Nanofiltration is based on the same principle as reverse osmosis. The difference: the separation line is slightly lower. Ions solved into the water are less filtered than with reverse osmosis. This saves operation costs.
Typical salt rejection rates are at ca. 80 – 85%. Here, polyvalent ions (e.g. Ca, Mg) are kept back better than univalent (e.g. Na, K) so that Nanofiltration plants are often used as alternative for classic softening.
Where a lower salt rejection is acceptable, Nanofiltration plants constitute cost-effective alternatives to reverse osmosis plants, as Nanofiltration plants can be operated at low pressures. Thus a smaller high pressure pump can be used. Advantage: lower investment costs and above all lower energy costs! Compared to conventional softening, operation costs are considerably reduced as expensive regular regenerations with large salt amounts become completely redundant.
ProMinent offers almost all reverse osmosis plants also as Nanofiltration plants. For details, please contact us. We will be pleased to advise you.