KR100303234B1 - Sewage disposal appratus - Google Patents

Abstract

Provided is a sewage treatment apparatus capable of simultaneously removing phosphoric acid and nitrogen.

The sewage treatment apparatus D ₁ includes a sewage storage tank 1, electrodes 2, 3, a DC power supply 11, and a control unit.

The electrodes 2 and 3 are rectangular iron plates, and the iron ions which remove phosphoric acid in the sewage are eluted by electrolysis.

The lower half of the electrodes 2 and 3 is covered with the carriers 9 and 10 which are made of a porous network made of polypropylene resin.

The carriers 9 and 10 reproduce microorganisms involved in the denitrogenation reaction in sewage.

When the control unit reverses the polarity of the electrodes 2 and 3, the phosphoric acid is removed by the coagulation reaction between the iron ions and the phosphate ions in the sewage on the electrodes 2 and 3 with the polarity as the anode. do.

In addition, nitrogen is removed by denitrification based on microorganisms in the carriers 9 and 10 on the electrodes 2 and 3 having the polarity as the negative electrode.

Description

Sewage Treatment Equipment {SEWAGE DISPOSAL APPRATUS}

The present invention relates to a sewage treatment apparatus, and more particularly, to a sewage treatment apparatus for reacting phosphoric acid contained in sewage, such as manure wastewater and domestic wastewater, with metal ions eluted by electrolysis to precipitate out. .

As the sewage treatment apparatus of this kind, the following are known conventionally.

That is, a sewage storage tank for storing sewage to be treated is provided, and at least one electrode of water-insoluble phosphate-forming metal is disposed in the storage tank, and a current is supplied to these electrodes to supply water-insoluble phosphate-forming metal ions. It is a device that electrochemically elutes in sewage, and makes phosphoric acid water insoluble salt to precipitate out.

In such a sewage treatment apparatus, although water-insoluble phosphate-forming metal ions eluted from the electrode can be coagulated by phosphate ions in the sewage, phosphoric acid can be removed, but nitrogen in the sewage cannot be removed.

This invention is made | formed in view of such a situation, Comprising: It is a subject to provide the sewage treatment apparatus which can perform both the removal of phosphoric acid and the removal of nitrogen.

BRIEF DESCRIPTION OF THE DRAWINGS The explanatory drawing of the structure which looked at the inside of the sewage treatment apparatus of Embodiment 1 of this invention from the side surface.

2 is an explanatory view of the configuration of the sewage treatment apparatus of FIG.

3 is a perspective view of an electrode and a carrier which are members of the sewage treatment apparatus of FIG. 1;

4 is an enlarged configuration explanatory view of the inside of a merge treatment septic tank in which the sewage treatment apparatus of FIG. 1 is assembled;

5 is an exploded perspective view of the sewage treatment apparatus of Embodiment 2 of the present invention.

6 is a perspective view of an electrode and an electrode case which are constituent members of the sewage treatment apparatus of FIG.

FIG. 7 is an enlarged configuration explanatory view of the inside of a merge treatment septic tank in which the sewage treatment apparatus of FIG. 5 is assembled;

(Explanation of symbols on the main parts of drawing

One ; Sewage storage tank

2 ; electrode

3; electrode

4 ; An introduction tube

9; Carrier

10; carrier

11; power

12; A wide pipe

13; A bomber

14; An air blower

15; Air supply switching valve

16; Air supply

17; Air supply

18; Partition plate

19; Flow path switching valve

31; Sewage storage tank

32; Electrode case

According to the present invention, at least one electrode is disposed so as to be immersed in at least one of the sewage storage tank and the sewage stored in the sewage storage tank, and at least one electrode which elutes iron or aluminum ions by electrolysis to precipitate and remove phosphoric acid in the sewage. And a power supply for supplying an electrolytic current to these electrodes, and a control unit for controlling the power supply, wherein at least a part of each electrode is covered with a carrier for reproducing microorganisms involved in the denitrification reaction in sewage, The control unit periodically reverses the polarity of the electrode, and the phosphoric acid is removed from the electrode side of which the polarity is positive, and nitrogen from the denitrification reaction based on the microorganisms in the carrier is of the electrode side of the polarity of the negative electrode. Sewage treatment apparatus is provided, characterized in that the removal of.

The sewage treatment tank accommodates the sewage provided for the electrolytic treatment.

For example, at least one set of rectangular plate-shaped objects is disposed, and the iron ions or aluminum ions are eluted to the sewage treatment tank by electrolysis.

The power supply supplies current for electrolysis to these electrodes.

The controller controls the electrolysis by controlling the power supply.

A set of electrodes is, for example, both constructed from one of iron and aluminum, or one from iron and aluminum, and the other from a water insoluble metal.

In the case of the former, the polarity inversion of the electrode can be performed as desired, thereby preventing passivation of the electrode from which ion elution from the electrode does not occur.

In the latter case, the electrode composed of one of iron and aluminum is used as the anode, and the electrode composed of water insoluble metal is used as the cathode.

Here, as an electrode comprised from a water insoluble metal, there exist electrodes, such as silver and platinum, for example.

Moreover, it is good that a set of electrodes hold | maintains the space | interval constant, for example by the electrically insulating spacer with a handle part.

Iron or aluminum ions eluted in the sewage treatment tank react with phosphoric acid (orthophosphoric acid) in sewage, resulting in water insoluble phosphorus compounds (Fe (OH) _x (PO ₄ ) _y or A1 (OH) _x (PO ₄ ) _y ) And coagulate and settle in the sewage treatment tank.

Each electrode is covered with a carrier at least part of it (the part to be immersed in sewage).

This carrier is intended to reproduce microorganisms (for example, denitrification bacteria, which are a kind of anaerobic microorganisms) involved in the denitrification reaction in sewage.

The material of the carrier is not particularly limited as long as it can reproduce microorganisms involved in the denitrification reaction in sewage.

For example, a porous network of plastic, carbon fiber or sintered ceramic is used.

The carrier is, for example, attached at the upper edge of each electrode or placed on the bottom of an electrode case for accommodating a set of electrodes, and disposed so as to cover at least a part of each electrode.

The controller periodically reverses the polarity of the electrode at a rate of once every 30 minutes to 10 days (more preferably, 1 hour to 7 days, more preferably 2 days to 7 days).

In this case, the phosphoric acid is removed by the aggregation reaction between iron ions or aluminum ions and phosphate ions in the filthy water on the electrode side having a positive polarity.

Further, nitrogen is removed by a denitrification reaction (reaction of nitrate ions or nitrite ions in the wastewater reduced to nitrogen gas) based on the microorganisms in the carrier on the electrode side having the polarity of the negative electrode.

The sewage treatment apparatus according to the present invention preferably comprises a partition plate for partitioning a set of electrodes from the anode side and the cathode side, and an aeration device for aeration of each electrode. In addition, the aeration device is controlled so that the aeration is applied only to the electrode having a positive polarity.

In such a configuration, the aeration device is used to aeration only to the electrode on the anode side to promote the removal reaction of phosphoric acid on the anode side and to wash the electrode, while the electrode on the cathode side is in a reducing atmosphere. You can leave

As the partition plate, for example, ceramics or ion exchange membranes are used to move only ions through the partition plate, or plastics which do not allow ions to pass through to move the ions through the bottom of the partition plate, etc. This is used.

In addition, the aeration device includes, for example, an air supply blower installed outside the sewage storage tank, a supply pipe connected to the blower and extending into the storage tank, and an aeration pipe connected to the air supply pipe and disposed at the bottom of the storage tank. Equipped.

The sewage treatment apparatus of the present invention preferably further includes an introduction pipe for introducing sewage into the sewage storage tank, and the partition plate in the sewage storage tank is configured to pass the sewage from the introduction pipe into the sewage storage tank via one end of the partition plate. Inflow to guide the other end along one side or the other side of the partition plate, and then turn the other end to flow out through one end along the other side or one side, between the introduction pipe and the sewage tank, A flow path switching valve is also provided for switching the waste water from the inlet pipe to be guided along one of the side and the other side of the partition plate, and the control unit controls the flow path switching valve again to polarize the waste water from the inlet pipe. It is comprised so that it may flow in into the side of the partition plate with the electrode of this cathode first.

In such a case, the control unit controls the flow path switching valve to first introduce the sewage from the inlet pipe to the side surface of the partition plate with the electrode having the negative polarity.

Then, the introduced sewage then turns to the side of the partition plate with the anode electrode by turning the other end of the partition plate.

Therefore, after sufficiently performing the denitrification reaction on the cathode side where the dissolved oxygen concentration is relatively low, the agglomeration reaction and washing can be performed on the anode side where the dissolved oxygen concentration is increased by aeration.

(Example)

EMBODIMENT OF THE INVENTION Hereinafter, two embodiment of this invention is described based on drawing.

In addition, this invention is not limited by these embodiment.

(Embodiment 1)

As Figure 1 and shown in Figure 2, the sewage treatment device (D ₁₎ of the first embodiment of the present invention, supplying current to a waste water storage tank (1), two pairs of electrodes 2 and 3 DC power supply 11 for control, and the control part (not shown) for controlling this power supply 11 are provided.

The sewage storage tank 1 is made of a box having a tapered bottom wall having a substantially rectangular planar shape and containing sewage to be treated, such as manure wastewater or domestic wastewater.

In the upper part of one end wall of the wastewater storage tank 1, the wastewater inflow port 1a connected to the inlet pipe 4 for introducing wastewater into the wastewater storage tank 1 is formed.

As shown in FIG. 3, the electrodes 2 and 3 of each group become a rectangular iron plate, and elutes iron ions for removing phosphoric acid in sewage by electrolysis.

Moreover, the space | interval of each set of electrodes 2 and 3 is kept constant by the electrically-insulating spacer 5 made of vinyl chloride resin provided in these upper ends, and the handle part 5a is provided in the spacer 5. ) Is formed.

The terminal 6 for a connection is provided in the upper end of the electrode 2,3.

These terminals 6 are connected to the connector 8 via the lead wire 7.

The lower half of the electrodes 2, 3 is covered with the carriers 9, 10 made of a porous network made of polypropylene resin.

These carriers 9 and 10 are attached to the upper edges of the electrodes 2 and 3 by strings (not shown) and reproduce microorganisms involved in the denitrogenation reaction in filthy water.

As shown to FIG. 1 and FIG. 2, under the two sets of electrodes 2 and 3, two width pipes 12 and 13 are horizontally arrange | positioned in parallel with these.

The width of pipe (12, 13) is a part of the aerator comprising a sewage treatment unit (D _1).

That is, this aeration apparatus is connected to the air supply fan 14 provided in the exterior of the sewage storage tank 1, and two air supply pipes connected to this blower 14 through the air supply switching valve 15, and extend into a storage tank. (16) and (17) and width pipes (12) and (13) connected to these air supply pipes (16) and (17) and disposed at the bottom of the storage tank.

The control unit is configured to invert the polarity of the electrodes 2 and 3 here at a rate of once every 5 days.

When the control unit reverses the polarity of the electrodes 2 and 3, the phosphoric acid is removed by the coagulation reaction between the iron ions and the phosphate ions in the sewage on the electrodes 2 and 3 with the polarity as the anode. do.

In addition, denitrification reaction based on microorganisms in the carriers 9 and 10 on the electrodes 2 and 3 having the polarity of the cathode (reduction of nitrate ions and nitrite ions in filthy water to nitrogen gas) Reaction) is carried out.

The sewage treatment apparatus D ₁ further includes a rectangular partition plate 18 for partitioning the pair of electrodes 2 and 3 to the anode side and the cathode side.

The partition plate 18 is made of a ceramic so that only ions are moved through the partition plate 18.

The partition plate 18 flows the sewage from the inlet pipe 4 into the sewage storage tank 1 via one end of the partition plate 18 (the end of the introduction pipe 4 side), and the partition plate ( 18) is arranged to lead to the other end along one side or the other side, and then turn the other end to flow out through one end along the other side or one side.

In addition, a flow path switching valve 19 is provided between the introduction pipe 4 and the sewage storage tank 1.

The flow path switching valve 19 is switched by the control unit so that the wastewater from the inlet pipe 4 is guided along either one side or the other side of the partition plate 18.

The control unit is also configured to control the flow path switching valve 19 to first introduce the sewage from the inlet pipe 4 to the side of the partition plate 18 having the electrodes 2 and 3 having the polarity as the negative electrode. It is.

Since it is comprised in this way, as shown in FIG. 2, the polarity of the electrodes 3 and 3 in one side of the partition plate 18 is controlled to become a cathode, and the flow path switching valve 19 is controlled, The filthy water from the inlet pipe (4) passes through the inflow path (19a) of the flow path switching valve (19) toward the side of the partition plate (18) with the electrodes (3) and (3) of the polarity as the arrow. Inflow first.

Then, the introduced sewage is then turned to the other side of the partition plate 18 (side with the anode electrodes 2 and 2) by turning the other end of the partition plate 18 and switching the flow path as shown by the arrow. It flows out from the sewage storage tank 1 via the outflow path 19b of the other side of the valve 19. As shown in FIG.

Therefore, after the denitrification reaction is sufficiently performed on the cathode side where the dissolved oxygen concentration is relatively low, the agglomeration reaction can be performed on the anode electrodes 2 and 2 whose dissolved oxygen concentrations are increased by aeration.

In addition, the wastewater which flowed out from the outflow path 19b flows into the 1st anaerobic tank 104 mentioned later.

After that, when the polarity is inverted by the control unit, the flow path switching valve 19 is switched in conjunction with this, and the wastewater from the inlet pipe 4 has the polarities of the electrodes 2 and 2 having the negative polarity. It flows in through the inflow path 19a toward the other side of the partition plate 18 which exists.

The introduced sewage then turns to the other side of the partition plate 18 (side with the anode electrodes 3 and 3), turning to the other end of the partition plate 18, and to one side of the flow path switching valve 19. It flows out from the sewage storage tank 1 via the outflow path 19c.

1, 20 is a sludge draw valve.

The sludge accumulated in the sewage storage tank 1 is taken out by opening the sludge withdrawal valve 20.

Opening and closing of the sludge draw-out valve 20 is operated by a control part or manually.

As shown in FIG. 4, the sewage treatment apparatus D ₁ is assembled to the small combined treatment septic tank 101.

The inside of the septic tank 101 is a sewage purification process from the inflow pipe 102 side through which the sewage mixed with the wastewater and the domestic waste water flows into the discharge pipe 103 for discharging the sewage treatment to the outside. According to the process sequence of, a plurality of cylinders are partitioned.

104 is a 1st anaerobic filtration tank formed in the foremost part of the inflow pipe 102 side.

In the first anaerobic filtration tank 104, the sediment which is mixed in the manure wastewater or domestic wastewater and cannot be purified can be precipitated and removed.

The anaerobic filtration tank 105 which is a filtration phase of anaerobic microorganisms is installed in the 1st anaerobic filtration tank 104, and it makes it anaerobic-treatment by incubating microorganisms in the anaerobic filtration phase 105. As shown in FIG.

The anaerobic filtration 105 prevents the sediment from being rolled up by the flow of water when the inflow or backwash wastewater flows in temporarily and becomes suspended solids and outflows into the next reservoir, thereby reducing the load on the next reservoir. I can let you.

106 is the next second anaerobic filtration tank formed in a section adjacent to the first anaerobic filtration tank 104.

In the second anaerobic filtration tank 106, the anaerobic microorganism is incubated in the anaerobic filtration tank 107 to perform anaerobic treatment.

108 is a next biomembrane filtration tank partitioned adjacent to the second anaerobic filtration tank 106.

The first anaerobic filtration tank 104 and the second anaerobic filtration tank 106 are partitioned by a vertical separation wall 109.

On the upper part of the isolation wall 109, an airflow port 110 penetrating through the isolation wall 109 is formed.

And the airflow pipe 111 is fitted in the said airflow port 110. As shown in FIG.

The airflow pipe 111 has a lower end located under the anaerobic filtration bed 105 of the first anaerobic filtration tank 104 and serves as a cleaning tool.

The second anaerobic filtration tank 106 and the next biofilm filtration tank 108 are partitioned by a vertical separation wall 112.

On the upper part of the said isolation | separation wall 112, the airflow port 113 which penetrates the isolation | separation wall 112 is formed in opening.

And the airflow pipe 114 is fitted in the said airflow port 113.

The sewage which has flowed from the first anaerobic filtration tank 104 to the second anaerobic filtration tank 106 through the aeration pipe 111 passes the anaerobic filtration bed 107 in a descending flow, and then the aeration pipe 114. Is then sent to the next biofilm filtration tank 108.

A certain amount of SS is captured by the anaerobic filtration phase 107 installed in the second anaerobic filtration tank 106.

The trapped SS is gradually anaerobic and becomes soluble, or stored as sludge at the bottom of the second anaerobic filtration tank 106.

In the anaerobic filtration phase 107, organic nitrogen is anaerobicly decomposed into ammonia nitrogen.

The biofilm filtration tank 108 is provided with an aerobic filtration phase 115 that is a filtration phase of an aerobic microorganism. The aerobic treatment is performed by incubating the aerobic microorganism on the aerobic filtration phase 115.

In the vicinity of the bottom of the biofilm filtration tank 108, the aeration pipe 116 of the aeration device is disposed in a state where it is provided horizontally.

The aeration device blows air from the aeration pipe 116 to supply oxygen to the aerobic microorganisms that inhabit the aerobic filtration bed 115 of the biofilm filtration tank 108.

117 is the next treatment tank partitioned adjacent to the biofilm filtration tank 108.

In the treated water tank 117, the treated water that has been aerobic treated in the biofilm filtration tank 108, filtered, and flowed back to the stationary state is stored.

118 is a disinfection tank formed at the upper portion of the treatment water tank 117.

The disinfection tank 118 disinfects the clear upper layer water after the treatment in the treatment water tank 117, and discharges it from the discharge pipe 103 to the outside.

Between the biofilm filtration tank 108 and the subsequent treatment tank 117 is partitioned by a vertical separation wall 119.

On the upper part of the isolation wall 119, the airflow port 120 which penetrates the isolation wall 119 is formed in opening.

And the airflow pipe 121 is fitted in the airflow port 120.

The sewage which has flowed from the second anaerobic filtration tank 106 through the convection pipe 114 and has flowed into the biofilm filtration tank 108 passes through the aerobic filter bed 115 in a downward flow, and then passes through the convection pipe 121. To the next treatment tank (117).

The conveyance pipe 122 for conveying the clear upper layer water in a process water is arrange | positioned from the upper part of the process water tank 117 to the upper part of the 1st anaerobic filtration tank 101.

Feed pipe 122 is connected to the inlet tube (4) of the sewage treatment unit (D _1).

Then, the clear upper layer water pumped up by the lift pipe 123 from the treated water tank 117 is sent to the sewage treatment apparatus D ₁ via the conveying pipe 122 to remove phosphorus and nitrogen, and then, It is returned to the one anaerobic filtration tank 104.

(Embodiment 2)

5, the waste water treatment apparatus of Embodiment 2 of the present invention (D _2), the direct current for supplying an electric current to a waste water storage tank 31, four sets of electrodes 2 and 3 A power source 11, a control unit (not shown) for controlling the power source 11, and four electrode cases 32 are provided.

The lower half of the electrodes 2, 3 is covered with the carriers 9, 10 made of a porous network made of polypropylene resin, as in the sewage treatment apparatus D ₁ .

These carriers 9 and 10 are mounted on the bottom surface of the electrode case 32 unlike the sewage treatment apparatus D ₁ .

The sewage storage tank 31 is a box having a tapered bottom wall having a substantially rectangular planar shape, and containing sewage to be treated, such as manure wastewater and domestic wastewater.

The sewage inlet 31a and the sewage discharge port 31b are formed in the upper part of one side wall of the sewage storage tank 31.

At the bottom of the sewage storage tank 31, two bottom positioning bars 35 extending in the left and right directions are provided.

On the inner side of these bottom positioning bars 35, a total of six left and right positioning bars 36 extending in the longitudinal direction are provided.

As shown in FIG. 6, the electrode case 32 is a rectangular box shape of planar shape, and is made of polypropylene resin.

The left and right side walls of the electrode case 32 serve as an electrically insulating partition plate 32a for partitioning adjacent electrode cases 32 from each other.

The front and rear ends of the electrode case 32 are formed as a rectangular sewage inlet 32b and a sewage outlet 32c.

In addition, the upper and lower surfaces of the electrode case 32 are cut out in a rectangle, leaving the periphery edges, and are formed as an electrode detachable opening 32d and a width mechanism 32e, respectively.

The left and right widths of the electrode case 32 (the spacing between the outer surfaces of the two partition plates 32a) are approximately equal to the spacing between two adjacent left and right positioning rods 36 in the sewage storage tank 31. I am doing it equally.

The two circular holes 32f in the upper surface of the electrode case 32 are for screwing the spacer 5 to the upper surface of the electrode case 32.

The electrode case 32 comprised in this way is arrange | positioned so that it may be taken out in the waste water storage tank 31. As shown in FIG.

In other words, the bottom positioning bar 35 and the left and right positioning bars 36 provided in the storage tank are loosely fixed in the fixed positions.

In FIG. 5, 37 is a sludge withdrawal valve, and sludge accumulated in the sewage storage tank 1 opens and draws out the sludge withdrawal valve 37.

The configuration of the other portions (the controller) of the sewage treatment unit (D ₂₎ is the same as it is substantially a waste water treatment unit (D ₁₎ a detailed description thereof will be omitted.

As shown in FIG. 7, the sewage treatment apparatus D ₂ is assembled to the same small combined treatment septic tank 101 as described above.

Transporting pipe 122, also waste water of the sewage treatment apparatus (D ₂₎ is connected to the inlet (31a).

Then, the clear supernatant water pumped up by the lift pipe 123 from the treated water tank 117 is sent to the sewage treatment apparatus D ₂ via the transfer pipe 122, and after phosphoric acid removal and nitrogen removal are performed, It is returned to the first anaerobic filtration tank 104.

According to the invention as set forth in claim 1, at least a portion of the sewage storage tank and the sewage stored in the sewage storage tank is disposed so as to be immersed, and at least an iron or aluminum ion eluted by electrolysis to precipitate and remove phosphoric acid in the sewage. And a set of electrodes, a power supply for supplying an electrolytic current to these electrodes, and a control unit for controlling the power supply, wherein at least a part of each electrode is a carrier for reproducing microorganisms involved in denitrification in sewage. And the control unit periodically reverses the polarity of the electrode, and the phosphoric acid is removed from the electrode side of the positive polarity, and the denitrification based on the microorganisms in the carrier on the electrode side of the polarity negative electrode. Removal of nitrogen by reaction is performed.

Therefore, phosphoric acid removal and nitrogen removal can be performed in parallel.

According to the invention described in claim 2, the carrier is made of a porous network made of plastic, carbon fiber, or sintered ceramic, and is attached at the upper edge of each electrode, or an electrode case for storing a set of electrodes. Lies on the bottom side.

Therefore, the said effect which the invention of Claim 1 shows can be reliably ensured by a simple structure.

According to the invention set forth in claim 3, there is provided a partition plate for partitioning a set of electrodes between the anode side and the cathode side, and an aeration device for aeration of each electrode, and the control unit also controls the aeration device to have a polarity. It is comprised so that aeration may be performed only to the electrode which consists of an anode.

Therefore, in addition to the above-described effect of the invention described in claim 1, the aeration device aerations only on the electrode on the anode side, promotes the phosphoric acid removal reaction on the anode side, and simultaneously cleans the electrode. The electrode on the cathode side can be placed in a reducing atmosphere.

According to the invention as set forth in claim 4, there is further provided an introduction pipe for introducing wastewater into the wastewater storage tank, wherein the partition plate in the wastewater storage tank flows the wastewater from the introduction pipe into the wastewater storage tank via one end of the partition plate. Arranged to guide the other end along one side or the other side of the partition plate, and then turn the other end to flow out through one end along the other side or one side, between the introduction tube and the sewage storage tank, A flow path switching valve is also provided for diverting the wastewater from the discharge plate to be guided along one of the side and the other side of the partition plate, and the control unit controls the flow path switching valve again so that the wastewater from the inlet pipe is negatively polarized. It is comprised so that it may flow in to the side of the partition plate with an electrode first.

Therefore, the sewage flowing into the sewage storage tank then proceeds toward the side of the partition plate with the anode electrode after turning the other end of the partition plate, and after sufficient denitrification reaction is performed on the cathode side with relatively low dissolved oxygen concentration, The agglomeration reaction and cleaning of the electrode can be performed at the anode side where the dissolved oxygen concentration is increased.

Claims (4)

A sewage storage tank and at least one electrode disposed so as to be immersed in at least a portion of the sewage stored in the sewage storage tank, and at least one electrode which elutes iron ions or aluminum ions by electrolysis to precipitate and remove phosphoric acid in the sewage; It has a power supply for supplying a current and a control unit for controlling the power supply, At least a portion of each electrode is covered with a carrier for reproductive microorganisms involved in the denitrification reaction in sewage, The control unit periodically reverses the polarity of the electrode, and the phosphoric acid is removed from the electrode side of which the polarity is positive, and nitrogen from the denitrification reaction based on the microorganisms in the carrier is of the electrode side of the polarity of the negative electrode. Sewage treatment apparatus, characterized in that the removal of the. The method of claim 1, The carrier, Sewage treatment characterized in that it consists of a porous network of plastics, carbon fibers or sintered ceramics, and is attached to the upper edge of each electrode or placed on the bottom of an electrode case for accommodating a set of electrodes. Device. The method according to claim 1 or 2, A partition plate for partitioning a set of electrodes between the anode side and the cathode side, and an aeration device for aeration of each electrode; The control unit also controls the aeration device, wherein the wastewater treatment device is characterized in that the aeration is carried out only on the electrode having a positive polarity. The method of claim 3, Also provided with an inlet pipe for introducing wastewater into the wastewater storage tank, The partition plate in the sewage storage tank flows sewage from the introduction pipe into the sewage storage tank via one end of the partition plate and guides it to the other end along one side or the other side of the partition plate, and then turns the other end to the other side. Or arranged to flow along one side via one end, Between the introduction pipe and the sewage storage tank, there is also provided a flow path switching valve for diverting the waste water from the introduction pipe to be guided along one of the one side and the other side of the partition plate, The control unit again controls the flow path switching valve, so that the effluent from the inlet pipe first flows into the side of the partition plate with the electrode of the negative polarity.