Reverse osmosis (RO) desalination is a treatment process for production of fresh, low- salinity potable water from saline water source (seawater or brackish water) via membrane separation. The mineral/salt content of the water is usually measured by the water quality parameter named total dissolved solids (TDS), concentration of which is expressed in milligrams per liter (mg/L), or parts per thousand (ppt). The World Health Organization and the United Sates Environmental Protection Agency (US EPA) under the Safe Drinking Water Act have established a maximum TDS concentration of 500 mg/L as a potable water standard. This TDS level can be used as a classification limit to define potable (fresh) water.
Typically, water of TDS concentration higher than 500 mg/L and lower or equal to 15,000 mg/L (15 ppt) is classified as brackish. Natural water sources such as sea, bay and ocean waters which have TDS concentration higher than 15,000 mg/L are generally classified as seawater.
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.