Optimization of recovery rate is critical for desalination processes. A high recovery rate gives a high process yield, but requires higher average concentrate salinities in the membrane elements, higher osmotic pressures and higher membrane feed pressures. In addition, supersaturation of the concentrate results in more scaling, and high membrane flux leads to increased fouling. On the other hand, low recovery rate operation directly reduces process yield and can result in excess pretreatment and supply-pumping expenses. Permeate recovery rate optimization, therefore, is a critical exercise for RO process design and operation.