Water treatment apparatus

Abstract

To provide reduction of the number of parts required to detect water level and water quality compared to the case where detection means to detect water level and detection means to detect water quality are provided separately.SOLUTION: A water treatment apparatus includes a storage tank in which treated water containing impurities or water to be treated is stored, a plurality of electrodes located inside the storage tank and spaced vertically apart, and a control unit that detects the water level in the storage tank by energizing one electrode and the other electrodes through the water in the storage tank, and detects water quality by the energized current value.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a water treatment device. [Background technology]

[0002] In the boiler feedwater method described in Patent Document 1, condensate and soft water are mixed in a boiler feedwater tank to prepare boiler feedwater, which is then supplied to the boiler. The electrical conductivity or resistivity of the boiler feedwater is measured, and when the electrical conductivity falls below a first set value or the resistivity rises to a first predetermined value or more, part of the water in the boiler feedwater tank is discharged, and then soft water is supplied to the boiler feedwater tank. [Patent Document 1] JP 2021-143812 A Summary of the Invention [Problem to be solved by the invention]

[0003] Conventionally, a plurality of electrodes are arranged vertically spaced apart inside a storage tank in which water is stored, and the water level of the storage tank is detected by the electrical conductivity between one electrode and another electrode. Also, a detection means for detecting the water quality of the water stored in the storage tank is provided separately from the electrodes for detecting the water level.

[0004] An object of the present disclosure is to reduce the number of parts required to detect the water level and water quality, compared to a case in which a detection means for detecting the water quality is provided separately from an electrode for detecting the water level. [Means for solving the problem]

[0005] The water treatment device of the first aspect of the present disclosure is characterized in that it comprises a storage tank in which treated water or water to be treated containing impurities is stored, a plurality of electrodes arranged inside the storage tank and spaced apart in the vertical direction, and a detection unit that detects the water level of the storage tank by passing electricity between one of the electrodes and the other of the electrodes via the treated water from the storage tank, and detects the water quality based on the value of the current flowing between the one of the electrodes and the other of the electrodes.

[0006] According to the above aspect, the number of parts required to detect the water level and the water quality can be reduced compared to a case in which a detection means for detecting the water level and a detection means for detecting the water quality are provided separately.

[0007] The water treatment device of the second aspect of the present disclosure is characterized in that, in the water treatment device of the first aspect, it further comprises a discharge unit that discharges the treated water in the storage tank out of the system when the value of the current flowing between one of the electrodes and the other of the electrodes becomes equal to or greater than a threshold value. The threshold value has a numerical range of 500 μS / cm to 10,000 μS / cm, preferably 1,000 μS / cm to 5,000 μS / cm.

[0008] A third aspect of the water treatment device of the present disclosure is characterized in that, in the water treatment device of the third aspect, the discharge section stops discharging the treated water when the current value flowing between one of the electrodes and the other of the electrodes becomes less than another threshold value that is lower than the one threshold value while the treated water in the storage tank is being discharged outside the system.

[0009] According to the above aspect, it is possible to prevent treated water that meets certain water quality standards from being discharged outside the system, compared to when treated water whose current value is below another threshold value is discharged outside the system.

[0010] A water treatment device of a fourth aspect of the present disclosure is characterized in that, in the water treatment device described in any one of the first to third aspects, it comprises a biological treatment tank provided upstream of the storage tank in the flow direction of the treated water, and a reverse osmosis membrane provided downstream of the storage tank in the flow direction, through which the treated water passes and separates it into permeate and concentrated water.

[0011] A water treatment device of a fifth aspect of the present disclosure is characterized in that, in the water treatment device of the first aspect, it comprises a reverse osmosis membrane that is provided downstream of the storage tank in the flow direction of the treated water, and which passes the treated water through to separate it into permeate and concentrated water, and a cleaning section that, when the value of the current flowing between one of the electrodes and the other of the electrodes becomes equal to or greater than a wastewater threshold value, passes the permeate that has permeated the reverse osmosis membrane through the reverse osmosis membrane to clean the reverse osmosis membrane.

[0012] According to the above aspect, the reverse osmosis membrane can be cleaned more effectively than when the reverse osmosis membrane is cleaned at set time intervals. Effect of the Invention

[0013] According to the present disclosure, the number of parts required to detect water level and water quality can be reduced compared to when a detection means for detecting water quality is provided separately from an electrode for detecting water level. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic configuration diagram showing a water treatment device according to a first embodiment of the present disclosure. [Diagram 2] 3 is a configuration diagram showing an intermediate tank, a reverse osmosis membrane, and the like provided in a second housing in the water treatment device according to the first embodiment of the present disclosure. FIG. [Diagram 3] 3A and 3B are block diagrams showing the hardware configuration and functional configuration of a control unit in a water treatment device according to a first embodiment of the present disclosure. [Figure 4] FIG. 4 is a flow diagram showing a water treatment flow by a control unit in the water treatment device according to the first embodiment of the present disclosure. [Diagram 5] 13A and 13B are block diagrams showing the hardware configuration and functional configuration of a control unit in a water treatment device according to a second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] First Embodiment An example of a water treatment device according to a first embodiment of the present disclosure will be described with reference to Figures 1 to 4. Note that, in the figures, arrow H indicates the up-down direction (vertical direction) of the device, arrow W indicates the width direction (horizontal direction) of the device, and arrow D indicates the depth direction (horizontal direction) of the device.

[0016] The water treatment device 1012 is a device that purifies water to be treated that has been used in the home while circulating it, for example, so that the water can be reused within the home. First, a schematic configuration of the water treatment device 1012 will be described.

[0017] (Schematic configuration of water treatment device 1012) As shown in FIG. 1, the water treatment device 1012 is provided with a wastewater tank 1100, a biological treatment tank 1300, a first treatment water tank 1400, an intermediate tank 1500, a reverse osmosis membrane 1600, and a second treatment water tank 1700.

[0018] The treated water used within the home passes through a drainage tank 1100, a biological treatment tank 1300, a first treatment tank 1400, an intermediate tank 1500, a reverse osmosis membrane 1600, and a second treatment tank 1700 in that order, before being circulated to a water usage point 1014 (such as a washroom, a bath, or a toilet seat with a flushing function).

[0019] [Drain tank 1100] The drainage tank 1100 is connected to the water usage point 1014 via a first drainage pipe 1102. Then, the water to be treated from the water usage point 1014 is sent to the drainage tank 1100 via the first drainage pipe 1102.

[0020] In addition, the water treatment device 1012 is equipped with a second drainage pipe 1302 that connects the drainage tank 1100 and the biological treatment tank 1300, and the treated water from the drainage tank 1100 is sent to the biological treatment tank 1300 through the second drainage pipe 1302 by a driven pump (not shown).

[0021] [Biological treatment tank 1300] The biological treatment tank 1300 is a treatment tank that performs biological treatment on the water to be treated, and as shown in Fig. 1, is connected to a first treated water tank 1400 via a first treated water pipe 1402. A treated water pump 1406 is provided in the first treated water pipe 1402. A filtration membrane (not shown) is further provided inside the biological treatment tank 1300.

[0022] As a result, the driven treated water pump 1406 passes the water to be treated through the filtration membrane. At this time, foreign matter is removed from the water to be treated. Furthermore, the water from which the foreign matter has been removed is sent as treated water to the first treated water tank 1400 through the first treated water piping 1402.

[0023] [First treatment tank 1400] The first treatment water tank 1400 is connected to an intermediate tank 1500 by an intermediate pipe 1502. An intermediate pump 1504 is provided in the intermediate pipe 1502. Thus, when the intermediate pump 1504 is driven, the treated water from the first treatment water tank 1400 is sent to the intermediate tank 1500 through the intermediate pipe 1502.

[0024] [Intermediate tank 1500, reverse osmosis membrane 1600] The intermediate tank 1500 is connected to the second treated water tank 1700 by a second treated water piping 1702 via a reverse osmosis membrane 1600. Specifically, the second treated water piping 1702 is provided with a treated water pump 1710 and the reverse osmosis membrane 1600 from the intermediate tank 1500 side.

[0025] As a result, the driven treated water pump 1710 sends the treated water in the intermediate tank 1500 to the reverse osmosis membrane 1600, and foreign matter is removed from the treated water. The treated water from which the foreign matter has been removed (permeated water) is sent to the second treated water tank 1700 through a second treated water piping 1702. Furthermore, the reverse osmosis membrane 1600 produces concentrated water with a high concentration of foreign matter. A concentrated water piping 1602 is provided to connect the reverse osmosis membrane 1600 and the intermediate tank 1500, and the concentrated water is returned to the intermediate tank 1500 through the concentrated water piping 1602.

[0026] [Second treatment tank 1700] The second treatment water tank 1700 is connected to the intermediate tank 1500 by a return pipe 1706. A return pump 1708 is provided in the return pipe 1706. Thus, when the return pump 1708 is driven, the treated water in the second treatment water tank 1700 is sent to the intermediate tank 1500 through the return pipe 1706.

[0027] The second treatment water tank 1700 is connected to the water usage points 1014 by a supply pipe 1716. A supply pump 1724 is provided on the supply pipe 1716. This allows the treated water from the second treatment water tank 1700 to each of the water usage points 1014 through the supply pipe 1716 by the driven supply pump 1724. Note that in practice, the supply pipe 1716 branches out toward each of the water usage points 1014.

[0028] (Main components of the water treatment device 1012) Next, the intermediate tank 1500 and the control unit 1060 will be described.

[0029] [Intermediate tank 1500] 2, a first electrode 1512, a second electrode 1514, and a third electrode 1516 are provided inside the intermediate tank 1500, which are suspended from a ceiling portion 1500a of the intermediate tank 1500. The intermediate tank 1500 is an example of a storage tank.

[0030] In the vertical direction of the device, the first electrode 1512 is disposed in a lower portion of the intermediate tank 1500, the second electrode 1514 is disposed in a central portion of the intermediate tank 1500, and the third electrode 1516 is disposed in an upper portion of the intermediate tank 1500.

[0031] Furthermore, a discharge pipe 1522 is provided for discharging the treated water from the intermediate tank 1500 to the outside, and one end of the discharge pipe 1522 faces the bottom of the intermediate tank 1500. Also, a discharge pump 1524 is provided on the discharge pipe 1522. As a result, when the discharge pump 1524 is driven, the treated water of the intermediate tank 1500 is discharged to the outside through the discharge pipe 1522.

[0032] The water treatment device 1012 also has a measuring unit 1520 (see Figure 3 (A)) that measures the value of the current flowing between the first electrode 1512 and the second electrode 1514, and the value of the current flowing between the first electrode 1512 and the third electrode 1516.

[0033] [Control unit 1060] -Hardware configuration of the control unit 1060- 3A, the control unit 1060 includes a CPU (Central Processing Unit) 1061, a ROM (Read Only Memory) 1062, a RAM (Random Access Memory) 1063, a storage 1064, and a communication interface (I / F) 1065. Each component is connected to each other via a bus 1069 so as to be able to communicate with each other.

[0034] The CPU 1061 is a central processing unit that executes various programs and controls each part. That is, the CPU 1061 reads a program from the ROM 1062 or the storage 1064, and executes the program using the RAM 1063 as a working area. The CPU 1061 controls each component and performs various calculation processes according to the program stored in the ROM 1062 or the storage 1064.

[0035] In this embodiment, for example, the ROM 1062 or the storage 1064 stores a driving program for driving each unit in response to detection results from the first electrode 1512, the second electrode 1514, the third electrode 1516, and the measuring unit 1520.

[0036] The RAM 1063 temporarily stores programs or data as a working area. The storage 1064 is configured with a hard disk drive (HDD) or a solid state drive (SSD), and stores various programs including an operating system, and various data.

[0037] The communication interface 1065 is an interface for the control unit 1060 to communicate with the first electrode 1512, the second electrode 1514, the third electrode 1516, the discharge pump 1524, the return pump 1708, the treated water pump 1710, and the measuring unit 1520, and uses standards such as Ethernet (registered trademark), FDDI, and Wi-Fi (registered trademark), for example.

[0038] When executing the above operating program, the control unit 1060 realizes various functions using the above hardware resources. The functional configuration of the control unit 1060 that realizes the various functions will be described below.

[0039] -Functional configuration of the control unit 1060- 3B, the control unit 1060 has a receiving unit 1072, a detection unit 1074, and a driving unit 1076. Each functional configuration is realized by the CPU 1061 reading and executing a driving program stored in the ROM 1062 or the storage 1064. The driving unit 1076 is an example of a discharge unit.

[0040] (action) Next, the operation of the receiving unit 1072 of the control unit 1060 to drive each unit upon receiving the detection results of the first electrode 1512, the second electrode 1514, the third electrode 1516, and the measuring unit 1520 will be described with reference to the flow diagram of Fig. 4. Specifically, a voltage is applied to each electrode, and the measuring unit 1520 measures the value of the current flowing between the first electrode 1512 and the second electrode 1514 and the value of the current flowing between the first electrode 1512 and the third electrode 1516 via the treatment water stored in the intermediate tank 1500, and the operation of driving each unit will be described with reference to the flow diagram of Fig. 4.

[0041] 2 is driven, and the treated water is sent to the intermediate tank 1500 through the intermediate piping 1502. When the treated water sent to the intermediate tank 1500 is stored therein and the liquid level of the treated water reaches the second electrode 1514, in step S100, the receiving unit 1072 receives the value of the current flowing between the first electrode 1512 and the second electrode 1514 from the measuring unit 1520. The intermediate pump 1504 is driven and stopped as appropriate based on the water level in the first treated water tank 1400, etc.

[0042] Furthermore, in step S200, the detection unit 1074 detects the water level of the intermediate tank 1500 by energizing the first electrode 1512 and the second electrode 1514, and detects the water quality of the treated water by the current value received by the receiving unit 1072. In other words, the detection unit 1074 detects the water quality of the treated water by the electrical conductivity of the treated water. When the treated water contains a large amount of impurities, the current flows easily and the current value becomes large. On the other hand, when the treated water contains a small amount of impurities, the current flows less easily and the current value becomes small. Therefore, the detection unit 1074 determines whether the current value received by the receiving unit 1072 is equal to or greater than a first threshold value. When the current value is equal to or greater than the first threshold value, the detection unit 1074 detects that the water quality of the treated water is low.

[0043] If the current value is equal to or greater than the first threshold, the process proceeds to step S300, and if the current value is less than the first threshold, the process proceeds to step S310. The first threshold is an example of one threshold.

[0044] In step S300, the driving unit 1076 drives the discharge pump 1524 to discharge the treated water in the intermediate tank 1500 outside the system through the discharge pipe 1522. Specifically, this discharged treated water is temporarily stored in a storage tank (not shown) and used as toilet water. Then, after discharging the treated water in the intermediate tank 1500 outside the system, the driving unit 1076 stops the discharge pump 1524. When the discharge pump 1524 stops, the process returns to step S100 again, and the receiving unit 1072 receives the value of the current flowing between the first electrode 1512 and the second electrode 1514 from the measuring unit 1520.

[0045] On the other hand, in step S200, when the current value is less than the first threshold value and the process proceeds to step S310, and the liquid level of the treated water sent to the intermediate tank 1500 reaches the third electrode 1516, the receiving unit 1072 receives the value of the current flowing between the first electrode 1512 and the third electrode 1516 from the measuring unit 1520.

[0046] Furthermore, in step S410, the detection unit 1074 detects the water level of the intermediate tank 1500 by energizing the first electrode 1512 and the third electrode 1516, and detects the water quality of the treated water from the current value received by the receiving unit 1072. Specifically, the detection unit 1074 determines whether the current value received by the receiving unit 1072 is equal to or greater than a first threshold value. If the current value is equal to or greater than the first threshold value, the detection unit 1074 detects that the water quality of the treated water is low.

[0047] If the current value is equal to or greater than the first threshold value, the process proceeds to step S510, and if the current value is less than the first threshold value, the process proceeds to step S520.

[0048] In step S510, the drive unit 1076 drives the discharge pump 1524 to discharge the treated water in the intermediate tank 1500 to the outside of the system through the discharge pipe 1522. When the treated water in the intermediate tank 1500 becomes the water to be treated and the liquid level in the intermediate tank 1500 moves away from the third electrode 1516, the process proceeds to step S610.

[0049] In step S610, the receiving unit 1072 receives the value of the current flowing between the first electrode 1512 and the second electrode 1514 from the measuring unit 1520, and the detecting unit 1074 judges whether the current value received by the receiving unit 1072 is equal to or greater than the second threshold value. If the current value is equal to or greater than the second threshold value, the process proceeds to step S710, and if the current value is less than the second threshold value, the process proceeds to step S720. The reason why the current value may decrease is that impurities are often present in the lower part of the intermediate tank 1500, and the treated water in the lower part of the intermediate tank 1500 is sequentially discharged out of the system by the discharge pipe 1522. The second threshold value is an example of another threshold value, and is a value lower than the first threshold value.

[0050] In step S710, the driving unit 1076 continues the discharge operation of the treated water, and discharges the treated water in the intermediate tank 1500 to the outside of the system through the discharge pipe 1522. Specifically, this discharged treated water is temporarily stored in a storage tank (not shown) and used as toilet water. Then, after discharging the treated water in the intermediate tank 1500 to the outside of the system, the driving unit 1076 stops the discharge pump 1524. When the discharge pump 1524 stops, the process returns to step S100 again, and the receiving unit 1072 receives the value of the current flowing between the first electrode 1512 and the second electrode 1514 from the measuring unit 1520.

[0051] On the other hand, if the current value is less than the second threshold in step S610 and the process proceeds to step S720, the driving unit 1076 stops the discharge operation of the treated water, and the process returns to step S310 and the above-mentioned operation is repeated again.

[0052] Furthermore, in step S410, if the current value is less than the first threshold and the process proceeds to step S520, the driving unit 1076 drives the treated water pump 1710, and the driven treated water pump 1710 sends the treated water in the intermediate tank 1500 to the reverse osmosis membrane 1600, and foreign matter is removed from the treated water. When a predetermined time has elapsed since the treated water pump 1710 was driven, the process proceeds to step S620.

[0053] In S620, the driving unit 1076 stops the treated water pump 1710. Then, the process returns to step S100, and the above-described operations are repeated.

[0054] (summary) As described above, in water treatment device 1012, receiving unit 1072 receives the current value between first electrode 1512 and second electrode 1514, or the current value between first electrode 1512 and third electrode 1516 from measuring unit 1520. Furthermore, detection unit 1074 detects the water level in intermediate tank 1500 and detects the water quality from the current value. This makes it possible to reduce the number of parts required to detect the water level and water quality, compared to a case in which a detection means for detecting the water level and a detection means for detecting the water quality are provided separately.

[0055] Furthermore, in water treatment device 1012, when the detected water quality reaches the first threshold value, drive unit 1076 drives discharge pump 1524 to discharge the treated water in intermediate tank 1500 outside the system through discharge piping 1522. This makes it possible to effectively discharge treated water of reduced quality outside the system, compared to a case in which the treated water from the intermediate tank is discharged assuming that the quality of the treated water stored in a location other than the intermediate tank is the same as the quality of the treated water from the intermediate tank.

[0056] In addition, in water treatment device 1012, when the current value becomes less than the second threshold value while the treated water in intermediate tank 1500 is being discharged outside the system, drive unit 1076 stops driving discharge pump 1524 and stops discharging the treated water. This makes it possible to prevent treated water that meets a certain water quality standard from being discharged outside the system.

[0057] <Second embodiment> An example of a water treatment device according to a second embodiment of the present disclosure will be described with reference to Fig. 5. The second embodiment will be described mainly with respect to differences from the first embodiment. A water treatment device 2012 according to the second embodiment includes a control unit 2060.

[0058] [Control unit 2060] -Hardware configuration of the control unit 2060- 5(A), the control unit 2060 includes a CPU (Central Processing Unit) 2061, a ROM (Read Only Memory) 2062, a RAM (Random Access Memory) 2063, a storage 2064, and a communication interface (I / F) 2065. Each component is connected to each other via a bus 2069 so as to be able to communicate with each other.

[0059] The communication interface 2065 is an interface for the control unit 2060 to communicate with the first electrode 1512, the second electrode 1514, the third electrode 1516, the reflux pump 1708, the treated water pump 1710, and the measuring unit 1520, and uses standards such as Ethernet (registered trademark), FDDI, and Wi-Fi (registered trademark), for example.

[0060] When executing the above operating program, the control unit 2060 realizes various functions using the above hardware resources. The functional configuration of the control unit 2060 that realizes the various functions will be described below.

[0061] -Functional configuration of the control unit 2060- 5(B), the control unit 2060 has a receiving unit 2072, a detection unit 2074, and a driving unit 2076. Each functional configuration is realized by the CPU 2061 reading and executing a driving program stored in the ROM 2062 or the storage 2064. The driving unit 2076 is an example of a cleaning unit.

[0062] (action) The receiving unit 2072 receives the current value from the measuring unit 1520. Then, when the detecting unit 2074 detects that the value of the current flowing between the first electrode 1512 and the second electrode 1514 or the value of the current flowing between the first electrode 1512 and the third electrode 1516 shown in FIG. 2 is equal to or greater than a predetermined threshold value for discharge to the outside of the system, the reflux pump 1708 is driven to supply the treated water (permeated water) that has permeated the reverse osmosis membrane 1600 to the intermediate tank 1500.

[0063] 2 and opens a needle valve (not shown) provided in the concentrated water pipe 1602. As a result, the treated water is circulated between the reverse osmosis membrane 1600 and the intermediate tank 1500, thereby cleaning (flushing) the reverse osmosis membrane of the reverse osmosis membrane 1600 with the permeated water. In this way, clogging of the reverse osmosis membrane caused by passing treated water of low water quality through the reverse osmosis membrane is suppressed. When cleaning of the reverse osmosis membrane 1600 is completed, the drive unit 2076 stops driving each unit and throttles a needle valve (not shown) provided in the concentrated water pipe 1602.

[0064] (summary) As described above, when the quality of treated water in the intermediate tank 1500 becomes equal to or higher than a predetermined threshold for discharge outside the system, the water treatment device 2012 cleans (flushes) the reverse osmosis membrane of the reverse osmosis membrane 1600. Therefore, the reverse osmosis membrane 1600 can be cleaned more effectively than when the reverse osmosis membrane is cleaned at set time intervals, for example.

[0065] Although the present disclosure has been described in detail with respect to a specific embodiment, it is clear to those skilled in the art that the present disclosure is not limited to the embodiment, and various other embodiments are possible within the scope of the present disclosure. For example, in the above embodiment, the water treatment device 1012 is a device that purifies the water to be treated used in the home while circulating it, and makes it reusable in the home, but by reducing the number of drainage tanks and treatment tanks and reducing the purification process, the water treatment device may be used for water to be treated used in a toilet, rather than water to be treated used in the home.

[0066] Furthermore, in the above embodiment, the number of electrodes is three, but any number may be used, and the number may be two, or four or more.

[0067] In addition, in the above embodiment, no current is applied between the second electrode 1514 and the third electrode 1516, but current may be applied between the second electrode 1514 and the third electrode 1516. Then, the water quality in the portion between the second electrode 1514 and the third electrode 1516 may be determined.

[0068] In addition, in the above embodiment, the intermediate tank 1500 is provided between the biological treatment tank 1300 and the reverse osmosis membrane 1600 in the flow direction of the treated water, but the intermediate tank 1500 may be disposed at another position. In this case, however, the effect of providing the intermediate tank 1500 between the biological treatment tank 1300 and the reverse osmosis membrane 1600 is not achieved.

[0069] In addition, in the above first embodiment, when the current value is less than the second threshold value, the discharge operation of the treated water is stopped in step S720, but the treated water in the intermediate tank 1500 may be entirely discharged without stopping the discharge operation of the treated water. However, in this case, the effect achieved by stopping the discharge operation of the treated water is not achieved.

[0070] In addition, in the above embodiment, the water contained in the wastewater tank 1100 and the biological treatment tank 1300 is referred to as the water to be treated, the water contained in the first treatment water tank 1400 and the intermediate tank 1500 is referred to as the treated water, and the water contained in the second treatment water tank 1700 is referred to as the regenerated water. [Explanation of symbols]

[0071] 1012 Water treatment equipment 1074 Detector 1076 Drive unit (an example of the discharge unit) 1300 Biological treatment tank 1500 Intermediate tank (an example of a storage tank) 1512 First electrode (an example of an electrode) 1514 Second electrode (an example of an electrode) 1516 Third electrode (an example of an electrode) 1600 Reverse Osmosis Membrane 2012 Water treatment equipment 2074 Detector 2076 Drive unit (example of cleaning unit)

Claims

1. A storage tank for storing treated water or water to be treated that contains impurities; A plurality of electrodes disposed within the reservoir and spaced apart in a vertical direction; a detection unit that detects the water level of the storage tank by passing a current between the one electrode and the other electrode via the treated water in the storage tank, and detects the water quality based on the value of a current flowing between the one electrode and the other electrode; A water treatment device comprising:

2. and a discharge unit that discharges the treated water in the storage tank out of the system when a current value flowing between one of the electrodes and the other electrode becomes equal to or greater than a threshold value. The water treatment device according to claim 1 .

3. When a current value flowing between one of the electrodes and the other of the electrodes becomes less than another threshold value that is lower than the first threshold value while the treated water in the storage tank is being discharged outside the system, the discharge unit stops discharging the treated water. The water treatment device according to claim 2 .

4. A biological treatment tank provided upstream of the storage tank in the flow direction of the treated water; A reverse osmosis membrane is provided downstream of the storage tank in the flow direction, and passes the treated water through the reverse osmosis membrane to separate the treated water into a permeate and a concentrated water. The water treatment device according to claim 1 .

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