The times. [volume] (Richmond, Va.) 1890-1903, 1897-03-28


ton. oxidation and dnution. all Of which
tend to its publication.
The filter plant IS in itself a most mar
vclous sight Each of the filter shells
/ is - feet I'm diameter and % feet long.
They are built of homogeneous steel OF
( tensile strength. The water company has
so far built about thrty-seven miles of
mains. into which the purified water
! flows from the filters.
/ Despite the fact that there are ten
/ filter shells. so delicate IS the cOnstruc-
| tion. from a mechanical standpoint, OF
/ the entire plant. that the filters can be
used either one at time or III their
/ entirety. as circumstances may make IL
advisable. AS an indication Of the effort
| that has been made TO provide this plant
with every possible means Of purifying
/ the water. 70 may be stated that each
| filter is about thrce-quarters fun of white
| sand. amounting TO about thirty carloads
! FOR all the filters.
This sand Is brought from Horn IS
! land. i'm the Gulf of Mexico. The peculiar
! nature of this sand is that each grain
| is Of almost equal texture and perfect
crystal This is brand now. and very
: costly departure. The ordinary sand that
I is used for altering purposes is porous.
and. therefore. does not in all respects
] answer the ItfINli 'llif|li nus INV
/ ever. is the first time that city Of any
! size has so filtered its water supply.
70 must be remembered that water al
wavs contains microbes Sometime they
| are so inhnltcsimally small that only
magnifying-glass Of exceeding power VIII
( detect them. If there were no sand I'm
the filters that was absolutely imper-
vious 10 the attacks of the microbes
| these little seeds Of death would be quite
! likely to find Judgment in the pores OF the
: sand. There they would die and rot. and
i'm a short time the sand would become a
fruitful source Of disease rather than a
plant TO purify water This is why Horn
Island sand is used I'm Davenport.
} II all the rivers In the country. barring
! the Chicago river had been considered as
/ maximum test for this big plant. no
, better selection could have been made
! than the mississippi river. While the bed
/ of this river is composed To great
extent of constantly shifting sand. there
! is al an times a pronounced sediment III
| the water which gives il that peculiar
| ycllowish color which has made il IA
| NOUS as the only real water I'm America
| that hardly resembles water at all. with
! the exception that d. Is liquid i'm form.
/ At certain seasons of the year. II glass
be filed with Mississippi river water and
allowed TO stand for few moments. IL
! Will be found that almost one-iourth OF
the glass. from the London mp. viii con-
| tain liquid mud. That is why u IS so OF
/ ten said that the persons who drink I'M
| filtered Mississippi river water absorb
! their peck of dirt every forty-eight hours.
So the task Of the big filter plant at
| Davenport is no light one. and the amount
! of dirt and Impurities that are removed
/ from the 800 600 gallons the h'ters con-
tain is naturally tremendous IN quantity.
| Especially does this fact prove impress
/ give when it IFS considered that the a5D,-
| Geo gallons the filters hold simply con-
stltute the amount that is IN them at
! an times or course the water IS con-
! stantly changing Every moment II Is
/ being pumped out into the thirty-seven
. miles Of mains that wind like huge
/ snakes beneath the surface Of Davenport $
/ streets To filter the entire water supply
( OF q city is % gigantic task.
The method of filtration is interesting
/ and entirely new. because it must he re-
! mcmhorod that there is not In existence
any altering plant that approaches this I'm
+ MAGNITUDE or completeness i'm the way Of
possessing every requisite for removing
/ impurities from water. I'm .hc first place.
] the water AS it comes from the Misss-
sippi via tho tunnel beneath the rivers
bed is forced by pumps through twenty
inch feed mains into the filters. Then IL
passes downward through five feet Of
sand. and thence through a peculiarly
shaped screen. consisting Of extremely
fine Sits sawed through cylinders or
heavy seamless tubing After this II goes
into the mains and Is forced out 20 the
consumer
Now look at the water and compare II
with the muddy ambor-colored fluid that
flows into the filters from the tunnel II
L has become as bright. as clear and as
sparkling as If u came from spring.
The sediment and all the microbes that
the unnltercd water Yields necessarily
remain on top Of the sand In the filters.
II is in the economical and certain re-
moval OF this impure matter that the
chief excellence of this great plant lies.
The process Of cleansing the sand Is not
unlike that operative in hydraulic min
ing. Thousands OF fine. powerful Jets OF
water are applied directly TO the place
where the impurities arc located. AZ the
same time the sand is washed by forcing
the water upward through the bed of
sand instead Of allowing the water 20
penetrate from the top 20 the bottom.
/ or course this process renders IL neces-
sarv FOR some OF the water that has
boen rendered pure to be forced back
but n e. filtered again, and therefore
nothing IS really lost.
rrbose lets OF water that are used In
cleansing the sand come through hori-
zontal perforated arms. running from a
central vertical pipe. which In turn Is
attached TO piston I'm such way that
by admitting the water pressure from
the mains 10 tho piston the perforated
arms referred TO are forced downward
and back through the altering material
Thus the washing Jets, each Of which Il
49, .tvto -