JP2002113483A - Microorganism carrier, and method and apparatus for treating wastewater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microorganism carrier for wastewater treatment excellent in water resistance and abrasion resistance and suitable for long-term use, and method and apparatus for treating wastewater using the microorganism carrier dispensing with replacement or replenishment and excellent in maintenance properties. SOLUTION: The microorganism carrier for wastewater treatment comprises a polynorbornene resin. In the wastewater treatment method, the carrier comprising the polynorbornene resin is used to biologically treat wastewater. The wastewater treatment apparatus has biological treatment part including the carrier comprising the polynorbornene resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microorganism carrier for wastewater treatment, a method and an apparatus for treating wastewater using the carrier.

[0002]

2. Description of the Related Art Various wastewaters such as human waste, sewage, domestic wastewater, and industrial wastewater are subjected to physical treatments such as screen, sedimentation, floating, filtration, etc .; chemical treatments such as neutralization, coagulation sedimentation, oxidation and reduction; The wastewater is purified in accordance with the properties of the wastewater by combining unit processes such as aerobic or anaerobic biological treatments such as a method, a biological filtration method, and a digestion method.

[0003] The pollutants contained in the wastewater are not always uniform, but generally, organic pollutants occupy most of the pollutants. In the treatment, usually, coarse impurities are removed by screens and sedimentation, and then colloidal substances are removed. After biological treatment of soluble organic matter and sterilization treatment, they are released into the environment such as rivers.

[0004] As a biological treatment method for wastewater, activated sludge method,
Many treatment methods such as biofilm filtration are known, but in recent years, the need for advanced treatment of effluent and the need for downsizing of equipment have increased, and it has become important to secure a large amount of microorganisms in the treatment tank. I have. Therefore, in order to increase the concentration of microorganisms, a carrier is charged or filled into the biological treatment tank, the carrier is immersed in the water to be treated, and the treatment is performed by microorganisms attached to the surface of the carrier, that is, a microorganism carrier. A wastewater treatment system using methane is considered to be advantageous.

[0005] Microbial carriers include sand, ceramics,
Inorganic carriers such as foam glass and foam concrete, polyurethane, polyester, vinyl chloride, polyethylene,
Various types are known, such as plastic carriers such as polypropylene and polystyrene (for example, JP-A-10-314783, JP-A-8-89987, JP-A-63-4899, JP-A-6-4899). 22
No. 6282, Japanese Patent Publication No. 1-56839).

[0006]

However, conventionally known microbial carriers each have advantages and disadvantages, and there are great restrictions on the apparatus in order to make the function of the carrier work well. For example, when the inorganic carrier is used in a fluidized state, the specific gravity is often too large to flow well. Further, when the apparatus is used in a stationary state, that is, on a fixed bed, the specific gravity is too large, and the power required for backwashing is significantly increased.

On the other hand, plastic carriers such as polyurethane and polyester have poor water resistance and cannot withstand long-term use. In addition, plastic carriers are generally susceptible to abrasion and abrasion because carriers collide with each other due to the flow of the carrier due to aeration, etc., and the carrier comes into contact with the walls of the processing equipment. Was necessary. Further, the wastewater treatment method and apparatus employing such a plastic carrier have problems in that maintenance and management are complicated and operating costs are increased.

An object of the present invention is to provide a microorganism carrier for wastewater treatment which has excellent water resistance and abrasion resistance and is suitable for long-term use. Another object of the present invention is to provide a wastewater treatment method and a wastewater treatment device using a microorganism carrier that does not require replacement or replenishment of the carrier and is excellent in maintainability.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies on the material of plastic used as a microorganism carrier and a wastewater treatment method. As a result, a polynorbornene-based resin obtained by bulk polymerization of a norbornene-based monomer was obtained. It has been found that the carrier is extremely hard to wear, has good adhesion of microorganisms, and has excellent swirl fluidity as a carrier for microorganisms. Furthermore, the wastewater treatment method and apparatus using the resin carrier have found that wastewater can be efficiently purified, and have completed the present invention.

That is, the microorganism carrier for wastewater treatment according to the present invention is characterized by comprising a polynorbornene-based resin.

The wastewater treatment method according to the present invention is characterized in that wastewater is biologically treated using a carrier made of a polynorbornene resin.

The wastewater treatment apparatus according to the present invention has a biological treatment section including a carrier made of a polynorbornene resin.

In the present invention, the biological treatment may be an aerobic treatment such as an activated sludge method or a biofiltration method, or may be an anaerobic treatment such as a digestion method. Not done.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the drawings. In the present embodiment, a combined treatment septic tank as an example of a wastewater treatment apparatus will be described. FIG. 1 is a schematic sectional view of a merged treatment septic tank according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line II-II of FIG.

[0015] As shown in combined treatment septic tank Figure 1, septic tank 2 according to the present embodiment is a combined treatment septic tank based on biological filtration system, septic tank body 4
Having. The material constituting the septic tank body 4 is not particularly limited, and may be polyethylene, polyvinyl chloride, polyester,
Examples include fiber reinforced plastic (FRP).
Preferably, it is composed of a polynorbornene-based resin obtained by a reaction injection molding method (RIM). In particular, it is preferable to be formed of a ring-opened polymer of a norbornene-based monomer modified with an elastomer. The septic tank body 4 is usually assembled by an upper tank body and a lower tank body.
The upper tank body, the middle tank body, and the lower tank body may be assembled.

The septic tank main body 4 is provided with three manholes 6 required for maintenance of the septic tank 2 along the longitudinal direction of the septic tank main body 4. A manhole cover (not shown) is attached to each manhole 6. An inflow port 8 for introducing wastewater (liquid to be treated) and a discharge port 10 for discharging purified water after treatment are formed at both ends in the longitudinal direction of the septic tank main body 4.

The inside of the septic tank main body 4 is divided into a plurality of processing tanks 20, 22, 24, 26, 28 by a plurality of partition plates 12, 14, 16 and a partition 18 along the longitudinal direction. In the present embodiment, from the upstream side where drainage is introduced,
An anaerobic filter bed first chamber 20, a anaerobic filter bed second chamber 22, a biological filtration tank 24, a treatment water tank 26, and a disinfection tank 28 are sequentially formed.

The first anaerobic filter bed tank 20 is a treatment tank into which drainage is introduced from the inflow port 8, and the second anaerobic filter tank second chamber 20 is provided.
The compartment 22 is partitioned from the chamber 22 by a partition plate 12, and the two chambers 2 are separated by a communication hole 122 formed above the partition plate 12.
0 and 22 are in communication. In the first chamber 20 of the anaerobic filter tank,
Anaerobic filter bed 2 with anaerobic bacteria attached to filter media such as synthetic resin
02 is supported and provided.

An anaerobic filter tank second chamber 22 adjacent to the anaerobic filter tank first chamber 20 is provided with a second anaerobic filter into which the liquid to be treated subjected to anaerobic treatment in the anaerobic filter tank first chamber 20 is introduced. It is a floor tank and is separated from the adjacent biological filtration tank 24 by the partition plate 14, and the two chambers 22 and 24 communicate with each other by a communication hole 142 opened in the upper part of the partition plate 14. Similarly to the anaerobic filter tank first chamber 20, the anaerobic filter tank second chamber 22 is also provided with an anaerobic filter bed 222 in which anaerobic bacteria adhere to a filter medium such as a synthetic resin.

The anaerobic filter bed 20 of the two chambers 20, 22 described above.
Anaerobic bacteria attached to 2,222 decompose organic matter in wastewater into organic acids such as acetic acid and propionic acid, which are further decomposed into methane gas and carbon dioxide gas. In addition, at least one of the two chambers 20 and 22 described above may be provided with a flow rate adjusting tank or a flow rate adjusting unit for mitigating fluctuations in the amount of inflow water.
May be a sedimentation separation tank or a contaminant removal tank without being filled with a filter medium.

The biological filtration tank 24 adjacent to the biological filtration layer anaerobic filter tank second chamber 22 is a processing tank into which the liquid to be treated, which has been subjected to further anaerobic treatment in the anaerobic filter tank second chamber 22, is introduced. Yes, adjacent treatment tank 2
6 is partitioned by a partition plate 16.
The two tanks 24 and 26 communicate with each other by a slot (small passage) 244b formed in the lower part of the tank.

As shown in FIG. 2, the biological filtration tank 24 according to the present embodiment includes a biological treatment section 24a and a filtration section 24.
b. In the present embodiment, these biological processing units 24a
The filtration unit 24b is disposed on the left and right in the horizontal direction substantially perpendicular to the longitudinal direction of the septic tank 2, but is not particularly limited thereto, and may be disposed on the front and rear along the longitudinal direction of the septic tank 2. Alternatively, they may be arranged vertically along the height direction of the septic tank 2. Biological treatment part 24a and filtration part 24b
Are connected by the advection tube 19 in the present embodiment, and the liquid to be treated from the biological treatment unit 24a flows into the filtration unit 24b through the communication hole 192 of the advection tube 19. Advection tube 19
Has a cross section in which a circle having a diameter of 150 mm or more can be inscribed in the present embodiment, but the cross section is not limited to a quadrangle but may be another shape.

The biological treatment section 24a is provided with a carrier layer 242a filled with a carrier to which aerobic bacteria are attached. The shape of the carrier filled in the carrier layer 242a is not particularly limited, and may be an irregular shape, or may be a dice shape, a cylindrical shape, or a pipe shape. Although the size of the carrier is not particularly limited, its maximum side length is usually 1 to 30 mm, preferably 2 to 25 mm, and more preferably 3 to 20 mm. In the present invention, such a carrier is composed of a polynorbornene-based resin. By forming the carrier with a polynorbornene-based resin, the flow when the liquid to be treated passes is improved, the water resistance, chemical resistance and abrasion resistance are excellent, and there is an advantage that periodic replenishment and replacement are not required. .

The polynorbornene resin can be obtained by reaction injection molding (RIM) of a reaction stock solution containing a metathesis catalyst and an activator in addition to the norbornene monomer.

As the norbornene-based monomer, cycloolefins having a norbornene ring such as dicyclopentadiene, dihydrodicyclopentadiene, tetracyclododecene, and tricyclopentadiene are preferred.

The metathesis catalyst may be any known metathesis catalyst as a catalyst for bulk polymerization of norbornene monomers such as organic ammonium molybdates such as tungsten hexachloride, tridodecyl ammonium molybdate and tri (tridecyl) ammonium molybdate. Although there is no particular limitation, ammonium organic molybdate is particularly preferred. In addition, as a metathesis catalyst, a known ruthenium carbene complex (WO97 / 06185, Japanese Patent Application Laid-Open No.
0-508891 and JP-A-11-329553) can also be applied.

Examples of the activator (cocatalyst) include alkyl aluminum halides such as ethyl aluminum dichloride and diethyl aluminum chloride, alkoxyalkyl aluminum halides thereof, and organotin compounds. When a ruthenium carbene complex is used as a metathesis catalyst, an activator may or may not be used.

The reaction stock solution may optionally contain a reinforcing material,
Various additives such as an antioxidant, a filler, an elastomer, a pigment, a colorant, a foaming agent, a flame retardant, a sliding agent, a dicyclopentadiene-based thermopolymerized resin and a hydrogenated product thereof may be blended.

The norbornene-based monomer is used by dividing into two or more reaction stock solutions. Specifically, a reaction stock solution (solution B) comprising a norbornene-based monomer containing a metathesis catalyst
And at least two reaction stock solutions comprising a reaction stock solution (solution A) comprising a norbornene-based monomer containing an activator. It is preferable that each of the liquid A and the liquid B is placed in a separate tank. Each of the reaction stock solutions alone does not cause polymerization of the norbornene-based monomer, but when each of the reaction stock solutions is mixed, bulk polymerization occurs. The sum of the components contained in each reaction stock solution corresponds to the amount of the components required for the bulk polymerization of the present invention. When performing bulk polymerization, two or more reaction stock solutions are instantaneously mixed using a mixing head or the like, and the mixed solution is immediately injected into a mold cavity to start polymerization. Then, the bulk polymerization in the cavity of the mold apparatus is completed, and the mold is opened when the molded body has solidified, whereby a molded body made of polynorbornene-based resin is obtained. The material and size of the mold to be used, the polymerization time during molding, the mold temperature, and other conditions may be the same as those of ordinary molding by bulk polymerization of polynorbornene-based resin.

In the present embodiment, the carrier is, for example,
(1) After obtaining a molded body made of a polynorbornene-based resin by the above-described method, the molded body may be pulverized and manufactured,
(2) A used resin molded article made of a polynorbornene-based resin (for example, a tank body of a septic tank or a waterproof pan) may be collected and crushed to be manufactured. The method of pulverizing the molded body includes a pulverizer generally used in industry (for example, an MHM type horizontal pulverizer (manufactured by Miike Iron Works), a PM type pulverizer, a PC1
A type 02 pulverizer (manufactured by Watanabe Steel) may be used. A molded product made of polynorbornene resin is continuously charged from the hopper of the crusher, and is crushed by impact cutting and crushing action of a fixed or suspended hammer attached to a high-speed rotating crusher main shaft, and the crushed material is crushed. By passing through the lower screen, the particles can be continuously discharged in a desired particle size. The pulverized material (carrier) obtained by such a method is
Since the surface has moderate irregularities, there is an advantage that microorganisms can be easily attached and fixed.

Further, the carrier may be produced by polymerizing (foam molding) a norbornene monomer in the presence of a foaming agent. Examples of the foaming means in this case include thermal expansion microcapsules, mechanical foaming with nitrogen gas or the like, and foaming under reduced pressure. By using such a foam molding method, there is an advantage that the specific gravity of the carrier can be adjusted or the specific surface area can be increased. In the case of producing a carrier, individual small carriers may be molded one by one, but from the viewpoint of production efficiency and handleability, a molded article made of a polynorbornene-based resin is molded once and then molded into a desired size. It is preferred to cut into small pieces or to continuously mold individual small carriers.

Although the true specific gravity of the polynorbornene resin constituting the carrier is 1.05, in the present invention, the specific gravity of the carrier can be arbitrarily set by the above-mentioned production method, addition of a specific gravity regulator, and the like. 7 to 1.5, preferably 0.8
To 1.3, more preferably 0.9 to 1.1. The specific gravity of the carrier, the closer the specific gravity of water, the better the fluidity,
If it is less than 0.7 or exceeds 1.5, the fluidity will be poor.

An aeration diffuser 244a for discharging air from an air supply port 246a to which a blower (not shown) is connected is disposed in the biological treatment section 24a. The air bubbles discharged from the aeration diffuser 244a to the inside of the biological treatment section 24a ensure the flow state of the carriers contained in the carrier layer 242a and prevent the carriers from being clogged. When the septic tank is operated, it is preferable that the aeration is always performed by the aeration diffuser 244a, but it is preferable that the aeration is stopped when performing the backwashing.

In the present embodiment, a filtration layer 242b filled with a carrier is also provided in the filtration section 24b similarly to the biological treatment section 24a.
Is provided. The material constituting the carrier filled in the filtration layer 242b is not particularly limited, for example, polyethylene,
Examples include polypropylene, polyurethane, ABS, PVC, and polynorbornene-based resin.

The filter 24b has an air supply port 248b (FIG. 1).
(See FIG. 2) is disposed. Spread bubbles discharged from the backwash air diffuser tube 246b into the inside of the filtration unit 24b can adhere to the carrier of the filtration layer 242b and peel off accumulated sludge (backwash step).

As shown in FIG. 1, the treated water tank 26 adjacent to the biological filtration tank 24 is a tank into which the liquid to be treated subjected to the aerobic treatment in the biological filtration tank 24 is introduced. Are partitioned by a partition 18, but the two chambers 26 and 28 communicate with each other through an upper portion of the partition 18. In the present embodiment, the treatment water tank 26 has a constant circulation transfer pipe 26.
2 is disposed, and a predetermined amount of the liquid to be treated existing at the bottom of the treated water tank 26 is measured by a measuring device 263 by an air lift pump (not shown) which is always operated, and is constantly anaerobic through a circulation transfer pipe 262. It can be sent to the filter bed tank first chamber 20. However, when performing the backwash, the circulation is always stopped. The treated water tank 26 is provided with a backwash water drain pipe 264 extending from the bottom of the treated water tank 26 to the bottom of the filtration unit 24b of the biological filtration tank 24, and is provided with an air lift pump (not shown). The backwash wastewater containing excess sludge separated and deposited in the inside 24 can be sent to the first anaerobic filter bed tank 20.

The disinfecting tank 28 adjacent to the treatment water tank 26 is an integrally formed small chamber to which a disinfectant is supplied by a chemical tube 282.

The effluent (liquid to be treated) which has flowed into the first chamber 20 of the anaerobic filter bed from the working inlet 8 is subjected to anaerobic treatment when passing through the anaerobic filter bed 202 by downward flow. It flows down to the second chamber 22 of the anaerobic filter tank through the 12 communication holes 122 by natural overflow of the weir.

The liquid to be treated that has flowed into the anaerobic filter bed second chamber 22 is subjected to further anaerobic treatment when passing through the anaerobic filter bed 222 by upward flow, and the communication holes 142 of the partition plate 14 are formed.
Through the biological treatment tank 24a of the biological filtration tank 24 by natural overflow. In the present embodiment, the anaerobic filter bed tank 2
The flow of the liquid to be treated in the chamber 22 is an upward flow, but is not limited thereto, and may be a downward flow.

The liquid to be treated that has flowed into the biological treatment section 24a is:
It passes through the carrier layer 242a by downward flow,
After a purification treatment (aerobic treatment) is performed by microorganisms adhering to the surface of the carrier flowing in the inside 2a, it flows into the upper part of the filtration part 24b through the communication hole 192 of the advection pipe 19. At this time, the flowing state of the carrier is ensured by the diffused bubbles discharged from the aeration diffuser 244a disposed at the bottom of the biological treatment section 24a. The liquid to be treated, which has flowed into the filtration unit 24b, is removed from the filtration unit 24b of the partition plate 16 (see FIG. 1) after the SS is removed when passing through the filtration layer 242b by the downward flow.
The water flows to the treated water tank 26 (see FIG. 1) through a slot 244b formed on the lower side. In the present embodiment, the flow of the liquid to be treated in the biological treatment section 24a and the filtration section 24b is a downward flow, but is not limited thereto.

The liquid to be treated that has flowed into the treated water tank 26 passes through the treated water tank 26, and the supernatant liquid that has passed through the partition 18 is transferred to the disinfecting tank 28 by natural overflow of the weir, and the disinfectant supplied by the chemical cylinder 282. After being chlorinated in
And discharged to the outside as discharge water. At the same time, the liquid to be treated existing at the bottom of the treated water tank 26 is always introduced into the measuring device 263 through the circulation transfer pipe 262, and after a predetermined amount is measured there, the anaerobic filter bed tank is always supplied through the circulation transfer pipe 262. It is sent to the first room 20.

On the other hand, when performing backwashing, the biological treatment section 24
The aeration from the aeration diffuser 244a arranged at the bottom of a is stopped. In addition, the constant circulation from the constant circulation transfer pipe 262 disposed at the bottom of the treatment water tank 26 to the anaerobic filter bed first chamber 20 is also stopped. In this state, the air bubbles are discharged from the backwash air diffuser 246b disposed at the bottom of the filtration unit 24b, and the excess sludge attached to the carrier of the filtration layer 242b of the filtration unit 24b is separated. Next, the backwash wastewater containing excess sludge separated and deposited in the filtration unit 24b passes through the backwash water drain pipe 264, which is disposed from the bottom of the treated water tank 26 to the bottom of the filtration unit 24b. It is sent to the first chamber 20 of the anaerobic filter tank at a water volume of 30 liter / min.

In the septic tank 2 according to this embodiment, the carrier layer 242a provided in the biological treatment section 24a of the biological filtration tank 24
Is made of a polynorbornene-based resin. A carrier made of a polynorbornene-based resin has many advantages such as excellent water resistance, chemical resistance and abrasion resistance, suitable for long-term use, and easy attachment of microorganisms. For this reason, according to the septic tank 2 of the present embodiment, there is no need to replace or replenish the carrier, and it is possible to achieve excellent maintenance.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments at all, and may be implemented in various modes without departing from the gist of the present invention. Of course.

For example, in the septic tank according to the above-described embodiment, five tanks 20, 22, 24, 26, and 28 are provided therein, but more tanks may be newly added. For example, a denitrification tank may be provided between the first anaerobic filter tank 20 and the second anaerobic filter tank 22. At a minimum, only one anaerobic filter tank is required.

[0046]

EXAMPLES Hereinafter, the present invention will be described based on more detailed examples, but the present invention is not limited to these examples.

Example 1 A styrene-isoprene-styrene block copolymer (Clayton) was used for 100 parts by weight of a mixed monomer composed of 85% by weight of dicyclopentadiene (DCP) and 15% by weight of an asymmetric cyclopentadiene trimer. 1170, manufactured by Shell Co., Ltd.) and 2 parts by weight of Irganox 1010 (Ciba Specialty Chemicals), which is a phenolic antioxidant, were dissolved in two containers. To one container, diethyl aluminum chloride (DEAC) was added to the mixed monomer in a concentration of 40 mmol, n-propanol in a concentration of 44 mmol, and silicon tetrachloride in a concentration of 20 mmol (Solution A).
In the other container, tri (tridecyl) ammonium molybdate was added to the mixed monomer so as to have a concentration of 10 mmol (Solution B). The thus prepared solution A and solution B were sent to the mixing head by a gear pump so as to have a volume ratio of 1: 1. Next, the mixture was injected into the mold at a mold temperature of 70 ° C. and an injection pressure of 0.2 MPa or less, and then a bulk polymerization reaction was performed in the mold for 3 minutes. These series of operations were performed under a nitrogen atmosphere.
Thereafter, the molded product was removed from the mold to obtain a cylindrical (about 10 mm in diameter × about 15 mm in height) polynorbornene-based resin carrier. When the specific gravity of the obtained carrier was measured, it was 1.03.

After producing a plurality of such carriers, they are put into a 300 ml polyethylene container together with the predetermined liquid shown in Table 1 so that the filling rate becomes 62.5%, and at room temperature, the contents of Table 1 are reduced. For a predetermined period as shown in (1), using a shaker (product number V-SX, manufactured by Iwaki Co.). Thereafter, the carriers were taken out of the polyethylene container, and these were heated to 80 ° C.
And the weight change (weight loss rate) of the total weight W2 after shaking with respect to the total weight W1 before shaking was calculated by the following equation. Table 1 shows the results.

Weight loss rate (%) = {(W1-W2) / W1} × 100 Comparative Example 1 A plurality of cylindrical polypropylene carriers (product number Biostage manufactured by Tsutsunaka Plastics Industry Co., Ltd.) of the same size as in Example 1 The weight change before and after shaking was calculated in the same manner as in Example 1 except that the number of pieces was used. Table 1 shows the results.

Comparative Example 2 Example 1 was repeated except that a plurality of dice-shaped sponge-like polyethylene carriers (open cells, size: about 10 mm × about 10 mm, manufactured by Hitachi Chemical Co., Ltd., product number KGF-2) were used. Similarly, the weight change before and after shaking was calculated. Table 1 shows the results.

Comparative Example 3 Dice-shaped sponge-like urethane carrier (20-fold foaming,
Weight change before and after shaking was calculated in the same manner as in Example 1 except that a plurality of sizes: about 10 mm × about 10 mm (manufactured by Inoac Corporation) were used. Table 1 shows the results.

[0052]

[Table 1]

As shown in Table 1, the following is understood with respect to water resistance, chemical resistance and abrasion resistance.

As for the water resistance (water), Comparative Example 1 showed a water resistance of 0.1%.
1%, 4.2% in Comparative Example 2 and 6.9% in Comparative Example 3 were 0.1% in Example 1, and the carrier of Example 1 was water-resistant (also abrasion-resistant). Including).

Chemical resistance (HNO₃, NaOH, NH
₃, NaHClO, and a neutral detergent) in Comparative Example 1
Showed relatively good resistance to all chemicals
However, there is a tendency that the resistance to NaOH is slightly deteriorated.
You. Comparative Example 2 has almost the same weight for all chemicals
Changes, especially HNO₃And NaHClO
There was a tendency for the resistance to the drug to slightly deteriorate. Comparative Example 3
Is especially HNO₃, NH₃ , Resistance to NaHClO
Got worse. On the other hand, in Example 1,
The reduction rate is 0.7% or less with respect to
Ensure that the body is excellent in chemical resistance (including abrasion resistance)
It was recognized.

Compiling the above test results of water resistance, chemical resistance and abrasion resistance (see Table 1), the polynorbornene resin carrier of Example 1 is made of polypropylene and polystyrene of Comparative Examples 1 to 3. It was confirmed to be superior to various urethane carriers.

Note that HNO ₃ , NaOH, NH ₃ ,
Since NaHClO and the neutral detergent are likely to flow into a septic tank as an example of a wastewater treatment device, they were included in the target liquid. HNO ₃ was included because when organic matter is decomposed in the septic tank, it is generated.

[0058]

As described above, according to the present invention, it is possible to provide a microorganism carrier for wastewater treatment which has excellent water resistance and abrasion resistance and is suitable for long-term use. Further, according to the present invention, it is possible to provide a wastewater treatment method and a wastewater treatment apparatus using a microorganism carrier which does not require replacement or replenishment of the carrier and has excellent maintainability.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a merged treatment septic tank according to one embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

[Explanation of symbols]

 2 ... Merged treatment septic tank (drainage treatment device) 4 ... Septic tank main body 6 ... Manhole 8 ... Inflow port 10 ... Discharge port 12, 14, 16 ... Partition plate 122, 142, 192 ... Communication hole 18 ... Partition wall 19 ... Advection pipe 192 ... Communication hole 20 ... Anaerobic filter bed first chamber 202 ... Anaerobic filter bed 22 ... Anaerobic filter tank second chamber 222 ... Anaerobic filter bed 24 ... Biological filtration tank 24a ... Biological treatment section 242a ... Carrier layer 244a ... Aeration Air diffuser 246a Air supply port 24b Filtration unit 242b Filtration layer 244b Slot (small passage) 246b Back diffuser 248b Air supply port 26 Processing water tank 262 Continuous circulation transfer pipe 263 Measuring device 264 Backwash water drain pipe 28 ... Disinfection tank 282 ... Chemical tube

Claims (3)

[Claims] 1. A microorganism carrier for wastewater treatment comprising a polynorbornene-based resin. 2. A wastewater treatment method comprising subjecting wastewater to biological treatment using a carrier made of a polynorbornene-based resin. 3. A wastewater treatment apparatus having a biological treatment section including a carrier made of a polynorbornene-based resin.