The Indianapolis journal., 1885-08-22
LONDON SEWAGE.
What It Is Estimated To BE Worth, ans
Plans for Its Disposal Considered.
Bradstroet's Rprorts

What 1t Is Estimated To BE Worth, and
Plans for Its Disposal Considered.
Bradstreet's Reports.
1t has been computed that the annual value
OF London sewage amounts to 8s Sd per ind
vldual, and. estimating the population at 4, 600,
0OO persons, the total value would he more than
S8. 100000 per annum. 1t would thus appear on
the face Of it, that in some way or other this
sum should be saved for the city. There are two
ways of deriving profit from sewage; one is
by the application of sewage to land, as
for instance, is done in Pullman, H., OF
from treatment by chemical processes.
Precedents for the first plan exist in Great Brit
ain. the more notable ones being in Edinburo
and Doncaster: but from neither of these could
the commissioners derive sufficient encourage
ment to infer that the pumping and other ex
penses would not cancel ali Of the possible profits
Ihe second plan is regarded as Yet more unfa
V0rahly, tor the 'avalaOie material value of the
sewage is at present too small to admit of OBJ
tanning from it any product which can be sold at
anything like the cost Of its production "
with reference to the plans for the treatment
of the metropolitan sewage. four possible
schemes are presented and analyzed. These are
broad irrigation, filtration through land, process
ses CT deposition or precipitation, and preclpita
ton supplemented by application to land The
testimony seems to be quite decisive and uni
form that for every one hundred persons one
acre would be needed in broad irrigation, and
that the sewage should be strained or purified
Of the land When 1t is remembered that 40
600 acres are equal to about sixty two square
miles, the impracticabity of this scheme is APP
parent for such farming area can be found
| III the ncghborhoOd of London.
The method which meets with the greatest
favor from the commission is the last one men
toned. The chief advantage is that the sewage
is thereby much more thoroughly deprived of its
noxious qualities. The process is found il
actual use in Birmingham, and is described as
| follows The sewage Is treated with lime and
allowed 10 deposit IN series Of largo tanks; fhf
clarified liquid is then passed through porous
land, after which it runs into the river being
found perfectly innocuous. The eudge deposit
which amounts to $50 tons day is allowed tc
run IN It's semi-tuld state upon portion of the
| land laid out to receive it, after which
it is dug into the ground which is covered
with soil, planted, cropped, and used for ftra
ton. one acre per week is allotted for this
purpose, and the land so used remains for three
years before sludge is put upon it again. Thus
the quantity Of land required for the disposal OF
the sludge would be 1856 acres.n Such system
meets the chief difficulties 1t does not require
the large area demanded for broad irrigation
and it clarifies the filth which is now polluting
the Thames, even up to the bridge The
| history Of Lond0ns sewage experiment con
clusvely shows that city has not solved the
problem when it has even devised a method o1
drawing off it's drainage. The termini must be
considered, as well as the lines of transporta
ton.