Estudio de un proceso de nanofiltración combinado con un pretratamiento mediante ultrafiltración para el tratamiento de las aguas residuales de una industria textil

Abstract

[ES] La industria textil es conocida por ser uno de los sectores que generan mayor contaminación de agua a nivel mundial debido a sus diversas técnicas en el procesado de material textil. Además, en función de la etapa de procesado en la que se encuentra, las características y propiedades del agua son diferentes de forma que los procedimientos en su tratamiento también lo serán. De ahí nace la propuesta de este trabajo Fin de Máster. Dado que el agua es un bien tan preciado, escaso y finito, se analizan técnicas individuales y combinadas para la obtención de agua tratada. La técnica principal estudiada es la filtración mediante membranas, más específicamente la nanofiltración, con la cual se pueden obtener corrientes de permeado con elevada separación de parámetros como son color, solidos totales o demanda química de oxígeno, los cuales presentan elevada preocupación medioambiental. A su vez, se estudia la combinación de técnicas previas como la ultrafiltración con la cual se mejoran fenómenos como son la polarización por concentración, factor que altera la integridad de la membrana, reduciendo el flujo de permeado conseguido o, incluso con el tiempo, la rotura de la superficie de la membrana. Durante los diferentes ensayos se varían las condiciones de operación buscando un compromiso entre el objetivo buscado y los menores costes energéticos y económicos posibles a fin de conseguir un proyecto viable. Por último, se caracterizan las corrientes observadas en los ensayos: permeado y rechazo. De esta manera se pueden analizar las prestaciones de las membranas en cuanto a los rechazos obtenidos para los diferentes parámetros. Con las técnicas anteriormente descritas, los rechazos superan el 95% resultando de esta manera métodos válidos para el tratamiento del agua residual textil empleada durante este trabajo.

[EN] The textile industry is known for being one of the sectors that generate the greatest water pollution worldwide due to its various techniques in the processing of textile material. Furthermore, depending on the processing stage it is in, the characteristics and properties of the water are different so that the treatment procedures will also be different. From there comes the proposal of this Master's Thesis. Given that water is such a precious, scarce and finite commodity, individual and combined techniques are analyzed to obtain treated water. The main technique studied is membrane filtration, more specifically nanofiltration, with which permeate streams can be obtained with high separation of parameters such as color, total solids or chemical oxygen demand, which present high environmental concern. At the same time, the combination of previous techniques such as ultrafiltration is studied, with which phenomena such as concentration polarization are improved, a factor that alters the integrity of the membrane, reducing the permeate flow achieved or, even over time, the rupture of the membrane surface. During the different tests, the operating conditions are varied, seeking a compromise between the desired objective and the lowest possible energy and economic costs in order to achieve a viable project. Finally, the currents observed in the tests are characterized: permeate and rejection. In this way, the performance of the membranes can be analyzed in terms of the rejections obtained for the different parameters. With the techniques previously described, rejections exceed 95%, thus resulting in valid methods for the treatment of textile wastewater used during this work.

[CA] The textile industry is known for being one of the sectors that generate the greatest water pollution worldwide due to its various techniques in the processing of textile material. Furthermore, depending on the processing stage it is in, the characteristics and properties of the water are different so that the treatment procedures will also be different. From there comes the proposal of this Master's Thesis. Given that water is such a precious, scarce and finite commodity, individual and combined techniques are analyzed to obtain treated water. The main technique studied is membrane filtration, more specifically nanofiltration, with which permeate streams can be obtained with high separation of parameters such as color, total solids or chemical oxygen demand, which present high environmental concern. At the same time, the combination of previous techniques such as ultrafiltration is studied, with which phenomena such as concentration polarization are improved, a factor that alters the integrity of the membrane, reducing the permeate flow achieved or, even over time, the rupture of the membrane surface. During the different tests, the operating conditions are varied, seeking a compromise between the desired objective and the lowest possible energy and economic costs in order to achieve a viable project. Finally, the currents observed in the tests are characterized: permeate and rejection. In this way, the performance of the membranes can be analyzed in terms of the rejections obtained for the different parameters. With the techniques previously described, rejections exceed 95%, thus resulting in valid methods for the treatment of textile wastewater used during this work.