Reverse Osmosis (RO)

By applying pressure, water is forced through a semi-permeable membrane and dissolved salts, minerals, organic matter and microorganisms are rejected.

This technology was developed for NASA's space programs in the 1960s and has become one of the most effective water treatment methods today. In normal osmosis, low concentration solution passes through semi-permeable membrane to high concentration solution. In RO, this process is reversed by applying high pressure (10-80 bar).

Only water molecules pass through membrane, everything else is rejected and discharged as concentrated wastewater. RO membranes have pore sizes of 0.0001 micron (1 Angstrom) and are made from Thin Film Composite (TFC) or Cellulose Acetate (CA) materials. These membranes are used in spiral wound or hollow fiber configuration and remove 95-99% of dissolved salts, 99%+ of organic matter, and 99.99%+ of bacteria and viruses. Pre-treatment is critical for successful operation of RO systems.

SDI (Silt Density Index) should be below 5, chlorine removal should be done, antiscalant dosing should be applied and pH should be kept between 6-7. When these conditions are met, membrane life can be 3-7 years.