Apparatus and method for treating water in containers for cultivating marine organisms

Abstract

An apparatus and method for treating water in a marine organism cultivation container are disclosed. The apparatus comprises a container (12) and at least two separate chambers (14) located inside and outside the container. A pipe (16) is arranged to conduct water from the container (12) sequentially through the first and second chambers (14), where it is simultaneously treated and then returned to the container (12). The water in the pipe is brought to a negative pressure by a suitable device for transferring water between the container (12) and the chambers (14). Gas is applied to the pipe (16).

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for treating a liquid in a tank. [Background technology]

[0002] A rapidly growing world population requires increased production of marine proteins. The environmental challenges associated with today's open-ocean aquaculture of marine organisms increasingly necessitate production in closed tanks or tanks both on land and offshore. Currently, there is competition for space available for aquaculture both on land and offshore. There is also a significant challenge in reducing the energy demand for aquaculture in closed facilities. Summary of the Invention [Problem to be solved by the invention]

[0003] The problem of the present invention is to find a solution for effective water treatment in a tank or vessel.

[0004] The object of the present invention is therefore to provide a solution for the treatment of water in tanks, whether they are tanks for the cultivation of marine species or tanks for wastewater to be treated.

[0005] By closed tank is meant here a container or tank that is closed to the surroundings at the bottom and on the edges, in contrast to conventional fish cages that have a mesh structure that is open to the surroundings, such as the sea.

[0006] Furthermore, it is an object of the present invention to provide a solution for water treatment in a tank that does not have a central column.

[0007] Yet another object of the present invention is to easily increase the purity of water in existing tanks with low water purification capacity by taking water through an opening in the tank wall, treating it, and returning it through an opening in another location in the tank wall.

[0008] Discussion of the Prior Art The solution according to the invention is well suited for use in tubular water treatment devices such as those described in PCT / NO2020 / 50108, which are units that transport water from one location to another under negative pressure. In this case, the water is gassed and exchanged, and particles are also removed during this transport. The solution therefore represents a new way to integrate tubular water treatment devices such as those described in PCT / NO2020 / 50108 into a tank.

[0009] To achieve the most energy-efficient water purification, it is important to avoid moving water from a tank for treatment and then pumping it back into the tank. This water movement requires a lot of energy. Many tanks in use today are polygonal tanks with straight sidewalls because they are inexpensive and can be constructed from concrete and steel. They are spatially efficient because they can be placed side by side, making better use of available space than circular tanks. Therefore, octagonal tanks are widely used because they are spatially efficient while providing a good flow pattern for circulating water within the tank. Rectangular tanks have poor flow patterns because stagnant water with particle accumulation occurs in the corners. Circular tanks provide the best flow pattern but are spatially inefficient. [Means for solving the problem]

[0010] Thus, in a first aspect, the present invention relates to an apparatus for treating water in a tank, characterized in that the tank comprises a main chamber for cultivating marine organisms and additionally two or more separate chambers arranged for treating the water in the tank, with a pipeline arranged between the two separate chambers. The water in the tank is led to the first chamber and then further led through the pipeline to the second chamber. The water is then returned to the tank. The pipeline is used to treat the water. Pressure reduction means are used to establish a negative pressure in the pipeline. Gas or air is added to the pipeline.

[0011] In one embodiment, water is transferred under negative pressure in a pipeline from a chamber at the edge of the tank to another chamber at the edge of the tank. The water intake leads to the external chamber through a fitting or directly from the external tank wall. The outlet back into the tank is from an external tank volume with an opening into the tank or directly from the external tank wall. Gas is added to the pipe. A vacuum pump sucks out the added gas to maintain the negative pressure in the pipe.

[0012] In one embodiment, the separate chamber is located inward relative to the tank wall of the main chamber.

[0013] In one embodiment, the separate chamber is positioned externally relative to the tank wall of the main chamber.

[0014] In one embodiment, one or more chambers are located on the inside and one or more chambers are located on the outside relative to the tank wall of the main chamber.

[0015] In one embodiment, the water in the pipeline is circulated by a pumping system or gas lift.

[0016] In one embodiment, the pumping device is located in the tank wall where the water returns to the tank.

[0017] In one embodiment, air is added at the bottom along the length of the pipe and is sucked out through one or more suction ports along the top of the pipeline.

[0018] In one embodiment, the air is added in the form of bubbles, the bubble size being selected based on the type of particles and gases to be removed from the water.

[0019] In one embodiment, the tank is a polygonal tank.

[0020] In one embodiment, the tank is an octagonal tank.

[0021] In one embodiment, the tank is circular.

[0022] In one embodiment, the pipeline is a closed channel.

[0023] In one embodiment, the pipeline is an integral structural part of the tank rim.

[0024] In one embodiment, the pipe system travels from one external volume to another external volume within the tank, with water being directed in and out of the tank wall through openings.

[0025] In one embodiment, a pipeline goes from one tank to another, with a corresponding pipe returning the same amount of water to the original tank.

[0026] In one embodiment, oxygen is added to the water volume before the water enters the tank.

[0027] In one embodiment, the cyclone separates the liquid and gas within the pipeline, with the gas being pumped out through a vacuum pump while the liquid is drained.

[0028] In one embodiment, the external volume / chamber is divided into two portions, each with an inlet and an outlet.

[0029] In a second aspect, the present invention relates to a method for treating water in a tank, in which water is transported in a pipeline under negative pressure from one location on the edge of the tank to another location on the edge of the tank, characterized in that: a water intake leads to the external tank volume through a fitting or directly from the external tank wall; an outlet is from the external tank volume with an opening into the tank; gas is added to the pipeline; and a vacuum pump sucks out the added gas to maintain the negative pressure in the pipe.

[0030] In one embodiment, the water is returned to the tank by a circulation pump through an opening in the tank wall.

[0031] In one embodiment, oxygen is added to the water volume before it enters the tank. [Brief explanation of the drawings]

[0032] [Figure 1] This is a schematic diagram of an octagonal tank with four separate exterior volumes at each of its four corners. These separate chambers communicate with the octagonal tank itself for water intake and discharge to and from tubular water treatment devices (two tubular water treatment devices are shown). The intakes to the exterior separate chambers may be open fields with gratings to prevent fish from swimming in, or they may be smaller, point-like intakes. Similarly, the water return to the tank may be an opening designed to achieve a desired flow pattern. [Figure 2] 1 is a schematic diagram of an octagonal tank with four tubular water treatment units with water intakes and outlets in corner volumes, each separated by a divider from the main chamber where marine species are cultivated. [Figure 3] This is a schematic diagram of the direction of water flow through the tubular water treatment device. The water intake is indicated by the red arrow. The pumping device, used to return the water to the tank, is indicated by the blue arrow. [Figure 4]1 is a schematic diagram of an octagonal tank with an external volume for water intake and discharge to and from a tubular water treatment device, the chambers being shown as cylindrical tanks. [Figure 5] 1 is a schematic diagram of a circular tank with a tubular water treatment device having intake and discharge volumes along the edge and located on the outside of the tank wall. DETAILED DESCRIPTION OF THE INVENTION

[0033] The described solution is particularly suited to octagonal tanks 12, but can be used for tanks with three or more sides 12a. In a preferred embodiment, the tank is octagonal. The external space formed at the corners 12b is utilized by extending the side edges, making the octagonal tank square (see FIG. 1). This creates four external, separate corner volumes 14, which serve as inlets 14b and outlets 14c for the tubular water treatment devices 16. Two tubular water treatment devices 16 are then present within the octagonal tank 12. By dividing the corner volumes 14 into two sections with walls, the octagonal tank 12 can accommodate four tubular water treatment devices 16 along the edges 12a or as an integral part of the edges 12a, as shown in FIGS. 2 and 4. In this way, an energy-efficient and area-efficient solution can be achieved.

[0034] When water is transported under reduced pressure (vacuum) through the tubular water treatment device 16 and gas is added to replace gases dissolved in the liquid, the water in the corner volumes 14 where the outlets 14c are located will have a gas saturation of <100%, e.g., typically 90%. Therefore, the solution according to the invention can be effectively used, for example, to add oxygen to these outlet volumes. After a period of marine life cultivation, the water becomes undersaturated with gas (oxygen), and then oxygenation of the water occurs rapidly, resulting in water that again has 100% gas saturation but >100%, e.g., 130% oxygen saturation.

[0035] The transfer of water into and out of the corner volume / chamber 14 can be through openings in the chamber wall 14a, such as holes 14b, 14c covered with a perforated grid to prevent fish from swimming in. There can be one or more holes 14b, 14c, or the partition 14a can be a larger perforated section. The outlet 14c returning to the tank 12 can be a pipe (part of 16) angled to contribute to good water circulation within the tank 12. A pumping device 18 can also be placed in this pipe. This pumping device 18 ensures the necessary water flow through the tubular water treatment device 16.

[0036] As a result of the test, a tubular water treatment device with a diameter of 1.2 m and a length of 11 m was able to discharge 20 m of water per minute. 3 It has been shown that the energy consumption for transporting 11.5 kWh of water is 1.5 kWh for the circulation pump and 10 kWh for the water degassing process. This results in a 50% reduction in CO2 in the water, resulting in a TGP of 91% at the outlet 14c. By adding O2 to the outlet volume, an oxygen saturation of 130% is typically achieved at a TGP of 100%.

[0037] The present invention provides a method for integrating a tubular water treatment device 16 into a tank 12. This method has proven to be an area-efficient and energy-efficient solution, and is particularly suitable for use with polygonal tanks.

[0038] The solution can also be used with circular tanks. However, in that case the corner volumes must be designed as semicircles on the outside of the tank or as freestanding tanks. This is not only area-efficient but also at least equally energy-efficient. The tubular water treatment device can be an integrated part of the upper edge of the tank, or it can be placed on or along the tank edge or as a secant above the tank.

[0039] It should also be emphasized that the present invention is very well suited to tanks that do not have a central column, and this solution can function as an add-on device in existing tanks.

Claims

1. 1. An apparatus for the treatment of water in a tank (12), said tank (12) comprising a main chamber (12) for cultivating marine organisms and additionally two or more separate chambers (14) arranged for treating the water in said tank (12), characterized in that a pipeline (16) is arranged between two of said separate chambers (14), the water in said tank (12) is led to the first chamber (14) and then further led through said pipeline (16) to the second chamber (14) and then the water is returned to said tank (12), said pipeline (16) is used to treat the water, pressure reduction means are used to establish a vacuum in said pipeline (16), and gas or air is added to said pipeline (16).

2. 2. The device according to claim 1, wherein water is transported under vacuum in a pipeline from one chamber (14) on the tank rim (12a) to another chamber (14) on the tank rim (12a), the water intake is to an external chamber (14b) through an opening or directly from the external tank wall, the outlet (14c) back into the tank (12) is from an external tank volume (14) with an opening into the tank (12) or directly from the external tank wall, gas is added to the pipe (16), and a vacuum pump sucks out the added gas to maintain the vacuum in the pipe (16).

3. 2. The device according to claim 1, characterized in that the separate chamber (14) is arranged internally with respect to the tank wall (12a) of the main chamber (12).

4. 2. The device according to claim 1, characterized in that the separate chamber (14) is arranged externally with respect to the tank wall (12a) of the main chamber (12).

5. 5. The device according to claim 3 or 4, characterized in that one or more chambers (14) are arranged inside and one or more chambers (14) are arranged outside with respect to the tank wall (12) of the main chamber (12).

6. 2. The device according to claim 1, characterized in that water is circulated in the pipeline (16) by means of a pumping device (18) or a gas lift.

7. 7. The device according to claim 6, characterized in that the pump device (16) is arranged in the tank wall (12a) through which water returns to the tank (12).

8. 10. The apparatus of claim 1, wherein air is added to the bottom along the length of the pipe (16) and is sucked out through one or more suction ports along the top of the pipeline (16).

9. 10. The apparatus of claim 1, wherein the air is added in the form of bubbles, the bubble size being selected based on the type of particles and gases to be removed from the water.

10. 2. The device according to claim 1, characterized in that the tank (12) is a polygonal tank.

11. 11. The device according to claim 10, characterized in that the tank (12) is an octagonal tank.

12. 2. The device according to claim 1, characterized in that the tank (12) is circular.

13. 2. The device according to claim 1, characterized in that the pipeline (16) is a closed channel.

14. 10. The device according to claim 1 or 9, characterized in that the pipeline (16) is an integral structural part of the tank rim (12a).

15. 9. The device according to claim 1, 7 or 8, characterized in that the pipe system (16) passes from one external volume to another external volume in the tank (12), and water is led in and out of the tank wall (12a) through openings (14b, 14c).

16. 2. The device according to claim 1, characterized in that the pipeline (16) goes from one tank (12) to another tank (12) and the corresponding pipe (16) returns the same amount of water to the original tank (12).

17. 12. Device according to claims 1 and 11, characterized in that oxygen is added to the water volume before it enters the tank (12).

18. 2. The device according to claim 1, characterized in that a cyclone separates liquid and gas in the pipeline (16), the gas being discharged through a vacuum pump while the liquid is drained.

19. 16. The apparatus of claims 1 and 15, wherein the external volume is divided into two portions, said portions having an inlet and an outlet.

20. 1. A method for treating water in a tank (12), characterized in that water is transported under vacuum in a pipeline (16) from one location on the tank edge (12a) to another location on said tank edge (12a), the water intake is through an opening or directly from the external tank wall (12a) to an external tank volume (14), the outlet (14c) is from the external tank volume (14) having an opening into said tank (12), gas is added to said pipeline (16), and a vacuum pump sucks out the added gas to maintain the vacuum in said pipe (16).

21. 21. A method according to claim 20, characterized in that the water is returned to the tank (12) by means of a circulation pump through an opening (14c) in the tank wall (14a).

22. 21. A method according to claim 20, characterized in that oxygen is added to the water volume before it enters the tank (12).

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