JPH11276164A - Microbial carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a microbial carrier useful, e.g. for a low-cost high-efficiency waste water treatment by using a porous hollow tube, etc., made of a hydrophobic plastic as a substrate, introducing a water-soluble polymer containing microorganisms into the pore and insolubilizing the polymer. SOLUTION: The porous hollow tube or a pseudo-hollow tube having a C- shaped cross-section and made of a hydrophobic plastic selected from among polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, epoxy resin and their derivatives is used as a substrate. A water- soluble polymer containing microorganisms and composed of hydrolyzed product of N-vinylcarboxylic acid amide (co)polymer, hydrolyzed product of polyvinyl acetate, chitosan, sodium alginate, sodium polyacrylate or their mixture is introduced into the pore and the water-soluble polymer is insolubilized to obtain the objective microbial carrier exhibiting the effect at the start of the addition of the carrier and having high bio-processing capability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aerobic fluidized bed biological treatment apparatus used for biodegradation of organic substances and nitrification of ammonia nitrogen, or a non-fluidized bed biological apparatus used for denitrification reaction by reduction of nitrate nitrogen. The present invention relates to a plastic microbial carrier effective for purifying contaminated water by a treatment device, characterized in that microorganisms are held in pores in the carrier.

[0002]

2. Description of the Related Art As a method of treating wastewater, a fluidized bed biological treatment method in which a microorganism carrier is fluidized into a tank and assimilated microorganisms are efficiently separated from treated water together with the microorganism carrier, or a nitric acid / nitrite solution. Non-fluidized-bed biological treatment equipment using wastewater containing nitrate nitrogen such as nitrogen with an organic substance such as methanol for a denitrification reaction by reduction, etc., is known, including hydrogels composed of various cross-linked resins, polyethylene, polypropylene,
Plastic microbial carriers such as polystyrene, polyvinyl chloride, and ethylene terephthalate are known.

[0003]

SUMMARY OF THE INVENTION In a biological wastewater treatment method, in treating wastewater using a microorganism carrier, a method of separating the microorganism carrier and the treated water by a specific gravity difference using gravity as a means for separating the treated water, There is a method of separating a microorganism carrier and treated water by a separator such as a slit. Pellet-type plastic microbial carriers or hydrogels with solid contents have the disadvantage that even if microorganisms are immobilized by the inclusive method, for example, the inside is not used for water treatment but only part of the surface is used, and the specific surface area is large. Although the hollow microbial plastic microbial carrier described above is efficient, the use of ordinary plastic materials alone has the disadvantage of poor microbial adhesion and fixation.

[0004]

Means for Solving the Problems In view of the above problems, the present inventors have made intensive studies and found that a porous hollow tube or a pseudo-hollow tubular plastic substrate having a C-shaped cross section can be used.
A water-soluble polymer containing microorganisms is introduced into the pores, and then the microbial carrier produced through the step of insolubilizing the water-soluble polymer is a microbial carrier, a microbial carrier with a separator such as a slit. The present inventors have found that the separation of the treated water is excellent, and have accomplished the present invention.

[0005] The invention of claim 1 of the present invention is based on a porous hollow tube made of hydrophobic plastic or a pseudo hollow tubular material having a C-shaped cross section as a base material, and contains water containing microorganisms in the pores. A microorganism carrier into which a hydrophilic polymer has been introduced.

According to a second aspect of the present invention, there is provided the microorganism carrier according to the first aspect, wherein a water-soluble polymer containing a microorganism is introduced and then the water-soluble polymer is subjected to insolubilization treatment. .

The invention of claim 3 of the present invention is characterized in that the substrate of the microbial carrier made of a hydrophobic plastic is made of polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, epoxy resin or a derivative thereof. The microorganism carrier according to claim 1 or 2.

According to a fourth aspect of the present invention, there is provided the microorganism carrier according to any one of the first to third aspects, wherein the true specific gravity of the hydrophobic plastic microorganism carrier is 0.8 to 1.5. is there.

The invention of claim 5 of the present invention is characterized in that both the outer diameter and the tube length of the hydrophobic plastic microbial carrier are 3 m.
The microorganism carrier according to any one of claims 1 to 4, wherein the carrier is from m to 10 mm.

The invention according to claim 6 of the present invention is characterized in that the relationship between the outer diameter of the hydrophobic plastic microbial carrier and the size of the tube length is outer diameter ≧ tube length.
The microbial carrier described in 1. above.

The invention according to claim 7 of the present invention is characterized in that the type of the water-soluble polymer containing microorganisms is a hydrolyzate of N-vinylcarboxylic acid amide (co) polymer, a hydrolyzate of polyvinyl acetate, chitosan 7. The microorganism carrier according to claim 1, wherein the microorganism carrier is one selected from the group consisting of sodium alginate, sodium alginate, and a mixture thereof.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A first limitation of the present invention is that a porous hollow tube made of hydrophobic plastic or a pseudo hollow tubular material having a C-shaped cross section is used as a base material, and microorganisms are filled in the pores. A microorganism carrier into which a water-soluble polymer contained is introduced. The second limitation of the present invention is characterized in that the microorganism carrier according to claim 1 is subjected to an insolubilization treatment of the water-soluble polymer after introducing the water-soluble polymer containing the microorganism. A third limitation of the present invention is that in the microorganism carrier according to claim 1 or 2, the substrate of the hydrophobic plastic microorganism carrier is made of polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, epoxy resin or the like. Characterized by comprising a derivative of A fourth limitation of the present invention is claim 1
The microorganism carrier according to claim 3, wherein the true specific gravity of the hydrophobic plastic microorganism carrier is 0.8 to 1.5. A fifth limitation of the present invention is claim 1
The microorganism carrier according to claim 4, wherein the outer diameter and the tube length of the hydrophobic plastic microorganism carrier are both 3 mm to 10 mm. According to a sixth limitation of the present invention, in the microorganism carrier according to any one of claims 1 to 5, the relationship between the outer diameter and the tube length of the hydrophobic plastic microorganism carrier is such that outer diameter ≧ tube length. . A seventh limitation of the present invention is that in the microorganism carrier according to any one of claims 1 to 6, the type of the water-soluble polymer containing the microorganism is a hydrolyzate of an N-vinylcarboxylic acid amide (co) polymer. , A hydrolyzate of polyvinyl acetate, chitosan, sodium alginate, sodium polyacrylate, and a mixture thereof.

The skeletal material which guarantees the shape-retaining action of the microorganism carrier is referred to as a substrate. The term "hydrophobic substance" as used in the present invention refers to a general plastic material, that is, a water-insoluble and non-water-swellable material. It is a molecule. For example, polyethylene, polypropylene, polystyrene, polyvinyl chloride,
A substrate made of a plastic such as polyethylene terephthalate or epoxy resin or a waste plastic thereof is an object of the present invention. Since these substrates are water-insoluble and non-water-swellable, they have excellent durability in water and can be used stably for a long period of time. According to the wastewater treatment method envisioned by the present invention, the microorganism carrier to which microorganisms adhere is brought into contact with wastewater in a fluidized state, and then the microorganism carrier and treated water are separated by a separator such as a specific gravity difference or a slit lattice. The method of separating the microorganism carrier and the treated water by a separator such as a slit lattice is awarded because the separation speed can be increased, and the microorganism carrier of the present invention is a hollow tube or a pseudo hollow tube having a C-shaped cross section, so that a high specific surface area is obtained. Nevertheless, the separation is inherently easy because the dimensions and shape are large compared to the plastic of Muku. It is desirable that both the outer diameter and the tube length of the microbial carrier made of a hydrophobic plastic are 3 mm to 10 mm, and it is excellent in wastewater treatment ability by microorganisms and separation ability by a separator such as a slit lattice. Further, the relationship between the outer diameter of the hydrophobic plastic microbial carrier and the size of the tube length is preferably such that the outer diameter is equal to or greater than the tube length, and is excellent in clogging resistance and separation ability by a separator. The pores of the porous hydrophobic plastic microbial carrier into which the aqueous solution of the microorganism-containing water-soluble polymer is introduced are generated by the formation of ruptured air bubbles. The formation of the ruptured air bubbles is caused by mixing air bubbles into the plastic before molding and injection molding. Then, bubbles near the surface are ruptured and formed, and the type of gas into which the bubbles are mixed can be arbitrarily selected. The type of water-soluble polymer that forms the aqueous solution containing microorganisms is N-vinylcarboxylic acid amide (co)
It is characterized by being one selected from a hydrolyzate of a polymer, a hydrolyzate of polyvinyl acetate, chitosan, sodium alginate, sodium polyacrylate and a mixture thereof. N-vinylformamide or N-vinylacetamide is selected as N-vinylcarboxylic acid amide, and the hydrolysis is performed under hydrochloric acid conditions. The hydrolyzate of polyvinyl acetate is so-called polyvinyl alcohol. Chitosan is a hydrolyzate of crab and shrimp shells. These water-soluble polymers are used at a concentration of 1 to 10% and are used after being reduced in molecular weight so as to have a low viscosity of about 100 cp or less. The aqueous solution can be insolubilized by a conventional method using a crosslinking agent such as an aldehyde, boric acid, a polyvalent metal salt (Ca ⁺⁺ , M
g ⁺⁺ ) There is a method such as addition. The microorganisms contained in the aqueous solution may include ordinary microorganisms for BOD treatment, such as microorganisms for nitrogen removal treatment equipment such as nitrate bacteria, nitrite bacteria, nitrate reduction and denitrification bacteria. Because the microorganism carrier of the present invention has a high specific surface area, the fixed amount of microorganisms per unit weight of the microorganism carrier is large, and the fluidity of the microorganism carrier is high due to the high specific surface area,
It is suitable for a fluidized-bed aerobic biological treatment system, and has the advantage of being less likely to be clogged in a non-fluidized-bed biological denitrification treatment system. As described above, the microorganism carrier of the present invention is separated from the treated water by a specific gravity difference or a separator. When the separation is performed by a specific gravity difference, it is desirable that the specific gravity is slightly different from that of water. 0.8 to 1.5
Is desirable in terms of biological treatment properties and ease of separation. In the case of denitrification by nitrate reduction, nitrogen bubbles adhere and the apparent specific gravity of the microbial carrier is reduced, so that a specific gravity of 1 or more is superior in blocking resistance. When the separator separates the microbial carrier and the treated water, the specific gravity difference at the time of separation is irrelevant, and when it is not necessary to worry about bubble adhesion, the specific gravity of the microbial carrier is close to 1 and the energy required for flow is small. Help me.

[0014]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the scope of the examples. [Carrier] As a porous hollow tubular microbial carrier based on a substance made of a hydrophobic plastic, a polypropylene hollow tubular microbial carrier made porous by bursting bubbles (a cylindrical tube having an outer diameter of 4 mm, an inner diameter of 3 mm, and a tube length of 3 mm, The true specific gravity of 1.14) was subjected to a test as a microorganism carrier before filling with a microorganism-containing polymer aqueous solution. This is designated as carrier-0.
Hymoloc SC-7, which is a hydrolyzed hydrochloric acid of N-vinylformamide / acrylonitrile copolymer, was added to a suspension obtained by collecting denitrification sludge from a night soil treatment plant and adjusting it to 1% by weight of SS.
00 was dissolved in a polymer concentration of 5% by weight and mixed with 500 ppm of glutaraldehyde. A microbial-containing aqueous polymer solution was vacuumed and defoamed in contact with the carrier-0, and then returned to atmospheric pressure to empty the solution. The holes were filled. This microorganism carrier is referred to as carrier-1. The denitrification sludge from the night soil treatment plant was collected and adjusted to a SS of 1% by weight, and a microorganism-containing polymer aqueous solution obtained by dissolving chitosan hydrochloride at a polymer concentration of 5% by weight and mixing with glutaraldehyde at 500 ppm was added to a carrier-0. After defoaming by applying a vacuum in the state of contacting with, the pressure was returned to atmospheric pressure, and the liquid was filled in the pores. This microorganism carrier is referred to as carrier-2.

[Apparatus] A rotating shaft is provided at the center of an upright cylindrical tank having a diameter of 2.4 m and a height of 3.8 m. The rotating shaft is divided into nine equal parts from the vicinity of the bottom to a position of 3.5 m in height. At each position, a 65A stainless steel pipe having a length reaching the vicinity of the device wall is arranged so as to make a round of the circumference in a spiral step shape, and
It was rotated at 5 rpm by a Kw motor. The device has a wastewater inlet at the bottom and a treated water outlet at the top with a height of 4.
It has an edge screen of 0 cm slit width 2 mm,
A gas inlet is provided on the entire bottom of the device for backwashing.
As the next step of this apparatus, a contact oxidation tank filled with a honeycomb core was installed for the purpose of removing suspended microorganisms, BOD and phosphorus.

[Test-1] When subjecting the above apparatus to a wastewater treatment test, the carrier-0, carrier-
1, Carrier-2 was filled in an amount of 70 v / v% of the internal volume of the device and subjected to the test. A stainless steel quenching process wastewater (600 mg / l nitrate nitrogen, 2 mg / l phosphorus, PH7.
0) to nitrate nitrogen (nitrite): methanol = 1: 2.
The raw water added at a ratio of 4 was subjected to nitrate nitrogen loading of 2 kg /
m ³ . Supplied in days. The nitrate nitrogen concentration of the treated water was 580 ppm when Carrier-0 was used, Carrier-1 and Carrier-2.
It was 5 ppm or less when used. After one year, there is no wear of the carrier, and the wastewater treatment can be continued efficiently,
The durability of the carrier is high.

[0017]

The microorganism carrier of the present invention in which the pores are filled with microorganisms gives a rapid treatment start-up from the initial stage of operation, and efficiently maintains a wastewater treatment method using the same.
The cost is low and the economic effect is great.

Claims (7)

[Claims] 1. A porous hollow tube made of hydrophobic plastic or a pseudo hollow tubular material having a C-shaped cross section as a base material,
A microorganism carrier, wherein a water-soluble polymer containing a microorganism is introduced into the pores. 2. The microorganism carrier according to claim 1, wherein a water-soluble polymer containing a microorganism is introduced, and then the water-soluble polymer is insolubilized. 3. The method according to claim 1, wherein the substrate of the microbial carrier made of a hydrophobic plastic is made of polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, epoxy resin or a derivative thereof. Microbial carrier. 4. The microorganism carrier according to claim 1, wherein the true specific gravity of the hydrophobic plastic microorganism carrier is 0.8 to 1.5. 5. The microorganism carrier according to claim 1, wherein both the outer diameter and the tube length of the hydrophobic plastic microorganism carrier are 3 mm to 10 mm. 6. The microorganism carrier according to claim 1, wherein the relationship between the outer diameter and the tube length of the hydrophobic plastic microorganism carrier is such that outer diameter ≧ tube length. 7. The water-soluble polymer containing microorganisms may be selected from the group consisting of a hydrolyzate of an N-vinylcarboxylic acid amide (co) polymer, a hydrolyzate of polyvinyl acetate, chitosan, sodium alginate, and sodium polyacrylate. The microorganism carrier according to claim 1, wherein the microorganism carrier is one selected from the group consisting of: and a mixture thereof.