San Antonio daily light. [volume] (San Antonio, Tex.) 1886-1907, 1894-07-23
emptied into it, crude

Ut is agreed among most SANTA
Try engineers, that in order to safe
ly discharge crude sewage into
stream similarly situated as is
that of the San Antonio river, the
dilutiOn or quantity of clear water
as compared with the sewage,
should be at least 20 to l, that is,
there should be at least 20 times
as much clear water as there is
sewage.
Your city engineer informs me
that the average flow of the San
Antonio river for the past five
years has been at the rate of 5000
cubic feet per minute, which is
equivalent to 54,000,O00 gallons per
twenty-four hours. This flow, would
on the basis above referred to. be
sufficient to dilute not quite 3,OOO,-
600 gallons of sewage per day.
1t is estimated that the flow of
sewage for the present population
would be about 100000 gallons
daily. To properly dilute this
quantity of sewage would, on a
basis of 20 to /, require daily
flow in the river of 100000 gall
Ions.
1t therefore appears that some
method of sewage treatment must
eventually be resorted to.
1t is estimated that works for
precipitation, together with sewers
leading to them, would cost $751;
10000 for the present population.
1t is probable that the annual cost
Of treating the sewage of 10000
people would be not less than
Sl2,0O0.O0 per annum. This sum
capitalized at SO would represent
an expenditures of $240,000.O0
which added to the $75,000.00 the
cost of the plant, amount to $315,-
10000.
If the sewage is disposed of by
irrigation it is thought that it will
have to be ultimately taken to
land as far distant from the city as
the Morrill, Poor Property, south
of the city limits. While from an
examination of this land, I am
convinced that it is admirably
adapted for sewage disposal, it is
quite probable that other land
equally suitable can be found in
this vicinity. Estimates, however,
are based of disposing of the sew
age on this property to dispose of
the sewage on this land, will re-
quire lifting it about 40 feet in
height.
1t is estimated that the outfall
sewer, together with the pumping
station, and a sufficient quantity
of land properly prepared for the
present population, will cost about
$1l0,000.00. 1t is also estimated
that the annual expense of pump
ing 100000 gallons of sewage dali
ly will be 100000. This amount
capitalized at per cent. represents
a capital of $100,000.00, which, add
ed to $ll0,00O.OO, makes $2l0,0OO.00,
the cost of irrigating as compared
with $3l5,000.O0 for precipitation
works. / therefore recommend
that the sewage be disposed of
eventually by irrigation or filtra-
ton.
1t will probably require not to
exceed one acre of land for each
200 inhabitants. would be we'll
to buy not less than 500 acres, and
to prepare only so much OF it as is
required from time to time for dis
posing of the sewage. The sizes of
the sewers as designed vary from s
inches to 81 inches interior dia-
meter.
In some cases a sewer inches in
diameter or even less,would be suf-
ficient capacity to carry the flow
reaching it, but experience has
shown that stoppages often occurin
sizes less than inches in diameter,
whereas in sewers of s inches and
over, the stOppages are compare
lively very few.
1t is intended to use vitrified pipe
for all sewers of "a inches or less in
diameter, and to build all sewers
of over "a inches in diameter, of
brick, except at river crossings
where it will be best to use wrought
iron or steel pipe coated with tar.
In order to connect the estates
with the sewers, from time to time,
branch openings are to be laid in
the sewers when they are built, so
as not to have break in them
afterwards. In the case of brick
sewers, short pieces of pipe called
"slants" are built into the brick
work on either side. In case of
pipe sewers branch openings are
used. Each method is fully
shown by the accompanying detail
drawings. The openings in these
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