JP2001300573A - Microorganism carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microorganism carrier which has durability and excellent microorganism implantability, lessens the laboriousness of operation and can reduce a running cost. SOLUTION: The microorganism carrier consists of structures in which loops are formed by continuous filaments consisting of thermoplastic resins and the greater part of the each others contact parts are joined. The filaments have hollow parts and the relationship between the hollow rate (HU) of the hollow parts and the sp. gr. (PSG) of the thermoplastic resins satisfies 1.00>=PSG (1-HU).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microorganism carrier for purifying dirty water by propagation of microorganisms without causing environmental pollution. Further, the present invention relates to a microorganism carrier optimal for a purification device using an aeration tank.

[0002]

2. Description of the Related Art As disclosed in Japanese Patent Application Laid-Open No. 51-59451, a method is disclosed in which a net is installed in an aeration tank and microorganisms are carried on the net and propagated to purify sewage. . In this method, a large amount of labor is required to form a structure in which a large number of nets are laminated, and there is a problem of cost. In addition, there is a problem that the structure is heavy and handling properties are poor. Japanese Patent Application Laid-Open No. 53-125359 discloses the use of a nonwoven fabric having a network structure in which fibers such as nylon, vinylidene chloride, and vinyl chloride are curled, formed into a web or mat, and thermally bonded, as a microorganism carrier. Have been. However, when a web-like or mat-like material is thermally bonded, the bonding strength is poor, and when the material is purified at high speed, there is a problem that the material is broken in the aeration tank. Japanese Patent Application Laid-Open No. Hei 6-190386 discloses a linear shape of polypropylene and polyethylene having a small amount of contaminants (diameter of 6
mm, 3 mm in length) in an irregular shape, and the linear surface is exposed to the surface by kneading one kind of carbon black, metal powder, barium sulfate, calcium sulfate, calcium carbonate, etc. Microorganism carrier obtained by adhering one kind of carbon black, metal powder, barium sulfate, calcium sulfate, calcium carbonate, etc. to a microorganism carrier or polypropylene network, which is compared with a polypropylene network and a vinylidene chloride mat. A microorganism carrier for water purification is disclosed. When a large agitation force acts on this carrier, such as in an aeration tank, there is a problem that shape retention is poor and this is not preferable. Japanese Patent Application Laid-Open No. 9-220587 discloses a reticulated flat cylindrical body for a flow-type purifying apparatus having a stirring action. This reticulated flat cylindrical body is made of polyethylene or polypropylene having a wire diameter of 0.5 to 2 mm and a cylindrical body diameter of 6 to 30 mm.
It is a microorganism carrier cut into a tube length of 6 to 30 mm.
This microorganism carrier is obtained by extrusion molding into a reticulated tubular body, flattening and cutting, but because the wire diameter is large and the length of the filament is short, the surface area of the filament in the carrier is reduced and the microorganism carrier is reduced. There is a problem that the landing amount is restricted.

As a microorganism carrier for a fluid-type water purification treatment apparatus, a method for improving the purification efficiency by miniaturization to enhance the establishment of contact with microorganisms, for example, JP-A-9-28528
In Japanese Patent Publication No. 7, the spherical diameter of the hollow portion connected to the outside is 1.5 to
A 6 mm hollow sphere has been proposed. The carrier is intended to simultaneously implant aerobic microorganisms and anaerobic microorganisms to improve purification efficiency. In this proposal, it is complicated to prepare a microorganism carrier, and it is necessary to separate and recover the carrier to regenerate or additionally replenish the carrier, which causes problems of complicated operation and increased running cost. Also, Japanese Patent Application Laid-Open
Japanese Patent Publication No. 174989 proposes a hollow tubular plastic microorganism carrier having an outer shape and a tube length of 10 mm or less. The microorganism carrier carries microorganisms in the tube to aerate aerobic microorganisms with air and anaerobic microorganisms with an inert gas to improve purification efficiency. Also in this proposal, it is necessary to separate and recover the microorganism carrier and regenerate or additionally replenish it. Further, it is necessary to change the type of the aeration gas, and the operation becomes complicated and the running cost increases.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and provides a microorganism carrier which is durable, has excellent microorganism-implantability, reduces the complexity of operation, and can reduce running costs. The purpose is to do. It is a further object of the present invention to provide a microorganism carrier optimal for a microorganism carrier for a fluidized water purification treatment apparatus.

[0005]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and as a result, continuous filaments having a hollow cross section made of a thermoplastic resin have formed loops, and have been in contact with each other. The present invention has been achieved by using a structure in which most of the parts are joined.

That is, the invention according to claim 1 of the present invention relates to a structure in which continuous filaments having a hollow cross section made of a thermoplastic resin form a loop and most of their contact portions are joined. The filament has a hollow portion, and the hollow ratio of the hollow portion (H
U) and the specific gravity (PSG) of the thermoplastic resin is 1.00.
A microorganism carrier characterized by satisfying ≧ PSG (1-HU).

According to a second aspect of the present invention, in the microorganism carrier according to the first aspect, the thermoplastic resin is a thermoplastic elastic resin.

According to a third aspect of the present invention, there is provided the microorganism carrier according to any one of the first and second aspects, wherein the wire diameter is 0.0
5 mm or more and less than 1 mm, the apparent density of the structure is 0.01 to
0.3 g / cm ³ .

According to a fourth aspect of the present invention, in the microorganism carrier according to any one of the first and second aspects, the cut end of the hollow portion is closed.

According to a fifth aspect of the present invention, in any one of the first to second aspects of the present invention, the outer peripheral portion is joined.

In a preferred embodiment of the present invention, the thermoplastic resin forming the microorganism carrier is one that passes voluntary standards for food containers made of synthetic resin such as polyolefin.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic resin in the present invention refers to a resin having thermoplasticity and capable of being melt-spun. For example, polyester, polyamide, polyolefin, polyurethane, polyvinyl alcohol, polyvinylidene chloride, polyvinyl chloride and the like can be exemplified. In the present invention, it is preferable to use one having a glass transition temperature of at least 40 ° C. or higher. For example, in polyester,
Polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycyclohexylene dimethylene terephthalate (PCHDT), polycyclohexylene dimethylene naphthalate (PCHDN), polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), polyarylate and the like, and copolymerized polyesters thereof. Polyamides include polycaprolactam (NY6), polyhexamethylene adipamide (NY66), and polyhexamethylene sebacamide (N
Y610) and their copolymerized polyamides. Polyolefins include polyethylene (PE),
Polypropylene (PP), Polybutene-1 (PB-
1) and their copolymerized polyolefins.

As the thermoplastic resin used in the present invention, for example, when used in an individual septic tank in a hotel or the like, polyester and polyamide, olefins having a high glass transition point, which have good heat resistance in consideration of inflow of boiling water, etc. Are particularly preferred. Furthermore, it is most preferable that the composition does not contain a chemical or the like that causes environmental pollution and passes the voluntary standards for food containers made of synthetic resin such as polyolefin.

The thermoplastic elastic resin in the present invention is a polyether-based glycol, polyester-based glycol, polycarbonate-based glycol or long-chain hydrocarbon having a molecular weight of 300 to 5000 as a soft segment. Polyester-based elastomer, polyamide-based elastomer, polyurethane-based elastomer, which is obtained by block-copolymerizing an olefinic compound having a carboxylic acid or a hydroxyl group at a terminal.
And polyolefin-based elastomers. By using a thermoplastic elastic resin, regeneration becomes possible by re-melting, so that recycling becomes easy.

For example, as a polyester elastomer, a thermoplastic polyester is used as a hard segment,
Examples thereof include a polyester ether block copolymer having a polyalkylenediol as a soft segment and a polyester ester block copolymer having an aliphatic polyester as a soft segment. Polyester d
More specific examples of terblock copolymers include terephthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl
Aromatic dicarboxylic acids such as -4.4'-dicarboxylic acid;
An alicyclic dicarboxylic acid such as 4-cyclohexanedicarboxylic acid, an aliphatic dicarboxylic acid such as succinic acid, adipic acid, sebacic acid dimer acid, or at least one dicarboxylic acid selected from ester-forming derivatives thereof; ,
Aliphatic diols such as 1,4-butanediol, ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, and 1,1-cyclohexanediol Methanol,
Alicyclic di- such as 1,4-cyclohexanedimethanol
Or at least one diol component selected from ester-forming derivatives thereof, and polyethylene glycol, polypropylene glycol, polytetramethylene glycol having an average molecular weight of about 300 to 5,000.
And a triblock copolymer comprising at least one of polyalkylenediols such as glycols and ethylene glycol-propylene oxide copolymers.

As the polyester ester block copolymer, a ternary block copolymer composed of at least one of the above dicarboxylic acids and at least one of diols and polyester diols such as polylactone having an average molecular weight of about 300 to 5,000 is used. It is united. In consideration of thermal adhesion, hydrolysis resistance, stretchability, heat resistance, etc., terephthalic acid or naphthalene-2,6-dicarboxylic acid as a dicarboxylic acid, and 1,4-butanedioxide as a diol component. As the polyalkylenediol, a triblock copolymer of polytetramethylene glycol or a polyesterdiol as a triblock copolymer of polylactone is particularly preferable. In a special case, those incorporating a polysiloxane-based soft segment can also be used. Also,
The thermoplastic elastomer resin of the present invention also includes those obtained by blending the above elastomer with a non-elastomer component, copolymerized product, and polyolefin-based component made into a soft segment.

[0017] As the polyamide-based elastomer,
Nylon 6, nylon 66, nylon 6 for the do segment
10, nylon 612, nylon 11, nylon 12, etc. and their copolymerized nylon as a skeleton, and the soft segment includes polyethylene glycol, polypropylene glycol, polytetramethylene glycol having an average molecular weight of about 300 to 5000. A block copolymer composed of at least one of polyalkylenediols such as a glycol composed of an ethylene oxide-propylene oxide copolymer may be used alone or as a mixture of two or more. Further, those in which a non-elastomer component is blended or copolymerized can be used in the present invention.

As the polyurethane elastomer, (A) a number average molecular weight of 1 in the presence or absence of a usual solvent (dimethylformamide, dimethylacetamide, etc.)
(B) a polyisocyanate having an organic diisocyanate as a main component obtained by reacting a polyether and / or polyester having a hydroxyl group at a terminal of 000 to 6000 with an isocyanate group at both terminals; A typical example is a polyurethane elastomer which is chain-extended by a polyamine containing a diamine as a main component. The polyester and polyethers (A) have an average molecular weight of about 1000 to 6000, preferably 1300 to 5000.
Polybutylene adipate copolymer polyester or polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyalkylene diols such as glycols composed of ethylene oxide-propylene oxide copolymers are preferred, As the polyisocyanate (B), a conventionally known polyisocyanate can be used, but an isocyanate mainly composed of diphenylmethane-4,4'-diisocyanate is used, and if necessary, a conventionally known triisocyanate is used.ト may be used in a small amount. As the polyamine (C), ethylenediamine,
Known diamines such as 1,2-propylenediamine may be mainly used, and a small amount of triamine or tetraamine may be used in combination as needed. These polyurethane elastomers may be used alone or in combination of two or more.

The melting point of the thermoplastic elastic resin of the present invention is preferably 140 ° C. or higher which can maintain the heat resistance and durability.
It is more preferable to use one having a temperature of 0 ° C. or higher because the heat resistance and durability are improved. In addition, durability can be improved by adding an antioxidant, a light stabilizer, or the like, if necessary. Then
Most preferably, they pass the voluntary standards for food containers made of synthetic resin such as polyolefin.

The content of the soft segment of the thermoplastic elastic resin constituting the component for imparting elasticity, impact absorption function and durability as the microorganism carrier as the object of the present invention is preferably 10% by weight or more and 70% by weight or less. And more preferably 15% by weight or more and 60% by weight or less.

In the case of the component comprising the thermoplastic elastic resin constituting the microorganism carrier of the present invention, it is preferred that the melting curve measured by a differential scanning calorimeter has an endothermic peak below the melting point. Those having an endothermic peak at or below the melting point have significantly improved elongation recoverability compared to those having no endothermic peak, so that impact absorption and shape retention are improved.

For example, preferred polyester-based thermoplastic resins of the present invention include those containing 90 mol% or more of terephthalic acid or naphthalene-2,6-dicarboxylic acid having rigidity in the acid component of the hard segment. Preferably, the content of terephthalic acid or naphthalene-2,6-dicarboxylic acid is 95 mol% or more, particularly preferably 100 mol%, after transesterification of the glycol component, polymerization to the required degree of polymerization, and then polyalkylene As the diol, polytetramethylene glycol having an average molecular weight of preferably 500 to 5,000, particularly preferably 1,000 to 3,000 is preferably 15 to 70% by weight, more preferably 30 to 60% by weight. When copolymerized, terephthalic acid or naphthalene-2.6-having rigidity in the acid component of the hard segment The carboxylic acid content is often a hard -
The crystallinity of the dosegment is improved, plastic deformation is less likely to occur, and the heat resistance and sag resistance is improved. improves.

Annealing after imparting a compressive strain further improves the elongation recoverability. Those treated in such a manner more clearly show an endothermic peak in a melting curve measured by a differential scanning calorimeter at a temperature from room temperature to the melting point. When no annealing is performed, an endothermic peak does not appear in the melting curve from room temperature to the melting point. By analogy with this,
By annealing, the hard segments are rearranged,
It is conceivable that pseudo-crystallization-like cross-linking points were formed and the stretch recovery was improved. In the present invention, this process is defined as a pseudo crystallization process. This pseudo-crystallization effect is also effective for polyamide-based elastic resins and polyurethane-based elastic resins.

The reason why the present invention uses a thermoplastic resin is as follows.
By melt spinning, the continuous filaments of the hollow cross section form a loop, which is essential for directly forming a structure in which most of the contact portions of each other are joined. Thus, the structure can be efficiently obtained, and thus can be provided at a low cost. By forming a structure in which continuous filaments having a hollow cross section form a loop and most of the contact portions are joined to each other, the surface area of the filaments can be increased, so that implantation of microorganisms can be increased. In addition, the hollow cross section increases the surface area because the wire diameter increases with the same mass.

Further, when used as a microorganism carrier for a purification apparatus having a flow-type aeration tank, it is necessary to have at least the same apparent specific gravity as water in order to achieve good circulation. That is, the filament has a hollow portion, and the hollow ratio (H
U) and the specific gravity (PSG) of the thermoplastic resin is 1.0
This can be achieved by satisfying 0 ≧ PSG (1-HU). Preferably, 0.95 ≧ PSG (1-HU), and more preferably, 0.92 ≧ PSG (1-HU).

In the present invention, the hollow ratio of the filament is preferably 0.15 or more and 0.5 or less, more preferably 0.25 or more and 0.4 or less. If the hollow ratio is too small, the above 1.00 ≧ PSG (1-HU) depending on the material used.
May not be satisfied in some cases. If the hollow ratio is too large, the filaments may be crushed, which is not preferable.

In the most preferred embodiment of the present invention,
By closing the cut end of the hollow portion, it is possible to prevent liquid or microorganisms from entering the hollow portion, and it is possible to keep the apparent specific gravity of the structure at least equal to that of water for a long period of time. When used by sinking, it is preferable to use an anaerobic microorganism or the like injected into the hollow portion without closing the cut end.

The preferable diameter of the filament of the present invention is 0.05 mm.
And less than 1 mm. If the wire diameter is too small, the joining of the loops may be insufficient, and the shape may be unfavorably deteriorated due to softness. If the wire diameter is too large, the surface area of the filament per apparent density is reduced, and the amount of microorganisms to be implanted is reduced. More preferable wire diameter is 0.1 mm or more and 0.8 mm, most preferably 0.2 mm or more.
mm or more and 0.5 mm or less.

The preferred apparent density of the microorganism carrier of the present invention is from 0.01 g / cm ^{3 to} 0.3 g / cm ³ . If the apparent density is too low, the shape retention is inferior, and the area where the microorganisms can be implanted decreases with a decrease in the number of components, which is not preferable. If the apparent density is too high, the number of components will increase and the number of joints will increase and the shape retention will improve, but the decrease in voids will limit the growth area of microorganisms and at the same time increase the flow resistance of flowing water. It is not preferable because the aeration effect is lowered. More preferable apparent density of the present invention is 0.02 g / cm ³ or more and 0.25 g / cm ³ or less,
Most preferably, 0.03 g / cm ³ or more and 0.20 g / c
m ³ or less.

When used in a fluidized purifier, the outer peripheral portion of the microorganism carrier is joined, so that a large impact force due to agitation or aeration or fraying or peeling of the filament due to collision of the microorganism carrier is prevented, and the form is maintained. This is a preferred embodiment of the present invention because the properties are further improved.

In one embodiment of the microorganism carrier of the present invention, the thermoplastic resin is a thermoplastic elastic resin. By using a thermoplastic elastic resin, the rubber elasticity of the thermoplastic elastic resin expands and contracts even if deformed by stress, and recovers its original shape. Is particularly preferred since it significantly improves

In the present invention, it is 199 to pass the voluntary standard for food containers made of synthetic resin such as polyolefin.
It refers to a composition conforming to the contents described in the third edition limited edition of the voluntary standards for food containers made of synthetic resins such as polyolefins issued by the Polyolefin Sanitation Council in March 1995. As an example of the most preferred embodiment of the present invention, purified water discharged from rivers, lakes, marshes, harbors, etc. is obtained by using a microorganism carrier using a composition that passes voluntary standards for food containers made of synthetic resin such as polyolefin. It is a microbial carrier with good environmental compatibility because it does not cause secondary pollution.

Next, an example of the production method of the present invention will be described. A thermoplastic resin or a thermoplastic elastic resin (preferably, a composition that passes the voluntary standards for food containers made of synthetic resin such as polyolefin when additives are contained) from a multi-row nozzle having a plurality of hollow section forming orifices It is distributed to each nozzle orifice and discharged downward from the nozzle at a melting temperature higher than the melting point of the thermoplastic resin by 10 ° C. or more and lower than 120 ° C., and is brought into contact with each other in a molten state to be fused to form a three-dimensional structure. After being formed, it is sandwiched by a take-off device, cooled in a cooling tank, and then cut into a desired length to obtain a sheet-like net-like structure. A method for forming a hollow by injecting gas immediately before the orifice inlet, or a method for forming a hollow in the hollow cross-section forming orifice, holding the cross section of the orifice with a C-shaped one-bridge or triple-bridge, and slitting the resin discharge hole It is possible to employ a method in which a gas is sucked immediately after the molten wire is discharged by using an orifice held in a bridge and held by a bridge, and then joined by a ballast effect.

The hollow ratio is calculated according to the above relational expression 1.00 ≧ PSG (1
−HU). The wire diameter is determined by the balance between the shape of the orifice, the discharge amount of a single hole, the melt viscosity, and the distance between the take-off points. When the orifice diameter is reduced, the diameter tends to be small, but when the discharge amount is large, the diameter becomes large. If the amount is too small, it is easy to cool and the joining of the contacts may be insufficient, which is an unfavorable condition. The lower the melt viscosity, the easier it is to make it thinner by falling under its own weight, but it is necessary to maintain a molecular weight capable of maintaining the strength as a microorganism carrier. The longer the take-up point distance from the orifice, the thinner. However, if the length is too long, the cooling is excessive, and the formation of the network structure becomes insufficient. Therefore, it is necessary to set an optimum take-off point distance.

In the present invention, it can be used as a microorganism carrier in a sheet form as it is. Even when the sheet is used as it is, when a thermoplastic elastic resin is used as the material, it is preferable to perform a pseudo-crystallization treatment as described above.

When used in an apparatus which receives a large impact, such as an aeration tank for performing a flow type high-speed purification treatment, an arbitrary shape (for example, 30 mm to 50 mm square or φ 30 mm to φ
The hollow cut end is closed and the outer periphery is joined by means of hot pressing with a mold, punching and cutting, or using an ultrasonic welder so as to form a 50 mm circular or spherical shape ( It is preferable that the reinforcing effect is large) for the above-mentioned reason.

If use and maintenance become easy even when a large impact is not received, it can be cut to an arbitrary size and used without closing the cut end.

The microbial carrier thus obtained supports and proliferates the microorganism in the structure composed of the striatum, thereby purifying the wastewater efficiently.

[0039]

The present invention will be described in detail with reference to the following examples. However, the present invention is not limited by these examples. The evaluation in the examples was performed by the following method. (A) Specific gravity (PSG) A section is vacuum-defoamed in a solvent used for a density gradient tube, and measured at 40 ° C. using a density gradient tube to determine specific gravity (PSG).

(B) Hollowness ratio (HU) Each linear portion is cut out of ten samples, embedded in acrylic resin, the cross section is cut out, and a slice is prepared to obtain a cross-sectional photograph. The sectional area (Si) and the cross-sectional area (Shu) of each part are obtained from the cross-sectional photographs of each part, and the hollow ratio is calculated by the following equation. Hollow ratio (HU) = [1 / n {(Shu)] / [1 / n}
(Si)]

(C) Wire diameter (D) The diameter (unit: mm) is determined from the above cross-sectional photograph, and is defined as the wire diameter. (D) Apparent density (1) Large sample A sample is cut into a size of 15 cm x 15 cm, the height of four places is measured, the volume is determined, and the weight of the sample is indicated by a value obtained by reducing the volume by the volume. (Average value of n = 4) (2) Small sample The circumscribed volume of the whole sample is determined, and the weight of the whole sample is expressed by a value described by volume. (Average value of n = 4)

(E) Water quality evaluation The following items were measured in accordance with the JIS method. Turbidity (JIS
K010), BOD (JIS K0102.21)
・ Based on 32.3)

(F) Microorganism adhesion state Grade evaluation of the adhesion state of microorganisms by visual observation Grade 5: Very large. Grade 4: Many. Level 3: Normal. Grade 2: Less. Grade 1: Very little adhesion. Grade 0: No adhesion.

(G) Melting point (Tm) and endothermic peak (Tαcr) at or below the melting point Using a TA50, DSC50 type differential thermal analyzer manufactured by Shimadzu Corporation at a heating rate of 20 ° C./min. Endothermic peak (Tm and Tαcr) temperatures were determined.

(H) Occlusion and Joining The sample is visually judged to determine that the hollow section is closed when the cut end of the hollow section is crushed and joined. It is judged whether or not the outer fibers are joined by checking whether or not the outer fibers are joined by pulling the joined fibers by hand.

Example 1 Dimethyl terephthalate (DMT) or dimethyl naphthalate (DM) was used as a polyester elastomer.
N) and 1,4-butanediol (1.4BD) were charged with a small amount of a catalyst, transesterified by a conventional method, polytetramethylene glycol (PTMG) was added, and the mixture was subjected to polycondensation at elevated temperature and reduced pressure. Polyetherester block copolymerized elastomer was produced, and then 0.2% of Adeka Stab AO330 manufactured by Asahi Denka Kogyo was added and mixed as an antioxidant, kneaded, pelletized, and vacuum-dried at 50 ° C. for 48 hours. Table 1 shows the formulations of the thermoplastic elastomer resin raw materials.

[0047]

[Table 1]

A 50 mm wide, 700 mm long nozzle has an orifice hole formed in a staggered arrangement with a hole pitch of 5 mm in the width direction on the effective surface of the nozzle. The nozzle has an outer diameter of 2 mm, an inner diameter of 1.6 mm, and a hollow cross section of a triple bridge. (1546 holes), the obtained thermoplastic elastic resin raw material (A-1) was discharged at a melt spinning temperature of 240 ° C. at a single hole discharge rate of 1.98 g / min. Cooling water is provided below, and a pair of take-off conveyors are arranged in parallel at 45 mm intervals with a stainless steel endless net having a width of 1000 mm so as to partially emerge above the water surface. A three-dimensional net-like structure is formed while forming a loop and joining the contact portions, and both sides of the molten net are sandwiched between take-up conveyors at a speed of 2 m / min.
After being drawn into the cooling water at ℃ and solidified by flattening both sides, the sheet-like structure made of thermoplastic elastic resin obtained by cutting into 2 m has a hollow cross-section having a triangular conical shape with a hollow ratio of 0.38, It was formed with a filament having a wire diameter of 0.4 mm, and the average apparent density was 0.05 g / cm ³ .

Next, the structure B1 of the present invention was obtained by pseudo-crystallization treatment with hot air at 105 ° C. for 20 minutes. Next, both sides of the back and front sides are sandwiched between cylinders having an outer diameter of 40 mm and an inner diameter of 34 mm, and are heated to about 100 kg / cm ² at a hot press temperature of 200 ° C.
After cooling by compressing the outer periphery with the pressure of, the cut end of the oval spherical hollow portion punched out with φ40 mm was closed, and the microorganism carrier C1 having the outer periphery joined was obtained. The apparent density obtained from the projected image and the weight of the obtained microorganism carrier C1 is 0.16.
g / cm ³ . The specific gravity of 1.18 × (1−hollow ratio 0.38) is 0.73 or less, which satisfies the requirements of the present invention.

100 microbial carriers C1 are put into an aeration tank having a capacity of 18 liters, aerobic microorganisms are added as seed microorganisms, and organic matter, ammonia nitrogen, nitrite nitrogen and suspension are mainly added. Model wastewater as a component was supplied at a BOD load of 30 mg / liter. The BOD concentration and turbidity of the treated water separated through the aeration tank and the precipitation tank were measured.
Table 2 shows the measurement results of the water purification function. 45 days later, as a result of taking out the microorganism carrier and evaluating the attached state of the microorganism,
It was grade 3. The microorganism carrier holding the collected microorganisms was easily washed with a water stream.

[0051]

[Table 2]

Example 2 Using the polymer of Experiment No. 2, the melt spinning temperature was adjusted to 2
The microorganism carrier C2 was obtained under the same conditions except that the temperature was set to 50 ° C. and the hot press temperature was set to 210 ° C. The obtained microorganism carrier C2 had a hollow ratio of 0.41, a wire diameter of 0.39 mm, an apparent density of 0.14 g / cm ³ , and a specific gravity (1-hollow ratio) of 0.72, satisfying the requirements of the present invention. To satisfy. Table 2 shows the results of evaluating the water purification function in the same manner as in Example 1 using the microorganism carrier C2. After 45 days, the microorganism carrier was taken out, and the state of adhesion of the microorganisms was evaluated. The microorganism carrier holding the collected microorganisms was easily washed with a water stream.

COMPARATIVE EXAMPLE 1 At a spinning temperature of 200 ° C., a solid filament of 0.4 mm in diameter composed of a linear low-density polyethylene of MI50 at the sheath and polypropylene of MI50 at the core was obtained. After applying a mechanical crimp to the filament, the filament is cut to 150 mm to form a staple, and then spread and laminated and compressed, and heat-treated with hot air at 140 ° C. for 15 minutes to obtain an apparent density of 140 kg / m ³ , A sheet C3 having a thickness of 4 cm was obtained. 4c of the obtained sheet C3
Table 2 shows the results of evaluation of the water purification function in the same manner as in Example 1 by cutting into m-shaped dice. The microorganism carrier C3 was destroyed after 30 days, and the number of carriers was gradually reduced. 45 days later, the remaining microorganism carrier C3 was taken out and the state of adherence of microorganisms was evaluated.
It was class. Moreover, the state of adhesion of the microorganisms to the broken carrier streaks was grade 0 to grade 1. In addition, there were few microbial carriers holding the recovered microbes that could be broken down and reused even by washing with a water stream.

As is clear from Table 2, Examples 1 and 2 show a better water purification function than Comparative Example 2 even at the initial stage, and show that this good water purification function is maintained for a long time. Comparative Example 1 also shows a relatively good water purification function at an early stage, although it is inferior to the embodiment, but the microbial carrier is destroyed after 30 days, and the water purification function gradually decreases. . In addition, it has been clarified that the microorganism carrier can be easily reused in the present invention.

In the first and second embodiments, the difference in the water purification function at the initial stage is a structure in which the continuous filaments form a loop, most of the contact portions are joined, and the surface area is large due to the hollow cross section. It is presumed that the microorganism carrying ability was excellent. In addition, the water purification function for a long time was maintained because the surroundings were firmly joined even if a large impact was caused by aeration, and the microbial carrier was destroyed by absorbing the impact force of the elastic resin. It was presumed that the continuous filaments formed a loop, and most of the contacting parts were joined together. Is done.

[0056]

According to the present invention, there is provided a structure in which a continuous filament forms a loop, and most of the contact portions are joined to each other.
Due to the large surface area of the hollow cross section, the microorganism carrying capacity is excellent, and it is lighter than water. Furthermore, even when used for a long period of time, the contact between the carriers and the water flow through the water flow by aeration are good, and the unnecessary sludge that has lost its activity is easily dropped off appropriately, and the growth of microorganisms attached to the carrier is increased. Because of the structure that can keep the environment well, it can keep the water purification function for a long time.
In particular, in the case where the material is a thermoplastic elastic resin, which is a preferred embodiment of the present invention, the impact force due to aeration is absorbed to make it difficult to be broken, and furthermore, the effect of improving the shape retention by joining the outer periphery is further improved. Together with this, the water purification function for a long time can be maintained. Furthermore, since lightness can be maintained for a long time by closing the hollow cut end, good purification efficiency can be maintained for a long time. In addition, since it has good durability, can be used for a long time, and can be easily washed after use and can be reused, the complexity of operation can be reduced and the running cost can be reduced. Furthermore, as a preferred embodiment of the present invention, by using a microorganism carrier using a composition that passes voluntary standards for food containers made of synthetic resin such as polyolefin, purified water discharged is river,
Since it does not cause secondary pollution to lakes, marshes, ports and the like, it is possible to provide a microorganism carrier having good environmental compatibility.

Claims (5)

[Claims] In a structure in which a continuous filament made of a thermoplastic resin forms a loop and most of the contact portions are joined to each other, the filament has a hollow portion, and the hollow ratio of the hollow portion ( H
U) and the specific gravity (PSG) of the thermoplastic resin is 1.00.
A microorganism carrier which satisfies ≧ PSG (1-HU). 2. The microorganism carrier according to claim 1, wherein the thermoplastic resin is a thermoplastic elastic resin. 3. The microorganism carrier according to claim 1, wherein the wire diameter is 0.05 mm or more and less than 1 mm, and the apparent density of the structure is 0.01 to 0.3 g / cm ³ . 4. The microorganism carrier according to claim 1, wherein the cut end of the hollow portion is closed. 5. The microorganism carrier according to claim 1, wherein an outer peripheral portion is joined.