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Distilled Water
About Distillation Water
Treatment Systems
Distillation is a process of
separating substances from a liquid. It involves changing the liquid state to
the gas state by boiling the water. Water distillers use heat to boil water
into steam which is condensed back into water and collected in a purer form.
When water boils, it leaves impurities behind in the boiling chamber. The
rising steam passes into a cooling section and condenses back into a liquid.
The condensed liquid (water) then flows into a storage container. Distillers
remove almost all of the impurities from water supplies. Distillers are
commonly used for removing nitrate, bacteria, sodium, hardness, dissolved
solids, most organic compounds, heavy metals, and radionucleotides from water.
Distillers remove about 99.5 percent of the impurities from the original
water. They produce sodium free water, and are relatively easy to maintain and
most distillers are mechanically simple.
Removal of volatile
organic compounds (VOC)
Distillers can remove VOCs
by three methods: 1) gas vents, 2) fractional columns and 3) activated carbon
filters (ACF). Distillers that use a combination of VOC removal methods are
more efficient than one single method. Gas vents are small holes drilled into
the passage leading to the cooling coils. Gas vents allow VOCs to escape the
distiller before they enter the cooling section coils. These holes (one or
two) are usually from .045 inches to .065 inches in diameter. Activated carbon
filters (ACF) trap VOCs (refer to Activated Carbon Filtration in the Water
Treatment Systems for Household Water Supplies Series). The ACF units are
normally located at the end of the cooling coils and remove the VOCs prior to
entering the distilled water storage container. Removal of VOCs in distillers
without gas vents, fractional columns or ACFs can also be accomplished with
some success by discarding the first pint (1/2 liter) of distilled water in
the storage container. Heat generated by a distiller must be dissipated into
the surrounding environment. Distilled water has a bland taste, because the
dissolved minerals that give water a pleasing taste have been removed.
Distilled water should be stored under sanitary conditions in plastic, glass
or stainless steel containers.
Household distillers are designed for
providing water for drinking and cooking. It is not economical to distill
water for other uses like flushing toilets, bathing, washing clothes, and
cleaning.
Proper Maintenance
As
water is heated the impurities in the boiling chamber increase in
concentration. The water left behind in the boiling chamber is discarded and
the process is started over. Distillers can allow 0.3 to 0.5 percent of water
impurities to exist in the storage container after distilling. Some volatile
organic contaminants (VOCs), certain pesticides and volatile solvents, boil at
temperatures very close to water (207-218 degrees Fahrenheit). These types of
contaminants will not be substantially reduced in concentration by
distillation. Properly equipped distillers can reduce VOC concentrations
effectively. Although bacteria are removed by distillation, they may
re-colonize on the cooling coils during inactive periods. Minerals and other
residues accumulate in the boiling chamber as water is boiled away. These
minerals and compounds need to be removed occasionally. The boiling chamber of
a distiller should be emptied about once a week. When distillation is
continuous, the boiling chamber should be emptied more often. If these
materials (scale and sediment) are not removed periodically, a distiller
becomes inefficient. The residue from the contaminants that were separated
from the water can create a slight odor. However, you are no longer ingesting
it in your tap water. Mineral scale buildup from hard water can be difficult
to remove without the use of an acid-type cleaner. Commercial cleaning agents
are available. The cleaners usually contain sulfamic acid or other organic
acids. DO NOT use strong mineral acids like hydrochloric, sulfuric or nitric
acids to clean distillers. Strong acids can damage stainless steel and
aluminum. Follow the manufacturer’s suggested maintenance instructions.
An alternative cleaning agent is
vinegar because it contains acetic acid, a weak organic acid. Pour a 50
percent solution of vinegar into the distiller to about 1/2 inch above the top
of the mineral line. Let the unit sit over night, then discard and rinse. If
mineral scale is still present, increase the vinegar concentration or cleaning
time.
Other regular maintenance duties may
include replacing the ACF cartridge and keeping the gas vent holes free of
mineral deposits. These steps are necessary to ensure that distillation units
equipped to remove VOCs will effectively perform that function.
Lifespan
The lifespan of any
distiller depends on the levels of impurities in the raw water supply, how
often the distiller operates, and how often the distiller is cleaned. A good
distiller will last many years with proper maintenance and routine cleaning.
The most common repair for distillers is replacing a heating element or a
cooling fan.
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