Improvements in the Purification of Sewage and Polluted Water, and in Apparatus therefor.
Year: 1897

page_text: Date of Application, 15th Feb., 1897
Complete Specification Left, 15th Nov., 1897-Accepted, 15th Feb., 1898
Improvements in the Purification of Sewage and Polluted Water, and
in Apparatus therefor.
I, FRANK PULLEN CANDY, of Ivy Bank, Ashley Road, Bowdon, in the County
of Cheshire, Sanitary Engineer, do hereby declare the nature of this invention
to be as follows:-
The first head of my invention relates to improvements in precipitation tanks,
and the second head of my invention relates to improvements in filters; and in
apparatus therefor.
The sewage or polluted water I will speak of as sewage.
Referring to the first head of my invention which specially deals with upward
flow precipitation tanks I divide the said tank vertically or thereabouts into two
or more chambers or compartments, preferably more than two, by means of
divisions or walls which do not extend down to the bottom of the tank and pre-
ferably extend above the water level of the tank each said division (unless used
for inlet of the sewage) being provided with one or more effluent take off troughs
or conduits to convey away the treated sewage so that by means of this said con-
struction a more even flow of sewage upwards through the tank is obtained; the
tendency of the sewage in the ordinary upward flow tank being to flow more or
less in lines and not to have an uniform bodily rise, which said tendency militates
against the best results being obtained. The space between the bottom of the said
divisions or walls and the floor of the tank may serve as a common sewage feed
and as a common place of deposit for the sludge.
As a modification of this construction I may form each said chamber or compart
ment practically as a separate tank provided with its own sewage inlet and effluent
take off conduit or conduits and sludge removal arrangement the whole being
that each said cham-
within one tank, arrangements being provided so
ber or compartment (when they are being filled) may fill evenly or practi-
cally so whereby the aforesaid divisions or walls having to bear no or little strain
may be constructed very cheaply.
A further modification consists in constructing, within the tank and parallel
or thereabouts with the sides of the tank, a wall or walls which do not extend down
to the bottom of the tank so that the sewage entering between these two walls or
sets of walls shall flow down towards the bottom of the tank and then have to rise
up within the said inner walls before it can escape by means of the effluent take off
conduits which are situated therein.
A further part of this head of my invention relates to improvements in the re-
moval of sludge from precipitation tanks circular at the bottom and consists in
constructing at the centre of the tank a mound tapering upwards, such for instance
as a cone, the sludge will settle to the channel between the bottom of the said
mound and the sides of the tank and I remove it therefrom by means of a pipe
which may have the mouth thereof flattened out or have at the end another pipe
with perforations or a slot therein, the said pipe being arranged and connected

page_text: in a manner similar to that described in Letters Patent No. 17335 of 1893, granted
to me, with reference to apparatus for a circular tank.
Referring to the second head of my invention I provide two or more filters
situated the one at a lower level than the other and arranged so that the sewage
is first let into the highest filter and after the same is full the sewage is turned
off therefrom, the sewage in the highest filter is, then, or after a period of rest,
allowed to run into the next highest filter and so on, meanwhile as soon as the
highest filter is empty or after a period of rest it is again filled with sewage which
passes in a similar manner down through the other filter or filters so that the
filters successively undergo a series of charges of sewage and rests or aerations.
I prefer the flow of sewage through these filters to be horizontal or lateral;
mechanical arrangements are provided whereby the flow of sewage is caused to
open and close the necessary valves or ports so that the cycles of work and rest
as before described shall be automatically controlled and worked.
It will be evident that when the sewage is automatically turned off from the
highest filter it must be either stored or turned automatically into another set of
similar filters and automatically back again in due course into the first highest
filter and so on.
As a modification I may store the sewage for a time and then let it automatically
and suddenly through such a series of filters so that the cycles of rest and work
are obtained; the filters are preferably very shallow ones, say three inches deep,
and work on the lateral flow. I may not only store the sewage and send it sud-
denly through the highest filter but may do the same to each of the series of filters;
instead of using a series of filters I may in this case use only one filter.
In order to keep the passage of the sewage as even as possible through the bed
I may provide perforated divisions across the filter or may use finer material for
the bottom of the layer of material than for the top thereof, these arrangements
will however vary according to the fall given to the floor of the filter.
Another part of this head of my invention consists of an apparatus for automati-
cally letting sewage on to or out from filters, the apparatus consists of a vessel
having in the bottom thereof apertures or ports each one communicating with a
separate filter either as an inlet thereto or outlet therefrom, a disc or discs with
one or more apertures or ports therein or an arm or arms is provided which fit
or fits over the said bottom of the vessel so that when the said disc or discs or arm
or arms is or are revolved the sewage is allowed to flow in or flow out and is then
cut off from the filters in rotation.
I provide one said vessel as described each for the inlet to and outlet from the
filters, they may be one below the other and worked by the same shaft; the power
to work the shaft I preferably obtain from the sewage itself.
Dated this Wiftarnth dose of Wal
1007
Improvements in the Purification of Sewage and Polluted Water, and
in Apparatus therefor.
I, FRANK PULLEN CANDY, of Ivy Bank, Ashley Road, Bowdon, in the County 4
of Cheshire, Sanitary Engineer, 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:-
The first head of my invention relates to improvements in precipitation tanks

page_text: and the second part of my invention relates to improvements in filters; and in
apparatus therefor.
The sewage or polluted water I will hereafter speak of as sewage.
Referring to the first head of my invention, which specially deals with upward
flow precipitation tanks, I divide the said tank vertically or thereabouts into two
or more chambers or compartments, preferably more than two, by means of
divisions or walls which do not extend down to the bottom of the tank and pre-
ferably extend above the water level of the tank, each said division (unless used
for inlet of the sewage) being provided with one or more effluent take off troughs
or conduits to convey away the treated sewage, so that by means of this said con-
struction a more even flow of sewage upwards through the tank is obtained; the
tendency of the sewage in the ordinary upward flow tank being to flow more or
less in lines and not to have an uniform bodily rise, which said tendency militates
against the best results being obtained: the space between the bottom of the said
divisions or walls and the floor of the tank may
as a common
serve as a
common
sludge. For
sewage feed and
place of deposit for the
example and referring to Figs. 1 and 2 of the drawings which illustrate
plan & section of tank I may divide the tank by four vertical cross walls a, b, c, d,
which I preferably carry about six inches above the water level k of the tank.
into nine compartments, a central one and eight outside ones; the said walls are
in pairs, with about equal distances between each other and from each to the sides
of the tank, each wall of the pairs are about parallel with each other but one pair
runs at right angles to the other pair so that the pairs cross; the bottom of the
walls I carry to within two or three feet of the floor of the tank and support them
upon girders e or in other convenient manner. I provide a pipe f to carry the
sewage into the central compartment and furnish each of the other compartments,
at the top, with one or more overflow exit carriers 9 which discharge the settled
sewage from the tank into a carrier running around the tank. In working,
the sewage enters the central compartment at the top, flows down the same and
discharges into the space underneath the divisional walls from which it has to
rise up through each compartment in order to get out of the tank; and by setting
the overflow exit carriers to discharge at their proper proportional speed an uniform
is pre-
rate of flow and working is maintained throughout the tank and the sewage
vented from flowing in lines and thereby rising to the top of the tank before it has
had time for proper settlement, the sludge deposited on the floor of the tank may
be withdrawn by any convenient means; or instead of dividing the tank as
described I may divide it by walls all of which run parallel or thereabouts to each
other, and may not then use one of the compartments to convey the sewage to
the bottom of the tank but may provide a special pipe for the purpose.
As a modification of this construction I may form each said chamber or compart-
ment practically as a separate tank provided with its own sewage inlet and effluent
take off conduit or conduits and sludge removal arrangement, the whole being
within one tank arrangements being provided by means of valves so that each said
chamber or compartment (when they are being filled) may fill evenly or practi-
cally so, whereby the aforesaid divisions or walls having to bear no or little strain
may be constructed very cheaply.
A further modification consists in constructing within the tank and parallel
or thereabouts with the sides of the tank a wall or walls as a, b, c, d, Figs. 3 and 4
which illustrate plan and section of a tank forming an inner tank, m Figs. 3 and 4
the said wall or walls do not extend down to the bottom of the tank, so that the
sewage entering between these two walls or sets of walls shall flow down towards
the bottom of the tank and then have to rise up within the said inner tank before
it can escape by means of the effluent take off conduits n Figs. 3 and 4 which are
situated within the said inner tank p Figs. 3 and 4 is the sewage delivery channel.
Referring to the second head of my invention I provide two or more filters
situated each at different levels, and arranged so that the sewage is first let into
the highest filter, and, after the same is full, the inlet of sewage is turned off

page_text: therefrom, the sewage in the highest filter is then (or after a period
of rest) allowed to run into the next highest filter and so on for each filter,
meanwhile as soon as the highest filter is empty (or after a period of rest)
it is again filled with sewage which passes in a similar manner down through the
other filter or filters, so that the filters successively undergo a series of charges 5
of sewage and rest or aerations. I prefer the flow of sewage through these filters
to be horizontal or lateral and not vertical; mechanical arrangements are provided
whereby the flow of sewage is caused to open and close the necessary valves or
ports so that the cycles of work and rest as before described shall be automatically
controlled and worked.
1
It will be evident that when the sewage is automatically turned off from the
top filter it must be either stored or turned automatically into another set of similar
filters and be then turned automatically again in due course into the first highest
filter, and so on; I therefore provide a receptacle to store the sewage until
the filter is ready to receive it again, or else I provide a duplicate series of filters into 1
which the sewage shall be intermittently turned.
For example see Figs. 5 and 6 which illustrate plan and section of the filters
I may construct three filters 1, 2, 3 at different levels and holding the same quan-
tity of sewage the top of the middle level filter 2 being a few inches below the
bottom of the highest filter 1 and the top of the lowest filter 3 being a few inches 2
below the bottom of the middle level filter 2, the lowest filter having a free discharge
from the bottom; I also construct receiving tank 4, to discharge sewage by means
of a syphon 5 or its equivalent on to the highest filter 1, and at the outlet end of
each of the filters I also provide syphons 6, 7 and 8 or their equivalent which in
the lower filter discharges its filtrate into the outlet conduit 9 and in the others 2
discharge their filtrates into the filter below. 10 and 11 are the spreading and collecting
conduits of the filters. The inflow of sewage into the receiving tank and the
syphons discharges being so regulated that the alternate working resting (if any)
and aerating of the filters is automatically carried out as desired; instead of a receiv-
ing tank and syphon discharge I may work the filters in duplicate sets; I would 3
then divide each filter as before described, longitudinally into halves, furnishing
each half with syphon outlets and provide the highest pair of tanks with automatic
changer whereby the sewage shall be alternately delivered into and shut off from
each, so that each of the duplicate sets goes through its complete cycle of work
and rest it is evident that the aeration is in its frequency proportional to the 3
number of different level filters.
Another part of this head of my invention consists of an apparatus for automati-
cally letting sewage on to or out from a filter; the apparatus consists see
Figs. 7 and 8 which illustrate plan and section of a vessel 12 having in the bottom
thereof apertures 13, 14, 15 and 16 each one communicating by means of a con- 4
duit 17, 18, 19, 20, with a separate filter, either as an inlet thereto or outlet there-
from, the said vessel having also, preferably in its side, an opening 21 through
which sewage is conveyed to or from the vessel as may be necessary; a disc 22
or discs or its equivalent with one 23 or more orifices therein is provided, which
discs or disc fit or fits over the said apertures in the vessel so that when the said 4
disc or discs or its equivalent is or are revolved or moved the sewage is allowed
to flow into or flow out from each said aperture in its turn, each aperture being then
closed; by this means I am enabled to conveniently regulate the cycle of working
resting (if any) and aerating to a series of filters; the precise arrangement of the
said apertures and of the said disc or discs and the orifice or orifices therein, will 5
depend upon the exact cycle of operations it is desired to give the filters; it will be
evident that by this said apparatus there is a very considerable latitude of arrange-
ment obtained.
I provide one said vessel as described each for the inlet to and outlet from the
filters, they may be one below the other and worked by the same shaft; the power 5
to work the disc or discs I preferably obtain from the sewage itself.

page_text: It will be evident that I may place the aforesaid apertures in the side of the
vessel instead of in the bottom.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. A precipitation tank divided into a number of compartments up which the
liquid shall flow and escape from the top, liquid being supplied to the lower parts
of the said compartments, substantially as and for the purposes described.
2. A precipitation tank divided into a number of compartments by means of
divisions extending above the water level of the + ✓ ut not reaching down to
the floor of the tank a common supply for lithe said divisions, and one or
more outlets for the escape of the liquid om each said compartment being
provided.
3. A precipitation tank divided in cwo parts by means of a wall or walls ex-
tending above the water level one tank but not reaching down to the floor of
the tank so that liquid let into the outer part shall flow down therethrough and
rise up in the other part of the tank and escape from the top thereof substantially
as described.
4. The combination and method of working filters arranged at different levels,
so that liquid sent intermittently into the first filter shall fill up the same and then
be discharged into the next lower bed which after filling shall discharge into the
next lower bed to it (if any) and so on for each successive bed, whereby alternate
working and resting or aerating is provided, substantially as described.
5. For regulating the delivery of liquid to or from filters, apparatus consisting
of a vessel having a number of apertures communicating with the filters, a moving
disc with one or more orifices therein passing over the mouths of the said apertures
thereby opening and closing them, substantially as described.
Dated this Thirteenth day of November 1897.