AU2017100597A4 - Aquaculture faeces collector apparatus - Google Patents

Abstract

An aquaculture faeces collector is provided. The aquaculture faeces collector comprises one or more hollow cones, each cone having a first open end and a second end; and one or more receptacles, each receptacle attachable to a second end of a distinct cone and configured to collect aquaculture faeces. The one or more hollow cones are arranged to form a unitary structure which is configurable to be suspended from a frame of a fish farming system. A - 26 -- A

Description

1 2017100597 23 May 2017 "Aquaculture faeces collector apparatus"

Technical Field [0001] This invention relates to an aquaculture faeces collector apparatus for use in fish farming pens, for instance open net-cage farming or closed aquaculture systems.

Background [0002] Intensive fish farming in floating pens causes faeces pollution of about 1.5 times the mass of fish produced. If the currents are weak or the depth of water too shallow, then there is a build-up of rotting matter, with a significant biological oxygen demand. Under some conditions the rotting matter is removed by benthic organisms, otherwise bacteria digest the matter using oxygen. Eventually the water becomes anoxic and the fish are killed. Attempts have been made to retain the faecal matter on flat bottomed pens but the recovery of the faecal matter is labour intensive and inefficient.

[0003] It is desired to address or ameliorate one or more shortcomings or disadvantages associated with prior devices and means to remove faecal matter, or to at least provide a useful alternative thereto.

[0004] Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application.

[0005] Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Summary [0006] According to the present invention there is provided an aquaculture faeces collector comprising: one or more hollow cones, each cone having a first open end and a second end; 2 2017100597 23 May 2017 one or more receptacles, each receptacle attachable to a second end of a distinct cone and configured to collect aquaculture faeces; wherein the one or more hollow cones are arranged to form a unitary structure which is configurable to be suspended from a frame of a fish farming system.

[0007] In one embodiment, the, or each, hollow cone may be a frustum of a cone which comprises six sides tapering from the first end to the second end, otherwise referred to as a right-hexagonal pyramid. Preferably the six tapering sides are substantially identical in shape. Alternatively, the, or each, a right-hexagonal pyramid may be truncated.

[0008] In another embodiment, the, or each, hollow cone may be a regular pyramid which comprises four sides tapering from the first end to the second end. Preferably the four tapering sides are substantially identical in shape. The, or each, hollow cone may have the configuration of a truncated regular pyramid. The regular pyramid may be a square pyramid or a rectangular pyramid.

[0009] In any of the above embodiments, and with respect to the or each cone, the tapering side walls are angled to at least 60 degrees with respect to a central axis.

[0010] In any of the described embodiments, the aquaculture faeces collector further comprises a cleaning device adapted to remove faeces from the receptacle of said one or more cones, wherein the cleaning device includes a suction mechanism.

[0011] In use, the aquaculture faeces collector may further comprise a plurality of buoyancy members adapted to suspend the aquaculture faeces collector from a frame of a fish farm within a body of water.

[0012] The sides of each of the cones may be formed from solid, liquid-impervious sheets. Preferably the sides of each of the cones are formed from a plastic woven mesh. The advantage of utilising a plastic mesh type material is that when the aquaculture faeces collector is used in an environment that is subjected to tides, the tidal action has the effect of resuspending particles on the mesh on the upstream side of the cone. An example of a plastic woven mesh material is Vistaweave™. Alternatively the sides of each of the cones may be formed from a reinforced plastic material, for instance a glass reinforced plastic material. 2017100597 23 May 2017 3

Brief Description of Drawings [0013] A specific embodiment of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which:- [0014] Figure 1 shows a diagrammatic top view of an aquaculture faeces collector; [0015] Figure 2 shows a cross section of the aquaculture faeces collector shown in Figure 1 through line A-A; and [0016] Figure 3 shows a section of one panel of a cone of the aquaculture faeces collector shown in Figure 2.

Description of Embodiments [0017] Referring to the drawings, Figures 1 to 3 show an aquaculture faeces collector 10 which is designed to be used with a fish farming system. It should be appreciated that the invention can be utilised with a variety of fish farming systems and therefore should not be limited to use with the particular example described henceforth. By way of example, a fish farming system includes a stock containment net 12 which is suspended from an upper frame 14 configured to float on the surface of the water. The frame 14 is typically comprised of plastic pipe sections which provide the necessary buoyancy by way of the pipe’s diameter (or alternatively by having several concentric rings of pipe). The fish farming system typically also includes a bird net assembly positioned above the fish stock containment net 12. The provision of a bird net assembly is desirable as it assists in preventing the loss of stock from the net which may be otherwise consumed by birdlife. The bird net assembly may include a plurality of upwardly extending connectors 16 which are mounted to the frame 14. A bird net (not shown) substantially covers the opening of the fish stock containment net 12.

[0018] The aquaculture faeces collector 10 is configured to be positioned within the fish stock containment net 12 and is comprised of an array of substantially identically shaped hollow cones 18, each in the form of a truncated right hexagonal pyramid. Each cone comprises six identically shaped side/face panels 20 which form a hexagon in cross-section. All of the cones are attached to one another to form a unitary structure. 4 2017100597 23 May 2017 [0019] The base of each cone 18 (in proximity to the upper frame of the fish farming system) is hexagonal shaped and each of the cone’s side panels 20 taper downward from the hexagonal shaped base to the respective cone’s apex 22. The side panels 20 of each of the cones 18 are formed from a plastic woven mesh material.

[0020] In this embodiment, the circular fish stock containment pen 12 has a diameter of 38.2m. Accordingly the area within the frame 14 is 1146m2. Configuring the aquaculture faeces collector 10 with seven cones 18, the length of each of the side walls at the base is 7.2m. It is desirable that the extent of taper of the side walls 20 from the base to the apex 22 is more than 60 degrees. In this example, if the taper is 65 degrees then the depth of each of the cones is approximately 15m.

[0021] To form the unitary structure, at all locations where neighbouring cones meet 24, the respective edges are first sewn together to give the required shape. The flap formed from the respective and adjacent cone pairs is folded over an approximately 10mm nylon rope, such as that used for large fishing nets, and double sewn. The rope extends beyond the edges of the respective flaps. At the point where three neighbouring cones abut one another 26 at ~120 degrees, the respective ropes are threaded through an eye 28 in a vertical hanging cable 30, tied to one another and weighted with a weight 28a. The sets of rope in turn attach to catenary cables 32 which are strung across the opening of the fish stock containment pen. In instances where the fish farming system includes a bird net assembly, the catenary cables are attached to the upwardly extending connectors 16. In instances where the fish farming system doesn’t includes a bird net assembly, connectors comparable to upwardly extending connectors 16 will be provided and mounted to the frame 14. Such connectors may be manufactured from HDPE and may be mounted vertically with respect to the frame 14, or may be mounted at a non-vertical angle. Still further, the longitudinal edges of each cone also have rope sewn into the combined material formed from the portion of the face along the edge. Sail making fabrication techniques for incorporating the rope into the cones may be utilised. Thereafter, the aquaculture faeces collector 10 is tethered to the upper frame 14 of the fish stock containment system and is configured in use to be suspended beneath the surface of the water and underneath the working volume of the fish fanning system.

[0022] The aquaculture faeces collector 10 further comprises a plurality of weighted receptacles, each in the form of a vessel 34, with each vessel attached at an apex 22 of a 5 2017100597 23 May 2017 distinct cone 18 and configured to resist tidal displacement of the cone. By way of an example only, each vessel 34 may be in the form of an ~40kg glazed terracotta vessel. In use, each vessel will collect fish excrement and further will fill with water which will act to further prevent movement of the cone to which it is attached. Each vessel 34 has six apertures. The ends of the longitudinal ropes will each be threaded through a respective aperture to secure the vessel to its respective cone 18. It should be appreciated that the cones as shown having the configuration of a truncated right hexgonal pyramid may not be truncated and the vessel may sit in the tip of the cone.

[0023] The cleaning device is preferably a suction means adapted to draw faeces and contaminants from the vessel attached at the apex of each of the cones. The cleaning device is preferably controlled remotely from a surface craft whereby a first end of a suction hose 36 is positioned to extend into the vessel and terminate at about 15 to 33 mm above the base of the vessel. The second end of the suction hose is secured to a pump (not shown) to draw out the accumulated faeces and contaminants. Preferably a progressing cavity pump also referred to as mono pump is used to remove the faeces from the 10 due to their priming characteristics and the fact that they can be reversed to pump blockages out of the suction tube. A progressing cavity pump is a type of rotary positive displacement pump that uses a helical shaped rotor turning inside of a double-threaded helical shaped rubber stator. This produces a progressing cavity that moves the liquid through the pump and creates the pumping action. The progressing cavity pump principle is ideal for handling sewerage. The pump design is ideally suited for both low to high flow applications and also allows for the development of multi-stage pumps that increase the pressure handling capabilities. Rather than one pump per cone it is desirable to have a programed rotating valve with the number of inlets corresponding to the number of cones.

[0024] The illustrated embodiment of the aquaculture faeces collector so far described has been described for use in a circular fish farming pen. Indeed for circular fish farming pens it is desirable that, with respect to the aquaculture faeces collector, the base and top of each cone is hexagonal shaped. The number of hexagonal shaped cones may be 3n2-3n+l for n=l:x, where in practice x<5. However, it should be appreciated that the fish farming pens may also be square or rectangular in shape and in such instances, it is desirable that the base and top of each of the cones of the aquaculture faeces collector are respectively square or rectangular in shape, with the number of square or rectangular shaped cones being n2 where 2017100597 23 May 2017 6 n=l:x, where in practice x<10. For very large pens, typically having a diameter exceeding 100m it may be desirable that the depth of the cones is such that each side wall is in the form of an equilateral or substantially equilateral triangle.

[0025] It should also be appreciated that the depth of the cones, whilst partially dependent on the taper of the cone’s side walls, will also depend on the specific application of the aquaculture faeces collector, notably in terms of the specifics of the fish farming since the properties of faecal matter vary with the composition of the fish food. Faecal matter is aggregated with a mucus film which assists the faecal matter to remain essentially intact for a few minutes in seawater. Whilst the faecal matter is intact it falls at about 3cms4. When the faecal matter is disaggregated it falls at less than 0.03 cms'1. Accordingly, in extreme cases of fish food composition it may be necessary to increase the number of cones and thus decrease the depth of the cones. It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. For example, whilst the material from which the cones are manufactured has been described as formed from a woven plastic mesh, it should be appreciated that other materials may be used. For instance, the cones may be manufactured from laminated membranes paneling. The seams of the membranes to be joined may rely on thermo-activated adhesives to create a chemical bond, and may additionally rely on stitching as a secondary mechanical bond. It should also be appreciated that the invention can be utilised with a variety of fish farming systems and therefore should not be limited to use with the particular example described above. The fish farming system may utilise for instance a variety of frames, walkways and mooring configurations.

Claims (5)

1. Claims:

   1. An aquaculture faeces collector comprising: one or more hollow cones, each cone having a first open end and a second end; one or more receptacles, each receptacle attachable to a second end of a distinct cone and configured to collect aquaculture faeces; wherein the one or more hollow cones are arranged to form a unitary structure which is configurable to be suspended from a frame of a fish farming system.
2. 2. The aquaculture faeces collector according to claim 1, wherein the, or each, cone is a truncated right hexagonal pyramid which comprises six sides tapering from the first end to the second end.
3. 3. The aquaculture faeces collector according to claim 1, wherein the, or each, cone is a truncated regular pyramid, which comprises four sides tapering from the first end to the second end.
4. 4. The aquaculture faeces collector according to claim 2 or 3, wherein the tapering side walls are angled to at least 60 degrees with respect to a central axis.
5. 5. The aquaculture faeces collector according to any one of the preceding claims, further comprising a cleaning device adapted to remove faeces from the receptacle of said one or more cones, wherein the cleaning device includes a suction mechanism.