Avaliação e comparação do desempenho de um sistema de membranas de micro/nano filtração com o sistema de osmose inversa para diferentes níveis de concentração de saia de águas salobras da comunidade de Uruçu em São João do Cariri-PB.

Abstract

The membranes processing during water treatment has been one of the alternatives for production of drinkable water for the benefit of communities in semi-arid regions of Northeastern Brazil. The objective of this work is studying the performance of a system of water treatment with membranes of microfiltration (MF) and_nanofiltration (NF), in order to access their desalination potential and to compare their permeated quality with that of the reverse osmosis system. The system will contain two membranes elements, one of those is a Dow Chemical Company - Filmtec model NF90 - 4040 with an area of 7,6 m2, and the other is composed of a microfiltration membrane made of hollow fibers with measures of diameter 0,95 mm and area of 14 m2 .whose capacity of production are of 500 L/h and 250 L/h, respectively. The use of a well-chosen pre-treatment system is a key element to prevent incrustations in nanofiltration. Among the different possibilities of pre-treatment systems, microfiltration arises as the most compatible with (NF). The study was carried out in eight parts with a 2 h duration for each part at intervals of 10 minutes when were collected samples of the feeding, concentrated and permeated from the system. As an instance of comparison with the reverse osmosis system, a salty water well was chosen, with a 2479,7 mg/L TDS, has been being desalinized by a reverse osmosis system located at the village of Urucu, in Sao Joao do Cariri - PB. The salt concentration profiles of the micro - nanofiltration and reverse osmosis systems were done through physico-chemical analysis reaching an average rejection rate for calcium of 82,74% in the micro -nanofiltration system and a rejection rate of 99% for reverse osmosis. It was observed that the chemical purity is a maintenance step which is searched for keeping the quality and production of the permeated within the acceptable established standards.