A fish farming system

Abstract

A fish farming system including a tank (110) having one or more vertical partitions (120) positionable at a target height within the tank (110), a fish schooling zone being defined within the tank (110) at a location between the base of the one or more partitions (120) and the bottom of the tank (110); and the tank (110) being operatively connectable to a recirculating aquaculture system.

Description

[0001] A FISH FARMING SYSTEM

[0002] The present invention relates to farming and in particular to fish farming.

[0003] The invention has been developed primarily as a system for creating a current of fdtered water in a fish farming tank and will be described herein with reference to this application. However, it will be appreciated that the invention is not limited to this particular field.

[0004] BACKGROUND OF THE INVENTION

[0005] Any discussion of prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the field.

[0006] AN OBJECT OF THE INVENTION

[0007] It is an object of the invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0008] Groupers are a type of high value fish, particularly in Asia and the Middle East. The complex behaviour of grouper, combined with the unique characteristics of their natural environment, provide demanding constraints on the design of suitable fish farms.

[0009] Recirculated Aquaculture Systems (RAS) are a type of fish farming that requires high fish densities to be commercially viable. Compared to alternative production methods, RAS farms have a significantly smaller discharge water volume, typically less than 1%. As a result, it is much less expensive to clean the discharge water from RAS farms than from alternative production systems.

[0010] Known fish farming techniques, such as RAS, are not suitable for farming groupers at high densities. Groupers tend to school closely together in a dense pack within one area of the tank. This causes the flow structure within the tank to flow around the school, resulting in little water exchange within the school. Additionally, grouper fish prefer high water temperatures ranging from 27-30 degrees Celsius, which lowers the oxygen carrying capacity of seawater. Under these conditions Groupers can experience oxygen undersupply under otherwise optimal feeding and growth conditions. Ammonia levels within the school can reach critical levels.

[0011] Strong currents or vortexes within the tank are also detrimental to the well-being of grouper fish.

[0012] Biofilters for RAS in general, besides being expensive, tends to potentially generate anoxic zones, which especially in warm seawater may generate toxic levels of sulphide, which can cause mass mortalities within a fish farm. A new water extraction device has been included in this invention, to be installed within the biofilter, which can reduce the investment on biofilters, and at the same time minimize the risk of sulphide production within the biofilter.

[0013] It is an object of the invention in its preferred form to provide a fish farming system that provides adequate oxygen to the fish and keeps ammonia levels in the tank low by allowing filtered water to exchange within the school of fish while also allowing an increased density of fish being farmed.

[0014] SUMMARY OF THE INVENTION

[0015] According to the invention there is provided a fish farming system including: a tank having one or more vertical partitions positionable at a target height within the tank, a fish schooling zone being defined within the tank at a location between the base of the one or more partitions and the bottom of the tank; and the tank being operatively connectable to a recirculating aquaculture system.

[0016] The one or more vertical partitions preferably extend from one side of the tank to another side.

[0017] There is preferably further included a low-pressure recirculation vessel operatively connectable to a pump adapted to actuate low-pressure flow within the vessel, each end of the vessel being in fluid communication with the tank.

[0018] Preferably, there is further included an air pump operatively connected to the fluid recirculating vessel, the air pump being adapted to inject air into the vessel and actuate low-pressure flow within the vessel. At least one end of the vessel is in fluid communication with a tank wall at a location preferably between 0.4 meters and 2.0 meters below a fluid level within the tank.

[0019] Preferably, there is further included an oxygen injection unit adapted to provide oxygen to the tank.

[0020] There is preferably included one or more chemical dosing pumps adapted to deliver one or more chemicals to the tank(s) according to requirements.

[0021] Preferably, a water mixing device is operatively connected to the tank, the water mixing device being adapted to mix water from two separate sources.

[0022] The recirculating aquaculture system preferably includes a fluidized biofilter.

[0023] The fluidized biofdter preferably includes a mixing chamber and one or more water extraction, devices. The water extraction device (s) having a partition extending in parallel to a chamber wall and from one side of the water extraction device to another, the partition being open at its top and its bottom such that the contents of the mixing chamber can be directed to flow under partition and then to separate into a first and a second stream, the first stream flowing out of the biofdter through a classifying screen, the second stream flowing over the top of the partition and back into the mixing chamber.

[0024] The first and second streams are actuated by preferably an aeration device located adjacent to the top of the water extraction device.

[0025] BRIEF DESCRIPTION OF THE DRAWINGS

[0026] A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0027] Figure 1 is a simplified flow diagram illustrating an embodiment according to the invention. Figure 2 is a side view layout of a water extraction device within a biofdter according to the invention.

[0028] Figure 3 is a side view layout of the water extraction device without the outer wall to underline the placement of the aeration pipe.

[0029] Figure 4 is a side view layout of the water extraction device .

[0030] Figure 5 A is a side view layout of a single water extraction device according to the invention.

[0031] Figure 5B is a double water extraction device according to the invention.

[0032] Figure 6 is a top view layout illustrating an embodiment according to the invention.

[0033] Figure 7 is a side view layout illustrating an embodiment according to the invention.

[0034] PREFERRED EMBODIMENT OF THE INVENTION

[0035] Referring to the drawings, the fish farming system has a tank (110) with vertical partitions (120) positionable at a target height within the tank (110). The vertical partitions (120) extend from one side of the tank (110) to the other side. A fish schooling zone is defined within the tank (110) at a location between the base of the partitions (120) and the bottom of the tank (110). Tank (110) is connected to a recirculating aquaculture system.

[0036] The system has a low-pressure recirculation vessel operatively connected to a pump adapted to actuate low-pressure flow within the vessel by injecting air into the vessel. Each end of the vessel is in fluid communication with the tank (110). One end of the vessel is in fluid communication with a tank (110) wall at a location between 0.4 meters and 2.0 meters below a fluid level within the tank (110).

[0037] The system also has oxygen injection unit adapted to provide oxygen to the tank (110), a chemical dosing pumps adapted to deliver one or more chemicals to the tanks (110) according to requirements, and a water mixing device / zone operatively connected to the tank (110). The water mixing device / zone is adapted to mix water from two separate sources.

[0038] The recirculating aquaculture system further includes a fluidized biofilter (200).

[0039] The fluidized biofilter (200) includes a mixing chamber (210) and one or more water extraction devices (240), the water extraction device(s) (240), having a partition extending in parallel to a chamber wall and from one side of the water extraction device (240) to another, the partition being open at its top and its bottom such that the contents of the mixing chamber (210) can be directed to flow under partition and then to separate into a first and a second stream, the first stream flowing out of the biofilter (200) through a classifying screen (220), the second stream flowing over the top of the partition and back into the mixing chamber (210).

[0040] The first and second streams are actuated by an aeration device (230) located adjacent to the top of mixing chamber (210).

[0041] To farm fish in with the farming system, firstly, the vertical tank positions are positioned at a target height within the tank (110) to define a schooling fish zone between the base of the partitions (120) and the bottom of the tank (110).

[0042] Then pumps within the recirculation system which can be installed somewhere within the flow of the recirculation / water treatment system, as example illustrated after mechanical filters Figure 1., are turned on to drive the flow of water between the fish tanks (110) and the recirculation system - including the biofilter (200).

[0043] Next oxygen injection unit, as well as the pump, thus actuating low-pressure flow with the recirculation vessel by injecting air into the vessel. Within the biofilter (200), the aeration device (230) is also turned onto actuate the flow of the first and second streams, the first stream flowing out of the biofilter (200) through a classifying screen (220) to produce filtered water which is resupplied to the tank (110).

[0044] The fish can now be introduced into the schooling fish zone wherein a flow of water (i.e., current) is created between the base of the partitions (120) and the bottom of the tank (110) by means of the low-pressure flow entering the tank (110) from the recirculation vessel.

[0045] The fish swim against the current, experiencing a gentle flow of filtered water which is more optimal than even a natural environment, allowing a high density of fish to be farmed.

[0046] Figure 1 is a simplified flow diagram illustrating two water treatment technologies employed around the tank (110): the extended flow through a series of water treatment devices and the in -tank water treatment loop. The diagram also highlights the additional oxygen control implemented in the system, as well as the integration of an active CO 2 stripper. This visual representation showcases the comprehensive approach taken to ensure effective water treatment, oxygenation, and CO2 management within the tank (110), contributing to the overall success of the farming process. Figure 2 is a side view layout of a single water extraction device (240) within a biofilter (200).

[0047] Emphasizing the flow within the biofdter (200) and the outlet box.

[0048] Figure 3 is a side view layout of the water extraction device (240) without the outer wall to underline the placement of the aeration pipe.

[0049] Figure 4 is a side view layout of the water extraction device (240).

[0050] Figure 5A is a side view layout of a single water extraction device (240) according to the invention. Figure 5B is a double water extraction device (240) according to the invention. Emphasizing their relative flow design in combination to the placement of the aeration pipe.

[0051] Figure 6 and Figure 7 illustrate possible configurations of how the water extraction devices (240) potentially could be installed within a biofilter (200). The water extraction device (240) is configured to be positioned in the mixing chamber (210) within the biofilter (200) . The water extraction devices (240) can as illustrated be positioned without direct connection to the biofilter tank wall, or alternatively be integrated with the biofilter tank wall.

[0052] It will be appreciated that the illustrated fish farming system provides adequate oxygen to the fish and keeps ammonia levels in the tank (110) low by allowing filtered water to exchange within the school of fish while also allowing an increased density of fish being farmed.

Claims

CLAIMS1. A fish farming system including: a tank (110) having one or more vertical partitions (120) positionable at a target height within the tank (110), a fish schooling zone being defined within the tank (110) at a location between the base of the one or more partitions (120) and the bottom of the tank (110); and the tank (110) being operatively connectable to a recirculating aquaculture system.

2. A fish farming system according to claim 1, wherein the one or more vertical partitions (120) extend from one side of the tank (110) to another side.

3. A fish farming system according to claim 1 or claim 2, further including a low-pressure recirculation vessel operatively connectable to a pump adapted to actuate low-pressure flow within the vessel, each end of the vessel being in fluid communication with the tank (HO).

4. A fish farming system according to claim 3, further including an air pump operatively connected to the fluid recirculating vessel, the air pump being adapted to inject air into the vessel and actuate low-pressure flow within the vessel.

5. A fish farming system according to any one of the preceding claims, wherein at least one end of the vessel is in fluid communication with a tank wall at a location between 0.4 meters and 2.0 meters below a fluid level within the tank (110).

6. A fish farming system according to any one of the preceding claims, further including an oxygen injection unit adapted to provide oxygen to the tank (110).

7. A fish farming system according to any one of the preceding claims, further including one or more chemical dosing pumps adapted to deliver one or more chemicals to the tank (HO).

8. A fish farming system according to any one of the preceding claims, further including a water mixing device operatively connected to the tank (110), the water mixing devicebeing adapted to mix water from two separate sources.

9. A fish farming system according to any one of the preceding claims, wherein the recirculating aquaculture system includes a fluidized biofilter (200).

10. A fish farming system according to claim 9, wherein the fluidized biofilter (200) includes a mixing chamber (210) and one or more water extraction devices (240), the water extraction device(s) (240), having a partition extending in parallel to a chamber wall and from one side of the water extraction device (240) to another, the partition being open at its top and its bottom such that the contents of the mixing chamber (210) can be directed to flow under partition and then to separate into a first and a second stream, the first stream flowing out of the biofilter (200) through a classifying screen (220), the second stream flowing over the top of the partition and back into the mixing chamber (210).

11. A fish farming system according to claim 10, wherein the first and second streams are actuated by an aeration device (230) located adjacent to the top of mixing chamber (210).

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