Context: The lack of dissolved oxygen (DO) in water bodies has become a serious problem for several ecosystems due to drastic changes in their climatic, biological, and physical conditions. The presence of microorganisms, organic matter, and clays, which are carried by landslides and rainwater, affect the process of restoration and transfer of DO in water, thus making it necessary to study how these factors affect the process of DO transfer in water bodies. Method: This work is focused on studying the influence of clays during the DO transfer process in water bodies. To this effect, samples of clays from the region of Paipa, Boyacá, were added in 1, 3 and 5% by weight into the samples of clean water. The aeration process was performed using a constant flow diffusion system. The tests were carried out until the saturation of dissolved oxygen in each of the water samples was obtained. Results: The results show that the presence of clays during the transfer of DO have little influence on bodies of water. However, variations were observed in time intervals of <5 min in which the increase in the percentage of clays favored the transfer of DO. Conclusions: With these results, it is concluded that the presence of clays can generate a beneficial effect during the transfer of DO in bodies of water with a high oxygen deficiency, whereas, for water samples with a relatively high percentage of DO, clays can hinder the DO restoration process.

Objetivo: Evaluar la tasa de transferencia de oxígeno disuelto (OD), en un aireador de superficie de baja velocidad (Low Speed Surface Aerator – LSSA), variando la potencia; y proponer una modificación geométrica de los impulsores, para mejorar la eficiencia de aireación estándar (Standar Aeration Efficiency - SAE). Metodología: Se modeló un LSSA a través de software CAD, y se construyeron 3 prototipos de LSSA, mediante un proceso de impresión 3D, modificando la geometría original del impulsor. Luego se realizaron ensayos a escala piloto, usando los LSSA acoplados a un motorreductor capaz de generar 210 RPM. Finalmente, se determinaron los coeficientes de transferencia de oxígeno, y la eficiencia de aireación en el agua, de los LSSA, por medio de un modelo matemático. Resultados: A partir de las proyecciones obtenidas, se estableció que la modificación geométrica propuesta, incrementa la SAE en un 20.3% y 29.8% para potencias de 1 y 2 vatios (W), respectivamente; manteniendo casi constante la tasa de transferencia estándar de oxígeno (Standar Oxygen Transfer Rate - SOTR); además, la forma geométrica y disposición de los impulsores propuesta, parece favorecer el tiempo de contacto entre la fase gaseosa (aire) y la fase liquida (agua), mejorando el tiempo de permanencia de las burbujas atrapadas, evidencia representada en los coeficientes kLa (h-1). Conclusiones: De acuerdo con los resultados, se puede inferir que estos aireadores de tipo LSSA, pueden ser optimizados con un diseño más eficiente, permitiendo reducir el consumo energético asociado a su funcionamiento, sin penalizar la transferencia de OD.

In this work, the effect of radon gas removal was studied for thermal water samples subjected to aeration and dissolved oxygen (DO) transfer processes. The prototype used in this work consisted of the application of a diffusion aeration system, usually used in water treatment processes, and the incorporation of a camera with the presence of LR-115 passive detectors, used for the measurement of radon gas. The Pylon ABC-6 active measurement method was used as a reference mechanism for radon gas concentration, while the dissolved oxygen measurement was measured simultaneously using a digital oximeter. The results obtained show that the DO transfer process is accompanied by an optimal removal of the radon gas present in the water samples, with a reception data of 1.5 ± 0.2 kBq·m-3, 61% of the value initially obtained. These data show that DO transfer processes have a great contribution to the removal of radon gas present in water bodies.

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