Rosa Amalia González Rivero

In this research, several SO2 removal alternatives were evaluated for the treatment of gaseous effluents generated by the "Carlos Manuel de Céspedes" power plant in Cienfuegos to be use in gaseous stream to Ulva lettuce intensive culture. A low-cost sensor was used to monitor the gas concentration during the proposed methods. The sensor was previously calibrated and a linear regression model with a coefficient of determination of 0,9926 was obtained. The alternatives evaluated were adsorption with activated carbon, absorption with calcium hydroxide and absorption with seawater. The removal was evaluated at three levels SO2 concentration. In addition, the parameters pH, salinity and alkalinity were determined to a seawater sample from the Bay of Cienfuegos and with which the experiments were carried out. The values obtained were 8,17±0,003; 26,50±0,10 ups and 171,67±1,03 mg/L respectively, which confirms its good performance for gas removal. The three methods studied showed satisfactory results for SO2 removal. The seawater absorption experiment was the most efficient alternative, achieving the lowest final concentrations in the shortest time. En esta investigación se evaluaron varias alternativas de remoción de SO2 para el tratamiento de los efluentes gaseosos generados por la central termoeléctrica «Carlos Manuel de Céspedes» de Cienfuegos para su uso en corriente gaseosa al cultivo intensivo de la lechuga Ulva. Se utilizó un sensor de bajo costo para monitorear la concentración de gases durante los métodos propuestos. El sensor fue previamente calibrado y se obtuvo un modelo de regresión lineal con un coeficiente de determinación de 0,9926. Las alternativas evaluadas fueron adsorción con carbón activado, absorción con hidróxido de calcio y absorción con agua de mar. La eliminación se evaluó a tres niveles de concentración de SO2. Además, se determinaron los parámetros pH, salinidad y alcalinidad a una muestra de agua de mar procedente de la Bahía de Cienfuegos y con la cual se realizaron los experimentos. Los valores obtenidos fueron 8,17±0,003; 26,50±0,10 ups y 171,67±1,03 mg/L respectivamente, lo que confirma su buen desempeño para la remoción de gases. Los tres métodos estudiados mostraron resultados satisfactorios para la eliminación de SO2. El experimento de absorción en agua de mar fue la alternativa más eficiente, alcanzando las concentraciones finales más bajas en el menor tiempo. Nesta investigação, foram avaliadas várias alternativas de remoção de SO2 para o tratamento de efluentes gasosos gerados pela central eléctrica “Carlos Manuel de Céspedes”, em Cienfuegos, para serem utilizados em fluxo gasoso para a cultura intensiva de alface Ulva. Foi utilizado um sensor de baixo custo para monitorizar a concentração de gás durante os métodos propostos. O sensor foi previamente calibrado e obteve-se um modelo de regressão linear com um coeficiente de determinação de 0,9926. As alternativas avaliadas foram adsorção com carvão ativado, absorção com hidróxido de cálcio e absorção com água do mar. A remoção foi avaliada em três níveis de concentração de SO2. Além disso, foram determinados os parâmetros pH, salinidade e alcalinidade a uma amostra de água do mar da Baía de Cienfuegos com a qual se realizaram as experiências. Os valores obtidos foram de 8,17±0,003; 26,50±0,10 ups e 171,67±1,03 mg/L respetivamente, o que confirma o seu bom desempenho na remoção de gases. Os três métodos estudados apresentaram resultados satisfatórios para a remoção de SO2. O experimento de absorção com água do mar foi a alternativa mais eficiente, alcançando as menores concentrações finais no menor tempo.

Low-cost sensors provide an affordable alternative to monitor environmental parameters with acceptable performance. There is a substantial amount of literature where low-cost sensors are compared with high-end reference measurements. However, not all organizations have access to such reference infrastructure. We propose low-cost calibration methods for temperature, relative humidity, and CO₂ to allow them to collect their own reliable data. These methods are based on simple techniques and procedures that allow temperature calibration to be achieved in the range of 0 to 50 °C, relative humidity from 0 to 90%, and CO₂ between 0 and 1100 ppm. The materials used to create the calibration setups can be purchased online, at hardware stores, and in pharmacies. The reliability of the calibration methods was evaluated using several indicators, such as the airtightness of the calibration box, similarity with the factory calibration, similarity with the reference, similarity between different sensors, replicability of the calibration method, and the similarity with a golden standard. In addition, the results of the low-cost calibration methods were compared with the more advanced calibration methods. A short measurement campaign in the city of Santa Clara, Cuba, demonstrated that such calibrations transform in-house developed monitoring systems into valid low-cost scientific instruments for decision-making. This work creates opportunities for institutions and researchers hosted in low- and mid-income countries to build and validate their own equipment to reliably solve local problems.