“What quality of water should I use?” The answer depends on the application.
Water is the fluid most often used in cleaning, whether it is for personal, household, industrial, or the manufacture of high-value product. Water
is the most abundant cleaning chemical. With appropriate additives, water-based cleaning has proven successful. However, particularly in critical manufacturing, the wrong water quality can derail
the process and undermine product quality. How do you get water
to the right quality? Why might you have to treat water?
BFK Solutions LLC
Pacific Palisades, Calif.
Not all water is the same
There is no “pure” water. Naturally occurring water is not pure,
whether it comes from underground wells, surface reservoirs,
or even freshly fallen rain. This is because water is a very
aggressive solvent and picks up minerals from the ground or
gases from the air.
• Tap water
Tap water is water coming into the facility from the local water
district. It may come directly from a well or reservoir and
generally has been treated so that it is safe to drink or bathe in
and, in many communities, materials such as fluorides have
been added. One of the primary issues with using tap water
for industrial processes is that the consistency varies greatly
from location to location and from season to season.
• Hard water
Water that contains higher levels of dissolved minerals
such as calcium and magnesium is considered to be hard.
Although hard water may taste better due to the included
minerals, it is not as effective for cleaning. Dissolved minerals interfere with the effectiveness of soaps and may remain
as residues when water evaporates or precipitates from the
water to form scale.
Water purification treatments
For personal and household use, many people employ some
degree of water conditioning. However, the quality of water
required for industrial and high precision applications is generally higher. In order to determine the optimal treatment, it is
important to understand both the terminology and the methodology of the various water treatment techniques.
• Soft water
Soft water is not necessarily mineral free. Hard water is
softened by using an ion exchange process. Many water
softeners employ a cation exchange resin where the nega-
tively charged resin beads are bonded to positively charged
sodium cations. Calcium and magnesium cations, being
more strongly bonded to the resins, displace the sodium
and thus are removed from the water. The exiting water
contains lower concentrations of the hard minerals but
now contains sodium. Although sodium interferes less with
soaps and does not precipitate as scale, the water still has
the same ionic content.