Improvements in the Treatment of Sewage for the Purification. thereof and, the Production of Valuable Products therefrom.
Year: 1889

page_text: Improvements in the Treatment of Sewage for the Purification.
thereof and, the Production of Valuable Products therefrom.
I. CRESACRE GEORGE MOOR, of Christ Church College, Oxford, Undergraduate,
do hereby, declare the nature of this invention to be as follows:-
My Invention relates to the purification of sewage waters and the production of
valuable products therefrom
As the substances of manurial value contained in sewage are ordinarily diluted with
a great volume of water and cellulose (woody fibre) it is essential to separate-them-
out and present them for commercial purposes, in a concentrated form.
"
This is the object of my process to accomplish so,far as relates only to the matters
in-mechanical suspension..
The first part of the process of my invention comprises the following steps: The
sewage waters are fist passed through stramers in order to strain out gross suspended'
matters and then into settling and filtering tanks wherein the sewage is passed through"
a medium, namely carbonized sludge, obtained in another part of the process, the
deposited sludge being then pressed into cakes which are treated as hereafter described."
The filtrate from the settling and filtering tanks is then, aerated and purified by tlie
action, of a dash wheel contaming carbonized sludge and into, which, air is forced, and
is then. filtered through a bed of carbonized sludge wherem all the fine particles of
sludge and carbon are retained, the effluent water being then sufficiently pure to be
un into rivers
r
The second pail of the process relates to the carbonization of the sludge ‘and
production of useful products therefrom
i
'16
the
some
The sludge, akes, obtamed, as above described, mixed, if desired with
carbonized sludge which has been used for, filtering, are dried by heal which may be
economically obtained, from the combustion of gas produced in the next step of the
process
The dried rakes are placed in a distilling and calcining furnace which may resemble
a blast furnace, and ignited The distillation of the cakes yields inflammable gases,
tary matter, and ammonia. liquor, and the distilling chamber is in connection with
suitable.condensers and exhausters as in, gas works The gas may be stored and used'
for diving the cakes as above mentioned or for other heating purposes: the tarry:
matters may be distilled for oils or burnt for heating purposes; whilst the ammonia
liquo may be treated as at gas, works
The ash esulting from the calcination will contain all the phosphates and potash
originally contained, in the solid and suspended portions of, the sewage, and this ash
is to be mixed with the ammonia fixed as sulphate, for use as manure
The furnace, is provided with. means whereby part of the sludge may be with-'
drawn after carbonization, but before, being reduced to ash. for use, as the filtering
medium above referred, to
Dadow of T... 1880
1
.5
Improvements in the Treatment of Sewage for the Purification
thereof and the Production of Valuable Products therefrom.
3
----
I CarsACRT GORGE MOOR, of Christ Church College, Oxford, Undergraduate,'
do hereby declare the nature of this invention and in what manner the same is to be
[Price 6d.]

page_text: performed, to be particularly described, and ascertained in and by the following
statement:-
My Invention relates to the treatment of sewage for the purification thereof and
the production therefiom of a marketable manure consisting essentially of phosphates
and ammonia
.
I have hereinafter described my process in its entirety, but, for convenience of
description, it may be divided into two stages whereof so much of the first stage as
relates to the agent used for the precipitation of the matters in suspension forms-the
subject of a later application for Letters Patent dated the 24th day of April 1890
No 6245
The two stages which constitute the entire process are as follows:
1 The precipitation of the matters in suspension in the form of sludge and the
purification of the effluent water
2 The distillation, carbonization, and alcination, of the sludge.
It is an essential object of this process to avoid the addition of anything to the
sewage which cannot be afterwards eliminated from the sludge or which will not
add to its fertilising properties by increasing the proportion of phosphoric acid or
of ammonia contained therein For this and also for economical reasons, I use as
the precipitating agent a portion of the sewage sludge itself, after carbonization in
the second stage of the process, the carbonized sludge being for this purpose mixed
with sulphate of magnesia
In carrying out the operation, the sewage may be first passed through strainers,
to remove gross sold matters in suspension other than sewage, and then run into
settling tanks, where the precipitating agent, consisting of carbonized sludge and
sulphate of magnesia, is added
The sludge is then allowed to settle and the precipitate will contain ammonio-
magnesium phosphate After precipitation, the supernatant water is decanted off
and passed through a filter bed which for economical reasons,I make of the carbonised
sludge, obtained as hereafter described in the second stage of the process, whereby
the water is both filtered and disinfected or purified, the effluent from the filter bed
being sufficiently innoxious to be 100 into rivers without injury to fish
The second stage of the process relates to the distillation, carbonization, and
calcination, of the sludge precipitated in the first operation, and that left upon the
filter bed by the effluent water For this purpose the sludge is first dried until
it contains only about 25% of water This may be done either by pumping it
onto another porous filter bed (made preferably of carbonized sludge) and allowing
it to drain and dry in the air, or by pressing it m a filter press (the effluent in
either case being added to the raw sewage running into the precipitating tank)
and the dried sludge cut or pressed into blocks, being then charged into a furnace
somewhat resembling a blast furnace or a lime kiln, and provided with a forced
draught The furnace would have a grating near the bottom and be provided
with facilities for the removal from below the grating of the ash resulting from
the calmation of the sludge and for the removal from above the grating of part
of the carbonized sludge before calcination The upper part of the furnace is in
communication with a condensing apparatus where the ammonia and tarry matters
distilled off from the charge are collected The charge lying upon the grating
having been ignited, a forced draught is mamtained through the furnace either by
a blast of air introduced below the grating or by an exhauster in connection with
the condenser In this furnace the distillation of the charge of sludge is effected
by the heat developed by the combustion of the previously charged sludge at the
lower part of the furnace, the operation, which is conducted much in the same
way as that of lime burning being carried on continuously by introducing a fresh
charge at top as often as required and removing the ash at the bottom and also
withdrawing a part of the carbonized, but unconsumed, sludge, for filtering purposes,
as above mentioned
A suitable condenser for collecting the ammonia and tarry matters would be a range
of iron mines running around the building in which the blocks of sludge are dried or

page_text: gas
which passes
stored in wei weather so that the heat abstracted from the condensable matters
distilled off from the sludge may be utilised for drying purposes.
In some cases, the distillation of the charge yields a combustible
off uncondensed and may be used for heating purposes on the works.
By the above described distillation and calcination all organic matters and water
have been removed and the manurial constituents of the sludge have been concen-
trated without loss, for if the weight of the ash he, say, one-fourth that of the sludge
from which it was obtained it will contain four times as much phosphoric acid and
potash salts as were contained in an equal weight of sludge. The nitrogen which was
contained in the sludge in an insoluble state has now been converted into ammonia
which, being soluble, is readily assimilated by plants The ash will now consist
mainly of silica (10ad sand) and Calcium phosphate, together with.in smaller quantities,
oxide of non, alumina, magnesia, soda, and potash salts. As regards the potash
salts, it is well known that the greater proportion of the potash salts in sewage are
already in solution and cannot be arrested by any precipitant; a certain amount of
potash is, however, contarned by vegetable matters in suspension, and this will be
obtained in a serviceable form in the ash
The ash is then mixed with sulphate of ammoma obtained by treating the ammonia
quor in the manner ordinarily practised in gas works
The accompanying drawings illustrate, i central vertical section, the form of
furnace which I prefer to employ The furnace A has a charging mouth 3 closed_by
|a counterbalanced cone, and an outlet C, for the gases, leading to the condenser. The
furnace has a manhole and door D just above a revolving grating E formed of loose
bars ing ma ring-fame F supported on rollers and toothed to engage with a
pinion G turned by an outside handle Below the gating is a blast inlet H fitted
with a valve The ash pit is hopper-shaped and closed at bottom by a sliding door I
worked by a screw for withdrawing the ash
Having now particularly described and ascertained the nature of the said inven-
That what I
tion and what manner the same is to be performed. I declare
cam -
1 The herem described process of treating sewage, for obtaining a marketable
manure therefrom, which consists in the series of operations or steps above mentioned,
portion of
namely, separation of the sludge from the liquid Sewage, elimination of a
the moisture from the sludge, distillation,carbonization, and calcination, of the sludge,
and finally mixing the ash, resulting from the calcination, with the ammonia (fixed as
sulphate) resulting from the distillation, substantially as specified.
2 In the here-described process of treating sewage, the operation of distilling,
carbonizing, and calming, blocks of partially dued sewage sludge, m a furnace, by
the heat developed by the combustion of the sludge itself under the action of a forced
draught, substantially as specified -
3 In the herem-described process of treating sewage, the manufacture of a pre-
capitating, filtering, and purifying medium for sewage by carbonising blocks of sludge
under the action of a forced diaught in a furnace as specified
4 In the here-described process of treating sewage, the treatment of the ash
(resulting from the calcination of the sewage sludge in the second stage of the
operation) by mixing it with the ammonia (fixed as sulphate) resulting from the
distillation, as described