The Ely miner. [volume] (Ely, Minn.) 1895-1986, 1937-10-14
Elimination of Red Water
Troubles in Local Service
Lines Aim of Ely Chemist
Dr. j. E. Thompson Traces History of Ely Water Supply and
Steps Corrosion in Service Lines at ST.
Paul Waterworks Conclave.

With their not water pipes ana UdlkS
continued to have the same trouble
. We tried to dismiss them from oul
mind with the explanation that they
must use greater quantities Of hot water
land thus greater corroSion and more
noticeable red water. Cast iron laundry
stoves have been blamed by the local
plumbers as being one of the worst Of
TENDERS. The apparent explanation has
been that the iron in such stoves more
easily goes into solution. We noticed
that the return pipe from the heating
element to the tank might last only one
or two years before it sprung leak or
became checked with red encrustation
The pipe from the tank to the heating
element might last ten or more years.
ALI of these above facts were noticed
for a long time but We sought no
definite explanation.
In 1888, we had better conditions at
the filtration plant to work with and We
again began using soda ash and con-
jtinued same until July, 1885.
| Our raw water which had variable
PHI from 81 to TO was raised by the
soda to 70 to 7.6. The soda treatment
never gave us a uniform PHI. We fed
as much as three and four grains per
gallon to obtain these results. In 1885
We change from soda ash to hydrated
| lime and We are continuing that to this
date. The hydrated lime is fed in eX-
cess and We reach a Saturation point or
carbon dioxide balance at a PHI of TT
We get uniform PHI and in all re-
Spects more satisfaction. The excess of
| lime deposits III the Sedimentation basin
and several times year We shut off
the lime feeder so that the excess may
be taken up in solution. When the
PHI begins dropping below 7.3 we know
this has happened and the lime feeder
is started again.
Since We began feeding lime, we have
from time to time opened hot and cold
water piping to observe the effects of
the lime treatment. The cold water
pipes show film and in some places
small tubercles of lime deposits and
apparently most of the corrosion has
ceased. Dripping cold water faucets do
not produce the rust stains Upon OBJ
serving hot water pipes, we noticed the
lime film only during the first year and
now in the third year corrosion is again
definite. However, the plumbers in
form us that the length of life of the
average piping has increased. We hear
much less complaints of red water from
the consumer, but it is apparent that
much more improvement can be made
to cut down the nuisance and the cost
to the consumer from the corrosiveness
of our water.
Since the trouble has been practically
eliminated in our cold water service
lines and it still is noticeably present
in our hot water lines, We have sought
an explanation We took cold tap water
and heated it in an open flask, check
ing the PHI at every ten degrees rise
in temperature. Commencing at $50
degrees F. we began noticing drop in
the PHI and this drop continued until
ITO degrees F. When heated beyond
that point it continued to hold the same
PHI as reached at ITO degrees F. We
started off with cold tap water at PHI
~ and it dropped to PHI IA. In as
much as these tests were made in an
open flask, We thought conditions under
pressure in the piping might be diff
ferent. Therefore, we sought out some
of the residences in which the hot water
piping is Of relatively short life. We
found almost the same conditions
These people kept their hot water at a
temperature in the neighborhood of
ITO degrees. The PHI drop was prac-
tically the same and always it reached
its peak at ITO degrees F. The odd
feature with this hot water is that
when it cools the PHI goes back to
where it was before heating. The ex-
| PLANTATION of all this appears to be that
We are producing a chemical change
in our water by heating it and par
ticularly when it is heated up to ITO
degrees F.
There apparently are produced Or
ganic acid compounds of unstable
nature and these acids expend their cor
rosiveness on the piping near the heat
ing element and in the hot water tanks,
and their immediate viciity. When we
notice long hot water lead from the
hot water tank the corrosive action is
most noticeable near the tank. This
apparently explained by the tempera-
ture of the water dropping to point at
which the organic acids are unstable
AS further proof we can cite electric
hot water heaters which are set for 14O
degrees F. Corrosion and red water
complaints do not come from such
places. Cast iron laundry stoves and
other similar hot water heating ele-
ments can, therefore, be blamed pri-
marily because of their effectiveness as
heaters, producing temperatures up to
and above ITO degrees F. If there were
a way to regulate the temperature of
these stoves as there is with the electric
equipment most of the objection to
them would be removed
/ The lime treatment of our water SUD-
ply has caused no complaints from the
consumers In adding lime to the sat
uration point we naturally introduce
hardness. This is found to be 26 ppm.
This has no appreciate effect in per
capita soap consumption. We are con-
sidering raising the PHI still higher with
the aid of soda ash, Although our
raw water PHI fluctuates, our treated
water PHI continues to remain the same
with lime treatment. Having a uni
form PHI to begin with, uniform feed
of soda ash should produce uniform
PHI. 1t appears as if this can be &C
complished with about grains per GAL
Ion of soda ash to reach PHI 8.5. This
combined lime and soda ash treatment
should give better prevention of cor
rOSion in our hot water lines.