Exploring the Performance Parameters of a Commercial-Scale Hollow Fibre Forward Osmosis Module during the Arabian Gulf Seawater Desalination

Forward osmosis (FO) is considered an emerging and energy-efficient technology for seawater desalination. Future research should focus on the large-scale exploration of efficient membranes and draw solutions to assess the real feasibility of the technology. This study explores the performance of a commercial-scale cellulose triacetate-based hollow fibre FO membrane in a pilot-scale FO desalination system of 10 m3/d capacity assisted by a polyelectrolyte draw solution. The large-scale membrane was divided into ten equivalent portions to evaluate the performance of the FO membrane more effectively. The study revealed that maximum water recovery was achieved at the centre and least towards the axial directions of the module, influenced by draw solution (DS) concentration distribution. Higher flow rates of both feed solution (FS) and DS have a higher potential to extract product water throughout the membrane configuration due to the reduced concentration polarization effect and the enhanced mass transfer coefficient. The stable performance of the FO membrane was verified over the long run to produce freshwater with high rejection towards toxic boron. An optimized overall water recovery of 40.0% was achieved with a permeate flow of 6.0 L/min by maintaining FS and DS flow rates of 15.0 L/min and 20 L/min, respectively. The FO system has low capital cost consumption considering the less energy of 0.15 kW/m3 consumed by the system; however, integration of the system with a low-energy DS recovery system will effectively reduce the overall energy cost of the system.