Membrane filtration is used to remove particles that are too fine for ordinary filtration techniques. It can also be used for concentrating, fractionating, purifying and regenerating liquids, replacing traditional methods of separation by evaporation and centrifugation. For more information, see Section 4.1 of the page New Energy Efficient Technologies That Are Applicable to Manufacturing Processes on the Natural Resources Canada Web site.
Electrodialysis is a technique that consists in extracting sufficiently ionized ions from a solution. It can use less power than electrolysis, but requires a greater surface area and does not concentrate the ions to the same extent.