The Colfax gazette. [volume] (Colfax, Wash.) 1893-1932, 1904-04-15
WATER MADE PURB
). [. Armstrong Describes the
Plant at Oregon City.
All Mineral and Foreign Substances
are Removed, Leaving the
Water Pure and Clear,

In order that the citizens of Colfax
might understand the working of a
water filter, The Gazette interviewed s.
Z. Armstrong after his return from Ore
gon City, where he inspected the tiltering
plant IN use at the water works in that
city. Mr.. Armstrong, in discussing the
plant, described it as follows:
"ln Oregon City the water is taken
from the Willamette river through a
conduit, similar TO the one in use at the
water works in this city, and s carried
through pipes to the settling tanks.
two IN number, each OF which is 16 feet
in diameter and l6 feet high The water
passes into these tanks about four feet
from the bottom and it requires about
20 minutes to fill them, thus giving it
about that amount of time to settle as
it passes through.
Just before the water enters the
tanks, a solution of sulphate of alumi-
mum or commercial alum liz added, the
proportion being about one half grain
per gallon. This incurs an expense OF
not to exceed so cents DER day, and
cOagulates all foreign matter in the
water by the chemical combination
which is formed. All of these substances
are precipitated in the form of a sort of
feathery sediment, and the settling
tanks catch a great deal Of this az the
water passes through them to the filter
ing tanks, OF which there are two in
number, each l 5 feet in diameter.
Each filtering tank contains a bed of
about four feet of crushed quartz, or
sharp sand, there being about "a, 900
pounds in each The water passes
through these tanks of it's own weight,
there being no pressure whatever and
the sand collects every particle Of cOagu-
lent and removes all sediment. rendering
the water 50 to 80 per cent pure, accord
ing to the analysis of the state chemist
Of Oregon. This il from water badly
contaminated with sewerage
The filters need cleaning on an aver
age of once every II hours, but may run
for "a hours without any material
harm. The process OF cleaning requires
a reverse of pure water from the reser-
vOir through the sand, passing out
through a waste pipe. The sand is agi-
tated by means of crOss-arms reaching
across the tank in all directions from q
center rod. which is revolved by a small
water motor run by pressure from the
reservoir. The water which passes
through the motor falls into the clear
water basin located under the filtering
tanks. In this way no water is lost and
the only loss incurred is the pumping of
the same water into the reservoir again,
WhIci4 in itself IS q very small item Ii
takes about 20 minutes to clean the
filter.
"The pumping power Of the plant is
not applied to the filter in any way, the
pumping to the reaerv DIR being directly
from the clear water basin, the same as
from our settling we'll The filters re-
quire no attention, except when clean
ing, and the pumps do not have 10 be
stopped during that process, there being
no direct connection. The settling and
fiitering tanks are built above the
ground and the clear water basin is be-
low the surface.
THE people Of Oregon City are very
enthusiastic over their water system as
it now stands, and it is not necessary to
ask them regarding their plant If you
are a stranger they want you to test the
water Immediately. They claim that it
is better water than is furnished Port
land, which has a reputation all over the
country. la Oregon City the pumping
plant and the filter are about 100 feet
apart and run constantly, furnishing
100000 gallons Of water per day.
lhe pumps operate under direct pressure,
one into the mains and the other to the
reservoir. The pump that feeds the
mains is under 80 pounds pressure and
the lifting pump, which throws the water
to the reservoir, works under o pressure
of 185 pounds. They employ a night
and day man, but Colfax would need
10 more help than is at present en-
ploYed.
"The filters need absolutely no press
ure except the weight OF the water, there
being just enough elevation for the water
to pass from one tank to the other. The
amount of water that the tanks receive
is governed by floating valves, and ust
as much water will pass as will flow OF
it's own weight, there being about one
foot of water on the sand all Of the time.
"There is no question in my mind but
that filter will make our water as pure
and wholesome as it does at Oregon
City, or any other place. | think that
is self evident from the effect the filter
has on water from the willamette and
also from the effect the cO-agulent used
in the filter has upon water from the
Palouse river, which | have dem0nstrat
ed by test.
''Place the proper proportion oil alum
in water and it will precipitate all for