JPH1177075A - Fluidized bed type waste water treating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently perform biotreatment by performing efficiently fluidization of a biomembrane-sticked carrier. SOLUTION: The bottom part of a treating tank 13 having a raw water inlet part 11 at the lower part and a treated water outlet part 12 at the upper part is made into a funnel shape and the raw water is discharged toward the funnel-shaped bottom part. A wedge wire screen 14 for separating a carrier is provided at the treated water outlet part 12 and an agitation vane 18 for controlling the amt. of living bodies deposited on the carrier C is provided in the treating tank 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized-bed wastewater treatment apparatus, and more particularly, to a fluidized-bed wastewater treatment apparatus for treating wastewater by a fluidized bed using a biofilm-adhered carrier.

[0002]

2. Description of the Related Art A wastewater treatment method using a fluidized bed has a large amount of living organisms and a high agitation power. It is possible to perform processing. For this reason, many studies have been conducted in the past, but there are examples of practical application in small-scale facilities in industrial wastewater treatment, but few practical examples in relatively large scale such as public sewage treatment.

FIG. 8 shows a fluidized bed using a conventional biofilm-adhered carrier, and shows an example of a fluidized bed for performing aerobic treatment. The fluidized bed 1 has a raw water inflow section 3 provided at the bottom of the treatment tank 2 and a treated water outflow section 4 provided at the top of the tank.
And a support layer 5 and a diffuser 6 provided at the lower part of the tank, and a separation tube 7 for preventing carrier outflow provided in the large-diameter portion 2a at the upper part of the tank. The biofilm-adhered carrier C introduced into the treatment tank 2 is supplied from the raw water inflow section 3 to the treated water outflow section 4.
Fluidized by the water flow rising toward the, the water purification treatment by biological reaction.

In the conventional fluidized bed as described above, a silica sand having a specific gravity of about 1.4 to 2.7 and a diameter of about 0.4 to 1 mm is used as a biofilm-adhering carrier (hereinafter simply referred to as a carrier). , Granular activated carbon, anthracite and the like are used. When using such a carrier having a relatively large specific gravity,
Considering the power for fluidization, the diameter is 0.5m
m or smaller, it is necessary to use a flow rate required for fluidization of 500 to 800 m
/ Day, which was relatively high, and did not always match the reaction rate. For example, if the effective height of the fluidized bed is 3
When the reaction time is about m, the reaction time becomes about 2 to 5 minutes. Therefore, it is necessary to take measures such as performing a circulation treatment or performing a multi-stage treatment. Further, since the carrier having a large specific gravity is fluidized only by the rising flow rate of the raw water flowing into the tank, it is difficult to scale up and it is difficult to adapt to a sewage treatment plant having a large treatment scale.

[0005] In addition, if a carrier having a fine size is used, it is difficult to separate the carrier from the suspended biofilm or suspended components in the influent water. Therefore, adaptation to wastewater containing much impurities such as sewage is difficult. This is difficult, and particularly in the case of a device that supports a carrier using a support layer, there is a possibility that the support layer may be blocked.

In addition, even when the same carrier is used and the flow rate is constant, the fluidization rate (expansion rate) of the carrier is greatly affected by the water temperature and the amount of organisms adhering to the carrier, and the fluidization rate is too low. In such a case, the treatment efficiency is reduced. If the treatment efficiency is too high, the carrier may flow out together with the treated water. In particular, in the case of a fluidized bed operated at a high load, the biofilm is liable to enlarge, and the optimum flow rate range is greatly changed. For example, it is reduced to 1/3 to 1/10 compared to before the organism is attached. It can be.

Therefore, in the conventional fluidized bed, it is necessary to provide a sufficient height above the processing tank in order to prevent the carrier from flowing out even if the fluidization rate becomes high to some extent. In addition, it was necessary to provide a large-scale separation device for separating the treated water and the carrier. Especially,
In the aerobic treatment, it is necessary to separate gas such as diffused air, so that the upper water area has to be increased. For this reason, the conventional fluidized-bed wastewater treatment apparatus has a disadvantage that its installation area is large.

Accordingly, an object of the present invention is to provide a fluidized-bed wastewater treatment apparatus capable of efficiently fluidizing a carrier and performing efficient biological treatment.

[0009]

In order to achieve the above object, a fluidized bed type wastewater treatment apparatus according to the present invention is provided in a treatment tank having a raw water inflow portion at a lower portion of a tank and a treated water outflow portion at an upper portion of the tank. In a fluidized-bed wastewater treatment apparatus that performs treatment of sewage wastewater by charging a biofilm-adhered carrier, the bottom of the treatment tank is formed in a funnel shape in which an upper part is expanded, and the raw water inflow part is provided in the treatment tank. It is characterized in that it is arranged so as to discharge raw water toward the bottom.

Further, in the fluidized bed type wastewater treatment apparatus of the present invention, the biofilm-adhered carrier has a specific gravity of 0.9 to 1.2 and a size of 3 to 20 mm. A screen for separating treated water and a biofilm-adhering carrier flowing out of the treated water outflow section is provided, a stirring means is provided in the treatment tank, and a treated water outflow section is provided above the treatment tank. A screen that separates treated water and biofilm-attached carriers flowing out from the screen is installed in a ring shape, and a carrier that removes the biofilm-attached carriers captured by the screen is rotated by a rotation shaft arranged at the center of the ring-shaped screen. In addition to providing the removing means, the rotating shaft is provided with a stirring means for stirring the water to be treated in the treatment tank. When the stirring means is provided, the expansion coefficient of the biofilm-adhered carrier is detected. Provide means Together, by the detected expansion providing a control means for controlling the operation of said stirring means, further, to the water inlet, is characterized in that it comprises a backflow preventing means of the raw water.

[0011]

1 to 4 show an embodiment of a fluidized-bed wastewater treatment apparatus according to the present invention. FIG. 1 is a schematic diagram of a fluidized-bed wastewater treatment apparatus, and FIG. FIG. 3 is a plan view, FIG. 3 is a longitudinal sectional view of a main part, and FIG. 4 is a longitudinal sectional view showing an example of a backflow prevention means provided in a raw water inflow section.

The fluidized bed type wastewater treatment apparatus shown in this embodiment is
It is composed of a bottomed rectangular cylindrical treatment tank 13 having a raw water inflow portion 11 at a lower portion and a treated water outflow portion 12 at an upper portion, respectively.
The bottom of the processing tank 13 is formed in a funnel shape (hopper shape) in which the lower part converges and the upper part expands. Raw water inlet 1
1 is disposed so as to discharge raw water toward a lower end converging portion of the funnel-shaped bottom portion.
A ring-shaped carrier separating wedge wire screen 14 is provided.

Further, a rotating shaft 16 driven by a motor 15 is provided on a central axis of the processing tank 13, and the carrier C captured by the wedge wire screen 14 is removed by the rotating shaft 16. And a stirring blade 18 as stirring means for stirring the inside of the processing tank 13 and controlling the amount of organisms adhering to the carrier C.

The wedge wire screen 14 is shown in FIG.
As shown in the figure, a large number of wedge-shaped wires 14a formed in a ring shape are held at predetermined intervals by a plurality of support rods 14b located on the outer peripheral side thereof. After flowing between the wires 14a and flowing onto the partition plate 12a, the water flows out of the treated water outflow portion 12. By appropriately setting the distance between the wedge-shaped wires 14a, the wedge wire screen 14 can efficiently discharge treated water and sludge while suppressing clogging, and can reliably prevent the carrier C from flowing out. it can.

The scraper 17 attached to the rotating shaft 16 via the support arm 17a rotates along the inner periphery of the wedge wire screen 14, and is disposed between the scraper 17 and the inner peripheral surface of the wedge wire screen 14. Is provided with an appropriate interval according to the size of the carrier C. By operating the scraper 17 continuously or intermittently, it is possible to reliably prevent the wedge wire screen 14 from being clogged by the carrier C. .

Further, at the end (raw water discharge end) of the raw water inflow section 11, a backflow preventing means as shown in FIG. 4 is provided. This backflow prevention means has a raw water inlet 1
9a and a cylindrical body 19 having a valve seat 19b.
And a float valve 20 housed vertically below the valve seat 19b of the cylindrical body 19 and a diffuser 21 provided so as to cover the outer periphery of the lower half of the cylindrical body 19. A plurality of outlets 19 c for discharging raw water into the diffuser 21 are provided in the middle part of the diffuser 21.

When the raw water is flowing, as shown in FIG. 4, the inflow energy of the raw water causes the float valve 20 to move downward away from the valve seat 19b.
The diffuser 2 passes from the inside of the cylindrical body 19 through the ejection port 19c.
1 and is guided by the diffuser 21 and discharged to the bottom of the tank. Therefore, by appropriately setting the position and size of the spout 19c and the shape (spread angle, etc.) of the diffuser 21, the raw water can be placed at an arbitrary position on the bottom of the tank.
Discharge can be performed at an arbitrary flow rate, and ascending flow over the entire processing tank 13 can be formed as shown by an arrow A in FIG. 1 depending on the shape of the tank bottom. Thereby, the carrier C
Can be effectively fluidized, and an efficient biological reaction can be performed. In addition, since there is no need to provide a support layer in which clogging may occur as in the related art, it is possible to easily treat wastewater containing a large amount of impurities such as sewage.

On the other hand, when the inflow of raw water stops, the float valve 20 rises due to buoyancy and presses against the valve seat 19b as shown by the imaginary line in FIG.
The water inside does not flow back to the raw water inflow portion 11. By using such a backflow prevention means using the float valve 20, backflow can be prevented with a simpler structure than a normal valve body (check valve), and clogging due to impurities in the flowing raw water is also eliminated. Moreover, the inflowing raw water can be effectively dispersed.

The carrier C put into the treatment tank 13 is made of plastics, for example, polypropylene (specific gravity of about 0.9) or polyethylene (specific gravity of about 0.92), inorganic substances such as silica or calcium for specific gravity adjustment, metals, etc. A plastic carrier to which a powder is added, the specific gravity of which can be arbitrarily adjusted by adjusting the amount of silica or the like, is used. The shape of the carrier C is arbitrary as long as it can be molded, such as a sphere or a pipe. However, the surface is preferably rough and has fine irregularities to which a biofilm can easily adhere. Furthermore, 50-300μ suitable for the inhabitation of microorganisms
Those having about m holes are particularly preferred.

The specific gravity and size of the carrier C are determined by the shape of the fluidized bed,
The optimum range can be set according to the configuration and processing conditions, but the specific gravity is in the range of 0.9 to 1.2, and the size is 3 to 2
It is preferable to set the range to 0 mm. If the specific gravity is too small, even if the inside of the tank is agitated by the stirring means, most of it floats near the water surface, so that it does not function sufficiently as a biofilm-adhered carrier.
However, there is a disadvantage that it is difficult to obtain a sufficient residence time in the fluidized bed because the flow rate must be increased in order to fluidize the fluid. That is, the residence time in the fluidized bed is set in consideration of the processing time required for the biological reaction, and thereby the processing speed (upflow velocity) is determined. What is necessary is just to set a specific gravity. Further, the size (size) of the carrier can be arbitrarily selected according to the specific gravity, the surface area, and the like.
m. Further, such a plastic carrier also has an advantage that loss due to abrasion is small as compared with the above-described anthracite, granular activated carbon, and the like.

Therefore, since it is possible to use the carrier C having a specific gravity and a size corresponding to the amount of the inflowing raw water, it is possible to set the holding amount of the organism and the stirring power in an optimum state.
Processing efficiency can be greatly improved. Further, a relatively large carrier C is used, and the treated water outlet 12
By separating the carrier by providing a wedge wire screen 14, it is not necessary to increase the water area at the top of the tank or to provide a means for separating gas due to aeration as in the conventional case. Can be achieved.

If the size of the carrier is less than 3 mm, the size of the wedge wire screen 14 must be reduced, which increases the manufacturing cost of the wedge wire screen itself and increases the possibility of clogging. . Conversely, if the size of the support exceeds 20 mm, the specific surface area (effective area) of the support will decrease, which will adversely affect the processing efficiency. As described above, by using the carrier C having an appropriate size and physically separating the carrier C using the wedge wire screen 14, the carrier C is prevented from flowing out due to a flow rate fluctuation or the like, and a stable process is continued. can do.

The agitating blade 18 separates the biofilm adhered to the carrier C by the water flow energy by stirring the inside of the processing tank 13 and the mechanical energy of the agitating blade 18 itself. Is controlled to an optimal state.

That is, in a fluidized bed, generally,
At the start of operation when the biofilm is not attached to the carrier C, 20 to 20
The water flow rate is set so as to have a fluidization rate of about 30%, but the fluidization rate increases as a biofilm is formed. For efficient processing, the fluidization rate should be 100
It is necessary to maintain it at about 200%.

The energy required for fluidizing the carrier C is 5
The fluidization rate increases as the flow rate increases up to a fluidization rate of about 0%, but thereafter remains substantially constant, and the fluidization rate depends on the amount of biofilm attached to the carrier C. That is,
At a fluidization rate of 100 to 200%, the fluidization energy depending on the flow velocity is constant, and the input energy per unit volume of the fluidized bed decreases in inverse proportion to the fluidization rate. Therefore, the raw water inflow section 1
It is difficult to control the amount of biofilm attached only by the stirring force associated with the flow rate of the raw water flowing from 1, and the fluidization rate cannot be maintained within a predetermined range. And, as the biofilm grows, the fluidization rate further increases, and eventually
The carrier C flows out together with the treated water.

As described above, the carrier C rises to the upper part of the processing tank 13 as the amount of biofilm attached increases, so that the stirring wings 18 are placed at an appropriate position in the processing tank 13.
By providing mechanical agitation by providing a biofilm, the biofilm adhered to the carrier C can be appropriately peeled off, and the carrier C from which the biofilm has been peeled loses buoyancy and the sedimentation velocity increases, thereby increasing the fluidized bed. It will return to the lower part. In particular, by installing the stirring blade 18 in the upper layer of the fluidized bed, only the enlarged biofilm in the upper layer can be efficiently separated. At this time, even if an excessive agitation force is applied to remove the biofilm too much, only the biofilm that has risen to the upper layer will not significantly change the biological retention amount of the entire device, and will affect the treated water quality. There is almost no. In addition, since it is not necessary to perform the conventional cleaning of the carrier, continuous operation is possible,
Processing efficiency can be further improved.

Therefore, by appropriately setting the operation time and the stirring power (the number of revolutions, the shape of the blades, etc.) of the stirring blade 18, it is possible to control the amount of the biofilm adhering to the carrier C. Inside, the most effective fluidization rate (expansion rate)
For example, the fluidization rate is always 100
High-efficiency processing can be performed while maintaining the range of ~ 200%. Further, by providing a means for detecting the expansion rate of the carrier, such as a sludge interface meter, and measuring the fluidized state in the tank, and by providing a control means for controlling the operating state of the stirring blade 18 based on the detected expansion rate. In addition, more effective driving can be automatically performed.

Further, by controlling the amount of the biofilm adhering to the carrier C to an appropriate range, the carrier C hardly rises to the treated water outflow portion 12, so that the water area at the upper part of the tank is reduced as in the related art. It is not necessary to increase the size or to provide a means for separating gas accompanying the air diffusion, so that the apparatus can be simplified and downsized.

The treatment tank 13 may have a cylindrical shape, and when aerobic treatment is performed by the above-described fluidized-bed wastewater treatment apparatus, a diffuser may be provided at an appropriate position at the bottom of the tank. further,
The wedge wire screen 14 can be partially provided on the wedge wire screen, for example, on a part of a partition wall having an appropriate height. Instead of the rotary scraper 17, other carrier removing means, for example, empty washing or reverse washing can be used. If washing is used, it can be formed into an arbitrary shape. Further, a general screen may be used.

Further, the agitating blades 18 may be provided over the entire upper and lower portions of the fluidized bed to agitate the entire fluidized bed. In this case, the shape and the number of the upper and lower stirring blades, the spacing between the upper and lower stirring blades, and the like can be changed. The shape of the stirring blade can be a paddle type as shown in FIG. Any shape can be used as long as it can remove the enlarged biofilm. In addition, a circulation pump or the like can be used as the stirring means other than the stirring blade.

Furthermore, if the stirring means such as the stirring blade 18 can surely prevent the carrier C from excessively rising, the wedge wire screen 14 for separating the carrier can be omitted. Conversely, when the amount of biofilm attached is controlled to an appropriate range by washing the carrier C by aeration or the like, the stirring means may be omitted.

As shown in the schematic diagram of FIG. 5, when the volume (bottom area) of the treatment tank 13 is large, the bottom is divided into a plurality of funnel-shaped portions 13a, and raw water is added to each funnel-shaped portion 13a. Each of the inflow portions 11a can be provided. As a result, scale-up can be easily performed, and the system can be adapted to a large-scale sewage treatment plant.
Similarly, the wedge wire screen 14 and the stirring blade 18 of the treated water outflow portion 12 can be divided into a plurality of parts. The same components as those in the embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description is omitted.

FIG. 6 shows an example of a wastewater treatment facility using the fluidized bed wastewater treatment apparatus of the present invention. The treatment tank 13 having the structure shown in FIG. 1 is replaced with a denitrification tank (anaerobic treatment tank). ), A floating type nitrification tank 31 and a final sedimentation tank 32 are provided at the subsequent stage, and nitrogen treatment is performed in addition to BOD and SS treatment.

The inflow sewage (raw water) is returned through the path 33 after returning to the nitrification liquid from the floating type nitrification tank 31 and returned through the path 33 after pretreatment such as settling treatment in the first settling tank. The sludge is mixed with the returned sludge from the final sedimentation basin 32 and flows into the bottom of the treatment tank 13 from the raw water inflow section 11.
The raw water flowing into the treatment tank 13 is subjected to an anaerobic purification treatment, mainly a denitrification treatment by a biofilm (microorganism) attached to the carrier C, and then flows into the floating nitrification tank 31 from the treated water outlet 12. In the floating type nitrification tank 31, a carrier in which nitrifying bacteria are comprehensively immobilized is charged, and an air diffuser 35 provided at the bottom of the tank is provided.
Aerobic purification treatment, mainly a nitrification reaction, is performed by the aeration from the nitrogen, and nitrification of nitrogen in raw water is performed.

Nitrified water (nitrification liquid) from the floating type nitrification tank 31 flows out of a path 37 through a carrier separation screen 36, and a part thereof (100 to 300% of the raw water amount) is pumped by a pump 38, It is returned to the treatment tank 13 via the path 33, and the remainder flows into the final sedimentation basin 32. The treated water from which the sludge has been separated in the final sedimentation basin 32 is discharged from a path 39 to a river or the like via a treated water tank or the like. A part of the sludge generated in the final sedimentation basin 32 is returned to the pump 40 and the route 34 as returned sludge.
The remaining part is sent to the sludge storage tank by the pump 41 and the path 42 as surplus sludge and processed there.

When the nitrifying liquid is returned to the treatment tank 13 as described above, even if the flow rate of the raw water decreases due to fluctuations in the flow rate of the inflowing sewage or the flow of the raw water stops, the carrier C is maintained at the flow rate of the nitrifying liquid alone. Is preferably made fluidizable.

FIG. 7 shows another example of the construction of wastewater treatment equipment using the fluidized-bed wastewater treatment apparatus of the present invention.
A treatment tank 13 having the structure shown in FIG. 1 is used as a denitrification tank (anaerobic treatment tank) in the same manner as described above, and a non-chemical injection pressurized flotation device 51 and an aerobic filter bed 52 are provided at the subsequent stage. It is.

The raw water mixes with the nitrification liquid from the aerobic filter bed 52 returned via the channel 53 and flows into the bottom of the treatment tank 13 from the raw water inflow section 11, and becomes anaerobic due to the biofilm attached to the carrier C. Purification treatment (mainly denitrification reaction) is performed.

The anaerobic treated water (anaerobic treated water)
After mixing with the pressurized air dissolving water supplied from the treatment tank 13 through the treated water outflow portion 12 through the passage 54, the mixture flows into the pressurized flotation device 51. In the pressurized flotation separation device 51, suspended components in the anaerobic treated water are attached to microbubbles generated from the pressurized air-dissolved water to reduce the apparent specific gravity, thereby causing them to float. Floss)
Is scraped by the scraper 55 and sent to the sludge storage tank from the path 56. Sludge settled at the bottom is also sent to the sludge storage tank. The sludge concentration at this time is 3 to 5%, which is higher than gravity concentration in a conventional sludge concentration tank.

A part of the water subjected to the solid-liquid separation treatment by the pressurized flotation device 51 (pressurized flotation water) is withdrawn from the outlet 57 through the passage 57 and mixed with the compressed air. Is supplied to the anaerobic treated water from the passage 54 and mixed. The remaining part of the pressurized flotation treatment water flows into the aerobic filter bed 52 from the path 58.

The aerobic filter bed 52 has a contact material filling section 59 at the top of the tank for holding aerobic microorganisms, a filter material filling section 60 at the bottom of the tank filled with the filter medium, and a diffuser 61 at the bottom of the tank. The pressurized levitation treated water flowing into the aerobic filter bed 52 is
The aerobic purification processing (mainly nitrification reaction) and the filtration processing are performed by passing through the contact material filling section 59 and the filter medium filling section 60 which are maintained in an aerobic state by the air diffuser 61. Flows out to the treated water outflow path 62 at the bottom of the tank. A part of the treated water passes through the pump 63 and the path 53 and is returned to the treatment tank 13 as a nitrification liquid. The remaining portion of the treated water is discharged from the route 64 to a river or the like via a treated water tank or the like.

Since the pressure flotation device 51 has a higher removal rate of suspended components as compared with the ordinary sedimentation treatment, the inflow load to the aerobic filter bed 52 at the subsequent stage can be reduced, and the volume of the device can be reduced. It becomes possible to do. In the floating treatment, components that easily float, such as hair, oil, and scum, can be almost completely removed, so that the clogging of the aerobic filter bed 52 and the occurrence of scum are reduced.

Therefore, by combining the fluidized-bed type wastewater treatment apparatus of the present invention with the chemical-free injection pressurized flotation apparatus, the treatment efficiency of the wastewater treatment equipment can be greatly improved, and the equipment can be miniaturized. Can be planned. Further, the washing wastewater from the aerobic filter bed 52 is returned to the raw water, mixed, and subjected to pressurized flotation treatment again, thereby making it possible to unify the sludge generation location and increase the concentration thereof, thereby reducing the amount of sludge generation. However, in a relatively small sewage treatment facility that greatly affects running costs, the running costs can be significantly reduced.

[0044]

As described above, according to the fluidized-bed wastewater treatment apparatus of the present invention, the carrier can be effectively fluidized by the ascending flow of the inflowing raw water, and efficient biological treatment can be performed. Can be. In particular, by using a carrier having a relatively small specific gravity and a relatively large size, treatment efficiency in a fluidized bed can be improved, and separation of treated water and a carrier can be easily performed. Furthermore, by installing a wedge wire screen at the treated water outlet, the carrier can be reliably separated. Further, by providing a stirring means to control the amount of organisms attached to the carrier, wastewater treatment can be performed at the most effective fluidization rate.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one embodiment of a fluidized-bed wastewater treatment apparatus according to the present invention.

FIG. 2 is a schematic plan view similarly.

FIG. 3 is a longitudinal sectional view of a main part.

FIG. 4 is a longitudinal sectional view showing an example of a backflow prevention means provided in a raw water inflow portion.

FIG. 5 is a schematic view showing another embodiment of a fluidized bed type wastewater treatment apparatus.

FIG. 6 is a system diagram showing an example of a wastewater treatment facility using the fluidized-bed wastewater treatment apparatus of the present invention.

FIG. 7 is a system diagram showing another configuration example of the wastewater treatment facility.

FIG. 8 is a schematic view showing an example of a conventional fluidized bed type wastewater treatment apparatus.

[Explanation of symbols]

Reference numeral 11: raw water inlet, 12: treated water outlet, 13: treatment tank, 14: wedge wire screen, 15: motor, 16: rotating shaft, 17: scraper, 18: stirring blade,
19 ... cylindrical body, 19b ... valve seat, 20 ... float valve, 21 ...
Diffuser, 31: Floating nitrification tank, 32: Final sedimentation basin, 51: Pressurized flotation separator, 52: Aerobic filter bed

Claims (7)

[Claims] 1. A fluidized bed wastewater treatment apparatus for treating a wastewater by charging a biofilm-adhering carrier into a treatment tank having a raw water inflow part at a lower part of a tank and a treated water outflow part at an upper part of the tank. A fluidized bed type wastewater treatment, wherein the bottom of the treatment tank is formed in a funnel shape with an open top, and the raw water inflow portion is arranged to discharge raw water toward the bottom of the treatment tank. apparatus. 2. The biofilm-adhered carrier has a specific gravity of 0.9 to 2.0.
The fluidized-bed wastewater treatment apparatus according to claim 1, wherein the size is 1.2 to 3 mm. 3. A fluidized bed type wastewater treatment apparatus according to claim 1, wherein a screen for separating treated water flowing out from a treated water outflow portion and a biofilm-adhered carrier is provided above the treatment tank. . 4. The fluidized-bed wastewater treatment apparatus according to claim 1, wherein a stirring means is provided in the treatment tank. 5. A screen for separating treated water flowing out of a treated water outlet from a biofilm-attached carrier is provided in a ring shape on an upper portion of the treatment tank, and a rotating shaft arranged at the center of the ring-shaped screen is provided. 2. A carrier removing means for removing a biofilm-adhered carrier which has been captured by a screen while being rotated, and a stirring means for stirring water to be treated in a treatment tank is provided on the rotating shaft. Fluid bed wastewater treatment equipment. 6. The apparatus according to claim 4, further comprising means for detecting the expansion rate of the biofilm-adhered carrier, and control means for controlling the operation of the stirring means based on the detected expansion rate. Fluid bed wastewater treatment equipment. 7. The fluidized-bed wastewater treatment apparatus according to claim 1, wherein the raw water inflow section includes a backflow preventing means for the raw water.