Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1913-07-29
Sterilizing Water With Light
MEANS OF uLTRAvoLET pIERs CAN BE FURNISHED
DRINK FREE FROM DEADLY MICROBES.

1t is highly important that good
drinking water shall be free from mi
crobes, because many disease germs,
such asethe bacteria of typhoid. cho-
lera, &c, are transmitted by water.
A single person has caused infection
to springs with typhoid and thus
caused epidemics in which many peo-
pie died. Hence modern hygienics de-
mands, first of all, sound drinking wa
ter for public distribution as well as
for private use. Many springs deliv-
er good, wholesome water, very low in
their microbic contents. particularly
in bactcrium coil How can these
sources deliver pure water if they are
supplied with water from rivers or
efiueats hHp WY Charged with the re-
fuse 4ofF towns and villages? Simply
by following the methods of nature.
Nature employs two means for purifi
cation. The first is the action of sun
or daylight on the microbes floating
in the water. 1t has long been known
that the sun has SO strong bactcrici
dial effect that rivers are purified some
miles below the entrance of city efllu-
eHt so that the water contains scarce
ly more microbes than before entering
the city.
The second means employed by ma
ture. for purifying water is filtration
over natural sand beds. such as river
alluyials, thereby mechanically freeing
the water Of suspended matter and of
germs.
Until recently only the latter process
has Been artificially employed. For
nearly so years water plants have
been provided with sand filter beds so
that the Water which they deliver is
hearty, always physically good. In
other words, il is free from suspended
matter Bacteriologically, however,
the watess is not always up to the
standard which modern hysienics de-
mands. For instance, Miguel, the fa
nous French water hysienist, 1e-
man9s for water Of the very best
duality a. microbic content not higher
than 10 per cubic centimeter. And the
number of hacterium coli must not
exceed 10 per LOCO cubic eentimetqrs.
To obtain such results the first one If
The above mentioned natural meth
DDS of killing microbes is now prae-
tically applied: namely, exposing Wa
teriefda or sterlizing action of the
sunlight Is due to the ultra violet rays
in the solar spectrum. Hence, we
must choose a light which is extreme
~ rich in these ultra violet rays. We
must create miniature artificial
sun. :. In. 1.-The quartz mercury Vapor
lamp. which closely followed the fun
damental work done by F. c. Hewitt
in illuminating mercury vapor lamps,
such source of ultra violet rays has
been found.
:: A typical European sterilizer is to
be found in one of the suburbs of Ro-
uen. France. For over two years this
instafla ton has supplied water steri-
lized by ultra violet rays. Since the
introduction of the system not sim
gle typhoid case has. been, known
among. the subscribers. whereas the
percentage of typhoid cases in neigh
boring districts is appreciabe.
The most recent types of sterilizing
apparatus are characterized chiefly by
the fact that they use the light in Il
more economical way than any appar
atus. hitherto constructed The prin
ciples involved are such that the con-
struetian. of very large sterlizng UNI
it'll is possible.
The apparatus consists of a tank or
long canal through which the water
flows. Battle plates are interposed Ia
stir mp the water as it flows. Into the
walls of this tank are inserted at ia
terSals of several feet, quartz tubes
fitted Water-tisht To vertical plates
constituting part of the walls of the
stcriliaing tank These quartz tubes
are abont two inches in diameter and
eight inches long. and are closed Al
thenends The vertical plates are pro-
vided with external metal boxes whicf,
carry the lamp supports. The lamps
are not unlike pistol in shape and
are characterized by a very narroT
U-sbaped luminous tube. of such
length and diameter that it nearly fills
the twe-iheh quartz tubes. All the
light produced by these pistol" lamps
therefore enters the water through
these quartz tubes. whereas the lan1n
itself is protected from contact with
the water by these same tubes. THIS