Indirect desalination of Red Sea water with forward osmosis and low pressure reverse osmosis for water reuse

► A new immersed forward osmosis (FO) membrane cell was designed and tested. ► The FO cell dilutes seawater in cycles by using a wastewater effluent as feed. ► Fouling of the FO membrane will reduce flux by 28% over a period of 10 days. ► Cleaning the FO membrane by air scouring with clean water recovers flux by 98%. ► The system consumes only 50% of the energy used for normal high pressure RO.