Thursday, April 2, 2009

Are Charcoal Water Filters Any Good?

By Peter Abertoning

Many people are becoming aware of the fact that there are contaminants in our drinking water that we ought not be drinking. If this is you and you've been spending some time researching water purification you might have come across charcoal water filters or activated carbon water filters or carbon water filters. But what are they?

Charcoal water filters are filters that use charcoal to remove the contaminants in water during the filtration process. Charcoal is carbon that is created by heating organic matter in the absense of oxygen to high temperature. Commonly coconut husks are used for the organic material.

Charcoal has various properties, primarily that it is extremely porous and this is what is necessary for successful water filtration. These pores allow water, and contaminants, to pass through and for the contaminants to be absorbed by the carbon by means of chemical attraction, because many carbon based or organic compounds are chemically attracted to carbon.

What then, is activated carbon? Activated carbon is charcoal that has been treated with oxygen in the manufacturing process to result in a much higher percentage of pores. In other words it is more porous than ordinary charcoal. The best charcoal water filters use activated carbon.

In fact it is so porous that it can have anywhere up to 20000 or more square yards of surface area for each ounce of carbon. Now that's really porous.

And as a carbon filter absorbs the contaminants and holds them in the carbon material they gradually fill up and need to be replaced.

An activated carbon water filter works well filtering a wide range of contaminants, but doesn't filter all of them, and for this reason the best water filters use a multi stage water filtration process. Not only is the carbon block, or activated carbon filter used but there is a second stage to the process that removes the contaminants that are not removed by activated carbon filtration.

And in the very best water purifiers available there is no reliance on AC filtering only, because very good it is not sufficient on it's own. There is a second stage to the filtering process and this stage is used to filter contaminants that the first stage leaves behind, like nasty lead. And the removal of lead is achieved by an ion exchange process replacing lead ions with harmless potassium ions.

And there are two extremely dangerous potential water contaminants, cryptosporidium and giardia, and these must also be removed by the best filters. This is done by use of an extremely fine filtration process.

There you have the basics of water filtration by use of carbon, or what is known as charcoal water filters, or activated carbon water filters. The activated carbon is not 100% successful in removing all contaminants, but when used in a 2 stage process designed to remove the contaminants that are left behind by the AC filter, it works exceedingly well. You should expect around 99% of lead to be removed, for example.

I spend time discussing the worlds best water filters on my website. - 14130

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