Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1897-05-16

tho Chicago river, had been consise...
as n maximum test FOR this big plant. r.,
better selection could have been mad,
than the Mississippi river. While the bc1
OF this river Is composed 20 a great extent
OF constantly shifting sand. there Is a
all timesfa pronounced sediment In n,
water which gives 1t that peculiar yellow.
ish color, which has made II famous "A
the only real water in America that hard.
ly resembles water at all. with the az.
cepticn that Il is liquid In form. Al GER
tain seasons OF the year, II "A glass q
flied with Mississippi river water ana al.
lowed 20 stand for a lew moments. BE-
Will be found that almost one fourth %
the glass. from the bottom Up, Will con.
tain llauld mud That is Why ID Is q,
often said that the persons who dfins
unfltefed Mississippi river water absorb
their peck Of dirt every foriy-eight hours.
: So the task Of the big liter plant al
Davensort ~ no LIGHT one ara tn
amount OF dirt and impurities that ar,
removed from the $4,000 gallons tht
filters contain Is naturally tremendous ir
quantity. Especially does this iart pfOFt
impressive when II Is considered that iht
$4,000 gallons the iliteis hoid SIMPLY con.
stitute the amount that IS ln them 40 ID
times. OF course. the water Is constaaty
changing Nearly every moment 10 ID
being pumped out into the th.gty-sefcs
miles Of mains that wind Ike huge snakei
beneath the surface OF DaVcnDurti
streets To litter the entire water supply
of a city is a gigantic task.
Tho method of filtration Is interesting
and entirely new, because II must be re-
membercd that there IS not In existence
any filtering plant that approaches tal
in magnitude or compieiene-t DO inc wy
+ of possessing every requisite Tor removing
impurities from water. Ia the ifst place,
the water. as II comes from tne 4nssI.-
sippi via the tunnel beneath the rivers
bed. IS forced By pumps through D-inc1
feed mains into the filters. Then - pasfes
downward through FIVE feet Of sand. and
thence through peculiarly shatel screen
consisting OF extremely line sits saHei
through cylinders OF heavy seamless
tubing. After this il goes into the mains,
and Is forced out 10 the consumer.
Now. look at the water and compare II
with the muddy, amber-cOlored fluid mat
flows into the filters from the tunnel. II
has become as bright as clear ana as
sparkling as II II came nom a spring
The sediment and all the microbes that
the unhltered water Yields necessarily re-
main on top Of the sand IN the filters.
IL IS In the economical and certain re-
nioyal of this impure matter that tina
chief excellence Of this great plant lies.
The process OF cleansing the SAND IS not
unlike that operative In hydraulic mining.
Thousands OF fine, pOWefful jets Oh "tIei
are applied directly TO the pace Wheis
the impurities are lONdA'As - .N'' "''t'N
time the sand IS washed by forcing the
water upward through the ped on saAl'
instead OF allowing the water 70 penetrate
from the top 10 the bottom. VI course,
this process renders IL necessary Tor soma
Of the water that has been rendered pure
to be forced back. but II is uttered again.
ard. therefore, nothing - really lost,
These lets Of water that are used IN
cleansing the sand come through horl-
zontal perforated arms, running from
central vertical pipe. which in turn Is az
fachpd TO a piston in such way that py
admitting the water pressure from me
mains to the piston the perforated arms
referred 10 are forced downward and BACK
through the filterlng material mus mo
washing Jets. each OF which IS 3-l6 or an
inch in diameter. are directly appnet
OF sand that is I'm the hitter. The result
OF all this is that each separate particle
of the filters contents IS turned around
and ground until IL has practically been
secured Then. when all the impure mat
ter has been collected and floats IN the
water at the top of the sand USED Tor NJ
tratiOn purposes, j Is forced pacN mo
the river again throush a. uraln . lna, -
constructed especially for that purpose
one would naturally think that Wnere
ALI this was done constantly there would
be no trouble about keeping the water
pure. But no chances are taken. ana IN
order that not the slightest impurlty may
remain. the filter and sandbed are sterl-
ICED. This Is the last blow, so TAR as the
uicrobe and his attendant evils are con-
cerned The water Is as pure as X ~
possible for water to be. with the result
that the little city Of Davenport has the
only absolutely pure water supply or any
city in the United States, II not In TIT
world.