Wastewater mixing system

Abstract

We provide a waste liquid mixing system that enables the effective utilization of waste liquid. [Solution] The system comprises: an adjustment tank 33 for mixing a first wastewater generated in an aquaponics system 10 that raises fish and plants using high-concentration water with a higher salinity than freshwater, and a second wastewater generated in a hydroponic cultivation device 20 that grows plants using freshwater; a salinity sensor 38 capable of detecting the salinity of the mixture of the first and second wastewaters; a valve 31a and a pump 32a capable of supplying the first and second wastewaters to the adjustment tank 33; and a control unit 39 that controls the valve 31a and the pump 32a to adjust the amount of the first wastewater supplied to the adjustment tank 33, or the amount of the second wastewater supplied to the adjustment tank 33, according to the detection result of the salinity sensor 38, thereby performing wastewater mixing control.

Description

Technical Field

[0001] The present invention relates to a technology of a waste liquid mixing system that mixes waste liquids generated in the growth of fish and the growth of plants.

Background Art

[0002] Conventionally, technologies for utilizing waste liquids generated in the growth of fish and the growth of plants are well-known. For example, it is as described in Patent Document 1.

[0003] The aquaponics system described in Patent Document 1 includes an aquaculture tank for growing fish, a hydroponics section for growing plants, a physical filtration device, an anaerobic tank, and the like. The aquaponics system is configured such that water circulates in the order of the aquaculture tank, the hydroponics section, and the physical filtration device. The physical filtration device can rub solids contained in water with filter media or the like. The solids are washed away by water. Water (waste liquid) from which the solids have been washed away is introduced into the anaerobic tank. In the anaerobic tank, organic substances contained in the introduced water are decomposed by anaerobic microorganisms, generating sludge. The sludge is supplied to plants. Thus, the waste liquid generated in the aquaponics system is utilized as fertilizer.

[0004] Since freshwater fish (sharks) are grown in the aquaculture tank of Patent Document 1, it is considered that freshwater circulates. If water having a higher salt concentration than freshwater (such as artificial seawater) is circulated in the aquaponics system of Patent Document 1, this water having a high salt concentration is introduced into the anaerobic tank. Therefore, more salty sludge is generated than when circulating freshwater, and it may be difficult to use it as fertilizer. Thus, the aquaponics system of Patent Document 1 may not be able to effectively utilize waste liquid depending on the type of water to be circulated.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] This invention was made in view of the above circumstances, and the problem it aims to solve is to provide a waste liquid mixing system that can effectively utilize waste liquid. [Means for solving the problem]

[0007] The problems that this invention aims to solve are as described above, and the means for solving these problems will now be explained.

[0008] In other words, claim 1 provides a mixing unit that mixes a first wastewater generated in an aquaponics system that raises fish and plants using high-concentration water with a higher salinity than freshwater, and a second wastewater generated in a freshwater growing unit that grows plants using freshwater; a concentration detection unit capable of detecting the salinity of the mixture of the first and second wastewaters; a first supply unit capable of supplying the first and second wastewaters to the mixing unit; and a control unit that controls the first supply unit to perform a first control that adjusts at least one of the amount of the first wastewater supplied to the mixing unit or the amount of the second wastewater supplied to the mixing unit according to the detection result of the concentration detection unit.

[0009] In claim 2, the mixture is supplied to plants grown in a location different from the aquaponics system and the freshwater growing section, and the control unit adjusts the supply amount in the first control so that the detection result of the concentration detection unit does not exceed a threshold set according to the plants to which the mixture is supplied.

[0010] In claim 3, the control unit, in the first control, supplies either the first waste liquid or the second waste liquid to the mixing unit, and then supplies the other of the first waste liquid or the second waste liquid to the mixing unit.

[0011] In claim 4, the control unit, in the first control, supplies the first waste liquid to the mixing unit and then supplies the second waste liquid to the mixing unit until the detection result of the concentration detection unit falls below the threshold.

[0012] Claim 5 further comprises a second supply unit capable of supplying the high-concentration water circulating in the aquaponics system to the mixing unit, and the control unit performs a second control in which it compensates for the shortage of the first waste liquid by supplying the high-concentration water to the mixing unit when the first waste liquid is insufficient.

[0013] Claim 6 further comprises a storage unit capable of storing the first waste liquid and connected to the mixing unit so as to be able to introduce the first waste liquid into the mixing unit, and an introduction detection unit for detecting whether or not the first waste liquid can be introduced from the storage unit to the mixing unit, wherein the control unit controls the second supply unit to supply the high-concentration water to the mixing unit when the introduction detection unit detects that the first waste liquid cannot be introduced.

[0014] In claim 7, the introduction detection unit detects whether or not the first waste liquid can be introduced based on the water level in the storage unit.

[0015] Claim 8 further comprises a third supply unit capable of supplying fresh water to the mixing unit, and the control unit performs a third control that compensates for the shortage of the second waste liquid with fresh water by controlling the third supply unit to supply fresh water to the mixing unit when the second waste liquid is insufficient. [Effects of the Invention]

[0016] The present invention provides the following effects:

[0017] Claim 1 allows for the effective utilization of waste liquid.

[0018] In claim 2, the salt concentration can be appropriately adjusted according to the plant.

[0019] In claim 3, it is possible to make it easier to adjust the salt concentration.

[0020] In claim 4, it is possible to make it even easier to adjust the salt concentration.

[0021] In claim 5, the shortage of the first waste liquid can be supplemented with high-concentration water.

[0022] In claim 6, the second supply unit can be appropriately controlled according to the detection result of the introduction detection unit.

[0023] In claim 7, it is possible to make it easier to determine whether the first waste liquid is insufficient.

[0024] In claim 8, the shortage of the second waste liquid can be supplemented with fresh water.

Brief Description of the Drawings

[0025] [Figure 1] An explanatory diagram showing a growth system including a waste liquid mixing system according to an embodiment of the present invention. [Figure 2] An explanatory diagram showing the growth system in detail. [Figure 3] An elevation view showing the growth system. [Figure 4] An elevation view showing an aquaponics system. [Figure 5] An elevation view showing a hydroponic cultivation device and a waste liquid mixing system. [Figure 6] A flowchart showing alternative water supply control. [Figure 7] (a) An elevation view showing a state where high-concentration water is introduced into the first waste liquid tank. (b) An elevation view showing a state where the first waste liquid is introduced into the first waste liquid tank. [Figure 8] A flowchart showing waste liquid mixing control. [Figure 9]An elevation view showing the state in which the first waste liquid is introduced into the adjustment tank. [Figure 10] (a) Elevation view showing the introduction of the second wastewater into the adjustment tank. (b) Elevation view showing the introduction of tap water into the adjustment tank. [Modes for carrying out the invention]

[0026] The following describes a growth system 1 equipped with a wastewater mixing system 30 according to one embodiment of the present invention. The growth system 1 is a system for raising fish and plants using an aquaponics system 10, etc. First, the outline of the growth system 1 will be described with reference to Figure 1.

[0027] The aquaponics system 10 combines hydroponics and fish farming to allow plants to absorb nutrients (such as nitrogen) produced during fish farming, thereby purifying the water while the plants grow. The aquaponics system 10 is configured to circulate water with a higher salinity than freshwater (natural seawater, artificial seawater, etc., hereinafter referred to as "high-concentration water") between the fish farming tank 11 and the plant cultivation device 12. In the fish farming tank 11, marine fish are farmed using high-concentration water. In the cultivation device 12, hydroponics is carried out using 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 freshwater but lower than seawater.

[0028] The highly concentrated water circulating between the aquaculture tank 11 and the cultivation device 12 is purified by the water treatment device 13. The wastewater and sludge generated when purifying the highly concentrated water are discharged to the outside of the aquaponics system 10 (to the first wastewater tank 31, described later). Hereinafter, the wastewater and sludge discharged from the aquaponics system 10 will be referred to as "first wastewater".

[0029] The first wastewater contains many plant nutrients (potassium, calcium, magnesium, etc.), so if the first wastewater is used as fertilizer, highly concentrated water can be reused. However, because the first wastewater has a high salt concentration, if it is used as fertilizer, the salt concentration of the first wastewater must be reduced to a level that can suppress the occurrence of salt damage.

[0030] Therefore, in the growth system 1, the wastewater mixing system 30 dilutes the first wastewater with wastewater that has a lower salt concentration than the first wastewater. More specifically, the first wastewater is diluted with wastewater generated in the hydroponic cultivation device 20, which uses freshwater for hydroponic cultivation (hereinafter referred to as "second wastewater"). By providing the plants with the diluted first wastewater as fertilizer (liquid fertilizer), the growth system 1 is configured to utilize both wastewaters together. In this embodiment, the fertilizer is provided to plants grown in the nutrient solution cultivation device 40.

[0031] The configuration of the growth system 1 is described below. As shown in Figure 1, the growth system 1 comprises an aquaponics system 10, a hydroponic cultivation device 20, a wastewater mixing system 30, and a nutrient solution cultivation device 40.

[0032] The aquaponics system 10 is a system that combines hydroponics and fish farming. As shown in Figures 2 and 3, the aquaponics system 10 comprises a farming tank 11, a cultivation device 12, and a water treatment device 13.

[0033] The aquaculture tank 11 is for raising fish (seawater fish) in high-concentration water. High-concentration water is stored in the aquaculture tank 11. As shown in Figure 4, the aquaculture tank 11 is connected to the filtration tank 13a of the water treatment device 13, which will be described later, via two pipes K1 and K2. High-concentration water is introduced into the aquaculture tank 11 from the filtration tank 13a via pipe K1. High-concentration water is also introduced into the filtration tank 13a from the aquaculture tank 11 via pipe K2. In this embodiment, when the water level in the aquaculture tank 11 reaches a predetermined height, the high-concentration water overflows via pipe K2 and is introduced into the filtration tank 13a.

[0034] The cultivation apparatus 12 shown in Figures 2 and 3 is for hydroponic cultivation using high-concentration water. The cultivation apparatus 12 includes a cultivation tank 12a (see Figure 3) in which high-concentration water is stored. Plants are planted in the cultivation tank 12a so that their roots are submerged in the high-concentration water. In this way, plants are grown in the cultivation tank 12a by hydroponics. The cultivation apparatus 12 is connected to a filtration tank 13a via two pipes (not shown), similar to the aquaculture tank 11. The cultivation apparatus 12 is also configured to allow high-concentration water to flow between it and the filtration tank 13a as needed. For example, the cultivation apparatus 12 is configured to allow high-concentration water to flow between it and the filtration tank 13a by a pump or the like.

[0035] The water treatment device 13 is for purifying high-concentration water. The water treatment device 13 is positioned between the aquaculture tank 11 and the cultivation device 12 (see Figure 2). The water treatment device 13 comprises a filtration tank 13a and a foam separator 13b.

[0036] The filtration tank 13a is for filtering high-concentration water and adjusting its composition. In this embodiment, the filtration includes both physical and biological filtration. Through physical filtration, the filtration tank 13a can filter out impurities contained in the high-concentration water. Through biological filtration, the filtration tank 13a can nitrify ammonia contained in the high-concentration water, converting it into nitrates, etc. Since these nitrates, etc., are nutrients for plants, they are absorbed by the plants in the cultivation device 12. In this way, the aquaponics system 10 can suppress the increase in the concentration of nitrates, etc., which are weakly toxic to fish, and grow fish and plants simultaneously.

[0037] The foam separator 13b is a device that purifies high-concentration water by utilizing the property that pollutants are adsorbed onto foam. The foam separator 13b is equipped with a tank (not shown) capable of storing high-concentration water. As shown in Figure 4, the foam separator 13b is connected to the filtration tank 13a via two pipes K3 and K4. The pipes K3 and K4 are connected to each other via a switching valve 34. The switching valve 34 will be described later. A pump 13c is provided in pipe K3. When the pump 13c is driven, high-concentration water from the filtration tank 13a can be introduced into the foam separator 13b (tank).

[0038] The foam separator 13b can generate foam in the high-concentration water from the filtration tank 13a. Pollutants are adsorbed onto this foam. By removing the foam, the foam separator 13b can purify the high-concentration water by removing the adsorbed substances along with the foam. The foam separator 13b can also return the purified high-concentration water to the filtration tank 13a via piping K5. Note that the adsorbed substances removed along with the foam by the foam separator 13b may include substances other than pollutants. For example, the adsorbed substances may include trace metals (iron, copper, zinc, manganese, molybdenum, boron, chlorine, nickel), etc.

[0039] In the aquaponics system 10, high-concentration water is configured to circulate between the aquaculture tank 11 and the cultivation device 12 via piping K1, K2, etc. A pump (for example, pump 14 shown in Figure 4) is provided in the circulation path of the high-concentration water, and when the pump is driven, the high-concentration water flows from the cultivation device 12 through the water treatment device 13 to the aquaculture tank 11, as shown in Figure 2. The high-concentration water also flows from the aquaculture tank 11 through the water treatment device 13 to the cultivation device 12. Thus, in this embodiment, the high-concentration water is configured to pass 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, since high-concentration water flows from the aquaculture tank 11 to the filtration tank 13a by overflow, the number of pumps required to circulate the high-concentration water can be reduced.

[0040] Furthermore, the circulation path of the high-concentration water is not limited to this embodiment, as long as it 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 high-concentration water 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.

[0041] Here, the high-concentration water is purified by passing through the water treatment device 13, which then passes through the filtration tank 13a and the foam separator 13b. At this time, foam is removed in the foam separator 13b. The waste liquid containing the foam (foam separator) and the sludge generated by the purification of the high-concentration 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 31 via the piping K6 shown in Figure 4. More specifically, the waste liquid, etc., overflows from the foam separator 13b via the piping K6 and is discharged to the first waste liquid tank 31. In this embodiment, the waste liquid, etc., is the first waste liquid discharged from the aquaponics system 10.

[0042] The hydroponic cultivation system 20 shown in Figures 2 and 3 is used to grow plants using freshwater hydroponics. The hydroponic cultivation system 20 comprises a cultivation tank 21 and a nutrient solution tank 22.

[0043] Cultivation tank 21 is for growing plants. The same types of plants as those in cultivation tank 12a are grown in cultivation tank 21. The plants in cultivation tank 21 are less developed than those in cultivation tank 12a. More specifically, seedlings are grown in cultivation tank 21, while plants that have finished their seedling stage are grown in cultivation tank 12a. Freshwater nutrient solution is stored in cultivation tank 21. Freshwater nutrient solution is a liquid made by dissolving fertilizer in freshwater. Plants are planted in cultivation tank 21 so that their roots are submerged in the freshwater nutrient solution.

[0044] The nutrient solution tank 22 is for adjusting the nutrient content of the freshwater nutrient solution. Freshwater nutrient solution is stored in the nutrient solution tank 22. As shown in Figure 5, the nutrient solution tank 22 is connected to the cultivation tank 21 via two pipes K7 and K8. The nutrient solution tank 22 is also equipped with a pump 23. When the pump 23 is driven, the freshwater nutrient solution from the nutrient solution tank 22 is introduced into the cultivation tank 21 via pipe K7. The freshwater nutrient solution from the cultivation tank 21 is also introduced into the nutrient solution tank 22 via pipe K8. In this way, the hydroponic cultivation system 20 can grow plants by circulating freshwater nutrient solution between the nutrient solution tank 22 and the cultivation tank 21.

[0045] In this embodiment, plants are grown in the hydroponic cultivation device 20 until the seedling stage is over. These plants are then transplanted to the aquaponics system 10 (cultivation tank 12a). This helps to suppress the occurrence of salt damage.

[0046] Specifically, plants in the seedling stage have relatively low salt tolerance because their growth is not yet advanced. On the other hand, plants that have finished the seedling stage have relatively high salt tolerance because their growth has progressed. Therefore, in this embodiment, plants that have been grown in cultivation tank 21 (freshwater) until the end of the seedling stage are transplanted to the aquaponics system 10 and grown in high-concentration water. This allows plants to be grown in water (salinity) appropriate to their salt tolerance, thereby suppressing the occurrence of salt damage in the aquaponics system 10.

[0047] Furthermore, since the water quality deteriorates if freshwater nutrient solution is used continuously, the hydroponic cultivation system 20 is configured to allow for the replacement of the freshwater nutrient solution. In this embodiment, the hydroponic cultivation system 20 is configured to allow for the replacement of the freshwater nutrient solution by means of piping K9, the first valve 24, and the second valve 25.

[0048] Specifically, piping K9 guides the freshwater nutrient solution from the cultivation tank 21 to the second wastewater tank 32, which will be described later. Piping K9 is connected to the cultivation tank 21 via piping K8, which guides the freshwater nutrient solution from the cultivation tank 21 to the nutrient solution tank 22. The first valve 24 switches whether or not the freshwater nutrient solution can flow from the cultivation tank 21 to the second wastewater tank 32. The first valve 24 is installed in piping K9. The second valve 25 switches whether or not the freshwater nutrient solution can flow from the cultivation tank 21 to the nutrient solution tank 22. The second valve 25 is installed in piping K8.

[0049] When the first valve 24 is closed and the second valve 25 is opened, the hydroponic system 20 is switched to a first state in which freshwater nutrient solution can be circulated between the cultivation tank 21 and the nutrient solution tank 22. In this state, the pump 23 is driven to circulate the freshwater nutrient solution, and the plants in the cultivation tank 21 grow.

[0050] Furthermore, when the first valve 24 is opened and the second valve 25 is closed, the hydroponic cultivation system 20 is switched to a second state in which freshwater nutrient solution can be discharged to the second wastewater tank 32. The hydroponic cultivation system 20 is switched to the second state, for example, when transplanting plants from the cultivation tank 21 to the aquaponics system 10. In this state, the pump 23 is driven, and the freshwater nutrient solution is discharged from the cultivation tank 21 to the second wastewater tank 32. This freshwater nutrient solution is the second wastewater generated during plant growth in the hydroponic cultivation system 20. After the freshwater nutrient solution is discharged, the cultivation tank 21 and the nutrient solution tank 22 are replenished with freshwater nutrient solution. In this way, the freshwater nutrient solution is replaced.

[0051] The waste liquid mixing system 30 shown in Figures 2 and 3 is a system for mixing a first waste liquid and a second waste liquid. The waste liquid mixing system 30 comprises a first waste liquid tank 31, a second waste liquid tank 32, an adjustment tank 33, a switching valve 34, a first water level sensor 35, a second water level sensor 36, a third water level sensor 37, a salinity sensor 38, and a control unit 39.

[0052] The first wastewater tank 31 stores the first wastewater from the aquaponics system 10. As shown in Figure 4, the first wastewater is introduced into the first wastewater tank 31 via piping K6. As shown in Figure 5, the first wastewater tank 31 is connected to a regulating tank 33, which will be described later, via piping K10. In this embodiment, the first wastewater tank 31 can be used to circulate the first wastewater to the regulating tank 33 by overflow. For example, by positioning the first wastewater tank 31 higher than the regulating tank 33, or by forming it in a shape that is longer vertically than the regulating tank 33, the first wastewater can be allowed to overflow via piping K10 and circulate to the regulating tank 33. In this way, the first wastewater in this embodiment circulates from the foam separator 13b to the first wastewater tank 31 and the regulating tank 33 by overflow. This configuration reduces the number of pumps required to circulate the first wastewater.

[0053] Here, the first waste liquid stored in the first waste liquid tank 31 may contain solid matter (for example, solid pollutants). By storing the first waste liquid in the first waste liquid tank 31, the solid matter can be separated and removed. For example, if the solid matter settles, it can be removed by sedimentation.

[0054] As shown in Figure 5, a valve 31a is provided in the piping K10. The valve 31a is configured as, for example, a solenoid valve. By operating the valve 31a remotely, it is possible to switch between a state in which the piping K10 is opened and the first waste liquid is introduced into the adjustment tank 33, and a state in which the piping K10 is closed and the first waste liquid is not introduced into the adjustment tank 33.

[0055] The second wastewater tank 32 stores the second wastewater from the hydroponic cultivation system 20. The second wastewater is introduced into the second wastewater tank 32 via piping K9. The second wastewater tank 32 is connected to the adjustment tank 33 via piping K12. In this embodiment, a pump 32a is provided in the second wastewater tank 32. By remotely operating the pump 32a, it is possible to switch between a state in which the pump 32a is driven and the second wastewater is introduced into the adjustment tank 33, and a state in which the pump 32a is stopped and the second wastewater is not introduced into the adjustment tank 33.

[0056] Furthermore, the first wastewater tank 31 and the second wastewater tank 32 may be equipped with sterilization devices. With this configuration, the first and second wastewater stored in the first wastewater tank 31, etc., can be sterilized, and the deterioration of water quality can be suppressed.

[0057] The adjustment tank 33 shown in Figures 2 and 3 mixes the first wastewater and the second wastewater. In the adjustment tank 33, the first wastewater and the second wastewater are basically mixed in a predetermined ratio. For example, the first wastewater and the second wastewater are mixed in a ratio corresponding to the plants grown in the hydroponic cultivation device 40 described later. In this case, for example, the first wastewater and the second wastewater are mixed in a ratio that results in a component concentration suitable for the growth of the plants. In this embodiment, the first wastewater and the second wastewater are mixed in a 1:1 ratio. Hereinafter, the predetermined mixing ratio of the first wastewater and the second wastewater will be referred to as the "standard ratio".

[0058] The adjustment tank 33 mixes the first wastewater, which is generated from high-concentration water, with the second wastewater, which is generated from fresh water. This dilutes the first wastewater, which has a high salt concentration, with the second wastewater, thereby lowering the salt concentration of the first wastewater. In the adjustment tank 33, this first wastewater, with its reduced salt concentration, is stored as liquid fertilizer.

[0059] The adjustment tank 33 in this embodiment is configured to allow the introduction of fresh water as needed. In Figures 2 and 3, a tap water supply device 33b capable of supplying tap water to a connected destination is connected to the adjustment tank 33, and tap water is supplied to the adjustment tank 33 as appropriate by the tap water supply device 33b. In addition, fertilizer may be introduced into the adjustment tank 33 as needed. For example, if the first wastewater is deficient in components necessary for plant growth (such as potassium), fertilizer may be introduced into the adjustment tank 33 to supplement these components.

[0060] As shown in Figure 3, the adjustment tank 33 is equipped with a pump 33a, and when the pump 33a is driven, the liquid fertilizer in the adjustment tank 33 is introduced into the hydroponic cultivation device 40.

[0061] The hydroponic cultivation system 40 grows plants using liquid fertilizer (a mixture of first and second wastewater) stored in the adjustment tank 33. The hydroponic cultivation system 40 is used to grow relatively salt-tolerant plants. For example, plants that can grow in water with a higher salinity than freshwater but lower salinity than seawater are grown. In this embodiment, tomatoes are grown. In the hydroponic cultivation system 40, tomatoes are planted in a growing medium such as rockwool. The liquid fertilizer introduced from the adjustment tank 33 into the hydroponic cultivation system 40 is supplied to the tomatoes. For example, the liquid fertilizer is supplied to the tomatoes by drip irrigation.

[0062] By supplying liquid fertilizer to plants in this way, the nutrients abundant in the highly concentrated water (first wastewater) can be utilized for plant growth. Furthermore, since the liquid fertilizer is a mixture of the first and second wastewater, both wastewaters can be used together for plant growth, thus promoting effective utilization of the wastewater. In particular, the first wastewater (wastewater that is difficult to use) generated in the aquaponics system 10 can be effectively utilized without being discarded.

[0063] As mentioned above, the first wastewater contains foam removed by the foam separator 13b. Trace metals (such as iron) contained in high-concentration water may be adsorbed onto this foam. These trace metals are nutrients for plants. Therefore, when trace metals are adsorbed onto the foam by the foam separator 13b, liquid fertilizer containing trace metals can be supplied to the plants in the hydroponic cultivation device 40, thereby supplying the plants with trace metals and promoting their growth.

[0064] Here, the composition and properties of the wastewater (first wastewater and second wastewater) are expected to fluctuate due to various factors. For example, the salinity of the high-concentration water fluctuates depending on the growth status of the fish in the aquaculture tank 11, and the salinity and properties of the first wastewater fluctuate in accordance with this fluctuation. In addition, various wastewaters with different salinity concentrations (foam separation liquid, wastewater containing sludge, etc.) are collected in the adjustment tank 33. Since the amount (ratio) of these wastewaters is not expected to be constant, the salinity of the wastewater fluctuates according to the amount of wastewater.

[0065] Therefore, if the first and second waste liquids are mixed in a predetermined fixed ratio (standard ratio), the salt concentration of the liquid fertilizer will fluctuate in accordance with the aforementioned fluctuations in salt concentration. In this case, it becomes difficult to appropriately adjust (control) the salt concentration of the liquid fertilizer.

[0066] Furthermore, since the timing and quantity of generation of the first and second wastewater differ from each other, there is a concern that either the first or second wastewater may become insufficient. If either the first or second wastewater becomes insufficient, it may become impossible to produce liquid fertilizer in the adjustment tank 33, or the amount of liquid fertilizer produced may decrease, making it difficult to stably supply liquid fertilizer to the hydroponic cultivation system 40.

[0067] The wastewater mixing system 30 of this embodiment is configured to adjust the mixing ratio of wastewater based on a standard ratio by adjusting the amount of wastewater introduced based on the detection result of the salinity sensor 38, thereby responding to fluctuations in the salinity of the wastewater. Furthermore, the wastewater mixing system 30 is configured to compensate for any shortage of the first or second wastewater with other water (alternative water) by controlling the switching valve 34, etc., according to the detection result of the first water level sensor 35, etc. The following describes the equipment related to these configurations. Specifically, the switching valve 34, the first water level sensor 35, the second water level sensor 36, the third water level sensor 37, the salinity sensor 38, and the control unit 39 will be described.

[0068] The switching valve 34 shown in Figure 4 switches whether or not the highly concentrated water circulating in the aquaponics system 10 can be introduced into the first wastewater tank 31. The switching valve 34 is composed of, for example, a solenoid valve. The aforementioned pipes K3 and K4 and pipe K11 are connected to the switching valve 34. Pipe K11 guides the highly concentrated water to the first wastewater tank 31.

[0069] The switching valve 34 can be remotely operated to switch between a first switching state, in which high-concentration water can flow from piping K3 to piping K4, and a second switching state, in which high-concentration water can flow from piping K3 to piping K11. When the switching valve 34 is switched to the second switching state, the high-concentration water is introduced to the first wastewater tank 31 via piping K3 and K11. When the switching valve 34 is switched to the first switching state, the high-concentration water is introduced to the foam separator 13b via piping K3 and K4. In this case, first wastewater is generated in the foam separator 13b, and this first wastewater is introduced to the first wastewater tank 31.

[0070] The first water level sensor 35 detects the water level in the first waste liquid tank 31. In this embodiment, the first water level sensor 35 is configured to detect whether the water level is below a preset first lower limit water level and whether it has reached (or is above) a first upper limit water level.

[0071] The first lower limit water level is the minimum water level at which the substances (first waste liquid and high-concentration water) stored in the first waste liquid tank 31 can be introduced into the adjustment tank 33. In this embodiment, since the first waste liquid, etc., is introduced into the adjustment tank 33 by overflow, the first lower limit water level is the minimum water level at which the first waste liquid, etc., overflows. Note that this is just one example, and the first lower limit water level can be appropriately set depending on the method of introducing the first waste liquid, etc., from the first waste liquid tank 31 into the adjustment tank 33. For example, when introducing the first waste liquid, etc., into the adjustment tank 33 by driving a pump, the first lower limit water level may be the limit water level at which the pump can operate (without running dry). The first water level sensor 35 can detect whether or not the first waste liquid can be introduced from the first waste liquid tank 31 into the adjustment tank 33 by detecting whether or not the water level in the first waste liquid tank 31 is below the first lower limit water level.

[0072] The first upper limit water level is the upper limit of the water level in the first waste liquid tank 31 when high-concentration water is introduced into the first waste liquid tank 31. The first upper limit water level is set appropriately within a range that is higher than the first lower limit water level and less than or equal to the maximum water level that can be stored in the first waste liquid tank 31.

[0073] The second water level sensor 36 shown in Figure 5 detects the water level in the second waste liquid tank 32. The second water level sensor 36 in this embodiment is configured to detect whether or not the water level is below a preset second lower limit.

[0074] The second lower limit water level is the minimum water level at which the second waste liquid stored in the second waste liquid tank 32 can be introduced into the adjustment tank 33. In this embodiment, since the second waste liquid is introduced into the adjustment tank 33 by the pump 32a, the second lower limit water level is the limit water level at which the pump 32a can operate (without running dry). This is just one example, and the second lower limit water level can be set appropriately depending on the method of introducing the second waste liquid from the second waste liquid tank 32 into the adjustment tank 33. For example, if the second waste liquid stored in the second waste liquid tank 32 is introduced into the adjustment tank 33 by overflowing, the lower limit water level may be the minimum water level at which the second waste liquid overflows. The second water level sensor 36 can detect whether the second waste liquid can be introduced from the second waste liquid tank 32 into the adjustment tank 33 by detecting whether the water level in the second waste liquid tank 32 is below the second lower limit water level.

[0075] The third water level sensor 37 detects the water level in the adjustment tank 33. The third water level sensor 37 is configured to detect whether the water level is below a preset third lower limit water level and whether it has reached a preset third upper limit water level.

[0076] The third lower limit water level is the minimum water level at which the liquid fertilizer stored in the adjustment tank 33 can be introduced into the hydroponic cultivation device 40. In this embodiment, since the liquid fertilizer is introduced into the hydroponic cultivation device 40 by the pump 33a shown in Figure 3, the third lower limit water level is the limit water level at which the pump 33a can operate (without running dry). Note that this is just one example, and the level can be set appropriately depending on the method of supplying the liquid fertilizer from the adjustment tank 33 to the hydroponic cultivation device 40.

[0077] The third upper limit water level is the upper limit of the water level in the adjustment tank 33 when the first waste liquid (and high-concentration water) is introduced into the adjustment tank 33. As will be described later, the waste liquids are introduced into the adjustment tank 33 in the order of the first waste liquid and then the second waste liquid. In this embodiment, the mixing ratio of the first waste liquid, etc. is adjusted based on a standard ratio (1:1). For this reason, the third upper limit water level in this embodiment is set to a water level that is less than or equal to half of the maximum water level that can be stored in the adjustment tank 33. This makes it possible to prevent the waste liquid from overflowing from the adjustment tank 33 when the first waste liquid, etc. is mixed based on the standard ratio.

[0078] The third upper limit water level mentioned above is just an example, and can be set appropriately according to the size of the first wastewater tank 31 and the adjustment tank 33, the standard ratio, etc.

[0079] The salinity sensor 38 shown in Figure 5 detects the salinity of the substance (liquid fertilizer, etc.) stored in the adjustment tank 33. The salinity sensor 38 is installed in the adjustment tank 33. The type of salinity sensor 38 is not particularly limited, but in this embodiment, the salinity sensor 38 is composed of an EC (Electrical Conductivity) sensor that detects the salinity based on electrical conductivity.

[0080] The control unit 39 shown in Figures 4 and 5 performs various processes on the waste liquid mixing system 30. The control unit 39 comprises a first control unit 39a and a second control unit 39b.

[0081] The first control unit 39a shown in Figure 4 is responsible for compensating for any shortage of the first waste liquid with alternative water (high-concentration water). The first control unit 39a includes an arithmetic unit capable of performing calculations, a memory device storing programs and the like, and a communication device capable of communicating with external equipment. The first control unit 39a is connected to the switching valve 34 and the first water level sensor 35.

[0082] The first control unit 39a can control the flow path of high-concentration water by switching the state of the switching valve 34 by outputting a signal to the switching valve 34. For example, by switching the switching valve 34 to the first switching state, the first control unit 39a can allow high-concentration water to flow to the foam separator 13b via piping K3 and K4. In this case, the first waste liquid is introduced from the foam separator 13b to the first waste liquid tank 31. Alternatively, by switching the switching valve 34 to the second switching state, the first control unit 39a can introduce high-concentration water to the first waste liquid tank 31 via piping K11.

[0083] The first control unit 39a can acquire the detection result of the first water level sensor 35 based on the signal from the first water level sensor 35. Based on the detection result, the first control unit 39a can determine, for example, whether the water level of the first waste liquid tank 31 is below the first lower limit water level, whether it has reached the first upper limit water level, and so on.

[0084] The second control unit 39b shown in Figure 5 controls the supply amount of the first waste liquid and the second waste liquid to the adjustment tank 33. Similar to the first control unit 39a, the second control unit 39b is equipped with a computing device, a storage device, a communication device, etc. The second control unit 39b is connected to the valve 31a, the pump 32a, the tap water supply device 33b, the second water level sensor 36, the third water level sensor 37, and the salinity sensor 38.

[0085] The second control unit 39b can control whether or not the first waste liquid can flow from the first waste liquid tank 31 to the adjustment tank 33 by switching the state of the valve 31a by outputting a signal to the valve 31a. The second control unit 39b can also control whether or not the second waste liquid can flow from the second waste liquid tank 32 to the adjustment tank 33 by outputting a signal to the pump 32a. Furthermore, the second control unit 39b can control the tap water supply device 33b by outputting a signal to the tap water supply device 33b by switching whether or not tap water can be introduced into the adjustment tank 33.

[0086] The second control unit 39b can acquire detection results from the second water level sensor 36, the third water level sensor 37, and the salinity sensor 38 based on the signals from these sensors. Based on these detection results, the second control unit 39b can determine, for example, whether the water level in the second waste liquid tank 32 is below the second lower limit, whether the water level in the adjustment tank 33 has reached the third upper limit, and the salinity in the adjustment tank 33.

[0087] The control of the first control unit 39a will be described below.

[0088] The first control unit 39a executes the control shown in Figure 6. The control shown in Figure 6 compensates for any shortage of the first waste liquid with alternative water (high-concentration water). For the sake of explanation, the control shown in Figure 6 will be referred to as "alternative water supply control" below. Alternative water supply control is executed, for example, when introducing the first waste liquid (and high-concentration water) from the first waste liquid tank 31 to the adjustment tank 33. Alternative water supply control is terminated when the introduction of the first waste liquid into the adjustment tank 33 is stopped. When the first control unit 39a starts alternative water supply control, it proceeds to step S10.

[0089] In step S10, the first control unit 39a obtains the water level detection result of the first waste liquid tank 31 from the first water level sensor 35, and if the detection result is below the first lower limit water level (step S10: yes), proceeds to step S20. On the other hand, if the detection result is higher than the first lower limit water level (step S10: no), the first control unit 39a proceeds to step S30.

[0090] In step S20, the first control unit 39a opens the water supply path from the filtration tank 13a to the first waste liquid tank 31. As shown in Figure 7(a), in this embodiment, the first control unit 39a opens the water supply path (piping K3-K11) by switching the switching valve 34 to the second switching state. As a result, high-concentration water is introduced into the first waste liquid tank 31. When the process in step S20 is completed, the first control unit 39a executes the process in step S10 again.

[0091] In step S30, if the detection result obtained in step S10 (the current water level of the first waste liquid tank 31) is equal to or greater than the first upper limit water level (step S30: yes), the first control unit 39a proceeds to step S40. On the other hand, if the detection result is lower than the first upper limit water level (step S30: no), the first control unit 39a proceeds to step S10. In this way, the first control unit 39a repeats steps S10 and S30 when the water level of the first waste liquid tank 31 is between the first lower limit water level and the first upper limit water level.

[0092] In step S40, the first control unit 39a closes the water supply path from the filtration tank 13a to the first wastewater tank 31. As shown in Figure 7(b), in this embodiment, the first control unit 39a closes the water supply path (piping K3-K11) by switching the switching valve 34 to the first switching state. This stops the introduction of high-concentration water into the first wastewater tank 31. High-concentration water is also introduced from the filtration tank 13a to the foam separator 13b, and the first wastewater generated when the high-concentration water is purified in the foam separator 13b is introduced into the first wastewater tank 31. When the process in step S40 is completed, the first control unit 39a executes the process in step S10 again.

[0093] The first control unit 39a can introduce high-concentration water circulating in the aquaponics system 10 into the first wastewater tank 31 if the first wastewater is insufficient (step S10: yes) by performing alternative water supply control (step S20). This makes it possible to compensate for the shortage of the first wastewater with high-concentration water when it is insufficient. Therefore, even when the first wastewater is insufficient, the high-concentration water and the second wastewater can be mixed in the adjustment tank 33 to produce liquid fertilizer, and liquid fertilizer can be stably supplied to the plants in the hydroponic cultivation device 40.

[0094] Furthermore, the nutrients necessary for plants grown in the hydroponic cultivation system 40 are also present in the high-concentration water, albeit at a lower concentration than in the first wastewater. Therefore, when supplementing the first wastewater with alternative water to produce liquid fertilizer, it is possible to prevent a deficiency in the nutrients necessary for plant growth in the hydroponic cultivation system 40.

[0095] Furthermore, in this embodiment, a path (pipe K11) for introducing high-concentration water to the first waste liquid tank 31 is provided, branching off from the path (pipe K3 and K4) through which high-concentration water flows when pump 13c is driven. As a result, high-concentration water can be introduced to the first waste liquid tank 31 using pump 13c, thereby reducing the number of pumps that need to be installed and thus reducing costs.

[0096] Furthermore, in the alternative water supply control described above, when high-concentration water or the first wastewater is introduced into the first wastewater tank 31 (steps S20-S40), the amount of high-concentration water circulating in the aquaponics system 10 decreases. Therefore, the amount of high-concentration water introduced into the first wastewater tank 31 (the amount that was reduced) is separately replenished into the filtration tank 13a.

[0097] The control of the second control unit 39b will be described below.

[0098] The second control unit 39b executes the control shown in Figure 8. The control shown in Figure 8 involves introducing the first waste liquid, etc., into the adjustment tank 33 and mixing the waste liquid. For the sake of explanation, the control shown in Figure 8 will be referred to as "waste liquid mixing control" below. The waste liquid mixing control is executed as needed. For example, the waste liquid mixing control is executed when the growth system 1 is in operation. When the second control unit 39b starts the waste liquid mixing control, it proceeds to step S110.

[0099] In step S110, the second control unit 39b obtains the water level detection result of the adjustment tank 33 from the third water level sensor 37, and if the detection result is below the third lower limit water level (step S110: yes), it proceeds to step S120. On the other hand, if the detection result is higher than the third lower limit water level (step S110: no), the second control unit 39b proceeds to step S130.

[0100] In step S120, the second control unit 39b opens the water supply route from the first waste liquid tank 31 to the adjustment tank 33. As shown in Figure 9, in this embodiment, the second control unit 39b opens the water supply route (piping K10) by opening the valve 31a. As a result, the first waste liquid is introduced into the adjustment tank 33. If the first waste liquid is insufficient, high-concentration water is introduced into the first waste liquid tank 31 by the alternative water supply control described above (see Figure 6) (step S20). This high-concentration water is introduced from the first waste liquid tank 31 to the adjustment tank 33. When the process in step S120 is completed, the second control unit 39b executes the process in step S110 shown in Figure 8 again.

[0101] In step S130, the second control unit 39b proceeds to step S140 if the detection result (water level in the adjustment tank 33) obtained in step S110 is equal to or greater than the third upper limit water level (step S130: yes). On the other hand, if the detection result is lower than the third upper limit water level (step S130: no), the second control unit 39b proceeds to step S110. In this way, the second control unit 39b repeats steps S110 and S130 when the water level in the adjustment tank 33 is between the third lower limit water level and the third upper limit water level.

[0102] In step S140, the second control unit 39b closes the water supply path from the first waste liquid tank 31 to the adjustment tank 33. As shown in Figure 10(a), in this embodiment, the water supply path (piping K10) is closed by closing the valve 31a. This stops the introduction of the first waste liquid (and high-concentration water) into the adjustment tank 33. As shown in Figure 8, once the process in step S140 is completed, the second control unit 39b proceeds to step S150.

[0103] In step S150, the second control unit 39b obtains the detection result of the salinity in the adjustment tank 33 from the salinity sensor 38, and if the detection result is equal to or greater than a predetermined threshold (electrical conductivity (EC) of 9 mS / cm) (step S150: yes), proceeds to step S160. If the detection result is less than the threshold (step S150: no), the second control unit 39b proceeds to step S190.

[0104] The threshold used in step S150 is set according to the plants grown in the hydroponic cultivation system 40. For example, the threshold is set to a concentration such that no salt damage occurs when the liquid fertilizer produced in the adjustment tank 33 is supplied to the plants. In this embodiment, "9 mS / cm" is set. This is just one example, and the threshold may be set appropriately depending on the intended use of the liquid fertilizer (a mixture of the first and second waste liquids).

[0105] In step S160, the second control unit 39b obtains the water level detection result of the second waste liquid tank 32 from the second water level sensor 36, and if the detection result is below the second lower limit water level (step S160: yes), proceeds to step S180. On the other hand, if the detection result is higher than the second lower limit water level (step S160: no), the second control unit 39b proceeds to step S170.

[0106] In step S170, the second control unit 39b introduces the second waste liquid from the second waste liquid tank 32 into the adjustment tank 33. As shown in Figure 10(a), in this embodiment, the second control unit 39b drives the pump 32a to introduce the second waste liquid into the adjustment tank 33. In this way, the first waste liquid (and high-concentration water) and the second waste liquid are mixed in the adjustment tank 33. When the process in step S170 is completed, the second control unit 39b repeats the process in step S150 shown in Figure 8.

[0107] In step S180, the second control unit 39b introduces fresh water (tap water) into the adjustment tank 33. As shown in Figure 10(b), in this embodiment, the second control unit 39b operates the tap water supply device 33b to introduce tap water into the adjustment tank 33. In this way, the first waste liquid (and high-concentration water) and tap water are mixed in the adjustment tank 33. When the process in step S180 is completed, the second control unit 39b repeats the process in step S150 shown in Figure 8.

[0108] In step S190, the second control unit 39b proceeds to step S200 if the detection result obtained in step S150 is less than the threshold (EC in the adjustment tank 33 is 9 mS / cm) (step S190: yes). On the other hand, if the detection result is not less than the threshold (step S190: no), the second control unit 39b proceeds to step S150. In this way, the second control unit 39b repeats steps S150 and S190 until the detection result of the salinity sensor 38 is less than the threshold.

[0109] In step S200, the second control unit 39b controls the pump 32a and the tap water supply device 33b to stop the introduction of the second waste liquid and tap water into the adjustment tank 33. When the process in step S200 is completed, the second control unit 39b terminates the waste liquid mixing control.

[0110] The following describes a specific example of wastewater mixing control. In this example, it is assumed that wastewater mixing control is started when liquid fertilizer can be supplied from the adjustment tank 33 to the hydroponic cultivation system 40. "A state in which liquid fertilizer can be supplied" means that the water level of the liquid fertilizer stored in the adjustment tank 33 is higher than the third lower limit water level. In this example, it is also assumed that there is no shortage of the first wastewater in the first wastewater tank 31.

[0111] The liquid fertilizer stored in the adjustment tank 33 is supplied to the hydroponic cultivation system 40. As a result, the water level in the adjustment tank 33 decreases. When the water level in the adjustment tank 33 falls below the third lower limit (step S110: yes), the supply of liquid fertilizer from the adjustment tank 33 is stopped, and the first waste liquid is introduced into the adjustment tank 33 from the first waste liquid tank 31 shown in Figure 9 (step S120).

[0112] When the water level in the adjustment tank 33 rises to the third upper limit water level due to the introduction of the first waste liquid, the introduction of the first waste liquid is stopped (step S130: yes, step S140). At the same time, the adjustment tank 33 starts the operation (control) to mix the waste liquids. At this point, since only the first waste liquid of the two waste liquids has been introduced into the adjustment tank 33, the salinity in the adjustment tank 33 is relatively high (the detection result of the salinity sensor 38 is 9 mS / cm or higher) (step S150: yes). In this case, as shown in Figure 10(a), the second waste liquid is introduced into the adjustment tank 33 (step S160: no, step S170). If the second waste liquid is insufficient, tap water is introduced into the adjustment tank 33 as shown in Figure 10(b) (step S160: yes, step S180). In this way, the first waste liquid and the second waste liquid are mixed in the adjustment tank 33, and the first waste liquid is diluted with the second waste liquid (or tap water).

[0113] As the first waste liquid is diluted, the salinity in the adjustment tank 33 (detection result of salinity sensor 38) decreases. The second waste liquid, etc., is introduced until the detection result of the salinity sensor 38 becomes less than 9 mS / cm (step S190: yes, step S200). As a result, in the waste liquid mixing control, liquid fertilizer with an EC of less than 9 mS / cm (salinity below the predetermined level) is produced.

[0114] With wastewater mixing control, if the concentration of wastewater (first wastewater and second wastewater) fluctuates due to the growth status of the fish in the aquaculture tank 11, the supply amount of the second wastewater can be controlled according to the degree of the fluctuation. For example, if the salinity of the first wastewater is high due to the growth status, the supply amount of the second wastewater can be increased more than usual (when mixed at the standard ratio). This allows for appropriate adjustment of the salinity of the liquid fertilizer. For example, the concentration of the liquid fertilizer can be lowered to a level that does not cause salt damage.

[0115] Furthermore, because the second control unit 39b can automatically produce liquid fertilizer through waste liquid mixing control, the workload for producing liquid fertilizer can be reduced (reducing the amount of manpower required).

[0116] Furthermore, in the wastewater mixing control, the second wastewater is introduced after the first wastewater. By introducing the wastewater with the higher salt concentration first among the wastewaters mixed in the adjustment tank 33, it is possible to suppress changes in concentration during mixing. More specifically, if the first wastewater with a higher salt concentration is introduced after the second wastewater with a lower salt concentration, the salt concentration in the adjustment tank 33 (detection result of the salt concentration sensor 38) may rise rapidly. In contrast, if the second wastewater is introduced after the first wastewater, the salt concentration in the adjustment tank 33 is less likely to fall rapidly. Therefore, it is possible to adjust the salt concentration more easily.

[0117] Furthermore, in the wastewater mixing control, the second control unit 39b can introduce tap water into the adjustment tank 33 if the second wastewater is insufficient (step S160: yes) (step S180). This allows the shortage of the second wastewater to be compensated for with tap water. Therefore, even if the second wastewater is insufficient, the first wastewater can be diluted with tap water in the adjustment tank 33 to produce liquid fertilizer, and liquid fertilizer can be stably supplied to the plants in the hydroponic cultivation device 40.

[0118] As described above, the wastewater mixing system 30 according to this embodiment comprises: an adjustment tank 33 (mixing unit) that mixes a first wastewater generated in an aquaponics system 10 that raises fish and plants using high-concentration water with a higher salinity than freshwater, and a second wastewater generated in a hydroponic cultivation device 20 (freshwater growing unit) that grows plants using freshwater; a salinity sensor 38 (concentration detection unit) capable of detecting the salinity of the mixture (liquid fertilizer) of the first and second wastewaters; a valve 31a and a pump 32a (first supply unit) capable of supplying the first and second wastewaters to the adjustment tank 33; and a control unit 39 that performs wastewater mixing control (first control) by controlling the valve 31a and the pump 32a to adjust the amount of the first wastewater or the amount of the second wastewater supplied to the adjustment tank 33 according to the detection result of the salinity sensor 38.

[0119] By configuring it in this way, it is possible to make effective use of waste liquid.

[0120] Furthermore, the mixture is supplied to plants grown in a location different from the aquaponics system 10 and the hydroponic cultivation device 20 (a nutrient solution cultivation device 40), and the control unit 39 (second control unit 39b) adjusts the supply amount in the wastewater mixing control so that the detection result of the salinity sensor 38 does not exceed a threshold (9 mS / cm) set according to the plants to which the mixture is supplied (steps S150 to S200 shown in Figure 8).

[0121] By configuring it in this way, the salt concentration can be appropriately adjusted according to the plant. For example, the salt concentration can be lowered to a level that does not cause salt damage.

[0122] Furthermore, in the wastewater mixing control, the control unit 39 (second control unit 39b) supplies either the first wastewater or the second wastewater to the adjustment tank 33 (steps S110 to S140), and then supplies the other of the first wastewater or the second wastewater to the adjustment tank 33 (steps S150 to S200).

[0123] This configuration makes it easier to adjust the salinity. For example, by introducing the second wastewater after the first wastewater, the salinity can be gradually reduced in the adjustment tank 33, making it easier to adjust the salinity.

[0124] Furthermore, in the wastewater mixing control, the control unit 39 (second control unit 39b) supplies the first wastewater to the adjustment tank 33, and then supplies the second wastewater to the adjustment tank 33 until the detection result of the salinity sensor 38 falls below the threshold (steps S110 to S200).

[0125] By configuring it in this way, rapid fluctuations in salt concentration can be suppressed, and the salt concentration can be adjusted more easily.

[0126] Furthermore, the wastewater mixing system 30 is further equipped with a switching valve 34 (second supply unit) capable of supplying the high-concentration water circulating in the aquaponics system 10 to the adjustment tank 33, and the control unit 39 (first control unit 39a) controls the switching valve 34 to supply the high-concentration water to the adjustment tank 33 when the first wastewater is insufficient, thereby performing alternative water supply control (second control) to compensate for the shortage of the first wastewater with the high-concentration water.

[0127] By configuring it in this way, any shortage of the first waste liquid can be compensated for with high-concentration water.

[0128] Furthermore, the waste liquid mixing system 30 further comprises a first waste liquid tank 31 (storage unit) capable of storing the first waste liquid and connected to the adjustment tank 33 so that the first waste liquid can be introduced into the adjustment tank 33, and a first water level sensor 35 (introduction detection unit) that detects whether or not the first waste liquid can be introduced from the first waste liquid tank 31 to the adjustment tank 33. The control unit 39 (first control unit 39a) controls the switching valve 34 to supply the high-concentration water to the adjustment tank 33 when the first water level sensor 35 detects that the first waste liquid cannot be introduced in the alternative water supply control (step S10: yes, step S20).

[0129] By configuring it in this way, the switching valve 34 can be appropriately controlled according to the detection result of the first water level sensor 35.

[0130] Furthermore, the first water level sensor 35 detects whether or not the first waste liquid can be introduced into the first waste liquid tank 31, based on the first waste liquid tank 31.

[0131] This configuration makes it easier to determine whether or not there is a shortage of the first waste liquid compared to determining whether or not there is a shortage of the first waste liquid based on information (water level, etc.) obtained from the adjustment tank 33.

[0132] Furthermore, the wastewater mixing system 30 is further equipped with a tap water supply device 32b (third supply unit) capable of supplying fresh water (tap water) to the adjustment tank 33, and the control unit 39 (second control unit 39b) controls the tap water supply device 32b to supply fresh water to the adjustment tank 33 when the second wastewater is insufficient, thereby performing a third control (steps S160 to S180) to compensate for the shortage of the second wastewater with fresh water (tap water).

[0133] By configuring it in this way, any shortage of the second waste liquid can be compensated for with fresh water.

[0134] Furthermore, the hydroponic cultivation apparatus 20 according to this embodiment is one form of the freshwater growth unit according to the present invention. Furthermore, the adjustment tank 33 according to this embodiment is one form of the mixing unit according to the present invention. Furthermore, the salt concentration sensor 38 according to this embodiment is one embodiment of the concentration detection unit according to the present invention. Furthermore, the valve 31a and pump 32a according to this embodiment are one form of the first supply unit according to the present invention. Furthermore, the wastewater mixing control according to this embodiment is one form of implementing the first control according to the present invention. Furthermore, the switching valve 34 according to this embodiment is one embodiment of the second supply unit relating to the present invention. Furthermore, the alternative water supply control according to this embodiment is one form of implementing the second control according to the present invention. Furthermore, the first waste liquid tank 31 according to this embodiment is one form of the storage unit according to the present invention. Furthermore, the first water level sensor 35 according to this embodiment is one form of implementation of the introduction detection unit according to the present invention. Furthermore, the tap water supply device 32b according to this embodiment is one form of the third supply unit according to the present invention.

[0135] Although embodiments of the present invention have been described above, the present invention is not limited to the above configuration, and various modifications are possible within the scope of the invention as described in the claims.

[0136] For example, the first and second waste liquids mixed in the adjustment tank 33 are intended to be used as liquid fertilizer, but the use of the waste liquids is not limited to liquid fertilizer and can be changed as appropriate.

[0137] Furthermore, although the water treatment device 13 is provided with a filtration tank 13a and a foam separator 13b, this is just one example, and the configuration of the water treatment device 13 may be changed as needed. For example, if the filtration tank 13a (physical filtration, biological filtration) can sufficiently purify the high-concentration water, the foam separator 13b may be omitted.

[0138] Furthermore, while the first and second waste liquids are stored in the first waste liquid tank 31 and the second waste liquid tank 32, respectively, the system is not limited to this. For example, the first waste liquid may be introduced into the adjustment tank 33 without being stored in a tank, and an amount of the second waste liquid corresponding to the amount introduced may be introduced from the second waste liquid tank 32 into the adjustment tank 33. Thus, it is also possible to configure the system so that only one of the first or second waste liquids is stored in a tank.

[0139] Furthermore, in the wastewater mixing control, the first wastewater is introduced into the adjustment tank 33 first, followed by the second wastewater. However, the timing of introducing the first and second wastewater is not particularly limited. For example, the second wastewater may be introduced into the adjustment tank 33 in the order of second wastewater, then first wastewater, or the first and second wastewater may be introduced into the adjustment tank 33 simultaneously. If the second wastewater is introduced into the adjustment tank 33 in the order of second wastewater, then first wastewater, the supply amount of the first wastewater to the adjustment tank 33 is adjusted so that the EC in the adjustment tank 33 does not exceed 9 mS / cm. If the first and second wastewater are introduced into the adjustment tank 33 simultaneously, the supply amounts of the first and second wastewater to the adjustment tank 33 are adjusted so that the EC in the adjustment tank 33 does not exceed 9 mS / cm. Thus, the control unit 39 only needs to adjust the supply amount of at least one of the first waste liquid or the second waste liquid according to the salinity in the adjustment tank 33 (detection result of the salinity sensor 38).

[0140] Furthermore, in the alternative water supply control, it is determined whether or not there is a shortage of first wastewater (whether it can be introduced into the adjustment tank 33) based on the water level in the first wastewater tank 31 (step S10 shown in Figure 6). However, this is just one example, and it is possible to determine whether or not there is a shortage of first wastewater in a different way than in this embodiment. For example, it is also possible to determine whether or not there is a shortage of first wastewater based on the weight of the first wastewater tank 31. Alternatively, it is also possible to determine whether or not there is a shortage of first wastewater based on the amount of first wastewater flowing from the first wastewater tank 31 to the adjustment tank 33.

[0141] Furthermore, in the alternative water supply control, if the first wastewater is insufficient, the shortage is to be compensated for with high-concentration water (step S110: yes, step S120). However, the water used in place of the first wastewater is not limited to high-concentration water.

[0142] Furthermore, in the alternative water supply control system, high-concentration water is introduced into a different component (first wastewater tank 31) from the adjustment tank 33 (see Figure 7(a)), but the destination of the high-concentration water is not limited to this. For example, it is also possible to introduce the high-concentration water into the adjustment tank 33.

[0143] Furthermore, in the wastewater mixing control, the determination of whether or not there is a shortage of second wastewater is made based on the water level in the second wastewater tank 32 (step S160 shown in Figure 8), but this is just one example, and the determination of whether or not there is a shortage of second wastewater may be made in a different way than in this embodiment. For example, it is also possible to determine whether or not there is a shortage of second wastewater based on the weight of the second wastewater tank 32 or the amount of second wastewater flowing into the adjustment tank 33.

[0144] Furthermore, in the wastewater mixing control, if the second wastewater is insufficient, the deficiency is to be supplemented with tap water (step S160: yes, step S180). However, the water used in place of the second wastewater is not limited to tap water, as long as it is fresh water.

[0145] Furthermore, in the wastewater mixing control system, tap water is introduced into the adjustment tank 33 (see Figure 10(b)), but the destination of the tap water is not limited to this. For example, it is also possible to introduce tap water into other components (e.g., the second wastewater tank 32) that are connected to the adjustment tank 33 in a way that allows for the introduction of tap water.

[0146] In this embodiment, alternative water supply control and wastewater mixing control are performed by separate devices (first control unit 39a and second control unit 39b), but this is just one example, and alternative water supply control and wastewater mixing control may be performed by a common device. [Explanation of Symbols]

[0147] 10 Aquaponics Systems 20 Hydroponic cultivation systems 30 Wastewater mixing system 31a Valve 32a Pump 33 Adjustment tank 38 Salt concentration sensor 39 Control Unit

Claims

1. A mixing unit that mixes the first wastewater generated in an aquaponics system that raises fish and plants using high-concentration water with a higher salinity than freshwater, and the second wastewater generated in a freshwater growing unit that uses freshwater to grow plants, A concentration detection unit capable of detecting the salt concentration of the mixture of the first waste liquid and the second waste liquid, A first supply unit capable of supplying the first waste liquid and the second waste liquid to the mixing unit, A control unit that performs a first control by controlling the first supply unit to adjust at least one of the amount of the first waste liquid supplied to the mixing unit, or the amount of the second waste liquid supplied to the mixing unit, according to the detection result of the concentration detection unit, Equipped with, Waste liquid mixing system.

2. The aforementioned mixture is This is supplied to plants grown in a location different from the aquaponics system and the freshwater growing section. The control unit, In the first control, the supply amount is adjusted so that the detection result of the concentration detection unit does not exceed a threshold set according to the plant to which the mixture is supplied. The waste liquid mixing system according to claim 1.

3. The control unit, In the first control, after supplying either the first waste liquid or the second waste liquid to the mixing unit, the other of the first waste liquid or the second waste liquid is supplied to the mixing unit. The waste liquid mixing system according to claim 2.

4. The control unit, In the first control, after supplying the first waste liquid to the mixing unit, the second waste liquid is supplied to the mixing unit until the detection result of the concentration detection unit falls below the threshold. The waste liquid mixing system according to claim 3.

5. The aquaponics system further comprises a second supply unit capable of supplying the high-concentration water circulating in the aquaponics system to the mixing unit, The control unit, When the first waste liquid is insufficient, the second supply unit is controlled to supply the high-concentration water to the mixing unit, thereby performing a second control to compensate for the shortage of the first waste liquid with the high-concentration water. A waste liquid mixing system according to any one of claims 1 to 4.

6. A storage unit capable of storing the first waste liquid and connected to the mixing unit so that the first waste liquid can be introduced into the mixing unit, An introduction detection unit for detecting whether or not the first waste liquid can be introduced from the storage unit to the mixing unit, Furthermore, it is equipped with, The control unit, In the second control, if the introduction detection unit detects that the first waste liquid cannot be introduced, the second supply unit is controlled to supply the high-concentration water to the mixing unit. The waste liquid mixing system according to claim 5.

7. The aforementioned introduction detection unit, Based on the water level in the storage section, it is detected whether or not the first waste liquid can be introduced. The waste liquid mixing system according to claim 6.

8. The system further comprises a third supply unit capable of supplying fresh water to the mixing unit, The control unit, If the second waste liquid is insufficient, the third supply unit is controlled to supply fresh water to the mixing unit, thereby performing a third control to compensate for the shortage of the second waste liquid with fresh water. A waste liquid mixing system according to any one of claims 1 to 4.

Images