JP4167972B2 - Organic sludge dewatering method - Google Patents

Description

  The present invention relates to a method for dewatering organic sludge, and a monomer mixture in which a specific monomer and a produced polymer are added with a crosslinkable monomer in a molar ratio that maintains water solubility with respect to the monomer. An ionic water-soluble polymer dispersion in an aqueous salt solution having a particle size of 100 μm or less or a water-in-oil emulsion is added to organic sludge in the state of dispersion and dehydrated by a dehydrator. The present invention relates to a method for dewatering organic sludge.

  Polymer flocculants are widely used as wastewater treatment chemicals and paper additives, and have already become industrially essential chemicals. The polymer flocculant is composed of a water-soluble polymer substance, so when dissolved in water, it becomes a highly viscous solution. Conventionally, it is diluted to a concentration of about 0.05 to 0.3% by weight and added to waste water and sludge. I have done it. For this reason, a special dissolution apparatus for stirring the highly viscous liquid is necessary, and the installation location is also necessary, which places a certain burden on the capital investment plan.

  This polymer flocculant is mainly a powder product, but as a merit such that the dissolution time can be shortened, a water-in-oil emulsion or a dispersion polymer in brine is also developing in parallel. These two types are presumed to have some ingenuity in usage such as being soluble in the pipeline, and there is still room for development in the future. A method for adding a stock solution of a dispersion polymer product in salt water is disclosed in Patent Document 1. In other words, after adding a dilute aqueous solution of cationic polymer flocculant having an arbitrary form, an anionic water-soluble polymer in a dispersion solution in salt water is added in the state of a stock solution or dispersion to dehydrate organic sludge. However, this anionic water-soluble polymer has a property of dissolving only in neutral to acidic water, and is very inconvenient. On the other hand, water-in-oil emulsion products have a hydrophilic surfactant added after polymerization to improve water dispersibility, but if added in large amounts, the solubility in water-soluble polymer water is improved. The amount of addition is limited because the stability of is reduced. Therefore, even if this product is added in the state of a stock solution, it cannot be efficiently processed due to poor dissolution and dispersion in sludge. A prescription related to this is disclosed in US Pat. That is, when sludge is dewatered by a screw press type dehydrator, a water-in-oil emulsion product or a dispersion polymer solution in salt water is added to the sludge as it is or in an aqueous solution containing undissolved particles, and the sludge is removed from the sludge by the screw of the dehydrator. It is a formulation intended to increase the density of aggregated flocs by kneading dissolved particles and reaggregating them by dissolution.

JP-A-11-277094 Japanese Patent Application Laid-Open No. 07-031999

Conventionally, when sludge is dehydrated using a polymer flocculant commercially available as a dispersion, it is diluted with water to form a uniform aqueous solution and then added to the sludge. However, the present inventors examined the conventional addition method from two viewpoints. In other words, diluting and adding at a low concentration can provide the most suitable flocculation state when dehydrating with a dehydrator, and if the diluting device is omitted from the equipment side, the equipment investment can be reduced. It is. Therefore, the object of the present invention is to produce a most suitable agglomerated state when a high-concentration dispersion of a flocculant is not diluted with water but is poured as it is and then dehydrated with a dehydrator. The purpose is to provide a sludge dewatering formulation that improves the releasability from filter cloth and the like.

As a result of intensive studies to solve the above problems, the present inventors have reached the following invention. That is, the invention of claim 1 allows a water-soluble polymer that is soluble in the aqueous salt solution to coexist as a dispersant, and the monomer represented by the following general formula (1) and / or (2) is 5 to 100 mol%. The monomer represented by (3) is 0 to 50 mol%, the nonionic monomer is 0 to 95 mol%, and the polymer formed with respect to the total amount of these monomers is crosslinked at a molar ratio that maintains water solubility. Add the ionic water-soluble polymer dispersion with a particle size of 100 μm or less, which is produced by dispersion polymerization of the monomer mixture to which the ionic monomer is added, in an aqueous salt solution, to the organic sludge in the state of dispersion. The present invention relates to a method for dewatering organic sludge characterized by dewatering with a dewatering machine.

General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are an alkyl or alkoxyl group having 1 to ₃ carbon atoms or a benzyl group, R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group, They may be the same or different, A represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X ₁ represents an anion.

R ₅ represents hydrogen or a methyl group, R ₆ and R ₇ each represent an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X ₂ represents an anion.
General formula (2)
General formula (3)
R ₈ is hydrogen or CH ₂ COOY ₂ , Q is SO ₃ , C ₆ H ₄ SO ₃ ,
CONHC (CH ₃ ) ₂ CH ₂ SO ₃ , C ₆ H ₄ COO or COO, R ₉ is hydrogen,
A methyl group or COOY ₃ ; Y ₁ , Y ₂ , Y ₃ are hydrogen or a cation

A second aspect of the present invention, monomer 5 to 100 mol% represented by the following following general formula (1) and / or (2), monomer 0-50 mole% of the formula (3), the non It is immiscible with water and a monomer mixture in which a crosslinkable monomer is added at a molar ratio in which the polymer formed with respect to the total amount of ionic monomers is 0 to 95 mol% and the total amount of these monomers is water-soluble. In an oil consisting of an ionic water-soluble polymer produced by emulsifying and polymerizing an organic liquid with a surfactant so that the organic liquid becomes a continuous phase and a water-soluble monomer aqueous solution becomes a dispersed phase. An organic sludge dewatering method is characterized in that a water emulsion is added to organic sludge in a dispersion state and dehydrated by a dehydrator.
General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are an alkyl or alkoxyl group having 1 to ₃ carbon atoms or a benzyl group, R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group, They may be the same or different, A represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X ₁ represents an anion.

R ₅ represents hydrogen or a methyl group, R ₆ and R ₇ each represent an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X ₂ represents an anion.
General formula (2)
General formula (3)
R ₈ is hydrogen or CH ₂ COOY ₂ , Q is SO ₃ , C ₆ H ₄ SO ₃ ,
CONHC (CH ₃ ) ₂ CH ₂ SO ₃ , C ₆ H ₄ COO or COO, R ₉ is hydrogen,
A methyl group or COOY ₃ ; Y ₁ , Y ₂ , Y ₃ are hydrogen or a cation

The invention according to claim 3 is the method for dewatering organic sludge according to claim 2, wherein the surfactant has an HLB (hydrophobic hydrophilic balance) of 1 to 8.

The invention of claim 4 is the organic sludge dewatering method according to claim 2, wherein the surfactant has an HLB (hydrophobic hydrophilic balance) of 11-20.

The invention of claim 5 is characterized in that the ionic water-soluble polymer dispersion or the water-in-oil emulsion has a viscosity at 25 ° C. of 50 to 10,000 mPa · s. This is a method for dewatering organic sludge.

An excellent dehydration effect is achieved by the following mechanism of action. That is, when the dispersion or water-in-oil emulsion is added to the sludge, it is gradually dissolved on the particle surface by stirring, and the suspended particles in the sludge are aggregated. Once the sludge flocs are agglomerated, new floc surfaces appear and agglomerate due to the dissolved water-soluble polymer and agitation later, and further evolve into a dense agglomerated floc. As a result, it is considered that the cake dewatering rate is lowered by dewatering these high-density aggregated flocs. In addition, the use of a crosslinkable water-soluble polymer suppresses the spread of the molecule, and because it exists as a “dense-packed” molecular form, it binds to suspended particles at multiple points and does not form giant flocs, and has high strength. A floc is formed and the improvement of the sludge dewaterability is expressed. Another feature of the present invention is that it does not require dissolution equipment because it is poured in a highly concentrated dispersion state, and as a result, space for sludge dewatering equipment can be saved.

  In the present invention, a ionic water-soluble polymer dispersion or ion in an aqueous salt solution obtained by polymerizing a monomer mixture in which a crosslinkable monomer is added at a molar ratio that maintains the water solubility of a specific monomer and the produced polymer. Water-in-polymer polymer water-in-oil emulsion is added to organic sludge as a dispersion and dehydrated by a dehydrator. Conventionally, when sludge is dehydrated using an emulsion or dispersion type polymer flocculant, water is added to the flocculant and diluted. By this operation, the dispersion type flocculant is a common and commonly used addition method in which the dispersion is changed to a uniform aqueous solution at the time of dilution, and this is added to the sludge. However, the present inventors examined the conventional addition method from two viewpoints. In other words, diluting and adding at a low concentration can provide the most suitable flocculation state when dehydrating with a dehydrator, and if the diluting device is omitted from the equipment side, the equipment investment can be reduced. It is.

  As a result of examination from the above viewpoint, as compared with the conventional method of adding in the state of an aqueous solution diluted to a low concentration by securing an appropriate stirring state with the sludge, the high-concentration liquid product in a dispersed state is directly used as sludge. When added, it was found that excellent effects such as reduction of the moisture content of the dehydrated cake were exhibited. That is, when the dispersion or water-in-oil emulsion is added to the sludge, it is gradually dissolved on the particle surface by stirring, and the suspended particles in the sludge are aggregated. Once the sludge flocs are agglomerated, new floc surfaces appear and agglomerate due to the dissolved water-soluble polymer and agitation later, and further evolve into a dense agglomerated floc. As a result, it is considered that the cake dewatering rate is lowered by dewatering these high-density aggregated flocs.

  In this case, when the water-soluble polymer is crosslinked, the spread of the molecule in water is suppressed. Therefore, it exists as a more “dense” molecular form. It is considered efficient that the “density packed” molecular form is usually used as a crosslinkable polymer flocculant. When the cross-linked polymer flocculant is added to the sludge, it adsorbs to the suspended particles and acts as an adhesive between the particles, resulting in particle agglomeration. 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.

With the addition of the above-mentioned dispersion, “the same effect as when the aggregating agent is continuously added because the dispersed particles are gradually dissolved, the formation of a new aggregated surface of the aggregated flocs by stirring” and the suspension of the cross-linked polymer It seems that the improvement of sludge dewaterability is manifested by the multipoint connection on the surface of the turbid particles. Another feature of the present invention is that it does not require dissolution equipment because it is poured in a highly concentrated dispersion state, and as a result, space for sludge dewatering equipment can be saved.

The effect that the dissolution apparatus can be omitted is considered as follows. Polymer flocculants are widely used as wastewater treatment chemicals and papermaking additives, and are already industrially necessary chemicals. The polymer flocculants are composed of water-soluble polymer substances. Therefore, when it dissolves in water, it becomes a highly viscous solution. Conventionally, it has been diluted to a concentration of about 0.05 to 0.3% by mass and added to waste water and sludge. For this reason, a special dissolution apparatus for stirring the highly viscous liquid is necessary, and the installation location is also required, which imposes a certain burden on the capital investment plan. The elimination of these devices and land is a huge advantage.

The ionic water-soluble polymer dispersion in an aqueous salt solution used in the present invention is composed of a water-soluble monomer or a water-soluble monomer mixture, and a mole of the polymer formed with respect to the total amount of these monomers to maintain water solubility. A monomer mixture containing a crosslinkable monomer added in a ratio can be produced in a salt aqueous solution in the presence of a polymer dispersant. This manufacturing method can be manufactured by the method described in Japanese Patent Publication No. 4-39481 and Japanese Patent Publication No. 6-51755. The former publication discloses a method of coexisting a polyhydric alcohol as a dispersant during polymerization, and the latter publication coexists a soluble cationic polymer in an aqueous polyvalent anion salt solution as a dispersant during polymerization. A method is disclosed. These polymer dispersants can be used either ionic or nonionic. Nonionic polymers include polyvinyl pyrrolidone and polyvinyl alcohol. The ionic polymer is a polymer of an ionic vinyl monomer or a copolymer of an ionic vinyl monomer and a nonionic vinyl monomer, such as a polymer of acryloyloxyethyltrimethylammonium chloride, And a copolymer of acryloyloxyethyltrimethylammonium chloride and acrylamide.

As a method for producing a water-in-oil polymer emulsion, an ionic monomer, or an ionic monomer, a copolymerizable monomer, and a polymer formed with these monomers maintain water solubility. A monomer mixture containing a crosslinkable monomer added in a molar ratio has water, an oily substance consisting of at least water-immiscible hydrocarbons, and an HLB in an effective amount to form a water-in-oil emulsion. It is synthesized by mixing at least one type of surfactant, stirring vigorously to form a water-in-oil emulsion and polymerizing.

  Examples of oily substances composed of hydrocarbons used as dispersion media include paraffins, mineral oils such as kerosene, light oil, and middle oil, or hydrocarbon-based synthetics having characteristics such as boiling point and viscosity substantially in the same range as these. An oil or a mixture thereof may be mentioned. As content, it is the range of 20 weight%-50 weight% with respect to the total amount of water-in-oil emulsion, Preferably it is the range of 20 weight%-35 weight%.

  Examples of at least one surfactant having an amount effective to form a water-in-oil emulsion and HLB are HLB 1-8 nonionic surfactants, specific examples of which include sorbitan monooleate Sorbitan monostearate, sorbitan monopalmitate and the like. The addition amount of these surfactants is 0.5 to 10% by weight, preferably 1 to 5% by weight, based on the total amount of the water-in-oil emulsion.

In this case, the emulsion emulsified with a high HLB surfactant to form a water-in-oil emulsion and polymerized is compatible with water as it is, so there is no need to add a phase inversion agent. The HLB of these surfactants is 9-20, preferably 11-20. Examples of such surfactants are cationic surfactants and HLB 9-15 nonionic surfactants, such as polyoxyethylene polyoxypropylene alkyl ether systems, polyoxyethylene alcohol ether systems, and the like It is.

  When emulsified and polymerized with a low HLB surfactant, after the polymerization, a hydrophilic interfacial modifier called a phase inversion agent is added to make the emulsion particles covered with the oil film easily compatible with water. The polymer is easily dissolved, diluted with water and used for each application. Examples of hydrophilic surfactants are cationic surfactants and nonionic surfactants of HLB 9-15, such as polyoxyethylene polyoxypropylene alkyl ether systems and polyoxyethylene alcohol ether systems. is there.

  The polymerization is carried out in a nitrogen atmosphere under a polymerization initiator such as 2,2′-azobis (amidinopropane) dichloride or 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl). Propane] A water-soluble azo polymerization initiator such as dihydrochloride or a water-soluble redox polymerization initiator such as ammonium persulfate and sodium bisulfite in combination is added, and radical polymerization is carried out with stirring.

  As the monomer represented by the general formula (1) used at the time of polymerization, (meth) acryloyloxyethyltrimethylammonium chloride, which is a quaternized product of a tertiary amino-containing monomer with methyl chloride or benzyl chloride, ( (Meth) acryloyloxy 2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzylammonium chloride, (meth) acryloyloxy 2-hydroxypropyldimethylbenzylammonium chloride (Meth) acryloylaminopropyldimethylbenzylammonium chloride. A dimethyldiallylammonium monomer represented by the general formula (2) can also be used, and examples thereof include dimethyldiallylammonium chloride and diallylmethylbenzylammonium chloride.

  When producing an amphoteric water-soluble polymer, in addition to the cationic and nonionic monomers, an anionic monomer represented by the general formula (3) is further copolymerized. For example, a sulfone group or a carboxyl group may be used, and both may be used in combination. Examples of the sulfone group-containing monomer are vinyl sulfonic acid, vinyl benzene sulfonic acid, 2-acrylamido 2-methylpropane sulfonic acid, and the like. Examples of the carboxyl group-containing monomer include methacrylic acid, acrylic acid, itaconic acid, maleic acid, and p-carboxystyrene.

Examples of nonionic monomers include (meth) acrylamide, N, N-dimethylacrylamide, vinyl acetate, acrylonitrile, methyl acrylate, 2-hydroxyethyl (meth) acrylate, diacetone acrylamide, and N-vinyl pyrrolidone. N-vinylformamide, N-vinylacetamide, acryloylmorpholine, acryloylpiperazine and the like.

The crosslinkable monomer is a monomer having a plurality of polymerizable double bonds such as methylene bisacrylamide or ethylene glycol di (meth) acrylate, or thermal crosslinking such as N, N-dimethylacrylamide monomer. An example is a sex monomer. The addition amount is 0.0005 to 0.1 mol%, preferably 0.0010 to 0.05%, more preferably 0.0015 to 0.03% with respect to the total weight of the monomer mixture. . In order to adjust the degree of polymerization, it is effective to use isopropyl alcohol in combination with 0.1 to 5% by weight of the monomer.

  If the dispersion in aqueous salt solution or the water-in-oil emulsion used in the present invention has a too high liquid viscosity, the ionic water-soluble polymer fine particles are difficult to disperse in the sludge. Therefore, the viscosity of the dispersion liquid is several tens to 20,000 mPa · s, preferably 50 to 10,000 mPa · s. The molecular weight of the cationic and / or amphoteric water-soluble polymer constituting the dispersion in salt water or the water-in-oil emulsion is 3 million to 20 million, more preferably 5 million to 10 million.

Applicable sludge is surplus sludge generated during biological treatment such as papermaking wastewater, chemical industrial wastewater, food industry wastewater, or organic sludge such as raw sludge, mixed raw sludge, surplus sludge, digested sludge, etc. . The amount of the dispersion in the aqueous salt solution or the water-in-oil emulsion used in the present invention to the organic sludge is such that the ratio of the polymer in the dispersion to the sludge solids is 0.1 to 1.0 by mass%. %, Preferably 0.2 to 0.8%.

(Synthesis Example 1) In a reaction vessel equipped with a stirrer and a temperature controller, 126.0 g of isoparaffin having a boiling point of 190 ° C to 230 ° C, 6.0 g of sorbitan monooleate and polyricinoleic acid / polyoxyethylene block copolymer 0 .6 g was charged and dissolved. Separately, 83.1 g of deionized water and 23.6 g of a 60% aqueous solution of acrylic acid (abbreviated as AAC) were mixed and neutralized with 22.4 g of a 35% aqueous sodium hydroxide solution. After neutralization, 126.7 g of 80% aqueous solution of acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), 34.0 g of 80% aqueous solution of methacryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMC), and acrylamide (abbreviated as AAM) 65.1 g of 50% aqueous solution and 4.0 g of methylenebisacrylamide 0.1% by weight aqueous solution (0.0022 mol% with respect to the monomer) were each collected and added to the acrylic acid solution, and completely dissolved. Further, the pH was adjusted to 4.01, the oil and the aqueous solution were mixed, and the mixture was emulsified with stirring by a homogenizer at 1000 rpm for 15 minutes. The monomer composition at this time is DMQ / DMC / AAC / AAM = 40/10/15/35 (mol%).

  After adding 2.0 g of isopropyl alcohol 40% aqueous solution (0.5% by weight of monomer) to the obtained emulsion, keeping the temperature of the monomer solution at 30 to 33 ° C. and performing nitrogen substitution for 30 minutes, 2,5′-Azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride 10% aqueous solution 0.35 g (0.02% by weight of monomer) was added and polymerized. The reaction was started. The reaction was completed at a reaction temperature of 32 ± 2 ° C. for 12 hours to complete the reaction. After the polymerization, 10.0 g of polyoxyethylene tridecyl ether (2.0% by weight with respect to the liquid) was added to and mixed with the resulting water-in-oil emulsion as a phase inversion agent to prepare a sample for use in the test (Sample-1). . Moreover, the weight average molecular weight was measured with the molecular weight measuring device (DLS-7000 by Otsuka Electronics) by a static light scattering method. The composition is shown in Table 1, and the results are shown in Table 2.

(Synthesis Example 2) A water-in-oil emulsion having a monomer composition DMQ / AAM = 60/40 (mol%) was polymerized by the same operation as in the synthesis example, and a phase inversion agent was added to prepare Sample-2. The composition is shown in Table 1 and the results are shown in Table 2.

(Synthesis Example 3) In a reaction vessel equipped with a stirrer and a temperature control device, 10.0 g of polyoxyethylene tridecyl ether (2.0% by weight of the liquid) was added to 126.0 g of isoparaffin having a boiling point of 190 ° C to 230 ° C. Charge and dissolve. Separately, 83.1 g of deionized water and 23.6 g of a 60% aqueous solution of acrylic acid (abbreviated as AAC) were mixed and neutralized with 22.4 g of a 35% aqueous sodium hydroxide solution. After neutralization, 126.7 g of 80% aqueous solution of acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), 34.0 g of 80% aqueous solution of methacryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMC), and acrylamide (abbreviated as AAM) 65.1 g of 50% aqueous solution and 4.0 g of methylenebisacrylamide 0.1% by weight aqueous solution (0.0022 mol% with respect to the monomer) were each collected and added to the acrylic acid solution, and completely dissolved. Further, the pH was adjusted to 4.01, the oil and the aqueous solution were mixed, and the mixture was emulsified with stirring by a homogenizer at 1000 rpm for 15 minutes. The monomer composition at this time is DMQ / DMC / AAC / AAM = 40/10/15/35 (mol%).

  After adding 2.0 g of isopropyl alcohol 40% aqueous solution (0.5% by weight of monomer) to the obtained emulsion, keeping the temperature of the monomer solution at 30 to 33 ° C. and performing nitrogen substitution for 30 minutes, 2,5′-Azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride 10% aqueous solution 0.35 g (0.02% by weight of monomer) was added and polymerized. The reaction was started. The reaction was completed at a reaction temperature of 32 ± 2 ° C. for 12 hours to complete the reaction (Sample-3). The composition is shown in Table 1 and the results are shown in Table 2.

(Comparative Synthesis Example 1) In a reaction vessel equipped with a stirrer and a temperature controller, 126.0 g of isoparaffin having a boiling point of 190 ° C. to 230 ° C. and 10.0 g of polyoxyethylene tridecyl ether (2.0% by weight of the liquid) Was charged and dissolved. Separately, 83.1 g of deionized water and 23.6 g of a 60% aqueous solution of acrylic acid (abbreviated as AAC) were mixed and neutralized with 22.4 g of a 35% aqueous sodium hydroxide solution. After neutralization, 126.7 g of 80% aqueous solution of acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), 34.0 g of 80% aqueous solution of methacryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMC), and acrylamide (abbreviated as AAM) Each 65.1 g of 50% aqueous solution was sampled and added to the acrylic acid solution to completely dissolve it. Further, the pH was adjusted to 4.01, the oil and the aqueous solution were mixed, and the mixture was emulsified with stirring by a homogenizer at 1000 rpm for 15 minutes. The monomer composition at this time is DMQ / DMC / AAC / AAM = 40/10/15/35 (mol%).

  After adding 2.0 g of isopropyl alcohol 40% aqueous solution (0.5% by weight of monomer) to the obtained emulsion, keeping the temperature of the monomer solution at 30 to 33 ° C. and performing nitrogen substitution for 30 minutes, 2,5′-Azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride 10% aqueous solution 0.35 g (0.02% by weight of monomer) was added and polymerized. The reaction was started. The reaction was completed at a reaction temperature of 32 ± 2 ° C. for 12 hours to complete the reaction. This sample is referred to as Comparative-1. The composition is shown in Table 1 and the results are shown in Table 2.

(Synthesis Example 4) Metacloyl in a 500 mL four-necked flask equipped with a thermometer, a stirrer, a nitrogen introduction tube, a monomer supply tube connected to a peristaltic pump (SMP-21 type, manufactured by Tokyo Rika Kikai Co., Ltd.) and a condenser 46.3 g of 80 wt% aqueous solution of oxyethyltrimethylammonium chloride (hereinafter abbreviated as DMC), 60.5 g of 80 wt% aqueous solution of acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), acrylic acid (hereinafter abbreviated as AAC) ) (20.6 g), 50% aqueous solution of acrylamide (hereinafter abbreviated as AAM) 36.5 g, 173.1 g of ion-exchanged water, 125.0 g of ammonium sulfate, acryloyloxyethyltrimethylammonium chloride homopolymer as a dispersant 30.0 g (20% by mass aqueous solution, viscosity 6450 mP a)) and 2.3 g of methylenebisacrylamide 0.1 mass% aqueous solution (0.0015 mol% to monomer) were each squeezed to adjust the pH to 3.3. At this time, the mol% of each monomer is DMC / DMQ / AAC / AAM = 20/30/20/30. Next, the temperature in the reactor was kept at 30 ± 2 ° C., and after replacing with nitrogen for 30 minutes, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] as an initiator was used. Polymerization was initiated by adding 1.2 g of a 1% aqueous solution of dihydrochloride (0.01% monomer). When the internal temperature was kept at 30 ± 2 ° C. and the reaction was carried out for 7 hours from the start of polymerization, 0.01% of the initiator was added to the above monomer, and the reaction was further completed for 7 hours. The dispersion monomer obtained had a squeeze monomer concentration of 23.5%, a polymer particle size of 10 μm or less, and a dispersion viscosity of 810 mPa · s. Moreover, the weight average molecular weight was measured with the molecular weight measuring device (DLS-7000 by Otsuka Electronics) by a static light scattering method. This is designated as Sample-4. The composition is shown in Table 1 and the results are shown in Table 2.

(Synthesis Example 5) DMQ / AAM = 60/40 (mol%) (sample) according to the same procedure as in Synthesis Example 4, depending on the monomer having a plurality of vinyl groups and other monomer compositions shown in Table 1. A dispersion polymerized product in a salt solution having a composition of −5) was synthesized. The composition is shown in Table 1 and the results are shown in Table 2.

(Comparative synthesis example 2) In a 500 mL four-necked flask equipped with a thermometer, a stirrer, a nitrogen introduction tube, a monomer supply tube connected to a peristaltic pump (SMP-21 type, manufactured by Tokyo Rika Kikai Co., Ltd.), and a condenser. 46.3 g of 80 wt% aqueous solution of iroxyethyltrimethylammonium chloride (hereinafter abbreviated as DMC), 60.5 g of 80 wt% aqueous solution of acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), acrylic acid (hereinafter referred to as AAC) Abbreviated) 20.6 g of 60 wt% aqueous solution, 36.5 g of 50% aqueous solution of acrylamide (hereinafter abbreviated as AAM), 173.1 g of ion-exchanged water, 125.0 g of ammonium sulfate, and acryloyloxyethyltrimethylammonium chloride alone as a dispersant. 30.0 g of union (20% by mass aqueous solution, viscosity 645 0 mPa · s) and the pH was adjusted to 3.3. At this time, the mol% of each monomer is DMC / DMQ / AAC / AAM = 20/30/20/30. Next, the temperature in the reactor was kept at 30 ± 2 ° C., and after replacing with nitrogen for 30 minutes, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] as an initiator was used. Polymerization was initiated by adding 1.2 g of a 1% aqueous solution of dihydrochloride (0.01% monomer). When the internal temperature was kept at 30 ± 2 ° C. and the reaction was carried out for 7 hours from the start of polymerization, 0.01% of the initiator was added to the above monomer, and the reaction was further completed for 7 hours. The dispersion monomer obtained had a squeeze monomer concentration of 23.5%, a polymer particle size of 10 μm or less, and a dispersion viscosity of 735 mPa · s. Moreover, the weight average molecular weight was measured with the molecular weight measuring device (DLS-7000 by Otsuka Electronics) by a static light scattering method. This is referred to as comparison-2. The composition is shown in Table 1 and the results are shown in Table 2.
(Table 1)
DMC: methacryloyloxyethyltrimethylammonium chloride DMQ: acryloyloxyethyltrimethylammonium chloride, AAC: acrylic acid, AAM: acrylamide, cross-linking agent addition amount: mol% to monomer, MBA; methylenebisacrylamide, product form; E: Water-in-oil emulsion products,
D: dispersion in salt aqueous solution,
(Table 2)
Dispersion viscosity: mPa · s, molecular weight: 10,000
E: Water-in-oil emulsion product, D: Dispersion in salt solution,

The sludge dewatering method of the present invention was carried out using food surplus sludge (pH 6.20, ss content 23,000 mg / L). The sludge was supplied at 0.5 m3 / hr to an agglomeration mixing tank equipped with a stirrer, and Sample-1 was supplied in a dispersion state with a product concentration of 163 mL / hr (vs. ss content 0.50% by mass). While observing the floc diameter of the agglomerated sludge, it was sent to a belt press dehydrator (raised one-sheet filter cloth type) for dehydration. Thereafter, the filter cloth peelability and the moisture content of the dehydrated cake discharged from the belt press dehydrator were measured (dried at 105 ° C. for 20 hours). The same operation was performed for Sample-2 to Sample-5. The results are shown in Table 3. Further, as a comparative test, each sample was dissolved in 0.3% by mass and then poured from a coagulation mixing tank. That is, the sludge was supplied at 0.5 m 3 / hr to an agglomeration mixing tank equipped with a stirrer, and 21.7 L / hr of the solution of Sample-1 was added (0.50 mass% with respect to ss). Thereafter, the floc diameter, filter cloth peelability and cake moisture content were measured in the same manner as in the Examples. Similarly, it carried out also about sample-4. Further, Comparative Sample-1 and Comparative Sample-2 were tested for the method of dissolving and adding the dispersion as it was. The results are shown in Table 3.











(Table 3)
Flock diameter: mm, cake moisture content: mass%, chemical dosage: ss mass%
Filter cloth peelability: Good in the order of ◯>Δ> ×.

The sludge dewatering method of the present invention was carried out using human waste surplus sludge (pH 7.15, ss content 20,000 mg / L). The sludge was supplied at 0.5 m 3 / hr to an agglomeration mixing tank equipped with a stirrer, and Sample-1 was supplied at a product concentration of 199 mL / hr in a dispersion state (0.7 mass% for ss). While observing the floc diameter of the agglomerated sludge, it was sent to a belt press dehydrator (raised one-sheet filter cloth type) for dehydration. Thereafter, the filter cloth peelability and the moisture content of the dehydrated cake discharged from the belt press dehydrator were measured (dried at 105 ° C. for 20 hours). The same operation was performed for Sample-2 to Sample-5. The results are shown in Table 4. Further, as a comparative test, each sample was dissolved in 0.3% by mass and then poured from a coagulation mixing tank. That is, the sludge was supplied at 0.5 m 3 / hr to an agglomeration mixing tank equipped with a stirrer, and 26.4 L / hr of the solution of Sample-1 was added (0.7 mass% with respect to ss). Thereafter, the floc diameter, filter cloth peelability and cake moisture content were measured in the same manner as in the Examples. Similarly, Comparative Sample-2 was also carried out. The results are shown in Table 4.
(Table 4)
Flock diameter: mm, cake moisture content: mass%, chemical dosage: ss mass%
Filter cloth peelability: Good in the order of ◯>Δ> ×.

Claims (5)

A water-soluble polymer that is soluble in the aqueous salt solution coexists as a dispersant, and is represented by the following general formula (1) and / or (2): 5 to 100 mol% of a monomer represented by (3) Monomers 0 to 50 mol%, nonionic monomers 0 to 95 mol%, and a monomer in which a crosslinkable monomer is added at a molar ratio that maintains the water solubility of the polymer produced with respect to the total amount of these monomers. An ionic water-soluble polymer dispersion liquid having a particle size of 100 μm or less produced by dispersion polymerization of a monomer mixture in an aqueous salt solution is added to organic sludge in a dispersion state and dehydrated by a dehydrator. A feature of organic sludge dehydration.





General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are an alkyl or alkoxyl group having 1 to ₃ carbon atoms or a benzyl group, R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group, They may be the same or different, A represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X ₁ represents an anion.

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






General formula (3)
R ₈ is hydrogen or CH ₂ COOY ₂ , Q is SO ₃ , C ₆ H ₄ SO ₃ ,
CONHC (CH ₃ ) ₂ CH ₂ SO ₃ , C ₆ H ₄ COO or COO, R ₉ is hydrogen,
A methyl group or COOY ₃ ; Y ₁ , Y ₂ , Y ₃ are hydrogen or a cation Monomer 5 to 100 mol% represented by the following following general formula (1) and / or (2), monomer 0-50 mole% of the formula (3), a non-ionic monomer 0 A monomer mixture containing a crosslinkable monomer at a molar ratio of 95 mol% and the total amount of these monomers to maintain water solubility and an organic liquid immiscible with water are added by a surfactant. A water-in-oil emulsion comprising an ionic water-soluble polymer produced by emulsifying and polymerizing an organic liquid as a continuous phase and a water-soluble monomer aqueous solution as a dispersed phase, and then adding a phase inversion agent as appropriate. A method for dewatering organic sludge, which is added to the organic sludge as it is and dehydrated by a dehydrator.

General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are an alkyl or alkoxyl group having 1 to ₃ carbon atoms or a benzyl group, R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group, They may be the same or different, A represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X ₁ represents an anion.

R ₅ represents hydrogen or a methyl group, R ₆ and R ₇ each represent an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X ₂ represents an anion.
General formula (2)
General formula (3)
R ₈ is hydrogen or CH ₂ COOY ₂ , Q is SO ₃ , C ₆ H ₄ SO ₃ ,
CONHC (CH ₃ ) ₂ CH ₂ SO ₃ , C ₆ H ₄ COO or COO, R ₉ is hydrogen,
A methyl group or COOY ₃ ; Y ₁ , Y ₂ , Y ₃ are hydrogen or a cation The method for dewatering organic sludge according to claim 2, wherein the surfactant has an HLB (hydrophobic hydrophilic balance) of 1 to 8. The method for dewatering organic sludge according to claim 2, wherein the surfactant has an HLB (hydrophobic hydrophilic balance) of 10 to 20. The method for dewatering organic sludge according to claim 1 or 2, wherein the ionic water-soluble polymer dispersion or water-in-oil emulsion has a viscosity at 25 ° C of 50 to 10,000 mPa · s.