The Providence news. (Providence [R.I.]) 1891-1906, 1894-08-07
Cost Of Sand Bed Filters Per Acre.
Cost Of Maintenance.

| fougnkeepsic.N N. Y.............. l3lp7l q
""'uoAes' "iAss'' ss''....s........... 55,52 "
Cost Of Maintenance.
The exceptionally low cost of the Law.
renee beds, S30,0O0 per acre, was owing tc
the fact that they were practically
constructed by nature, before work
| on them was commenced, there
oeing shoal at this point.
which rendered the FIRST cost and annIi.
cation light. The original estimate OF
tne engineer for these beds OF two and
one naif acres, equipped complete, being
only twenty thousand dollars s2O, 900.
Inc cost OF maintenance of Poughkeep-
SIC niter beds is estimated by Mr.. T. w.
DAVIS, formerly engineer and superinteud-
ent OF the Poughkeepsie Water Works ma
follows per million gallons:
running the water through the beds 60 30
"ater USED Tor washing sand, supplies,
'''""''"''.'''.'...' ',.............. 10
ai'''''''................ .....,... 90 90
The estimated cost for maintaine the
Mechanical system at Providence, per
i'""'o0o gallons, was 1892.
As to Leakage.
Mr.. Shedd makes no reference as TO the
construction of the bottom of the pro-
posed filters. 1t would be well to know
whether or not he includes a water-tipbt
bottom and sides.
says Piefke, the great filter expert:
oumce 1t to say, that the bottom must be
wster-tight, and the sides strong enough
70 support the pressure of the enclosed
water. Those at Berlin Stralaw are laid
upon clay (Thom) covered with concrete
Mr: L. w. Davis Gays of the Poughkeep-
sic Water Works: "The masonry must be
o! sumcient strength to stand the weight
OF tne water when the beds are in opera.
tion and also the thrust OF the earth or its
backing when the water is re-
moved. They are filed with |
water, and at the time of |
''eening the water IL drained off: that
masonry must be wster-tight; 1t, further
more, must be OF such o character as to
'.ano the frosts of winter, and In connec-
ION with an alternately wetted and dried
ulisce, which gives masonry a severe
The present superintendent of the
oughkeepsie Water Works, Mr.. Charles
:. rowier, states that they are now losing
lesriy twenty-five per cent of their fill
ereu water, through leakage. He states
ms report for 1890. Leakage
= eoveiopeo In the wall, separating
no two beds to such extent in
no early part OF the year, that one bed
ould no longer be cleaned while the
'ner was In use, and 1t became necessary
employ additional help for cleaning, I
ntil the sand was lowered sufficiently 70 :
ermit the wall to be repaired
And again, in his report of 1893: ssTba {
akage has existed in the present beds {
ON their construction, Is increasing and {
It continues, will soon necessitate the {
moval OF the entire filtering material To s
liable repairs TO be made, an undertaking 7
lat will require the beds to be thrown
II OF use two months or more. The sd- a
tional beds should be in readiness for v
% at such time. Second. with T.
II single set of open beds, we are too il
uch subject to climatic conditions. "
lese beds cannot be cleaned during a tl
'rm OF rain or snow, or freezing weather. t
fall OF few inches of snow during n
'aning, stops the work entirely. Il
avy shower OF rain occurring on sum b.
" afternoon, just AZ the work of clean IL
Is nearly completed, and before the W
Ter Is let on, will frequently undo the 1t
*, and necessitate another cleaning,u al
Climatic Difficulties. y, ~
would also be interesting to know fu
etner Mr. Shedd's estimate includes 81
erection OF water-tight wall above
n-water mark, surrounding the fit ers, Tn
whether he has provided for the nee ur
Try engines, boilers, pumps, electric an
ut plant, sand cleaning machinery and wa
yer, and for a bridge across the Paw RET
et river. be
lr. Shedd does not propose In cover mC
80 filters. Then why should he insist Nj
the expenditure OF sixty thousand dol fol
(s60 0,0OO) for buildings to cover a mo- mt
nical plant, operating at a velocity Of
1900 gallons per acre, when IL is nm wa
sssary for those of his own which he gre
poses to operate ct velocity of 1000. tic
gallons per acref wo
efke, recommends that the reservoir car
Uttered water should be coyered: NOT Un
to avoid disturbances through the hit
of ice In the winter. but STR
cially to exclude light.n ing
r. Hiram +. Mills, M. Am. c. f.. and gal
nineer OF the Massachusett, STATE pre-
d OF health, says: "To obtain as N
result In q cold New England rs Z
er, IL Is necessary to defect the sur Tha
OF the filter bed, SO that IL will by
freeze. III the sand freezes at the sur feet
the sewage thaws In places here and exp
and passes too rapidly through the :"
In sections having less than the OF
. area of bed; air is partly excluded. max
nitriflcation is checked. A closed tent
which will keen snov "a -. | cal