JP2011050946A - Method for removing coloring component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently removing a hardly-biodegradable water-soluble coloring component remaining in activated sludge by using a small amount of an organic polymer flocculant. <P>SOLUTION: The method for removing the coloring component in an activated sludge-mixed liquid includes the steps of: adding a coloring component removing agent, which contains at least one polymer of water-soluble and/or water-absorbing cationic polymers (a), (b) each containing a unit shown by the predetermined general formula and water-soluble and/or water-absorbing amphoteric polymers as an effective component, to the activated sludge-mixed liquid, which contains the hardly-biodegradable water-soluble coloring component and has ≥50 chromaticity, in the presence of ≥500 mg/L suspended solid content; and subjecting the coloring component removing agent-added activated sludge-mixed liquid to solid-liquid separation. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for removing hardly biodegradable water-soluble coloring components remaining in activated sludge of waste water.

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 the solid-liquid separation tank such as sludge sedimentation layer and floating layer is aerated. 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, organic matter is decomposed by flocs (activated sludge) in which various microorganisms gather, centering on bacteria such as zoom glare, but water-soluble coloring materials that are hardly biodegradable are added to organic wastewater. When it contains, a coloring component may remain in the supernatant liquid in a solid-liquid separation tank.
In the present invention, the hardly biodegradable water-soluble coloring component is an organic substance having an anionic or amphoteric functional group that is difficult to remove by ordinary activated sludge treatment, and is a humic substance, lignin degradation product, bilirubin-like Substances and other pollutants such as water-soluble colored polymer substances produced by aminocarbonyl reaction. BOD (biological oxygen demand) / CODMn (chemical oxygen demand by potassium permanganate) is 0.1 or less In addition, the carbon content is 10 mg / L aqueous solution having a chromaticity of 20 or more.
Non-biodegradable water-soluble coloring components such as humic substances are substances contained in waste water, groundwater, etc., as shown in Non-Patent Document 1 and Non-Patent Document 2, for example. It is dissolved in water and cannot be separated and removed by coagulation sedimentation. Moreover, since these coloring components are difficult to be decomposed by microorganisms, it is difficult to remove them by an activated sludge method, which is a general treatment method. Although adsorption treatment with activated carbon or the like is possible, the cost is extremely high.
Among the above-mentioned hardly biodegradable water-soluble coloring components, bilirubin-like substances refer to metabolites of blood pigments contained in human waste and livestock wastewater. In addition to bilirubin, a red-brown bile pigment, Including. Although bilirubin-like substances can be chemically treated, it is economically difficult to carry out currently known methods, so it is actually diluted and released, so a treatment method with low environmental impact is required. It has been.

The colored wastewater containing the hardly biodegradable water-soluble coloring component as described above may have a high COD even if the standard value such as BOD is achieved by the treatment by the activated sludge method. Moreover, these coloring components show coloring even if the content is small. Therefore, wastewater (treated water) after treating sewage, human waste, livestock wastewater, food production wastewater, papermaking wastewater, etc. with activated sludge contains such hardly biodegradable water-soluble coloring components. Therefore, discharging the wastewater while containing it leads to contamination of water resources, and if the colored wastewater is discharged, it causes complaints from the residents in the vicinity.
Furthermore, colored components such as humic substances contain precursors that become trihalomethanes harmful to the human body during chlorination treatment, and there is a concern that the quality of water intake will deteriorate if released into rivers. Yes.
In addition, it is known that the above-mentioned coloring component causes fouling even in a filtration process using a filtration membrane or the like and causes a reduction in filtration performance.

In recent years, when environmental pollution has been severely questioned, the effluent regulations regarding such effluent treatment have been further strengthened, so the need for more advanced effluent treatment has increased, and the development of a low-cost and efficient water treatment method is desired. Yes.
Accordingly, various treatment methods for waste water containing the above-described coloring components have been proposed. For example, a waste water treatment method having an ozone treatment step and an accelerated oxidation treatment step using a combination of ozone addition and ultraviolet irradiation (for example, patent literature) 1, Non-Patent Document 3), a method of removing by contacting with an ion exchange resin (for example, Patent Document 2), a method of adding and removing a porous material supporting titanium (for example, Patent Document 3), activated sludge Examples include a method of adding an inorganic flocculant and an organic polymer flocculant to treated water (for example, Patent Document 4 and Patent Document 5). However, these methods are not yet satisfactory from the viewpoints of process complexity, removal efficiency, and economical efficiency.
Note that Patent Document 6 discloses that polyvinylamine, which is one of the cationic polymers, can be used for decolorization of dye wastewater.

JP 2006-224065 A JP 2000-254488 A JP 2005-238174 A JP 2003-181491 A JP-A-6-226265 Japanese Patent Laid-Open No. 8-81519

Masato Ueda, Yoshiaki Sakamoto: Collection and characterization of groundwater humic substances using rigid adsorbent resin, nuclear backend research, vol. 12 No. 1-2 (2006) Yusaku Nogami, Tomoko Minami Arita, Masamitsu Miyanaga: Effect of fulvic acid on the COD of activated sludge treated water from domestic wastewater, water and wastewater vol. 43 No. 12 (2001) Tatsuma Mori, Michio Sakimoto: New decolorization technology, research on livestock, Vol. 57, No. 1 (2003)

As described above, the known method is not a satisfactory method for removing the hardly biodegradable water-soluble coloring component in the waste water. For example, the method of treating with ozone described in Patent Document 1 is not only high in cost but also requires adjustment of reaction conditions, so that the types of applicable wastewater are limited. Further, in the methods described in Patent Documents 2 and 3, in which the coloring component is adsorbed and removed to the solid content, since the adsorption capacity is limited, frequent cleaning and replacement of the filter medium are required. Furthermore, as described in Patent Documents 4 and 5, the method of adding an inorganic flocculant and an organic polymer flocculant requires not only a large amount of flocculant but also a large amount for adjusting pH. There was a problem that alkali was required and a large amount of sludge was generated after the treatment. About patent document 6, the object is restricted to dyeing | draining waste_water | drain, It was not known that the coloring component of other waste_water | drain can be removed.
In the process of removing the hardly biodegradable water-soluble coloring component remaining in the activated sludge, the present invention uses a small amount of a polymer flocculant as compared with the conventional method, and is inexpensive, simple and less sludge. An object of the present invention is to provide a method capable of removing the coloring component by the generation amount and reducing the concentration thereof.

  The present invention relates to a method for efficiently removing water-soluble hardly biodegradable coloring components remaining in activated sludge, the gist of which is the amidine structural unit represented by the following general formula (1) and / or the following general A water-soluble and / or water-absorbing cationic polymer (a) containing an amidine structural unit represented by the formula (2), a water-soluble and / or water-polymerized polymer obtained by polymerizing a monomer represented by the following general formula (3) Alternatively, a coloring component remover containing at least any one of a water-absorbing cationic polymer (b) and a water-soluble and / or water-absorbing amphoteric polymer as an active ingredient is a floating solid content of 500 mg / L or more. A method for removing colored components in an activated sludge mixed solution, comprising adding to an activated sludge mixed solution having a chromaticity of 50 or more containing a hardly biodegradable water-soluble colored component in the presence, followed by solid-liquid separation. Exist.

  As a more preferred method of the method of the present invention, in the activated sludge mixed liquid, the main component of the coloring component is not a dye; the hardly biodegradable water-soluble coloring component is a humic substance and a lignin decomposition product. A bilirubin-like substance and at least one water-soluble colored polymer substance produced by an aminocarbonyl reaction; 0.1 to 2000 mg / L of the coloring component remover added to the activated sludge mixed solution Is mentioned.

  As still another preferred embodiment, the amphoteric polymer is an amphoteric polymer containing a monomer unit represented by the following general formula (4) and a monomer unit represented by the following general formula (5); The cationic polymer (a) contains 5 to 90 mol% of an amidine structural unit represented by the following general formula (1) and / or an amidine structural unit represented by the following general formula (2); The polymer (b) contains 10 to 100 mol% of a unit derived from a monomer represented by the following general formula (3); the amphoteric polymer is a single unit represented by the following general formula (4). It is mentioned that it is an amphoteric polymer containing 10 to 98 mol% of a monomer unit and 2 to 30 mol% of a monomer unit represented by the following general formula (5).

  According to the method of the present invention, at least any one of the water-soluble and / or water-absorbing cationic polymers (a) and (b) and the amphoteric polymers, which are organic polymer flocculants in a small amount used compared with the conventional method. Therefore, the concentration of the hardly biodegradable water-soluble coloring component remaining in the activated sludge can be reduced at a low cost and with a small sludge generation amount. In addition, according to the present invention, since the organic polymer flocculant only needs to be added to the activated sludge, the colored components can be easily removed without increasing the number of treatment steps.

The method of the present invention relates to a method for removing a hardly biodegradable water-soluble coloring component in an activated sludge mixed liquid with a coloring component removing agent, and the coloring component removing agent is a so-called polymer flocculant, which is water-soluble and / or The main component is at least one of a water-absorbing cationic polymer and / or an amphoteric polymer.
The water-soluble and / or water-absorbing cationic polymer used as a component of the color removal agent of the present invention is an amidine structural unit represented by the following general formula (1) and / or an amidine represented by the following general formula (2). It is at least one selected from a cationic polymer (a) containing a structural unit and a cationic polymer (b) obtained by polymerizing a monomer represented by the following general formula (3). The polymer may be a crosslinkable gel.

[In the formulas (1) and (2), R ^{1 to} R ² are each a hydrogen atom or a methyl group, and may be the same or different. X < ^- > each represents an anion, and may be the same or different. ]

[In Formula (3), Z < ^- > represents an anion. ]

The water-soluble and / or water-absorbing cationic polymer (a) used in the present invention has an amidine structure unit represented by the above general formula (1) and / or an amidine structure represented by the following general formula (2). It has a unit. Specific examples of the anion represented by X ⁻ in the general formulas (1) and (2) include Cl ⁻ , Br ⁻ , 1 / 2SO ₄ ²⁻ , CH ₃ (CO) O ⁻ , H ( CO) O- ^{and the} like. Of these, Cl ^- is preferable.
The method for producing such a cationic polymer (a) is not particularly limited. For example, an ethylenically unsaturated monomer having a primary amino group or a substituted amino group capable of generating a primary amino group by a conversion reaction, and acrylonitrile. Alternatively, a method may be mentioned in which a copolymer of methacrylonitrile with nitriles is produced, and after acid hydrolysis, a cyano group and a primary amino group in the copolymer are reacted to form an amidine.

Examples of the ethylenically unsaturated monomer of the general formula _CH 2 ⁼ CR a -NHCOR ^b (wherein, ^{R a} represents hydrogen atom or a methyl group, a ^{R b} is an alkyl group or a hydrogen atom having 1 to 4 carbon atoms The compound represented by this is preferable. In the copolymer with nitriles, the substituted amino group derived from such a compound is easily converted to a primary amino group by hydrolysis or alcoholysis. Furthermore, this primary amino group reacts with an adjacent cyano group to be amidined. Examples of the compound include N-vinylformamide (R ^a = H, R ^b = H), N-vinylacetamide (R ^a = H, R ^b = CH ₃ ) and the like.
The polymerization molar ratio of these ethylenically unsaturated monomers and nitriles is usually 20:80 to 80:20, but if desired, the polymerization molar ratio outside this range, for example, the ratio of ethylenically unsaturated monomers. It is also possible to employ a large polymerization molar ratio. In general, when the ratio of amidine structural units in the water-soluble and / or water-absorbing cationic polymer is larger, the performance when used as a coloring component remover is superior. Moreover, it is thought that the vinylamine structural unit also contributes advantageously to the performance as a coloring component remover. Accordingly, the polymerization molar ratio of the ethylenically unsaturated monomer and the nitrile that gives a copolymer suitable as a coloring component remover is generally 20:80 to 80:20, particularly preferably 40:60 to 60: 40.

As a method for copolymerizing the ethylenically unsaturated monomer and the nitrile, an ordinary radical polymerization method is used, and any of bulk polymerization, aqueous solution precipitation 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. Although a general radical polymerization initiator can be used as the polymerization initiator, 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 copolymer can be used as it is or diluted to be subjected to an amidation reaction. Alternatively, the solvent can be removed by a known method and dried to separate the copolymer as a solid, and then dissolved again to be subjected to an amidation reaction.
In the amidation reaction, when the N-vinylamide compound represented by the above general formula is used as the ethylenically unsaturated monomer, the substituted amino group of the copolymer is converted into a primary amino group, and then the generated primary amino group The water-soluble and / or water-absorptive cationic polymer (a) used in the present invention can be produced by carrying out a two-step reaction in which an amidine structure is formed by reacting with an adjacent cyano group.
Note that the copolymer may be heated in water in the presence of a strong acid to produce an amidine structure in one step. Even in this case, it is considered that a primary amino group is first generated as an intermediate structure.

  Specific conditions for the amidation reaction include, for example, 0.1 to 5.0 times, preferably 0.5 to 3.0 times equivalent of strong acid, preferably hydrochloric acid, with respect to the substituted amino group in the copolymer. And a cationic polymer having an amidine structural unit can be obtained by heating at a temperature of usually 80 to 150 ° C., preferably 90 to 120 ° C., usually for 0.5 to 20 hours. In general, the larger the equivalent ratio of strong acid to substituted amino group and the higher the reaction temperature, the more the amidation proceeds. In addition, it is preferable that 10% by mass or more, preferably 20% by mass or more of water is usually present in the reaction system with respect to the copolymer to be subjected to the reaction in the amidine formation.

The water-soluble and / or water-absorbing cationic polymer (a) used in the present invention is most typically prepared by copolymerizing N-vinylformamide and acrylonitrile according to the above description. It is preferred that the polymer is usually produced as a water suspension in the presence of hydrochloric acid to form amidine structural units from cyano groups adjacent to the substituted amino groups. And the water-soluble and / or water-absorbing cationic polymer (a) of various compositions is selected by selecting the molar ratio of N-vinylformamide and acrylonitrile to be subjected to copolymerization, and the amidation conditions of the copolymer. Is obtained.
The water-soluble and / or water-absorptive cationic polymer (a) thus obtained is the amidine structural unit represented by the above general formula (1) and / or the above general one in 100 mol% of the cationic polymer. It is preferable to contain 5 to 90 mol% of the amidine structural unit represented by the formula (2) as a repeating unit. When the content of these amidine structural units is less than 5 mol%, the content of the amidine structural units is too small, so that the amount used is increased when the coloring component remover is used. On the other hand, it is difficult to produce those in which the content of the amidine structural unit exceeds 90 mol% by the method described above. The lower limit of the content of the amidine structural unit is more preferably 10 mol% or more, further preferably 15 mol% or more, and particularly preferably 20 mol% or more. Further, the upper limit of the content of the amidine structural unit is more preferably 85 mol% or less, and further preferably 80 mol% or less.

  When the cationic polymer (a) is produced by the above-described method, it contains at least one selected from units represented by any one of the following general formulas (6) to (8) in addition to the amidine structural unit. There is a case.

In general formulas (6) to (8), R ¹¹ , R ¹³ , and R ¹⁴ are each a hydrogen atom or a methyl group, and may be the same or different.
R ¹² is an alkyl group having 1 to 4 carbon atoms or a hydrogen atom.
Q ⁻ is an anion. The anion is the same as the anion exemplified above in the description of the general formulas (1) and (2).

When the cationic polymer (a) in the present invention contains a unit represented by any one of the above general formulas (6) to (8), usually, the cationic polymer (a) in 100 mol%, the above The repeating unit represented by the general formula (6) is 0 to 40 mol%, the repeating unit represented by the general formula (7) is 0 to 70 mol%, and the repeating unit represented by the general formula (8) is Contains 0 to 70 mol%.
The composition of the amidine structural unit represented by the general formula (1), the amidine structural unit represented by the general formula (2), and the unit represented by any one of the general formulas (6) to (8) is as follows: It can be adjusted by the polymerization molar ratio between the ethylenically unsaturated monomer and the nitrile and the conditions (temperature and time) of the amidine reaction.
Further, these compositions can be obtained by measuring ¹³ C-NMR ( ¹³ C-nuclear magnetic resonance) of the cationic polymer. Specifically, the ¹³ C-NMR spectrum corresponding to each repeating unit is obtained. It can be calculated from the integrated value of the peak (signal).

The cationic polymer (b) used in the present invention is a cationic polymer obtained by polymerizing the monomer represented by the general formula (3) and includes units derived from the monomer.
The cationic polymer (b) preferably contains 10 to 100 mol% of units derived from the monomer represented by the general formula (3).
In the general formula (3), the anion represented by Z- specifically represents a halogen ion such as F-, Cl-, Br- or the like.
Specifically, the cationic polymer (b) is preferably a homopolymer of a diallylamine-based cationic monomer as shown below.

  Examples of diallylamine cationic monomers used in the present invention include inorganic salts of secondary amines such as diallylamine and dimethallylamine or organic acid salts, inorganic salts of tertiary amines such as diallylmethylamine, diallylethylamine and diallylbutylamine, or Examples include organic acid salts, quaternary ammonium salts such as diallyldimethylammonium chloride, diallyldimethylammonium bromide, diallyldiethylammonium chloride, diallyldiethylammonium bromide, diallyldibutylammonium chloride, diallyldibutylammonium bromide. Among these, diallyldimethylammonium chloride is particularly preferable.

Next, the water-soluble and / or water-absorbing amphoteric polymer used in the present invention will be described.
The amphoteric polymer is preferably a vinyl amphoteric polymer having a monomer unit represented by the following general formula (4) and a monomer unit represented by the following general formula (5).

[In Formula (4), R ³ represents a hydrogen atom or a methyl group, R ⁴ represents an alkylene group having 1 to 4 carbon atoms, R ⁵ represents an alkyl group having 1 to 4 carbon atoms, and R ⁶ represents a hydrogen atom. represents an alkyl group or a benzyl group having 1 to 4 carbon atoms, a represents -O- or -NH-, Y ^- represents an anion. ]

Wherein ^{(5), R 7, R} 8 represents a hydrogen atom, a methyl group or a -COO ^- represents M '(. Representing a ⁺ M' ⁺ is a hydrogen ion or other cation), B represents a single bond, alkylene group, a phenylene group having 1 to 2 carbon atoms, -COOR ⁹ - ^{(R 9} represents an alkylene group having 2 to 6 carbon atoms) or ^{-CONHR 10} - ^(R 10 represents an alkylene group having 2 to 6 carbon atoms ), W ⁻ represents —COO ^— or —SO ₃ ^— , and M ⁺ represents a hydrogen ion or other cation. ]

Examples of the vinyl cationic monomer used as a raw material for the monomer unit represented by the general formula (4) include dimethylamino (methyl, ethyl, propyl, or butyl) acrylate or methacrylate, diethylamino (methyl, ethyl, propyl, or Butyl) acrylate or methacrylate, di-n-propylamino (methyl, ethyl, propyl or butyl) acrylate or methacrylate, diisopropylamino (methyl, ethyl, propyl or butyl) acrylate or methacrylate, di-n-butylamino (methyl, ethyl Propyl or butyl) acrylate or methacrylate, di-sec-butylamino (methyl, ethyl, propyl or butyl) acrylate or methacrylate, diisobutylamino (methyl, ethyl, pro Dialkylaminoalkyl esters of (meth) acrylic acid such as acrylate or methacrylate; dimethylamino (methyl, ethyl, propyl or butyl) acrylamide or methacrylamide, diethylamino (methyl, ethyl, propyl or butyl) acrylamide or methacryl Amide, di-n-propylamino (methyl, ethyl, propyl or butyl) acrylamide or methacrylamide, diisopropylamino (methyl, ethyl, propyl or butyl) acrylamide or methacrylamide, di-n-butylamino (methyl, ethyl, propyl) Or butyl) acrylamide or mecrylamide, di-sec-butylamino (methyl, ethyl, propyl or butyl) acrylamide or mecrylamide, di Neutralized salts of dialkylaminoalkyl (meth) acrylamides such as sobutylamino (methyl, ethyl, propyl or butyl) acrylamide or methacrylamide with hydrogen halide, sulfuric acid, nitric acid, organic acid, alkyl halide, pendyl halide, dimethyl Quaternized compounds such as sulfuric acid and diethyl sulfuric acid are listed. These vinyl monomers may be used alone or in combination of two or more.
The anion represented by Y ⁻ in the general formula (4) specifically represents Cl ⁻ , Br ⁻ , 1 / 2SO ₄ ²⁻ .

Examples of the vinyl anionic monomer used as a raw material for the monomer unit represented by the general formula (5) include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, vinyl sulfonic acid, and allyl sulfonic acid. , Methallylsulfonic acid, styrenesulfonic acid, 2-acrylamidoethanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-methacrylamideamidoethanesulfonic acid, 2-methacrylamide-2-methylpropanesulfonic acid, 2- Acryloyloxyethanesulfonic acid, 3-acryloyloxypropanesulfonic acid, 4-acryloyloxybutanesulfonic acid, 2-methacryloyloxyethanesulfonic acid, 3-methacryloyloxypropanesulfonic acid, 4-methacryloyloxybutanesulfonic acid, and these Alkali metal, metal salt or an ammonium salt such as alkaline earth metals are exemplified. These anionic monomers may be used alone or in combination of two or more.
In the general formula (5), M ′ ⁺ and M ⁺ each independently represent a hydrogen ion or other cation. Specific examples of the other cation include alkali metal ions such as Na ⁺ and K ⁺ , alkaline earth metal ions, and ammonium ions.

  Further, the amphoteric polymer may contain a monomer unit derived from a nonionic monomer. Examples of the nonionic monomer include (meth) acrylamide, (meth) acrylic acid ester, (meta ) Other copolymerizable nonionic vinyl monomers such as acrylonitrile and vinyl acetate. Of the nonionic monomers, acrylamide is particularly preferred. The monomer unit derived from such a nonionic monomer is usually contained in an amount of 0 to 90 mol%, preferably 0 to 80 mol%.

There is no restriction | limiting in particular about the manufacturing method of said water-soluble and / or water-absorbing amphoteric polymer, Well-known manufacturing methods, such as aqueous solution polymerization, dispersion polymerization, and emulsion polymerization polymer modification | denaturation, are used. About the ratio of each component in an amphoteric polymer, the monomer unit shown by General formula (4) is 10-98 mol%, Preferably it is 15-95 mol%, The single quantity shown by General formula (5) It is preferable that the body unit contains 2 to 30 mol%, preferably 5 to 25 mol%. Outside this range, the effect as a coloring component remover is not sufficient, which is not preferable.
In addition, as a method for producing a water-absorbing polymer (cationic polymer and amphoteric polymer), a polyfunctional crosslinking agent such as glyoxal or diepoxy compound is added to a raw material monomer mixture such as a cationic monomer. A method of polymerizing by adding water, a method of reacting a water-soluble polymer with a polyfunctional substance that reacts with the polymer and then crosslinking, a method of crosslinking the water-soluble polymer by heating, and the like are exemplified.

The coloring component remover in the present invention contains an active ingredient in an amount of at least one of a water-soluble and / or water-absorbing cationic polymer (a), (b) and an amphoteric polymer as a main component. However, it may contain other components. Examples of other components include formic acid and ammonium chloride.
In the present invention, the “effective component amount” means the total content of the water-soluble and / or water-absorbing cationic polymers (a) and (b) and the amphoteric polymer in 100% by mass of the coloring component remover. In general, it is preferably contained in an amount of 10 to 100% by mass.
When the coloring component remover contains other components, other components may be added so that the desired blending amount is obtained after the cationic polymer (a), (b) or the amphoteric polymer is produced. These (co) polymer production raw materials may be mixed with other components in advance.

The cationic polymer (a) containing the amidine structural unit represented by the general formula (1) and / or the amidine structural unit represented by the general formula (2), which is a main component of the coloring component removing agent of the present invention, and The cationic polymer (b) obtained by polymerizing the monomer represented by the general formula (3) and the amphoteric polymer are both in a 0.1 g / dL solution with 1 N saline. The reduced viscosity at 25 ° C. is preferably 0.01 to 10 dL / g, more preferably 0.1 to 8 dL / g. When the reduced viscosity is less than 0.01 dL / g, it tends to be difficult to produce the coloring component remover, or the function of the coloring component remover tends to deteriorate. On the other hand, when the reduced viscosity exceeds 10 dL / g, the viscosity of the aqueous solution of the coloring component remover becomes too high, which may cause inconvenience in addition.
The reduced viscosity described above can be controlled by adjusting the molecular weight, the ionic ratio, the molecular weight distribution, the production method, the composition distribution, and the like of the coloring component remover. For example, when the molecular weight of the coloring component remover is increased, the reduced viscosity tends to increase.

In the method of the present invention, the coloring component removing agent as described above is added to an activated sludge mixed liquid having a chromaticity of 50 or more, which has a suspended solid content of 500 mg / L or more and contains a hardly biodegradable water-soluble coloring component. Then, the water-soluble coloring component remaining in the activated sludge is removed by solid-liquid separation.
In the method of the present invention, the water-soluble coloring component is agglomerated together with the floating solid by adding a coloring component remover in a state where a certain amount of floating solid is present in the activated sludge mixed liquid, that is, in the presence of 500 mg / L or more. And can be removed as an aggregated precipitate.
Patent Document 6 describes that polyvinylamine can be used for the activated sludge mixed liquid to which a coloring component remover is added in the method of the present invention, in which the main component of the hardly decomposable water-soluble coloring component is a dye. In the present invention, other components are preferable.
The activated sludge mixed liquid preferably contains humic substances, lignin degradation products, bilirubin-like substances, and water-soluble colored polymer substances produced by aminocarbonyl reaction as hardly biodegradable water-soluble coloring components. . There is a possibility that the coloring component removing agent does not work sufficiently with other components.
Here, “water-soluble” means that 0.1 mg / L or more dissolves in water at 20 ° C.
The addition of the coloring component remover may be added to the activated sludge, or may be added to the solid-liquid separation tank or the concentrated sludge after the activated sludge treatment. If added to the concentrated sludge, the colored components in the dehydrated filtrate are removed, so the load on the activated sludge after return can be reduced.
The coloring component remover of the present invention may be used in combination with other decoloring agents, inorganic flocculants, and polymer flocculants as long as the effect is not impaired.

  In the present invention, “added to the activated sludge mixed solution” 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. In addition to direct addition to the aeration tank, direct addition to the aeration tank, direct addition to the oxygen-free tank at facilities with an oxygen-free tank for the purpose of denitrification, etc., as well as the removal effect of hardly biodegradable water-soluble coloring components As long as there is, any addition method may be used. 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.

(Addition to activated sludge)
In the method of the present invention, when the color component remover is added to the activated sludge in advance, the amount of the color component remover added is preferably 0.1 to 2000 mg / L, preferably 0.1 to 1000 mg / L with respect to the activated sludge mixed solution. Is more preferable. When the addition amount is less than 0.1 mg / L, the effect of the color component removing agent is not sufficiently obtained. On the other hand, when the addition amount exceeds 2000 mg / L, there is a possibility of adversely affecting the microbial activity in the activated sludge.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist.
In the following test examples (Examples and Comparative Examples), the coloring component remover was evaluated by measuring the chromaticity of the activated sludge supernatant.
<Measurement of chromaticity>
Chromaticity indicates the degree of pale yellow to yellowish brown due to a substance dissolved in water or present in a colloidal form, and is measured at around 390 nm by an ultraviolet-visible spectrophotometer (UV-3100 manufactured by Shimadzu Science Co., Ltd.). Absorbance was measured and calculated from a calibration curve using a standard solution.
The chromaticity was measured according to a conventional method (edited by the Japan Sewerage Association, “Sewerage Test Method, Vol. 1997, p95” “2. Transmitted light measurement method”).
The determination of the color component removal effect was performed by calculating the color component removal rate according to the following equation.
Removal rate (%) = (1−D ₂ / D ₁ ) × 100
(D ₁ : Chromaticity of colored wastewater to be treated, D ₂ : Chromaticity after removal of colored components)
<Measurement of pH>
The pH was measured using the method described in JIS K0102, adjusting the sample temperature to 23 ° C.

  The cationic polymer and the amphoteric polymer used in the test examples are collectively shown in Table 1.

[Cationic polymer (a)]
As the cationic polymer (a) used for the coloring component removing agent of the present invention, cationic polymers (A1, A2, A3) produced by the following method were used.
<Production of cationic polymer A1>
A mixture of 6 g of a mixture of acrylonitrile and N-vinylformamide (molar ratio 55:45) and 34 g of demineralized water was placed in a 50 ml four-necked flask equipped with a stirrer, a nitrogen inlet tube, and a condenser tube. The temperature was raised to 60 ° C. while stirring in nitrogen gas, and 0.12 g of a 10% by mass 2,2′-azobis (2-amidinopropane) dihydrochloride aqueous solution was added, and the mixture was further maintained for 3 hours. A suspension in which the coalescence precipitated was obtained. 20 g of water was added to the suspension, and 2 equivalents of concentrated hydrochloric acid was added to the formyl group of the polymer, and kept at 100 ° C. for 4 hours to obtain a yellow high-viscosity liquid. This was added to a large amount of acetone to precipitate a polymer, and the obtained polymer was chopped, dried at 60 ° C. for 1 night and pulverized to obtain a powdered water-soluble cationic polymer.

(Composition of cationic polymer A1)
The water-soluble cationic polymer A1 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 unit was calculated from the integrated value of the peak corresponding to each repeating unit of the ¹³ C-NMR spectrum. The structural units of the general formulas (1) and (2) were determined as the total amount without distinction. The results are shown in Table 1.
Moreover, each unit contained in the cationic polymer A1 obtained in this way is represented by R ^{1 to} R ² in the general formula [(1), (2), (6) to (8)], and R ^{11 to} R ¹⁴ were hydrogen atoms, and X ⁻ and Q ⁻ were chloride ions.
(Measurement of reduced viscosity of cationic polymer A1)
0.1 g of the cationic polymer A1 was dissolved in 100 mL of 1N saline to prepare a 0.1 g / dL solution. The reduced viscosity at 25 ° C. of the solution was measured with an Ostwald viscometer (Hario Laboratories). The results are shown in Table 1.

<Production of cationic polymer A2>
In a 500 ml four-necked flask equipped with a stirrer, a nitrogen introduction tube, and a cooling tube, 40 g of demineralized water, 1.2 g of polyethylene glycol 20000, and 0.2 g of sodium hypophosphite are added, and the temperature is raised to 70 ° C. Under a nitrogen stream, 120 g of a 70% by mass aqueous solution of a mixture of acrylonitrile and N-vinylformamide (molar ratio 50:50) was added dropwise over 2 hours. Meanwhile, 12.6 g of a 2% aqueous solution of 2,2′-azobis (2-amidinopropane) dihydrochloride in 10% by mass was added in 5 divided portions. After further aging for 2 hours, concentrated hydrochloric acid (corresponding to 100 mol% of formyl group) was added, the temperature was raised to 90 ° C., and the mixture was allowed to stand for 3 hours. This was added to a large amount of acetone to precipitate a polymer, and the resulting polymer was chopped, dried at 60 ° C. for 1 night and pulverized to obtain a cationic polymer.

(Composition of cationic polymer A2)
The ¹³ C-NMR spectrum was measured in the same manner as the cationic polymer A1, and the composition of each unit was calculated. Further, the structural units of the above general formulas (1) and (2) were determined as the total amount without distinction. The results are shown in Table 1.
In addition, each unit contained in the cationic polymer A2 thus obtained is represented by R ^{1 to} R ² in the general formula [(1), (2), (6) to (8)], and R ^{11 to} R ¹⁴ were hydrogen atoms, and X ⁻ and Q ⁻ were chloride ions.
(Reduced viscosity of the cationic polymer A2)
The reduced viscosity was measured in the same manner as the cationic polymer A1. The results are shown in Table 1.

<Production of cationic polymer A3>
A polymer obtained by crosslinking the cationic polymer A1 by a heat treatment (120 ° C., 5 hours), and its reduced viscosity was measured in the same manner as the cationic polymer A1. The results are shown in Table 1.

[Cationic polymer (b) and amphoteric polymer]
The cationic polymer (B1) produced by the following method was used as the cationic polymer (b) of the present invention, and amphoteric flocculants (C1 to C3) were selected from the commercially available grades as amphoteric polymers. . About the composition of each polymer, each polymer was dissolved in heavy water, and the ¹³ C-NMR spectrum was measured with an NMR spectrometer (manufactured by JEOL Ltd., 270 MHz). The composition of each unit was calculated from the integrated value of the peak corresponding to each repeating unit of the ¹³ C-NMR spectrum.
The reduced viscosity of each polymer was measured in the same manner as the cationic polymer A1.
The composition and reduced viscosity of the polymer are shown in Table 1.

<Production of cationic polymer B1>
32.3 g (0.2 mol) of diallyldimethylammonium chloride and 64.7 g of deionized water were placed in a 300 mL separable flask and dissolved uniformly. While stirring this aqueous solution, a solution of 20.3 mg (0.03 mmol) of 2,2,6,6-tetramethyl-1-piperidinyloxy radical (TEMPO) dissolved in 1.0 mL of methanol was added. TEMPO was dispersed in an aqueous solution. Next, nitrogen gas was bubbled in an ice bath at 500 mL / min for 3 hours to remove dissolved oxygen gas in the aqueous solution containing the monomer mixture. While stirring this aqueous solution, a solution of 22.8 mg (0.1 mmol) of ammonium peroxodisulfate dissolved in 1.0 mL of deionized water was added, and 19.0 mg (0.1 mmol) of sodium disulfite was further deionized. A solution dissolved in 1.0 mL of water was added. Three hours after the addition of the redox initiator, the aqueous solution was heated at 60 ° C. for 24 hours for polymerization to obtain a gel polymer. The intrinsic viscosity of this polymer was 1.6 dL / g.

(Composition of cationic polymer B1)
The ¹³ C-NMR spectrum was measured in the same manner as the cationic polymer A1, and the composition of each unit was calculated. The results are shown in Table 1.
(Reduced viscosity of the cationic polymer B1)
The reduced viscosity was measured in the same manner as the cationic polymer A1. The results are shown in Table 1.
In addition, as a comparative example, commercially available polymer flocculants: Diafloc K-415 (manufactured by Daianitrix Co., Ltd., containing 41 wt% of acrylic cationic polymer), Diafloc KP-201G (manufactured by Daianitrix Co., Ltd., dimethylaminoethyl methacrylate) Quaternary salt polymer) was used.

AAm: acrylamide unit DMC: methacryloyloxyethyltrimethylammonium chloride unit DADMAC: diallyldimethylammonium chloride unit DMQ: acryloyloxyethyltrimethylammonium chloride unit amidine: amidine hydrochloride unit NVF: N-vinylformamide unit AN: acrylonitrile unit VAM: vinylamine hydrochloride Salt unit AA: Acrylic acid unit

[Test 1]
<Example 1>
200 ml of colored sludge activated sludge (pH 6.2, chromaticity 314) is put in a beaker, and a predetermined amount of a coloring component remover shown in Table 2 is added in the form of a 0.1% by mass aqueous solution, followed by stirring for 2 minutes. Mix and let stand overnight. Thereafter, the absorbance at a wavelength of 390 nm was measured for the supernatant, and the chromaticity of the supernatant was calculated from the measured value to determine the effect of removing the colored components. The results are shown in Table 2.

<Comparative Example 1>
The effect of removing the coloring component was determined in the same manner as in Example 1 except that the coloring component removing agent was not added. The results are shown in Table 2.
<Comparative Example 2>
The colored component removal effect was determined in the same manner as in Example 1 except that a commercially available polyaluminum chloride flocculant (manufactured by Takasugi Pharmaceutical Co., Ltd., containing 10 to 11% of PAC: Al ₂ O ₃ component) was used. The results are shown in Table 2.
<Comparative Example 3>
The effect of removing the colored components was determined in the same manner as in Example 1 except that a commercially available polymer flocculant (Dianitricks Co., Ltd., Diafloc K-415) was used. The results are shown in Table 2.

[Test 2]
<Example 2>
The removal effect was determined using the coloring component remover shown in Table 3 in the same manner as in Example 1 except that 200 ml of colored sludge treatment site activated sludge (pH 6.7, chromaticity 175) was used. Furthermore, the pH of the activated sludge was adjusted to pH 5.5 using 0.1 N hydrochloric acid, and the coloring component removal effect was determined in the same manner as in Example 1. The results are shown in Table 3.
The solid sludge concentration of the activated sludge was 2,400 mg / L.
<Comparative example 4>
The effect of removing the coloring component was determined in the same manner as in Example 2 except that the coloring component removing agent was not added. The results are shown in Table 3.

[Test 3]
<Example 3>
Except for using 200 ml of activated sludge (pH 6.8, chromaticity 84) from a wastewater treatment plant of a colored paper mill, the removal effect was determined using the coloring component remover shown in Table 4 below. did. The results are shown in Table 4.
The solid sludge concentration of the activated sludge was 6,100 mg / L.
<Comparative Example 5>
The coloring component removal effect was determined in the same manner as in Example 3 except that the coloring component removing agent was not added. The results are shown in Table 4.
<Comparative Example 6>
The colored component removal effect was determined in the same manner as in Example 3 except that a commercially available polyaluminum chloride flocculant (manufactured by Takasugi Pharmaceutical Co., Ltd., containing PAC: Al ₂ O ₃ component was contained in an amount of 10 to 11%) was used. The results are shown in Table-4.
<Comparative Example 7>
The color component removal effect was determined in the same manner as in Example 1 except that a commercially available polymer flocculant (Dianitricks Co., Ltd., Diaflock KP-201G) was used. The results are shown in Table 4.

Claims (8)

A water-soluble and / or water-absorbing cationic polymer (a) containing an amidine structural unit represented by the following general formula (1) and / or an amidine structural unit represented by the following general formula (2), 3) a water-soluble and / or water-absorbing cationic polymer (b) obtained by polymerizing the monomer represented by 3) and at least one polymer selected from the group consisting of a water-soluble and / or water-absorbing amphoteric polymer. A coloring component removing agent as an active ingredient is added to an activated sludge mixed liquid having a chromaticity of 50 or more containing a water-soluble coloring component that is hardly biodegradable in the presence of 500 mg / L or more of floating solids, and then solid-liquid separation. A method for removing a coloring component in an activated sludge mixed liquid characterized by comprising:
[In the formulas (1) and (2), R ^{1 to} R ² are each a hydrogen atom or a methyl group, and may be the same or different. X < ^- > each represents an anion, and may be the same or different. ]
[In Formula (3), Z < ^- > represents an anion. ]   The method for removing a colored component according to claim 1, wherein a main component of the hardly biodegradable water-soluble colored component contained in the activated sludge mixed liquid is not a dye.   The said hardly biodegradable water-soluble coloring component contains at least 1 sort (s) of the water-soluble coloring polymer substance produced | generated by a humic substance, a lignin degradation product, a bilirubin-like substance, and an aminocarbonyl reaction. Removal method of coloring components.   The removal method of the coloring component as described in any one of Claims 1 thru | or 3 which adds 0.1-2000 mg / L of the said coloring component removal agent with respect to the said activated sludge liquid mixture. The amphoteric polymer is an amphoteric polymer containing a monomer unit represented by the following general formula (4) and a monomer unit represented by the general formula (5). The removal method of the coloring component as described in 2.
[In Formula (4), R ³ represents a hydrogen atom or a methyl group, R ⁴ represents an alkylene group having 1 to 4 carbon atoms, R ⁵ represents an alkyl group having 1 to 4 carbon atoms, and R ⁶ represents a hydrogen atom. represents an alkyl group or a benzyl group having 1 to 4 carbon atoms, a represents -O- or -NH-, Y ^- represents an anion. ]
Wherein ^{(5), R 7, R} 8 represents a hydrogen atom, a methyl group or a -COO ^- represents M '(. Representing a ⁺ M' ⁺ is a hydrogen ion or other cation), B represents a single bond, alkylene group, a phenylene group having 1 to 2 carbon atoms, -COOR ⁹ - ^{(R 9} represents an alkylene group having 2 to 6 carbon atoms) or ^{-CONHR 10} - ^(R 10 represents an alkylene group having 2 to 6 carbon atoms ), W ⁻ represents —COO ^— or —SO ₃ ^— , and M ⁺ represents a hydrogen ion or other cation. ]   The cationic polymer (a) contains 5 to 90 mol% of an amidine structural unit represented by the general formula (1) and / or an amidine structural unit represented by the general formula (2). The removal method of the coloring component as described in any one of these.   The cationic polymer (b) contains 10 to 100 mol% of a unit derived from the monomer represented by the general formula (3), according to any one of the coloring components according to any one of claims 1 to 6. Removal method.   The amphoteric polymer contains 10 to 98 mol% of the monomer unit represented by the general formula (4) and 2 to 30 mol% of the monomer unit represented by the general formula (5). The method for removing a colored component according to claim 5, which is an amphoteric polymer.