Desempenho de um sistema de purificação e dessalinização de águas salobras através de membranas de ultrafiltração/osmose inversa.

Abstract

This work aims to evaluate the performance of a hybrid system of ultrafiltration/reverse osmosis membranes, for the purposes of brackish water treatment. Several measurement variables were monitored, such as; permeate and concentrate flows, inlet and outlet pressures of the filter and membrane elements in order to study the performance of the system for different levels of concentrations of dissolved salts from mixtures of treated water (T.W.) with well water (W.W.) under different operating pressure gradients. In order to characterize the system by varying the operating pressures, experiments were carried out with 4,0 kgf/cm² and 8,0 kgf/cm² for the treated water system and 6,0 kgf/cm², 8,0 kgf/cm² and 10,0 kgf/cm² for the system with well water, among these operating pressures, 8,0 kgf/cm² showed better results. The system was adjusted under this pressure of 8,0 kgf /cm² by varying the concentration (75% T.W. + 25% W.W., 50% + 50% and 25% T.W. + 75 W.W.). According to the results obtained, it was observed that the potential for the extraction of salts depended on the variation of operating pressure. As shown by the percentage of Cl- ion removal of -2,24%, 93,76%, 94,79%, 96,25% and 96,65% for pressures 4,0 kgf/cm², 8,0T.W. kgf/cm², 6,0 kgf/cm², 8,0W.W. kgf/cm² and 10,0 kgf/cm² respectively. The results of the bacteriological analyzes were studied, before and after the chemical cleaning of the membrane elements, showing satisfactory results. It was observed that the cost of the water produced by the system depended on the level of dissolved salts in the feed water and the operating pressure. The operating pressure of 8,0 kgf/cm² according to the data obtained in terms of cost and recovery showed the best results.