Análisis técnico de la instalación de un biodigestor anaerobio para la producción de biogás a partir de los lodos provenientes de una planta de tratamiento de aguas servidas.
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Date
2019
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Universidad de Concepción
Abstract
La planta de tratamiento de aguas servidas (PTAS) de la comuna de Chillán (Región Ñuble) produce alto contenido de lodo como producto del tratamiento de las aguas, se espera que aumente por el rápido crecimiento de la población, y que actualmente su disposición final es en monocultivos. Para aprovechar más el recurso se evaluó instalar un biodigestor anaerobio de tipo mezcla completa de flujo continuo, donde se obtendría energía térmica para calefaccionar el reactor y energía eléctrica para utilizar dentro de la planta además de lograr estabilizar el lodo. Para poder realizar la presente tesis, se trabajó en laboratorio para analizar el contenido de sólidos totales, sólidos volátiles y alcalinidad del lodo generado en la PTAS. Además se utilizaron datos diarios de la planta como temperatura, pH y caudal de las aguas servidas, entre otros. Se realizaron balances de masa y energía para conocer la producción de biogás, reducción de sólidos, además de generación de energía térmica y eléctrica. Dentro de los resultados obtenidos el contenido de sólidos totales estuvo dentro del rango esperado según el tipo de sustrato de 4,5 a 6,0% con alto porcentaje de materia orgánica (95% -97%). En relación a la alcalinidad el rango propuesto para este tipo de sustrato no superó el 0,13 lo que produciría la desestabilización en el sistema de digestión anaerobia. De acuerdo a los balances realizados, se estimó una producción de biogás de674,4 m³ día-1 y una generación total de energía de 153,93 kW día⁻¹. La energía térmica producida es de 75,10 kW día-1, suficiente desde noviembre hasta marzo para autosustentar las necesidades térmicas del biodigestor, y además la energía eléctrica generada estimada fue de 54,95 kW día⁻¹. El lodo se reduciría cerca del 13,00%, los sólidos totales se reducirían 70,96% y sólidos volátiles 69,03% logrando la estabilización, reducción del contenido de patógenos y olores.
The wastewater treatment plant Chillán (Ñuble region) produces high contents of sluge as a result of water treatment, which is expected to increase due to the fast growing population and its current final disposition is in monocultures. To take more advantage of this resource, continuous stirred tank reactor such as an anaerobic digester was evaluated, from which thermal energy would be obtained to heat the reactor and also electric energy would be generated to be used inside the plant, meanwhile the sludge is stabilized. In order to carry out this thesis, a laboratory work was executed to analyze the content of total solids, volatile solids and alkalinity. In addition, daily information of the plant was used, such as temperature, pH, flow, among others. Mass and energy balances were made to estimate the biogas production, reduction of solids and both thermal and electrical energy generation. From the obtained results, the content of total solids was within the range of 4,5% to 6,0% with a high percentage of organic matter (95% -97%), and in terms of alkalinity the range determined for this type of substrate did not exceed 0,13, which would cause destabilization in an anaerobic digestion system. From mass and energy balance, the results were: the volume of potential biogas generation was estimated in 674,4 m³ in which 153,93 kW day⁻¹ are produced. Thermal energy would be enough to self-regulate temperature in the biodigester from November to March. The electric power was 54,95 kW day⁻¹. Sludge volume would be reduced near 13,00%, total solids would be reduced 70,96% and volatile solids 69,03%, achieving stabilization and reducing the content of pathogens and odors.
The wastewater treatment plant Chillán (Ñuble region) produces high contents of sluge as a result of water treatment, which is expected to increase due to the fast growing population and its current final disposition is in monocultures. To take more advantage of this resource, continuous stirred tank reactor such as an anaerobic digester was evaluated, from which thermal energy would be obtained to heat the reactor and also electric energy would be generated to be used inside the plant, meanwhile the sludge is stabilized. In order to carry out this thesis, a laboratory work was executed to analyze the content of total solids, volatile solids and alkalinity. In addition, daily information of the plant was used, such as temperature, pH, flow, among others. Mass and energy balances were made to estimate the biogas production, reduction of solids and both thermal and electrical energy generation. From the obtained results, the content of total solids was within the range of 4,5% to 6,0% with a high percentage of organic matter (95% -97%), and in terms of alkalinity the range determined for this type of substrate did not exceed 0,13, which would cause destabilization in an anaerobic digestion system. From mass and energy balance, the results were: the volume of potential biogas generation was estimated in 674,4 m³ in which 153,93 kW day⁻¹ are produced. Thermal energy would be enough to self-regulate temperature in the biodigester from November to March. The electric power was 54,95 kW day⁻¹. Sludge volume would be reduced near 13,00%, total solids would be reduced 70,96% and volatile solids 69,03%, achieving stabilization and reducing the content of pathogens and odors.
Description
Tesis presentada para optar al título de Ingeniero Ambiental
Keywords
Biogas, Ciudades y Comunidades Sostenibles, Aguas Servidas - Purificación - Chile - Chillán, Digestión Anaeróbica (Purificación de Aguas Servidas), Agua Limpia y Saneamiento, Lodo de Aguas Servidas