Drinking Water Filters - How They Compare in Effectiveness, Required Maintenance, Speed and Cost
In this article, we will look at reverse osmosis, distillation and multi-media block filter systems. You will discover drinking water filters vary widely in effectiveness, required maintenance, speed of filtering, and cost per gallon of filtered water produced. You will also acquire the information you need to choose the best drinking water filter system for your family.
In my opinion, you can pick any of the drinking water filters, outside of your own body, and it is a good one. But some are much better than others.
First, let's look at the reverse osmosis (RO) system.
This system works by forcing water, under pressure, against a semi-permeable membrane which will remove any particles larger than a water molecule. At this stage the RO filter is really just an inefficient, costly pre-filter because:
1. RO systems won't remove chlorine, pesticides or many other toxic synthetic organic chemicals, whose molecular size is smaller than water's so they must be use in conjunction with carbon filters.
2. Even under the required water pressure, two-thirds or more of the water molecules cannot be forced through the membrane and go down the drain as wasted water.
3. RO systems are slow, yielding less than one gallon per hour of filtered water and, consequently, they require a storage tank to give an adequate supply of water.
4. The membrane in the filter will remove metals such as lead, but it also removes minerals our bodies need such as calcium, potassium and magnesium making the water acidic which some health officials consider "unhealthy" water.
The RO system requires considerable maintenance and produces comparatively expensive water at about 18 to 24 cents per gallon.
Next up is the distillation system (D)
Distillation is similar to nature's recycling system. In nature the sun heats the water; it evaporates and rises to the upper atmosphere, condenses in the cooler air and falls as rain.
In the D system, water is passed over a heated coil, the steam rises, goes into a cooling chamber (where the contaminants remain), and condenses back to a liquid.
This system is very effective against bacteria. Any bugs chlorine might have missed such as cysts like Cryptosporidium and Giardia (bad bugs), will be zapped by distillation.
And, yes, the D system will get the lead out, but, like the RO system, it removes the healthful trace minerals as well.
Again, like the RO system, chlorine and other toxic chemicals sneak by because they vaporize at a lower temperature than water, go up into the cooling chamber, condense and return with the water. Also, like the RO systems, D systems must be used in conjunction with a carbon filter.
Distillation, like reverse osmosis, is slow and wasteful, wasting up to 80 percent of the water used. Distillation produces filtered water at a cost of 20 to 26 cents per gallon.
Lastly, let's look at multi-media block filters.
In the earlier version of these filters, water was simply forced through a cylinder filled with granular activated charcoal (GAC), or carbon. Activated charcoal was used because it was recognized by the EPA as the best filtering media for removing chlorine, volatile organic chemicals (VOCs) and synthetic organic chemicals (SOCs).
However, these first systems had a tendency to:
1. Allow some water to flow between the filter's walls and the carbon, so, not all the water was filtered and,
2. There was some concern about these filters not being capable of removing the tiny microbes such as Cryptosporidium and Giardia, or the more difficult to remove chemical compounds.
Both of these issues were resolved with the introduction of multi-media block filter technology.
This technology utilized the advantages of the activated carbon by making it a part of a blended filter media with a sub-micron structure that is extruded or formed into a solid block.
This multi-media block filter system:
1. Removes VOCs and SOCs, which, by the way, make up most of our pharmaceuticals and prescription drugs, herbicides, pesticides, etc. that are increasingly appearing in our water systems, and,
2. Removes the tiny microbes and the more difficult to remove chemical compounds and,
3. The solid block construction prevents the water from channeling around the filter media.
Multi-media block filtration systems have now come to the forefront of drinking water filter technology.
These filters work simply, (no pumps or storage tanks are required). They are efficient, quick and very economical, producing a steady supply of good, safe water for less than 10 cents a gallon.
In my opinion, they are by far the best choice of the home drinking water filters.
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