Waste liquid utilization system and waste liquid utilization method

Abstract

A waste liquid utilization system that can effectively utilize waste liquid is provided. [Solution] The aquaponics system 10 circulates concentrated water with a higher salt concentration than freshwater between an aquaculture tank 11 where fish are grown and a cultivation tank 12a where plants are grown, and purifies the circulating concentrated water using a water treatment device 13; a hydroponic cultivation device 30 that grows plants using freshwater; and an adjustment tank 50 that mixes a first waste liquid produced in the aquaponics system 10 and a second waste liquid produced by the growth of plants in the second hydroponic cultivation device 30.

Description

[Technical Field]

[0001] The present invention relates to a waste liquid utilization system and a waste liquid utilization method. [Background technology]

[0002] Conventionally, techniques for utilizing wastewater generated during the growth of fish or plants have been publicly known, as described in Patent Document 1, for example.

[0003] The aquaponics system described in Patent Document 1 includes an aquaculture tank for raising fish, a hydroponic cultivation section for growing plants, a physical filtration device, and an anaerobic tank. The aquaponics system is configured so that water circulates in the order of the aquaculture tank, the hydroponic cultivation section, and the physical filtration device. The physical filtration device can filter out solids contained in the water using filter media or the like. The solids are washed away by the water. The water (wastewater) from which the solids have been washed away is introduced into the anaerobic tank. In the anaerobic tank, organic matter contained in the introduced water is decomposed by anaerobic microorganisms, producing sludge. The sludge is supplied to plants. The wastewater produced in this aquaponics system is used as fertilizer.

[0004] Since freshwater fish (sturgeon) are raised in the aquaculture tanks of Patent Document 1, it is believed that freshwater is circulated. If water with a higher salt concentration than freshwater (such as artificial seawater) were circulated in the aquaponics system of Patent Document 1, this highly saline water would be introduced into the anaerobic tank. This would result in sludge with a higher salt content than when freshwater is circulated, which could make it difficult to use as fertilizer. Thus, depending on the type of water circulated, the aquaponics system of Patent Document 1 may not be able to effectively utilize wastewater. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7406776 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 that it aims to solve is to provide a waste liquid utilization system and a waste liquid utilization method that enable effective use of waste liquid. [Means for solving the problem]

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

[0008] That is, in claim 1, the system is provided with a first growth section that circulates concentrated water, which has a higher salt concentration than freshwater, between an aquaculture tank where fish are grown and a cultivation tank where plants are grown, and purifies the circulating concentrated water in a purification section, a second growth section that grows plants using freshwater, and a mixing section that mixes the first waste liquid produced in the purification section and the second waste liquid produced by the growth of plants in the second growth section.

[0009] In claim 2, the plant growing apparatus further comprises a third growing section for growing plants using fertilizer made from the waste liquid mixed in the mixing section.

[0010] In claim 3, the ratio at which the first waste liquid and the second waste liquid are mixed in the mixing section is set according to the plants grown in the third growing section.

[0011] In claim 4, the purification unit is equipped with a foam separation unit that removes foam generated in the high-concentration water, thereby removing adsorbed substances adsorbed to the foam along with the foam, and the first waste liquid contains the foam removed in the foam separation unit.

[0012] In claim 5, the apparatus further comprises a first reservoir for storing the first waste liquid.

[0013] In claim 6, the device further comprises a second storage section for storing the second waste liquid, and further comprises a sterilization section for sterilizing at least one of the first waste liquid stored in the first storage section or the second waste liquid stored in the second storage section.

[0014] In claim 7, the system further comprises an adjusting section that adjusts at least one of the amount of the first waste liquid supplied from the purification section to the mixing section or the amount of the second waste liquid supplied from the second growth section to the mixing section.

[0015] In claim 8, the apparatus further comprises a cleaning water supply unit capable of sending out cleaning water for cleaning the purification unit, and the cleaning water that has cleaned the purification unit is introduced into the mixing unit.

[0016] In claim 9, the system includes a first growth process in which concentrated water, which has a higher salt concentration than freshwater, is circulated between an aquaculture tank in which fish are grown and a cultivation tank in which plants are grown, and the circulating concentrated water is purified in a purification unit; a second growth process in which plants are grown using freshwater; and a mixing process in which the first waste liquid produced in the purification unit and the second waste liquid produced by the growth of plants in the second growth process are mixed. [Effects of the Invention]

[0017] The present invention has the following effects.

[0018] According to claim 1, the waste liquid can be effectively utilized.

[0019] In claim 2, the waste liquid can be used for growing plants.

[0020] In claim 3, the first waste liquid and the second waste liquid can be mixed to have a component concentration that can promote plant growth in the third growth section.

[0021] In claim 4, the adsorbed matter removed in the foam separation section can be effectively utilized.

[0022] According to claim 5, the solid content can be easily removed.

[0023] According to claim 6, deterioration of water quality caused by storing the first waste liquid or the second waste liquid can be suppressed.

[0024] In claim 7, convenience can be improved.

[0025] According to claim 8, washing water can be effectively utilized.

[0026] According to claim 9, the waste liquid can be effectively utilized. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is an explanatory diagram showing a waste liquid utilization system according to a first embodiment of the present invention; [Figure 2] FIG. 2 is an explanatory diagram showing the water treatment device and the hydroponic cultivation device in detail. [Figure 3] FIG. 1 is an elevation view showing the waste liquid utilization system. [Figure 4] Elevation showing the aquaponics system. [Figure 5] FIG. [Figure 6] 1 is a flowchart showing a procedure for storing liquid fertilizer using a waste liquid utilization system. [Figure 7] FIG. 1 is an explanatory diagram showing a waste liquid utilization system provided with a sterilization device. [Figure 8] FIG. 10 is an explanatory diagram showing a waste liquid utilization system according to a second embodiment. [Figure 9] Also, the elevation view. DETAILED DESCRIPTION OF THE INVENTION

[0028] A waste liquid utilization system 1 according to a first embodiment of the present invention will be described below. The waste liquid utilization system 1 is for utilizing waste liquid generated in an aquaponics system 10. First, an overview of the waste liquid utilization system 1 will be described with reference to FIG.

[0029] The aquaponics system 10 is a system that combines hydroponics and fish farming to allow hydroponic plants to absorb nutrients (such as nitrogen) produced by the fish farming, thereby purifying water while the plants grow. The aquaponics system 10 is configured such that water with a higher salt concentration than freshwater (natural seawater, artificial seawater, etc., hereinafter referred to as "high-concentration water") circulates between a fish farming tank 11 for growing fish and a cultivation device 12 for growing plants. In the fish farming tank 11, saltwater fish are cultivated using the high-concentration water. In the cultivation device 12, hydroponic cultivation is carried out using the high-concentration water. The salinity of the high-concentration water is adjusted to a range that allows the fish in the fish farming tank 11 and the plants in the cultivation device 12 to grow. For example, the salinity of the high-concentration water is adjusted to be higher than that of freshwater but lower than that of seawater.

[0030] The highly concentrated water circulating between the culture tank 11 and the cultivation device 12 is purified in the water treatment device 13. In addition, the waste liquid and sludge generated when purifying the highly concentrated water are discharged to the outside of the aquaponics system 10 (first waste liquid tank 20). Hereinafter, the waste liquid and sludge discharged from the aquaponics system 10 will be referred to as the "first waste liquid."

[0031] Because the first waste liquid contains a large amount of plant nutrients (potassium, calcium, magnesium, etc.), if the first waste liquid is used as fertilizer, the highly concentrated water can be reused. However, because the first waste liquid has a high salt concentration, if the first waste liquid is used as fertilizer, the salt concentration of the first waste liquid must be reduced to a level that can prevent salt damage.

[0032] Therefore, in the waste liquid utilization system 1, the first waste liquid is diluted with waste liquid having a lower salt concentration than the first waste liquid. More specifically, the first waste liquid is diluted with waste liquid generated by hydroponic cultivation using freshwater. The diluted first waste liquid is applied to plants as fertilizer, and the waste liquid utilization system 1 is configured to utilize two waste liquids together. Hereinafter, the waste liquid generated by hydroponic cultivation using freshwater will be referred to as the "second waste liquid." The configuration of the waste liquid utilization system 1 will be described below.

[0033] As shown in FIGS. 2 and 3, the waste liquid utilization system 1 includes an aquaponics system 10, a first waste liquid tank 20, a hydroponic cultivation device 30, a second waste liquid tank 40, an adjusting tank 50, and a hydroponic cultivation device 60.

[0034] The aquaponics system 10 is a system that combines hydroponic cultivation and fish farming. The aquaponics system 10 includes a culture tank 11, a cultivation device 12, and a water treatment device 13.

[0035] The aquaculture tank 11 is used to raise fish (saltwater fish) in concentrated water. The concentrated water is stored in the aquaculture tank 11. As shown in FIG. 4, the aquaculture tank 11 is connected to a filtration tank 13a of a water treatment device 13 (described later) via two pipes K1 and K2. The concentrated water is introduced from the filtration tank 13a to the aquaculture tank 11 via the pipe K1. The concentrated water is also introduced from the aquaculture tank 11 to the filtration tank 13a via the pipe K2. In this embodiment, when the water level in the aquaculture tank 11 reaches a predetermined height, the concentrated water overflows via the pipe K2 and is introduced into the filtration tank 13a.

[0036] The cultivation device 12 shown in Figures 2 and 3 is for performing hydroponic cultivation using highly concentrated water. The cultivation device 12 includes a cultivation tank 12a (see Figure 3) in which highly concentrated water is stored. Plants are planted in the cultivation tank 12a so that their roots are immersed in the highly concentrated water. In this way, the plants are grown in the cultivation tank 12a by hydroponic cultivation. The cultivation device 12 is connected to a filtration tank 13a via two pipes (not shown), similar to the aquaculture tank 11. The cultivation device 12 is also configured so that highly concentrated water can be appropriately circulated between the cultivation device 12 and the filtration tank 13a. For example, the cultivation device 12 is configured so that highly concentrated water can be circulated between the cultivation device 12 and the filtration tank 13a by a pump or the like.

[0037] The water treatment device 13 is for purifying the highly concentrated water. The water treatment device 13 is disposed between the culture tank 11 and the cultivation device 12 (see FIG. 2). The water treatment device 13 includes a filtration tank 13a and a foam separator 13b.

[0038] The filtration tank 13a filters the concentrate water and adjusts its components. In this embodiment, the filtration includes both physical filtration and biological filtration. The filtration tank 13a can filter impurities contained in the concentrate water through physical filtration. The filtration tank 13a can also nitrify ammonia contained in the concentrate water and convert it into nitric acid and the like through biological filtration. Since nitric acid and the like are nutrients for plants, they are absorbed by the plants in the cultivation device 12. In this way, the aquaponics system 10 can suppress an increase in the concentration of nitric acid and the like, which are weakly toxic to fish, and can grow both fish and plants at the same time.

[0039] The foam separator 13b is a device that purifies concentrated water by utilizing the property of contaminants being adsorbed by foam. The foam separator 13b is equipped with a tank (not shown) that can store concentrated water. As shown in FIG. 4, the foam separator 13b is connected to the filtration tank 13a via two pipes K3 and K4. Of these, the pipe K3 is provided with a pump 13c. When the pump 13c is driven, concentrated water is introduced into the foam separator 13b (tank) from the filtration tank 13a via the pipe K3.

[0040] The foam separator 13b can generate foam in the concentrate water from the filtration tank 13a. Contaminants are adsorbed to the foam. By removing the foam, the foam separator 13b can remove the adsorbed matter adsorbed to the foam along with the foam, thereby purifying the concentrate water. The foam separator 13b can also return the purified concentrate water to the filtration tank 13a via pipe K4. Note that the adsorbed matter removed along with the foam by the foam separator 13b may contain substances other than contaminants. For example, the adsorbed matter may include trace metals (iron, copper, zinc, manganese, molybdenum, boron, chlorine, nickel), etc.

[0041] The aquaponics system 10 is configured so that concentrate is circulated between the aquaculture tank 11 and the cultivation device 12 via pipes K1 and K2, etc. A pump (e.g., pump 14 shown in FIG. 4 ) is provided in the circulation path of the concentrate, and when the pump is driven, the concentrate flows from the cultivation device 12 to the aquaculture tank 11 through the water treatment device 13, as shown in FIG. 2 . The concentrate also flows from the aquaculture tank 11 to the cultivation device 12 through the water treatment device 13. In this manner, in this embodiment, the concentrate passes through the water treatment device 13 in both the circulation path from the cultivation device 12 to the aquaculture tank 11 and the circulation path from the aquaculture tank 11 to the cultivation device 12. As described above, in this embodiment, the concentrate flows from the aquaculture tank 11 to the filtration tank 13a by overflow, so that the number of pumps required to circulate the concentrate can be reduced.

[0042] The circulation path of the concentrate is not limited to that of the present embodiment, as long as the concentrate passes through the water treatment device 13 at least once when circulating between the aquaculture tank 11 and the cultivation device 12. For example, the concentrate may be configured to circulate through the water treatment device 13 in either the circulation path from the cultivation device 12 to the aquaculture tank 11 or the circulation path from the aquaculture tank 11 to the cultivation device 12.

[0043] Here, the concentrated water passes through the water treatment device 13 and is purified in the filtration tank 13a and the foam separator 13b. At this time, foam is removed in the foam separator 13b. Waste liquid containing the foam (foam separated liquid) and sludge generated by the purification of the concentrated water are discharged to the outside of the aquaponics system 10. In this embodiment, the waste liquid, etc. is discharged to the first waste liquid tank 20 via the pipe K5 shown in FIG. 4. More specifically, the waste liquid, etc. overflows from the foam separator 13b via the pipe K5 and is discharged to the first waste liquid tank 20. In this embodiment, the waste liquid, etc. is the first waste liquid discharged from the aquaponics system 10.

[0044] The first waste liquid tank 20 stores the first waste liquid. As shown in FIG. 5 , the first waste liquid tank 20 is connected to the adjustment tank 50 (described later) via a pipe K6. In this embodiment, the first waste liquid tank 20 can distribute the first waste liquid to the adjustment tank 50 by overflowing. For example, the first waste liquid tank 20 can be disposed at a higher position than the adjustment tank 50 or formed with a shape that is vertically longer than the adjustment tank 50, thereby causing the first waste liquid to overflow via the pipe K6 and distribute the first waste liquid to the adjustment tank 50. In this way, the first waste liquid in this embodiment distributes from the foam separator 13b to the first waste liquid tank 20 and the adjustment tank 50 by overflowing. With this configuration, the number of pumps required to distribute the first waste liquid can be reduced.

[0045] Here, the first waste liquid stored in the first waste liquid tank 20 may contain solid content (for example, solid contaminants). By storing the first waste liquid in the first waste liquid tank 20, the solid content can be separated and removed. For example, if the solid content precipitates, the solid content can be removed by precipitation.

[0046] Furthermore, the pipe K6 is provided with a valve 21, and by adjusting the opening of the valve 21, the amount of the first waste liquid supplied from the first waste liquid tank 20 to the adjustment tank 50 can be adjusted.

[0047] The hydroponic cultivation device 30 is for growing plants by hydroponic cultivation using fresh water. The hydroponic cultivation device 30 includes a cultivation tank 31 and a nutrient solution tank 32.

[0048] The cultivation tank 31 is used to cultivate plants. The same type of plants as those in the cultivation tank 12a are grown in the cultivation tank 31. The plants in the cultivation tank 31 are less advanced in growth than the plants in the cultivation tank 12a. More specifically, plants in the seedling stage are grown in the cultivation tank 31, while plants that have completed the seedling stage are grown in the cultivation tank 12a. A freshwater nutrient solution is stored in the cultivation tank 31. The freshwater nutrient solution is a liquid in which fertilizer is dissolved in freshwater. Plants are planted in the cultivation tank 31 so that their roots are immersed in the freshwater nutrient solution.

[0049] The nutrient solution tank 32 is used to adjust the nutrient components of the freshwater nutrient solution. The nutrient solution tank 32 stores the freshwater nutrient solution. The nutrient solution tank 32 is connected to the cultivation tank 31 via two pipes K7 and K8. The nutrient solution tank 32 is also provided with a pump 33. When the pump 33 is driven, the freshwater nutrient solution in the nutrient solution tank 32 is introduced into the cultivation tank 31 via the pipe K7. The freshwater nutrient solution in the cultivation tank 31 is also introduced into the nutrient solution tank 32 via the pipe K8. In this way, in the hydroponic cultivation device 30, the freshwater nutrient solution is circulated between the nutrient solution tank 32 and the cultivation tank 31, allowing plants to grow.

[0050] In this embodiment, plants are grown in the hydroponic cultivation device 30 until the end of the seedling raising period. The plants are then transplanted into the aquaponics system 10 (cultivation tank 12a). This makes it possible to suppress the occurrence of salt damage.

[0051] Specifically, plants in the seedling stage have relatively low salt tolerance because they are not yet fully grown. On the other hand, plants that have completed the seedling stage have relatively high salt tolerance because they have progressed in growth. Therefore, in this embodiment, plants that have been grown in the cultivation tank 31 (freshwater) until the end of the seedling stage are transplanted into the aquaponics system 10 and grown in highly concentrated water. This allows plants to be grown in water (salt concentration) appropriate for their salt tolerance, thereby suppressing the occurrence of salt damage in the aquaponics system 10.

[0052] Since continued use of the freshwater nutrient solution will deteriorate the water quality, the hydroponic cultivation device 30 is configured to be able to replace the freshwater nutrient solution. In this embodiment, the hydroponic cultivation device 30 is configured to be able to replace the freshwater nutrient solution using the pipe K9, the first valve 34, and the second valve 35.

[0053] Specifically, the pipe K9 guides the freshwater nutrient solution from the cultivation tank 31 to the second waste liquid tank 40. The pipe K9 is connected to the cultivation tank 31 via the pipe K8, which guides the freshwater nutrient solution from the cultivation tank 31 to the nutrient solution tank 32. The first valve 34 switches whether or not the freshwater nutrient solution flows from the cultivation tank 31 to the second waste liquid tank 40. The first valve 34 is provided on the pipe K9. The second valve 35 switches whether or not the freshwater nutrient solution flows from the cultivation tank 31 to the nutrient solution tank 32. The second valve 35 is provided on the pipe K8.

[0054] By closing the first valve 34 and opening the second valve 35, the hydroponic cultivation device 30 is switched to a first state in which the freshwater nutrient solution can circulate between the cultivation tank 31 and the nutrient solution tank 32. In this state, the pump 33 is driven to circulate the freshwater nutrient solution, and the plants in the cultivation tank 31 are grown.

[0055] Furthermore, by opening the first valve 34 and closing the second valve 35, the hydroponic cultivation device 30 is switched to a second state in which the freshwater nutrient solution can be discharged to the second waste liquid tank 40. The hydroponic cultivation device 30 is switched to the second state, for example, when a plant in the cultivation tank 31 is transplanted into the aquaponics system 10. By driving the pump 33 in this state, the freshwater nutrient solution is discharged from the cultivation tank 31 to the second waste liquid tank 40. This freshwater nutrient solution is the second waste liquid generated by the growth of plants in the hydroponic cultivation device 30. After the freshwater nutrient solution is discharged, the cultivation tank 31 and the nutrient solution tank 32 are replenished with new freshwater nutrient solution. In this manner, the freshwater nutrient solution is replaced.

[0056] The second waste liquid tank 40 stores the second waste liquid. The second waste liquid tank 40 is connected to the adjustment tank 50 via a pipe K10. In this embodiment, a pump 41 is provided in the second waste liquid tank 40, and the second waste liquid can be introduced into the adjustment tank 50 by driving the pump 41. Furthermore, the amount of second waste liquid supplied to the adjustment tank 50 can be adjusted by adjusting the discharge rate of the pump 41.

[0057] 2 and 3 is for mixing the first waste liquid and the second waste liquid. In the adjustment tank 50, the first waste liquid and the second waste liquid are mixed at a ratio according to the plants to be grown in the hydroponic cultivation device 60 described below. For example, the first waste liquid and the second waste liquid are mixed at a ratio that results in a component concentration suitable for the growth of the plants.

[0058] By mixing the first waste liquid generated from the high-concentration water with the second waste liquid generated from fresh water in this way, the first waste liquid, which has a high salt concentration, is diluted with the second waste liquid, thereby lowering the salt concentration of the first waste liquid. In the adjustment tank 50, this first waste liquid with a reduced salt concentration is stored as liquid fertilizer.

[0059] Here, it is assumed that the components of the waste liquids (first waste liquid and second waste liquid) will fluctuate due to various factors. For example, the salinity of the concentrated water fluctuates when circulating through the aquaponics system 10, and the fluctuation in salinity causes the salinity of the waste liquid (first waste liquid) to fluctuate. Furthermore, various waste liquids with different salinity concentrations (foam separation liquid, waste liquid containing sludge, etc.) are collected in the adjustment tank 50. It is assumed that the amount (ratio) of the waste liquids is not constant, so the salinity of the waste liquids will fluctuate depending on the amount of the waste liquid.

[0060] Therefore, in this embodiment, the mixing ratio of the first waste liquid and the second waste liquid is appropriately changed in accordance with fluctuations in the components of the waste liquid. More specifically, a target value of the salt concentration is set in accordance with the plants to be grown in the hydroponic cultivation device 60, and then the mixing ratio of the first waste liquid and the second waste liquid is determined in accordance with the component concentrations of the waste liquid introduced into the adjusting tank 50 (mainly the salt concentrations of the first waste liquid and the second waste liquid). At this time, the mixing ratio is determined (changed) so as to achieve the target value. In this way, the first waste liquid and the second waste liquid can be mixed so as to have component concentrations suitable for the growth of the plants, regardless of fluctuations in the components of the waste liquid.

[0061] The above-described method for setting the mixing ratio is an example and can be changed as appropriate. For example, when the components of the waste liquid are stable, the mixing ratio of the first waste liquid and the second waste liquid does not need to be changed according to fluctuations in the components of the waste liquid. In this case, the first waste liquid and the second waste liquid are mixed at a fixed ratio (for example, a 1:1 ratio) regardless of fluctuations in the components of the waste liquid.

[0062] Incidentally, tap water can be introduced into the adjustment tank 50 as needed. For example, when there is a shortage of the second waste liquid, tap water is introduced into the adjustment tank 50, and the first waste liquid, the second waste liquid, and the tap water are mixed together. Furthermore, fertilizer can be introduced into the adjustment tank 50 as needed. For example, when there is a shortage of a component (such as potassium) contained in the first waste liquid that is necessary for plant growth, fertilizer is introduced into the adjustment tank 50 to supplement the component, and the first waste liquid, the second waste liquid, and the fertilizer are mixed together.

[0063] As shown in FIG. 3, the adjusting tank 50 is provided with a pump 51, and the liquid fertilizer produced in the adjusting tank 50 is introduced into the hydroponics device 60 by driving the pump 51.

[0064] The hydroponics device 60 grows plants using liquid fertilizer (diluted first waste liquid) stored in the adjustment tank 50. Relatively salt-tolerant plants are grown in the hydroponics device 60. For example, plants that can grow in water with a higher salt concentration than freshwater but a lower salt concentration than seawater are grown. In this embodiment, tomatoes are grown. In the hydroponics device 60, tomatoes are planted in a medium such as rock wool (not shown). The liquid fertilizer introduced from the adjustment tank 50 to the hydroponics device 60 is supplied to the tomatoes. For example, the liquid fertilizer is supplied to the tomatoes by drip irrigation.

[0065] In this embodiment, by supplying liquid fertilizer to plants (tomatoes), the nutrients contained in high concentrations in the highly concentrated water (first waste liquid) can be utilized for plant growth. Furthermore, since the liquid fertilizer is a mixture of the first and second waste liquids, the two waste liquids can be used together for plant growth, enabling effective utilization of the waste liquids. In particular, the first waste liquid (which is difficult to use) generated in the aquaponics system 10 can be effectively utilized without being discarded.

[0066] As described above, the first waste liquid contains foam removed by the foam separator 13b. Trace metals (such as iron) contained in the concentrated water may be adsorbed to the foam. The trace metals are nutrient components for plants. Therefore, when trace metals are adsorbed to the foam by the foam separator 13b, liquid fertilizer containing the trace metals can be supplied to the plants in the hydroponic cultivation device 60, thereby supplying the plants with the trace metals and promoting their growth.

[0067] The following describes an example of a procedure (a waste liquid utilization method) for storing liquid fertilizer using the waste liquid utilization system 1. As shown in Fig. 6, when storing liquid fertilizer, a first growth step S10, a second growth step S20, and a dilution step S30 are performed.

[0068] The first growing step S10 is a step of growing saltwater fish and plants in the high-concentration water (aquaponics system 10). In the first growing step S10, the first wastewater discharged from the foam separator 13b is stored in the first wastewater tank 20 (see FIG. 2). The foam separator 13b continuously purifies the high-concentration water, for example, while the aquaponics system 10 is in operation. In this case, a certain amount of the first wastewater is stored in the first wastewater tank 20 at any time.

[0069] The second growing step S20 is a step of growing plants in freshwater (hydroponic cultivation device 30). In the second growing step S20, the second waste liquid (freshwater nutrient solution) is stored in the second waste liquid tank 40 at the timing when the plants in the cultivation tank 31 are transplanted into the aquaponics system 10.

[0070] The dilution step S30 is a step of diluting the first waste liquid in the adjustment tank 50. The dilution step S30 is performed at least in a state in which the first waste liquid can be supplied from the first waste liquid tank 20 to the adjustment tank 50 by overflow. In the present embodiment, the dilution step S30 is performed when the water level in the first waste liquid tank 20 is at a level that allows the first waste liquid to overflow and after the second waste liquid has been stored in the second waste liquid tank 40 in the second growth step S20.

[0071] In the dilution step S30, the first waste liquid is introduced into the adjustment tank 50 from the first waste liquid tank 20, and the second waste liquid is introduced into the adjustment tank 50 from the second waste liquid tank 40. The adjustment tank 50 mixes the introduced first waste liquid and second waste liquid. By performing the dilution step S30, liquid fertilizer obtained by diluting the first waste liquid with the second waste liquid can be stored in the adjustment tank 50.

[0072] In the above-described procedure, the first waste liquid and the second waste liquid are mixed after the second waste liquid is stored in the second waste liquid tank 40, so that the second waste liquid is less likely to run short in the dilution step S30.

[0073] The dilution step S30 may be performed at a different timing than in this embodiment. For example, the dilution step S30 may be performed before the second waste liquid is stored in the second waste liquid tank 40. In this case, the adjustment tank 50 can dilute the first waste liquid with a liquid other than the second waste liquid (e.g., tap water). This allows, for example, even if there is a shortage of the second waste liquid when liquid fertilizer is to be supplied to plants in the hydroponic cultivation device 60, liquid fertilizer obtained by diluting the first waste liquid can be supplied to the plants. Furthermore, it is possible to prevent the first waste liquid from overflowing from the first waste liquid tank 20.

[0074] When the first waste liquid and the second waste liquid are stored, there is a concern that the water quality may deteriorate. For this reason, it is possible to sterilize at least one of the first waste liquid and the second waste liquid (to perform a sterilization step).

[0075] 7, it is also possible to sterilize the second waste liquid by disposing a sterilization device 70 in the path through which the second waste liquid flows from the second waste liquid tank 40 to the adjustment tank 50. The sterilization device 70 can sterilize the second waste liquid, for example, by irradiating the second waste liquid with ultraviolet light or supplying ozone to the second waste liquid.

[0076] The sterilization device 70 may be disposed in the path through which the first waste liquid flows from the first waste liquid tank 20 to the adjustment tank 50. This allows the first waste liquid to be sterilized. The sterilization device 70 may be disposed both in the path through which the second waste liquid flows from the second waste liquid tank 40 to the adjustment tank 50 and in the path through which the first waste liquid flows from the first waste liquid tank 20 to the adjustment tank 50. This allows both the first waste liquid and the second waste liquid to be sterilized.

[0077] As described above, the waste liquid utilization system 1 of this embodiment circulates concentrated water, which has a higher salt concentration than fresh water, between the aquaculture tank 11 where fish are grown and the cultivation tank 12a where plants are grown, and is equipped with an aquaponics system 10 (first growth section) that purifies the circulating concentrated water in a water treatment device 13 (purification section), a hydroponic cultivation device 30 (second growth section) that grows plants using fresh water, and an adjustment tank 50 (mixing section) that mixes the first waste liquid produced in the aquaponics system 10 and the second waste liquid produced by the growth of plants in the hydroponic cultivation device 30.

[0078] By configuring in this way, it is possible to effectively utilize the waste liquid.

[0079] The waste liquid utilization system 1 further includes a hydroponic cultivation device 60 (third growing section) for growing plants using fertilizer made from the waste liquid mixed in the adjusting tank 50.

[0080] By configuring it in this way, the waste liquid can be used for the growth of plants.

[0081] The ratio at which the first waste liquid and the second waste liquid are mixed in the adjusting tank 50 is set according to the plants to be grown in the hydroponic cultivation device 60.

[0082] By configuring in this way, the first waste liquid and the second waste liquid can be mixed to have a component concentration that can promote the growth of plants in the nutrient solution cultivation device 60.

[0083] In addition, the water treatment device 13 is equipped with a foam separator 13b (foam separation section) that removes foam generated in the high-concentration water, thereby removing adsorbed substances adsorbed to the foam along with the foam, and the first waste liquid contains the foam removed by the foam separator 13b.

[0084] This configuration allows for effective use of the adsorbed matter removed by the foam separator 13b. For example, if trace metals are adsorbed to the foam, liquid fertilizer can be generated from the trace metals and supplied to plants to promote their growth.

[0085] The waste liquid utilization system 1 further includes a first waste liquid tank 20 (first storage section) for storing the first waste liquid.

[0086] With this configuration, the solid content contained in the first waste liquid can be separated in the first waste liquid tank 20.

[0087] In addition, the waste liquid utilization system 1 further includes a second waste liquid tank 40 (second storage section) for storing the second waste liquid, and further includes a sterilization device 70 (sterilization section) for sterilizing at least one of the first waste liquid stored in the first waste liquid tank 20 or the second waste liquid stored in the second waste liquid tank 40.

[0088] With this configuration, it is possible to suppress deterioration of water quality that may occur when the first waste liquid or the second waste liquid is stored.

[0089] In addition, the waste liquid utilization system 1 further includes an adjustment unit (valve 21, pump 41) that adjusts at least one of the amount of the first waste liquid supplied from the water treatment device 13 to the adjustment tank 50 or the amount of the second waste liquid supplied from the hydroponic cultivation device 30 to the adjustment tank 50.

[0090] With this configuration, the mixing ratio of the first waste liquid and the second waste liquid can be adjusted, thereby improving convenience.

[0091] As described above, the waste liquid utilization method according to this embodiment includes a first growth step S10 in which concentrated water having a higher salt concentration than water is circulated between the aquaculture tank 11 in which fish are grown and the cultivation tank 12a in which plants are grown, and the circulating concentrated water is purified in a water treatment device 13; a second growth step S20 in which plants are grown using fresh water; and a dilution step S30 (mixing step) in which the first waste liquid produced in the water treatment device 13 and the second waste liquid produced by the growth of plants in the second growth step S20 are mixed.

[0092] By configuring in this way, it is possible to effectively utilize the waste liquid.

[0093] The water treatment device 13 according to this embodiment is one embodiment of the purification section according to the present invention. The aquaponics system 10 according to this embodiment is one embodiment of a first growing section according to the present invention. The hydroponic cultivation device 30 according to this embodiment is one embodiment of the second growing section according to the present invention. The adjusting tank 50 according to this embodiment is one embodiment of the mixing section according to the present invention. The nutrient solution cultivation device 60 according to this embodiment is an embodiment of a third growing section according to the present invention. The foam separator 13b according to this embodiment is one embodiment of the foam separation section according to the present invention. The first waste liquid tank 20 according to this embodiment is one embodiment of a first reservoir according to the present invention. The second waste liquid tank 40 according to this embodiment is one embodiment of a second reservoir according to the present invention. The sterilization device 70 according to this embodiment is one embodiment of the sterilization section according to the present invention. The dilution step S30 according to this embodiment is an embodiment of the mixing step according to the present invention.

[0094] Next, a waste liquid utilization system 101 according to a second embodiment shown in FIGS. 8 and 9 will be described.

[0095] The waste liquid utilization system 101 of this embodiment differs from the waste liquid utilization system 1 of the first embodiment (see FIG. 2) in that the water used to wash the water treatment device 13 can be mixed in the adjustment tank 50. This difference will be described below.

[0096] The filtration tank 13a and the foam separator 13b are configured to allow the introduction of cleaning water (not shown). As shown in Fig. 9, the waste liquid utilization system 101 is provided with pipes K11 and K12 for guiding cleaning water used to clean the filtration tank 13a and the like. The cleaning water is water used to clean the water treatment device 13. In this embodiment, the cleaning water is water used to clean the filtration tank 13a and the foam separator 13b. The cleaning water is water that is under a higher pressure than the high-concentrate water that is circulated between the aquaculture tank 11 and the cultivation device 12, for example.

[0097] The pipe K11 connects the filtration tank 13a and the first waste liquid tank 20. The pipe K12 connects the foam separator 13b and the pipe K11. A pump 80 is provided at the connection between the pipes K11 and K12. When the pump 80 is driven, the cleaning water used to clean the filtration tank 13a is introduced into the first waste liquid tank 20 via the pipe K11. The cleaning water used to clean the foam separator 13b is introduced into the first waste liquid tank 20 via the pipes K11 and K12.

[0098] The cleaning water introduced into the first waste liquid tank 20 has a relatively high salt concentration because it is water used to clean the filtration tank 13a and other equipment used in a high-salt environment. This cleaning water is introduced into the adjustment tank 50 shown in Figure 8 and mixed with the second waste liquid. This reduces the salt concentration of the cleaning water, allowing it to be used as liquid fertilizer (effectively utilizing the cleaning water).

[0099] In this embodiment, both the cleaning water used to clean the filtration tank 13a and the cleaning water used to clean the foam separator 13b are stored in the same tank (first waste liquid tank 20), but this is not limited to this and they may be stored in separate tanks.

[0100] As described above, the waste liquid utilization system 101 according to this embodiment further includes a pump 80 (cleaning water supply unit) capable of pumping out cleaning water for cleaning the water treatment device 13, and the cleaning water used to clean the water treatment device 13 is introduced into the adjustment tank 50.

[0101] By configuring in this way, it is possible to effectively utilize the cleaning water.

[0102] The pump 80 according to this embodiment is one embodiment of the cleaning water supply section according to the present invention.

[0103] 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.

[0104] For example, in the adjustment tank 50, the first waste liquid and the second waste liquid are mixed in a 1:1 ratio, but this ratio is just an example and can be changed as appropriate depending on the type of plants grown in the hydroponic cultivation device 60, etc.

[0105] Furthermore, the first waste liquid and the second waste liquid mixed in the adjustment tank 50 are used as liquid fertilizer, but the use of the waste liquid is not limited to liquid fertilizer and can be changed as appropriate.

[0106] Furthermore, the water treatment device 13 is described as including the filtration tank 13a and the foam separator 13b, but this is merely an example, and the configuration of the water treatment device 13 may be appropriately changed as needed. For example, in cases where the highly concentrated water can be sufficiently purified by the filtration tank 13a (physical filtration, biological filtration), the foam separator 13b may be omitted.

[0107] Furthermore, the first waste liquid and the second waste liquid are stored in the first waste liquid tank 20 and the second waste liquid tank 40, but this is not limitative. The first waste liquid, etc. may be introduced into the adjustment tank 50 without being stored in a tank.

[0108] Although the first waste liquid is introduced from the first waste liquid tank 20 to the adjustment tank 50 by overflow, the method of introducing the first waste liquid is not limited to this embodiment. For example, the first waste liquid may be introduced from the first waste liquid tank 20 to the adjustment tank 50 using a pump.

[0109] Furthermore, although the water treatment device 13 is assumed to be cleaned with cleaning water (high-pressure water), the method for cleaning the water treatment device 13 is not particularly limited. For example, the water treatment device 13 can also be cleaned by a backwash function in which water flows in the opposite direction to that used for purifying highly concentrated water. When the water treatment device 13 is cleaned by the backwash function, the aquaponics system 10 of the second embodiment may be configured to store waste liquid (backwash waste liquid) generated by the backwash function in the first waste liquid tank 20. With this configuration, the backwash waste liquid can be effectively utilized without being discarded, making it easier to introduce a water treatment device 13 with a backwash function. [Explanation of symbols]

[0110] 1 Waste liquid utilization system 10. Aquaponics Systems 11 Aquaculture tank 12a Cultivation tank 30 Hydroponic cultivation equipment 50 Adjustment tank

Claims

1. a first growth section that circulates concentrated water having a higher salt concentration than fresh water between an aquaculture tank for growing fish and a cultivation tank for growing plants, and purifies the circulating concentrated water in a purification section; a second growing section for growing plants using freshwater; a mixing section that mixes the first waste liquid generated in the purification section and the second waste liquid generated by the growth of plants in the second growth section; Equipped with Waste liquid utilization system.

2. The system further includes a third growing section for growing plants using fertilizer prepared from the waste liquid mixed in the mixing section. The waste liquid utilization system according to claim 1.

3. The ratio at which the first waste liquid and the second waste liquid are mixed in the mixing section is The temperature is set according to the plants grown in the third growing section. The waste liquid utilization system according to claim 2.

4. The purification unit includes: A foam separation unit is provided which removes foam generated in the concentrated water, thereby removing adsorbed substances adsorbed to the foam together with the foam, The first waste liquid includes: The foam removed in the foam separation section is included. The waste liquid utilization system according to any one of claims 1 to 3.

5. Further comprising a first reservoir for storing the first waste liquid. The waste liquid utilization system according to claim 4.

6. Further comprising a second reservoir for storing the second waste liquid, Further comprising a sterilization unit that sterilizes at least one of the first waste liquid stored in the first storage unit and the second waste liquid stored in the second storage unit. The waste liquid utilization system according to claim 5.

7. The system further includes an adjusting unit that adjusts at least one of the amount of the first waste liquid supplied from the purification unit to the mixing unit and the amount of the second waste liquid supplied from the second growth unit to the mixing unit. The waste liquid utilization system according to any one of claims 1 to 3.

8. Further, a cleaning water supply unit capable of sending out cleaning water for cleaning the purification unit is provided. The mixing section includes: The cleaning water used to clean the purification unit is introduced. The waste liquid utilization system according to any one of claims 1 to 3.

9. a first growth process in which concentrated water having a higher salt concentration than freshwater is circulated between an aquaculture tank in which fish are grown and a cultivation tank in which plants are grown, and the circulating concentrated water is purified in a purification unit; a second growing step of growing plants using freshwater; a mixing step of mixing the first waste liquid generated in the purification section and the second waste liquid generated by the growth of plants in the second growth step; Equipped with How to use waste liquid.

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