Friday, 2 May 2008

Benefits of the Reverse Osmosis Water Filter

Reverse osmosis water filters function by passing water through a membrane-type filter that leaves impurities on the other side. Clean water is deposited in a reservoir, to be pumped up to a separate drinking water faucet, and the contaminants on the other side are flushed out of the system later. This type of water filter is among the best ways to clean your water, and it will remove most contaminants: most bacteria and viruses, pesticides and other VOCs, hydrogen sulfide, nitrates, sediments, arsenic, chlorine, fluoride, heavy metals like lead and mercury, iron, and even bad tastes.

The reverse osmosis water filter is also referred to as a hyperfiltration system. That's because it is so very effective at removing contaminants from your water supply. It works by moving your water through a series of reservoirs, in which the clean water moves to the clean side of the filter, leaving behind the contaminants. The filter does not work through pressure; instead, water must move passively. This means that the filtration process is slower than you might find in other water filtration systems. A reverse osmosis water filtration system will require a large tank to be installed under your counter which will provide a drinking water reservoir. In most systems, you can expect to produce around fifteen gallons a day of bottled-quality water. If you're a bottled water fan, this will save you much more than the reverse osmosis filter will cost you.

There are two types of membranes typical to reverse osmosis water filters. A thin film composite (TFC) membrane is very good at removing contaminants, but it is also very susceptible to damage from chlorinated water supplies. An activated carbon pre-filtration system may need to be installed upstream of your TFC membrane to remove chlorine before it gets to the membrane. The other type of membrane is the cellulose triacetate (CTA) filter, which is also good at removing contaminants though inferior to the TFC, but does not have a problem processing chlorine. Make sure before installing your water filtration system that you have the membrane most appropriate to your water system; a damaged membrane can force you to replace your entire filtration system.

Some water systems have biological contaminants like bacteria or even amoebas and other single-celled organisms. If this sounds like you, you may need an ultraviolet filter as well as a reverse-osmosis filter. The one thing that reverse osmosis water filters are not great at removing is the biological contaminants; they get most of it, but it only takes one getting through to contaminate your whole reservoir. The UV filter will kill all living things in your water, even if they get through, solving your problem. So you may need a three-filter system for the best water: an activated carbon to remove the chlorine and most contaminants, a reverse osmosis filter to remove most other contaminants, and finally a UV filter to destroy any living organisms that still made it through. In return, you'll get the cleanest possible water supply for your family.

The only other thing you may need to be concerned about with a reverse osmosis water filtration system is the amount of water it takes to create those fifteen gallons a day - up to ten gallons for each gallon of clean water created. If you live in an area where water needs to be conserved, you may need to ensure that rejected water goes into your gray water reservoir, where it can be used to feed your flowers.

Trent Barrett is a consultant who writes for You can visit their homepage to learn more about Home Water Purifiers.

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