Page 258 - Boiler_Operators_Handbook,_Second_Edition

Chapter 8

Water Treatment

That polarity of the water is what makes it such a
Water is, unquestionably, the most unique sub- good solvent. It has a negative charge on one side and a
stance we will ever encounter. It’s unique character is positive one on the other so it can pull other molecules
important to every form of life on earth. Controlling apart. It pulls molecules of H O apart, converting them
2
-
+
water’s unique characteristics is one of the major occu- to hydrogen ions (H ) and hydroxyl ions (OH ). That’s
pations of the wise boiler operator. how water dissolves itself.
Every solid material dissolved in water is present
as an ion. You’ll note the little plus sign and little minus
WATER TREATMENT sign which indicate that the atoms have something like
an electric charge on them, not unlike the static electric-
There’s more to it than H two O. Perhaps its be- ity charge you build up on a wool suit so everything
cause there are so many water treatment companies and sticks to it. It’s what makes it possible for water to dis-
salesmen that insist their product is the do all and end solve just about anything. In its pure form, where the
all that boiler operators tend to believe they can’t do only ions in water are the hydrogen and hydroxyl ones,
much about water treatment. The fact of the matter is water is hungry. It looks for things to dissolve and will
that nobody can do a better job than a boiler operator dissolve them until it has dissolved enough to satisfy its
that’s been trained. Water treatment isn’t a black art and appetite for ions.
it doesn’t require a college degree to understand it. The Once it has dissolved a fair amount it isn’t as
only problem with it is you can’t see what’s going on in aggressive, that’s why it doesn’t viciously attack the
there and you have to accept certain statements about pipes, hot water heater, and other parts it contacts in
it as fact and base the rest of your decision making on our homes. Everything we do with water treatment is
them. Let’s see if your understanding of water treatment associated with what is dissolved in it, either ions or dif-
isn’t improved in these next few pages. ferent types or gases.
Water is called the “universal solvent” because it One of the critical values in water treatment is
dissolves just about anything. It’s such a great solvent the relative proportion of hydrogen ions in the water.
that it even dissolves itself! I like to think it’s because the Careful experiments have been developed to determine
water molecule is lopsided; it contains two hydrogen at- that there is one hydrogen ion in each million decili-
oms with an atomic weight of one, so they’re very light, ters of pure water. That’s 0.0000001 ions per deciliter.
and one atom of oxygen with an atomic weight of eight; The normal range of hydrogen ion concentrations in
the two hydrogen atoms hang around one side of the water solutions runs from 0.01 ions per deciliter to
much larger oxygen atom. That lopsided condition re- 0.00000000000001 ions per deciliter. Since these numbers
sults in a concentration of protons at the one side, where are a little cumbersome to work with someone decided
the hydrogen is hanging out, and nothing but electrons to measure the hydrogen ion concentration according
at the other side so the molecule of water has a magnetic to the number of decimal places so the range of mea-
polarity. surement is easily described as 2 to 14 (the number of
It’s a reasonable explanation for why a microwave zeros after the decimal place plus one) and the number
oven works. The microwaves are building up and then labeled “pH.”
dumping a magnetic field in the food in the oven several It really does represent the number of hydrogen
times a second and the polarized water molecules keep ions in solution; since it’s the count of decimal places it
twisting back and forth to align with the magnetic field. gets smaller when there are more hydrogen ions. There
Other things, like plastics, don’t have any polarity and are far more hydrogen ions in the solution when the pH
aren’t affected. All those water molecules twisting back is 2 than when the pH is 14. Whenever you deal with
and forth inside the food rubs the other molecules and pH you have to keep in mind that a change in value is a
heats everything up by friction. change in decimal places, not a proportional change. If
243