JPH07108292A - Fluidized bed carrier and method for accelerating precipitation thereof, and carrier recovery method - Google Patents

Abstract

PURPOSE:To maintain high speed treatment performance and to achieve miniaturization by a method wherein a fluidized bed carrier is constituted from a magnetically reactive material which is magnetically attracted by exciting action and magnetically released by demagnetizing action. CONSTITUTION:The interior of a reaction tank R is partitioned by means of an intermediate partition wall 1 to form a reaction tank 2 using anaerobic bacteria on the front inflow side and a reaction tank 3 using aerobic bacteria on the rear outflow side. A proper amount of carriers X having magnetic reactivity are put into both of the reaction tanks 2, 3. The carriers X are made of synthetic resin, as base material, such as polypropylene, and iron powder is mixed into the base material, which is formed into granules so that the granules are magnetically attracted by exciting action and magnetically released by demagnetizing action. Water treated in the tank 3 is sent together with the carriers X from an outflow pipe 12 to a settling tank 13. In the tank 13, an electromagnet 15 is energized to magnetically attract the carriers X to which bacteria have been attached, thereby precipitating them to the bottom of the tank 13, following which electricity is cut off to demagnetize the electromagnet 15 to release the carriers X to lift them through an air lift tube 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed carrier having magnetic reactivity, which is useful for a fluidized bed biofilm treatment, a method for promoting precipitation of the same, and a method for recovering the carrier.

[0002]

2. Description of the Related Art Conventionally, in a fluidized bed biofilm treatment, carrier materials such as sand, anthracite (anthracite), activated carbon, porous ceramics, plastics, sponges and glass spheres have been adopted as a microorganism attachment medium. By fluidizing this in a reaction tank called a reactor, the surface area of the carrier on which microorganisms adhere is dramatically increased, and the biofilm treatment by a large amount of microorganisms can be accelerated. On the other hand, the speeding up of such biological treatment can contribute to the demand for downsizing and compaction of the treatment equipment, and recently, the demand for practical application of the fluidized bed biofilm treatment device is extremely strong. However, with the fluidization of the carrier put into the reaction tank, and as the biological treatment of the wastewater in the tank due to the growth of microorganisms attached to the carrier progresses,
Or, if affected by the inflow of new treated wastewater,
The fluidized bed carrier to which the microorganisms adhere is mixed with the treated water and flows out of the reaction tank, which then flows out of the system.
Therefore, conventionally, an overflow weir called a triangular weir is provided in the upper part of the reaction tank, or a net or screen for preventing carrier outflow is provided immediately before the treated water discharge port of the reaction tank,
As shown in FIG. 2 which shows a conventional example of Japanese Patent Publication No. 2-5153, Japanese Patent Publication No. 1-59037.
As disclosed in Japanese Patent Publication No. JP-A No. 2003-242242, a diagonal partition plate with a lower opening is provided, or the porous partition wall disclosed in Japanese Patent Publication No. 2-5153 is tilted in the middle part of the tank, or
As disclosed in FIG. 1 of Japanese Patent Publication No. 2-5154, a slanted passage is inclined by a partition wall and a baffle plate whose lower end is opened in the middle portion of the tank, and as shown in FIG. As described above, the partition walls and the many baffle plates form a large number of inclined passages to prevent the fluidized bed carrier to which the microorganisms adhere from flowing out of the tank.

[0003]

However, in the case of the outflow prevention measures such as those mentioned above, the fluidized bed carrier which is about to flow out causes a clogging phenomenon of the screen or the porous partition wall. Make daily maintenance as a practical device troublesome. In addition, in the case of the above-mentioned other preventive measures or the overflow structure, the outflow of the fluidized bed carrier cannot be prevented even if the clogging does not occur. From this,
The carrier adhering to the microorganisms flowing out of the reaction tank is allowed to flow into the precipitation tank in the subsequent step, and after it is precipitated and separated for a relatively long period of time, the supernatant liquid is sterilized and drained,
It is indispensable to send the sediment to the sludge thickening storage tank and return the desorbed liquid to the previous process to collect the thickened sludge with a vacuum car for post-treatment, or to settle the sludge thickening tank to the sludge thickening tank. After being sent to the sludge, the sludge is concentrated over a relatively long time, the desorbed liquid is returned to the previous process, and the concentrated sludge is sent to the sludge storage tank, which is then collected by a vacuum truck for post-treatment. I have no choice. However,
The above-mentioned concentrated sludge still contains a mixture of carriers, which leads to an increase in the amount of sludge to be carried out and, in addition, a new fluidized bed carrier which is commensurate with a considerable amount of the carriers lost from the reaction tank. Replenishment is essential. In addition, since the sedimentation tank and sludge thickening tank described above have a treatment structure that causes sedimentation by natural sedimentation or gravity sedimentation, a considerable amount of treatment time is required for sedimentation separation in a stationary state (when no coagulant is used). Need. Also, since the fluid bed carrier itself has a small difference in specific gravity from the treated water and tends to float in the tank, it takes a lot of time for its gravity settling, and as a result, this type of settling tank and sludge concentration The tanks cannot be made compact and compact, and the advantage of speeding up the fluidized bed biofilm treatment cannot be utilized.

[0004]

Therefore, in the present invention, in order to solve the above-mentioned problems in the fluidized bed biofilm treatment, a fluidized bed carrier having magnetic reactivity, that is,
A fluidized bed carrier composed of a magnetically responsive material that is magnetically attracted by the exciting action of the electromagnet and released by the demagnetizing action of the electromagnet, more specifically, a synthetic resin group such as polypropylene, polyethylene, or polyvinyl chloride. Of a fluidized bed carrier by providing a method for treating a fluidized bed biofilm using a base material, which is mixed with iron powder for granulation or a pelletized carrier is newly developed. To prevent spills to the river and promote precipitation, or
This is to cope with the promotion of the precipitation treatment on the carrier during the solid-liquid separation and the improvement of the carrier recovery efficiency.

[0005]

When a fluidized bed carrier is subjected to a precipitation treatment in a settling tank, or a carrier and a sludge component are subjected to solid-liquid separation in a carrier separation tank, and a carrier floating in the tank is subjected to a precipitation treatment or recovery, these precipitates are precipitated. By energizing an electromagnet provided in a tank or carrier separation tank and exciting the electromagnet, the floating carrier is magnetically attracted, and the carrier magnetically precipitates in a relatively short time, or a magnetic belt provided inside or outside the tank. The carrier is recovered by magnetically adsorbing onto the substrate.

[0006]

EXAMPLES First, as a carrier material in the present invention, a mixture of a synthetic resin base material such as polypropylene, polyethylene, or polyvinyl chloride, and iron powder as a magnetic substance having magnetic reactivity is used. 100 resin base material
The iron powder is mixed in an amount of 15 to 50 g per g, and the mixture is melted and then formed into a linear shape or a rod shape by an extrusion molding machine or an extrusion molding machine, and then shredded after passing through a cooling tank. By forming into pellets with
A flat-shaped pellet-shaped carrier X having a length of about 3 to 6 mm, a width of about 3 mm, and a thickness of about 2 mm is obtained. Of course, instead of this, the carrier X may be granulated to form a granular material having a diameter of about 2 to 5 mm. When the mixing ratio of iron powder is about 15 to 50 g relative to 100 g of the synthetic resin base material, the specific gravity of the carrier is 1.03 to
It can be about 1.50, and has both appropriate fluidity and sedimentability as the carrier X used for the fluidized bed biofilm treatment. Hereinafter, as a first application example of a fluidized bed biofilm treatment apparatus, in which the carrier X having magnetic reactivity according to the present invention is suitable, an anaerobic method combining anaerobic treatment and aerobic treatment shown in FIGS. 1 and 3 is used. A case of the aerobic fluidized bed type will be described as a second application example, a case of the aerobic fluidized bed type shown in FIG. 4 will be described, and a case of the batch type fluidized bed type shown in FIG. 5 will be described as a third application example. .

[0007]

[First application example] First, in FIG. 1 showing an outline of the entire apparatus of a fluidized bed biofilm treatment apparatus, R is a reaction tank partitioned by an intermediate partition wall 1, and the front inflow side thereof is formed by anaerobic microorganisms. It is divided into a reaction tank 2 (hereinafter referred to as an anaerobic reaction tank), and the rear outflow side is a reaction tank 3 for aerobic microorganisms (hereinafter,
The anaerobic reaction tank 2 and the aerobic reaction tank 3 are charged with an appropriate amount of the carrier X having magnetic reactivity according to the present invention. Reference numeral 4 is a sewage inflow pipe into the anaerobic reaction tank 2, 5 is an inflow passage for guiding the inflow water downward, and 6 is an agitation device provided in the anaerobic reaction tank 2 for agitating the in-tank wastewater and the carrier X. The carrier X is fluidized by mixing, and the anaerobic treatment of the in-tank wastewater by the anaerobic microorganisms attached to the fluidized carrier X and growing is repeated. Reference numeral 7 is an advection passage for the anaerobic treated water, 8 is an admission port for the anaerobic treated water provided in the upper part of the intermediate partition wall 1, and receives the new inflow of the sewage from the sewage inflow officer 4, and anaerobics the advection passage 7. The treated water is allowed to flow through the advection port 8 and sent to the next aerobic reaction tank 3. Reference numeral 9 is an air diffuser installed at the bottom of the aerobic reaction tank 3, and the carrier X is agitated and mixed with the waste water in the tank and the carrier X in an aerated state by the air sent from the blower B provided outside the tank. Is aerated, and the aerobic treatment of the in-tank wastewater with aerobic microorganisms that grow by adhering to the fluidized carrier X is repeated. Reference numeral 10 denotes a pumping pump provided in the aerobic reaction tank 3, which pumps up aerobic treated water aerated in the aerobic reaction tank 3, that is, an appropriate amount of nitrification liquid,
It is returned to the inflow side of the anaerobic reaction tank 2 through the circulation return pipe 11, and this is agitated and mixed with the in-tank wastewater of the anaerobic reaction tank 2, whereby denitrification treatment is performed on the in-tank wastewater. Instead of the pump 10, the nitrification solution may be pumped and returned by an air lift pump device including an air lift pipe and an air pipe (not shown) shown in FIG. Reference numeral 12 denotes an outflow pipe for the aerobic treated water treated in the aerobic reaction tank 3, which receives the inflow of the anaerobic treated water from the advection port 8 and sends the aerobic treated water to the next settling tank 13. The treated water at this stage is sent out in a state where SS suspended by the aeration treatment in the aerobic reaction tank 3 and the carrier X in which aerobic microorganisms adhere and float are mixed. Reference numeral 14 denotes a center well provided at the center of the settling tank 13 for guiding the inflowing aerobic treated water downward. Reference numeral 15 denotes an electromagnet provided at the bottom of the settling tank 13 (or the lower outer peripheral portion including the bottom may be used), which is excited by energization to cause the center well 1
Carrier X with aerobic microorganisms flowing down 4 attached,
By curling the lower end opening of the center well 14 and magnetically attracting the carrier X which is going to gently float upward again or the carrier X which floats in the tank, the microorganisms are attracted to the bottom of the precipitation tank 13. The attached carrier X is magnetically precipitated in a relatively short time. Reference numeral 16 is an air lift pipe provided in the settling tank 13, the lower end of which is formed at the bottom of the settling tank 13,
The sediment at the bottom of the tank is pumped up by the air sent from an air pipe (not shown). This air lift pipe 1
An air lift pump device is configured by 6 and the air pipe. Therefore, by cutting off the power supply to the electromagnet 15, the electromagnet 1
When the air is supplied to the air lift pipe 16 after demagnetizing 5 and releasing the magnetic force to the precipitated carrier X, the precipitate containing the carrier X precipitated at the bottom of the tank is pumped up by the air lift action and the advection pipe 17 Is sent to the next carrier separation tank 18. Reference numeral 19 denotes an overflow weir provided at the upper end of the settling tank 13, which prevents the floating scum from flowing out and allows the supernatant of the settling tank 13 to flow to the next disinfection tank 21 through the advection pipe 20. The water is discharged from the discharge pipe 22 to the outside. Reference numeral 23 denotes an air diffuser provided in the carrier separation tank 18, which receives the supply of air from the blower B and repeats the aeration process for the in-tank wastewater containing the carrier X, whereby the adherents are separated from the carrier X. Solid-liquid separation. Reference numeral 24 is an electromagnet provided at the bottom of the carrier separation tank 18, and when excited, magnetically attracts the carrier X during the aeration process to cause magnetic precipitation in a relatively short time. Two
Reference numeral 5 denotes an air lift pipe provided in the carrier separation tank 18, the lower end of which is opened at the bottom of the carrier separation tank 18 and a precipitate containing the precipitated carrier X is fed from an air pipe (not shown). The air is lifted by the air lift action. Therefore, when the air is supplied to the air lift pipe 25 after releasing the magnetic force to the precipitated carrier X by cutting off the power supply to the electromagnet 24, the carrier X precipitated at the bottom of the tank is pumped up by the air lift action, By returning it to the inflow side of the anaerobic reaction tank 2 through the carrier return pipe 26, it is reused as the fluidized bed carrier X in the anaerobic biological treatment. Further, the suspension containing the separated sludge that has been subjected to solid-liquid separation in the carrier separation tank 18 is discharged from the advection pipe 27 to the next sludge storage tank 28, and then pumped up to the vacuum vehicle and carried out. Therefore, if a material having magnetic reactivity is used as the carrier X in the fluidized bed biofilm treatment, the precipitation treatment can be performed in a relatively short time, and the carrier X also flows out of the system. It can be prevented, and it will be excellent in the collection and reuse.

[0008]

[Modification 1] Carrier separation tank 18 in the first application example
In the case of, the case was explained in which the carrier X solid-liquid separated by the air diffuser 23 was magnetically precipitated, and the carrier X was pumped up and collected by the air lift pump device composed of the air lift pipe 25 and the air pipe. Alternatively, as shown in FIG. 2, a magnetic belt 29 may be rotatably suspended and supported between the inside and the outside of the carrier separation tank 18. In this case, when the magnetic belt 29 is excited and rotated, the carrier X solid-liquid separated in the tank is magnetically attracted to the magnetic belt 29 and is carried out of the tank. Scraper it 30
The carrier X is recovered by scraping off with.

[0009]

[Modification 2] In the first application example, the anaerobic reaction tank 2 and the aerobic reaction tank 3 are formed by partitioning the reaction tank R with the intermediate partition wall 1.
As shown in FIG. 3, the anaerobic reaction tank 2 is provided on the wastewater inflow side, and the aerobic reaction tank 3 is provided on the treated water drainage side, and both tanks are connected by the advection pipe 31. It is also possible to add the appropriate amount of the carrier X of the present invention to both tanks, and then subject it to the fluidized bed biofilm treatment. In FIG. 3, reference numeral 32 is an air lift pipe for pumping up the nitrification liquid which is the treated water in the aerobic reaction tank 3, and this and an air pipe (not shown) constitute an air lift pump device. In the anaerobic tank of the anaerobic reaction tank 2, the sewage in the tank is fluidized by the carrier X to which aerobic microorganisms are adhered and an appropriate amount of nitrification liquid purified by aeration treatment is circulated back to the inflow side of the anaerobic reaction tank 2. It is used for denitrification by mixing with sewage. The other configurations and processing methods other than the above are the same as those in the case of the first application example, and therefore, the same reference numerals are given and the description thereof is omitted.

[0010]

[Second application example] In the case of the aerobic fluidized bed type biofilm treatment device shown in FIG. 4, when the anaerobic reaction tank 2 in the anaerobic aerobic fluidized bed type biofilm treatment device of FIGS. That is, the wastewater that has flowed into the aerobic reaction tank 3 from the inflow pipe 4 is subjected to aeration treatment by the air diffuser 9, so that the carrier X of the present invention charged into the tank is adhered to the carrier X while being fluidized. A biofilm is grown by aerobic microorganisms, and aerial treatment of sewage in the tank is performed. When fresh sewage flows in, the treated water in the upper layer of the aerobic reaction tank 3 is sent out from the outflow pipe 12 and sent to the center well 14 of the next settling tank 13. Carrier X with attached microorganisms flowing down the center well 14.
Is magnetically attracted by excitation of the electromagnet 15 provided at the bottom of the settling tank 13 to promote settling, whereby the carrier X or the carrier X to which microorganisms are attached is magnetically precipitated in a relatively short time. Also, the supernatant liquid is the overflow weir 19 at the upper part of the settling tank 13.
Spilled, disinfected and discharged to the outside. Then, the carrier X settled on the bottom of the settling tank 4 is pumped up by an air lift pump device composed of an air lift pipe 16 and an air pipe (not shown) at the stage of demagnetizing the electromagnet 15 to release the magnetic force, and separately. The settled sludge is sent to a solid-liquid separation facility for processing (for small-scale tanks with a relatively small processing capacity). Alternatively, as shown in the above-described first application example and its first modification, the settled sludge containing the carrier X is pumped up and sent to the next carrier separation tank 18, the carrier is separated, and then to the inflow side of the aerobic reaction tank 3. The carrier X is returned or the carrier X is recovered by the magnetic belt 29 as shown in FIG.

[0011]

[Third Application Example] Next, as a third application example, a case of a batch type fluidized bed type biofilm treatment apparatus shown in FIG. 5 will be described. Reference numeral 33 denotes a batch reaction tank, which is a series of batch processing in which sewage water in the tank is anaerobically stirred and aerobically stirred, followed by precipitation treatment, discharge of the supernatant liquid, and discharge of excess sludge. Reference numeral 34 denotes a pumping pump provided in a flow rate adjusting tank (not shown) in the previous step, which starts its operation after receiving a series of batch processing in the batch type reaction tank 33, and as shown in FIG. , New sewage is flown into the batch reaction tank 33 from the inflow pipe 4, and as shown in FIGS. The operation of the pump 33 is stopped at the high level H level. With this, the carrier X having magnetic reactivity
Is fluidized in the tank, and anaerobic treatment is performed by the anaerobic microorganisms attached to it. Next, by operating the air diffuser 9 as shown in FIG. 6C, the tank wastewater is agitated while being aerated, and aerobic treatment of the tank wastewater by the aerobic microorganisms attached to the carrier X is performed. . 35 is a batch reaction tank 33
An electromagnet provided at the bottom of the batch reaction tank 33, which is excited by energization and magnetically attracts the fluidized-bed carrier X floating in the tank, as shown in FIG. 7 (d). Carrier X with microorganisms attached to it or carrier X from which it has been peeled
Magnetically precipitate in a relatively short time. Reference numeral 36 denotes a scum outflow prevention cone that is bulged above the treated water outflow side,
The outflow pipe 12 is provided in the lower position. Reference numeral 37 denotes a drainage pump provided in the outflow pipe 12, and as shown in FIG. 7 (e), the supernatant liquid of the upper tank portion is discharged from the lower portion of the scum outflow prevention cone 36 to float on the surface layer portion. While preventing the outflow of scum, the treated water whose tank water level is in the range up to the low level L is quickly drawn out, and the next disinfection tank 2
It is sent to No. 1 and then released. Even when the supernatant liquid is discharged, the excited state of the electromagnet 35 is maintained,
The magnetic precipitate is rolled up so that it is not discharged. Denoted at 38 is a pump for pumping excess sludge containing the carrier X. After demagnetizing the electromagnet 35 to release the magnetic force to the precipitate, the excess sludge is pumped up to operate, and the advection pipe 17
To the next carrier separation tank 18. In the carrier separation tank 18, as shown in the case of the first application example, the inside of the tank is aerated by the air diffuser 23, and the electromagnet 24 is excited. With this, the carrier X and sludge containing microorganisms are stripped, the stripped sludge is discharged to the next sludge storage tank 28, and the electromagnet 24 is demagnetized to release the magnetic force to the carrier X.
The batch reaction tank 33 is operated by operating an air lift pump device including an air lift pipe 25 and an air pipe (not shown).
The carrier X is returned to the inflow side or the carrier X is magnetically attracted to the magnetic belt 29 for recovery as shown in the modification of FIG. In FIGS. 6 and 7, 39 is a screen for inflowing dirty water, which removes foreign substances mixed in the dirty water pumped up from a flow rate adjusting tank (not shown).

[0012]

INDUSTRIAL APPLICABILITY As described above, the present invention provides a fluidized bed carrier having magnetic reactivity as a carrier for treating a fluidized bed biofilm,
That is, a fluidized bed carrier composed of a magnetically responsive material that is magnetically attracted by the exciting action of the electromagnet and released by the demagnetizing action of the electromagnet, more specifically, a synthetic resin such as polypropylene, polyethylene, or polyvinyl chloride. Based on a permeable base material and mixed with iron powder for granulation,
By newly developing a pelletized fluidized bed carrier and providing a fluidized bed biofilm treatment method using the same, it is possible to significantly accelerate the precipitation treatment of the fluidized bed carrier.
It is also excellent in preventing the carrier from flowing out of the system. Therefore, in order to take advantage of the speedup of fluidized bed biofilm treatment, for example, depending on the downsizing of the reaction tank, the precipitation tank, carrier separation tank, etc. can be handled with a small and compact capacity. It can greatly contribute to the practical application of the biofilm treatment device.

[Brief description of drawings]

FIG. 1 is an overall schematic view of an anaerobic aerobic fluidized bed biofilm treatment apparatus.

FIG. 2 is a diagram showing a modified example of a carrier separation tank.

FIG. 3 is a view showing a modified example in which an anaerobic reaction tank and an aerobic reaction tank are independent.

FIG. 4 is a schematic diagram of an aerobic fluidized bed biofilm treatment device.

FIG. 5 is an overall schematic view of a batch type fluidized bed biofilm treatment apparatus.

6A and 6B are diagrams showing the first half of a batch treatment process, wherein FIG. 6A shows a sewage inflow process, FIG. 6B shows an anaerobic stirring process, and FIG. 6C shows an aerobic stirring process.

FIG. 7 is a diagram showing the latter half of the batch treatment process, wherein FIG. 7 (d) shows the magnetic precipitation process, FIG. 7 (e) shows the supernatant liquid discharging process, and FIG. 7 (f) shows the sludge transfer process.

[Explanation of symbols]

 X carrier R Reaction tank 2 Anaerobic reaction tank 3 Aerobic reaction tank 6 Stirrer 9, 23 Air diffuser 10, 34, 38 Pumping pump 13 Precipitation tank 14 Center well 15, 24, 35 Electromagnet 16, 25, 32 Air lift tube 18 Carrier separation tank 19 Overflow weir 21 Disinfection tank 26 Carrier return pipe 28 Sludge storage tank 29 Magnetic belt 30 Scrubber 33 batch reaction tank 36 Scum outflow prevention cone 37 Drainage pump

Claims (14)

[Claims] 1. A fluidized bed carrier, wherein the carrier has magnetic reactivity. 2. A fluidized bed carrier characterized in that the carrier is made of a magnetically reactive material that is magnetically attracted by an exciting action and released by a demagnetizing action. 3. The fluidized bed carrier according to claim 1, wherein the carrier is a mixture of a synthetic resin base material and a magnetic material. 4. The carrier according to claim 1, wherein the carrier is based on a synthetic resin base material such as polypropylene, polyethylene, or polyvinyl chloride, and iron powder is mixed with the base material for granulation or pelletization. The fluidized bed carrier according to claim 2 or 3. 5. The carrier according to claim 1, wherein the ratio of iron powder is 15 to 50 g and the specific gravity is 1.03 to 1.50 per 100 g of the synthetic resin base material. The fluidized bed carrier according to claim 3 or 4. 6. The carrier has a structure in which a mixture of a synthetic resin base material and iron powder is melted, formed into a linear or rod-like shape, cooled, and then shredded into pellets. The fluidized bed carrier according to claim 1, claim 2, claim 3, claim 4 or claim 5. 7. A fluidized bed biofilm treatment method in which a carrier charged in a reaction tank is fluidized, and wastewater in the tank is treated with a biofilm by microorganisms attached to the carrier, wherein the fluidized bed carrier has magnetic reactivity. A method for promoting the precipitation of a fluidized bed carrier, wherein the carrier is magnetically attracted by exciting an electromagnet. 8. The fluidized bed carrier is composed of a synthetic resin base material such as polypropylene, polyethylene, or polyvinyl chloride, and iron powder is mixed with the base material for granulation or pelletization. The method for accelerating the precipitation of a fluidized bed carrier as described in 1. 9. The fluidized bed carrier comprises a synthetic resin base material 100.
The method for promoting precipitation of a fluidized bed carrier according to claim 7 or 8, wherein the iron powder is mixed in an amount of 15 to 50 g with respect to g, and the specific gravity thereof is set to 1.03 to 1.50. 10. The method according to claim 7, wherein an electromagnet provided in a precipitation tank, a carrier separation tank, a reaction tank, or the like is excited to flow in the tank or magnetically attract a floating bed carrier. Item 10. A method for promoting precipitation of a fluidized bed carrier according to Item 9. 11. A carrier charged in a reaction vessel is fluidized,
In a fluidized bed biofilm treatment method for treating biofilm in a tank with microorganisms attached to a carrier, the fluidized bed carrier is provided with magnetic reactivity, and an electromagnet provided in a precipitation tank, a carrier separation tank or a reaction tank is used. By exciting, it will flow in the tank,
The floating fluidized bed carrier is magnetically attracted to perform precipitation treatment, and the magnetically precipitated fluidized bed carrier or the precipitate containing the fluidized bed carrier is pumped up by a pump device after demagnetizing the electromagnet to release the magnetic force. A method for recovering a carrier. 12. The carrier recovery method according to claim 11, wherein the fluidized bed carrier magnetically precipitated in the carrier separation tank is pumped up by an air lift pump device and returned to the reaction tank. 13. A carrier charged in a reaction vessel is fluidized,
In a fluidized bed biofilm treatment method for treating biofilm in a tank with microorganisms attached to a carrier, the fluidized bed carrier has magnetic reactivity, and an electromagnet provided in a carrier separation tank or a reaction tank is excited. The fluidized bed carrier that flows in the tank or is suspended by magnetic force is subjected to precipitation treatment, and the magnetically precipitated fluidized bed carrier or the precipitate containing the fluidized bed carrier is demagnetized by demagnetizing the electromagnet to release the magnetic force. A method for recovering a carrier, characterized in that the device is configured to return the carrier to a pumping reaction tank. 14. A carrier separation tank is so constructed that it is solid-liquid separated and flows in the tank, or a floating fluidized bed carrier is magnetically attracted to a magnetic belt facing the carrier separation tank to be collected. A method for recovering a carrier, comprising: