Water quality control method and water quality control device

Abstract

To provide a water quality control method and a water quality control device which, in water treatment of water to be treated including a control object ion and a removal object ion, can remove the removal object ion at a high removal efficiency without increase in size compared with the conventional ones.SOLUTION: A water quality control method of water to be treated including a control object ion and a removal object ion includes bringing the water to be treated into contact with an ion exchanger which absorbs and desorbs the control object ion and then removing the removal object ion from the water to be treated.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a water quality control method and a water quality control device, and more particularly to a water quality control method and a water quality control device for removing target elements such as heavy metal elements, amphoteric elements, and radioactive elements from wastewater. [Background technology]

[0002] As an example of a water treatment method that can stably treat water containing relatively high concentrations of fluoride ions using a fluorine adsorbent, Patent Document 1 describes an adsorption step in which water containing fluoride ions and sulfate ions is introduced into an adsorption tower filled with a fluorine adsorbent to obtain treated water from which at least a portion of the fluoride ions in the water is removed, and a return step in which a portion of the treated water is added to the water before the adsorption tower, wherein the sulfate ion concentration of the water introduced into the adsorption tower is 8,000 mg / L or higher. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-198826 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Industrially important but hazardous heavy metals, such as arsenic in semiconductors and mercury in fluorescent lamps, need to be recovered when disposing of waste containing them. One recovery method is adsorption treatment. This method involves bringing the waste liquid generated when waste is treated with acid or other substances into contact with an adsorbent, thereby selectively adsorbing heavy metals onto the adsorbent and recovering them. An example of such technology is the technology described in Patent Document 1 mentioned above.

[0005] The type of adsorbent used varies depending on the heavy metal to be recovered. For example, arsenic is known to be adsorbed by cerium hydroxide or dolomite, with cerium hydroxide showing good adsorption performance at pH 7 to pH 9 and dolomite at pH 10 to pH 12. Mercury is known to be adsorbed by chelate resins or activated carbon, with chelate resins showing good adsorption performance at pH 5 to pH 7 and activated carbon at pH 2 to pH 4.

[0006] Given the characteristics of the adsorption process described above, in heavy metal recovery processes, it is desirable to control the pH of the water to be treated during the adsorption process within a certain range in order to maintain the performance of the adsorption process.

[0007] However, the properties of wastewater are not constant in waste treatment processes. For example, even when recovering arsenic from the same semiconductor waste, the characteristics of the waste differ depending on the semiconductor manufacturer and type. In addition, the other waste materials mixed in also differ each time. As a result, the pH and composition of the resulting wastewater fluctuate and are not constant.

[0008] Therefore, in order to adjust the pH of the water to be treated before the adsorption process, it is conceivable to temporarily store the generated wastewater in a buffer tank, adjust the pH of the wastewater in the buffer tank, and then send it to the adsorption process as the water to be treated. In this case, the water to be treated cannot be sent to the adsorption process until the pH adjustment of the wastewater is complete, and the adsorption process will be stopped, resulting in intermittent treatment.

[0009] To shorten the aforementioned downtime, one method is to increase the capacity of the buffer tank and thus increase the amount of wastewater whose pH is adjusted at one time. This makes it possible to relatively shorten the downtime of the adsorption treatment within the total period of intermittent treatment. However, increasing the capacity of the buffer tank presents the challenge of increasing the size of the water treatment facility accordingly.

[0010] The object of the present invention is to provide a water quality control method and a water quality control device that can remove ions to be removed with high removal efficiency without increasing the size compared to conventional methods, in water treatment of water containing ions to be controlled and ions to be removed. [Means for solving the problem]

[0011] The present invention includes several means for solving the above problems, but one example is: Contains protons Controlled ions and Contains radioactive elements A method for controlling the water quality of treated water containing ions to be removed, stomach The water to be treated is brought into contact with an ion exchanger that adsorbs and desorbs ON, The control target ions containing the protons are exchanged with the ions held in the ion exchanger, and it is determined whether the concentration or activity of the control target ions containing the protons in the treated water after contact with the ion exchanger is within a predetermined range of concentration or activity. If, as a result of the determination, the concentration or activity of the control target ions containing the protons is outside the predetermined range of concentration or activity, the control target ions containing the protons or their activity are adjusted before ion exchange by the ion exchanger. Note After contact with the ion exchanger From the water to be treated, the above Contains radioactive elements It is characterized by removing the target ions. [Effects of the Invention]

[0012] According to the present invention, in water treatment of water containing ions to be controlled and ions to be removed, the ions to be removed can be removed with high removal efficiency without increasing the size compared to conventional methods. Other problems, configurations, and effects will be clarified by the following description of the examples. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic diagram showing the water quality control device of Example 1. [Figure 2] This figure shows an overview of the phenomena that occur when pH is controlled using the ion exchanger in the water quality control device of Example 1. [Figure 3] This graph shows the time-dependent change in pH at the inlet and outlet of a container filled with the ion exchanger to be controlled in the water quality control device of Example 1. [Figure 4] This is a schematic diagram showing the water quality control device of Example 2. [Figure 5] This is a flowchart showing the water treatment procedure using the water quality control device in Example 2. [Figure 6] It is a graph showing the change over time of pH at the inlet and outlet of a container filled with a controlled ion exchanger when Example 2 is applied. [Figure 7] It is a schematic configuration diagram showing a specific example 1 of the water quality control device of Example 2. [Figure 8] It is a schematic configuration diagram showing a specific example 2 of the water quality control device of Example 2. [Figure 9] It is a schematic configuration diagram showing the water quality control device of Example 3.

Mode for Carrying Out the Invention

[0014] Examples of the water quality control method and water quality control device of the present invention will be described below with reference to the drawings. In the drawings used in this specification, the same or corresponding components are denoted by the same or similar reference numerals, and repeated descriptions of these components may be omitted.

[0015] Also, the following examples are presented as examples and do not limit the scope of the present invention. These examples can be added, omitted, replaced, changed, etc. without departing from the gist of the present invention.

[0016] <Example 1> Examples 1 of the water quality control method and water quality control device of the present invention will be described with reference to FIGS. 1 to 3.

[0017] First, the overall configuration of the water quality control device will be described with reference to FIG. 1. FIG. 1 is a diagram showing an overview of the water quality control device 1.

[0018] The water quality control device 1 shown in FIG. 1 is a device for controlling the water quality of the treated water containing the controlled ions and the ions to be removed, and includes a controlled ion exchanger storage container 4 for storing an ion exchanger that adsorbs and desorbs the controlled ions, and a removal target ion removal device 6 that is disposed on the downstream side of the controlled ion exchanger storage container 4 and removes the removal target ions.

[0019] With such a water quality control device 1, preferably, the water to be treated is brought into contact with an ion exchanger that adsorbs and desorbs ions to be controlled, and then the water to be treated is removed from the water to be treated. This is the water quality control method of the water to be treated that includes the ions to be controlled and the ions to be removed in this embodiment.

[0020] As shown in Figure 1, the water to be treated is supplied from the water to be treated supply device 2 through piping 3 to the ion exchange container 4. In the ion exchange container 4, the water to be treated comes into contact with the ion exchange. After contact with the ion exchange, the water to be treated flows through piping 5 into the ion removal device 6 installed downstream. In the ion removal device 6, the ions to be removed are removed from the water to be treated.

[0021] Furthermore, the controlled ions adsorbed and desorbed in the controlled ion exchanger storage container 4 and the removed ions removed by the ion removal device 6 are not limited to one type each, but can be multiple types.

[0022] The ions to be removed in the water quality control device 1 may include at least one of the following: heavy metal elements (Fe, Cu, Cr, Mn, Hg, As, Cd), amphoteric elements (Al, Zn, Be, Sn, Pb), and radioactive elements (Cs, Sr, Co, I, Ru, U, Pu, Am, Cm), but are not limited to ions of the listed elements.

[0023] The container 4 housing the ion exchanger to be controlled is preferably structured to adjust the concentration or activity of the ions to be controlled in the water to be treated, and then pass the water to be treated through the ion exchanger. Any configuration is acceptable as long as it houses the ion exchanger to be controlled and the treated water comes into contact with the ion exchanger to be controlled when the treated water is passed through it.

[0024] The controlled ions should preferably include at least one of the following: protons, plutonium ions, hydroxide ions, carbonate ions, and bicarbonate ions.

[0025] Examples of controlled ion exchangers to be housed in the controlled ion exchanger storage container 4 include ion exchange resins, chelate resins, zeolites, hydroxides, hydrotalcite, siliceous titanate compounds, titanate compounds, etc. It is desirable to use at least one of these, or a combination thereof.

[0026] The ion removal device 6 is a device that removes ions to be removed from the water to be treated after the concentration or activity of the ions to be controlled has been adjusted in the ion exchange container 4. Preferably, the ions to be removed are removed by performing at least one of adsorption, precipitation, and oxidation-reduction.

[0027] In this case, when adsorption is performed in the ion removal device 6, it is desirable to use at least one of hydroxide, carbonate, activated carbon, ion exchange resin, chelate resin, zeolite, silicate titanate compound, or titanate compound as the adsorbent.

[0028] Furthermore, when precipitation is performed in the ion removal device 6, it is desirable to use at least one of the following as the precipitating agent: hydroxide, carbonate, calcium salt, iron compound, or organic polymer flocculant.

[0029] When oxidation-reduction is performed in the ion removal device 6, it is desirable to use at least one of the following as the oxidation-reduction agent: hydrogen peroxide, hypochlorite compound, chlorite compound, chlorate compound, perchlorate compound, nitrate compound, permanganate compound, chromate compound, iron compound, sulfite compound, thiosulfate compound, formic acid compound, oxalate compound, ascorbic acid compound, or hydrazine.

[0030] The following are some more specific examples.

[0031] The water to be treated is a waste liquid containing arsenic generated from a waste treatment facility. The purpose is to maintain the performance of cerium hydroxide that adsorbs and removes arsenic. Therefore, the pH of the water to be treated flowing into the removal target ion removal device 6 is controlled between pH 7 and pH 9. In this case, the control target ion is a proton (H + ), and the removal target ion is arsenic.

[0032] As a specific example, FIG. 2 shows the operation when a cation exchanger, such as zeolite, is used as the control target ion exchanger. FIG. 2 shows the state of the ion exchange reaction in the cation exchanger in the control target ion exchanger storage container 4.

[0033] In FIG. 2, in this example, consider the case where the waste liquid sent from the water supply device 2 for the water to be treated is usually about pH 9, but when a large amount of acid is used during waste treatment, an acidic waste liquid with a pH of about 3 to pH 4 is temporarily sent.

[0034] During normal water flow (in (a) in FIG. 2), the water to be treated with a pH of about 9 continues to flow in, and the surface and inside of the cation exchanger have a composition balanced with the pH of this water to be treated. If it is alkaline with a pH of about 9, since the H + concentration in the treated water is low, most of the ions retained in the cation exchanger are cations C + other than H + (for example, sodium ion Na + or potassium ion K + ).

[0035] Here, when the water quality changes and an acidic waste liquid with a pH of about 3 to pH 4 is temporarily sent (in (b) in FIG. 2), during the water quality change, since the H + concentration in the treated water is high, an exchange occurs between C + retained in the cation exchanger and H + in the water to be treated. As a result, H +The concentration decreases. Therefore, even if the pH of the water to be treated at the inlet of the controlled ion exchange container 4 is acidic, ranging from pH 3 to pH 4, the pH of the water to be treated at the outlet of the controlled ion exchange container 4 becomes alkaline, ranging from pH 8. As a result, the pH of the water to be treated that flows into the ion removal device 6 is maintained between pH 7 and pH 9.

[0036] Subsequently, when the water quality recovered after the temporary inflow of acidic wastewater ended (Figure 2 (c)), the pH was around 9, H + As the low-concentration treated water flows into the controlled ion exchanger storage container 4, the composition in the cation exchanger changes toward a composition equilibrium with the pH of this treated water, and the H retained in the cation exchanger + And, C in the water to be treated + An exchange of ions occurs. As a result, the composition of the cation exchanger returns to that of normal water quality (Figure 2(a)).

[0037] Figure 3 shows the calculated time-dependent changes in pH at the inlet and outlet of the controlled ion exchanger storage container 4.

[0038] As shown in Figure 3, even if the pH at the inlet of the controlled ion exchange container 4 changes in a stepwise manner from pH 9 to pH 3.5, the reaction shown in Figure 2 causes the pH at the outlet of the controlled ion exchange container 4 to change with a lag relative to the pH at the inlet, and it can be seen that the pH is maintained within the target range of pH 7 to pH 9.

[0039] Next, the effects of this embodiment will be described.

[0040] The water quality control method of Embodiment 1 of the present invention described above is a water quality control method for treated water containing ions to be controlled and ions to be removed, wherein the treated water is brought into contact with an ion exchanger that adsorbs and desorbs ions to be controlled, and then the ions to be removed are removed from the treated water.

[0041] Furthermore, the water quality control device 1 of Embodiment 1 of the present invention described above is a device for controlling the water quality of water to be treated, which contains ions to be controlled and ions to be removed, and comprises a container 4 for housing ion exchangers that adsorb and desorb ions to be controlled, and a device 6 for removing ions to be removed, which is arranged downstream of the container 4 for housing ion exchangers that adsorb and desorb ions to be controlled.

[0042] This allows, for example, in water treatment to remove heavy metal elements from wastewater containing heavy metal elements, to control the pH of the treated water within an appropriate range even if the water quality of the treated water changes, and to control it within an appropriate range where the performance of the means for removing the ions does not deteriorate, thereby maintaining the removal performance of the ions to be removed.

[0043] Furthermore, for example, in water treatment to remove heavy metal elements from wastewater containing heavy metal elements, the pH of the treated water can be controlled to within the range of wastewater standards, allowing it to be discharged from the water treatment facility. Even if it is not discharged, the treated liquid can be stored in relatively inexpensive stainless steel containers or similar without worrying about deterioration.

[0044] <Example 2> A water quality control method and a water quality control device of Example 2 of the present invention will be described with reference to Figures 4 to 8.

[0045] Figure 4 is a schematic diagram showing the water quality control device of this embodiment 2. The water quality control device 1A of this embodiment shown in Figure 4 is configured to better handle cases where the wastewater sent from the water treatment device 2 is normally pH 3 to pH 4, that is, when the pH of the water to be treated under normal conditions does not fall within the target pH range of pH 7 to pH 9.

[0046] The water quality control device 1A shown in Figure 4 differs from the water quality control device 1 of Example 1 in that it uses a control target ion concentration adjustment device 7 installed on the piping system 3A.

[0047] The ion concentration adjustment device 7 controls the pH according to the flow shown in Figure 5. Figure 5 is a flow diagram showing the procedure for water treatment using the water quality control device 1A.

[0048] As shown in Figure 5, first, the pH concentration range of the water to be treated at the outlet of the controlled ion exchanger storage container 4 is set (S1).

[0049] Subsequently, once the flow of the water to be treated is started (S2), the pH at the outlet of the controlled ion exchanger storage container 4 is monitored, and it is determined whether the pH of the water to be treated at the outlet of the controlled ion exchanger storage container 4 is above the lower limit of concentration (S3).

[0050] If it is determined that the concentration is below the lower limit, the process proceeds to S4, and the control of the target ion concentration by the target ion concentration adjustment device 7 is started (S4), after which the process returns to S2.

[0051] Specifically, alkali metal hydroxide solutions or alkali metal oxide powders are added to the water to be treated to increase the pH. Alternatively, the water to be treated is brought into contact with ammonia gas or alkaline earth metal oxides.

[0052] In response to this, if it is determined in S3 that the concentration is above the lower limit, the process proceeds to S5, where it is determined whether the pH of the water to be treated at the outlet of the controlled ion exchanger storage container 4 is below the upper limit of the concentration (S5).

[0053] If it is determined in S5 that the concentration limit has been exceeded, the process proceeds to S6, the control of the target ion concentration by the target ion concentration adjustment device 7 is stopped (S6), and the process returns to S2.

[0054] In response to this, in S5, if it is determined that the concentration is below the upper limit, the process proceeds to S7, and it is determined whether the target amount of water to be treated has been passed through (S7). If it is determined that the water has been passed through, the process is completed; if it is determined that it has not been completed, the process returns to S2 and the water is passed through.

[0055] Figure 6 shows the results of calculating the time-dependent change in pH at the inlet and outlet of the ion exchange container 4 controlled by the water quality control device 1A in this embodiment.

[0056] As shown in Figure 6, even if the pH at the inlet of the controlled ion exchange container 4 changes alternately between pH 10 and pH 3.5 in a stepwise manner, the reaction shown in Figure 2 causes the pH at the outlet of the controlled ion exchange container 4 to change with a lag relative to the pH at the inlet, and it can be seen that the pH is maintained within the target range of pH 7 to pH 9.

[0057] Figures 7 and 8 show the specific schematic configuration of the water quality control device 1A of Example 2.

[0058] The water quality control device 1A1 in Figure 7 is equipped with a controlled ion concentration adjustment device 71 on the piping 3A1 upstream of the controlled ion exchange container 4, which adjusts the concentration or activity of the controlled ions.

[0059] This controlled ion concentration adjustment device 71 consists of a mixing device 711, a controlled ion doping device 712, and piping 713.

[0060] When the concentration or activity of the target ions in the treated water at the outlet of the ion exchange container 4 is below the lower limit of the specified concentration or activity range, the gas, solution, or powdered solid containing the target ions contained in the ion addition device 712 is supplied to the mixer 711 via piping 713 and added to the treated water supplied from the treated water supply device 2 within the mixer 711 to control the concentration of the target ions. Conversely, when the concentration or activity of the target ions in the treated water at the outlet of the ion exchange container 4 is above the upper limit of the specified concentration or activity range, the supply of the gas, solution, or powdered solid containing the target ions from the ion addition device 712 is stopped.

[0061] Furthermore, the substance contained in the ion doping device 712 is not limited to gases, solutions, or powdered solids containing the ions to be controlled, but may also be a gas, solution, or powdered solid that reacts with the ions to be controlled.

[0062] Furthermore, the water quality control device 1A2 in Figure 8 is equipped with a controlled ion concentration adjustment device 72 on the piping 3A2 upstream of the controlled ion exchange container 4, which adjusts the concentration or activity of the controlled ions.

[0063] This controlled ion concentration adjustment device 72 consists of a controlled ion additive storage container 721, a three-way valve 722, and piping 723.

[0064] When the concentration or activity of the target ions in the treated water at the outlet of the ion exchange container 4 is below the lower limit of the specified concentration or activity range, the three-way valve 722 is set to conduct electricity on the side of the piping 3 connected to the ion additive container 721, thereby controlling the concentration of the target ions by bringing the gas or solid packing material containing the target ions contained in the ion additive container 721 into contact with the treated water. Conversely, when the concentration or activity of the target ions in the treated water at the outlet of the ion exchange container 4 is above the upper limit of the specified concentration or activity range, the three-way valve 722 is set to conduct electricity on the side of the piping 723 that bypasses the ion additive container 721.

[0065] Furthermore, the substance contained in the container 721 for the ion additive to be controlled is not limited to a gas or solid packing material containing the ion to be controlled, but may also be a gas or solid packing material that reacts with the ion to be controlled.

[0066] The other configurations and operations are substantially the same as those of the water quality control method and water quality control device described in Example 1 above, and details are omitted.

[0067] In the water quality control method and water quality control device 1A of Example 2 of the present invention, substantially the same effects as those of the water quality control method and water quality control device of Example 1 described above can be obtained.

[0068] Furthermore, upstream of the ion exchange container 4, the system is further equipped with ion concentration adjustment devices 7, 71, and 72 for adjusting the concentration or activity of the ions to be controlled. In particular, the ion concentration adjustment devices 71 and 72 can be either a ion additive container 721, a three-way valve 722, and piping 723 for contacting the water to be treated with a gas or solid containing or reacting with the ions to be controlled, or a mixing device 711, an ion additive device 712, and piping 713 for adding a solution or solid containing or reacting with the ions to be controlled to be controlled to the water to be treated. This allows the concentration of ions to be controlled in the water flowing into the ion removal device 6 to be controlled within an appropriate range, even if the concentration of ions to be controlled in the water to be treated, supplied from the water to be treated, deviates significantly outside the target range during normal operation.

[0069] <Example 3> Figure 3 shows the water quality control method and water quality control device of the present invention. 9 This will be explained using the following. Figure 9 is a schematic diagram showing the water quality control device of this embodiment 3.

[0070] The water quality control device 1B of this embodiment, shown in Figure 9, further includes a system for supplying two or more water treatment systems upstream of the ion exchanger storage container 4 to be controlled. In Figure 9, a water treatment system 8, which supplies water treatment systems separate from the water treatment system 2, is connected to the system of piping 3B via piping 9.

[0071] For example, in the water quality control device 1B, treated water A, whose pH is above the upper limit of the target range, is supplied from the treated water supply device 2, and treated water B, whose pH is below the lower limit of the target range, is supplied from the treated water supply device 8.

[0072] By alternately passing the treated water A and treated water B through the controlled ion exchanger housing container 4, the pH of the treated water flowing into the ion removal device 6 can be controlled to an appropriate range, similar to Example 2.

[0073] Furthermore, the method is not particularly limited; at least two types of water to be treated may be prepared, each with a different concentration or activity of the target ions, and the water may be passed through the ion exchanger while switching between the two types of water.

[0074] The other configurations and operations are substantially the same as those of the water quality control method and water quality control device 1 described in Example 1, and details are omitted.

[0075] In the water quality control method and water quality control device 1B of Example 3 of the present invention, substantially the same effects as those of the water quality control method and water quality control device 1 of Example 1 described above can be obtained.

[0076] Furthermore, the system is further equipped with a system for supplying two or more water treatments upstream of the ion exchange container 4, and by providing at least two types of water treatments with different concentrations or activities of the ions to be controlled, and by switching between the water treatments as they are passed through the ion exchange, it is not necessary to add gases, solutions, or solids to adjust the concentration of the ions to be controlled, thus reducing the amount of chemicals used and waste. [Explanation of Symbols]

[0077] 1,1A,1A1,1A2,1B: Water quality control device 2,8: Water supply equipment for treated water 3,3A,3A1,3A2,3B,5,9: Piping 4: Controlled ion exchanger storage container (storage container) 6: Ion removal device (removal unit) 7,71,72: Controlled ion concentration adjustment device (adjustment unit) 711: Mixing device (addition section) 712: Controlled ion doping device (doping section) 713: Piping (Additional part) 721: Container for ion dopant material to be controlled (contact area) 722: Three-way valve (contact part) 723: Piping (contact part)

Claims

1. A method for controlling the water quality of treated water, which includes ions to be controlled that contain protons and ions to be removed that contain radioactive elements, The water to be treated is brought into contact with an ion exchanger that adsorbs and desorbs ions, and the target ions containing protons are exchanged with the ions held in the ion exchanger. It is determined whether the concentration or activity of the target ion containing the proton in the treated water after contact with the ion exchanger is within a predetermined concentration or activity range. If, based on the above determination, the concentration or activity of the ion to be controlled, including the proton, is outside the predetermined range of concentration or activity, the ion to be controlled, including the proton, or its activity is adjusted before ion exchange by the ion exchanger. The target ions, including the radioactive element, are removed from the treated water after contact with the ion exchanger. Water quality control methods.

2. A method for controlling the water quality of treated water, which includes ions to be controlled that contain protons and ions to be removed that contain radioactive elements, At least two types of water to be treated are prepared, each with a different concentration or activity of the target ion containing the proton. At least two types of water to be treated, each with a different concentration or activity of the target ions including the proton, are passed through the ion exchanger while switching between them. Removes the target ions containing the radioactive element from the treated water. Water quality control methods.

3. In the water quality control method described in claim 1, Based on the above determination, When the concentration or activity of the ion to be controlled, including the proton, exceeds a predetermined upper limit of concentration or activity, the concentration or activity of the ion to be controlled, including the proton, is reduced before ion exchange by the ion exchanger. When the concentration or activity of the ion to be controlled, which includes the proton, falls below a predetermined lower limit of concentration or activity, the adjustment of the concentration or activity of the ion to be controlled, which includes the proton, is stopped. Water quality control methods.

4. In the water quality control method described in claim 1, In the step of removing the ions to be removed from the treated water, at least one of adsorption, precipitation, and oxidation-reduction is performed. Water quality control methods.

5. In the water quality control method according to any one of claims 1 to 4, The ion to be controlled, which includes a proton, contains at least one of the following: proton, plutonium ion, hydroxide ion, carbonate ion, and bicarbonate ion. Water quality control methods.

6. In the water quality control method according to any one of claims 1 to 4, As the ion exchanger, at least one of the following is used: ion exchange resin, chelate resin, zeolite, hydroxide, hydrotalcite, silicate titanate compound, and titanate compound. Water quality control methods.

7. In the water quality control method according to any one of claims 1 to 4, The ions to be removed include at least one of the following: heavy metal elements (Fe, Cu, Cr, Mn, Hg, As, Cd), amphoteric elements (Al, Zn, Be, Sn, Pb), and radioactive elements (Cs, Sr, Co, I, Ru, U, Pu, Am, Cm). Water quality control methods.

8. In the water quality control method described in claim 4, As the adsorbent used for the aforementioned adsorption, at least one of hydroxide, carbonate, activated carbon, ion exchange resin, chelate resin, zeolite, silicate titanate compound, or titanate compound may be used. Water quality control methods.

9. In the water quality control method described in claim 4, As the precipitating agent used in the aforementioned precipitation, at least one of hydroxides, carbonates, calcium salts, and organic polymer flocculants is used. Water quality control methods.

10. In the water quality control method described in claim 4, At least one of the following is used as the redox agent for the aforementioned oxidation-reduction: hydrogen peroxide, hypochlorite compound, chlorite compound, chlorate compound, perchlorate compound, nitrate compound, permanganate compound, chromate compound, iron compound, sulfite compound, thiosulfate compound, formic acid compound, oxalate compound, ascorbic acid compound, and hydrazine. Water quality control methods.

11. A water quality control device for controlling the water quality of treated water containing target ions including protons and target ions including radioactive elements, A storage container for an ion exchanger that adsorbs and desorbs the target ions containing the aforementioned protons, An adjustment unit is located upstream of the storage container and adjusts the concentration or activity of the target ions, including protons, before ion exchange by the ion exchanger when the concentration or activity of the target ions in the water to be treated at the outlet of the storage container is outside a predetermined range. The storage container is equipped with a removal unit located downstream of the storage container, which removes ions to be removed, including the radioactive element. Water quality control device.

12. In the water quality control device according to claim 11, The adjustment unit is, When the upper limit of the predetermined range is exceeded, the concentration or activity of the control target ion containing the proton is adjusted to decrease. When the value is below the lower limit of the predetermined range, the adjustment of the concentration or activity of the controlled ion containing the proton is stopped. Water quality control device.

13. In the water quality control device according to claim 11, The adjustment unit is, A contact section containing a gas or solid that reacts with the target ion containing the proton, It consists of a pipe connecting the inlet and outlet pipes of the contact portion, and a three-way valve positioned in the inlet pipe of the contact portion. The three-way valve switches the piping connections according to the concentration or activity of the target ions in the treated water at the outlet of the storage container. A water quality control device characterized by the following features.

14. A water quality control device for controlling the water quality of treated water containing ions to be controlled and ions to be removed, A storage container for an ion exchanger that adsorbs and desorbs target ions containing protons, Upstream of the storage container, there are two or more systems for supplying the water to be treated, The storage container is provided with a removal unit located downstream of the storage container for removing the target ions. Water quality control device.

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