A large amount of non-biodegradable inorganic salts having low to high potential of hazards is discharged every year in water bodies by various industrial activities. The salts hazardous depend on nature and their concentration in water. Sodium sulfate is one of them. Although the sulfate's health effect is relatively short-term, it is acute (diarrhea) and a substantial decrease of sulfate content in drinking water is recommendable. It is mainly discharged in to water bodies via commodity

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... t like detergent or via industrial activity manufacturing kraft paper, glass, sodium salts, ceramic glazes, pharmaceuticals, processing textile fibers dyes, Aluminium silicate, rayon etc. These industries requires substantially large amount of process water. This could be met by reusing water as for as possible. Evaporation and crystallization are the most preferred techniques for separation of sodium sulphate but becomes uneconomical when salts concentration is low especially in industrial waste water. In the present work performance of two commercial CSM membranes model NE-1812-70 (nano membrane) and model RE 1812-50 (reverse osmosis membrane) were evaluated for concentrating the waste water stream to recover water and sodium sulphate for reuse. The results show that NE-1812-70 membrane gives higher water recovery compared to RE 1812-50 at same conditions. Also it was found that by using NE-1812-70 membrane waste aqueous stream could be concentrated up to 14.1% compared to 9.29% by RE 1812-50 at pressure of 25bar.