Wednesday, April 29, 2009

The Skinny on Home Water Filters

Being somewhat of an expert, I get a lot of questions about home water filters. Recently, this question showed up in my in-box. Carla asked, "How do water filters work?"

On the surface, it seemed like a simple question to answer, but as I began to write an explanation, I realized that it depends on "which" home water filters we were talking about. Reverse osmosis, submicron filtration, granular carbon, multi-media blocks or ion exchange are all purification methods available for the home and they all work differently.

Let's take a quick look at each of them.

How Do Reverse Osmosis Water Filters Work?

Home water filters that include a reverse osmosis step work by forcing the liquid through a semi-permeable membrane. Only things that are smaller than the pores of the membrane will pass through. Larger contaminants will be blocked. It's a kind of like a pasta strainer.

How Do Water Filters Work that Include Submicron Filtration?

Submicron filtration is similar to, but less expensive than, reverse osmosis. Again, it works like a strainer, allowing only particles smaller than the pores of the filter to pass through. If the porous structure is less than one micron and made of a tough material, anything larger than a speck of dust will be removed.

What About Granular Carbon?

Granular carbon works to remove chemicals because of a process called "absorption." Certain chemicals "stick" to certain materials. Chlorine, for example, "sticks" to granular carbon. If the granules are tightly packed, chlorine can be reduced by more than 99.99% with this method.

What's a Multi-media Block?

Typically, a multi-media block is composed of carbon and other materials that attract different chemicals. With this kind of system, chemicals that are normally difficult to remove, such as THMs, VOCs, MTBE, as well as traces of bug killer and weed killer will be trapped. It's an important step to include, because many of those chemicals increase the risk of cancer or cause other health problems.

How Do Water Filters Work that Include an Ion Exchange Step?

Home water filters that include ion exchange are some of the most technologically advanced systems on the market. They are so advanced that they are difficult to explain in simple terms. Basically, microscopic metallic particles, such as traces of the heavy metal lead, have a slight electrical charge.

They can be trapped in a polymer bed that has the opposite charge, similar to the way that positive and negative magnets stick to each other. This step will reduce the lead content of your water by more than 99%.

How Do Water Filters Work that Include a Number of These Steps?

Well, reverse osmosis is unnecessary, but anyone serviced by a public facility needs all of the other steps, in order to be safe. Home water filters that include all of those steps are reasonably priced. You just have to do a little comparative shopping to get the best deal. Hopefully, Carla, that answered your questions.

Bob Goodhand is an advocate for home and personal water purification systems to protect and promote healthy living. Visit his site at http://natural-purified-water.com/ to discover the drinking water filters that Bob recommends.

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