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.
Any of these filters are far better than continuing to use your body as a filter, but, depending on your water problems, you will find that some of them are clearly better than others.
Let's start with reverse osmosis (RO) systems since they are the biggest sellers.
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) Chemicals such as pesticides, drugs, chlorine, synthetic organic chemicals, etc. are not removed in the stage of the process since their molecules are smaller than water's. A carbon filter must be used in combination with RO systems to finish the job.
2) Steady pressure is required to force the water molecules thru the membrane and, even then, only about a third of the molecules can be pushed through the filter. The remaining two-thirds is flushed with the filtered contaminants.
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) This stage will get the lead out, but it also removes the minerals our bodies need such as potassium, calcium and magnesium. At that point, the water water has gone from being neutral to being slightly acidic, and some medical professionals believe such water is unsafe to consume on a long-term basis.
The RO systems require considerable maintenance and they produce comparatively expensive water at about 18 to 24 cents per gallon.
Next up is the distillation system (D).
When the sun heats the earth the warm, moist air rises, cools in the upper atmosphere and falls back to earth again as rain or snow. That is a good example of distillation process.
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.
The D systems have the same drawback as the RO systems, however, in that they remove the bad metals like lead but take out the beneficial trace minerals as well.
A wide range of synthetic organic chemicals, drugs, etc. also escape the filtering effects of D systems. Since they vaporize at a lower temperature than water, they remain in the water the whole way. Because of this, just like the RO systems, these units must be used together with carbon filters.
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.
The last systems we will look at are called multi-stage or selective filtration systems.
Activated charcoal or carbon has long been viewed as the best technology for removing chemicals compounds such as chlorine, chlorine byproducts, herbicides, pesticides, drugs, etc., so, the earlier versions of these systems simply ran water through a cylinder filled with a granular form of activated charcoal.
However, these basic designs:
1) Gave water a chance to pass along the walls of the filter and the charcoal so some of the water did not get filtered and,
2) There was a lack of confidence over these filters' ability to stop the extremely small, chlorine-resistant cysts such as Cryptosporidium and Giardia.
A new technology was developed which made the two complaints mute. This new technology kept the filtering power of activated charcoal but changed its form. First, they mixed the activated charcoal with a resin that had been chemically charged and compressed the mix into a solid block composed of 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.
What about the filter resin that covers the adsorption area of the charcoal?
When the resin comes in contact with the water, its chemical make up causes the ions of any heavy metals present in the water, such as lead or sulfur, to break their bonds with the water and jump to the resin like a strong magnet to steel. Lighter metals such as potassium or calcium are not involved in the ion exchange, so, they, the healthy minerals, stay in the water.
When you think of the "Rube Goldberg-ness" of the RO or D systems it is easy to understand why selective filtration technology is leading the industry. Independent laboratory tests have proven the produce the highest quality water and initial costs are more than competitive.
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.
Whatever you do from this point on, please, use some type of filter for your water other than your body.
Any of these filters are far better than continuing to use your body as a filter, but, depending on your water problems, you will find that some of them are clearly better than others.
Let's start with reverse osmosis (RO) systems since they are the biggest sellers.
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) Chemicals such as pesticides, drugs, chlorine, synthetic organic chemicals, etc. are not removed in the stage of the process since their molecules are smaller than water's. A carbon filter must be used in combination with RO systems to finish the job.
2) Steady pressure is required to force the water molecules thru the membrane and, even then, only about a third of the molecules can be pushed through the filter. The remaining two-thirds is flushed with the filtered contaminants.
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) This stage will get the lead out, but it also removes the minerals our bodies need such as potassium, calcium and magnesium. At that point, the water water has gone from being neutral to being slightly acidic, and some medical professionals believe such water is unsafe to consume on a long-term basis.
The RO systems require considerable maintenance and they produce comparatively expensive water at about 18 to 24 cents per gallon.
Next up is the distillation system (D).
When the sun heats the earth the warm, moist air rises, cools in the upper atmosphere and falls back to earth again as rain or snow. That is a good example of distillation process.
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.
The D systems have the same drawback as the RO systems, however, in that they remove the bad metals like lead but take out the beneficial trace minerals as well.
A wide range of synthetic organic chemicals, drugs, etc. also escape the filtering effects of D systems. Since they vaporize at a lower temperature than water, they remain in the water the whole way. Because of this, just like the RO systems, these units must be used together with carbon filters.
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.
The last systems we will look at are called multi-stage or selective filtration systems.
Activated charcoal or carbon has long been viewed as the best technology for removing chemicals compounds such as chlorine, chlorine byproducts, herbicides, pesticides, drugs, etc., so, the earlier versions of these systems simply ran water through a cylinder filled with a granular form of activated charcoal.
However, these basic designs:
1) Gave water a chance to pass along the walls of the filter and the charcoal so some of the water did not get filtered and,
2) There was a lack of confidence over these filters' ability to stop the extremely small, chlorine-resistant cysts such as Cryptosporidium and Giardia.
A new technology was developed which made the two complaints mute. This new technology kept the filtering power of activated charcoal but changed its form. First, they mixed the activated charcoal with a resin that had been chemically charged and compressed the mix into a solid block composed of 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.
What about the filter resin that covers the adsorption area of the charcoal?
When the resin comes in contact with the water, its chemical make up causes the ions of any heavy metals present in the water, such as lead or sulfur, to break their bonds with the water and jump to the resin like a strong magnet to steel. Lighter metals such as potassium or calcium are not involved in the ion exchange, so, they, the healthy minerals, stay in the water.
When you think of the "Rube Goldberg-ness" of the RO or D systems it is easy to understand why selective filtration technology is leading the industry. Independent laboratory tests have proven the produce the highest quality water and initial costs are more than competitive.
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.
Whatever you do from this point on, please, use some type of filter for your water other than your body.
About the Author:
David Eastham has done extensive research on such topics as reverse osmosis to discover the best way to provide good, clean drinking water. Go here now for his selections as the best dollar for dollar buys, and the best products overall, in home water filtration technology.
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