Little Falls transcript. [volume] (Little Falls, Morrison County, Minn.) 1876-1894, 1892-06-24
OF PRESENT INTEREST.
Information That Is Reliable About
Different Systems of
Sewers.

DAOA OAV ~ oVOAAS VI
Sewers.
=. The following article was pre-
pared by j. C. Temple, hydraulic
engineer Of great experience, and the
facts given will be interesting as the
city is about to construct system
Of sewers.
The problems of municipal
sanitation relate to the disposal of
refuse or dry matter from streets,
dwellings, and Industrial establish
ments, waste water and sewerage
from houses, shops and streets,
storm water and subsoil water
Formerly the reason for removing
and disposing in various ways of the
above matter rested simply OH a
desire to preserve an agreeable and
decent condition of affairs within
the city limits, but in recent years
the subject has been regarded with
increasing interest from hygenic
point of view andssyarious more or
less theoretical assumptions have
been made concerning the relations
between municipal cleanliness and
disease. 1t is not the purpose of
this article to enter into discussion
of the warriors theories but to give a
general idea Of the methods in use for
sewerage disposal. Two systems
are recognized and are used with
various notifications in this and
other countries.
The combined system has for it's
object the removal by means OF
sewers of sufficiently large sections
all refuse matter, storm and ground
water
Catch basins are required at in
walls OF $50 to 500 feet and during
heavy storms quantities OF sand will
he washed into the sewers even with
the most carefully constructed street
inlets and although this sand is not
Of itself dangerous it may contain
organic matter. On the other hand,
it is the rain which is relied upon to
a'great extent to wash away the
accumulations formed during dry
weather.
On account of the frequent
necessity of cleaning such sewers by
hand, manholes are provided for
the purpose of giving access to the
sewers, and the minimum height al
lowable is about three feet and the
expense of construction is great OBJ.
lection and in the smaller cities the
burden OF expense Overbalances the
gain in health and comfort.
While the common combined OF
water carriage system of sewerage
conducts in one channel both rain
water and sanitary sewerage, in the
separate or divided system complete
net work of drains is provided for
the sanitary sewerage occasionally
including the ground water, while
the rain water is carried off either by
cutters or storm sewers.
In the separate system for max
imum quantities Of sanitary sewerage
pipes to 10 inches in diameter will
sa tisfy the requirments OF quite
large districts. BY the use OF t'tlush-
ing" tanks, these will run full, or
nearly SO once or twice daily and
pipes kept clean with less water than
would be used in the combined
system. 1t is usual to allow one
tank holding from 25 to 10 cubic feet
for every 200 and 500 inhabitants or
an average Of about 10 cubic feet per
capita q year.
The first city in America to be
severed on the separate system was
Memphis, Tenn, and it has given
such satisfaction that a large
number OF our cities have adopted it
and especially in those towns which
are not closely built up and the
street traffic not unusually heavy.
One district in Paris, France, has
been supplied with separate sewers.
Dayton, Ohio, with about 10000
population is so severed the city
being divided into three districts,
each with main trunk sewer into
which the latterals discharge, the
trunk sewers being each nearly two
miles in length in order to get the
proper grade. On the thickly populat-
ed and business streets a sewer is
sometimes laid on both sides of the
street
Automatic appliances are used for
flushing the sewers of the separate
system, these operate after the
manner of an intermittent spring. A
reservoir is slowly filled with water,
which is suddenly discharged into
the sewer, thus causing a flushing
wave, the amount of water and
period of flushing are SO chosen that
the sewer will run full. The reservoir
is usually fed from the water mains
through valve opened sufficiently
to give the proper quantity for
regular action. When the water
reaches a certain height a siphon is
formed by two tubes and the action
is quite rapid, q small quantity OF
water remains as seal against
sewer gas.
In Memphis the flushing tanks
hold about 400 gallons and are
cmptied every "a hours, the discharge
lasts about 40 seconds and cleans
about 1000 feet OF sewer.
In laying sewer mains the usual
practice is to provide a Y connection
for every lot, the location being
determined by the property owner
and a record Or plat of each connec-
ton is kept in the engineer's office for
references and it is usual to require
all lots which are built upon to make
connections with the sewer within a
certain time.
Special ordinances must be passed
and enforced for the proper govern
ment of sewers.
The low cost Of the separate as
compared with the combined system
has made it's adoption possible for
cities of moderate size rreat