Bases experimentales para la utilización de micro-nano burbujas en un contexto de remediación lacustre.
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Date
2025
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Publisher
Universidad de Concepción
Abstract
Gran parte de los sistemas fluviales y lacustres, especialmente con influencia urbana, presentan un estado trófico deficiente. Estos sistemas son complejos y poseen procesos biogeoquímicos internos más lentos que la presión antrópica ejercida sobre ellos, por lo que, el estudio de procesos de restauración internos se vuelve urgente para la disponibilidad hídrica. Este estudio explora el potencial de las micro nano burbujas (MNB) mediante un estudio de mesocosmos, utilizando agua de un lago urbano altamente eutrofizado en la ciudad de Concepción, Chile, con el objetivo de: (i) analizar los tiempos de aplicación que permitan modificar significativamente las expresiones fisicoquímicas asociadas al proceso de eutrofización, (ii) caracterizar las respuestas de las comunidades zooplanctónicas y (iii) proponer recomendaciones para extrapolar en un sistema natural. Las MNB fueron generadas mediante cavitación hidrodinámica (CH) utilizando el método Venturi, un método de bajo costo, y que ha sido utilizado en distintas áreas productivas y de desarrollo. Se aplicó MNB en estanques experimentales de 150 L, durante intervalos de tiempo de 10, 15, 20, 30, 45 y 60 minutos, donde se evaluaron variables fisicoquímicas (oxígeno disuelto, temperatura, ORP, conductividad, pH), nutrientes (nitrato, nitrito y cloruro) y comunidades zooplanctónicas. Adicionalmente, se agregó una toma de muestra 24 horas posterior a la aplicación, evaluándose DBO5 y turbidez, más las variables fisicoquímicas ya mencionadas. Durante los 60 min de aplicación se observaron aumentos significativos de pH, OD y temperatura a partir de T30, con sobresaturación de OD y estabilización posterior; el ORP mostró variaciones marcadas entre tiempos. Mientras que, a las 24 horas, se evidenció una disminución de la DBO5 y del OD. Sin embargo, las fluctuaciones de temperatura, OD y la variabilidad en la dinámica de los nutrientes indican la necesidad de realizar estudios a más largo plazo (por ejemplo, ciclos de 60 minutos mantenidos durante semanas o meses) para evaluar los posibles impactos ecológicos y la escalabilidad de este método en entornos naturales. Los tiempos de aplicación no deben exceder una hora, ya que las variables medidas tienden a estabilizarse más allá de este punto, lo que reduce la eficacia del tratamiento a escala mesocosmos. La comunidad zooplanctónica (6 taxa, 5 órdenes, 4 familias) pasó de Mesocyclops y nauplios dominantes en T0 a Keratella cochlearis dominante en T60; los índices comunitarios (Shannon, Simpson y Equidad) reflejaron el colapso de la comunidad sensible y la sustitución por un rotífero tolerante. Sin embargo, se requieren mayores experimentos en plazos más extensos y exposiciones controladas.
Many river and lake systems, especially those influenced by urban areas, are in poor trophic condition. These systems are complex and undergo internal biogeochemical changes more slowly than those caused by anthropogenic pressure, making the study of internal restoration processes urgent for water availability. This study explores the potential of micro nano bubles (MNBs) through a mesocosm study, using water from a highly eutrophicated urban lake in the city of Concepción, Chile, with the aim of: (i) analyzing the application times that allow for significant modification of the physicochemical expressions associated with the eutrophication process, (ii) characterize the responses of zooplankton communities, and (iii) propose recommendations for extrapolation to a natural system. MNBs will be generated by hydrodynamic cavitation (HC) using the Venturi perforate plates method, which is a low-cost method that has been used in different productive and development areas. MNB was applied in 150 L ponds for intervals of 10, 15, 20, 30, 45, and 60 minutes, while long-term analyses (0 minutes, 60 minutes, and 24 hours later) were integrated. Physicochemical variables (dissolved oxygen, temperature, ORP, conductivity, pH), nutrients (nitrate, nitrite, and chloride), and zooplankton were evaluated. During the 60 min of application, significant increases in pH, DO, and temperature were observed starting at T30, with DO supersaturation and subsequent stabilization; ORP showed marked variations between times. However, temperature fluctuations and variability in nutrient dynamics indicate the need for longer-term studies (e.g., 60-minute cycles maintained for weeks or months) to assess the potential ecological impacts and scalability of this method in natural environments. Application times should not exceed one hour, as the measured variables tend to stabilize beyond this point, reducing the effectiveness of the treatment at the mesocosm scale. The zooplankton community (6 taxa, 5 orders, 4 families) changed from Mesocyclops and nauplii dominant at T0 to Keratella cochlearis dominant at T60, with extreme homogenization at T24 and a one-off recovery of richness in one replicate; Community indices (Shannon, Simpson, equity) reflected the collapse of the sensitive community and its replacement by a tolerant rotifer. However, further experiments are required over longer periods and controlled exposures.
Many river and lake systems, especially those influenced by urban areas, are in poor trophic condition. These systems are complex and undergo internal biogeochemical changes more slowly than those caused by anthropogenic pressure, making the study of internal restoration processes urgent for water availability. This study explores the potential of micro nano bubles (MNBs) through a mesocosm study, using water from a highly eutrophicated urban lake in the city of Concepción, Chile, with the aim of: (i) analyzing the application times that allow for significant modification of the physicochemical expressions associated with the eutrophication process, (ii) characterize the responses of zooplankton communities, and (iii) propose recommendations for extrapolation to a natural system. MNBs will be generated by hydrodynamic cavitation (HC) using the Venturi perforate plates method, which is a low-cost method that has been used in different productive and development areas. MNB was applied in 150 L ponds for intervals of 10, 15, 20, 30, 45, and 60 minutes, while long-term analyses (0 minutes, 60 minutes, and 24 hours later) were integrated. Physicochemical variables (dissolved oxygen, temperature, ORP, conductivity, pH), nutrients (nitrate, nitrite, and chloride), and zooplankton were evaluated. During the 60 min of application, significant increases in pH, DO, and temperature were observed starting at T30, with DO supersaturation and subsequent stabilization; ORP showed marked variations between times. However, temperature fluctuations and variability in nutrient dynamics indicate the need for longer-term studies (e.g., 60-minute cycles maintained for weeks or months) to assess the potential ecological impacts and scalability of this method in natural environments. Application times should not exceed one hour, as the measured variables tend to stabilize beyond this point, reducing the effectiveness of the treatment at the mesocosm scale. The zooplankton community (6 taxa, 5 orders, 4 families) changed from Mesocyclops and nauplii dominant at T0 to Keratella cochlearis dominant at T60, with extreme homogenization at T24 and a one-off recovery of richness in one replicate; Community indices (Shannon, Simpson, equity) reflected the collapse of the sensitive community and its replacement by a tolerant rotifer. However, further experiments are required over longer periods and controlled exposures.
Description
Tesis presentada para optar al grado de Magíster en Ciencias Ambientales.
Keywords
Lagos Chile, Zonas urbanas, Eutrofización