JP2003205289A - Denitrification method of water and water treatment equipment used therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method which efficiently performs a series of denitrification process of reducing nitrate ion (nitrite ion) in water by an electrochemical reaction, converting the generated ammonia to nitrogen gas and removing the same from the water, and to provide treatment equipment used for denitrification treatment. <P>SOLUTION: This denitrification method of water is provided with a cathode 20 which, for example, reduces nitrate ion (nitrite ion) by means of electrochemical reaction and an anode 21 which generates chlorine from chloride ion. This denitrification method further features that the water to be treated is introduced into an electrolytic reaction vessel 10 which is partitioned to a cathode reaction region 22 and an anode reaction region 23 by a cation exchange membrane 24, the power is applied to the vessel, thereafter, the treated water is taken out from the cathode reaction region 22 and the anode reaction region 23, new water to be treated and the treated water taken out from the anode reaction region 23 are poured into the cathode reaction region 22, subsequently, the power is applied to the electrolytic reaction vessel 10 and the new water to be treated is subjected to denitrification treatment. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a denitrification treatment method for water and a water treatment apparatus used for the denitrification treatment. More specifically, the present invention relates to a treatment method for removing a nitrogen component dissolved in water to be treated by an electrochemical reaction without using a biological denitrification treatment method, and a water treatment device used for the removal treatment.

[0002]

TECHNICAL FIELD OF THE INVENTION AND PROBLEMS TO BE SOLVED BY THE INVENTION Since nitrogen components such as nitrate ions, nitrite ions, and ammonia dissolved in factory wastewater, domestic wastewater, and groundwater are causative substances of water pollution, It is extremely important to develop a means for removing the nitrogen component. Among the nitrogen components, nitrate ion, as a method for removing oxidized nitrogen such as nitrite ion, conventionally, a biological denitrification method using a denitrifying bacterium is known, a biocatalyst such as the denitrifying bacterium, Since the degree of its activity depends on the temperature, there is a problem that the ability to remove nitrogen components varies greatly depending on the season.

On the other hand, Japanese Patent Application Laid-Open No. 11-347558 discloses a method of removing the nitrogen component by an electrochemical reaction without using a biocatalyst such as a denitrifying bacterium.
In the process of removing the nitrogen component by the electrochemical reaction, the reduction reaction of nitrate ion represented by the following reaction formula (1) occurs at the cathode, and the reactions represented by the following reaction formulas (2) and (3) occur at the anode. The following reaction formula (4) is a formula showing that nitrogen gas is generated and volatilized by the reaction between ammonia generated at the cathode and hypochlorous acid generated at the anode.

[0004]

[Chemical 1]

The apparatus for denitrifying the water to be treated utilizing such an electrochemical reaction does not have the problem that the ability of removing nitrogen components varies depending on the season as in the biological denitrification method, and the maintenance of the biocatalyst is not required. You don't have to worry about it. However, in the denitrification treatment by the electrochemical reaction, it is necessary to strictly control and adjust the amount of electricity supplied to the electrolytic cell and the amount of electrolyte dissolved in the water to be treated. If these are not adequately controlled and adjusted, the reduction reaction of nitrate ion does not proceed, an excessive current is applied to damage the electrode pair, and the toxicity is higher than that of nitrate ion. This causes a problem that treated water containing a high concentration of ammonia is produced.

Therefore, an object of the present invention is to carry out a series of denitrification treatments in which nitrate ions or nitrite ions of the water to be treated are reduced by an electrochemical reaction, and the produced ammonia is replaced with nitrogen gas and removed from the water to be treated. It is an object of the present invention to provide a method capable of efficiently performing steps and a treatment device used for denitrification treatment of the water.

[0007]

Means for Solving the Problems and Effects of the Invention The first method for denitrifying water according to the present invention for solving the above problems is a cathode for reducing (nitrite) ions by an electrochemical reaction, It is characterized in that after water to be treated and hypochlorous acid (ion) and / or ozone are introduced into an electrolytic reaction tank provided with an anode, the electrolytic reaction tank is energized.

In a series of denitrification treatments in which the (nitrite) ions of the water to be treated are reduced and the produced ammonia is converted to nitrogen gas and volatilized, a large amount of hypochlorous acid ( Ion) is required. In the conventional denitrification treatment method of water by electrochemical reaction, a large amount of electrolyte solution containing chloride ions such as saline solution is injected to increase the chloride ion concentration of the water to be treated, and the following anode reaction during electrolytic treatment is performed. Although a method of generating chlorous acid is adopted, this method not only requires a large amount of electrolyte solution such as saline solution, but also sufficient hypochlorous acid (ion) necessary for denitrification treatment. There is a problem that it is difficult to supply. On the other hand, according to the above first denitrification treatment method of water, since hypochlorous acid and ozone are directly supplied into the electrolytic reaction tank, for example, the (nitrite) ion concentration of the water to be treated is high, Even if the hypochlorous acid (ion) generated by the anode reaction is insufficient, the denitrification treatment of water can be efficiently performed. The ozone introduced into the electrolytic reaction tank causes a reaction of releasing oxygen atoms as shown in the following formula (5), and the oxygen atoms thus released react with ammonia in the water to be treated. As a result, an ammonia oxidative denitrification reaction represented by the following reaction formula (6) occurs, and nitrogen gas is generated. The following reaction formula (7) is a reaction formula of ammonia oxidative denitrification reaction by ozone.

[0009]

[Chemical 2]

In the first denitrification treatment method of water, the anode may produce chlorine from chloride ions by an electrochemical reaction. In this case, the efficiency of denitrification treatment can be further improved.

In the first denitrification treatment method for water and the first water treatment apparatus to be described later, brass, copper, and copper are used for the cathode for reducing (nitrite) ions by an electrochemical reaction.
Examples thereof include a conductor containing a Group 11 or Group 12 element such as zinc, or a conductor coated with a Group 11 or Group 12 element. Among them, brass is suitable for the present invention because it has extremely excellent nitrate ion reducing properties. Also,
The anode that produces chlorine from chloride ions by an electrochemical reaction is not particularly limited. For example, a Group 10 element such as platinum or palladium or ruthenium, iridium or the like is plated or burnt on a titanium base material. Examples include a metal electrode formed by binding, a carbon electrode, a ferrite electrode, and the like. In addition, also in another denitrification treatment method of water and another water treatment apparatus according to the present invention described later, chlorine is generated from chloride ion by a cathode for reducing (nitrite) ion by an electrochemical reaction and electrochemical reaction. The above-mentioned examples are exemplified as the anode.

In the first denitrification treatment method of water, a diaphragm separation type may be used as the electrolytic reaction tank. The denitrification treatment method of water in this case is the same as the first denitrification treatment method of water. It is characterized in that it is divided into a reaction zone and an anode reaction zone, and that the hypochlorous acid (ion) and / or ozone is introduced into the cathode reaction zone.

Thus, the cathode and the anode in the electrolytic reaction tank are separated by the electron permeable membrane which does not allow ammonia and hypochlorous acid (ions) to pass therethrough, so that the ammonia produced at the cathode is placed on the anode. And again (A)
It is possible to prevent the so-called reverse reaction from returning to nitrate ions. Therefore, as a result, the speed of denitrification treatment is increased and the current efficiency is also improved. Further, by connecting a hypochlorous acid supply device and / or an ozone supply device to the cathode reaction zone, it is possible to efficiently perform conversion of ammonia into nitrogen gas.

In the first method for denitrifying water, as a hypochlorous acid supplying means, an electrolytic solution of hypochlorous acid is produced by electrolyzing an electrolyte solution containing chloride ions. A chloric acid generator can be used. In this case, it is preferable to use treated water that has been subjected to a series of denitrification treatment in the electrolytic reaction tank as the electrolyte solution to be introduced into the electrolytic type hypochlorous acid generator. That is, in the case of using the electrolytic hypochlorous acid generator, in the first denitrification treatment method of water, the hypochlorous acid (ion) introduced into the electrolytic reaction tank is the electrolytic hypochlorous acid generator. The electrolytic solution that is produced and is introduced into the electrolytic hypochlorous acid generator is treated water that has been subjected to denitrification treatment in the electrolytic reaction tank.

The treated water obtained by subjecting the water to be treated to the above series of treatments contains chloride ions, hypochlorous acid (ions) not used for denitrification treatment, or electrolysis of water. It contains an electrolyte such as generated hydroxide ions. Therefore, such treated water can be reused as a high-quality hypochlorous acid generation source containing a large amount of electrolyte, thereby reducing the amount of electrolyte solution newly injected during the hypochlorous acid generation treatment. can do.

A first water treatment apparatus for use in the first denitrification treatment method of water according to the present invention for solving the above-mentioned problems comprises a cathode for reducing (nitrite) ions by an electrochemical reaction, and An anode, an electrolytic reaction tank containing the cathode and the anode, a hypochlorous acid supply means and / or an ozone supply means, and a water passage connected from the supply means to the electrolytic reaction tank. Is. By using the first water treatment device, the first denitrification treatment method of water can be easily performed, and the denitrification treatment of water can be efficiently performed.

In the first water treatment device, the anode may generate chlorine from chloride ions by an electrochemical reaction. In this case, the efficiency of denitrification treatment can be further improved. In addition, in the first water treatment device, a membrane separation type may be used as the electrolytic reaction tank. When using a diaphragm-separated electrolytic reaction tank, a membrane that does not permeate ammonia and hypochlorous acid (ions) but permeates electrons is used as a diaphragm that partitions the cathode reaction region and the anode reaction region. Hypochlorous acid (ions) and / or ozone may be introduced into the cathode reaction zone.

Further, in the first water treatment apparatus, as a hypochlorous acid supply means, electrolytic hypochlorous acid is generated by electrolyzing an electrolyte solution containing chloride ions to generate hypochlorous acid. An acid generator can be used. In this case, it is preferable that the electrolytic reaction tank is provided with a water passage for introducing a series of denitrified treated water into the electrolytic hypochlorous acid generator. That is, in the water treatment device using the electrolytic hypochlorous acid generator, in the first water treatment device, the hypochlorous acid supply means generates hypochlorous acid (ions) by an electrochemical reaction. An electrolytic hypochlorous acid generator, the electrolytic reaction tank, a water passage for transferring the treated water denitrified in the electrolytic reaction tank into the electrolytic hypochlorous acid generator It is characterized by being provided. By using the above water treatment device, not only the efficiency of the denitrification treatment but also the efficiency of the hypochlorous acid generation reaction can be improved.

In the above-mentioned water treatment device, when the electrolytic reaction tank is of the membrane separation type, the treated water transferred to the hypochlorous acid generator after the denitrification treatment is in the cathode reaction zone of the electrolytic reaction tank. It is preferably treated. By introducing cathode treated water, treated water rich in electrolyte can be supplied to the hypochlorous acid generator.

A second method for denitrifying water according to the present invention for solving the above-mentioned problems is to produce chlorine from chloride ions by a cathode for reducing (nitrite) ions by an electrochemical reaction and an electrochemical reaction. Introducing water to be treated into an electrolytic reaction tank provided with an anode, further supplying chloride ions to adjust the chloride ion concentration of the water to be treated, and then energizing the electrolytic reaction tank. . In the conventional denitrification treatment method of water by electrochemical reaction, since there is no means for adjusting the chloride ion concentration in the water to be treated, the condition of voltage / current varies depending on the change of conductivity. There is a problem that it changes or the generation efficiency of hypochlorous acid (ions) decreases. On the other hand, according to the second denitrification treatment method of water, the concentration of chloride ions in the water to be treated can be appropriately adjusted, and as a result, hypochlorous acid (ions) generated from the anode is generated. It is possible to improve the generation efficiency of water and increase the conductivity of the water to be treated. Therefore, it is possible to reduce power consumption in a series of denitrification treatments.

A second water treatment apparatus for use in the second method for denitrifying water according to the present invention for solving the above-mentioned problems comprises a cathode for reducing (nitrite) ions by an electrochemical reaction. An anode that produces chlorine from chloride ions by an electrochemical reaction, an electrolytic reaction tank that accommodates the cathode and the anode, and chloride ion supply means that is connected to the electrolytic reaction tank. By using the second water treatment device, the operation of adjusting the chloride ion concentration of the water to be treated can be easily performed in the second method for denitrifying water.
In addition, the conductivity of the water to be treated can be increased, and the power consumption in the series of denitrification treatments can be suppressed.

The second method for denitrifying water and the second method
In the above water treatment device, a membrane separation type may be used as the electrolytic reaction tank. In this case, chloride ions may be set so as to be supplied to the anode reaction region of the electrolytic reaction tank. By using a separable electrolytic reaction tank,
As in the case described above, it is possible to prevent the reverse reaction in the electrolytic reaction tank.

A third method for denitrifying water according to the present invention for solving the above-mentioned problems comprises a first cathode and a first anode which produces chlorine from chloride ions by an electrochemical reaction. After introducing the water to be treated into the first electrolytic reaction tank provided and further supplying chloride ions to adjust the concentration of chloride ions in the water to be treated, the first electrolytic reaction tank is energized and Chloric acid is generated, and then the water to be treated in the first electrolytic reaction tank is subjected to an electrochemical reaction (sub)
Introduced into a second electrolytic reaction tank provided with a second cathode for reducing nitrate ions and a second anode,
It is characterized by energizing the electrolytic reaction tank.

According to the third method of denitrifying water,
Electrolysis reactor for producing nitrogen gas from ammonia (second
Before the water to be treated is introduced into the electrolytic reaction tank (1), the concentration adjustment of chloride ions and the generation treatment of hypochlorous acid (ions) are performed in the electrolytic reaction tank (first electrolytic reaction tank).
Therefore, when the water to be treated is introduced into the second electrolytic reaction tank, a large amount of hypochlorite ion can be already contained in the water to be treated, and the reaction of producing and removing nitrogen gas can be efficiently performed. You can proceed.

In the third method of denitrifying water, a membrane separation type may be used as the electrolytic reaction tank. Here, when a diaphragm separation type is used as the first electrolytic reaction tank, it is set so that chloride ions are supplied to the anode reaction region in the first electrolytic reaction tank. That is, when the diaphragm separation type is used as the first electrolytic reaction tank, the third method for denitrifying water is
The first electrolytic reaction tank is divided into a cathode reaction region and an anode reaction region by an electron permeable membrane that is impermeable to ammonia and hypochlorous acid (ions), and chloride ion Is supplied to the anode reaction region of the first electrolytic reaction tank, and after the first electrolytic reaction tank is energized, the water to be treated in the cathode reaction region and the anode reaction region is added to the second electrolytic reaction tank. It is characterized in that it is introduced into an electrolytic reaction tank. By using a diaphragm-separated type for the first electrolytic reaction tank, the generation efficiency of hypochlorous acid (ions) can be improved.

A third water treatment apparatus for use in the third method for denitrifying water according to the present invention for solving the above-mentioned problems comprises a first cathode and a chloride ion by an electrochemical reaction. A first electrolytic reaction tank accommodating a first anode that generates chlorine, a chloride ion supply means connected to the first electrolytic reaction tank, and (nitrite) ions are reduced by an electrochemical reaction. A second cathode and a second
A second electrolytic reaction tank containing the anode and a water passage connected from the first electrolytic reaction tank to the second electrolytic reaction tank. By using the third water treatment device, it is possible to make the hypochlorite ion concentration of the water to be treated extremely high when the water to be treated is introduced into the second electrolytic reaction tank. Third
The water denitrification treatment method can be easily performed.
Further, the conductivity of the water to be treated in the second electrolytic reaction tank can be increased, and the power consumption in the series of denitrification treatments can be suppressed.

In the third water treatment apparatus, a membrane separation type electrolytic reaction tank may be used. When a diaphragm separation type is used as the first electrolytic reaction tank,
The chloride ion is set to be supplied to the anode reaction zone in the first electrolytic reaction tank. As described above, by using the membrane separation type for the first electrolytic reaction tank, the generation efficiency of hypochlorous acid (ions) can be improved.

A fourth method for denitrifying water according to the present invention for solving the above-mentioned problems is a cathode for reducing (nitrite) ions by an electrochemical reaction and chlorine from chloride ions by an electrochemical reaction. Water to be treated is placed in an electrolytic reaction tank that is equipped with a generating anode and that is permeable to ammonia and hypochlorous acid (ions) but is divided into a cathode reaction region and an anode reaction region by an electron permeable membrane. After introducing and energizing, treated water is taken out from the cathode reaction region and the anode reaction region, new treated water and treated water taken out from the anode reaction region are injected into the cathode reaction region, and then the above-mentioned The electrolysis reaction tank is energized to perform denitrification treatment on new water to be treated.

Reducing (nitrite) ions in the water to be treated,
When a series of denitrification treatment for converting generated ammonia into nitrogen gas and volatilizing it is carried out by a membrane separation type electrolytic reaction tank which is divided into a cathode reaction zone and an anode reaction zone, the electricity is generated in the anode reaction zone. The treated water after decomposition (anode treated water) contains a large amount of hypochlorous acid. Here, according to the fourth denitrification treatment method, when a series of denitrification treatments are performed again on new water to be treated after the series of denitrification treatments, a large amount of hypochlorous acid is added. Since the anode-treated water containing is introduced into the cathode reaction zone, the conductivity of the water to be treated is increased, and the efficiency of the nitrogen gas generation reaction can be increased.

Further, conventionally, in the denitrification treatment of water in a membrane separation type electrolytic reaction tank, the hypochlorous acid produced in the anode reaction zone was discarded as it is without being effectively utilized. On the other hand, according to the fourth denitrification treatment method, hypochlorous acid, which is a by-product of the anode reaction, can be effectively utilized in the denitrification treatment in the next step.

In the fourth method of denitrifying water, not only the anode-treated water but also the water treated in the cathode reaction zone (cathode-treated water) is re-treated in the denitrification treatment for new water to be treated. You may use it. That is, the denitrification treatment method of water in the case of reusing the cathode-treated water is the same as the fourth denitrification treatment method of water,
Treated water is taken out from the cathode reaction zone and the anode reaction zone, and new treated water and treated water taken out from the anode reaction zone are injected into the cathode reaction zone, and then further into the anode reaction zone from the cathode reaction zone. It is characterized in that the treated water taken out is injected and then the electrolysis reactor is energized.

Conventionally, the liquid introduced into the anode reaction zone is
Purified water such as tap water or the same treated water that is introduced into the cathode reaction zone has been used. However,
In the former case, there is a problem of wasting water resources, and in the latter case, the reduction of (nitrite) ions and the production of nitrogen gas do not occur in the cathode reaction zone. There is a problem that causes a decrease in On the other hand, chloride ions are contained to some extent in the water electrolyzed in the cathode reaction region by a series of denitrification treatments. In the above-mentioned denitrification treatment method according to the present invention, after finishing a series of denitrification treatments, when performing a series of denitrification treatments again on new water to be treated, cathode treated water containing chloride ions is treated. Since it is introduced into the anode reaction zone, the above-mentioned problems such as waste of water resources and reduction of nitrogen content removal rate do not occur. Moreover, the chloride ions contained in the cathode reaction water can be effectively utilized as a source of hypochlorite ions in the denitrification process of the next step. Moreover, since the amount of chloride ions introduced into the anode reaction region can be reduced, the processing cost can be reduced.

A fourth water treatment apparatus for use in the fourth method for denitrifying water according to the present invention for solving the above-mentioned problems comprises a cathode for reducing (nitrite) ions by an electrochemical reaction, and An anode that produces chlorine from a chloride ion by an electrochemical reaction, a membrane that does not permeate ammonia and hypochlorous acid (ion) but an electron, a cathode reaction zone that accommodates the cathode by the membrane, and It is provided with an electrolytic reaction tank divided into an anode reaction zone accommodating an anode, and a water passage for transferring water treated in the anode reaction zone into the cathode reaction zone. By using the fourth water treatment apparatus, the operation of transferring the anode-treated water to the cathode reaction zone can be easily and efficiently performed in the fourth method for denitrifying water.

In the fourth method for denitrifying water,
The water treatment device used when the cathode treated water is also reused is the fourth water treatment device, and further comprises a water passage for transferring the water treated in the cathode reaction region into the anode reaction region. It is characterized by By using the water treatment device, the operation of transferring the anode treated water to the cathode reaction zone in the denitrification treatment method of water, and the operation of transferring the cathode treated water to the anode reaction zone,
It can be performed easily and efficiently.

In the fourth water treatment device, the volume of the anode reaction zone is preferably smaller than the volume of the cathode reaction zone. By reducing the anode reaction region, the hypochlorous acid concentration of the treated water (anode treated water) subjected to the electrolytic treatment in the anode reaction region can be kept high. Therefore, the anode reaction region after the electrolytic treatment becomes a high-concentration hypochlorous acid source, and the effect of applying the electrolyte to the cathode reaction region becomes extremely high. Further, this makes it possible to efficiently achieve the nitrogen gas generation / removal reaction. Further, the high concentration of hypochlorous acid makes it possible to suppress fluctuations in the water level when adding an electrolyte to the cathode reaction region when starting a new denitrification process. This leads to the prevention of the situation where the amount of new treated water introduced into the cathode reaction zone becomes small, and more denitrification treatment of the treated water can be realized by one treatment. .

In the first to fourth methods for denitrifying water, acidic water may be supplied to the water to be treated stored in the electrolytic reaction tank to adjust the pH of the water to be treated. . The denitrification treatment method of water in the case of adjusting the pH of the water to be treated, in the denitrification treatment method of the first to fourth water, the acidic liquid is supplied to the electrolytic reaction tank to adjust the pH of the water to be treated. After the adjustment, electricity is applied to the electrolytic reaction tank.

In the conventional denitrification treatment method of water by an electrochemical reaction, the pH of the water to be treated shifts to the alkaline region as a series of denitrification treatments proceed. As a result, the reaction rate is lowered, and particularly in the case of water to be treated containing a high concentration of nitrogen, the reaction is almost stopped. On the other hand, according to the above method of denitrifying water, it is possible to suppress an increase in the pH of the water to be treated and adjust the value as appropriate, so that it is possible to prevent a decrease in the reaction rate.

The water treatment device used for adjusting the pH of the water to be treated is the first to fourth water treatment devices, further comprising an acidic liquid supply means connected to the electrolytic reaction tank. Is characterized by. By using the above-mentioned water treatment device, it is possible to easily prevent the pH of the water to be treated from rising during the denitrification treatment. When adjusting the pH of the water to be treated, hydrochloric acid and / or acidic water produced by electrolysis of saline can be used as the acidic liquid. When hydrochloric acid is used as the acidic liquid, the chloride ion derived from the hydrochloric acid can be used as a hypochlorous acid source. On the other hand, when acidic water electrolyzed by the diaphragm method is used as the acidic water, the nitrogen removal reaction can be efficiently performed.

When the pH of the water to be treated is adjusted, it is preferable to attach a pH meter to the electrolytic reaction tank or its cathode reaction zone. As a result, the pH in the electrolytic reaction tank
Can be easily controlled, and the reaction speed decreases,
It is possible to prevent the discharge of liquid that is extremely out of the neutral range.

In the second and fourth water treatment apparatuses, the anode has a surface coated with a film that does not transmit ammonia and hypochlorous acid (ions) but transmits electrons. In the third water treatment device, the second anode may have a surface coated with an electron-impermeable film that does not permeate ammonia and hypochlorous acid (ions). Good. In this case, it is possible to prevent the reverse reaction at the anode, and it is possible to obtain the same effect as that of the diaphragm-separated electrolytic reaction tank without partitioning the electrolytic reaction tank into the cathode reaction area and the anode reaction area. .

In the water treatment apparatus of the present invention, the cathode and the anode are plate-shaped electrodes and are arranged so as to face each other, and a terminal portion for connecting the electrode plate and a power source. Is preferably provided so as to project from the electric reaction surface of the electrode plate, and is arranged at a position where the cathode terminal portion and the anode terminal portion of the electrode do not face each other. In this way, by disposing the terminal portions of both electrodes so that they do not face each other, the wiring connection to the terminals can be simplified and the wiring can be performed easily, and thus the maintainability of the water treatment device is improved. It will be good.

In the above-mentioned water treatment device in which the terminal portions of both electrodes are arranged at positions not facing each other, when there are three or more electrodes in total and they are arranged alternately facing each other, More preferably, the terminal portions of the cathode and / or the terminal portions of the anode are connected by a conductive member. In this case, it is not necessary to connect the wiring to each electrode, and it is possible to reduce the risk of causing a defect such as a short circuit.

In the water treatment apparatus of the present invention, it is preferable that the cathode and / or the anode is directly fixed to the inner wall of the electrolytic reaction tank. In this case, a function as a holder for the electrode plate can be added to the electrolytic reaction tank itself, and as a result, the structure of the electrolytic reaction tank can be simplified. Further, in the water treatment device of the present invention, it is preferable that a bubble outlet is provided between the cathode and the anode. In this case, it is possible to prevent the scale from adhering to the electrode due to the bubbles sent out.

In the first, second and third water treatment apparatuses, the cathode is a box type, and the anode is fixed to a lid portion that closes the opening portion of the cathode. preferable. Further, in the case where the cathode has a box-shaped structure and the electrolytic reaction tank has the anode fixed to its lid, the cathode is divided into a plurality of chambers therein, It is preferable that an anode accommodated in each of the plurality of chambers is fixed to a lid portion that closes the opening portion of the cathode. As described above, since the cathode has the box-shaped structure, the electrode structure and the connection process of the wiring can be simplified, and the maintainability of the water treatment device becomes good.

The box-shaped cathode is more preferably in the form of a wire mesh. In this case, in order to form a plurality of chambers for the cathode, the cathode itself can be bent or braided and molded while being integrated,
Moreover, such processing can be easily performed. Therefore, a holder such as a spacer is not required, the structure can be simplified, and the workability such as wiring and maintenance can be improved by being integrated.

In the water treatment apparatus of the present invention, the electrolytic reaction tank is of a so-called diaphragm type in which the flow path of the water to be treated is arranged in a meandering state in the electrolytic reaction tank. It is preferable that In this case, the entire electrolytic reaction tank can be made compact while ensuring a long flow path. In addition, since the flow path can be made longer, the contact time between the electrode and the water to be treated becomes longer, so that the ability to remove nitrogen can be improved.

[0047]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a denitrification treatment method for water and a water treatment apparatus according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an example of a water treatment device according to the present invention. In the water treatment device shown in FIG.
The water to be treated is introduced into the reaction zone 22 by opening the electromagnetic valve 31 of the water to be treated inlet 30 connected to the cathode reaction zone 22 of the electrolytic reaction tank 10.

The electrolysis reaction tank 10 is provided with a cation exchange membrane 24 as a membrane which does not permeate ammonia and hypochlorous acid (ions) but permeates electrons, and the cation exchange membrane 24 causes an electrolytic reaction. The inside of the tank 10 is partitioned into a cathode reaction zone 22 and an anode reaction zone 23. In the water treatment device shown in FIG. 1, the anode reaction zone 23 is designed smaller than the cathode reaction zone 22. Membrane filters (for example, ultrafiltration membranes) as well as cation exchange membranes can be cited as examples of membranes that do not permeate ammonia and hypochlorous acid (ions) but permeate electrons.

In the water treatment device shown in FIG. 1, a DC power source 25
Although the cathode 20 and the anode 21 are each one (one pair) connected to the electrode plate, there may be a plurality of pairs of the electrodes. Further, as long as the cathodes and the anodes are alternately arranged, the same number of cathodes and anodes need not be provided. Cathode reaction area 22
Is provided with a discharge port 34 for discharging the cathode treated water, and the discharge of the treated water is controlled by a solenoid valve 35. Similarly, the anode reaction region 23 is also provided with a discharge port 32 for discharging the anode treated water and a solenoid valve 33 for controlling the discharge of the anode treated water. The anode reaction region 23 is connected to an anode treatment water tank 42 in addition to the anode treatment water drain port 32, and the cathode reaction region 22 of the electrolytic reaction tank 10 is connected via the tank 42.
A water passage 44 leading to is provided. Through this water passage 44, the anode treated water can be transferred into the cathode reaction region 22.

The electrolytic reaction tank 10 is further provided with a path for supplying hypochlorite ions. In this route, saline is supplied from the salt tank 36 to the hypochlorous acid generator 37, and hypochlorous acid is generated. The generated hypochlorous acid is injected into the cathode reaction region 22 in the electrolytic reaction tank 10 by the pump 38 and is used for the nitrogen removal reaction. In FIG. 1, the path denoted by reference numeral 39 is the supply path of hypochlorous acid,
The route denoted by reference numeral 40 indicates the saline supply passage, and the route denoted by reference numeral 41 indicates the water supply passage. The hypochlorous acid generated by the hypochlorous acid generator 37 may be supplied to the anodized water tank 42. The salt tank 36 and the hypochlorous acid generator 37 may be devices (for example, a hypochlorous acid tank) for directly injecting a chemical solution such as hypochlorous acid. In addition, ozone may be injected into the water to be treated instead of hypochlorous acid.

The anode treated water containing hypochlorous acid produced in the anode reaction zone 23 is taken out from the anode reaction zone 23 and temporarily stored in the anode treated water tank 42. Furthermore, the cathode reaction zone 23 is generated by the pump 43.
Will be introduced to. In FIG. 1, reference numeral 45 is a pump for introducing the anode-treated water into the tank 42, and reference numerals 46 and 4 are provided.
Reference numerals 7 are solenoid valves for controlling the supply of the anode treated water, respectively. The water treatment apparatus shown in FIG. 1 further includes a water passage 48 for transferring the cathode treated water to the anode reaction region. After the completion of the nitrogen removal reaction, through this water passage 48,
A part of the treatment liquid treated in the cathode reaction zone 22 can be transferred into the anode reaction zone 23 by the pump 49.

FIG. 2 is a schematic view showing another example of the water treatment device according to the present invention. In the water treatment device shown in FIG.
The water to be treated is introduced into the reaction zone 22 by opening the electromagnetic valve 31 of the water to be treated inlet 30 connected to the electrolytic reaction tank 11.

In this example, an electrolytic reaction tank 1 without a diaphragm is used.
1 is used, but an electrolytic reaction tank which is divided into a cathode reaction zone and a cathode reaction zone by a membrane which does not permeate the above-mentioned ammonia and hypochlorous acid (ions) but permeates electrons may be used. . In the water treatment device shown in FIG. 2, since hypochlorous acid is directly injected into the electrolytic reaction tank 11,
The anode 21 does not have to be capable of generating chlorine from chloride ions by an electrochemical reaction.

Reference numeral 25 is a DC power supply for applying a voltage to the cathode 20 and the anode 21 as in the case shown in FIG. In FIG. 2, the cathode 20 and the anode 21
Although a pair of is provided, a plurality of these may be provided. The electrolytic reaction tank 11 has a discharge port 34 for discharging treated water.
The discharge of the treated water is controlled by the solenoid valve 35. The electrolytic reaction tank 11 is further provided with a path for supplying hypochlorite ions. The configuration of the path for supplying the hypochlorite ion and the reference numerals 36 to 41 are the same as those shown in FIG.

As described above, the treated water from which the nitrogen content has been removed contains a large amount of chlorine ions. A part of this treated water is taken into the water passage 44a and sent to the treated water tank 42a by the pump 45. The treated water taken in the tank 42a is introduced into the electrolytic reaction tank by the pump 43a when the electrolytic reaction tank of the hypochlorous acid generator 37 is emptied, and is regenerated to generate hypochlorous acid. Used.

FIG. 3 is a schematic view showing still another example of the water treatment device according to the present invention. In the water treatment apparatus shown in FIG. 3, the water to be treated is the same as in the water treatment apparatus shown in FIG. 2 by opening the electromagnetic valve 31 of the water to be treated inlet 30 connected to the electrolytic reaction tank 11. It is introduced into the reaction zone 22. Electrolytic reaction tank 11, cathode 20, anode 21
The DC power supply 25 is the same as the water treatment device shown in FIG. Although a pair of the cathode 20 and the anode 21 is provided in this example, a plurality of these may be provided.

In the example shown in FIG. 3, the electrolytic reaction tank 11 which does not use a diaphragm is used. However, the cathode reaction region is formed by a membrane which does not permeate the aforementioned ammonia and hypochlorous acid (ions) but permeates electrons. An electrolytic reaction tank divided into a cathode reaction zone and a cathode reaction zone may be used. When the electrolytic reaction tank 11 is of a separable membrane type, a saline supply path 40a described later is connected to the cathode reaction zone. A discharge port 34 for discharging the treatment liquid is provided in the electrolytic reaction tank 11, and the discharge of the treatment water is controlled by a solenoid valve 35.

The electrolytic reaction tank 11 is further provided with a path 40a for supplying saline. The salt 36b is accommodated in the bottom of the salt tank 36a, and the salt tank 3
6a is provided with a pipe 50 for supplying saline to the electrolytic reaction tank 11. The water supplied to the salt tank 36a from the water supply path 41a passes through the portion where the salt 36b is accumulated, so that the salt water has a high concentration. This salt solution is supplied to the electrolytic reaction tank 1 by the pump 38a.
1, the concentration of chloride ions in the water to be treated is adjusted. The method for controlling the chloride ion concentration is the cathode 2
It may be performed by detecting the magnitude of the current flowing between 0 and the anode 21.

FIG. 4 is a schematic view showing still another example of the water treatment device according to the present invention. Among the water treatment devices shown in FIG. 4, reference numerals 25, 30, 31, 36a, 36b, 38a,
All of 40a, 41a and 50 are the same as in FIG. Reference numeral 12 is an electrolytic reaction tank for producing hypochlorous acid (first electrolytic reaction tank), and reference numerals 20a and 21a are a cathode (first cathode) and an anode (first anode) for producing hypochlorous acid. is there.

Electrolyzed in the first electrolytic reaction tank 12,
As a result, the water to be treated containing a large amount of hypochlorous acid is introduced into the next electrolytic reaction tank for nitrogen removal (second electrolytic reaction tank) 13 by the pump 51. In the second electrolytic reaction tank 13, the water to be treated is electrolyzed by the cathode (second cathode) 26 and the anode (second anode) 27 for nitrogen removal, and the nitrogen content is removed. Since the first electrolytic reaction tank 12 of the water treatment apparatus shown in FIG. 4 does not perform the nitrogen content removal treatment, the first cathode 20a is
It does not have to be capable of reducing (nitrite) ions by an electrochemical reaction. On the other hand, the second electrolytic reaction tank 13
Since the water to be treated containing a large amount of hypochlorous acid is introduced, the second anode 27 does not have to be capable of generating chlorine from chloride ions by an electrochemical reaction.

In the example shown in FIG. 4, neither the first electrolytic reaction tank 12 nor the second electrolytic reaction tank 13 uses a diaphragm, but the aforementioned ammonia and hypochlorous acid (ions) are used. You may use the electrolytic reaction tank divided into the cathode reaction zone and the cathode reaction zone by the membrane which does not permeate | transmit but electron. When the electrolytic reaction tanks 12 and 13 are of the separable membrane type, both the saline supply path 40a and the water to be treated inlet 52 are connected to the anode reaction zone.

In FIG. 4, reference numeral 34 is an outlet for discharging the treated water from the second reaction tank 13, reference numeral 35 is an electromagnetic valve for controlling the discharge of the treated water, and reference numerals 35a and 51 are the first.
The electromagnetic valve and the pump for controlling the introduction of the water to be treated from the reaction tank 12 to the second reaction tank 13 are shown, and the reference numeral 52 denotes the inlet of the water to be treated to the second electrolytic reaction tank 13.

FIG. 5 is a schematic view showing still another example of the water treatment device according to the present invention. In the water treatment device shown in FIG. 5, the water to be treated is the same as in the water treatment device shown in FIG. 2 by opening the electromagnetic valve 31 of the water to be treated inlet 30 connected to the electrolytic reaction tank 14. It is introduced into the reaction zone 22. The electrolytic reaction tank 14 is divided into a cathode reaction region 22 and an anode reaction region 23 by a diaphragm 24,
A cathode 20 and an anode 21 are provided on each. Water to be treated may be introduced into the anode reaction region 23, or tap water or the like may be introduced.

In the water treatment device shown in FIG. 5, the electrolytic reaction tank 1
Since the treatment for removing the nitrogen content is not performed in the anode reaction zone of No. 4, the anode 21 does not have to be capable of generating chlorine from chloride ions by an electrochemical reaction. Reference numeral 25 is a DC power supply for applying a voltage to the cathode 20 and the anode 21. Although a pair of the cathode 20 and the anode 21 is provided in this example, a plurality of these may be provided.

A discharge port 34 for discharging the cathode treated water is provided in the cathode reaction region 22, and the discharge of the treated water is controlled by a solenoid valve 35. Similarly, the anode reaction region 23 is also provided with a discharge port 32 for discharging the anode treated water and a solenoid valve 33 for controlling the discharge of the anode treated water. In the example shown in FIG. 5, the electrolytic reaction tank 14 using a diaphragm is used, but the cathode reaction zone and the cathode reaction region are formed by a membrane that does not permeate the above-mentioned ammonia and hypochlorous acid (ions) but permeates electrons. You may use the electrolytic reaction tank which is not divided into the area.

The electrolytic reaction tank 14 is further provided with a path for supplying hypochlorite ions. The configuration of the path for supplying the hypochlorite ion and the reference numerals 36 to 41 are the same as those shown in FIG. The salt tank 36 and the hypochlorous acid generator 37 may be devices (for example, a hypochlorous acid tank) for directly injecting a chemical solution such as hypochlorous acid. In addition, ozone may be injected into the water to be treated instead of hypochlorous acid.

FIG. 6 is a schematic view showing still another example of the water treatment device according to the present invention. In the water treatment device shown in FIG. 6, the water to be treated is the same as in the water treatment device shown in FIG. 3 by opening the electromagnetic valve 31 of the water to be treated inlet 30 connected to the electrolytic reaction tank 11. It is introduced into the reaction zone 22. Electrolytic reaction tank 11, cathode 20, anode 21
The DC power supply 25 is the same as the water treatment device shown in FIG. Although a pair of the cathode 20 and the anode 21 is provided in this example, a plurality of these may be provided.

A discharge port 34 for discharging the treatment liquid is provided in the electrolytic reaction tank 11, and the discharge of the treatment water is controlled by a solenoid valve 35. The electrolytic reaction tank 11 may be of a type in which the cathode 20 and the anode 21 are separated by an exchange membrane. The electrolytic reaction tank 11 is further provided with a path 39a for supplying acidic water.
The acidic water supply device is an electrolytic reaction tank including a cathode 60, an anode 61, a diaphragm 64, and a DC power source 65,
The cathode reaction region 62 and the anode reaction region 63 are provided with a water supply passage 66 and a saline supply passage 67, respectively.

In FIG. 6, reference numeral 39a denotes a hypochlorous acid supply path, reference numerals 53 and 54 denote an acidic water supply device and a solenoid valve for controlling water supply to the salt tank 56, and reference numeral 55 denotes a saline solution. 56 is a salt tank, 57 is a pump for supplying saline solution, 58 is a pump for supplying acidic water, and 59 is a supply of acidic water. Reference numeral 68 denotes a solenoid valve for controlling the drainage port of the acidic water supply device, and reference numeral 69 denotes a solenoid valve for controlling the discharge from the discharge port 68.

The acidic water produced in the anode reaction zone 63 of the acidic water supply apparatus by the diaphragm type electrolysis method is pumped by the pump 72.
Is introduced into the electrolytic reaction tank 11 by using
The increase in pH of the water to be treated in 1 is suppressed and the nitrogen removal reaction is promoted. The cathode-treated water generated in the cathode reaction zone 62 of the acidic water supply device can be used for other purposes as alkaline water. The acidic water supply device shown in FIG. 6 is not limited to the electrolytic reaction tank, and may be a tank for supplying an acid such as hydrochloric acid or sulfuric acid. When hydrochloric acid is used as the acid, chloride ions in hydrochloric acid can be used as a hypochlorous acid source in the electrolytic reaction tank 11.

FIG. 7 is a diagram showing an example of an electrode plate (cathode and anode) in the water treatment apparatus of the present invention, (a) is its front view and (b) is its side view. Figure 7
In the electrode plate shown in (1), the cathode 70 and the anode 71 are plate-shaped electrodes and are arranged to face each other. Further, the terminal portions 72 and 73 for connecting the cathode 70 and the anode 71 to the power source are provided so as to project from the electric reaction surfaces of the cathode 70 and the anode 71, that is, the portions that are immersed in the water to be treated during the denitrification treatment of water. In addition, the two terminal portions 72, 73 are arranged at positions where they do not overlap each other. Therefore, the terminal portion 7
Wiring connection to 2, 73 is simplified, and wiring can be easily performed. In FIG. 7, a member denoted by reference numeral 76 is a spacer for keeping the distance between the cathode 70 and the anode 71.

FIG. 8 is a diagram showing an example of the water treatment apparatus of the present invention having three or more electrode plates (cathode and anode). (A) is a front view thereof, and (b) is a view thereof. It is a side view. According to the arrangement of the electrode plate shown in FIG. 8, the protrusions of the same type of electrodes are arranged at positions overlapping with each other, and the protrusions are overlapped between electrodes of different types (between the cathode 70 and the anode 71). It is arranged not to. Therefore, for example, the electrodes of the same type can be easily connected by the conductive member 77, and even in such a case, it is possible to sufficiently prevent a short circuit from occurring between electrodes of different types. In FIG. 8, members denoted by reference numeral 76 a are the cathode 70 and the anode 7.
It is a spacer for keeping the distance between the two.

FIG. 9 is a sectional view showing an example of the electrolytic reaction tank in the water treatment device of the present invention. In the electrolytic reaction tank 80 shown in FIG. 9, a groove 78 is provided on the bottom surface, and the cathode 70 and the anode 71 are both provided with the groove 78.
Is inserted and fixed in. As described above, in the electrolytic reaction tank 80 shown in FIG. 9, the reaction tank 80 itself is provided with a function as a holder for the electrode plate, and therefore, the number of the spacers 76a can be reduced. The structure of the tank 80 can be simplified.

The electrolytic reaction tank 80a shown in FIG. 10 is the same as the electrolytic reaction tank 80 shown in FIG. 9 except that a discharge port 79 for discharging bubbles is further provided between the electrode plates. Outlet 79
The air sent out from the electrodes becomes bubbles and becomes the electrodes 70, 71.
In between. The bubbles have a function of preventing the scale from adhering to the surface of the electrode, so that the efficiency of the electrolytic reaction can be enhanced.

FIG. 11 shows the water treatment device of the present invention.
It is a figure which shows an example of an electrode when a cathode has a box-shaped structure. In the electrode shown in FIG. 11, the cathode 81 has a wire mesh shape and a box shape, and has a plurality of chambers. on the other hand,
The anode 82 is fixed to a lid portion 83 combined with the box-shaped cathode 81, and a plurality of anodes are integrated with the lid portion 83. By arranging the anode 82 so as to be housed in each chamber of the cathode 81 when the box-shaped cathode 81 and the lid 83 are combined, the electrode structure is simplified and the workability during maintenance is improved. Can be achieved. In particular, a plurality of anodes 82
Since is integrated with the lid 83, the wiring to the anode can be made extremely simple.

12 and 13 are views showing an example of an electrolytic reaction tank in which the path of the water to be treated meanders.
2 is a plan sectional view showing an example of an electrolytic reaction tank in which the flow path meanders in a horizontal plane. On the other hand, FIG. 13 is a vertical cross-sectional view showing an example of an electrolytic reaction tank in which the flow path meanders in the vertical direction.

The electrolytic reaction tank 8 shown in FIGS. 12 and 13.
4, 85 are flow paths 86, 8 of the water to be treated in any case.
Since 7 is meandering, the contact time between the electrode 88 and the water to be treated is long, and as a result, the ability to remove nitrogen is excellent.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of a water treatment device according to the present invention.

FIG. 2 is a schematic diagram showing another example of the water treatment device according to the present invention.

FIG. 3 is a schematic view showing still another example of the water treatment device according to the present invention.

FIG. 4 is a schematic view showing still another example of the water treatment device according to the present invention.

FIG. 5 is a schematic view showing still another example of the water treatment device according to the present invention.

FIG. 6 is a schematic view showing still another example of the water treatment device according to the present invention.

FIG. 7A is a front view showing an example of an electrode plate in which a terminal portion is provided so as to project from an electric reaction surface, and FIG. 7B is a side view thereof.

8A is a front view showing another example of an electrode plate in which a terminal portion is provided so as to project from an electric reaction surface, FIG. 8B is a side view thereof, and FIG. 8C is a plan view thereof. is there.

FIG. 9 is a cross-sectional view showing an example of an electrolytic reaction tank having a function as a holder for an electrode plate.

FIG. 10 is a cross-sectional view showing an example of an electrolytic reaction tank provided with a function as a holder for an electrode plate and a bubble outlet.

11A is an exploded perspective view showing an example of a box-shaped cathode, and FIG. 11B is a front view showing a state in which the cathode and a lid portion including an anode are combined. FIG.

FIG. 12 is a plan cross-sectional view showing an example of an electrolytic reaction tank in which a path of water to be treated meanders.

FIG. 13 is a vertical cross-sectional view showing an example of an electrolytic reaction tank in which a path of water to be treated meanders.

[Explanation of symbols]

10 Electrolysis reaction tank 11 Electrolytic reaction tank 12 First electrolytic reaction tank 13 Second electrolytic reaction tank 20 cathode 20a cathode 21 Anode 21a anode 22 Cathode reaction zone 23 Anode reaction zone 24 diaphragm 26 cathode 27 Anode 44 (Anode treated water) water passage 44a waterway 48 (cathode treated water) water passage 71 Anode 72 Terminal 73 Terminal 74 Projection 75 Projection 77 Conductive member 79 exit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C25B 9/02 302 C25B 11/02 301 9/10 306 9/18 C02F 1/46 101A 11/02 C25B 9 / 00 D 301 E 306 11/20 9/00 R (72) Inventor Shigeki Yoshida 2-5-5 Keihan Hondori, Moriguchi City, Osaka Prefecture Sanyo Electric Co., Ltd. (72) Minoru Nakanishi Moriguchi City, Osaka Prefecture Keihan Hondori 2-5-5 Sanyo Electric Co., Ltd. (72) Inventor Minoru Kishi Minoraku-shi, Osaka Keihan Hondori 2-5-5 Sanyo Electric Co., Ltd. (72) Inventor Kazushi Kawamura Osaka 2-5-5 Keihanhondori, Moriguchi-shi Sanyo Electric Co., Ltd. (72) Inventor Yoshihiro Inamoto 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. F-term (reference) 4D061 DA02 DA08 DB10 DB18 DC14 EA02 EA04 EB04 EB13 EB14 EB17 EB19 EB20 EB35 EB39 ED03 ED13 ED20 GC06 4K011 AA10 BA07 CA03 CA04 CA10 DA03 4K021 AB07 BA02 BA03 BC01 BC03 CA02 CA09 CA10 DA05 DA09 DB05 DB12 DB31 DB43 DB43

Claims (22)

[Claims] 1. After introducing water to be treated and hypochlorous acid (ions) and / or ozone into an electrolytic reaction tank provided with a cathode and an anode for reducing (nitrite) ions by an electrochemical reaction. A method for denitrifying water, comprising energizing the electrolytic reaction tank. 2. The electrolytic reaction tank is divided into a cathode reaction region and an anode reaction region by an electron-permeable membrane that does not allow ammonia and hypochlorous acid (ions) to pass therethrough, and The hypochlorous acid (ion) and /
Alternatively, the method for denitrifying water according to claim 1, wherein ozone is introduced into the cathode reaction zone. 3. Hypochlorous acid (ions) introduced into the electrolytic reaction tank is produced by an electrolytic hypochlorous acid generator, and is introduced into the electrolytic hypochlorous acid generator. The method for denitrifying water according to claim 1 or 2, wherein the electrolyte solution to be treated is treated water which has been subjected to denitrification treatment in the electrolytic reaction tank. 4. Treated water is introduced into an electrolytic reaction tank provided with a cathode for reducing (nitrite) ions by an electrochemical reaction and an anode for producing chlorine from chloride ions by an electrochemical reaction, and further chloride ions are introduced. Is supplied to adjust the chloride ion concentration of the water to be treated, and then the electrolytic reaction tank is energized to perform a denitrification treatment method of water. 5. Treated water is introduced into a first electrolytic reaction tank provided with a first cathode and a first anode that produces chlorine from chloride ions by an electrochemical reaction, and chloride ions are further added. After supplying and adjusting the chloride ion concentration of the water to be treated, the first electrolytic reaction tank is energized to generate hypochlorous acid, and then the water to be treated in the first electrolytic reaction tank is generated. Is introduced into a second electrolytic reaction tank provided with a second cathode that reduces (nitrite) ions by an electrochemical reaction and a second anode, and the second electrolytic reaction tank is energized. A method for denitrifying water, which comprises: 6. The first electrolytic reaction tank is configured by partitioning a cathode reaction region and an anode reaction region by an electron-permeable membrane that is impermeable to ammonia and hypochlorous acid (ions). And chloride ions are supplied to the anode reaction region of the first electrolytic reaction tank, and the water to be treated in the cathode reaction region and the anode reaction region is energized after the first electrolytic reaction tank is energized. The method for denitrifying water according to claim 5, wherein the water is introduced into the second electrolytic reaction tank. 7. A cathode, which reduces (nitrite) ions by an electrochemical reaction, and an anode, which produces chlorine from chloride ions by an electrochemical reaction, and permeates ammonia and hypochlorous acid (ions). Instead, the water to be treated is introduced into the electrolytic reaction tank which is divided into the cathode reaction region and the anode reaction region by the electron permeable membrane, and the treated water is discharged from the cathode reaction region and the anode reaction region. Taking out and injecting new treated water and treated water taken out from the anode reaction zone into the cathode reaction zone, then energizing the electrolytic reaction tank to denitrify the new treated water. Characteristic water denitrification method. 8. Treated water is taken out from the cathode reaction region and the anode reaction region, new treated water and treated water taken out from the anode reaction region are injected into the cathode reaction region, and then the anode reaction region is further added. The method for denitrifying water according to claim 7, wherein after the treated water taken out from the cathode reaction zone is injected into the tank, electricity is supplied to the electrolytic reaction tank. 9. The method for denitrifying water according to claim 1, wherein an acidic liquid is supplied to the electrolytic reaction tank to adjust the pH of the water to be treated, and then the electricity is supplied to the electrolytic reaction tank. . 10. A cathode for reducing (nitrite) ions by an electrochemical reaction, an anode, an electrolytic reaction tank containing the cathode and the anode, a hypochlorous acid supply means and / or an ozone supply means, A water treatment device comprising a water passage connected to the electrolytic reaction tank from a supply means. 11. An electrolysis-type hypochlorous acid generator for producing hypochlorous acid (ions) by an electrochemical reaction, wherein said hypochlorous acid supply means is provided in said electrolytic reaction tank and in said electrolytic reaction tank. 11. The water treatment apparatus according to claim 10, further comprising a water passage for transferring the treated water that has been subjected to denitrification treatment into the electrolytic hypochlorous acid generator. 12. A cathode for reducing (nitrite) ions by an electrochemical reaction, an anode for producing chlorine from chloride ions by an electrochemical reaction, an electrolytic reaction tank containing the cathode and the anode, and the electrolytic reaction. And a chloride ion supply means connected to the tank. 13. A first cathode, and a first anode that produces chlorine from chloride ions by an electrochemical reaction,
A first electrolytic reaction tank for housing, a chloride ion supply means connected to the first electrolytic reaction tank, and a second reducing (nitrite) ion by an electrochemical reaction.
Of water and a second electrolytic reaction tank that accommodates the cathode and the second anode, and a water passage that is connected from the first electrolytic reaction tank to the second electrolytic reaction tank. 14. A cathode that reduces (nitrite) ions by an electrochemical reaction, an anode that produces chlorine from chloride ions by an electrochemical reaction, and an electron that does not permeate ammonia and hypochlorous acid (ions). A membrane permeable to water, an electrolytic reaction tank defined by the membrane into a cathode reaction zone containing the cathode and an anode reaction zone containing the anode, and water treated in the anode reaction zone to the cathode. A water treatment device provided with a water passage for transferring into the reaction zone. 15. The water treatment apparatus according to claim 14, further comprising a water passage for transferring water treated in the cathode reaction zone into the anode reaction zone. 16. The water treatment apparatus according to claim 10, further comprising an acidic liquid supply means connected to the electrolytic reaction tank. 17. The surface of the anode is coated with a film that is impermeable to ammonia and hypochlorous acid (ions) but is permeable to electrons.
The water treatment device according to any one of 1. 18. The water treatment device according to claim 13, wherein the second anode has a surface coated with an electron-impermeable film that is impermeable to ammonia and hypochlorous acid (ions). 19. The cathode and the anode are plate-shaped electrodes and are arranged so as to face each other, and a terminal portion for connecting the electrode plate and a power source is an electric reaction of the electrode plate. 11. The electrode is provided so as to project from the surface, and is arranged at a position in which the cathode terminal portion and the anode terminal portion of the electrode do not face each other.
18. The water treatment device according to any one of 18. 20. The cathodes and the anodes are plate-shaped electrodes, and the total number of the electrodes is three or more, and the electrodes are arranged alternately facing each other, and the terminal portions of the cathodes and / or the anodes are arranged. 20. The water treatment device according to claim 19, wherein the terminal portions of are connected by a conductive member. 21. The water treatment apparatus according to claim 10, wherein the cathode is box-shaped, and the anode is fixed to a lid portion that closes an opening portion of the cathode. 22. The cathode is wire mesh-shaped.
The described water treatment device.