Nanofiltration is a membrane liquid separation technology located between reverse osmosis and ultrafiltration. Reverse osmosis can remove the smallest solute with a molecular weight of less than 0.0001 micron, and nanofiltration can remove solutes with a molecular weight of about 0.001 micron. Nanofiltration is essentially a low-pressure reverse osmosis, which is used in occasions where the purity of the water produced after treatment is not particularly strict. Nanofiltration is suitable for treating well water and surface water. Nanofiltration is suitable for water treatment systems that do not need a high desalination rate like reverse osmosis, but it has a high ability to remove hardness components, sometimes called "softening membrane". The operating pressure of the nanofiltration system is low and the energy consumption is lower than Corresponding reverse osmosis system.
