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Water Filters Methods and Technologies Used To Treat Water

water filtersIt's ironic that many areas of the world face critical shortages of drinking water on a planet whose surface is 3/4 covered with water. Most of the water, of course, is seawater, which is far too saline for human consumption. And of the little "fresh" water that remains, most is trapped in polar ice caps where it is difficult to harness for use by the world's population. Much of the natural supply of potable water that is accessible faces stress from a growing world population, which increases the basic demand for this natural resource, while reducing the supply further through biological and industrial contamination.

Some good news about this problem is that individuals can take control of their own water quality, and treat their water for nearly all biological and chemical contaminants that may be encountered. Available today, both online or offline in various retail stores, are many sorts for water purification units. The Whirlpool Water Filters are known to be used by many consumers in the residential usa market. These technologies also treat for ''aesthetic'' contaminants that cause potable water to have unpleasant tastes, colors, and odors.

There are many effective technologies used to provide water treatment solutions, and no single technology is effective for treating all of the possible contaminants. A specific technology or combination of technologies is usually applied to treat the specific problem at hand.

Activated Carbon (Granular and Solid Block)

Granular activated carbon is a well-established technology for the reduction of a wide range of aesthetic contaminants, and is quite effective in the reduction of some health contaminants such as volatile organic compounds (benzene, trichloroethylene) and other ''petroleum''-based contaminants.

Because of its molecular makeup, activated carbon can adsorb well, meaning that it can take in or collect many organic molecules on its surface. Granular activated carbon filters are typically inexpensive, and maintenance involves replacing two to twelve cartridges a year, depending on the quality of the raw water and the filter media.

Specially designed solid block and precoat activated carbon filters are also available, which are effective at reducing heavy metals such as lead and mercury. Solid block filters with a pore size smaller than 0.2 microns are often effective against biological contaminants as well.

For an overview of what carbon filters will/will not remove from water, Click Here

Activated Alumina

Activated alumina is a filter media made by treating aluminum ore so that it becomes porous and highly adsorptive. Activated alumina will remove a variety of contaminants, including excessive fluoride, arsenic, and selenium. The medium requires periodic cleaning with an appropriate regenerant such as alum or acid in order to remain effective.

Anion and Cation Exchange

Anion exchange and cation exchange use the chemical ion exchange process to exchange anions and cations on a ''resin'' bed for cations and anions of the contaminant that needs to be removed from the water. For example, in cation exchange, a cation of hardness mineral such as calcium is exchanged for two cations of sodium, effectively removing most of the calcium, and softening the water.

The anions or cations on the resin are eventually exhausted, and replaced by the anions or cations of the contaminant being removed. When this occurs, the bed must be backwashed using a concentrated solution of the base cation or anion, which recharges the bed and flushes the built-up contaminant.

Anion exchange typically uses chloride or hydroxide anions, and can be used to treat for mercury, nitrates, arsenic, and various staining agents. Cation exchange typically uses sodium or potassium chloride, and can also treat for some forms of lead and radium. It is also commonly used to soften water.

For an overview on how water softeners work, Click Here

Disinfection Technologies

Disinfection technologies kill or screen-out biological contaminants present in a water supply. Chlorination, microfiltration, ozone, and ultraviolet light are the four major technologies used to disinfect water.


Chlorination adds a concentration of the chemical chlorine or chloramine to the water supply, where the oxidizing ability of this chemical ''burns up'' the organic contaminants in the water. Chlorine can effectively treat biological pathogens like coliform bacteria and legionella, though it is ineffective against hard-shelled cysts like those produced by Cryptosporidium. Chlorination also treats for organically-related taste, color, and odor problems.

Chlorine is typically fed directly into a well, or into a retention tank where concentration and contact time can be controlled. Chlorination is effective for treating pathogens like coliform bacteria and legionella, though it is ineffective against hard-shelled cysts like Cryptosoridium and Giardia lamblia. Other chemicals like bromine and iodine can also be used to disinfect water through much the same process as chlorination, though they are not as frequently used.


Microfiltration uses a filter media with a pore size smaller than 0.2 microns to physically prevent biological contamination from passing through. Ceramic and solid block carbon are commonly used to provide microfiltration. Ceramic filters have an advantage that they can often be cleaned and reused a number of times before they lose effectiveness.

Carbon block media usually has to be disposed of after each use. This media, however, provides additional treatment for a variety of other health and aesthetic contaminants (see activated carbon section, above). Microfiltration is effective for treating the full range of biological contaminants, including hard-shelled cysts like Cryptosporidium.


Ozone treatment has typically been used in large-scale commercial and industrial applications; however, there has been a recent growth in the number of ozone units designed for use in a single home or business application. Ozone treatment oxidizes organic contaminants in much the same way that chlorine does. An ozone generator converts the oxygen found in air to O3, or ozone. As with chlorination, proper concentrations and contact time is essential for disinfection.

Ozone usually requires the use of a retention tank to accomplish this, and can be used to provide partial treatment in pools. Ozone is effective for treating pathogens like coliform bacteria and legionella, but it is not effective against hard-shelled cysts like Cryptosporidium or Giardia lamblia without using high contact times and concentrations.

Ultraviolet Light (UV)

Ultraviolet light has treated water since the beginning of time through natural sunlight. Modern ultraviolet treatment units use a UV bulb in a clear quartz or plexi-glass housing, around which flows the untreated water. The UV light destroys the genetic material of pathogens like coliform bacteria and legionella, which effectively neutralizes them by preventing them from reproducing. UV is not effective for the treatment of hard-shelled cysts like Cryptosporidium and Giardia lamblia.


Distillation produces high quality, treated water by heating the raw water until it turns to steam. The steam travels through a condensation coil, where it is cooled and condensed back into liquid form in a separate section. Typically, the contaminants present when the water is converted to steam remain in the boiler section, with the condensed water in the second section being substantially free of contaminants. Maintenance of a distillation unit usually involves cleaning out the built-up contaminants on the boiler side of the unit.

Distillation typically provides a high degree of effectiveness against a broad range of health contaminants. Distillation is typically not effective for treating contaminants such as benzene and radon, which give off harmful vapors that can move through the system with the steam. The energy requirement of distillation and a relatively long production time typically limits its use to POU drinking water applications in home and commercial markets. Some distillation units are also tested and approved for the reduction of biological pathogens.

For an overview on how water distillers work, Click Here

Reverse Osmosis

Reverse osmosis (RO) is a common treatment technology that produces high quality water. The process works by forcing water under great pressure against a semipermeable membrane, where ion exclusion occurs. With ion exclusion, water molecules form a barrier that allows other water molecules to pass through while excluding most contaminants.

Typical contaminant rejection rates range from 85% to 95%, and a gallon of highly treated water can usually be produced from two to four gallons of raw water, depending on the initial quality of the water. Maintenance involves the replacement of the RO membrane cartridge every two or three years, and the carbon filter cartridges six to twelve times per year.

RO is effective for the reduction of a broad range of health and aesthetic contaminants, though it is typically not used for the reduction of biological pathogens. RO also incorporates an activated carbon filter, which can provide added treatment for the volatile organic compounds (VOCs) not treated by the membrane itself.

For an overview on how Reverse Osmosis Water Filters work, Click Here

With a knowledgeable application of these effective water filters technologies, you can take the quality of your water into your own hands.

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