JPH10296281A - Waste water treating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a carrier from becoming impossible to gravitationally separated due to adhesion of thread-like microbes on the carrier by agitating the carrier in all parts of a biological reaction tank. SOLUTION: A carrier 13 carrying microorganisms together with raw water is made to flow along a bottom face 11a of a biological reaction tank 11 by an underwater agitator 14 installed on the bottom face 11a of the biological reaction tank 11 and is made to flow into an ascending flow path 11e provided along a vertical direction. The raw water flowing into the ascending flow path 11e is subjected to aeration with aerating air through an air feeding pipe 15c of an aerator 15 while being made to move upward and is discharged from an top end of the ascending flow path 11e to an upper part of the biological reaction tank 11. Ammonium nitrogen in the raw water is subjected to oxidation treatment with the microorganisms carried by the carrier 13 while moving upward within the ascending flow path 11e. Water discharged from the flow path 11e is treated to gravitationally separate the carrier 13 in the upper part of the biological reaction tank 11 and is allowed to overflow into an outflow path 11f.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wastewater treatment system for biologically treating wastewater such as public sewage and industrial wastewater by microorganisms carried on a carrier.

[0002]

2. Description of the Related Art Wastewater such as public sewage and factory wastewater is usually
Wastewater treatment facilities are purifying wastewater, and recently, in order to more reliably prevent environmental pollution, improvement of the treatment capacity of sewage treatment facilities and the like and improvement of the quality of treated water have been carried out. Has been requested. To this end, wastewater treatment facilities employ a biological treatment method in which BOD (biological oxygen demand) and ammonia nitrogen in wastewater are reduced using microorganisms. In one of such biological treatment methods, a carrier carrying microorganisms is suspended in wastewater in a biological reaction tank, and under aerobic conditions, the microorganisms carried on the carrier are drained. There is a way to handle. In this case, the BOD is oxidatively decomposed by activated sludge floating in the wastewater, and the ammonia nitrogen is oxidized to nitrite or nitric acid by microorganisms such as nitrifying bacteria carried on the carrier.

In such a biological treatment method, the processing capacity can be improved by increasing the size of the biological reaction tank. However, in urban areas, since it is difficult to construct a sewage treatment facility with a large site area, it is necessary to increase the water depth of the biological reaction tank to about 7m to several tens of meters to improve the treatment capacity. Has been done. In such a deep-type biological reaction tank, microorganisms are supported on a support of about several mm by entrapping or binding the microorganisms, and are disposed at a ratio of 5 to 20% by volume with respect to the treated sewage. Thus, air is supplied from the entire bottom surface of the biological reaction tank for aeration.

[0004] In this case, the BOD concentration of 200 mg / l is reduced to 10 mg / l or less while the carrier carrying microorganisms is suspended in sewage, and 40 mg / l of ammonia nitrogen is reduced to 2 mg / l. In order to reduce to below
About 6 m ³ of aerated air is required per 1 m ^{3 of} sewage.
Usually, the discharge pressure of a blower used for aeration is about 7000 mm at a maximum of a water column pressure.
In the above-mentioned biological reaction tank, in order to aerate the entire bottom surface, a special-purpose blower having an increased discharge pressure is required. As a result, the blower itself becomes expensive, and the power consumption by the blower also increases, thereby impairing economic efficiency.

[0005] Further, when aeration treatment is performed at a deep water portion, the amount of air dissolved in water increases. However,
If a large amount of air dissolves in water, the dissolved sedimentation tank in the later stage separates as fine bubbles, and air adheres to suspended solids in the water, which may hinder sedimentation and separation of suspended solids. There is.

In order to solve such a problem, the biological reaction tank is divided into upper and lower stages, only the wastewater flowing into the upper stage is aerated, and the wastewater flowing into the lower stage is denitrified under anaerobic conditions. An apparatus has been proposed. However, in this case, the structure of the biological reaction tank becomes complicated. In addition, since the lower part is covered by the upper part, there is also a problem that maintenance is not easy.

On the other hand, the inside of the biological reaction tank is divided into two processing chambers by a vertical partition plate, and the respective processing chambers communicate with each other on the upper and lower sides of the partition plate. Wastewater treatment systems have also been developed that include an aeration device in the treatment chamber. In this case, since the water rises in the processing chamber in which the aeration device is arranged, and flows into the other processing chamber through the upper side of the partition plate, the carrier is included in the biological reaction tank. The drained water will circulate.

However, in such a configuration, the water does not flow sufficiently at the corner of the bottom of the biological reaction tank,
Carriers may be deposited at the corners. If the flow rate of water is increased to prevent the accumulation of the carrier at the corners, the carrier itself will be worn and cannot be used stably for a long time.

In addition, a plurality of cylindrical rising channels are provided inside the biological reaction tank, and an aeration device is arranged in each of the rising channels. Wastewater treatment systems have been developed in which concave grooves are gradually narrowed as much as possible. In such a configuration, the water in each ascending flow path flows upward by the aeration device, and is discharged from the upper end of each ascending flow path. Then, the carrier contained in the water discharged from each ascending flow path is separated by gravity and settles. The settled carrier flows into each groove below the ascending flow channel, flows into each ascending flow channel together with water, and the carrier is circulated together with the water.

[0010]

In a biological reaction tank for treating wastewater, a large amount of small animals (official name: Epistylis urceolata) having a size of about 70 to 190 μm, which are called hanging insects, may be generated. When such a small animal adheres to the carrier contained in the water of the biological reaction tank, the apparent specific gravity of the carrier decreases by about 0.1 to 0.2. As described above, when the apparent specific gravity of the support is reduced, the sedimentation speed of the support is reduced. The sedimentation speed of the carrier is 3 cm / s
In the following cases, the carrier may not be able to be separated by gravity. If the specific gravity of the carrier is increased to prevent such a problem, the carrier accumulates on the bottom of the biological reaction tank.

Further, an underwater stirrer is arranged at the bottom of the biological reaction tank, and the water in the biological reaction tank is stirred with the carrier by the underwater stirrer. It has been found that the shearing action of the stream makes it difficult for the rodent to attach. Therefore,
In this way, attachment of the micro-animal to the carrier can be prevented. However, it is difficult to uniformly stir the carrier to every corner of the biological reaction tank, and there is a problem that the efficiency of treating wastewater by microorganisms carried on the carrier decreases.

The present invention is intended to solve such a problem, and an object of the present invention is to eliminate the possibility that micro-animals adhere to a carrier on which microorganisms are carried, and efficiently discharge wastewater flowing into a biological reaction tank. An object of the present invention is to provide a wastewater treatment system capable of treating wastewater.

[0013]

The wastewater treatment system of the present invention has an inlet for raw water and an outlet for treated water, and a large number of carriers carrying microorganisms flow into the biological reaction tank. A wastewater treatment system in which raw water is treated by microorganisms carried on the carrier while floating in the raw water,
An underwater stirrer that is arranged on the bottom surface of the biological reaction tank and flows the water in the biological reaction tank along with the carrier along the bottom surface of the biological reaction tank, and water that flows along the bottom surface of the biological reaction tank. An ascending flow path arranged vertically in the biological reaction tank so as to flow together with the carrier, and water in the ascending flow path such that water in the ascending flow path flows upward together with the carrier. Aeration means for aerating the water, and a treated water channel provided in the biological reaction tank such that the carrier is gravity separated from the water aerated by the aeration means, and the water from which the carrier has been separated flows. It is characterized by having.

The carrier has a particle diameter of 0.5 to 5.0 m.
m and a specific gravity of about 1.03 to 1.15.

The carrier is formed of a hydrogel with an organic polymer material containing a powder of an inorganic material, and the microorganisms are entrapped and fixed.

The above-mentioned carrier is accommodated in the biological reaction tank in an amount of about 5 to 20% by volume based on the water in the biological reaction tank.

The biological reaction tank has a water depth of 7 to 15 m.

The ascending flow path is constituted by a partition wall which is vertically arranged at an appropriate distance from the bottom surface of the biological reaction tank, and side surfaces of the biological reaction tank.

The raw water inflow discharges the raw water from the side surface of the biological reaction tank into the ascending flow passage.

An underwater stirrer disposed on the bottom of the biological reaction tank is disposed below the treated water channel.

A treated water channel is provided inside the biological reaction tank so that water from which the carrier is separated flows, and the outflow channel allows water overflowing from the treated water channel to flow. It has become.

The aeration means sucks water in the ascending channel above the ascending channel, mixes it with compressed air, and discharges it to the surroundings.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing an example of an embodiment of the wastewater treatment system of the present invention. In this wastewater treatment system, in the biological reaction tank 11 into which raw water flows,
Raw water is treated by the microorganisms carried on the carrier. The biological reactor 11 has a width of 10 m.
On the other hand, the depth is about 100 m, and the depth is about 10 m. The bottom surface 11a of the biological reaction tank 11 is inclined so as to be gradually deeper along the width direction from one side surface 11b to the other side surface 11c.

The biological reaction tank 11 is provided with a raw water inflow pipe 12 into which raw water flows. The raw water inflow pipe 12 is piped outside the side surface 11c of the biological reaction tank 11, and has a main pipe 12a connected to a vertically intermediate portion of the side surface 11c, and a branch from the main pipe 12a.
And a branch pipe 12b connected to the bottom surface 11a. The main pipe 12a supplies the raw water to the biological reaction tank 11 by a raw water pump 12d. The raw water discharged from the raw water pump 12d to the main pipe 12a includes:
Air is mixed by the air supply pipe 15c of the aeration device 15. The air mixed with the raw water in the main pipe 12a is ejected into the biological reaction tank 11 as fine bubbles. Since the bubbles are fine, the residence time in water is long, and the oxygen dissolving efficiency is enhanced. Raw water supplied by a raw water pump 12e is supplied to the branch pipe 12b to the bottom of the biological reaction tank 11 via an on-off valve 12e.

The inside of the biological reaction tank 11 accommodates a large number of microscopic carriers 13 carrying nitrifying bacteria as microorganisms that oxidize ammonia nitrogen contained in raw water to nitrite or nitric acid. The carrier is made of an organic polymer material containing a powder of an inorganic material, and has a particle diameter of 0.5 to 5.0.
It is composed of a hydrogel having a size of about mm and a specific gravity of about 1.03 to 1.15, and the microorganisms are comprehensively fixed. The carrier 13 is 5 to 5% of water treated in the biological reaction tank 11.
It is mixed in water in the biological reaction tank 11 at a rate of about 20% by volume. The support 13 on which the microorganisms are supported floats in the raw water flowing into the biological reaction tank 11 from the raw water inflow pipe 12, and oxidizes ammonia nitrogen in the raw water by the microorganisms supported by the support 13. .

An underwater stirrer 14 is provided on the bottom surface 11a of the biological reaction tank 11. This underwater stirrer 14 is arranged close to the shallow side edge of the bottom surface 11a,
The water in the biological reaction tank 11 is sucked from above and discharged obliquely downward. The water discharged from the underwater agitator 14 is supplied to the bottom surface 11 of the biological reaction tank 11.
It flows along a.

Inside the biological reaction tank 11, a partition wall 11 is formed along the longitudinal direction so that an ascending flow path 11e is formed along a side surface 11c which is continuous with the deepened side edge of the bottom surface 11a.
d is provided. The lower end of the partition 11d is spaced from the bottom 11a by an appropriate distance. Partition wall 11
d is the side surface 11c up to the middle of the side surface 11c in the vertical direction.
It is in a vertical state with a certain interval from c,
The upper part of the partition wall 11d is sequentially arranged on the side surface 11
It is inclined away from c. Therefore, the rising channel 1
The upper portion of 1e is in a state of gradually expanding toward the upper side. The upper end of the partition wall 11d is located at an appropriate distance below the level of water contained in the biological reaction tank 11.

The side surface 11c of the biological reaction tank 11 adjacent to the partition 11d is higher than the other side surface 11b.
Also, the other side surface 11 which is lower than the side surface 11c
An outflow channel 11f into which overflow water from the side surface 11c flows is provided on the upper outer surface of the upper portion b. Overflow water from inside the biological reaction tank 11 is drained through the outflow channel 11f.

In the biological reaction tank 11, a separation wall 26 is provided near the side surface 11b provided with the outflow water channel 11f. The separation wall 26 is vertically arranged at an appropriate distance from the side surface 11b, and the lower end thereof is located in the middle of the biological reaction tank 11. Separation wall 26 and side 11
b, a treated water channel 25 is formed. The underwater stirrer 14 is disposed below the treated water channel 25.

The raw water flowing into the biological reaction tank 11 from the raw water inflow pipe 12 flows along with the carrier 13 along the bottom surface 11a of the biological reaction tank 11 by the underwater stirrer 14,
Ascending flow path 11e passing between partition wall 11d and bottom surface 11a
And flows into the ascending channel 11e by the aerated air.
Rises inside. The water that has risen in the ascending flow path 11e passes above the partition wall 11d together with the carrier 13, flows to the upper part of the biological reaction tank 11, and circulates and flows in the biological reaction tank 11. Treated water channel 25 between separation wall 26 and side surface 11b
In this case, the treated water rises at a rising speed lower than the sedimentation speed of the carrier 13, and the carrier 13 is separated by gravity from the water and sediments.

The raw water that has flowed into the biological reaction tank 11 through the raw water inflow pipe 12 is housed in the biological reaction tank 11, and a number of fine carriers 13 float in the raw water. The raw water in the biological reaction tank 11 together with the carrier 13
Raw water flowing along the bottom surface 11a by the underwater stirrer 14 provided on the bottom surface 11a and flowing into the ascending flow channel 11e by raw water discharged from the main pipe 12a of the raw water inflow pipe 12 together with aeration air. Rises inside. At this time, the water that rises in the ascending flow path 11e together with the carrier 13 is aerated by the aerated air blown into the raw water. The aerated water flows from the ascending flow path 11e to the upper part of the biological reaction tank 11 together with the carrier 13, and circulates in the biological reaction tank 11.

As described above, in the water flowing in the biological reaction tank 11, ammonia nitrogen is oxidized to nitrous acid or nitric acid by nitrifying bacteria, which are microorganisms carried on the carrier 13 floating in the water. . In addition, the activated sludge floating in the wastewater reduces the biological demand oxygen (BOD). In particular, since the water in the biological reaction tank 11 is aerated by the aeration air blown by each air supply pipe 15c of the aeration apparatus 15, the nitrifying bacteria and activated sludge supported on the support 13 are subjected to aerobic conditions. The wastewater is treated efficiently at.

The specific gravity of the carrier 13 flowing with the wastewater in the biological reaction tank 11 is 1.03 to 1.15, which is slightly larger than the specific gravity of water.
Without flowing into the inside, the gravity separation from the treated water
No. 3 sinks in water. And the settled support 13
Flows with water by the underwater stirrer 14. The treated water separated by the carrier 13 overflows the lowered side surface 11b of the biological treatment tank 11, and the effluent channel 1
It is discharged within 1f.

In such a wastewater treatment system, the amount of air supplied to the wastewater can be freely changed by the aeration device 15, so that an appropriate amount of aeration can be controlled according to the quality and amount of the raw water. . In addition, because the dissolved oxygen amount of the treated water is too large, the dissolved oxygen is separated as bubbles in the sedimentation pond in the subsequent process,
There is no danger that sedimentation of suspended solids is suppressed.

FIG. 2 is a perspective view showing another example of the embodiment of the wastewater treatment system of the present invention. In this wastewater treatment system, each side surface 11b and 11b is placed in a biological reaction tank 11 in which a large number of carriers carrying microorganisms are accommodated.
The partition walls 11d are provided vertically along the entire length of the biological reaction tank 11 so that the ascending flow paths 11e are respectively formed along c. In the middle of the up-flow channel 11e in the up-down direction, the diffuser 17 of the aeration device
Each is provided horizontally along the longitudinal direction. Each of the diffuser pipes 17 has a plurality of branch pipe sections 1 horizontally protruding to each side.
7a are provided at equal intervals in the longitudinal direction, and each branch pipe portion 17a is formed in a tubular shape by, for example, a porous material, and compressed air is supplied to the inside thereof, whereby The aeration air is discharged toward it.

A pair of separating walls 11g, which are vertically arranged along the longitudinal direction, are provided at appropriate intervals between the partition walls 11d, which are central portions in the width direction of the biological reaction tank 11. . The lower end of each separation wall 26 is
Are formed in the middle of the vertical direction, and an overflow weir along the longitudinal direction is formed on the upper end surface of each separation wall 26. Between each separation wall 26, a treated water channel 25 in which treated water treated by microorganisms carried on the carrier rises.
Are formed. Partition wall 1 above each separation wall 26
On the 1d side, an outflow water channel 11f is provided along the longitudinal direction. Each outflow channel 11f is provided with each separation wall 2
The treated water flowing into the outflow channel 6 is discharged to the outside of the biological reaction tank 11.

An underwater stirrer 14 is provided at the center of the bottom surface 11a of the biological reaction tank 11. The underwater stirrer 14 discharges the water sucked from the upper part to the surroundings from the lower part.

In such a wastewater treatment system, when raw water flows into the biological reaction tank 11 from a raw water inflow pipe (not shown), the raw water is stirred by the underwater stirrer 14 together with the carrier on which the microorganisms are supported, and the biological water is stirred. It flows into the rising channel 11e provided on each side in the reaction tank 11.
The drainage that has flowed into each ascending channel 11e is aerated and flows upward by compressed air that is discharged upward from each diffuser pipe 17 of the aerator. The aerated drainage flows between the partition wall 11e and the separation wall 26 together with the carrier, and the carrier is separated by gravity at that portion, and the carrier sediments. The water separated by the sedimentation of the carrier flows into the treated water channel 25 between the separation walls 26, overflows from the upper end surfaces of the respective separation walls 26, and is discharged into the outflow water channel 11f.

FIG. 3 is a cross sectional view showing still another example of the embodiment of the wastewater treatment system of the present invention. In this wastewater treatment system, a separation tank 18 is provided above a biological reaction tank 11 in which a carrier 13 supporting microorganisms is accommodated. The separation tank 18 has a rectangular cylindrical shape with an open upper end surface and a lower end surface, and corrugated unevenness is provided on the upper end surface of each separation wall 18a arranged along the width direction. I have. Each separation wall 18a in the separation tank 18
A horizontal processing water channel 18b is provided on the upper outer surface of each of the processing water channels 18b.
Each of them is connected to a drain pipe 19 that penetrates the upper part of the biological reaction tank 11 in the width direction through each of the c.

The underwater stirrer 1 is placed at the center of the bottom surface 11a below the center of the separation tank 18 in the biological reaction tank 11.
4 are provided. The underwater stirrer 14 discharges water sucked from the upper part obliquely downward to the periphery. The upper suction port has a cover 30.
Is provided, and when the underwater agitator 14 is stopped,
The carrier that sediments in the biological reaction tank 11 is prevented from flowing into the stirrer and accumulating. Thereby, the carrier that has flowed into and accumulated in the underwater stirrer 14 prevents an extreme load from being applied to the motor of the underwater stirrer 14 at the start of operation, and prevents the motor from being destroyed. Breakage of the carrier can also be prevented.

Draft pipes 22 that constitute ascending flow channels are provided vertically on each side of the biological reaction tank 11 in the width direction. Each draft tube 22 is disposed with a lower end surface thereof being appropriately spaced from the bottom surface 11 a of the biological reaction tank 11. The upper end surface of each draft tube 22 is located slightly above the vertical center of the biological reaction tank 11.

An aeration and stirring device 21 is connected to the upper end surface of each draft tube 22. Each aeration and stirring device 2
1 sucks water downward and discharges the water obliquely downward from above. Each aeration and stirring device 2
1 is connected to an air supply pipe 21a piped into the biological reaction tank 11 from above the biological reaction tank 11, and aeration air supplied by the air supply pipe 21a is sucked into the aeration stirring device 21. Mixed in water.

In the wastewater treatment system having such a configuration,
The raw water flowing into the biological reaction tank 11 is mixed with the carrier on which the microorganisms are loaded by the underwater stirrer 14 provided at the center of the bottom surface 11a of the biological reaction tank 11.
It is diffused to the periphery along the bottom surface 11a. The wastewater diffused to the surroundings together with the carrier is supplied to the aeration and stirring device 2 on each draft pipe 22 arranged at a predetermined position in the biological reaction tank 11.
1, by suction from the lower end surface of each draft 22 into each draft tube 22 together with the carrier,
The compressed air supplied from the air supply pipe 21a is mixed by the aeration and stirring device 21, and is discharged obliquely downward to the periphery while being aerated.

As described above, while the water is circulating in the biological reaction tank 11, the ammonia nitrogen in the wastewater is oxidized to nitrite or nitric acid by the nitrifying bacteria and the activated sludge, which are microorganisms carried on the carrier. During the treatment, the BOD is oxidatively decomposed.

The carrier contained in the water discharged from the aeration and stirring device 21 has a specific gravity of 1.03 to 1.03 which is slightly larger than the specific gravity of the water.
Due to its specific gravity of 1.15, it is gravity separated below the separation tank 18 and slowly sinks in water. Then, the settled carrier is diffused around by the underwater stirrer 14 arranged at the center of the bottom surface 11a, and is sucked into the ascending flow path in the draft pipe 22 by the aeration stirrer 21 as described above. In a state of rising and being aerated, it is circulated below the separation tank 18.

The water discharged below the separation tank 18 is treated by microorganisms and activated sludge carried on the carrier, and the carrier is separated by gravity in a state where the carrier is separated by gravity.
And overflows from each of the separation walls 18a in the separation tank 18, and the treated water channel 18b and the branch pipe portion 18c
Through the drain pipe 19.

In such a wastewater treatment system as well, since the amount of air supplied to the wastewater can be freely changed by each aeration / stirring device 21, the amount of dissolved oxygen in the treated water is too large, so In the sedimentation basin, there is no possibility that dissolved oxygen is separated as bubbles and sedimentation of suspended solids is suppressed.

In the above-described embodiment, the carrier is used in which the microorganisms are entrapped and fixed. However, a carrier in which the microorganisms are bound may be used.

[0050]

As described above, the wastewater treatment system according to the present invention provides an underwater stirrer disposed on the bottom surface of the biological reaction tank when the wastewater in the biological reaction tank is treated by the carrier carrying the microorganisms. Thereby, the drainage flows along the bottom surface together with the carrier, flows into the ascending flow path, is aerated and raised in the ascending flow path, and then separated by gravity separation. Therefore, the carrier can be agitated over the whole of the deep-type biological reaction tank, and there is no possibility that the small animals adhere to the carrier and the carrier cannot be separated by gravity. In addition, the wastewater can be stably treated for a long period of time by the microorganisms carried on the carrier without the risk of the carrier being deposited at the corner of the biological reaction tank. Since a screen such as a mesh screen is not used by utilizing the difference in specific gravity for separating the carrier and water, work such as elimination of clogging of the screen is not required, and maintenance is easy.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an embodiment of a wastewater treatment system of the present invention.

FIG. 2 is a partially cutaway perspective view showing another embodiment of the wastewater treatment system according to the present invention.

FIG. 3 is a sectional view of a main part showing still another example of the embodiment of the wastewater treatment system of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Biological reaction tank 11a Bottom surface 11b Side surface 11c Side surface 11d Partition wall 11e Upflow path 11f Outflow water channel 12 Raw water inflow pipe 12a Main pipe 12b Branch pipe 13 Carrier 14 Underwater stirrer 15 Aeration device 15c Air supply pipe 17 Aeration pipe 18 Separation tank 21 Aeration Stirrer 22 Draft tube 25 Treated water channel 26 Separation wall

Claims (10)

[Claims] Claims: 1. A method according to claim 1, wherein a plurality of carriers carrying microorganisms are suspended in the raw water flowing into the biological reaction tank. A wastewater treatment system in which raw water is treated by supported microorganisms, the wastewater treatment system being disposed on a bottom surface of a biological reaction tank, and causing water in the biological reaction tank to flow along with the support along the bottom surface of the biological reaction tank. An underwater stirrer, an ascending flow path arranged vertically in the biological reaction tank so that water flowing along the bottom surface of the biological reaction tank flows in with the carrier, and water in the ascending flow path. Aeration means for aerating the water in the ascending flow path so that the water flows upward together with the carrier, and the carrier separated by gravity from the water aerated by the aeration means, and the water separated from the carrier flows in A treated water channel provided in the biological reaction tank so that Wastewater treatment system characterized by comprising. 2. The carrier has a particle diameter of 0.5 to 5.0.
The wastewater treatment system according to claim 1, wherein the specific gravity is about 1.03 to 1.15. 3. The support body is formed of a hydrogel with an organic polymer material containing a powder of an inorganic material,
The wastewater treatment system according to claim 1, wherein the microorganisms are comprehensively fixed. 4. The wastewater treatment system according to claim 1, wherein the carrier contains about 5 to 20% by volume of water in the biological reaction tank in the biological reaction tank. 5. The wastewater treatment system according to claim 1, wherein the water depth of the biological reaction tank is 7 to 15 m. 6. The bioreactor according to claim 1, wherein the ascending flow path is constituted by a partition wall which is vertically arranged at an appropriate distance from a bottom surface of the biological reaction vessel, and a side face of the biological reaction vessel. Wastewater treatment system. 7. The wastewater treatment system according to claim 1, wherein the raw water inflow discharges the raw water from a side surface of the biological reaction tank toward an inside of the ascending flow path. 8. The wastewater treatment system according to claim 1, wherein an underwater stirrer disposed on a bottom surface of the biological reaction tank is disposed below the treated water channel. 9. A treated water channel is provided inside the biological reaction tank so that water from which the carrier is separated flows, and the outflow channel receives water overflowing from the treated water channel. The wastewater treatment system according to claim 1, wherein the wastewater treatment system is adapted to perform the treatment. 10. The aeration means according to claim 1, wherein the water in the ascending flow path is suctioned above the ascending flow path, mixed with compressed air, and discharged to the surroundings. Wastewater treatment system.