Forward osmosis (FO) differs from reverse osmosis in that it doesn't require external pressure to separate fresh water from a feed solution across a semipermeable membrane. After nearly two decades of research, FO is being used in a number of different separations, such as seawater desalination, wastewater reuse, brine concentration in industrial processes, and product concentration in food and beverages. Among these applications, dewatering or product concentration has gathered commercial momentum.
Porifera, a California-based FO startup, was among the first few entrants in the FO space. It offers flat-sheet, plate-and-frame FO modules. These hydrophilic membranes offer a high flux (33 LMH/bar) and salt rejection, lower susceptibility to colloidal fouling, as well as low concentration polarization (CP – a high CP lowers flux and leads to membrane scaling). One of Porifera's target markets is food and beverage separations, i.e., dewatering of products. The company has multiple pilots and customers for dewatering milk, wine, beers, and juices, as well as concentrating wastewater for reuse.