JPH10235362A - Electrode device, phosphorus-removal apparatus using the same and wastewater treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode device capable of prolonging the life of an electrode plate in a phosphorus-removal apparatus wherein phosphate ion in water is deposited as insoluble metallic salt by electrolysis. SOLUTION: In an electrode device used in a phosphorus-removal apparatus wherein phosphate ion in water is deposited as insoluble metallic salt by electrolysis, an electrode plate 1 composed of a metal which generates phosphate salt insoluble in water by being reacted with phosphate ion, and an electricity conducting body 2 conducted to a power source by being extended from the electrode plate 1 are provided. In this case, a protective film 3 covering a surface is provided around a joint part of the electricity conducting body 2 to the electrode plate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode device useful for removing phosphorus contained in water such as domestic wastewater by electrolysis, and a dephosphorization device and a sewage treatment device using the same.

[0002]

2. Description of the Related Art One of the environmental problems is domestic wastewater. Among the pollutants contained in the wastewater, nitrogen and phosphorus components cause eutrophication of rivers and lakes. Generally, household wastewater is treated by biological or chemical methods in a large-scale purification facility in an area with a sewage treatment facility.However, in an area without a sewage treatment facility, If it is not purified at home, it will directly flow out to rivers and the like through sewage. In recent years, the installation of a sewage treatment apparatus such as a merged septic tank for general households has been encouraged. Conventionally, in a domestic sewage treatment apparatus, generally,
First, pretreatment is performed to settle and remove relatively large dirt contained in the wastewater in the pretreatment tank, and the microorganism is decomposed by the action of microorganisms in the activated sludge tank to precipitate as sludge. Is adopted.
However, a domestic-level sewage treatment apparatus is desired to have a function of removing phosphorus with a poor effect of removing phosphorus and stably removing phosphorus.

[0003]

On the other hand, in recent years, technical development of a method for removing a phosphorus component in a domestic-level sewage treatment apparatus has been carried out. For example, a phosphorus component contained in sewage is electrolyzed. Is effective. This method will be described. By performing electrolysis in sewage using an electrode made of a metal that forms a metal salt insoluble in water by combining with phosphate ions, the metal is ionized and eluted from the anode. It precipitates as an insoluble metal salt by binding to phosphate ions, and the phosphorus component is removed by precipitating or filtering this.

[0004] The problem of adopting the method of removing phosphorus components by electrolysis in a domestic-level sewage treatment apparatus is that a stable dephosphorization effect can be obtained in a phosphorus removal apparatus for performing the method. , Easy maintenance and long life. Here, in the above dephosphorization device, the anode electrode plate gradually dissolves in water by electrolysis and becomes thinner, and eventually the electrode plate reaches the end of its life and needs to be replaced. From a viewpoint, it is ideal that the electrode plate can be used until it is completely dissolved and disappears. However, for example, if a portion of the electrode plate that receives power supply from a power supply disappears before other portions, electrolysis cannot be performed at that time.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a dephosphorization apparatus for depositing phosphate ions in water into insoluble metal salts by electrolysis to deposit them. An object of the present invention is to provide an electrode device capable of extending the life of an electrode plate, and a phosphorus removal device and a sewage treatment device using the same.

[0006]

SUMMARY OF THE INVENTION An electrode device according to the present invention is used in a dephosphorization device that precipitates phosphate ions in water into insoluble metal salts by electrolysis, and reacts with phosphate ions. An electrode plate made of a metal that forms a phosphate metal salt that is insoluble in water, and an electric conductor that extends from the electrode plate and conducts to a power source. Is provided with a protective film for covering the surface. In this electrode device, since the periphery of the joint between the current conductor and the electrode plate is covered with the protective film, when the electrode device is used as an anode in the dephosphorization device, the current conductor, the electrode plate, Is not directly in contact with water, and as a result, this portion is prevented from being reduced by electrolysis. Therefore, it is possible to supply current to the electrode plate from the current-carrying body until the other portions except for the periphery of the coupling portion are reduced and disappear.

In the electrode device of the present invention, the current-carrying body is made of a conductive material that is hardly eluted even when a positive current is applied in a state of being immersed in water at least as compared with the electrode plate. The electrode plate is preferably made of a metal having a lower ionization tendency than the metal constituting the electrode plate.

Further, in the electrode device of the present invention, it is preferable that at least one of a concave portion and a through hole is formed at one or more places in the electrode plate. In other words, since the electrode plate tends to be preferentially reduced from the portion having the edge,
By forming a concave portion or a through hole and forming an edge portion in the middle of the electrode plate, the electrode plate is not only reduced in its side edges and corners, but is also reduced in a balanced manner so that the electrode plate lasts as a whole as a whole. This is because they can be controlled as follows.

[0009] When the electrode device of the present invention is used in a dephosphorization device that precipitates phosphate ions in water into insoluble metal salts by electrolysis, the electrode device is placed in an electrolytic cell to which water containing phosphate ions is supplied. It is preferable to provide an electrode plate as a positive electrode. As described above, in the dephosphorization apparatus provided with the electrode plate of the electrode device of the present invention as a positive electrode, a positive current is applied to the electrode plate to perform electrolysis, whereby phosphate ions in water in the electrification tank are converted to the electrode. The electrode plate can be combined with the metal ions eluted from the plate and precipitated as an insoluble metal salt. At this time, since the electrode plate can be used for a long period of time, the frequency of replacement maintenance can be reduced.

Further, a sewage treatment apparatus using the above-mentioned dephosphorization apparatus together with an activated sludge tank and filtering the water treated therewith by a filtration apparatus can perform sewage treatment including a phosphorus component. At the same time, the frequency of maintenance for replacing the electrode plate is reduced.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. Here, FIG. 1 shows an electrode device according to an embodiment of the present invention, in which (a) is a front view and (b) is a top view thereof. FIG. 2 is a schematic cross-sectional view showing an example of a dephosphorization device and a sewage treatment device using the electrode device shown in the embodiment.

As shown in FIG. 1, the electrode device according to this embodiment includes an electrode plate 1 formed in a rectangular shape, and an electric conductor 2 extending from the electrode plate 1. Electrode plate 1
A protective film 3 for covering the surface is provided around the joint portion.

The electrode plate 1 is made of aluminum. The material of the electrode plate 1 may be any metal that reacts with phosphate ions to form a water-insoluble metal phosphate salt. Other than aluminum, an easily available material such as iron is exemplified. The electrode plate 1 has a through hole 4.
Are formed in a plurality of places in the middle of the plate.
When electrolysis is performed in water using the
Aluminum is preferentially eluted from the portion and the weight decreases. The electrode plate 1 may be provided with a non-penetrating concave portion instead of the through hole 1 for the same purpose.

The current-carrying body 2 is formed in a rod shape from stainless steel, and extends upward from two places at the upper end of the electrode plate 1. A thread is formed at the lower end of the current-carrying body 2, while a screw hole is formed at the upper end of the electrode plate 1 so that the lower end of the current-carrying body 2 can be screwed to the upper end of the electrode plate 1 and fixed. The electrode plate 1 can be hung from above and supported by using the current-carrying body 2 as a support rod. The material of the current conductor 2 may be any conductive material that is less ionizable than at least the electrode plate 1 when a positive current is supplied to the electrode plate 1. In the present embodiment, the material is excellent in availability and strength. Although stainless steel is used, it is preferable that the metal is made of a metal such as gold, silver, copper, or the like, which has a lower ionization tendency than the metal constituting the electrode plate 1, and a carbon material can also be used. is there. Further, the current-carrying body 2 may be welded to the electrode plate 1, and furthermore, if the electrode plate 1 can be supported by other supporting means in use, the function of supporting the electrode plate 1 is unnecessary, and Can be substituted.

The protective film 3 covers the joint between the current-carrying body 2 and the electrode plate 1 and its surroundings so as not to be exposed.
It is formed by nickel plating. When the protective film 3 is electrolyzed in water using the electrode plate 1 as an anode, the film itself does not elute into water, and at the same time, the periphery of the joint between the current-carrying body 2 and the electrode plate 1 is directly exposed to water. Any material may be used as long as it prevents contact, and in addition to the nickel plating, a metal film having a smaller ionization tendency than the current-carrying member 2 and the electrode plate 1 or an organic polymer film such as various resin coatings is exemplified.

The electrode device according to the embodiment is, for example, shown in FIG.
As shown in the above, it is used as an anode in a dephosphorization apparatus that precipitates phosphate ions in water into an insoluble metal salt by electrolysis, and is particularly useful as a dephosphorization apparatus for sewage treatment equipment. Things.

Referring to the dephosphorizing apparatus shown in FIG. 2, the electrolytic cell 10 also functions as an activated sludge tank 30, that is, the dephosphorizing apparatus is integrated with the activated sludge tank 30. It is designed to work as a sewage treatment device. Two electrode plates 1 are provided vertically as anodes 12 in the electrolytic cell 10, and two cathodes 13 are provided vertically facing each other. 2 which is the anode 12
Each of the current-carrying members 2 extending above the one electrode plate 1 is connected to the positive electrode of the DC power supply 50 in parallel by a conductor, while the two cathodes 13 are connected in parallel to the negative electrode of the DC power supply 50 by a conductor. It is connected.

In the electrolytic cell 10, a box-shaped flat membrane filter 20 whose inside and outside are separated by a sheet filter is provided as a filtration device, and one end of the flat membrane filter 20 has one end. And the other end is connected to the electrolytic cell 1.
A drainage channel 40 is provided to the outside, and a drainage pump 41 is provided in the drainage channel 40.

The electrolytic cell 10 is provided with a sewage inflow channel 31 into which sewage flows. Water flowing from the sewage inflow channel 31 is supplied into the electrolytic cell 10 by an anode 12, a cathode 13, and a flat membrane filter 20. It is stored until immersed.
In addition, an aeration pipe 32 for aeration is provided at the bottom in the electrolysis tank 10 (activated sludge tank 30).

In the sewage treatment apparatus shown in FIG. 2, the sewage flowing into the electrolytic cell 10 which also serves as the activated sludge tank 30 is decomposed by the action of activated sludge. At the same time, this sewage is subjected to electrolysis by applying a voltage from the DC power supply 50 and supplying electricity from the anode 12 to the cathode 13 to perform electrolysis.
Aluminum ions are eluted from the electrode plate 1 serving as the anode 12 and combined with phosphate ions in the sewage to form insoluble aluminum phosphate, which is dephosphorized. The activated sludge and the precipitated aluminum phosphate are removed from the treated wastewater by the flat membrane filter 20 by the operation of the pump 41, and the treated wastewater is discharged from the drainage channel 40. As described above, this sewage treatment apparatus can purify sewage including a phosphorus component. In addition to this, the periphery of the joint between the electrode plate 1 and the current-carrying body 2 is made of aluminum by the protective film 3. Since elution is prevented and not reduced, electrolysis can be performed until the entire electrode plate 1 is consumed. Therefore, the electrode plate 1 is used efficiently without waste, resulting in a long life.

[0021]

The present invention will be described below in more detail by way of examples.

In the example, first, a processing apparatus as shown in FIG. 2 was prepared using the electrode device configured as in the above embodiment, and a durability test of the electrode device was performed. Here, the electrode plate 1
Has a size of 165 × 2 with 12 through holes 4
A 25 × 5 mm aluminum plate was used, the protective film 3 was nickel-plated, and the screw hole diameter for screwing the current-carrying body 2 made of a stainless steel rod to the upper end of the electrode plate 1 was 3 mm. Further, a filter having a pore size of 0.4 μm was used as the flat membrane filter 20. Then, a durability test was performed as follows. That is, a test wastewater to which phosphoric acid was added so as to have a total phosphorus concentration of about 5 ppm as a wastewater to be dephosphorized was prepared, and this was intermittently poured into the electrolysis total 10 at an injection rate of 13 L / day. Electrolysis at constant current (1A) 48
Min / day, and the dephosphorization treatment of
Went for months. During the 6 months, the total phosphorus concentration of the wastewater after passing through the flat membrane filter 20 was measured by IPC emission spectrometry at the beginning of the treatment and every hour thereafter for one hour before and after the electrolysis.

Next, in the case where the above-mentioned electrode plate 1 is different only in that no through-hole 4 is provided, and in the case where the protective film 3 is also different in that an epoxy resin film is used in place of nickel plating, the electrodes are similarly formed. A durability test of the apparatus was performed, and the total phosphorus concentration of the wastewater after passing through the flat membrane filter 20 for 1 hour before and after the electrolysis was measured for 6 months by IPC emission analysis at an initial stage and every month thereafter after 1 hour of electrolysis.

As a comparison with the embodiment of the present invention, a durability test of the electrode device was performed in the same manner as in the above embodiment, except that the electrode plate 1 had no through hole 4 and the protective film 3 was omitted. The total phosphorus concentration of the wastewater after passing through the flat membrane filter 20 for 1 month before and after the electrolysis was measured for 6 months by IPC emission analysis at the beginning of the start and every month thereafter.

The results are shown in Table 1 for each case.

[0026]

[Table 1]

As shown in Table 1, in the electrode device in which the protective film 3 was omitted, three months after the start of the test, aluminum was eluted at the joint portion between the electrode plate 1 and the current carrying member 2, and the bond was disengaged and the electric current was released. Decomposition was not possible and dephosphorization could not be performed. On the other hand, in the case where the protective film 3 is provided, even when either the nickel plating or the epoxy resin film is used as the protective film 3, a good phosphorus removal rate of 80% or more is obtained even after 6 months. It can be seen that the effect is obtained. Furthermore, when the through-hole 4 is provided in the electrode plate 1, a 90% dephosphorization effect is obtained even after 6 months.

[0028]

As described above, according to the electrode device of the present invention, the periphery of the joint between the current-carrying body and the electrode plate is covered with the protective film. When used as an anode in the above, the periphery of the joint between the current-carrying body and the electrode plate does not come into direct contact with water, and as a result, loss of this portion due to electrolysis is prevented. Therefore, it is possible to supply current to the electrode plate from the current-carrying body until the other parts except for the periphery of the coupling portion are reduced and lost, and the life of the electrode plate can be extended.

According to the dephosphorization apparatus of the present invention, since the electrode plate of the electrode device according to the present invention is provided as a positive electrode in the electrolytic cell to which water containing phosphate ions is supplied, a positive current is applied to the electrode plate. By conducting electricity and performing electrolysis, phosphate ions in the water in the electrification tank can be combined with metal ions eluted from the electrode plate to precipitate as insoluble metal salts, and at this time, the electrode Since the plate can be used for a long time, the frequency of replacement maintenance can be reduced.

According to the sewage treatment apparatus according to the present invention, the above-mentioned dephosphorization apparatus is used together with the activated sludge tank so that the water treated by these can be filtered by the filtration apparatus. The wastewater treatment can be carried out, and at the same time, the frequency of maintenance for replacing the electrode plate can be reduced.

[Brief description of the drawings]

FIG. 1 shows an electrode device according to an embodiment of the present invention, wherein (a) is a front view and (b) is a top view thereof.

FIG. 2 is a schematic sectional view showing an example of a dephosphorization device and a sewage treatment device using the electrode device shown in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrode plate 2 Current conductor 3 Protective film 4 Through hole 10 Electrolyzer

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[Procedure amendment]

[Submission date] April 22, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 2

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 3

[Correction method] Change

[Correction contents]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] Claim 5

[Correction method] Change

[Correction contents]

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction contents]

[0001] The present invention is, Li contained in the water of household waste water, etc.
TECHNICAL FIELD The present invention relates to an electrode device useful for removing a component by electrolysis, a dephosphorization device and a sewage treatment device using the same.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

[0009] When the electrode device of the present invention is used in a dephosphorization device that precipitates phosphate ions in water into insoluble metal salts by electrolysis, the electrode device is placed in an electrolytic cell to which water containing phosphate ions is supplied. It is preferable to provide an electrode plate as an anode . As described above, in the dephosphorization apparatus provided with the electrode plate of the electrode device of the present invention as an anode , a positive current is applied to the electrode plate to perform electrolysis, whereby phosphorus in water in the electrification tank is dissolved. Acid ions are bonded to metal ions eluted from the electrode plate and can be precipitated as insoluble metal salts.At this time, since the electrode plate can be used for a long time, the frequency of replacement maintenance is low. That's it.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0022

[Correction method] Change

[Correction contents]

In the example, first, a purification device as shown in FIG. 2 was prepared using the electrode device configured as in the above embodiment, and a durability test of the electrode device was performed. Here, the electrode plate 1
Has a size of 165 × 2 with 12 through holes 4
A 25 × 5 mm aluminum plate was used, the protective film 3 was nickel-plated, and the screw hole diameter for screwing the current-carrying body 2 made of a stainless steel rod to the upper end of the electrode plate 1 was 3 mm. Further, a filter having a pore size of 0.4 μm was used as the flat membrane filter 20. Then, a durability test was performed as follows. That is, a test wastewater to which phosphoric acid was added so as to have a total phosphorus concentration of about 5 ppm as wastewater to be dephosphorized was prepared, and this was intermittently poured into the electrolytic cell 10 at an injection rate of 13 L / day. Electrolysis at constant current (1A) 48
Min / day, and the dephosphorization treatment of
Went for months. During the 6 months, the total phosphorus concentration of the wastewater after passing through the flat membrane filter 20 was measured by ICP emission analysis for 1 hour before and after electrolysis at the beginning of the treatment and every month thereafter.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

Next, in the case where the above-mentioned electrode plate 1 is different only in that no through-hole 4 is provided, and in the case where the protective film 3 is also different in that an epoxy resin film is used in place of nickel plating, the electrodes are similarly formed. A durability test of the apparatus was performed, and the total phosphorus concentration of the wastewater after passing through the flat membrane filter 20 at the beginning of the operation and every hour thereafter was measured for 1 hour before and after the electrolysis.
It was measured by ICP emission analysis for 6 months.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction contents]

As a comparison with the embodiment of the present invention, a durability test of the electrode device was performed in the same manner as in the above embodiment, except that the electrode plate 1 had no through hole 4 and the protective film 3 was omitted. The total phosphorus concentration of the wastewater after passing through the flat membrane filter 20 for 1 hour before and after the electrolysis was measured for 6 months by ICP emission spectrometry at the initial stage and every month thereafter.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0025

[Correction method] Change

[Correction contents]

In each case, the results are shown in Table 1.
The removal rate (%) of the phosphorus component is shown in FIG .

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0029

[Correction method] Change

[Correction contents]

[0029] According to dephosphorization device of the present invention, the electrode plate of the electrode device according to the present invention in an electrolytic bath which water is supplied containing phosphate ions are provided as an anode, a positive current to the electrode plate By conducting electricity and performing electrolysis, phosphate ions in the water in the electrification tank can be combined with metal ions eluted from the electrode plate to precipitate as insoluble metal salts, and at this time, the electrode Since the plate can be used for a long time, the frequency of replacement maintenance can be reduced.

[Procedure amendment 11]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

Claims (5)

[Claims] 1. An electrode device for use in a dephosphorization apparatus for precipitating and converting phosphate ions in water into insoluble metal salts by electrolysis, comprising reacting phosphate ions with water-insoluble metal phosphate salts. An electrode plate made of a metal to be generated, and an electric conductor extending from the electrode plate and conducting to a power supply, and a protective film covering the surface is provided around a joint between the electric conductor and the electrode plate. An electrode device, characterized in that: 2. The garbage disposal apparatus according to claim 1, wherein the current-carrying body is formed of a metal having a lower ionization tendency than a metal constituting the electrode plate. 3. The garbage disposal apparatus according to claim 1, wherein at least one of a concave portion and a through hole is formed at one or more locations on the electrode plate. 4. An electrolytic cell to which water containing phosphate ions is supplied, and the electrode device according to claim 1, wherein the electrode plate is provided as an anode in the electrolytic cell. A dephosphorization device. 5. An activated sludge tank, a dephosphorization device according to claim 4, and a filtration device for filtering water treated by the activated sludge tank and the dephosphorization device. Characterized sewage treatment equipment.