Man's
very existence depends on water. Water is the major basic commodity
of our lives, it sustains all life and is crucial to our existence.
Roughly 2/3 of our planet is water but less than 1% is drinking
water, found in our freshwater lakes, streams and wells. Nature
has its own method of purifying water called the Hydrologic Cycle,
but "water is best as nature provides it," is a common
misconception. Practically all natural water needs refinement or
treatment to make it safe to drink or more satisfactory to use.
Water
Contaminents
Contaminants
pour into our water resources at a rate of 500,000 tons per day.
The earth's water supply cycle starts in the upper cloud layers.
As it falls to the earth as rain or snow, it picks up impurities
and gases from the atmosphere. Landing on earth, it seeps over
and through the ground, dissolving earth minerals. Passing through
limestone, it dissolves calcium and magnesium, the hardness minerals.
Iron deposits impart iron to the water. Acidity and sediments
are other water issues.
Municipal
water supplies come from surface reservoirs, such as lakes and
rivers, or from underground reservoirs. Usually, municipalities
chlorinate the water to make it safe to drink. Sediment is removed
by filtration. Tastes and odors are reduced or eliminated. The
water is conditioned to comply with certain specifications.
However, hardness minerals, tastes and odors are not always
reduced to the most desirable levels.
Underground
reservoirs provide our private water supplies. Because the water
is raw and untreated, it can have varying amounts of hardness,
iron, tastes, odors, acidity, or combinations of these. Different
localities and water levels affect mineral content.
The
Hydrologic Cycle
The
hydrologic cycle is the earth's natural method of cleansing water.
The earth, sun and atmosphere all work together imitating a distiller.
It is the largest water purification system known to man. In this
cleaning process, surface water evaporates from streams, lakes,
etc. and rises to the sky in the form of vapor. The vapor condenses
into clouds.
When
the condensation in the clouds are heavy enough, it falls to earth
as rain, snow etc. About 70% of the water will evaporate again.
The remaining 30% will replenish surface water. Throughout the hydrologic
cycle, water changes from pure to impure and back to pure again.
Evaporation
Surface water is heated by sunlight and evaporates into vapor
that ascends into the atmosphere. This is the purest naturally
occurring water.
Condensation
When water vapor condenses in the atmosphere, it forms a cloud.
The cloud becomes increasingly 'dirtier' by picking up impurities
- usually in the form of dissolved gases. This atmospheric water
is acidic and aggressive. 'Acidic' water tends to dissolve virtually
all minerals it comes in contact with.
Precipitation
The acidic water returns to earth as precipitation (rain, snow,
sleet, etc.).
Infiltration
The water picks up sediment and dissolved minerals as it seeps
through the soil becoming hard, brackish and contaminated to varying
degrees.
Evaporation
The water eventually heats again and the cycle repeats.