A steady-state analysis was made for evaluating the RO concentration of sugar solutions assisted by flowing a brine solution in counter-current mode through the permeate side. Calculations show that membrane area requirements for high solute concentrations could be reduced by combining RO with osmotic dehydration. The area requirements are sensitive to salt concentration polarization on the permeate side, particularly when low feed pressures are used. It appears feasible to design membranes/modules with low enough values of permeate side concentration polarization to enable effective feed solution concentration (C) 2000 Elsevier Science B.V. All rights reserved.