Application and Optimization in Chromium-Contaminated Wastewater Treatment of the Reverse Osmosis Technology

Abstract

Background: Chromium (Cr) is the most important element used to plate other metals and electroplating factories are still consid­ered to be the most important industries which pollute the environment to this metal. This paper describes a study con­ducted to determine the efficiency of reverse-osmosis (RO) as a membrane technique for removal of Cr from wastewater sam­ples synthetically prepared to be similar to electroplating effluents.
Methods: The RO unit used in this study was a spiral wound module of 2521 TE made by a Korean CSM company. Syn­thetic wastewater samples containing Cr ions at various concentrations of 1 to 20 mg/L were prepared and subjected to treat­ment by RO, and quantitative analysis had been accomplished by a colorimetric method. Evaluation of optimized condi­tions of treatment had also been carried out by determining the effects of changing operating pressure, temperature and pH_S of samples.
Results: Optimum conditions of Cr-treatment by RO in 10 g/L initial Cr concentration were determined to be in the pH range of 6 to 7 and in temperature of about 25ºC at an applied pressure of 200 psi.
Conclusion: Considering the efficiency of Cr removal which was as high as 99% at the optimized conditions it could be con­cluded that RO membrane process may be selected and developed as an effective alternative for treatment of metal-contami­nated effluents of electroplating and similar industries.