The present study is to analyze and model concentration polarization in spiral wound brackish water membrane elements. The aim of the present work is to study the effect of different operating parameters on the reverse osmosis system which are feed flow rate, feed concentration, and feed temperature on permeate concentration and mass transfer coefficient for the brackish water system. The range of these parameters were; feed concentration (100,200,300,400and500ppm), feed flow rate (0.666, 1, 1.333 and 1.666-2cm3/s), and feed temperature (15, 25 and 35 °C), salts (NaCl, CaCl2 and KCl).Membrane efficiency is effected by the phenomena of concentration polarization (accumulation of solute) and fouling at the membrane surface.Results show that the polymer membrane is very sensitive to changes in the feed temperature. There was up to a 6 % average difference in the permeate concentration between feed temperatures of 15 and 35oC. Doubling of the feed flow rate decreased the permeate concentration by to 13-36 %, but only at a high solute concentration. Membrane parameters were estimated using an analytical osmotic pressure model for high salinity applications. The modeling studies showed that the membrane transport parameters were influenced by the feed salt concentration and temperature.
