JPH11179395A - Sewage treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewage treating device, having a simplified structure, for removing phosphorus. SOLUTION: An elution tank 19 which has a metal consisting of iron or aluminum and elutes an iron or aluminum ion, and a treating tank 1 which purifies sewage are made to communicate with each other through a supply passage 29 which supplies the sewage in the treating tank 1 to an elution tank 19 by air lift effect, and a return passage 24 which returns the sewage in the elution tank 19 to the treating tank 1, wherein the supply passage 29 communicating with the elution tank 19 is made to face the lower part of the metal.

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 A sewage treatment apparatus of this type is known, for example, from Japanese Patent Application Laid-Open No. 7-108296 (C02F3 / 30).

[0003] This apparatus comprises a treatment tank having an anaerobic section and an aerobic section for purifying sewage, an elution tank having an iron material and a diffuser pipe for aerating the iron material, and a treatment tank for treating sewage in the treatment tank through the elution tank. With a circulation pump that circulates through the tank, allowing the wastewater in the aerobic part to be returned to the anaerobic part via the elution tank by the circulation pump,
The reaction between iron ions eluted from the iron material and orthophosphoric acid in sewage causes aggregation and precipitation as a water-insoluble phosphorus compound to remove phosphorus from sewage.

However, when the iron material is immersed in the sewage for a long period of time, an oxide film is formed on the surface of the iron material and the iron material is in a passivated state, and the elution of iron ions is gradually reduced. In addition to the need for a trachea, a circulating pump is required to supply iron ions eluted from the elution tank to the sewage in the treatment tank in order to remove phosphorus from the sewage. is there.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a sewage treatment apparatus having a simplified configuration in a sewage treatment apparatus for removing phosphorus. .

[0006]

A first means for solving the above problems is a treatment tank having an anaerobic part, an aerobic part, a sedimentation part and a disinfecting part, and is located above the wastewater in the treatment tank. In addition, an elution tank having a metal made of iron or aluminum and eluted with iron ions or aluminum ions, a supply path communicating the wastewater in the treatment tank with the elution tank, and a supply path communicating with the wastewater in the treatment tank An aeration device for aerating the wastewater in the treatment tank and supplying the wastewater in the treatment tank to the elution tank via a supply path by an air lift effect, and a return path for returning the wastewater in the elution tank to the treatment tank; The supply path communicating with the metal faces the lower part of the metal.

[0007] A second means for solving the above problems is as follows.
A treatment tank having an anaerobic part, an aerobic part, a sedimentation part and a disinfection part,
An elution tank that is located above the wastewater in the treatment tank and has an electrode made of iron material or aluminum, and that supplies electricity to the electrode to elute iron ions or aluminum ions, and communicates the wastewater in the treatment tank with the elution tank; Supply path, an aeration device for aerating sewage in a supply path communicating with sewage in the treatment tank and supplying sewage in the treatment tank to the elution tank via the supply path by an airlift effect, and sewage in the elution tank. And a return path for returning to the anaerobic section, a supply path communicating with the elution tank facing the lower part of the electrode.

[0008] A third means for solving the above problems is as follows.
A treatment tank having an anaerobic part, an aerobic part, a sedimentation part and a disinfection part,
An elution tank that is located above the wastewater in the treatment tank and has an electrode made of iron material or aluminum, and that supplies electricity to the electrode to elute iron ions or aluminum ions, and communicates the wastewater in the treatment tank with the elution tank; A supply path, and an aeration device for aerating sewage in the supply path communicating with the sewage in the treatment tank and supplying the sewage in the treatment tank to the elution tank via the supply path by an airlift effect; and A return path for returning sewage to the anaerobic section, a flow control device for adjusting the flow rate of sewage discharged from the elution tank, and one end of a supply path communicating with the elution tank facing the lower part of the electrode. Features.

A fourth means for solving the above problems is as follows.
A treatment tank having an anaerobic part, an aerobic part, a sedimentation part and a disinfection part,
An elution tank that is located above the wastewater in the treatment tank and has an electrode made of iron material or aluminum, and that supplies electricity to the electrode to elute iron ions or aluminum ions, and communicates the wastewater in the treatment tank with the elution tank; Supply path, an aeration device for aerating sewage in a supply path communicating with sewage in the treatment tank and supplying sewage in the treatment tank to the elution tank via the supply path by an airlift effect, and sewage in the elution tank. A return path for returning the wastewater to the anaerobic section, and a supply path communicating with the elution tank facing the lower part of the electrode. It is characterized by the following.

[0010] In the first to fourth means for solving the above problems, it is preferable that the opening area of the supply passage communicating with the elution tank is made larger than the other end.

[0011]

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 composed of a first anaerobic part 5, a second anaerobic part 10, and a second anaerobic part 10, which will be described later, by a first partition 2, a second partition 3 and a third partition 4.
It is divided into an aerobic part 14, a sedimentation part 34 and a disinfection part 35.

Reference numeral 5 denotes a first anaerobic section having an inflow port 6 into which sewage such as domestic wastewater flows, and reference numeral 7 denotes a first anaerobic filter disposed in the first anaerobic section 5. The hardly decomposable contaminants mixed in the sewage that has flowed into
Anaerobic microorganisms attached to the anaerobic filter bed 7 anaerobically decompose organic substances and change organic nitrogen to ammonia nitrogen.

Reference numeral 8 denotes a first anaerobic section 5 provided in the first anaerobic section 5.
In the advection pipe, the wastewater anaerobically decomposed in the first anaerobic section 5 is
The water is supplied to a second anaerobic section 10 to be described later through a first water supply port 9 penetrating the upper portion of the first partition wall 2.

Reference numeral 10 denotes a first anaerobic section 5 formed by the first partition wall 2.
The second anaerobic section 11 is a second anaerobic filter bed provided in the second anaerobic section 10, wherein the second anaerobic filter bed 11 captures suspended matter and anaerobics organic substances by anaerobic microorganisms. Decomposes and converts organic nitrogen to ammonia nitrogen.

Reference numeral 12 denotes a second anaerobic section 10 provided in the second anaerobic section 10.
In the advection pipe, the sewage that has been anaerobically decomposed in the second anaerobic section 10 is
Water is supplied to an aerobic section 14 described later via a second water supply port 13 penetrating the upper part of the second partition wall 3. Reference numeral 14 denotes an aerobic section partitioned by the second partition wall 3 from the second anaerobic section 10, and sewage subjected to anaerobic treatment in the second anaerobic section 10 flows in through the second advection pipe 12. Fifteen
Is a contact material disposed in the aerobic part 14, which promotes the culture of aerobic microorganisms.

Reference numeral 16 denotes a first air diffuser disposed at the bottom of the aerobic section 14, which forms a number of air outlets and is connected to a first blower 17 to supply air supplied from the first blower 17. The air is discharged from the air outlet to maintain the inside of the aerobic section 14 in an aerobic state, aerobic decomposition of sewage by aerobic microorganisms, and nitric acid or nitrite to reduce ammoniacal nitrogen to nitric acid or nitrite. To nitrogen.

Reference numeral 18 denotes a second air diffuser disposed below the contact member 15 and having a large number of air outlets.
Is connected to Air is supplied from the first blower 17 to one of the first diffuser pipe 16 and the second pipe trachea 18 by a first solenoid valve (not shown).

The first solenoid valve normally discharges the air supplied from the first blower 17 from the air outlet of the first air diffuser 16 to maintain the inside of the aerobic section 14 in an aerobic state, and the contact material 15 When cleaning the, the control unit switches the first solenoid valve to the second air diffuser 18, and discharges air from the air outlet of the second air diffuser 18,
The biological film that has adhered to the contact material 15 and has grown and gradually thickened is peeled off.

Reference numeral 19 denotes a rectangular box-shaped elution tank disposed at a position above the third partition wall 4 and facing a third inspection opening 42 described later. It is partitioned into a first water diversion chamber 21 and a second water diversion chamber 22. 23 is the electrode installation room
By supplying a constant DC current from a power supply device (not shown) between the pair of electrodes 23, iron ions eluted from the electrodes 23 are supplied into the elution tank 19.

The first water diversion chamber 21 is provided between the bottom of the aerobic section 14 and the first
A first return pipe 24 that communicates with the upper part of the anaerobic section 5 is communicated via a pipe 25 with the first return pipe 24, and is communicated with the electrode disposition chamber 20 by a notch 26 having a V-shaped open upper part of the partition wall. The second water diversion chamber 22 communicates with the aerobic section 14 via a discharge port 27, and communicates with the electrode disposition chamber 20 through an opening formed in a height-adjustable overflow weir plate 28. I have.

The height of the overflow weir 28 is adjusted so that the overflow weir 28
The amount of sewage flowing into the first return pipe 24 from the first water diversion chamber 21 by changing the height of the opening formed in the first water diversion chamber 22 and setting the amount of sewage returned to the aerobic section 14 from the second water diversion chamber 22 Can be adjusted.

Reference numeral 29 denotes a second return pipe for communicating the electrode disposition chamber 20 of the elution tank 19 with a sedimentation section 34 described later. The opening area of one end of the second return pipe 29 which communicates with the electrode arrangement chamber 20 is tapered and is larger than the other end. Reference numeral 30 denotes a third air diffuser disposed at the bottom of the second return pipe 29, which forms a number of air outlets and is connected to the second blower 31;
By discharging the air supplied from the blower 31 from the air outlet, the sewage in the settling portion 34 is sucked into the second return pipe 29 and is transferred to the electrode installation chamber 20.

Reference numeral 32 denotes a fourth air diffuser disposed at the bottom of the first return pipe 24. The fourth air diffuser forms a number of air outlets and is connected to the second blower 31. The second blower
The air from 31 is supplied to the third diffuser by the second solenoid valve (not shown).
It is supplied to either one of 30 and the fourth diffuser 32.

The second solenoid valve normally switches to the third air diffuser 30 and discharges the air supplied from the second blower 31 from the air outlet of the third air diffuser 30 so that the supernatant in the sedimentation section 34 is removed. The liquid is sucked into the second return pipe 29, and the
To be transported to.

After the contact material 15 has been washed, the air supply from the second blower 31 is switched to the fourth air diffuser 32 and the air is discharged from the air outlet of the fourth air diffuser 32, whereby the aerobic part 14 is discharged. The sewage therein passes through the first return pipe 24 and flows into the first anaerobic section 5. The sludge deposited at the bottom of the aerobic section 14 along with this flow and the sludge returned from the sedimentation section 34 to the aerobic section 14 are returned to the first return pipe.
It is sucked into 24 and returned to the first anaerobic section 5.

A communication port 33 is provided at the bottom of the third partition wall 4 and communicates the aerobic section 14 with a sedimentation section 34 which will be described later. Reference numeral 34 denotes a sedimentation section which is separated from the aerobic section 14 by the third partition wall 4, and separates sewage which is aerobically decomposed in the aerobic section 14 and flows in from the communication port 33 into sludge and supernatant liquid. In addition, the sedimentation section
In order to return the sludge deposited on the bottom of the aerobic part 14 from the communication port 33, the bottom of the sedimentation part 34 is inclined toward the aerobic part 14.

Numeral 35 denotes a disinfecting part provided above the sedimentation part 34, and the supernatant liquid separated in the sedimentation part 34 flows therein. Reference numeral 36 denotes a sterilizing device provided in the disinfecting unit 35, which sterilizes sewage flowing into the disinfecting unit 35 by using a chlorine-based chemical or the like provided in the sterilizing device 36. A drain port 37 communicates with the disinfecting section 35, and drains sewage sterilized in the disinfecting section 35 to the outside of the treatment tank 1.

Reference numeral 38 denotes a first inspection opening provided at a position facing the first anaerobic section 5, and reference numeral 39 denotes a first lid body which closes the first inspection opening 38 so as to be openable and closable. 5 Open and close when sludge deposited on the bottom is removed by suction. Reference numeral 40 denotes a second inspection opening provided at a position facing the second anaerobic section 10 and the aerobic section 14 above the second partition wall 3.
Is a second lid that closes the second inspection opening 40 so that it can be opened and closed.

Reference numeral 42 denotes a third inspection opening provided at a position opposed to the sterilizing device 36 and the elution tank 19, and reference numeral 43 denotes a reed switch provided at the third inspection opening 42.
The open / closed state of the lid 44 is detected. Reference numeral 44 denotes a third lid body for closing the third inspection opening 42 so as to be able to close.
Is a magnet provided on the third lid 44 for turning on and off the reed switch 43. The third lid 44 is positioned such that the magnet 45 of the third lid 44 always faces the reed switch 43.
The lid 44 is positioned by positioning means (not shown).

The third lid 44 is opened and closed at the time of replenishing chlorine-based chemicals to the sterilizer 36 and maintenance of the elution tank 19 and the like. When the third inspection opening 42 is opened, the reed switch 43 is turned off, and based on this signal, the control circuit stops the supply of DC constant current to the electrode 23, and the third lid
When the electrode 44 is attached, the power supply to the electrode 23 is restarted.

The sewage discharged from the household flows into the first anaerobic section 5 through the inflow port 6 and the toilet in the sewage is filtered by the first anaerobic filter bed 7 provided in the first anaerobic section 5. Relatively coarse solids and contaminants such as paper are removed, and preliminary processing is performed to smoothly perform processing in each processing section that flows in later. The sewage passing through the filter bed 7 is anaerobically decomposed by the action of the anaerobic microorganisms, thereby reducing the BOD, and the sludge generated by the decomposition of the sewage accumulates at the bottom of the first anaerobic section 5. Organic nitrogen is changed to ammonia nitrogen by the action of anaerobic microorganisms.

The sewage which has been anaerobically decomposed by the inflow of new sewage into the first anaerobic section 5 is supplied to the first water supply port 9 of the first advection pipe 8
From the second anaerobic section 10. The sewage flowing into the second anaerobic section 10 is anaerobically decomposed by the action of anaerobic microorganisms in the second anaerobic filter bed 11 to reduce the BOD, and the sludge generated by the decomposition of the sewage is discharged to the bottom of the second anaerobic section 10. Deposited on Organic nitrogen is changed to ammonia nitrogen by the action of anaerobic microorganisms.

When new sewage flows into the second anaerobic section 10, sewage anaerobically decomposed in the second anaerobic filter bed 11 flows into the aerobic section 14 from the second water supply port 13 of the second advection pipe 12. The air supplied from the first blower 17 is discharged from the air outlet of the first air diffuser 16 to be stirred.

Then, oxygen is dissolved in the sewage and the contact material
The aerobic microorganisms attached to the surface of No. 15 decompose wastewater aerobically, decompose organic phosphates and the like into orthophosphoric acid, etc., and convert ammoniacal nitrogen into nitric or nitrite nitrogen. The sludge generated by the decomposition of the sewage accumulates at the bottom of the aerobic section 14.

When new sewage flows into the aerobic section 14, the sewage which has been aerobically decomposed by the action of the aerobic microorganisms attached to the contact material 15 passes through the communication port 33 at the bottom of the aerobic section 14 and the sedimentation section 34.
Flows into. The sewage flowing into the sedimentation section 34, the sedimentable substance settles while rising in the sedimentation section 34, and the aerobic part from the communication port 33.
The supernatant liquid is returned to 14, and flows into the disinfection unit 35. Disinfection department
The supernatant liquid that has flowed into 35 is sterilized by a sterilizing device 36 provided with a chlorine-based chemical or the like, kills bacteria such as pathogenic bacteria, and is drained out of the treatment tank 1 through a drain port 37.

The air supplied from the second blower 31 is supplied to a third blower.
By discharging from the air outlet of the air diffuser 30, the sedimentation section
The sewage in 34 flows into the electrode installation chamber 20, and iron ions eluted from the electrode 23 are supplied.

Further, since the distance between the third air diffuser 30 and the sewage surface is large, sufficient acceleration can be obtained before the air released from the third air diffuser 30 reaches the sewage surface.
The flow rate of the sewage flowing into the electrode disposition chamber 20 due to the air lift effect of the third diffuser 30 is increased, and the opening area of one end of the second return pipe 29 communicating with the electrode disposition chamber 20 of the elution tank 19 is changed. It is made larger in a tapered shape from the end, and the sewage flowing into the electrode disposition chamber 20 spreads over the entire circumference to form a flow path flowing to all the electrodes 23 surfaces, so that sludge and the like adhere to the surfaces of the electrodes 23. It can be prevented reliably.

Further, divalent iron ions eluted from the electrode 23 can be oxidized to trivalent iron ions reacting with orthophosphoric acid, using oxygen in the air supplied from the third air diffuser 30. The dephosphorization efficiency can be further improved.

The sewage supplied with trivalent iron ions in the electrode installation chamber 20 flows into the first water separation chamber 21 and the second water separation chamber 22.
By changing the height of the opening of the overflow weir plate 28 that connects the second water diversion chamber 22 and the electrode disposition chamber 20, the water is returned from the second water diversion chamber 22 to the aerobic part 14 through the discharge port 27. Since the amount of sewage to be discharged is determined, the amount of sewage flowing into the first return pipe 24 from the first water separation chamber 21 can be adjusted to a predetermined amount.

The iron ions in the sewage returned from the second water separation chamber 22 to the aerobic section 14 react with orthophosphoric acid present in the aerobic section 14 and aggregate and precipitate as a water-insoluble phosphorus compound. In addition, the first water separation chamber 21 is connected to the first return pipe 24 via the first return pipe 24.
The iron ions in the sewage returned to the anaerobic section 5 react with orthophosphoric acid present in the first anaerobic section 5, aggregate and precipitate as a water-insoluble phosphorus compound, and are returned to the first anaerobic section 5. The nitrate or nitrite nitrogen in the sewage is reduced by the denitrifying bacteria present in the first anaerobic section 5 in a large amount and is diffused into the air as nitrogen gas to be removed.

The sewage returned from the elution tank 19 to the first anaerobic section 5 is supplied not from the aerobic section 14 where the dissolved oxygen concentration is extremely high but from the sedimentation section 34. The cleaning of the electrode 23 and the oxidation of the eluted iron ions are performed by using the air supply from the third air diffuser 30 which is a return means for returning to the first anaerobic section 5 via 19. Since the amount of sewage returned to the first anaerobic section 5 is regulated to a predetermined amount by the first water dividing chamber 21 and the second water dividing chamber 22, anaerobic decomposition can be performed with little influence on anaerobic microorganisms.

The elution tank 19 is disposed so as to face the third inspection opening 42. The third lid 44 is opened and the disinfection device 36 of the disinfection tank 35 is opened.
The elution tank 19 can be inspected when replenishing chemicals to the apparatus.

Further, since the electrode disposition chamber 20 and the first water separation chamber 21 and the second water separation chamber 22 which constitute the flow rate control device are disposed in the elution tank 19, the third inspection opening 42 is provided. Open and elute tank 19
When maintenance is performed, the exhausted electrode 23 can be replaced, and the amount of sewage returned to the first anaerobic section 5 that has changed due to sludge or the like attached to the opening of the overflow weir plate 28 can be overflown. The sludge attached to the opening of the weir plate 28 can be easily returned to the original state by cleaning.

When the third inspection opening 42 is open, the electrode
Since the supply of the DC constant current to 23 is stopped, it is possible to prevent an electric shock at the time of replenishing chemicals to the sterilizing device 36, maintenance of the elution tank 19, and the like.

Since the biofilm formed by the aerobic microorganisms attached to the contact material 15 grows and gradually becomes thicker, the control unit periodically controls the first solenoid valve to prevent clogging so as to prevent the first blower. The air supply from 17 is switched to the second air diffuser 18, and air is released from the air outlet of the second air diffuser 18 to peel off the biofilm.

When the supply of air from the second air diffuser 18 is completed, the separated biofilm is deposited as sludge on the bottom of the aerobic part 14, but the control unit controls the second solenoid valve to control the second blower 31.
Is switched to the fourth air diffuser 32, and the fourth air diffuser
By discharging air from the 32 air outlets,
The sewage in 14 along with the sludge deposited at the bottom of the aerobic section 14
It is returned to the first anaerobic section 5 via the return pipe 24.

When the electrode 23 made of an iron material is immersed in the sewage in the elution tank 19 for a long time, an oxide film is generated on the surface of the electrode 23, and the electrode 23 is in a passivated state, and the elution amount of iron ions gradually increases. And the dephosphorization performance decreases.

Therefore, it is preferable that a DC constant current is supplied 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, by changing the polarity at a time interval until an oxide film is generated on the surface of the iron material on the anode side and the amount of elution of iron ions decreases, elution of iron ions can be maintained substantially constant, and phosphorus desorption can be maintained. Performance 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 side electrode and supplied to the wastewater, so that the dephosphorization performance is always maintained at a constant state. be able to.

In the above configuration, in this embodiment, 1
DC constant current of ~ 1.2A is supplied. The time interval for the polarity change of the current may be about 4 minutes or more at which the actual elution amount with respect to the theoretical iron ion elution is about 90% or more, and within 2 months when an oxide film is generated on the iron material surface. Within one week, to improve the durability of the switching element that converts the power, and to prevent only the iron material serving as the anode-side electrode from being reduced due to elution of iron ions to make both electrodes substantially uniformly reduced, Preferably, the polarity is changed within one day, and in this embodiment, every four hours.

It is also possible to adopt a configuration in which an iron material is used at least on the anode side of the electrode, a direct current is supplied to both electrodes, and the supply current is increased in a pulsed manner at predetermined time intervals. In this configuration, by increasing the supply current in a pulsed manner, the oxide film generated on the surface of the anode-side iron material can be peeled off, and the elution of iron ions is kept almost constant, and the dephosphorization performance is kept constant. Can be maintained.

In the above configuration, in the present embodiment, 1
Supply DC constant current of ~ 1.2A, total 2 per 4 hours
A pulse current of 3 to 4 A is supplied for 4 minutes.

Further, by combining the above two types of supply current configurations, a DC constant current is supplied between a pair of electrodes made of iron material, and the polarity of the current is changed at predetermined time intervals.
The supply current may be 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 is large until the oxide film is peeled off, so that power consumption may increase.

Therefore, by increasing the supply current in a pulsed manner as described above, the oxide film on the surface of the iron material converted from the anode to the cathode can be removed in a short time, 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 supplying 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.

Further, in the embodiment of the present invention, an iron material is used for both electrodes as an electrode for supplying a DC constant current and eluting iron ions, but a structure using aluminum for both electrodes may be used.

In the embodiment of the present invention, a configuration is adopted in which a DC constant current is supplied to an electrode made of an iron material to elute iron ions, but a metal made of iron or aluminum is provided in an elution tank 19. Alternatively, the metal surface may be washed with air released from the third diffuser 30 to elute iron ions or aluminum ions.

[0059]

According to the structure of the first aspect of the present invention, metal pieces can be efficiently cleaned by using an aeration device that circulates wastewater in a processing tank to a processing tank via an elution tank by an air lift effect. This has the advantage that the configuration can be simplified.

According to the configuration of the second aspect of the present invention, the electrodes can be efficiently cleaned by using the aeration device that circulates the wastewater in the treatment tank to the anaerobic section through the elution tank by the air lift effect. In addition to simplification, it is possible to return sewage in the treatment tank to the anaerobic section and to remove nitrogen from the sewage.

According to the structure of the third aspect of the present invention, the electrodes can be efficiently cleaned by using the aeration device that circulates the wastewater in the treatment tank to the anaerobic part via the elution tank by the air lift effect. While being able to simplify, a predetermined amount of wastewater in the treatment tank can be returned to the anaerobic section,
It has the effect that nitrogen can be efficiently removed from sewage.

According to the structure of the fourth aspect of the present invention, the electrodes can be efficiently cleaned by using the aeration device that circulates the wastewater in the treatment tank to the anaerobic part through the elution tank by the air lift effect. While being able to simplify, a predetermined amount of wastewater in the treatment tank can be returned to the anaerobic section,
Nitrogen can be efficiently removed from wastewater.

Further, since the flow rate adjusting device is provided in the elution tank, the replacement of the electrode and the cleaning of the flow rate adjusting device can be performed at the same time.

According to the structure of the fifth aspect of the present invention, the opening area of the supply passage communicating with the elution tank is made larger than the other end, and the wastewater supplied to the elution tank is stirred over a wide area in the elution tank. Therefore, even when a plurality of electrodes are provided, it is possible to prevent sludge and the like from adhering to all the electrodes, and to improve the ion elution efficiency and improve the phosphorus removal efficiency. Play.

[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 sectional view of the same.

FIG. 3 is a perspective view of the elution tank.

[Explanation of symbols]

 1 Treatment tank 5 1st anaerobic section (anaerobic section) 10 2nd anaerobic section (anaerobic section) 14 aerobic section 19 elution tank 23 electrode 29 2nd supply pipe (supply path) 30 3rd diffuser pipe (aeration device) 34 sedimentation Part 36 Disinfection part 42 Third inspection opening 43 Reed switch 44 Third lid 45 Magnet

Claims (5)

[Claims] 1. A treatment tank having an anaerobic part, an aerobic part, a sedimentation part and a disinfecting part, and an iron ion or an aluminum ion which is located above sewage in the treatment tank and has a metal made of iron or aluminum. An elution tank to elute, a supply path communicating the wastewater in the treatment tank with the elution tank, and a supply path for aerating the wastewater in the supply path communicating with the wastewater in the treatment tank by airlift effect. And an aeration device for supplying to the elution tank via a recirculation tank, and a return path for returning the wastewater in the elution tank to the treatment tank, wherein a supply path communicating with the elution tank faces the metal lower part. Sewage treatment equipment. 2. A treatment tank having an anaerobic part, an aerobic part, a sedimentation part, and a disinfection part, and an electrode made of iron material or aluminum, which is located above sewage in the treatment tank, An elution tank that elutes iron ions or aluminum ions, a supply path that communicates the wastewater in the treatment tank with the elution tank, and a wastewater in the treatment tank that aerates the wastewater in the supply path that communicates with the wastewater in the treatment tank. An aeration device for supplying air to the elution tank via a supply path by an air lift effect, and a return path for returning the sewage in the elution tank to the anaerobic section, wherein a supply path communicating with the elution tank was facing the lower part of the electrode. A sewage treatment apparatus characterized by the above-mentioned. 3. A treatment tank having an anaerobic part, an aerobic part, a sedimentation part, and a disinfecting part, and an electrode made of iron material or aluminum, which is located above the wastewater in the treatment tank, and which is energized. An elution tank that elutes iron ions or aluminum ions, a supply path that communicates the wastewater in the treatment tank with the elution tank, and a wastewater in the treatment tank that aerates the wastewater in the supply path that communicates with the wastewater in the treatment tank. Aeration device for supplying air to the elution tank via a supply path by an air lift effect, and a return path for returning the wastewater in the elution tank to the anaerobic section, and a flow rate control for adjusting the flow rate of the wastewater discharged from the elution tank. A sewage treatment apparatus comprising an apparatus and a supply path communicating with the elution tank facing a lower part of the electrode. 4. A treatment tank having an anaerobic part, an aerobic part, a sedimentation part, and a disinfecting part, and an electrode made of iron or aluminum, which is located above the wastewater in the treatment tank, and which is energized. An elution tank that elutes iron ions or aluminum ions, a supply path that communicates the wastewater in the treatment tank with the elution tank, and a wastewater in the treatment tank that aerates the wastewater in the supply path that communicates with the wastewater in the treatment tank. An aeration device for supplying the elution tank via a supply path by an air lift effect, and a return path for returning the sewage in the elution tank to the anaerobic section, one end of the supply path communicating with the elution tank is provided below the electrode. A sewage treatment apparatus characterized in that a flow control device for controlling the flow rate of sewage discharged from the elution tank is provided in the elution tank. 5. The sewage treatment apparatus according to claim 1, wherein an opening area of a supply passage communicating with the elution tank is made larger than that of the other end.