Browsing by Author "Tapia Flores, Natalia F."

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    Evaluation of sedum species as potential drivers for plant microbial fuel cells in green roof of a semi-arid environment
    (2016) Tapia Flores, Natalia F.; Vargas Cucurella, Ignacio Tomás; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    Plant microbial fuel cells (PMFCs) son sistemas bioelectroquímicos que utilizan los exudados de las raíces para transformar la energía química en energía eléctrica. PMFCs pueden ser desarrollados en sitios como humedales y cubiertas vegetales. Sin embargo, a diferencia de los humedales, las cubiertas vegetales permiten implementar estos sistemas en una mayor variedad de lugares. Los beneficios que poseen las cubiertas vegetales, tales como la reducción de los caudales de escorrentía, el mejoramiento de la calidad del aire, el incremento de la biodiversidad, entre otros, ha expandido esta tecnología a regiones distintas para las que fueron concebidas inicialmente. Por ende, en climas semiáridos donde la temperatura y las condiciones de agua son diferentes, especies distintas de plantas son requeridas. Entre las primeras plantas probadas en cubiertas vegetales de regiones semiáridas, se encuentra Sedum spp., plantas suculentas caracterizadas por su bajo requerimiento hídrico y resistencia a la sequía. Por lo tanto, Sedum emerge como un interesante candidato para ser usado en PMFC, permitiendo su implementación en cubiertas vegetales construidas en climas semiáridos. Este estudio muestra que Sedum es un tipo de vegetación factible de utilizar en PMFCs. Entre las especies evaluadas, S. hybridum mostró la más alta densidad de potencia (92 μW m-2) seguida por S. rupestre (15.5 μW m-2), mientras que S. spurium presentó el peor funcionamiento. La pirosecuenciación utilizada para caracterizar la comunidad microbiana desarrollada en los electrodos de tres reactores seleccionados, reveló que miembros de la familia Micrococcaceae predominan en el ánodo de S. hybridum. En contraste, miembros de la familia Comamonadaceae, seguida por el género Paracoccus y Ardenscatena, fueron los principales grupos observados en los ánodos de S. rupestre y S. spurium. El análisis microbiano sugiere que la implementación de PMFCs podría no alterar la microbiota del suelo. Finalmente, la relación observada entre contenido de agua en el suelo y el voltaje generado, tanto en los experimentos en el laboratorio como en el laboratorio de cubiertas vegetales, podría ser útil para expandir esta tecnología y desarrollar bio-sensores de bajo costo para monitorear la irrigación en ambientes semiáridos.
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    Perchlorate and chlorate assessment in drinking water in northern Chilean cities
    (2023) Muñoz Arango, Diana Carolina; Torres Rojas, Felipe Ernesto; Tapia Flores, Natalia F.; Vega Muñoz, Marcela Natalia; Alvear, Cristóbal; Pizarro, Gonzalo; Pastén González, Pablo Arturo; Cortés Arancibia, Sandra; Vega Contreras, Alejandra Soledad; Calderón, Raúl; Nerenberg, Robert; Vargas, Ignacio; CEDEUS (Chile)
    Perchlorate and chlorate are endocrine disruptors considered emerging contaminants (ECs). Both oxyanions are commonly associated with anthropogenic contamination from fertilizers, pesticides, explosives, and disinfection byproducts. However, the soils of the Atacama Desert are the most extensive natural reservoirs of perchlorate in the world, compromising drinking water sources in northern Chile. Field campaigns were carried (2014–2018) to assess the presence of these ECs in the water supply networks of twelve Chilean cities. Additionally, the occurrence of perchlorate, chlorate and other anions typically observed in drinking water matrices of the Atacama Desert (i.e., nitrate, chloride, sulfate) was evaluated using a Spearman correlation analysis to determine predictors for perchlorate and chlorate. High concentrations of perchlorate (up to 114.48 μg L−1) and chlorate (up to 9650 μg L−1) were found in three northern cities. Spatial heterogeneities were observed in the physicochemical properties and anion concentrations of the water supply network. Spearman correlation analysis indicated that nitrate, chloride, and sulfate were not useful predictors for the presence of perchlorate and chlorate in drinking water in Chile. Hence, this study highlights the need to establish systematic monitoring, regulation, and treatment for these EC of drinking water sources in northern Chilean cities for public health protection.
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    Synthetic greywater treatment using a scalable granular activated carbon bioelectrochemical reactor
    (Elsevier, 2024) Gallardo Bustos, Carlos; Tapia Flores, Natalia F.; Vargas Cucurella, Ignacio Tomás; CEDEUS (Chile)
    Greywater reuse has emerged as a promising solution for addressing water shortages. However, greywater needs treatment before reuse to meet the required water quality standards. Conventional wastewater treatment technologies are unsuitable for recreating highly decentralized domestic greywater. This study evaluated bioelectrochemical reactors (BERs) with granular activated carbon (GAC) as a sustainable alternative for developing decentralized and low-cost biological treatment systems. BERs using GAC as the anode material and conventional GAC biofilters (BFs) for synthetic greywater treatment were operated in batch mode for 110 days in two stages: (i) with polarized anodes at −150 mV vs. Ag/AgCl and (ii) as a microbial fuel cell with an external resistance of 1 kΩ. Anode polarization produced an electrosorption effect, increasing the ion removal of the BERs. Power production during the operation and cyclic voltammetry tests of the extracted granules revealed electrochemically active biofilm development on the BERs. Although low power density (0.193 ± 0.052 µW m−3) was observed in BERs, they showed a similar performance in sCOD removal (BER = 91.6–89.6 %; BF = 96.2–93.2 %) and turbidity removal (BER = 81–82 %; BF = 30–62 %) to BFs that used 50 % aeration. Additionally, scanning electron microscopy of sampled granules showed higher biomass formation in BER granules than in BF granules, suggesting a higher contribution of sessile (vs. planktonic) cells to the treatment. Thus, the results highlight the synergistic removal effect of the GAC-based BER. The scalable design presented in this study represents a proof-of-concept for developing BERs to use in decentralized greywater treatment systems.