JP7682830B2 - Water quality testing equipment and breeding system - Google Patents

Description

The technology disclosed in this specification relates to a water quality testing device and a breeding system using the same.

When raising aquatic organisms in breeding tanks such as ornamental fish tanks, fish preserves, and fish farms, it is important to maintain water quality, such as pH and salinity, in a state suitable for the organisms. However, the quality of the breeding water can change due to various factors, with contamination by residual food and excrement from the aquatic organisms being particularly noticeable. For this reason, it is common to circulate the breeding water between the breeding tank and a filtration device, filtering the breeding water to improve the water quality. A device has also been proposed that automatically detects changes in water quality to ensure that the water quality is being appropriately adjusted by the filtration device (Patent Document 1).

Japanese Patent Application Publication No. 7-280793

Generally, filtration in filtration devices is classified into physical filtration, which physically filters out food residues, chemical filtration, which adsorbs organic compounds onto adsorbent filter media such as activated carbon, and biological filtration, which decomposes and detoxifies organic matter using microorganisms that have settled on the filter media. Of these, biological filtration is known to be extremely important in maintaining good water quality for long periods of time. However, because a simple method for quantifying the microorganisms that have settled on the filter media has not yet been established, it is difficult to directly assess the effectiveness of biological filtration based on the amount of the microorganisms.

The technology disclosed in this specification aims to provide a water quality testing device that determines water quality based on the amount of microorganisms that have settled on a filter medium.

One example is a water quality testing device for a breeding system having a breeding tank, comprising: a container connected to the breeding tank through which breeding water circulating within the breeding system flows; a filter medium contained in the container; sterilization means for sterilizing the filter medium; a 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 sterilization means has sterilized the filter medium; and a water quality determining means for determining the water quality based on the turbidity.
This is a water quality testing device.

With this configuration, the water quality testing device judges the water quality based on the turbidity of the rearing water after the filter medium has been sterilized. The sterilization of the filter medium kills and liberates the microorganisms that had been attached to the filter medium, causing the turbidity of the rearing water to increase. Therefore, by judging the water quality based on the turbidity of the rearing water after the sterilization, it is possible to judge the water quality based on the amount of microorganisms.

FIG. 1 is a schematic diagram of a breeding system according to a first embodiment of the present disclosure. FIG. 2 is a diagram showing the operating state of each electrically-driven device in the rearing system of FIG. 1 . FIG. 13 is a graph showing the relationship between the time elapsed after sterilization treatment and the turbidity of the breeding water. FIG. 13 is a schematic diagram of a breeding system according to a second embodiment of the present disclosure. FIG. 5 is a diagram showing the operating state of each electrically-driven device in the rearing system of FIG. 4 .

<Embodiment 1>
Hereinafter, a first embodiment 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 this disclosure, aquatic organisms refer to animals and plants that live in water or near water. The breeding system 10 also includes a water quality testing device for the breeding system 10 that tests the quality of the breeding water circulating in the system. Since the water quality testing device according to the present disclosure uses some of the components of the breeding system 10 itself, the following description will not clearly distinguish between the two components and will describe them as being integrated. FIG. 1 is a schematic diagram of the breeding system 10 according to the present disclosure. Each arrow in FIG. 1 indicates the flow direction of a fluid in the breeding system 10.

[Breeding system 10]
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 control tank 40 for temporarily storing the breeding water for testing the water quality, and a microorganism adding device 60 for adding microorganisms to the breeding water. The breeding system 10 also includes a control device 80 for controlling the entire breeding system 10.

[Breeding tank 20]
The breeding tank 20 stores breeding water therein for breeding aquatic organisms. The types of aquatic organisms are mainly farmed fish and ornamental fish, but are not limited thereto, and may be, for example, hydroponically grown plants. The breeding tank 20 is connected to a filtration device 30 via a wastewater passage 22, and is configured to be able to discharge dirty breeding water toward the filtration device 30.

[Filtering device 30]
The filter device 30 is filled with filter media 31 made of a plurality of materials suitable for physical filtration, chemical filtration, and biological filtration. The type of filter media 31 is not particularly limited, and any conventionally known filter media can be used. In particular, since microorganisms that contribute to biological filtration, such as nitrifying bacteria, are usually aerobic, it is preferable that the filter media for biological filtration is made of a porous material such as ceramics or gravel, from the viewpoint of having a large surface area on which microorganisms can settle and allowing fluid to easily pass through. The filter device 30 is connected to the breeding tank 20 via a purified water passage 32, and the breeding water filtered by the filter device 30 is circulated to the breeding tank 20 via the purified water passage 32.

A three-way valve 34 and a solenoid valve 36 are provided in this order in the purified water passage 32 along the direction from the filtration device 30 to 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. The three-way valve 34 is also integrated with an electric pump 35, and the breeding water is circulated between the breeding tank 20 and the filtration device 30 by controlling the operation of the electric pump 35.

[Water quality management tank 40]
The water quality management tank 40 contains a filter medium 42 therein. The filter medium 42 is made of a porous material in which microorganisms that perform biological filtration can easily settle. The water quality management tank 40 is provided with a turbidity meter 44, which is configured to measure the turbidity of the rearing water stored in the water quality management tank 40. The turbidity meter 44 is electrically connected to the control device 80, and the timing of measurement is controlled. In addition, the measurement value by the turbidity meter 44, i.e., the turbidity of the rearing water, is transmitted from the turbidity meter 44 to the control device 80. In this disclosure, the water quality management tank 40 corresponds to a "container", and the turbidity meter 44 corresponds to a "turbidity measuring means".

The water quality control tank 40 is connected to a branch passage 46 that branches off from the purified water passage 32. The water quality control tank 40 is also connected to the breeding tank 20 via a return passage 48. As a result, a portion of the breeding water circulating within the breeding system 10 flows through the water quality control tank 40 via the branch passage 46 and the return passage 48.

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

[Microorganism addition device 60]
The microorganism addition device 60 is provided along the wastewater passage 22, and is configured so that the breeding water flows through the inside of the microorganism addition device 60. The microorganism addition device 60 stores microorganisms in a dormant state that perform biological filtration, and upon receiving a signal from the control device 80, adds the dormant microorganisms to the breeding water flowing inside. In this disclosure, the microorganism addition device 60 corresponds to the "water quality adjustment means."

[External water source 70]
The three-way valve 34 is connected to an external water source 70 via an introduction passage 38. The external water source 70 supplies tap water containing chlorine. The external water source 70 is not normally connected to the purified water passage 32, but when the control device 80 switches the three-way valve 34 to connect the external water source 70 to the purified water passage 32, tap water is introduced into the purified water passage 32. In this disclosure, the external water source 70 corresponds to a "sterilization means."

[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 of the electric devices of the rearing system 10, and controls each of the electric devices based on the control programs. In this disclosure, the control device 80 corresponds to the "water quality determination means."

<Water quality determination process>
Next, the water quality determination process in this embodiment will be described with reference to Fig. 1 to Fig. 3. Fig. 2 is a diagram showing the operating state of each electrically powered device during water quality determination and the change in turbidity in the water quality control tank 40. In Fig. 2, the turbidity when a sufficient amount of microorganisms is fixed on the filter medium 42 is shown by a solid line, and the turbidity when the amount of microorganisms is insufficient is shown by a dashed line. Fig. 3 is a diagram showing the relationship between the elapsed time after sterilization treatment and the measured turbidity.

The water quality assessment process is performed periodically, 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 communication with the external water source 70, the breeding water flows through the purified water 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 through the breeding system 10 via the breeding tank 20 and the filtration device 30, and a portion of the circulating breeding water flows into the water quality control tank 40 via the branch passage 46 and then returns to the breeding tank 20 via the return passage 48.

When the water quality determination process starts (T1), solenoid valves 50 and 52 are closed to prevent the breeding water from flowing into or out of 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 turbidity meter 44.

After measuring the turbidity of the breeding water (T2), the three-way valve 34 is switched to block the flow from upstream to downstream in the purified water passage 32 and to communicate between the external water source 70 and the downstream side of the purified water passage 32. In addition, the solenoid valve 36 is closed and the solenoid valve 50 is opened. This allows tap water to be supplied from the external water source 70 to the breeding system 10 and to flow into the water quality control tank 40 through the introduction passage 38, the purified water passage 32, and the branch passage 46. The filter medium 42 is then sterilized by the chlorine contained in the tap water, and the microorganisms that had been established on the filter medium 42 are killed. The killed microorganisms are released from the filter medium 42, and the turbidity of the breeding water in the water quality control tank 40 increases over time.

When a certain amount of tap water has flowed into the water quality management tank 40 (T3), the electric pump 35 is stopped. In this state, the turbidity of the rearing water in the water quality management tank 40 is measured by the turbidity meter 44 at regular intervals over a predetermined period of time.

When the turbidity measurement is completed (T4), the electric pump 35 is operated, and the three-way valve 34 is switched to cut off communication with the external water source 70, so that the rearing water flows from the upstream side to the downstream side in the purified water passage 32. In addition, the solenoid valve 56 is opened. This causes the rearing water to flow to the outside through the purified water passage 32, the branch passage 46, the water quality control tank 40, and the discharge passage 54, and liquid containing chlorine and dead microorganisms remaining in these passages and the water quality control tank 40 is discharged to the outside. When a certain amount of rearing water has been discharged to the outside (T5), the solenoid valves 36 and 52 are opened, and the solenoid valve 56 is closed, returning to the normal state.

Then, the control device 80 calculates the difference between the turbidity of the rearing water measured before the sterilization treatment (between T1 and T2) and the turbidity of the rearing water measured after the sterilization treatment (between T3 and T4). Note that the turbidity after the sterilization treatment usually increases over time because it increases according to the amount of dead microorganisms released from the filter medium 42. Therefore, as shown in FIG. 3, from the turbidities measured at regular intervals (T31 to T36), multiple turbidities (T35 and T36) whose deviations between each other are within a predetermined range are selected, and the average value is used as the turbidity after the sterilization treatment. Note that when multiple turbidities whose deviations between each other are within a predetermined range are used, they may be selected from multiple turbidities measured over time as described above, or may be selected from turbidities measured simultaneously at multiple locations in the water quality control tank 40.

The amount of change in turbidity before and after the sterilization process is mainly due to the amount of microorganisms killed or released by the sterilization process, so if the amount of change is equal to or greater than a predetermined value (see the solid line in Figure 2), the control device 80 determines that the amount of microorganisms adhering to the filter medium 42 is sufficient and the water quality is good. On the other hand, if the amount of change is less than the predetermined value (see the dashed line in Figure 2), the amount of microorganisms is insufficient and the water quality is determined to be poor.

When the breeding water is judged to have poor water quality, 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 transition from a dormant state to an active state, and settle on the filter media 31 in the filtration device 30 or the filter media 42 in the water quality control tank 40 as they circulate through the breeding system 10. This increases the amount of microorganisms in the breeding system 10, improving the water quality of the breeding water.

Advantages of the First Embodiment
According to the above embodiment, the water quality is determined based on the change in turbidity caused by the sterilization treatment of the filter medium 42, so that the water quality can be determined based on the amount of microorganisms that have settled on the filter medium 42.

In addition, since the turbidity after sterilization is calculated based on multiple turbidities whose deviations are within a specified range, it is less affected by turbidity variations caused by the flow of the breeding water in the water quality management tank 40, improving the accuracy of the determination.

In addition, if the water quality of the breeding water is judged to be poor, the microorganism addition device 60 adds dormant microorganisms to the breeding water, thereby increasing the amount of microorganisms that contribute to biological filtration. This makes it easy to improve the water quality.

<Embodiment 2>
Next, a second embodiment of the present disclosure will be described with reference to Figures 4 and 5. Since the second embodiment is a partial modification of the first embodiment, the same components are denoted by the same reference numerals and will not be described. Figure 4 is a schematic diagram showing a breeding system 110 according to the second embodiment, and the arrows in the figure indicate the flow direction of fluids in the breeding system 110.

[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, and although the number of filtration units is not particularly limited, it is preferable that the number is five or more (two filtration units 30A and 30B are shown in Fig. 4). The filtration units 30A and 30B are filled with a filter medium 31. In this disclosure, the filtration units 30A and 30B correspond to "containers."

The breeding tank 20 is connected to the filtration device 30 via a wastewater passage 122, along which a microorganism addition device 60 and an electric pump 35 are provided. The wastewater passage 122 branches into a first wastewater passage 122A and a second wastewater passage 122B between the microorganism addition device 60 and the filtration device 30, and is connected to the filtration units 30A and 30B, respectively. In addition, the first purified water passage 132A and the second purified water passage 132B extending from the filtration units 30A and 30B, respectively, join together to form the purified water passage 132, which is connected to the breeding tank 20. As a result, when the electric pump 35 is driven, the breeding water in the breeding tank 20 flows into one of the filtration units 30A, 30B via the wastewater passage 122, the first wastewater passage 122A, and the second wastewater passage 122B, where it is filtered, and then circulated to the breeding tank 20 via the first purified water passage 132A, the second purified water passage 132B, and the purified water passage 132.

A first branch passage 140A branches off from the first purified water passage 132A, and a three-way valve 142A is provided at the junction of the first purified water passage 132A and the first branch passage 140A. Similarly, a second branch passage 140B branches off from the second purified water passage 132B, and a three-way valve 142B is provided at the junction of the second purified water passage 132B and the second branch passage 140B. The first branch passage 140A and the second branch passage 140B join together to form the branch passage 140. A heater 144 and a turbidity meter 146 are provided on the branch passage 140.

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 wastewater passage 122A, and a three-way valve 150A is provided at the junction. The second return passage 148B is connected to the second wastewater passage 122B, and a three-way valve 150B is provided at the junction.

A discharge passage 152 and an introduction passage 154 are connected to the branch passage 140 downstream of the turbidity meter 146. A three-way valve 156 is installed at the junction of the discharge passage 152 and the branch passage 140. The other end of the discharge passage 152 is open to the outside, and is configured to be able to discharge the breeding water flowing through the branch passage 140 to the outside. On the other hand, a three-way valve 158 is provided at the junction of the introduction passage 154 and the branch passage 140. The other end of the introduction passage 154 is connected to a breeding water supply source 160, and new breeding water can be introduced from the outside into the breeding system 110 by connecting the introduction passage 154 and the branch passage 140. The three-way valves 142A, 142B, 150A, 150B, 156, and 158 are each electrically connected to the control device 80, and the communication direction is controlled. The three-way valve 158 also has an integrated electric pump 162, which is also driven and controlled by the control device 80.

[Heater 144]
The heater 144 is configured to heat the rearing water flowing therethrough based on a signal from the control device 80. The heated rearing water can be supplied to the filtration units 30A, 30B to sterilize the filter medium 31. Since microorganisms that contribute to biological filtration are killed by a sudden increase in temperature, it is preferable that the heater 144 is configured to increase the temperature of the rearing water by 15 to 20°C. In this disclosure, the heater 144 corresponds to the "sterilization means."

[Turbidity meter 146]
The turbidity meter 146 is configured to continuously or intermittently measure the turbidity of the rearing water flowing therethrough. The turbidity meter 146 is electrically connected to the control device 80, and after measuring the turbidity of the rearing water based on a signal from the control device 80, the turbidity meter 146 transmits the measurement result to the control device 80.

<Water quality determination process>
Next, the water quality determination process in this embodiment will be described with reference to Figures 4 and 5. Figure 5 is a diagram showing the operating state of each electrically-operated member during water quality determination and the change in turbidity of the rearing water flowing through the turbidimeter 146. In Figure 5, the turbidity when the amount of microorganisms settled on the filter medium 31 is sufficient is shown by a solid line, and the turbidity when the amount of microorganisms is insufficient is shown by a dashed line. Moreover, the direction of each three-way valve in Figure 5 means the communication direction of each three-way valve shown in Figure 4, more specifically, the flow direction of the rearing water.

The water quality assessment process is performed periodically, for example once a week. Furthermore, one filtration unit is the target of each water quality assessment process, and the multiple filtration units in the filtration device 30 are subject to the water quality assessment process in a predetermined order. Here, the water quality assessment process targeting filtration unit 30A will be described as an example.

As shown in FIG. 5, in the normal state (T0), the electric pump 162 is stopped, the three-way valves 142A and 150A are open in the left-right direction, and the three-way valves 156 and 158 are open in the right-left direction. Since the electric pump 35 is always running, the breeding water circulates between the breeding tank 20 and the filtration device 30 via the wastewater passage 122 and the purified water passage 132. In addition, since the communication between the branch passage 140 and the wastewater passage 122 and the purified water passage 132 is cut off, the breeding water circulating between the breeding tank 20 and the filtration device 30 does not flow into the branch passage 140.

When the water quality judgment process is started (T1), the three-way valve 150A is switched to communicate the first return passage 148A with the downstream side of the first wastewater passage 122A, and the three-way valve 142A is switched to communicate the upstream side of the first purified water passage 132A with the first branch passage 140A. In addition, 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 wastewater passage 122A, and is circulated by being returned to the heater 144 through the first purified water passage 132A and the first branch passage 140A. By the breeding water heated to a high temperature flowing into the filtration unit 30A, the filter medium 31 in the filtration unit 30A is sterilized, and the microorganisms that had settled on the filter medium 31 are killed and released. As a result, as the breeding water passes through the filtration unit 30A, the corpses of microorganisms are mixed into the breeding water, causing the turbidity of the breeding water to increase. The turbidity meter 146 continuously or intermittently measures the turbidity of the breeding water flowing therethrough for a predetermined period of time after the start of the water quality evaluation process. In this state, the breeding tank 20 and the filtration unit 30B are in communication with each other, and communication with the heater 144 is cut off, so that the heated breeding water is prevented from flowing into the breeding tank 20 or the filtration unit 30B, and circulation of the breeding water between the breeding tank 20 and the filtration unit 30B is maintained.

When a predetermined time has elapsed from the start of the water quality determination process (T2), the heater 144 is stopped, and the three-way valve 158 is switched to connect the inlet passage 154 to 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 to the discharge passage 152. As a result, rearing water at room temperature or a temperature suitable for the reared aquatic organisms is supplied from the rearing water supply source 160 through the inlet passage 154. The newly supplied rearing water is then discharged to the outside through the first return passage 148A, the first wastewater 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. As a result, the high-temperature rearing water and dead microorganisms remaining inside each passage and the filtration unit 30A can be discharged to the outside.

When a predetermined amount of rearing water has been 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 its initial state.

The control device 80 then calculates the amount of change between the turbidity of the rearing water measured at the start of the sterilization process (T1) and the turbidity of the rearing water measured after the sterilization process (the last measured value between T1 and T2). If the amount of change is equal to or greater than a predetermined value (see the solid line in Figure 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, if the amount of change is less than a predetermined value (see the dashed line in Figure 5), the amount of microorganisms is determined to be insufficient and the water quality is poor. Note that instead of the last measured turbidity, the turbidity after the sterilization process may be determined by selecting multiple turbidities whose deviations between them are within a predetermined range and using the average value as the turbidity after the sterilization process.

When the water quality of the breeding water is judged to be poor, the control device 80 operates the microorganism addition device 60 to add 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 media 31 in the filtration units 30A and 30B while circulating through the breeding system 110 including the breeding tank 20 and the filtration device 30. This increases the amount of microorganisms in the breeding system 110, improving the efficiency of biological filtration and improving the water quality of the breeding water.

Advantages of the Second Embodiment
According to the above embodiment, the water quality is judged based on the change in turbidity caused by the sterilization treatment of the filter medium 31, so that the water quality can be judged based on the amount of microorganisms that have settled on the filter medium 31 in the filtration device 30. In addition, since only one of the multiple filtration units is sterilized in one water quality judgment process, it is possible to minimize the deterioration of filtration performance caused by the sterilization treatment of the filter medium 31. In addition, during the water quality judgment process, the filtration units that are not the subject of the process are kept in communication with the breeding tank 20, and the electric pump 35 is also kept in a constantly operating state, so that the breeding water circulating between the breeding tank 20 and the filtration device 30 can be filtered even during the water quality judgment process.

In addition, since the sterilization process of the filter medium 31 is performed by heating with the heater 144, there is no need to introduce sterilizing components such as chlorine into the breeding system 110 for the sterilization process. This eliminates the possibility that microorganisms and aquatic organisms in the breeding tank 20 will be affected by sterilizing components remaining in the breeding system 110 after the water quality evaluation process.

[Other embodiments]
The technology disclosed in this specification is not limited to the above embodiment. For example, the sterilization treatment of the filter medium may be performed by changing the salinity concentration, rapidly cooling the breeding water, increasing the amount of dissolved carbon dioxide, electric shock, ultraviolet irradiation, etc., instead of introducing chlorine or heating the breeding water. For example, in the case of performing sterilization treatment by ultraviolet irradiation in the first embodiment, it is preferable to install a UV germicidal lamp capable of irradiating ultraviolet rays of a predetermined wavelength in the water quality management tank 40, and use transparent ceramic that transmits ultraviolet rays as the filter medium 42. In this case, the UV germicidal lamp and the turbidity meter 44 use the same light source, thereby simplifying the device.

In addition, in the above embodiment, the amount of change in turbidity before and after the sterilization process was compared with a predetermined value in the water quality determination process, but the turbidity after the sterilization process may also be compared with a predetermined value. This can simplify the water quality determination process and shorten the processing time.

In addition, in the above embodiment, microorganisms are added to the breeding water when the amount of change in turbidity before and after the sterilization treatment is less than a predetermined value, but the amount of change may be compared with a number of predetermined values, and the amount of microorganisms added may be adjusted according to the amount of change in turbidity. This allows an appropriate amount of microorganisms to be added according to the amount of microorganisms established on the filter medium.

In addition, the method of adjusting the water quality is not limited to adding microorganisms, but may be performed by adjusting pH, salinity, temperature, dissolved oxygen concentration, etc., or these may be used in combination with adding microorganisms. Since the number of microorganisms in the breeding system decreases due to various factors, devices for measuring and adjusting pH, etc. may be installed, and if the water quality is determined to be poor, the factors inhibiting the growth of microorganisms may be identified and improved.

10, 110 Breeding system 20 Breeding tank 30 Filtration device 30A, B Filtration unit (container)
31, 42 Filter medium 40 Water quality control tank (container)
44,146 Turbidity meter (turbidity measurement 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 (4)

A water quality testing device for a breeding system including a breeding tank,
A container connected to the breeding tank and through which breeding water containing microorganisms for biological filtration circulating within the breeding system flows;
A filter medium contained in the container;
a sterilization means for sterilizing the filter medium to kill the microorganisms ;
A turbidity measuring means for measuring the turbidity of at least one of the breeding water containing the dead microorganisms in the container and the breeding water containing the dead microorganisms that has passed through the container after the sterilization means has sterilized the filter medium;
a water quality determining means for determining that the water quality of the breeding water in the breeding tank is better as the turbidity is greater;
A water quality testing device comprising: The water quality testing device according to claim 1,
The sterilization means sterilizes the filter medium by ultraviolet light of a predetermined wavelength,
A water quality testing device, wherein the sterilization means and the turbidity measurement means use the same light source. The water quality testing device according to claim 1 or 2,
A water quality testing device, wherein the water quality is determined by the water quality determining means based on a plurality of turbidities whose deviations from one another are within a predetermined range. A breeding system comprising the water quality testing device according to claim 1 or 2,
A breeding system comprising a water quality adjusting means for adjusting the water quality of the breeding water based on the result of the judgment by the water quality judgment means.

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