WO2021262006A1

WO2021262006A1 - Tank for culturing of marine organisms

Info

Publication number: WO2021262006A1
Application number: PCT/NO2021/000002
Authority: WO
Inventors: Morten Aga; Kjell Lorentsen; Arve Storholm; Eldar Lien
Original assignee: Searas As; Gigante Salmon As
Priority date: 2020-06-22
Filing date: 2021-06-21
Publication date: 2021-12-30
Also published as: NO20221140A1; WO2021262006A8

Abstract

Described is a tank system for through flow and recycling solutions for breeding of marine species, which comprises means for sedimentation of particles such as faeces. In principle, the tank system establishes at least two water reservoirs, and the water velocity of flow through the tank is regulated so that the water in one section moves sufficiently slowly and in absence of marine organisms to obtain efficient sedimentation in this water reservoir. Further, fluid is transported between the two water reservoirs with the use of a device which at the same time exchanges gasses in the fluid.

Description

Tank for culturing of marine organisms

WO 2021/262006 PCT/N02021/000002

Field of the Invention

The present invention relates to a tank system for flow through and recycling solutions for breeding of marine organisms. The tank system comprises two water reservoirs, one for breeding of the marine organisms, and one arranged for sedimentation of particles, such as faeces.

Background of the Invention.

Longitudinal flow tank systems and so-called raceways are increasingly used to breed marine species of fish. A longitudinal flow tank may typically be 150 meters long and 15 meters wide. Longitudinal flow tanks are based on water being pumped in at one end and exited in the other, while in raceways, all or parts of the water is led back to the inlet. There may also be 2 tanks placed side by side and where water circulates between the two longitudinal flow tanks. The invention relates to a device by a longitudinal flow raceway where the two tanks are placed side by side or over and under one another, and primarily where there is a single partition wall between the two tanks, where the water flows around in a loop, as on a skating rink, before it is let out from the installation (Fig. 1 ), i.e. two different water reservoirs are established, where one is used to breed marine organisms such as fish, and the other water reservoir is used to circulate all or parts of the water back to the breeding section of the installation.

The challenge of longitudinal flow installations is that to achieve a water flow optimal for the fish when fish stocks are large, enormous amounts of water are required. For example, a salmon of some size will soon require 1 -1 .5 x body length/s. This means that a fish of 50 cm requires 50 cm/s water velocity of flow. In a longitudinal flow installation of 15 width x 5 m water depth and a water velocity of flow of 0.5 m/s, water must be pumped into and out of the installation at a velocity of 37.5 M3 water/sec. In a raceway, this water will be circulated, and energy spent to create current in the water to achieve water velocity of flow. The amount of water that must be changed will be determined by the accumulation of gasses (among others, CO2 and H2S) and particles in the water. When the water is recycled back to the breeding section of the tank, the amount of intake of new (water) may be reduced. In a raceway, the pumping demand for new water into the installation may typically be all the way down to under 10 % of what a through flow installation may require. It will also be possible to have more than two tanks, if practical. For example, one may imagine that several units, as in Fig. 3, float side by side in a large tank system wherein the water volume the unit in Fig. 3 floats, may also be used for water treatment.

Solutions for longitudinal flow tanks and raceways are known, but with the present invention, one of the tanks, or a section of the return tank, form a water reservoir which is optimized for sedimentation of particles, while the other water reservoir or course is optimized for growing of a living marine biomass. Therefore, this invention carries this out in a novel manner by the return course for the longitudinal flow tank being designed for sedimentation of particles, and that the return course or parts/sections of this is without fish. As shown in Fig. 1 , the water flows one way in the tank 12 where the fish is, to then be led to tank 10, using devices 16, and where particles deposit, and the water is lead back to the beginning and into tank 12. To obtain desired velocity of flow for the water, different types of current creating devices (devices 16) may be used together with devices that in addition to establishing flowing also aerates CO2 and oxygenate the water.

One way to construct such a longitudinal flow tank system, is to dig a long pit and mould a first tank. This first tank is filled with water and a further tank, a second tank, is positioned floating in the first tank. The second tank is watertight towards the first tank, with the exception of the end sections which provide communication between the fluid volumes, i.e., fluid flows in one direction in one tank, and at the end section it is lead down into the first tank where the fluid moves in the opposite direction. Pumps are then used to pump the water from the first lower tank to the second tank.

The marine fish species which will be bred, are placed in the second tank 12, and there is a device in the end sections, for example a seine or mesh, which ensures that the fish cannot move from the second tank to the first tank. The challenge of such longitudinal flow tanks is the use of energy to pump the water for circulation through the two tanks, and to maintain appropriate water quality. Oxygen rich and C02 low intake water will have poorer and poorer quality as it flows towards tank 12, and at present there are no good ways to solve this. Especially, it is a considerable problem that the water is polluted with particles, and that large fish need large water velocity of flow, which require large pumps and large through flow. The main principle of such an installation will be to rate tank 1 and 2 in a manner which optimizes the volume where the fish is located in relation to the volume where depositing of particles take place.

In a tank of fish, it is known and observed that the bottom of the tank often is rather clean. This is because the fish create turbulence in the water mass, which lead to the particles not falling towards the bottom and staying at the bottom. Therefore, the central feature of this invention is to have a raceway where one course breed fish, while the second course is constructed for particle deposits. In principle, this may be one tank, but where the tank has two separate sections or courses, where the one section is constructed for breeding of fish and the other section is constructed to allow for sedimentation of particles. Furthermore, it is not a requirement that the tank has a rectangular shape, and it may be oval or circular. For example, the device for sedimentation of particles according to the invention may be used in conventional RAS installations.

When the water reservoir where sedimentation of particles takes place is not the same tank or section of the tank as where the fish is, then the currents in the water are not affected by the fish’s movements. The movements in the water will be much calmer, so that the particles may sink to the bottom of the tank. Different alternative solutions for collection of particles are explained below. Therefore, it may be advantageous to have a V-shaped bottom with collection in the bottom of the V, as shown in Fig. 3.

A typical arrangement for one volume for depositing, is mounted beneath, where there is a raceway of approximately 120m length and a depth of 5m. Flere is used a net weight of water calculated with respect to salinity and temperature. Typical net weight of faeces from fish, is determined at 1150kg/M3. The table below then shows how long time a particle takes to sink down approximately 5m.

We can see from the table that a particle of 0.6mm will use approximately 5.36 min to sink down 5m. In a raceway of 120m length with a water velocity of flow of 5m/s, it will take approximately 4min from the water enters the sedimentation tank to its exit from the sedimentation tank.

When the particles enter the sedimentation tank, they will be evenly distributed. This means that the particles at the top will use the longest time to reach the bottom, while particles distributed downwards in the water mass will use shorter time to reach the bottom of the tank. Based on the table below, the information about density and sinking velocity is used to determine the volume of the sedimentation tank to arrive at good sedimentation for the given velocity of the water in the sedimentation tank.

It is also mentioned that it is possible to have several volumes of water for depositing in such an installation, which may provide further optimization of sedimentation.

Table 1

Objects of the present Invention.

Thus, one object is to provide a solution for through flow and recycling systems which provide energy efficient displacement of the water and flow of the fluid between the two water volumes, i.e. in the first and the second tank, or two sections in the same tank, and that there is also a section or area in the return tank, separated from the fish, which is arranged for sedimentation of particles, and for extraction of particles, so that water cleaned of particles is circulated back to the breeding tank.

Furthermore, it is an object of the invention to provide solutions which make it possible for the fluid in the two fluid volumes to flow at different velocities in the tank’s or tanks’ longitudinal directions. The most important object of the invention is to provide solutions for through flow and recycling systems which effectuate an efficient sedimentation of particles in an area of a given size/density, from the flowing fluid.

Furthermore, it is an object to provide solutions which replace CO2 from CO2 rich fluid with air or oxygen, so that the habitat of the fish is improved. This is carried out by floating units shown in Fig. 5, and by devices 16. These combine creation of current with CO2 aeration and particle removal. These devices 16 exchange gasses dissolved in the water with gasses desired to be added to the water, and they also comprise a device for skimming of the water, i.e., for removal of the smallest particles (size/density smaller than 1mm or 1 2g/cm³). The sedimentation unit or sedimentation tank then provides for sedimentation and removal of some larger particles, in the area of size/density from 1.5 to 1.2mm, so that fluid purified of particles may be returned to the breeding tank or breeding section of the tank. The main purpose of combining sedimenting in a dedicated volume/water reservoir with skimming in separate units, is to obtain removal of particles with all net weights and sizes which emerge in the breeding tank. This means from fodder residues to the smallest particles down to less than 1 urn.

Furthermore, it is an object to provide solutions which reduce the need to pump fluid through the tanks, and where the displacement of fluid from the first tank to the second tank, or between different units of the same tank, takes place at the same time as the exchange of carbon dioxide with oxygen in the fluid.

It is also an object to provide efficient removal of particles from the fluid flowing through the tanks. Summary of the Invention

The present invention relates in a first aspect to a tank system for through flow and recycling solutions for breeding of marine species, characterized in that the tank system comprises two water reservoirs; - a water reservoir which has a water velocity of flow arranged for breeding of marine species, and

- a water reservoir which has a similar or lower water velocity of flow than the velocity of flow in water reservoir, adapted for the depositing/sedimentation of particles of a predetermined size.

In one embodiment, the tank system comprises a device for displacement of fluid between the two water reservoirs.

In one embodiment, the first water reservoir is in a first tank and a second water reservoir is in a second tank, and where fluid flows from the first tank to the second tank and back to the first tank.

In one embodiment, the first tank is placed next to the second tank. In one embodiment, the first tank is placed below the second tank.

In one embodiment, the device for displacement of fluid between the two tanks comprises means for addition of air or oxygen to the fluid and means to establish negative pressure in the device as the fluid is led through the device from the first tank to the second tank above.

In one embodiment, the device comprises a first upstream pipe section for uptake of fluid from the first tank and a second horizontal pipe section arranged to lead the fluid to the second tank and air gasses and remove particles.

In one embodiment, the device creates currents in the second tank by adding fluid from the first tank to the second tank.

In one embodiment, the second tank is arranged floating in the first tank.

In one embodiment, the fluid in the second tank is used to breed marine species, such as fish.

In one embodiment, the first tank is a return tank for circulation and treatment of the water, before it is led to the second tank.

In one embodiment, the first tank is arranged on land.

In one embodiment, both tanks are arranged floating in the sea or a lake.

In one embodiment, the device removes CO2 and small particles from the fluid being led through, and optionally also adds O2 to the fluid which is being led out of the device to the second tank.

In one embodiment, the water reservoir is a sedimentation tank arranged in a bottom section of the tank.

In one embodiment, the tank system is a RAS facility. In one embodiment, a grid, mesh, or seine is arranged to prevent the movement of the marine species to the first tank or sedimentation tank.

In one embodiment, the tank system comprises fixed piping which moves a portion of the fluid from the first tank to the second tank.

In one embodiment, the device is a number of pumps or shovels which together with the device provide displacement of the water.

In one embodiment, there is also in the second tank’s longitudinal direction arranged further devices for the displacement of fluid, exchange of gasses, and removal of particles.

In one embodiment, the devices moving, skimming, and airing CO2 in the tanks, are floating.

In one embodiment, the velocity of flow of the fluid in the first tank is different from the velocity of flow of the fluid in the second tank, preferably so that the velocity of flow is greater in the second tank than in the first tank.

In one embodiment, a channel is arranged in the longitudinal direction of the bottom section of the first tank, and that this channel is arranged for uptake of sediments and particles.

In one embodiment, a perforated hose is placed in this channel, which sucks out the deposits from the return channel.

In one embodiment, a bio-filter is arranged in association with the tank, so that the fluid is being led through this bio-filter before it is added to the second tank.

In one embodiment, the volume in the second tank is several times larger than in the first tank.

In one embodiment, the water reservoir for depositing is closed to, and does not contain, marine organisms being bred.

Description of Figures Preferred embodiments of the invention will in the following be described in greater detail with reference to the attached drawings, where:

Figure 1 shows schematics of a longitudinal flow tank system where two tanks are arranged next to one another, in the longitudinal direction of the tank. In principle, this is one container divided by a separating wall into two tanks.

Figure 2 shows schematics of a longitudinal flow tank system where the second tank is arranged floating in or above the first tank. Figure 3 shows a cross-section schematic of how the second tank is arranged floating in or above the first tank.

Figure 4 shows schematics of an end section of the longitudinal flow tank where there is arranged a device for moving of the fluid from tank 1 and up into tank 2.

Figure 5 shows how a device to exchange CO2 with air or oxygen is arranged floating in the second tank.

Figure 6 shows schematics of a longitudinal flow installation where the two tanks (breeding tank and return tank) are arranged above one another. Figure 6a shows the solution seen from above, and Fig. 6b shows the solution seen from the side. Figure 6c shows the solution in a cross-section where the difference between volume/cross-section of the return tank and the breeding tank (the top one) is evident. Figure 7 shows a schematic of how a separation wall or bottom may be arranged in one tank to establish two water reservoirs. Figure 6a shows the solution seen from above, and the two water reservoirs which are created are laying side by side in the longitudinal direction of the tank. Figure 7b shows the solution from the side, and where it is also schematically indicated how a sedimentation tank with a sedimentation volume is arranged in a bottom section of the tank.

Figure 8 shows schematics of a solution for depositing of particles in a conventional RAS installation where the sedimentation volume of the sedimentation tank makes up the one water reservoir. The fish is prevented from entering into this sedimentation tank, and the water velocity of flow in this sedimentation volume is sufficiently low for particles to sediment to the bottom and may be led out of the tank.

Figure 9 shows schematics of how a sedimentation tank as shown in figure 8 works. The velocity of the water v3 in the sedimentation volume is lower than the velocity of the water v1 in the breeding tank. There is an aperture where the water flows into the sedimentation tank. An adjustable pump may also be used, which controls the amount of water into and out of the sedimentation volume. The breeding tank and the sedimentation volume are divided by a plate or fabric which separate the two water flows and prevent fish from swimming down into the sedimentation volume.

Description of preferred Embodiments of the Invention.

The description below, is as an example based on the solution in Figure 2, i.e., the second tank 12 is arranged floating in or above the first tank 10.

Figure 2 shows how a longitudinal flow tank system 100 is typically constructed. A first tank 10 is typically produced and placed on land. The tank has a longitudinal shape and may typically be 150 meters long and 15 meters wide. The tank 10 is filled with fluid (water or saline water) and floating in tank 10 is then arranged a somewhat smaller second tank 12. The marine species which will be bred, such as fish, occupy the second tank 12, and there are appliances 14 (see Fig. 1 ) such as a mesh or seine which prevent the marine species from moving from the second tank 12 to the first tank 10. Flowever, the water flows between these appliances 14. In the present application, the second tank 12 is also referred to as breeding tank, i.e., it is the tank, or area in a tank 12 occupied by the fish. In this application, the first tank 10 is also referred to as return tank, and while the water flows through this tank 10 the removal of particles is performed.

In Figure 4 is shown a device 16 which moves fluid from the first tank 10 to the second tank 12 and which at the same time exchange gasses in the fluid that is being moved. The device 16 removes CO2 from the fluid flowing through the device 16, and optionally also adds air or O2 to the fluid as it flows through the device 16. Obviously, several such devices 16 may be arranged in the end section of the longitudinal flow tank system 100, or elsewhere in the longitudinal direction of the tank system 100.

The device 16 has an upstream pipe section 16a which extends from the first fluid volume A in the first tank 10 and mainly vertically up to the inlet of the second tank 12. This upstream pipe section 16a is used for intake of fluid to the device 16, and/or transfer of fluid from the return tank 10 to the breeding tank 12.

In a section above the bottom of the second tank 12, then the upstream pipe section 16a in fluid communication with a horizontal pipe section 16b. The horizontal pipe section 16b may in some preferred embodiments have a significant length, so that the fluid is transported a considerable distance.

In a section of the upstream pipe section 16a or in the horizontal pipe section 16b is arranged one or several ejectors 18 which add micro-bubbles of gas, preferably air, to the fluid flowing through the device 16. Micro-bubbles in the water enable good exchange of 02 and C02, as well as skimming of small particles. On the way through the device 16, the water is aired of C02, small particles are removed, it is being oxygenated and the water is also given additional velocity in the second tank 12. Airing tower 20 is connected to fan 22 which provide a certain negative pressure in the device 16 so that waste gasses are removed.

The micro-bubbles being transported through the piping 16 together with the fluid from fluid volume A from the return tank 10 will lead gasses and smaller particles dissolved in fluid volume A to seek out the micro-bubbles. For example, if CO2 is dissolved in the first fluid volume A, then this will be pulled towards the micro-bubbles and may be aired out of the fluid. By the concept “ejector” is meant any addition of a gas into a flow of fluid so that micro-bubbles of gas or air are formed in the fluid. Thus, the concept covers both an “ejector”, based on the gas being passively sucked into the fluid beam (venturi), and an “injector”, based on the injection (pressuring) of something into the fluid/gas flow.

By sufficient addition of air/oxygen via ejector 18 and establishment of sufficient negative pressure with fan 22, the device 16 provides transport and displacement of fluid so that it is possible to reduce the use of pumps, whereby the energy demand is significantly reduced. However, in preferred embodiments of the invention, the device 16 is used together with pumps 24 to flow the fluid from the first tank 10 to the second tank 12.

In one embodiment, the water velocity of flow in the first tank 10 is regulated by the pumping capacity provided by pump 24 together with the capacity of the device 16 which brings the water back to the second tank 12. To achieve an efficient sedimentation of particles in the first tank (the return tank) 10, the water should have a significantly lower water velocity of flow in the first tank 10 than in the second tank 12 where the water velocity of flow is optimized for the species being bred in the tank. As there are no fish creating currents/turbulence in the water in the return tank 10, and as the water velocity of flow in this tank is low (lower than in the breeding tank), particles in the water will sediment and fall to the bottom so that they may be separated out from the tank. This way, the fluid is purified of particles before being recycled back to the breeding tank 10. The return tank, or a sedimentation tank in the return tank, is equipped with a channel 26 for collection of particles deposited down in the fluid. This may for example be a perforated pipe (not shown) where the particles are collected in the pipe, and where means are arranged to extract these particles and remove them from the installation. Particles of sizes all the way down to 0.4mm will then be deposited at the bottom and possible to remove in this manner. The sedimentation at the bottom takes place in a much easier manner in the first tank 10 than in the second tank 12, as the water velocity of flow in the first tank (return tank) 10 may be regulated down, as well as there being no fish in the first tank 10. The fish stir up particles and mitigate the depositing of particles. Particles which are smaller than what is deposited in the first tank 10, i.e., typically particles that are smaller than (0.4mm), will be removed via a skimmer in the device 16 as such small particles often attach to the micro bubbles which are created as the fluid flows through the device 16.

When the water is pumped up again from the first tank 10 to the second tank 12, the water may be driven at great velocity and this way contributes to provide a greater velocity for the water in the breeding tank or section 12. Thus, the velocity of flow in the second tank 12 may be adapted to the marine species being bred in the second tank 12. This way it is possible to separately regulate the water velocity of flow in the two tanks 10 and 12, so that the marine species may occupy water with great flow through velocity, while a lower flow through velocity in the first tank 10 provides good depositing to a channel 26 in the first tank’s 10 longitudinal bottom section.

In addition to there being arranged one or several devices 16 for the displacement of fluid and exchange of gasses in the fluid in the longitudinal direction of the longitudinal flow tank, it is preferred to arrange similar devices 16’ also in the fluid volume in the second tank 12. Such a device 16’ is shown schematically in Figure 4, where it is longitudinal and floats in the second tank 12. This is also illustrated in Figure 5 which schematically shows several such floating devices 16’. The device 16’ is in principle similar to the devices 16 which are arranged in the end sections of the longitudinal flow tank system 100, i.e., there is a piping section (combination of upstream piping section 16a and horizontal piping section 16b) which collect fluid from the first tank 10 and moves the fluid somewhat further downstream in the breeding tank 12. At the same time, the devices 16’ comprise ejectors to add micro- bubbles of air to the fluid, and an airing section in communication with a fan 19 for airing of gasses (such as C02) from the fluid. In this manner, C02 rich fluid is transformed to 02 rich fluid at several positions downward along the longitudinal direction of the first tank 14. Alternatively, to these devices 16’ being arranged floating in the second tank 12, they may be arranged in relation to the longitudinal wall sections of the second tank 12.

In this manner is provided a longitudinal flow tank system 100 and a method for flowing fluid through the two tanks 10 and 12, which makes it possible at the same time to breed fish, where good current is created, and maintain control at the same time of C02, 02, and particles in the water occupied by the fish. As the water is purified of particles, and C02 exchanged for 02, it is possible to reduce the amount of water into and out of the installation and thereby make great savings on energy costs.

When water is reduced into and out of the longitudinal flow tank system 100, one gradually arrives at a level where accumulation of nitrogen compounds (nitrite and nitrate) caused by the ammonium secreted by the fish become critical. If new water in the installation arrives down towards these limiting values, one must add a bio-filter (not shown in figures) in the installation and lead a part of the water flow from the first tank 10 through this before it arrives in the breeding tank 12. Such a bio-filter may also float in the second tank 12, or it may be laying arranged just outside the tank. Figure 6 shows schematics of one presently preferred embodiment of a longitudinal flow tank 100. Here, the tanks 10 and 12 are arranged above one another, with the return tank 10 at the bottom. As in Figure 1 , the longitudinal flow tank system 100 consists in principle only of one tank, and this is separated into two different water reservoirs with a separation wall (phantom bottom) 15 to one breeding tank 12 and one return tank 10. The third figure shows the relationship between the cross-section of the tanks 10 and 12 and shows that the return tank 10 has a greater cross-section/volume than the breeding tank 12. This will lead to reduction of the velocity of the water flowing into the return tank 10, and it is practical that the velocity is sufficiently reduced to obtain and efficient sedimentation of particles before the fluid flows out of the return tank 10 and over into the breeding tank 12. The fish is barred from large sections of the return section with separators 17, for example in the shape of mesh, grid, or seine.

An alternative longitudinal flow tank system 100 is shown in Figure 7. Here, the tanks 10 and 12 are arranged next to one another. The separation wall 15 separates and establishes the two tanks, or two different sections of one tank, and the separators 17 prevent the fish from entering into the return section. The separation wall 15 is impenetrable by water and it may be glided sideways so that the cross-section A1/A2 and B are changed, so that the water velocity of flow in the two tanks, indicated by v1 and v2, are changed so that a much lower water velocity is obtained in return tank 10 than in breeding tank 12. The water velocity of flow in the return tank 10 may thus be reduced according to wish, and the return tank 10 is optimized for depositing of particles of a given size/density.

The bottom figure in Figure 7 also shows a preferred embodiment of a sedimentation chamber 10’ as a recess in the bottom section of the return chamber 10. If the fish is not barred from the return tank in any other way, a separator 17 may be arranged in the bottom of the return tank 10 to prevent the fish from entering the sedimentation chamber 10’. The sedimentation tank 10’ is equipped with an outlet 10a to lead water and particles out of the tank.

In Figure 8 is shown a solution where the sedimentation tank 10’ is equipped with an outlet 10a for water/mud, and an extra outlet 10b for exit of water. This outlet 10b comprises a pump 10c which may regulate the water velocity of flow through the sedimentation tank 10’. Such a sedimentation chamber 11’ with a dedicated pump to control the amount of water in and out of the sedimentation volume, may be used in installations which lack a separate return tank 10, or a separate section of such a return tank. In that case, the fish may be barred from the sedimentation tank 10’ with a separator 19 (plate or fabric). Mud that is deposited and, which remains at the bottom here, may, e.g., be collected by dedicated cleaning robots available in the marketplace, or with a perforated hose arranged in the channel where the mud is sucked out.

Figure 9 illustrates water velocities of flow in the different chambers, or sections of the chambers.

The velocity of the water in the main course is given by v1. The velocity of v4 is mainly regulated by pressure differences at the inlet and outlet of the sedimentation chamber 10’. Pumps that regulate the amount of water circulating in the sedimentation chamber 10’ may also be implemented.

In a raceway solution, the water velocity of flow (v1) may for example be 0.5m/s. This provides a throughput time for the water in a raceway that is approximately 120m long, of approximately 9min/sec (120m + 120m + 15m + 15m). If it is desired that all the water should flow through the sedimentation chamber 10’ every 90 minutes, the velocity will be approximately 5cm/sec in the sedimentation chamber 10’. If then the sedimentation chamber 10’ is 60m long, the water will use 20sec/m x 60m = 1200sec, which equals approximately 20 minutes. If we consider the calculations in table 2 below, where we have a 6m deep sedimentation chamber, we see that particles of the size of 0.4mm will sink from the top to the bottom in 13.22min. A particle of 0.2mm uses approximately 50 minutes. This means that significant amounts of particles will be deposited in the trap. Table 2 - Sinking of Particles in Sedimentation Chamber

Claims

1. Tank system (100) for flow through and recycling solutions for breeding of marine species, characterized in that the tank system (100) comprises two water reservoirs;

- a water reservoir (12) which has a water velocity of flow arranged for breeding of marine species, and

- a water reservoir (10, 10’) which has a similar or lower water velocity of flow than the water velocity of flow in water reservoir (12), adapted for depositing/sedimentation of particles of a predetermined size.

2. Tank system (100) according to claim 1 , characterized in that the tank system (100) comprises a device (16) for movement of fluid between the two water reservoirs (10, 10’ and 12).

3. Tank system (100) according to claim 1 , characterized in that the first water reservoir is in a first tank (10) and a second water reservoir is in a second tank (12), and where fluid flows from the first tank (10) to the second tank (12) and back to the first tank (10).

4. Tank system (100) according to claim 3, characterized in that the first tank (10) lays next to the second tank (12).

5. Tank system (100) according to claim 3, characterized in that the first tank (10) lays below the second tank.

6. Tank system (100) according to claim 3, characterized in that the device (16) for movement of fluid between the two tanks (10, 12) comprises means (18) for addition of air or oxygen to the fluid and means (19) to create negative pressure in the device (16) as the fluid is led through the device (16) from the first tank (10) to the second tank (12) above.

7. Tank system (100) according to claim 3, characterized in that the device (16) comprises a first upstream pipe section (16a) for uptake of fluid from the first tank

(10) and a second horizontal pipe section (16b) arranged to lead the fluid to the second tank (12) and to air gasses and remove particles.

8. Tank system (100) according to claim 3, characterized in that the device (16) creates current in the second tank (12) by leading fluid from the first tank (10) to the second tank (12).

9. Tank system (100) according to claim 3, characterized in that the second tank (12) is arranged floating in the first tank (10). 10. Tank system (100) according to claim 3, characterized in that the fluid in the second tank (12) is used to breed marine species, such as fish.

11. Tank system (100) according to claim 3, characterized in that the first tank (10) is a return tank (10) for circulation and treatment of the water, before it is led to the second tank (12).

12. Tank system (100) according to claim 3, characterized in that the first tank (10) is arranged on land. 13. Tank system (100) according to claim 1 , characterized in that both tanks are arranged floating in the sea or a lake.

14. Tank system (100) according to claim 4, characterized in that the device (16) removes CO2 and small particles from the fluid being led through, and optionally also adds O2 to the fluid being led out of the device (16) to the second tank (12).

15. Tank system (100) according to claim 1 , characterized in that the water reservoir

(10’) is a sedimentation tank (10’) arranged in a bottom section of the tank (100). 16. Tank system (100) according to claim 15, characterized in that the tank (100) is a

RAS facility.

17. Tank system (100) according to any of the preceding claims, characterized in that a grid, mesh, or seine (14) is arranged to prevent the marine species from moving to the first tank (10) or sedimentation tank (10’).

18. Tank system (100) according to claim 4, characterized in that it comprises fixed piping which moves a portion of the fluid from the first tank (10) to the second tank (12).

19. Tank system (100) according to claim 4, characterized in that the device (16) is a number of pumps or shovels (24) which together with the device (16) cause movement of the water.

20. Tank system (100) according to claim 1 , characterized in that also in the longitudinal direction of the second tank (12) further devices (16’) are arranged for movement of fluid, exchange of gasses, and removal of particles. 21. Tank system (100) according to claim 14, characterized in that the devices (16’) which move, skim, and air C02, float in the tanks.

22. Tank system (100) according to claim 3, characterized in that the velocity of flow of the fluid in the first tank (10) is different from the velocity of flow of the fluid in the second tank (12), preferably so that the velocity of flow is greater in the second tank

(12) than in the first tank (10).

23. Tank system (100) according to claim 3, characterized in that in the first tank (10) a channel (26) is arranged in the longitudinal bottom section of the first tank (12), and that this channel (26) is arranged for uptake of sediments and particles.

24. Tank system (100) according to claim 23, characterized in that in this channel (26) lays a perforated hose which sucks out the sediment from the return channel. 25. Tank system (100) according to claim 1 , characterized in that in association with the tank (100) a bio-filter is arranged so the fluid is led through this bio-filter before being added to the second tank (12).

26. Tank system (100) according to claim 1 , characterized in that the volume in the second tank (12) is one to several times larger than the first tank (10).

27. Tank system (100) according to claim 1 , characterized in that the water reservoir (10, 10’) is closed to and does not contain marine organisms being bred.