RO is a liquid/liquid separation process that uses a reverse semi-permeable membrane. A pressurized feed solution pass over the surface of the membrane, as long as the applied pressure is greater than the osmotic pressure of the feed solution, "pure" water will go from the more concentrated solution to the more dilute side through the membrane to desalt, purify, concentrate and separate the solution, RO membrane has MWCO under 100, which capturing pollutions, like inorganic salt, sugar, amino acid, BOD, COD and so on. At present, RO membrane has applied generally in the water treatment field, such as water desalting, water pollution control, pure water manufacture, waste water treatment.
