Water quality inspection device and breeding system

Abstract

To provide a water quality inspection device that determines water quality on the basis of the amount of microorganisms fixed to a filter medium.SOLUTION: A water quality inspection device for a breeding system 10 including a breeding tank 20, includes a water quality control tank 40 connected to the breeding tank 20 and through which breeding water circulating in the breeding system 10 is circulated, a filter medium 42 stored in the water quality control tank 40, an exterior water source 70 that subjects the filter medium 42 to a germicidal treatment, a turbidimeter 44 that measures turbidity of the breeding water in the water quality control tank 40 after the exterior water source 70 subjects the filter medium 42 to the germicidal treatment, and a control device 80 that determines water quality on the basis of the turbidity.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The technology disclosed in this specification relates to a water quality inspection device and a breeding system using the same.

Background Art

[0002] When breeding aquatic organisms in breeding tanks such as aquariums for ornamental fish, aquariums, and fish farms, it is important to keep the water quality such as pH and salinity concentration suitable for the aquatic organisms. However, the water quality of the breeding water changes due to various factors. Among them, the influence of pollution caused by food residues and excreta of aquatic organisms is remarkable. Therefore, it is generally practiced to circulate the breeding water between the breeding tank and the filtration device and filter the breeding water to improve the water quality. In addition, in order to confirm that the water quality adjustment by the filtration device is properly performed, a device for automatically detecting changes in water quality has also been proposed (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, filtration in a filtration device is classified into physical filtration for physically filtering food residues and the like, chemical filtration for adsorbing organic compounds and the like on a filter medium having adsorbability such as activated carbon, and biological filtration for decomposing and detoxifying organic substances by microorganisms fixed on the filter medium. Among them, it is known that the importance of biological filtration is very high in order to maintain good water quality over a long period of time. However, since a method for simply quantifying the microorganisms fixed on the filter medium has not yet been established, it is difficult to directly determine the effect of biological filtration based on the amount of the microorganisms and the like.

[0005] The technology disclosed in this specification aims to provide a water quality inspection device that determines water quality based on the amount of microorganisms fixed on a filter medium.

Means for Solving the Problems

[0006] One example is a water quality inspection device for a breeding system including a breeding tank, which is connected to the breeding tank and has a container through which breeding water circulating in the breeding system flows, a filter medium housed in the container, sterilizing means for sterilizing the filter medium, turbidity measuring means for measuring the turbidity of at least one of the breeding water in the container and the breeding water that has passed through the container after the sterilizing means sterilizes the filter medium, and water quality determination means for determining water quality based on the turbidity. It is a water quality inspection device comprising the above.

[0007] According to this configuration, the water quality inspection device determines water quality based on the turbidity of the breeding water after sterilizing the filter medium. Since the microorganisms fixed on the filter medium die and become free due to the sterilization treatment of the filter medium, and the turbidity of the breeding water increases, water quality can be determined based on the turbidity of the breeding water after sterilization treatment, enabling water quality determination based on the amount of microorganisms.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0009] <Embodiment 1> Hereinafter, Embodiment 1 of the technology disclosed in this specification will be described with reference to the drawings. The breeding system 10 according to this embodiment is a system for breeding aquatic organisms on land. In the present disclosure, aquatic organisms mean animals and plants that live in water or on the water's edge. The breeding system 10 also includes a water quality inspection device for the breeding system 10 that inspects the water quality of the breeding water circulating within the system. Since the water quality inspection device according to the present disclosure utilizes a part of the components of the breeding system 10 itself, in the following description, the components of both will not be clearly distinguished and will be described as an integrated unit. FIG. 1 is a schematic diagram of the breeding system 10 of the present disclosure. Each arrow in FIG. 1 indicates the flow direction of the fluid within the breeding system 10.

[0010] [Breeding System 10] As shown in FIG. 1, the breeding system 10 includes a breeding tank 20 for breeding aquatic organisms, a filtration device 30 for filtering the breeding water, a water quality management tank 40 for temporarily storing the breeding water for water quality inspection, and a microorganism addition device 60 for adding microorganisms to the breeding water. The breeding system 10 also includes a control device 80 that controls the entire breeding system 10.

[0011] [Breeding Tank 20] The breeding tank 20 stores breeding water inside for breeding aquatic organisms. The types of aquatic organisms mainly include cultured fish and ornamental fish, but are not limited to these, and may be, for example, plants cultivated hydroponically. The breeding tank 20 is also connected to the filtration device 30 via a sewage passage 22 and is configured to be able to discharge the contaminated breeding water towards the filtration device 30.

[0012] [Filtration Device 30] The filtration device 30 is filled with a filter medium 31 made of a plurality of types of materials suitable for physical filtration, chemical filtration, and biological filtration, respectively. The type of the filter medium 31 is not particularly limited, and conventionally known ones can be used. Among them, since microorganisms contributing to biological filtration such as nitrifying bacteria are usually aerobic, from the viewpoint of a large surface area where microorganisms can settle and easy passage of fluid, the filter medium for biological filtration is preferably made of a porous material such as ceramics or gravel. The filtration device 30 is connected to the breeding tank 20 via a purified water passage 32, and the breeding water filtered by the filtration device 30 is circulated to the breeding tank 20 via the purified water passage 32.

[0013] In the purified water passage 32, a three-way valve 34 and a solenoid valve 36 are provided in this order along the direction from the filtration device 30 toward the breeding tank 20. The three-way valve 34 and the solenoid valve 36 are each electrically connected to the control device 80 and are controlled to open and close. Further, the three-way valve 34 is integrated with an electric pump 35, and the breeding water circulates between the breeding tank 20 and the filtration device 30 by driving and controlling the electric pump 35.

[0014] [Water quality management tank 40] The water quality management tank 40 houses a filter medium 42 inside. The filter medium 42 is formed of a porous material on which microorganisms performing biological filtration can easily settle. A turbidimeter 44 is provided in the water quality management tank 40 and is configured to measure the turbidity of the breeding water stored in the water quality management tank 40. The turbidimeter 44 is electrically connected to the control device 80, and the timing of measurement and the like are controlled. Further, the measured value by the turbidimeter 44, that is, the turbidity of the breeding water, is transmitted from the turbidimeter 44 to the control device 80. In the present disclosure, the water quality management tank 40 corresponds to a "container", and the turbidimeter 44 corresponds to a "turbidity measuring means".

[0015] A branch passage 46 branched from the purified water passage 32 is connected to the water quality management tank 40. Further, the water quality management tank 40 is connected to the breeding tank 20 via a return passage 48. Thereby, a part of the breeding water circulating in the breeding system 10 flows through the inside of the water quality management tank 40 via the branch passage 46 and the return passage 48.

[0016] A solenoid valve 50 is provided in the branch passage 46, and a solenoid valve 52 is provided in the return passage 48. The solenoid valves 50 and 52 are each electrically connected to the control device 80 and are controlled to open and close. Further, a discharge passage 54 branches off from between the water quality management tank 40 and the solenoid valve 52 in the return passage 48. The other end of the discharge passage 54 is open to the outside, and is configured to be able to discharge the breeding water in the breeding system 10 to the outside. A solenoid valve 56 is provided in the discharge passage 54 and is controlled to open and close by the control device 80.

[0017] [Microorganism addition device 60] The microorganism addition device 60 is provided along the sewage passage 22 and is configured such that the breeding water flows through the inside of the microorganism addition device 60. The microorganism addition device 60 stores microorganisms for biological filtration in a dormant state, and when it receives a signal from the control device 80, it adds the dormant microorganisms to the breeding water flowing through the inside. In the present disclosure, the microorganism addition device 60 corresponds to "water quality adjustment means".

[0018] [External water source 70] The three-way valve 34 is connected to the external water source 70 via the introduction passage 38. The external water source 70 supplies tap water containing chlorine. The external water source 70 usually does not communicate with the purified water passage 32, but when the three-way valve 34 is switched by the control device 80 and the external water source 70 communicates with the purified water passage 32, the tap water is introduced into the purified water passage 32. In the present disclosure, the external water source 70 corresponds to "sterilization means".

[0019] [Control device 80] The control device 80 includes a memory that stores various control programs and a processor for executing the control programs. The control device 80 is electrically connected to each electric device of the breeding system 10 and controls each electric device based on the control program. In the present disclosure, the control device 80 corresponds to "water quality determination means".

[0020] <Water quality determination process> Next, the water quality determination process in this embodiment will be described with reference to FIGS. 1 to 3. FIG. 2 is a diagram showing the operating states of the electric devices during water quality determination and the change in turbidity in the water quality management tank 40. In FIG. 2, the turbidity when a sufficient amount of microorganisms have settled on the filter medium 42 is indicated by a solid line, and the turbidity when the amount of microorganisms is insufficient is indicated by a dashed line. FIG. 3 is a diagram showing the relationship between the passage of time after the sterilization treatment and the measured turbidity.

[0021] The water quality determination process is carried out at regular intervals, for example, once a week. As shown in FIG. 2, in the normal state (T0), the electric pump 35 is operating, the three-way valve 34 blocks the communication with the external water source 70, and the breeding water is flowing through the water purification passage 32. The solenoid valves 36, 50, and 52 are open, and the solenoid valve 56 is closed. As a result, the breeding water circulates within the breeding system 10 via the breeding tank 20 and the filtration device 30. A part of the circulating breeding water flows into the water quality management tank 40 via the branch passage 46 and then returns to the breeding tank 20 from the return passage 48.

[0022] When the water quality determination process is started (T1), the solenoid valve 50 and the solenoid valve 52 are closed, preventing the inflow of breeding water into the water quality management tank 40 and the outflow from the water quality management tank 40. In this state, the turbidity of the breeding water in the water quality management tank 40 is measured using the turbidimeter 44.

[0023] After measuring the turbidity of the breeding water (T2), the three-way valve 34 blocks the flow from the upstream to the downstream in the water purification passage 32 and is switched to connect the external water source 70 and the downstream side of the water purification passage 32. Also, the solenoid valve 36 is closed and the solenoid valve 50 is opened. As a result, tap water is supplied from the external water source 70 into the breeding system 10 and flows into the water quality management tank 40 through the introduction passage 38, the water purification passage 32, and the branch passage 46. Then, the filter medium 42 is sterilized by the chlorine contained in the tap water, and the microorganisms that had settled on the filter medium 42 are killed. Since the dead microorganisms are released from the filter medium 42, the turbidity of the breeding water in the water quality management tank 40 increases with the passage of time.

[0024] When a certain amount of tap water flows into the water quality management tank 40 (T3), the electric pump 35 is stopped. In this state, the turbidity of the breeding water in the water quality management tank 40 is measured at regular intervals over a predetermined period by the turbidimeter 44.

[0025] When the measurement of turbidity is completed (T4), the electric pump 35 is operated, and the three-way valve 34 shuts off the communication with the external water source 70 and is switched so that the breeding water flows through the water purification passage 32 from the upstream side to the downstream side. Also, the electromagnetic valve 56 is opened. As a result, the breeding water flows out to the outside through the water purification passage 32, the branch passage 46, the water quality management tank 40, and the discharge passage 54, and the liquid containing chlorine and dead microorganisms remaining in these passages and in the water quality management tank 40 is discharged to the outside. When a certain amount of breeding water has been discharged to the outside (T5), the electromagnetic valves 36 and 52 are opened and the electromagnetic valve 56 is closed, returning to the normal state.

[0026] Thereafter, the control device 80 calculates the difference between the turbidity of the breeding water measured before the sterilization treatment (between T1 and T2) and the turbidity of the breeding water measured after the sterilization treatment (between T3 and T4). Note that since the turbidity after the sterilization treatment increases according to the amount of dead microorganisms released from the filter medium 42, it usually increases with the passage of time. Therefore, as shown in FIG. 3, a plurality of turbidities (T35 and T36) whose mutual deviation is within a predetermined range are selected from among the turbidities (T31 to T36) measured at regular intervals, and the average value is used as the turbidity after the sterilization treatment. When using a plurality of turbidities whose mutual deviation is within a predetermined range, in addition to selecting from a plurality of turbidities measured over time as described above, it may also be selected from turbidities measured simultaneously at a plurality of locations in the water quality management tank 40.

[0027] Since the change amount of the turbidity before and after the sterilization treatment is mainly due to the amount of microorganisms killed and released by the sterilization treatment, when the change amount is equal to or greater than a predetermined value (see the solid line in FIG. 2), the control device 80 determines that the amount of microorganisms fixed on the filter medium 42 is sufficient and the water quality is good. On the other hand, when the change amount is less than the predetermined value (see the broken line in FIG. 2), it is determined that the amount of microorganisms is insufficient and the water quality is poor.

[0028] When a determination result indicating that the quality of the breeding water is poor is obtained, the microorganism addition device 60 adds dormant microorganisms to the breeding water based on a control signal from the control device 80. When the microorganisms are added to the breeding water, they shift from the dormant state to the active state and settle on the filter medium 31 in the filtration device 30 or the filter medium 42 in the water quality management tank 40 in the process of circulating within the breeding system 10. As a result, since the amount of microorganisms in the breeding system 10 increases, the water quality of the breeding water can be improved.

[0029] <Advantages of Embodiment 1> According to the above embodiment, since the water quality is determined based on the change in turbidity caused by the sterilization treatment of the filter medium 42, it is possible to determine the water quality based on the amount of microorganisms that had settled on the filter medium 42.

[0030] In addition, since the turbidity after the sterilization treatment is calculated based on a plurality of turbidities whose mutual deviation is within a predetermined range, it becomes less susceptible to the influence of variations in turbidity caused by the flow of the breeding water in the water quality management tank 40 or the like, and the determination accuracy is improved.

[0031] Also, when it is determined that the quality of the breeding water is poor, the microorganism addition device 60 adds dormant microorganisms to the breeding water, thereby increasing the amount of microorganisms contributing to biological filtration. As a result, the water quality can be easily improved.

[0032] <Embodiment 2> Subsequently, Embodiment 2 of the present disclosure will be described with reference to FIGS. 4 and 5. Since Embodiment 2 is a modification of the configuration of Embodiment 1, the same reference numerals will be given to the same configurations and the description thereof will be omitted. FIG. 4 is a schematic diagram showing a breeding system 110 according to Embodiment 2, and each arrow in the figure indicates the flow direction of the fluid within the breeding system 110.

[0033] [Structure of Breeding System 110] As shown in FIG. 4, the breeding system 110 includes a breeding tank 20, a filtration device 30, a microorganism addition device 60, and a control device 80. The filtration device 30 includes a plurality of filtration units connected in parallel to each other. The number of filtration units is not particularly limited, but is preferably 5 or more (FIG. 4 shows two filtration units 30A and 30B). The filtration units 30A and 30B are filled with filter media 31. In the present disclosure, the filtration units 30A and 30B correspond to "containers".

[0034] The breeding tank 20 is connected to the filtration device 30 via a sewage passage 122, and a microorganism addition device 60 and an electric pump 35 are provided along the sewage passage 122. The sewage passage 122 branches into a first sewage passage 122A and a second sewage passage 122B between the microorganism addition device 60 and the filtration device 30, and is connected to the filtration units 30A and 30B, respectively. Further, a first purified water passage 132A and a second purified water passage 132B extending from the filtration units 30A and 30B, respectively, merge to form a purified water passage 132 and are connected to the breeding tank 20. Thereby, when the electric pump 35 is driven, the breeding water in the breeding tank 20 flows into one of the filtration units 30A and 30B through the sewage passage 122, the first sewage passage 122A, and the second sewage passage 122B, is filtered, and then is circulated to the breeding tank 20 through the first purified water passage 132A, the second purified water passage 132B, and the purified water passage 132.

[0035] A first branch passage 140A branches from the first purified water passage 132A, and a three-way valve 142A is provided at the confluence of the first purified water passage 132A and the first branch passage 140A. Similarly, a second branch passage 140B branches from the second purified water passage 132B, and a three-way valve 142B is provided at the confluence of the second purified water passage 132B and the second branch passage 140B. The first branch passage 140A and the second branch passage 140B merge to form a branch passage 140. A heater 144 and a turbidimeter 146 are provided on the branch passage 140.

[0036] The downstream end of the branch passage 140 branches into a first return passage 148A and a second return passage 148B. The first return passage 148A is connected to the first sewage passage 122A, and a three-way valve 150A is provided at the confluence point. Also, the second return passage 148B is connected to the second sewage passage 122B, and a three-way valve 150B is provided at the confluence point.

[0037] A discharge passage 152 and an introduction passage 154 are respectively connected to the branch passage 140 on the downstream side of the turbidimeter 146. A three-way valve 156 is installed at the confluence point of the discharge passage 152 and the branch passage 140. The other end of the discharge passage 152 is open to the outside, and the breeding water flowing through the branch passage 140 can be discharged to the outside. On the other hand, a three-way valve 158 is provided at the confluence point of the introduction passage 154 and the branch passage 140. The other end of the introduction passage 154 is connected to the breeding water supply source 160, and by communicating the introduction passage 154 and the branch passage 140, new breeding water can be introduced into the breeding system 110 from the outside. Note that the three-way valves 142A, 142B, 150A, 150B, 156, 158 are respectively electrically connected to the control device 80 and the communication direction is controlled. Also, the three-way valve 158 is provided with an integrated electric pump 162, and the electric pump 162 is also driven and controlled by the control device 80.

[0038] [Heater 144] The heater 144 is configured to heat the breeding water flowing inside based on a signal from the control device 80. By supplying the heated breeding water to the filtration units 30A, 30B, the filter medium 31 can be sterilized. Since the microorganisms contributing to biological filtration die due to a rapid temperature rise, it is preferable that the heater 144 is configured to raise the temperature of the breeding water by 15 to 20°C. In the present disclosure, the heater 144 corresponds to a "sterilization means".

[0039] [Turbidimeter 146] The turbidimeter 146 is configured to continuously or intermittently measure the turbidity of the breeding water flowing inside. The turbidimeter 146 is electrically connected to the control device 80. After measuring the turbidity of the breeding water based on a signal from the control device 80, it transmits the measurement result to the control device 80.

[0040] <Water quality determination process> Subsequently, the water quality determination process in this embodiment will be described with reference to FIGS. 4 and 5. FIG. 5 is a diagram showing the operating states of each electric member during water quality determination and the change in the turbidity of the breeding water flowing through the turbidimeter 146. In FIG. 5, the turbidity when the amount of microorganisms fixed on the filter medium 31 is sufficient is indicated by a solid line, and the turbidity when the amount of microorganisms is insufficient is indicated by a broken line. Also, the directions of each three-way valve in FIG. 5 mean the communication directions of each three-way valve shown in FIG. 4, more specifically, the flow direction of the breeding water.

[0041] The water quality determination process is carried out at regular intervals, for example, once a week. Also, the number of filtration units targeted in one water quality determination process is one, and the plurality of filtration units included in the filtration device 30 become the targets of the water quality determination process in a predetermined order. Here, the water quality determination process targeting the filtration unit 30A will be described as an example.

[0042] As shown in FIG. 5, in the normal state (T0), the electric pump 162 is stopped, the three-way valves 142A and 150A communicate in the left-right direction, and the three-way valves 156 and 158 communicate in the right-left direction. Since the electric pump 35 is always operating, the breeding water circulates between the breeding tank 20 and the filtration device 30 via the sewage passage 122 and the purified water passage 132. Also, since the communication between the branch passage 140 and the sewage passage 122 and the purified water passage 132 is blocked, the breeding water circulating between the breeding tank 20 and the filtration device 30 does not flow into the branch passage 140.

[0043] When the water quality determination process starts (T1), the three-way valve 150A is switched to connect the first return passage 148A and the downstream side of the first sewage passage 122A, and the three-way valve 142A is switched to connect the upstream side of the first purified water passage 132A and the first branch passage 140A. Also, the electric pump 162 and the heater 144 are operated. As a result, the breeding water heated by the heater 144 flows into the filtration unit 30A through the branch passage 140, the first return passage 148A, and the first sewage passage 122A, and circulates by being returned to the heater 144 through the first purified water passage 132A and the first branch passage 140A. When the breeding water heated to a high temperature flows into the filtration unit 30A, the filter medium 31 in the filtration unit 30A is sterilized, and the microorganisms fixed on the filter medium 31 die and become free. As a result, when the breeding water passes through the filtration unit 30A, the dead bodies of the microorganisms are mixed into the breeding water, and the turbidity of the breeding water increases. The turbidimeter 146 continuously or intermittently measures the turbidity of the breeding water flowing inside over a predetermined period after the start of the water quality determination process. In this state, since the breeding tank 20 and the filtration unit 30B communicate with each other and the communication with the heater 144 is blocked, the heated breeding water is prevented from flowing into the breeding tank 20 and the filtration unit 30B, and the circulation of the breeding water between the breeding tank 20 and the filtration unit 30B is maintained.

[0044] When a predetermined time has elapsed since the start of the water quality determination process (T2), the heater 144 is stopped, the three-way valve 158 is switched to connect the introduction passage 154 and the downstream side of the branch passage 140, and the three-way valve 156 is switched to connect the upstream side of the branch passage 140 and the discharge passage 152. As a result, breeding water at room temperature or a temperature suitable for the aquatic organisms being bred is supplied from the breeding water supply source 160 through the introduction passage 154. Then, the newly supplied breeding water is discharged to the outside through the first return passage 148A, the first sewage passage 122A, the filtration unit 30A, the first purified water passage 132A, the first branch passage 140A, the branch passage 140, and the discharge passage 152. Thereby, the high-temperature breeding water and the dead bodies of the microorganisms remaining inside each passage and the filtration unit 30A and the like can be discharged to the outside.

[0045] When a predetermined amount of the breeding water is discharged to the outside (T3), the electric pump 162 is stopped and each of the three-way valves 142A, 150A, 156, and 158 is returned to the initial state.

[0046] Thereafter, the control device 80 calculates the change amount between the turbidity of the breeding water measured at the start of the sterilization treatment (T1) and the turbidity of the breeding water measured after the sterilization treatment (the last measured value between T1 and T2). When the change amount is equal to or greater than a predetermined value (see the solid line in FIG. 5), the control device 80 determines that the amount of microorganisms contributing to biological filtration is sufficient and the water quality is good. On the other hand, when the change amount is less than the predetermined value (see the broken line in FIG. 5), it is determined that the amount of microorganisms is insufficient and the water quality is poor. Note that instead of the turbidity measured last after the sterilization treatment, a plurality of turbidities whose mutual deviation is within a predetermined range may be selected and the average value thereof may be used as the turbidity after the sterilization treatment.

[0047] When it is determined that the water quality of the breeding water is poor, the control device 80 operates the microorganism addition device 60 and adds dormant microorganisms to the breeding water passing through the microorganism addition device 60. The microorganisms become active in the breeding water and settle on the filter medium 31 in the filter units 30A and 30B while circulating in the breeding system 110 including the breeding tank 20 and the filtration device 30. As a result, the amount of microorganisms in the breeding system 110 increases, so that the efficiency of biological filtration is improved and the water quality of the breeding water can be improved.

[0048] <Advantages of Embodiment 2> According to the above embodiment, since the water quality is determined based on the change in turbidity caused by the sterilization treatment of the filter medium 31, the water quality can be determined based on the amount of microorganisms fixed on the filter medium 31 in the filtration device 30. In addition, since only one of the plurality of filter units sterilized in one water quality determination process is the target, the decrease in filtration performance due to the sterilization treatment of the filter medium 31 can be minimized. Further, during the water quality determination process, the filter unit that is not the target of the process is kept in communication with the breeding tank 20, and the electric pump 35 is also kept in the operating state at all times, so that the breeding water circulating between the breeding tank 20 and the filtration device 30 can be filtered even during the water quality determination process.

[0049] In addition, since the sterilization treatment of the filter medium 31 is performed by heating with the heater 144, there is no need to introduce a sterilizing component such as chlorine into the breeding system 110 for the sterilization treatment. Therefore, it is possible to eliminate the possibility that microorganisms and aquatic organisms in the breeding tank 20 are affected by the sterilizing component remaining in the breeding system 110 after the water quality determination treatment.

[0050] [Other Embodiments] The technology disclosed in this specification is not limited to the above-described embodiments. For example, the sterilization treatment of the filter medium may be performed by a change in salt concentration, rapid cooling of the breeding water, an increase in the amount of dissolved carbon dioxide, an electric shock, ultraviolet irradiation, etc., instead of the introduction of chlorine or the heating of the breeding water. For example, when performing the sterilization treatment by ultraviolet irradiation in Embodiment 1, it is preferable to install a UV sterilization lamp capable of irradiating ultraviolet rays of a predetermined wavelength in the water quality management tank 40, and the filter medium 42 is made of a transparent ceramic that transmits ultraviolet rays. Also, in that case, the apparatus can be simplified by using the same light source for the UV sterilization lamp and the turbidimeter 44.

[0051] In the above-described embodiment, the change amount of the turbidity before and after the sterilization treatment is compared with a predetermined value in the water quality determination treatment, but the turbidity after the sterilization treatment may be compared with a predetermined value. Thereby, the water quality determination treatment can be simplified and the treatment time can be shortened.

[0052] In the above-described embodiment, when the change amount of the turbidity before and after the sterilization treatment is less than a predetermined value, microorganisms are added to the breeding water. However, the change amount may be compared with a plurality of predetermined values, and the amount of microorganisms to be added may be adjusted according to the change amount of the turbidity. Thereby, an appropriate amount of microorganisms can be added according to the amount of microorganisms fixed on the filter medium.

[0053] In addition, the method of water quality adjustment is not limited to the addition of microorganisms, and may be carried out by adjusting pH, salt concentration, temperature, dissolved oxygen concentration, etc., or these may be used in combination with the addition of microorganisms. Since the microorganisms in the breeding system decrease due to various factors, an apparatus for measuring and adjusting pH, etc. may be installed, and when the water quality is determined to be poor, the factors inhibiting the growth of microorganisms may be identified and improved.

Explanation of Signs

[0054] 10,110 Breeding system 20 Breeding tank 30 Filtration device 30A,B Filtration unit (container) 31,42 Filter medium 40 Water quality management tank (container) 44,146 Turbidimeter (turbidity measuring means) 60 Microorganism addition device (water quality adjustment means) 70 External water source (sterilization means) 80 Control device (water quality determination means) 144 Heater (sterilization means)

Claims

1. A water quality inspection device for a breeding system equipped with a breeding tank, comprising: A container connected to the breeding tank through which breeding water containing microorganisms for biological filtration circulating within the breeding system flows; Filter media housed in the container; Sterilization means for sterilizing the filter media to kill the microorganisms; Turbidity measurement means for measuring the turbidity of at least one of the breeding water containing the killed microorganisms in the container and the breeding water containing the killed microorganisms that has passed through the container after the sterilization means has sterilized the filter media; Water quality determination means for determining that the better the water quality of the breeding water in the breeding tank, the greater the turbidity; A water quality inspection device comprising the above.

2. The water quality inspection device according to Claim 1, wherein: The sterilization means performs sterilization treatment of the filter media with ultraviolet light of a predetermined wavelength; The sterilization means and the turbidity measurement means use the same light source. A water quality inspection device.

3. The water quality inspection device according to Claim 1 or 2, wherein: The determination of the water quality by the water quality determination means is performed based on a plurality of turbidities whose mutual deviation is within a predetermined range. A water quality inspection device.

4. A breeding system equipped with the water quality inspection device according to Claim 1 or 2, comprising: Water quality adjustment means for adjusting the water quality of the breeding water based on the determination result by the water quality determination means. A breeding system.

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