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 water produced. You will also acquire the information you need to choose the best drinking water filter system for your family.
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) 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) The yield rate of these systems is around one gallon of filtered water per hour. So, if you want to take a shower, you will need to invest in a special storage tank to hold the water under pressure.
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.
RO reviews list maintenance as one of the biggest issues, followed by overall costs. Cost to produce a gallon of filtered water is between 18 cents to 24 cents.
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.
With D systems, water flows over a heated surface, turns into a vapor that is sent to a cooling chamber where it condenses back into a liquid. Inorganic compounds such as minerals like lead, magnesium, calcium, etc. are removed in this process.
Distillation also destroys and bacteria present. Chlorine-resistant 'bugs' like Cryptosporidium and Giardia, are also removed at this point.
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.
In the earlier versions of these filters, the water was filtered by simply forcing it through a cylinder containing granular activated charcoal (GAC). The activated charcoal was used since it was recognized by the U.S. EPA as the best filtering medium for removing chlorine, volatile organic chemicals (VOCs) and synthetic organic chemicals (SOCs).
However, these first systems:
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.
No more problems. The cysts could not get pass the tiny, submicron pores and the water could not avoid being filtered through the solid block.
And, of course, the activated charcoal removes the chemicals like drugs, VOCs, SOCs, etc.
And, what does the chemically charged resin do?
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.
Just remember, whatever water filter you use, don't let it be 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) 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) The yield rate of these systems is around one gallon of filtered water per hour. So, if you want to take a shower, you will need to invest in a special storage tank to hold the water under pressure.
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.
RO reviews list maintenance as one of the biggest issues, followed by overall costs. Cost to produce a gallon of filtered water is between 18 cents to 24 cents.
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.
With D systems, water flows over a heated surface, turns into a vapor that is sent to a cooling chamber where it condenses back into a liquid. Inorganic compounds such as minerals like lead, magnesium, calcium, etc. are removed in this process.
Distillation also destroys and bacteria present. Chlorine-resistant 'bugs' like Cryptosporidium and Giardia, are also removed at this point.
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.
In the earlier versions of these filters, the water was filtered by simply forcing it through a cylinder containing granular activated charcoal (GAC). The activated charcoal was used since it was recognized by the U.S. EPA as the best filtering medium for removing chlorine, volatile organic chemicals (VOCs) and synthetic organic chemicals (SOCs).
However, these first systems:
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.
No more problems. The cysts could not get pass the tiny, submicron pores and the water could not avoid being filtered through the solid block.
And, of course, the activated charcoal removes the chemicals like drugs, VOCs, SOCs, etc.
And, what does the chemically charged resin do?
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.
Just remember, whatever water filter you use, don't let it be your body.
About the Author:
David Eastham has done extensive research on such subjects as reverse osmosis to find the best way to provide good, clean drinking water. Follow him for his picks as the best dollar for dollar buys, and the best products overall, in water filtration technology.
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