In February 2019, New Atlas reported on an MIT process that converts brine from desalination plants into useful chemicals. A nanofiltration step removes unwanted compounds, followed by one or more stages of electrodialysis. The main product is sodium hydroxide (caustic soda), which plants use to adjust the acidity of incoming seawater and prevent membrane fouling. Operators could produce more than they need on site and sell the surplus, along with hydrochloric acid. A trial in a prototype desalination plant was planned as the next step.
The report showed brine being treated as a feedstock rather than waste, one that could cut chemical costs and reduce discharges to the sea. Equipment costs and power demand were still open questions at the time.
Source: New Atlas