The Providence news. (Providence [R.I.]) 1891-1906, 1893-07-21

The New York Herald OF yesterday
discussed the question OF the filtration OF
the Croton water for the city OF New
York, and refers at length to the expert
ments being made by this city. 1t speaks
Of experiments maze in Germany and
elsewhere, and continues:
Equally interesting to physicians and
sanitarians are the elaborate experiments
with many systems OF purificaCion being
conducted by the city Of Providence. RI.
and now nearly concluded.
$50 exhaustive have been these expert
ments as 10 nat ural filtertng beds and as
to artificial filters that the deductions
reached will probably be accepted even
in proud and independent New York as
Of value in determining course TO
follow.
bv the commissioner Of public works,
Mr.. Smith the president OF he board of
health, DIR. Chaplin. and the city engineer,
Mr.. Shedd. As "A result the city OF Provi-
deDce will filter It's entire water supply.
The Providence Tests.
"TLe Providence tests have included
four distinct systems, two Of which are
natural beds in imitation of natural
porous soil, and two are an artificial
combination in tanks or retorts OF sand
or gravel
"One OF the natural systems is similar
to that In use at Berlin.
'The other is an Improvement on them
and Is design Of Engineer Shedd him
self.
"The experiments at Providence have
developed sharp rivalry between the
natural aud artificial sysiems
"The principles of all filtration are the
same. aud IL is only in the method OF the
Application that the artificial is dis
lu ral
The system with which 1t Is claimed
the best results have been attained Is "a
tank twelve feet in diameter aud niue
feet In height The bottom is composed
OF numerous small drainage pipes, COW
cred with fine screen, discharging into
large outlet pipe. On the surface of
thes. pipe screens Is layer OF coarse
ground sea quartz four inches deep.
Above that is layer of finer sea quartz
two feet eight inches deep.
Two Hundred Gallons n Minute.
"The unflltered wafer is discharged
into the tank at tho rate of about two
hundred gallons per minut, under fric-
tion head aad passed through the fne
quartz sand auu on into the discharge
pipes.
Into the water, az 1t runs into the Ill
ter, is discharged a solution OF aluminium
sulphaie. about one pound to 10000 gal
Ions OF water. This forms iaculent
precipitate, which Is insolublc.
"The work which these filters do in re-
moving bacteria and foreipn substances
from the water has been watched closely
and bacteriolo ical tests have been daily
made OF the filtered and unfitered wa
ter.
Caught the Microbes.
"The quantity OF water tested each
day In the comparative examination has
been one cubic centimetre--about half
teaspaonful II has been shown by these
examinations that water which as IL ran
I'M 10 the filter contained zoe, 900 bacteria
to the cubic centimetre only contained
two when filtered. This was reduction
of 800 per cent. aud the filler WIS run-
ming at "a rate equivalent to the filtering
of l30, 600. 900 gallons per acre.
"These experiments In germ catching
have been watche with gre Il interest Dy
Professor Charles A. Doremus, OF this
city; Pro 'essor Appleton, aof Brown Uni
versity, and Others.
DIR. Doremus's Views
i consider that the Providence ex-
periments are Of the greatest Importance
to the whole country said Professor
Charles A. Doremus yesterday. / am
sure nothing on the same scale has ever
Deen attempted in this country i is
particularly nteresting to this city,
where everybody agrees that something
must be done with the water. do not
think that the Providence authorities are
yet willing to make public the results of
all their experiments but they have
demo nsirated that IL Is possible to filter
polluted wat er in enormous quantities
up to ndreds OF millions of gallons-to
do IL quickly and cheap ply, and to serve it
to the consumer plre and clear. Bacte-
biological examinations OF the water
which have made show that b fore fill
tration it was dangerous to drink and
that the process OF filtering it had re-
moved from it all microbes and other
substances dangerous To health.
The question Of the publication Of
the water supplies OF large cities must
soon be taken up seriously. The analv-
sis OF the Pawtuxet water. winch Prpvi-
dence drinks, shows condition similar
TO hat OF our own Croton. There a plant
will be put in to filer 1900. 900 gallons a
day. IL is quite as practicable TO intro
duce plant to filter ten times that
quantity. which is the supply OF this