Process steps

  1. 1

    Pre-purification

  2. 2

    Microfiltration

  3. 3

    Reverse osmosis

  4. 4

    Ultraviolet light

  5. 5

    Water delivery

Reverse osmosis

Play Reverse Osmosis

Reverse osmosis (RO) membranes are made of a semi-permeable polyamide polymer (plastic). During the RO process, water is forced through the molecular structure of the membranes under high pressure, removing dissolved chemicals, viruses and pharmaceuticals in the water. The end result is near-distilled-quality water so pure that minerals have to be added back in to stabilize the water. RO has been successfully used by the Orange County Water District since the mid-1970s to purify highly-treated wastewater for its seawater intrusion barrier.