Nanofiltration

1) uses less power 2) saves on corrosion 3) works with a selective semi permeable membrane 4) pressure driven membrane separation process

One of the newest and most leading edge technologies in water treatment is now available for practical use in your home, business or manufacturing facility.

Nanofiltration is a pressure driven membrane separation process. The filtration process takes place by forcing water under pressure through a selective semi permeable membrane. The driving force of the separation process is the pressure difference between the feed water and the filtrate (permeate) sides of the membrane, which is identical to the reverse osmosis process.

However, because of the chemistry of the rejection surface of the membrane, it selectively removes ions that have a valence (charge) of two or more both positive and negative. Ions with a valence of one (monovalent) are reduced but not to the levels achieved by a reverse osmosis membrane. For these reasons, the product water is virtually void of hardness but remaining salt is in the range of 25%.

Nanofiltration is favored where hardness is objectionable but small amounts of salt is acceptable because required operating pressures are lower (less power consumption) and recovery is higher (less wasted water). The established application rules for reverse osmosis membranes apply to Nano membranes vis-a-vis pre-treatment, recirculation rates, chlorine tolerance, operating temperatures, silt density index, etc. The Nano process is often referred to as a softening process which is true, but long membrane life is based on following the application rules.

The one misconception that people have is that it does not require pre-treatment, and that's simply not true; you have to pre-treat the water going through nanofiltration as well as water pre-treatment going through a reverse osmosis system.