JPH10328671A - Dephosphorization treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dephosphorization treatment device in which phosphorus removal is performed effectively and stably. SOLUTION: The dephosphorization treatment device D is incorporated into a miniature combined type Johkaso and equipped with an elution tank 39, iron electrodes 40, 41, a DC power source 42 and a control part 43. Iron ions reacting with phosphoric acid are eluted from the iron electrodes 40, 41 by electrolysis. The control part 43 performs control of current impressed between the electrodes 40, 41. Furthermore, an agitation mechanism 45 for agitating treatment water of the inside of the elution tank 39 is provided in the dephosphorization treatment device D. The agitation mechanism 45 prevents a reaction product formed in accordance with progress of electrolysis from being stuck on the surfaces of the electrodes 40, 41. Or, promotion of electrolytic reaction is performed by stirring up the reaction product deposited on the bottom of the elution tank 39 so that the reaction product is allowed to easily flow out of the elution tank 39.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dephosphorization treatment apparatus, and more particularly, to a phosphorous treatment apparatus incorporated in a sewage treatment apparatus such as a combined treatment septic tank for removing phosphoric acid from sewage mixed with human wastewater and domestic wastewater. To a dephosphorization treatment apparatus for performing

[0002]

2. Description of the Related Art Examples of this type of dephosphorization treatment apparatus are disclosed in JP-A-7-108296 (C02F 3/30) and JP-A-3-89998 (C02F 3/12, 1/5).
8, 11/00) is known.

The former includes an anaerobic filter bed tank or a sedimentation separation tank,
In a sewage treatment apparatus in which an aeration tank, a sedimentation tank, and a disinfection tank are arranged in this order, the sewage in the aeration tank is pumped up by a pump, and an anaerobic filter bed tank or a sedimentation tank is set through an iron dissolving apparatus having an iron electrode. This is to return to the separation tank.

[0004] The latter is provided with a liquid receiving tank such as a flow control tank or a sedimentation separation tank, a biological treatment tank, and a sludge concentration tank, and at least one of the routes from the biological treatment tank to the liquid receiving tank is provided with an insoluble phosphate. The forming metal and the noble metal are arranged in a conductive state, or a pair of insoluble phosphate forming metals are arranged and a voltage is applied between them to electrochemically form the insoluble phosphate forming metal ions. In liquid (sewage)
To remove phosphorus.

[0005]

In the former case, if the iron is eluted, a reaction product formed by the reaction between the iron and the phosphorus in the wastewater is deposited in the iron dissolving apparatus. When the deposition proceeds, the reaction product adheres to the uneluted iron, which may hinder stable elution of the iron, and there is a problem that the iron dissolving apparatus does not fulfill its original purpose of removing phosphorus.

In the latter case, metal ions dissolve into the wastewater from the insoluble phosphate-forming metal on the anode side, and react with phosphorus in the wastewater to form a reaction product. When the amount of the reaction product is large in the wastewater, there is a possibility that the stable supply of the metal ions to the wastewater may be hindered, and there is a problem that effective phosphorus removal is not performed.

[0007] The present invention has been made in view of such circumstances, and an object of the present invention is to provide a dephosphorization treatment apparatus capable of performing effective and stable phosphorus removal.

[0008]

According to the present invention, at least one pair of electrodes for eluting iron ions or aluminum ions for removing phosphoric acid in wastewater and an elution tank provided with these electrodes are provided. A dephosphorization treatment apparatus characterized by comprising a stirring mechanism for stirring sewage or treated water inside the elution tank.

[0009] At least one pair of electrodes is disposed in the elution tank,
Elutes iron ions or aluminum ions by electrolysis. Electrodes are disposed in the elution tank, and sewage to be subjected to the treatment, or sewage subjected to anaerobic / aerobic treatment, filtered, and treated water that has been subjected to a predetermined treatment is stored. These ions react with phosphoric acid (orthophosphoric acid) in wastewater to form a poorly soluble phosphorus compound (Fe (OH) _x (PO ₄ ) _y.
Alternatively, it becomes Al (OH) _x (PO ₄ ) _y ) and aggregates and precipitates. A current for electrolysis is applied between the electrodes.

[0010] The dephosphorization treatment apparatus may be provided with a control unit if desired. The control unit controls, for example, the amount of the ions eluted in the elution tank by controlling the current applied between the electrodes.

The pair of electrodes are, for example, both composed of one of iron and aluminum, or one composed of one of iron and aluminum and the other composed of an insoluble metal. In the former case, by inverting the polarity of the electrode as desired, it is possible to prevent passivation of the electrode where ion elution from the electrode does not occur. In the latter case,
An electrode composed of one of iron and aluminum is an anode, and an electrode composed of an insoluble metal is a cathode. Here, as an electrode composed of an insoluble metal,
For example, there are electrodes such as silver and platinum. A pair of electrodes is usually
It is composed of a vertically long metal plate and is disposed almost vertically inside the elution tank, but is not limited to this, and may be disposed substantially horizontally or obliquely.

This dephosphorization treatment apparatus is further provided with a stirring mechanism for stirring sewage or treated water inside the elution tank.

This stirring mechanism prevents the reaction products such as the poorly soluble phosphorus compound and metal oxide generated with the progress of electrolysis from adhering to the electrode surface, or accumulates on the bottom of the elution tank. By winding up the hardly soluble phosphorus compound or the like so as to easily flow out, the electrolytic reaction is promoted.

As the stirring mechanism, for example, a stirring rod with a propeller blade having a main part disposed inside the elution tank, a motor disposed outside the elution tank for rotating the stirring rod, and controlling the motor And a control unit for performing the operation.

[0015] For example, when a pair of electrodes are disposed almost vertically inside the elution tank, the stirring rod may be disposed substantially in the middle of these electrodes and substantially parallel to these electrodes as required by the configuration. It may be arranged at an almost middle part of these electrodes and obliquely or horizontally with respect to these electrodes.

It is preferable that the dephosphorization apparatus further includes a monitor section and a notification section. The monitor detects a stirring abnormality occurring in the stirring mechanism from a change in current or voltage of the motor. Here, the abnormal stirring is, for example, a state in which the hardly soluble phosphorus compound or the like is entangled with the stirring rod and a load of a certain value or more is applied to the driving motor. The notification unit notifies the user of the abnormal stirring. The notification unit includes, for example, at least one of a visual notification unit and an auditory notification unit.
That is, the notification unit includes both or one of a visual notification unit such as an LED lamp and an auditory notification unit such as a buzzer.

In the dephosphorization treatment apparatus configured as described above, when an agitation abnormality occurs, the control unit gives a stop instruction to the motor and a notification instruction to the notification unit based on the monitoring result from the monitor unit. To inform the user of the dephosphorization device. An administrator (such as a construction company or a maintenance company) notified by the user checks the stirring mechanism, removes the cause, performs maintenance, and the like, so that appropriate ion elution can be continued.

Preferably, the control unit instructs to turn off the power supply for electrolysis in order to stop elution of iron ions or aluminum ions by electrolysis at the same time as giving an instruction to stop the motor due to occurrence of a stirring abnormality. It is configured to

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. Note that the present invention is not limited by this.

As shown in FIG. 1, a dephosphorization treatment apparatus D according to one embodiment of the present invention is a small-sized combined treatment septic tank 1.
It is used by being incorporated in.

The inside of the septic tank 1 extends from the side of an inflow pipe 2 into which sewage mixed with human wastewater and domestic wastewater flows to the side of a discharge pipe 3 for discharging sewage-treated water to the outside.
A plurality of tanks are formed in a tank structure in accordance with the order of the sewage purification treatment.

Reference numeral 4 denotes a contaminant removal tank formed at the forefront of the inflow pipe 2. In the impurity removing tank 4, impurities that are mixed in human wastewater or domestic wastewater and cannot be purified are removed by precipitation.

An inflow guide 5 is formed on the inflow pipe 2 side of the impurity removing tank 4. Between the inflow guide 5 and the inflow pipe 2, there is formed a rectangular or cylindrical downflow passage 6 for guiding the inflow water downward of the impurity removing tank 4.

An anaerobic filter bed 7, which is a filter bed for anaerobic microorganisms, is provided in the contaminant removal tank 4. The anaerobic filter bed 7 is provided with microorganisms to perform anaerobic treatment. I have. The anaerobic filter bed 7 prevents the sediment from being lifted up by the water flow when the inflow water or backwash wastewater temporarily flows in and becomes a suspended substance and flows out to the next tank, thereby reducing the load on the next tank. Can be lowered.

Reference numeral 8 denotes the next anaerobic filter bed tank formed adjacent to the impurity removing tank 4. In the anaerobic filter bed tank 8, an anaerobic microorganism is inhabited in the anaerobic filter bed 9 to perform anaerobic treatment.

Reference numeral 10 denotes a next aerobic filter tank formed adjacent to the anaerobic filter tank 8. The aerobic filter bed tank 10 is provided with an aerobic filter bed 11, which is a filter bed for aerobic microorganisms. The aerobic filter bed 11 is provided with aerobic microorganisms so that aerobic treatment is performed. Have been.

Reference numeral 12 denotes a next settling tank formed adjacent to the aerobic filter bed tank 10. In the sedimentation tank 12, the treated water that has been subjected to aerobic treatment in the aerobic filter bed tank 10 and that has been filtered and advected is stored.

Reference numeral 13 denotes a disinfecting tank formed above the sedimentation tank 12. Usually, the disinfecting tank 13 disinfects the supernatant water after being treated in the sedimentation tank 12 and discharges it from the discharge pipe 3 to the outside.

The impurity removing tank 4 and the anaerobic filter bed tank 8 are separated by a vertical partition wall 14. In the upper part of this partition wall 14,
An advection port 15 penetrating the partition wall 14 is formed.
A square or cylindrical advection tube 16 is fitted into the advection port 15. The lower end of the advection pipe 16 is located below the anaerobic filter bed 7 of the impurity treatment tank 4,
Also serves as a cleaning port.

The anaerobic filter tank 8 and the next aerobic filter tank 10 are separated by an intermediate partition 17. An upflow passage 18 is fixedly provided on the anaerobic filter bed tank 8 side of the intermediate partition wall 17.

The sewage that has been transferred from the impurity removing tank 4 to the anaerobic filter bed tank 8 through the convection pipe 16 passes through the anaerobic filter bed 9 in a descending flow, and then rises through the upflow passage 18 to be good. It flows into the filter bed tank 10.

The anaerobic filter bed 9 in the anaerobic filter tank 8 captures some suspended solids (SS). SS captured
Is gradually dissolved anaerobically and becomes soluble, or is stored as sludge at the bottom of the anaerobic filter tank 8.
In the anaerobic filter bed 9, organic nitrogen is anaerobically decomposed into ammonia nitrogen.

In the vicinity of the bottom of the aerobic filter bed tank 10, an air diffuser 22 of an air diffuser 21 is disposed horizontally. The air diffuser 21 has a function of supplying oxygen to the aerobic microorganisms that inhabit the aerobic filter bed 11 of the aerobic filter bed tank 10 by blowing out air from the diffuser pipe 22.

A filter medium is disposed on the aerobic filter bed 11 in the aerobic filter bed tank 10.
The OD component and the like are decomposed or made into SS, and captured by the filter medium. The aerobic filter bed tank 10 also has a physical filtration action,
Here, SS is also captured. In the aerobic filter bed tank 10,
The action of nitric acid bacteria and nitrites that convert nitrogen to nitric acid converts ammoniacal nitrogen to nitrate nitrogen.

A partition 23 is provided between the aerobic filter bed tank 10 and the next settling tank 12. A communication part 24 is provided below the partition 23. And this communication part 24
Thereby, the aerobic filter bed tank 10 and the sedimentation tank 12 communicate with each other.

In the sedimentation tank 12, the treated water flowing from the aerobic filter bed tank 10 through the communication part 24 is separated into a sediment and a supernatant water. The bottom of the sedimentation tank 12 is used to return the sediment deposited there to the aerobic bed tank 10 through the communication part 24.
The structure is inclined at a certain angle.

The bottom of the aerobic filter tank 10 and the upper part of the impurity removing tank 4 are communicated by an L-shaped first return pipe 25 composed of a vertical portion 25a and a horizontal portion 25b. 1st return pipe 2
The first air supply pipe 31a is disposed inside the vertical portion 25a of the fifth air supply device. The first air supply pipe 31a is connected to the air lift pump 2
9 is connected to a blower 30 outside the tank via an air lift supply pipe 31. Then, by blowing out the air supplied from the blower 30 from the first air supply pipe 31a, the sludge accumulated at the bottom of the aerobic filter bed tank 10 is sucked into the first return pipe 25 and returned to the impurity removing tank 4. It has become.

On the other hand, the supernatant water of the treated water in the sedimentation tank 12 is pumped up from the lift pipe 32 by the air that is disposed inside the lift pipe 32 and is blown out from the second air supply pipe 31 b communicating with the air supply pipe 31. The first air supply pipe 31a and the second air supply pipe 31b can be switched to either one by a switching valve.

A circulation path 26 is provided from the upper part of the settling tank 12 to the upper part of the impurity removing tank 4 for constantly returning the supernatant water of the treated water. The circulation path 26 is provided with a water separation measuring device 27, a dephosphorization treatment device D, and an inlet 28 to the impurity removing tank in the order of water flow from the sedimentation tank 12. Then, the supernatant water pumped up from the lift pipe 32 is returned to the upper part of the downflow passage 6 of the impurity removing tank 4 via the circulation path 26 after passing through the water separation measuring device 27 and the dephosphorization treatment device D. .

The water dividing and measuring device 27 is installed on the upper part of the sedimentation tank 12 and is integrally formed with a front / rear plate, left and right side plates and a bottom plate into a rectangular box-shaped bottomed structure. The inside of the box is divided into an inflow chamber, a water separation chamber, and an intermediate chamber between the two.

The inflow chamber is provided with an inflow pipe through which the supernatant water drawn from the lift pipe 32 of the air lift pump 29 flows. The inflow chamber and the intermediate chamber are separated from each other by a partition having an opening formed so that the lower side can communicate with each other, so that the treated water flowing into the inflow chamber is made to submerge and flow to the intermediate chamber.

The water diversion chamber is composed of a first water diversion chamber and a second water diversion chamber.
It is divided into rooms. The partition between the first water diversion chamber and the intermediate chamber has a lower end fixed to the bottom plate and an upper end opened in a V-shape. The partition between the second water diversion chamber and the intermediate chamber has a lower end fixed to the bottom plate and an upper end opened in a concave shape. An overflow weir plate whose opening size can be adjusted is attached to the partition wall opened in the concave shape.

An outflow pipe for discharging the treated water to the circulation passage 26 is connected to the first water separation chamber, and an outlet pipe for discharging the treated water to the aerobic filter bed tank 10 is connected to the second water separation chamber. Outflow pipe is connected. Therefore, the treated water flowing into the inflow chamber is
Through the intermediate chamber, water is divided into the circulation path 26 and the aerobic filter bed tank 10 in two water dividing chambers by adjusting the height of the overflow weir plate.

As shown in FIG. 2 in an enlarged manner, the dephosphorization treatment apparatus D comprises an elution tank 39 and a pair (a pair) of rectangular plate-like iron electrodes disposed almost vertically inside the elution tank 39. 40 ・
41, an electrolysis DC power supply 42 for supplying a current between these electrodes 40, 41, a control unit 43, and a switch 4
4 is provided. The electrodes 40 and 41 use iron for both the anode and the cathode.

In the elution tank 39, treated water flowing out of the outflow pipe 37 is stored. One set of iron electrodes 40 and 41 elutes iron ions that react with phosphoric acid by electrolysis. The controller 43 controls the amount of the ions eluted in the elution tank 39 by controlling the current applied between the electrodes 40 and 41.

The elution tank 39 is provided above the aerobic filter bed tank 10 and is integrally formed of a front / back plate portion, left and right side plate portions and a bottom plate portion into a rectangular box-shaped bottomed structure. I have. Positive
The back plate portion is provided with an inflow pipe portion and an outflow pipe portion, respectively.

As shown in FIG. 2, the elution tank 39 is provided with a stirring mechanism 45 for stirring the treated water in the elution tank 39.

The stirring mechanism 45 prevents the reaction products such as the poorly soluble phosphorus compound and metal oxide generated as the electrolysis proceeds from adhering to the surfaces of the electrodes 40 and 41, or provides a dissolution tank. By winding up the reaction product deposited on the bottom of 39 so as to easily flow out of the elution tank 39,
This is for promoting the electrolytic reaction.

The stirring mechanism 45 includes a stirring rod 46 with a propeller blade, the main part of which is disposed inside the elution tank 39, and the elution tank 3.
9 is provided with a DC motor 47 for driving the stirring rod 46 to rotate, and a control unit 43 for controlling the motor 47.

The stirring rod 46 is disposed substantially in the middle of the pair of electrodes 40 and 41 and substantially parallel to the electrodes 40 and 41, and the propeller blade 46a is located slightly below the lower end of the electrodes 40 and 41. ing. Then, the water is rotated at a predetermined rotation speed by the motor 47 to stir the treated water inside the elution tank 39.

The dephosphorization apparatus D is further provided with a characteristic monitor section 48 and a notifying section 49. The monitor section 48 is a part of the control section 43 and includes a stirring mechanism 45.
Is detected from a change in the current or voltage of the motor 47. Here, the stirring abnormality refers to a state in which the hardly soluble phosphorus compound or the like is entangled with the stirring rod 46 and a load of a certain value or more is applied to the motor 47. The notifying unit 49 includes an LED lamp as a visual notifying unit, and notifies an abnormal stirring.

In the dephosphorization treatment apparatus D configured as described above, when an agitation abnormality occurs, the control unit 43 gives a stop instruction to the motor 47 based on the monitoring result from the monitor unit 48, and also notifies the notification unit 49. A notification instruction is given to notify the user of the dephosphorization treatment device D. Managers (such as contractors and maintenance managers) who have been contacted by this user
By inspecting the stirring mechanism 45 and removing the cause or performing maintenance, appropriate ion elution can be continued.

The control unit 43 determines that the motor 4
In order to stop the elution of iron ions by electrolysis at the same time as giving an instruction to stop to 7, the power supply 42 is instructed to be turned off.

This will be described in more detail with reference to FIG. The processing water storage volume of the elution tank 39 is 500 ml. The flow rate of the treated water flowing into the elution tank 39 is set to 0.5 L / min, and the phosphate ion concentration is set to 15 mg / L (5 mg / L for the total phosphorus concentration T-P). When the treated water flows into the elution tank 39, the electrodes 40, 41
And the stirring rod 46 is rotated by the motor 47 to stir the treated water in the elution tank 39 (ST).
ART).

In normal operation, the molar ratio is Fe / P = 1.0
Apply a current (constant current) to the electrodes 40 and 41 so that
Flow. In one example, the current is 3 when Fe / P = 1.5.
Flow 81 mA. The current (initial current) supplied to the motor 47 at this time is measured by the monitor unit 48.

After a predetermined time has elapsed, the current supplied to the motor 47 at that time is measured again by the monitor unit 48. The measured current value is defined as A.

If the stirring bar 46 does not rotate sufficiently even though the motor 47 is turned on, the reaction product accumulates in the elution tank 39 or the surface of the electrodes 40 and 41. Therefore, stable elution of iron ions cannot be continued.

Therefore, the current value A is equal to the initial current value of 1.
If it exceeds five times, the control unit 43 determines that the stirring is abnormal, gives a stop instruction to the motor 47, and sets the O
Specify FF. The control unit 43 also gives an instruction to the notifying unit 49 and turns on the LED lamp to notify the user (warning).

On the other hand, the current value A is 1.5 times the initial current value.
If it is less than twice, the electrodes 40 and 41 are usually electrolyzed, but when a compound that cannot be removed by stirring with the stirring rod 46 adheres to the surfaces of the electrodes 40 and 41, that is, the electrodes 40 and 41 passivate. In the event that the electrode 40
If 41 is worn out and becomes smaller, the current density may become too large and the voltage may become larger than the normal value. If the voltage applied between the electrodes 40 and 41 exceeds 25 V, there is a risk of electric shock or the like.
3 may be configured to stop the electrolytic reaction with the upper limit of 25 V.

In the elution tank 39, iron ions Fe ²⁺ are dissolved from the electrodes 40 and 41, and oxygen is supplied to the treated water by the aeration tube 45. Fe ²⁺ is oxidized by using dissolved oxygen to be Fe ³⁺ and sent to the impurity removing tank 4, where it reacts with orthophosphoric acid PO ₄ ^3- to form a hardly soluble iron phosphate Fe 2+.
(OH) _x (PO ₄ ). The iron phosphate Fe (OH) _x (PO ₄ ) agglomerates around the SS present in the contaminant removal tank 4, forms large flocs, precipitates and deposits on the bottom of the tank.

The contaminants deposited on the bottom of the contaminant removal tank 4 and containing dephosphorized sludge are removed from the anaerobic filter bed 7 in the contaminant removal tank 4.
It is regularly pumped from vacuum-free areas by vacuum cars (usually at a rate of about once a year).

[0062]

According to the first aspect of the present invention, at least one pair of electrodes for eluting iron ions or aluminum ions for removing phosphoric acid in wastewater, and an elution tank provided with these electrodes are provided. And a stirring mechanism for stirring sewage or treated water inside the elution tank. Therefore, the stirring mechanism prevents reaction products such as poorly soluble phosphorus compounds and metal oxides generated with the progress of electrolysis from adhering to the electrode surface, or reaction products deposited on the bottom of the elution tank. The effect of promoting the electrolytic reaction is obtained by winding up so as to easily flow out.

According to the second aspect of the present invention, the stirrer is provided with a stirring rod with a propeller blade having a main portion disposed inside the elution tank, and a stirring rod disposed outside the elution tank for rotating the stirring rod. And a control unit for controlling the motor. Therefore, it is possible to secure the effects of the invention described in claim 1 with a simple configuration and with inexpensive members.

According to the third aspect of the present invention, the pair of electrodes are disposed substantially vertically inside the elution tank, and the stirring rod of the stirring mechanism is disposed substantially in the middle of these electrodes and substantially parallel to these electrodes. Therefore, the effect of the invention described in claim 2 can be secured with a simple configuration.

According to the fourth aspect of the present invention, the pair of electrodes are disposed substantially vertically inside the elution tank, and the stirring rod of the stirring mechanism is positioned substantially in the middle of these electrodes and obliquely with respect to these electrodes. Or because it is arranged in the horizontal direction,
Even when it is not possible to dispose the stirring rod substantially parallel to the electrode due to the restriction on the configuration, the effect of the invention described in claim 2 can be secured with a simple configuration.

According to the fifth aspect of the present invention, there is further provided a monitor for detecting a stirring abnormality occurring in the stirring mechanism from a change in current or voltage of the motor, and a notifying section for notifying the stirring abnormality. When an abnormal stirring occurs, the control unit gives a stop instruction to the motor and a notification instruction to the notification unit based on the monitoring result from the monitor unit. Therefore, when a stirring abnormality occurs, the control unit gives a stop instruction to the motor and also gives a notification instruction to the notification unit to notify the user, and the administrator who is notified by the user checks the stirring mechanism. Proper ion elution can be continued by removing the cause or performing maintenance.

According to the sixth aspect of the present invention, since the notifying section is composed of at least one of the visual notifying section and the auditory notifying section, if an agitation abnormality occurs, the notifying section will visually and / or auditoryly. Information is now available,
The effect achieved by the invention described in claim 5 can be ensured by a simple configuration.

[Brief description of the drawings]

FIG. 1 is a vertical longitudinal sectional view of a small-sized combined treatment septic tank incorporating a dephosphorization treatment apparatus according to one embodiment of the present invention.

FIG. 2 is an enlarged vertical cross-sectional view of a part of the phosphorus removal treatment apparatus of FIG.

FIG. 3 is a flowchart illustrating an operation of the dephosphorization processing apparatus of FIG. 1;

[Explanation of symbols]

 39 Elution tank 40 Electrode 41 Electrode 42 Power supply 43 Control unit 45 Stirring mechanism 46 Stirring rod 46a Propeller blade 47 Motor 48 Monitor 49 Notification unit

Claims (6)

[Claims] 1. An apparatus comprising: at least one pair of electrodes for eluting iron ions or aluminum ions for removing phosphoric acid in sewage; and an elution tank provided with these electrodes.
Further, a dephosphorization treatment device comprising a stirring mechanism for stirring sewage or treated water inside the elution tank. 2. A stirring mechanism includes: a stirring rod with a propeller blade having a main part disposed inside an elution tank; a motor disposed outside the elution tank for rotating the stirring rod; and controlling the motor. The dephosphorization treatment apparatus according to claim 1, further comprising a control unit for performing the treatment. 3. The elution tank according to claim 2, wherein the pair of electrodes are disposed substantially vertically inside the elution tank, and the stirring rod of the stirring mechanism is disposed substantially in the middle of the electrodes and substantially parallel to the electrodes. Dephosphorization equipment. 4. A pair of electrodes are disposed substantially vertically inside the elution tank, and a stirring rod of a stirring mechanism is disposed substantially in the middle of these electrodes and obliquely or horizontally with respect to these electrodes. The dephosphorization treatment apparatus according to claim 2, wherein 5. A stirrer further comprising: a monitor unit for detecting a stirrer abnormality occurring in the stirrer mechanism from a change in current or voltage of the motor; and a notifying unit for notifying the stirrer abnormality. 3. The dephosphorization treatment apparatus according to claim 2, wherein the control unit gives a stop instruction to the motor and gives a notification instruction to the notification unit based on the monitoring result from the monitoring unit. 6. The dephosphorization processing device according to claim 5, wherein the notifying unit comprises at least one of a visual notifying unit and an auditory notifying unit.