JP2009000675A - Bulking eliminating agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bulking eliminating agent which can be adapted to various causes to eliminate bulking without exerting an influence on useful microorganisms in activated sludge. <P>SOLUTION: The bulking eliminating agent contains a water-soluble cationic polymer having a monomer unit represented by Formula (1) and (2) as an effective component. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bulking remover.

  In the activated sludge treatment method for organic wastewater, the wastewater is mixed with activated sludge in the aeration tank (hereinafter sometimes simply referred to as “sludge”) and aerated, and then solid-liquid separation tanks such as sludge settling tanks and levitation tanks. The sludge is separated and the separated liquid is discharged as treated water, while part of the separated sludge is returned to the aeration tank as return sludge and the rest is discharged as surplus sludge. In such an activated sludge treatment method, it is said that organic matter is decomposed by flocs (activated sludge) in which various microorganisms gather, centering on a group of bacteria called zoom glare, but depending on the properties of organic wastewater and various treatment conditions. In the solid-liquid separation tank, the sludge becomes poorly separated, or a phenomenon occurs in which sludge is entrained and floats in the aeration tank or the sedimentation tank. In the present invention, these sludge poor separation and sludge floating phenomenon are collectively referred to as bulking. When bulking occurs, the sludge interface rises, the sludge rises, and in some cases, the sludge may carry over without being completely separated in the solid-liquid separation tank.

  Possible causes of bulking include, for example, the sedimentation of the sludge flocs being degraded, the microorganisms in the activated sludge no longer form flocs, the microorganisms in the activated sludge generate viscous substances, and the solid-liquid separation properties deteriorate The sludge becomes low in specific gravity due to oil, actinomycetes, etc., making it difficult to settle in the sedimentation tank, or the sludge becomes high in specific gravity and difficult to float in the levitation tank. There are various factors such as sludge swelling and deterioration of solid-liquid separation, swollen sludge entraining bubbles and floating in an aeration tank or settling tank.

  Once activated sludge causes bulking, it is not easy to restore its function, and it may be necessary to replace the sludge. In such cases, the factory must stop operation during the sludge acclimatization period. No longer. In addition, if sludge flows out, it pollutes the environment, and the sludge concentration decreases, thereby removing BOD (Biochemical Oxygen Demand) and / or COD (Chemical Oxygen Demand). Efficiency may be reduced, leading to environmental pollution.

Therefore, as a countermeasure against bulking, for example, a method of performing anaerobic aerobic treatment without depending on the addition of chemicals, a normal microflora is restored only by operating conditions such as shortening the SRT (active sludge residence time), A method for obtaining activated sludge without bulking (for example, see Patent Document 1), a method for eliminating bulking by adding a bactericidal agent such as chloride or surfactant to filamentous bacteria (for example, Patent Document 2, 3), a method of eliminating bulking by adding a flocculant such as a cationic polymer flocculant or an inorganic flocculant (see, for example, Patent Document 4), sludge having a low specific gravity by adding a flocculant and glass powder. (For example, see Patent Document 5), a method for eliminating bulking by adding a group of microorganisms having an action of lysing filamentous bacteria to a treatment tank of activated sludge (see, for example, Patent Document 6) ), And the like have been proposed.
JP 50-47459 A JP-A-6-63580 JP-A-8-103788 JP-A-10-244287 JP 2006-130458 A Japanese Patent Laid-Open No. 3-154696

However, as described in Patent Document 1, it is necessary to spend several weeks in the method of returning to a normal microflora only by operating conditions.
Moreover, as described in Patent Documents 2 and 3, in the method of adding a bactericide, not only filamentous bacteria but also useful microorganisms in the activated sludge are killed, and the activated sludge may be dismantled.
Furthermore, as described in Patent Documents 4 and 5, although the method of adding a flocculant has a temporary effect because the activated sludge is forced to settle, it has a fundamental effect on eliminating abnormal growth of filamentous bacteria. It did not come to a solution. Moreover, since the microorganisms in the activated sludge are aggregated to form a large floc, there is a problem that the microorganism activity decreases.
In addition, as described in Patent Document 6, in the method of adding a group of microorganisms that lyse filamentous bacteria, it was difficult to cause these microorganism groups to specifically act on filamentous bacteria in activated sludge.
As described above, the conventional methods have many technical problems, and no method that can eliminate bulking by adapting to various causes has been known.

  The present invention has been made in view of the above circumstances, and aims to realize a bulking eliminating agent that can eliminate bulking by adapting to various causes without affecting useful microorganisms in activated sludge. .

  The bulking eliminating agent of the present invention is characterized by containing, as an active ingredient, a water-soluble cationic polymer having monomer units represented by the following formulas (1) and (2).

  In addition, the water-soluble cationic polymer contains 1 to 99.9 mol% of the monomer unit represented by the above formula (1) as a repeating unit and the monomer unit represented by the above formula (2). It is preferable to contain 0.1-99 mol% as a repeating unit, and the reduced viscosity in 25 degreeC at the time of setting it as a 0.1 g / dL solution with 1N salt solution is 0.01-15 dL / g.

ADVANTAGE OF THE INVENTION According to this invention, the bulking elimination agent which can eliminate a bulking by adapting to various causes, without affecting the useful microorganisms in activated sludge is realizable.
In addition, according to the bulking-removing agent of the present invention, bulking caused by a wide variety of causes such as activated sludge dismantling or flock formation failure, viscosity, filamentous bacteria, low specific gravity, etc. Can be resolved. In particular, bulking caused by at least one kind of filamentous bacteria in the activated sludge can be more effectively eliminated.

Hereinafter, the present invention will be described in detail.
[Bulking remover]
The bulking eliminating agent of the present invention contains a water-soluble cationic polymer as an active ingredient.

  The water-soluble cationic polymer has monomer units represented by the following formulas (1) and (2).

  The method for producing such a water-soluble cationic polymer is not particularly limited. For example, N-methoxyethylformamide obtained by reacting acetaldehyde, formamide and methanol is thermally decomposed into N-vinylformamide and methanol. It can be produced by polymerizing the obtained N-vinylformamide and hydrolyzing the formyl group of the resulting poly-N-vinylformamide.

  As a polymerization method for N-vinylformamide or the like, a normal radical polymerization method is used, and any of bulk polymerization, aqueous solution polymerization, suspension polymerization, emulsion polymerization, and the like can be used. When polymerizing in a solvent, the raw material monomer concentration is usually 5 to 80% by mass, preferably 20 to 60% by mass. A general radical polymerization initiator can be used as the polymerization initiator, but an azo compound is preferable, and a hydrochloride of 2,2'-azobis (2-amidinopropane) is exemplified. The polymerization reaction is generally performed at a temperature of 30 to 100 ° C. under an inert gas stream. The obtained polymer can be hydrolyzed as it is or diluted, that is, in the form of a solution or suspension.

As the hydrolysis method, a known method can be used. For example, an acid or alkaline aqueous solution is added to an aqueous solution of the polymer, and the temperature is usually 20 to 120 ° C., preferably 30 to 90 ° C., usually 0. By heating for 1 to 24 hours, a solution of a water-soluble cationic polymer in which at least a part of the formyl group in the polymer is split and released is obtained.
The obtained water-soluble cationic polymer solution may be used as a bulking-eliminating agent as it is, and a dry or insoluble solvent (for example, acetone) is added to precipitate the water-soluble cationic polymer, and the solid After being taken out as a water-soluble cationic polymer, it may be dissolved in water or the like at the time of use.

 Most typically, the water-soluble cationic polymer used in the present invention is obtained by polymerizing N-vinylformamide in water, as described above, and heating the resulting polymer in the presence of an alkali. Then, it is preferably produced by hydrolysis to form monomer units represented by the above formulas (1) and (2). And the water-soluble cationic polymer of various compositions is obtained by selecting the molar concentration of N-vinylformamide to be subjected to polymerization, polymerization conditions, hydrolysis conditions, and the like.

The water-soluble cationic polymer thus obtained is 1 to 99.9 mol% with the monomer unit represented by the above formula (1) as a repeating unit in 100 mol% of the water-soluble cationic polymer. It is preferable to contain, More preferably, it is 10-99.9 mol%. If the content is less than 1 mol%, the content of vinylamine units is too small, so the effect as a bulking remover is weak, and the amount used is increased when using the bulking remover. On the other hand, it is difficult to produce a product whose content exceeds 99.9 mol% by the above-described method.
Moreover, it is preferable to contain 99-0.1 mol% of monomer units represented by the said Formula (2) as a repeating unit in 100 mol% of water-soluble cationic polymers, More preferably, it is 90-0. 1 mol%. If the content is less than 0.1 mol%, it is difficult to produce by the method described above. On the other hand, when the content exceeds 99 mol%, the effect as a bulking eliminating agent is weak, and the amount of the bulking eliminating agent used is increased.

The water-soluble cationic polymer may contain other monomer units other than the monomer units represented by the above formulas (1) and (2).
Examples of other monomer units include acrylonitrile, acrylamide, and acrylic acid, and these monomer units may be copolymerized during the polymerization of N-vinylformamide.

The composition of the monomer units represented by the above formulas (1) and (2) and other monomer units were measured by ¹³ C-NMR ( ¹³ C-nuclear magnetic resonance) of a water-soluble cationic polymer. Specifically, it can be calculated from the integrated value of the peak (signal) of the ¹³ C-NMR spectrum corresponding to each repeating unit.

The bulking-eliminating agent of the present invention may consist only of the above-mentioned water-soluble cationic polymer, but contains the water-soluble cationic polymer as an active ingredient and contains other components as long as the performance is not impaired. It may be used in combination with other bulking agents.
Examples of other components include formic acid and ammonium chloride.
Examples of other bulking agents include polyacrylic acid esters and benzethonium chloride.
In the present invention, the “active ingredient” means the content of the water-soluble cationic polymer in 100% by mass of the bulking canceling agent, and it is usually preferable to contain 10 to 100% by mass.

  When the bulking agent contains other components, other components may be added so that the desired blending amount is obtained after the water-soluble cationic polymer is produced. Other components may be mixed.

  The bulking-removing agent thus obtained preferably has a reduced viscosity at 25 ° C. of 0.01 to 15 dL / g, more preferably 0.1 g / dL in 1N saline. Is 0.05 to 10 dL / g, particularly preferably 0.1 to 10 dL / g. When the reduced viscosity is less than 0.01 dL / g, it tends to be difficult to produce a bulking remover, or the function of the bulking remover tends to decrease. On the other hand, when the reduced viscosity exceeds 15 dL / g, the viscosity of the bulking-removing agent becomes too high, resulting in inconvenience in handling when added to an aqueous solution in which bulking has occurred.

The reduced viscosity described above can be controlled by adjusting the molecular weight, ionic ratio, molecular weight distribution, production method, composition distribution, and the like of the bulking remover.
For example, when the molecular weight of the bulking remover is increased, the reduced viscosity tends to increase.

[Usage of bulking agent]
The bulking-eliminating agent of the present invention may be used by adding it to activated sludge in advance (pre-addition), or may be used after adding bulking to an aeration tank or a solid-liquid separation tank (post-addition). If a bulking remover is added to activated sludge in advance, bulking can be prevented without adversely affecting the activated sludge.

(Pre-addition)
When the bulking eliminating agent is added to the activated sludge in advance, the addition amount of the bulking eliminating agent is preferably 0.0001 to 25 parts by mass, more preferably 0.0001 to 10 parts by mass with respect to 100 parts by mass of the dry solid content of the activated sludge. preferable. When the addition amount is less than 0.0001 part by mass, it becomes difficult to sufficiently obtain the effect of the bulking eliminating agent. On the other hand, when the addition amount exceeds 25 parts by mass, there is a possibility of adversely affecting the microbial activity in the activated sludge.

  In the present invention, “added to activated sludge” means to be added to any place in the activated sludge treatment system and brought into contact with microorganisms in the activated sludge. For example, it is added to the raw water tank together with the activated sludge. To the aeration tank, added directly to the aeration tank, added directly to the solid-liquid separation tank such as the activated sludge settling tank and levitation tank, and the oxygen-free tank at the facility where there is an oxygen-free tank for the purpose of denitrification, etc. In addition to direct addition, any addition method may be used as long as it has an effect of eliminating bulking. Further, it can be added to a flow path such as a side groove or a pipe connecting the tanks or a flow rate adjusting tank provided in front of each tank.

  However, even when the bulking-eliminating agent of the present invention is brought into contact with microorganisms in activated sludge, for example, it is used for the purpose of promoting solid-liquid separation and dehydration of surplus sludge that is discarded in its entirety, and the bulking-eliminating agent is When not flowing into the aeration tank, it is different from the gist of the present invention to realize a bulking solution that can be applied to various causes without adversely affecting useful microorganisms in the activated sludge. Absent. However, even in such a case, when a part of the solid-liquid separation tank is returned to the aeration tank or used to eliminate sludge floating in the upstream aeration tank, etc., the effects of the present invention can be obtained. It is within the scope of the present invention.

(Post-addition 1)
When bulking agent is added after bulking has occurred, sludge separation is particularly difficult in solid-liquid separation tanks due to disintegration of activated sludge, poor flock formation, generation of viscous substances, and low or high specific gravity of sludge. Is usually added directly to the solid-liquid separation tank or dissolved in water or the like, or injected into a sludge line flowing into the solid-liquid separation layer and led to the solid-liquid separation layer. Good.

Although the usage-amount of a bulking cancellation agent changes with kinds of activated sludge, it is not specifically limited, For example, 0.0001-10 mass parts is preferable with respect to 100 mass parts of dry solid content of activated sludge.
The amount of bulking agent used is collected in a beaker of sludge that causes bulking, added to the bulking agent, and SV30 (activated sludge sedimentation rate) (Japan Sewerage Association, “Sewerage Testing Method”). It can also be determined by evaluating the turbidity (JIS K 0102) of the upper volume 1997 edition "p271), the supernatant.

The bulking eliminating agent according to the present invention can be used in combination with other bulking eliminating agents, and agents having a sedimentation promoting effect such as inorganic flocculants and polymer flocculants.
If sedimentation is poor in the sedimentation tank due to the low specific gravity of the sludge, the above-mentioned amount of bulking eliminating agent may be added, but if a high specific gravity substance is added at the same time, bulking is more effective. Can be eliminated.
Substances with high specific gravity include, for example, zeolite, diatomaceous earth, activated carbon, incinerated ash, clay minerals, insoluble solid powders such as glass, iron, aluminum, water glass, etc. It is possible to use a soluble substance or the like having a water content, and the amount used may be appropriately adjusted together with the bulking remover according to the activated sludge.

Moreover, if the sludge becomes a high specific gravity due to the high specific gravity, the above-mentioned amount of bulking eliminating agent may be added, but it is more effective if a low specific gravity substance is added at the same time. Can eliminate bulking.
For example, neutral oils with an ester structure made from plants, animals, minerals, and acidic oils such as phospholipids can be used as low-density materials. The amount used is bulking according to the activated sludge. What is necessary is just to adjust suitably with a cancellation agent.

The bulking-eliminating agent of the present invention has the effect of binding flocs and microorganisms without reducing the microbial activity in the activated sludge, so it is especially added to the bulking caused by disintegration of activated sludge and poor floc formation. Then, since the floc becomes large, sedimentation is promoted and bulking is quickly eliminated.
In addition, the bulking-removing agent has a remarkable effect of reducing the viscosity of the viscous substance. Therefore, when added to the bulking generated due to the generation of the viscous substance, the solid-liquid separation property is improved and the bulking is quickly eliminated. .

In addition, the bulking-removing agent has the effect of binding the part with low specific gravity to the part with high specific gravity, so when added to bulking, which is caused by low specific gravity due to oil or actinomycetes, sludge sedimentation. Defects are reduced and bulking is eliminated. Further, since the bulking eliminating agent has an action of binding a high specific gravity such as mineral to sludge having a low specific gravity, for example, if it is added together with mineral, it is possible to effectively eliminate the sedimentation failure in the sedimentation tank.
Due to the high specific gravity of sludge due to the same action, even if only the high specific gravity part does not float during floating separation such as normal pressure and pressurized flotation, if bulking solution is added, bulking will be reduced. Can be resolved. Moreover, if it is added together with a low specific gravity such as oil, for example, it is possible to effectively eliminate the floating failure in the floating tank.

(Post-addition 2)
When a bulking agent is added after bulking has occurred, especially when sludge separation is poor in a solid-liquid separation tank due to filamentous bacteria, it can be added to all tanks in which filamentous bacteria have been generated. It is desirable because it can kill more bacteria and eliminate bulking in a short time.
The killing effect on the propagated filamentous bacteria appears in minutes to hours after adding the bulking-removing agent. Cell damage can be observed under a microscope, such as leakage of objects or bending of cells.
The bulking-eliminating agent of the present invention has the effect of enlarging the reduced flocs by killing filamentous bacteria, resulting in accelerated solid-liquid separation, eliminating bulking, and bringing activated sludge into a normal state. Recover.

Although the usage-amount of a bulking elimination agent changes with kinds of activated sludge, it is not specifically limited, For example, 0.1-25 mass parts is preferable with respect to 100 mass parts of dry solid content of activated sludge.
The amount of bulking agent used is collected in a beaker of sludge that causes bulking, added to the bulking agent, and SV30 (activated sludge sedimentation rate) (Japan Sewerage Association, “Sewerage Testing Method”). It can also be determined by evaluating the turbidity (JIS K 0102) of the upper volume 1997 edition "p271), the supernatant. Furthermore, if necessary, it can also be determined by observing cell cutting (floating matter) or cell damage with a phase contrast microscope or the like.
In addition, when the swollen sludge is entrained with air bubbles and floats in an aeration tank or settling tank, the activated sludge collected in a beaker or the like is aerated using a small air diffuser, etc., and the sludge floats before and after the bulking solution is added. The amount used can be determined by evaluating the degree.

  The bulking eliminating agent of the present invention can kill filamentous bacteria in a short time. In that case, since it also has the effect | action which accelerates | stimulates the solid-liquid separation of the fragmented microbial cell and a cell residue, the solid-liquid separation property of activated sludge is synergistically improved by addition of a bulking elimination agent. Moreover, it can prevent that the cell body and cell residue of a fragmented filamentous bacterium mix in treated water, and the quality of treated water deteriorates. Furthermore, the phenomenon that the filamentous bacteria rise by containing bubbles in the voids between the mycelium of the generated filamentous bacteria can be eliminated in a short time because of the action of fragmenting the filamentous bacteria. Moreover, since it is a fundamental solution that kills filamentous bacteria, the effect lasts for a long time.

As described above, the bulking eliminating agent of the present invention contains a water-soluble cationic polymer having a specific monomer unit as an active ingredient. Such a bulking eliminating agent is unlikely to adversely affect the growth of useful microorganisms and protozoa in the activated sludge, and can provide treated water with good water quality.
Therefore, according to the present invention, it is possible to eliminate bulking by adapting to various causes while maintaining good water quality without adversely affecting the activated sludge. In particular, bulking caused by at least one filamentous bacterium in activated sludge can be more effectively eliminated.

  Moreover, according to this invention, the environmental pollution by the activated sludge flowing out can also be suppressed. Furthermore, the activated sludge expansion in the aeration tank can be eliminated, the activated sludge concentration can be kept high, and the BOD and / or COD removal effect can be significantly improved. Furthermore, since the sedimentation volume can be reduced, it is very easy to settle and separate activated sludge in a sedimentation tank, and it is not necessary to frequently remove excess activated sludge.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

[Evaluation]
<Measurement of SVI (sludge volume index)>
SVI is an index that represents the activated sludge sedimentation properties, and indicates the volume occupied by 1 g of activated sludge suspended solids when the activated sludge mixed liquid is allowed to stand for 30 minutes. SV30 (activated sludge sedimentation rate) and It calculated by following Formula from MLSS (activated sludge suspended solids), and made the case where SVI was 200 mL / g or less into a favorable state.
SVI [mL / g] = SV30 [%] × 10,000 / MLSS [mg / L]
In addition, SV30 is based on the ordinary method (Japan Sewerage Association, edited by the Sewerage Test Act, Vol. 1997 edition p271), while MLSS is the ordinary method (Japan Sewerage Association, edited by the Sewerage Test Act, Vol. 1997). Version "p269).

<Measurement of the growth number of filamentous bacteria>
The number of filamentous bacteria growing in the activated sludge mixed solution was counted with a phase contrast microscope (Raymer microscope, “BX-2700TPH”). The number of filamentous bacteria grown was determined based on the classification of the appearance state (edited by the Japan Sewerage Association, “Sewerage Test Method, Vol. 1997, p375”). Note that “1” was very small and “6” was very large, and the determination was made in six stages.

<Measurement of turbidity of supernatant>
The turbidity of the supernatant of the activated sludge mixture was measured with a turbidimeter (manufactured by ASONE Co., Ltd., “TN-100”).

<Determining the effect of protozoa on motility>
The presence or absence of an influence on the motility of the protozoa in the activated sludge mixed solution was visually determined with a phase contrast microscope. When the protozoan motility decreased compared to normal, it was judged to be affected.

[Production of bulking agent 1]
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 65 g of deionized water and 0.2 g of sodium hypophosphite were put, deaerated by circulating nitrogen, then heated to 70 ° C., 8 g of a 10% by mass aqueous solution of 2′-azobis (2-amidinopropane) hydrochloride was added, 100 g of an 80% by mass aqueous solution of N-vinylformamide was added dropwise over 2 hours, and 2,2′-azobis (2-amidinopropane) was further added. ) 4 g of a 10% by mass aqueous solution of hydrochloride was added and stirred at 70 ° C. for 2 hours. To the obtained polymer solution, 112 g of 35 mass% hydrochloric acid was added and stirred at 70 ° C. for 3 hours to obtain an aqueous solution of a water-soluble cationic polymer. This was designated as bulking canceling agent 1.

<Characteristics of bulking remover 1>
(composition)
A small amount of the aqueous solution (bulking-removing agent) of the water-soluble cationic polymer obtained earlier was taken, added to acetone, precipitated, and dried in vacuo to obtain a solid water-soluble cationic polymer. The water-soluble cationic polymer was dissolved in heavy water, and a ¹³ C-NMR spectrum was measured with an NMR spectrometer (manufactured by JEOL Ltd., 270 MHz). The composition of each monomer unit was calculated from the integrated value of the peak corresponding to each repeating unit in the ¹³ C-NMR spectrum.
As a result, the bulking canceling agent 1 contained a water-soluble cationic polymer in which the unit represented by the formula (1) was 95 mol% and the unit represented by the formula (2) was 5 mol%. .

(Reduced viscosity measurement)
A 0.1 g / dL solution was prepared by dissolving 0.1 g of a solid water-soluble cationic polymer obtained in the measurement of the composition in 100 mL of 1N saline. The reduced viscosity at 25 ° C. of the solution was measured with an Ostwald viscometer (Hario Laboratories).
As a result, the reduced viscosity was 0.3 dL / g.

[Test 1]
<Example 1>
1 L of activated sludge (MLSS: 5800 mg / L, SV30: 77%) from a wastewater treatment facility of a sugar factory where bulky bacteria (Thiotrix sp, Type 0961) are dominant and causing bulking is put into a beaker, and bulking agent 1 Was diluted 10 times with deionized water, added so that the amount of polymer added was 5% by mass with respect to the amount of activated sludge suspended solids, stirred for 2 hours, and then allowed to stand for 12 hours. The bulking elimination effect after leaving for 12 hours was judged. The results are shown in Table 1.

<Comparative Example 1>
The bulking elimination effect was determined in the same manner as in Example 1 except that the bulking elimination agent 1 was not added. The results are shown in Table 1.

[Test 2]
<Example 2>
Except for using 1L of activated sludge (MLSS: 8100mg / L, SV30: 100%) of the methylamine production wastewater treatment facility of a chemical factory where filamentous bacteria (Type021N, Nostocoida limicola, Type1701) are dominant and causing bulking In the same manner as in Example 1, the bulking elimination effect was determined. The results are shown in Table 2.

<Comparative Example 2>
The bulking elimination effect was determined in the same manner as in Example 2 except that the bulking elimination agent 1 was not added. The results are shown in Table 2.

[Test 3]
<Example 3>
Except for using 1 L of activated sludge (MLSS: 3800 mg / L, SV30: 92.8%) in a cornstarch wastewater treatment facility in which bulky bacteria (Type021N, Beggiatoa, Sphaerotilus natans, Type0041) are dominant and causing bulking In the same manner as in Example 1, the bulking elimination effect was determined. The results are shown in Table 3.

<Comparative Example 3>
The bulking elimination effect was determined in the same manner as in Example 3 except that the bulking elimination agent 1 was not added. The results are shown in Table 3.

[Test 4]
<Example 4>
Activated sludge (MLSS) of a facility that treats wastewater from the production of pharmaceutical intermediates in a chemical factory that has caused sedimentation failure due to the dismantling of sludge flocs (the presence of flocs with a diameter of 100 μm or less in a microscopic observation is 50% or more) 4670 mg / L, SV30: 96.5%) The bulking elimination effect was determined in the same manner as in Example 1 except that 1 L was used. The results are shown in Table 4.
In the activated sludge used in Test 4, type 1851, Gordona amarae, and Type0092 were dominant as filamentous bacteria.

<Comparative example 4>
The bulking elimination effect was determined in the same manner as in Example 4 except that the bulking elimination agent 1 was not added. The results are shown in Table 4.

[Test 5]
<Examples 5-1 to 5-6>
Activated sludge (MLSS) of a papermaking wastewater treatment facility in a paper mill that has caused sedimentation failure due to dispersion of sludge floc (in a state where the appearance of dispersed bacteria is 5.0 × 10 ⁵ cells / cm ² or more in microscopic observation) 7800 mg / L, SV30: 94%) 1 L was placed in a beaker, and a 1% by mass aqueous solution of polyaluminum chloride was added to a concentration shown in Table 5. Subsequently, the bulking remover 1 was added to a concentration shown in Table 5, stirred for 3 minutes, and then allowed to stand for 12 hours. The bulking elimination effect after leaving for 12 hours was judged. Table 5 shows the addition concentrations of the polyaluminum chloride aqueous solution and the bulking remover 1 and the results.

<Comparative Examples 5-1 and 5-2>
The bulking elimination effect was determined in the same manner as in Examples 5-1 to 5-6 except that the bulking elimination agent 1 was not added. The results are shown in Table 5.

[Production of bulking agent 2]
Into a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, cyclohexane is added as a dispersion medium, 0.5 mass% ethylcellulose is added thereto, and a 60 mass% N-vinylformamide aqueous solution is added to the dispersion medium. The mixture was added to a ratio of 1/2, deaerated by flowing nitrogen under stirring, then heated to 70 ° C., and 3000 ppm of 2,2′-azobis (2-amidinopropane) hydrochloride with N-vinylformamide was added. It added as 10 mass% aqueous solution, and superposed | polymerized by stirring for 2 hours as it was. Thereafter, the reaction solution was added to a large amount of acetone, and the precipitated polymer was taken out and dried.
In alkaline water obtained by dissolving 2.1 g of sodium hydroxide in deionized water and adding it to 94.8 g, 5.2 g of the removed polymer was added and dissolved while stirring, and the temperature was further raised to 80 ° C. for 3.5 hours. An aqueous solution of a water-soluble cationic polymer was obtained. This was designated as bulking canceling agent 2.

<Characteristics of bulking remover 2>
(composition)
The ¹³ C-NMR spectrum was measured in the same manner as the bulking canceling agent 1, and the composition of each monomer unit was calculated.
As a result, the bulking eliminating agent 2 contained a water-soluble cationic polymer in which the unit represented by the formula (1) was 62 mol% and the unit represented by the formula (2) was 38 mol%. .

(Reduced viscosity measurement)
The reduced viscosity was measured in the same manner as bulking canceling agent 1.
As a result, the reduced viscosity was 8.0 dL / g.

[Test 6]
<Example 6>
Activated sludge (MLSS: 11600 mg) in a wastewater treatment facility of a fish processing factory that has caused poor sedimentation due to dispersion of sludge floc (in a state where the appearance amount of dispersible bacteria is 5.0 × 10 ⁵ cells / cm ² or more in microscopic observation) / L, SV30: 98%) After putting 1 L into a beaker, diluting bulking agent 2 100 times with deionized water, adding 0.03% by mass to the amount of activated sludge mixture, and stirring for 3 minutes , Left for 12 hours. The bulking elimination effect after leaving for 12 hours was judged. The results are shown in Table 6.

<Comparative Example 6>
The bulking elimination effect was determined in the same manner as in Example 6 except that the bulking elimination agent 2 was not added. The results are shown in Table 6.

[Production of bulking agent 3]
Bulking remover 3 was obtained in the same manner as bulking remover 2, except that the amount of sodium hydroxide was 3.2 g.

<Characteristics of bulking agent 3>
(composition)
The ¹³ C-NMR spectrum was measured in the same manner as the bulking canceling agent 1, and the composition of each monomer unit was calculated.
As a result, the bulking eliminating agent 3 contained a water-soluble cationic polymer in which the unit represented by the formula (1) was 82 mol% and the unit represented by the formula (2) was 18 mol%. .

(Reduced viscosity measurement)
The reduced viscosity was measured in the same manner as bulking canceling agent 1.
As a result, the reduced viscosity was 5.4 dL / g.

[Test 7]
<Example 7>
Put 1L of activated sludge (MLSS: 7200mg / L, SV30: 96%) of the emulsion polymerization wastewater treatment facility of the resin factory of the chemical factory that is causing sedimentation failure due to increased viscosity of the activated sludge into the beaker, and remove the bulking agent 3 After diluting 100 times with ionic water, adding 0.02% by mass with respect to the amount of the activated sludge mixture, stirring for 3 minutes, and then leaving it for 12 hours. The bulking elimination effect after leaving for 12 hours was judged. The results are shown in Table 7.

<Comparative Example 7>
The bulking elimination effect was determined in the same manner as in Example 7 except that the bulking elimination agent 3 was not added. The results are shown in Table 7.

[Production of bulking agent 4]
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 133 g of water and 70 g of N-vinylformamide were added to dissolve N-vinylformamide. To this was added 0.9 g of 2,2′-azobis (2-amidinopropane) hydrochloride. The oxygen was then excluded by introducing nitrogen and the reaction mixture was warmed to 70 ° C. within 1 hour. Furthermore, it hold | maintained at 70 degreeC for 3 hours, and obtained the polymer solution.
To the obtained polymer solution, 502 g of a 10% by mass sodium hydroxide solution was mixed and heated to 80 ° C. for 5 hours to obtain an aqueous solution of a water-soluble cationic polymer. This aqueous solution was designated as bulking canceling agent 4.

<Characteristics of bulking agent 4>
(composition)
The ¹³ C-NMR spectrum was measured in the same manner as the bulking canceling agent 1, and the composition of each monomer unit was calculated.
As a result, the bulking canceling agent 4 contained a water-soluble cationic polymer in which the unit represented by the formula (1) was 95 mol% and the unit represented by the formula (2) was 5 mol%. .

(Reduced viscosity measurement)
The reduced viscosity was measured in the same manner as bulking canceling agent 1.
As a result, the reduced viscosity was 0.5 dL / g.

[Test 8]
<Example 8>
Activated sludge (MLSS: 6300 mg / L, SV30) of a papermaking wastewater treatment facility in a paper mill that has caused poor sedimentation due to the dismantling of sludge flocs (the state in which the presence of flocs having a diameter of 100 μm or less in a microscopic observation is 50% or more) 100%) 1 L was put into a beaker, the bulking agent 4 was diluted 100 times with deionized water, added 0.02% by mass with respect to the amount of the activated sludge mixture, stirred for 3 minutes, and then left for 12 hours. . The bulking elimination effect after leaving for 12 hours was judged. The results are shown in Table 8.

<Comparative Example 8>
The bulking elimination effect was determined in the same manner as in Example 8 except that the bulking elimination agent 4 was not added. The results are shown in Table 8.

As is clear from Tables 1 to 8, the sludge sedimentation was improved in each example. Moreover, when the state of the fungus body was observed with a phase-contrast microscope, the filamentous body of each filamentous bacterium was cut and fragmented, and the number of growth decreased compared to each comparative example (when no bulking-eliminating agent was added). . Furthermore, the turbidity of the supernatant decreased and no effect on the movement of protozoa was observed.
On the other hand, in each comparative example, filamentous bacteria were not fragmented, and the number of growth was larger than in the examples. Moreover, the turbidity of the supernatant was also higher than in the examples.

Claims (2)

A bulking eliminating agent comprising a water-soluble cationic polymer having monomer units represented by the following formulas (1) and (2) as an active ingredient.

  The water-soluble cationic polymer has 1 to 99.9 mol% of the monomer unit represented by the above formula (1) as a repeating unit, and the monomer unit represented by the above formula (2) as a repeating unit. And a reduced viscosity at 25 ° C. of 0.01 to 15 dL / g when made into a 0.1 g / dL solution with 1N saline. Item 4. A bulking-eliminating agent according to Item 1.