JPH11300379A - Biological treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the defective cleaning of a carrier in the biological treating device for aerobically purifying the water to be treated by the use of a flowable carrier carrying a microorganism. SOLUTION: A carrier T to be placed in a biological treating tank 2 is formed with a material having a specific gravity equal to or slightly lower than that of water and free of the open cells communicating with the inside. All the surface openings are communicated with any of the other surface openings, and the inside dimensions are so set that the bubbles are not caught with plural wings arranged regularly. Since the air is not held in the carrier, the apparent sp.gr. is not changed, and the carrier exhibits stabilized flowability. As the wings are furnished, the flowability is increased, and agitation is ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a biological treatment apparatus for purifying domestic wastewater and human wastewater by the activity of microorganisms.

[0002]

[Prior Art] Decomposition of microorganisms into domestic wastewater and human wastewater
BACKGROUND ART Biological treatment apparatuses for purifying by utilizing assimilation have been widely used, and various types of biological treatment apparatuses have been proposed. JP-A-6-23065 describes an example of such a processing apparatus. This processing apparatus uses a three-dimensional network structure having a specific gravity similar to that of water using, for example, a polyurethane foam as a carrier for supporting microorganisms. The point formed in the thing with is featured. When performing the purification treatment in the same processing apparatus, by supplying air from the lower part by a diffuser tube or the like into the processing tank in which the carrier carrying the microorganisms is stored, the carrier is given buoyancy and floated. While maintaining the state, the water to be treated is supplied from above the treatment tank and passed downward between the carriers. While the water to be treated passes between the carriers,
The organic matter is decomposed or assimilated by the microorganisms carried on the carrier, and the water to be treated is purified.

In the above-described processing apparatus, the carrier is washed at a required time in order to prevent a reduction in processing capacity. When the carrier cleaning process is performed, air is supplied in an amount 5 to 10 times that of the normal operation to generate a strong gas-liquid mixed flow in the processing tank. Since the carrier is not fixed in the treatment tank but exists in a floating state, the carrier is stirred by a gas-liquid mixed flow, and as a result, solids such as SS and flocs of growing microorganisms trapped between the carriers are removed. Dropped and removed.

[0004]

The conventional biological treatment apparatus uses a carrier having a three-dimensional network structure as a carrier for supporting microorganisms. For this reason, air supplied during the processing step or the cleaning step may be trapped in the network structure and may not easily escape from the carrier.
The carrier holding air therein has a reduced apparent specific gravity and an increased buoyancy, resulting in a decrease in fluidity. Further, since the apparent specific gravity of the carrier varies depending on the amount of air holding, the fluidity of the carrier becomes uneven. As a result of such a phenomenon, there occurs a problem that effective cleaning is hindered and cleaning failure occurs.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems in a biological treatment apparatus for purifying treated water under aerobic conditions by using a large number of flowable carriers carrying microorganisms. It provides a means to solve. The feature of the means for solving the problems adopted by the present invention is that the carrier is formed of a material having a specific gravity equal to or slightly smaller than that of water, and having no continuous pores leading to the inside. .

Further, the carrier is formed of a material having a specific gravity equal to or slightly lower than that of water and having no continuous pores communicating with the inside, and has a plurality of regularly arranged vanes, and all surface openings are provided. May be configured to communicate with any of the other surface openings, and the internal dimension of the internal space may be set to a size that does not trap air bubbles.

[0007] By forming the carrier for supporting microorganisms from a material having a specific gravity equal to or slightly smaller than that of water, the carrier is maintained in a floating state in the water to be treated. However, since the specific gravity is set to be equal to or slightly smaller than that of water, the carrier can exhibit necessary and sufficient fluidity in the washing step of feeding a large amount of air. In addition, since the material for forming the carrier does not have continuous pores communicating with the inside, air is not taken in and held inside.
Therefore, there is no possibility that the apparent specific gravity of the carrier fluctuates, so that the fluidity of the carrier is kept uniform and a good washing effect is obtained.

The carrier has a structure in which a plurality of blades are regularly arranged, and all the surface openings communicate with any other surface openings. When the normal size is set to a size that does not capture bubbles, the following functions are exhibited. First, by providing a plurality of regularly arranged blades, it becomes easier to receive the action of the gas-liquid mixed flow generated by a large amount of air supply during the cleaning process, so the fluidity of the carrier increases,
Stirring is assured. Since all the surface openings are configured to communicate with any other surface openings, water and air can pass through the carrier. The efficiency of contact with microorganisms is increased, and during the washing step, the gas-liquid mixed flow can easily remove SS and excess flocs accumulated inside the carrier. Further, by setting the inner dimension of the internal space to a size that does not trap air bubbles, air is no longer retained in the carrier, so that there is no possibility that the carrier will fluctuate in apparent specific gravity.

In the case where a carrier having the above-mentioned blade body is used, large and small carriers may be used in combination, and there is no blade body made of a material having a specific gravity equal to or slightly smaller than that of water. Carriers may be mixed. Since the carrier having the blade body is liable to receive the flow energy, even if the carrier without the blade body is mixed in an appropriate amount, it is possible to cause a reliable stirring state to appear during the washing step.

[0010] A holding member for preventing passage of the carrier may be provided at a position slightly below the storage level of the water to be treated in the treatment tank in which the carrier is stored. Since the entire carrier is immersed in the water to be treated by the pressing member, there is no portion that is not in contact with the water to be treated. Further, although solids tend to accumulate in the water surface area of the water to be treated, the carrier is held below the water surface by the pressing member, so that contact between the carrier and the solids can be avoided.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIGS. 1 and 2
FIG. 1 shows an example of the biological treatment device 1 according to the present invention. The treatment apparatus 1 includes a biological treatment tank 2 for purifying treated water by the biochemical activity of microorganisms, a treated water separation tank 3 for temporarily storing treated water obtained by purifying treatment water in the biological treatment tank 2, Are integrally connected to each other. Biological treatment tank 2
Has a large number of carriers T for carrying microorganisms, and an aeration unit 4 is provided below. The aeration means 4 is composed of two blowers 5, 6 and diffuser tubes 7, 8 connected to the two blowers, respectively.
In the cleaning process, only the air blower 7 and the other air blower 6 and the air diffuser 8 are used, or both the blowers 5 and 6 and the air diffusers 7 and 8 are used to supply air. Increase volume.

The treated water separation tank 3 communicates with the biological treatment tank 2 near the bottom through a communication portion 9 so that the inflowed treated water flows out from the top to the outside. A small amount of solids mixed in the treated water settles while being stored in the separation tank 3. The sediment accumulated at the bottom is extracted by an appropriate discharging means 20 and transferred to a separately provided solid storage tank, or is circulated and returned to an anaerobic treatment tank provided upstream of the biological treatment tank 2. . If necessary, an inclined surface structure N for guiding the sediment to the vicinity of the discharge means 20 may be provided at the bottom of the separation tank 3.

In order to prevent the carrier T in the biological treatment tank 2 from migrating to the separation tank 3, in FIG. 1A, the carrier separation plate 1 is located at a position slightly above the air diffuser 7 in the biological treatment tank 2.
0 is provided. Alternatively, it may be provided at a position slightly lower than the air diffusers 7 and 8. The carrier separation plate 10 is made of, for example, a perforated plate or a mesh body, and is configured such that a fluid such as water or air can easily pass through, but does not allow the carrier T to pass. The position where the carrier separation plate 10 is provided is shown in FIG.
The communication part 9 located at the boundary between the biological treatment tank 2 and the separation tank 3 may be used.

The carrier T accommodated in the biological treatment tank 2 and supporting microorganisms is made of, for example, a synthetic resin such as polypropylene or polyethylene, and has a specific gravity equal to or slightly smaller than that of water (specifically, 0). .800-0.9
99 range). Since the specific gravity of the water to be treated supplied to the biological treatment tank 2 is usually considered to be slightly larger than that of water, the carrier is floated in the biological treatment tank 2 by setting the specific gravity of the carrier to the specific gravity of water or less. be able to.
Further, since the specific gravity is set to be equal to or slightly smaller than the specific gravity of water, there is no possibility that the ratio of buoyancy to the weight of the carrier becomes excessively large and the fluidity is not lost, and the carrier fits under the water surface moderately. Further, since the carrier is formed of a material having no continuous pores leading to the inside, air is not taken in and held inside, and therefore, there is no possibility of causing a change in apparent specific gravity.

The specific shape of the carrier T is not particularly limited, but there is no possibility of retaining air bubbles therein,
It is also desirable that adjacent carriers are difficult to share and do not mesh with each other. The carrier T illustrated in FIG.
Means that eight identical blades H are equiangular (45
Degrees), and the plane shape and the front shape are almost regular octagons, and the whole shape is a polyhedron. At the center of the blade body H in the height direction, a narrow connecting member J for connecting adjacent blade bodies H, H is provided. The carrier T of FIG. 4 is obtained by changing the center axis P of the carrier T of FIG. 3 to a hollow cylindrical axis Q. The carrier T shown in FIG. 5 has three ring members R arranged coaxially at the center, and wing members H arranged radially around these ring members R. Further, the carrier T shown in FIG. 6 has a quarter circular blade body H around a ring body R arranged at the center.
And the entire shape is substantially spherical, and the upper and lower sides of the annular connecting member J have different blade positions. In other words, the lower blades H (d) are configured such that the lower blades H (d) are displaced from the upper blades H (u) by half the angle (30 degrees) formed by the adjacent blades H, H. ing.

The carrier T provided with the blade body H as illustrated in FIGS. 3 to 6 has the following characteristics. First, by providing a plurality of blades H, it becomes easier to receive the flow energy of water or air, so that the flowability is improved. Further, since the specific surface area increases, the amount of microorganisms retained per carrier T increases, and the treatment capacity of the water to be treated increases. Connecting member J
Plays a role in preventing deformation of the blade body H to increase the strength and preventing the carriers T from meshing with each other at the portion of the blade body H. The inner space S of the carrier T surrounded by the blade body H, the connecting member J, and the like is formed as an open space in which at least two sides are open. That is, since any opening K (shown by hatching in the figure) is configured to communicate with any other opening K, water or air can easily flow through the carrier T, The contact efficiency between the water to be treated and the microorganisms carried on the carrier T is good. Furthermore, since the internal dimension of the internal space of the carrier T is set to a size that does not trap air bubbles, there is no danger that the air bubbles will be held inside and the apparent specific gravity will fluctuate.

In order for the carrier T to exhibit the above characteristics, it is desirable that the following conditions are satisfied. First, the size of the carrier T is in a range of 5 to 50 mm in diameter. 5 in diameter
If it is less than mm, the internal space is narrowed and air bubbles are easily held. When the diameter exceeds 50 mm, the specific surface area becomes small, so that the amount of microorganisms retained per unit volume and the amount of contact with the water to be treated decrease, and the treatment efficiency decreases. Therefore, the preferable value of the diameter of the carrier T is set in the above range. In order to secure the amount of microorganisms to be carried and to easily receive the flow energy, the total surface area of the blade body H is set to be one third or more of the surface area when the carrier T is assumed to be a solid body. Conditions for allowing water and air to flow through the internal space S of the carrier T and preventing air bubbles from being trapped in the internal space S are as follows: the opening area of each opening K is 4 mm ² or more, and a sphere having a diameter of 1 mm Is to set the inner dimension so that the inner space S can move in the inner space S without simultaneously touching three or more surfaces constituting the inner space S.

The treatment of the water to be treated in the biological treatment apparatus 1 constructed as described above is executed as follows. The upstream area above the carrier separation plate 10 in the biological treatment tank 2 is an effective treatment space, and the carrier T is stored therein.
The filling rate of the carrier T is usually about 50 to 85% of the effective processing space in order to secure the fluidity of the carrier T. When the carrier T is stored in the biological treatment tank 2 and the water to be treated is supplied, the carrier T receives buoyancy because the specific gravity of the carrier T is slightly smaller than the water to be treated, and floats. As shown in FIG. The biological filtration layer F is formed in the upper region of the tank 2. In order to perform aerobic treatment, air is sent into the tank 2 from one of the air diffusers 7 of the aeration means 4. The supply amount is adjusted so that the carrier T forming the biological filtration layer F does not flow, and is set to, for example, a rate of 0.1 to 10.0 m ³ / hour per 1 m ^{3 of the} effective treatment space. In this state, when the water to be treated is fed little by little into the biological treatment tank 2 from the upper part, while the water to be treated flows downward through the gap of the carrier T, the organic substances contained in the water to be treated are removed from the carrier. Decomposed or assimilated by microorganisms carried on the T surface, and as a result, purification of the water to be treated proceeds.
The treated water obtained by the purification treatment is transferred from the bottom of the biological treatment tank 2 to the separation tank 3 through the communication part 9. Slight solids contained in the treated water are settled and separated in the separation tank 3,
Only the supernatant is drained out. The sediment accumulated at the bottom of the separation tank 3 is pulled out and removed by an appropriate discharging means 20.

Next, the cleaning step in the biological treatment apparatus 1 will be described. To carry out the washing of the carrier T, FIG.
As shown in (1), about 1.1 to 10 times the amount during normal operation (for example, effective) from both the two air diffusers 7 and 8 of the aeration means 4 or from the air diffuser 8 for washing into the biological treatment tank 2 Processing space 1
m supplies air ³ per 1-30 m ³ / h). At this time, the supply of the water to be treated may be stopped or continued. Since an appropriate distance is provided between the biological filtration layer F and the carrier separation plate 10, a large amount of air is supplied, so that a violent gas-liquid mixed flow is generated in the biological treatment tank 2 and the biological filtration The carrier T forming the layer F is dispersed and flows. Since the carrier T of the present embodiment has a plurality of blades, it is easy to receive the flow energy of the gas-liquid mixed flow, and therefore has excellent flowability. Moreover, since the carrier T has a structure that does not hold air inside, there is no change in apparent specific gravity, and therefore, it is possible to obtain a uniform flow state. As a result of the flow of the carrier T, S trapped between the carriers T
Solids such as S and surplus flocs of microorganisms that have grown due to the decomposition and assimilation of organic substances fall off. The solids that have fallen out are settled out and eliminated by the discharge means 20.

[Second Embodiment] By manufacturing the carrier T using a material having no open cells, there is no fear that the apparent specific gravity fluctuates due to the retention of air.
It is possible to ensure the fluidity during the washing step even if the blade does not have a blade body. FIG. 7 exemplifies such a carrier T, and has a cylindrical shape shown in FIG. 7A, a dice shape having chamfered corners and ridges in FIG. In addition to the short column shape having the protrusion c), a spherical shape, a donut shape (a torus shape), a hexagonal column shape, a protrusion having a projection on the outer peripheral surface of the cylinder, or a rib in the axial direction are conceivable. In the case of the present embodiment, the size of the carrier T is preferably about 2 to 25 mm.

[Third Embodiment] FIG. 8 shows a different embodiment of the biological treatment apparatus 1 according to the present invention. The biological treatment tank 2 and the sedimentation tank 12 are connected by a communication pipe 11. It is configured. In the first embodiment, since the biological treatment tank 2 and the treated water separation tank 3 are directly in communication at the bottom, the separation tank 3 was easily affected by the flow state in the biological treatment tank 2. In the present embodiment, since the biological treatment tank 2 and the sedimentation tank 12 are connected via the communication pipe 11, the sedimentation tank 1
2 is not affected by the flow state in the biological treatment tank 2. Accordingly, sedimentation and separation of a small amount of solids contained in the treated water transferred from the biological treatment tank 2 can be stably performed.

The sediment S separated from the treated water by sedimentation
The discharging means 21 for extracting and removing the
Is sufficient, but it does not prevent the biological treatment tank 2 from being provided with the elimination means 22 for extracting solids falling off from the carrier T in the washing step.

[Fourth Embodiment] The present invention can be applied to a biological treatment apparatus 1 for performing aerobic treatment while flowing a carrier T as shown in FIG. The carrier flow type biological treatment tank 2 performs a purification treatment step by sending a little more air from the aeration device 4 into the water to be treated and keeping the carrier T in a gentle fluidized state. The carrier T provided with the plurality of blades H described above can also obtain suitable results even when applied to such a carrier flow type biological treatment tank 2. In the present embodiment, the filling rate of the carrier T is set to about 5 to 85%.

[Fifth Embodiment] As shown in FIG.
At a position slightly below the storage water level L of the water to be treated in the biological treatment tank 2, a carrier holding member made of a mesh body, a perforated plate, or the like, which does not allow the carrier T to pass but can easily pass a fluid such as air or water. Forty may be provided. By providing the carrier pressing member 40, all of the carrier T is immersed in the water to be treated, so that the contact with the water to be treated becomes efficient. Further, since it is possible to avoid contact between the carrier T and the solid matter accumulated near the water surface of the biological treatment tank 2, it is possible to avoid a decrease in the fluidity of the carrier T due to the adhesion of the solid matter.

[Sixth Embodiment] The carrier T used in the biological treatment apparatus 1 according to the present invention is not limited to one type, and it does not prevent the use of a mixture of two or more different types. . For example, the carrier T ₁ provided with the blade body H (FIG. 3)
-6) may be used in combination of two or more. Alternatively, as shown in FIG. 11, a carrier T ₁ having a blade body and a carrier T having no blade body having a smaller diameter.
₂ (see FIG. 7) can be mixed and stored in the biological treatment tank 2. In this case, the carrier T ₁ provided with the blade body H
Can is because prone to flow energy, even if a certain amount mixed carrier T ₂ without a sail body, to reliably flow the entire carrier in a bath. The mixing ratio of the carrier T ₂ having no blade to the carrier T ₁ having the blade is T ₂ / T
₁ is set to be in the range of about 0.05 to 1.0.

Seventh Embodiment A wastewater treatment system as illustrated in FIG. 12 can be constructed using the biological treatment apparatus 1 according to the present invention. The wastewater treatment system shown in the figure is aerobic treatment described in the first embodiment following the first anaerobic treatment tank 13 and the second anaerobic treatment tank 14 for anaerobically treating the water to be treated (raw water). Biological treatment tank 2 for chemical treatment
And a treated water separation tank 3 connected in series. In the first anaerobic treatment tank 13, solids in the water to be treated (raw water) are separated, and the solids that cannot be separated are removed from the second anaerobic treatment tank 14.
To separate and disassemble. Thereafter, in the biological treatment tank 2, the organic matter in the water to be treated is aerobically treated and purified by the activity of the microorganisms carried on the carrier T. The obtained treated water is transferred to the adjacent separation tank 3, and only the supernatant liquid is separated and discharged.

In the wastewater treatment system of the present embodiment, the discharge path 30 for removing solids settled and separated from the treated water in the treated water separation tank 3 to the outside is provided in the first anaerobic treatment tank 1.
3 to form a circulation channel. Therefore,
The sediment generated in the separation tank 3 and the solid matter generated as a result of the washing step in the biological treatment tank 2 are returned to the first anaerobic treatment tank 13 through the discharge path 30.

The embodiment of the present invention is not limited to the above-described embodiment, and does not hinder appropriate application and modification in accordance with the state of implementation.

[0029]

According to the present invention, in a biological treatment apparatus for performing aerobic treatment, a flowable carrier for carrying microorganisms is provided.
By using a material that does not have continuous pores inside,
Since the carrier does not take in air to cause a change in apparent specific gravity, the fluidity of the carrier is stabilized. Further, by providing the carrier with a plurality of blades and keeping no air inside, the carrier is more likely to receive flow energy, and as a result, the fluidity of the carrier is improved. Therefore, the carrier cleaning step in the biological treatment apparatus can be effectively performed, and the problem of poor cleaning is eliminated.

[Brief description of the drawings]

FIG. 1 relates to a first embodiment of the present invention, in which FIG. 1 (a) is a cross-sectional view of a biological treatment apparatus in a purification treatment step, and FIG. 1 (b) shows another aspect of the biological treatment apparatus. It is sectional drawing of a principal part.

FIG. 2 relates to the first embodiment of the present invention and is a cross-sectional view of the biological treatment apparatus during a cleaning step.

FIG. 3 shows an example of a carrier used in the biological treatment apparatus according to the present invention, wherein FIG. 3 (a) is a plan view and FIG.
Is a front view, and FIG.

FIG. 4 shows an example of a carrier used in the biological treatment apparatus according to the present invention, wherein FIG. 4 (a) is a plan view and FIG.
Is a front view, and FIG.

FIG. 5 shows an example of a carrier used in the biological treatment apparatus according to the present invention, wherein FIG. 5 (a) is a plan view and FIG.
Is a front view, and FIG.

FIG. 6 shows an example of a carrier used in the biological treatment apparatus according to the present invention, wherein FIG. 6 (a) is a plan view and FIG.
Is a front view, and FIG.

FIG. 7 is a perspective view according to a second embodiment of the present invention, showing another example of the carrier.

FIG. 8 is a sectional view of a biological treatment apparatus according to a third embodiment of the present invention.

FIG. 9 is a sectional view of a biological treatment apparatus according to a fourth embodiment of the present invention.

FIG. 10 is a sectional view of a biological treatment apparatus according to a fifth embodiment of the present invention.

FIG. 11 is a sectional view of a biological treatment apparatus according to a sixth embodiment of the present invention.

FIG. 12 relates to a seventh embodiment of the present invention, and is a cross-sectional view showing an example of a wastewater treatment system constructed using the biological treatment device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Biological treatment apparatus 2 ... Biological treatment tank 3 ... Treated water separation tank 4 ... Aeration means 5, 6 ... Blower 7, 8 ... Aeration tube 9 ... Communication part 10 ... Carrier separation plate 11 ... Communication tube 12 ...
Sedimentation tank 20 ... Discharge means 40 ... Carrier holding member F ...
Biological filtration layer H: feather body J: connecting member K: opening
L: Storage water level of treated water N: Inclined surface member P: Central axis
Q: Cylindrical shaft R: Ring body S: Internal space T: Carrier

Claims (5)

[Claims] 1. An apparatus for purifying water to be treated under aerobic conditions with a large number of flowable carriers carrying microorganisms, wherein the carrier has a specific gravity equal to or slightly smaller than that of water, and A biological treatment apparatus characterized by being formed of a material that does not have continuous pores leading to water. 2. An apparatus for purifying water to be treated under aerobic conditions with a large number of flowable carriers carrying microorganisms, wherein the carrier has a specific gravity equal to or slightly smaller than that of water, and It is formed of a material that does not have continuous pores leading to the air, comprises a plurality of regularly arranged vanes, and is configured such that all surface openings communicate with any other surface openings, A biological treatment apparatus characterized in that the inner dimension is set to a size that does not trap air bubbles. 3. The biological treatment apparatus according to claim 2, wherein carriers having different sizes are mixed. 4. The biological treatment apparatus according to claim 2, wherein a carrier made of a material having a specific gravity equal to or slightly smaller than that of water and having no blade body is mixed. 5. The living organism according to claim 1, wherein a holding member for preventing passage of the carrier is provided at a position slightly below the storage level of the water to be treated in the treatment tank in which the carrier is stored. Processing equipment.