Process of and Apparatus for the Treatment of Waste-Matters.
Year: 1897

page_text: Date of Application, 19th Oct., 1897-Accepted, 8th Jan., 1898
COMPLETE SPECIFICATION.
Process of and Apparatus for the Treatment of Waste-Matters.
I, GEORGE BARKER, Fellow of the Chartered Institute of Patent Agents, of 77
Colmore Row, Birmingham, in the County of Warwick, Consulting Engineer,
(Communication from abroad by Ludwig Rissmuller, a citizen of Prussia, Empire
of Germany, by profession an engineer, at present residing at the Hotel Hanover,
corner of Arch Street and Twelfth Street, in the City of Philadelphia, County of
Philadelphia, State of Pennsylvania, in the United States of America), do hereby
declare the nature of this invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:
It is the object of my invention to provide a new method and new and improved
apparatus for treating city garbage animal or vegetable waste-matters, etc., for the
purpose of economically converting the same into merchantable products, separating
the greases from the waste, and converting the residuum into a fertilizer; and also
to utilize the gases evolved during treatment of the waste and, preferably, for
heating the waste and for the production of the power necessary for operating the
apparatus for handling the waste and its products, and also for operating the centri-
fugal separator used to separate the greases from the waste.
Heretofore, in the treatment of waste-matters for the purpose of extracting
greases therefrom, or for converting the waste-matters into fertilizing material, etc.,
so far as I am aware, operators have not succeeded in extracting from the waste
a sufficient proportion of the greases as that the residuum could be fairly said to
be freed from grease, except with naphtha which is expensive and disadvantageous,
the usual proportion of the greases remaining in the residuum being about fifty
per cent. of the amount contained in the waste before treatment. Consequently,
all efforts to produce a fertilizer which was practically freed from grease (a result
long desired) have failed; and the great amount of grease remaining in the ferti-
lizer is not only lost to commerce, but reduces the value of the fertilizer, as it delays
its action. True, it has sometimes been the practice to incinerate the residuum,
but this has resulted in destroying the grease, and such a degree of heat is necessary
that the ammonia will be liberated, and driven off from the ashes. Again, it has
been proposed to dry the greasy residuum, but if the greases are to be removed, the
prohibited heat must be employed.
It has been found that, when waste-matters have been boiled with water or acids
(or both together), only a portion of the greases rise to the surface, the rest remain-
ing as an emulsion in the mass. Boiled waste has heretofore been treated in
power-presses, to remove a solution containing water and greases, which was
allowed to remain in settling tanks. But this treatment has seldom resulted in
the removal of more than half of the greases from the waste. The residuum,
containing such a large proportion of greases, is dried, and, after grinding, is used
for fertilizing material. When acids have been used (alone or with water) in
boiling the waste, the mass could not be treated in the power-presses, and only
the floating greases could be separated.
My new process, broadly stated, consists in first boiling, or otherwise treating

page_text: the waste with water, or acids, or a mixture of water and acids, until the waste is
converted into a uniform fluid mass in which the structure of the waste has been
destroyed and the greases are rendered therefrom. I obtain good results when I
use a mixture of sulphuric acid and phosphoric acid. The degree of heat, length of
treatment, and proportions of acids, water and waste, may be varied to suit the kind
of material to be treated. The waste should be subjected to the action of acid
in a lead-lined vessel, for instance, somewhat like the pulp-digesters in common
use.
The waste, acid and water are boiled until converted into a uniform mass, not
unlike a thick, heavy soup, in which the original structure of the waste has been
destroyed, and the greases rendered therefrom. This results in bringing the garbage
to a condition which permits the quick and complete removal of the greases from
the mass.
In my process, the completely digested waste is led into a centrifugal-separator
of high speed. The centrifugal-separator which I have used is one having a non-
perforated bowl, and I have found that the ordinary centrifugal-separators having
perforated bowls cannot advantageously be used to separate the ingredients of a
mass according to their respective specific gravities, but can ordinarily only be used
as driers or presses. Hence, centrifugal-separators which act merely to expel water
are not available in my process. In the operation of the closed-bowl centrifugal-
separator, there is a quick and well-nigh perfect separation of the mass into its con-
stituents according to their respective specific gravities, which cannot, so far as I am
aware, be accomplished by any other means, because of the thickness of the matter
acted upon. Generally speaking, the mass will be separated into three bodies,
(1) the heavier solids, (2) the acid solution, containing also the soluble substances
which were in the waste, and (3) the greases rendered out of the waste. The solids,
being heaviest, will be driven to the wall of the separator, the acid solution will be
the next layer, and nearest the centre will be the greases. The rotary movements
of the bowl are also utilized for driving the separated greases out of the bowl,
the acid-solution and heavier ingredients being preferably removed together. The
greases may then be used for any purpose desired.
The solution and solids are then worked into fertilizing material. The mixture
may be treated with phosphate of lime, or other suitable substance acting to
neutralize or remove the free acids, the presence of which tend to render drying
difficult. The residuum is then dried, preferably in a closed-dryer, being agitated
during drying. By the presence, during the conversion of the waste, of free acids
-sulphuric, phosphoric, or muriatic acid, the phosphoric acid of the tri-basic of
lime (Rock Phosphate, etc.) will be formed in the soluble or available form, and the
potash as soluble potash, as by the treatment of the waste with either sulphuric or
phosphoric acid, the phosphoric acid which was contained in the waste before
conversion, is freed therefrom during treatment by my process, and can stand the
high temperature required; in addition, the potash which was present in the form
of insoluble silicate, is, by the presence of the free phosphoric acid, transformed
into a soluble salt.
In view of the fact that the heavier ingredients rejected by the centrifugal-
separator are practically free of greases, it is not necessary, in drying, to employ a
degree of heat which will deleteriously affect the ammonia.
The dried product is ground, and can be more advantageously used for fertilizing,
than fertilizing material produced from waste by other processes, in view of the
fact that it is freed from grease (which is objectionable in that it delays the action
of the fertilizer), and contains ammonia in an available form. .
In the accompanying drawing, there is shown a new combination of apparatus
useful in the treatment of waste-matters according to my process.
In the accompanying drawings, 1 indicates a pit into which the garbage (or other
waste animal or vegetable matter) is dumped. The garbage is then fed on to the
endless travelling conveyor, 2, which passes around pulleys, 3 and 4, and the
garbage is deflected by a plate, 100, into the digester, 5, through the manhole, 6,

page_text: '
thereof. When the digester has been filled, or nearly so, the operation of the
conveyor is stopped, or the feeding of garbage thereto is discontinued. Any other
suitable form of conveyor may be employed, or, if preferred, the garbage may be
transferred directly into the digester, 5.
A sufficient quantity of garbage having been passed into the digester, the man-
hole, 6, is closed, and steam is forced through pipes, 7 and 8, into the digester.
In most cases, it will be found necessary to add sulphuric acid to the mass in the
digester, and the interior of the digester is lined with lead, or other material
capable of resisting acids. The boiling of the garbage is continued until the
structure of the garbage has been destroyed and the greases rendered therefrom,
and the whole converted into a soupy liquid, uniform throughout. This brings
the greases to a state which enables their complete separation from the non-greasy
ingredients.
During the boiling of the garbage, the lightly-volatile ingredients are evaporated
from the garbage, due to the heating of the garbage with or without the use of
sulphuric acid, and vapors and gases are are also evolved. In order to
carry the vapors and gases off, I provide a pipe, 9, leading out of the
top of the digester and terminating in a condenser, 10. The condenser is pre-
vided with a pipe, 11, for carrying off the distilled water and may lead to a sewer
or other point. The gases, separated from the vapors, are led from the condenser
by a pipe, 12, into the lower end of a gas-producer, 13. This gas-producer con-
tains a body, 14, of burning coals, or other heating and gas-producing material,
or other heating structure. The gases pass upwardly through the heated material,
and this results in heating the gases to a point where, in combination with the
producer gas, they may readily be used for fuel purposes.
The heated gases are led, by pipe 15, from the heater, 13, and into the regener-
ating chambers, 17, 17, of furnace of the steam generator, 16, and pass up into the
combustion-chamber, 18.
By my invention, therefore, the obnoxious vapors and gases are led out of the
digester, the vapors are separated from the gases, and the gases are utilized for
fuel purposes. The steam made in boiler 16 may be used to supply the digester,
or to turn the machinery of the plant, or for other purposes.
The connections between the digester and condenser, between the condenser and
heater, and between the heater and the furnace, may be quite different from the
forms or arrangements illustrated in the accompanying drawings.
Recurring to the digester, 5, when the garbage therein has been sufficiently
digested, a valve,, 20 (in a neck, 19, at the lower end of the digester) is opened.
This allows the digested garbage to fill a measuring-chamber, 22, comprising a
hollow chamber commencing underneath the neck, 19, and terminating at valve, 24,
in the delivery-neck, 25. Within the measuring-chamber, and running lengthwise
thereof, there is an endless screw, 23, which may be operated by turning the
handle, 21. By means of this screw, the feeding of digested garbage may be con-
trolled when the valve 24 is opened. In practice, the inlet-valve 20 is opened
until the measuring-chamber 22 is filled, and then said valve is closed. After this,
outlet-valve 24 is opened, and the digested garbage discharged from the measuring-
chamber, and into the apparatus for separating the greases therefrom.
Instead of the measuring-chamber shown, any other suitable form may be
employed. The same is true of the screw 23.
The particular form of centrifugal-separator which I prefer to employ is that
described and shown in a pending Application for Letters Patent of Great Britain
and Ireland, No. 24084 of 1897, for Centrifugal Separators, to which I refer for a
more detailed description than is herein given.
In general, it consists of a bowl comprising an upper bowl-section, 26, and a lower
bowl-section, 27, a pulley 28, a sleeve, 29, driven by the pulley, and a hand-lever, 30,
and connections for lifting the upper section, 26, away from the lower section,
whereby a continuous peripheral discharge-port is formed.
The sections of the bowl having been brought tightly together, the valve 24, of

page_text: the measuring-chamber is opened, and a quantity of digested matter is discharged
(assisted by the screw 23) into the rotating-bowl of the centrifugal-separator.
Within the bowl, the ingredients of the digested garbage are separated according
to their respective specific gravities, being generally divided into three concentric
rings, and first comprising the freed and purified greases, the second containing
the acids and substances dissolved thereby, and the third comprising the non-
greasy heavy solid ingredients. The greases are spun out through pipes, 31, 31,
and are caught by the fixed ring-like pan, 32, surrounding, but out of contact with,
the upper bowl-section. By means of a pipe, 33, the greases are led from said pan
into any suitable receptacle.
When the greases have been separated from the mass within the bowl, the work-
man lifts the lever, 30, and with it a shaft within the sleeve, 29. The upper
bowl-section, 26, is secured to the upper end of said shaft, and is, therefore, lifted
away from the lower section, 27, of the bowl. The continued rotary movement of
the bowl results in the complete expulsion of all the heavy and acidulated
ingredients from the bowl, and the sections are then brought together ready for
treating another quantity of digested garbage. The substances expelled from the
bowl strike against the inner surface of a mantle, 34, which encircles the bowl,
and extends above the point of separation of the bowl-sections. Said mantle
terminates in a delivery-port, 35, whereby all the substances expelled by the bowl
are brought to the same point.
My method for separation of greases from digested garbage may, however, be
practiced with other forms of centrifugal-separators than that herein shown and
described. For instance, instead of the split-bowl centrifuge controlled by a lever,
a split-bowl centrifuge which automatically opens at certain pressures of the
heavier ingredients, may be employed; or, if desired, any other suitable form of
centrifugal-separator may be used.
The non-greasy ingredients fall into a dryer, 37, through a manhole, 36, being
treated (either before or after being discharged into the dryer) with some substance
which neutralizes the free acids. The dryer having been filled (or nearly so), the
manhole is closed, and the dryer is heated. During the drying operation, the con-
tents of the dryer are kept in motion by stirrers carried by a shaft, 38, driven by
a pulley, 39. This keeps the material in a granular condition, and hastens the
drying of the same. The gases and vapors evolved in the closed dryer are carried
off by a pipe, 40, and are led into a condenser, 41, wherein the steam is condensed,
and the water of condensation is led out through a pipe, 42. The separated gases
are carried by a pipe 43, into a vacuum-pump, 44, and from thence, by a pipe 45
to the gas-heater 13, hereinbefore referred to.
The dryer is heated by means of steam introduced through pipes, 46 and 47,
and this steam may be taken from the boiler, 16, or other point.
When the contents of the dryer are considered sufficiently dry, a manhole, 48,
in the bottom of the dryer, is opened, and the dried material, now ready for use
as a fertilizer, is conveyed by a belt, 49, passing around pulleys, 50 and 51, to a
second conveyor, 52, passing around pulleys, 53 and 54. The last-named con-
veyor delivers the dried ingredients on to a revolving-screen, 55, the smaller
portions passing between the meshes of said screen, and the larger portions rolling
or passing over the screen into a grinder or crusher, 56. After grinding, the tail-
ings may be thrown upon the conveyor, 52, for re-screening, and, if necessary,
re-grinding.
While I have shown two conveyors for transferring the dried material to the
screen, either or both of them may be dispensed with.
I do not herein claim the construction of centrifugal-separator hereinbefore
described, the same being fully described and shown, and the novel feature thereof
claimed, in a pending Application, No. 24084 of 1897, for Letters Patent of Great
Britain and Ireland.

page_text: Having now particularly described the nature of my said invention, and in what
manner the same is to be performed, I declare that what I claim is:-
1. The process of treating waste-matters, consisting in, first, boiling the waste
until it is converted into a uniform mass, in which the structure of the waste
has been destroyed and the greases rendered therefrom, and, second, separating the
ingredients of said mass by centrifugal action according to their respective specific
gravities, and removing substantially all of the greases from the mass.
2. The process of treating waste-matters, consisting in, first, boiling the waste
with acid until it is converted into a uniform mass, in which the structure of the
waste has been destroyed and the greases rendered therefrom, and, second, separat-
ing the ingredients of said mass by centrifugal action according to their respective
specific gravities, and removing substantially all of the greases from the mass.
3. The process of treating waste-matters, consisting in, first, boiling the waste
until it is converted into a uniform mass, in which the structure of the waste
has been destroyed and the greases rendered therefrom, second, separating the in-
gredients of the mass by centrifugal action according to their respective specific
gravities, and removing substantially all of the greases from the mass, and, third,
drying the residue, whereby a dry, grease-freed fertilizer is produced.
4. The unitary method of inoffensively treating waste-matters and economically
converting the same into merchantable products, which consists in subjecting the
same to the following steps: boiling the waste with acid in a digester until the
structure of the waste is destroyed and the greases rendered therefrom, conveying
the gases evolved to a furnace, raising the heat of said gases to a temperature
rendering them suitable for combustion, utilizing said gases as fuel and thereby
rendering them inoffensive, subjecting the digested wastes to centrifugal action to
remove greases therefrom, and drying the residue, substantially as and for the
purpose described.
5. The unitary method of inoffensively treating waste-matters and economically
converting the same into merchantable products, which consists in subjecting the
same to treatment by the power and heat generated from fuel supplied by the
gases evolved thereby, such treatment consisting in boiling the waste with acid
in a digester until the structure of the waste is destroyed, and the greases rendered
therefrom, conveying the gases evolved to a furnace, rasing the heat of the gases
to a temperature rendering them suitable for combustion, utilizing said gases as
fuel and thereby rendering them inoffensive, subjecting the digested waste to
centrifugal action to remove greases therefrom, and drying the grease-freed sub-
stances, substantially as and for the purpose described.
6. In a plant for treating waste-matters, a closed digester for treating the waste-
matters, a measuring-chamber in open connection with the discharge-port of the
digester, the said measuring-chamber having an inlet-port and valve and an outlet-
port and valve, and a device for regulating the discharge, substantially as and for
the purpose described.
7. In a plant for treating waste-matters, a digester for receiving and digesting
waste, means for discharging definite quantities of waste from the digester, a
centrifugal separator adapted to receive the successive quantities of digested waste,
and to separate the ingredients of each according to their respective specific
gravities, means for continuously operating the centrifugal separator, means for
removing the greases separated by the centrifugal separator and means for dis-
charging the non-greasy residuum therefrom, substantially as and for the purpose
described.
8. In a plant for treating waste-matters, a closed digester, a measuring chamber
in open connection with the discharge-port of the digester, the said measuring
chamber having inlet and outlet valves, whereby definite quantities of digested
waste will be delivered, as desired, and a grease separator adapted to receive the
successive quantities of digested waste and to separate the greases therefrom, sub-
stantially as and for the purpose described.
9. In a plant for treating waste-matters, a dryer for drying and granulating

page_text: digested waste, a screen for receiving the dried material, means for grinding the
coarser portions which have passed over the screen, and a conveyor for returning
the ground material to the screen, substantially as and for the purpose described.
10. In a plant for treating waste-matters, a steam-generator, pipe-connections
therefrom to a waste-digester, pipe-connections for leading away the gases and
vapors evolved in the digester, a condenser for condensing the vapors, pipe-con-
nections for leading the gases from the condenser to a gas-heater, and pipe-
connections from the gas-heater to the furnace of the steam-generator, substantially
as and for the purpose described.
11. In a plant for treating waste-matters, a closed waste-digester, a centrifugal-
separator arranged to receive the waste discharged from the digester and to separate
greases from the waste, a steam-generator, heating-connections from the steam-
generator to the digester, and pipe-connections from the digester to the furnace
of the steam-generator, whereby the gases evolved during the digesting operation
are utilized for heating the steam-generator, substantially as and for the purpose
described.
12. A new fertilizer, being the dried waste-residuum having ammonia in an
available form and substantially freed from grease.