Note: Descriptions are shown in the official language in which they were submitted.
WASTE REMOVAL APPARATUS
This invention relates to improvea apparatus
for use in removing waste from a fish culture system.
In a system of this type, whether for breeding
or grow out purposes, or both, the water becomes contam-
inated with excrement, excess food and other waste
material. The resulting dissolved organic substances,
such as ammonia, nitrites and nitrates, will, unless
removed, starve the fish of oxygen, causing the fish to
be killed or diseased, and/or starve the water of
oxygen, causing the fish to starve and promoting other--
wise dormant fish diseases.
A large concentration of fish in the system
thus requires that the waste material, and particularly
the dissolved organic substances, be continuously
removed. Conventional systems for removing the material
have not been found adequate for this purpose, particu-
- larly in systems which are indoors and thus where
surface area is at a premium. Accordingly,
this invention seeks to provide such appara-
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- material, and particularly dissolved organic substances,
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but which occupies relatively little ground area, and
which is relatively inexpensive to manufacture and easy
to maintain.
This and other aspects are accomplished, in
accordance with the illustrated embodiments of this
invention, by apparatus which includes a tank through
which water from the fish culture system may be cir-
culated, and a plurality of filters mounted in upright
and spaced apart positions across the tank so that the
water circulates successively through them. ~ach such
filter includes a relatively thin layer of porous
filtering media having a large surface area on which
bacteria from the dissolved organic substances in the
water will grow, and a means is provided for injecting
lS air into the water on the upstream side of each filter
so as to agitate the water and add oxygen thereto for
promoting the bacterial growth on the filter media.
More particularly, means are provided for maintaining
the water in the tank at substantially the level of the
upper edges of the filter media, and each layer of
filter media is removably mounted in the tank so that it
may be cleaned as it is clogged by the accumulation of
the bacterial growth thereon.
Since the filters are mounted in upright
positions, and relatively close together, they provide
large surface areas on which bacteria may grow with a
minimum ground area requirement. The addition of air to
the water on each upstream side of the filter will
promote maximum bacterial growth on each successive
filter by replenishing the oxygen removed from the water
due to the bacterial growth upon the preceding filter.
The maintenance of the water in the tank at substantial-
ly the level of the upper edges of the filter media
enables optimal use of the surface areas of the filters
and, in the event one filter becomes logged, water is
free to flow over its upper edge so that the process may
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continue both prior to an during its removal for clean-
ing.
In certain embodiments of the invention, the
water level is maintained not only by the levels of the
water inlet and outlet, but also by one or more weirs
which are mounted across and secured to the sides of the
tank to provide support therefore as well as to reduce
the rate of flow of the water through the tank and thus
promote settling of waste. In this same connection,
baffles may also be arranged within the tank upstream of
the filters to further promote the settling of solid
waste particles prior to circulation of the water
through the filters.
The air injecting means includes a series of
tubes each individually mounted on the tank with an
inlet in its lower end near the bottom of the tank, and
an air line extending into the tube for injecting air
into the water near its lower end. Thus, each such tube
may be removed or replaced for repair purposes without
disturbing the filters or the other tubes. Preferably,
the upper, outlet end of each tube opens at generally
the level of the water, which has been found to promote
maximum agitation and oxygenation of the water. In one
embodiment, the inlet to each tube is, like its outlet,
on the upstream side of the filter. In another embodi-
ment, however, the inlet is on the downstream side of
; the filter so that air is injected into water which has
already circulated through the filter.
As illustrated, each filter also includes
screens on opposite sides of the layer of filter media,
and the filter media comprises woven polyester or any
other suitable inexpensive, readily washable material
having a surface area considerably larger than that of
its one side facing the water flow. The screens are of
any suitable non-corrosive material such as plastic
compatible with the water.
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In the drawings, wherein like reference
characters are used throughout to designate like parts:
Fig. 1 is a top plan view of apparatus con-
structed in accordance with the present invention,
including a tank having filters mounted thereacross and
piping for circulating water from a component of the
fish culture system into and through the tank and the
bitters thus for return to the system;
Fig. 2 is a longitudinal, sectional view of
the tank, as seen along broken line 2-2 of Fig. 1, and
showing means constructed in accordance with the first
described embodiment of the invention for injecting air
into the water on the upstream sides of the filters;
Fig. 3 is an elevational view of the outlet
end of the tank, as seen along broken lines 3-3 of Fig.
2;
Fig. 4 is an enlarged cross sectional view of
a portion of the tank illustrating the tube through
which air is injected into the water on the upstream
side of each filter;
Fig. 5 is a cross sectional view of the tank,
as seen along broken lines 5-5 of Fig. 2, and showing in
elevation the back side of a filter;
Fig. 6 is a sectional view of a portion of a
filter showing, on an enlarged scale, the layer of
filter media disclosed between screens on each side; and
Fig. 7 is another cross sectional view of the
tank, as seen along broken lines 7-7 of Fig. 2, and
illustrating the back side of one of the baffles;
Fig. 8 is a longitudinal sectional view,
similar to Fig. 2, of a tank in which air is injected
into the water upstream of each of the filters in tank
by tubes constructed and arranged in accordance with the
second described embodiment of the invention; and
Fig. 9 is a longitudinal section view of the
front end of a tank similar to that shown in Fig. 8, as
well as the rear end of a raceway or breeding tank and a
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pipe extending between the outlet from the raceway to
the inlet to the filter tank.
With reference now the details of the above
described drawings, the tank shown in each of Fig. 1 and
2, and designated in its entirety by reference character
10, is of elongate construction having vertical walls 11
at each end, oppositely facing side walls 12, and a
bottom wall 13 which is curved to cause solid waste
particles to slide downwardly within the tank toward its
lowermost point. Pipes 14 from a raceway or breeding
tank R of the fish culture system extend through the
inlet end wall ll of the tank for introducing water from
the system into the tank near its upper end. Following
circulation through the tank, the water passes through
pipes 15 extending through the outlet end wall of the
tank near its upper end for return to another component
of the fish culture system and ultimately back to the
raceway or breeding tank.
Weirs 16 extend across and are secured to the
2~ sides of the tank intermediate its ends to divide it
into four longitudinally successive compartments A, B, C
and D in which the water in the tank is maintained at
substantially the level of the upper edges of the weirs,
which are in turn at substantially the level of the
inlet and outlet pipes 14 and 15. The water and waste
material in each compartment may be drained therefrom
through a drain pipe 17A, 17B, 17C and 17D in the lower-
most point of each compartment leading to a common drain
line 18. Stand pipes 17AA, 17BB, 17CC and 17DD are
removably disposed in the upper ends of the drain pipes
so as to normally close same.
The compartments A and B are for the purpose
of causing solid waste particles in the water to settle
out onto the bottom of the tank. For this purpose,
baffles 20 are mounted across the tank, with successive
baffles in each compartment being closely spaced apart
~ from one another, and with the side and lower edges of
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the baffles spaced from the side edges and bottom of the
tank so as to promote circulation of water over and
between them as they pass through each of the compart-
ments _ and B. As shown, the leading or upsteam baffle
in each compartment extends above the water level, and
the upper edges of successive baffles are below the
water level.
These baffles may of be any suitable, inexpen-
sive material compatible with the water, such as fiber-
glass reinforced plastic, and are preferably of wavyconfiguration to further promote water circulation.
They are supported in the positions shown by means of
rods 21 extending longitudinally within the compartments
A and B of the tank. Thus, as shown in Fig. 7, holes
are drilled in each baffle to permit it to be moved onto
supported position on the rods.
The compartments C and D, on the other hand,
are for the purpose of removing dissolved organic
substances in the water by bacterial growth. Thus, a
plurality of filters 22 are mounted in upright and
spaced apart positions across the tank within each
compartment so that water passing over the weirs 16, and
through the compartment, will circulate successively
through the filters. That is, as shown in Fig. 5, each
filter has side edges and a bottom edge which conform
closely to the side walls and bottom of the tank.
As previously described, and as shown in Fig.
6, each filter includes a relatively thin layer of
filtering media 23 on which bacteria from the dissolved
organic substances in the water will grow, and screens
24 on opposite sides of the filtering media and secured
thereto by means of a frame 25. As shown in Fig. 5, the
frame has hand holes above the upper edge of the layer
25 to permit the filtering media to be easily removed
from or mounted within the tank. The carrier has
opposite sides which are secured to one another, as well
as the filtering media and screens, so as to hold them
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in place, and has side edges and a bottom edge which are
adapted to fit closely within the side walls and the
bottom of the tank.
As previously described, the layer of filter-
ing media of each filter comprises a material, such as
woven or fiberglass matting, which provides surface
areas many times that of the area on the face of the
layer. Thus, even though the bacteria will not grow on
the layer of filtering media for a depth of more than
one inch or so, the media nevertheless provides surface
areas on which large amounts of the bacteria will grow
before the filter becomes clogged and must be removed
for cleaning and/or replacement.
Furthermore, and as also previously described,
even though the media of one or more filters may clog
up, water is free to flow over the top of the layer, and
thus permit the filtering process to continue. In the
meantime, of course, the clogged filter may be removed
for replacement or repair, also without interrupting the
filtering process through the remainder of the filters.
As also previously described, both the screens and the
carrier may be made of any suitable, light weight
material which is compatible with the water and which is
non-corrosive and otherwise inexpensive.
As best shown in Fig. 4, and as previously
described, the means for injecting air into a column of
water on the upstream side of each filter comprises a
tube 28 mounted on a bracket 29 releasably attachable to
a side 12 of the tank at the upstream side of each
filter, and an air line 30 of plastic of the like which
extends into the tube 28 and which has an airstone 31 on
its lower end adjacent the lower end of the tube, so as
to inject air into the tube for passage upwardly
substantially the entire length of the tube 28 prior to
passing outwardly through the open upward end of the
tube. As shown, the open lower end 32 of the tube is
cut on a bias to provide optimum access of the water to
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the airstone, and the open upper end 33 of the tube
opens to one side thereof. As also previously
described, it is preferred that the tube be so mounted
that the water level in the tank is substantially
intermediate the upper and lower limits of the open
upper end of the tube, and the tube is preferably of
such length that its lower end is near the lower end of
the tank as can be seen from Fig. 2. The bracket has a
series of holes there through, as shown in Fig. 4, to
permit it to be mounted in a plurality of vertical
positions with respect to the tank, and thus with its
upper end at desired elevation with respect to the water
level.
As also shown in the drawings, a similar means
is also provided for injecting air into the upstream end
of each of the compartments _ and B, thereby further
promoting the circulation of water within the compart-
ment. Air is supplied to each air line 30 through a
common air line 34.
Inasmuch as the alternative embodiment of the
tank shown in Fig. 8, and indicated in its entirety by
reference character lOA, is similar in many respects to
the tank 10, many of its corresponding parts are in-
dicated by the same reference character except for the
addition of the suffix "A". Thus, for example, the tank
is shown to be of elongate construction having vertical
walls llA at each end, oppositely facing side walls 12A,
and a bottom wall 13A, which, as in the case of the tank
10, is preferably curved or of U shape to cause solid
waste particles to accumulate at the lowest level
- therein. Also, pipes 14A from a raceway or breeding
tank of the fish culture system extend through the inlet
end wall llA for introducing water from the system into
the tank near its upper end. Still further, the water,
following circulation through the tank, passes out of
the tank through pipes 15A extending through the outlet
end wall of the tank near its upper end for return to
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another component of the fish culture system and
ultimately the raceway.
A weir 16A is mounted across and secured to
the opposite side walls of the tank intermediate its
ends to divide it into longitudinally successive com-
partments CA and DA. The weir has a slot therein whose
lower edge is disposed at substantially the level of the
inlet and outlet 14A and 15A so as to maintain a water
level in the tank as indicated in broken llnes. Water
and waste material may be drained from each compartment
through a drain pipe in the lowermost level of each
compartment leading to a common drail line 18A.
Standpipes 17CCA and 17DDA are removeably disposed in
the upper ends of the drain pipes so as to normally
close them.
If desired, additional compartments containing
baffles may be arranged in a forward extension of the
tank upstream of the compartments CA and DA. As
previously noted in connection with the tank 10, these
baffles may be useful in promoting settlement of waste
material upstream of the compartment CA and DA.
As in the case the compartments C and D of the
tank 10, compartments CA and DA of the tank lOA are for
the purpose of removing dissolved organic substances in
the water by bacterial growth. Thus, as shown, a
plurality of filters 22A are mounted in upright and
spaced apart positions across the tank within each
compartment, with the side and bottom edges of the
filters conforming closely and being secured to the side
walls and bottom of the tank, and with the upper edges
of the filters slightly above the water level, so that
water passing through the tank will circulate
successively through the filters, at least until such
-~ time that the filters are clogged, at which time the
i ' 35 water level will rise sufficiently upstream for that
~l filter to pass over its upper edge.
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As in the case of the filters of the tank 10,
each filter 22A includes a relatively thin layer of
porous filtering material on which bacteria from the
dissolved organic substances in the water will grow.
Although not shown in Fig. 8, the filters 22A also
preferably include screens on opposite sides of the
filtering media and secured thereto by means of a frame,
as shown in Figs. 3, 5, 6 and 7, except that the frames
do not extend upwardly to provide hand holes for
facilitating raising and lowering of the filters.
In still other respects, the filters are
similar to those previously described in that the layer
of filtering material may comprise woven or fiberglass
matting which provides surface areas many times that of
the area on the face of the layer. Also, of course, and
again as previously described, clogged filters may be
removed for replacement or repair, without interrupting
the filtering process through the remainder of the
filters.
The means for injecting air into the water in
the upstream side of each filter is similar to that
described in connection with the tank 10 in that it
comprises a tube 28A releaseably mounted on a side of
the tank and an air line 30A of plastic of the like
which extends into the tube and which has an airstone
31A on its lower end adjacent the lower end of the tube
to inject air into the tube for passage upwardly
substantially the entire length of the tube prior to
passing outwardly through the open upper end of the
tube. Also, and as shown, the open lower end 32A of the
tube 28 is cut on a bias to provide optimum access of
the water to the airstone, and the upper, outlet end 33A
of the tube opens at substantially the water level in
the tank. As shown, and as previously described, the
tube is preferably of such length that its lower end is
near the lower end of the tank.
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The tubes 28A differ from tubes 28, however,
in that their inlet ends are disposed in the downstream
side of each filter so that air lines 30A inject air
into water which has already circulated through that
filter. That is, as shown in Fig. 8, the major portion
of each tube is mounted on the downstream side of the
filter, and has an upper end which extends forwardly
over the upper edge of the filter, and whose open end
faces downwardly at the water level just upstream of the
upper edge of the filter. Thus, this arrangement of the
air injecting tubes enables even greater airation of the
water. Air is supplied to each of the air lines 30A by
means of a common air line 34A leading from a suitable
- source of air.
The embodiment of filter tank lOB shown in
Fig. 9 is similar to the tank lOA of Fig. 8 so many of
its parts are designated by the same reference
characters except for the use of the suffix "B" in place
of "A". Thus, for example, the tank is of elongate
construction and has a front or inlet end wall llB
through which one or more pipes 14B extend from a
breeding tank or raceway RB for introducing water from
the raceway into the tank lOA at its inlet end.
Following circulation through and out of the tank
through outlet pipes, as shown in Fig. 8, the water may
be delivered to another component of this system and
ultimately to the raceway for recirculation through the
tank lOB.
As in the case of tank lOA, a plurality of
filters 22B are mounted in upright and spaced apart
positions across the tank within each compartment
thereof, with the side and bottom edges of the filters
conforming closely to the side walls and bottom of the
tank, and with the upper edges of the filters slightly
above the water level, so that water passing through the
tank will circulate successively through the filters, at
lea~t until such time that the fi1ters are clogged, at
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which time the water level will rise sufficiently
upstream for that filter to pass over its upper edge.
Each of the filters 22B is preferably of the
construction previously described in connection with
Figs. 1 to 8.
Tank lOB is also similar to tank lOA in that
it incudes means for injecting air into the water on the
upstream side of each filter 22B in the form of an air
line 28B releaseably mounted on a side of the tank and a
tube 30B of plastic of the like which extends into the
tube 28B and which has an airstone 31B on its lower end
adjacent the lower end of the tube to inject air into
the tube for passage upwardly substantially the entire
length of the tube 28B prior to passing outwardly
through the open upper end of the tube. As in the case
of the tubes 28A, the tubes 28B have lower inlet ends
32B disposed in the downstream side of each filter and
inlet ends 33B which open on the upstream side of each
filter at the water level in the tank so that they
inject air into water which has already circulated
through that filter. That is, as in the case of Fig. 8,
the major portion of each tube 28BiS mounted on the
downstream side of the filter, and has an upper end
which extends forwardly over the upper edge of the
filter, and whose open end 33B faces downwardly at the
water level just upstream of the upper edge of the
filter. Air is supplied to each of the air lines 30B by
means of a common air line 34B leading from a suitable
source of air.
Each of the inlet pipes 14B to the tank lOB
includes an upright section 40 which extends through a
bottom wall of the raceway RB near the rear end thereof.
More particularly, the upright end 40 of each pipe 14B
is open at its upper end within raceway RB to maintain
the water level therein and is surrounded by an outer
tube 41 which extends above the water level and which
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has a screen 42 at its lower end to prevent fish in the
raceway from passing into the pipe 14B.
Air is injected into the upright section 43 OI
the outlet end of each of the inlet pipes 14s by means
of an air line 44 which may receive air from the common
line 34B. More particularly, air is introduced into the
pipe 14B through a loadstone on the lower end of an air
line located approximately intermediate the upper and
lower ends of the upright section 43. This injection of
air into the inlet pipe thus assists in causing water to
be circulated from the raceway into the filter tank with
substantially no hydraulic loss, and thus maintaining
the water at a level within tank lOB approximately
vertically midway of a horizontal section 45 of the pipe
which extends through wall llB of tank lOB.
From the foregoing it will be seen that this
invention is one well adapted to attain all of the ends
and objects hereinabove set forth, together with other
advantages which are obvious and which are inherent to
the apparatus.
It will be understood that certain features
and subcombinations are of utility and may be employed
without reference to other features and subcombinations.
This is contemplated by and is within the scope of the
claims.
As many possible embodiments may be made of
the invention without departing from the scope thereof,
it is to be understood that all matter herein set forth
or shown in the accompanying drawings is to be inter-
preted as illustrative and not in a limiting sense.
