Aquaponics system

Abstract

To provide an aquaponics system that can reduce salt damage to plants.SOLUTION: A system includes an aquaculture tank 11 in which fish F are raised in water with a higher salinity than fresh water, a filtration tank 12 that nitrifies ammonia contained in aquaculture wastewater W1 discharged from the aquaculture tank 11, a downstream space S1 in which plants P are cultivated using the aquaculture wastewater W1 in which ammonia has been nitrified in the filtration tank 12, and an upstream space S2 in which the plants P are cultivated in diluted aquaculture wastewater W2 with a lower salinity than the water in the downstream space S1. The location of the plants P cultivated in the upstream space S2 is changed to the downstream space S1 depending on the growth status of the plants P.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an aquaponics system technology that combines fish farming and plant cultivation. [Background technology]

[0002] Conventionally, aquaponics system technology that combines fish farming and plant cultivation has been publicly known, as described in Patent Document 1, for example.

[0003] The aquaponics system described in Patent Document 1 includes a breeding tank for cultivating freshwater fish, a plant container for cultivating plants, and a pump for sending raw water from the breeding tank to the plant container. The raw water sent from the breeding tank to the plant container by the pump is purified by a filter bed in the plant container. This breaks down the waste of the freshwater fish, and treated water containing nitric acid, which is a nutrient source for the plants, is generated in the plant container. In the aquaponics system, the plants absorb this nitric acid, and the treated water is returned to the breeding tank, allowing freshwater fish to be cultivated and plants to be grown simultaneously.

[0004] Freshwater fish are cultivated in the breeding tank in Patent Document 1, but if saltwater fish, which are more popular as food than freshwater fish, could be cultivated in the breeding tank, the profitability of the aquaponics system could be improved. However, in this case, it is necessary to cultivate plants in salt water (seawater, artificial seawater, etc.), so if one tries to grow common vegetables (plants with low salt tolerance such as lettuce), there is a possibility that the vegetable production will decrease due to salt damage. For this reason, there is a demand for technology that can reduce the effects of salt damage and improve vegetable production. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6548220 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and the problem to be solved by the present invention is to provide an aquaponics system capable of reducing salt damage to plants. [Means for solving the problem]

[0007] The problem to be solved by the present invention has been described above, and the means for solving this problem will now be described.

[0008] That is, in claim 1, the system comprises an aquaculture tank in which fish are raised in water having a higher salinity than freshwater, a nitrification tank in which ammonia contained in the aquaculture wastewater discharged from the aquaculture tank is nitrified, a first cultivation section in which plants are cultivated using the aquaculture wastewater in which ammonia has been nitrified in the nitrification tank, and a second cultivation section in which plants are cultivated in low-concentration water having a lower salinity than the water in the first cultivation section, and the cultivation location of the plants cultivated in the second cultivation section is changed to the first cultivation section depending on the growth status of the plants.

[0009] In claim 2, the cultivation location of the plant is changed from the second cultivation section to the first cultivation section so that the plant is cultivated in the first cultivation section at least during the harvest season of the plant.

[0010] In claim 3, the plant is moved from the second cultivation section to the first cultivation section as the growth state of the plant progresses.

[0011] In claim 4, the first cultivation section and the second cultivation section are separated from each other by a partition provided in a common aquarium, and the partition is capable of changing its relative position with respect to the aquarium in the direction in which the plant is moved and in the direction opposite to that direction.

[0012] In claim 5, the salinity of the low concentration water is at least higher than the salinity of fresh water.

[0013] In claim 6, the system is configured so that, of the water in the first cultivation section and the low concentration water in the second cultivation section, only the water in the first cultivation section flows into the culture tank.

[0014] In claim 7, the second cultivation section is provided in plurality so that the salt concentrations of the low concentration water are different from each other, and the cultivation location of the plant is changed between the plurality of second cultivation sections and the first cultivation section so that the salt concentration gradually increases as the growth status of the plant progresses.

[0015] In claim 8, the aquaculture wastewater is diluted to store the low concentration water, and the dilution tank is connected to the second cultivation section so as to be able to supply the low concentration water.

[0016] In claim 9, the apparatus further includes a detection unit that detects a water level in the dilution tank, a first switching unit that switches whether or not to supply the aquaculture wastewater to the dilution tank depending on a result of the detection of the water level by the detection unit, and a second switching unit that switches whether or not to supply dilution water for diluting the aquaculture wastewater to the dilution tank depending on a result of the detection of the water level by the detection unit. Effect of the Invention

[0017] The present invention has the following advantages.

[0018] In claim 1, salt damage to plants can be reduced.

[0019] According to claim 2, nitric acid can be efficiently treated.

[0020] In claim 3, the location where the plant is grown can be easily changed.

[0021] According to claim 4, the cultivation periods of the plants in the first cultivation section and the second cultivation section can be easily changed.

[0022] In claim 5, the stress on the plant can be alleviated.

[0023] In claim 6, adverse effects on fish growth can be suppressed.

[0024] According to claim 7, it becomes possible to cultivate plants in water with an appropriate salt concentration according to the growing conditions.

[0025] In claim 8, the aquaculture wastewater can be used to cultivate plants in the second cultivation section.

[0026] According to claim 9, low concentration water can be easily produced according to the water level in the dilution tank. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is an explanatory diagram showing an aquaponics system according to one embodiment of the present invention. [Diagram 2] 1A is a side view showing the aquarium, the moving device, and the growth panel, and FIG. [Diagram 3] FIG. 4 is a side view showing a schematic diagram of the dilution tank, the water level sensor, and the control unit. [Figure 4] 4 is a flowchart showing a dilution tank control process for controlling the dilution tank. [Diagram 5] 1A is a diagram showing a state in which the diluted aquaculture wastewater is stored, and FIG. 1B is a diagram showing a state in which the operation of the second pump is stopped. [Figure 6] (a) A diagram showing the state when fresh water is supplied, and (b) A diagram showing the state when aquaculture wastewater is supplied. [Figure 7] FIG. 13 is an explanatory diagram showing an aquaponics system according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] An aquaponics system 10 according to one embodiment of the present invention will be described below. The aquaponics system 10 simultaneously cultures fish F and plants P. First, an overview of the aquaponics system 10 will be described.

[0029] When cultivating fish F, ammonia contained in excrement of the fish F is harmful to the fish F, and therefore it is necessary to purify the aquaculture wastewater W1 used in cultivating the fish F. Specifically, it is necessary to oxidize the ammonia in the aquaculture wastewater W1 to nitrate and nitrite, and to denitrify the nitrate. Nitrate and the like are substances that are weakly toxic to the fish F, but are nutrients for the plant P. The aquaponics system 10 focuses on this point and replaces the above-mentioned denitrification with the cultivation of the plant P, thereby cultivating the fish F and cultivating the plant P at the same time as purifying the aquaculture wastewater W1 polluted by the cultivation of the fish F. Hereinafter, the configuration of the aquaponics system 10 will be described with reference to Figs. 1 to 3.

[0030] The aquaponics system 10 comprises an aquaculture tank 11, a filtration tank 12, a cultivation tank 13, a moving device 14, a first pump 15, a dilution tank 16, a second pump 17, a water level sensor 18, a first valve 19, a second valve 20 and a control unit 21.

[0031] The culture tank 11 is for raising fish F. In this embodiment, saltwater fish are raised in the culture tank 11. In this case, water suitable for raising saltwater fish is stored in the culture tank 11. For example, the culture tank 11 stores water (natural seawater, artificial seawater, etc.) having a higher salt concentration than freshwater.

[0032] The filtration tank 12 is for filtering the aquaculture wastewater W1. In this embodiment, the filtering includes both physical filtering and biological filtering. The filtration tank 12 is connected to the aquaculture tank 11 via a first pipe K1 so that the aquaculture wastewater W1 discharged from the aquaculture tank 11 flows into the filtration tank 12. The filtration tank 12 can filter impurities contained in the aquaculture wastewater W1 by physical filtering. The filtration tank 12 can also nitrify ammonia contained in the aquaculture wastewater W1 and convert it into nitric acid by biological filtering.

[0033] The cultivation tank 13 is for cultivating plants P. In this embodiment, common vegetables such as lettuce are cultivated in the cultivation tank 13. The plants P cultivated in the cultivation tank 13 are not particularly limited, but are preferably plants P that are suitable for hydroponic cultivation and have relatively high consumer demand. For example, the plants P cultivated in the cultivation tank 13 are preferably leafy vegetables, herbs, tomatoes, etc. By cultivating such plants P, the profitability of cultivating the plants P can be improved.

[0034] 2(a), the cultivation tank 13 includes a water tank 13a capable of storing water. The water tank 13a is provided with a partition plate 13b, a drainage section 13c, and a growth panel 13d.

[0035] The partition plate 13b divides (partitions) the inside of the aquarium 13a. The partition plate 13b is formed, for example, in a plate shape. The partition plate 13b can divide the inside of the aquarium 13a into two spaces. The partition plate 13b of this embodiment is fixed to the aquarium 13a and divides the inside of the aquarium 13a into a downstream space (downstream space S1) and an upstream space (upstream space S2) in the D1 direction. The D1 direction is the direction in which the plant P is moved by the moving device 14 described later.

[0036] 1, the cultivation tank 13 is connected to the filtration tank 12 via a second pipe K2 so that the aquaculture wastewater W1 discharged from the filtration tank 12 flows into the downstream space S1. The cultivation tank 13 is also connected to the dilution tank 16 via a fifth pipe K5 so that water from the dilution tank 16, which will be described later, flows into the upstream space S2.

[0037] The drainage section 13c is for discharging water in the water tank 13a to the outside. When the water level of the water stored in the water tank 13a reaches the position of the drainage section 13c (more specifically, the upper part of the drainage section 13c), the drainage section 13c causes the water to overflow and be discharged to the outside of the water tank 13a. The drainage sections 13c are provided in the downstream space S1 and the upstream space S2, respectively, so that water does not flow between the downstream space S1 and the upstream space S2 beyond the partition plate 13b. The drainage section 13c provided in the downstream space S1 is connected to the aquaculture tank 11 via the third pipe K3. The drainage section 13c provided in the upstream space S2 is connected to the dilution tank 16 via the sixth pipe K6.

[0038] The growth panel 13d shown in Fig. 2 is for supporting a plant P. The growth panel 13d is formed in a plate shape, and is placed above the water tank 13a via a moving device 14 described below. A hole is formed in the growth panel 13d, and the plant P is inserted into the hole. In this way, the growth panel 13d can support the plant P such that the roots of the plant P are immersed in the water in the cultivation tank 13 (enabling the plant P to be grown hydroponically).

[0039] A plurality of growth panels 13d are arranged along the direction D1. The plurality of growth panels 13d support plants P in different growth states. More specifically, the plurality of growth panels 13d support plants P in more advanced growth states as they are arranged downstream in the direction D1.

[0040] As shown in Fig. 2(b), the growth panel 13d supports a plurality of plants P along a direction D2 perpendicular to the direction D1 in a plan view. Note that the water tank 13a is not shown in Fig. 2(b). The plants P arranged in the direction D2 are in the same growth state, unlike the plants arranged in the direction D1.

[0041] The moving device 14 is for moving the growth panel 13d downstream in the D1 direction (from the upstream space S2 to the downstream space S1). The moving device 14 is provided above the water tank 13a and is formed from the upstream end to the downstream end of the water tank 13a in the D1 direction. The growth panel 13d can be placed on the moving device 14. The moving device 14 can also slide the growth panel 13d downstream in the D1 direction. For example, the moving device 14 is configured by a belt conveyor device, and the growth panel 13d can be slid by driving the belt.

[0042] The moving device 14 can move the growth panel 13d from the upstream end to the downstream end in the D1 direction of the aquarium 13a over a predetermined period (e.g., two weeks). Since the partition plate 13b in this embodiment is disposed in the center of the aquarium 13a, the plant P is grown in the upstream space S2 in the first half of the period and in the downstream space S1 in the second half of the period.

[0043] The moving device 14 is not particularly limited in its specific configuration as long as it is used to move the growth panels 13d. For example, the moving device 14 may move each growth panel 13d by pressing the growth panel 13d located at the upstream end in the D1 direction toward the downstream side with a predetermined pressing device, instead of transporting each growth panel 13d by the belt. The moving device 14 may also be a device that manually supports the growth panel 13d so that it can be moved (for example, a roller conveyor without a built-in motor).

[0044] The first pump 15 shown in Fig. 1 is capable of pumping the aquaculture wastewater W1. The first pump 15 is provided in the second pipe K2. Operation of the first pump 15 allows the aquaculture wastewater W1 to circulate between the aquaculture tank 11, the filtration tank 12, and the downstream space S1 of the cultivation tank 13 via the first pipe K1 and the third pipe K3. In this way, the plants P located in the downstream space S1 are cultivated by the aquaculture wastewater W1.

[0045] The dilution tank 16 is for storing water with a low salinity (at least water with a salinity lower than that of the water stored in the downstream space S1). The dilution tank 16 stores water (hereinafter referred to as "diluted aquaculture wastewater W2") obtained by diluting the aquaculture wastewater W1 with dilution water (fresh water in this embodiment). The salt concentration of the diluted aquaculture wastewater W2 is generally a concentration (about 0.3%) at which the plants P are unlikely to suffer salt damage. The salt concentration of the diluted aquaculture wastewater W2 is not particularly limited as long as it is at least lower than that of the water stored in the downstream space S1 (the aquaculture wastewater W1 in this embodiment).

[0046] The dilution tank 16 is connected to the filtration tank 12 via a fourth pipe K4 etc. so that the aquaculture wastewater W1 discharged from the filtration tank 12 flows into the dilution tank 16. The dilution tank 16 is also connected to a freshwater supply source (not shown) via a seventh pipe K7 so that freshwater flows into the dilution tank 16 from the freshwater supply source. In this way, the aquaponics system 10 is configured to be able to dilute the aquaculture wastewater W1 with freshwater in the dilution tank 16.

[0047] 3, a drainage section 16a is provided in the dilution tank 16. When the water level stored in the dilution tank 16 reaches the position of the drainage section 16a (more specifically, the upper part of the drainage section 16a), the drainage section 16a causes the water to overflow and be discharged to the outside of the dilution tank 16.

[0048] The second pump 17 is capable of pumping the diluted aquaculture wastewater W2. As shown in Fig. 1, the second pump 17 is provided in the fifth pipe K5. As described above, the dilution tank 16 is connected to the upstream space S2 of the cultivation tank 13 via the fifth pipe K5 and the sixth pipe K6. Therefore, the operation of the second pump 17 allows the diluted aquaculture wastewater W2 to circulate between the dilution tank 16 and the upstream space S2.

[0049] 3 is for detecting the water level of the dilution tank 16. The water level sensor 18 of this embodiment is configured to detect a minimum water level S11, an operating water level S12, and a maximum water level S13.

[0050] The minimum water level S11 is the maximum water level at which the second pump 17 can operate (without idling). The operating water level S12 is a water level higher than the minimum water level S11. The maximum water level S13 is the maximum water level that can be stored in the dilution tank 16 (the water level at which the diluted aquaculture wastewater W2 is discharged from the drainage section 16a). The maximum water level S13 is higher than the operating water level S12.

[0051] In this embodiment, the operating water level S12 is set according to the dilution ratio of the aquaculture wastewater W1 in the dilution tank 16. Specifically, when the dilution ratio is n, the operating water level S12 is set so that the ratio of the water volume A from the minimum water level S11 to the operating water level S12 to the water volume B from the operating water level S12 to the maximum water level S13 satisfies the relationship of "(n-1):1". More specifically, when the water volume from the minimum water level S11 to the maximum water level S13 is 3 liters and the dilution ratio is 3, the operating water level S12 is set so that the water volume A is 2 liters and the water volume B is 1 liter.

[0052] The water level sensor 18 of this embodiment is a contact-type sensor that can detect the above-mentioned minimum water level S11, etc. Specifically, the water level sensor 18 includes a first electrode 18a, a second electrode 18b, and a third electrode 18c.

[0053] The tip (lower end) of the first electrode 18a is located at the same height as the minimum water level S11 in the dilution tank 16. The tip of the second electrode 18b is located at the same height as the operating water level S12 in the dilution tank 16. The tip of the third electrode 18c is located at the same height as the maximum water level S13 in the dilution tank 16. The water level sensor 18 can detect the minimum water level S11, etc. by detecting that water has come into contact with the tips of the electrodes 18a to 18c.

[0054] As described above, the operating water level S12 is set according to the dilution ratio. Therefore, the position of the tip of the second electrode rod 18b may be adjustable. This makes it possible to easily respond to changes in the dilution ratio of the diluted aquaculture wastewater W2.

[0055] The configuration of the water level sensor 18 is not limited to that of the present embodiment and can be changed as desired. For example, the water level sensor 18 may be a non-contact sensor (such as a laser sensor).

[0056] 1 and 3 is for switching whether or not the aquaculture wastewater W1 is supplied to the dilution tank 16. The first valve 19 is configured by an electromagnetic valve. The first valve 19 is provided in the fourth pipe K4.

[0057] The second valve 20 is for switching whether or not fresh water is supplied to the dilution tank 16. The second valve 20 is configured by an electromagnetic valve. The second valve 20 is provided in the seventh pipe K7.

[0058] The control unit 21 shown in Fig. 3 controls various devices to generate the diluted aquaculture wastewater W2. The control unit 21 includes a calculation unit, a storage unit, etc. The control unit 21 is connected to the second pump 17, etc. so as to enable communication between the second pump 17, the water level sensor 18, the first valve 19, and the second valve 20.

[0059] The control unit 21 can control the operation and stop of the second pump 17 by sending a signal to the second pump 17. The control unit 21 can obtain the detection result of the water level by receiving a signal from the water level sensor 18. The control unit 21 can open and close the fourth pipe K4 and the seventh pipe K7 by sending a signal to the first valve 19 and the second valve 20. The control of various devices by the control unit 21 will be described later.

[0060] In addition to the above-mentioned aquaculture tank 11, etc., the aquaponics system 10 can also include additional equipment necessary for the growth of the fish F and the plants P. For example, it is possible to add equipment for adjusting water temperature, removing protein, and sterilizing, a component adjustment mechanism for adjusting components necessary for the growth of the fish F and the plants P, etc.

[0061] The following describes a procedure for cultivating a plant P in the aquaponics system 10 shown in Fig. 1. A plant P that has reached a predetermined growth stage is transplanted (planted) into the cultivation tank 13 of the aquaponics system 10. For example, a plant P that has reached the planting stage is transplanted into the cultivation tank 13.

[0062] At this time, the plant P is placed on the moving device 14 while being supported by the growth panel 13d, and is arranged at the upstream end of the aquarium 13a in the D1 direction (see FIG. 2(b)). The plant P is gradually moved downstream in the D1 direction by the moving device 14 with its roots immersed in the diluted aquaculture wastewater W2 in the upstream space S2. In this way, the plant P is cultivated in the diluted aquaculture wastewater W2 with a low salt concentration for a predetermined period of time (e.g., one week) after being planted.

[0063] When a predetermined period of time has passed since the plant P was transplanted into the cultivation tank 13, the plant P is moved downstream in the D1 direction (downstream space S1) from the partition plate 13b. The plant P is gradually moved downstream in the D1 direction with its roots immersed in the aquaculture wastewater W1 in the downstream space S1. The plant P thus cultivated in the upstream space S2 is cultivated in the aquaculture wastewater W1 with a high salt concentration for a predetermined period of time (e.g., one week). When the plant P is moved to the downstream end of the aquarium 13a in the D1 direction, it is harvested by an operator or the like.

[0064] According to the aquaponics system 10, the plants P that are relatively undeveloped and have relatively low salt tolerance can be cultivated in the diluted aquaculture wastewater W2. Also, the aquaponics system 10 can return the aquaculture wastewater W1 to the aquaculture tank 11 after the plants P that have grown and become more salt-tolerant absorb nitrate from the aquaculture wastewater W1.

[0065] According to this configuration, even when the culture of saltwater fish is combined with the cultivation of plants P (general vegetables), it is possible to reduce salt damage to the plants P and suppress a decrease in the production volume of the plants P. In addition, it is possible to achieve the objective of aquaponics, which is to cultivate the plants P using the polluted aquaculture wastewater W1 from the culture of fish F.

[0066] It is known that plants P do not absorb much nitrate contained in water until a certain period of time has passed since they were planted. Therefore, even if plants P that are not yet grown are not cultivated in the aquaculture wastewater W1 as in this embodiment, the amount of nitrate absorbed in the cultivation tank 13 does not decrease significantly.

[0067] In this way, by changing the cultivation location of the plant P depending on the growth conditions, the aquaponics system 10 can suppress a decrease in the amount of nitrate absorbed, even when cultivating saltwater fish, and can reduce salt damage to the plant P.

[0068] In this embodiment, the plants P are cultivated in the downstream space S1 from when they are moved to the downstream space S1 until they are harvested (at least during the harvest season). This allows the plants P, which have absorbed a greater amount of nitrate, to absorb the nitrate in the aquaculture wastewater W1, and the nitrate in the aquaculture wastewater W1 can be efficiently treated. This configuration creates an environment that is good for the growth of the fish F and the plants P (an environment in which the nitrate concentration in the aquaculture tank 11 is low and salt damage to the plants P can be reduced), allowing the fish F and the plants P to grow appropriately.

[0069] Here, when the growth panel 13d is moved downstream in the direction D1, an empty space is generated upstream of the moving device 14. A new growth panel 13d supporting a plant P is placed in this space. In this manner, the aquaponics system 10 is configured to add a new plant P to the cultivation tank 13 as the plant P is moved. With this configuration, the plant P can be kept planted in the downstream space S1 and the upstream space S2, so that a large change in the amount of nitrate absorbed due to the movement or harvesting of the plant P can be suppressed, and the nitrate in the aquaculture wastewater W1 can be stably treated (removed).

[0070] In addition, the aquaponics system 10 of this embodiment is configured so that the aquaculture wastewater W1 and the diluted aquaculture wastewater W2 circulate through different routes. Specifically, the aquaponics system 10 is configured so that the aquaculture wastewater W1 circulates through the aquaculture tank 11, the filtration tank 12, and the downstream space S1 shown in Fig. 1, and the diluted aquaculture wastewater W2 circulates through the dilution tank 16 and the upstream space S2. With this configuration, the diluted aquaculture wastewater W2, which has a low salt concentration, does not flow into the aquaculture tank 11, so that a decrease in the salt concentration in the aquaculture tank 11 can be suppressed, and adverse effects on the growth of the fish F can be suppressed.

[0071] Here, the amount of the aquaculture wastewater W1 circulating through the aquaculture tank 11, the downstream space S1, etc., gradually decreases due to evaporation and absorption by the plants P. If the amount of the aquaculture wastewater W1 decreases excessively, for example, the first pump 15 may run idle, causing a water supply problem such as a breakdown. Therefore, the filtration tank 12 of this embodiment is provided with a water supply device (not shown) that can automatically supply water. The water supply device automatically supplies water when, for example, the amount of the aquaculture wastewater W1 decreases, thereby suppressing the occurrence of water supply problems.

[0072] In addition, the amount of the diluted aquaculture wastewater W2 circulating through the dilution tank 16 and the upstream space S2 also gradually decreases due to evaporation, etc. When the amount of the diluted aquaculture wastewater W2 decreases, the control unit 21 shown in Fig. 3 can control the second pump 17 and other devices to generate (add) the diluted aquaculture wastewater W2.

[0073] An example of a process for generating diluted aquaculture effluent W2 will be described below with reference to Fig. 4 to Fig. 6. The flow shown in Fig. 4 is a dilution tank control process for controlling the dilution tank 16 by the control unit 21. The dilution tank control process is started when the cultivation of the plant P is started in the upstream space S2 of the cultivation tank 13, and is continuously executed while the cultivation of the plant P is being performed in the upstream space S2. The control unit 21 generates the diluted aquaculture effluent W2 during the dilution tank control process. A specific description will be given below.

[0074] As shown in Fig. 4, when the control unit 21 starts the dilution tank control process, the process proceeds to step S10. In step S10, the aquaculture wastewater W1 and fresh water are supplied to the dilution tank 16 so as to achieve a predetermined dilution ratio. For example, the aquaculture wastewater W1 and fresh water are supplied by an operator or the like. As a result, the diluted aquaculture wastewater W2 is stored in the dilution tank 16 up to the operating water level S12 (see Fig. 5(a)).

[0075] In addition, the water level of the diluted aquaculture wastewater W2 in step S10 is not limited to this embodiment (operating water level S12) as long as it is at least higher than the minimum water level S11. When the process of step S10 is completed, the control unit 21 proceeds to step S20.

[0076] In step S20, the control unit 21 starts the operation of the second pump 17 that sends the diluted aquaculture wastewater W2 from the dilution tank 16 to the upstream space S2. When the process of step S20 ends, the control unit 21 proceeds to step S30.

[0077] In step S30, the control unit 21 acquires the detection result of the water level of the dilution tank 16 from the water level sensor 18. If the detection result is the minimum water level S11 (step S30: Yes), the control unit 21 proceeds to step S40. On the other hand, if the detection result is not the minimum water level S11 (if it is higher than the minimum water level S11, step S30: No), the control unit 21 proceeds to step S20.

[0078] 4 and 5(b), in step S40, the control unit 21 stops the second pump 17. When the process of step S40 ends, the control unit 21 proceeds to step S50.

[0079] 4 and 6(a), in step S50, the control unit 21 controls the second valve 20 to open, and supplies fresh water to the dilution tank 16. When the process of step S50 ends, the control unit 21 proceeds to step S60.

[0080] In step S60, the control unit 21 obtains the detection result of the water level of the dilution tank 16 from the water level sensor 18. If the detection result is the operating water level S12 (step S60: Yes), the control unit 21 proceeds to step S70. On the other hand, if the detection result is not the operating water level S12 (if it is lower than the operating water level S12, step S60: No), the control unit 21 proceeds again to step S50. In this way, the control unit 21 supplies fresh water until the water level of the dilution tank 16 rises from the minimum water level S11 to the operating water level S12.

[0081] In step S70, the control unit 21 controls the second valve 20 to close, thereby stopping the supply of fresh water. When the process of step S70 ends, the control unit 21 proceeds to step S80.

[0082] 4 and 6(b), in step S80, the control unit 21 controls the first valve 19 to open, and supplies the aquaculture wastewater W1 to the dilution tank 16. When the process of step S80 is completed, the control unit 21 proceeds to step S90.

[0083] In step S90, the control unit 21 obtains the detection result of the water level of the dilution tank 16 from the water level sensor 18. If the detection result is the maximum water level S13 (step S90: Yes), the control unit 21 proceeds to step S100. On the other hand, if the detection result is not the maximum water level S13 (if it is lower than the maximum water level S13, step S90: No), the control unit 21 proceeds to step S80 again. In this way, the control unit 21 supplies the aquaculture wastewater W1 until the water level of the dilution tank 16 rises from the operating water level S12 to the maximum water level S13.

[0084] In step S100, the control unit 21 controls the first valve 19 to close, thereby stopping the supply of the aquaculture wastewater W1. As a result, the diluted aquaculture wastewater W2 is stored in the dilution tank 16 up to the maximum water level S13. In this way, the control unit 21 executes the processes of steps S40 to S100 of the dilution tank control process, thereby adding the diluted aquaculture wastewater W2 to the dilution tank 16. When the process of step S100 is completed, the control unit 21 proceeds to step S110.

[0085] In step S110, if the cultivation of the plant P is continued in the upstream space S2 (step S110: Yes), the control unit 21 proceeds to step S20 and starts the operation of the second pump 17. On the other hand, if the cultivation of the plant P is not continued in the upstream space S2 (step S110: No), the control unit 21 ends the dilution tank control process. Note that in step S110, the control unit 21 can determine whether or not the cultivation of the plant P is continued in the upstream space S2 by checking various information (e.g., a cultivation schedule in the cultivation tank 13, etc.) that can determine whether or not the cultivation of the plant P is continued.

[0086] According to the dilution tank control process, the control unit 21 can easily generate diluted aquaculture effluent W2 simply by controlling the first valve 19 and the second valve 20 according to the water level in the dilution tank 16 (steps S50 to S100).

[0087] Furthermore, according to the dilution tank control process, the control unit 21 can detect a drop in the water level of the dilution tank 16 (step S30), so that the workload of the operator can be reduced.

[0088] Furthermore, in this embodiment, since the diluted aquaculture wastewater W2 can be added up to the maximum water level S13 (steps S50 to S100), the frequency with which the second pump 17 is stopped can be reduced.

[0089] Here, when the water supply device for the filtration tank 12 described above operates, purified water (at least water with a lower nitrate concentration than the diluted aquaculture wastewater W2) is added to the filtration tank 12, so the nitrate concentration of the aquaculture wastewater W1 decreases. Therefore, when the water supply device operates, it is possible to suppress adverse effects on the growth of the fish F. As described above, the water supply device operates when the amount of aquaculture wastewater W1 circulating through the aquaculture tank 11, the filtration tank 12, etc. decreases.

[0090] Therefore, in step S80, the control unit 21 supplies the aquaculture wastewater W1 to the dilution tank 16, thereby reducing the amount of the aquaculture wastewater W1 and making it easier to operate the water supply device. This reduces the nitrate concentration in the aquaculture wastewater W1, and makes it possible to suppress adverse effects on the growth of the fish F.

[0091] As described above, the aquaponics system 10 according to this embodiment includes an aquaculture tank 11 in which fish F are raised in water having a higher salinity than freshwater, a filtration tank 12 (nitrification tank) that nitrifies ammonia contained in the aquaculture wastewater W1 discharged from the aquaculture tank 11, a downstream space S1 (first cultivation section) in which a plant P is cultivated using the aquaculture wastewater W1 in which ammonia has been nitrified in the filtration tank 12, and an upstream space S2 (second cultivation section) in which a plant P is cultivated in diluted aquaculture wastewater W2 (low-concentration water) having a lower salinity than the water (aquaculture wastewater W1) in the downstream space S1, and the cultivation location of the plant P cultivated in the upstream space S2 is changed to the downstream space S1 depending on the growth status of the plant P.

[0092] By configuring in this manner, salt damage to the plant P can be reduced.

[0093] Further, the cultivation location of the plant P is changed from the upstream space S2 to the downstream space S1 so that the plant P is cultivated in the downstream space S1 at least during the harvest season of the plant P.

[0094] By configuring in this way, nitric acid can be efficiently treated.

[0095] As the growth state of the plant P progresses, the plant P is moved from the upstream space S2 toward the downstream space S1.

[0096] With this configuration, the plant P can be easily moved from the upstream space S2 to the downstream space S1 without the need for replanting work.

[0097] In addition, the salinity of the diluted aquaculture effluent W2 is at least higher than the salinity of fresh water.

[0098] With this configuration, when the plant P is moved from the upstream space S2 to the downstream space S1, a large change in the root zone environment (salt concentration) can be suppressed, and the stress applied to the plant P can be alleviated.

[0099] In addition, the aquaponics system 10 is configured such that, of the water in the downstream space S1 (aquaculture wastewater W1) and the diluted aquaculture wastewater W2 in the upstream space S2, only the water in the downstream space S1 flows into the aquaculture tank 11 (see Figure 1).

[0100] By configuring in this manner, adverse effects on the growth of the fish F can be suppressed.

[0101] The aquaponics system 10 further includes a dilution tank 16 that stores the diluted aquaculture wastewater W2 produced by diluting the aquaculture wastewater W1 and is connected to the upstream space S2 so as to be able to supply the diluted aquaculture wastewater W2.

[0102] With this configuration, the aquaculture wastewater W1 can be used to cultivate plants P in the upstream space S2.

[0103] The aquaponics system 10 further includes a water level sensor 18 (detection unit) that detects the water level in the dilution tank 16, a first switching unit (first valve 19 and control unit 21) that switches whether or not to supply the aquaculture wastewater W1 to the dilution tank 16 depending on the water level detection result by the water level sensor 18, and a second switching unit (second valve 20 and control unit 21) that switches whether or not to supply dilution water (fresh water) for diluting the aquaculture wastewater W1 to the dilution tank 16 depending on the water level detection result by the water level sensor 18 (see Figures 5(b) and 6).

[0104] With this configuration, the diluted aquaculture wastewater W2 can be easily generated according to the water level of the dilution tank 16.

[0105] The filtration tank 12 according to this embodiment is one embodiment of the nitrification tank according to the present invention. Moreover, the downstream space S1 according to this embodiment is one embodiment of a first cultivation section according to the present invention. The diluted aquaculture wastewater W2 according to this embodiment is one embodiment of the low-concentration water according to the present invention. Moreover, the upstream space S2 according to this embodiment is one embodiment of a second cultivation section according to the present invention. Moreover, the partition plate 13b according to this embodiment is one embodiment of the partition portion according to the present invention. Moreover, the water level sensor 18 according to this embodiment is one embodiment of a detection unit according to the present invention. Moreover, the first valve 19 and the control unit 21 according to this embodiment are one embodiment of a first switching unit according to the present invention. Moreover, the second valve 20 and the control unit 21 according to this embodiment are one embodiment of a second switching unit according to the present invention.

[0106] Although the embodiment of the present invention has been described above, the present invention is not limited to the above configuration, and various modifications are possible within the scope of the invention described in the claims.

[0107] For example, although saltwater fish are cultured in the culture tank 11, the type of fish F cultured in the culture tank 11 is not limited to saltwater fish. For example, the culture tank 11 may be one in which freshwater fish that can be cultured in water (seawater, artificial seawater, etc.) with a higher salt concentration than freshwater are cultured.

[0108] In the downstream space S1, the plants P are grown in the aquaculture wastewater W1, but the water stored in the downstream space S1 may be water that contains at least the aquaculture wastewater W1 (water that uses the aquaculture wastewater W1). For example, in the downstream space S1, it is also possible to grow the plants P in water that is a mixture of the aquaculture wastewater W1 and other water.

[0109] In addition, in this embodiment, the plant P is cultivated in the cultivation tank 13 from the planting period to the harvest period, but the cultivation period of the plant P in the cultivation tank 13 is not particularly limited and can be changed as desired.

[0110] In this embodiment, the fresh water and the aquaculture wastewater W1 are supplied to the dilution tank 16 by controlling the first valve 19 and the second valve 20, but the method of supplying the fresh water and the aquaculture wastewater W1 is not limited to this embodiment and can be changed as desired. For example, the fresh water and the aquaculture wastewater W1 can be supplied to the dilution tank 16 by controlling a pump provided in the path (the fourth pipe K4 and the seventh pipe K7) through which the fresh water and the aquaculture wastewater W1 flow to the dilution tank 16.

[0111] In the present embodiment, the water with a low salt concentration (low-concentration water) stored in the upstream space S2 is generated using the aquaculture wastewater W1, but the method for generating the low-concentration water is not particularly limited. For example, it is also possible to generate the low-concentration water by diluting salt water different from the aquaculture wastewater W1.

[0112] In the present embodiment, the water tank 13a is divided by the partition plate 13b (plate-shaped member), but the configuration of the partition part for dividing the water tank 13a is not particularly limited and can be changed arbitrarily. For example, the water tank 13a can be divided by a member having a shape other than a plate shape. The partition part (partition plate 13b) is fixed to the water tank 13a, but may be provided so as to be movable relatively to the water tank 13a in the upstream and downstream directions in the D1 direction. For example, the partition part may be configured so as to be movable relatively to the water tank 13a in the upstream and downstream directions in the D1 direction by transmitting power from a driving source such as a motor. This allows the partition part to change the period during which the plant P is cultivated in the aquaculture wastewater W1 and the diluted aquaculture wastewater W2.

[0113] The partition section makes it possible to set an appropriate cultivation period for multiple plant species that have different periods of high salt damage resistance or high nitrate absorption efficiency. For example, when cultivating a plant P that has a relatively long period of high salt damage resistance, the cultivation period can be set so that the period in which the plant is cultivated in the aquaculture wastewater W1 is longer than the period in which the plant is cultivated in the diluted aquaculture wastewater W2. This makes it possible to appropriately cultivate more types of plant P in one cultivation tank 13.

[0114] As described above, the downstream space S1 and the upstream space S2 are separated from each other by a partition plate 13b (partition portion) provided in a common aquarium 13a, and the partition portion is capable of moving relative to the aquarium 13a in the direction in which the plant P is moved and in the opposite direction to that direction. The method of relatively moving the partition is not limited to the above-mentioned driving source, and can be changed as desired. For example, the partition can be moved relatively by changing the attachment part to which the partition is attached, by forming a plurality of attachment parts on the water tank 13a.

[0115] With this configuration, the cultivation period of the plants P in the downstream space S1 and the upstream space S2 can be easily changed.

[0116] In this embodiment, the water tank 13a is divided into two, but the number of divisions into the water tank 13a is not limited to two and can be changed arbitrarily. For example, as shown in Fig. 7, the water tank 13a can be divided into three. In the modification shown in Fig. 7, the water tank 13a is divided into a downstream space S1 in which the aquaculture wastewater W1 is stored, an upstream space S2 in which the diluted aquaculture wastewater W2 is stored, and an intermediate space S3 disposed between the downstream space S1 and the upstream space S2.

[0117] The aquaponics system 10 of the modified example is provided with a dilution tank 116 in addition to the dilution tank 16 of the present embodiment. A first valve 119 that operates independently of the first valve 19 is opened to allow the aquaculture wastewater W1 to flow into the dilution tank 116. A second valve 120 that operates independently of the second valve 20 is opened to allow fresh water to flow into the dilution tank 116. In this manner, the dilution tank 116 is configured to generate diluted aquaculture wastewater W3 having a different dilution ratio from the diluted aquaculture wastewater W2 in the upstream space S2. The dilution tank 116 stores, for example, diluted aquaculture wastewater W3 having a higher salinity than the diluted aquaculture wastewater W2.

[0118] The diluted aquaculture wastewater W3 is stored in the intermediate space S3 via the eighth pipe K8 by the operation of the second pump 117. According to this configuration, the salinity of the water for cultivating the plants P can be gradually increased as the growth state progresses, so that the root zone environment (salinity) of the plants P can be effectively prevented from changing significantly.

[0119] As described above, the second cultivation section is provided in plurality (in FIG. 7, an upstream space S2 and an intermediate space S3 are provided) so that the salt concentrations of the diluted aquaculture wastewater W2 and W3 are different from each other, and the cultivation location of the plant P is changed among the upstream space S2, the intermediate space S3, and the downstream space S1 so that the salt concentration gradually increases as the growth status of the plant P progresses. In the modified example of Fig. 7, the water tank 13a is divided into three sections to form two second cultivation sections, but the water tank 13a may be divided into four or more sections to form three or more second cultivation sections. In this case, by installing one dilution tank less than the number of sections of the water tank 13a, diluted aquaculture effluent with different concentrations can be stored in each second cultivation section.

[0120] By configuring in this manner, it becomes possible to cultivate the plant P in water with an appropriate salt concentration according to the growing conditions. [Explanation of symbols]

[0121] 10. Aquaponics Systems 11 Aquaculture tank 12 Filter tank 14 Moving device F Fish P Plant S1 Downstream space S2 Upstream space W1 Aquaculture drainage W2 Diluted aquaculture drainage

Claims

1. Aquaculture tanks in which fish are raised in water with a higher salt concentration than freshwater; a nitrification tank for nitrifying ammonia contained in the aquaculture wastewater discharged from the aquaculture tank; a first cultivation section for cultivating plants using the aquaculture wastewater in which ammonia has been nitrified in the nitrification tank; A second cultivation section for cultivating plants in low-concentration water having a lower salt concentration than the water in the first cultivation section; Equipped with The cultivation location of the plant cultivated in the second cultivation section is changed to the first cultivation section depending on the growth status of the plant. Aquaponics system.

2. A cultivation location of the plant is changed from the second cultivation section to the first cultivation section so that the plant is cultivated in the first cultivation section at least during a harvest season of the plant.

2. The aquaponics system of claim 1.

3. As the growth status of the plant progresses, the plant is moved from the second cultivation section to the first cultivation section.

3. The aquaponics system according to claim 1 or 2.

4. The first cultivation section and the second cultivation section are They are separated from each other by partitions in a common tank, The partition portion is The water tank is movable relative to the direction in which the plant is moved and in the opposite direction to the direction in which the plant is moved.

4. The aquaponics system of claim 3.

5. The salinity of the low concentration water is At least as saline as freshwater, 3. The aquaponics system according to claim 1 or 2.

6. Of the water of the first cultivation section and the low concentration water of the second cultivation section, only the water of the first cultivation section is configured to flow into the aquaculture tank.

3. The aquaponics system according to claim 1 or 2.

7. The second cultivation section includes: A plurality of low-concentration waters are provided so that the salinities of the low-concentration waters are different from each other, The location of the plant is: The salt concentration is changed between the second cultivation section and the first cultivation section so that the salt concentration gradually increases as the growth state of the plant progresses.

3. The aquaponics system according to claim 1 or 2.

8. The dilution tank further includes a dilution tank in which the dilute water produced by diluting the aquaculture wastewater is stored and which is connected to the second cultivation unit so as to be able to supply the dilute water.

3. The aquaponics system according to claim 1 or 2.

9. A detection unit that detects the water level of the dilution tank; A first switching unit that switches whether or not the aquaculture wastewater is supplied to the dilution tank depending on a detection result of the water level by the detection unit; A second switching unit that switches whether or not to supply dilution water for diluting the aquaculture wastewater to the dilution tank depending on the water level detection result by the detection unit; Further comprising:

9. The aquaponics system of claim 8.

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