Wastewater treatment apparatus and wastewater treatment method

Abstract

To provide a wastewater treatment apparatus capable of efficiently performing nitrification reaction.SOLUTION: A wastewater treatment apparatus 10 performing a nitrification reaction of converting ammonia involved in to-be-treated water to nitrous acid or nitric acid in the presence of oxygen and a denitrification reaction of nitrous acid or nitric acid generated based on the nitrification reaction to nitrogen in the absence of oxygen is assembled with a membrane separation apparatus 3 for separating and removing a solid involved in to-be-treated water having been applied with the nitrification reaction and denitrification reaction, an air diffuser 4a moving to-be-treated water upwardly relative to the vertical direction and diffusing bubbles for washing the membrane separation apparatus 3, and an air diffuser 4b moving to-be-treated water upwardly relative to the vertical direction and diffusing bubbles passing through peripheries of the membrane separation apparatus 3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a wastewater treatment apparatus and a wastewater treatment method.

Background Art

[0002] Conventionally, there has been known a wastewater treatment apparatus that performs a nitrification reaction of converting ammonia contained in wastewater into nitrous acid or nitric acid in the presence of oxygen and a denitrification reaction of converting nitrous acid or nitric acid into nitrogen in an oxygen-free state in a single reaction tank (see, for example, Patent Document 1). In the wastewater treatment apparatus of Patent Document 1, the reaction tank is provided with a partition plate that divides the tank into a nitrification reaction region where the nitrification reaction is performed and a denitrification reaction region where the denitrification reaction is performed. The nitrification reaction region includes a membrane separation device that separates and removes solids contained in the wastewater (hereinafter referred to as "treated water") in which the nitrification reaction and the denitrification reaction have been performed, and a diffuser device that cleans the surface of the membrane separation device or diffuses bubbles for supplying air necessary for the nitrification reaction.

[0003] When the water level of the wastewater is higher than the upper end of the partition plate, the wastewater overflows the partition plate and moves from the nitrification reaction region to the denitrification reaction region, and returns from the denitrification reaction region to the nitrification reaction region. As a result, a circulating flow is formed around the partition plate. Therefore, nitrous acid or nitric acid generated in the nitrification reaction region moves to the denitrification reaction region and is converted into nitrogen in the denitrification reaction region. On the other hand, when the water level of the wastewater is lower than the upper end of the partition plate, the wastewater does not overflow the partition plate. Therefore, no circulating flow is formed, nitrous acid or nitric acid is generated in the nitrification reaction region, and nitrous acid or nitric acid that has previously moved from the nitrification reaction region to the denitrification reaction region is converted into nitrogen in the denitrification reaction region.

[0004] By the way, the diffuser device supplies a large amount of minute bubbles having an air diameter of, for example, 20 to 500 μm to the nitrification reaction region. Oxygen contained in the minute bubbles diffused in the nitrification reaction region dissolves in the wastewater, and the dissolved oxygen concentration necessary for the nitrification reaction is ensured.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, since the aeration device aerates minute bubbles to the membrane separation device installed in the nitrification reaction region, the minute bubbles coalesce as they pass through the membrane separation device to form large bubbles. Since large bubbles are difficult to dissolve in sewage, there has been a problem that the dissolved oxygen concentration required for the nitrification reaction cannot be ensured and the nitrification reaction cannot be efficiently carried out.

[0007] An object of the present invention is to provide a wastewater treatment apparatus and a wastewater treatment method capable of efficiently performing a nitrification reaction.

Means for Solving the Problems

[0008] In order to achieve the above object, the wastewater treatment apparatus of the present invention includes a nitrification reaction for converting ammonia contained in wastewater into nitrous acid or nitric acid in the presence of oxygen, and a denitrification reaction for converting nitrous acid or nitric acid generated based on the nitrification reaction into nitrogen in an anaerobic state, in a wastewater treatment apparatus that performs: Partitioning means for partitioning a nitrification reaction region that performs the nitrification reaction and a denitrification reaction region that performs the denitrification reaction, the partitioning means being curved or bent, or inclined with respect to the vertical direction, and the nitrification reaction region is a membrane separation device that separates solids contained in the wastewater subjected to the nitrification reaction and the denitrification reaction; a first aeration means that moves the wastewater upward in the vertical direction and aerates bubbles for cleaning the membrane separation device; and a second aeration means that moves the wastewater upward in the vertical direction and passes around the membrane separation device colliding with the partitioning means together with characterized by comprising aerating bubbles. In addition, in order to achieve the above object, the wastewater treatment apparatus of the present invention is a wastewater treatment apparatus that performs a nitrification reaction for converting ammonia contained in wastewater into nitrous acid or nitric acid in the presence of oxygen and a denitrification reaction for converting nitrous acid or nitric acid generated based on the nitrification reaction into nitrogen in an anaerobic state. Partitioning means for partitioning a nitrification reaction region that performs the nitrification reaction and a denitrification reaction region that performs the denitrification reaction, the partitioning means having one end located between the highest water level and the lowest water level set in the wastewater treatment apparatus, and the other end located near the bottom of the wastewater treatment apparatus. The area surrounded by the other end is 125% or more and 350% or less of the area surrounded by the one end. The nitrification reaction region includes a membrane separation device for separating solids contained in the wastewater subjected to the nitrification reaction and the denitrification reaction, a first air diffusing means for diffusing bubbles that move the wastewater upward in the vertical direction and wash the membrane separation device, and a second air diffusing means for diffusing bubbles that move the wastewater upward in the vertical direction, pass around the membrane separation device, and collide with the partitioning means. In addition, in order to achieve the above object, the wastewater treatment apparatus of the present invention is a wastewater treatment apparatus that performs a nitrification reaction of converting ammonia contained in wastewater into nitrous acid or nitric acid in the presence of oxygen and a denitrification reaction of converting nitrous acid or nitric acid generated based on the nitrification reaction into nitrogen in an anaerobic state. The wastewater treatment apparatus is provided with a partitioning means for partitioning a nitrification reaction region that performs the nitrification reaction and a denitrification reaction region that performs the denitrification reaction. The nitrification reaction region includes a membrane separation device that separates solids contained in the wastewater subjected to the nitrification reaction and the denitrification reaction, a first air diffusing means that diffuses air bubbles that move the wastewater upward in the vertical direction and wash the membrane separation device, and a second air diffusing means that diffuses air bubbles that move the wastewater upward in the vertical direction, pass around the membrane separation device, and collide with the partitioning means. The denitrification reaction region that performs the denitrification reaction is characterized by having a rectifying member that protrudes from the inner wall of the wastewater treatment apparatus toward the partitioning means. 。

[0009] In order to achieve the above object, the wastewater treatment method of the present invention includes a nitrification reaction for converting ammonia contained in wastewater into nitrous acid or nitric acid in the presence of oxygen, and a denitrification reaction for converting nitrous acid or nitric acid generated based on the nitrification reaction into nitrogen in an anaerobic state, and is executed by a wastewater treatment apparatus including a membrane separation device for separating and removing solids contained in the wastewater subjected to the nitrification reaction and the denitrification reaction. In the wastewater treatment method, The wastewater treatment apparatus is a partitioning means for partitioning a nitrification reaction region that performs the nitrification reaction and a denitrification reaction region that performs the denitrification reaction, and is provided with partitioning means that is curved or bent, or inclined with respect to the vertical direction. The nitrification reaction region includes the membrane separation device, a first air diffusing means that diffuses air bubbles that move the wastewater upward in the vertical direction and wash the membrane separation device, and a second air diffusing means that diffuses air bubbles that move the wastewater upward in the vertical direction, pass around the membrane separation device, and collide with the partitioning means. The wastewater treatment method is as follows. it has a first air diffusing step of diffusing air bubbles that move the wastewater upward in the vertical direction to clean the membrane separation device, and a second air diffusing step of diffusing air bubbles that move the wastewater upward in the vertical direction and pass around the membrane separation device. In addition, in order to achieve the above object, the wastewater treatment method of the present invention includes a nitrification reaction for converting ammonia contained in wastewater into nitrous acid or nitric acid in the presence of oxygen, and a denitrification reaction for converting nitrous acid or nitric acid generated based on the nitrification reaction into nitrogen in an anaerobic state. In the wastewater treatment method performed by a wastewater treatment apparatus including a membrane separation apparatus for separating and removing solids contained in the wastewater subjected to the nitrification reaction and the denitrification reaction, the wastewater treatment apparatus includes a partitioning means for partitioning a nitrification reaction region for performing the nitrification reaction and a denitrification reaction region for performing the denitrification reaction, the partitioning means having one end portion located between the highest water level and the lowest water level set in the wastewater treatment apparatus, and the other end portion located near the bottom of the wastewater treatment apparatus, the area surrounded by the other end portion being 125% or more and 350% or less of the area surrounded by the one end portion, the nitrification reaction region including the membrane separation apparatus, a first air diffusing means for diffusing bubbles that move the wastewater upward in the vertical direction and clean the membrane separation apparatus, and a second air diffusing means for diffusing bubbles that move the wastewater upward in the vertical direction, pass around the membrane separation apparatus, and collide with the partitioning means, the wastewater treatment method including a first air diffusing step for diffusing bubbles that move the wastewater upward in the vertical direction and clean the membrane separation apparatus, and a second air diffusing step for diffusing bubbles that move the wastewater upward in the vertical direction and pass around the membrane separation apparatus. Further, in order to achieve the above object, the wastewater treatment method of the present invention includes a nitrification reaction of converting ammonia contained in wastewater into nitrous acid or nitric acid in the presence of oxygen, and a denitrification reaction of converting nitrous acid or nitric acid generated based on the nitrification reaction into nitrogen in an anaerobic state. The wastewater treatment method is carried out by a wastewater treatment apparatus including a membrane separation device for separating and removing solids contained in the wastewater subjected to the nitrification reaction and the denitrification reaction. In the wastewater treatment apparatus, a partitioning means for partitioning a nitrification reaction region for carrying out the nitrification reaction and a denitrification reaction region for carrying out the denitrification reaction is provided. The nitrification reaction region includes the membrane separation device, a first air diffusing means for diffusing bubbles that move the wastewater upward in the vertical direction and clean the membrane separation device, and a second air diffusing means for diffusing bubbles that move the wastewater upward in the vertical direction, pass around the membrane separation device, and collide with the partitioning means. The denitrification reaction region has a rectifying member protruding from the inner wall of the wastewater treatment apparatus toward the partitioning means. The wastewater treatment method includes a first air diffusing step of diffusing bubbles that move the wastewater upward in the vertical direction and clean the membrane separation device, and a second air diffusing step of diffusing bubbles that move the wastewater upward in the vertical direction and pass around the membrane separation device.

Effect of the Invention

[0010] According to the present invention, the nitrification reaction can be efficiently executed.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0013] FIG. 1 is a schematic diagram showing the configuration of a wastewater treatment apparatus 10 according to an embodiment of the present invention.

[0014] The wastewater treatment apparatus 10 of FIG. 1 includes a raw water tank 1, a reaction tank 2, pumps P1 and P2, a liquid level sensor LS, and a blower B. The reaction tank 2 has a membrane separation device 3, an air diffuser 4, a partition plate 5 (partitioning means), and a rectifying plate 6 (rectifying member). The raw water tank 1 and the pump P1, the pump P1 and the liquid level sensor LS, the blower B and the air diffuser 4, and the pump P2 and the membrane separation device 3 are connected.

[0015] The raw water tank 1 stores the water to be treated for supply to the reaction tank 2. The reaction tank 2 subjects the water to be treated supplied from the raw water tank 1 to a nitrification reaction that converts ammonia contained in the water to be treated into nitrous acid or nitric acid in the presence of oxygen, and a denitrification reaction that converts nitrous acid or nitric acid into nitrogen in an anaerobic state. The nitrification reaction is carried out by nitrifying bacteria, which are organic sludge containing microorganisms (hereinafter referred to as "activated sludge"), and the denitrification reaction is carried out by denitrifying bacteria, which are activated sludge. In the reaction tank 2, a maximum water level HWL for stopping the supply of the water to be treated from the raw water tank 1 and a minimum water level LWL for starting the supply of the water to be treated from the raw water tank 1 are set. For example, when the liquid level sensor LS detects the minimum water level LWL with respect to the water level of the water to be treated, the pump P1 is driven to start the supply of the water to be treated from the raw water tank 1 to the reaction tank 2, and when the liquid level sensor LS detects the maximum water level HWL with respect to the water level of the water to be treated, the pump P1 stops and the supply of the water to be treated from the raw water tank 1 to the reaction tank 2 is stopped.

[0016] The reaction tank 2 is divided into two regions by the partition plate 5. Specifically, it is divided into a nitrification reaction region D1 surrounded by the partition plate 5 where nitrification reaction is carried out on the water to be treated, and a denitrification reaction region D2 surrounded by the partition plate 5 and the side wall of the reaction tank 2 where denitrification reaction is carried out on the water to be treated. The membrane separation device 3 and the air diffuser 4 are arranged in the nitrification reaction region D1, and the air diffuser 4 is arranged between the membrane separation device 3 and the bottom of the reaction tank 2. The flow straightening plate 6 is arranged in the denitrification reaction region D2 and protrudes from the side surface of the reaction tank 2 toward the partition plate 5.

[0017] When the pump P2 is driven, the treated water subjected to the nitrification reaction and the denitrification reaction is discharged out of the reaction tank 2 via the membrane separation device 3. The membrane separation device 3 is composed of, for example, a plurality of hollow fiber membranes, and the solid content contained in the treated water is separated and removed when passing through the membrane separation device 3. The blower B supplies air to the air diffuser 4, and the air diffuser 4 diffuses a large amount of minute air with an air diameter of 20 to 500 μm into the nitrification reaction region D1.

[0018] One end of the partition plate 5 (hereinafter referred to as "the upper end portion 5a of the partition plate") is located between the highest water level HWL and the lowest water level LWL, and the other end of the partition plate 5 (hereinafter referred to as "the lower end portion 5b of the partition plate") is located near the bottom of the reaction tank 2. When the water level of the water to be treated is between the highest water level HWL and the upper end portion 5a of the partition plate, the water to be treated overflows the upper end portion 5a of the partition plate and moves from the nitrification reaction region D1 to the denitrification reaction region D2, and at the same time, returns from the denitrification reaction region D2 to the nitrification reaction region D1 via the space between the lower end portion 5b of the partition plate and the bottom of the reaction tank 2. Thereby, a circulating flow is formed around the partition plate 5. In the nitrification reaction region D1, nitrous acid and nitric acid are generated by the nitrification reaction and move to the denitrification reaction region D2 by the circulating flow. In the denitrification reaction region D2, nitrogen is generated by the denitrification reaction based on the nitrous acid and nitric acid that have moved to the denitrification reaction region D2.

[0019] When the water level of the water to be treated is between the lowest water level LWL and the upper end 5a of the partition plate, no circulation flow is formed. Therefore, there is no nitrous acid and nitric acid newly moving from the nitrification reaction region D1 to the denitrification reaction region D2. In the nitrification reaction region D1, nitrous acid and nitric acid are generated by the nitrification reaction, and in the denitrification reaction region D2, nitrogen is generated by the denitrification reaction. The denitrification reaction region D2 is preferably 50% to 200% by volume, more preferably 75% to 150% by volume, of the nitrification reaction region D1, so that both the nitrification reaction and the denitrification reaction are carried out without waste.

[0020] In the partition plate 5, the area surrounded by the lower end 5b of the partition plate only needs to be larger than the area surrounded by the upper end 5a of the partition plate. For example, the partition plate 5 is composed of at least one plate-like member whose lower end 5b side is bent in a "く" shape in the direction of the tank wall of the reaction tank 2. Note that the partition plate 5 may also be composed of at least one plate-like member whose lower end 5b side is curved in a "ノ" shape in the direction of the tank wall of the reaction tank 2 (Fig. 2(a)). Further, the partition plate 5 may be formed in a frustum shape by at least one flat plate-like member inclined in both the vertical direction and the horizontal direction, for example (Fig. 2(b)). The area surrounded by the lower end 5b of the partition plate is preferably 125% to 350%, more preferably 150% to 300%, of the area surrounded by the upper end 5a of the partition plate.

[0021] FIG. 3 is a plan view of the reaction tank 2 in FIG. 1.

[0022] In FIG. 3, the air diffuser 4 is composed of an air diffuser 4a (first air diffusing means, FIG. 4(a)) disposed directly below the membrane separation device 3, and an air diffuser 4b (second air diffusing means, FIG. 4(b)) disposed other than directly below the membrane separation device 3 in the nitrification reaction region D1. At least a part of the air diffuser 4b is disposed directly below the bent portion of the partition plate 5. The bubbles diffused by the air diffuser 4a move upward with respect to the vertical direction of the water to be treated and collide with the surface of the membrane separation device 3. Thereby, the membrane separation device 3 is cleaned and fouling of the hollow fiber membrane is suppressed. The minute bubbles diffused by the air diffuser 4b collide with the lower part of the partition plate 5 and move upward with respect to the vertical direction of the water to be treated, and are discharged from the water surface while contacting the water to be treated without causing bubble coalescence due to collision with the surface of the membrane separation device 3.

[0023] FIG. 5 is a flowchart showing the procedure of the wastewater treatment executed by the wastewater treatment device 10 of FIG. 1.

[0024] In the wastewater treatment (wastewater treatment method) of FIG. 5, first, the water to be treated is supplied from the raw water tank 1 to the reaction tank 2, and the pump P1 is stopped when the water level of the water to be treated in the reaction tank 2 reaches the maximum water level HWL (S1). The air diffusers 4a and 4b diffuse bubbles (S2). Specifically, the air diffuser 4a diffuses bubbles for cleaning the membrane separation device 3 by colliding with the membrane separation device 3 (first air diffusing step), and the air diffuser 4b diffuses minute bubbles passing around the membrane separation device 3 (second air diffusing step). Thereby, the water to be treated in the nitrification reaction region D1 overflows the upper end portion of the partition plate and moves to the denitrification reaction region D2, and returns from the denitrification reaction region D2 to the nitrification reaction region D1 via between the lower end portion 5b of the partition plate and the bottom of the reaction tank 2, and a circulation flow is formed that circulates around the partition plate 5 (S3).

[0025] When a circulating flow is formed, in the nitrification reaction region D1, a nitrification reaction is performed on the water to be treated, and in the denitrification reaction region D2, a denitrification reaction is performed on the water to be treated. As a result, treated water is generated, and the treated water is discharged outside the reaction tank 2 via the membrane separation device 3. When the treated water is discharged outside the reaction tank 2, the water level of the water to be treated drops and is located between the upper end 5a of the partition plate and the lowest water level LWL, and the circulating flow disappears (S4).

[0026] Even when the circulating flow is not formed, in the nitrification reaction region D1, a nitrification reaction is performed on the water to be treated, and in the denitrification reaction region D2, a denitrification reaction is performed on the water to be treated, and the treated water is discharged outside the reaction tank 2 via the membrane separation device 3 (S5). The water level of the water to be treated reaches the lowest water level LWL, the pump P1 is driven, and new water to be treated is supplied from the raw water tank 1 to the reaction tank 2 (S6), and this treatment ends.

[0027] According to the wastewater treatment of FIG. 5, the air diffuser 4a diffuses bubbles for cleaning the membrane separation device 3 by colliding with the membrane separation device 3, and the air diffuser 4b diffuses minute bubbles passing around the membrane separation device 3 (S2). The bubbles diffused by the air diffuser 4a coalesce as they pass through the membrane separation device 3 and the bubbles become larger, but the minute bubbles diffused by the air diffuser 4b come into contact with the water to be treated without coalescing and are released from the water surface of the water to be treated. As a result, the oxygen contained in the minute bubbles based on the air diffuser 4b is sufficiently dissolved in the water to be treated, so that the dissolved oxygen concentration required for the nitrification reaction is ensured, and thus the nitrification reaction can be efficiently carried out. In addition, since the oxygen contained in the minute bubbles based on the air diffuser 4b is surely dissolved in the water to be treated, the dissolved oxygen concentration required for the nitrification reaction can be quickly ensured, and thus the power consumption used for the air diffuser 4 can be suppressed.

[0028] In this embodiment, the partition plate 5 is not simply a cylindrical shape, and the area surrounded by the lower end portion 5b of the partition plate is configured to be 125% or more and 350% or less of the area surrounded by the upper end portion 5a of the partition plate. Thereby, while ensuring the scale of the circulation flow formed around the partition plate 5 to an extent that enables efficient nitrification reaction and denitrification reaction, it is possible to secure an installation space for the aeration device 4b used to ensure the dissolved oxygen concentration required for the nitrification reaction. Further, since the distance between the lower end portion 5b of the partition plate and the corner portion 2a (FIG. 1) at the bottom of the reaction tank 2 is narrower than when the partition plate extends along the vertical direction, the flow velocity of the water to be treated passing between the lower end portion 5b of the partition plate and the corner portion 2a becomes higher than in that case. As a result, the denitrifying bacteria are dispersed in the water to be treated without accumulating in the corner of the reaction tank 2, so that the denitrification reaction is efficiently carried out.

[0029] Note that the water to be treated must be subjected to nitrification reaction and denitrification reaction. However, when the partition plate 5 is used in the reaction tank 2, there is a possibility that the nitrification reaction region D1 expands and the denitrification reaction region D2 contracts. In response to this, in this embodiment, in order to appropriately perform the nitrification reaction and the denitrification reaction on the water to be treated, based on past performance, the denitrification reaction region is set to be 50% by volume or more and 200% by volume or less of the nitrification reaction region.

[0030] By the way, in this embodiment, in the denitrification reaction region D2, a rectifying plate 6 protrudes from the inner wall of the reaction tank 2 toward the partition plate 5. Specifically, the rectifying plate 6 is installed above the lower end portion 5b of the partition plate 5 and protrudes from the inner wall of the reaction tank 2 toward the lower portion of the partition plate 5. The rectifying plate 6 is, for example, a rectangular plate, and one end of the long side is fixed to the inner wall of the reaction tank 2. The long side of the rectifying plate 6 is, for example, 1 / 2 to 5 / 4 of the lateral width of the partition plate, preferably 3 / 4 to 1. Thereby, when a circulation flow is formed, a swirling flow is generated in the denitrification reaction region D2 (FIG. 6), and the denitrifying bacteria are uniformly mixed in the water to be treated in the denitrification reaction region D2, so that the denitrification reaction can be efficiently carried out. Further, since a swirling flow is generated in the denitrification reaction region D2, it is not necessary to install a stirrer for stirring the water to be treated in the denitrification reaction region D2, and it is possible to prevent the generation of unnecessary power consumption.

[0031] The embodiments of the present invention have been described above, but the present invention is not limited to these embodiments in any way.

Explanation of Reference Numerals

[0032] 10 Wastewater treatment device 3 Membrane separation device 4, 4a, 4b Aeration device 5 Partition plate

Claims

1. In a wastewater treatment apparatus that performs a nitrification reaction of converting ammonia contained in wastewater into nitrous acid or nitric acid in the presence of oxygen and a denitrification reaction of converting the nitrous acid or nitric acid generated based on the nitrification reaction into nitrogen in an anaerobic state, partitioning means for partitioning a nitrification reaction region that performs the nitrification reaction and a denitrification reaction region that performs the denitrification reaction, the partitioning means being curved or bent, or inclined with respect to the vertical direction, the nitrification reaction region is a membrane separation device that separates solids contained in the wastewater subjected to the nitrification reaction and the denitrification reaction, first air diffusing means for diffusing air bubbles that move the wastewater upward in the vertical direction and clean the membrane separation device, second air diffusing means for diffusing air bubbles that move the wastewater upward in the vertical direction, pass around the membrane separation device, and collide with the partitioning means, and a wastewater treatment apparatus characterized by comprising the same.

2. In a wastewater treatment apparatus that performs a nitrification reaction of converting ammonia contained in wastewater into nitrous acid or nitric acid in the presence of oxygen and a denitrification reaction of converting the nitrous acid or nitric acid generated based on the nitrification reaction into nitrogen in an anaerobic state, partitioning means for partitioning a nitrification reaction region that performs the nitrification reaction and a denitrification reaction region that performs the denitrification reaction, the partitioning means having one end located between the highest water level and the lowest water level set in the wastewater treatment apparatus and the other end located near the bottom of the wastewater treatment apparatus, and the area surrounded by the other end being 125% or more and 350% or less of the area surrounded by the one end, the nitrification reaction region is a membrane separation device that separates solids contained in the wastewater subjected to the nitrification reaction and the denitrification reaction, first air diffusing means for diffusing air bubbles that move the wastewater upward in the vertical direction and clean the membrane separation device, second air diffusing means for diffusing air bubbles that move the wastewater upward in the vertical direction, pass around the membrane separation device, and collide with the partitioning means, and a wastewater treatment apparatus characterized by comprising the same.

3. In a wastewater treatment apparatus that performs a nitrification reaction of converting ammonia contained in wastewater into nitrous acid or nitric acid in the presence of oxygen and a denitrification reaction of converting the nitrous acid or nitric acid generated based on the nitrification reaction into nitrogen in an anaerobic state, It is provided with a partitioning means for partitioning a nitrification reaction region for carrying out the nitrification reaction and a denitrification reaction region for carrying out the denitrification reaction. The nitrification reaction region is a membrane separation device for separating solids contained in the wastewater subjected to the nitrification reaction and the denitrification reaction, a first air diffusing means for diffusing air bubbles that move the wastewater upward in the vertical direction and clean the membrane separation device, a second air diffusing means for diffusing air bubbles that move the wastewater upward in the vertical direction, pass around the membrane separation device, and collide with the partitioning means. The denitrification reaction region for carrying out the denitrification reaction has a rectifying member protruding from the inner wall of the wastewater treatment device toward the partitioning means. A wastewater treatment device characterized by this.

4. In a wastewater treatment method carried out by a wastewater treatment device that performs a nitrification reaction for converting ammonia contained in wastewater into nitrous acid or nitric acid in the presence of oxygen and a denitrification reaction for converting nitrous acid or nitric acid generated based on the nitrification reaction into nitrogen in an anaerobic state, and is provided with a membrane separation device for separating and removing solids contained in the wastewater subjected to the nitrification reaction and the denitrification reaction, the wastewater treatment device is provided with a partitioning means for partitioning a nitrification reaction region for carrying out the nitrification reaction and a denitrification reaction region for carrying out the denitrification reaction, the partitioning means being curved or bent, or inclined with respect to the vertical direction. The nitrification reaction region includes the membrane separation device, a first air diffusing means for diffusing air bubbles that move the wastewater upward in the vertical direction and clean the membrane separation device, and a second air diffusing means for diffusing air bubbles that move the wastewater upward in the vertical direction, pass around the membrane separation device, and collide with the partitioning means. The wastewater treatment method is a first air diffusing step of diffusing air bubbles that move the wastewater upward in the vertical direction and clean the membrane separation device, a second air diffusing step of diffusing air bubbles that move the wastewater upward in the vertical direction and pass around the membrane separation device. A wastewater treatment method characterized by having this. Claim 5. A wastewater treatment method executed by a wastewater treatment apparatus including a membrane separation apparatus that performs a nitrification reaction of converting ammonia contained in wastewater into nitrous acid or nitric acid in the presence of oxygen and a denitrification reaction of converting the nitrous acid or nitric acid generated based on the nitrification reaction into nitrogen in an anaerobic state, and separating and removing solid matter contained in the wastewater subjected to the nitrification reaction and the denitrification reaction, wherein: the wastewater treatment apparatus includes partitioning means for partitioning a nitrification reaction region that performs the nitrification reaction and a denitrification reaction region that performs the denitrification reaction, the partitioning means having one end located between the maximum water level and the minimum water level set in the wastewater treatment apparatus and the other end located near the bottom of the wastewater treatment apparatus, and the area surrounded by the other end being 125% or more and 350% or less of the area surrounded by the one end; the nitrification reaction region includes the membrane separation apparatus, first aeration means for aerating bubbles that move the wastewater upward in the vertical direction and clean the membrane separation apparatus, and second aeration means for aerating bubbles that move the wastewater upward in the vertical direction, pass around the membrane separation apparatus, and collide with the partitioning means; the wastewater treatment method includes: a first aeration step of aerating bubbles that move the wastewater upward in the vertical direction and clean the membrane separation apparatus; and a second aeration step of aerating bubbles that move the wastewater upward in the vertical direction and pass around the membrane separation apparatus, characterized in that the wastewater treatment method has the second aeration step. Claim 6. A wastewater treatment method executed by a wastewater treatment apparatus including a membrane separation apparatus that performs a nitrification reaction of converting ammonia contained in wastewater into nitrous acid or nitric acid in the presence of oxygen and a denitrification reaction of converting the nitrous acid or nitric acid generated based on the nitrification reaction into nitrogen in an anaerobic state, and separating and removing solid matter contained in the wastewater subjected to the nitrification reaction and the denitrification reaction, wherein: the wastewater treatment apparatus includes partitioning means for partitioning a nitrification reaction region that performs the nitrification reaction and a denitrification reaction region that performs the denitrification reaction; the nitrification reaction region includes the membrane separation apparatus, first aeration means for aerating bubbles that move the wastewater upward in the vertical direction and clean the membrane separation apparatus, and second aeration means for aerating bubbles that move the wastewater upward in the vertical direction, pass around the membrane separation apparatus, and collide with the partitioning means; The denitrification reaction region has a rectifying member protruding from the inner wall of the wastewater treatment device toward the partitioning means, The wastewater treatment method is, a first air diffusing step of diffusing air bubbles that move the wastewater upward in the vertical direction and clean the membrane separation device, and a second air diffusing step of diffusing air bubbles that move the wastewater upward in the vertical direction and pass around the membrane separation device, and is characterized by having the above steps.

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