There are three main water filter systems to consider today, distillation, reverse osmosis and multi-stage or selective filtration. In this article you will see they differ in cost per gallon of water produced, effectiveness, required maintenance and filtering speed. You will also find the information you need to choose a solution for your drinking water problems.
In my opinion, you can pick any of the drinking water filters, outside of your own body, and it is a good one. But, depending on what your water problems are, some of these systems are clearly better.
First let's look at the reverse osmosis (RO) systems.
The main filter in these systems is a semi-permeable membrane about the thickness of a piece of cellophane. Water that has been pre-filtered to remove most of the large particles is forced, under pressure, against the membrane and only particles the size of a water molecule, or smaller, can go thru. For the water conditions most of us have in the US, there is a far better way of doing what this stage does because:
1) RO filters won't remove chlorine, pesticides or many other toxic synthetic organic chemicals because their molecular size is smaller than water's, so reverse osmosis systems must be used in conjunction with carbon filters.
2) RO systems have to be operated under a minimum required pressure to force the water molecules through the filter, and even then, only about one-third of them get through and the rest of the water is wasted.
3) RO systems are slow, yielding less than one gallon per hour of filtered water and, consequently, they also require a storage tank to give an adequate supply of water for bathing.
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 as "unhealthy" water.
The RO systems require considerable maintenance and they produce comparatively expensive water at about 18 to 24 cents per gallon.
Now, distillation systems (D) are next.
We experience distillation every time we shower. Hot, steamy tap water comes out of the shower head and, when the water vapors come into contact with the cool shower surfaces, they condense into droplets.
In the D system, water is passed over a heated coil; the water vaporizes, goes into a cooling chamber and condenses back to a liquid. During this process inorganic compounds like lead, calcium, potassium and other minerals are removed.
All bacteria, even bacteria that are resistant to chlorine such as Cryptosporidium and Giardia will be killed in this stage of the process.
We noted the D systems removes harmful metals like lead, but they also remove the healthful minerals like calcium and potassium just like the RO systems.
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.
Utility bills rise with D systems because they are very wasteful, cleaning only about 20% of the water used. The cost for using D systems to clean up a gallon of water is in the area of 20 cent to 26 cents.
Selective filtration or multi-media block filtration is the last system we will look at.
These systems' first designs simply ran water into a cylinder filled with a granular form of activated charcoal. The activated charcoal has long been recognized as the best filter media for removing chlorine and the rest of the SOCs (synthetic organic chemicals).
But, these simple designs:
1) Allowed some water to flow between the filter's walls and the charcoal, so, not all the water was filtered and,
2) Concern grew over whether or not these filters were able to stop very tiny microbes like Cryptosporidium and Giardia.
Both of these issues were resolved with the introduction of selective filtration utilizing multi-media block filters. This technology utilizes the advantages of the activated carbon by first blending it with a chemically charged filter resin and then extruding, or compressing, it into a solid block containing tiny, submicron pores.
The problems were eliminated since the water could no longer bypass the filter and the cysts were removed by the filter's tiny pores.
And chemical pollutants are obviously filtered out by the activated charcoal.
That leaves the special resin you mentioned...what does it do?
That resin causes any heavy metal ions in the water from metals like lead or mercury to break their bonds with water and snap to this chemically charged surface like a magnet to a piece of metal. However, the lighter minerals, such as calcium and potassium do not join in on the ion exchange, so, bottom line, the good stuff stays in the drinking water.
This selective filtration has now come to the forefront of drinking water filter technology. Not only does it produce the best quality water, but these systems are also the least expensive.
They work simply (no pumps, storage tanks or electricity), efficiently, quickly and very economically, producing a gallon of filtered water for less than 10 cents with virtually no maintenance required.
Just remember, whatever water filter you use, don't let it be your body. - 14915
In my opinion, you can pick any of the drinking water filters, outside of your own body, and it is a good one. But, depending on what your water problems are, some of these systems are clearly better.
First let's look at the reverse osmosis (RO) systems.
The main filter in these systems is a semi-permeable membrane about the thickness of a piece of cellophane. Water that has been pre-filtered to remove most of the large particles is forced, under pressure, against the membrane and only particles the size of a water molecule, or smaller, can go thru. For the water conditions most of us have in the US, there is a far better way of doing what this stage does because:
1) RO filters won't remove chlorine, pesticides or many other toxic synthetic organic chemicals because their molecular size is smaller than water's, so reverse osmosis systems must be used in conjunction with carbon filters.
2) RO systems have to be operated under a minimum required pressure to force the water molecules through the filter, and even then, only about one-third of them get through and the rest of the water is wasted.
3) RO systems are slow, yielding less than one gallon per hour of filtered water and, consequently, they also require a storage tank to give an adequate supply of water for bathing.
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 as "unhealthy" water.
The RO systems require considerable maintenance and they produce comparatively expensive water at about 18 to 24 cents per gallon.
Now, distillation systems (D) are next.
We experience distillation every time we shower. Hot, steamy tap water comes out of the shower head and, when the water vapors come into contact with the cool shower surfaces, they condense into droplets.
In the D system, water is passed over a heated coil; the water vaporizes, goes into a cooling chamber and condenses back to a liquid. During this process inorganic compounds like lead, calcium, potassium and other minerals are removed.
All bacteria, even bacteria that are resistant to chlorine such as Cryptosporidium and Giardia will be killed in this stage of the process.
We noted the D systems removes harmful metals like lead, but they also remove the healthful minerals like calcium and potassium just like the RO systems.
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.
Utility bills rise with D systems because they are very wasteful, cleaning only about 20% of the water used. The cost for using D systems to clean up a gallon of water is in the area of 20 cent to 26 cents.
Selective filtration or multi-media block filtration is the last system we will look at.
These systems' first designs simply ran water into a cylinder filled with a granular form of activated charcoal. The activated charcoal has long been recognized as the best filter media for removing chlorine and the rest of the SOCs (synthetic organic chemicals).
But, these simple designs:
1) Allowed some water to flow between the filter's walls and the charcoal, so, not all the water was filtered and,
2) Concern grew over whether or not these filters were able to stop very tiny microbes like Cryptosporidium and Giardia.
Both of these issues were resolved with the introduction of selective filtration utilizing multi-media block filters. This technology utilizes the advantages of the activated carbon by first blending it with a chemically charged filter resin and then extruding, or compressing, it into a solid block containing tiny, submicron pores.
The problems were eliminated since the water could no longer bypass the filter and the cysts were removed by the filter's tiny pores.
And chemical pollutants are obviously filtered out by the activated charcoal.
That leaves the special resin you mentioned...what does it do?
That resin causes any heavy metal ions in the water from metals like lead or mercury to break their bonds with water and snap to this chemically charged surface like a magnet to a piece of metal. However, the lighter minerals, such as calcium and potassium do not join in on the ion exchange, so, bottom line, the good stuff stays in the drinking water.
This selective filtration has now come to the forefront of drinking water filter technology. Not only does it produce the best quality water, but these systems are also the least expensive.
They work simply (no pumps, storage tanks or electricity), efficiently, quickly and very economically, producing a gallon of filtered water for less than 10 cents with virtually no maintenance required.
Just remember, whatever water filter you use, don't let it be your body. - 14915
About the Author:
David Eastham has done a great deal of research on such topics as reverse osmosis to discover the best way to provide good, clean drinking water. Follow him for his picks as the best dollar for dollar purchases, and the best products overall, in water filtration technology.
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