Nima Asadi - Department of mechanical engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Hamid Soleimanimehr - Department of mechanical engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Ali Alinia-ziazi - Department of mechanical engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.

Although during the last two decades many studies have proved the effectiveness of the reverse osmosis system and this system has been used as a suitable and efficient method to treat drinking and industrial water and to desalinate the seawater, salt water, as well as sewage, it has some shortcomings, including sensitivity to ions, microorganisms, and organic matter in feed water causing problems such as scaling, fouling, as well as biofouling. Acidification of the permeate and its low pH are also other drawbacks of this system. This study is designed based on a two-pass reverse osmosis system, and each pass includes two stages (to provide higher system recovery). Moreover, ion exchange resin and AMBERPACK tank are used as pre-treatments considering the common problems of reverse osmosis system. Such fouling has been done to provide the required quality. It should be noted that by using the exchange resin system instead of the acid injection system, the TDS rate changed from ۳.۱۵ to ۱.۲۷ mg/L, which is equivalent to ۵۹.۶۸ % improvement, the LSI parameter, which in previous cases indicated severe fouling, ideally changed to -۱.۳۵ and -۲.۰۱. Also, the working pressure decreased from ۱۳.۷ bar to ۱۲.۵ bar, which indicates an ۸.۷۶ % improvement in working conditions.

Reverse osmosis, Desalination, Ion Exchange, Boiler, Fouling