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Water Purification Technologies
WaterFilter.com
There are many methods used to remove impurities
and contaminants from water.
Each of the water purification technologies is
best at removing one type of contaminant from water, and may not be effective
at all for others.
Fact: People drawing water
from private wells are responsible for assuring that their water is safe for
consumption.
Fact: The Environmental
Protection Agency only requires testing of municipal water sources for about 80
of more than 75,000 known contaminants.
Fact: The standards for safe
drinking water are safe for a 175 pound healthy adult. Those standards
may not be safe for children, pregnant and nursing mothers and adults with
compromised immune systems.
Fact: Municipal water supplies
do not need to test for or eliminate many known contaminants that "do not
present a health threat". These "secondary contaminants" DO make
your water taste and smell bad, corrode your pipes, stain your sinks and tubs -
and may stain your teeth or alter the color of your skin.
Below is a short list of common water
purification technologies and the contaminants that they remove.
Carbon Filtration
Description
Water is passed through activated carbon filter cartridge. Carbon absorbs
objectionable odors, flavors, organic compounds, and many hazardous chemicals.
Carbon absorption is one of the most widely used water filtration systems.
There are two kinds of carbon filter systems - granulated carbon and solid
carbon. A process of heat treating creates "activated" carbon with
microscopic pores and fissures that trap chemical and organic impurities in a
process that mimics the filtering properties of the earth.
The effectiveness of a carbon filter system depends on many factors,
including the type and amount of carbon used, the way the filter is designed
and the length of time that the filter has been in use.
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Removes:
Hydrogen Sulfide, Radon, Chlorine, Volatile Organic Compounds, Pesticides,
Benzene, Colors, Odors.
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Advantages:
Removes dissolved organic compounds and some chemicals effectively. Works
well in conjunction with other filtration systems. Removes objectionable
odors and flavors
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Disadvantages:
Most will not remove heavy metals. Filters must be changed or filtering
capacity will be compromised
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Particulate and Micro Filtration
Description
Micro filtration removes sediments and suspended materials from water by
passing it through a porous filtering material. They do not remove very fine
particles or dissolved substances and are often used before or after other
filtration systems.
There are three types of mechanical microporous filtration systems: depth,
surface and screen filters. Depth filters are often used to pre-treat water
by removing up to 98% of the suspended impurities in water that might foul or
clog other parts of the filter system. Surface filters remove up to 99.9% of
suspended contaminants and may be used as a pre-filter or a final clarifying
filter. Screen filters are placed at the end of the filtration system to
remove the last remaining traces of resin, carbon and microorganisms.
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Removes:
Sediment
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Advantages:
Remove all suspended impurities larger than pore size
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Disadvantages:
Does not remove dissolved particles.....................
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Ultra Filtration
Description
Like Micro-filtration systems, the ultra filtration systems remove impurities
from water by passing it through a "screen". The screen in this
case is a semi-permeable membrane that effectively separates molecules in
water, allowing certain molecules to pass through it while retaining others.
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Removes:
Sediments and extremely fine particles, microorganisms
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Advantages:
Highest quality water for lowest energy investment
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Disadvantages:
May clog. Can be expensive if large amounts of sediment exist. Does not
remove dissolved particles.
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Reverse Osmosis
Description
Reverse osmosis works on the same principle as the body's cells - by
filtering water through a semi-permeable membrane placed between a
concentrated and a dilute solution. The diagram at left should help explain
the process.
The simplest explanation is this:
When two solutions with differing concentrations are separated by a
semi-permeable membrane, the solution with the higher concentration will
infiltrate the solution with the lower concentration. That process may be
reversed by applying pressure of some sort to the side that holds the more
concentrated solution, forcing it through a membrane that will remove the
impurities from the water.
The success of reverse osmosis is dependent on the quality of the permeable
membrane. Those used in RO water filtration systems are capable of trapping
salts, inorganic solutes and many organic compounds.
Reverse osmosis delivers high quality drinking and cooking water, but the
volume of water needed to produce a usable amount makes it impractical to use
for whole-house filtering. It's often combined with other types of water
filtration for a complete water filtration solution.
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Removes:
Lead, Sulfate, Calcium, Magnesium, Sodium, Potassium, Manganese, Aluminum,
Chloride, Nitrate, Fluoride Boron, Most Microorganisms, Organic Chemicals.
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Advantages:
Removes nearly all contaminants of all types to some extent. Requires little
maintenance
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Disadvantages:
Requires large volumes of water - it may take as much as 3 to 5 gallons of
water to recover 1 gallon of usable water. Flow rate is limited to a certain
amount of gallons per day.
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Ion Exchange
Description
Water is percolated through a layer of resin beads that have a sodium
exchange coating. As the water passes through the layer, ions in the water
are exchanged for ions on the beads. The method is often used to
"soften" water before other treatment methods by removing metals
and minerals. It's particularly effective in conjunction with reverse osmosis
and carbon filtration.
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Removes:
Nitrate, Sulfate, Fluoride, Iron, Magnesium, Calcium, Manganese.
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Advantages:
Removes dissolved inorganics (minerals and metals) effectively. Relatively
inexpensive initial cost
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Disadvantages:
Does not effectively remove bacteria. Beads can trap bacteria and become
breeding grounds
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Ultraviolet Radiation
Description
Low level ultraviolet light kills bacterial and viral pathogens. The amount
of radiation produced is negligible, and it leaves no trace.
A typical UV sterilizer looks like a stainless cylinder with water inlet on
one end, and a water outlet on the other. Water passes through a chamber that
has a quartz lamp which performs disinfection.
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Removes:
Bacteria, Viruses
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Advantages:
Sanitizes water
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Disadvantages:
Does not remove suspended particles or ions
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Distillation
Description
Water is heated to boiling, then cooled to condense the water vapor.
Impurities are filtered out by the evaporation, and condensed water is stored
and collected in glass-lined container. Distillation is one of the oldest
methods of removing contaminants from water, but is seldom used for drinking
water, as distilled water has little oxygen and tastes "flat"
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Removes:
Bacteria, Lead, Nitrate, Sodium Chloride, Organic Chemicals, Many Pesticides
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Advantages:
Removes wide range of contaminants. Reusable
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Disadvantages:
Slow process
Requires large amounts of water and energy. May concentrate contaminants with
high boiling points
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As the chart above makes obvious, there is not a
single water purification method that removes ALL contaminants from drinking
and tap water.
Most home purification systems will have a
number of the above methods to filter out all possible contaminants before
delivering fresh, good-tasting, safe water to the tap for cooking and drinking.
WaterFilter.com
Our
company was created with the goal to provide clean drinking water along with
best overall customer experience, and promote healthy lifestyle and clean water
supply. We are happy to offer our customers best water testing and water
purification products on the market at a guaranteed low price.
We are
proud to be partnered with an ISO-9001 certified manufacturer where we have an
ability to custom-build residential and commercial Water Filter Systems for
most water problems.
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