Science of Water : Concepts and Applications

292 The Science of Water: Concepts and Applications
The signifi cance of this number becomes apparent when you consider that fewer than 25 of the
600+ POTWs in the United States in 1910 were using disinfectants.
CONVENTIONAL WATER TREATMENT
This section focuses on water treatment operations and the various unit processes currently used
to treat raw source water before it is distributed to the user. In addition, the reasons for water treatment
and the basic theories associated with individual treatment unit processes are discussed.
Water treatment systems are installed to remove those materials that cause disease or create nuisances.
At its simplest level, the basic goal of water treatment operations is to protect public health,
with a broader goal to provide potable and palatable water. The bottom line is properly operated
water treatment procedures provide water that is safe to drink and is pleasant in appearance, taste,
and odor.
In this chapter, water treatment is defi ned as any unit process that changes/alters the chemical,
physical, and bacteriological quality of water with the purpose of making it safe for human
consumption and appealing to the customer. Treatment also is used to protect the water distribution
system components from corrosion.
Many water treatment processes are commonly used today. Treatment processes used depend
upon the evaluation of the nature and quality of the particular water to be treated and the desired
quality of the fi nished water.
In water treatment unit processes employed to treat raw water, one thing is certain: as new
USEPA regulations take effect, many more processes will come into use in the attempt to produce
water that complies with all the regulations, despite source water conditions.
Small water systems tend to use a smaller number of the wide array of unit treatment processes
available, in part because they usually rely on groundwater as the source and in part because small
makes many sophisticated processes impractical (i.e., too expensive to install, too expensive to
operate, and too sophisticated for limited operating staff). This section concentrates on those individual
treatment unit processes usually found in conventional water treatment systems, corrosion
control methods, and fl uoridation.
WATERWORKS OPERATORS
Operation of a water treatment system, no matter the size or complexity, requires operators. To perform
their functions at the highest knowledge and experience level possible, operators must understand
the basic concepts and theories behind many complex water treatment concepts and treatment
systems. Under new regulations, waterworks operators must be certifi ed/licensed.
Actual water treatment protocols and procedures are important; however, without proper implementation,
they are nothing more than hollow words occupying space on reams of paper. This is
where the waterworks operator comes in. To successfully treat water requires skill, dedication,
and vigilance. The waterworks operator must not only be highly trained and skilled, but also
conscientious—the ultimate user demands nothing less.
PURPOSE OF WATER TREATMENT
As mentioned, the purpose of water treatment is to condition, modify, or remove undesirable impurities,
to provide water that is safe, palatable, and acceptable to users. While this is the obvious
purpose of treating water, various regulations also require water treatment. Some regulations state
that if the contaminants listed under the various regulations are found in excess of maximum contaminant
levels (MCLs), the water must be treated to reduce the levels. If a well or spring source is
surface-infl uenced, treatment is required, regardless of the actual presence of contamination. Some