Improvements in Apparatus Connected with the Treatment of Sewage.
Year: 1887

page_text: Date of Application, 18th June, 1887
Complete Left, 16th Mar., 1888
Complete Accepted, 20th Apr., 1888
PROVISIONAL SPECIFICATION.
Improvements in Apparatus Connected with the Treatment of
Sewage.
I, FREDERICK WILLIAM LACEY Civil Engineer and Surveyor 100 Windmill Road
Brentford, Middlesex, do hereby declare the nature of this invention to be as
follows:-
This Invention relates to the introduction of air into sewage and the filtration of
what is termed the effluent thereof, and in machinery for dealing with sewage sludge,
and has for its object the oxidization of sewage, and also the oxidization and clarifica-
tion of the effluent and providing for and facilitating the discharge of the liquid from
Filter Presses, and an improved method of using and re-using compressed air in
Filter Presses, and in cleansing the filtering medium of Filter Presses whilst in
position, and also other detail improvements in and connected with Filter Presses.
The Invention consists in the introduction of air into Sewage whilst it is being
pumped from one level to another, for this purpose I introduce a tap in the suction
pipes of Sewage pumps, between the pump plunger and the end of the suction pipe,
so that the air is drawn with the sewage into the pump barrel and thus thoroughly
mixed whilst passing through the pump and during its flow to the outfall, this method
would also supply air to the air vessel as required, which could be regulated with an
ordinary cock.
Where precipitation processes are employed I pass the effluent over horizontal or
inclined cloths or matting made of any fibrous material, fixed in channels or otherwise,
which are so placed that when one portion is choked the effluent may be turned in
another direction upon a second or third bed of cloths or matting, the cloths (and
channels if used) are sufficiently elevated to allow the effluent after passing through
them to fall through the atmosphere in a divided form, similar to a shower bath, the
cloths or matting may be extended to enable the flow to gradually follow along them
in a thin stream and filter with or without head of water.
Where Filter Presses are employed to treat sewage sludge I facilitate the flow of
filtered liquid by attaching flexible pipes to the outlet of each diaphragm or plate,
and the fluid is conveyed through these pipes into a larger fixed pipe or vessel which
is acted upon by a suction pump or vacuum and thus each filter cloth is relieved of

page_text: atmospheric air pressure on one side, whilst the pressure forcing the sludge is
maintained on the opposite side.
:
In order to further facilitate the extraction of the filtered liquid and to provide for
cleansing the filtering medium the diaphrams or plates are hollow and constructed
similar to an iron grate with a sheet of perforated iron on each side forming a space
or chamber between the iron sides which support the filtering medium and which are
connected with the usual outlets of the diaphrams or plates. The liquid may pass
direct from the sewage sludge into these chambers and thence to the outlets without
passing along the surface of the plates or immediately under the cloths towards the
edge of each diaphram as is done in most Filter Presses.
When the cloths become choked water or steam may be forced through them by
stopping the suction pump or closing the connection used for extracting liquid and
allowing water or steam to pass into the larger fixed pipe and through the flexible
pipes attached to the plates.
When compressed air is used to force sewage sludge into filter presses a vessel
called an air receiver is employed to store compressed air and two or more other
vessels called sludge rams are employed for holding sludge whilst being forced into
the presses and the compressed air is usually passed from the air receiver on the sludge
in one ram to be further utilized by being exhausted on the sludge in the other ram
and then blown into the atmosphere.
My improvement consists in conveying this waste compressed air back to the air
receiver by connecting the outlets or pipes from the sludge rams to the inlet valves of
the air cylinder of the compressor and thus have a compound air compressor, in other
words the air which is drawn into the compressor from the sludge rams is already
compressed and relieves the compressor equal to the pressure of air supplied.
The studs or stays in the diaphrams or plates to resist unequal strain are also made
to hold the filtering cloth by a loose washer and peg or horse shoe collar and thus
give a simple means of replacing the cloths when required.
These improvements or any portion of them may be used in circular, square, or
any form of Filter Presses.
Dated this Eighteenth day of June 1887.

page_text: Improvements in Apparatus Connected with the Treatment of
Sewage.
I, FREDERICK WILLIAM LACEY Civil Engineer and Surveyor 100 Windmill Road
Brentford, Middlesex, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement:—
This Invention relates to the introduction of air into sewage and the filtration of
what is termed the effluent thereof, and in machinery for dealing with sewage sludge,
and has for its object the oxidization of sewage, and also the oxidization and clarifica-
tion of the effluent and providing for and facilitating the discharge of the liquid from
Filter Presses, and an improved method of using and re-using compressed air in
Filter Presses, and in cleansing the filtering medium of Filter Presses whilst in position,
and also other detail improvements in and connected with Filter Presses.
The Invention consists in the introduction of air into sewage whilst it is being
pumped from one level to another, for this purpose I introduce a tap in the suction
pipes of sewage pumps, between the pump plunger and the end of the suction pipe
so that the air is drawn with the sewage into the pump barrel and thus thoroughly
mixed whilst passing through the pump and during its flow to the outfall, this method
would also supply air to the air vessel as required, which could be regulated with an
ordinary cock. I have not thought it necessary to show this arrangement in the
drawings as it will be readily understood, and as the position varies according to
the arrangement of suction pipes to the sewage pumps.
Where precipitation processes are employed I pass the effluent over horizontal or
inclined cloths or matting made of any fibrous material, fixed in channels or otherwise,
which are so placed that when one portion is choked the effluent may be turned in
another direction upon a second or third bed of cloths or inatting, the cloths (and
channels if used) are sufficiently elevated to allow the effluent after passing through
them to fall through the atmosphere in a divided form, similar to a shower bath, the
cloths or matting may be extended to enable the flow to gradually follow along them
in a thin stream and filter with or without head of water.
In order that this part of my invention may be readily understood I will now
describe it with reference to the accompanying drawings-Figure I represents a
longitudinal section on A. B. (Figure II) of the cloths (or matting) and channels
supported at one end near the precipitation tank a so that the effluent may flow direct
upon the fibrous material, the cloths may however be placed at any distance from the
tanks to suit circumstances. Figure 11 represents a plan of the channels b and
filtering cloths in connection with a trough c common to the precipitation tanks a
and sluice gates are provided at d, when opened they allow the effluent water to pass
s indicated by arrows. Figure III represents a cross section on line C. D.

page_text: (Figure 1) through the channels o, shewing the cloths or matting supported on iron
gratings.
Where the continuous flow of effluent is adopted I prefer to erect the channels a
little lower than the end wall of the precipitation tanks as shewn at e on Figure I,
and where floating arms are employed the channels may be adjusted to suit the level
of the outlet. The channels may be inclined slightly to allow the flow of effluent
over a large surface and they are fixed at a distance from the ground on suitable
standards to allow the drops of water, as passed through the cloths or matting, to be
acted upon by the atmosphere as shewn at f. When the cloths are not in use they
themselves also have a good chance of being acted upon by the atmosphere. Channels
are provided at g to carry the effluent away, and these may be constructed at a suitable
level to pass the filtered effluent either upon land for further treatment or direct into
a stream, by this means the effluent is clarified by filtration through the cloths or
matting and better oxidized by the action of the atmosphere whilst on the surface of
the cloths and in passing through the air in a divided form over a paved surface to
the channel.
Where filter presses are employed to treat sewage sludge I facilitate the flow of
filtered liquid by attaching flexible pipes to the outlet of each diaphram or plate, and
the fluid is conveyed through these pipes into a larger fixed pipe or vessel which is
acted upon by a suction pump or vacuum and thus each filter cloth is relieved of
atmospheric air pressure on one side, whilst the pressure forcing the sludge is
maintained on the opposite side.
I represent this part of my invention on the accompanying drawings, Sheet 2;
Figure IIII represents a side clevation of a filter press with flexible pipes and large
fixed pipe attached. Figure V represents a plan of the same, h represents the filter
press, the flexible pipes and j the larger fixed pipe. The flexible pipes may be made
of india rubber or other flexible substance and attached to the outlet of each press
plate by means of a screwed nozzle joint and secured to the larger pipe by a similar
contrivance, they are cut longer than the actual distance between the press plates and
large pipe, to allow the plates to be moved when discharging a press of sludge cake
without disturbing the nozzle joints. k represents a vacuum vessel which is in direct
communication with a vacuum pump and is also connected with the large pipe j and
at a valve is placed to shut off the connection when necessary, I also place a larger
cock m in the large pipe j to allow the fluid to pass away without being acted upon
by vacuum, as the action produced by vacuum is the most serviceable a short time
after the press has been charged, the cock n is also necessary when cleaning the
cloths.
The communication between the press plates and vacuum may be made by holes
through the bottom or corner of the plates and continued through the end standard
of the press where connection is made, or other mechanical means may be used to
obtain similar results. The pressure of air employed to force sewage sludge into
filter presses varies, as does also the pressure exerted by sludge pumps when used for
this purpose, but in either case it is obvious that whatever pressure is maintained on
the sludge whilst forcing, its action is facilitated by relieving the atmosphere on the
other side of the filtering cloth by vacuum, and thus that pressure may be propor-
tionately reduced. It is also obvious that if the presses are placed at a low level to
obtain a head, sewage sludge may be pressed without the aid of compressed air or
force pumps.
In order to further facilitate the extraction of the filtered liquid and to provide for
cleansing the filtering medium, the diaphrams or plates are hollow and constructed
similar to an iron grate, with a sheet of perforated iron on each side forming a space
or chamber between the iron sides which support the filtering medium, and which are
connected with the usual outlets of the diaphrams or plates. The liquid may pass
direct from the sewage sludge into these chambers and thence to the outlets without
passing along the surface of the plates or immediately under the cloths towards the
edge of each diaphram as is done in most filter presses.
I represent this part of my invention on the accompanying drawings, Sheet 3.

page_text: Figure VI represents an elevation of one of the diaphrams or press plates, o is part
of the perforated iron plate attached by screws, or other suitable means, to the
diaphram.
is the
Figure VII represents a section of a diaphram or press plate on line E. F.
space formed between the two perforated plates (also shewn on Figures X and XII
on same sheet) and q small holes connecting the spaces with the larger hole at the
bottom of the diaphram to allow the liquid to flow to the outlet into the flexible pipe i,
shewn on Figure VI. rare iron bars or ribs forming a support to the perforated
plates and to resist pressure when in action. When round diaphrams are used the
outlet hole is made at the lowest point of the circle and is in connection with the
spaces by apertures at the bottom of each rib.
When the cloths become choked, water or steam may be forced through them by
stopping the vacuum pump or closing the valve 1, shewn on Figure IV, and allowing
water or steam to pass through valve n into the larger pipe j and through the flexible
pipes attached to the diaphrams or plates, thus the filtering medium may be cleansed
without the trouble of taking them off the diaphrams.
When compressed air is used to force sewage sludge into filter presses a vessel
called an air receiver is employed to store compressed air and two or more other
vessels called sludge rams are employed for holding sludge whilst being forced into
the presses, and the compressed air is usually passed from the air receiver on the
sludge in one ram to be further utilized by being exhausted on the sludge in the other
ram and then blown into the atmosphere.
My improvement consists in conveying this waste compressed air back to the air
receiver by connecting the outlets or pipes from the sludge rams to the inlet valves of
the air cylinder of the compressor and thus have a compound air compressor, in other
words the air which is drawn into the compressor from the sludge rams is already
compressed and relieves the compressor equal to the pressure of air supplied.
I represent this part of my invention on the accompanying drawings on Sheet 4.
Figure VIII represents an elevation and Figure IX a plan shewing the pipe con-
nections to carry out this improvement-s' and s² are the sludge rams used for storing
sludge whilst it is being forced into the Filter Presses through pipes t, and u is the
air receiver for storing compressed air connected by pipes to supply air pressure to
the sludge rams, valves w¹ and w², and 1 and 2 are for the purpose of utilizing the
compressed air. When sludge ram s¹ has discharged its contents into the presses
the compressed air is allowed to pass through valves and ² into the sludge ram s²
which has already been filled with sludge, valves w' and a and w² being closed. When
the air has been utilized or has balanced its pressure between the two rams valve ² is
closed and the remaining compressed air from sludge ram is passed into the
thus 1 use
cylinder z of the air compressor through pipes y and into air receiver Wy
the air compressor on the compound principle by obtaining compressed air from the
rams to feed it. I also provide a relief valve k¹ in the pipe y to allow the atmosphere
to enter when the pressure in the rams is reduced to nearly that of the atmosphere.
Valve is provided for blowing off into the atmosphere the compressed air remaining
in the pipes or rams, as may be necessary.
The studs or stays in the diaphrams or plates to resist unequal strain are also made
to hold the filtering cloth by a loose washer and peg, or horse shoe collar and thus
give a simple means of replacing the cloths when required.
1 represent this part of my invention on Sheet 3. Figure X is a section and
Figure XI an elevation, of part of a diaphram where the stud is placed, a' is the peg
passing through the cloths, the perforated iron plates, and the diaphram 6. the
washer and d a nut to keep the peg and washer in position. The peg is made with a
square shoulder and of a suitable length to allow the head to come in contact with
the alternate end of a peg in the next diaphram, so that when the diaphrams are in
position and a pressure is put upon them the whole set of diaphrams are stayed to
resist any pressure that may be brought to bear unequally upon any single plate.
Figure XII is a section and Figure XIII is an elevation shewing another method of
accomplishing the same end by a horse shoe collar. e' is the peg passing through

page_text: the cloths ', the perforated iron plates, and the diaphram 6', and is made eccentric
at the point f¹ to allow the horse shoe collar g¹ to fall into a recess and thus take up
the strain in the same manner as the above arrangement when the plates are under
pressure.
These improvements or any portion of them may be used in circular, square or any
form of filter presses.
Having now described and ascertained the nature of iny invention and explained
the best means I am acquainted with of performing the same, I wish it to be under-
stood that I do not restrict myself to the precise details shewn on the accompanying
drawings, but I claim as my invention:-
1. The oxidization of sewage by the admission of air into it, whilst being pumped
from one level to another.
2. The clarification of the effluent by passing through cloths and oxidization as
herein shewn and described.
3. The use of vacuum in communication with each diaphram as herein shewn and
described.
4. The use of hollow diaphrams or plates as herein shewn and described.
5. The use of steam or water for cleansing the filtering cloths as herein described.
6. The utilization of compressed air by conveying it from the ram back to the
compressor as herein shewn and described.
7. The use of pegs with washers to resist unequal pressure as herein shewn and
described.
Dated this Sixteenth day of March 1888