The Ely miner. [volume] (Ely, Minn.) 1895-1986, 1940-10-24
CITY Water
Continued From Page One0


to displace the lighter water. Thus a
vertical current is established which
continues until the water on the bot
tom and throughout the depth of the
lake is the same temperature and then
as the surface chillS further, it becomes
lighter than the water on the bottom.
How long this vertical current continues
depends on the rapidity of change in
temperature, of the air. This is spoken
of as the turn over period" of lakes.
In the spring We have just the reverse
of the process.
"These vertical currents disturb the
mud and silt on the bottom of the
lake and release the pent up gases and
other products of decomposition of the
vegetation which has settled on the
bottom and should we permit the water
to go through without taste removal,
the complaints would be plenty.
Heretofore we have used activated
charcoal, pulverized and fed by machine
to the water. The charcoal would re-
move the tastes by absorption and the
filters would remove the charcoal. This
process has some disadvantages but it
has it's values as well.
1.-THE more recent and up-to-date
method is to oxidize the vegetation by
super chlorination at what is called
the break point. The normal amount
of chlorine added to water to- destroy
| disease producing bacteria does not
oXidize the organic matter. The OK
idizing effect takes place with larger
doses and the break point is to be
found by series of jar tests on the
untreated water. Every water supply
has a different breakpoint and must be
determined separately. With the aid of
representative of the chlorinator COM
pany, we determined the breakpoint
of the water we treat at the plant, then
started plant run on that basis. The
fact is that somewhere we overlooked
some factor and instead of getting COM
plete reduction of the organic matter,
we got partial reduction and among the
end products was a phenol compound
which combined with the chlorine to
give us chloro- phenol which is the
medicinal taste which you have tasted.
"Chlorophenol taste troubles are COM
mon ailments to water works men who
must treat surface water supplies and
we have been fortunate in not having
more of it. A small amount of it es-
Gaping in to the system difuSeS through
the entire system and it is detachable
to the taste in very minute quantities.
The storage capacity which we have is
large and with the public demand at
present about 100000 gallons per day,
it takes about five days to displace the
bad tasting water with better water.
Since Saturday night. the filters have
been giving satisfactory water and the
chloro-phenol taste should disappear
''The best comparison of the taste
which heard was from man who had
been drinking whiskey with the city
water for a chaser" He thought he
had been drinking Scotch whiskey until
he found out different, that it was
bourbon. During the prohibition days
when the big bootleggers made imita-
ton Scotch they impaired the char
acteristic smoky taste of real Scotch
whiskey to their product by adding
small amount of phenol This man
was getting the Scotch taste to the
bourbon from the chlorophenol in the
water he used for chaser. Any man
with that keen sense of taste could
qualify as blender for distillery"