Brackish water desalination became viable in the early 1950's when GE Water & Process Technologies developed the world's first commercially-applied membrane desalination technology. This breakthrough, called electrodialysis (ED), is an electrochemical separation process in which ions are transferred through ion exchange membranes by means of direct current (DC) voltage. In the ED process, ions are removed from the feed water as the current drives the ions through the membranes to desalinate the process stream. In the early 1970's, ED was updated to electrodialysis reversal (EDR), which provided reversal of the electric field and automatic membrane cleaning. Today, EDR is widely used to economically treat water supplies which are challenging for other technologies to process and where water recovery up to 95% is required. The ability to remove minerals and salts provides a solution to convert previously unusable waters to high purity resources for drinking water or high purity industrial uses.