The Sun.
London, England, 1855-01-11 00:00:00

SEWERS.

" Tite-hill, Egliam, Surrey, Oct. 23, 1851.
" Gentlemen,—ln accordance with your request, as
stated by your secretary, in his letter received the 18th
inst., I have the honour to lay before you my plan, sec-
tions, estimates, and suggestions in respect of the portion
of the intercepting drainage of the metropolis called the
' Northern Drainage.'
" In forming a plan for intercepting the sewage of that
portion of the metropolis situate on the north side of the
river Thames, the following considerations appear desir-
able :

"1. As to an ultimate use of the sewage for irrigation ;
or by obtaining the solid portion for manure. Then, if
neither of these desirable objects could at present be at-
tained, at what point below London the sewage might be
discharged, with a reasonable hope of its not affecting that
portion of the river passing through the metropolis. The
place chosen.is the river Reding, at Barking-creek.
" The next consideration was to form the sewers on such
a level as would, by gravitation, pass off as much of the
sewage as could so,pass, in order to save, as much as pos-
sible, the pumping up of the sewage—a process that must
entail a perpetuarexpense.
" After trying various lines, I have selected those marked
upon the accompanying plans and sections. Then, as it
might be found far several reasons desirable to complete
the intercepting lines as far as the river Lea, before con-
tinuing the line any further east, and as the sewage enter-
ing the Lea near- Sir George Duckett's canal might be
complained of, it would be desirable to point out in what
manner, at the least extra cost, the existing sewers might
be connected, so as to deliver the sewage at Bow-creek,
until sewage manure works could be formed, or the line
carried forward to Barking-creek.
" With respect to this, a model is in preparation and
nearly complete, showing what can be done ; and, as it is
ieeen,leel to exemplify other matters connected with the
main drainage, I shall feel pleasure -le, eh wine it to you
for your information.
" Anoth3r matter for consideration was that, as the pas-
sage of the foul sewage into the Serpentine has always been
objectionable, it will be well to provide entirely for freeing
that water from such pollution. The outlet sewer across
Hyde-park, hereafter described, would effect this as well
as relieve the Ranelagh sewer.
" With respect to using the water for irrigation, there
are portions of meadow land nround ih) metropolis which
might be irrigated by the sewage water without having re-
course to pumping. Although there is no doubt as to the
value of sewage water for irrigation, yet the use and benefit
of it are not generally so well understood as toinducepereons
to make an outlay on that account ; and when the time
arrives (as I doubt not it will) when the sewage of overt'
town and place will he eagerly sought after, it will be requi-
site for some Legislative enactment to be made to felici-
tate the passage through lands intervening between the
source of supply and the locality the owner of which may
desire to use the liquid manure. My opinion is that,
although but a portion of the sewage of the metropolis
could be applied in irrigation, yet that such portion would
ultimately produce a considerable revenue.
" As to solid manure there are several methods pro-
posed for collecting the solid portion of the sewage. Each
has its merits, and although, in regard to the solid portion
of the sewage, there is a greater apathy on the part of the
public generally than towards its use by irrigation, and,
although it will take some. time to give it a full trial on
different lands,. yet that its collection will ultimately re-
munerate those engaged in the matter I do not in the least
doubt.

" In the case of the metropolitan sewage, as parties ap•
pear anxious to speculate in collecting the solid, it would
be well, before you carry any intercepting sewer beyond
the Lea, if you, as conservators for the public, should ask
such parties on what terms and in what manner they would
engage to manufacture the sewage of the metropolis (or any
portion thereof), and at what thee they would propose to
make ample payment to the commissioners for the use of
the sewage.
"When the late Mr. Forster was preparing his plan for
intercepting the sewage, I procured for him au offer for
purifying the sewage at the Isle of Dogs, and I think it
probable that the same person would renew the offer at
this time, if communicated with. This locality is emi-
nently suitable for collecting the solid manure ; a great
portion of the surface drainage can readily be kept sepa-
rate from the house drainage ; and I consider that, if the
commissioners do not agree to any offer that may be made,
they should themselves cause works to be formed, and ar-
range with some owner or owners of land to give the solid
manure a fair trial, which proceeding would prove a great
boon to the country as well as to the metropolis, as the
proceedings of the metropolis, on many points, are looked
at as an authority for similar things being done in provin-
cial places.
" When Mr. Forster received directions to prepare his
plan for the northern drainage, he wrote to me to ask as to
the fall of rain on the several days in a year. I sent him
the result for a year in which more than an average fall
of rain had taken place. This was as follows :—Of the
rainy days (there were 30 in which a quarter of an inch
fell ; 10 in which half an inch fell ; '2 in which three-
quarters of an inch fell; and 2 in which ono inch fell.
It was decided to provide for passing what would come
from a quarter of an inch in 24 hours, or 0.63 per acre per
minute, and to allow flood water from greater falls to pass
to the river.
" With regard to the sewage water, I have noticed 'in
many sewers the run of water in day and night, and in
one instance I noticed, on a locality where there were
about 31,000 inhabitants to the square mile, and found
that the run of water in the sewer was about 2D gallons per
day to each individual ; and having noticed for a length of
time the irregularity with which this passed to the sewers,
I decided upon providing sewage capacity for rather more
than that quantity in addition to the capacity required
for the quarter of an inch of rain ; being together one
cubic acre per minute."