Toward scale-up of seawater reverse osmosis (SWRO) - pressure retarded osmosis (PRO) hybrid system: A case study of a 240 m3/day pilot plant

Pressure retarded osmosis (PRO) has been considered as a potential technique to harvest salinity gradient energy (or osmotic energy). The SWRO-PRO hybrid system is one of the viable ways of implementing PRO technology to resolve problems associated with seawater desalination. However, relatively few works have been attempted in pilot scales, which are inevitable for the scale-up and practical application of the SWRO-PRO technology. In this context, this paper reports the pilot study results of SWRO-PRO hybrid system (240 m(3)/day). To examine the long-term performance, the plant was operated for more than 2 years. The flux and energy consumption in the plant were analyzed to examine the potential of PRO as a secondary energy recovery device. The fouling propensity of the PRO membranes was examined. Results showed that the use of PRO can reduce the energy consumption of SWRO process by approximately 20%. Moreover, the SWRO brine was diluted up to 63%. This work will provide an insight into the researchers and scientific community by filling the gap between the bench-scale works and the commercial-scale application.