Water Treatment Technologies
Different Treatment for
No single water treatment technology is effective
in treating all water problems, which can range from scale-depositing hard
water to disease-causing organisms like Cryptosporidium. Specific
technologies are applied to meet specific needs, either individually or
in combination. Equipment using the various water treatment technologies
is applied at the point-of-use (POU), such as the kitchen sink where water
is actually drawn for drinking or cooking; or at the point-of-entry (POE),
where water enters a home or business.
In a conventional filtration system, water
passes through a filter media, such as a solid block carbon filter (usually
a cartridge in smaller units) , which either adsorbs or physically screens
out various contaminants.
Reverse Osmosis (RO)
Reverse osmosis systems pass water through
a synthetic, semipermeable membrane that rejects most contaminants. Virtually
all RO units have carbon pre- and/or post-filters to provide additional
treatment for health-related contaminants.
Distillers heat water in one chamber and
turn it into steam. The steam then passes from one chamber to another,
where it is condensed back into water. More than 99 percent of aesthetic-
and health-related contaminants, such as lead, some heavy metals, bacteria
and cysts remain in the heating chamber.
Water softeners use the "ion exchange" principle
to exchange ions of either sodium or potassium for ions of hardness minerals
(calcium and magnesium) present in the source water. Some health-related
contaminants also can be treated, such as radium and low levels of lead.
An offshoot of this technology using "anion exchange" reduces arsenic,
nitrates, and mercury.
Oxidizing chemicals like chlorine, bromine,
and ozone are added to water through a feed system that controls concentration
and allows appropriate contact time. These chemicals neutralize aesthetic
organic contaminants in the water and also kill a variety of biological
Ultraviolet (UV) systems use ultraviolet
light to eliminate various biological pathogens.
Aerators temporarily store source water in
a tank to allow easily evaporated volatile contaminants to be vented off.
Air can be bubbled through the water to speed the evaporation process.
The performance of equipment can vary, so
it is important to look for products tested and proven to be successful
for the specific contaminant(s) to be treated.