JP2016150312A - Coagulation treatment agent for waste water, and coagulation treatment method of waste water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coagulation treatment agent capable of forming an excellent coagulation flock even when the used amount of an agent is small, reducing a generation amount of sludge, reducing greatly chromaticity, and obtaining treated water having excellent water quality.SOLUTION: There is provided a coagulation treatment agent for waste water, which forms a coagulation flock by adding a polymer coagulant into the waste water, and then subjects the formed coagulation flock to solid-liquid separation. In the coagulation treatment agent for waste water, the polymer coagulant contains an amidine-based cationic polymer (A) and an amphoteric polymer (B), and the mixing ratio in terms of the mass between the polymer (A) and the amphoteric polymer (B) is 5:5 to 8:2.SELECTED DRAWING: None

Description

The present invention relates to a flocculation treatment agent for wastewater, and more specifically, even if the amount of chemical used is small, a good flocculation floc can be formed, the amount of sludge generated is reduced, the chromaticity is greatly reduced, and the water quality is good. The present invention relates to a flocculation treatment agent for wastewater from which treated water can be obtained.

Colored wastewater generated during beverage extraction and food processing, dyeing wastewater, washing wastewater for dust control products, laundry wastewater, and other wastewater generated from various factory facilities are generally coagulated with inorganic coagulants. After the addition, an anionic polymer flocculant is further added to form a floc floc for aggregation precipitation or pressurization under pressure. The purified treated water is generally discharged into rivers and sea areas.

Conventionally, the quality of treated water has been improved by improving wastewater treatment equipment and methods as countermeasures to strengthen regulations on the quality of discharged water to rivers and sea areas. However, colored wastewater often has high chromaticity even if BOD, SS, etc. satisfy the regulation values, and often gives a significant sense of contamination to local residents. Therefore, regulation of chromaticity may be set, and an efficient decoloring method for colored wastewater is strongly desired.

In general, the quality of treated water is aluminum sulfate (hereinafter referred to as “band”), polyaluminum chloride (hereinafter referred to as “PAC”), and ferric sulfate (hereinafter referred to as “polyiron”) used in coagulation and separation. ), And increase when the amount of inorganic coagulant such as ferric chloride is increased. However, the chromaticity can be removed to some extent by adding an inorganic coagulant, but it is often difficult to decolorize to a satisfactory level. Furthermore, since various substances causing coloration and various substances coexisting in the wastewater adversely affect the coagulation effect, the necessary amount of inorganic coagulant is increased in order to obtain stable decolorization performance. As a result, the amount of sludge generation increases and the overall treatment cost often increases.

In order to improve the decolorization of treated water, a treatment method has been proposed in which an organic coagulant, which is a kind of water-soluble cationic polymer, is applied to treated water. Since the organic coagulant is a polyelectrolyte having a large number of cationic groups in the molecule, it is used for the purpose of neutralizing the charge of the suspended substance in the water to be treated in the same manner as the inorganic coagulant. Organic coagulants are characterized by a higher cation density than inorganic coagulants and a higher molecular weight than inorganic coagulants, so that their coagulation and coagulation effects are much greater than inorganic coagulants. Organic coagulants not only neutralize suspended substances but also react with negatively charged dissolved substances such as lignin sulfonic acid and humic acid to form insoluble salts. And a reduction effect of COD is also expected.

Representative organic coagulants currently used are low molecular weight and strong compounds such as alkylamine / epichlorohydrin condensate, alkylene dichloride and polyalkylene polyamine condensate, dicyandiamide / formalin condensate, and dimethyldiallylammonium chloride polymer. Examples thereof include water-soluble polymers having a cation density. In the prescription using these organic coagulants, although a certain degree of decoloring effect is obtained, a satisfactory decoloring effect is often not obtained for various colored wastewaters.

Waste water purification by agglomeration treatment is performed by neutralizing charge by reacting negatively charged dissolved substances (suspended substances, colloidal substances, BOD and COD components, etc. in waste water) with inorganic coagulants and organic coagulants. This is accomplished by agglomeration and separation after insolubilization.

Suspended substances and colloidal substances have a relatively large particle size and are insoluble in water, and therefore, when charged and neutralized, they condense and form fine flocs. However, coloring substances such as dyes that are highly soluble in water are dissolved in water while retaining some hydrophilicity even when neutralized by adding inorganic and organic coagulants. Therefore, there is a case where fine flocs are not formed without insolubilization. Therefore, even when a polymer flocculant is added, aggregated flocs are not formed, the colored substance is dissolved in water, and the decoloring effect of the treated water is often not obtained.

An amidine-based cationic polymer containing an amidine structural unit (hereinafter referred to as “amidine polymer”) has a high cation density and has excellent performance in the action of charge neutralization and cross-linking adsorption. Therefore, by adding an amidine polymer, It is known that coloring substances such as dyes are insolubilized, and as a result, a good decoloring effect can be obtained. This is a peculiar effect of the amidine polymer. While neutralizing the negatively charged coloring substance, the amidine polymer reacts with an ionic component other than the coloring substance to form an ion complex, and the coloring substance is involved. Since it is insolubilized, the coloring substance is well insolubilized and the decoloring effect is improved.

As a coagulation treatment method of colored wastewater using amidine polymer, for example, an inorganic coagulant and an amidine polymer are added to colored wastewater and then coagulated and separated using an anionic polymer coagulant (Patent Document 1), coloring There has been proposed a method (Patent Document 2) in which an inorganic solid powder such as zeolite or activated carbon powder is added as an insoluble adsorbent to waste water, and then an amidine polymer and a diallylamine cationic polymer are added and agglomerated and separated. Although these methods can provide a good decoloring effect, since both methods use a large amount of inorganic additives, the amount of sludge generated after agglomeration and separation increases, and the processing cost increases.

As a treatment method for coagulating colored wastewater using an organic coagulant or an organic polymer flocculant without using an inorganic additive, for example, a suspended solid (hereinafter referred to as “SS”) concentration of 500 mg / A method of adding an amidine polymer and a diallylamine cationic polymer to a colored wastewater that is L or more and aggregating and separating (Patent Document 3), adding a dicyandiamide / formalin condensate to a food processing colored wastewater, and then mixing excess sludge; Furthermore, a method (Patent Document 4) has been proposed in which a polymer flocculant containing an amidine polymer is added to perform flocculation separation.

In general, when a polymer flocculant is added to a colored wastewater to perform a flocculation treatment, the colored components are first insolubilized by neutralization with an inorganic coagulant or an organic coagulant to become a nucleus. Thereafter, fine flocs are formed by the action of the flocculant while entraining the insolubilized coloring component. For this reason, the higher the SS concentration of colored wastewater, the better the aggregation performance. Each of the above methods is a coagulation treatment method effective for colored wastewater having an SS concentration equal to or higher than a predetermined concentration, or colored wastewater having an SS concentration adjusted to a predetermined concentration, but colored wastewater having a low SS concentration. On the other hand, since the cohesiveness is deteriorated, the decoloring effect is lowered.

JP 2012-5993 A JP 2011-50945 A JP 2011-50946 A JP 2001-162285 A

In agglomeration treatment of wastewater, even when the amount of chemical used is small, a good agglomeration floc can be formed, the amount of sludge generated is reduced, the chromaticity is greatly reduced, and a treated water with good water quality can be obtained. It is to provide an agent.

In view of the above circumstances, the present inventors have obtained the following knowledge as a result of earnest search.
That is, in the case of colored wastewater having the above-mentioned properties, the neutralization of the negatively charged soluble colored substance by the amidine polymer and the anionic or amphoteric organic polymer other than the colored substance contained in the wastewater An ionic component composed of a component or an anionic component derived from an inorganic salt reacts with the amidine polymer to form an ion complex, and insolubilizes the colored material, thereby insolubilizing the colored material well. However, after that, the insoluble colored substance forms fine flocs, and further increases the amount of the amidine polymer required for coarsening to flocs having a floc diameter effective for flocculation and separation. Therefore, by mixing and using an amidine polymer and a specific amphoteric polymer, the amount of amidine polymer added does not increase, and the insoluble colored substance forms a fine floc, and the fine floc becomes coarse and agglomerated floc It was found that the reaction of growing rapidly progresses.

When the colored wastewater is agglomerated with a mixture of the amidine polymer and the amphoteric polymer, the colored substance is insolubilized by the amidine polymer if the ratio of the amphoteric polymer to the total mass of the amidine polymer and the amphoteric polymer is within a predetermined range. Furthermore, by reacting with the amphoteric polymer to form a crosslinked structure, the insoluble colored substance forms fine flocs, and the fine flocs grow into coarse aggregated flocs. For this reason, a favorable aggregation floc is obtained and the decoloring effect of colored wastewater is improved.

That is, the wastewater flocculation treatment agent of the present invention is a wastewater flocculation treatment agent for adding a polymer flocculant to wastewater to form agglomeration floc, and then solid-liquid separating the formed agglomeration floc. Waste water in which the molecular flocculant contains an amidine-based cationic polymer (A) and an amphoteric polymer (B), and the mixing ratio as a mass of the polymer (A) and the amphoteric polymer (B) is 5: 5 to 8: 2. It is a coagulation treatment agent.

Moreover, the coagulation treatment agent for wastewater of the present invention is a polymer in which the amidine-based cationic polymer (A) has an amidine structural unit represented by either the following general formula (1) or the following general formula (2). It is a coagulation treatment agent for the waste water.

(In the general formulas (1) and (2), R ¹ and R ² each independently represent a hydrogen atom or a methyl group, and X ⁻ represents an anion.)

Further, the coagulation treatment agent for wastewater of the present invention is a polymer in which the amphoteric polymer (B) has a cationic structural unit represented by the following general formula (3), an anionic structural unit, and a nonionic structural unit. It is a coagulation treatment agent for certain waste water.

(Wherein R ³ represents a hydrogen atom or a methyl group, R ⁴ and R ⁵ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ⁶ has 1 carbon atom) represents to 4 alkyl group or a benzyl group, Y represents an oxygen atom or NH, Z ^- represents an anion, n is an integer of 1 to 3).

Moreover, the coagulation treatment agent of the wastewater of the present invention is the coagulation treatment agent of the above wastewater in which the reduced viscosity at 25 ° C. of the 1N sodium chloride aqueous solution of the amphoteric polymer (B) is 0.1 to 10 dL / g.

Further, in the wastewater flocculation treatment agent of the present invention, the ratio of the anionic structural unit of the amphoteric polymer (B) to all structural units is Ma mol%, and the ratio of the cationic structural unit to all structural units is Mc mol%. When the waste water is aggregated, the ratio Ma / Mc is 0.15 to 0.55.

Moreover, the flocculation treatment agent of the waste water of the present invention contains the non-amidine cationic polymer (C) as a polymer flocculant in addition to the amidine cationic polymer (A) and the amphoteric polymer (B). It is a coagulation treatment agent for wastewater.

The coagulation treatment agent for wastewater of the present invention is a non-amidine cationic polymer in which the non-amidine cationic polymer (C) contains 60 to 100 mol% of a cationic monomer unit represented by the following general formula (4). It is a coagulation treatment agent of the said wastewater which is.

(Wherein R ³ represents a hydrogen atom or a methyl group, R ⁴ and R ⁵ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ⁶ has 1 carbon atom) represents to 4 alkyl group or a benzyl group, Y represents an oxygen atom or NH, Z ^- represents an anion, n is an integer of 1 to 3).

Further, the flocculation treatment agent of the waste water of the present invention is the amidine-based cationic polymer in the total amount of the amidine-based cationic polymer (A), the amphoteric polymer (B) and the non-amidine-based cationic polymer (C). The waste water flocculating agent is a ratio of the total amount of (A) and the amphoteric polymer (B) to the non-amidine cationic polymer (C) of 8: 2 to 5: 5.

Moreover, the coagulation treatment method of the wastewater of the present invention is a coagulation treatment method of wastewater using the coagulation treatment agent according to any one of the above.

Furthermore, the wastewater flocculation treatment method of the present invention is the wastewater flocculation treatment method, wherein the wastewater is colored wastewater.

According to the flocculation treatment agent of the present invention, in the flocculation treatment of wastewater, even if the amount of chemical used is small, a good flocculation floc can be formed, the generation amount of sludge is reduced, and the chromaticity is greatly reduced. It is possible to provide an aggregating treatment agent capable of obtaining treated water with good water quality.

Hereinafter, the present invention will be described in detail.
“Coloring substance” means a water-soluble coloring substance.
“Colored wastewater” means wastewater containing colored substances, and may contain suspended substances, colloidal substances, ionic components and the like in addition to colored substances.
The “ionic component” means an anionic component derived from an anionic or amphoteric organic polymer component or inorganic salt other than a coloring substance contained in colored wastewater.
“Floating solid matter (SS)” means a substance remaining on a filter medium when colored wastewater is filtered with a filter medium having a pore diameter of 1 μm according to JIS K 0102: 2008.
A “structural unit” is a structural unit derived from a monomer molecule formed by polymerization of a monomer, or a pendant group formed by reaction of a pendant group of a structural unit derived from a monomer molecule with a pendant group of a structural unit derived from another monomer molecule. It means a structural unit composed of structural units derived from two or more monomer molecules in which groups are linked.
"Aggregating agent" means a drug that has the function of aggregating colored substances, suspended substances other than colored substances, colloidal substances, ionic components, etc. contained in colored wastewater to form fine flocs and aggregated flocs. To do.
“Polymer” means a compound having a structure composed of a plurality of structural units.
“Agglomeration” is a process that agglomerates colored substances contained in colored wastewater, suspended substances other than colored substances, colloidal substances, ionic components, etc. to form fine flocs, and further grows fine flocs into aggregated flocs. This means that the treated flocculant is separated to obtain treated water.
"Fine floc" means a negatively charged water-soluble colored substance that has become insoluble due to charge neutralization and agglomerates to form fine aggregates. It may include particles in which water-insoluble particles such as substances are neutralized by charge and aggregate to form fine aggregates.
The “aggregated floc” means a fine floc further agglomerated and coarsened to a floc diameter necessary for aggregating and separating.
The “SS concentration” means a value measured using glass fiber filter paper having a pore diameter of 1 μm as a filter medium according to the measurement method described in JIS K 0102: 2008.
“COD” means pollution of wastewater by organic matter or inorganic matter containing a coloring substance, and is used as an index of the content of the coloring substance in the present invention. The value of COD means a value measured according to the CODMn analysis method described in JIS K 0102: 1998.
“Electrical conductivity” means an index indicating the amount of various ions and salts in colored wastewater. The value of electrical conductivity means a value measured according to the electrical conductivity measurement method described in JIS K 0102: 1998.

(Coagulation treatment method for colored wastewater)
In the flocculation treatment of colored wastewater, a polymer flocculant composed of a mixture containing a specific amidine polymer (A) and an amphoteric polymer (B) is added to the colored wastewater to form flocculated flocs, and then the formed flocculated flocs are solidified. Separate the liquid.

(Colored wastewater)
The colored wastewater targeted by the present invention includes, for example, colored wastewater generated in beverage manufacturing processes and food processing processes, dyeing wastewater, washing wastewater for dust control products, washing wastewater, and other color generated from various factory facilities. Examples include waste water.

The colored substance contained in the colored wastewater is a water-soluble colored substance, and the value of COD can be used as an index of the content of the colored substance. The COD of the colored wastewater is preferably 50 to 3000 mg / L.

The colored wastewater flocculation treatment method of the present invention is also suitably applied to colored wastewater having an SS concentration of 450 mg / L or less.

The SS concentration of colored wastewater is preferably 20 mg / L or more, more preferably 50 mg / L or more. Moreover, 450 mg / L or less is preferable, 250 mg / L or less is more preferable, and 200 mg / L or less is further more preferable. When the SS concentration of the colored wastewater is within the above range, the colored substance is efficiently insolubilized, a good aggregated floc is formed, and a good decoloring effect is obtained.

The colored wastewater targeted by the present invention contains a lot of inorganic salts. Examples of the inorganic salt include an inorganic salt originally contained in wastewater, an inorganic salt formed by decomposing organic matter by biological treatment, and a coagulating sedimentation and addition performed in a step preceding the treatment facility for colored wastewater of the present invention. Examples thereof include inorganic salts derived from inorganic agents such as inorganic coagulants used in wastewater treatment such as pressure levitation. Although it does not specifically limit as an inorganic salt in colored wastewater, A sulfate, a phosphate, a silicate, etc. are mentioned. The electrical conductivity of colored wastewater can be used as an index indicating the amount of inorganic salt contained in the wastewater, and since the colored wastewater targeted by the present invention contains a large amount of inorganic salt, the electrical conductivity is high. The value is preferably 0.5 mS / cm or more, and more preferably 1.0 mS / cm or more. Moreover, 50 mS / cm or less is preferable and 30 mS / cm or less is more preferable.

(Polymer flocculant)
In the present invention, a specific amidine polymer (A) and a specific amphoteric polymer (B) are used in combination as a polymer flocculant.

In order to insolubilize the colored substance efficiently, to form a good aggregated floc and to obtain an excellent dehydration effect, it is necessary to use the amidine polymer (A) and the amphoteric polymer (B) at a predetermined mixing ratio. That is, as for the mixing ratio, the ratio of the amidine polymer (A) to the total mass of each polymer is 50 to 80% by mass, and the ratio of the amphoteric polymer (B) is 20 to 50% by mass. If the mixing ratio, the insoluble coloring component aggregates to form fine flocs and the growth reaction from fine flocs to agglomerated flocs proceeds efficiently, and good aggregated flocs are formed. Is improved.

When the ratio of the amphoteric polymer (B) to the total mass of the polymers (A) and (B) exceeds 50% by mass, a part of the functional group showing the cationic property of the amidine polymer in the stage where fine flocs are formed Then, a part of the functional group showing anionic property of the high-viscosity amphoteric polymer (B) reacts to immediately form self-crosslinks and insolubilize, so that the formation reaction of fine flocs is suppressed. On the other hand, when the ratio of the amphoteric polymer (B) to the total mass of the polymers (A) and (B) is 20% by mass or less, the cohesiveness of the insolubilized colored substance is lowered and a good aggregated floc is formed. In order to do this, the required amount of the polymer flocculant added increases.

The amidine polymer (A) contains an amidine structural unit represented by at least one of the general formula (1) and the general formula (2). The content of the amidine structural unit in the amidine polymer (A) is usually preferably 30 mol% or more, and more preferably 40 mol% or more. Moreover, 90 mol% or less is preferable and 80 mol% or less is more preferable. If it is in the said range, a coloring substance will be insolubilized efficiently, a favorable aggregation floc can be formed, and the decoloring effect will be improved.

A method for producing the amidine polymer (A) is not particularly limited, and an ethylenically unsaturated monomer having an amino group or a substituted amino group capable of forming an amino group by a conversion reaction, and a nitrile such as acrylonitrile or methacrylonitrile; And a method in which a cyano group and an amino group in the copolymer are reacted under acidic conditions to form an amidine.

Examples of the ethylenically unsaturated monomer include CH ₂ ═CR ⁷ —NHCOR ⁸ (wherein R ⁷ is a hydrogen atom or a methyl group, and R ⁸ is an alkyl group having 1 to 4 carbon atoms). It is preferably a compound represented by the following formula: The copolymer is easily converted to an amino group by hydrolysis or alcoholysis. In addition, this amino group reacts with the adjacent cyano group to amidinate. Specific examples of the compound represented by the general formula (5) include N-vinylformamide (R ⁷ = H, R ⁸ = H), N-vinylacetamide (R ⁷ = H, R ⁸ = CH ₃ ). Etc.

The use ratio of the ethylenically unsaturated monomer and the nitrile in the copolymer is usually preferably 20:80 to 80:20, more preferably 40:60 to 60:40 in terms of molar ratio.

The amidine polymer (A) is most typically an amino acid formed by hydrolysis by copolymerizing N-vinylformamide and acrylonitrile in the presence of hydrochloric acid as described above. It is produced by forming an amidine building block from a cyano group adjacent to the group. In this case, the amidine polymer (A) having various compositions can be obtained by appropriately selecting the molar ratio of N-vinylformamide and acrylonitrile to be subjected to copolymerization and the amidine formation conditions of the copolymer. The amidine polymer (A) may be selected from commercially available products.

As a physical property value showing the viscosity of the amidine polymer (A), the reduced viscosity at 25 ° C. (hereinafter referred to as “reduced viscosity”) of a 1 N sodium chloride aqueous solution containing 0.1 g / dL of the amidine polymer (A) is usually used. Is preferably 0.1 dL / g or more, more preferably 1 dL / g or more. Moreover, 10 dL / g or less is preferable and 5 dL / g or less is more preferable.

The amphoteric polymer (B) is a polymer having a structural unit represented by the general formula (3) as a cationic structural unit. As the cationic structural unit, for example, a cationic structural unit derived from an amine salt or alkyl chloride quaternary salt of a dialkylaminoalkyl (meth) acrylate which is a cationic monomer, or an amine salt of dialkylaminoalkyl (meth) acrylamide or Examples include cationic structural units derived from alkyl chloride quaternary salts. In particular, dialkylaminoalkyl (meth) acrylate alkyl chloride quaternary salts are preferred. As the monomer, one type of cationic monomer may be used alone, or two or more types may be used in combination.

The content of the cationic structural unit in the amphoteric polymer (B) is usually preferably 25 mol% or more. Moreover, 80 mol% or less is preferable and 55 mol% or less is more preferable. With the amphoteric polymer (B) having such a constitutional unit, a reaction in which insoluble colored substances are aggregated to form fine flocs and a reaction in which the fine flocs grow into the aggregated flocs proceed efficiently, and good aggregated flocs are obtained. Is formed, and the decolorization effect is improved.

The amphoteric polymer (B) is a polymer having an anionic structural unit, and examples of the structural unit having an anionic functional group include (meth) acrylic acid and 2-acrylamido-2methylpropanesulfonic acid. Of these, acrylic acid is preferred. The content of the anionic structural unit in the amphoteric polymer (B) is usually preferably 3 mol% or more, and more preferably 5 mol% or more. Moreover, 75 mol% or less is preferable and 30 mol% or less is more preferable.

The amphoteric polymer (B) is a polymer having a nonionic structural unit in addition to the cationic structural unit and the anionic structural unit, and examples of the nonionic structural unit include (meth) acrylamide. The content of nonionic structural units in the amphoteric polymer (B) is usually 1 to 70 mol%.

The reduced viscosity of the amphoteric polymer (B) is usually preferably 0.1 dL / g or more, and more preferably 3.0 dL / g or more. Moreover, 10.0 dL / g or less is preferable and 7.5 dL / g or less is more preferable. If the reduced viscosity of the amphoteric polymer (B) is within the above range, a part of the functional group showing the cationic property of the amidine polymer and a part of the functional group showing the anionic property of the amphoteric polymer at the stage of growing into an aggregated floc. Reacts efficiently, so that good coagulation flocs are formed and the decolorization effect of colored wastewater is improved.

When the content of the anionic structural unit of the amphoteric polymer (B) is Ma mol% and the content of the cationic structural unit is Mc mol%, the ratio of the content of the anionic structural unit to the cationic structural unit Ma / Mc (hereinafter referred to as “A / C”) is usually preferably 0.15 or more, and more preferably 0.25 or more. Moreover, 0.55 or less is preferable and 0.45 or less is more preferable. If A / C is within the above range, the amphoteric polymer (B) causes the insoluble colorant to aggregate to form fine flocs, and the growth reaction from fine flocs to agglomerated flocs proceeds efficiently and is favorable. Agglomerated flocs are formed and the decolorization effect of colored wastewater is improved.

The colored wastewater targeted by the present invention contains a lot of inorganic salts, and these inorganic salts are often mixed as 1 to 3 anions, that is, anionic components in the wastewater. The amidine polymer (A) can efficiently insolubilize the colored substance by reacting with the anionic component derived from these inorganic salts and the colored substance to neutralize the charge and form an ion complex. The colored substance insolubilized by the amidine polymer (A) then grows from fine flocs to agglomerated flocs by cross-linking adsorption of the amphoteric polymer (B), and good agglomerated flocs are formed. In the coagulation treatment method of the colored wastewater according to the present invention, the non-amidine-based cationic polymer (hereinafter referred to as “cationic polymer”) (C) is used in combination so that the function of cross-linking adsorption of the amphoteric polymer (B) is achieved. The polymer flocculant preferably contains a cationic polymer (C) in order to improve and form a better aggregated floc.

The cationic polymer (C) is a polymer having a structural unit represented by the general formula (3) as a cationic structural unit. As the cationic structural unit, for example, a cationic structural unit derived from an amine salt or alkyl chloride quaternary salt of a dialkylaminoalkyl (meth) acrylate which is a cationic monomer, or an amine salt of dialkylaminoalkyl (meth) acrylamide or Examples include cationic structural units derived from alkyl chloride quaternary salts. In particular, dialkylaminoalkyl (meth) acrylate alkyl chloride quaternary salts are preferred. As the monomer, one type of cationic monomer may be used alone, or two or more types may be used in combination.

The content of the cationic structural unit in the cationic polymer (C) is usually preferably 60 mol% or more, and more preferably 80 mol% or more. Moreover, 100 mol% or less is preferable. The cationic structural unit includes at least 60 to 100 mol% of a dimethylaminoethyl acrylate methyl chloride quaternary salt monomer structural unit and a dimethylaminoethyl methacrylate methyl chloride quaternary salt monomer structure as a proportion of the total structural units. It is preferable to contain 0-30 mol% of units. In the cationic polymer (C) having such a structural unit, a good aggregation floc is obtained and the dehydration effect is improved.

The cationic polymer (C) is a polymer containing a nonionic structural unit, and examples of the nonionic structural unit include (meth) acrylamide. The content of the nonionic structural unit in the nonamidine-based cationic polymer (C) is usually 1 to 70 mol%.

In order to efficiently insolubilize the colored substance, form a good aggregated floc, and obtain an excellent dehydration effect, a mixture of the amidine polymer (A) and the amphoteric polymer (B) and the cationic polymer (C) are mixed at a predetermined mixing ratio. It is necessary to use it. That is, the mixing ratio is 50 to 80% by mass of the mixture of the amidine polymer (A) and the amphoteric polymer (B) with respect to the total mass of the mixture of the amidine polymer (A) and the amphoteric polymer (B) and the cationic polymer (C). The ratio of the cationic polymer (C) is 20 to 50% by mass. With such a mixing ratio, the insoluble coloring component aggregates to form fine flocs and the growth reaction from fine flocs to aggregated flocs proceeds efficiently, and good aggregated flocs are formed. Decolorization effect is improved.

The production method of the amphoteric polymer (B) and the cationic polymer (C) is not particularly limited, but an aqueous monomer solution in which the above monomer is dissolved in water is made into a uniform sheet, and visible light or ultraviolet light is used using a photoinitiator. Aqueous photopolymerization method for copolymerization by irradiation, adiabatic polymerization method for obtaining an aqueous gel polymer by adding one or more initiators to an aqueous monomer solution, and dispersing an aqueous monomer solution in a non-aqueous solvent Methods such as a dispersion polymerization method for polymerization and an emulsion polymerization method for emulsifying an aqueous monomer solution using an emulsifier in a non-aqueous solvent can be appropriately selected. In the case of photopolymerization, adiabatic polymerization, and the like, the polymer is obtained as an aqueous gel. Therefore, it is preferable to pulverize and dry the aqueous gel into a powder.

The method for preparing the above-mentioned reduced viscosity amphoteric polymer (B) is not particularly limited, but is appropriately selected in consideration of the viscosity of the polymer for producing conditions such as polymerization time, polymerization temperature, and chain transfer agent addition amount in the production process. To do. In the present invention, it is preferable to adjust the reduced viscosity according to the condition of the chain transfer agent addition amount. The type of chain transfer agent is not particularly limited, and examples thereof include thiol compounds such as mercaptoethanol and mercaptopropionic acid, and reducing inorganic salts such as sodium sulfite, sodium bisulfite, and sodium hypophosphite. Of these, sodium hypophosphite is particularly preferable. The addition amount of the chain transfer agent is usually 1 to 3000 ppm with respect to all raw materials monomers.

In the present invention, known methods can be applied as a method for adding the polymer flocculant to the colored waste water and the method for forming the floc floc.

As a method for adding the polymer flocculant, it is preferable to dissolve the polymer flocculant in water at a concentration of 0.05 to 0.5% by mass and then add it to the colored waste water. Further, the polymer flocculant is preferably added as a one-drug agent in which the amidine polymer (A), the amphoteric polymer (B), and the cationic polymer (C) are mixed. In some cases, the polymer flocculant may be added to the colored waste water in the form of a powder.

The polymer flocculant may contain other cationic polymers and amphoteric polymers other than the amidine polymer (A), the amphoteric polymer (B), and the cationic polymer (C) as long as the effects of the present invention are not impaired. The mixing ratio of the other cationic polymer and amphoteric polymer is preferably less than 10% by mass, more preferably less than 5% by mass, and still more preferably 0% by mass with respect to the total mass of the polymer flocculant.

In the flocculation treatment method of the colored wastewater of the present invention, in order to form a better flocculation floc, if necessary, after adding a polymer flocculant of the colored wastewater, an anionic polymer (hereinafter referred to as “anionic polymer”). A polymer flocculant consisting of (D) may be added.

The anionic polymer (D) is a polymer having an anionic structural unit. Examples of the anionic structural unit include (meth) acrylic acid and 2-acrylamido-2methylpropanesulfonic acid. Among these, acrylic acid is preferable. The content of the anionic structural unit in the anionic polymer (D) is usually 5 to 90 mol%. Furthermore, the anionic polymer (D) is a polymer having a nonionic structural unit, and examples of the nonionic structural unit include (meth) acrylamide. Content of the nonionic structural unit in an anionic polymer (D) is 10-95 mol% normally.
Although it does not specifically limit as a manufacturing method of an anionic polymer (D), A precipitation polymerization method, a block polymerization method, a dispersion polymerization method, an aqueous solution polymerization method etc. are mentioned.

When adding the polymer flocculant, it is preferable to stir the colored wastewater. If the stirring is too weak, the polymer flocculant is not uniformly mixed, and if the stirring is too strong, the fine flocs are difficult to grow into the aggregated flocs. Therefore, when adding the polymer flocculant, it is preferable to stir the colored waste water at a rotational speed of 180 to 3000 rpm.

An acidic substance may be added in order to improve the solubility of the polymer flocculant in water and to prevent deterioration such as a decrease in the viscosity of the aqueous solution of the polymer flocculant. Examples of the acidic substance include sulfamic acid and acidic sodium sulfite.

The method for solid-liquid separation of the aggregate flocs is not particularly limited, and examples thereof include methods such as aggregation precipitation, flotation separation, centrifugation and filtration, and solid-liquid separation is preferably performed by aggregation precipitation or flotation separation.

The amount of polymer flocculant added varies depending on the concentration of colored wastewater, suspended substances, colloidal substances, ionic components, etc. in the colored wastewater, but it cannot be said unconditionally. On the other hand, the amount is 1 to 500 ppm.

In the present invention, in addition to the polymer flocculant, an inorganic coagulant and / or an organic coagulant (hereinafter collectively referred to simply as “coagulant”) may be used in combination. Even if it uses together with the said coagulant | flocculant, the said polymer flocculent can fully exhibit the decoloring effect with respect to colored wastewater. Examples of the inorganic coagulant include sulfuric acid band, polyaluminum chloride, ferric chloride, ferrous sulfate, ferric sulfate, polyiron (polyiron sulfate, polyiron chloride) and the like. Examples of the organic coagulant include polyamine, polydiallyldimethylammonium chloride, alkyl chloride quaternary salt of polydialkylaminoalkyl methacrylate, and a cationic surfactant.

The timing of adding the coagulant is not particularly limited, but it is preferably added in the step before adding the polymer flocculant. The addition amount of the coagulant is usually 5 to 3000 parts by mass with respect to 100 parts by mass of the polymer flocculant of the present invention.

EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example and a comparative example, this invention is not limited by the following description, unless the summary is exceeded. In the examples and comparative examples, “%” indicates “% by mass” unless otherwise specified. About each polymer obtained by the following manufacture examples, the reduced viscosity shown below was measured. For the measurement, a powdery polymer flocculant was used.

[Measurement of reduced viscosity]
The reduced viscosity was measured with an Ostwald viscometer at 25 ° C. as a 0.1 g / dL polymer solution in a 1 N aqueous sodium chloride solution.

The raw materials used in the examples are shown below.
[monomer]
(I) Cationic monomer:
(A) N, N-dimethylaminoethyl acrylate methyl chloride quaternary salt (hereinafter referred to as “DME”), manufactured by Osaka Organic Chemical Industry Co., Ltd., 80 mass% aqueous solution (b) N, N-dimethylaminoethyl methacrylate methyl chloride Quaternary salt (hereinafter referred to as “DMC”), manufactured by Osaka Organic Chemical Industry Co., Ltd., 80% by weight aqueous solution (ii) anionic monomer:
Acrylic acid (hereinafter referred to as “AA”), manufactured by Mitsubishi Chemical Corporation, 50 mass% aqueous solution (iii) nonionic monomer:
(A) Acrylamide (hereinafter referred to as “AAM”), manufactured by Daianitrix Co., Ltd., 50% by mass aqueous solution (b) Acrylonitrile (hereinafter referred to as “AN”), manufactured by Daianitrix Co., Ltd., purity 99% by mass
(C) N-vinylformamide (hereinafter referred to as “NVF”), manufactured by Diaanitrix, 91 mass% aqueous solution [initiator]
(I) 2-hydroxy-2-methyl-1-phenylpropan-1-one (DAROCUR1173) (hereinafter referred to as “D-1173”), (ii) 2,2′-azobis (2- Amidinopropane) dihydrochloride (V-50) (hereinafter referred to as “V-50”), manufactured by Wako Pure Chemical Industries, Ltd. [chain transfer agent]
Sodium hypophosphite (hereinafter referred to as “HPA”), manufactured by Wako Pure Chemical Industries, Ltd.

[Synthesis of Amidine Polymer (A)]
(Production Example 1)
A mixture of 6 g of AN and NVF (molar ratio 55:45) and 34 g of distilled water was placed in a 50-mL four-necked flask equipped with a stirrer, a nitrogen introduction tube, and a cooling tube. While stirring in nitrogen gas, the temperature was raised to 60 ° C., 0.12 g of V-50 was added, and the mixture was further maintained at 60 ° C. for 3 hours to obtain a suspension in which the polymer was precipitated in water. 20 g of distilled water was added to the suspension, and 1 equivalent 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 resulting polymer gel was chopped, dried at 60 ° C. for one day and night, and pulverized to obtain an amidine polymer (A) (polymer A-1).

Polymer A-1 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 constituent 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.

(*) Amidine: Amidine hydrochloride structural unit, NVF: N-vinylformamide structural unit, AN: Acrylonitrile structural unit, VAM: Vinylamine hydrochloride structural unit

[Synthesis of Amphoteric Polymer (B)]
(Production Example 2)
632.9 g of DME, 100.0 g of AA, and 900.0 g of AAM were put into a 2000 mL brown heat-resistant bottle, 3.0 g of HPA and distilled water were added, and a monomer aqueous solution (DME: total mass of 2000 g) was added. AA: AAM = 26.9: 7.2: 65.9 (mol%), monomer concentration 50%) was prepared. Furthermore, D-1173 was added so that it might become 150 ppm with respect to the total mass of monomer aqueous solution, and the temperature of monomer aqueous solution was adjusted to 20 degreeC, blowing nitrogen gas into this for 30 minutes.

Thereafter, the monomer aqueous solution is transferred to a stainless steel reaction vessel, and the surface temperature becomes 40 ° C. with an irradiation intensity of 5 W / m ² from above the vessel using a chemical lamp while spraying water at 16 ° C. from below the vessel. It was irradiated with light. After the surface temperature reached 40 ° C., light was irradiated for 30 minutes at an irradiation intensity of 0.3 W / m ² . Furthermore, in order to reduce the residual amount of monomer, irradiation was performed for 10 minutes at an irradiation intensity of 50 W / m ² . Thereby, a hydrogel polymer was obtained. The obtained hydrogel polymer was taken out from the container, crushed using a small meat chopper, and then dried at a temperature of 60 ° C. for 16 hours. Thereafter, the dried polymer was pulverized using a Willet pulverizer to obtain an amphoteric polymer (B) (polymer B-a1).

(Production Examples 3 to 20)
In Production Example 2, the amount of each monomer and HPA was adjusted, and the same operation as in Production Example 2 was carried out except that the ratios shown in Table 2 were changed, and the amphoteric polymer (B) (Polymers B-a2 to a4, b1-b3, c1-c3, d1-d3, e1, e2, f1, f2, g1, g2) were obtained.

[Synthesis of Cationic Polymer (C)]
(Production Examples 21 to 24)
In Production Example 2, the amount of each monomer and HPA was adjusted, and the same operation as in Production Example 2 was carried out except that the ratios shown in Table 3 were changed, and the cationic polymer (C) (Polymers C-1 to 4) Got.

[Preparation of polymer flocculant]
(Production Examples 25-56)
The polymers described in Tables 1 to 3 were mixed and prepared at the mixing ratios described in Tables 4 to 6 to obtain polymer flocculants (Blends 1 to 32) described in Tables 4 to 6.

[Measurement of SS concentration of colored wastewater]
The SS concentration of colored wastewater was measured by the above-described method for measuring the SS concentration of colored wastewater.

[Measurement of COD of colored wastewater]
The COD of the colored wastewater was measured by the above-described COD _Mn measuring method.

[Measurement of electrical conductivity of colored wastewater]
The electrical conductivity of the colored wastewater was measured by the above-described method for measuring electrical conductivity.

(Examples 1 to 19)
[Use colored wastewater]
As colored wastewater generated from the wastewater treatment facility of the food industry, wastewater having the following characteristics was used in the wastewater treatment facility of the beverage extraction factory of H Co., Ltd. That is, a colored wastewater having a pH of 7.31, an SS concentration of 340 mg / L, an electric conductivity of 1.7 mS / cm, and a COD of 390 mg / L, measured using an analysis method described in JIS standards. .

[Aggregation test]
First, 500 mL of the colored waste water was collected in a 500 mL beaker. Next, a polymer flocculant described in Tables 4 to 6 was dissolved in 0.3% to prepare an aqueous polymer flocculant solution, which was added to the concentration shown in Table 7, and then stirred with a jar tester. Aggregation flocs were formed by stirring and mixing under conditions of speed: 180 revolutions / minute, stirring time: 60 seconds. Thereafter, the aggregated floc was precipitated, and the aggregated floc and treated water were separated. Table 7 shows the evaluation results described later.

(Comparative Examples 1-7)
Except that the polymer flocculant used was changed as shown in Table 8, agglomerated floc was formed in the same manner as in Example 1 to separate the agglomerated floc and treated water. Table 8 shows the evaluation results described later.

[Evaluation method]
[Agglomerated floc particle size, SS concentration of treated water, COD of treated water]
In each of the examples and comparative examples, after agglomeration floc was formed, stirring was stopped, and the agglomeration floc particle diameter and treated water SS concentration were visually measured. Thereafter, the treated water was collected and the COD of the treated water was measured. The COD of the treated water was measured by the above-described COD _Mn measuring method in the same manner as the COD of the colored wastewater.

[SS concentration of treated water]
About the SS density | concentration of treated water, it evaluated by the following reference | standard by visual observation.
A: The treated water after separating the aggregated floc is almost transparent, and almost no suspended matter is seen (SS concentration guideline: less than 10 mg / L).
B: Some turbidity is seen in the treated water after separating the flocs and flocs are present slightly (SS concentration guideline: 10 mg / L or more and less than 50 mg / L).
C: Turbidity is partially observed in the treated water after separating the aggregated flocs, and suspended matter is present in some places (SS concentration guideline: 50 mg / L or more and less than 100 mg / L).
D: Many turbidity is seen in the treated water after separating the aggregated floc, and the suspended matter is present as a whole (SS concentration guideline: 100 mg / L or more and less than 300 mg / L).
E: Numerous turbidity is generally observed in the treated water after separating the aggregated floc, and the suspended matter is present entirely and partially in a large size (SS concentration guideline: 300 mg / L or more and 500 mg) / L).
X: The treated water after separating the flocs flocs is completely turbid, and there are many coarse suspended matters (SS concentration guideline: 500 mg / L or more).

As shown in Table 7, in Examples 1 to 19 using the polymer flocculant of the present invention, coarse aggregated flocs were formed and the SS concentration of treated water was low. In particular, Examples 1-4 in which the reduced viscosity of the amphoteric polymer (B) is in the range of 3.0 to 7.5 dL / g and A / C is in the range of 0.25 to 0.45, A coarse coagulated floc having a large floc diameter was obtained, and treated water having a low quality COD and a high quality water was obtained.

As shown in Table 8, Comparative Examples 1 to 7 are examples using a polymer flocculant in which the mixing ratio of each polymer deviates from the range of the predetermined ratio of the present invention. The SS concentration and COD of water were high.

(Examples 20 to 31, Comparative Examples 8 and 9)
[Use colored wastewater]
As the colored wastewater generated from the wastewater treatment facility of the dust control industry, the wastewater having the following characteristics was used in the colored wastewater collected at the wastewater treatment facility of the cleaning factory of T Corporation. That is, a colored wastewater having a pH of 7.56, an SS concentration of 157 mg / L, an electric conductivity of 1.98 mS / cm, and a COD of 580 mg / L measured using an analysis method described in JIS standards. .

(Aggregation test)
The same aggregation test as in Example 1 was performed except that the polymer flocculant used in the test was changed as shown in Table 9. Table 9 shows the evaluation results in Examples 20 to 31 and Comparative Examples 8 and 9.

As shown in Table 9, in Examples 20 to 31 using the polymer flocculant of the present invention, coarse aggregated flocs were formed and the SS concentration of treated water was low. In particular, Examples 20-22, 25 in which the reduced viscosity of the amphoteric polymer (B) is in the range of 3.0 to 7.5 dL / g and A / C is in the range of 0.25 to 0.45. In ˜31, coarse coagulated flocs having a large diameter were obtained, and treated water with a low quality COD and a high quality water was obtained. Moreover, although Examples 25-31 are examples using the polymer flocculent which consists of a mixture containing a cationic polymer (C), the content rate of the cationic structural unit of a cationic polymer (C), and the mixing ratio of each polymer In Examples 25, 26, 29, and 30 in which the ratio is within the predetermined ratio range of the present invention, an excellent decolorization effect with a lower COD of the treated water was obtained.

Comparative Examples 8 and 9 are examples using a sludge dehydrating agent in which the mixing ratio of each polymer is outside the range of the predetermined ratio of the present invention. Both of the formed floc flocs are small and the SS concentration and COD of the treated water are high. It was.

(Example 32, Comparative Example 10)
[Use colored wastewater]
As the colored wastewater generated from the wastewater treatment facility for food, the wastewater having the following characteristics was used in the colored wastewater collected at the wastewater treatment facility of N Corporation. That is, a colored wastewater having a pH of 6.50, an SS concentration of 510 mg / L, an electric conductivity of 0.75 mS / cm, and a COD of 780 mg / L measured using an analysis method described in JIS standards. .

[Aggregation test]
The same aggregation test as in Example 1 was performed except that the polymer flocculant used in the test was changed as shown in Table 10. The evaluation results in Example 32 and Comparative Example 10 are shown in Table 10.

As shown in Table 10, in Example 32 using the polymer flocculant of the present invention, a coarse coagulation floc was formed, the SS concentration of the treated water was low, the COD of the treated water was low, and the quality treated water was of good quality. was gotten. Comparative Example 10 was an example using a sludge dehydrating agent in which the mixing ratio of each polymer deviated from the range of the predetermined ratio of the present invention. The formed flocs were small, and the SS concentration and COD of the treated water were high.

According to the present invention, even in a wastewater flocculation process, a good flocculation floc can be formed even if the amount of chemical used is small, the amount of sludge generated is reduced, and the chromaticity is greatly reduced, thus providing a good water quality treatment. It can be widely applied as an aggregating agent from which water is obtained.

Claims (10)

A coagulation flocculant is formed by adding a polymer flocculant to waste water to form a floc floc and then solid-liquid-separates the formed floc floc. The polymer flocculant is an amidine-based cationic polymer (A ) And the amphoteric polymer (B), and the mixing ratio of the polymer (A) and the amphoteric polymer (B) as a mass is 5: 5 to 8: 2. The flocculation treatment agent for wastewater according to claim 1, wherein the amidine-based cationic polymer (A) is a polymer having an amidine structural unit represented by either the following general formula (1) or the following general formula (2).


(In the general formulas (1) and (2), R ¹ and R ² each independently represent a hydrogen atom or a methyl group, and X ⁻ represents an anion.) The wastewater according to claim 1 or 2, wherein the amphoteric polymer (B) is a polymer having a cationic structural unit represented by the following general formula (3), an anionic structural unit, and a nonionic structural unit. Aggregation treatment agent.

(Wherein R ³ represents a hydrogen atom or a methyl group, R ⁴ and R ⁵ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ⁶ has 1 carbon atom) represents to 4 alkyl group or a benzyl group, Y represents an oxygen atom or NH, Z ^- represents an anion, n is an integer of 1 to 3). The coagulation treatment agent for wastewater according to any one of claims 1 to 3, wherein the 1 V sodium chloride aqueous solution of the amphoteric polymer (B) has a reduced viscosity at 25 ° C of 0.1 to 10 dL / g. When the ratio of the anionic structural unit of the amphoteric polymer (B) to all structural units is Ma mol% and the ratio of the cationic structural unit to all structural units is Mc mol%, the ratio Ma / Mc is 0.15 to 0.15. The flocculation treatment agent for wastewater according to any one of claims 1 to 4, which is 0.55. The polymer flocculant according to any one of claims 1 to 5, which contains a non-amidine cationic polymer (C) in addition to the amidine cationic polymer (A) and the amphoteric polymer (B). Waste water coagulant. The coagulation treatment of wastewater according to claim 6, wherein the non-amidine cationic polymer (C) is a non-amidine cationic polymer containing 60 to 100 mol% of a cationic monomer unit represented by the following general formula (4). Agent.

(Wherein R ³ represents a hydrogen atom or a methyl group, R ⁴ and R ⁵ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ⁶ has 1 carbon atom) represents to 4 alkyl group or a benzyl group, Y represents an oxygen atom or NH, Z ^- represents an anion, n is an integer of 1 to 3). Sum of the amidine cationic polymer (A) and the amphoteric polymer (B) in the total amount of the amidine cationic polymer (A), the amphoteric polymer (B) and the non-amidine cationic polymer (C). The waste water coagulation treatment agent according to any one of claims 6 to 7, wherein the ratio of the amount to the mass of the non-amidine cationic polymer (C) is 8: 2 to 5: 5. A coagulation treatment method for wastewater using the coagulation treatment agent according to any one of claims 1 to 8. The wastewater aggregation treatment method according to claim 9, wherein the wastewater is colored wastewater.