted photocatalysis (EAP) is one approach to overcome the fast recombination rates in photocatalysis and increase the quantum efficiency to produce ROS. In comparison to TiO2, tungsten trioxide (WO3) can utilize UV and visible photons and with EAP the external bias can be used to drive the reduction pathway. In this work WO3 electrodes were prepared hydrothermally on FTO. Vertically grown WO3 nanoplate-like structures were thoroughly characterized. The WO3 photoanodes improved photocurrent response compared to P25 and a visible response was measured. These results were attributed to smaller charge transfer resistance and their morphology. The activity of the photoanodes was assessed on the EAP degradation of sulfamethoxazole and MS2 bacteriophage. WO3 yielded ten times higher degradation rates for sulfamethoxazole (2.21 · 10−6 mmol cm−2 min−1) compared to P25. WO3 also yielded the fastest MS2 inactivation rate. A rapid 5-log removal was achieved in 6 min with WO3 that maintained activity over 5 cycles.
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.