Forward osmosis and membrane distillation application for sustainable recovery of water and minerals from hypersaline brines

In two recent studies, membrane distillation (MD) and forward osmosis (FO) were evaluated for their sustainable desalination and feed concentration of hypersaline brines. In the study we investigated and optimized the operation of MD and FO to sustainably concentrate hypersaline brine by sustaining high water flux, high salt rejection, and low scaling of the membranes. MD and FO experiments were performed with a feed stream of high salinity water from the Great Salt Lake (approximately 150,000 mg/L TDS). The systems were operated in a batch mode to closely monitor the performance of the membrane and flux decline as the feed solution became more concentrated. Both MD and FO were able to reject high percentage of inorganic salts and concentrate the feed solution to greater than twice its original concentration while recovering more than 50% of the initial feed volume. Membrane scaling mitigation techniques were developed and investigated to restore water flux to its original level and sustain desalination. Novel operating regimes were employed to prevent scale formation on the membrane surface, subsequently sustaining water flux and membrane integrity, and eliminating chemical consumption used in membrane cleaning.