Reverse Osmosis can remove 95-99% of the dissolved salts (ions), particles, colloids, organics, bacteria,and pyrogens from the feed water. An RO membrane rejects contaminants based on their size and charge. Any contaminant that has a molecular weight greater than 200 is likely rejected by a properly running RO system. Likewise, the greater the ionic charge of the contaminant, the more likely it will be unable to pass through the RO membrane. For example, a sodium ion has only one charge (monovalent)
and is not rejected by the RO membrane as well as calcium for example, which has two charges.
Therefore, an RO system does not remove gases such as carbon dioxide (CO2) very well because they are not highly ionized (charged) while in solution and have a very low molecular weight. Because an RO system does not remove gases, the permeate water can have a slightly lower than normal pH level
depending on CO2 levels in the feed water as the CO2 is converted to carbonic acid.
Reverse Osmosis is very effective in treating brackish, surface and ground water for both large and small flows applications. Some examples of industries that use RO water include pharmaceutical, boiler feed water, food and beverage, metal finishing and semiconductor manufacturing to name a few.