TW201725181A - Water treatment device and water treatment method - Google Patents

Abstract

The invention provides a water treatment device and water treatment method that can lower the concentration of boron in the treated water. A plurality of electrical deionized water production devices comprise desalination chambers, which are positioned between an anode and a cathode, are partitioned by an anion exchange membrane positioned on the anode side and a cation exchange membrane positioned on the cathode side, and are filled with ion exchangers, wherein the desalination chambers of the plurality of electrical deionized water production devices are linked in series, and the water to be treated passes through, and is then discharged as treated water from, the plurality of series-linked desalination chambers. The most upstream section of the first stage desalination chamber through which the water to be treated initially passes and the most downstream section of the final stage desalination chamber from which the treated water is discharged are independently filled with anion exchangers, and a portion of the plurality of desalination chambers positioned between the most upstream section of the first stage desalination chamber and the most downstream section of the final stage desalination chamber are filled with at least a cation exchanger.

Description

Water treatment device and water treatment method

The present invention relates to a water treatment device and a water treatment method, and more particularly to a water treatment device and a water treatment method using an electric deionized water production device.

A deionized water producing apparatus which conducts ion-exchanged water of an ion exchange resin or the like and performs deionization by an ion exchange reaction is conventionally known. In such a device, when the ion exchange group of the ion exchanger is saturated and the desalination performance is lowered, it is necessary to carry out the treatment (regeneration treatment) of the regenerated ion exchanger by a chemical such as an acid or a base. The regeneration treatment replaces a cation (positive ion) or an anion (negative ion) adsorbed on the ion exchanger by hydrogen ions (H ⁺ ) or hydroxide ions (OH ^- ) derived from an acid or a base, thereby causing the ion exchanger The treatment of the desalination performance recovery. The deionized water production apparatus which requires the drug regeneration treatment has a problem that it cannot be continuously operated, and the replenishing of the medicine for reprocessing is also laborious.

In recent years, an electric deionized water producing apparatus (also referred to as an EDI (Electro DeIonization) apparatus) that does not require regeneration of a chemical to solve such problems has been developed and put into practical use. The EDI device is a combination electrophoresis and electrodialysis device. The EDI apparatus has a desalination chamber in which an ion exchanger (an anion exchanger and/or a cation exchanger) is filled between an anion exchange membrane that transmits only anions and a cation exchanger that transmits only a cation. In the EDI apparatus, a concentration chamber is disposed outside each of the exchange membranes of the anion exchange membrane and the cation exchange membrane as seen from the desalination chamber. Further, the desalting compartment and each concentration chamber are disposed between the anode chamber having the anode and the cathode chamber having the cathode. In the desalination chamber, an anion exchange membrane is disposed on the side close to the anode, and a cation exchange membrane is disposed on the side close to the cathode. A concentrating chamber adjacent to the desalting chamber through the anion exchange membrane is passed through the cation exchange membrane adjacent to the anode chamber. A concentrating chamber adjacent to the desalting chamber through the cation exchange membrane is passed through the anion exchange membrane adjacent to the cathode chamber.

In order to produce deionized water (treated water) from the water to be treated by the EDI device, the water to be treated is introduced into the desalting compartment in a state where a direct current voltage is applied between the anode and the cathode. Thus, the ion component in the water to be treated is adsorbed on the ion exchanger in the deionization chamber, and deionization (desalting) treatment is performed, and then the deionized water is discharged from the desalting compartment. At this time, in the desalination chamber, by applying a voltage, an interface between different kinds of ion-exchange substances, for example, an interface between an anion exchanger and a cation exchanger, an interface between an anion exchanger and a cation exchange membrane, and an anion exchange membrane and The interface of the cation exchanger or the like generates a dissociation reaction of water as shown by the following formula, and generates hydrogen ions and hydroxide ions. H ₂ O®H ⁺ +OH ^-

The ion component adsorbed on the ion exchanger in the deionization chamber is ion-exchanged and released from the ion exchanger by the hydrogen ion and the hydroxide ion. Among the free ionic components, anions are electrophoresed to an anion exchange membrane and electrodialyzed by an anion exchange membrane, followed by discharge of concentrated water flowing through the concentrating compartment on the anode side as viewed from the desalting compartment. Similarly, in the free ionic component, the cation is electrophoresed to the cation exchange membrane and electrodialyzed by the cation exchange membrane, and then the concentrated water flowing through the concentrating compartment on the cathode side as viewed from the desalting compartment is discharged. Finally, the ion component supplied to the treated water in the desalting compartment is moved to the concentration chamber and discharged, and the ion exchanger of the desalting compartment is also regenerated.

As described above, in the EDI apparatus, hydrogen ions and hydroxide ions generated by applying a DC voltage continuously act as a regenerant for regenerating the acid and alkali of the ion exchanger. Therefore, in the EDI apparatus, it is basically unnecessary to carry out the regeneration treatment by the externally supplied medicine, and it is possible to carry out the continuous continuous rotation without regenerating the ion exchanger by the medicine.

Japanese Laid-Open Patent Publication No. 2001-191080 discloses an electric deionization apparatus in which respective desalination chambers of two EDI devices are connected in series. In the electrical deionization apparatus described in this patent document, an anion exchanger is separately filled in a desalting chamber of a first stage, or a mixture of an anion exchanger and a cation exchanger is filled, and an anion is filled in a desalting chamber of the second stage. a mixture of exchangers and cation exchangers.

Nowadays, there is a demand for low concentration of boron in treated water (deionized water), and it is desirable to have a water treatment technology that can be recycled. It is an object of the present invention to provide a water treatment apparatus and a water treatment method which can reduce the concentration of boron in treated water.

The water treatment device of the present invention is a water treatment device having a plurality of electric deionized water production devices, and each of the electric deionized water production devices of the above-described electric deionized water production device has between an anode and a cathode. a desalination chamber which is separated by an anion exchange membrane located on the anode side and a cation exchange membrane located on the cathode side, and is filled with an ion exchanger, and each of the aforementioned desalting chambers of the plurality of electric deionized water producing apparatuses The plurality of desalination chambers that are connected in series are connected to the treated water and flow out the treated water, and the upstream portion of the desalination chamber of the first stage in which the water to be treated is initially introduced and the treated water are discharged. The most downstream portion of the desalination chamber in the final stage is separately filled with an anion exchanger, and a portion of the plurality of desalting chambers is located between the most upstream portion of the first stage desalination chamber and the most downstream portion of the final stage desalination chamber. The portion is at least filled with a cation exchanger.

The water treatment method of the present invention uses a water treatment apparatus comprising a majority of an electrically deionized water producing apparatus having a desalination chamber between an anode and a cathode, the desalination chamber being located by an anion exchange membrane located on the anode side The cation exchange membrane on the cathode side is partitioned and filled with an ion exchanger, and each of the aforementioned desalination chambers of the plurality of electric deionized water production apparatuses are connected in series, and a plurality of desalination chambers connected in series are processed. The water flows out of the treated water, and the anion exchanger is separately filled in the most upstream portion of the first desalting chamber in the first stage in which the water to be treated is first introduced, and the most downstream portion of the desalting chamber in the final stage in which the treated water is discharged. And at least a part of the plurality of desalting chambers located between the most upstream portion of the first-stage desalting chamber and the most downstream portion of the final stage desalination chamber is filled with at least a cation exchanger, the water treatment method being on the anode and the foregoing A DC voltage is applied between the cathodes, and the treated water is introduced into a plurality of desalination chambers connected in series. The effluent water to be treated and the treated water.

According to the present invention, each of the desalination chambers of the majority of the electric deionized water producing apparatus is connected in series, and a plurality of desalination chambers connected in series are in the most upstream part of the first stage desalination chamber and the most downstream of the final stage desalination chamber. The portion is separately filled with an anion exchanger, and a portion between them is filled with at least a cation exchanger. Therefore, as can be understood from the examples and the like described later, the anion exchange is filled in the water treatment device in which the mixture of the anion exchanger and the cation exchanger is filled in the desalination chamber of the first stage, or in the most downstream portion of the final stage desalination chamber. The water treatment device of the mixture of the body and the cation exchanger can reduce the concentration of boron in the treated water.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. A water treatment device according to an embodiment of the present invention includes a plurality of EDI devices (electrical deionized water production devices). In the EDI apparatus, an ion exchanger is filled in the desalting compartment, and ions trapped by the ion exchange reaction move along the ion exchanger to the ion exchange membrane. Therefore, ions can be effectively removed. Further, in the EDI device, the current flows at a current density generated by the decomposition reaction of water. The minimum current generated by the decomposition reaction of water is called the limiting current, and the current above the limiting current flows in the EDI device. Therefore, even when the ion concentration in the water to be treated is low, hydrogen ions and hydroxide ions generated in the decomposition reaction of water move along the ion exchanger to the ion exchange membrane, and the charge is moved. As described above, in the EDI apparatus, even if it is operated in pure water, pure water can be produced. On the other hand, the electrodialysis device (ED) does not fill the ion exchange body in the desalting compartment, and flows a current smaller than the limit current, so that the decomposition reaction of water cannot be utilized.

First, six types of EDI devices 101 to 106 used in the embodiment of the present invention will be described. The patterns of the desalting chambers of the six EDI devices are different from each other.

<EDI Device 101> FIG. 1 is a view showing the EDI device 101. In the EDI apparatus 101, between the anode chamber 21 having the anode 11 and the cathode chamber 25 having the cathode 12, a concentration chamber 22, a desalting chamber 23a, and a concentration chamber 24 are sequentially provided from the anode chamber 21 side.

The anode chamber 21 and the concentrating chamber 22 are adjacent to each other via the cation exchange membrane 31, and the concentrating chamber 22 and the desalting chamber 23a are adjacent to each other via the anion exchange membrane 32, and the desalting chamber 23a and the concentrating chamber 24 are adjacent to each other via the cation exchange membrane 33, and the concentrating chamber 24 and The cathode chamber 25 is adjacent to each other via the anion exchange membrane 34. The concentrating compartment 24 is an example of a first concentrating compartment, and the concentrating compartment 22 is an example of a second concentrating compartment.

The desalting compartment 23a is partitioned by an anion exchange membrane 32 and a cation exchange membrane 33. The anion exchanger AER is filled in a single bed form in the desalting compartment 23a. The anion exchanger AER uses, for example, an anion exchange resin. The treated water is passed into the desalting compartment 23a.

Feed water is introduced into each of the concentrating chambers 22 and 24, the anode chamber 21, and the cathode chamber 25. Pure water, treated water, etc. are used for the supply water.

The water supply direction of the supply water to the concentration chambers 22 and 24 is opposite to the water flow direction of the water to be treated to the desalination chamber 23a. The water supply direction of the supply water to the anode chamber 21 and the cathode chamber 25 is opposite to the water passage direction of the water to be treated to the desalination chamber 23a. Further, the relationship of the water passing directions can be appropriately changed. Further, the electrode water discharged from the cathode chamber 25 flows into the anode chamber 21 as supply water. Further, the electrode water discharged from the anode chamber 21 may also flow into the cathode chamber 25 as supply water.

<EDI Device 102> FIG. 2 is a diagram showing the EDI device 102. The ion exchanger filled in the desalination chamber of the EDI device 102 is different from the EDI device 101 shown in FIG. In the desalination chamber 23b of the EDI apparatus 102, the anion exchanger AER is separately filled in the region of the inlet side 23b1 of the treated water, and the cation exchanger CER is separately filled in the region of the outlet side 23b2. The cation exchanger CER uses, for example, a cation exchange resin.

<EDI Device 103> FIG. 3 is a diagram showing the EDI device 103. Compared to the EDI device 102 shown in FIG. 2, the position of the anion exchanger AER and the cation exchanger CER filled in the desalting compartment of the EDI device 103 is reversed. That is, in the desalination chamber 23c of the EDI apparatus 103, the cation exchanger CER is separately filled in the region of the inlet side 23c1 of the water to be treated, and the anion exchanger AER is separately filled in the region of the outlet side 23c2.

<EDI Device 104> FIG. 4 is a diagram showing the EDI device 104. In the desalination chamber 23d of the EDI device 104, an intermediate ion exchange membrane 36 is provided between the anion exchange membrane 32 and the cation exchange membrane 33, and the desalting compartment 23d is partitioned into a small desalting compartment 23d-1 by the intermediate ion exchange membrane 36. And small desalting chamber 23d-2. As the intermediate ion exchange membrane 36, any of a composite membrane such as an anion exchange membrane, a cation exchange membrane, and a bipolar membrane can be used. In the EDI device 104, the intermediate ion exchange membrane 36 uses an anion exchange membrane. The small desalting compartment 23d-1 on the anode side is an example of the first small desalting compartment, and the small demineralization compartment 23d-2 on the cathode side is an example of the second small desalting compartment.

The anion exchanger AER is filled in a single bed form in the small desalting compartment 23d-1, and the cation exchanger CER is filled in a single bed form in the small desalting compartment 23d-2. The small desalting compartment 23d-1 and the small desalting compartment 23d-2 are connected in series, and the treated water is introduced into the small desalting compartment 23d-1 and then the water flowing out of the small desalting compartment 23d-1 flows into the small desalting compartment 23d-2 (please Refer to arrow 104a, arrow 104b, arrow 104c).

The water supply direction of the supply water to the concentrating chambers 22 and 24 is in a countercurrent relationship with the water passing direction of the water to be treated to the small desalination chambers 23d-1 and 23d-2. The water supply direction of the supply water to the anode chamber 21 and the cathode chamber 25 is in a countercurrent relationship with the water passage direction of the water to be treated to the small desalination chambers 23d-1 and 23d-2. Further, the relationship of the water passing directions can be appropriately changed. The electrode water discharged from the cathode chamber 25 flows into the anode chamber 21 as supply water. Further, the electrode water discharged from the anode chamber 21 may also flow into the cathode chamber 25 as supply water.

<EDI Device 105> FIG. 5 is a diagram showing the EDI device 105. Compared with the EDI device 104 shown in FIG. 4, the water passing through the treated water in the first small desalting chamber and the second small desalting chamber of the EDI device 105 is reversed. In the EDI apparatus 105, the small desalting compartment 23e-1 and the small desalting compartment 23e-2 are connected in series, and the water to be treated is supplied to the small desalting compartment 23e-2 and then the water flowing out of the small desalting compartment 23e-2 flows into the small desalting. Room 23e-1 (please refer to arrow 105a, arrow 105b, arrow 105c).

The water supply direction of the supply water to the concentrating chambers 22 and 24 is in a countercurrent relationship with the water passing direction of the water to be treated to the small desalination chambers 23e-1 and 23e-2. The water supply direction of the supply water to the anode chamber 21 and the cathode chamber 25 is in a countercurrent relationship with the water passage direction of the water to be treated to the small desalination chambers 23e-1 and 23e-2. Further, the relationship of the water passing directions can be appropriately changed. The electrode water discharged from the cathode chamber 25 flows into the anode chamber 21 as supply water. Further, the electrode water discharged from the anode chamber 21 may also flow into the cathode chamber 25 as supply water.

<EDI Device 106> FIG. 6 is a diagram showing the EDI device 106. Compared to the EDI device 104 shown in FIG. 4, the ion exchanger of the EDI device 106 filled in the small deionization chamber on the cathode side is different. In the small desalination chamber 23f-2, the region of the inlet side 23f-21 of the water flowing out of the small desalination chamber 23f-1 is separately filled with the cation exchanger CER, and the region of the outlet side 23f-22 is separately filled with the anion exchanger. AER. In the EDI apparatus 106, the small desalting compartment 23f-1 and the small desalting compartment 23f-2 are connected in series, and the water to be treated is supplied to the small desalting compartment 23f-1 and then the water flowing out of the small desalting compartment 23f-1 flows into the small desalting. Room 23f-2 (please refer to arrow 106a, arrow 106b, arrow 106c). The water passing direction of the treated water in the small desalination chamber 23f-1 and the small desalting chamber 23f-2 is in a countercurrent relationship. Further, the intermediate ion exchange membrane 36 uses an anion exchange membrane.

The water supply direction of the supply water to the concentrating chambers 22 and 24 is in a countercurrent relationship with the water passing direction of the water to be treated to the small desalination chamber 23f-2. The water supply direction of the supply water to the anode chamber 21 and the cathode chamber 25 is in parallel with the water passage direction of the water to be treated to the small desalination chamber 23f-2. Further, the relationship of the water passing directions can be appropriately changed. The electrode water discharged from the cathode chamber 25 flows into the anode chamber 21 as supply water. Further, the electrode water discharged from the anode chamber 21 may also flow into the cathode chamber 25 as supply water.

<First Embodiment> Fig. 7 is a view showing a water treatment device 201 according to a first embodiment of the present invention. The water treatment device 201 has an EDI device 102 and an EDI device 103. The desalting compartment 23b of the EDI device 102 and the desalting compartment 23c of the EDI device 103 are connected in series in series. The water that has flowed out from the outlet side 23b2 of the desalination chamber 23b flows into the desalination chamber 23c from the inlet side 23c1. Supply water (pure water) is supplied between the EDI device 102 and the EDI device 103 while the concentrating chambers are not connected in series. The supply water (pure water) is supplied to the electrode chamber (cathode chamber, anode chamber) of the EDI device 102 and the electrode chamber (cathode chamber, anode chamber) of the EDI device 103, respectively. Further, a concentrating chamber may be connected in series between the EDI device 102 and the EDI device 103. The common supply water can also be supplied to the electrode chamber (cathode chamber, anode chamber) of the EDI device 102 and the electrode chamber (cathode chamber, anode chamber) of the EDI device 103.

Further, in the water treatment device according to the embodiment and the embodiments described below, the upstream side of the flow direction of the water to be treated of the EDI device in the preceding stage, that is, the first stage desalination chamber into which the treated water is initially introduced The upstream side of the flow direction of the treated water is preferably provided with a reverse osmosis membrane device 111. The reverse osmosis membrane device 111 can reduce the cerium oxide concentration of the water to be treated to, for example, 100 μg SiO ₂ /L or less, and reduce the boron concentration of the water to be treated to, for example, 100 μg B/L or less. Although not shown in the drawings, it is more preferable to provide two reverse osmosis membrane devices 111 in series. Further, it is preferable to provide the decarbonation membrane device 112 on the upstream side in the flow direction of the water to be treated of the front stage EDI device, that is, on the upstream side in the flow direction of the water to be treated of the first stage demineralization chamber into which the treated water is initially introduced. The decarbonation membrane device 112 can reduce the carbonic acid concentration of the water to be treated to, for example, 5 mg CO ₂ /L or less. Any of the reverse osmosis membrane device 111 and the decarbonation membrane device 112 may be located on the upstream side in the flow direction of the water to be treated.

Next, the water treatment performed in the desalination chambers 23b and 23c of the water treatment device 201 will be described.

In the EDI devices 102 and 103, the desalting chamber 23b of the EDI device 102 is supplied in a state where the supply water is supplied to the anode chamber 21, the concentrating chambers 22 and 24, and the cathode chamber 25, and a direct current voltage is applied between the anode 11 and the cathode 12. The inlet side 23b1 is supplied with treated water.

In the EDI device 102, it is presumed that the treated water is subjected to the following processing. When the boron in the treated water contacts the anion exchanger AER filled in the inlet side 23b1 region of the desalting compartment 23b, it dissociates into an anion and adsorbs on the anion exchanger AER. Further, a part of boron in the water to be treated is not adsorbed on the anion exchanger AER and remains in the water to be treated. The treated water remaining with boron flows into a portion (region) in which the cation exchanger CER is filled in the desalting compartment 23b.

At this time, in the desalination chamber 23b, a dissociation reaction of water is generated by an applied voltage between the anode 11 and the cathode 12, and hydrogen ions and hydroxide ions are generated. Thus, the anion (boron) adsorbed on the anion exchanger AER in the desalting compartment 23b is ion-exchanged by the hydroxide ion and freed by the anion exchanger AER. The free anion moves through the anion exchange membrane 32 to the concentrating compartment 22, and is then discharged from the concentrating compartment 22 into concentrated water.

When the water to be treated in which the portion of the anion exchanger AER is filled in the desalination chamber 23b flows into the portion of the deionization chamber 23b where the cation exchanger CER is filled, the cation contained in the water to be treated is adsorbed on the cation exchanger CER. Next, the cation adsorbed on the cation exchanger CER is ion-exchanged by hydrogen ions generated by the dissociation reaction of water and released from the cation exchanger CER. The free cations are moved to the concentrating chamber 24 through the cation exchange membrane 33, and then discharged into the concentrated water by the concentrating chamber 24.

The hydroxide ions in the water to be treated are moved to the concentration chamber 22 through the anion exchange membrane 32, and then discharged into the concentrated water by the concentration chamber 22.

Further, the hydroxide ions in the water to be treated react with hydrogen ions ion-exchanged by the cation exchanger CER and hydrogen ions generated by hydrolysis to form water (H ₂ O). Therefore, the concentration of hydroxide ions in the water to be treated flowing out of the desalination chamber 23b is lower than in the case where the cation exchanger CER is not present in the desalting compartment 23b. In addition, hydroxide ions in the treated water may be adsorbed on the anion exchanger AER instead of boron (anion). Therefore, when the concentration of hydroxide ions in the treated water is too high, the adsorption efficiency of boron (anion) of the latter anion exchanger AER may be lowered. Therefore, the hydroxide ions in the treated water react with the hydrogen ions adsorbed on the cation exchanger CER to become water (H ₂ O), thereby reducing the boron (anion) adsorption of the anion exchanger AER in the EDI device 103 in the latter stage. The efficiency is getting better.

The water to be treated which has flowed out from the desalination chamber 23b of the EDI device 102 flows into the desalination chamber 23c of the EDI device 103 from the inlet side 23c1.

In the EDI device 103, it is estimated that the following processing is performed. When the water to be treated which flows out of the desalination chamber 23b flows into the region where the cation exchanger CER is filled in the desalination chamber 23c, the water to be treated is treated in the same manner as the treatment in the region where the cation exchanger CER is filled in the desalting compartment 23b. Therefore, the concentration of hydroxide ions in the water to be treated flowing out of the region where the cation exchanger CER is filled in the desalination chamber 23c is lower than that in the case where the cation exchanger CER is not present in the desalting compartment 23c.

The water to be treated in the region where the cation exchanger CER is filled in the desalination chamber 23c flows into the region where the anion exchanger AER is filled in the desalting chamber 23c.

When the boron in the treated water contacts the anion exchanger AER filled in the outlet side 23c2 of the desalting compartment 23c, it dissociates into an anion and adsorbs on the anion exchanger AER. At this time, since the water to be treated passes through the cation exchanger CER, the concentration of hydroxide ions in the water to be treated is lower than before passing through the cation exchanger CER. Therefore, the boron (anion) adsorption efficiency of the anion exchanger AER filled in the outlet side 23c2 region of the desalination chamber 23c is improved. Therefore, the boron in the treated water flowing out of the desalination chamber 23c can be made low in concentration.

In addition, boron can be made low in the treated water by using a majority of EDI devices. Therefore, the following effects can be achieved by, for example, filling the ion exchanger in the order of "anion exchanger + cation exchanger + anion exchanger" in the desalting compartment of one EDI apparatus.

(1) It is possible to suppress the bias current of the current in the EDI device. For example, when the ion exchanger is filled in the order of "anion exchanger + cation exchanger + anion exchanger" in the desalination chamber of one EDI device, the resistance between the anion exchanger and the cation exchanger is different, so The difference produces a bias current. On the other hand, when a large number of EDI devices are used, the type of ion exchanger filled in one desalination chamber can be reduced as compared with the case of using one EDI device, so that current bias due to the difference in resistance of the ion exchanger can be reduced. .

(2) Since the electrode plate can be dispensed, it is easy to control the current value. The electrode plate is easily deteriorated when the current density is high. Further, when the ion exchange membrane or the ion exchange resin constituting the EDI apparatus is operated at a high current value in a state where the ion load is small, deterioration such as electrical burnout tends to occur. For example, by reducing the current value of the EDI device after the ion load is low, a more stable operation should be possible.

(3) It can reduce the load on the rear EDI device. Since the latter stage EDI apparatus processes the treated water treated in the preceding stage EDI apparatus, the processing load is lowered as compared with the case of treating the completely untreated treated water. Therefore, the degree of deterioration of the latter stage EDI device is also less than that of the previous stage EDI device, so it can be assumed that a longer time can be used. The switching frequency of the rear EDI device should be less than that of the previous EDI device.

<Second embodiment> Fig. 8 is a view showing a water treatment device 202 according to a second embodiment of the present invention. The water treatment device 202 has an EDI device 101 and an EDI device 103. The desalting compartment 23a of the EDI device 101 and the desalting compartment 23c of the EDI device 103 are connected in series in series. The water to be treated flows into the desalination chamber 23a. Next, the water flowing out of the desalination chamber 23a flows into the desalination chamber 23c from the inlet side 23c1. The supply water is supplied between the EDI device 101 and the EDI device 103 while the concentrating chambers are not connected in series. The supply water is supplied to the electrode chamber (cathode chamber, anode chamber) of the EDI device 101 and the electrode chamber (cathode chamber, anode chamber) of the EDI device 103, respectively.

Next, the water treatment performed in the desalination chambers 23a and 23c of the water treatment device 202 will be described. In the EDI devices 101 and 103, the desalination chamber of the EDI device 101 is opened while supplying the supply water to the anode chamber 21, the concentrating chambers 22 and 24, and the cathode chamber 25 and applying a direct current voltage between the anode 11 and the cathode 12. 23a is passed into the treated water.

In the EDI apparatus 101, the same processing as that performed by using the anion exchanger AER filled in the inlet side 23b1 region of the demineralization chamber 23b of the first embodiment is estimated. The water to be treated which has flowed out from the desalination chamber 23a of the EDI device 101 flows into the desalination chamber 23c of the EDI unit 103 from the inlet side 23c1. In the EDI device 103, the same processing as that performed by the EDI device 103 shown in the first embodiment is estimated.

Therefore, similarly to the first embodiment, the boron (anion) adsorption efficiency of the anion exchanger AER filled in the region of the outlet side 23c2 of the desalination chamber 23c is improved. Therefore, the boron in the treated water flowing out of the desalination chamber 23c can be made low in concentration.

<Third Embodiment> Fig. 9 is a view showing a water treatment device 203 according to a third embodiment of the present invention. The water treatment device 203 has an EDI device 102 and an EDI device 101. The desalting compartment 23b of the EDI device 102 and the desalting compartment 23a of the EDI device 101 are connected in series in series. The water to be treated flows into the desalination chamber 23b from the inlet side 23b1. The water flowing out of the desalination chamber 23b flows into the desalination chamber 23a. The supply water is supplied between the EDI device 102 and the EDI device 101 while the concentrating chambers are not connected in series. The supply water is supplied to the electrode chamber (cathode chamber, anode chamber) of the EDI device 102 and the electrode chamber (cathode chamber, anode chamber) of the EDI device 101, respectively.

Next, the water treatment performed in the desalination chambers 23b and 23a of the water treatment device 203 will be described. In the EDI devices 102 and 101, the desalination chamber of the EDI device 102 is opened while supplying the supply water to the anode chamber 21, the concentrating chambers 22 and 24, and the cathode chamber 25 and applying a direct current voltage between the anode 11 and the cathode 12. The inlet side 23b1 of 23b is supplied with treated water. In the EDI device 102, the same processing as that performed by the EDI device 102 shown in the first embodiment is estimated. The water to be treated which has flowed out from the outlet side 23b2 of the desalination chamber 23b of the EDI device 102 flows into the desalination chamber 23a of the EDI device 101. In the EDI apparatus 101, the same processing as that performed by using the anion exchanger AER filled in the outlet side 23c2 region of the demineralization chamber 23c of the first embodiment is estimated.

Therefore, similarly to the first embodiment, the boron (anion) adsorption efficiency of the anion exchanger AER filled in the desalination chamber 23a is improved, and the boron in the treated water flowing out of the desalination chamber 23a can be made low in concentration.

<Fourth embodiment> Fig. 10 is a view showing a water treatment device 204 according to a fourth embodiment of the present invention. The water treatment device 204 has an EDI device 104 and an EDI device 101. The small desalting compartment 23d-1 of the EDI device 104, the small desalting compartment 23d-2 of the EDI apparatus 104, and the desalting compartment 23a of the EDI apparatus 101 are sequentially connected in series. The water to be treated flows in from the small desalting chamber 23d-1. The supply water is supplied between the EDI device 104 and the EDI device 101 while the concentrating chambers are not connected in series. The supply water is supplied to the electrode chamber (cathode chamber, anode chamber) of the EDI device 104 and the electrode chamber (cathode chamber, anode chamber) of the EDI device 101, respectively.

Next, the water treatment performed in the small demineralization chambers 23d-1 and 23d-2 of the water treatment apparatus 204 and the desalination chamber 23a will be described. In the EDI devices 104 and 101, a small desalting by the EDI device 104 is performed in a state where supply water is supplied to the anode chamber 21, the concentrating chambers 22 and 24, and the cathode chamber 25, and a direct current voltage is applied between the anode 11 and the cathode 12. The chamber 23d-1 is supplied with treated water.

In the small desalting compartment 23d-1 of the EDI apparatus 104, the same processing as that of the treatment using the anion exchanger AER filled in the inlet side 23b1 region of the demineralization chamber 23b of the first embodiment is estimated. The water to be treated which flows out of the small desalination chamber 23d-1 flows into the small desalting compartment 23d-2. In the small demineralization chamber 23d-2, the same treatment as that performed by using the cation exchanger CER filled in the outlet side 23b2 region of the demineralization chamber 23b of the first embodiment is estimated. The water to be treated which flows out of the small desalination chamber 23d-2 flows into the desalting compartment 23a of the EDI apparatus 101. In the EDI apparatus 101, the same processing as that performed by using the anion exchanger AER filled in the outlet side 23c2 region of the demineralization chamber 23c of the first embodiment is estimated.

Therefore, similarly to the first embodiment, the boron (anion) adsorption efficiency of the anion exchanger AER filled in the desalination chamber 23a is improved, and the boron in the treated water flowing out of the desalination chamber 23a can be made low in concentration.

<Fifth Embodiment> Fig. 11 is a view showing a water treatment device 205 according to a fifth embodiment of the present invention. The water treatment device 205 has an EDI device 101 and an EDI device 105. The desalting compartment 23a of the EDI device 101, the small desalting compartment 23e-2 of the EDI apparatus 105, and the small desalting compartment 23e-1 of the EDI apparatus 105 are connected in series in series. The water to be treated flows in from the desalination chamber 23a. The supply water is supplied between the EDI device 101 and the EDI device 105 while the concentrating chambers are not connected in series. The supply water is supplied to the electrode chamber (cathode chamber, anode chamber) of the EDI device 101 and the electrode chamber (cathode chamber, anode chamber) of the EDI device 105, respectively.

Next, the water treatment performed in the desalination chamber 23a and the small desalination chambers 23e-2 and 23e-1 of the water treatment device 205 will be described. In the EDI devices 101 and 105, the desalination chamber of the EDI device 101 is opened while supplying the supply water to the anode chamber 21, the concentrating chambers 22 and 24, and the cathode chamber 25 and applying a direct current voltage between the anode 11 and the cathode 12. 23a is passed into the treated water.

In the small demineralization chamber 23a of the EDI apparatus 101, the same treatment as that performed by using the anion exchanger AER filled in the inlet side 23b1 region of the demineralization chamber 23b of the first embodiment is estimated. The water to be treated which flows out of the desalination chamber 23a flows into the small desalination chamber 23e-2 of the EDI unit 105.

In the small demineralization chamber 23e-2, the same treatment as that performed by using the cation exchanger CER filled in the inlet side 23c1 region of the demineralization chamber 23c of the first embodiment is estimated. The water to be treated which flows out of the small desalination chamber 23e-2 flows into the small desalting compartment 23e-1. In the small demineralization chamber 23e-1, the same treatment as that performed by using the anion exchanger AER filled in the outlet side 23c2 region of the demineralization chamber 23c of the first embodiment is estimated.

Therefore, similarly to the first embodiment, the boron (anion) adsorption efficiency of the anion exchanger AER filled in the small deionization chamber 23e-1 is improved. Therefore, the boron in the treated water flowing out of the small desalting compartment 23e-1 can be made low in concentration.

Sixth Embodiment FIG. 12 is a view showing a water treatment device 206 according to a sixth embodiment of the present invention. The water treatment device 206 has an EDI device 106 and an EDI device 101. The small desalting compartment 23f-1 of the EDI device 106, the small desalting compartment 23f-2 of the EDI apparatus 106, and the desalting compartment 23a of the EDI apparatus 101 are sequentially connected in series. The water to be treated flows in from the small desalting chamber 23f-1. The supply water is supplied between the EDI device 106 and the EDI device 101 while the concentrating chambers are not connected in series. The supply water is supplied to the electrode chamber (cathode chamber, anode chamber) of the EDI device 106 and the electrode chamber (cathode chamber, anode chamber) of the EDI device 101, respectively.

Next, the water treatment performed in the small demineralization chambers 23f-1 and 23f-2 of the water treatment device 206 and the desalination chamber 23a will be described. In the EDI devices 106 and 101, a small desalting by the EDI device 106 is performed in a state where supply water is supplied to the anode chamber 21, the concentrating chambers 22 and 24, and the cathode chamber 25, and a direct current voltage is applied between the anode 11 and the cathode 12. The chamber 23f-1 is supplied with treated water.

In the small desalination chamber 23f-1 of the EDI apparatus 106, the same treatment as that performed by using the anion exchanger AER filled in the inlet side 23b1 region of the demineralization chamber 23b of the first embodiment is estimated. The water to be treated which flows out of the small desalination chamber 23f-1 is supplied to the small desalting compartment 23f-2 from the inlet side 23f-21 of the small desalting compartment 23f-2 (portion of the packed cation exchanger CER). In the region where the cation exchanger CER is filled in the inlet side 23f-21 of the small demineralization chamber 23f-2, it is estimated that the treatment is performed with the cation exchanger CER which is filled in the outlet side 23b2 region of the demineralization chamber 23b of the first embodiment. The same processing. The water to be treated which is filled in the region of the cation exchanger CER by the small demineralization chamber 23f-2 is supplied to the portion of the small desalting compartment 23f-2 which is filled with the anion exchanger AER. In the portion in which the anion exchanger AER is filled in the small demineralization chamber 23f-2, the same treatment as that in the treatment using the anion exchanger AER in the region of the outlet side 23c2 of the demineralization chamber 23c of the first embodiment is estimated.

The water to be treated which fills the region of the anion exchanger AER through the small desalting compartment 23f-2 is supplied to the desalting compartment 23a of the EDI apparatus 101. In the desalination chamber 23a, the same treatment as that performed by using the anion exchanger AER filled in the outlet side 23c2 region of the demineralization chamber 23c of the first embodiment is estimated.

Therefore, similarly to the first embodiment, the boron (anion) adsorption efficiency of the anion exchanger AER filled in the desalination chamber 23a is improved. Therefore, the boron in the treated water flowing out of the desalination chamber 23a can be made low in concentration.

<Seventh embodiment> Fig. 13 is a view showing a water treatment device 207 according to a seventh embodiment of the present invention. The water treatment device 207 has two EDI devices 106. Hereinafter, the EDI device 106 to which the water to be treated is first introduced is referred to as "first segment EDI device 106-1", and the EDI device 106 to which the treated water is finally passed is referred to as "final segment EDI device 106-2".

The small desalting chamber 23f-1 of the first segment EDI device 106-1, the small desalting chamber 23f-2 of the first segment EDI device 106-1, the small desalting chamber 23f-1 of the final segment EDI device 106-2, and the final segment The small desalting compartments 23f-2 of the EDI device 106-2 are connected in series in series. The water to be treated flows in from the small desalination chamber 23f-1 of the first stage EDI device 106-1. The supply water is supplied between the first stage EDI device 106-1 and the final stage EDI device 106-2 while the concentrating chambers are not connected in series. The supply water is supplied to the electrode chamber (cathode chamber, anode chamber) of the first stage EDI device 106-1 and the electrode chamber (cathode chamber, anode chamber) of the final stage EDI device 106-2, respectively.

Next, the water treatment performed in each desalination chamber of the water treatment device 207 will be described. In the first stage EDI device 106-1 and the final stage EDI device 106-2, supply water is supplied to the anode chamber 21, the concentrating chambers 22 and 24, and the cathode chamber 25, and a direct current voltage is applied between the anode 11 and the cathode 12. In the state, the treated water is introduced into the small desalination chamber 23f-1 of the first stage EDI device 106-1.

In the first stage EDI device 106-1, the same processing as that of the EDI device 106 (see Fig. 12) according to the sixth embodiment is estimated. The treated water flowing out of the first stage EDI unit 106-1 passes into the small desalting chamber 23f-1 of the final stage EDI unit 106-2. In the final stage EDI device 106-2, the processed water flowing out from the first stage EDI device 106-1 is estimated to be processed in the same manner as the processing by the EDI device 106 (see FIG. 12) according to the sixth embodiment. .

Therefore, the boron (anion) adsorption efficiency of the anion exchanger AER filled in the small demineralization chamber 23f-2 of the final stage EDI unit 106-2 is improved, and the small desalination chamber 23f-2 of the final stage EDI unit 106-2 can be discharged. The boron in the treated water is low in concentration.

<Eighth Embodiment> Fig. 14 is a view showing a water treatment device 208 according to an eighth embodiment of the present invention. The water treatment device 208 has an EDI device 106 and an EDI device 105. The small desalting compartment 23f-1 of the EDI device 106, the small desalting compartment 23f-2 of the EDI apparatus 106, the small desalting compartment 23e-2 of the EDI apparatus 105, and the small desalting compartment 23e-1 of the EDI apparatus 105 are sequentially connected in series. The water to be treated flows in from the small desalting chamber 23f-1. The supply water is supplied between the EDI device 106 and the EDI device 105 while the concentrating chambers are not connected in series. The supply water is supplied to the electrode chamber (cathode chamber, anode chamber) of the EDI device 106 and the electrode chamber (cathode chamber, anode chamber) of the EDI device 105, respectively.

Next, the water treatment performed in each desalination chamber of the water treatment device 208 will be described. In the EDI devices 106 and 105, a small desalting by the EDI device 106 is performed in a state where supply water is supplied to the anode chamber 21, the concentrating chambers 22 and 24, and the cathode chamber 25, and a direct current voltage is applied between the anode 11 and the cathode 12. The chamber 23f-1 is supplied with treated water.

In the EDI device 106, the same processing as that of the EDI device 106 (see FIG. 12) according to the sixth embodiment is estimated. The treated water flowing out of the EDI device 106 is passed to the small desalting compartment 23e-2 of the EDI device 105. In the EDI device 105, the same processing as that of the EDI device 105 (see FIG. 11) according to the fifth embodiment is estimated.

Therefore, the boron (anion) adsorption efficiency of the anion exchanger AER filled in the small demineralization chamber 23e-1 of the final stage EDI apparatus 105 is improved, and the boron in the treated water flowing out of the small demineralization chamber 23e-1 can be made low in concentration.

In the respective embodiments described above, the illustrated configuration is only an example, and the present invention is not limited to this configuration. For example, in each of the above embodiments, a water treatment apparatus using two EDI devices can be used. However, in most of the desalination chambers, the anion exchanger is separately filled in the most upstream portion of the first stage desalination chamber into which the treated water is initially introduced and the most downstream portion of the final stage desalination chamber in which the treated water is discharged, and at least one cation The exchange body is filled in a part of a plurality of desalination chambers connected in series, that is, a portion between the most upstream portion of the first stage desalination chamber and the most downstream portion of the final stage desalination chamber, and the number of EDI devices is not limited to two. It can also be 3 or more.

Further, in each of the embodiments, a [concentrating chamber (C) │ anion exchange membrane (AEM) │ desalting compartment (D) │ cation exchange membrane (CEM) │ concentrating compartment (C) is disposed between the anode and the cathode. The basic structure (unit group). However, a plurality of such unit groups may be juxtaposed between the electrodes, and a plurality of unit groups may be electrically connected in series with one end as an anode and the other end as a cathode to increase the processing capability.

In this case, adjacent concentrating compartments may be shared between adjacent unit groups. Therefore, the structure of the EDI device can also be configured using [anode chamber │ C │ AEM │ D │ CEM │ C │ AEM │ D │ CEM │ C │ AEM │ D │ C EM │ │ │ C │ The number of desalination chambers in the EDI device thus connected in series is also referred to as "the number of log units of the desalination chamber".

In such a series configuration, the desalting chamber closest to the anode chamber has a function as a concentrating chamber, and the desalting chamber closest to the cathode chamber, even if it is not interposed between the anode chamber and the concentrating chamber. There is no separate concentrating chamber between the cathode chamber and the cathode chamber, and the cathode chamber itself can also function as a concentrating chamber. In order to reduce the power consumed by the application of the DC voltage, at least one of the concentration chamber, the anode chamber and the cathode chamber may be filled with an ion exchanger to reduce the resistance of the EDI device.

In each of the embodiments, pure water is used as the supply water flowing into the anode chamber from the cathode chamber, but the supply water supplied to the cathode chamber or the anode chamber may not be pure water, and may be, for example, treated water. In addition, the cathode chamber and the anode chamber in the same EDI device may be unconnected or connected in parallel.

In each of the embodiments, pure water is supplied to each of the concentrating chambers, but the treated water output from the EDI device of the second stage may be supplied instead of the pure water. In addition, the processing water outputted by the EDI device of the second stage can also be supplied to each concentration chamber of the EDI unit of the second stage, and the water discharged from each concentration chamber of the EDI unit of the second stage can also be supplied to the first stage. Each concentrating compartment of the EDI device. Further, the water to be treated may be supplied to each concentration chamber of the EDI device of the first stage. [Examples]

Next, examples and comparative examples of the present invention will be described. EXAMPLES AND COMPARATIVE EXAMPLES A water treatment apparatus having two EDI devices and connecting the desalination chambers of the respective EDI devices in series was used. Hereinafter, among the two EDI devices, the EDI device into which the treated water is first introduced is referred to as a "first segment EDI device", and an EDI device that passes the treated water flowing out from the first segment EDI device (final segment EDI device) ) is called the "second stage EDI device".

<Examples 1 to 8> The water treatment apparatuses of Examples 1 to 8 used the water treatment apparatuses 201 to 208 of the first to eighth embodiments shown in Figs. 7 to 14 (please refer to Fig. 20). Next, the EDI device 301 used in the comparative example will be described. Figure 15 is a diagram showing the EDI device 301. The EDI apparatus 301 uses an EDI apparatus that fills the anion exchanger A and the anion exchanger K in a mixed bed form in the desalination chamber 23g.

Next, the water treatment apparatuses of Comparative Examples 1 to 4 will be described. 16 to 19 are views showing the water treatment apparatuses of Comparative Examples 1 to 4, respectively. In Comparative Example 1, the EDI device 301 was used as the first segment EDI device and the second segment EDI device as shown in FIG. In Comparative Example 2, the EDI device 301 was used as the first segment EDI device and the EDI device 103 was used as the second segment EDI device as shown in FIG. In Comparative Example 3, the EDI device 301 was used as the first segment EDI device and the EDI device 102 was used as the second segment EDI device as shown in FIG. In Comparative Example 4, the EDI device 101 was used as the first segment EDI device and the EDI device 301 was used as the second segment EDI device as shown in FIG.

The operating conditions of the specifications, water flow rate, applied current, and water quality of the water to be treated in the examples 1 to 8 and the comparative examples 1 to 4 are as follows. - Anion exchange resin [trade name: AMBERJET (registered trademark) 4002 (strongly basic anion exchange resin 4002), manufactured by Dow Chemical Co., Ltd.] is used as an anion exchanger, and a cation exchange resin is used. [trade name: AMBERJET (registered trademark) 1020 (Strong acid cation exchange resin 1020), manufactured by Dow Chemical Co., Ltd., as a cation exchanger. The volume ratio of the anion exchange resin to the cation exchange resin in the desalting compartments 23b and 23c, the small demineralization chamber 23f-2, and the desalting compartment 23g filled with the anion exchange resin and the cation exchange resin was 1:1.・The volume of the unit (desalting chamber, concentrating chamber, anode chamber, cathode chamber) is 100mm ́100mm ́10mm.・The logarithm of the desalination chamber unit is 1 unit pair.・Water was treated with two stages of RO (reverse osmosis membrane) (conductivity: 3 to 4 μS/cm, boron concentration: 90 to 100 μg B/L) as treated water to the first stage EDI unit.・The treated water flow rate is 20L/h.・The current flowing between the anode and the cathode is 0.4A.・Use pure water from another system as the supply water supplied to the concentrating chamber.・The supply water flow rate supplied to the concentrating chamber is 5 L/h. • Pure water from another system is used as the supply water supplied to the anode chamber and the supply water supplied to the cathode chamber. The supply water flow rate supplied to the anode chamber and the supply water flow rate supplied to the cathode chamber were 5 L/h.

Fig. 20 is a graph showing the measurement results of boron concentration (unit: ngB/L) of the treated waters in Examples 1 to 8 and Comparative Examples 1 to 4. The state of the desalting compartment (filling form of an anion exchange resin, a cation exchange resin, etc.) of each EDI apparatus is shown typically in FIG. In Fig. 20, the anion exchange resin layer is indicated by "A", the cation exchange resin layer is indicated by "K", and the mixed layer of the anion exchange resin and the cation exchange resin is shown as "MB".

From the boron concentrations of the treated waters of Examples 1 to 8 and Comparative Examples 1 to 4, it was found that the boron concentration was not more than 50 ngB/L or less in the desalination chamber of the two EDI devices. Further, it is preferable to make the boron concentration 50 ngB/L or less in pure water used in, for example, a semiconductor process.

On the other hand, as in Embodiments 1 to 8, the region of the most upstream portion of the desalination chamber of the first stage EDI apparatus is separately filled with the anion exchange resin, and the most downstream portion of the desalination chamber of the second stage (final stage) EDI apparatus The region is separately filled with an anion exchange resin, and a portion interposed therebetween is filled with a cation exchange resin, whereby the boron concentration can be made 50 ngB/L or less.

Comparing Example 1 with Examples 2 and 3, and Comparative Examples 1 to 3 with Comparative Example 4, it is known that the anion exchange resin is filled in a single bed form in the desalting chamber of the first stage EDI apparatus, or in the second stage. The desalting compartment of the EDI apparatus fills the anion exchange resin in a single bed form, whereby the boron concentration of the treated water can be further reduced.

From the comparison of Examples 2 to 3 and Examples 4 to 5, it is understood that at least one of the desalination chambers connected in series has a desalting chamber having an intermediate ion exchange membrane, a first small desalting compartment, and a second small desalting compartment ( Hereinafter, it is referred to as "D2 desalting compartment"), whereby the boron concentration of the treated water can be further reduced. However, when the D2 desalting chambers are connected in series, the water pressure difference may rise. Therefore, if the number of D2 desalination chambers is increased to a necessary number or more as in Examples 4 to 6, the boron concentration of the treated water can be made lower than the target value (for example, 50 ng B/L), and the water pressure difference is advantageous.

From the comparison between Example 7 and Example 8, it is understood that the boron concentration of the treated water can be further reduced by filling the anion exchange resin in a single bed form in the desalting compartment of the smallest portion of the final stage (second stage) EDI apparatus.

<Examples 9 to 10> Next, the water treatment apparatuses of Examples 9 to 10 will be described with reference to Fig. 21 . In the first embodiment, in the state in which the volume ratio of the cation exchange resin to the anion exchange resin in the deionization chamber of the second stage EDI apparatus is constant (cation exchange resin: anion exchange resin = 9:1), the change is made. An example of the volume ratio of the anion exchange resin to the cation exchange resin in the desalting compartment of the first stage EDI apparatus (the volume ratio of the anion exchange resin is changed between 5% and 100%).

In the first embodiment, in the first embodiment, the volume ratio of the anion exchange resin to the cation exchange resin in the deionization chamber of the first stage EDI apparatus is constant (anion exchange resin: cation exchange resin = 1:9), and is changed. An example of the volume ratio of the cation exchange resin to the anion exchange resin in the desalting compartment of the second stage EDI apparatus (the volume ratio of the anion exchange resin is changed between 5% and 100%).

Fig. 21 is a graph showing the results of measurement of the boron concentration of the treated water in Examples 9 to 10. In addition, the state of the desalination chamber of each EDI apparatus (filled state of an anion exchange resin and a cation exchange resin, etc.) is shown in FIG. 21, and an anion exchange resin is shown by "A" or "AER", and is represented by "K". Cation exchange resin.

In Fig. 21, the measurement result of the embodiment 9 is such that the boron concentration of the treated water when the ratio of the anion exchange resin of the first stage EDI apparatus is 5% is "1", and the treatment when the ratio of the anion exchange resin is increased is drawn. The degree of reduction in boron concentration of water is taken as the removal ratio. On the other hand, in the measurement result of Example 10, the boron concentration of the treated water when the ratio of the anion exchange resin of the second stage EDI apparatus was 5% was "1", and the treated water when the ratio of the anion exchange resin was increased was drawn. The degree of reduction in boron concentration is taken as the removal ratio. In Examples 9 and 10, the water passing test was carried out under the same water supply load conditions as in Examples 1 to 8 and Comparative Examples 1 to 4 (for example, two stages of RO permeated water were used as the treated water, and the first stage EDI device was introduced. The treated water in the desalting compartment has a boron concentration of 90 to 100 μg B/L).

It can be seen from Examples 9 and 10 that the higher the ratio of the anion exchange resin, the lower the boron concentration of the treated water. Further, in the case of comparing the ratio of the anion exchange resin to 5% and 10%, it was confirmed that the degree of decrease in the boron concentration of the treated water was remarkably large at 10% or less. This means that the ratio of the volume of the anion exchanger filled in the most upstream portion of the first stage of the desalination chamber to the volume of the first stage of the desalting chamber and the volume of the anion exchanger separately filled in the most downstream portion of the final stage of the desalting chamber are the final stage of the desalting chamber. When the volume ratio is 10% or more, the degree of reduction in the boron concentration of the treated water is remarkably large.

Further, in the case where the ratio of the anion exchange resin is 50% or more, when the ratio of 10 to less than 50% is compared, it is confirmed that the effect of reducing the boron concentration of the treated water is large. This means that the ratio of the volume of the anion exchanger filled in the most upstream portion of the first stage of the desalination chamber to the volume of the first stage of the desalting chamber and the volume of the anion exchanger separately filled in the most downstream portion of the final stage of the desalting chamber are the final stage of the desalting chamber. When the volume ratio is 50% or more, the degree of reduction in the boron concentration of the treated water is remarkably large.

<Examples 11 to 13> Next, water treatment apparatuses of Examples 11 to 13 will be described with reference to Fig. 22 . Embodiment 11 is the first embodiment in which the concentration of cerium oxide and boron is fixed at a level of 100 micrograms per liter with respect to the water to be treated which is introduced into the desalting compartment in the first stage EDI apparatus (cerium oxide: An example of changing the concentration of carbonic acid (mgCO ₂ /L) in a state of 98 μg SiO ₂ /L or boron: 97 μg B/L).

Embodiment 12 is the first embodiment in which the concentration of boron and carbonic acid is constant for the water to be treated which is introduced into the desalination chamber in the first stage EDI apparatus (boron: 97 μg B/L, carbonic acid: 5 mg CO ₂ /L) In the state of the cerium oxide, the concentration of cerium oxide (μg SiO ₂ /L) is changed.

In the first embodiment, in the case of the treated water which is introduced into the demineralization chamber in the first stage EDI apparatus, the concentration of the cerium oxide and the carbonic acid is made constant (cerium oxide: 98 μg SiO ₂ /L, carbonic acid: An example of changing the concentration of boron (μg B/L) in the state of 5 mg CO ₂ /L).

Fig. 22 is a graph showing the results of measurement of the boron concentration of the treated water in Examples 11 to 13. In Fig. 22, an anion exchange resin is indicated by "A", and a cation exchange resin is indicated by "K".

It can be confirmed from Examples 11 to 13 that the concentration of carbonic acid in the water to be treated which is introduced into the desalting compartment of the first stage EDI apparatus is 5 mg CO ₂ /L or less, the concentration of cerium oxide is 100 μg SiO ₂ /L or less, and the boron concentration is 100 μg B/L. In the following, the boron concentration of the treated water is 50 ngB/L or less.

Further, in the thirteenth embodiment, when the boron concentration of the treated water supplied to the deionization chamber of the first stage EDI apparatus is about 200 (198) μg B/L, the current flowing between the anode and the cathode is 0.8 A, and then the test is performed. As a result, the boron concentration of the treated water could not be made 50 ngB/L or less. Therefore, it was confirmed that simply increasing the current value did not make the boron concentration of the treated water 50 ngB/L or less.

<Example 14> Next, a water treatment apparatus of Example 14 will be described with reference to Fig. 23 . In the embodiment 8, in the case of the treated water which is introduced into the small demineralization chamber 23f-1 in the first stage EDI apparatus, the concentration of the cerium oxide and the carbonic acid is made constant (cerium oxide: 101 μg SiO ₂ / In the state of L, carbonic acid: 5 mg CO ₂ /L), the boron concentration (μg B/L) is changed.

Fig. 23 is a graph showing the measurement results of the boron concentration of the treated water in Example 14. In Fig. 23, an anion exchange resin is indicated by "A", and a cation exchange resin is indicated by "K".

In the case of the deionization chambers (hereinafter referred to as "D1 desalting chambers" which are not separated by the intermediate ion exchange membrane, the boron concentration of the treated water is 50 ngB/L or less, as long as the access is made. The boron concentration of the water to be treated in one piece of the EDI device may be 100 μg B/L or less.

However, as shown in Examples 4 to 8, the boron concentration of the treated water can be reduced in the water treatment apparatus by increasing the EDI apparatus having the D2 desalination chamber. In this regard, it was confirmed that in Example 14, even if the boron concentration of the water to be treated which passed through the first stage EDI apparatus was higher than the boron concentration of the water to be treated in Example 13 by about 300 (298) μg B/L, The boron concentration of the treated water can be made 50 ngB/L or less.

Here, the reason why the anion exchange resin is separately filled in the most upstream portion of the desalination chamber that is connected in series will be described. The boron in the water to be treated can promote dissociation of the anion when it contacts the anion exchange resin of the solid base, and as a result, the adsorption removal efficiency of the anion exchange resin becomes good.

Next, the reason why the anion exchange resin is separately filled in the most downstream portion of the deionization chamber that is connected in series, and at least the cation exchange resin is filled between the most upstream portion and the most downstream portion will be described. In the case where the treated water is introduced into the most downstream portion of the anion exchange resin without using the cation exchange resin to remove the cationic component, the cation exchange resin is used to remove the cationic component in the treated water, and the treated water is passed to the most downstream. The anion exchange resin of the portion can reduce the concentration of hydroxide ions in the water to be treated in which the anion exchange resin that has passed through the most downstream portion is present, so that the boron removal efficiency using the anion exchange resin is improved.

Further, in the second small demineralization chamber of the final stage of Example 7, since the ion exchange resin was formed in a multi-bed form (the form in which the anion exchange resin and the cation exchange resin were separately filled), the current flowing through the second small deionization chamber was biased. This bias flow is caused by a difference in electrical resistance between the anion exchange resin and the cation exchange resin, and a phenomenon in which a large electric current flows in the anion exchange resin and the cation exchange resin. On the other hand, in the second small deionization chamber of the final stage of Example 8, the anion exchange resin was filled in a single bed form, so that the bias flow was less likely to occur than in Example 7, and the removal efficiency of boron was improved.

Next, the advantages of using the D2 desalting chamber will be explained. As described above, current is biased in the desalination chamber in a multi-bed form. Therefore, the anion exchange resin and the cation exchange resin can be filled in a single bed form in the two small desalting chambers of the D2 desalting compartment, respectively, by filling the anion exchange resin and the cation exchange resin in a multi-bed form in one desalination chamber. The current flows more efficiently into the anion exchange resin, so the desalination efficiency becomes better. However, compared with the D1 desalination chamber, since the flow path length of the D2 desalination chamber is about twice as large, there is a fear that the water pressure difference becomes high. Therefore, by reducing the number of EDI devices using the D2 desalination chamber within a range in which the target boron concentration in the treated water can be achieved, the increase in the water pressure difference can be reduced.

Here, the "most upstream portion of the desalination chamber" refers to the (predetermined) portion that is first passed when the treated water flows into the desalination chamber, and the "most downstream portion of the desalting chamber" refers to when the treated water flows out from the desalting chamber to the outside. Finally pass the (certain) part. The "most upstream portion of the desalination chamber" and the "most downstream portion of the desalination chamber" do not necessarily refer to the physical relationship, for example, if the water to be treated flows from the upper side of the desalting chamber, and then flows out from the lower side of the desalting chamber. The situation.

11‧‧‧Anode
12‧‧‧ cathode
21‧‧‧Anode chamber
22‧‧‧Concentration room
23a~23f‧‧‧Desalting room
23b1‧‧‧ entrance side
23b2‧‧‧Exit side
23c1‧‧‧ entrance side
23c2‧‧‧Exit side
23d-1‧‧‧First small desalination room
23d-2‧‧‧Second small desalination room
23e-1‧‧‧First small desalination room
23e-2‧‧‧Second small desalination room
23f-1‧‧‧First small desalination room
23f-2‧‧‧Second small desalination room
23f-21‧‧‧ entrance side
23f-22‧‧‧Exit side
23g‧‧‧Desalting room
24‧‧‧Concentration room
25‧‧‧Cathode chamber
31‧‧‧Cation exchange membrane
32‧‧‧ anion exchange membrane
33‧‧‧Cation exchange membrane
34‧‧‧ anion exchange membrane
36‧‧‧Intermediate ion exchange membrane
101~106‧‧‧EDI device
104a‧‧‧Arrow
104b‧‧‧Arrow
104c‧‧‧Arrow
105a‧‧‧Arrow
105b‧‧‧Arrow
105c‧‧‧Arrow
106a‧‧‧Arrow
106b‧‧‧Arrow
106c‧‧‧Arrow
106-1‧‧‧First paragraph EDI device
106-2‧‧‧ final stage EDI device
111‧‧‧ reverse osmosis membrane device
112‧‧‧Decarbonated membrane device
201~208‧‧‧Water treatment device
301‧‧‧EDI device
A‧‧‧ anion exchange resin layer
AER‧‧‧ anion exchanger
CER‧‧‧ cation exchanger
K‧‧‧Cation exchange resin layer
Mixed layer of MB‧‧ anion exchange resin and cation exchange resin

Fig. 1 is a view showing an EDI device 101 of a first aspect. FIG. 2 is a diagram showing the EDI device 102 of the second aspect. Fig. 3 is a view showing the EDI device 103 of the third aspect. FIG. 4 is a view showing the EDI device 104 of the fourth aspect. Fig. 5 is a view showing the EDI device 105 of the fifth aspect. Fig. 6 is a view showing the EDI device 106 of the sixth aspect. Fig. 7 is a view showing a water treatment device 201 according to the first embodiment of the present invention. Fig. 8 is a view showing a water treatment device 202 according to a second embodiment of the present invention. Fig. 9 is a view showing a water treatment device 203 according to a third embodiment of the present invention. Fig. 10 is a view showing a water treatment device 204 according to a fourth embodiment of the present invention. Fig. 11 is a view showing a water treatment device 205 according to a fifth embodiment of the present invention. Fig. 12 is a view showing a water treatment device 206 according to a sixth embodiment of the present invention. Fig. 13 is a view showing a water treatment device 207 according to a seventh embodiment of the present invention. Fig. 14 is a view showing a water treatment device 208 according to an eighth embodiment of the present invention. Fig. 15 is a view showing the EDI device 301. Fig. 16 is a view showing a water treatment apparatus of Comparative Example 1. Fig. 17 is a view showing a water treatment apparatus of Comparative Example 2. Fig. 18 is a view showing a water treatment apparatus of Comparative Example 3. Fig. 19 is a view showing a water treatment apparatus of Comparative Example 4. Fig. 20 is a graph showing the results of measurement of boron concentration of the treated waters in Examples 1 to 8 and Comparative Examples 1 to 4. Fig. 21 is a graph showing the results of measurement of boron concentration of the treated water of Examples 9 to 10. Fig. 22 is a graph showing the results of measurement of boron concentration of the treated water in Examples 11 to 13. Fig. 23 is a graph showing the measurement results of boron concentration of the treated water in Example 14.

11‧‧‧Anode

12‧‧‧ cathode

21‧‧‧Anode chamber

22‧‧‧Concentration room

23b, 23c‧‧‧Desalting room

23b1, 23c1‧‧‧ entrance side

23b2, 23c2‧‧‧ exit side

24‧‧‧Concentration room

25‧‧‧Cathode chamber

31‧‧‧Cation exchange membrane

32‧‧‧ anion exchange membrane

33‧‧‧Cation exchange membrane

34‧‧‧ anion exchange membrane

102, 103‧‧‧EDI device

111‧‧‧ reverse osmosis membrane device

112‧‧‧Decarbonated membrane device

201‧‧‧Water treatment unit

AER‧‧‧ anion exchanger

CER‧‧‧ cation exchanger

Claims (14)

A water treatment device having a plurality of electrical deionized water production devices, wherein: each of the electric deionized water production devices of the electric deionized water production device has a desalination chamber between the anode and the cathode. The desalting compartment is partitioned by an anion exchange membrane located on the anode side and a cation exchange membrane located on the cathode side, and filled with an ion exchanger, each of the desalination chambers in the majority of the electric deionized water production apparatus The plurality of desalination chambers connected in series are connected to the treated water and flow out the treated water, and the most upstream portion of the demineralization chamber of the first stage in which the treated water is initially introduced, and the treated water is discharged. The most downstream portion of the desalting chamber in the final stage is separately filled with an anion exchanger, and a part of the plurality of desalting chambers is located at the most upstream portion of the first stage desalination chamber and the most downstream portion of the final stage desalination chamber A portion between the two is filled with at least a cation exchanger. The water treatment device according to claim 1, wherein "the volume of the anion exchanger filled in the most upstream portion of the first-stage demineralization chamber" is proportional to the "volume of the first-stage demineralization chamber", and " The ratio of the volume of the anion exchanger filled in the most downstream portion of the final stage desalination chamber to the "the final stage desalination chamber volume" is 10% or more. The water treatment device according to claim 1 or 2, wherein the anion exchanger is filled in a single bed form in the first stage desalination chamber or the final stage desalination chamber. The water treatment device of claim 1 or 2, wherein at least one of the plurality of desalting chambers has: an intermediate ion exchange membrane between the anion exchange membrane and the cation exchange membrane; a small desalting compartment separated from the intermediate ion exchange membrane by the anion exchange membrane; and a second small desalting compartment separated from the intermediate ion exchange membrane by the cation exchange membrane, the first small desalting compartment and The second small desalting chamber is connected in series. The water treatment device of claim 4, wherein the first stage deionization chamber has the intermediate ion exchange membrane, the first small desalting compartment and the second small desalting compartment, in the first section of the desalting compartment, The first small desalting compartment is located on the upstream side of the second small desalting compartment, and the anion exchanger is filled in a single bed form in the first small desalting compartment. The water treatment device of claim 4, wherein the final stage desalination chamber has the intermediate ion exchange membrane, the first small desalting chamber, and the second small desalting chamber, and in the final section desalination chamber, the first A small desalting chamber is located on the downstream side of the second small desalting chamber, and the anion exchanger is filled in a single bed form in the first small desalting chamber. The water treatment device of claim 4, wherein two or more of the electric deionized water producing devices are provided, wherein the first stage and the final stage desalination chamber respectively have the intermediate ion exchange membrane, the first a small demineralization chamber and the second small desalting chamber, wherein in the first stage and the final stage demineralization chamber, the first small desalting chamber is located on an upstream side of the second small desalting chamber, and the first small desalting chamber is in a single The bed form is filled with an anion exchanger, and a cation exchanger is separately filled in the most upstream portion of the second small desalting chamber, and an anion exchanger is separately filled in a portion other than the most upstream portion of the second small desalting chamber. The water treatment device of claim 4, wherein two or more of the electric deionized water producing devices are provided, wherein the first stage and the final stage desalination chamber respectively have the intermediate ion exchange membrane, the first a small desalting chamber and the second small desalting chamber, wherein the first small desalting chamber is located on an upstream side of the second small desalting chamber, and the anion is filled in a single bed form in the first small desalting chamber a exchanger in which a cation exchanger is separately filled at an upstream portion of the second small desalination chamber, and an anion exchanger is separately filled in a portion other than the most upstream portion of the second small desalination chamber, in the final section desalination chamber Wherein the first small desalting compartment is located on the downstream side of the second small desalting compartment, the anion exchanger is filled in a single bed form in the first small desalting compartment, and the cation exchange is filled in a single bed form in the second small desalting compartment body. The water treatment device according to claim 1 or 2, wherein the upstream side of the first stage desalination chamber is provided with a reverse osmosis membrane device. The water treatment device according to claim 1 or 2, wherein the upstream side of the first stage desalination chamber is provided with a decarbonation membrane device. A water treatment method using a water treatment device comprising a plurality of electrically deionized water producing devices having a desalination chamber between an anode and a cathode, the desalination chamber being an anion exchange membrane located on the anode side, And a cation exchange membrane located on the cathode side is partitioned and filled with an ion exchanger, and each of the desalination chambers in the plurality of electric deionized water production apparatuses are connected in series, and the plurality of desalination chambers connected in series are connected Passing in the treated water and flowing out the treated water, and separately at the most upstream portion of the demineralization chamber of the first stage into which the treated water is initially introduced, and the most downstream portion of the demineralization chamber flowing out of the final stage of the treated water Filling an anion exchanger, and at least a portion of the plurality of desalting chambers between the most upstream portion of the first stage desalination chamber and the most downstream portion of the final stage desalination chamber is filled with a cation exchanger, the water treatment method A DC voltage is applied between the anode and the cathode, and the water to be treated is introduced into the plurality of desalting chambers connected in series to process the treated water. The treated water is discharged. The water treatment method according to claim 11, wherein the concentration of cerium oxide of the water to be treated which is introduced into the first-stage electric deionized water producing apparatus is 100 μg SiO ₂ /L or less. The water treatment method according to claim 11 or 12, wherein the boron concentration of the water to be treated which is introduced into the first-stage electric deionized water producing apparatus is 100 μg B/L or less. The water treatment method according to claim 11 or 12, wherein the water to be treated of the first-stage electric deionized water producing apparatus has a carbonic acid concentration of 5 mg CO ₂ /L or less.