application and optimization in chromium-contaminated wastewater treatment of the reverse osmosis technology

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.