RO MEMBRANE

Reverse Osmosis is a process in which dissolved inorganic solids (such as salts) are removed from a solution (such as water). This is accomplished by household water pressure pushing the tap water through a semipermeable membrane.

Reverse Osmosis is a technology that is used to remove a large majority of contaminants from water by pushing the water under pressure through a semi-permeable membrane.

To understand the purpose and process of Reverse Osmosis you must first understand the naturally occurring process of Osmosis.

Osmosis is a naturally occurring phenomenon and one of the most important processes in nature. It is a process where a weaker saline solution will tend to migrate to a strong saline solution. Examples of osmosis are when plant roots absorb water from the soil and our kidneys absorb water from our blood.

Below is a diagram which shows how osmosis works. A solution that is less concentrated will have a natural tendency to migrate to a solution with a higher concentration. For example, if you had a container full of water with a low salt concentration and another container full of water with a high salt concentration and they were separated by a semi-permeable membrane, then the water with the lower salt concentration would begin to migrate towards the water container with the higher salt concentration.

Reverse Osmosis Systems (RO): Water pressure is used to force water molecules through a very fine membrane leaving the contaminants behind. Purified water is collected from the “clean” or “permeate” side of the membrane, and water containing the concentrated contaminants is flushed down the drain from the “contaminated” or “concentrate” side. The average RO system is a unit consisting of a sediment/chlorine pre filter, the reverse-osmosis membrane, a storage tank, and an activated-carbon post filter.

Reverse osmosis removes salt and most other inorganic material present in the water, and for that reason, RO lends itself to use in places where the drinking water is brackish (salty), contains nitrates or other dissolved minerals which are difficult to remove by other methods.

Stages of Filtration

The modern RO system is a unit consisting of a sediment pre-filter to remove particulates, turbidity, sand and rust; an activated carbon pre-filter to remove the chlorine, pesticides, herbicides, disinfectants, and VOCs which might otherwise damage the reverse osmosis membrane; the reverse-osmosis membrane which removes virtually everything such as heavy metals, lead, salt, chromium and dissolved solids; a storage tank, and an activated-carbon post filter. The carbon post filter or polishing filter is necessitated by the demineralized, slightly acidic RO water attacking the rubber inside the storage tank, dissolving some of the rubber. This can be avoided by remineralizing the water prior to storage. This remineralization technology is found in the patented Artesian Full Contact system.

Sediment Stage: removes rough particles, sand and rust.

Carbon stage: removes chlorine and chemicals which would otherwise damage the TFC reverse osmosis membrane. Multiple carbon stages my be necessary at this point depending on the carbon quality and contact time.

Reverse osmosis stage: removes dissolved solids nd virtually everything larger than the water molecule itself. This is where the bulk of the purification is accomplished.

Remineralization Stage: water purified by reverse osmosis is highly pure and slightly acidic. The Tap Master Artesian Full Contact remineralizes with calcium and magnesium to balance the pH, improve the taste and introduce healthy minerals. Learn more about Alkaline Water.

Storage tank

Optional or application specific water treatment stage(s): UV filter to destroy microorganisms, nitrate/arsenic/fluoride/deionization selective filters to remove whatever small amount remains of these contaminants.

Final Carbon stage: also known as a “polishing” filter this carbon filter removes any tastes or odors the acidic RO water has “picked up” from the storage tank. In other words the acidic water produced from systems without the Artesian Full Contact technology will dissolve some of the rubber in the storage tank which the final carbon filter then removes.

Membrane filtration can be a very efficient and economical way of separating components that are suspended or dissolved in a liquid. The membrane is a physical barrier that allows certain compounds to pass through, depending on their physical and/or chemical properties. Membranes commonly consist of a porous support layer with a thin dense layer on top that forms the actual membrane. Types of Membrane filtration based on membrane pore sizes are described below;