Evening star. [volume] (Washington, D.C.) 1854-1972, 1880-10-23

their own remedy in failing to appear through
out the open canal: II the arch were removed
with 1t. The necessity for the arch to facilitate
travel in the streets, entails the necessity for a
thorough and systematic ventilation OF the
covered space. At present this part OF the
sewer has very little ventilation. 1t Will
doubtless be advisable to isolate the system of
ventilation OF the tidal portions of the main
sewers, arreSt1ng the motion OF tina gases at the
upper limit Of the tide, and turning them into a
yentilatiDg shaft; introducing at the same
point some mechanical device for inducing the
assimilation OF the sewage and its aeratiOn by
mechanical agitation. Grated openings at ShorG
intervals along the line of the arch will tempo
rar1ly answer the purpose of ventilation. The
the flood, has been thought to be a disadvant-
age, but 1t is quite the reverse. Any agent
which induces motion in these gases can be
taken advantage OF TO withdraw them from the
sewers and replace them with fresh air. The
rise and fall OF the tide Is such an agent and
requires only intelligent control. 1t is Just here
that such an agent Is needed, for 1t is probable
that nearly all OF the sewer gas, not due to de-
fecttye plumbing in houses, is generated in the
tidal sections OF the sewers. Above the infiu-
ence OF the tides, the sewers have, all, con-
slant outflow and a size adapted to storm
water. Their oval shape concentrates the dry
weather flow Of sewage In the tnvert, and the
large air-space above this is favorable to
prompt oxidation Of such gases as may form
during the short time occupied In flowing to
tide water. The grated manhOle covers, at short
intervals, effect perpetual renewal OF the air.
AIR AND WATER CURE.
Water is literally provided by the present
rate OF water supply, but is not now, well dis
tributed through the city. Owing to INSULT Gent
head In the mains, the higher levels have not
an adequate supply, but this will be remedied
with the introduction of the new water supply
for the District. The principal main sewer OF
Georgetown furnishes an example OF the sue
cessful working OF the system upon which Lon
don still depends-air and water cure-w1thout
"a -fln MT a IN n w
construction. This Is large Semi-circuar
sewer on vertical side walls, with fiat wooden
floor. 1t is more than fifty years old and requires
water course, and is OF a size TO carry the storm
water, draining the greater part OF the most
thickly. settled district OF Georgetown. The fall
is very rapid-about $50 feet In four-fifthS OF a
mile. In its lower part the stream becomes
cataract, which plunges under the water-wheels
OF two large mills and receives the waste water
over a rocky bed into the river channel. where
the latter has depth OF thirty feet. The outlet
OF this sewer presents no evidence whatever of
its character. The sewage disappears forever
without sign.
! attribute this result to the copious admixture
OF pure water In the sewer, the large size OF the
latter giving access to plenty of air; to the
rapid cOnveyan ce of the diluted sewage into an
unlimited quantity OF pure water; and to the
thorough assimilation OF the sewage by the
water and its aeratiOn in tranSitu, Induced by
the mechanical agitation which 1t receives.
Wherever the same conditions can be attained,
1t is reasonable to suppose that the same results
will follow.
WATER CARRIAGE FOR SEWAGE.
With the admixture OF sufficient quantity
Of pure water, sewage becomes so diluted and
dtfused as to be harmless. At some point OF
dilution the scrupleS OF even the opponents Cf
water carriage for sewage must disappear. The
fact is recognized In all such systems which
provide for its conveyance TO remote localities
condemned to Its special reception. The long
lines OF interceptfng sewers and The Outfall
cOnduitS are only of limited capacity, and are
made to overflow at every convenient point,
into the nearest water course, whenever a
moderate rainfall diluteS the sewage and in
creaSeS its bulk beyond the capacity of the con-
duit. AS long, then, as sufficient water can be
provided for the purpose at less expense than
the cumbrouS and complicated system OF distant
transfer to sewage farms and filtration areas,
it will be better to provide the water. For
the next twenty-five years an additional
supply equal to five times the pre-
sent one would probably suffice. 1t can be
brought In by conduit one half the length of
that required for sewage farm. The capital
lied cost Of the pumping alone for the distant
removal of sewage, predicated upon future
water supply OF 5O,O0O,000 gallons per diem,
would be about 81 100000. This is the estimated
cost OF the new water supply, including an ad-
dit1onal reservoir and extensive land purchases.
and having an available capacity OF 125, 100000
gallons per diem at 40 feet above tide. Tdere
can be no question as to which expenditure
should precede the other.
RRCAPITULA ALTON.
TO recapitulate, the work now projected, and
in progress, contemplates the reclamation OF
the flats along the water front Of Washington
ard the rectif1cation OF the channel of tie
river. 1t provides for the effective drainage OF
Washington and Georgetown, and the adapta-
ton or The system OF drainage to sewerage as
we'll providing In such manner for the possible
eparation OF the systems. at some future time.
hat While the combination OF the two shall be
made to the best possible advantage, all OF the
u ork done in that direction shall BE- applicable
20 tne separate system of sewerage. It conten-
plates, as the Indispensable prerequisite OF any
:! stem OF sewerage by water carriage and Of
any reas onabie condition or health and comfort
consistent with modern civilization, the intro
iuction OF liberal water supply at sufficient
elevation.
WATER SUPPLY.
In my last annual report 1 submitted esti
mates for extending the conduit from the di5-
tribut:ng reservoir to the high grounds north of
washington 1} and for laying four foot iron
main thence 10 re-enforce the present mains.
The necessity for this work Is increasing. and
the complaints OF scarcity OF water on the
higher levels cannot be quieted by any tenn
mains. While The result OF Introducing larger
mains into the permanent distribution system
Will De an ultimate advantage, the present
elect Is only ineager addition to the supply OF
one locality at the expense OF that of another
and satisfies nobody. The level Of Distribution
OF the necessary supply or water is rapidly fall
consumed. Any measure, like the application
OF meters, which will restrict the CONSUMPTION.
viii raise this level; but with the free use of
water the level must be sustained by Increased
Conduit capacity or by pumping. Pumping is
not 1uStiflable. except as a temporary eXpe-
dlent: for water consumed below the level OF
possible gravity supply. The Georgetown high
service pumping district is above this level. and
viii have 10 be maintained. The Washington
h1gh-seryce district is below this level and its
creation is temporary expedient to assist In
t ekiDg cut a scanty supply Of water.
Just north OF them, and which they are
intended 10 supply. They are unable to per
FORM the duty now Imposed upon them, and
while diverted to the supply OF northern WASH
1ngton, they cannot be OF any service to the
elevated district to which they belong. The
cost OF pumping the supply SO diverted, capt.
as me cost or transportation TO the city should
suffice for the whole area of Washington nov
supplied by pumping, excepting perhaps few
me pumps. To reduce this cues
lion OF pumping to basis for
comparison with a gravity supply ! assume
that the present supply OF "a 600 COO gallons par
dlen, Which is inadequate, should be increased
10 A GOO. Geo.. This amount can be brought to
ne city by the present mains, and is the limit
ol tnelr capacity for partial distribution by
pumping. The case u.s. therefore, the most fay-
oTaoie one fer the pumping plan requiring no
outlay LOT conduit pipes to the pumps
Georgetown would continue to be supplied as
at present. Washington would be divided into
q llgD-SprYlce and a low SerVtca DISTRICT nv tbo