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GUARDING A CITY'S WATER SUPPLY






From: How To Write Special Feature Articles
(Category: PART II)

HOW THE CITY CHEMIST WATCHES FOR THE APPEARANCE OF DEADLY BACILLI; WATER
MADE PURE BY CHEMICALS

BY HENRY J. RICHMOND

"COLON." The city chemist spoke the one significant word as he set down
the test tube into which he had been gazing intently. The next morning
the front page of all the city papers displayed the warning, "Citizens
should boil the drinking water."

Every morning, as the first task of the day, the city chemist uncorks a
curious little crooked tube containing a few spoonsful of very ordinary
bouillon, akin to that which you might grab at the quick lunch, but
which has been treated by the admixture of a chemical. This tube begins
in a bulb which holds the fluid and terminates in an upturned crook
sealed at the end. Into this interesting little piece of apparatus, the
chemist pours a small quantity of the city drinking water, and he then
puts the whole into an incubator where it is kept at a temperature
favorable to the reactions which are expected if the water is
contaminated.

After a sufficient time the tube is inspected. To the untrained eye
nothing appears. The bouillon still remains in the little bulb
apparently unchanged. Its color and clearness have not been affected.
But the chemist notices that it does not stand so high in the closed end
of the tube as it did when placed in the incubator. The observation
seems trivial, but to the man of science it is significant.

What has happened? The water contained some minute organisms which when
acted upon by the chemical in the tube have set up a fermentation.
Gradually, one by one in the little bulb, bubbles of gas have formed and
risen to the surface of the liquid in the closed upper end of the tube.
As this gas was liberated, it took the place of the liquid in the tube,
and the liquid was forced downward until there was quite a large space,
apparently vacant but really filled with gas.

It was this phenomenon that had attracted the attention of the chemist.
What did it mean? It was the evidence that the water which was being
furnished to the city for half a million people to drink contained some
living organism.

Now that, in itself, was enough to make an official of the health
department begin to take an interest. It was not, however, in itself a
danger signal.

Not all bacterial life is a menace to health, the chemist will tell you.
Indeed, humanity has come to live on very peaceable terms with several
thousand varieties of bacteria and to be really at enmity with but a
score or more. Without the beneficent work of a certain class of
bacteria the world would not be habitable. This comes about through a
very interesting, though rather repulsive condition--the necessity of
getting rid of the dead to make room for the living.

What would be the result if no provision had been made for the
disintegration of the bodies of all the men and animals that have
inhabited the earth since the beginning? Such a situation is
inconceivable. But very wisely providence has provided that myriads and
myriads of tiny creatures are ever at work breaking up worn-out and dead
animal matter and reducing it to its original elements. These elements
are taken up by plant life, elaborated into living vegetable growth and
made fit again for the nourishment of animal life, thus completing the
marvelous cycle. And so we must not get the notion that all bacteria are
our mortal foes. We could not live without them, and our earth, without
their humble services, would no longer be habitable.

Neither need we fear the presence of bacterial life in our drinking
water. Drinking water always contains bacteria. We, ourselves, even when
in the best of health, are the hosts of millions upon millions of them,
and it is fair to suppose that they serve some useful purpose. At any
rate, it has never been demonstrated that they do us any harm under
normal conditions.

And so, the chemist was not alarmed when he discovered that the
formation of gas in his crooked tube gave indication of bacteria in the
drinking water. He must ascertain what type of bacteria he had
entrapped. To this end, he analyzed the gas, and when he determined that
the fermentation was due to the presence of colon bacilli in the water,
he sent out his warning. Not that the colon bacilli are a menace to
health. The body of every human being in the world is infested with
millions of them. But the presence of colon bacilli in drinking water is
an indication of the presence of a really dangerous thing--sewage.

Thus, when the city chemist turned from his test tube with the
exclamation, "Colon!" he did not fear the thing that he saw, but the
thing that he knew might accompany it.

There has been much discussion of late of the possibility that the great
lakes cities may suffer a water famine. The rapid increase of population
along the borders of these great seas, it has been said, might render
the water unfit for use. This fear is based upon the assumption that we
shall always continue the present very foolish practice of dumping our
sewage into the source of our water supply. The time may come when we
shall know better how to protect the public health and at the same time
husband the public resources. But even at that, the city chemist says
that he hardly expects to see the time when the present intake for
water near the head of Belle Isle will not be both safe and adequate.

No doubt he makes this statement because he has confidence that the
purification of water is both simple and safe. There are two principal
methods. The first, and most expensive, is nature's own--the filter. The
application of this method is comparatively simple though it involves
considerable expense. The trick was learned from the hillside spring
which, welling up through strata of sand and gravel, comes out pure and
clear and sparkling. To make spring water out of lake water, therefore,
it is merely necessary to excavate a considerable area to the desired
depth and lead into it the pipes connected with the wells from which
water is to be pumped. Then the pit is filled with successive layers of
crushed stone graduated in fineness to the size of gravel and then
covered with a deep layer of fine sand. This area is then flooded with
the water to be filtered, which slowly percolates and comes out clear
and pure. The best results in purification of contaminated water
supplies have probably been attained in this way; that is, as measured
by the improvement of health and the general reduction of the death rate
from those diseases caused by the use of contaminated water.

But when the alarm was given this spring by the city chemist there was
no time to excavate and build an extensive filtering plant. The dreaded
typhoid was already making its appearance and babies were dying.
Something had to be done at once.

If some afternoon you take a stroll through Gladwin park your attention
may be attracted to a little white building at the lower end of the
settling basin. It is merely a temporary structure yet it is serving a
very important purpose. Approach the open door and your nostrils will be
greeted by a pungent odor that may make you catch your breath. The
workmen, too, you will notice, do not stay long within doors, but take
refuge in a little shelter booth outside. Strewn about here and there
are traces of a white, powdery substance which seems to have been
tracked down from a platform erected on the roof. This is hypochlorite
of lime, the substance used for sterilizing the city drinking water.

This is so powerful a disinfectant that it destroys all bacteria in
water even in an extremely dilute solution. The method of applying it is
interesting. The city water comes in from the river through a great
tunnel about 10 feet in diameter. The little chlorinating plant is
situated on the line of this tunnel so that the solution is readily
introduced into the water before it reaches the pool called a settling
basin.

The hypochlorite reaches the plant in iron cylinders containing 100
pounds. These are carried up to the roof and poured into the first
mixing tank through a hopper fixed for the purpose. There are within the
building four of these mixing tanks. In the first, up near the roof, a
very strong solution is first made. This is drawn off into a second tank
with a greater admixture of water and thence passes into the third and
fourth. From the last it is forced out into the main tunnel by a pipe
and mingles with the great flood that is pouring constantly into the
wells beneath pumping engines. And this is the strength of the chemical:
five pounds of it mingled with one million gallons of water is
sufficient to render the water fit for drinking purposes. Nearly 98 per
cent of the bacteria in the water is destroyed by this weak solution.
The water is tasteless and odorless. Indeed, probably very few of the
citizens of Detroit who are using the city water all the time, know that
the treatment is being applied.

But the chemist continues his tests every morning. Every morning the
little crooked tubes are brought out and filled and carefully watched to
ascertain if the telltale gas develops which is an index of "death in
the cup." Thus is the city's water supply guarded.

No more important work can devolve on the board of health. Before
science had learned to recognize the tiny enemies which infest drinking
water, typhoid and kindred diseases were regarded as a visitation of
divine providence for the sins of a people. We now know that a rise in
the death rate from these diseases is to be laid rather to the sins of
omission on the part of the board of health and the public works
department.

* * * * *

_(The Outlook)_





Next: THE OCCUPATION AND EXERCISE CURE

Previous: A COUNTY SERVICE STATION



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