System for monitoring water quality

Abstract

Provided is technology that can suppress complexity in a system for monitoring water quality in land-based farming. This system for monitoring water quality in land-based farming is characterized by comprising: pipes respectively communicating with a plurality of water tanks; first valves provided to the pipes; a merging unit that merges a plurality of pipes at a point downstream of the plurality of pipes; a second valve provided downstream of the merging unit; a measurement unit for measuring water quality; and a control unit, wherein the control unit controls the first valves and the second valve so that breeding water in the water tank is stored in the merging unit, and the measurement unit measures the water quality of the breeding water stored in the merging unit.

Description

Water Quality Monitoring System

[0001] The present disclosure relates to water quality monitoring systems.

[0002] Patent Document 1 discloses a water quality measurement system for measuring the water quality of rearing water for rearing aquatic organisms. This water quality measurement system includes an introduction section for introducing rearing water, an addition section for adding a base to the introduced rearing water, and a diaphragm-type ion sensor for measuring the concentration of a target substance contained in the rearing water after the base has been added.

[0003] Japanese Patent Application Laid-Open No. 2021-13908

[0004] When land-based aquaculture is carried out using multiple aquariums, it is desirable to monitor the water quality of each of the aquariums. However, if the water quality measurement system described in Patent Document 1 is applied to each of the multiple aquariums, there is a risk that the system will become complicated. For this reason, there has been a demand for a technology that can prevent the system from becoming too complicated in a water quality monitoring system for land-based aquaculture.

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one aspect of the present disclosure, a water quality monitoring system is provided. This water quality monitoring system is a water quality monitoring system for land-based aquaculture, comprising pipes respectively communicating with a plurality of aquariums, first valves provided in the pipes, a junction downstream of the plurality of pipes that joins the plurality of pipes, a second valve provided downstream of the junction, a measurement unit for measuring water quality, and a control unit, wherein the control unit controls the first and second valves to cause rearing water in the aquariums to be stored in the junction, and the measurement unit measures the water quality of the rearing water stored in the junction. According to this aspect of the water quality monitoring system, rearing water is stored in the junction downstream of the plurality of pipes and the water quality is measured, thereby reducing the number of measurement units required. As a result, the system can be made less complex.

[0007] (2) In the water quality monitoring system described in (1) above, the confluence may include a manhole into which the breeding water can overflow. In this water quality monitoring system, the confluence includes a manhole, making it easy to measure the water quality even in a case where breeding water is sampled and the water quality is measured. As a result, the complexity of the system can be further reduced.

[0008] (3) In the water quality monitoring system described in (1) or (2) above, the piping may be a drain pipe for draining the breeding water from the aquarium. In this form of water quality monitoring system, the piping also serves as a drain pipe for draining the breeding water from the aquarium, thereby preventing excessive withdrawal of breeding water from the aquarium for water quality measurement.

[0009] (4) In the water quality monitoring system according to any one of (1) to (3), the measurement unit may measure the ammonium ion concentration. In this water quality monitoring system, the measurement unit measures the ammonium ion concentration, making it possible to manage the degree of contamination of the breeding water for each aquarium.

[0010] (5) In the water quality monitoring system according to any one of (1) to (4), the breeding water may be seawater. This water quality monitoring system can monitor water quality even when the breeding water is seawater containing various ions.

[0011] (6) In the water quality monitoring system described in any one of (1) to (5) above, the control unit may open the second valve to drain the stored breeding water from the confluence, then close the second valve, and then open the first valve provided in the piping communicating with the aquarium for which water quality measurement has not been completed to store the breeding water in the confluence. With this type of water quality monitoring system, when multiple aquariums are to be monitored, the water quality of the breeding water in the aquarium for which water quality measurement has not been completed can be measured sequentially, thereby suppressing a decrease in monitoring efficiency.

[0012] (7) In the water quality monitoring system described in (6) above, the junction may be cleaned after the stored breeding water is drained from the junction. According to this form of water quality monitoring system, the junction is cleaned after the breeding water is drained from the junction, which makes it possible to suppress a decrease in the accuracy of water quality measurement and a decrease in cleaning efficiency.

[0013] (8) In the water quality monitoring system according to (6) above, which is dependent on (2) above, the control unit may open the first valve provided in the pipe communicating with the aquarium for which water quality measurement has not been completed, and allow the rearing water to overflow in the manhole for a certain period of time, and then store the rearing water in the confluence. With this type of water quality monitoring system, the inside of the manhole can be washed with the rearing water to be measured, thereby preventing a decrease in the accuracy of water quality measurement.

[0014] (9) In the water quality monitoring system described in any one of (1) to (8) above, the confluence includes a first confluence and a second confluence, the first confluence is connected to the piping that communicates with the aquarium in which the more immature individuals are kept among the plurality of aquariums, and the second confluence is connected to the piping that communicates with the aquarium in which the more mature individuals are kept among the plurality of aquariums, and the measurement unit may measure the water quality of the breeding water stored in the first confluence and the water quality of the breeding water stored in the second confluence, respectively. This type of water quality monitoring system is equipped with a first confluence section that stores the breeding water from the aquarium where more immature individuals are kept, and a second confluence section that stores the breeding water from the aquarium where more mature individuals are kept, thereby preventing the breeding water from the aquarium where more immature individuals are kept from mixing and being discharged.

[0015] (10) The water quality monitoring system according to any one of (1) to (9) above may further include a plurality of the aquariums. According to this form of water quality monitoring system, in a system including a plurality of aquariums, it is possible to omit installing a measuring unit for each aquarium, thereby suppressing the complexity of the system.

[0016] (11) In the water quality monitoring system described in (4) above, the measurement unit may have a diaphragm electrode. In this water quality monitoring system, the measurement unit that measures the ammonium ion concentration has a diaphragm electrode, which reduces the influence of substances other than ammonia, thereby preventing a decrease in the accuracy of water quality measurement.

[0017] The present disclosure can be realized in various forms, such as a land-based aquaculture system, a method for manufacturing a water quality monitoring system, a water quality monitoring method, a method for producing aquatic organisms, a method for cultivating aquatic organisms, etc.

[0018] An explanatory diagram showing a schematic configuration of a water quality monitoring system. An explanatory diagram for explaining the configuration of a confluence unit, a measurement unit, and a control unit. A flowchart showing an example of control of a water quality monitoring system. An explanatory diagram showing a schematic configuration of a water quality monitoring system of a comparative example. An explanatory diagram showing a schematic configuration of a water quality monitoring system of a second embodiment.

[0019] A. First Embodiment: A-1. System Configuration: FIG. 1 is an explanatory diagram illustrating a schematic configuration of a water quality monitoring system 100 according to one embodiment of the present disclosure. The water quality monitoring system 100 is a system that monitors the water quality of the rearing water in a plurality of aquariums 200 in which aquatic organisms are reared in land-based aquaculture. The water quality monitoring system 100 constitutes part of a land-based aquaculture system 300. For ease of explanation, the aquariums 200 included in the land-based aquaculture system 300 are indicated by dashed lines in FIG. 1. Target aquatic organisms for land-based aquaculture include, but are not limited to, crustaceans such as shrimp and crabs, fish, shellfish, aquatic animals, marine mammals, and seaweed. The aquatic organisms may be immature individuals such as juvenile shrimp or juvenile fish, or mature individuals.

[0020] The aquarium 200 is configured to store rearing water therein and rears the aquatic organisms to be cultured. The rearing water is not particularly limited and is selected depending on the aquatic organisms to be cultured. Examples of the rearing water include, but are not limited to, fresh water such as fresh water and well water, and salty water such as brackish water, seawater, and artificial seawater. The land-based aquaculture system 300 may be a closed circulation system in which all or almost all of the rearing water discharged from the aquarium 200 is circulated and returned to the aquarium 200, or a semi-closed circulation system in which a portion of the rearing water discharged from the aquarium 200 is circulated and returned to the aquarium 200. For ease of illustration, FIG. 1 shows the areas of eight of the multiple aquariums 200 included in the land-based aquaculture system 300.

[0021] The water quality monitoring system 100 of this embodiment includes a pipe 20 , a first valve 30 , a confluence section 40 , a second valve 50 , a measurement section 60 , and a control section 80 .

[0022] A pipe 20 is provided for each aquarium 200 and is connected to each of the multiple aquariums 200. A first valve 30 is provided in the pipe 20. The first valve 30 is configured, for example, by an electromagnetic valve, and its open / close state is controlled by a control unit 80. When the first valve 30 is closed, the breeding water in that aquarium 200 is prevented from flowing out through the pipe 20. When the first valve 30 is open, the breeding water in that aquarium 200 is allowed to flow out through the pipe 20. In the example shown in FIG. 1 , a pump 210 is provided between the pipe 20 and the aquarium 200 to pump the breeding water from the aquarium 200. In the example shown in FIG. 1 , the pipe 20 is a drain pipe for draining the breeding water from the aquarium 200, and the pump 210 is a drainage pump.

[0023] The confluence 40 joins the multiple pipes 20 downstream of the multiple pipes 20. A detailed description of the confluence 40 will be provided later. The second valve 50 is provided downstream of the confluence 40. The second valve 50 is configured, for example, by an electromagnetic valve, and its open / close state is controlled by the control unit 80. When the second valve 50 is closed, rearing water flowing in through the pipes 20 is stored in the confluence 40. When the second valve 50 is open, rearing water is discharged from the confluence 40. In the example shown in FIG. 1 , the downstream side of the second valve 50 is connected to a wastewater storage section 220. The wastewater storage section 220 stores wastewater for a certain period of time. Note that the wastewater storage section 220 may be omitted, and the downstream side of the second valve 50 may be directly connected to a sewer system.

[0024] 2 is an explanatory diagram for explaining the configuration of the confluence section 40, the measurement section 60, and the control section 80. For ease of explanation, FIG. 2 illustrates one of the multiple pipes 20 and one water tank 200 connected thereto.

[0025] In this embodiment, the confluence section 40 includes a manhole 44 through which rearing water can overflow. The manhole 44 is open vertically upward and can store a certain amount of rearing water. The inclusion of the manhole 44 in the confluence section 40 allows rearing water to overflow, facilitating water quality measurement even in a configuration in which rearing water is sampled for measurement. This reduces the complexity of the system. Furthermore, the interior of the manhole 44 may be washed by overflowing rearing water from the aquarium 200 being measured. Washing the interior of the manhole 44 prevents the rearing water from the aquarium 200 being measured from mixing with the rearing water from the aquarium 200 for which measurement has been completed, thereby reducing the accuracy of water quality measurement. The rearing water overflowing from the manhole 44 flows through the overflow line 46 to the wastewater storage section 220. When the second valve 50 provided downstream of the manhole 44 is closed, the breeding water is stored in the manhole 44, and when the second valve 50 is opened, the breeding water stored in the manhole 44 is drained into the drainage reservoir 220. For example, after the second valve 50 is closed and the breeding water from the aquarium 200 to be measured is filled into the confluence 40, the second valve 50 is opened to drain the water, thereby washing the inside of the confluence 40 together.

[0026] The measurement unit 60 measures the water quality of the rearing water stored in the junction 40. In this embodiment, the measurement unit 60 measures the water quality of the rearing water by sampling and processing the rearing water stored in the junction 40. In this embodiment, the measurement unit 60 measures the ammonium ion concentration. The measurement unit 60 in this embodiment includes a water sampling unit 62, a processing unit 64, and a communication unit 66. The water sampling unit 62 has a pump (not shown) and samples the rearing water stored in the junction 40 for measurement. The processing unit 64 has a sensor (not shown), such as a diaphragm-type ion sensor, and measures the water quality by adding a reagent such as a base to the sampled rearing water. In this embodiment, the processing unit 64 has a diaphragm-type electrode. Therefore, the measurement unit 60 has an ammonia sensor including a diaphragm-type electrode. Ammonia contained in the sampled rearing water is gasified, passes through a diaphragm (not shown), and dissolves in the internal liquid, and its concentration is measured. Therefore, with a diaphragm electrode, only ammonia contained in the rearing water is gasified and reaches the electrode, thereby reducing the effects of substances other than ammonia contained in the rearing water and preventing a decrease in the accuracy of water quality measurement. More specifically, when using seawater as the rearing water, for example, and the rearing water contains a large amount of sodium chloride or other impurities, false detection due to unintended substances can be prevented. The communication unit 66 is configured to be able to communicate with the communication unit 86 of the control unit 80 wirelessly or via a wired connection. The communication unit 66 receives water quality measurement instructions from the control unit 80 and outputs water quality measurement results to the control unit 80.

[0027] The control unit 80 is a computer including a CPU (Central Processing Unit) 82, a memory unit 84, and a communication unit 86, and is capable of performing various calculations, control, and information processing. The CPU 82 controls various operations in the water quality monitoring system 100 by executing programs pre-stored in the memory unit 84. More specifically, the control unit 80 (CPU 82) controls the first valve 30 and the second valve 50, which are provided for each aquarium 200, to store and discharge the breeding water from the specific aquarium 200 in the confluence unit 40 (manhole 44). In this embodiment, the control unit 80 (CPU 82) controls the first valve 30 and the second valve 50 via a programmable logic controller (PLC) (not shown). However, the open / closed states of the first valve 30 and the second valve 50 may be controlled by any other method, such as a relay sequence. The control unit 80 sends a water quality measurement instruction to the measurement unit 60 via the communication unit 86. The water quality measurement instructions may include, for example, a calibration instruction before measuring the ammonium ion concentration, a measurement instruction, and a cleaning instruction after the measurement. The memory unit 84 includes, for example, a memory such as a ROM or RAM. The memory unit 84 stores identification information related to the aquarium 200, such as the aquarium number and type for identifying the aquarium 200. The type of aquarium 200 is not particularly limited, but examples include a juvenile shrimp tank for the early stage of aquaculture, an intermediate tank for the middle stage of aquaculture, and a shipping tank for the final stage of aquaculture. The memory unit 84 also stores the water quality measurement results acquired by the communication unit 86 in association with each aquarium 200. The communication unit 86 is configured to be able to communicate with external devices, such as the communication unit 66 of the measurement unit 60, wirelessly or via a wired connection.

[0028] A-2. Control of the Water Quality Monitoring System: Figure 3 is a flowchart showing an example of the control of the water quality monitoring system 100. In the example shown in Figure 3, control begins with the first valve 30 and the second valve 50 closed. The control unit 80 determines whether a predetermined set time has arrived (step S110). If it is determined that the predetermined set time has not arrived (step S110: NO), step S110 is repeated. On the other hand, if it is determined that the predetermined set time has arrived (step S110: YES), the control unit 80 outputs a drain command to the PLC to drain the rearing water from the manhole 44 of the confluence unit 40 (step S115). When the drain command is output, the second valve 50 is opened, and the water is drained (step S120).

[0029] The control unit 80 determines whether the drainage is complete (step S125). The completion of drainage may be detected, for example, by a water level sensor installed inside the manhole 44, or may be determined by the passage of a predetermined period of time. If the completion of drainage is not determined (step S125: NO), the process returns to step S120 and the drainage operation continues. If the completion of drainage is determined (step S125: YES), the control unit 80 outputs a cleaning command to the PLC to clean the manhole 44 of the confluence unit 40 (step S130). When the cleaning command is output, cleaning is performed (step S135). In the cleaning, the second valve 50 is closed and the first valve 30 installed in the piping 20 communicating with the aquarium 200 to be measured is opened, thereby washing the manhole 44 of the confluence unit 40 with the breeding water. Thereafter, the second valve 50 is opened and the breeding water used for the co-washing is drained, thereby completing the washing. Note that the washing may be performed by opening both the second valve 50 and the first valve 30, or may be performed using fresh water or the like instead of the breeding water in the aquarium 200 to be measured.

[0030] The control unit 80 determines whether the cleaning is complete (step S140). The cleaning completion may be determined, for example, by the passage of a predetermined period of time. If the cleaning is not complete (step S140: NO), the process returns to step S135 and the cleaning operation continues. If the cleaning is complete (step S140: YES), the control unit 80 outputs a water injection command to the PLC to store the rearing water in the aquarium 200 to be measured in the manhole 44 of the confluence unit 40 (step S145). When the water injection command is output, water is injected (step S150). During the water injection, the second valve 50 is closed, and the first valve 30 provided in the piping 20 communicating with the aquarium 200 to be measured is opened.

[0031] The control unit 80 determines whether or not the water pouring is complete (step S155). Whether or not the water pouring is complete may be detected, for example, by a water level sensor or the like provided inside the manhole 44, or the water pouring completion state may be determined when a predetermined period of time has elapsed. If it is determined that the water pouring is not complete (step S155: NO), the process returns to step S150 and the water pouring operation continues. When the water pouring is complete, the first valve 30, which was open until then, is closed.

[0032] If it is determined that the water supply is complete (step S155: YES), the control unit 80 outputs a calibration, measurement, and cleaning instruction to the measurement unit 60 to measure the ammonium ion concentration (step S160). This calibration, measurement, and cleaning instruction causes the measurement unit 60 to perform calibration, measurement, and cleaning (step S165). In step S165, the processing unit 64 calibrates the sensor, and then the water sampling unit 62 samples the rearing water stored in the manhole 44. The processing unit 64 then measures the water quality, and once the measurement is complete, the sensor is cleaned. The water quality measurement results are output to the control unit 80 via the communication units 66 and 86, and the memory unit 84 stores the water quality measurement results together with the identification information of the aquarium 200.

[0033] The control unit 80 determines whether the calibration, measurement, and cleaning are complete (step S170). Whether the calibration, measurement, and cleaning are complete may be determined, for example, by whether the communication unit 86 has received the water quality measurement results. If it is determined that the calibration, measurement, and cleaning are not complete (step S170: NO), the process returns to step S165 and continues.

[0034] If it is determined that the calibration, measurement, and cleaning are complete (step S170: YES), the control unit 80 determines whether there is a water quality measurement instruction for the next aquarium 200 (step S175). Whether there is a water quality measurement instruction for the next aquarium 200 may be determined, for example, based on the aquarium number stored in the memory unit 84. For example, if the program is programmed to perform measurements in ascending order of aquarium number, it may determine whether there is an aquarium 200 to be measured after the aquarium 200 for which water quality measurement has been completed. If it is determined that there is a water quality measurement instruction for the next aquarium 200 (step S175: YES), the control unit 80 proceeds to step S115, where it outputs a drainage instruction to the PLC to drain the breeding water from the manhole 44 of the confluence unit 40 (step S115). On the other hand, if it is determined that there is no water quality measurement instruction for the next aquarium 200 (step S175: NO), the control unit 80 returns to step S110 and waits.

[0035] According to the water quality monitoring system 100 of the present embodiment described above, rearing water is collected downstream of the multiple pipes 20 at the junction 40 where the multiple pipes 20 join, and the water quality is measured. This eliminates the need to install multiple measurement units 60, for example, for each aquarium 200. As a result, the number of measurement units 60 can be reduced, thereby preventing the system from becoming too complex. Furthermore, because the pipe 20 also serves as a drain pipe for draining rearing water from the aquarium 200, excessive intake of rearing water from the aquarium 200 for water quality measurement can be prevented. As a result, it is possible to prevent water quality measurement from becoming impossible due to the aquarium 200 exceeding its allowable water intake volume, and it is also possible to omit controlling the water intake volume so as not to exceed the allowable water intake volume of the aquarium 200. Furthermore, because the water quality monitoring system 100 monitors the ammonium ion concentration, it is possible to manage the degree of contamination of the rearing water for each aquarium 200. Furthermore, the water quality monitoring system 100 can monitor the water quality of rearing water even when the rearing water is seawater containing various ions.

[0036] Furthermore, in the flow described above, the control unit 80 opens the second valve 50 (steps S115, S120), drains the rearing water stored in the junction 40 from the junction 40 (step S125: YES), and then closes the second valve 50. Thereafter, the control unit 80 opens the first valve 30 provided in the piping 20 communicating with the aquarium 200 for which water quality measurement has not been completed, which was identified in step S175 (steps S145, S150), to store the rearing water in the junction 40. According to this control flow, when multiple aquariums 200 are to be monitored, the water quality of the rearing water in the aquariums 200 for which water quality measurement has not been completed can be measured sequentially, thereby suppressing a decrease in monitoring efficiency.

[0037] In the above-described flow, the control unit 80 drains the accumulated rearing water from the junction 40 (step S125: YES) and then cleans the junction 40 (steps S130 and S135). This control flow prevents a decrease in the accuracy of water quality measurement and a decrease in cleaning efficiency. In the above-described flow, the interior of the junction 40 is cleaned using the rearing water to be measured. This allows for co-washing with the rearing water to be measured, further preventing a decrease in the accuracy of water quality measurement. In the above-described flow, when a predetermined set time is identified (step S110: YES), a drain command is output to the PLC (step S115), and the water is drained (step S120). Therefore, because drainage and cleaning are performed before measurement, measurement can be performed even when rearing water remains in the junction 40 due to an unexpected error or the like. For example, even if the control unit 80 stops while the manhole 44 is filled with rearing water, the manhole 44 is first drained, allowing the state of the manhole 44 to be reset.

[0038] B. Comparative Example: FIG. 4 is an explanatory diagram showing a schematic configuration of a water quality monitoring system 500 of the comparative example. The water quality monitoring system 500 of the comparative example does not include a confluence section. In the water quality monitoring system 500 of the comparative example, a water sampling section 562 of the measurement unit 560 is provided for each aquarium 200, and the entire system has multiple measurement units 560. The water quality monitoring system 500 of the comparative example has multiple measurement units 560, making the system more complex. As a result, the initial and running costs of the system increase. Furthermore, in the water quality monitoring system 500 of the comparative example shown in FIG. 4, culture water is sampled separately from wastewater. In such a configuration, in order to avoid excessive intake of culture water from the aquarium 200 for water quality measurement, it is necessary to control the intake so as not to exceed the allowable water intake of the aquarium 200. 4, the measuring unit 560 has four water sampling units 562, with one measuring unit 560 provided for each of the four aquariums 200, resulting in an excessive length of the water sampling units 562. As a result, an excessive amount of rearing water from the aquariums 200 is sampled, exceeding the allowable water intake volume of the aquariums 200, making it impossible to measure the water quality.

[0039] In contrast, according to the water quality monitoring system 100 of the above embodiment shown in Figure 1, the breeding water of the aquarium 200 to be measured is stored in the confluence section 40 and the water quality is measured, so the number of measurement sections 60 to be installed can be reduced and the system can be simplified.

[0040] C. Second Embodiment: Figure 5 is an explanatory diagram showing a schematic configuration of a water quality monitoring system 100a of the second embodiment. The water quality monitoring system 100a of the second embodiment differs from the water quality monitoring system 100 of the first embodiment in the configuration of the confluence section 40a and the measurement section 60a. Since the other configuration is the same as that of the water quality monitoring system 100 of the first embodiment, the same components are designated by the same reference numerals and detailed description thereof will be omitted.

[0041] The land-based aquaculture system 300a equipped with the water quality monitoring system 100a of the second embodiment includes multiple tanks 200a of different types. More specifically, the system includes multiple fry shrimp tanks 250a, multiple intermediate tanks 260a, and multiple shipping tanks 270a. The fry shrimp tanks 250a contain less mature shrimp than those in the intermediate tanks 260a and shipping tanks 270a. When cultivating imported fry shrimp, it is generally desirable to store the wastewater from the fry shrimp tanks 250a for a predetermined period of time. For this reason, it is desirable to separate the wastewater discharged from the fry shrimp tanks 250a from the wastewater discharged from the intermediate tanks 260a and shipping tanks 270a. The land-based aquaculture system 300a in the second embodiment is provided with a first wastewater storage section 221a for storing wastewater from the fry shrimp tank 250a, and a second wastewater storage section 222a for storing wastewater from the intermediate tank 260a and the shipping tank 270a. For ease of illustration, Fig. 5 shows the areas of nine of the multiple tanks 200a included in the land-based aquaculture system 300a.

[0042] The confluence 40a in the second embodiment includes a first confluence 41a and a second confluence 42a. The first confluence 41a is connected to a pipe 20 that communicates with a fry shrimp tank 250a, which contains more immature shrimp among the multiple aquariums 200a. Therefore, the first confluence 41a stores the rearing water from the fry shrimp tank 250a. A second valve 51a is provided downstream of the first confluence 41a and is connected to a first drainage reservoir 221a. The second confluence 42a is connected to a pipe 20 that communicates with an intermediate tank 260a and a shipping tank 270a, which contain more mature shrimp among the multiple aquariums 200a. Therefore, the second confluence 42a stores the rearing water from the intermediate tank 260a and the shipping tank 270a. A second valve 52a is provided downstream of the second confluence 42a and is connected to a second wastewater reservoir 222a.

[0043] The measuring unit 60a has two water sampling units 62a. One of the two water sampling units 62a samples the rearing water stored in the first junction 41a. The other of the two water sampling units 62a samples the rearing water stored in the second junction 42a. With this configuration, the measuring unit 60a measures the water quality of the rearing water stored in the first junction 41a and the water quality of the rearing water stored in the second junction 42a.

[0044] The water quality monitoring system 100a of the second embodiment described above includes a first confluence 41a that stores the rearing water of the aquarium 200a in which immature individuals are reared (juvenile shrimp tank 250a) and a second confluence 42a that stores the rearing water of the aquarium 200a in which more mature individuals are reared (intermediate tank 260a, shipping tank 270a), thereby preventing the rearing water of the aquarium 200a in which immature individuals are reared and the rearing water of the aquarium 200a in which more mature individuals are reared from mixing and being discharged. In this way, the water quality monitoring system 100a may be provided with multiple confluences 40a depending on the application, etc.

[0045] D. Modifications: The configuration of the water quality monitoring system 100, 100a in the above embodiment is merely an example and can be modified in various ways. For example, the piping 20 in the above embodiment also serves as a drain pipe for draining breeding water from the aquarium 200, 200a. However, the piping is not limited to a drain pipe and may be any piping, such as a water intake pipe provided for water quality measurement. Furthermore, for example, the measurement unit 60, 60a in the above embodiment measures ammonium ion concentration. Instead of ammonium ion, the present disclosure may measure mineral concentrations such as calcium, magnesium, and sodium. Alternatively, the measurement unit 60, 60a may measure dissolved oxygen concentration, carbon dioxide concentration, nitrate concentration, oxidation-reduction potential, conductivity, pH, temperature, etc. The measurement unit 60, 60a may have sensors appropriate for the water quality measurement items, and the water sampling unit 62, 62a may be omitted depending on the water quality measurement method. Furthermore, although the confluence unit 40, 40a in the above embodiment includes a manhole 44, the manhole 44 may be omitted. In an embodiment in which the manhole 44 is omitted, any configuration that can collect the breeding water from the multiple aquariums 200, 200a in one location may be used, and for example, the confluence 40, 40a may be composed of piping only. Also, for example, the water quality monitoring system 100, 100a may be equipped with the aquariums 200, 200a.

[0046] The control of the water quality monitoring system 100, 100a in the above embodiment is merely an example and can be modified in various ways. For example, water quality monitoring is not limited to a predetermined time, but may be performed whenever a predetermined period of time has elapsed, or when any predetermined condition is met, such as after the breeding water in the aquarium 200, 200a has been replaced. Furthermore, for example, water quality monitoring is not limited to sequentially measuring the water quality of the breeding water in the aquarium 200, 200a for which water quality measurement has not been completed, but may be performed according to a predetermined program.

[0047] Furthermore, for example, in the above control flow, the interior of the confluence section 40, 40a is cleaned by controlling the open / close states of the second valves 50, 51a, and 52a. However, the present disclosure is not limited to this. For example, steps S130, S135, and S140 may be omitted, and cleaning may be performed during water injection (step S150). More specifically, in step S150, rearing water may be allowed to overflow into the manhole 44 for a certain period of time to be washed together with the rearing water, and then stored in the confluence section 40 (manhole 44). That is, the control unit 80 may close the first valve 30 after allowing rearing water to overflow from the manhole 44 of the confluence section 40, 40a for a certain period of time. This certain period may be, for example, a predetermined time or a period during which a predetermined amount of rearing water overflows. This control flow also allows the interior of the manhole 44 to be washed together with the rearing water to be measured, thereby preventing a decrease in the accuracy of water quality measurement.

[0048] The present invention is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit of the present invention. For example, the technical features in the embodiments and examples corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate.

[0049] 20...piping, 30...first valve, 40, 40a...junction, 41a...first junction, 42a...second junction, 44...manhole, 46...overflow line, 50, 51a, 52a...second valve, 60, 60a...measuring unit, 62, 62a...water sampling unit, 64...processing unit, 66...communication unit, 80...control unit, 82...CPU, 84...storage unit, 86...communication unit, 100, 100 a...water quality monitoring system, 200, 200a...aquarium, 210...pump, 220...wastewater storage section, 221a...first wastewater storage section, 222a...second wastewater storage section, 250a...juvenile shrimp tank, 260a...intermediate tank, 270a...shipping tank, 300, 300a...land-based aquaculture system, 500...water quality monitoring system, 560...measuring section, 562...water sampling section

Claims

1. A water quality monitoring system for land-based aquaculture comprising: pipes each connected to a plurality of aquariums; a first valve provided on the pipes; a junction section that joins the plurality of pipes downstream of the plurality of pipes; a second valve provided downstream of the junction section; a measurement section for measuring water quality; and a control section, wherein the control section controls the first valve and the second valve to store culture water from the aquariums in the junction section, and the measurement section measures the water quality of the culture water stored in the junction section.

2. A water quality monitoring system as claimed in claim 1, characterized in that the confluence includes a manhole into which the breeding water can overflow.

3. A water quality monitoring system as claimed in claim 1, characterized in that the piping is a drain pipe for draining the breeding water from the aquarium.

4. A water quality monitoring system as claimed in claim 1, characterized in that the measuring unit measures an ammonium ion concentration.

5. The water quality monitoring system according to claim 1, characterized in that the breeding water is seawater.

6. A water quality monitoring system as described in claim 1, characterized in that the control unit opens the second valve, drains the stored breeding water from the junction, then closes the second valve, and then opens the first valve provided in the piping communicating with the aquarium for which water quality measurement has not been completed, causing the breeding water to be stored in the junction.

7. The water quality monitoring system according to claim 6, characterized in that the stored breeding water is drained from the confluence, and then the confluence is cleaned.

8. A water quality monitoring system as described in claim 6 dependent on claim 2, characterized in that the control unit opens the first valve provided in the piping communicating with the aquarium for which water quality measurement has not been completed, allowing the breeding water to overflow in the manhole for a certain period of time, and then storing the water in the junction.

9. A water quality monitoring system as described in claim 1, characterized in that the junction includes a first junction and a second junction, the first junction is connected to the piping that communicates with the aquarium in which more immature individuals are kept among the plurality of aquariums, and the second junction is connected to the piping that communicates with the aquarium in which more mature individuals are kept among the plurality of aquariums, and the measurement unit measures the water quality of the breeding water stored in the first junction and the water quality of the breeding water stored in the second junction, respectively.

10. The water quality monitoring system according to claim 1, further comprising a plurality of said water tanks.

11. A water quality monitoring system as claimed in claim 4, characterized in that the measuring section has a diaphragm-type electrode.

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