JP5946166B2 - Sludge dewatering method - Google Patents

Description

The present invention relates to a sludge dewatering method. Specifically, after adding a cationic or amphoteric aqueous polymer having 70 to 100 moles of a specific structural unit, a specific structural unit of 70 to 100 mole% is added. The present invention relates to a sludge dewatering method characterized by adding a cationic or amphoteric aqueous polymer.

Various methods for sequentially adding two kinds of flocculant solutions in sludge dewatering have been disclosed. A method of adding an anionic flocculant after adding a cationic flocculant, and a method of adding a cationic polymer after adding an inorganic coagulant have been proposed. Patent Document 3 is a method of adding a crosslinkable cationic flocculant having a different composition after adding a polymerized cationic flocculant without the presence of a crosslinkable monomer. The cationic monomer copolymerization ratio of 60 mol% or 40 mol% is only described in the examples, and there is no description of a high cationic polymer of 70 to 100 mol%.

In order to improve the dewaterability of sludge, many water-soluble polymers having a crosslinkable or branched coexisting crosslinkable monomer are disclosed. Patent Document 4 and Patent Document 5 both disclose the use of a polymer of (meth) acrylic cationic monomer, acrylamide and a crosslinkable monomer as a sludge dehydrating agent. In the examples of these patent documents, a water-in-oil emulsion is used as the form, the copolymerization ratio of the (meth) acrylic cationic monomer is 50 to 60 mol%, and the (meth) acrylic cationic monomer is used. There is no description regarding highly cationic polymers such as a copolymerization rate of 80 to 100 mol% of the monomer. Furthermore, a blend of two or more kinds of polymers has been proposed for the purpose of improving the function. Patent Document 6 discloses a blend of a high-crosslinking polymer and a low-crosslinking polymer using a (meth) acrylic cationic monomer. Only mol% is described, and Patent Document 7
A formulation comprising a cationic polymer of 40-80 mol% crosslinkable polymer, a cationic polymer of 30-60 mol% crosslinkable amphoteric polymer and an acidic substance is disclosed.
JP-A-6-246300 JP-A-7-214100 JP 2009-72754 A Japanese Patent Laid-Open No. 2-219887 JP-A 61-293510 JP 2005-144346 A JP 2010-163538 A

An object of the present invention is to develop a sludge dewatering method that has good agglomeration and high cake moisture content reduction ability for sewage mixed raw sludge, sewage surplus sludge, sewage digested sludge, and various surplus sludge in a sewage treatment plant. The sludge dewatering method can be used as a commercial product that can be applied to various dehydrators, satisfies the requirement of reducing the moisture content of the dehydrated cake, and at the same time can respond to the increase in the amount of chemicals added, which is a difficult point of crosslinked or branched aqueous polymers. The development is to use (meth) acrylic monomers.

As a result of intensive investigations to solve the above problems, the present inventors have reached the invention described below. That is, after adding a cationic or amphoteric aqueous polymer (A) having 70 to 100 mol % of one of the structural units represented by the following general formulas (1) to (4), the general formula (1) Of the cationic or amphoteric aqueous polymer having the structural unit represented by (2), the cationic or amphoteric aqueous polymer (A) has a copolymerization rate different from that of the general formula (1) to A cationic or amphoteric aqueous polymer (B) having a structural unit represented by 70 to 100 mol% represented by (2), or a monomer different from the monomer used in the cationic or amphoteric aqueous polymer (A) Structural units 70 to 100 represented by a cationic or amphoteric aqueous polymer (B) or (5) having 70 to 100 mol % of structural units represented by the following general formulas (1) to (2) mosquitoes having a molar% It was found to be achieved by the addition of on-resistance or amphoteric aqueous polymer (B). The cationic or amphoteric aqueous polymer (B) is a structure represented by the following general formula (5) polymerized by adding a crosslinkable monomer of 20 to 300 ppm by mass with respect to all monomers at the time of polymerization. It is particularly preferred that it has a unit.
General formula (1)
(R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are alkyl or alkoxyl groups having 1 to ₃ carbon atoms, R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, or an alkoxyl group, and may be the same or different. , a is oxygen or NH, B represents an alkylene group or an alkoxylene group having 2 to 4 carbon atoms, X ₁ ^- represents respectively an anion)

General formula (2)
(R ₅ and R ₆ are hydrogen or a methyl group, R ₇ and R ₈ are an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X ₂ ⁻ represents an anion, respectively)

General formula (3)
R ₉ represents hydrogen or a methyl group, H ⁺ Z ⁻ represents an inorganic acid and / or an organic acid, and H ⁺ Z ⁻ = 0 when not neutralized.
General formula (4)
R _{10 and} R ₁₁ represent hydrogen or a methyl group, H ⁺ Z ⁻ represents an inorganic acid and / or an organic acid, and H ⁺ Z ⁻ = 0 when not neutralized.
General formula (5)
R ₁₂ is hydrogen or a methyl group, R ₁₃ and R ₁₄ are hydrogen, an alkyl or alkoxyl group having 1 to 3 carbon atoms, which may be the same or different, and R ₁₅ is an alkyl group or aryl group having 7 to 20 carbon atoms, A represents an oxygen atom or NH, B represents an alkylene group or an alkoxylene group having 2 to 4 carbon atoms, and X ₃ ⁻ represents an anion.

Cationic or amphoteric aqueous polymer (A) having 70 to 100 mol % of the structural units represented by the general formulas (1) to (4), or the structure represented by the general formula (5) The cationic or amphoteric aqueous polymer (B) having units of 70 to 100 mol % is in an oil having a water-immiscible hydrocarbon as a continuous phase and an aqueous solution of the cationic or amphoteric water-soluble polymer as a dispersed phase. It can be a water-type emulsion. Further, after the water-in-oil emulsion is produced, it can be agglomerated by emulsion breaking, and then dried to obtain a finely divided powder.

The emulsion breaker uses one or more emulsion breakers selected from an ionic surfactant, a nonionic surfactant having an HLB value of 11 to 20, and an oil-soluble polymer compound having a hydrophilic group and a hydrophobic group. The oil-soluble polymer compound is a copolymer of a monomer having a hydrophobic group and a monomer having a hydrophilic group. Examples of the monomer having a hydrophobic group include a monomer having an aromatic ring such as styrene or α-methylstyrene or an aromatic ring to which an alkyl group is added, an aromatic ring having 6 to 20 carbon atoms such as an α-olefin, or an aliphatic vinyl compound. It is. Moreover, the alkyl (meth) acrylate which has a C4-C18 alkyl group can also be used. Examples of the monomer having a hydrophilic group include dimethylaminopropyl (meth) acrylamide that is dialkylaminoalkylacrylamide, dimethylaminoethyl (meth) acrylate that is dialkylaminoalkyl (meth) acrylate, and the like.

The cationic or amphoteric aqueous polymer referred to in the present invention may be water-soluble or water-swellable depending on the addition amount of the crosslinkable monomer that coexists during polymerization or the monomer composition to be copolymerized. is there. These are collectively called aqueous polymer.
In the sludge dewatering method of the present invention, by first adding a cationic or amphoteric aqueous polymer having a specific structural unit of 70 to 100 mol % , a coagulation action mainly composed of neutralization of surface charge is expressed, Causes fine floc formation. Thereafter, a cationic or amphoteric aqueous polymer having 70 to 100 mol % of different specific structural units is added and stirred. This aqueous polymer has a crosslinked structure, and does not form a fluffy huge floc, but forms a strong floc having a size suitable for dehydration by a machine.

The production method is easier and less expensive than polyamidine-based aqueous polymers. As for the product form, a water-in-oil emulsion can be easily produced, and handling at a dehydration site is also easy. Furthermore, a powder form in which the water-in-oil emulsion is subjected to emulsion breakage, solidified, and granulated and dried can be produced on an industrial scale relatively easily.

Polyamidine-based water-based polymers are characterized by the ability to insolubilize and agglomerate low-molecular-weight organic substances generated in the process of microorganisms, such as mixed raw sludge, sewage sludge, or surplus sludge from wastewater from food processing and fishery processing. It is thought that there is, but it has been difficult to treat this action with a (meth) acrylic cationic or amphoteric polymer. One reason for this is that (meth) acrylic cationic or amphoteric polymers have a very high molecular weight and are suitable for producing large, high-strength flocs due to cross-linking and adsorption, but they are generated during microbial treatment. The sludge is highly hydrophilic and has a low fiber content. In order to agglomerate such sludge, it is presumed that an insolubilizing function not necessarily accompanied by neutralization of surface charge is necessary. The elements necessary for this function are thought to be related to molecular weight, cation equivalent, balance between hydrophilicity and hydrophobicity, but in the present invention, molecular weight adjustment, high cationicity, polymerization with addition of a crosslinking agent, and high crosslinkability. It is thought that this was achieved by using a polymer.

With only the cationic or amphoteric aqueous polymer (A), the amount of the drug required for a good dehydration state is 2 to 3 times that of the polyamidine water-soluble polymer. On the other hand, only the cationic or amphoteric aqueous polymer (B) cannot reach the dehydrated cake water content of the polyamidine-based water-soluble polymer. Surprisingly, however, when both aqueous polymers are sequentially added at a constant ratio and the sludge is treated, it can have a dehydrating property equal to or higher than that of the polyamidine water-soluble polymer. The following reasons can be considered as this cause. The cationic or amphoteric aqueous polymer (A) is adsorbed on the hydrophilic colloid component in the sludge to neutralize the surface charge. As a result, the colloid is hydrophobized to form fine flocs, and then cationic or amphoteric aqueous The composition is such that the polymer (B) grows larger and more dense and strong. Since this amphoteric aqueous polymer (B) has an aryl group such as benzyl and an alkyl group having 7 to 20 carbon atoms, the aggregated floc is easily hydrophobized and can be grown into a dense and strong floc.

The cationic or amphoteric aqueous polymer (A) of the present invention contains a cationic monomer, and if necessary, a nonionic monomer or an anionic monomer in the case of amphoteric, and polymerizes these monomer mixtures. Can be manufactured. At the time of polymerization, a crosslinkable monomer can be added as necessary to obtain a linear or crosslinkable polymer. The product form is not particularly limited, such as a water-in-oil emulsion, powder, or a dispersion in salt water, but a particularly preferred form is a powder obtained by finely granulating and drying a water-in-oil emulsion or a water-in-oil emulsion after emulsion breakage. Type. By adopting this form, the performance of the crosslinkable aqueous polymer can be sufficiently exhibited, and the performance of the water-in-oil emulsion can be maintained as it is by drying the water-in-oil emulsion by the above method.

The cationic or amphoteric aqueous polymer (B) contains a cationic monomer and a crosslinkable monomer, and optionally contains a nonionic monomer or an anionic monomer in the case of amphoteric, The mixture can be polymerized and produced. The product form is not particularly limited, such as a water-in-oil emulsion, powder, or a dispersion in salt water, but a particularly preferred form is a powder obtained by finely granulating and drying a water-in-oil emulsion or a water-in-oil emulsion after emulsion breakage. Type. The difference between the cationic or amphoteric aqueous polymer (A) and the cationic or amphoteric aqueous polymer (B) is as follows. The cationic or amphoteric aqueous polymer (B) does not include the aqueous polymer having the structural units of the general formula (3) and the general formula (4), and the structural unit of the general formula (1). When the aqueous polymer having is first added,
An aqueous polymer having a copolymerization rate different from that of the aqueous polymer having the structural unit of the general formula (1) or an aqueous polymer produced by polymerizing different monomers in the range of the structural unit of the general formula (1) It is. As the cationic or amphoteric aqueous polymer (B), an aqueous polymer in which the cationic monomer used has an alkyl group or aryl group having 7 to 20 carbon atoms can also be used.

Cationic monomers used in the cationic or amphoteric aqueous polymer (A) include the following. That is, the structural unit represented by the general formula (1) is a single unit obtained by quaternizing dimethylaminoethyl (meth) acrylate or dimethylaminopropyl (meth) acrylamide with a halide of a lower alkyl group such as methyl chloride or ethyl chloride. The body is polymerized. Examples thereof include (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxy-2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, and the like. The structural unit represented by the general formula (2) is obtained by polymerizing diallylmethylammonium chloride or diallyldimethylammonium chloride. The structural unit represented by the general formula (3) is an aqueous polymer having a vinylamine structural unit, and is produced by hydrolysis of a polymer or copolymer of N-vinylformamide or N-vinylacetamide with an acid or alkali. can do. Furthermore, the structural unit represented by the general formula (4) is an aqueous polymer having a vinylamidine structural unit, and is produced by hydrolysis of N-vinylformamide or a copolymer of N-vinylacetamide and acrylonitrile with an acid. Can do.

When producing an aqueous polymer comprising an amphoteric water-in-oil emulsion, a vinyl anionic monomer is used in combination with the vinyl cationic monomer. Examples thereof include vinyl sulfonic acid, vinyl benzene sulfonic acid or 2-acrylamido-2-methylpropane sulfonic acid, methacrylic acid, acrylic acid, itaconic acid, maleic acid, phthalic acid, and p-carboxystyrene acid.

When copolymerizing nonionic monomers, (meth) acrylamide, N, N-dimethylacrylamide, acrylonitrile, 2-hydroxyethyl (meth) acrylate, diacetone acrylamide, N-vinylpyrrolidone, N- Vinylformamide, N-vinylacetamide, acryloylmorpholine and the like can be mentioned.

The copolymerization ratio of the cationic or amphoteric aqueous polymer (A) is as follows. They are 70-100 mol% of cationic monomers, 0-30 mol% of anionic monomers, and 0-30 mol% of nonionic monomers. However, since it is used as a sludge dehydrating agent in the present invention, the cationicity needs to be high to some extent, and preferably, the cationic monomer is 80 to 100 mol%, the anionic monomer is 0 to 20 mol%, and the nonionic It is 0-20 mol% of a sex monomer. The copolymerization ratio of the cationic or amphoteric aqueous polymer (B) is also in the same range. Of the copolymerization ratio of the cationic or amphoteric aqueous polymer (A), the structural unit represented by the general formula (3) is controlled by the degree of hydrolysis of the N-vinylformamide or N-vinylacetamide (co) polymer. The vinylamine structural unit is 70 to 100 mol%, preferably 80 to 100 mol%. Moreover, the structural unit represented by the general formula (4) can be adjusted by the acid hydrolysis degree of N-vinylformamide and an acrylonitrile copolymer and amidine formation, and the vinylamidine structural unit is 70 to 100. It is mol%, Preferably it is 80-100 mol%. Further, the cationic or amphoteric aqueous polymer (A) can also be made into a crosslinkable polymer by using a crosslinkable monomer described in the later paragraph during polymerization. This crosslinkable monomer is 20 to 5,000 ppm by mass with respect to the total amount of the monomers, and preferably 20 to 2,000 ppm.

In order to produce the cationic or amphoteric aqueous polymer (A) or the cationic or amphoteric aqueous polymer (B), a structural modifier, that is, a crosslinkable monomer that structurally modifies the polymer is used during polymerization. . This crosslinkable monomer is present in a mass of 20 to 5,000 ppm, preferably 50 to 2,000 ppm, based on the total amount of monomers. Examples of the crosslinkable monomer include N, N-methylenebis (meth) acrylamide, triallylamine, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and dimethacrylic acid. Acid-1,3-butylene glycol, polyethylene glycol di (meth) acrylate, N-vinyl (meth) acrylamide, N-methylallylacrylamide, glycidyl acrylate, polyethylene glycol diglycidyl ether, acrolein, glyoxal, vinyltrimethoxysilane In this case, the crosslinking agent is more preferably a water-soluble polyvinyl compound, and most preferably N, N-methylenebis (meth) acrylamide. Also, using a chain transfer agent such as sodium formate, isopropyl alcohol, sodium methallyl sulfonate, etc. is also effective as a method for adjusting the cross-linking property. The amount added is 0.001 to 1.0% by mass, preferably 0.01 to 0.1% by mass relative to the total amount of monomers.

Examples of the cationic monomer used in the polymerization for producing the cationic or amphoteric aqueous polymer (B) include the following. That is, it is a quaternized product of dimethylaminoethyl (meth) acrylate or dimethylaminopropyl (meth) acrylamide with benzyl chloride or a halide having an alkyl group or aryl group having 7 to 20 carbon atoms. Examples of the monomer represented by the general formula (5) include (meth) acryloyloxyethylbenzyldimethylammonium chloride, (meth) acryloyloxy-2-hydroxypropylbenzyldimethylammonium chloride, and (meth) acryloylaminopropyl. Such as benzyldimethylammonium chloride. The nonionic monomer used and the anionic monomer used when polymerizing the amphoteric aqueous polymer are the same as those of the cationic or amphoteric aqueous polymer (A). The copolymerization ratio of each monomer is also the same.

Both the aqueous polymers (A) and (B) used in the sludge dewatering method of the present invention preferably have a weight average molecular weight of 1,000,000 to 10,000,000, more preferably 1,000,000 to 8,000,000, more preferably 3,000,000 to 6,000,000. It is. The sludge dehydrating agent plays a major role in neutralizing the surface charge of the hydrophilic colloid, and this action does not necessarily require an ultra-high molecular weight aqueous polymer, and the cation equivalent value plays an important role. However, at the same time, it is necessary to form a strong floc that is tightened by aggregating action due to cross-linking adsorption, and a molecular weight higher than a certain level is required. Therefore, a weight average molecular weight becomes said range. This is considered to be related to the fact that the molecular weight of a flocculant composed of a polyamidine polymer currently on the market is 3 million to 5 million.

Examples of oily substances consisting of hydrocarbons used as dispersion media in the production of water-in-oil emulsions include paraffins, mineral oils such as kerosene, light oil, and middle oil, or boiling points and viscosities in substantially the same range as these. Hydrocarbon synthetic oils having these characteristics, or mixtures thereof. As content, it is the range of 20 mass%-50 mass% with respect to the water-in-oil type emulsion whole quantity, Preferably it is the range of 20 mass%-35 mass%.

Examples of at least one surfactant having an amount effective to form a water-in-oil emulsion and HLB are HLB 3-11 nonionic surfactants, specific examples of which include sorbitan monooleate, Examples include sorbitan monostearate, sorbitan monopalmitate, and polyoxyethylene nonylphenyl ether. The amount of these surfactants to be added is 0.5 to 10% by mass, preferably 1 to 5% by mass, based on the total amount of the water-in-oil emulsion.

After the polymerization, a hydrophilic surfactant called a phase inversion agent is added to make the emulsion particles covered with the oil film easy to adjust to water, and the water-soluble polymer therein is easily dissolved. Dilute with and use for each application. Examples of hydrophilic surfactants are cationic surfactants and HLB 9-15 nonionic surfactants, such as polyoxyethylene polyoxypropylene alkyl ethers and polyoxyethylene alcohol ethers.

The polymerization conditions are usually appropriately determined depending on the monomer used and the copolymerization mol%, and the temperature is in the range of 0 to 100 ° C. In particular, when the water-in-oil emulsion polymerization method is applied, it is carried out in the range of 20 to 80 ° C, preferably 20 to 60 ° C. For the initiation of polymerization, a radical polymerization initiator is used. These initiators may be either oil-soluble or water-soluble, and can be polymerized by any of azo, peroxide, and redox systems. Examples of oil-soluble azo initiators are 2,2′-azobisisobutyronitrile, 1,1-azobiscyclohexanecarbonitrile, 2,2′-azobis-2-methylbutyronitrile, 2,2 Examples include '-azobis-2-methylpropionate, 4,4'-azobis- (4-methoxy-2,4-dimethyl) valeronitrile.

Examples of water soluble azo initiators are 2,2'-azobis (amidinopropane) dichloride, 2,2'-azobis [2- (5-methyl-imidazolin-2-yl) propane] hydrogen dichloride And 4,4′-azobis (4-cyanovaleric acid). Examples of redox systems include a combination of ammonium peroxodisulfate and sodium sulfite, sodium hydrogen sulfite, trimethylamine, tetramethylethylenediamine and the like. Examples of peroxides include ammonium or potassium peroxodisulfate, hydrogen peroxide, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, succinic peroxide, t-butylperoxy-2-ethylhexanoate, and the like. Can be mentioned.

A production method of a type in which a water-in-oil emulsion is dried and pulverized is performed as follows. After the water-in-oil emulsion is produced, the emulsion is broken and solidified, and the solidified product is crushed or finely divided and dried. If further pulverization is required, pulverize and adjust the particle size to obtain a product.

A known method can be used as a method for causing an emulsion break. Particularly effective is a method of adding an emulsion breaker and breaking the emulsion by applying mechanical shear. Furthermore, an emulsion break can be efficiently performed by heating.

First, an emulsion break method using an emulsion breaker will be described. An emulsion break can be achieved by adding a surfactant to one of the emulsion break methods to change the emulsification balance. As the surfactant, an ionic surfactant or a nonionic surfactant having an HLB value of 11 to 20 is used. Examples of the nonionic surfactant include polyoxyethylene, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene polypropylene alkyl ether, and alkylamine.
Examples of ionic surfactants include anionic surfactants such as alkyl sulfonates, alkyl benzene sulfonates, and alkyl ether carboxylates, and cationic surfactants such as alkyl ammonium salts, alkyl trimethyl ammonium salts, and alkyl pyridinium salts. Is mentioned.

Next, a method for emulsion breaking with a polymer compound having a hydrophilic group and a hydrophobic group will be described. The polymer compound having a hydrophilic group and a hydrophobic group is preferably one that substantially dissolves in the oil phase that is the continuous phase of the W / O emulsion. When a polymer compound having a hydrophilic group and a hydrophobic group is added to a W / O emulsion, the hydrophilic group is adsorbed on the surface of the aqueous phase particles, eliminating the emulsifier at the interface and destabilizing the emulsified state. By doing so, the emulsified state can be destroyed. The polymer compound having a hydrophilic group and a hydrophobic group can be obtained by copolymerizing a monomer having a hydrophilic group and a monomer having a hydrophobic group.

Examples of the monomer having a hydrophilic group include methoxy or phenoxy polyethylene glycol (polymerization degree of polyoxyethylene, hereinafter referred to as n =, 4, 9 or 23) (meth) acrylate, polyethylene glycol (n = 4, 9 or 23). ) Mono (meth) acrylate, polyethylene glycol mono (meth) allyl ether, methoxypolyethylene glycol monoallyl ether and the like. Further, ionic monomers are more preferable. For example, dimethylaminopropyl (meth) acrylamide which is dialkylaminoalkyl acrylamide, dimethylaminoethyl (meth) acrylate which is dialkylaminoalkyl (meth) acrylate, (meth) acrylic acid, itacon Acid, fumaric acid, maleic acid,
Examples thereof include vinyl sulfonic acid, (meth) allyl sulfonic acid, sulfoethyl (meth) acrylate, styrene sulfonic acid, and acrylamide-2-methylpropane sulfonic acid.

Examples of the monomer having a hydrophobic group include a monomer having an aromatic ring such as styrene or α-methylstyrene or an aromatic ring to which an alkyl group is added, an aromatic ring having 6 to 20 carbon atoms such as an α-olefin, or an aliphatic vinyl compound. It is. Moreover, the alkyl (meth) acrylate which has a C4-C18 alkyl group can also be used. That is, butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate, butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, and the like.

If the ratio of the hydrophilic monomer is too large, it cannot be dissolved in the oil phase. On the other hand, if the ratio of the hydrophobic monomer is too large, the action as an emulsion breaker is weakened. The ratio of the hydrophobic monomer to the hydrophilic monomer is 90:10 to 30:70, preferably 70:30 to 40:60, as a molar ratio of hydrophobic monomer: hydrophilic monomer. is there. The average molecular weight of the polymer having a hydrophilic group and a hydrophobic group as measured by GPC is 5,000 to 100,000, preferably 10,000 to 50,000.

The polymer compound having a hydrophilic group and a hydrophobic group is preferably produced by solution polymerization in a hydrocarbon solvent of the same type as the hydrocarbon solvent used in the water-in-oil emulsion described later. By using a hydrocarbon solvent of the same type as the hydrocarbon solvent used in the water-in-oil polymer emulsion, workability is good when used as an emulsifier in the production of a water-in-oil polymer emulsion. Polymerization is performed at a monomer concentration of 20 to 80%, preferably 40 to 60%. The polymerization temperature is 30 to 180 ° C, preferably 40 to 150 ° C. For initiation of polymerization, an oil-soluble radical polymerization initiator is used. Polymerization can be carried out by any of azo, peroxide and redox systems, but azo is preferred. Examples of oil-soluble azo initiators are 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexanecarbonitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2-methylpropionate), 4,4-azobis (4-methoxy-2,4dimethyl) valeronitrile and the like.

The amount of emulsion breaker added is not particularly specified, but if the amount added is too small, the time required for emulsion break becomes too long. Since the emulsion breaker remains as an impurity after drying, it is not preferable that the amount added is too large. Therefore, the addition amount of the emulsion breaker is 0.1 to 10% by mass with respect to the liquid amount of the water-in-oil emulsion, preferably 0.5 to 5% by mass, and more preferably 0.5 to 3% by mass. It is.

In a system in which the emulsified state is unstable, an emulsion break can be caused only by applying a mechanical share. As a means for multiplying mechanical share, a method using a homogenizer or a mixer can be mentioned. Furthermore, an emulsion breaker can be caused in a short time by adding an emulsion breaker and multiplying the mechanical share.

Furthermore, an emulsion break can be efficiently caused by heating. The higher the heating temperature is, the shorter the time until the emulsion breaks is. However, when the heating temperature is too high, there is a problem that the hydrophilic polymer contained is deteriorated. Therefore, heating temperature is 50-150 degreeC, Preferably it is 70 degreeC-120.

The particle size can be controlled either before or after drying. In the case of controlling the particle size before drying, the method is not particularly limited, but a device for granulating a hydrogel such as a cutter, a meat chopper, and an extrusion molding machine is employed. Depending on the drying method, the agglomerate of hydrophilic polymer composed of a water-in-oil emulsion is pulverized and granulated to an appropriate size.

There is no restriction | limiting in particular in the drying method after granulation, Methods, such as hot air drying, conductive heat transfer drying, and radiant heat drying, can be used. In particular, hot air drying with good drying efficiency such as fluidized drying and aeration drying is preferable. By treating the solid matter dried after drying with a pulverizer or the like, fine particles having an average particle size on the order of micrometers can be obtained in addition to relatively large particles.

The present invention is an aggregating treatment agent comprising a crosslinkable aqueous polymer polymerized in the presence of a crosslinking agent. Moreover, the sludge recommended as a treatment target of the aqueous polymer of the present invention is sludge having a low fiber content such as digested sludge and surplus sludge generated by microbial treatment of each industrial wastewater. Or it is a sludge which contains many highly hydrophilic components, such as hydrophilic colloids, such as a mixture of surplus sludge and raw sludge. For these sludges with low fiber content, so-called linear water-soluble polymers are unlikely to form a strong floc that is applied to a sludge dewatering machine. That is, the linear water-soluble polymer exists in a state where the molecules are spread in water. It is considered that the aggregating action of a high-molecular weight cationic water-soluble polymer such as a polymerization system is caused by a binding action of a large number of suspended particles by a so-called “cross-linking adsorption action” by a molecular chain of the water-soluble polymer. However, the linear water-soluble polymer is in an extended state, and the aggregated floc formed by adsorbing the suspended particles therein is large but fluffy and difficult to become strong. Even if the amount added is increased to increase the strength, there is no improvement in floc. The cause of this is an extended state, so there are many contact sites with the suspended particles, and as a result, apparent charge saturation is likely to occur. It is only necessary to increase the agitation strength and destroy the generated floc to create a new adsorption surface. However, the above phenomenon occurs again, and eventually a small and strong floc is not generated.

On the other hand, the crosslinkable water-soluble polymer suppresses the spread of molecules in water by crosslinking. For this reason, it exists as a “density packed” molecular form, and when the crosslinking proceeds further, it becomes a water-swellable fine particle. The polymer flocculant usually used in the above-mentioned “density packed” molecular form is efficient when it is water-soluble. When the crosslinkable water-soluble polymer is added to the sludge, it adsorbs to the suspended particles and acts as an adhesive between the particles, resulting in aggregation of the particles. At this time, it is presumed that since it is in a “dense packed” molecular form, it binds to the particle surface at multiple points to form a tighter and stronger floc. Bonding at multiple points is excellent in adsorption performance to suspended particles, so that there are few unadsorbed water-soluble polymers, they are not released into sludge, and sludge viscosity does not increase. In addition, the cationic group present inside the molecule in a round shape does not contribute to charge neutralization of the suspended particles, but acts as a molecule with an apparently low degree of cationization, and is redispersed by cationic saturation. Will be less. As a result, it is considered that a strong floc that has been squeezed with a small size is formed, and when the machine is dehydrated, the water drainage is good and the moisture content of the cake decreases.

Polyamidine-based water-soluble polymers are characterized by the ability to insolubilize and agglomerate low-molecular organic substances generated during the process of microorganisms, such as mixed raw sludge from sewage, excess sludge, or excess sludge from wastewater from food processing and fishery processing. However, it has been difficult to treat this action with (meth) acrylic cationic or amphoteric polymers. One reason for this is that (meth) acrylic cationic or amphoteric polymers have a very high molecular weight and are suitable for producing large, high-strength flocs due to cross-linking and adsorption, but they are generated during microbial treatment. The insolubilizing function of the highly hydrophilic sludge that does not involve neutralization of the surface charge or necessarily neutralization of the surface charge was low. This is thought to be influenced by molecular weight, cation equivalent, balance between hydrophilicity and hydrophobicity. In the present invention, these factors are polymerized by adjusting molecular weight, adding high cationicity, and adding a crosslinking agent. It is thought that the polymer could be hydrophobized and controlled by using a polymer.

At present, there is no general method for displaying the degree of crosslinking of the crosslinkable polymer. In the above-mentioned Patent Document 2, it is defined by “ionic recovery rate”, and in Japanese Patent Application Laid-Open No. 2005-144346, “charge inclusion rate” is defined. These charges are measured by applying the fact that they are less likely to appear outside. Here, it will be explained first that the degree of crosslinking is expressed by measuring viscosity. The aqueous polymer of the present invention has an AQV as its 0.2% by weight aqueous solution viscosity, and SLV as its viscosity in a 0.5% by weight 1N saline solution of the amphoteric water-soluble polymer.
30 ≦ AQV / SLV ≦ 300 (at 25 ° C.)
It is preferable that This number can be used to represent the degree of crosslinking. Crosslinkable ionic water-soluble polymers are cross-linked in the molecule, and therefore have the property that molecules are difficult to spread in water, and should be less spread in water than linear polymers. However, as the degree of crosslinking increases, the viscosity when measured with a B-type viscometer (a type of rotational viscometer) increases. The cause is presumed to be due to friction or entanglement between the rotor of the B-type viscometer (rotor at the time of measurement) and the solution, but it is not exactly known. On the other hand, the viscosity of the crosslinkable ionic water-soluble polymer in salt water decreases as the degree of crosslinking increases. Since the molecule is contracted by the cross-linking, it is considered that the influence is greatly influenced by a large amount of ions in the salt water. Therefore, for these reasons, the ratio of the two viscosity measurements, AQV / SLV, increases as the degree of cross-linking increases (if the cross-linking progresses further and becomes water-insoluble, this relationship does not hold). In the crosslinkable cationic or amphoteric aqueous polymer of the present invention, this value is about 30 to 300. In view of the fact that this value is about 10 to less than 30 for a linear water-soluble polymer or a weakly crosslinked aqueous polymer, the crosslinkable cationic or amphoteric aqueous polymer of the present invention is highly crosslinked. It can be seen that this is a water-soluble polymer.

Further, the above-described charge inclusion rate will be described. The charge inclusion rate is defined as follows. That is, definition 1) In the case of a water-soluble cationic polymer and an amphoteric and water-soluble polymer having a positive difference in the copolymerization rate between a cationic monomer and an anionic monomer, the charge inclusion rate [%] = (1− α / β) × 100
α is a titration amount obtained by titrating a water-soluble cationic polymer or an amphoteric water-soluble polymer aqueous solution adjusted to pH 4.0 with acetic acid with a potassium polyvinyl sulfonate aqueous solution. β is a water-soluble cationic polymer or an amphoteric water-soluble polymer aqueous solution adjusted to pH 4.0 with acetic acid, and an aqueous polyvinyl sulfonate potassium solution is used to neutralize the charge of the water-soluble cationic polymer or amphoteric water-soluble polymer. A titration amount obtained by adding a sufficient amount to perform, and then subtracting the titration amount titrated with an aqueous polydiallyldimethylammonium chloride solution from the blank value. Here, the blank value is a titration amount obtained by titrating a potassium polyvinylsulfonate aqueous solution with a polydiallyldimethylammonium chloride aqueous solution when no water-soluble cationic polymer or amphoteric water-soluble polymer aqueous solution was added.
Definition 2) Charge inclusion ratio [%] = (1−α / β) × 100 in the case of a water-soluble polymer that is amphoteric and has a negative difference in copolymerization rate between a cationic monomer and an anionic monomer
α is a titration amount obtained by titrating a water-soluble amphoteric polymer aqueous solution adjusted to pH 10.0 with ammonia with a polydiallyldimethylammonium chloride aqueous solution. β is a water-soluble amphoteric polymer aqueous solution adjusted to pH 10.0 with ammonia, and a polydiallyldimethylammonium chloride aqueous solution is added in an amount sufficient to neutralize the charge of the water-soluble amphoteric polymer, and then a potassium polyvinyl sulfonate aqueous solution Titration volume obtained by subtracting the titration volume titrated with the blank value. Here, the blank value is a titration amount obtained by titrating a diallyldimethylammonium chloride aqueous solution with a potassium polyvinyl sulfonate aqueous solution when no water-soluble amphoteric polymer aqueous solution was added.

That is, it can be said that a water-soluble polymer having a high charge encapsulation rate is a water-soluble polymer having a high degree of crosslinking, and a water-soluble polymer having a low charge encapsulation rate is a water-soluble polymer having a low crosslinking rate. The reason for this is explained as follows. A linear water-soluble polymer has a substantially “stretched” shape in a dilute solution. On the other hand, the crosslinkable water-soluble polymer has a rounded particle shape in the solution, and the ionic group present inside the particle is unlikely to appear on the outside and reacts slowly with the opposite charge. It is thought to happen.

For crosslinkable water-soluble cationic polymers and crosslinkable water-soluble amphoteric polymers that are amphoteric and have a positive difference in the copolymerization rate between the cationic monomer and the anionic monomer, the charge inclusion rate is It becomes as follows.
Charge inclusion rate [%] = (1−α / β) × 100
The titration amount α is obtained by dropping an aqueous solution of potassium polyvinyl sulfonate having an opposite charge onto a crosslinkable cationic (amphoteric) water-soluble polymer as a sample, and then “surface” (particles) of the water-soluble cationic (amphoteric) polymer. Meaning an ionic electrostatic reaction on an ionic group present on the surface portion.

Next, potassium polyvinyl sulfonate having an opposite charge more than the amount sufficient to neutralize the theoretical charge amount of the crosslinkable cationic (amphoteric) water-soluble polymer was added, the reaction time was sufficient, and then the surplus Of polyvinyl sulfonate is titrated with an aqueous diallyldimethylammonium chloride solution. Separately, titrate the potassium polyvinyl sulfonate solution with diallyldimethylammonium chloride aqueous solution without adding a crosslinkable cationic (amphoteric) water-soluble polymer, and give a blank value. This value is β after subtracting the titration amount when the functional polymer is added. The β value is considered to correspond to the theoretical charge calculated from the chemical composition of the crosslinkable cationic (amphoteric) water-soluble polymer. In other words, the cross-linkable cationic (amphoteric) water-soluble polymer has a large amount of opposite charge, so it is considered that not only the surface cationic charge but also the internal charge is electrostatically neutralized. . If the degree of cross-linking is high, α is smaller than β, the (1-α / β) value is close to 1, and the charge inclusion rate is large (that is, the degree of cross-linking is high).

The charge inclusion rate of the crosslinkable water-soluble amphoteric polymer that is amphoteric and has a negative difference in the copolymerization rate between the cationic monomer and the anionic monomer can be explained in the same manner as described above. The only difference is that the pH is made alkaline with ammonia to dissociate the anionic group.

Regarding charge inclusion, 20% to 30% are weakly crosslinked aqueous polymers, 30% to 50% are moderately crosslinked aqueous polymers, and more than 50% are highly crosslinked aqueous polymers. it can. The aqueous polymer of the present invention is an aqueous polymer having a moderate degree of crosslinking of charge inclusion ratio of 30% or more. Here, AQV / SLV and the charge inclusion rate are compared. Sample-1 described in Table 1 of Paragraph 0059 is a highly crosslinked aqueous polymer having an AQV / SLV value of 47 and a charge inclusion rate of 38%. On the other hand, Comparative-1 was polymerized by coexisting the addition amount of the crosslinking monomer at a composition outside the range of the present invention, but the AQV / SLV value was 35 and the charge inclusion rate was 40%. Comparative-2 was polymerized without addition of a crosslinking monomer, and their values were 14 and 17%, which are almost linear polymers.

The agglomeration treatment agent comprising the aqueous polymer of the present invention is an organic sludge (so-called raw sludge, excess sludge, mixed raw sludge, digested sludge, coagulation / floating sludge, and mixtures thereof) produced in the treatment of sewage, human waste, and industrial wastewater. ) Is usually added as a 0.1 to 0.2 mass% aqueous solution. The addition amount is 0.2 to 2% by mass, preferably 0.3 to 1.0% by mass, as solid content with respect to sludge. Although not particularly limited to the target sludge, it is particularly effective and preferable for sludge having a low fiber content, sludge having a high organic content (VSS / SS), and sludge having a high degree of spoilage.

The addition ratio of the cationic or amphoteric aqueous polymer (A) to the cationic or amphoteric aqueous polymer (B) is preferably (A) :( B) = 90: 10 to 40:60 in terms of mass%. More preferably, (A) :( B) = 80: 20 to 50:50. If the addition amount of the cationic or amphoteric aqueous polymer (A) is higher than 90% by mass relative to the total addition amount, the water content during sludge dehydration increases, and if it is less than 40% by mass, the total addition amount increases, which is not preferable. The cationic or amphoteric aqueous polymer (A) may be a mixture of aqueous polymers polymerized by two different compositions (A). For example, a mixture of methacryloyloxyethyltrimethylammonium chloride homopolymer and acryloyloxyethyltrimethylammonium chloride homopolymer, or methacryloyloxyethyltrimethylammonium chloride homopolymer, copolymer of acryloyloxyethyltrimethylammonium chloride and acrylamide Such as a mixture.

The sludge dewatering method using the cationic or amphoteric water-soluble polymer of the present invention may be used for sludge dewatering using only an organic polymer, but can also be used in combination with an inorganic flocculant. Examples of the inorganic flocculant include salt iron, iron sulfate, polyiron, PAC, and sulfuric acid band. The addition amount with respect to sludge is 0.1-2 mass% normally with respect to sludge solid content, Preferably it is 0.3-1.0 mass%.

The type of dehydrator used can correspond to a belt press, a centrifugal dehydrator, a screw press, a multi-disc dehydrator, a rotary press, and the like.

(Examples) The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

(Production Example 1)
A reaction vessel equipped with a stirrer and a temperature controller was charged with 12.5 g of polyoxyethylene tridecyl ether (2.5% by mass of emulsion) and dissolved in 126.0 g of isoparaffin having a boiling point of 190 ° C. to 230 ° C. Separately, 103.1 g of deionized water, 250.0 g of an 80% aqueous solution of acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), and 2.0 g of a 1% by mass aqueous solution of methylenebisacrylamide (100 ppm relative to the monomer), respectively. Collected and mixed to dissolve completely. Thereafter, the pH was adjusted to 3.95, the oil phase and the aqueous solution were mixed, and the mixture was emulsified with stirring at 8000 rpm for 2 minutes with a homogenizer.

After adding 1.0 g of isopropyl alcohol 10 mass% aqueous solution (0.05 mass% monomer) to the obtained emulsion, maintaining the temperature of the monomer solution at 30 to 33 ° C. and performing nitrogen substitution for 30 minutes 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride 2.0 g (0.01% by weight monomer) was added. The polymerization reaction was started. The reaction was completed at a reaction temperature of 32 ± 2 ° C. for 12 hours to complete the reaction. This sample name is designated as Sample-1. Viscosity (AQV) when water-soluble polymer concentration is 0.1% by mass for sample to be used for test, B-type viscometer (rotational viscosity at 25 ° C. with viscosity (SLV) in 1N saline solution at 0.1% by mass) The charge inclusion rate and the weight average molecular weight by the light scattering method were measured with a PCD titration device manufactured by Mutech.

(Production Example 2)
A reaction vessel equipped with a stirrer and a temperature controller was charged with 12.5 g of polyoxyethylene tridecyl ether (2.5% by mass of emulsion) and dissolved in 126.0 g of isoparaffin having a boiling point of 190 ° C. to 230 ° C. Separately, 101.0 g of deionized water, 246.1 g of 80% aqueous solution of acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), 6.0 g (hereinafter abbreviated as AAM) of 50% by mass of acrylamide, and 1% by mass of methylenebisacrylamide Each 2.0 g (50 ppm by weight of monomer) was collected and mixed to dissolve completely. Thereafter, the pH was adjusted to 3.95, the oil phase and the aqueous solution were mixed, and stirred and emulsified with a homogenizer at 8000 rpm for 2 minutes.

After adding 1.0 g of isopropyl alcohol 10 mass% aqueous solution (0.05 mass% monomer) to the obtained emulsion, maintaining the temperature of the monomer solution at 30 to 33 ° C. and performing nitrogen substitution for 30 minutes 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride 2.0 g (0.01% by weight monomer) was added. The polymerization reaction was started. The reaction was completed at a reaction temperature of 32 ± 2 ° C. for 12 hours to complete the reaction. This is designated as Sample-2. Viscosity (AQV) when water-soluble polymer concentration is 0.1% by mass for sample to be used for test, B-type viscometer (rotational viscosity at 25 ° C. with viscosity (SLV) in 1N saline solution at 0.1% by mass) The charge inclusion rate and the weight average molecular weight by the light scattering method were measured with a PCD titration device manufactured by Mutech.

By the same operation, aqueous polymers having the compositions shown in Table 1, Sample-3 to Sample-13, and Comparative-1 to Comparative-2 were synthesized.

(Table 1)
DMC; methacryloyloxyethyltrimethylammonium chloride DMQ; acryloyloxyethyltrimethylammonium chloride DMBZ; acryloyloxyethyldimethylbenzylammonium chloride DMPQ; acryloylaminopropyltrimethylammonium chloride DD; diallyldimethylammonium chloride, MBA; methylenebisacrylamide, AAM; acrylamide ,

(Production Example 3)
Using the water-based polymer consisting of the water-in-oil emulsion described in Table 1 above, Sample-1, Sample-3, Sample-6, Sample-8, Sample-9, Sample-11, Comparison-1, and Comparison-2 Then, agglomeration by emulsion break, subsequent granulation, and a drying test were performed to prepare a powder type product.

100 g of Sample-1 was collected and 2.0 g of dimethylaminoethyl methacrylate and 2-ethylhexyl acrylate copolymer (copolymerization ratio 60 mol%: 40 mol%) (weight average molecular weight 16,100) were added, and a magnetic stirrer was added. And agglomerated by stirring. The emulsion-breaked lump was supplied to a meat chopper having a die diameter of 4.8 mm to form a granule having a particle diameter of 4 to 6 mm. Thereafter, the granular material was dried and powdered at 105 ° C. for 1 hour using a shelf-type ventilation dryer. The obtained dry powder was crushed with a screen having a pore diameter of 2 mm. Moreover, the average particle diameter of the obtained powder was measured. This powder is designated as Sample-20.

Similar operations were performed for Sample-3, Sample-6, Sample-8, Sample-9, Sample-11, Comparative-1, and Comparative-2, and the powder type aqueous polymer, Sample-21 to Sample-25, and Comparative -10 and Comparative-11 were prepared. The results are shown in Table 2.

(Table 2)

Example 1
A sludge dewatering test was carried out using the surplus sludge (pH 6.70, ss min. 19,200 mg / L) using the cationic or amphoteric aqueous polymer of the present invention. 200 mL was collected in a poly beaker, and samples-10 to 13 in Table 1 (both without any cross-linking agent) were added to each sludge SS 0.50%, and the beaker was transferred and stirred 20 times. After the test, Sample-1 and Sample-6 in Table 1 (both added with a cross-linking agent ) were each added with 0.3% of sludge SS content, the beaker was transferred and stirred 20 times, and then T-1179L. The filter cloth (made of nylon) was filtered, and the amount of filtrate after 10 seconds and the floc strength (size) were measured visually. Thereafter, the sludge filtered for 50 seconds is dehydrated at a press pressure of 3 kg / m ² for 1 minute. Thereafter, the filter cloth peelability was visually checked, and the cake water content (dried at 105 ° C. for 20 hours) was measured. The results are shown in Table 3.

(Comparative Example 1)
After adding Comparative-2 in Table 1 by the same operation as in Example 1, Sample-1, Sample-6 (all with a crosslinking agent added product) or Sample-9 (Crosslinking agent-free product) in Table 1 was added. The test was conducted according to the formulation to be added. The results are shown in Table 3.

The combination of sample -1 or sample -6 as Sample -10 Sample -13 a crosslinking agent additive-free products are crosslinking agent addition products, effects are out good results. Further, it can be seen that in the combination with Comparative-2, which is outside the scope of the present invention, the effect is lowered in any combination with Sample-1 to Sample-9.

( Table 3 )
Moisture content of cake: mass%, 10 seconds later, filtrate amount: mL, floc diameter: mm

(Example 2)
Using the same sludge used in Example 1, a sludge dewatering test was carried out using the cationic or amphoteric aqueous polymer of the present invention. Sample 200mL in a poly beaker, add Sample-1 to Sample-6 in Table 1 (both products with a cross-linking agent) to each sludge SS content 0.30%, transfer to the beaker and perform stirring 20 times. Then, sample-8 (addition agent for cross-linking agent ) in Table 1 was added to the sludge SS content 0.50%, and after the beaker was transferred and stirred 20 times, T-1179L filter cloth (made of nylon) was used. After filtration, the amount of filtrate after 10 seconds and the floc strength (size) were measured visually. Thereafter, the sludge filtered for 50 seconds is dehydrated at a press pressure of 3 kg / m ² for 1 minute. Thereafter, the filter cloth peelability was visually checked, and the cake water content (dried at 105 ° C. for 20 hours) was measured. The results are shown in Table 4.

(Comparative Example 2)
Tests were conducted on the combination of Comparative-1 (addition product with crosslinking agent) and Sample-8 (addition product with crosslinking agent) or Sample-11 (product without addition of crosslinking agent) in Table 1 in the same manner as in Example 2. did. The results are shown in Table 4.

The combination of sample -8 a sample -1 sample -6 a crosslinking agent addition products is a cross-linking agent added products, effects are out good results. In addition, it can be seen that in the combination with Comparative-1 which is outside the scope of the present invention, the effect is lowered in any combination with Sample-8 or Sample-11.

( Table 4 )
Moisture content of cake: mass%, 10 seconds later, filtrate amount: mL, floc diameter: mm

(Example 3)
Using sludge mixed raw sludge (pH 6.75, ss content 40,800 mg / L), a sludge dewatering test was carried out using the aqueous polymer of the present invention. 200 mL was collected in a poly-bicker, and the powdered sample -24 to sample -25 (all of which were not added with a crosslinking agent) in Table 2,
Alternatively, after adding Sample-20 to Sample-23 (both with a crosslinking agent) to the sludge SS content 0.45%, beaker-transferring and stirring 20 times, powdered sample-20 in Table 2 ~ Sample-23 (both with cross-linking agent added ) 0.40% of sludge SS content, beaker-transferred and stirred 20 times, filtered through T-1179L filter cloth (made of nylon), 10 The amount of filtrate after 2 seconds and the floc strength (size) were measured visually. Thereafter, the sludge filtered for 50 seconds is dehydrated at a press pressure of 3 kg / m ² for 1 minute. Thereafter, the filter cloth peelability was visually checked, and the cake water content (dried at 105 ° C. for 20 hours) was measured. The results are shown in Table 5.

(Comparative Example 3)
In the same manner as in Example 3, the combination of Comparison-10 (product with added crosslinking agent) or Comparison-11 (product without added crosslinking agent) and Sample-20 or Sample-22 (both products with added crosslinking agent) in Table 2 was combined. Tests were conducted on the prescribed formulations. The results are shown in Table 5.

The combination of sample -24 or sample -25 (both cross-linking agent additive-free product) and Sample -20 Sample 23 (both crosslinking agent addition product), specimen -20 Sample -23 and the sample 22 (crosslinked It can be seen that it is particularly better than the additive-added product. Moreover, it turns out that the effect is low in the combination of the comparative-10 (crosslinking agent additive-free product) or comparative 11 (crosslinking agent addition product) and the sample-20 or sample-22 which are outside the scope of the present invention. .

( Table 5 )
Moisture content of cake: mass%, 10 seconds later, filtrate amount: mL, floc diameter: mm

Claims (2)

After adding a cationic or amphoteric aqueous polymer (A) having 70 to 100 mol % of one of the structural units represented by the following general formulas (1) to (4), the general formulas (1) to ( Among the cationic or amphoteric aqueous polymers having the structural unit represented by 2), the cationic or amphoteric aqueous polymer (A) has a copolymerization rate different from those of the general formulas (1) to (2). A cationic or amphoteric aqueous polymer (B) having a structural unit represented by 70-100 mol%, or a monomer different from the monomer used in the cationic or amphoteric aqueous polymer (A). following formula was used (1) to cationic or amphoteric aqueous polymer (B) having a structural unit 70 to 100 mol% of the formula (2) or (5) structural unit represented by 70 to 100 mol% Cationic cation having There is an amphoteric aqueous polymer (B), the time of cationic or amphoteric aqueous polymer (B) is polymerized, polymerization by adding a crosslinking monomer 20~300ppm mass relative to the total monomer A cationic or amphoteric aqueous polymer (B) obtained in this manner, wherein the cationic or amphoteric aqueous polymer (A) and the cationic or amphoteric aqueous polymer (B) are water and non-aqueous. Cationic or amphoteric aqueous polymer having a miscible hydrocarbon as a continuous phase, a structural unit represented by the general formulas (1) to (4), or a structural unit represented by the general formula (5) (A ) Or a water-in-oil emulsion containing an aqueous solution of a cationic or amphoteric aqueous polymer (B) as a dispersed phase, and then agglomerated by emulsion breaking, dried and finely divided into powder. When Sludge dewatering how.
General formula (1)
(R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are alkyl or alkoxyl groups having 1 to ₃ carbon atoms, R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, or an alkoxyl group, and may be the same or different. , a is oxygen or NH, B represents an alkylene group or an alkoxylene group having 2 to 4 carbon atoms, _{X 1} ^- represents respectively an anion).

General formula (2)
(R ₅ and R ₆ are hydrogen or a methyl group, R ₇ and R ₈ are an alkyl group or an alkoxy group having 1 to 3 carbon atoms, and X ₂ ⁻ is an anion.)
General formula (3)
R ₉ represents hydrogen or a methyl group, H ⁺ Z ⁻ represents an inorganic acid and / or an organic acid, and H ⁺ Z ⁻ = 0 when not neutralized.

General formula (4)
R _{10 and} R ₁₁ represent hydrogen or a methyl group, H ⁺ Z ⁻ represents an inorganic acid and / or an organic acid, and H ⁺ Z ⁻ = 0 when not neutralized.
General formula (5)
R ₁₂ is hydrogen or a methyl group, R ₁₃ and R ₁₄ are hydrogen, an alkyl or alkoxyl group having 1 to 3 carbon atoms, which may be the same or different, and R ₁₅ is an alkyl group or aryl group having 7 to 20 carbon atoms, A represents an oxygen atom or NH, B represents an alkylene group or an alkoxylene group having 2 to 4 carbon atoms, and X ₃ ⁻ represents an anion. The emulsion break is performed by adding one or more emulsion breakers selected from an ionic surfactant and a nonionic surfactant having an HLB value of 11 to 20 to the water-in-oil emulsion. 2. The sludge dewatering method according to 1.