JPH11290069A - Microorganism support - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a microorganism-carrying support that can perform the efficient waste water treatment from the initial stage of the operation and has increased cell anchorage of the microorganism, high strength and contaminated water-cleaning properties by introducing a water-soluble polymer containing the microorganism into the voids of the base material of the support that is a cellulosic substance with a tetrahedron shape or the like. SOLUTION: A microorganism-containing water-soluble polymer selected from a hydrolyzate of N-vinylcarboxylic amide (co)polymer, hydrolyzate of poly(vinyl acetate), chitosan, sodium alginate and their mixture is introduced into the voids of a porous cellulosic base material that has a shape of tetrahedron, prism or cube, and is made of a cellulosic substance as a precipitate of soluble cellulose of the true specific gravity of 1.2-1.4 and the size of 3-10 mm. It is preferred that this water-soluble polymer is subjected to insolubilization treatment after introduction of the water-soluble polymer.

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. It is related to a cellulose microbial carrier effective for purifying contaminated water by a treatment device,
It is 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 apparatuses that use wastewater containing nitrate nitrogen such as nitrogen with organic substances such as methanol for the denitrification reaction by reduction, etc., are known, such as hydrogels composed of various cross-linked resins, and microbial carriers made of cellulose. It has been 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. The hydrogel has a weak mechanical strength and has a disadvantage that it is easily broken down when microorganisms are fixed and used by the entrapment method. In addition, the conventional cellulose carrier made of cellulose has a drawback that the adhesion and fixation of microorganisms is poor.

[0004]

Means for Solving the Problems In view of the above problems, the present inventors have made intensive studies and as a result, have found that a porous material made of a cellulose material and having a shape selected from a triangular pyramid, a prism or a cube is used. The microorganism carrier produced through the step of introducing a water-soluble polymer containing microorganisms into the pores, and then performing a process of insolubilizing the water-soluble polymer, has a microorganism fixing property, mechanical strength, slit, etc. It has been found that the separator of the present invention has an excellent effect on the separation of the microorganism carrier and the treated water, and the present invention has been accomplished.

[0005] The invention of claim 1 of the present invention relates to a porous material having a shape selected from a triangular pyramid, a prism or a cube, made of a cellulosic material, and containing a microorganism containing water 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. .

According to a third aspect of the present invention, there is provided the microorganism carrier according to any one of the first to second aspects, wherein the porous substrate of the microorganism carrier comprises a precipitate of dissolved cellulose.

[0008] The invention according to claim 4 of the present invention is characterized in that the true specific gravity of the substrate of the porous microorganism carrier is 1.2 to 1.4. It is a microbial carrier.

The invention according to claim 5 of the present invention is the microorganism carrier according to any one of claims 1 to 4, characterized in that the size of the porous microorganism carrier substrate is 3 mm to 10 mm on each side. .

The invention according to claim 6 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 6. 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.

[0011]

DETAILED DESCRIPTION OF THE INVENTION A first limitation of the present invention is that a triangular pyramid,
A microbial carrier having a shape selected from prisms or cubes, comprising a porous substance made of a cellulose substance as a base material, and a water-soluble polymer containing a microorganism introduced into the pores. A second limitation of the present invention is claim 1
The microorganism carrier according to the above, wherein a water-soluble polymer containing a microorganism is introduced, and then the water-soluble polymer is insolubilized. A third limitation of the present invention is claim 1
The microorganism carrier according to claim 2, wherein the porous substrate of the microorganism carrier is composed of a precipitate of dissolved cellulose. A fourth limitation of the present invention is that in the microorganism carrier according to any one of claims 1 to 3, the true specific gravity of the porous microorganism carrier is 1.2 to 1.4. . A fifth limitation of the present invention is characterized in that in the microorganism carrier according to any one of claims 1 to 4, the size of the substrate of the porous microorganism carrier is 3 mm to 10 mm on each side. A fifth limitation of the present invention is claim 1
5. The microorganism carrier according to claim 4, wherein 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, or alginic acid. It is one kind selected from soda, sodium polyacrylate and a mixture thereof.

A skeletal material which guarantees the shape-retaining action of the microorganism carrier is called a substrate. The porous cellulose material as the substrate in the present invention is a cellulose xanthate solution, that is, a viscose solution or a foaming agent such as calcium carbonate. Is produced by contact-precipitating with an aqueous solution of an acid-containing salt, followed by cutting and molding with a saw or the like. 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 using 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 porous, and therefore has a large size and shape despite its high specific surface area. And the separation is essentially easy. One side of the microbial carrier made of the porous cellulose material is 3 mm to 10 mm.
mm, it is excellent in wastewater treatment ability by microorganisms and separation ability by a separator such as a slit lattice. The types of water-soluble polymers that form the microorganism-containing aqueous solution include N-vinylcarboxylic acid amide (co) polymer hydrolyzate, polyvinyl acetate hydrolyzate, chitosan,
It is one selected from 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
It is used after being reduced in molecular weight so as to have a low viscosity of about p or less.
The aqueous solution can be insolubilized by a conventional method such as a crosslinking agent such as an aldehyde, boric acid, or a polyvalent metal salt (Ca ⁺⁺ , Mg ⁺⁺ ). The microorganisms contained in the aqueous solution are nitric acid bacteria,
It may include microorganisms for nitrogen removal treatment equipment such as nitrites and nitrate reduction / denitrification bacteria, as well as ordinary microorganisms for BOD treatment.
Since 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, which is suitable for a fluidized bed aerobic biological treatment system, In addition, there is an advantage that clogging hardly occurs even in the non-fluidized bed type biological denitrification treatment system. As described above, the separation of the microorganism carrier of the present invention from the treated water is separated by a specific gravity difference or a separator, and when the separation is performed by the specific gravity difference, it is desirable that the specific gravity is slightly different from that of water. A ratio of 1.2 to 1.4 is desirable in terms of biological treatment characteristics 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 microorganism carrier and the treated water are separated by the separator, the specific gravity difference at the time of separation is irrelevant, and when it is not necessary to care about the adhesion of bubbles, the specific gravity of the microorganism carrier is 1
The energy required for the flow to be close to is small.

[0013]

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 microbial carrier substrate made of porous cellulose, a microbial carrier manufactured by Toshin Electric Co., Ltd., trade name: 3mAQUAC
EL (5 to 8 mm cube per side, true specific gravity 1.24) was used as a microbial carrier before filling with the aqueous microbial polymer solution. This is designated as carrier-0. Hymoloc SC-700, a hydrochloric acid hydrolyzate of N-vinylformamide / acrylonitrile copolymer, was added to a suspension having the denitrification sludge collected from the night soil treatment plant and adjusted to 1% by weight of SS, at a polymer concentration of 5%.
A microbial-containing polymer aqueous solution, which was dissolved in wt% and mixed with glutaraldehyde (500 ppm), was degassed by applying a vacuum in a state in which it was in contact with the carrier-0, and then returned to the atmospheric pressure to fill the pores. 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, and the rotating shaft is divided into nine equal parts from a position near the bottom to a position having a height of 3.5 m. 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 above carriers 0 and 0 were used as microorganism carriers.
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 three months, the carrier was not worn and the durability was very high.

[0016]

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 (6)

[Claims] Claims 1. A water-soluble polymer containing microorganisms having a shape selected from a triangular pyramid, a prism or a cube, and made of a porous material made of a cellulosic material and having pores therein. Microbial carrier characterized. 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 microorganism carrier according to claim 1, wherein the porous substrate of the microorganism carrier comprises a precipitate of dissolved cellulose. 4. The microorganism carrier according to claim 1, wherein the true specific gravity of the porous microorganism carrier substrate is 1.2 to 1.4. 5. The microorganism carrier according to claim 1, wherein the size of the porous substrate of the microorganism carrier is 3 mm to 10 mm on a side. 6. The type of the water-soluble polymer containing a microorganism is a hydrolyzate of an N-vinyl carboxylic acid amide (co) polymer, a hydrolyzate of polyvinyl acetate, chitosan, sodium alginate, 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.