JPH10263552A - Sewage treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewage treating device capable of preventing explosion in maintenance or the like and improving reliability. SOLUTION: Current value applied to an electrode 12 in a elution vessel 8 provided in a treating vessel 1 having an anaerobic part 5, an aerobic part 22 and a settling part 28 is detected and a control means 57 for controlling the quantity of air to be supplied to the sewage in the elusion vessel 8 based on the detected current value is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sewage treatment apparatus for purifying sewage, and more particularly to a sewage treatment apparatus for removing phosphorus from sewage.

[0002]

2. Description of the Related Art As a sewage treatment apparatus of this kind, sewage in an aerobic tank is returned to an anaerobic tank via an elution device for eluting iron ions, and the iron ions are reacted with orthophosphoric acid in the sewage to make water insoluble. As a phosphorus compound, one that coagulates and precipitates and removes phosphorus from wastewater is known.

[0003] However, if hydrogen gas generated from the electrode due to electrolysis of the electrode accumulates in the elution tank and fire is accidentally approached during maintenance or the like, there is a risk of explosion.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a sewage treatment apparatus capable of preventing explosion at the time of maintenance or the like and improving reliability. Make it an issue.

[0005]

A first means for solving the above-mentioned problems is to apply a current to a treatment tank having an anaerobic part, an aerobic part and a sedimentation part, and to apply an electric current to an electrode made of iron material or aluminum. An elution tank for eluting ions or aluminum ions, a diffuser pipe disposed in the elution tank and supplying air to sewage in the elution tank, and a treatment tank for treating iron ions or aluminum ions eluted in the elution tank. Supply means for supplying sewage in the effluent tank, and means for setting an air supply amount to the sewage water in the elution tank according to a total current value applied to the electrode.

[0006] A second means for solving the above problems is as follows.
A treatment tank having an anaerobic part, an aerobic part and a sedimentation part; an elution tank for applying an electric current to an electrode made of iron or aluminum to elute iron ions or aluminum ions; and an elution tank disposed in the elution tank. A diffuser pipe for supplying air into the wastewater in the vessel, and a supply unit for supplying iron ions or aluminum ions eluted in the elution tank to the wastewater in the treatment tank, and a total current value applied to the electrode is provided. Control means for detecting and controlling the amount of air supplied to the wastewater in the elution tank based on the detected total current value is provided.

[0007] A third means for solving the above problems is as follows.
A treatment tank having an anaerobic part, an aerobic part, and a sedimentation part, an elution tank for applying an electric current to an electrode made of iron material or aluminum to elute iron ions or aluminum ions, and a diffuser tube provided in the elution tank A blower connected to the diffuser pipe and supplying air to the wastewater in the elution tank via the diffuser pipe; and supplying iron ions or aluminum ions eluted in the elution tank to the wastewater in the treatment tank. Supply means, and a control means for detecting a total current value applied to the electrode, and supplying air represented by the following formula A to the sewage in the elution tank based on the detected total current value. It is characterized by the following.

[0008]

(Equation 2)

In the first to third means,
Preferably, a constant DC current is applied to the electrode.

In the first to third means,
It is preferable to apply a DC constant current for changing the polarity every predetermined time to the electrode.

In the first to third means,
It is preferable to apply a DC current in which the applied current increases in a pulsed manner every predetermined time to the electrode.

In the first to third means,
It is preferable to apply a direct current whose polarity is changed every predetermined time and whose applied current increases in a pulsed manner to the electrode.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described in detail below based on a sewage treatment apparatus shown in FIGS.

Reference numeral 1 denotes a treatment tank buried underground. The inside of the processing tank 1 is divided into first anaerobic section 5, second anaerobic section 18, aerobic section 22, sedimentation section 28, and disinfecting section by a first partition 2, a second partition 3 and a third partition 4. It is divided into 30.

Reference numeral 5 denotes a first anaerobic section having an inflow port 6 into which miscellaneous wastewater flows, and reference numeral 7 denotes a first anaerobic filter bed disposed in the first anaerobic section 5, which flows into the first anaerobic section 5. Sedimentation and separation of the hardly decomposable impurities mixed in the wastewater, and the anaerobic microorganisms attached to the first anaerobic filter bed 7 anaerobically decompose the organic substances and convert the organic nitrogen into ammonia nitrogen. Anaerobic decomposition.

Reference numeral 8 denotes a rectangular box-shaped elution tank disposed above the sewage of the first anaerobic section 5 and facing a first inspection opening 49 described later. The treated water supplied from the water separation measuring device 39 via the first anaerobic section 5
And a discharge pipe 9 for returning to the main body. Reference numeral 10 denotes an exhaust port provided above the elution tank 8 for discharging air from the elution tank 8.

Reference numeral 11 denotes an electrode cover having an electrode 12 made of an iron material disposed in the elution tank 8 and formed of an insulator for closing the elution tank 8. Reference numeral 13 denotes a power supply device which is controlled by a control circuit 57 to be described later and applies a DC constant current between the electrodes 12, and elutes from the electrode 12 by applying a DC constant current supplied from the power supply device 13 between the electrodes 12. The supplied iron ions are supplied into the elution tank 8. The elution tank 8, the electrodes 12 and the power supply device 13 constitute an elution device.

Reference numeral 14 denotes a first air diffuser disposed between the electrodes 12 at the bottom of the elution tank 8, which forms a number of air outlets and is connected to the first blower 15. By discharging the supplied air from the air outlet, the electrode 12 is washed and sludge is prevented from adhering, and divalent iron ions eluted from the electrode 12 react with orthophosphoric acid.
Oxidizes to monovalent iron ions.

Reference numeral 16 denotes a first anaerobic section 5 provided in the first anaerobic section 5.
The treated water decomposed anaerobically in the first anaerobic section 5 is supplied to a second anaerobic section 18 to be described later through a first water supply port 17 penetrating the upper part of the first partition wall 2 by an advection pipe.

Reference numeral 18 denotes a first anaerobic section 5 formed by the first partition wall 2.
The second anaerobic section 19 is a second anaerobic filter bed disposed in the second anaerobic section 18. The second anaerobic filter bed 19 captures suspended matter and removes organic matter by anaerobic microorganisms. It anaerobically decomposes organic nitrogen into ammonia nitrogen while anaerobically decomposing.

Reference numeral 20 denotes a second anaerobic section 18 provided in the second anaerobic section 18.
The treated water decomposed anaerobically in the second anaerobic section 18 is supplied to the aerobic section 22 to be described later through an advection pipe through a second water supply port 21 penetrating the upper part of the second partition wall 3. Reference numeral 22 denotes an aerobic section defined by the second partition wall 3 as a second anaerobic section 18.
The anaerobic treated water flows in through the second advection pipe 20. Reference numeral 23 denotes a contact material provided in the aerobic part 22, which promotes the culture of aerobic microorganisms.

Reference numeral 24 denotes a second air diffuser disposed at the bottom of the aerobic section 22. The second air diffuser forms a number of air outlets and is connected to the second blower 25 to supply air supplied from the second blower 25. The air is discharged from the air outlet to maintain the inside of the aerobic part 22 in an aerobic state, and the treated water is aerobically decomposed by aerobic microorganisms,
Ammonia nitrogen is decomposed into nitrate or nitrite nitrogen by the action of nitrate or nitrite.

Reference numeral 26 denotes a third air diffuser disposed below the contact member 23 and having a large number of air outlets.
Is connected to The air supply from the second blower 25 can be switched to either the second diffuser 24 or the third diffuser 26 by a first solenoid valve 27 controlled by a control circuit 57 described later.

The first solenoid valve 27 normally switches to the second air diffuser 24 and discharges the air supplied from the second blower 25 from the air outlet of the second air diffuser 24 to improve the inside of the aerobic section 22. When the contact material 23 is cleaned, the air supply from the second blower 25 is switched to the third air diffuser 26 and the third air diffuser 26 is maintained.
Air is discharged from the air outlet of the biofilm, and the biofilm that has adhered to the contact material 23 and multiplied and gradually thickened is peeled off.

Reference numeral 28 denotes a sedimentation section defined by the third partition wall 4 and the aerobic section 22. The sedimentation section 28 is provided at the bottom of the third partition wall 4 and flows in from a communication port 29 for communicating the aerobic section 22 and the sedimentation section 28. Then, the treated water aerobically decomposed in the aerobic part 22 is separated into a precipitate and a supernatant. Further, in order to return the sediment deposited on the bottom of the sedimentation part 28 to the aerobic part 22 from the communication port 29, the bottom part of the sedimentation part 28 is aerobic part.
It is inclined to 22 side.

Reference numeral 30 denotes a disinfecting section provided above the settling section 28,
The supernatant separated in the precipitation section 28 flows in. Reference numeral 31 denotes a sterilizing device provided in the disinfecting unit 30. The disinfecting unit 30 is provided by a chlorine-based chemical or the like provided in the sterilizing device 31.
Disinfect the treated water that has flowed into the facility. Reference numeral 32 denotes a drain port communicating with the disinfecting section 30 for draining treated water disinfected in the disinfecting section 30 out of the treatment tank 1.

Reference numeral 33 denotes a first return pipe communicating the bottom of the aerobic section 22 and the top of the first anaerobic section 5. Reference numeral 34 denotes a fourth air diffuser disposed in the first return pipe 33 at the bottom of the aerobic section 22. The fourth air diffuser forms a number of air outlets and is connected to the third blower 35.
By discharging the air supplied from the third blower 35 from the air outlet, the sludge deposited on the bottom of the aerobic part 22 and the sediment returned to the aerobic part 22 from the sedimentation part 28 are transferred to the first return pipe. The air is sucked into 33 and returned to the first anaerobic section 5.

Reference numeral 36 denotes a second return pipe which communicates the upper part of the sedimentation section 28 with an inflow chamber 40 of a water distribution measuring device 39 described later. Reference numeral 37 denotes a fifth air diffuser disposed in the second return pipe 36, which forms a number of air outlets and is connected to the third blower 35. The air supply from the third blower 35 can be switched to either the fourth diffuser 34 or the fifth diffuser 37 by a second solenoid valve 38 controlled by a control circuit 57 described later.

Normally, the second solenoid valve 38 switches to the fifth air diffuser 36 and discharges the air supplied from the third blower 35 from the air outlet of the fifth air diffuser 36 to thereby settle the sedimentation section 28.
The supernatant liquid therein is sucked into the second return pipe 36 and transferred to the inflow chamber 40 of the water distribution measuring device 39 described later.

After cleaning the contact material 23, the air supply from the third blower 35 is switched to the fourth air diffuser 34, and the air is discharged from the air outlet of the fourth air diffuser 34 so that the aerobic part 22 is removed. The treated water flows through the first return pipe 33 into the first anaerobic bed tank 5. The sludge deposited at the bottom of the aerobic part 22 and the sediment returned to the aerobic part 22 from the sedimentation part 28 with this flow
It is sucked into the return pipe 33 and returned to the first anaerobic section 5.

Numeral 39 denotes a rectangular box-shaped water measuring device arranged above the sedimentation section 28, which can adjust the amount of the supernatant liquid transferred by the second return pipe 36 to the elution tank 8 to a predetermined amount. It has become. The water metering device 39 includes an inflow chamber 40 connected to the second return pipe 36, an intermediate chamber 42 partitioned by a partition wall 41 having an opening communicating with the inflow chamber 40 and a lower side, and an intermediate chamber 42. It is divided into a first water separation chamber 43 and a second water separation chamber 44 into which the treated water flows.

The first water separation chamber 43 is connected to the elution tank 8 by a third return pipe.
45, and the upper part of the wall is
They communicate with each other through cutouts 46 which are open in a letter shape. The second
The water dividing chamber 44 communicates with the upper part of the aerobic part 22 by a pipe 47, and communicates with the intermediate chamber 42 by an opening formed at the upper part of an overflow weir plate 48 whose height can be adjusted.

The height of the overflow weir 48 is adjusted, and the overflow weir 48 is adjusted.
The size of the opening formed in the upper part of the
By setting the amount of treated water to be returned to the aerobic section 22, the amount of treated water flowing into the elution tank 8 from the first water separation chamber 43 can be adjusted.

Reference numeral 49 denotes a first inspection opening provided at a position facing the first anaerobic section 5, the second anaerobic section 18 and the elution tank 8 above the first partition wall 2, and 50 denotes the first inspection opening. A reed switch provided at 49 detects an open / closed state of a first lid 51 described later. 51 is a first lid for closing the first inspection opening 49 so that it can be opened and closed, and 52 is the first lid.
51 is a magnet provided on 51 and for turning on and off the reed switch 50. The first lid 51 is positioned by positioning means (not shown) such that the magnet 52 provided on the first lid 51 faces the reed switch 50.

The first lid 51 is used to remove the sludge deposited on the bottoms of the first anaerobic section 5 and the second anaerobic section 18 by suction and to remove the electrode of the elution tank 8.
It opens and closes at the time of maintenance of 12, etc. When the first cover 51 is opened, the reed switch 50 is turned off, and based on this signal, the control circuit 57 stops only the power supply 13 and activates the power supply 13 when the first cover 51 is attached.

Reference numeral 53 denotes a second inspection opening provided at a position facing the aerobic portion 22, and reference numeral 54 denotes a second lid for closing and opening the second inspection opening 53 in an openable and closable manner. Reference numeral 55 denotes a third inspection opening provided at a position facing the sterilization device 31, and reference numeral 56 denotes a third lid body that closes the third inspection opening 55 so as to be openable and closable. It opens and closes when refilling.

Reference numeral 57 denotes the first blower 15 and the second blower 2
5, a control circuit for controlling the third blower 35, the power supply device 13, the first solenoid valve 27, the second solenoid valve 38, and the like.

The household wastewater discharged from the household flows into the first anaerobic section 5 through the inlet 6. The first anaerobic filter bed 7 disposed in the first anaerobic section 5 removes relatively coarse solids and contaminants such as toilet paper in household wastewater, and removes them in each treatment tank flowing in later. Preliminary treatment for smooth treatment is performed, and at the same time, the removed solids, contaminants, and sewage passing through the first anaerobic filter bed 7 are anaerobically decomposed by the action of anaerobic microorganisms, and the BOD is reduced. Sludge generated by the decomposition of the sewage accumulates at the bottom of the first anaerobic section 5. It also anaerobically decomposes organic nitrogen into ammonia nitrogen.

The treated water that has been anaerobically decomposed in the first anaerobic section 5 by the new domestic wastewater that flows into the first anaerobic section 5
It flows into the second anaerobic section 18 from the first water supply port 17 of the advection pipe 16.
The treated water that has flowed into the second anaerobic section 18 anaerobically decomposes organic substances by the action of anaerobic microorganisms in the second anaerobic filter bed 19 to reduce BOD, and sludge generated by the decomposition of sewage is treated in the second anaerobic section. 18 Deposit on the bottom. It also anaerobically decomposes organic nitrogen into ammonia nitrogen.

The treated water anaerobically decomposed in the second anaerobic filter bed 19 by the new treated water flowing into the second anaerobic section 18 is supplied to the second advection pipe.
20 flows into the aerobic part 22 from the second water supply port 21. The treated water that has flowed into the aerobic part 22 is stirred by the air supplied from the second blower 25 being discharged from the air outlet of the second air diffuser 24.

Further, oxygen is dissolved in the treated water, and the treated water is aerobically decomposed by the action of a large number of aerobic microorganisms attached to the surface of the contact material 23, and organic phosphates and the like are decomposed into orthophosphoric acid, and ammonia Decomposes nitrogen into nitrate and nitrite nitrogen. Further, the sludge generated by the decomposition of the sewage accumulates on the bottom of the aerobic part 22.

The freshly treated water flowing into the aerobic part 22 causes the treated water aerobicly decomposed by the action of the aerobic microorganisms attached to the contact material 23 to flow from the communication port 29 at the bottom of the aerobic part 22 to the sedimentation part.
Flow into 28. The treated water flowing into the sedimentation section 28
While rising inside, the sedimentable substance sinks and is returned to the aerobic part 22 from the communication port 29, and the supernatant flows into the disinfecting part 30. The supernatant liquid that has flowed into the disinfecting section 30 is disinfected by a disinfecting device 31 equipped with a chlorine-based chemical and kills bacteria such as pathogenic bacteria,
The water is drained out of the treatment tank 1 from the drain port 32.

The air supplied from the third blower 35 is
By discharging from the air outlet of the diffuser 37, the sedimentation
The supernatant liquid in 28 flows into the inflow chamber 40 of the water separation measuring device 39,
The water is rectified in the intermediate chamber 42 and flows into the first water separation chamber 43 and the second water separation chamber 44.

The height of the overflow weir plate 48 is adjusted, and the second water diversion chamber 44 is adjusted.
By changing the size of the opening formed above the overflow weir plate 48 that communicates with the intermediate chamber 42, the amount of water returned from the second water separation chamber 44 to the aerobic section 22 is determined. The amount of treated water flowing into the elution tank 8 from the water chamber 43 can be adjusted to a predetermined amount.

The treated water flowing into the elution tank 8 from the first water separation chamber 43 via the third return pipe 45 is supplied with iron which elutes from the electrode 12 by applying a DC constant current between the electrodes 12 made of iron material. Ions are supplied. The eluted iron ions react with orthophosphoric acid present in the elution tank 8, aggregate and precipitate as a water-insoluble phosphorus compound, and are returned to the first anaerobic section 5 through the discharge pipe 9. The iron ions in the treated water returned to the first anaerobic section 5 react with orthophosphoric acid present in the first anaerobic section 5 and aggregate and precipitate as a water-insoluble phosphorus compound.

The nitrate and nitrite nitrogen in the treated water returned to the first anaerobic section 5 is reduced by the denitrifying bacterium abundantly present in the first anaerobic section 5 and diffused into the air as nitrogen gas. Removed.

The treated water returned from the elution tank 8 to the first anaerobic section 5 is supplied not from the aerobic section 22 where the dissolved oxygen concentration is extremely high, but from the sedimentation section 28. Even if the treated water is returned to the first anaerobic section 5, anaerobic treatment can be performed with little influence on anaerobic microorganisms.

Since the biofilm formed by the aerobic microorganisms attached to the contact material 23 grows and gradually becomes thicker, the control circuit 57 controls the first solenoid valve 27 periodically to prevent clogging. The air supply from the second blower 25 is switched to the third air diffuser 26, and air is released from the air outlet of the third air diffuser 26 to peel off the biofilm.

When the supply of air from the third air diffuser 26 is completed, the separated biofilm is deposited on the bottom of the aerobic part 22, but the control circuit 57 controls the second solenoid valve 38 to transmit the air from the third blower 35. By switching the air supply to the fourth air diffuser 34 and discharging air from the air outlet of the fourth air diffuser 34, the treated water in the aerobic part 22 is discharged through the first return pipe 33 to the first anaerobic part. Flow into 5. With this flow, the sludge deposited at the bottom of the aerobic section 22 and the sediment returned from the sedimentation section 28 to the aerobic section 22 are returned to the first anaerobic section 5 via the first return pipe 33.

The elution tank 8 is disposed so as to face the first inspection opening 49. The first lid 51 is opened to open the first anaerobic section 5 and the second anaerobic section 5.
The elution tank 8 is used for removing sludge accumulated in the anaerobic part 18 by suction.
Can be checked. Further, when the first lid 51 is opened, the control circuit 57 stops only the power supply device 13 and continuously operates the devices other than the power supply device 13, so that the operation of the sewage treatment device and the sewage treatment status are confirmed. And electric shock during maintenance of the elution tank 8 can be prevented.

The amount of hydrogen gas generated from the electrode 12 by electrolysis of the electrode 12 in the elution tank 8 is determined according to Faraday's law.
For example, if the current value applied to the electrode 12 is B ampere,
The amount A (liter) of hydrogen gas generated per minute is expressed by the following equation in a standard state (20 degrees Celsius, 1 atm).

[0052]

(Equation 3)

Since the explosion concentration of hydrogen gas is 4 to 75%, the concentration of hydrogen gas in the elution tank 8 is reduced to less than 4% by the air supplied from the first blower 15 through the first diffuser 14. The minimum amount of air supply V (liter) required for one minute to perform the operation is expressed by the following equation.

[0054]

(Equation 4)

Accordingly, by controlling the amount of air supplied to the first blower 15, the control circuit 57 supplies the first blower with more air than the amount of air supplied calculated from the above relational expression V = 0.168B (liter / minute). By supplying the gas from −15 to the elution tank 8 through the first diffuser 14, the hydrogen gas in the elution tank 8 can be reduced to a concentration lower than the explosion concentration, and the explosion can be prevented.

Further, the amount of phosphorus flowing into the sewage treatment apparatus is substantially determined by the number of people living in the house, and the current value applied to the electrode 12 to elute iron ions corresponding to the flowed phosphorus is determined. Therefore, the construction operator selects and installs the first blower 15 having the optimum air supply amount according to the current value applied to the electrode 12, or the first blower 15 according to the current value applied to the electrode 12. The air supply amount may be adjusted to prevent explosion due to hydrogen.

Further, when a plurality of electrodes are provided in the elution tank 8, the required amount of hydrogen gas is calculated based on the hydrogen gas generation amount calculated with respect to the total current value obtained by summing the current values applied to each electrode. What is necessary is just to supply air.

Although hydrogen gas lighter than air is likely to accumulate in the upper part of the elution tank 8, since the exhaust port 10 is provided in the upper part of the elution tank 8, the hydrogen gas in the elution tank 8 is efficiently discharged from the elution tank 8 together with air. The hydrogen gas concentration is prevented from rising due to the discharged hydrogen gas remaining in the elution tank 8.

In the embodiment of the present invention, when the electrode 12 made of an iron material is immersed in the treatment water in the elution tank 8 for a long time, an oxide film is generated on the electrode surface, and the electrode is in a passivated state, and The elution of ions gradually decreases, and the dephosphorization performance decreases.

Accordingly, it is preferable that a constant DC current is applied between a pair of electrodes made of an iron material, and the polarity of the current is changed every predetermined time. An oxide film is formed on the surface of the iron material on the anode side when used for a long period of time, but the surface of the iron material on the cathode side is cleaned by hydrogen gas generated from the iron material on the cathode side, and no oxide film is formed. Therefore, the elution of iron ions can be maintained substantially constant by changing the polarity at a time interval until an oxide film is formed on the iron material surface on the anode side and the elution of iron ions is reduced, and the phosphorus removal performance can be maintained. Can be kept constant.

In this configuration, since both electrodes are made of iron material, iron ions are always eluted from the iron material serving as the anode electrode and supplied to the treated water, so that the dephosphorization performance is always maintained at a constant state. can do.

It is also possible to adopt a structure in which an iron material is used at least on the anode side of the electrode, a DC constant current is applied between both electrodes, and the applied current is increased in a pulsed manner at predetermined time intervals. In this configuration, by increasing the applied current in a pulsed manner, the oxide film generated on the surface of the iron material on the anode side can be peeled off, and the elution of iron ions is kept almost constant, and the dephosphorization performance is kept constant. Can be maintained. Although the amount of hydrogen gas generated increases with an increase in the applied current, the amount of air supplied to the first blower 15 may be increased with an increase in the applied current.

Further, a configuration may be adopted in which a DC constant current is applied between a pair of electrodes made of an iron material, the polarity of the current is changed at predetermined time intervals, and the applied current is increased in a pulsed manner. If the time required for the polarity change is long, an oxide film is formed on the iron material surface on the anode side, and by changing the polarity, the oxide film can be washed and removed with a hydrogen gas. Some time is required until the oxide film is peeled off, and the electric resistance until the oxide film is peeled off is large, which may increase power consumption.

Therefore, the oxide film on the surface of the iron material, which has been converted from the anode to the cathode, can be removed in a short time by increasing the applied current in a pulsed manner as described above, and an increase in power consumption can be prevented.

In the embodiment of the present invention, an iron material is used for both electrodes as an electrode for applying a DC constant current to elute iron ions. However, an iron material is used for the anode electrode, and a titanium electrode is used for the cathode electrode. Alternatively, a configuration using an insoluble material such as platinum or platinum may be used.

In the embodiment of the present invention, an iron material is used for both electrodes as an electrode for applying a DC constant current to elute iron ions, but a structure using aluminum may be used.

[0067]

According to the structure of the first aspect of the present invention, hydrogen gas generated in the elution tank by electrolysis of the electrode can be diluted, thereby preventing explosion at the time of maintenance or the like and improving reliability. And the like.

According to the configuration of the second aspect of the present invention, hydrogen gas generated in the elution tank by electrolysis of the electrode can be diluted, explosion during maintenance or the like can be prevented, and reliability can be improved. And so on.

According to the configuration of claim 3 of the present invention, hydrogen gas generated in the elution tank by electrolysis of the electrode can be diluted by the blowing means, thereby preventing explosion at the time of maintenance or the like and improving reliability. It has effects such as being able to do.

According to the configuration of the fourth aspect of the present invention, there are the effects that the ion elution amount can be kept substantially constant.

According to the configuration of claim 5 of the present invention, both electrodes can be reduced substantially uniformly, and both electrodes can be replaced at the same time, so that effects such as easy maintenance can be obtained.

According to the configuration of claim 6 of the present invention, the oxide film generated on the surface of the iron material on the anode side can be peeled off, so that the ion elution amount can be prevented from decreasing and the power consumption can be reduced. To play.

According to the configuration of claim 7 of the present invention, the oxide film generated on the surface of the anode-side iron material can be peeled off, the ion elution amount can be prevented from lowering, and both electrodes can be reduced substantially uniformly. The electrodes can be exchanged at the same time, and effects such as easy maintenance can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a sewage treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view as viewed from another direction.

FIG. 3 is an enlarged sectional view of the elution device.

FIG. 4 is a perspective view of the same water measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing tank 5 1st anaerobic part (anaerobic part) 8 Elution tank 12 Electrode 14 1st air diffuser (air diffuser) 15 1st blower (blowing means) 22 aerobic part 28 sedimentation part 57 Control circuit (control means)

Claims (7)

[Claims] 1. A treatment tank having an anaerobic part, an aerobic part, and a sedimentation part, an elution tank for applying an electric current to an electrode made of iron material or aluminum to elute iron ions or aluminum ions, and a dissolution tank disposed in the elution tank. An air diffuser pipe for supplying air into the sewage in the elution tank, and a supply unit for supplying iron ions or aluminum ions eluted in the elution tank to the sewage in the treatment tank. A means for setting the amount of air supplied to the wastewater in the elution tank according to the total current value of the wastewater. 2. A treatment tank having an anaerobic part, an aerobic part, and a sedimentation part, an elution tank for applying an electric current to an electrode made of iron material or aluminum to elute iron ions or aluminum ions, and disposing in the elution tank. An air diffuser pipe for supplying air into the sewage in the elution tank, and a supply unit for supplying iron ions or aluminum ions eluted in the elution tank to the sewage in the treatment tank. A sewage treatment apparatus provided with control means for detecting a total current value of the wastewater and controlling an air supply amount to the sewage in the elution tank based on the detected total current value. 3. A treatment tank having an anaerobic part, an aerobic part, and a sedimentation part, an elution tank for applying an electric current to an electrode made of iron material or aluminum to elute iron ions or aluminum ions, and disposing in the elution tank. A diffuser pipe provided, a blower connected to the diffuser pipe and supplying air to the wastewater in the elution tank via the diffuser pipe, and an iron ion or aluminum ion eluted in the elution tank in the treatment tank. Supply means for supplying to the sewage, detecting a total current value applied to the electrode, and supplying air represented by the following formula A to the sewage in the elution tank based on the detected total current value. A sewage treatment apparatus comprising control means. (Equation 1) 4. The sewage treatment apparatus according to claim 1, wherein a DC constant current is applied to said electrode. 5. The sewage treatment apparatus according to claim 1, wherein a direct current for changing the polarity is applied to the electrode at predetermined time intervals. 6. The sewage treatment apparatus according to claim 1, wherein a direct current whose applied current increases in a pulsed manner at predetermined time intervals is applied to said electrode. 7. The sewage treatment apparatus according to claim 1, wherein a direct current is applied to the electrode, the polarity of which is changed every predetermined time and the applied current is increased in a pulsed manner.