The Portland daily press., 1884-01-03
BOsTON's NEW SEWERAGE sYs-
TEN.
Admitted by French E gineers TO be More
Perfecs Than That of Paris.

Boston has put into operation the improved
sewerage system, which hts been some years
in preparation, and which will take rank as
one of the greatest engineering feats of the
age. The sewerage system of Paris has
generally been supposed TO be the most perfect
in existence, but it is now admitted, even by
French engineers, that the Boston enterprise
must take the first rank.
The project was conceived several years ago
by Mr.. Joseph P. Davis, the then City En-
gineer. The primary object of the plan, in
brief, was to intercept the sewerage of the city
as it flows in the existing sewers and convey it
to point where it may be discharged with
safety to the public health. and with the least
injury to other interests. The intercepting
sewers follow the marginal streets of the city
as far as practicable, that the sewage may be
intercepted near the outlets of the existing
sewers. The main sewer carries the waste of
the city first to Old Harbor Point, where it ar
rives forty-three feet below high tide level.
-Four great engines, each with capacity to
raise 25,000,000 gallons forty-three feet in
twenty-four hours, lift the sewage into the dis
charging sewer. The great flood is strained
through fifty cages, and flows for two and six
tenth miles into reservoirs at Moon Island.
1nlS aiSCHarSluB SeW6f lS ulVlQ6u INTO tnreo
sections, known respectively as the tank or
deposit sewer, the tunnel under Dorchester
Bay and the large sewer from Squantum Neck
tn Moon Island. The deposit sewer ia about
1900 feet long, and is carried upon an en-
bankment extending into the bay to the west
shaft of the tunnel. Its elevation Ia such that
sewage will flow from it to the reservoir by
gravitation. Tho tunnel, with it's west shaft,
forms an inverted sphon, passing under the
navigable waters Of Dorchester Bay. It's
horizontal length is about 6,970 feet, and the
average depth of the shafts below mean high
tide is 40 feet to the bottom of the tunnel The
siphon has first vertical descent of about 150
feet, next q nearl- horizontal stretch of about
6,0I0 feet, and, lastly, a rising incline of one
loot vertical to every six feet horizontal.
AT Moon Island, where the sewage is dis
charged into deep water, there is large reser-
voir covering several acres. IL has four apart
ments, and will hold nearly 25,000000 gallous.
Its design is such that 1t can be convebiently
enlarged at any time to double this capacity,
TO meet the needs of the city's increased
growth.
The London reservoirs are covered with
brick arches and earth, but it is hoped and ex-
pected that it will not be found necessary to
cover this one. AS a precaution, however
foundations Tor columns have been built that
wooden covering may be put on if ex-
perleDce should prove that one is needed. A
large number OF gates are provided for admit
ting and dlschargiug The sewage, which are to
be opened by hydraulic PRESSURE as are those
at the pumping station, The last link in the
extensive chain of works is the outlet section,
whlch contains four sewers so arranged as to
connect with he outfal sewer in receiving
| the discharge from the reservoir and carrying
| IL out TO the tidal current at the end of Moon
| Island. The entire cost of the system has
been $4,544,272S9