A filtration process that uses membranes to preferentially separate different fluids or ions. Although nanofiltration is not as fine a filtration process as reverse osmosis, it requires the same energy to perform the separation.
A lower pressure membrane treatment technology sometimes used for pretreating reverse osmosis feedwater.
Crossflow membrane separation process for removing particles in the 250 to 1000 molecular weight range, selected salts and most organics. Nanofiltration is often used for water softening and require lower driving pressure than RO.