JP2006007208A - Method for treating waste water containing resin particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method, easy in operation and control at a low running cost, for treating waste water having high COD concentration containing a suspended resin particle, and a surface-active agent and/or a water soluble polymer of high concentration. <P>SOLUTION: The method for treating the waste water containing the resin particle (A) whose volume average particle diameter is 0.0005 to 500 μm and the surface-active agent (B) and/or the water soluble polymer (C) comprises a process of adding an inorganic coagulant (a) to the waste water, a process of adding a highmolecular coagulant (b) thereto, and, if necessary, a process of adding an organic coagulant (c) thereto. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for treating wastewater containing resin particles.

Conventionally, as a method for producing resin particles, a monomer solution or a monomer solution dissolved in a solvent if necessary is dispersed in an aqueous medium in the presence of a dispersing agent (auxiliary) such as a surfactant or a water-soluble polymer, and then polymerized. Method (emulsion polymerization method or suspension polymerization method), a resin solution previously dissolved in a resin or, if necessary, a solvent, is dispersed in an aqueous medium in the presence of a dispersing (auxiliary) agent such as a surfactant or a water-soluble polymer, A method of removing the solvent by heating or reducing the pressure as necessary to obtain resin particles (dissolved resin suspension method) is known. In the production of these resin particles, a large amount of surfactant and / or water-soluble polymer is used for the purpose of reducing the particle size of the obtained particles or making the particle size more uniform. There are problems such as high concentration of chemical oxygen demand (hereinafter referred to as COD) and a large amount of suspended solids such as resin particles in the wastewater. Is required.
Examples of methods for treating waste water containing a large amount of these surfactants and / or water-soluble polymers include evaporation concentration method, activated carbon adsorption method (Patent Document 1), activated sludge method (Patent Documents 2 and 3), and ultraviolet decomposition method. (Patent Document 4). Among these, the evaporation concentration method is a method in which the wastewater is heated to boiling and the water in the wastewater is evaporated to reduce the volume of the wastewater. The activated carbon adsorption method adsorbs organic matter in the wastewater by activated carbon. It is a method of removing. The activated sludge method is a method of decomposing organic matter in wastewater by microorganisms in activated sludge by introducing wastewater into an aeration tank containing activated sludge and aeration. Further, the ultraviolet decomposition method is a method of decomposing organic matter in wastewater with light energy by irradiating the wastewater with a photocatalyst and ultraviolet rays.
Moreover, as a method for treating wastewater containing resin particles, there is a method of removing the resin particles from wastewater by filtration in advance (Patent Document 5).

Japanese Patent Application Laid-Open No. 7-222973 JP 2000-140884 A JP 2000-354891 A JP 2002-346577 A JP-A-8-269127

However, when treating wastewater containing a large amount of resin particles and a surfactant and / or water-soluble polymer, bubbles are generated during the evaporation and concentration because the above-mentioned evaporation and concentration method contains a large amount of surfactant. However, it becomes difficult to concentrate, and a large amount of energy costs are required for incineration of the residue after heating and after concentration, and the activated carbon adsorption method uses an enormous amount of activated carbon for wastewater. Activated carbon itself becomes a secondary waste, and in order to remove resin particles, another treatment method (for example, the method of the above-mentioned Patent Document 5) must be used in combination, and a great deal of treatment cost and treatment time are required. In the activated sludge method, long-term aeration is required to reduce the COD concentration to the desired level, problems such as difficulty in operation management such as organic matter concentration in wastewater, ultraviolet rays The solution, when such resin particles is cloudy exists and wastewater there is a problem not fully effective. In particular, the treatment becomes more difficult as the resin particles become finer, and there is a problem that costs and time are required.
For this reason, there has been no effective treatment method to date for the treatment of wastewater containing a large amount of resin particles and a surfactant and / or a water-soluble polymer, which are the subject of the present invention.

  Accordingly, the object of the present invention is to reduce the low-running COD components and suspended particles in wastewater containing resin particles and high concentrations of surfactants and / or water-soluble polymers discharged during the production of resin particles. An object of the present invention is to provide a treatment method that can be removed at once by cost, short time, and simple operation management, and that can satisfy wastewater treatment regulations.

  As a result of intensive studies on the above-mentioned wastewater treatment method, the present inventors have found that the above problems can be solved by adding the inorganic flocculant (a) and the polymer flocculant (b) to the wastewater, respectively. Reached.

  That is, the present invention relates to a method for treating a wastewater containing resin particles (A) having a volume average particle diameter of 0.0005 to 500 μm and a surfactant (B) and / or a water-soluble polymer (C). A method for treating wastewater, comprising a step of adding an agent (a), a step of adding a polymer flocculant (b), and a step of adding an organic coagulant (c) if necessary.

  The treatment method of the present invention has an effect that COD components in wastewater can be efficiently removed by low running cost and simple operation management. In addition, since the resulting floc is dense and strong, there is no increase in the suspension concentration in the filtrate during the subsequent solid-liquid separation process, reducing the moisture content of the dehydrated cake after solid-liquid separation, and reducing the amount of waste generated The effect of making it possible.

  The resin particles (A) are not particularly limited, and for example, vinyl resins, polyurethane resins, epoxy resins, polyester resins, polyamide resins, polyimide resins, silicon resins, phenol resins, melamine resins, urea resins, aniline resins, ionomer resins, Known resins such as polycarbonate resin can be used. As (A), two or more of the above resins may be mixed.

The volume average particle diameter (μm) of (A) is 0.0005 to 500. From the viewpoint of the removability of the COD component and the ease of the aggregation reaction with the polymer flocculant (b), it is preferably 0.01 to 300, particularly preferably 0.05 to 50. When the volume average particle diameter (μm) is less than 0.0005, the suspension concentration in the filtrate increases, and when it exceeds 500, the floc strength decreases.
The volume average particle diameter can be measured with a laser type particle size distribution analyzer LA-920 (manufactured by Horiba, Ltd.) or Multitizer III (manufactured by Coulter, Inc.).
The shape of (A) is not particularly limited, and examples thereof include an indefinite shape such as a crushed shape, a spherical shape such as a true spherical shape, an elliptical shape, and a kitchen shape.

The surfactant (B) includes known ones such as an anionic surfactant (B1), a cationic surfactant (B2), an amphoteric surfactant (B3), and a nonionic surfactant (B4). Examples thereof include those described in Japanese Patent Application Laid-Open No. 2002-284881. These surfactants (B) may be a mixture of two or more.
Of these, (B1), (B2) and (B3) are preferable from the viewpoint of the effect of removing the COD component, (B1) and (B3) are more preferable, and (B1) is particularly preferable. Most preferred are sulfonate surfactants among (B1).
Specific examples of the sulfonate surfactant include alkylbenzene sulfonate (for example, sodium dodecylbenzene sulfonate), alkyl naphthalene sulfonate (for example, sodium dodecyl naphthalene sulfonate), sulfosuccinic acid diester type (for example, Sulfosuccinic acid di-2-ethylhexyl ester sodium salt), α-olefin sulfonates, Igepon T type, sulfonates of other aromatic ring-containing compounds (eg mono- or disulfonates of alkylated diphenyl ethers, styrenated phenol sulfonates) Salt).

The water-soluble polymer (C) is a known dispersant having a weight average molecular weight of 5,000 to 200,000, and examples include those other than the polymer flocculant (b) and the organic coagulant (c) described later. .
For example, cellulosic compounds (eg, methylcellulose, ethylcellulose, hydroxyethylcellulose, ethylhydroxyethylcellulose, carboxymethylcellulose, hydroxypropylcellulose and saponified products thereof), gelatin, starch, dextrin, gum arabic, chitin, chitosan, polyvinyl alcohol, polyvinylpyrrolidone , Polyethylene glycol, polyethyleneimine, polycarboxylate [for example, sodium poly (meth) acrylate, sodium acrylate-acrylic acid ester copolymer, sodium hydroxide (partial) neutralization of styrene-maleic anhydride copolymer Product], water-soluble polyurethane (for example, reaction product of polyethylene glycol, polycaprolactone diol, etc. and polyisocyanate) And the like. Of these, cellulose compounds and polycarboxylates are preferable from the viewpoint of wastewater treatment efficiency, and carboxymethyl cellulose and sodium poly (meth) acrylate are particularly preferable. Further, (C) may be a mixture of two or more.

  The content (% by weight) of (A), (B) + (C) contained in the wastewater is not particularly limited, but usually (A) is 0.0001-20, (B) + (C) Is 0.001-30, and (A) is preferably 0.001 from the point that a better agglomeration state (dense and strong floc, low moisture content of dehydrated cake after solid-liquid separation) can be realized. 5, particularly preferably 0.01 to 1, and (B) + (C) is preferably 0.01 to 10, particularly preferably 0.1 to 5. Further, (B) / (C) (weight ratio) is preferably 95/5 to 5/95, and particularly preferably 80/20 to 20/80, from the same viewpoint.

  The waste water targeted by the treatment method of the present invention comprises resin particles (A) having a volume average particle diameter (μm) of 0.0005 to 500, a surfactant (B) and / or a water-soluble polymer (C). Although it will not specifically limit if it is the wastewater to contain, The wastewater discharged | emitted especially in the case of manufacture of a resin particle (A) is suitable from a viewpoint of wastewater treatment efficiency.

  The waste water containing the resin particles (A) suitable for the treatment method of the present invention includes a water dispersion step (I) in which monomers and / or resins are dispersed in water and polymerized as necessary, and the resin particles are solid-liquid separated. Waste water discharged from the production process of the resin particles (A) comprising the step (II) and, if necessary, the step (III) for further washing the resin particles.

As a method for dispersing the resin particles in water in the water dispersion step (I), for example, using a monomer as a starting material, a polymerization reaction such as a suspension polymerization method, an emulsion polymerization method, a seed polymerization method or a dispersion polymerization method can be performed directly in water. A method for producing resin particles (a), a method for producing resin particles by pulverizing a resin produced by a polymerization reaction using a wet pulverizer (for example, a ball mill, a Gaurin homogenizer), and making the particles fine in water (I) ), A resin solution in which a resin is previously dissolved in a solvent is dispersed in an aqueous medium in the presence of a dispersing agent (auxiliary) such as a surfactant (B) and / or a water-soluble polymer (C), and this is heated or reduced in pressure. The method of removing a solvent by the above and obtaining resin particles (dissolved resin suspension method) (c) is mentioned.
Of the wastewater discharged from the manufacturing process by these methods, the wastewater suitable for the treatment method of the present invention is wastewater discharged from the manufacturing process by the methods (a) and (c). In particular, in (c), waste water discharged from the production process of the resin particles (A) by the method (c-1) of forming resin particles in an aqueous dispersion of the resin fine particles (A1) and / or inorganic fine particles (D). It is.
Specific examples of the method (c-1) include the methods described in JP-A No. 2002-284881 and JP-A No. 9-319144.

In (C-1), examples of (A1) include those having the same composition as the resin particles (A) described above. (D) is not particularly limited, and examples thereof include silica, alumina, titania, calcium carbonate, magnesium carbonate, tricalcium phosphate, clay, diatomaceous earth, and bentonite, and the particle surface has a carboxyl group. It may be coated with a polymer.
The volume average particle diameters of (A1) and (D) are not particularly limited, but are preferably 0.0005 to 100 μm, particularly preferably 0.05 to 5 μm from the viewpoint that the suspension concentration in the treated water can be lowered. It is.

  Moreover, the wastewater which is the target of the treatment method of the present invention may contain (A1) and / or (D). When (A1) and / or (D) is included, the content (% by weight) of (A) including (A1) in the wastewater is the same as the preferred content of (A) above, The content (% by weight) is preferably 0.0001 to 10, particularly preferably 0.001 to 1.

  As the wastewater discharged in this production process, those discharged in the solid-liquid separation step (II) and the washing step (III) are particularly preferable from the viewpoint of wastewater treatment efficiency. Further, the treatment method of the present invention can treat these wastewaters without any problems even if they are treated alone or mixed with other factory wastewaters. For this reason, the treatment method of the present invention can process a variety of products in the middle of production or after washing, etc. in a single place in a factory that produces a wide variety of products. There are advantages such as being able to minimize.

  As the waste water discharged from the step (II), for example, an aqueous dispersion composed of the resin particles (A) obtained in the step (I) and the resin fine particles (A1) and / or inorganic fine particles (D), Examples include waste water such as separation water generated when solid-liquid separation is performed using a solid-liquid separation device (for example, a centrifugal separator, a spatula filter, a filter press, and a belt filter).

  As the waste water discharged from the step (III), for example, after the solid-liquid separation in (II), the separated (A) and (A1) and / or (D) are washed water (for example, tap water, industrial Water (distilled water, ion-exchanged water) is used, and waste water generated when the surface deposits (A) (for example, (B), (C), (A1), and (D)) are washed. . As a washing method, the washing water is added to the slurry after the solid-liquid separation in (II) and the solid-liquid separation is performed again by the above method, and through-washing is performed on a filter such as a spatula filter, a filter press, and a belt filter. A method is mentioned.

  Moreover, the waste water used for this invention may contain other components (E) other than said (A), (B), (C), (A1), and (D). Examples of (E) include pigments, fillers, antistatic agents, colorants, mold release agents, charge control agents, ultraviolet absorbers, antioxidants, antiblocking agents, heat stabilizers, and flame retardants.

The pH of the wastewater is not particularly limited, but is preferably 3 to 10, more preferably 4 to 9. When the pH is in this range, the effect of the present invention is more easily exhibited.
Moreover, when it remove | deviates from the said pH range, you may adjust with a pH adjuster. Examples of the pH adjuster include mineral acids such as sulfuric acid, hydrochloric acid and phosphoric acid, and alkaline substances such as sodium hydroxide, potassium hydroxide and slaked lime.

Examples of the inorganic flocculant (a) used in the wastewater treatment method of the present invention include sulfate band, aluminum chloride, ammonium alum, potassium alum, polyaluminum chloride, polyaluminum sulfate, ferrous sulfate, ferric sulfate, and chloride chloride. Examples thereof include ferric iron, copper chloride, polyferric sulfate, polyferric chloride, slaked lime, magnesium oxide, and magnesium carbonate.
Among these, from the point that the addition amount can be reduced, preferred is a sulfate band, ferric chloride, polyaluminum chloride, polyaluminum sulfate, polyferric chloride, ferric sulfate, slaked lime, and more preferred. Ferric chloride, polyaluminum chloride, polyaluminum sulfate, polyferric chloride, polyferric sulfate, particularly preferred is ferric chloride, polyaluminum chloride, polyferric sulfate, most preferred is ferric chloride It is ferric and polyaluminum chloride.
The inorganic coagulants may be used alone or in combination of two or more.

The polymer flocculant (b) used in the wastewater treatment method of the present invention has an intrinsic viscosity (dl / dl) measured at 30 ° C. in a 1N—NaNO ₃ aqueous solution from the viewpoint of a good flocculation state and the amount of addition can be reduced. g) is preferably 5 to 40, more preferably 10 to 30, particularly preferably 12 to 25.
Examples of (b) include anionic polymer flocculants (b1), cationic polymer flocculants (b2), amphoteric polymer flocculants (b3) and nonionic polymer flocculants (b4). These may be used alone or as a mixture of two or more.
Here, the anionic polymer flocculant is a polymer flocculant having an anionic group in the molecule, that is, a polymer flocculant exhibiting anionic property when dissolved in water, Is a polymer flocculant having a cationic group in the molecule, that is, a polymer flocculant exhibiting a cationic property when dissolved in water, and an amphoteric polymer flocculant is a cationic group and an anion in the molecule. It is a polymer flocculant having an ionic group, that is, a polymer flocculant exhibiting a cationic property and an anionic property when dissolved in water.

  Examples of the anionic polymer flocculant (b1) include poly (meth) acrylate, (meth) acrylamide / (meth) acrylate copolymer, (meth) acrylamide / 2- (meth) acryloylamino- 2-methylpropanesulfonate copolymer, (meth) acrylamide / (meth) acrylate / 2- (meth) acryloylamino-2-methylpropanesulfonate copolymer, (meth) acrylamide / 2- ( (Meth) acryloyloxyethane sulfonate copolymer, (meth) acrylamide / (meth) acrylate / 2- (meth) acryloyloxyethane sulfonate copolymer, (meth) acrylamide / 2- (meth) acryloyl Oxypropane sulfonate copolymer, (meth) acrylamide / (meth) acrylate / 2- (me ) Acryloyloxypropane sulfonate copolymer, (meth) acrylamide / (meth) acrylate / 2- (meth) acryloylamino-2-methylpropane sulfonate / 2- (meth) acryloyloxyethane sulfonate / 2- (meth) acryloyloxypropane sulfonate copolymer and the like. Examples of the salt in the above include alkali metal (lithium, sodium, potassium, etc.) salts and alkaline earth metal (magnesium, calcium, etc.) salts. Two or more of these salts may be mixed.

  Examples of the cationic polymer flocculant (b2) include aminoalkyl [carbon number (hereinafter abbreviated as C) 1-4] (meth) acrylate (co) polymer [for example, poly N, N-dimethylaminoethyl. (Meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate / (meth) acrylamide copolymer], aminoalkyl (C1-4) (meth) acrylamide (co) polymer [for example, poly N, N- Dimethylaminomethyl (meth) acrylamide, N, N-dimethylaminomethyl (meth) acrylamide / (meth) acrylamide copolymer], polyamidine (for example, those obtained by the method described in JP-A No. 05-192513) , Chitosan, and salts thereof [eg, hydrochloride, hydrobromide, hydroiodide, sulfate, sulfite , Phosphate, nitrate, acetate, methyl chloride salt, dimethyl sulfate and benzyl chloride salt] can be mentioned.

As the amphoteric polymer flocculant (b3), for example, a copolymer comprising (meth) acrylamide, (meth) acrylic acid (salt) and aminoalkyl (C1-4) (meth) acrylate salt [for example, (meth) Acrylamide / (meth) acrylic acid (salt) / N, N-dimethylaminoethyl (meth) acrylate / methyl chloride quaternary copolymer, (meth) acrylamide / (meth) acrylic acid (salt) / N, N- Dimethylaminoethyl acrylate / methyl chloride quaternized compound / N, N-dimethylaminoethyl methacrylate / methyl chloride quaternized copolymer]. Examples of the (meth) acrylic acid salt and aminoalkyl (C1-4) (meth) acrylate salt include those exemplified in the above (b1).
Examples of the nonionic polymer flocculant (b4) include materials other than the water-soluble polymer (C), such as polyacrylamide.

  Of these, (b1), (b2) and (b3) are preferable because a better aggregation state can be realized, and (meth) acrylamide / (meth) acrylic in (b1) is more preferable. Acid salt copolymer, (meth) acrylamide / 2- (meth) acryloylamino-2-methylpropanesulfonate copolymer, (meth) acrylamide / sodium (meth) acrylate / 2- (meth) acryloylamino- 2-methylpropanesulfonate copolymer, N, N-dimethylaminoethyl (meth) acrylate / methyl chloride quaternized / (meth) acrylamide copolymer in (b2), N, N-dimethylaminoethyl (Meth) acrylate hydrochloride / (meth) acrylamide copolymer, and (meth) acrylamide / (meta) in (b3) Acrylic acid (salt) / N, N-dimethylaminoethyl (meth) acrylate / methyl chloride quaternized copolymer, (meth) acrylamide / (meth) acrylic acid (salt) / N, N-dimethylaminoethyl acrylate / Methyl chloride quaternized / N, N-dimethylaminoethyl methacrylate / methyl chloride quaternized copolymer, (meth) acrylamide / (meth) acrylate copolymer, (meth) acrylamide / ( (Meth) sodium acrylate / 2- (meth) acryloylamino-2-methylpropanesulfonate copolymer, N, N-dimethylaminoethyl (meth) acrylate / methyl chloride quaternized / (meth) acrylamide copolymer , (Meth) acrylamide / (meth) acrylic acid (salt) / N, N-di Tyraminoethyl (meth) acrylate / methyl chloride quaternized copolymer, and (meth) acrylamide / (meth) acrylic acid (salt) / N, N-dimethylaminoethyl acrylate / methyl chloride quaternized / N, N -A dimethylaminoethyl methacrylate / methyl chloride quaternized copolymer.

  The polymer flocculant (b) is preferably used in combination with (b1) and (b3) or (b2) and (b3) from the viewpoint of flock strength. As a method of using (b1) and (b3) or (b2) and (b3) in combination, a method of adding (1) (b1)-(b3) or (b2)-(b3) in this order, 2) Method of adding (b3)-(b1) or (b3)-(b2) in this order, (3) Method of adding (b1), (b3), or (b2), (b3) simultaneously And (4) Any of the methods of adding the mixture after (b1) / (b3) or (b2) / (b3) in advance may be used. Among these, the method (1) is preferable from the viewpoint of floc strength. In the method (1), it is preferable to add (b3) after adding (b1) or (b2) to the wastewater with sufficient mixing and stirring from the viewpoint of floc strength.

  Among the polymer flocculants (b) used in the present invention, the colloid equivalent value (meq / g) described below is preferably in the following range from the viewpoint that a better aggregation state can be realized. The anion colloid equivalent value of (b1) is preferably −9 to −0.7, more preferably −6 to −1.5, and particularly preferably −6 to −2. The cation colloid equivalent of (b2) is preferably 0.1 to 9, more preferably 0.5 to 7, and particularly preferably 1 to 5. The cation colloid equivalent of (b3) is 0.1 to 9, more preferably 0.5 to 7, particularly preferably 1 to 5, and the anion colloid equivalent value is preferably -9 to -0.7, more preferably. It is −6 to −1.5, particularly preferably −6 to −2.

In the wastewater treatment method of the present invention, a stronger and denser floc can be formed by further adding the organic coagulant (c) to the wastewater.
(C) has an intrinsic viscosity (dl / g) of 0.1 to 3 measured at 30 ° C. in a 1N—NaNO ₃ aqueous solution, and is preferable from the viewpoint of neutralizing the surface charge of the suspended particles. Is ionic (anionic and / or cationic) in water.
Examples of (c) include an anionic organic coagulant (c1), a cationic organic coagulant (c2), and an amphoteric organic coagulant (c3). These may be used alone or as a mixture of two or more.
Here, the anionic organic coagulant is an organic coagulant having an anionic group in the molecule, that is, an organic coagulant exhibiting anionic property when dissolved in water. Is an organic coagulant having a cationic group in the molecule, that is, an organic coagulant having a cationic group when dissolved in water, and an amphoteric organic coagulant having a cationic group and an anionic group in the molecule. That is, it is an organic coagulant that exhibits cationic and anionic properties when dissolved in water.
As (c1), for example,
(C1-1): Polysulfonic acid organic coagulant [for example, polystyrenesulfonic acid (salt), naphthalenesulfonic acid (salt) / formalin polycondensate, alkyl (C1-6) naphthalenesulfonic acid (salt) / formalin polycondensation object],
(C1-2): Other polyanionic organic coagulant [for example, the same composition as that exemplified in the above-mentioned anionic polymer flocculant (b1) and an intrinsic property measured at 30 ° C. in a 1N—NaNO ₃ aqueous solution Viscosity (dl / g) of 0.1-3]
Etc.

(C2) includes the following and salts thereof [for example, hydrochloride, hydrobromide, hydroiodide, sulfate, sulfite, phosphate, nitrate, acetate, methyl chloride salt , Dimethyl sulfate and benzyl chloride salts].
(C2-1): Dicyan-based organic coagulant [for example, dicyandiamide / formalin polycondensate, dicyandiamide / dialkylene (C1-4) polyamine polycondensate],
(C2-2): allylamine organic coagulating agent [e.g., (di) allyl amine (salt) polymer (poly dimethyl diallyl ammonium chloride and the like), diallylamine (salt) · SO ₂ copolymer, dialkyl (C1 -4) allylamine (Salt) polymer, dialkyl (C1-4) allylamine (salt) / SO ₂ copolymer, alkyl (C1-4) diallylamine (salt) polymer, alkyl (C1-4) diallylamine (salt) / SO ₂ copolymer Polymer]],
(C2-3): polyalkylene (C1-6) polyamine organic coagulant [for example, polyethyleneimine (salt), tetraethylenepentamine (salt), ethylene dichloride / ammonia condensate, propylene dichloride / ammonia condensate, ethylene Dichloride / dimethylamine condensate, propylene dichloride / dibutylamine condensate, ethylene dichloride / aniline condensate, epichlorohydrin / ammonia condensate, epichlorohydrin / dialkyl (C1-4) amine condensate, epichlorohydrin / diphenylamine condensate, tetrahydrofurfuryl chloride -Dialkyl (C1-4) amine condensate, allylamine addition polymer]
(C2-4): Other polycationic organic coagulant [for example, aniline-formalin polycondensate hydrochloride, polyvinylbenzyldimethylammonium chloride, polyvinylimidazoline (salt), the above-described cationic polymer flocculant (b2) A composition similar to that exemplified, and having an intrinsic viscosity (dl / g) of 0.1 to 3 measured at 30 ° C. in a 1N—NaNO ₃ aqueous solution];
Etc.

Examples of (c3) include (meth) allylamine or di (meth) allylamine / maleic acid copolymer, (meth) allylamine or di (meth) allylamine / citraconic acid copolymer, (meth) allylamine or di (meth) ) Allylamine / itaconic acid, (meth) allylamine or di (meth) allylamine / fumaric acid copolymer, composition similar to that exemplified for the amphoteric polymer flocculant (b3) described above, and in a 1N-NaNO ₃ aqueous solution The thing with an intrinsic viscosity (dl / g) measured at 30 degreeC of 0.1-3 is mentioned.

Of these, (c2) and (c3) are preferred, (c2) is more preferred, and (c2-1), (c2-2) and (C2-3) and most preferred are (c2-1) and (c2-3).
Moreover, the cation colloid equivalent value (meq / g) described later of the organic coagulant (c) is preferably 3 to 20, more preferably 4.5 to 12.5, from the viewpoint that a better aggregation state can be realized. Especially preferably, it is 5-12.

The colloid equivalent values of (b) and (c) can be determined by the colloid titration method shown below. The following measurement is performed at room temperature (20 ° C.).
(1) Preparation of measurement sample (50 ppm aqueous solution) 0.200 g of sample (converted to solid content) is precisely weighed and taken in a 200 ml beaker, and the total weight (total weight of sample and ion-exchanged water) is 100.0 g. After adding ion-exchanged water so as to become, a magnetic stirrer (1,000 rpm) is stirred and completely dissolved (for example, 3 hours) to prepare a 0.2 wt% water-soluble polymer solution. Further, take 10 ml of the solution prepared above in a 500 ml glass beaker using a 10 ml hole pipette, and add ion exchange water so that the total weight (total weight of the solution and ion exchange water) is 400.0 g. The sample is again stirred with a magnetic stirrer (1,000 to 1,200 rpm) for 30 minutes to obtain a uniform measurement sample.
The solid content of the polymer flocculant (b) or the organic coagulant (c) was determined by weighing about 1.0 g of the sample in a petri dish (x), and in a circulating dryer at 105 ± 5 ° C. for 90 minutes. This is a value calculated from the following equation, where (y) is the residual weight after drying.

Solid content (% by weight) = (y) × 100 / (x)

(2) Measurement of cation colloid equivalent value 100 g of the above measurement sample is placed in a 200 ml glass conical beaker, and a 0.5 wt% aqueous sulfuric acid solution is gradually added while stirring to adjust the pH to 3. Next, add 2-3 drops of toluidine blue indicator (TB indicator) and titrate with N / 400 potassium potassium sulfate (N / 400 PVSK) reagent. The titration rate is 2 ml / min, and the end point is the time when the measurement sample changes from blue to magenta and is held for 30 seconds.
(3) Measurement of anion colloid equivalent value 100 g of the above measurement sample was put in a 200 ml glass conical beaker, and 0.5 ml of an N / 10 sodium hydroxide aqueous solution was added while stirring with a magnetic stirrer (500 rpm). After adding 5 ml of a methyl glycol chitosan aqueous solution using a 5 ml whole pipette, the mixture is stirred for 5 minutes (pH at that time is about 10.5). Add 2-3 drops of TB indicator and titrate as in (2).
(4) Blank test The same operation as (2) and (3) is performed except that 100 g of ion-exchanged water is used instead of the measurement sample.
(5) Calculation method

Cation or anion colloid equivalent value (meq / g)
= 1/2 × (sample titration—blank test titration) × (N / 400 PVSK titer)

In the above test method, when the molecular weight of (b) is relatively high, for example, when the intrinsic viscosity [η] (dl / g) at 30 ° C. is 5 or more in a 1N-NaNO ₃ aqueous solution, a more accurate value is obtained. In order to guide, it is preferable to adopt the molecular cleavage method described below.
According to the molecular cleavage method, a 0.2% by weight water-soluble polymer solution was prepared according to the above-mentioned method, and 50.0 g of the resulting solution was placed in a 150 ml plastic disposable cup and homogenizer [for example, Nippon Seiki ( This is a method of reducing viscosity by stirring at 4000 rpm for 5 minutes. At this time, it is preferable that the stirring blade is as close to the bottom surface as possible because stirring can be performed more uniformly.

In the present invention, the addition amount (% by weight) of (a), (b) and (c) is appropriately adjusted according to the concentrations of (A) and (B) and / or (C) in the wastewater. From the viewpoint of good aggregation state and COD component removal, preferably (a) is 0.0005 to 20, (b) is 0.00001 to 0.5, and (c) is 0 to 0 with respect to waste water. 1, more preferably (a) is 0.001 to 10, (b) is 0.0001 to 0.1, (c) is 0.0001 to 0.5, particularly preferably (a) is 0.01 to 5, (b) is 0.0005 to 0.05, and (c) is 0.0005 to 0.1.
When (c) is used, from the same viewpoint, the weight ratio [(b) / (c)] of (b) and (c) is preferably 90/10 to 10/90, more preferably 70 / 30 to 12/88, particularly preferably 50/50 to 20/80.

  The form of (a), (b) and (c) may be any known form such as powder, film, aqueous solution, w / o emulsion, suspension, etc. (A) is powder, aqueous solution or suspension, (b) is powder, aqueous, w / o emulsion or suspension, (c) is powder, aqueous or w / o emulsion. is there.

The treatment method of waste water containing resin particles (A) having a volume average particle diameter of 0.0005 to 500 μm and a surfactant (B) and / or a water-soluble polymer (C) according to the present invention is an inorganic flocculant. The step of adding (a) and the step of adding the polymer flocculant (b) are included. The order of the steps of adding (a) and (b) may be (a)-(b), (b)-(a), or (a), (b) at the same time. However, (a) to (b) are preferable from the viewpoint of a good aggregation state and COD component removal. In this step, from the viewpoint of efficient removal of COD components, it is preferable to add (a) to the wastewater, then adjust the pH of the wastewater, and further add (b).
The wastewater treatment method of the present invention preferably includes a step of adding an organic coagulant (c) in addition to the steps of adding (a) and (b) from the viewpoint of efficient removal of COD components.
The order of the addition steps (a), (b) and (c) is not particularly limited, but from the viewpoint of a good aggregation state and COD component removal, (a) and (c) are added, and ( It is preferable to add b). (A) and (c) may be added separately or at the same time. In this step, it is preferable to add (a) and (c) to the wastewater from the viewpoint of efficient removal of COD components, adjust the pH of the wastewater after sufficiently stirring, and then add (b).
The state of the wastewater at this time will be specifically described. First, (a) and, if necessary, (c) are added to the wastewater and stirred, so that the dissolved or dispersed COD components [mainly (B) and (C )] Reacts with these to precipitate. These precipitates and suspended particles in waste water [containing resin particles (A) and (A1) and / or (D)] are aggregated by adding (b) and stirring, It is possible to form strong and dense flocs (lumps) that are characteristic.
The pH of the waste water to be adjusted after adding (a) to the waste water or after adding (a) and (c) is preferably 5 to 8 from the viewpoint of good aggregation state and COD component removal. Preferably it is 6-7. Examples of the pH adjusting agent used for adjusting to the above pH include those described above.
Further, the temperature (° C.) at the time of the wastewater treatment of the present invention is not particularly limited, but is preferably from 5 to 90, more preferably from 10 to 70, particularly preferably from the viewpoint of the aggregation state and effective COD component removal. 15-50.

The method for adding (a), (b) and, if necessary, (c) to the wastewater is not particularly limited. For example, a known method [for example, “Introduction to Polymer Drugs” issued by Sanyo Chemical Industries, Ltd., p. 416 method] can be used.
(A), (b) [and (c) if necessary] are preferably used after being diluted with water, such as an aqueous solution or a water suspension, and added to the waste water. Good. The concentration (% by weight) when (a), (b) and, if necessary, (c) diluted with water is preferably from 1 to 50, from the viewpoint of solubility and handling, (b) ) Is 0.05 to 1, and (c) is 0 to 50.
The dilution method is not particularly limited, but when (a), (b) or (c) is solid, for example, a predetermined amount of (a), (b) or ( A method of adding c) and stirring can be employed. In particular, when powdered (b) is dissolved in water, adding (b) at a time causes undesired formation, and (b) is not preferable because it is difficult to completely dissolve in water. The time required for dilution is usually about 1 minute to 1 hour in the case of (a) and (c), and about 2 to 8 hours in the case of (b).

  As the dehydration method (solid-liquid separation method) of floc obtained by the treatment method of the present invention, known centrifugal dehydration, belt press dehydration, filter press dehydration, capillary dehydration and the like can be applied, but centrifugal dehydration, belt press dehydration, Filter press dehydration can be used more suitably. Moreover, before dehydrating with these dehydrators, sedimentation and concentration may be performed in advance using a thickener or the like.

  Examples of the waste water to be treated in the present invention include slush molding resins, powder coatings, spacers for manufacturing electronic parts such as liquid crystal displays, standard particles for electronic measuring instruments, electrophotography, electrostatic recording, electrostatic printing Wastewater discharged at the time of use or production of resin particles useful for toners, hot melt adhesives, and other molding materials, etc. are preferred from the viewpoint of wastewater treatment efficiency. Wastewater.

[Example]
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to this. In the following description, “parts” represents parts by weight and “%” represents% by weight. The measuring method of the following item in the below-mentioned Tables 1-4 is as follows.
(1) Intrinsic viscosity [η] (dl / g)
Measured at 30 ° C. in 1N—NaNO ₃ aqueous solution.
(2) Colloid equivalent Measured by the colloid titration method.
(3) COD value Measured according to the COD _Mn analysis method described in JIS K-0102 (1998 edition).
(4) Moisture content of dehydrated cake Measured according to the analysis method described in the sewer test method (Japan Sewer Association, 1984 version).
(5) Flock particle size Jar tester [Miyamoto Riken Kogyo Co., Ltd., model JMD-6HS-A, and so on. ] Two plate-shaped stirring blades made of polyvinyl chloride (diameter 5 cm, height 2 cm, thickness 0.2 cm) were attached to the stirring bar continuously in a vertical shape so as to form a cross, and 200 ml of sludge was taken in a 300 ml beaker, Set it on the jar tester. Add the aqueous solution of (A), (B) or (C) with the specified concentration by the specified method while stirring the wastewater slowly at 120 rpm, stirring the wastewater, and after stirring for 30 seconds, stop stirring The size of the aggregate is visually observed (the floc particle size at a rotation speed of 120 rpm is shown in the table).
Subsequently, the rotational speed is set to 300 rpm, and after stirring for 30 seconds, the stirring is stopped and the size of the aggregate is visually observed again (the floc particle size at the rotational speed of 300 rpm is shown in the table).

Example 1
Mixed wastewater consisting of wastewater discharged in the solid-liquid separation step during the resin particle production process and wastewater discharged in the washing step (wastewater 1) [composition of main components in wastewater (A): polyester resin (volume average Particle size 8 μm), (B): sulfonic acid surfactant, (C): carboxymethyl cellulose, (A1): styrene / methacrylic acid resin (volume average particle size 0.2 μm), content of each component in waste water (A): 0.05%, (B): 1.5%, (C): 1.2%, (A1): 0.1%, pH is 7, COD value is 14,000 ppm, and so on . 200 parts were weighed into a 500 ml beaker. Jar tester [Miyamoto Riken Kogyo Co., Ltd., Model JMD-6HS-A] and two plate-like PVC stirring blades (diameter 5 cm, height 2 cm, thickness 0.2 cm) are continuously connected to form a cross. The beaker containing the waste water (waste water 1) was set on a jar tester. 10% polyaluminum chloride aqueous solution (a-1) [trade name “PAC250A” manufactured by Taki Chemical Co., Ltd. ] 10 parts (0.5% solid content / waste water) was added (pH 4 after addition). After stirring for a sufficient time (about 3 minutes), the pH was adjusted to 7 using a 48% aqueous solution of sodium hydroxide. Next, polymer flocculant (b-1) [manufactured by Sanyo Kasei Kogyo Co., Ltd., trade name “Sanflock AH-400P”, [η] 25 (dl / g), anion colloid equivalent −5.3 meq / g ,same as below. After adding 2 parts of 0.2% aqueous solution (0.002% solid content / waste water) and stirring, agglomerated flocs were formed and the floc particle size was measured by the method described above.
Subsequently, a stainless steel JIS standard [JIS Z8801-1 (2000)] wire mesh (22 mesh, mesh opening 710 μm, circular shape, diameter 9 cm), Nutsze funnel, 300 ml graduated cylinder was set, and the treated wastewater was filtered. A part of the filtered floc (about 5 g) was taken out with a spatula, sandwiched between two wire meshes as described above, and dehydrated using a press filter tester (1 kg / cm ² , 60 seconds). In addition, the dehydrated cake was obtained, and the turbidity of the treated water was visually determined with the following score.
<Turbidity of treated water>

○: Transparent (no suspended particles)
Δ: Slightly suspended particles x: Suspended particles are large

Table 1 shows the results of the COD value in the treated water, the water content of the dehydrated cake, the floc particle size, and the turbidity of the treated water.

Example 2
In place of 2 parts of 0.2% aqueous solution of (b-1), cationic polymer flocculant (b-2) [manufactured by Sanyo Chemical Industries, Ltd., trade name “Sanfloc CH-959P”, [η] 13.5 (dl / g), cation colloid equivalent 0.4 meq / g] 0.2% aqueous solution 2 parts (solid content added 0.002%) / waste water) The processing of the present invention was performed. The results are shown in Table 1.

Example 2 '
Instead of 2 parts of 0.2% aqueous solution of (b-1), 2 parts of (b-2) 0.2% aqueous solution (addition of solid content 0.002% / waste water) was added and stirred. Molecular flocculant (b-3) [manufactured by Sanyo Chemical Industries, Ltd., trade name “Sanfloc R-335P”, [η] 10 (dl / g), cation colloid equivalent 2.9 meq / g, anion colloid equivalent − The treatment of the present invention was carried out in the same manner as in Example 1 except that 10 parts of a 2.6% aqueous solution (2.6 meq / g) (solid content addition amount 0.01% / waste water) was used. The results are shown in Table 1.

Example 3
(A-1) In place of 10 parts, 10% polyferric sulfate aqueous solution [manufactured by Nippon Steel Mining Co., Ltd., trade name “Polytec”] (a-2) 10 parts (solid content added 0.5% / Wastewater) was used in the same manner as in Example 1 except that the treatment of the present invention was performed. The results are shown in Table 1.

Example 4
After adding (b-1) and stirring, the same procedure as in Example 1 was carried out except that 10 parts of a 0.2% aqueous solution of (b-3) (solid content addition amount 0.01% / waste water) was used. The process of the invention was performed. The results are shown in Table 1.

Example 5
In the same manner as in Example 1, the waste water (waste water 1) was set in a jar tester, and while stirring, 10 parts of (a-1) (solid content addition amount 0.5% / waste water) was added and stirred sufficiently. After (about 3 minutes), dicyandiamide / formalin polycondensate (c-1) [manufactured by Sanyo Chemical Industries, trade name “Sunfix 70”, solid content concentration 52%, [η] 0.3 (dl / G), cation colloid equivalent 5.0 meq / g, and so on. ] Of 2% aqueous solution (0.008% solid content / waste water) was added and stirred for a sufficient time (about 3 minutes) (pH 4 after addition). The pH was adjusted to 7 using a 48% aqueous solution of sodium hydroxide, and then 4 parts of a 0.2% aqueous solution of (b-1) (solid content added 0.004% / waste water) was added to form a floc. Thereafter, a dehydrated cake was obtained in the same manner as in Example 1. The results are shown in Table 1.

Example 6
Mixed wastewater consisting of wastewater discharged in the solid-liquid separation step during the resin particle production process and wastewater discharged in the washing step (wastewater 2) [composition of main components in wastewater (A): styrene / acrylic resin ( (B): sulfonic acid surfactant, (C) carboxymethylcellulose, (D): calcium phosphate (volume average particle size 0.08 μm), and the content of each component in the wastewater is (A ): 0.02%, (D): 0.05%, (B): 0.7%, (C): 0.5%, pH is 7, COD value is 7,500 ppm, and so on. In the same manner as in Example 1, while setting in a jar tester, 5 parts (a-1) (solid content addition amount 0.25% / waste water) was added while stirring, and sufficient time (about 3 Min) and stirred (pH 4 after addition). The pH was adjusted to 7 using a 48% aqueous solution of sodium hydroxide, followed by polymer flocculant (b-4) [manufactured by Sanyo Chemical Industries, Ltd., trade name “Sanfloc AS-510P”, [η] 17 (dl / G), 4 parts of 0.2% aqueous solution (an added amount of 0.004% / waste water) of anionic colloid equivalent of −0.7 meq / g] was added to form a floc. Thereafter, a dehydrated cake was obtained in the same manner as in Example 1. The results are shown in Table 2.

Example 7
In the same manner as in Example 6, the waste water (waste water 2) was set in a jar tester, and while stirring, 5 parts of (a-1) (solid content addition amount 0.25% / waste water) was added and stirred sufficiently. After (about 3 minutes), polydimethyldiallylammonium chloride (c-2) [manufactured by Toagosei Chemical Industry Co., Ltd., trade name “Aron Flock C-70”, solid content concentration 20%, [η] 1.3 (Dl / g), cation colloid equivalent 6.2 meq / g] 2% aqueous solution 0.2 parts (solid content 0.002% / waste water) was added and stirred for a sufficient time (about 3 minutes) Later pH 4). The pH was adjusted to 7 using a 48% aqueous solution of sodium hydroxide, and then 6 parts of a 0.2% aqueous solution (b-4) (solid content added 0.006% / waste water) was added to form a floc. Thereafter, a dehydrated cake was obtained in the same manner as in Example 1. The results are shown in Table 2.

Example 8
Mixed wastewater consisting of wastewater discharged in the solid-liquid separation step during the resin particle production process and wastewater discharged in the washing step (wastewater 3) [composition of main components in wastewater (A): polyurethane resin (volume average Particle size 125 μm), (B): sulfonic acid surfactant, (C) carboxymethylcellulose, the content of each component in waste water is (A): 0.01%, (B): 0.1%, ( C): 0.01%, pH is 7, COD value is 700 ppm, and so on. In the same manner as in Example 1, using a jar tester, 0.4 part of (a-1) (solid content added 0.02% / waste water) was added while stirring, and stirred sufficiently. After (approx. 3 minutes), 0.5 part of 0.2% aqueous solution of (c-1) (solid content added 0.0005% / waste water) was added and stirred for a sufficient time (approx. 3 minutes) (addition) Later pH 5). The pH was adjusted to 7 using a 48% aqueous solution of sodium hydroxide, and then polymer flocculant (b-5) [manufactured by Sanyo Chemical Industries, Ltd., trade name “Sanflock AH-200P”, [η] 20 (dl / G), 0.2 part of 0.2% aqueous solution of anionic colloid equivalent -2.7 meq / g] (solid content added 0.0002% / waste water) was added to form floc. Thereafter, a dehydrated cake was obtained in the same manner as in Example 1. The results are shown in Table 3.

Example 9
Mixed wastewater consisting of wastewater discharged in the solid-liquid separation process during the resin particle production process and wastewater discharged in the washing process (wastewater 4) [composition of main components in wastewater (A): polyurethane resin (volume average Particle size 320 μm), (C): sodium polyacrylate, the content of each component in waste water is (A): 0.04%, (C): 0.3%, pH is 7, COD value is 1, 600 ppm] was set in a jar tester in the same manner as in Example 1 and 1.5 parts (a-1) (solid content addition amount: 0.075% / waste water) was added while stirring and sufficient time After stirring (about 3 minutes), 1 part of a 0.2% aqueous solution of (c-1) (solid content added 0.001% / waste water) was further added and stirred for a sufficient time (about 3 minutes) (addition) Later pH 5). Adjust pH to 7 using 48% aqueous sodium hydroxide, then add 0.5 part of 0.2% aqueous solution (b-1) (solid content 0.0005% / waste water) to form floc did. Thereafter, a dehydrated cake was obtained in the same manner as in Example 1. The results are shown in Table 4.

Comparative Example 1
Wastewater treatment was performed in the same manner as in Example 1 except that (b-1) was not used. The results are shown in Table 1.

Comparative Example 2
Except not using (a-1), the waste water treatment was performed in the same manner as in Example 1. However, the floc was not formed and the subsequent treatment became difficult, so the wastewater treatment was stopped.

Comparative Example 3
(A-1) was not used, and instead of 2 parts of the 0.2% aqueous solution of (b-1), a polymer flocculant (b-6) [manufactured by Sanyo Chemical Industries, Ltd. -009P ", [η] 5 (dl / g), cation colloid equivalent 4.8 meq / g] 0.2% aqueous solution 20 parts (solid content added 0.02% / waste water) Waste water treatment was performed in the same manner as in 1. The results are shown in Table 1.

Comparative Example 4
Wastewater treatment was performed in the same manner as in Example 6 except that (b-4) was not used. The results are shown in Table 2.

Comparative Example 5
(A-1) was not used, and instead of 4 parts of the 0.2% aqueous solution of (b-4), 20 parts of the 0.2% aqueous solution of (b-6) (0.02% solid content added / waste water) The wastewater treatment was performed in the same manner as in Example 6 except that was used. The results are shown in Table 2.

Comparative Example 6
Wastewater treatment was performed in the same manner as in Example 8 except that (b-5) and (c-1) were not used. The results are shown in Table 3.

Comparative Example 7
(A-1) and (c-1) were not used, and instead of 0.2 part of 0.2% aqueous solution of (b-5), 20 parts of 0.2% aqueous solution of (b-6) (solid content) Waste water treatment was carried out in the same manner as in Example 8 except that 0.02% addition amount / waste water) was used. The results are shown in Table 3.

Comparative Example 8
Mixed wastewater consisting of wastewater discharged in the solid-liquid separation step during the resin particle production process and wastewater discharged in the washing step (wastewater 5) [composition of main components in wastewater (A): polyurethane resin (volume average Particle size 540 μm), (C): sodium polyacrylate, the content of each component in waste water is (A): 0.02%, (C): 0.2%, pH is 7, COD value is 1, 100 pm] was set in a jar tester in the same manner as in Example 1, and 1 part of (a-1) (solid content added 0.05% / waste water) was added while stirring and a sufficient time (about After stirring for 3 minutes, 1 part of a 0.2% aqueous solution of (c-1) (solid content added 0.001% / waste water) was further added and stirred for a sufficient time (about 3 minutes) (after the addition). pH 5). Adjust pH to 7 using 48% aqueous sodium hydroxide, then add 0.5 part of 0.2% aqueous solution (b-1) (solid content 0.0005% / waste water) to form floc did. Thereafter, a dehydrated cake was obtained in the same manner as in Example 1. The results are shown in Table 4.

In addition, the composition in the main waste water in Tables 1-4 and each component of (a)-(c) are as follows.
Wastewater 1: (A) Polyester resin (volume average particle size 8 μm), (B) Sulfonic acid-based surface activity
Sex agent, (C) carboxymethylcellulose, (A1) styrene / methacrylic acid
Resin (volume average particle size 0.2μm)
Wastewater 2: (A) Styrene / acrylic resin (volume average particle size 12 μm), (B) sulfonic acid
Surfactant, (C) carboxymethylcellulose, (D) calcium phosphate
(Volume average particle size 0.08 μm)
Wastewater 3: (A) polyurethane resin (volume average particle size 125 μm), (B) sulfonic acid series
Surfactant, (C) Carboxymethylcellulose wastewater 4: (A) Polyurethane resin (volume average particle size 320 μm), (C) Polyacrylic acid
Sodium waste water 5: (A) polyurethane resin (volume average particle size 540 μm), (C) polyacrylic acid
Sodium inorganic flocculant (a-1): 10% polyaluminum chloride aqueous solution [manufactured by Taki Chemical Co., Ltd., trade name
“PAC250A”]
Inorganic flocculant (a-2): 10% polyferric sulfate aqueous solution [manufactured by Nippon Steel Mining Co., Ltd.
Tetsu "]
Polymer flocculant (b-1): Anionic polymer flocculant Sanflock AH-400P [Sanyo
Made by Seiko Kogyo Co., Ltd., [η] 25 (dl / g), anion colloid equivalent -5.3
meq / g]
Polymer flocculant (b-2): Cationic polymer flocculant Sanflock CH-959P [Sanyo
Manufactured by Seiko Industry Co., Ltd., [η] 13.5 (dl / g), cation colloid equivalent
4 meq / g]
Polymer flocculant (b-3): Amphoteric polymer flocculant Sanflock R-335P [Sanyo Chemical Industries (
Co., Ltd., [η] 10 (dl / g), cation colloid equivalent 2.9 meq / g
Anionic colloid equivalent-2.6 meq / g]
Polymer flocculant (b-4): Anionic polymer flocculant Sanfloc AS-510P [Sanyo
[Η] 17 (dl / g), anionic colloid equivalent −0.
7 meq / g]
Polymer flocculant (b-5): Anionic polymer flocculant Sanflock AH-200P [Sanyo
Manufactured by Kasei Kogyo Co., Ltd.
[Η] 20 (dl / g), anion colloid equivalent -2.7 meq / g]
Polymer flocculant (b-6): Cationic polymer flocculant Sanflock C-009P, [Sanyo
[Η] 5, cation colloid equivalent 4.8 meq / g, manufactured by Kasei Kogyo Co., Ltd.]
Organic coagulant (c-1): cationic organic coagulant dicyandiamide / formalin polycondensate [trade name “Sunfix 70”, manufactured by Sanyo Chemical Industries, Ltd., solid content concentration 52%,
[Η] 0.3 (dl / g), cation colloid equivalent 5.0 meq / g]
Organic coagulant (c-2): Cationic organic coagulant polydimethyldiallylammonium chloride [trade name “Aron Flock C-70”, manufactured by Toagosei Co., Ltd., solid content concentration 20%, [η] 1 .3 (dl / g), cation colloid equivalent 6.2 me
q / g]

  As is clear from Tables 1 to 4, when treated by the treatment method of the present invention (Examples 1 to 9), COD components in waste water are reduced, floc strength is improved [a floc having a large particle size is formed, It can be seen that the flocs once formed are not easily broken even under high agitation (300 rpm)], and are excellent in reducing the moisture content of the dehydrated cake and improving the clarification of the filtrate (removability of suspension). On the other hand, it can be seen that Comparative Examples 1 to 8 cannot exhibit sufficient effects and are inappropriate as a wastewater treatment method. Further, as apparent from Table 4, in Comparative Example 8, since the resin particles in the wastewater have a particle diameter exceeding 500 μm, they cannot be sufficiently aggregated, and unaggregated resin particles leak into the treatment liquid during filtration. However, as a result, it can be seen that the concentration of the suspension in the treatment liquid becomes high and a sufficient treatment effect cannot be exhibited.

  Since the wastewater treatment method of the present invention can exhibit a stable treatment effect on wastewater having a high COD value containing suspended resin particles and a high concentration of surfactant and / or water-soluble polymer, a large capital investment is required. In addition, wastewater treatment can be efficiently performed with low running cost and simple operation management. Further, flocs obtained by the treatment method of the present invention are easy to separate into solid and liquid, and can reduce the moisture content of the dehydrated cake, so that the incineration cost can be reduced. For this reason, it is suitable for the treatment of waste water discharged from a resin particle manufacturing factory or the like.

Claims (6)

In a method for treating waste water containing resin particles (A) having a volume average particle diameter of 0.0005 to 500 μm and a surfactant (B) and / or a water-soluble polymer (C), an inorganic flocculant (a) is used. A method for treating wastewater, comprising a step of adding, a step of adding a polymer flocculant (b), and a step of adding an organic coagulant (c) as necessary. The method for treating waste water according to claim 1, wherein (b) is a polymer flocculant in which an anionic and amphoteric polymer flocculant or a cationic and amphoteric polymer flocculant is used in combination. Wastewater from which (A) is obtained from a process comprising a water dispersion step (I), a solid-liquid separation step (II), and optionally a washing step (III), and wastewater is generated in (II) and / or (III) The method for treating wastewater according to claim 1 or 2. Step (I) is a dispersion of resin particles (A) in water by a dissolved resin suspension method in which resin particles (A) are formed using an aqueous dispersion of resin particles (A1) and / or inorganic particles (D) as a dispersion medium. The method for treating wastewater according to claim 3, which is a process. The addition amount (% by weight) of (a) to (c) is 0.0005 to 20, (b) is 0.00001 to 0.5, and (c) is 0 to 1 with respect to waste water. The method for treating wastewater according to any one of claims 1 to 4. An inorganic flocculant (a) and, if necessary, an organic coagulant (c) are added to the wastewater, and after adjusting the wastewater pH to 5 to 8, a polymer flocculant (b) is added to form a floc, and further solidified. The method for treating wastewater according to any one of claims 1 to 5, comprising a step of liquid separation.