71Hard Water Section
Water contains various amounts of dissolved minerals, some of which impart a quality known as
hardness. Consumers frequently complain about problems attributed to hard water, such as the
formation of scale on cooking utensils and hot water heaters. In this document we will examine the
occurrence, and effects, of hard water and the hard water treatment or softening process that
removes the hardness-causing minerals. The precipitation process most frequently used is
generally known as the lime process or lime soda process. Because of the special facilities required
and the complexity of the process, it is generally applicable only to medium- or large-size water
systems where all treatment can be accomplished at a central location. This process will provide
softened water at the lowest cost. Lime softening can be used for treatment of either groundwater
or surface water sources.
The other commonly used method of softening involves the
ion exchange process. This process has the advantages of a
considerably lower initial cost and ease of use by small
systems or by large systems at multiple locations. The
principal disadvantage is that operating costs are
considerably higher. Ion exchange processes can typically
be used for direct treatment of ground-water, so long as
turbidity and iron levels are not excessive.
For treatment of surface water, the process normally must be
preceded by conventional treatment. Softening can also be
accomplished using membrane technology, electrodialysis,
distillation, and freezing. Of these, membrane methods seem
to have the greatest potential.
Distillers
Various sizes of distillers are available for home use. They all
work on the principle of vaporizing water and then condensing
the vapor. In the process, dissolved solids such as salt, metals, minerals, asbestos fibers, and other
particles are removed. Some organic chemicals are also removed, but those that are more volatile
are often vaporized and condensed with the product water. Distillers are effective in killing all
microorganisms.
The principal problem with a distiller is that a small unit can produce only 2-3 gal (7.5 -11 Lt) a day,
and that the power cost for operation will be substantially higher
than the operating cost of other types of treatment devices.
Water Distillers have a high energy cost (approximately 20-30
cents per gallon). They must be carbon filtered before and/or
after to remove volatile chemicals. It is considered "dead"
water because the process removes all extra oxygen and
energy. It has no taste. It is still second only to reverse
osmosis water for health. Diet should be rich in electrolytes,
as the aggressive nature of distilled water can "leach"
electrolytes from the body.