Examinando por Autor "Pichel, N."

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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.
Continuous solar photo-Fenton for wastewater reclamation in operational environment at demonstration scale
(Elsevier, 2023-07-20) Gualda-Alonso, E.; Pichel, N.; Soriano-Molina, P.; Olivares-Ligero, E.; Cadena-Aponte, F.X.; Agüera, A.; Sánchez Pérez, J.A.; Casas López, J.L.
For the first time, a continuous flow solar photo-Fenton demonstration plant has been assessed for wastewater reclamation according to the EU 2020/741 regulation. The treated water qualities achieved under two operating strategies (acidic and neutral pH) in a 100-m2 raceway pond reactor were explored in terms of liquid depth, iron source, reagent concentrations, and hydraulic residence time over three consecutive days of operation. The results obtained at acidic pH showed removal percentages of contaminants of emerging concern (CECs) > 75% and water quality classes B, C and D according to EU regulation at both assessed operating conditions, with treatment capacities up to 1.92 m3 m-2 d-1. At neutral pH with ferric nitrilotriacetate (Fe3+-NTA), 50% of CEC removal and only water quality class D were achieved with the most oxidizing condition assessed, giving a treatment capacity of 0.80 m3 m-2 d-1. The treatment capacities obtained in this work, which have never been achieved with solar water treatments, demonstrate the potential of this technology for commercial-scale application.
Demonstrating the feasibility of a novel solar photo-Fenton strategy for full-scale operationalization according to EU 2020/741 disinfection targets for water reuse
(Elsevier, 2023-07-24) Pichel, N.; Belachqer El Attal, S.; Soriano Molina, P.; Sanchez Perez, J.A.
A novel solar photo-Fenton strategy based on the simultaneous supply of Fe3+-NTA, H2O2 and NaOCl has been proven, for the first time, to meet the more restricted disinfection requirements set by the EU 2020/741 Regulation on wastewater reuse. Operational settings near to real conditions were considered to encourage future operationalization at full-scale. This novel approach, operating in continuous flow mode, has proceeded to effectively reduce Escherichia coli, Clostridium perfringens and MS2 coliphage, along with total coliforms (TC) and Enterococcus faecalis load, with total inactivation levels ≥ 5 log-units for E. coli, E. faecalis, and MS2, 4 log-units TC and 3.5 log-units C. perfringens. Despite validation targets for coliphages (≥6 log-units) and C. perfringens (≥5 log-units) were not attained, it appears feasible by lightly increasing NaOCl concentration. Additionally, the remaining E. coli load in the photoreactor's effluent was within the strictest EU 2020/741 monitoring threshold (≤10 CFU/100 mL). Therefore, the rearrangement of oxidants concentration should be further explored, as this new strategy is shown as a promising technology to address the challenge disinfection presented for full-scale operation. This showing a high potential to produce water that complies with the highest EU 2020/741 standards (Class A), with no additional adjustments required to produce water within the Classes with fewer restrictions (B, C, and D).
Exploring microbial dynamics in a pilot-scale microalgae raceway fed with urban wastewater: insights into the effect of operational variables
(Elsevier, 2024-09-06) Nordio, R.; Belachqer-El Attar, S.; Clagnan, E.; Sánchez-Zurano, A.; Pichel, N.; Viviano, E.; Adani, F.; Guzmán, J.L.; Acien, G.
Microalgae-based wastewater treatment is a promising technology efficient for nutrient recycling and biomass production. Studies continuously optimize processes to reduce costs and increase productivity. However, changes in the operational conditions affect not only biomass productivity but the dynamics of the overall microbial community. This study characterizes a microalgae culture from an 80 m2 pilot-scale raceway reactor fed with untreated urban wastewater. Operational conditions such as pH, dissolved oxygen control strategies (On-off, PI, Event-based, no control), and culture height were varied to assess microbial population changes. Results demonstrate that increased culture height significantly promotes higher microalgal and bacterial diversity. pH, dissolved oxygen and culture height highly affects nitrifying bacteria activity and nitrogen accumulation. Furthermore, the system exhibited high disinfection capability with average Logarithmic Reduction Values (LRV) of 3.36 for E. coli and 2.57 for Clostridium perfringens. Finally, the fungi species detected included Chytridiomycota and Ascomycota, while purple photosynthetic bacteria were also found in significant abundance within the medium.
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.
UVC-LED assisted photo-Fenton/peroxydisulfate processes for microcontaminant and bacteria removal in a continuous flow reactor according to EU 2020/741
(Elsevier, 2024-05-22) Benzaquén, T.B.; Pichel, N.; Soriano-Molina, P.; Casas López, J.L.; Li Puma, G.; Sánchez Pérez, J.A.
Bacteria inactivation (Escherichia coli (E. coli), total coliforms, Clostridium perfringens (C. perfringens)) and simultaneous removal of ubiquitous microcontaminants in actual municipal wastewater treatment plant secondary effluents was investigated at neutral pH using the UVC-LED assisted photo-Fenton reaction system operated in continuous flow. E. coli concentration ≤ 10 CFU/100 mL and 38 % microcontaminant removal was achieved in the reaction system at a hydraulic residence time of 30 min. UVC light alone and UVC light combined with an oxidant source (hydrogen peroxide, H2O2, or peroxydisulfate, S2O82−) were found to have a predominant effect on disinfection, meeting the EU 2020/741 validation (≥5 log10 reduction) and monitoring (≤10 CFU/100 mL) targets for both E. coli and C. perfringens after 30 min of treatment in batch mode. However, in the presence of either 0.05 or 0.1 mM of ferric nitrilotriacetate (Fe3+-NTA) the bacteria inactivation kinetics decreased due to reduced UVC light penetration along the water depth. In contrast, microcontaminant removal was accelerated using 0.05 or 0.1 mM of Fe3+-NTA and 1.47 mM H2O2. Overall, the results revealed that the treatment conditions favouring microcontaminant removal hindered disinfection and vice versa, and that the disinfection levels of C. perfringens (≤102 CFU/100 mL) reached in the batch mode experiments could not be attained under the continuous flow regime. This points out the need of performing disinfection experiments under continuous flow operation, as shown in the present study to determine the disinfection performance of UVC-LED assisted photo-Fenton reaction systems.