JP3412328B2 - Sewage treatment equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewage treatment device, and more particularly to a sewage treatment device for purifying low-pollution sewage.

[0002]

2. Description of the Related Art A sewage treatment apparatus provided with a plate-shaped rotating disk to which microorganisms are attached is provided in a reaction tank into which sewage flows in, when the organic load of sewage is relatively low, or the load fluctuation is relatively large. Used in some cases. The reason for this is that microorganisms are attached to the surface of the rotating disk, so that the microbial layer that corresponds to the substrate and load in the wastewater grows, and when the load increases, the microbial layer becomes too thick and peels off. This is because the quality of treated water is deteriorated. In this type of conventional sewage treatment equipment, when nitrifying and denitrifying nitrogenous ammonia in sewage to remove it, in order to effectively work nitrifying bacteria that are aerobic bacteria and denitrifying bacteria that are anaerobic bacteria Both an aerobic tank and an anaerobic tank were provided, and a rotating disk was arranged in each tank.

In addition, the applicant of the present invention provided a rotating disk submerged by about half in the dirty water in the reaction tank to which microorganisms adhered, and a submerged rotating flat membrane below the rotating disk to rotate the disk. A sewage treatment device has been proposed in which microorganisms attached to a disk perform oxidation treatment of organic matter in wastewater and nitrification treatment of ammonia nitrogen, and filter solid components in wastewater with a rotary flat membrane (JP-A-2- No. 52096).

[0004]

However, the conventional sewage treatment apparatus provided with the rotating disk to which the microorganisms are attached has the following problems.
Since two reaction tanks, an aerobic tank and an anaerobic tank, are required, there is a drawback that the apparatus becomes large. Further, the sewage treatment apparatus proposed by the applicant of the present application does not perform denitrification treatment even if nitrification treatment can be performed in the removal of nitrogen components, so that nitric acid nitrogen components remain in the treated water to remove nitrogen. There is a drawback that you cannot do it. Therefore, it is necessary to provide a denitrification tank at the latter stage of the sewage treatment apparatus, and eventually the apparatus becomes large.

The present invention has been made in view of the above circumstances, and is an oxidation treatment of an organic substance in wastewater which requires an aerobic condition and a nitrification treatment of an ammonia nitrogen component in the same reaction tank, and an anaerobic condition. An object of the present invention is to provide a sewage treatment apparatus that can efficiently perform both denitrification treatment of necessary nitrate nitrogen components.

[0006]

In order to achieve the above object, the present invention is provided with a reaction tank into which sewage flows and a submerged sewage water in the reaction tank, which is formed into a hollow body with a porous membrane. A carrier member formed by attaching microorganisms to the outer surface thereof to form a microbial layer composed of two layers, an outer layer of aerobic microorganisms and an inner layer of anaerobic microorganisms, and the anaerobic microorganisms in the hollow body of the carrier member. A substrate supply device for supplying a substrate solution that is a nutrient of, and an aeration device for supplying air to the waste water in the reaction tank, and an organic substance in the waste water in the outer layer of the microbial layer formed on the supporting member. And the nitrification treatment of the ammonia nitrogen component, and the denitrification treatment of the nitrate nitrogen component in the inner layer of the microorganism layer.

Further, in order to achieve the above object, the present invention provides
A reaction tank into which sewage flows, and is fixed so as to face a communication port formed at a predetermined interval in the axial direction of the rotary shaft for a hollow carrying member rotatably arranged in the reaction tank,
Part of it is provided so as to be exposed on the surface of the sewage, and the outer surface of the hollow disk formed of a porous membrane attaches microorganisms to the outer layer of aerobic microorganisms and the inner layer of anaerobic microorganisms. Two
A plurality of supporting members forming a microbial layer consisting of a plurality of layers, and a substrate supply for supplying a substrate solution, which is a nutrient of the anaerobic microorganism, into the hollow discs of the plurality of supporting members via the rotating shaft for the supporting members An apparatus, and, while rotating the supporting member, while performing the oxidation treatment of the organic matter in the wastewater and the nitrification treatment of the ammoniacal nitrogen component in the outer layer of the microorganism layer formed on the supporting member, the microorganism layer The inner layer is characterized by performing denitrification treatment of nitrate nitrogen components.

[0008]

According to the present invention, the outer layer portion of the microbial layer adhering to the supporting member becomes the aerobic zone, the inner layer portion becomes the anaerobic zone, and aerobic microorganisms in the aerobic zone and anaerobic zone in the anaerobic zone. Natural microbial formation, and when the concentration of ammonia nitrogen in the wastewater is low, nitrification process proceeds in the aerobic zone at a rate controlled by ammonia nitrogen,
After that, it was experimentally confirmed that the denitrification process proceeds in the presence of nutrients in the anaerobic zone, and it was made based on this result.

That is, according to the invention of claim 1, the aerobic microbial layer formed on the carrying member and the anaerobic microbial are used.
Among the microbial layers of the layer, in order to supply the substrate solution that is a nutrient source to the anaerobic microbial layer formed in the inner layer, the supporting member is formed into a hollow body with a porous membrane and is formed in the hollow body. It was configured so that the substrate solution could be supplied from the substrate supply device. As a result, the aerobic microbial layer is in an aerobic state due to the supply of air from the aerator, and efficiently oxidizes organic substances in wastewater and nitrifies ammoniacal nitrogen components. On the other hand, since the substrate solution supplied into the hollow body of the supporting member permeates the membrane and is supplied to the anaerobic microbial layer in the anaerobic state, denitrification treatment can be efficiently performed in the anaerobic microbial layer.

Therefore, in the same reaction vessel, both the oxidation treatment of an organic substance which requires an aerobic condition and the nitrification treatment of an ammonia nitrogen component and the denitrification treatment of a nitrate nitrogen component which requires an anaerobic condition are efficiently performed. You can do it well. Further, claim 3
According to the invention, the plurality of supporting members are fixed so as to face the communication holes formed in the rotating shaft for the supporting members, and a part of the supporting members is exposed on the wastewater surface. As a result, the rotating supporting member alternately performs exposure to the atmosphere and submersion in dirty water, and when exposed to the atmosphere, oxygen is supplied to the aerobic microorganisms attached to the supporting member. It is possible to omit the aeration device that supplies air into the waste water in the reaction tank.

Further, in addition to the structure of claim 1 or claim 3, since the filtration membrane is provided in the reaction tank, the solid component in the waste water can be removed in the same reaction tank.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of a wastewater treatment apparatus according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is an explanatory diagram for explaining a first embodiment of a wastewater treatment device according to the present invention. As shown in FIG. 1, the sewage treatment apparatus 10 is mainly provided with an inflow pipe 14 for sewage 12 such as sewage, a reaction tank 16 into which the sewage 12 flows, a submerged arrangement in the sewage 12 in the reaction tank 16, and a porous structure. Support member 18 having a hollow body formed of a flexible film and having microorganisms attached to the outside thereof, a substrate tank 20 for storing a substrate solution which is a nutrient source for the microorganisms, and the substrate tank 20 to the supporting member 18 The substrate pipe 22 for sending the substrate solution into the hollow body and the aeration device 24 for aerating the air from the blower 24A into the waste water 12 in the reaction tank 16.

Further, the reaction tank 16 is provided with a trough 28 for overflowing the treated water 26, and the treated water 26 overflowing into the trough 28 is treated with a treated water pump 32 via a treated water pipe 30 to the outside of the apparatus 10. Is discharged to. Further, as shown in FIG. 2, the carrying member 18 has a pair of membrane supports 36 formed of wire mesh or the like fixed to both sides of the frame 34, and a hole 38 having a diameter of 0. It is configured by providing a porous film 40 having a thickness of 5 μm or less. Then, the frame 34 and the film 40
The above-mentioned substrate pipe 22 is communicated with the hollow body 42 formed in Step 1. Further, as the porous membrane 40, for example, a microfiltration membrane, an ultrafiltration membrane, or the like can be used, and the material thereof is a polymer resin such as polysulfone-based, polypropylene-based, polyethylene-based, or polyolefin-based polymer. You can The reason why the pore 38 diameter of the membrane 40 (the pore diameter shown in FIG. 2 is actually smaller) is 0.5 μm or less is that the amount of the substrate solution that permeates the membrane 40 when the pore 38 diameter is too large. This is in order to prevent the number of cells from becoming too large and the microorganisms attached to the outer surface of the membrane 40 from penetrating the membrane 40 and entering the hollow body 42.

The installation height of the substrate tank 20 can be moved in the vertical direction (arrow 44 in FIG. 1) so that the permeation amount of the substrate solution can be adjusted according to the diameter of the hole 38 of the membrane 40. It has become. Further, as the substrate solution, methyl alcohol, ethyl alcohol, acetic acid or the like can be used. Further, sewage containing organic matter can be used as the substrate solution, but in this case, in order to prevent the membrane 40 from being clogged, it is necessary to remove solid components in the sewage in advance before use.

The usual method for adhering microorganisms to the carrying member 18 is to submerge the carrying member 18 in the wastewater 12 and allow the microorganisms floating in the wastewater 12 to naturally adhere to the outer surface of the carrying member 18. Done by. In the spontaneous attachment of microorganisms to the supporting member 18, as shown in FIG. 2, an aerobic microorganism layer 46 such as nitrifying bacteria is formed on the outer layer of the attached microorganism layer, and denitrifying bacteria are formed on the inner layer. An anaerobic microbial layer 48 such as is naturally formed by division.

Next, the operation of the sewage treatment apparatus 10 of the present invention constructed as described above will be described. The organic substances and ammonia nitrogen components in the wastewater 12 that have flowed into the reaction tank 16 are transferred to the plurality of support members 18 submerged in the reaction tank 16 in a state where air is aerated from the aeration device 24 into the wastewater 12. It is biologically treated by the attached microorganisms. That is, the carrying member 18
The outer layer of the microbial layer adhered to the aerobic microbial layer 46 forms an aerobic zone by aeration, and in this outer layer, oxidation treatment of organic matter in the wastewater 12 and ammonia nitrogen (NH _{4) are performed.} -N) nitrification treatment (one mode of oxidation treatment) is performed. On the other hand, the inner layer of the microbial layer in which the anaerobic microbial layer 48 is formed is an anaerobic zone, and the nitrate nitrogen is denitrified in this inner layer. And
Unlike autotrophic bacteria such as nitrifying bacteria that generate their own nutrients, heterotrophic bacteria such as denitrifying bacteria need to supply the nutrients required for denitrification. Therefore, according to the present invention, in this denitrification process, the substrate solution is supplied from the substrate tank 20 into the hollow body 42 of the supporting member 18, so that the nutrient source necessary for the denitrification reaction is the supporting member 18. It is possible to supply the denitrifying bacteria by permeating through the porous membrane 40.

Thus, the sewage treatment apparatus 10 of the present invention
The outer layer of the microbial layer attached to the supporting member 18 becomes the aerobic zone, the inner layer becomes the anaerobic zone, and the aerobic zone contains aerobic microorganisms and the anaerobic zone naturally contains anaerobic microorganisms. In addition, when the ammonia nitrogen (NH ₄ —N) in the wastewater is low in concentration, the nitrification reaction proceeds at the NH ₄ —N rate-determining rate in the aerobic zone and then the nutrient content in the anaerobic zone. It was confirmed experimentally that the denitrification reaction proceeds in the presence of the above, and from this fact, the supporting member 18 to which the microorganisms adhere is formed into a hollow body with the porous membrane 40 and is removed into the hollow body 42. It is configured to supply a substrate solution that is a nutrient source for nitrifying bacteria.

Thus, according to the sewage treatment apparatus 10 of the present invention, in the same reaction tank 16, oxidation treatment of an organic substance which requires an aerobic state, nitrification treatment of ammonia nitrogen, and nitric acid which requires an anaerobic state. Both the denitrification treatment of the gaseous nitrogen can be efficiently performed. Therefore, unlike the conventional sewage treatment apparatus, since two reaction tanks, an aerobic tank and an anaerobic tank, are not required, the sewage processing apparatus 10 can be made compact.

The second to sixth embodiments, which are other aspects of the present invention, will be described below with reference to FIGS. 3 to 7. still,
The same members and devices as those in the first embodiment will be described with the same reference numerals, and redundant description will be omitted. First, FIG.
A second embodiment of the sewage treatment apparatus 10 of the present invention will be described according to the above. In the second embodiment, in addition to the structure of the first embodiment, solid components in wastewater can be removed. A flat membrane-like filtration membrane 50 is arranged between a plurality of supporting members 18, and A filtered water pump 54 was provided in a filtered water pipe 52 connected to the filtration membrane 50 and extending outside the apparatus 10.
As a result, when the filtered water pump 54 is operated, the treated water biologically treated with the microorganisms attached to the supporting member 18 becomes
After being filtered by the filtration membrane 50 to remove solid components in the wastewater 12, the wastewater 12 is discharged to the outside of the apparatus 10. Also, the filtered water pipe 5
A valve 56 for adjusting the amount of treated water taken in was provided in the middle of 2, so that the retention time of the dirty water in the reaction tank 16 could be adjusted. As a result, the waste water 1 by the carrying member 18
It is possible to sufficiently perform the oxidation treatment of the organic substance in 2 and the nitrification / denitrification treatment of the nitrogen component. As described above, according to the second embodiment, the same reaction tank 16 can perform the oxidation treatment of the organic matter and the nitrification / denitrification treatment of the nitrogen component, and also remove the solid component in the wastewater 12. You can

Next, referring to FIG. 4, a third embodiment of the sewage treatment apparatus 10 of the present invention will be described. In the third embodiment, in addition to the structure of the second embodiment, microorganisms can be quickly attached to the supporting member 18. That is, the attachment pipe 58 for connecting the substrate pipe 22 and the filtered water pipe 52
(A portion indicated by a broken line in the drawing) is provided, an attachment valve 60 is provided in the attachment pipe 58, and a substrate valve 62 is further provided at the outlet of the substrate tank 20. When the microorganisms are attached to the carrying member 18, the filtered water valve 56
The substrate valve 62 is closed and the attachment valve 60 is opened, and the filtered water pump 54 is operated in this state. As a result, the wastewater 12 in the reaction tank 16 forms a flow to the substrate pipe 22 through the porous membrane 40 of the supporting member 18,
The microorganisms floating in the dirty water 12 can be forced to adhere to the outside of the membrane 40. When the microbial layer attached to the membrane 40 has an appropriate thickness, the filtered water pump 54 is stopped, the filtered water valve 56 and the substrate valve 62 are opened, and the attachment valve 60 is closed.

Next, a fourth embodiment of the sewage treatment apparatus 10 of the present invention will be described with reference to FIG. The fourth embodiment is a further improvement of the structure of the third embodiment, in which a hollow bearing member rotating shaft 64 rotatably arranged in the reaction tank 16 is provided at a predetermined interval in the axial direction. Communication port (not shown)
Then, a plurality of disc-shaped carrier members 18 are fixed. Furthermore, about half of the disc-shaped supporting member 18 is sewage 1.
The bearing member rotating shaft 64 is arranged so as to be submerged in water. Further, the substrate pipe 22 is connected to the end portion of the carrying member rotating shaft 64 extending outside the apparatus 10 so as not to hinder the rotation. As a result, the substrate solution 21 stored in the substrate tank 20 passes through the inside of the carrying member rotating shaft 64 and is supplied into the hollow body 42 of the carrying member 18 through the communication hole.

On the other hand, a plurality of disc-shaped filtration membranes 50.
Is fixed to a filtration membrane rotary shaft 66 having the same structure as the above-described carrying rotary shaft 64, and is completely submerged in the dirty water 12. Further, the filtered water pipe 22 is connected to the end of the rotary shaft 66 for the filtration membrane extended outside the device 10 so as not to hinder the rotation. Then, the supporting member 18 and the filtration membrane 50
Are arranged so that some of them overlap each other. In this case, the distance between the supporting member 18 and the filtration membrane 50 overlapping each other is preferably about 10 mm when the disk diameter is about 200 mm. Then, it is necessary to widen the interval as the disc diameter increases. Also, the disc diameter is 200
The rotation number of the supporting member 18 in the case of about mm is 3 to 10.
The rotation speed of the filtration membrane 50 is 50 to 150 r
The rotation shaft 64 for the supporting member and the rotation shaft 66 for the filtration membrane are rotated in the same direction while the rotation speed is about pm. In this case, it is preferable that the number of rotations is also changed according to the size of the disc diameter. By this rotation in the same direction, the rotation direction becomes opposite in the overlapping portion of the supporting member 18 and the filtration membrane 50.

According to the fourth embodiment constructed as described above, the same effect as that of the third embodiment can be obtained.
It has the following effects. That is, about half of the carrying member 18 is exposed on the surface of the sewage 12, and the carrying member 18 alternately repeats exposure to the atmosphere and submersion in the sewage 12, and when exposed to the atmosphere, it is removed from the atmosphere. Oxygen is supplied to the aerobic microbial layer 46 of the supporting member 18. Thereby, the aeration device 24 for aerating the dirty water 12 in the reaction tank 16 with air can be omitted.

Further, since the rotational speeds of the supporting member 18 and the filtration membrane 50 are made different, and in the overlapping portion of the supporting member 18 and the filtration membrane 50, the rotation directions are opposite to each other. The wastewater 12 in the overlapping portion of 18 and the filtration membrane 50 is agitated. Thereby, the carrying member 18
Since it is possible to prevent ammonia nitrogen in the nearby wastewater 12 from being concentrated and to treat it in a low-concentration state,
Ammoniacal nitrogen can be nitrified efficiently. Further, if the microbial layer attached to the supporting member 18 is excessively thickened, the function of aerobic microorganisms deteriorates. Since the microorganisms are peeled off, thickening of the microorganism layer can be prevented. Further, since the sewage 12 in the overlapping portion of the supporting member 18 and the filtration membrane 50 is agitated, it is possible to prevent the suspended microbial sludge from being diffused and concentrated in the vicinity of the filtration membrane 50, so that the filtration membrane 50 is clogged. Can be prevented and the filtration performance can be maintained for a long time. Further, by changing the number of the supporting members 18 and the number of the filtration membranes 50, it is possible to cope with the magnitude of the dirty water load, the fluctuation of the load, and the like.

Next, a fifth embodiment of the sewage treatment apparatus of the present invention will be described with reference to FIG. In the fifth embodiment, in the structure described in the fourth embodiment, the microorganisms are not attached to the outside of the supporting member 18, but the microorganism attaching net 68 to which the microorganisms are attached is attached to the outside of the supporting member 18 in advance. is there. According to the fifth embodiment, in addition to the effects of the fourth embodiment,
By using the microorganism-attaching net 68, the type of the microorganisms to be attached, the amount of the attached microorganisms, etc. can be arbitrarily set, and thus it is suitable when the organic matter load in the wastewater is large.

Next, a sixth embodiment of the sewage treatment apparatus of the present invention will be described with reference to FIG. In the sixth embodiment, in addition to the structure described in the fourth embodiment, the adsorptive powder 70 such as powdered activated carbon is added to the sewage 12 in the reaction tank 16. As a result, in addition to the effects obtained in the fourth embodiment, the sewage 12
The pigment component and the odor component therein can be adsorbed and removed by the adsorptive powder 70.

In this embodiment, as a method for attaching the microorganisms to the supporting member 18, the floating bacteria in the waste water 12 are naturally attached to the supporting member 18. However, it is not limited to natural attachment, and first, an anaerobic microorganism whose main bacterium is a denitrifying bacterium is artificially attached to the outside of the supporting member 18, and an aerobic microorganism whose main bacterium is a nitrifying bacterium is attached to the outside thereof. It may be artificially attached. In addition, the filtration membrane 5 of this embodiment
When the low pressure reverse osmosis membrane is used for No. 0, the same effect as the addition of the adsorptive powder 70 described in the sixth embodiment can be obtained, and the generation of sludge derived from the adsorptive powder 70 can be eliminated.

[0028]

As described above, according to the sewage treatment apparatus of the present invention, in the same reaction tank, an oxidation treatment of an organic substance which requires an aerobic condition and a nitrification treatment of an ammonia nitrogen component,
It is possible to efficiently perform both the denitrification treatment of the nitrate nitrogen component which requires the anaerobic state. As a result, like the conventional sewage treatment apparatus, two reaction tanks, an aerobic tank and an anaerobic tank, are used.
A nitrogen component in wastewater can be efficiently removed without the need for a tank, and the wastewater treatment device can be made compact.

Further, when the supporting member formed in the shape of a hollow disk is fixed to the rotating shaft and a part of the supporting member is exposed on the surface of the waste water, an aerator for supplying air into the waste water of the reaction tank. Can be omitted. In addition, if a filtration membrane for filtering solid components is provided in the reaction tank in addition to the above-mentioned supporting member, it is possible to remove solid components in addition to oxidizing treatment of organic substances and nitrification / denitrification treatment of nitrogen components in the same reaction tank. You can

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a first embodiment of a wastewater treatment apparatus according to the present invention.

FIG. 2 is an enlarged view of part A of FIG.

FIG. 3 is an explanatory view illustrating a second embodiment of the wastewater treatment apparatus according to the present invention.

FIG. 4 is an explanatory diagram illustrating a third embodiment of the wastewater treatment apparatus according to the present invention.

FIG. 5 is an explanatory view explaining a fourth embodiment of the sewage treatment apparatus according to the present invention.

FIG. 6 is an explanatory view explaining a fifth embodiment of the sewage treatment apparatus according to the present invention.

FIG. 7 is an explanatory diagram illustrating a sixth embodiment of the sewage treatment apparatus according to the present invention.

[Explanation of symbols]

10 ... Sewage treatment device 12 ... Sewage 14 ... Sewage inflow pipe 16 ... Reaction tank 18 ... Supporting member 20 ... Substrate tank 22 ... Substrate piping 24 ... Aeration device 26 ... Treated water 30 ... Treated water piping 32 ... Treated water pump 36 ... Membrane support of carrier member 38 ... Porous membrane pores 40 ... Porous membrane 42 ... Hollow body 46 ... Aerobic microbial layer 48 ... Anaerobic microbial layer 50 ... Filtration membrane 52 ... Filtered water piping 54 ... Filtered water pump 68 ... Microbe-attached net 70 ... Adsorbent powder

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yutaka Okuno 1-1-14 Uchikanda, Chiyoda-ku, Tokyo Inside Hitachi Plant Construction Co., Ltd. (72) Yoshiko Watanabe 5-11-11 Nishioka, Toyohira-ku, Sapporo, Hokkaido -8 (56) Reference JP-A 63-310696 (JP, A) JP-A 4-193396 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C02F 3/02- 3/10 C02F 3/28-3/34

Claims (5)

(57) [Claims] 1. A reaction tank into which sewage flows, and a submerged water in the sewage water in the reaction tank, which is formed as a hollow body with a porous membrane and has a microorganism attached to the outer surface thereof. A carrier member for forming a microbial layer consisting of two layers of an outer layer of aerobic microorganisms and an inner layer of anaerobic microorganisms; and a substrate supply device for supplying a substrate solution which is a nutrient of the anaerobic microorganisms into the hollow body of the carrier member. And an aerator for supplying air into the wastewater in the reaction tank, wherein the outer layer of the microbial layer formed on the supporting member performs an oxidation treatment of an organic matter in the wastewater and a nitrification treatment of an ammonia nitrogen component. At the same time, a sewage treatment apparatus is characterized in that the inner layer of the microorganism layer is subjected to a denitrification treatment of nitrate nitrogen components. 2. A filtration membrane for filtering solid components in wastewater is provided in the reaction tank.
Sewage treatment equipment. 3. A reaction tank into which sewage flows in, and a reaction tank fixed in the reaction tank so as to face a communication port formed at a predetermined interval in the axial direction of a hollow rotating shaft for a supporting member rotatably arranged in the reaction tank. In addition, it is provided so that a part of it is exposed on the surface of the sewage, and the microorganisms adhere to the outer surface of the hollow disk formed by the porous membrane to attach the microorganisms to the outer layer of the aerobic microorganisms and anaerobically. A plurality of supporting members forming a microbial layer composed of two inner layers of sexual microorganisms, and nutrients of the anaerobic microorganisms in the hollow disks of the plurality of supporting members via the rotating shaft for the supporting members. A substrate supply device for supplying a substrate solution, and while rotating the supporting member, an oxidation treatment of organic matter in the wastewater and a nitrification treatment of ammonia nitrogen components are performed in an outer layer of the microbial layer formed on the supporting member. The inner layer of the microbial layer A sewage treatment device characterized by performing denitrification treatment of nitrate nitrogen components in the. 4. A communication provided in the reaction tank at a predetermined interval in the axial direction of a hollow filtration membrane rotating shaft for collecting filtered water, which is rotatably disposed in the reaction tank. A plurality of disc-shaped filters that are fixed so as to face the mouth, are entirely submerged in wastewater, and are arranged so as to partially overlap the plurality of carrying members fixed to the carrying member rotation shaft. The sewage treatment apparatus according to claim 3, further comprising a membrane. 5. The porous membrane forming the supporting member is a microfiltration membrane or an ultrafiltration membrane having a pore diameter of 0.5 μm or less, wherein the porous membrane is a microfiltration membrane or an ultrafiltration membrane. Sewage treatment equipment.