JPH11226588A - Microorganism carrier element for water treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microorganism carrier element for water treatment which has good adhesion efficiency of microorganisms and does not need washing after use for a long time when it is used in a fluidized bed type treating tank. SOLUTION: A number of these carrier elements 12 are fed in a fluidized bed type water treating tank wherein waste water is biochemically treated to form a microorganism carrier. This carrier element 12 is a cylindrical body provided radially with a number of fins 14 at least on the outer peripheral face side. These runs 14 take an action for making the carrier element 12 rotate on its own axis by receiving water flow when the carrier element 12 rotates and floats in water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microbial carrier element for forming a microbial carrier by putting a large number of them into a fluidized-bed water treatment tank for biochemically treating sewage, and a fluidized-bed water treatment using the same. Related to the device. Here, a fluidized bed water treatment using aerobic bacteria will be described as an example, but the same applies to anaerobic bacteria.

[0002]

2. Description of the Related Art Conventionally, biochemical water treatment using aerobic bacteria or anaerobic bacteria has been widely performed from the environmental point of view as a method of treating wastewater such as industrial wastewater or domestic wastewater. .

In order to efficiently perform the biochemical water treatment from the bottom to the upper middle part, fluidized bed water treatment is becoming mainstream (Japanese Patent Publication No. 61-2440 / Japanese Patent Application Laid-Open No. 6-7789). -See Japanese Patent Publication No. 7-20587 and the like). The fluidized bed is formed by circulating a filter bed formed of a large number of microbial carriers in treated water with an upwardly-agitated flow generated by a diffuser or the like.

[0004] As a microorganism carrier (filter material) for a water purification tank, for example, Japanese Patent Publication No. Sho 61-2440 discloses the following structure.

[0005] As a filter material for a water purifying tank, an outer peripheral portion is formed by a water-supplying tank formed of hollow sponge-like resin, rubber, non-woven fabric, resin or rubber and vegetable fiber, and the specific gravity approaches 1 when containing water. (See Japanese Utility Model Laid-Open No. 55-65198) or a microorganism-implanted body made of a synthetic resin having a hollow body with a hole and a concave and convex shape (see Japanese Utility Model Application Laid-Open No. 55-65198). No. 115399), and a filter medium containing a foamed plastic having open cells inside a similarly formed spherical body (Japanese Utility Model Application Laid-Open No. 55-1153).
No. 99). Then, in the above-mentioned patent publication, the problems of the above-mentioned filter medium are described as follows.

[0006] "These are ... they accumulate on the bottom of the oxidation tank due to the growth of aerobic bacteria and the attachment of a lot of scum and algae due to long-term use, and their functions are rather deteriorated. In the meantime, the function of the septic tank will be interrupted in the meantime, which is no different from the use of more gravel and stone blocks. "And, in order to solve those problems, the sewage purification sphere of the following configuration Proposed.

[0007] The whole is formed in a spherical shape, and is composed of a frame body having a large number of gaps formed on the peripheral surface thereof. The frame can be divided and assembled freely at the center, and is united at the center along the diameter direction of the spherical body. In addition, a tubular body having an open end at the outer periphery of the spherical body is fixed to the outer peripheral frame, and a plug for closing the opening is made detachable. A reinforcing pipe parallel to the surface is attached to the outer peripheral frame so as to face the reinforcing pipe attached to the spherical body on the opposing face, and is appropriately spaced inward from each of the reinforcing pipes, and the reinforcing pipe facing in the center A sphere for purifying sewage, characterized in that a large number of rods and a small number of rods are attached to the sphere. "

[0008]

However, the above-mentioned microorganism carrier (sewage purification sphere) is presumed to cause the following problems.

(1) The sphere is a divided assembly having a complicated structure, and requires a number of molds for manufacturing.

(2) A sphere formed of a hard synthetic resin,
In addition to being bulky during transportation or the like, even if an outer peripheral frame (guard) is present, there is a possibility that the outer frame may be damaged due to mutual collision or the like.

(3) When the microorganisms alone (spheres) are swirled and floated, there are few intersections where the flow of water is stagnant, the adhesion efficiency of microorganisms is not good, and on the contrary, microorganisms and the like proliferate,
Clogging occurs and still requires periodic cleaning. When clogging occurs, aerobic bacteria on the inner side are killed, which in turn causes contamination.

[0012] In view of the above, the present invention provides a microorganism for fluidized-bed water treatment which is simple to produce, has little damage, has good microorganism adhesion efficiency, and does not require washing after long-term use. It is intended to provide a carrier element.

[0013] Another object of the present invention is that even after long-term use,
An object of the present invention is to provide a fluidized-bed water treatment apparatus that does not require washing of the microorganism carrier.

[0014]

Means for Solving the Problems The present inventors have made intensive efforts to solve the above-mentioned problems, and as a result, have a microbial carrier element for water treatment having the following constitution and a fluidized-bed water treatment apparatus using the same. I thought.

The microbial carrier element for water treatment of the present invention is a carrier element for forming a microbial carrier by putting a large number into a fluidized-bed water treatment tank for biochemically treating sewage. It is a cylindrical body provided with a plurality of radial fins at least on the outer peripheral surface side.

The fluidized bed water treatment apparatus of the present invention is a fluidized bed water treatment apparatus for biochemically treating sewage, comprising a water treatment tank and a large number of water treatment tanks. A microorganism carrier comprising a carrier element, and an aerator for agitating and circulating the microorganism carrier in water, wherein the carrier element is a cylindrical body having a plurality of fins radially at least on an outer peripheral surface side. And

In the above-mentioned carrier element and water treatment apparatus, it is preferable that the tubular body has a plurality of fins on the inner peripheral surface side. Further, it is desirable that the fins on the outer peripheral surface side of the tubular body positively generate rotation on the tubular body by the water flow, and that the specific gravity of the tubular body be less than 1.0. Is desirable. Further, it is desirable that the cylindrical body is a molded body of a polyolefin resin.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

(1) FIG. 1 shows an example of the microorganism carrier element of the present invention.

The microorganism carrier element 12 is a carrier element for forming a microorganism carrier by putting a large number of the microorganism carrier elements into a fluidized-bed type water treatment tank for biochemically treating sewage. And a large number of cylindrical bodies.

The shape of the tubular body is a cylindrical body in FIG. 1, but may be a square tubular body (hexagonal rectangular tubular body in the illustrated example) 12A as shown in FIG. . The polygon is arbitrary as long as it can be formed from a triangle to a dodecagon. In the case of a polygon, the rectangular cylindrical body side surface 18 receives a water flow,
Orbital motion (water floating swirling motion: see solid arrow in Fig. 4)
Is more likely to occur.

At this time, the shape specification of the cylindrical body is as follows, although it varies depending on the size (capacity) of the water treatment tank, the type of the microorganisms to be implanted, and the like.

Diameter of cylindrical body (including fins on the outer peripheral surface side): 3 to 30 mm (preferably 8 to 15 mm), length of cylindrical body: 3 to 30 mm (preferably 8 to 15 mm), Wall thickness: 0.1 to 2 mm (preferably 0.2 to 1.0 mm, more preferably 0.2 to 0.6 mm). Here, it is desirable that the thickness is thinner, when molded with a soft plastic, the carrier element itself due to water flow has a moderate bending deformation,
This is because adhesion and accumulation of surplus microorganisms can be prevented.

Here, the fins 14 and 16 which are characteristic components of the present invention are primarily formed by forming a large number of corners (intersections) on the tubular body 12 where microorganisms easily adhere to each other. It has the effect of increasing the efficiency of adhering microorganisms per volume.
The fins 14 on the outer peripheral surface have an effect of causing the cylindrical body 12 to generate a rotational motion by the water flow together with the effect.

Here, the projection length and pitch of the fins 14 are, in principle, from the viewpoint of the efficiency of microbial adhesion, as long as the fins 14 have a protruding length capable of forming corners (intersections) where microorganisms can easily adhere. More is better. However, in the present invention, from the viewpoint of causing the microorganism carrier element (cylindrical body) to rotate by water flow, the protrusion length is too short or too long, and furthermore, the pitch is too wide or too narrow. It is not desirable to pass too much. Further, if the protrusion length of the fins 14 is too long or the pitch is too narrow, even if the carrier element rotates, it becomes difficult for the surplus microorganisms to peel off. The specific specifications of the fins 14 and 16 are as follows.

The thickness of the fin 14 is substantially the same as the thickness of the cylindrical body 12 for reasons such as molding. The protruding length of the fin 14 on the outer peripheral surface side is 1/30 to 1/1 / the diameter of the cylindrical body.
10 (desirably 1/20 to 1/15), that is, 0.2
３3 mm (desirably, 0.3 to 1 mm). The pitch of the fins 14 is such that the number of the fins 14 is 3 to 48 (preferably 6 to 24), that is, the pitch angle 1
20 to 7.5 ° (preferably 60 to 15 °).

The projecting direction of the fins 14 formed on the outer peripheral surface is not necessarily the normal direction as shown in the figure, but is slightly right or left from the normal direction so that the rotation direction is one direction. It may be formed so as to be inclined (10 to 45 ° with respect to the normal line) (see a two-dot chain line in FIG. 2).

From the viewpoint of increasing the efficiency of attaching microorganisms per unit volume in the cylindrical body, it is desirable to form the fins 16 on the inner peripheral surface side of the cylindrical body. However, the fins 16 on the inner peripheral surface side do not have the function of generating the rotation of the cylindrical body due to the water flow, and conversely, if the number of fins is too large, the water in the hollow portion 13 of the cylindrical body will be reduced. When the flow rate is too low, it becomes difficult for surplus microorganisms and the like adhering to the hollow portion 13 of the cylindrical body to be separated during the submerged swirling and floating (flowing). Therefore, the number of the inner peripheral surface side fins 16 is usually smaller than that of the outer peripheral surface side fins 14. That is, the number of the fins 14 is 3 to 24 (preferably 3 to 12).

Further, a support plate portion 20 having a Y-shaped cross section is formed inside so as to prevent the cylindrical body 12 from being closed during handling. When the tubular body 12 is formed of a soft resin such as a thermoplastic elastomer, it is preferable that the tubular body 12 be provided. The Y-shape is used to form an intersection and increase the efficiency of microorganism attachment. The support plate may be one in diameter, or one end may be a free end.

Here, the specific gravity of the cylindrical body is not particularly limited, but is 0.8 to 1.0, preferably 0.85 to 0.9.
A value of 5 is desirable from the viewpoint of the revolving floating property of the microorganism carrier element (tubular body) 12 and a reduction in stirring power.

The material for forming the carrier element 12 may be foamed ceramics or other composite materials as long as the specific gravity can be adjusted within the above range, but is usually formed of a plastic material containing a thermoplastic elastomer. Specifically, hard / soft polyethylene, polypropylene, olefin-based thermoplastic elastomer, and the like can be suitably used.

In particular, the use of a soft plastic material containing a thermoplastic elastomer makes it difficult for the carrier elements 12 themselves to be damaged by interference with each other or between the carrier element 12 and other members. It is desirable to bend when circulating and floating in the water flow, and to be able to expect exfoliation of surplus microorganisms in the hollow portion 13 of the cylindrical body.

The production method is performed by extruding into a cylindrical shape, cutting, or by injection molding using a multi-cavity mold. At this time, from the viewpoint of weather resistance and strength,
It is desirable to add a reinforcing filler such as carbon black, an antioxidant, and the like.

(2) Next, a wastewater treatment method using the microorganism carrier 12 will be described.

For example, a case where high-concentration sewage is treated according to the flow shown in FIG. 5 will be described as an example.

That is, the raw water (sewage) flowing into the flow rate adjusting tank 22 is caused to flow into the fluidizing tank 24, and the treated water subjected to the microbial chemical treatment in the fluidizing tank 24 is separated and discharged in the sedimentation tank 26.

The fluid tank 24 is charged with a large number of the microorganism carrier elements 12 of the present invention to form a microorganism carrier. Here, when the microbial carrier element (cylindrical body) 12 having a carrier diameter of 10 mm and a carrier length of 10 mm is used, the charge amount is, for example, about 250,000 packing density / m ³ . At this time, the specific surface area is about 1000 m ² / m ³ , and the porosity is about 90%.
Aerobic bacteria are carried on this microorganism carrier.

In the fluidized tank 24, the microorganism carrier 12 is swirled and floated in the fluidized tank 22 by forced aeration from below by an air diffuser (consisting of a blower 28 and an air diffuser 30). Promotes the purification of sewage. The large number of carrier elements 12 carrying the microorganisms purify the whole from the bottom to the top while swirling and floating (flowing) in water. At this time, the carrier element (cylindrical body) 12 circulates while the fins 14 formed on the outer periphery rotate by receiving the water flow. The surplus microorganisms attached to the fins 14 are constantly peeled off, so that surplus microorganisms do not accumulate between the fins 14. Therefore,
It is not necessary to wash periodically as in the case of the above-mentioned spherical microorganism carrier.

[0039]

According to the present invention, the microorganism carrier element of the present invention and the fluidized bed water treatment apparatus using the same to form a microorganism carrier have a structure in which the microorganism carrier element has a large number of fins at least on the outer peripheral surface as described above. Since it is a cylindrical body, the following operations and effects are achieved.

The specific surface area per volume of the carrier element is large, the area where microorganisms can be implanted is large, and an increase in water treatment capacity can be expected. Further, since the cylindrical body also rotates by itself when the microorganism carrier element is swirled and floated (flowed) in water, surplus microorganisms adhering to the fins are constantly peeled off and surplus microorganisms do not accumulate. Therefore, it is not necessary to wash periodically as in the case of the above-mentioned spherical microorganism carrier.

Further, the microbial carrier element of the present invention is very small, is not bulky when transported or the like, and can be usually formed of a soft plastic material when transported. And even if they come into contact with each other, the risk of breakage is smaller than that of a spherical microorganism carrier.

Furthermore, the microbial carrier element can be easily manufactured by simply cutting it after extruding it into a cylindrical shape, or simply by injection molding using a multi-cavity mold. Therefore, as compared with the above-mentioned microbial carrier consisting of spheres, several molds for production are not required, and the number of production steps can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a microorganism carrier element of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a plan view showing one embodiment of the microorganism carrier element of the present invention.

FIG. 4 is a model sectional view of a fluidized-bed water treatment apparatus to which the microorganism carrier of the present invention is applied.

FIG. 5 is a flowchart of sewage treatment incorporating a fluidized-bed water treatment apparatus.

[Explanation of symbols]

 Reference Signs List 12 microorganism carrier element (finned cylindrical body) 14 fin (outer peripheral surface side) 16 fin (inner peripheral surface side) 18 side surface of rectangular cylindrical body 22 flow control tank 24 fluidizing tank 26 sedimentation tank 28 diffuser 30 blower

Claims (10)

[Claims] 1. A carrier element for forming a microbial carrier by introducing a large number of fins radially into a fluidized bed type water treatment tank for biochemically treating sewage. A microbial carrier element for water treatment, which is in the form of a solid. 2. The microbial carrier element for water treatment according to claim 1, wherein the cylindrical body includes a plurality of the fins on the inner peripheral surface side. 3. The fin on the outer peripheral surface side of the cylindrical body,
2. The microbial carrier element for water treatment according to claim 1, wherein rotation of the cylindrical body is positively generated by the water flow. 4. The microbial carrier element for water treatment according to claim 1, wherein the specific gravity of the cylindrical body is 0.8 to 1.0. 5. The microbial carrier element for water treatment according to claim 4, wherein the cylindrical body is a molded article of a polyolefin resin. 6. A fluidized-bed water treatment apparatus for biochemically treating sewage, comprising: a water treatment tank; a microbial carrier comprising a plurality of carrier elements charged into the water treatment tank; And a diffuser for stirring and circulating water in water, wherein the carrier element is a cylindrical body having a large number of fins at least on the outer peripheral surface side in a radial manner. 7. The fluidized-bed water treatment apparatus according to claim 6, wherein the cylindrical body includes a plurality of the fins also on an inner peripheral surface side. 8. The fin on the outer peripheral surface side of the cylindrical body,
The fluidized bed type water treatment apparatus according to claim 6, wherein rotation of the cylindrical body is positively generated by the water flow. 9. The fluidized-bed water treatment apparatus according to claim 6, wherein the specific gravity of the cylindrical body is 0.8 to 1.0. 10. The microbial carrier element for water treatment according to claim 9, wherein the tubular body is a molded article of a polyolefin resin.