Purifying Water via High Water Pressure: How Reverse Osmosis Works

The process of reverse osmosis purification has been used for water since the early 1960’s. Originally reverse osmosis was used for the desalinization of sea water. Now reverse osmosis systems produce a hundred thousand tons of water worldwide every day.

Modern improvements to the systems have made it possible to implement reverse osmosis systems in the home. Water obtained from a reverse osmosis system has a unique degree of purity. This is because of the effective reverse osmosis process.

Osmosis vs. Reverse Osmosis

To understand reverse osmosis, first the general process of osmosis should be clear. Osmosis is the basis of the metabolism of all living organisms. Thanks to it, every living cell receives nutrients and by the same process toxins are removed. Osmosis occurs when two salt solutions of different concentrations are separated by a semipermeable membrane. The membrane allows ions and molecules of a certain size to pass, but acts as a barrier to substances with larger molecules. Therefore, water molecules can penetrate through the membrane, but the molecules of dissolved salts cannot. If the saline solutions on either side of the membrane are of different concentrations then the water molecules of the more concentrated solution will pass through the membrane causing the water level on the other side to rise. Osmosis will occur even if the external pressure of the solutions on each side of the membrane is the same.

Reverse Osmosis

As the title suggests, reverse osmosis is an opposite movement of molecules. If the water molecules in osmosis move from the more concentrated solution to the less concentrated solution then in reverse osmosis the opposite is true. Water molecules will now pass through the reverse osmosis membrane from the less concentrated side into the more concentrated solution. This is the process of reverse osmosis. All reverse osmosis membranes operate on this principal. Reverse osmosis systems separate substances on a molecular level collecting nearly perfectly pure water on one side of the membrane and impurities on the other. Thus, reverse osmosis provides a much higher degree of purification than most traditional filtering methods using mechanical filtration and particle adsorption by means of activated charcoal. Efficient reverse osmosis systems can filter tons of water in a single day, providing potable water to thirsty millions.