The Technology Behind Reverse Osmosis Water Purification Units

Reverse osmosis water purification units use a two step process to purify water. The unit consists of two filters: a pre-filter and a semi permeable membrane. The pre-filter can be either a carbon or sediment filter and removes larger particles from the water before it passes through the semi permeable membrane. The membrane allows water to pass through, but traps pollutants and bacteria in the porous surface. Reverse osmosis is often used in residential filtering.

A reverse osmosis unit needs sufficient water pressure for the process to work. On most models, a pump is used to supply the pressure needed. Most households have sufficient pressure to operate the unit. This method of filtering is so effective, the Center for Disease Control list them as one of the most effective drinking water purification methods.

The semi permeable membrane is self cleaning due to the cross flow process used in reverse osmosis water filter systems. As the water passes through the membrane, wastewater is swept down the drain, taking the impurities and contaminants with it. This keeps the unit’s porous surface of the membrane clear. A significant amount of wastewater is produced during the process, using about five gallons of waste for every gallon these units can purify.

A residential purifier is not difficult to maintain. You will need to occasionally change the pre-filter. How often you will need to change it depends on the filter, size of the unit and amount of water that passes through. Directions included with most reverse osmosis purification units give more specific information about maintenance. The purifier’s semi permeable membrane will need to be changed as well. This occurs less frequently than changing the pre-filter. You will most likely need to replace it a few times each year on most residential units. This is about the only maintenance the system will need. Some models come with warning sounds to alert you if it should stop working for any reason.

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