PRO and FO coupling with an RD membrane process is proposed to reduce the cost of seawater desalination and the potential for power generation. Three conceptual design configurations, PRO-RU, FO-RO and RU-PRO were evaluated here using standard seawater concentration and impaired water as the draw and the feed solutions respectively. The PRO-R0 and RU-PRO designs were evaluated for power generation and seawater desalination while the P0-RU design was proposed for seawater desalination only. The impact of the draw and feed solutions' flow rate and the impaired water TDS on the performance of each design was estimated using pre-developed software. The simulation results showed that the performance of all designs was more sensitive to the increase in the flow rate of draw solution than to the flow rate of feed solution. Furthermore, all designs showed a decrease in membrane flux and recovery rate with increasing the TDS of feed water from 0.2 g/L to 10 g/L as a result of decreasing the net driving force across the membrane and the concentration polarization phenomenon. The FO-RO design produced the lowest RU permeate concentration followed by the PRO-120 and RU-PRO designs respectively. In terms of power generation, the RU-PRO design was more efficient than the PRO-RO design. The FO-RO design exhibited the lowest desalination power consumption followed by the PRO-RU and RU-PRO designs respectively. At 10 g/L feed concentration, the net power consumption in the FO-RO was 9.4% less than that in the PRO-RO which was in turn 53% less than that in the RU-PRO design. The estimated cost of the FO/PRO module in the PRO-RO design was 2.2 and 43 times higher than that in the FO-RO and RU-PRO designs respectively. Crown Copyright (C) 2014 Published by Elsevier B.V. All rights reserved.