The content of sulphate, chloride, and fluoride in drinking water can be reduced by nanofiltration. The method is partial softening without the use of regeneration chemicals.
Nanofiltration is applied to purposively reduce unwanted components in full or in part. Nanofiltration applies a pressure typically under seven bar, resulting in lower energy consumption.
Nanofiltration is a membrane technology, which in its mode of operation and construction is very similar to reverse osmosis. A nanofiltration membrane primarily restrains divalent ions and larger molecules. When it comes to the filtration process, a nanofiltration unit is placed between reverse osmosis and ultrafiltration – see the diagram.
Click on the diagram for large version. A nanofiltration unit is placed between reverse osmosis and ultrafiltration.