JP2001205288A - Carrier for water treatment, its production method, and apparatus for water treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carrier for water treatment which has good fluidity, is excellent in durability, and can be produced efficiently, a method for producing the carrier, and an apparatus for water treatment using the carrier. SOLUTION: The carrier for water treatment is formed from a porous molding by melt-molding a hydrophilic thermoplastic resin or a mixture of the resin and one or more kinds of other thermoplastic resins together with a foaming agent. The carrier can be produced continuously in an optional shape and in a large amount by melt-molding. The specific gravity of the carrier can be adjusted by selecting its porosity by regulating the amount of the foaming agent to be added to improve its fluidity. Moreover, the affinity with microorganisms can be enhanced to improve the adhesion of microorganisms and their propagation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a water treatment carrier used for various water treatments using microorganisms, a method for producing the water treatment carrier, and a water treatment apparatus using the water treatment carrier. About.

[0002]

2. Description of the Related Art Conventionally, in water treatment such as wastewater treatment using microorganisms, for example, a water treatment carrier comprising a synthetic resin molded product as a fluidized bed in a water treatment tank such as an anaerobic tank or an aerobic tank. Has been turned on. The carrier for water treatment performs water treatment by adhering microorganisms in the tank and growing the adhered microorganisms.
As such a carrier for water treatment, for example, a molded product of a polyethylene resin or a polypropylene resin is used.

[0003]

However, since the specific gravity of such a polyethylene resin or a polypropylene resin is 1.0 or less, if the molded product is used as it is in a fluidized bed, it will rise from water. For example, a filler such as calcium carbonate or barium sulfate is blended to adjust the specific gravity to improve the fluidity.

However, when fillers such as calcium carbonate and barium sulfate are blended, there is a problem that mechanical stirring causes wear and damage. In addition, polyethylene resins and polypropylene resins are inherently hydrophobic, have a low affinity for microorganisms, and have a disadvantage that it is difficult to improve the efficiency of water treatment.

[0005] On the other hand, it is also known to use a foam molded article such as polyurethane foam as a carrier for water treatment. However, according to foam molding, it is difficult to mold to an arbitrary porosity. And it is difficult to improve the fluidity. In addition, the foam molded article has a disadvantage that it is difficult to mold into an arbitrary shape, and it is difficult to continuously mass-produce.

[0006] The present invention has been made in view of such disadvantages, and its object is to provide a liquid material having good fluidity.
An object of the present invention is to provide a water treatment carrier, a method for producing the water treatment carrier, and a water treatment apparatus using the water treatment carrier, which has excellent durability and can be produced with high productivity. .

[0007]

To achieve the above object, the present invention provides (1) a hydrophilic thermoplastic resin or
A carrier for water treatment, comprising a hydrophilic thermoplastic resin and at least one other thermoplastic resin and being porous; (2) a hydrophilic thermoplastic resin, or a hydrophilic carrier; The water treatment carrier according to (1), which is obtained by melt-molding a thermoplastic resin and one or more other thermoplastic resins together with a foaming agent.
(3) The carrier for water treatment according to (1) or (2), wherein the carrier for water treatment according to (1) or (2) is characterized by containing a substrate-adsorbed substance and / or a substance that improves enzyme activity or promotes growth. (5) a method for producing a carrier for water treatment, which comprises melt-molding a hydrophilic thermoplastic resin or a hydrophilic thermoplastic resin and at least one other thermoplastic resin together with a foaming agent; Hydrophilic thermoplastic resin, or
A water treatment apparatus comprising a hydrophilic water-repellent resin and one or more other thermoplastic resins, wherein a porous water-treatment carrier is used.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The water treatment carrier of the present invention is used for water treatment using microorganisms and the like, and is made of a hydrophilic thermoplastic resin or a hydrophilic thermoplastic resin and at least one other thermoplastic resin. It is made of resin and made porous.

By using a thermoplastic resin, it can be molded into an arbitrary shape by melt molding and can be continuously mass-produced. In addition, by using a hydrophilic thermoplastic resin, the initial water absorption is good, and the affinity of microorganisms is high, so that the adhesion and growth of microorganisms can be improved, thereby performing efficient water treatment. be able to. In the present invention, the hydrophilic thermoplastic resin refers to a resin that swells with water. Also,
By blending a hydrophilic thermoplastic resin with another thermoplastic resin, the specific gravity can be appropriately adjusted. For example, when used as a fluidized bed, its fluidity can be improved. Further, if a hydrophobic thermoplastic resin is used as the other thermoplastic resin, the hydrophobic thermoplastic resin becomes a hydrophobic portion, so that water can be prevented from entering, and as a result, decomposition by microorganisms can be prevented. And the strength of the water treatment carrier can be maintained.

Examples of such a hydrophilic thermoplastic resin include polyurethane resin, nylon resin, polyester resin, ethylene-vinyl alcohol copolymer, polycaprolactone resin, lactic acid polymer and poly (meth) acrylic resin. Is mentioned. Other thermoplastic resins include hydrophobic thermoplastic resins such as polyethylene resin, polypropylene resin, polyvinyl acetate resin, polyacetal resin, acrylonitrile-butadiene-styrene (ABS) resin, and acrylonitrile-styrene (AS) resin. , Polyvinyl chloride resin, polycarbonate resin, polyethylene polypropylene copolymer, polyvinylidene chloride resin and the like.

These may be used alone,
Two or more types may be used in combination. When blending a hydrophilic thermoplastic resin with another thermoplastic resin, the ratio of the hydrophilic thermoplastic resin is 5% of the total of the hydrophilic thermoplastic resin and the other thermoplastic resin. ~ 99% by weight, preferably
10 to 95% by weight. Preferably, a hydrophilic polyurethane resin or a mixture of a hydrophilic polyurethane resin and another thermoplastic resin is used.

The hydrophilic polyurethane resin usually contains a hydrophilic unit such as polyoxyethylene. In the hydrophilic polyurethane resin, a hydrophilic unit such as polyoxyethylene, polyoxypropylene and And / or a hydrophobic unit such as polyoxybutylene. By including a hydrophilic unit and a hydrophobic unit in the hydrophilic polyurethane resin, the hydrophilic unit improves the initial water absorption, increases the affinity of microorganisms, and improves the adhesion and growth of microorganisms. On the other hand, the hydrophobic unit makes it difficult for microorganisms to decompose even after long-term use, maintains strength, and ensures stable use. When the hydrophilic unit and the hydrophobic unit are contained, the ratio of the hydrophilic unit to the total is preferably 10 to 95% by weight, more preferably 20 to 90% by weight.

The water treatment carrier of the present invention preferably contains a substrate adsorbing substance and / or a substance which improves enzyme activity or promotes growth. By containing these, the microorganisms can be more easily attached and grown on the surface of the water treatment carrier,
Further efficient water treatment can be performed.

Examples of such a substrate adsorbing substance include natural ceramics containing natural stone, artificial ceramics, activated carbon, carbon black, silicate compounds and the like. These may be used alone,
Two or more types may be used in combination. Preferably, activated carbon and carbon black are used. The proportion of the substrate adsorbing substance is, for example, 0.1 to 40 parts by weight, or preferably 0.5 to 30 parts by weight, per 100 parts by weight of the thermoplastic resin.

Examples of the substance which enhances the enzyme activity or promotes growth include metals such as copper and zinc, and salts, oxides, sulfides, and water-insoluble or poorly-soluble salts of such metals in water. Examples thereof include oxides and the like, and those in which an inorganic substance and / or an organic substance are contained in such a metal or a metal compound. These may be used alone or in combination of two or more.
Preferably, copper oxide, copper sulfide, and copper hydroxide are used.
The proportion of the substance that improves the enzyme activity or promotes the growth is, for example, 0.005 to 5 parts by weight, preferably 0.05 parts by weight, per 100 parts by weight of the thermoplastic resin.
1 to 3 parts by weight.

The substance adsorbed on the substrate or the substance which improves the enzyme activity or promotes the growth may be prepared, for example, as a master batch.

The carrier for water treatment of the present invention comprises, for example, a hydrophilic thermoplastic resin, or a hydrophilic thermoplastic resin and at least one other thermoplastic resin, and if necessary, a substrate adsorbing substance. And / or a substance that improves the enzyme activity or promotes the growth of the enzyme is blended, and molded together with the foaming agent by a known melt molding method such as extrusion molding by a known melt molding machine such as an extruder. Can be obtained. In the extrusion molding, for example, so-called co-extrusion molding in which two or more kinds of thermoplastic resins can be simultaneously drawn out from two or more kinds of partitioned dies and freely shaped can be performed. In addition, as such molding conditions, for example, in the case of extrusion molding, when the screw diameter of single screw extrusion is 50 mmφ, the discharge rate is 5 to 35 kg / hr, the number of rotations of the screw is 10 to 80 min ⁻¹ , Temperature is 130-230 ° C
It is. Further, the shape to be molded, for example, when used as a fluidized bed, granular, spherical, cylindrical, cylindrical, bales,
What is necessary is just to shape into arbitrary shapes, such as a rice grain shape and a rugby ball shape. Also, the size is appropriately selected.
Those having a size of about 50 mm are preferable.

After the melt molding, the molded product may be discharged from a die and then cut by a cutting method such as underwater cutting, hot cutting, and mist cutting. For example, the surface can be made into a skin layer while the inside thereof is made porous by underwater cutting or hot cutting.

Examples of the foaming agent to be used include, for example, commonly used chemical foaming agents and physical foaming agents. As the chemical foaming agent, for example, azo compounds (eg, azodicarbonamide (ADCA), barium azodicarboxylate (Ba / AC), etc.), nitroso compounds (eg, N, N-dinitrosopentamethylenetetramine (DPT)) ), Hydrazine derivatives (e.g., 4,4'-oxybis (benzenesulfonylhydrazide) (OBSH), etc.), semicarbazide compounds, azide compounds, triazole compounds, isocyanate compounds, bicarbonates (e.g., sodium bicarbonate, etc.), Examples include carbonate, nitrite, hydride, a mixture of sodium bicarbonate and an acid (for example, sodium bicarbonate and citric acid), a mixture of hydrogen peroxide and yeast, a mixture of zinc powder and an acid, and the like.

Examples of the physical foaming agent include aliphatic hydrocarbons (eg, butane, pentane, hexane, etc.), chlorinated hydrocarbons (eg, dichloroethane, dichloromethane, etc.), fluorinated hydrocarbons (eg, , Trichloromonofluoromethane, dichlorodifluoromethane,
Dichloromonofluoromethane, dichlorotetrafluoroethane, etc.), alternative fluorocarbons, air, carbon dioxide, nitrogen gas,
Water. These may be used alone or in combination of two or more. Preferably, A
DCA, OBSH, a mixture of sodium bicarbonate and an acid.

The mixing ratio of the foaming agent is, for example, as follows:
It is 0.01 to 20 parts by weight, preferably 0.05 to 15 parts by weight, based on 100 parts by weight of the thermoplastic resin. In addition, these foaming agents may be prepared as a master batch, for example.

The water treatment carrier of the present invention thus obtained is made porous at the time of molding by a foaming agent.
The specific gravity of the water treatment carrier can be adjusted by adjusting the amount of the foaming agent to be used and appropriately selecting the porosity (also referred to as porosity or porosity) of the water treatment carrier. For example, when used as a fluidized bed, fluidity can be improved. In addition, by making the surface porous, irregular pores are usually formed on the surface, so that microorganisms can be easily attached to the surface, and more efficient water treatment can be achieved. Can be performed. Moreover, as compared with the case where a filler such as calcium carbonate or barium sulfate is blended with the thermoplastic resin, wear and damage are reduced and durability can be improved.

When such a foaming agent is used, its specific gravity is 0.93, which is close to the specific gravity of water (1.0).
To 1.15, preferably 0.97 to 1.05, more preferably 0.98 to 1.03, so that the porosity is 20 to 90%, , 2
It is preferably set to 0 to 80%. In addition, making porous
It may be an open cell or a closed cell, for example,
When the cells are closed cells, the size of the cells is 1 to 3
000 μm, more preferably 10 to 2000 μm.

The carrier for water treatment of the present invention thus obtained can be used for various kinds of water treatment, for example, wastewater treatment such as industrial wastewater and domestic wastewater, and more specifically, microorganisms. Water treatment, for example, nitrifying bacteria (eg,
Aerobic tank for treatment with aerobic microorganisms such as ammonia oxidizing bacteria and nitrite oxidizing bacteria) and anaerobic tank for treating with anaerobic microorganisms such as denitrifying bacteria. Can be used. FIG.
Shows an embodiment of such a water treatment device. That is, in FIG. 1, the water treatment apparatus includes a water treatment tank 1 used as an aerobic tank or an anaerobic tank, and a water supply pipe 2 and a drain pipe 3 connected to the water treatment tank 1. The water treatment carrier 4 of the present invention is charged into the water treatment tank 1 as a fluidized bed, and is stirred by a stirrer 5 rotatably provided in the water treatment tank 1. In such a water treatment apparatus, the water treatment carrier 4 whose specific gravity is adjusted by being made porous is used as a fluidized bed. But,
By effectively floating and settling, efficient water treatment can be performed.

The carrier for water treatment of the present invention is originally used for water treatment as described above, but it can also be used for treatment in the gas phase, for example, for deodorization of ammonia, hydrogen sulfide and the like. it can.

[0026]

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to Examples and Comparative Examples.

Example 1 A mixture of 80 parts by weight of a hydrophilic thermoplastic polyurethane resin (diphenylmethane diisocyanate / polyoxyethylene propylene glycol (ethylene oxide content: 80% by weight) and 20 parts by weight of polytetramethylene glycol / 1,4-butane) Diol, trade name: Elastolane
OH3-37, 100 parts by weight of Takeda Birdish Urethane Industry Co., Ltd .;
0% by weight, a mixture of sodium bicarbonate and citric acid 40
Wt% masterbatch, trade name: Hydrocerol-
0.5 part by weight of CF40E, manufactured by Boehringer Ingelheim Co., Ltd .; the same applies hereinafter), and molded using an extruder (50 mmφ single screw extruder, L / D = 34, manufactured by Ikegai Co., Ltd.), and an outer diameter of 3 mmφ To obtain a columnar carrier having a length of 3 mm.

Example 2 1.0 part by weight of a foaming agent was added to 100 parts by weight of a hydrophilic thermoplastic polyurethane resin, and an extruder (50 mmφ single screw extruder, L / D = 34, manufactured by Ikegai Co., Ltd.) was used. Then, a cylindrical carrier having an outer diameter of 3 mmφ and a length of 3 mm was obtained.

Example 3 2.5 parts by weight of a foaming agent was added to 100 parts by weight of a hydrophilic thermoplastic polyurethane resin, and an extruder (50 mmφ single screw extruder, L / D = 34, manufactured by Ikegai Co., Ltd.) was used. Then, a cylindrical carrier having an outer diameter of 3 mmφ and a length of 3 mm was obtained.

Example 4 100 parts by weight of a mixture in which a hydrophilic thermoplastic polyurethane resin and a polyethylene resin (trade name: Evolue SP0510, manufactured by Mitsui Chemicals, same hereafter) are mixed in a weight ratio of 8/2. Parts, a foaming agent (1.5 parts by weight) was added, and an extruder (50 mmφ single screw extruder, L / D = 3
4, Ikegai Co., Ltd.) to obtain a columnar carrier having an outer diameter of 3 mm and a length of 3 mm.

Example 5 A mixture 10 in which a hydrophilic thermoplastic polyurethane resin and a polyethylene resin are blended at a weight ratio of 8/2.
0 parts by weight, 3.0 parts by weight of a foaming agent were added, and the mixture was molded using an extruder (50 mmφ single screw extruder, L / D = 34, manufactured by Ikegai Co., Ltd.) to have an outer diameter of 3 mmφ and a length of 3 mm. Was obtained.

Example 6 A mixture 10 in which a hydrophilic thermoplastic polyurethane resin and a polyethylene resin were blended at a weight ratio of 8/2.
0.1 parts by weight of a foaming agent is added to 0 parts by weight, and the mixture is molded using an extruder (50 mmφ single screw extruder, L / D = 34, manufactured by Ikegai Co., Ltd.) to obtain an outer diameter of 4 mmφ, an inner diameter of 2 mmφ, Length 3
mm was obtained.

Example 7 A mixture 10 in which a hydrophilic thermoplastic polyurethane resin and a polyethylene resin were blended at a weight ratio of 8/2.
0 parts by weight, 0.3 parts by weight of a foaming agent are added, and the mixture is molded using an extruder (50 mmφ single screw extruder, L / D = 34, manufactured by Ikegai Co., Ltd.) to obtain an outer diameter of 4 mmφ, an inner diameter of 2 mmφ, Length 3
mm was obtained.

Example 8 A mixture 10 in which a hydrophilic thermoplastic polyurethane resin and a polyethylene resin were blended at a weight ratio of 8/2.
To 0 parts by weight, 0.7 parts by weight of a foaming agent was added, and the mixture was molded using an extruder (50 mmφ single screw extruder, L / D = 34, manufactured by Ikegai Co., Ltd.) to obtain an outer diameter of 4 mmφ, an inner diameter of 2 mmφ, Length 3
mm was obtained.

Example 9 A mixture 10 in which a hydrophilic thermoplastic polyurethane resin and a polyethylene resin were blended at a weight ratio of 8/2.
0 parts by weight, 0.5 part by weight of a foaming agent is added, and molded using an extruder (90 mmφ single screw extruder, L / D = 34, manufactured by Ikegai Co., Ltd.). Using a cutter (manufactured by Gala, the same applies hereinafter), underwater cutting was performed to obtain a 4 mmφ spherical carrier.

Example 10 A mixture 10 in which a hydrophilic thermoplastic polyurethane resin and a polyethylene resin were blended at a weight ratio of 8/2.
0 parts by weight, 2.0 parts by weight of a foaming agent are added, and the mixture is molded using an extruder (90 mmφ single screw extruder, L / D = 34, manufactured by Ikegai Co., Ltd.). Using a cutter, underwater cutting was performed to obtain a 4 mmφ spherical carrier.

Example 11 A mixture 10 in which a hydrophilic thermoplastic polyurethane resin and a polyethylene resin were blended at a weight ratio of 8/2.
0 parts by weight, 4.0 parts by weight of a foaming agent were added, and the mixture was molded using an extruder (90 mmφ single screw extruder, L / D = 34, manufactured by Ikegai Co., Ltd.). Using a cutter, underwater cutting was performed to obtain a 4 mmφ spherical carrier.

Example 12 A mixture 10 in which a hydrophilic thermoplastic polyurethane resin and a polyethylene resin were blended at a weight ratio of 8/2.
0 parts by weight, 6.0 parts by weight of a foaming agent were added, and the mixture was molded using an extruder (90 mmφ single screw extruder, L / D = 34, manufactured by Ikegai Co., Ltd.). Using a cutter, underwater cutting was performed to obtain a 4 mmφ spherical carrier.

Example 13 A mixture 10 in which a hydrophilic thermoplastic polyurethane resin and a polyethylene resin were blended at a weight ratio of 8/2.
0 parts by weight, 3.0 parts by weight of a foaming agent, 0.1 parts by weight of copper sulfide (manufactured by Wako Pure Chemical Industries, Ltd., the same applies hereinafter), activated carbon (trade name: DO-
5, Takeda Pharmaceutical Co., Ltd .; the same applies hereinafter) 3.0 parts by weight, and an extruder (50 mmφ single screw extruder, L / D = 3)
4, Ikegai Co., Ltd.) to obtain a columnar carrier having an outer diameter of 3 mm and a length of 3 mm.

Example 14 A mixture 10 in which a hydrophilic thermoplastic polyurethane resin and a polyethylene resin were blended at a weight ratio of 8/2.
To 0 parts by weight, 6.0 parts by weight of a foaming agent, 0.1 parts by weight of copper sulfide, and 3.0 parts by weight of activated carbon were added, and an extruder (90 m
mφ single screw extruder, L / D = 34, manufactured by Ikegai Co., Ltd.), and cut underwater using a submerged cutter immediately after discharging from the die to obtain a 4 mmφ spherical carrier. .

Comparative Example 1 85 parts by weight of polyether polyol (ethylene oxide adduct of sorbitol initiator, trade name: MF-43, manufactured by Takeda Pharmaceutical Co., Ltd.), polymer polyol (propylene oxide / ethylene oxide addition of glycerin initiator) And a polymer polyol comprising an acrylonitrile-styrene polymer, trade name: POP-93, manufactured by Takeda Pharmaceutical Co., Ltd.) 15 parts by weight, deionized water 3 parts by weight, dimethylsiloxane (manufactured by Wako Pure Chemical Industries, Ltd.) 1 part by weight, Tolylene diisocyanate (2,4 units / 80% by weight, 2,6 units / 2
(0% by weight, manufactured by Takeda Pharmaceutical Co., Ltd.) 15 parts by weight were reacted according to a conventional method to synthesize a hydrophilic polyurethane foam, which was cut into a 5 mm square to form a 5 mm square carrier made of a polyurethane foam. I got

Comparative Example 2 100 parts by weight of a mixture of a polyethylene resin and calcium carbonate so that the specific gravity thereof was 1.02 was
Molded using an extruder (50 mmφ single screw extruder, L / D = 34, manufactured by Ikegai Co., Ltd.), outer diameter 4 mmφ, inner diameter 2 mm
A cylindrical carrier having a diameter of φ and a length of 3 mm was obtained.

Test Example 1 The carriers of Examples 1 to 12 were dried in a hot air drier at 80 ° C. for 5 hours, and 100 g of the dried carriers were poured into 1 L of ion-exchanged water and allowed to swell, whereby the weight ratio (swelling weight / (Dry weight) and specific gravity (10% by volume of the carrier swollen in 1 L of water)
The flow rate when 0 mL was added was measured and calculated. ) Was measured. If air remains in the interior, the pressure was reduced to remove air bubbles. Table 1 shows the results.

[0044]

[Table 1]

Table 1 shows that the specific gravity can be adjusted by changing the amount of the foaming agent.

Test Example 2 The carriers obtained in Examples 5, 12, 13, 14 and Comparative Examples 1 and 2 were immersed in activated sludge to adsorb microorganisms. That is, a carrier having a bulk volume of 250 mL is put into 5 L of a draft flow water tank, and an inorganic artificial wastewater having the composition shown below is used. The water temperature is 20 ° C., the pH is 7.0 to 7.5, and the hydraulic retention time is 5 hours. The conditions were evaluated by obtaining the ammonia oxidation rate calculated from the amount of generated nitrous acid.

[0047] Inorganic artificial wastewater composition (per _{1L) (NH 4) 2 SO} 4 0.0943g KH 2 PO 4 0.6g NaHCO 3 0.375g MgSO 4 · 7H 2 O 10mg CaCl 2 · 2H 2 O 1.8mg Fe -EDTA 1 mg FIG. 2 shows the results of attaching ammonia oxidizing bacteria to the carriers of Examples 5, 12, 13, 14 and Comparative Examples 1 and 2, and evaluating the results. In the carrier of Comparative Example 1, air bubbles adhered and floated immediately after the start of the test, and the carrier could not be evaluated. Therefore, in FIG. 2, the result of Comparative Example 1 is omitted. In FIG. 2, the carriers of Examples 5, 12, 13, and 14 have good fluidity due to their specific gravities of 1.02 to 1.03, which are close to water, and are blended with a hydrophilic polyurethane resin. Therefore, it can be seen that the bacteria adhere and grow well, and the ammonia oxidation rate is satisfactorily increased. On the other hand, the carrier of Comparative Example 2 has a specific gravity of 1.02, which is close to that of water, but has poor adhesion of bacteria due to its hydrophobicity.
It can be seen that the ammonia oxidation rate did not increase as compared with 3 and 14. In addition, it can be seen that in Examples 13 and 14 containing the substrate adsorbing substance and the substance that improves the enzyme activity or promotes the growth, the ammonia oxidation rate rises quickly and the maximum activity is high.

The growth (dominance) of ammonia-oxidizing bacteria on the surface of each carrier was determined by the DNA probe method (FISH method).
Was evaluated using As a result, Examples 5, 12, 13,
It was confirmed that ammonia oxidizing bacteria proliferated and prioritized on the surface of the 14 carriers. Observations showed that 90% were ammonia oxidizing bacteria.

Test Example 3 Each of the carriers obtained in Example 12 and Comparative Example 2 was used in an amount of 1.0 m ³ in bulk volume (cylindrical carrier having an outer diameter of 8 mmφ and a length of 7 mm when swollen, a weight of 125 kg, and a filling amount of 20%)
This was put into a 5 m ³ water tank, and a durability test was performed using a mechanically agitated aerator (output: 0.75 kw, rotation speed: 560 to 570, manufactured by Shin-Meiwa Co., Ltd.).

The carrier of Example 12 did not appear to be visually deformed or damaged even after one month from the start of the test. On the other hand, the carrier of Comparative Example 2 was visually observed at one month after the start of the test to have a worn surface or a torn shape,
It was also confirmed that calcium carbonate was dispersed in water. Further, as a result of detailed observation with a scanning electron microscope (SEM), it was confirmed that the carrier of Example 12 was not worn, whereas the carrier of Comparative Example 2 was entirely worn. .

[0051]

The water treatment carrier of the present invention is made of a hydrophilic thermoplastic resin or a hydrophilic thermoplastic resin and at least one other thermoplastic resin, and is made porous. It can be molded into any shape by melt molding, can be continuously mass-produced, and is made porous at the time of molding with a foaming agent. The specific gravity of the water treatment carrier can be adjusted by appropriately selecting the porosity of the water treatment carrier. As a result, for example, when used as a fluidized bed, the fluidity can be improved. Further, as compared with the case where a filler such as calcium carbonate or barium sulfate is blended with the thermoplastic resin, wear and damage are reduced and durability can be improved. Moreover, by using a hydrophilic thermoplastic resin,
Since the initial water absorption is good and the affinity of the microorganisms is high, the adhesion and growth of the microorganisms can be improved, whereby more efficient water treatment can be performed.

In addition, by allowing the water treatment carrier of the present invention to contain a substrate-adsorbing substance and / or a substance that improves enzyme activity or promotes growth, microorganisms can be easily applied to the surface of the water treatment carrier. It can adhere and proliferate, and can perform more efficient water treatment.

In the water treatment apparatus using such a water treatment carrier, the water treatment carrier flows well in the tank, so that efficient water treatment can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a water treatment apparatus of the present invention.

FIG. 2 is a diagram showing evaluation results of Test Example 2, in which an ammonia oxidation rate is plotted with respect to elapsed days.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water treatment tank 2 Water supply pipe 3 Drain pipe 4 Carrier for water treatment 5 Stirrer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D003 AA13 EA01 EA14 EA15 EA19 EA22 EA24 EA25 EA26 EA30 EA38 EA40 FA10 4D040 BB63 BB82

Claims (5)

[Claims] 1. A water treatment carrier comprising a hydrophilic thermoplastic resin, or a hydrophilic thermoplastic resin and at least one other thermoplastic resin, which is made porous. 2. Hydrophilic thermoplastic resin, or hydrophilic thermoplastic resin and one or more other thermoplastic resins,
The water treatment carrier according to claim 1, wherein the carrier is obtained by melt-molding with a blowing agent. 3. The water treatment carrier according to claim 1, wherein the carrier for water treatment contains a substance adsorbed on a substrate and / or a substance that improves enzyme activity or promotes growth. 4. The method of claim 1, wherein the hydrophilic thermoplastic resin, or the hydrophilic thermoplastic resin and one or more other thermoplastic resins,
A method for producing a water treatment carrier, comprising melt-forming together with a foaming agent. 5. A water treatment carrier made of a hydrophilic thermoplastic resin or a hydrophilic thermoplastic resin and at least one other thermoplastic resin, which is made porous. Characteristic device for water treatment.