JP4489893B2 - Water treatment carrier, method for producing water treatment carrier and water treatment device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water treatment carrier used for various types of water treatment using microorganisms, a method for producing the water treatment carrier, and a water treatment apparatus using the water treatment carrier.
[0002]
[Prior art]
Conventionally, in water treatment such as waste water treatment using microorganisms, for example, a water treatment carrier made of a molded product of synthetic resin is introduced as a fluidized bed into a water treatment tank such as an anaerobic tank or an aerobic tank. . This carrier for water treatment is for water treatment by adhering microorganisms in the tank and allowing the adhering microorganisms to grow, and is usually formed into a cylindrical shape or a cylindrical shape by extrusion molding or the like. ing.
[0003]
[Problems to be solved by the invention]
However, in such a water treatment carrier molded into a cylindrical shape or a columnar shape, the corners of the water treatment carrier are scraped with use, and the shaved portion may cause contamination or the shaved portion. As a result, the chemical oxygen demand (C.O.D.) may become high, and there is a problem that it cannot be used stably over a long period of time. On the other hand, in ordinary extrusion molding, it is difficult to form a shape having no corners.
[0004]
The present invention has been made in view of such circumstances, and its object is to obtain a water treatment carrier that is obtained by a simple and reliable method, can be used stably over a long period of time, and has excellent durability. Another object of the present invention is to provide a method for producing the water treatment carrier and a water treatment apparatus using the water treatment carrier.
[0005]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention provides:
(1) It consists of a hydrophilic thermoplastic resin and a hydrophobic thermoplastic resin.Do not melt mold the thermoplastic resinThe hydrophilic thermoplastic resinThe hydrophilic unit containing polyoxyethylene and the hydrophobic unit containing polyoxypropylene and / or polyoxybutylene are included so that the ratio of the hydrophilic unit is 10 to 95% by weight based on the total.Hydrophilic polyurethane resinTheIt is characterized by having a shape without corners obtained by melt-molding a thermoplastic resin and then cutting by a method selected from the group consisting of underwater cut, hot cut, and mist cut. , Water treatment carrier,
(2) The water treatment carrier according to (1), wherein the surface has irregularities,
(3) It consists of a hydrophilic thermoplastic resin and a hydrophobic thermoplastic resin.A method for producing a water treatment carrier obtained by melt molding a thermoplastic resin comprising:A hydrophilic thermoplastic resinThe hydrophilic unit containing polyoxyethylene and the hydrophobic unit containing polyoxypropylene and / or polyoxybutylene are included so that the ratio of the hydrophilic unit is 10 to 95% by weight based on the total.Hydrophilic polyurethane resinTheProduction of a carrier for water treatment, wherein the thermoplastic resin is melt-molded and then cut by any method selected from the group consisting of underwater cut, hot cut, and mist cut to form a shape having no corners. Method,
(4) A thermoplastic resin comprising a hydrophilic thermoplastic resin and a hydrophobic thermoplastic resin, wherein the hydrophilic thermoplastic resin is a hydrophilic polyurethane resin and melt-molded with a foaming agent, and then hot cut or The method for producing a water treatment carrier according to (3), characterized by cutting by mist cutting,
(5) It is composed of a hydrophilic thermoplastic resin and a hydrophobic thermoplastic resin, and the hydrophilic thermoplastic resin is melt-molded together with soluble particles, and is then cut in water. (3) or (4), characterized in that cutting is performed by any method selected from the group consisting of hot cut and mist cut, and then soluble particles on the surface of the obtained molded product are dissolved and removed. A method for producing a water treatment carrier according to claim 1,
(6) It consists of a hydrophilic thermoplastic resin and a hydrophobic thermoplastic resin.A water treatment apparatus using a water treatment carrier formed by melt-molding a thermoplastic resin.A hydrophilic thermoplastic resinThe hydrophilic unit containing polyoxyethylene and the hydrophobic unit containing polyoxypropylene and / or polyoxybutylene are included so that the ratio of the hydrophilic unit is 10 to 95% by weight based on the total.Hydrophilic polyurethane resinTheA water treatment carrier having a shape with no corners, obtained by melt-molding a thermoplastic resin and then being cut by any method selected from the group consisting of underwater cut, hot cut, and mist cut Water treatment apparatus characterized by being used
Is included.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The carrier for water treatment of the present invention is used for water treatment using microorganisms and has a shape with no corners. Here, the shape having no corners refers to a shape having a surface with no corners or sharp points, although the overall shape is not limited.
[0007]
The carrier for water treatment of the present invention having such a shape having no corners is cut by any method selected from the group consisting of underwater cut, hot cut and mist cut after melt-molding a thermoplastic resin. Can be obtained.
[0008]
  As a thermoplastic resin,parentWith water-based thermoplastic resinHydrophobicWith a thermoplastic resinA thermoplastic resin comprising a hydrophilic thermoplastic resin and a hydrophobic thermoplastic resin obtained byUsed. By using a thermoplastic resin, it can be molded into an arbitrary shape by melt molding, and if the thermoplastic resin is hydrophilic, the initial water absorption is good and the affinity of microorganisms is high. Adhesion and growth can be improved, thereby enabling efficient water treatment. In the present invention, the hydrophilic thermoplastic resin refers to a resin that swells with water. Also, a hydrophilic thermoplastic resin andHydrophobicThe specific gravity can be adjusted as appropriate if it is blended with the thermoplastic resin. For example, when it is used as a fluidized bed, its fluidity can be improved. furtherSparseIf an aqueous thermoplastic resin is used, 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 increased. Can be held.
[0009]
  As such a hydrophilic thermoplastic resin,, HydrophilicRiurethane treeFat is used. Also,HydrophobicAs a thermoplastic resin, ExampleFor example, polyethylene resin, polypropylene resin, polyvinyl acetate resin, polyacetal resin, acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene (AS) resin, polyvinyl chloride resin, polycarbonate resin, polyethylene polypropylene copolymer, polychlorinated Examples include vinylidene resin.
[0010]
parentWith water-based thermoplastic resinHydrophobicWith thermoplastic resinAs a blending ratio ofThe ratio of the hydrophilic thermoplastic resin is different from the hydrophilic thermoplastic resin.Hydrophobic5 to 99% by weight, preferably 10 to 95% by weight, based on the total of the thermoplastic resin.
[0011]
  The hydrophilic polyurethane resin isTheContains hydrophilic units such as reoxyethylene and hydrophobic units such as polyoxypropylene and / or polyoxybutyleneTheBy 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 to be decomposed by microorganisms even when used for a long time, maintains strength, and ensures stable use. Also,In hydrophilic polyurethane resin,When the hydrophilic unit and the hydrophobic unit are included, the ratio of the hydrophilic unit is 10 to 95% by weight with respect to the total.And preferably20-90% by weightThe
[0012]
In addition, the water treatment carrier of the present invention preferably contains a substrate adsorbing substance and / or a substance that improves enzyme activity or promotes growth. By containing these, microorganisms can be more easily attached and grown on the surface of the water treatment carrier, and more efficient water treatment can be performed.
[0013]
Examples of such substrate-adsorbing substances include natural ceramics containing natural stone, artificial ceramics, activated carbon, carbon black, and silicate compounds. These may be used alone or in combination of two or more. Preferably, activated carbon and carbon black are used. Moreover, the ratio which mix | blends a substrate adsorption substance is 0.1-40 weight part with respect to 100 weight part of thermoplastic resins, for example, Preferably, it is 0.5-30 weight part.
[0014]
Examples of substances that improve enzyme activity or promote growth include metals such as copper and zinc, and salts, oxides, sulfides and hydroxides of such metals that are insoluble or sparingly soluble in water. Furthermore, those containing an inorganic substance and / or an organic substance in such a metal or metal compound can be mentioned. These may be used alone or in combination of two or more. Preferably, copper oxide, copper sulfide, and copper hydroxide are used. Moreover, the ratio which mix | blends the substance which improves enzyme activity or promotes growth is 0.005-5 weight part with respect to 100 weight part of thermoplastic resins, Preferably, it is 0.01-3 weight part. .
[0015]
The substrate adsorbing substance and the substance that improves enzyme activity or promotes growth may be prepared as a master batch, for example.
[0016]
The water treatment carrier of the present invention includes, for example, a thermoplastic resin and, if necessary, a substrate-adsorbing substance and / or a substance that improves enzyme activity or a substance that promotes growth. It can be obtained by a melt molding machine after melt molding at a melting temperature equal to or higher than the raw material to be used, after discharging from a die, and then cutting by any method selected from underwater cut, hot cut, and mist cut.
[0017]
In the underwater cutting, for example, a molten thermoplastic resin discharged from a die is cut in water. In the hot cut, for example, a molten thermoplastic resin discharged from a die is cut while being melted and dropped into water. In the mist cutting, for example, cutting is performed while spraying water on a molten thermoplastic resin discharged from a die in a mist form. If cut by such underwater cut, hot cut, mist cut, the molded product is easily and reliably formed into a shape without corners, that is, a shape having a surface with no corners or sharp points. Can do.
[0018]
As the molding conditions for such a water treatment carrier, for example, the extrusion rate is 10 to 100 kg / hr when the screw diameter is 90 mmφ, and the temperature of the die to be discharged is preferably 110 to 250 ° C. Is 130-220 ° C. Moreover, as a cutting condition, the rotational speed of the cutter is 100 to 5000 min.^-1, Preferably, 500 to 4000 min^-1The water temperature is 5 to 80 ° C, preferably 10 to 70 ° C.
[0019]
Moreover, what is necessary is just to shape | mold the shape to shape | mold, for example, when using as a fluidized bed, arbitrary shapes, such as a granular form, a spherical form, a column shape, a cylindrical shape, a bowl shape, a rice grain shape, and a rugby ball shape. Moreover, the size is also selected suitably, for example, the thing of about 1-50 mm is preferable.
[0020]
And since the water treatment support | carrier of this invention obtained in this way has a shape without an angle | corner, even if it uses it, for example as a fluidized bed, and mechanically stirs, there are few abrasion and a shape change. Therefore, it is possible to attach and grow microorganisms stably over a long period of time without causing contamination due to scraping of the water treatment carrier or increasing the chemical oxygen demand (C.O.D.). Thereby, an efficient water treatment can be performed.
[0021]
The water treatment carrier of the present invention preferably has irregularities formed on the surface thereof. By forming irregularities on the surface, microorganisms can be easily attached to the surface, and more efficient water treatment can be performed.
[0022]
In addition, an unevenness | corrugation refers to the shape which has the unevenness | corrugation of width 5-1000 micrometers, for example, Preferably, 10-750 micrometers, depth 0.01-100 micrometers, Preferably it is 0.1-75 micrometers.
[0023]
Such unevenness can be formed, for example, by melt-molding a thermoplastic resin together with a foaming agent and making the resulting molded product porous by performing a predetermined cut.
[0024]
Examples of the foaming agent to be used include chemical foaming agents and physical foaming agents that are usually used. Examples of the chemical blowing agent include azo compounds (for example, azodicarbonamide (ADCA), barium azodicarboxylate (Ba / AC), etc.), nitroso compounds (for example, N, N-dinitrosopentamethylenetetramine (DPT). )), Hydrazine derivatives (such as 4,4′-oxybis (benzenesulfonylhydrazide) (OBSH)), semicarbazide compounds, azide compounds, triazole compounds, isocyanate compounds, bicarbonates (such as sodium bicarbonate), Examples thereof include carbonate, nitrite, hydride, a mixture of sodium bicarbonate and acid (for example, sodium bicarbonate and citric acid), a mixture of hydrogen peroxide and yeast, a mixture of zinc powder and acid, and the like.
[0025]
Examples of the physical foaming agent include aliphatic hydrocarbons (eg, butane, pentane, hexane, etc.), chlorinated hydrocarbons (eg, dichloroethane, dichloromethane, etc.), fluorinated chlorohydrocarbons (eg, trichloromono). Fluoromethane, dichlorodifluoromethane, dichloromonofluoromethane, dichlorotetrafluoroethane, etc.), alternative chlorofluorocarbons, air, carbon dioxide, nitrogen gas, water and the like. These may be used alone or in combination of two or more. Preferably, ADCA, OBSH, and a mixture of sodium bicarbonate and acid are used.
[0026]
Moreover, the ratio which mix | blends a foaming agent is 0.01-20 weight part with respect to 100 weight part of thermoplastic resins, for example, Preferably, it is 0.05-15 weight part. In addition, these foaming agents may be prepared as a masterbatch, for example.
[0027]
If such a foaming agent is used to form irregularities on the surface of the water treatment carrier, not only the surface but also the inside of the carrier is made porous. The specific gravity of the water treatment carrier can be adjusted by appropriately selecting the porosity (also referred to as porosity or porosity) of the carrier for water treatment. As a result, for example, fluidity can be improved when used as a fluidized bed. When used as such a fluidized bed, the porosity is preferably 5 to 95%, more preferably 10 to 90% in order to bring the specific gravity close to the specific gravity of water (1.0). . The porosity may be open cells or closed cells. For example, in the case of closed cells, the size of the bubbles is 1 to 3000 μm, and further 10 to 2000 μm. Is preferred.
[0028]
Moreover, in order to form an unevenness | corrugation on the surface of the carrier for water treatment with a foaming agent, it is preferable to cut by a hot cut and a mist cut. According to the underwater cut, the porous surface may be blocked. Further, even in the case of hot cutting, in order to prevent clogging of the porous surface, for example, the ratio of the foaming agent when the die size is 3 mmφ is, for example, 100 parts by weight of the thermoplastic resin. It is preferable to exceed 2 parts by weight.
[0029]
In addition, the formation of the unevenness may be formed, for example, by melt-molding a thermoplastic resin together with soluble particles and dissolving and removing soluble particles on the surface of the obtained molded product after completion of a predetermined cut. it can.
[0030]
The soluble particles are preferably those that are well dispersed in the thermoplastic resin and uniformly distributed on the surface thereof during melt molding, and examples thereof include inorganic salts such as calcium carbonate, sodium chloride, and potassium chloride. The particle diameter of such soluble particles is, for example, preferably from 0.1 to 2000 μm, and more preferably from 1 to 1000 μm, and the blending ratio is, for example, 5 to 80% by weight in the component to be melt-molded, preferably Is from 10 to 75% by weight.
[0031]
More specifically, for example, when calcium carbonate is used, it may be melt-molded and subjected to acid treatment after a predetermined cut. As the acid treatment, for example, a molded product obtained by cutting may be impregnated with an acid solution such as an aqueous hydrochloric acid solution. Thereby, calcium carbonate on the surface of the obtained molded product is dissolved to form pores, and as a result, irregularities are formed on the surface of the water treatment carrier.
[0032]
Further, for example, when sodium chloride is used, it may be melt-molded and subjected to a water washing treatment after a predetermined cut. As the water washing treatment, for example, a molded product obtained by cutting may be immersed in water. Thereby, sodium chloride on the surface of the obtained molded product is dissolved to form pores, and as a result, irregularities are formed on the surface of the water treatment carrier.
[0033]
In addition, formation of such an unevenness | corrugation may use a foaming agent and a soluble particle individually, respectively, and may use these together. For example, as described above, when only the foaming agent is used, according to the underwater cutting, the porous surface may be blocked, but the foaming agent and soluble particles are used in combination, and the underwater cutting is performed. Thus, it is possible to form a water treatment carrier in which irregularities are formed on the surface and the inside thereof is also made porous.
[0034]
The water treatment carrier of the present invention thus obtained can be used for various types of water treatment, for example, waste water treatment such as industrial waste water and domestic waste water, and more specifically, water treatment using microorganisms. For example, an aerobic tank for treating with an aerobic microorganism such as nitrifying bacteria (for example, ammonia oxidizing bacteria, nitrite oxidizing bacteria, etc.), an anaerobic tank for treating with anaerobic microorganisms such as denitrifying bacteria, It can be used as a fixed bed, in particular as a fluidized bed. FIG. 1 shows an embodiment of such a water treatment apparatus. 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. In the water treatment tank 1, the water treatment carrier 4 of the present invention is charged as a fluidized bed, and is stirred by a stirrer 5 that is rotatably provided in the water treatment tank 1. In such a water treatment apparatus, since the water treatment carrier 4 having a shape with no corners is used as a fluidized bed, even if it is stirred by the stirrer 5, there is little change in wear and shape. Therefore, it does not cause contamination due to scraping of the water treatment carrier 4 or increase in chemical oxygen demand (C.O.D.). It can be used stably.
[0035]
The water treatment carrier of the present invention is originally used for water treatment as described above, but can also be used for treatment in a gas phase, for example, deodorization of ammonia, hydrogen sulfide, and the like.
[0036]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the examples and comparative examples.
[0037]
    ComparisonExample 1
  Hydrophilic thermoplastic polyurethane resin (mixture of 80 parts by weight of diphenylmethane diisocyanate / polyoxyethylene propylene glycol (ethylene oxide content 80% by weight) and 20 parts by weight of polytetramethylene glycol / 1,4-butanediol, trade name: D 100 parts by weight of Lastlan OH3-37 (manufactured by Takeda Burdish Urethane Kogyo Co., Ltd., the same shall apply hereinafter) is used using an extrusion molding machine (90 mmφ single screw extruder, L / D = 34, die temperature 190 ° C., Ikegai Co., Ltd.). Immediately after forming and discharging from the die, underwater cutter (cutter rotation speed 2700min^-1And a water temperature of 35 to 40 ° C., manufactured by Gala Co., Ltd., and the same below) was cut in water to obtain a 4 mmφ spherical carrier.
[0038]
    ComparisonExample 2
  5 parts by weight of a foaming agent (master batch of polyvinyl acetate resin 70% by weight, ADCA 30% by weight, trade name: Polyslen EV306, manufactured by Eiwa Kasei Co., Ltd.) is added to 100 parts by weight of a hydrophilic thermoplastic polyurethane resin, and extrusion molding is performed. Machine (90mmφ single screw extruder, L / D = 34, die temperature 190 ° C, manufactured by Ikegai Co., Ltd.). The carrier was obtained.
[0039]
    ComparisonExample 3
  100 parts by weight of hydrophilic thermoplastic polyurethane resin, calcium carbonate masterbatch (a mixture of hydrophilic thermoplastic polyurethane resin and calcium carbonate (trade name: SS30, manufactured by Nitto Flour & Chemical Co., Ltd.) 40% by weight, The same applies hereinafter) 100 parts by weight and 5 parts by weight of a foaming agent (master batch of polyvinyl acetate resin 70% by weight, ADCA 30% by weight, trade name: Polyslen EV306, manufactured by Eiwa Kasei Co., Ltd.) are added to an extruder (120 mmφ) Single-screw extruder, L / D = 34, die temperature 190 ° C., manufactured by Ikekai Co., Ltd.), and immediately after discharging from the die, an underwater cutter is used to perform underwater cutting. By impregnating with a 2N-hydrochloric acid aqueous solution and dissolving calcium carbonate on the surface thereof, a 4 mmφ spherical carrier having pores on the surface was obtained.
[0040]
    Example1
  Calcium carbonate master is added to 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, Inc., the same applies hereinafter) are blended at a ratio of 8/2 by weight. 100 parts by weight of a batch and 5 parts by weight of a foaming agent (master batch of polyvinyl acetate resin 70% by weight, ADCA 30% by weight, trade name: Polyslen EV306, manufactured by Eiwa Kasei Co., Ltd.) were added, and an extruder (90 mmφ uniaxial) Extruder, L / D = 34, die temperature 190 ° C., manufactured by Ikegai Co., Ltd.) and immediately after discharging from the die, an underwater cutter is used to perform underwater cutting. A 4 mmφ spherical carrier having pores on the surface was obtained by impregnating with an aqueous hydrochloric acid solution and dissolving calcium carbonate on the surface.
[0041]
    Example2
  100 parts by weight of a mixture in which a hydrophilic thermoplastic polyurethane resin and a polyethylene resin are blended in a ratio of 6/4 by weight, 100 parts of calcium carbonate masterbatch, and a foaming agent (70 parts by weight of polyvinyl acetate resin) %, ADCA 30 wt% master batch, trade name: Polyslen EV306, manufactured by Eiwa Kasei Co., Ltd. 5 parts by weight are added, and an extrusion molding machine (90 mmφ single screw extruder, L / D = 34, die temperature 190 ° C., Ikekai Made by using an underwater cutter immediately after discharging from the die, and underwater cutting, and impregnating the resulting molding with a 2N hydrochloric acid aqueous solution to dissolve calcium carbonate on the surface. Thus, a 4 mmφ spherical carrier having pores on the surface was obtained.
[0042]
    Example3
  Calcium carbonate is added to 100 parts by weight of a mixture in which a hydrophilic thermoplastic polyurethane resin and an ABS resin (trade name: SWR-1, manufactured by Mitsubishi Rayon Co., Ltd., hereinafter the same) are blended at a ratio of 8/2 by weight. 100 parts by weight of master batch and 6 parts by weight of blowing agent (60% by weight of polyethylene resin, 40% by weight of a mixture of sodium bicarbonate and citric acid, trade name: Hydrocerol-CF40E, manufactured by Boehringer Ingelheim) Part is molded using an extrusion molding machine (90 mmφ single-screw extruder, L / D = 34, die temperature 190 ° C., manufactured by Ikegai Co., Ltd.), and using an underwater cutter immediately after discharge from the die, Cut in water, impregnate the resulting molded product with 2N-hydrochloric acid aqueous solution, dissolve calcium carbonate on the surface, and have 4mmφ pores on the surface It was obtained Jo of the carrier.
[0043]
    Example4
  100 parts by weight of a mixture of a hydrophilic thermoplastic polyurethane resin and an ABS resin in a ratio of 6/4 by weight, 100 parts by weight of a calcium carbonate masterbatch, and a blowing agent (60% by weight of polyethylene resin) , 6 parts by weight of a master batch of 40% by weight of a mixture of sodium bicarbonate and citric acid, trade name: Hydrocerol-CF40E, manufactured by Boehringer Ingelheim Co., Ltd., and an extrusion molding machine (90 mmφ single screw extruder, L / D = 34, die temperature 190 ° C., manufactured by Ikegai Co., Ltd.) and immediately after discharging from the die, it is cut in water using an underwater cutter, and the resulting molded product is impregnated with 2N hydrochloric acid aqueous solution. Then, by dissolving calcium carbonate on the surface, a 4 mmφ spherical carrier having pores on the surface was obtained.
[0044]
    ComparisonExample4
  100 parts by weight of a hydrophilic thermoplastic polyurethane resin, 5 parts by weight of a foaming agent (70% by weight of polyvinyl acetate resin, 30% by weight of master batch of ADCA, trade name: Polyslen EV306, manufactured by Eiwa Chemical Co., Ltd.), activated carbon (trade name: 2 parts by weight of DO-5, manufactured by Takeda Pharmaceutical Co., Ltd., the same shall apply hereinafter) and 0.2 parts by weight of copper oxide (manufactured by Wako Pure Chemicals, the same shall apply hereinafter) D = 34, die temperature 190 ° C., manufactured by Ikegai Co., Ltd.) and immediately after discharging from the die, a mist cutter is used, and mist cutting is performed while water is poured in a shower shape, and the surface has pores. A spherical carrier having a diameter of 4 to 5 mmφ was obtained.
[0045]
    Example5
  In 100 parts by weight of a mixture in which a hydrophilic thermoplastic polyurethane resin and a polyethylene resin are blended at a ratio of 8/2 by weight, 100 parts by weight of a calcium carbonate masterbatch and a foaming agent (polyvinyl acetate resin 70 5% by weight, 5% by weight of master batch of ADCA, 30% by weight of ADCA, trade name: Polyslen EV306, manufactured by Eiwa Kasei Co., Ltd., 5 parts by weight of activated carbon, and 0.2 parts by weight of copper oxide are added to an extruder (90 mmφ single screw extruder) L / D = 34, die temperature 190 ° C., manufactured by Ikegai Co., Ltd.), immediately after discharging from the die, using an underwater cutter to cut in water, and the resulting molded product is 2N-hydrochloric acid aqueous solution. Was impregnated, and calcium carbonate on the surface thereof was dissolved to obtain a 4 mmφ spherical carrier having pores on the surface.
[0046]
    Example6
  100 parts by weight of a mixture of hydrophilic thermoplastic polyurethane resin and polyethylene resin in a ratio of 6/4 by weight, 100 parts by weight of calcium carbonate masterbatch, and blowing agent (70% by weight of polyvinyl acetate resin) , ADCA 30 wt% master batch, trade name: Polyslen EV306, manufactured by Eiwa Kasei Co., Ltd.) 5 parts by weight, activated carbon 5 parts by weight, copper oxide 0.2 parts by weight are added and an extrusion molding machine (90 mmφ single screw extruder, L / D = 34, die temperature 190 ° C., manufactured by Ikegai Co., Ltd.) and immediately after discharging from the die, it is cut in water using an underwater cutter, and the resulting molded product is impregnated with 2N hydrochloric acid aqueous solution. Then, by dissolving calcium carbonate on the surface, a 4 mmφ spherical carrier having pores on the surface was obtained.
[0047]
    ComparisonExample5
  100 parts by weight of sodium chloride (Naikai salt, manufactured by Neolite Kosan Co., Ltd., hereinafter the same) is added to 100 parts by weight of a hydrophilic thermoplastic polyurethane resin, and an extrusion molding machine (90 mmφ single screw extruder, L / D = 34, die At a temperature of 190 ° C., manufactured by Ikegai Co., Ltd.), immediately after discharging from the die, using an underwater cutter, and cutting in water, immersing the resulting molded product in water, and removing sodium chloride on the surface. By dissolving, a 4 mmφ spherical carrier having pores on the surface was obtained.
[0048]
    Example7
  100 parts by weight of a mixture in which a hydrophilic thermoplastic polyurethane resin and a polyethylene resin are blended at a ratio of 8/2 by weight, 100 parts by weight of sodium chloride, a foaming agent (70% by weight of polyvinyl acetate resin, ADCA30) 5% by weight master batch, trade name: Polyslen EV306, manufactured by Eiwa Kasei Co., Ltd.), 5 parts by weight of activated carbon, 0.1 parts by weight of copper oxide were added, and an extruder (90 mmφ single screw extruder, L / D) = 34, die temperature 190 ° C, manufactured by Ikegai Co., Ltd.), immediately after discharging from the die, using an underwater cutter to cut in water, and immersing the resulting molded product in water, Was dissolved to obtain a 4 mmφ spherical carrier having pores on the surface.
[0049]
    Comparative example6
  100 parts by weight of a mixture in which a polyethylene resin and calcium carbonate are blended at a ratio of 7/3 by weight ratio, an extrusion molding machine (90 mmφ single screw extruder, L / D = 34, die temperature 190 ° C., manufactured by Ikekai ), Discharged from the die, cooled, and cut to obtain a columnar carrier having an outer diameter of 4 mmφ and a length of 5 mm.
[0050]
    Test example 1
  Example 17And Comparative Example 1~ 5Each carrier obtained in 1) is 0.5 m in actual volume.³Use this 5m³And a durability test was conducted using a mechanical stirring aerator (output 0.75 kw, manufactured by Shin Meiwa Kogyo Co., Ltd.).
[0051]
  Example 17 and comparative examples1 to5Even after 2 weeks from the start of the test, the surface of this carrier does not appear to be worn on the surface, and as a result of detailed observation with a scanning electron microscope (SEM), it is confirmed that the carrier is not worn. It was done. On the other hand, comparative example6When 1 week had elapsed from the start of the test, the carrier of No. 1 seemed to have a worn surface, and water was also turbid. Further, as a result of detailed observation with a scanning electron microscope (SEM), it was confirmed that the entire surface was worn.
[0052]
    Test example 2
  Example1-4,6,7And comparative examples3, 6Was immersed in activated sludge to adsorb microorganisms. That is, a carrier having a bulk volume of 250 mL is put into a draft flow water tank 5 L, inorganic artificial wastewater having the following composition is used, water temperature 20 ° C., pH 7.0 to 7.5, hydraulic residence time 5 Evaluation was made by determining the ammonia oxidation rate calculated from the amount of nitrous acid produced under the conditions of time.
[0053]
                    Inorganic artificial wastewater composition (per liter)
      (NH₄)₂SO₄0.0943g
        KH₂PO₄0.6g
        NaHCO₃0.375g
        MgSO₄・ 7H₂O 10mg
        CaCl₂・ 2H₂O 1.8mg
        Fe-EDTA 1mg
  FIG. 2 shows the results of evaluation by attaching ammonia oxidizing bacteria to each carrier. In FIG.1-4, 6, 7 and Comparative Example 3The carrier in this example was a comparative example because bacteria adhered to the irregularities formed on its surface and grew.6It can be seen that the ammonia oxidation rate is increased favorably. Examples containing a substrate-adsorbing substance and a substance that improves enzyme activity or promotes growth6,7It can be seen that the rise of the ammonia oxidation rate is fast and the maximum activity is high.
[0054]
  In addition, the growth (dominance) of ammonia-oxidizing bacteria on the surface of each carrier was evaluated using the DNA probe method (FISH method). As a result, the example1-4, 6, 7 and Comparative Example 3It was confirmed that ammonia-oxidizing bacteria grew and preferred on the surface of the carrier. On observation, 90% were ammonia oxidizing bacteria.
[0055]
  Test example 3
  Example5And comparative examples5, 6400 mL of this carrier is introduced into an aerobic tank of an activated sludge anaerobic aerobic treatment apparatus (anaerobic tank 3L, aerobic tank 2L), and at 20 ° C., continuous flow of artificial artificial wastewater having the composition shown below. Processing was performed. The hydraulic residence time in the aerobic tank was 1.6 hours, and the activity of the carrier was evaluated by calculating the nitrification rate from the quality of artificial wastewater and treated water. The result is shown in FIG. In addition, in FIG. 3, the nitrification rate of the system of only the activated sludge which did not throw a support | carrier is also shown collectively. In FIG. 3, the embodiment5 and Comparative Example 5The carrier is a comparative example6It can be seen that the nitrification rate is clearly higher than that of the system of only activated sludge, and that efficient nitrification can be performed.
[0056]
                    Living system artificial wastewater composition (per liter)
        Polypeptone 140 mg / mL
        glucose 140 mg / mL
      (NH₄)₂SO₄220 mg / mL
        KH₂PO₄25 mg / mL
        NaHCO₃150 mg / mL
        NaCl 100 mg / mL
  In addition, the growth (dominance) of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria on the surface of each carrier was evaluated using the DNA probe method (FISH method). As a result, the example5 and Comparative Example 5It was confirmed that ammonia-oxidizing bacteria and nitrite-oxidizing bacteria formed colonies on the surface of the carrier and proliferated and preferred. In observation, 90% were ammonia oxidizing bacteria and nitrite oxidizing bacteria.
[0057]
【The invention's effect】
Since the water treatment carrier of the present invention has a shape with no corners, the corners are not scraped during the treatment, and contamination and chemical oxygen demand (C.O.D. .) Can be effectively prevented. Thereby, microorganisms can adhere and propagate stably over a long period of time, and an efficient water treatment can be performed. Moreover, the carrier for water treatment of the present invention can be easily and reliably squared by melt-molding a thermoplastic resin and then cutting it by any method selected from the group consisting of underwater cut, hot cut and mist cut. It can be obtained as a shape without.
[0058]
  Also, the water treatment carrier of the present inventionIs, Hydrophilic thermoplastic resinAnd hydrophobic thermoplastic resinFormed byForSince the initial water absorption is good and the affinity of microorganisms is high, the adhesion and growth of microorganisms can be improved, and thereby more efficient water treatment can be performed.
Further, since a hydrophilic polyurethane resin is used as the hydrophilic thermoplastic resin, the initial water absorption of the water treatment carrier is improved, the affinity of microorganisms is increased, and the adhesion and growth of microorganisms are improved. be able to.
[0059]
Further, in the water treatment carrier of the present invention, if the surface has irregularities, microorganisms are likely to adhere to the surface, and more efficient water treatment can be performed.
[0060]
And the water treatment apparatus in which such a water treatment carrier is used does not cause contamination due to scraping of the water treatment carrier or increase in chemical oxygen demand (C.O.D.). As a device having excellent durability and easy maintenance, it can be used stably over a long period of time.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of a water treatment apparatus of the present invention.
FIG. 2 is a diagram showing the evaluation result of Test Example 2 in which the ammonia oxidation rate is plotted against the elapsed days.
FIG. 3 shows the evaluation results of Test Example 3, in which the nitrification rate is plotted against the elapsed days.
[Explanation of symbols]
1 Water treatment tank
2 Water supply pipe
3 Drainage pipe
4 Water treatment carrier
5 Stirrer

Claims (6)

The thermoplastic resin ing a hydrophilic thermoplastic resin and a hydrophobic thermoplastic resin Ri name by melting,
The hydrophilic thermoplastic resin is composed of a hydrophilic unit containing polyoxyethylene and a hydrophobic unit containing polyoxypropylene and / or polyoxybutylene. Ri hydrophilic polyurethane resins der containing such that 95% by weight,
It is characterized by having a shape without corners obtained by melt-molding a thermoplastic resin and then cutting by a method selected from the group consisting of underwater cut, hot cut, and mist cut. Water treatment carrier.   The water treatment carrier according to claim 1, wherein the surface has irregularities. A method of manufacturing a hydrophilic thermoplastic resin and a hydrophobic thermoplastic a ing thermoplastic resin from a resin formed by melting water treating carrier,
The hydrophilic thermoplastic resin is composed of a hydrophilic unit containing polyoxyethylene and a hydrophobic unit containing polyoxypropylene and / or polyoxybutylene. Ri hydrophilic polyurethane resins der containing such that 95% by weight,
Production of a carrier for water treatment, wherein the thermoplastic resin is melt-molded and then cut by any method selected from the group consisting of underwater cut, hot cut, and mist cut to form a shape having no corners. Method.   It consists of a hydrophilic thermoplastic resin and a hydrophobic thermoplastic resin. After the thermoplastic resin, which is a hydrophilic polyurethane resin, is melt-molded with a foaming agent, it is hot-cut or mist-cut. The method for producing a water treatment carrier according to claim 3, wherein the water treatment carrier is cut.   It consists of a hydrophilic thermoplastic resin and a hydrophobic thermoplastic resin. After the thermoplastic resin, which is a hydrophilic polyurethane resin, is melt-molded with soluble particles, it is cut in water, hot cut, The water treatment according to claim 3 or 4, wherein the water treatment is performed by any method selected from the group consisting of mist cuts, and then the soluble particles on the surface of the obtained molded product are dissolved and removed. A method for producing a carrier. An apparatus for water treatment which hydrophilic thermoplastic resin and a hydrophobic thermoplastic comprising a ing thermoplastic resin from the resin melt molding water treating carrier is used,
The hydrophilic thermoplastic resin is composed of a hydrophilic unit containing polyoxyethylene and a hydrophobic unit containing polyoxypropylene and / or polyoxybutylene. Ri hydrophilic polyurethane resins der containing such that 95% by weight,
A water treatment carrier having a shape with no corners, obtained by melt-molding a thermoplastic resin and then being cut by any method selected from the group consisting of underwater cut, hot cut, and mist cut An apparatus for water treatment, which is used.

Images