Osmotic energy recovery from Reverse Osmosis using two-stage Pressure Retarded Osmosis.

Abstract

The integration of Pressure Retarded Osmosis (PRO) with Seawater Reverse Osmosis (SWRO) is studied here, concentrating on the effect on the overall energy consumption and on the effluents. For this, two alternative designs are evaluated: a previously studied one-stage PRO (SWRO-1PRO) and a newly proposed two-stage PRO (SWRO-2PRO). The analysis results obtained from extrapolation of laboratory data using models show better performance for SWRO-2PRO (without using external impaired low-salinity water flows). The improvement of performance thanks to PRO increases with the increase of the feed concentration and flow.