Reverse Osmosis (RO) is a modern process technology to purify water for a wide range of applications, including semiconductors, fisheries, food processing, biotechnology, pharmaceuticals, power generation, seawater desalting, and municipal drinking water.

Reverse Osmosis is the cost effective water purification system it is an immediate source of pure water. The process of reverse osmosis (RO) represents the finest level of liquid filtration available today. And though the term sounds mysterious, reverse osmosis isn’t really that complicated.

Ordinary water filters use a screen to separate particles from water streams. The holes that these Filters have are fairly large. This allows just about everything that is dissolved in the water to pass through as well. An RO system employs a semi-permeable membrane. The membrane is a thin, multi-layered sheet with pores so small that water molecules can pass through, but it acts as a barrier to dissolved solids like salts and other chemicals. Thus even Bacteria and viruses are trapped and not allowed to pass through.

Maximum purity is attained by reducing

  • 95% – 99% of the TDS
  • 99% of the organics (including pyrogens) and bacteria

Reverse Osmosis systems remove salts, micro-organisms and high molecular weight organics. The System capacity depends on three major factors.

    • The feed water temperature
    • Total Dissolved Solids in feed water ( TDS )
    • Operating pressure and the over all recovery of the system.

For waters with Total Dissolved Solids of 200 ppm or more, Reverse Osmosis is less expensive than Ion Exchange. Even on comparable water it has better sediment and organic removal capabilities. Compared with Distillation, Reverse Osmosis uses only a fraction of the total energy and does not have high temperature problems, scaling and corrosion.

Compared with other conventional water treatment processes, Reverse Osmosis has proven to be the most efficient means of removing salts, chemical contaminants and heavy metals, such as lead, from drinking water.

A simple illustration to show how RO works to purify water is provided.

Reverse Osmosis is a membrane separation process in which feed water flows along the membrane surface under pressure. Purified water permeates the membrane and is collected, while the concentrated water, containing dissolved and undissolved material that does not flow through the membrane, is discharged to the drain.


With cross-flow filtration, the feed stream continuously flows across the membrane; anything that does not go through the membrane gets carried off with the cross-flow and is sent to the reject port. In this way the “Reverse Osmosis” process can continue non-stop without clogging the membrane.

Reverse osmosis can treat a wide variety of health and aesthetic contaminants that cause unpleasant taste, color, and odor problems like a salty or soda taste caused by chlorides or sulfates. RO can also be effective for treating health contaminants like arsenic, herbicides/pesticides, lead, mercury, nitrate, and radium.