JP5630782B2 - Sludge dewatering agent and sludge dewatering method - Google Patents

Description

The present invention relates to a sludge dewatering agent. Specifically, a monomer mixture aqueous solution containing a specific monomer and an inorganic salt as an essential component, a water-immiscible organic liquid in a continuous phase by a surfactant, The present invention relates to a sludge dewatering agent comprising a water-in-oil emulsion produced by emulsifying and polymerizing an aqueous monomer mixture into a dispersed phase, and a sludge dewatering method using the same.

The polymer flocculant is generally dissolved in water and added to the treatment suspension, but since the aqueous solution is highly viscous, it needs to be added to the treatment suspension and properly stirred. However, performing a certain amount of agitation takes time and may affect efficient processing. Therefore, a prescription in which a salt is added to an aqueous solution obtained by polymerizing raw material monomers to reduce the viscosity has been proposed (Patent Document 1). This formulation is intended to increase the concentration of aqueous solution by reducing the apparent solution viscosity by adding 5 to 25% by mass of inorganic salt to a polymer obtained by polymerizing water-soluble monomers by various polymerization methods or before polymerization. It is a thing. Various polymerization methods describe suspension polymerization, but there is no description of a water-in-oil emulsion polymerization method or other specific production methods in the presence of a salt.

Patent Document 2 prepared an aqueous solution of at least one water-soluble monomer and contained a water-soluble and oil-insoluble salt from about 2 weight percent dissolved therein to the solubility limit in water. A method for producing a polymerized nonionic or anionic water-soluble polymer by emulsifying an aqueous solution in a water-insoluble hydrocarbon to form a water-in-oil emulsion is disclosed. However, this water-soluble polymer is not described with respect to cationicity or amphotericity, and there is no description about application as a dewatering agent for sludge using this water-soluble polymer.

As described above, when a polymer flocculant is added to the suspension to be treated and then stirred and mixed, a certain amount of stirring time is required. However, if the dispersibility in the suspension to be treated is improved, the aggregation function is improved. As a result, it can be expected that the optimum addition amount can be reduced.
JP-A-6-329866 JP 55-45783 A

The object of the present invention is to investigate a flocculant capable of improving the flocculation function by promoting the dispersibility of the flocculant in the turbid liquid to be treated and consequently reducing the amount of addition, and sludge dehydration prescription using the same. That is.

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 is a surfactant comprising an aqueous monomer mixture containing 30 to 100 mol% of a monomer represented by the following general formula (1) and / or (2) and an inorganic salt as essential components. In an oil composed of a water-soluble polymer having a weight average molecular weight of 3 to 10 million produced by emulsifying and polymerizing an immiscible organic liquid in water as a continuous phase and an aqueous monomer mixture solution as a dispersed phase. It is a water-type emulsion, and is a sludge dewatering agent comprising a water-in-oil emulsion having a 0.2% by mass aqueous solution viscosity at 25 ° C. of 350 mPa · s or less .
General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are alkyl groups having 1 to ₃ carbon atoms, alkoxy groups, and R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group, or a benzyl group. Different types may be used. 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.
General formula (2)
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.

The invention according to claim 2 is characterized in that the monomer mixture aqueous solution contains a monomer represented by the following general formula (3), wherein the sludge comprises a water-in-oil emulsion according to claim 1. It is a dehydrating agent.
General formula (3)
R8 is hydrogen, methyl or carboxymethyl ^{group, Q} represents ^{SO3 -, C6H4SO3 -, CONHC (} CH3) 2CH2SO3 -, C6H4COO - or ^COO -, R9 is hydrogen or ^COO - ^Y2 +, Y1 or Y2 is hydrogen or a cation Represent each.

The invention according to claim 3 comprises the water-in-oil emulsion according to claim 1 or 2, wherein the inorganic salt is 0.5 to 15% by mass with respect to the amount of the water-in-oil emulsion. It is a sludge dehydrating agent.

The invention according to claim 4 is an aqueous solution of a monomer mixture containing 30 to 100 mol% of a monomer represented by the following general formula (1) and / or (2) and an inorganic salt as essential components. Water-in- oil composed of a water-soluble polymer having a weight average molecular weight of 3 to 10 million produced by emulsifying and polymerizing a water-immiscible organic liquid in a continuous phase and an aqueous monomer mixture solution in a dispersed phase. A water-in- oil emulsion or a diluted liquid thereof having a viscosity of 350 mPa · s or less at 25 ° C. of the water-in-oil emulsion at 25 ° C. is added to the sludge for aggregation, and then dehydrated. This is a sludge dewatering method characterized by dewatering by a machine.
General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are alkyl groups having 1 to ₃ carbon atoms, alkoxy groups, and R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group, or a benzyl group. Different types may be used. 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.
General formula (2)
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.

The invention according to claim 5 is the sludge dewatering method according to claim 4, wherein the monomer mixture aqueous solution contains a monomer represented by the following general formula (3).
General formula (3)
R ₈ is hydrogen, methyl group or carboxymethyl group, 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 Represents hydrogen or COO ^— Y ₂ ⁺ , Y ₁ or Y ₂ represents hydrogen or a cation, respectively.

The sludge dewatering agent of the present invention comprises a monomer mixture aqueous solution containing a cationic monomer and an inorganic salt as essential components, a water-immiscible organic liquid in a continuous phase by a surfactant, and the monomer mixture aqueous solution. Is a water-in-oil emulsion produced by emulsifying and polymerizing to a dispersed phase. Further, not only cationic but also amphoteric polymers can be used. It is preferable that the said inorganic salt is 0.5-15 mass% with respect to the liquid quantity of a water-in-oil emulsion. The inorganic salt is preferably one having high solubility in the monomer aqueous solution, but a cation such as an alkali metal ion or ammonium ion such as sodium or potassium, a halide ion, a sulfate ion, a nitrate ion, a phosphate ion, or the like. A salt in combination with the anion of can be used. As specific salts, ammonium sulfate, sodium chloride, sodium sulfate, magnesium sulfate and the like are preferable, and ammonium sulfate is particularly preferable.

Since the sludge dewatering agent comprising the water-in-oil emulsion of the present invention is polymerized by adding an inorganic salt to the monomer aqueous solution during polymerization, a kind of salting-out effect also works to lower the apparent aqueous solution viscosity. As a result, dispersion in the turbid liquid to be treated, that is, sludge, is quickly manifested and the coagulation function is improved. With this effect, the addition amount in the vicinity of the optimum can be reduced. That is, when adding a polymer flocculant to the suspension to be treated and then stirring and mixing, a certain stirring time is required.
If the dispersibility in the turbid liquid to be treated is improved and the stirring time is shortened, the aggregation function is enhanced as a result, and the aggregation effect in a certain time is promoted, and the optimum addition amount is also reduced. is there.

As a method for producing a sludge dewatering agent comprising the water-in-oil emulsion of the present invention, a monomer mixture comprising a cationic monomer and an inorganic salt and, if necessary, a nonionic monomer or an anionic monomer is added to water. A water-in-oil emulsion composed of an oily water immiscible hydrocarbon, an amount effective to form a water-in-oil emulsion and at least one surfactant having HLB, and stirred vigorously. After forming, it is polymerized.

The cationic monomers used in the present invention include the following. That is, it is a quaternized product of methyl chloride or benzyl chloride such as dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, and methyldiallylamine. Examples of the monomer represented by the general formula (1) include (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxy-2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium. Chloride, (meth) acryloyloxyethyldimethylbenzylammonium chloride, (meth) acryloyloxy-2-hydroxypropyldimethylbenzylammonium chloride, (meth) acryloylaminopropyldimethylbenzylammonium chloride. Examples of the monomer represented by the general formula (1) include diallyldimethylammonium chloride.

When producing a papermaking drug 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 these monomers is as follows. They are 10-100 mol% of cationic monomers, 0-30 mol% of anionic monomers, and 0-60 mol% of nonionic monomers. However, since it is used as a sludge dehydrating agent in the present invention, it is necessary that the cationicity is high to some extent. Therefore, the cationic monomer is preferably 30 to 100 mol%, the anionic monomer 0 to 20 mol%, and the nonionic It is 0-50 mol% of a sex monomer.

The inorganic salt that is allowed to coexist in the monomer aqueous solution during polymerization is preferably one having high solubility in the monomer aqueous solution, but is as follows. That is, a salt in which a cation such as alkali metal ion or ammonium ion such as sodium or potassium and an anion such as halide ion, sulfate ion, nitrate ion or phosphate ion can be used. The concentration of these salts is 0.5% to 15% by mass with respect to the amount of the water-in-oil emulsion. As specific salts, ammonium sulfate, sodium chloride sodium sulfate, magnesium sulfate and the like are preferable, and ammonium sulfate is particularly preferable.

Examples of oily substances made of hydrocarbons used as a dispersion medium include paraffins, mineral oils such as kerosene, light oil, and middle oil, or hydrocarbons having characteristics such as boiling point and viscosity in substantially the same range as these. Synthetic oils or mixtures thereof may be mentioned. 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 weight, preferably 1 to 5% by weight, 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, etc. Can be mentioned.

The polymerization concentration of the monomer is in the range of 20 to 50% by mass, and preferably in the range of 25 to 40% by mass. Set.

In the water-in-oil emulsion polymerized in the presence of the inorganic salt of the present invention, the apparent viscosity of the aqueous solution decreases. For example, in a polymer composed of 20 mol% of acryloyloxyethyltrimethylammonium chloride and 80 mol% of acrylamide, a 0.2 mass% solution is 149 mP · s (B type viscometer, 25 ° C.). It can also be recognized from the fact that a 0.2% by mass solution of a polymer polymerized by ordinary water-in-oil emulsion polymerization is 526 mP · s.

A polymer produced by water-in-oil emulsion polymerization in the presence of an inorganic salt according to the present invention includes a polymer obtained by salting-out polymerization such as dispersion polymerization in an aqueous salt solution and JP-A-6-329866, cited in the background art. Can be considered as an intermediate polymer with a polymer polymerized in an aqueous solution in the presence of a salt. The polymer obtained by salting-out polymerization is completely salted out and insolubilized. A polymer obtained by polymerization in an aqueous solution in the presence of salt is in a state in which the polymer chain is somewhat contracted, but is considered to be in a state that is not so different from an aqueous solution in the absence of salt. On the other hand, the polymer produced by water-in-oil emulsion polymerization in the presence of an inorganic salt according to the present invention has a salt concentration of several to 10% by mass with respect to the monomer and is not in a state where salting-out occurs. . However, it is estimated that the monomer concentration is 50 to 70% by mass in the emulsion particles and is in a very high and unique situation. As described above, the viscosity of the diluent is also considerably lower than that of a normal water-in-oil emulsion polymer. If it is simply in a contracted state, it should show high viscosity if diluted, but it is not. Therefore, it may be crystallized or physically cross-linked. Therefore, it is considered that the polymer chain is in a compact state and the dispersibility is improved accordingly.

The molecular weight of the water-soluble polymer obtained by polymerizing these monomers is 3 million to 10 million, preferably 5 million to 8 million, as the weight average molecular weight by light scattering. In general, the higher the molecular weight, the better the coagulation performance, but a certain range of molecular weight is necessary to maintain rapid dispersibility in sludge. That is, when the weight average molecular weight is lower than 3 million, the aggregation performance is lowered, and when it is higher than 10 million, the dispersibility is lowered, which is not preferable and deviates from the gist of the present invention.

(Example)
The sludge dehydrating agent comprising the water-in-oil emulsion of the cationic or amphoteric polymer of the present invention will be specifically described by the following examples, but the present invention is not limited to the following examples.

A four-necked 500 ml separable flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube was charged with 120.0 g of isoparaffin having a boiling point of 190 ° C. to 230 ° C., 7.5 g of sorbitan monooleate and polyoxyethylene sorbitan monostearate 4 .25 g was charged and dissolved. Separately, 200.8 g of 80% by mass acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), 78.4 g of 50% by mass acrylamide (abbreviated as AAM), 0.2 g of isopropyl alcohol (0.1% by mass of monomer) 25.0 g of ammonium sulfate (5% by mass with respect to the total amount of the water-in-oil emulsion) and 55.0 g of ion-exchanged water were collected and added. The oil and the aqueous solution were mixed and emulsified with stirring at 1000 rpm for 2 minutes with a homogenizer. The monomer composition at this time is DMQ / AAM = 60/40 (mol%).

After maintaining the temperature of the obtained emulsion monomer solution at 40 to 43 ° C. and performing nitrogen substitution for 30 minutes, 0.7 g of dimethyl-2,2′-azobisisobutyrate (Wako Pure Chemical V-601) (0.35% by mass with respect to monomer) was added to initiate the polymerization reaction. The reaction was completed by polymerization at 42 ± 2 ° C. for 12 hours. After the polymerization, 9.0 g of polyoxyethylene decyl ether (1.8% by mass with respect to the liquid) was added and mixed as a phase inversion agent to the resulting water-in-oil emulsion. The weight average molecular weight of this water-in-oil emulsion measured by the light scattering method was 7 million. This prototype is designated as Sample-1.

DMQ / AAM = 60/40 (mol%, sodium chloride 5 mass%) (sample-2), DMQ / AAM = 60/40 (mol%, sodium sulfate 5 mass%) (Sample-3), DMQ / AAM = 60/40 (mol%, ammonium sulfate 2.5 mass%) (sample-4), DMQ / AAM = 60/40 (mol%, ammonium sulfate 10 mass%) (sample-5) ) , D MQ / AAM = 80/20 (mol%, ammonium sulfate 5 mass%) (sample-7), DMC = 100 (mol%, ammonium sulfate 5 mass%) (sample-8). The results are shown in Table 1.

A four-necked 500 ml separable flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube was charged with 120.0 g of isoparaffin having a boiling point of 190 ° C. to 230 ° C., 7.5 g of sorbitan monooleate and polyoxyethylene sorbitan monostearate 4 .25 g was charged and dissolved. Separately, 80% by mass acryloyloxyethyltrimethylammonium chloride 131.6 g, 80% by mass methacryloyloxyethyltrimethylammonium chloride 70.0 g, 60% by mass acrylic acid 17.0 g, 50% by mass acrylamide 57.0 g, isopropyl alcohol 0 .2 g (0.1% by mass with respect to the monomer), 25.0 g of ammonium sulfate (5% by mass with respect to the total amount of the water-in-oil emulsion), and 58.6 g of ion-exchanged water were collected and added. The oil and the aqueous solution were mixed and emulsified with stirring at 1000 rpm for 2 minutes with a homogenizer. The monomer composition at this time is DMQ / DMC / AAC / AAM = 40/20/10/30 (mol%).

After maintaining the temperature of the obtained emulsion monomer solution at 40 to 43 ° C. and performing nitrogen substitution for 30 minutes, 0.7 g of dimethyl-2,2′-azobisisobutyrate (Wako Pure Chemical V-601) (0.35% by mass with respect to monomer) was added to initiate the polymerization reaction. The reaction was completed by polymerization at 42 ± 2 ° C. for 12 hours. After the polymerization, 9.0 g of polyoxyethylene decyl ether (1.8% by mass with respect to the liquid) was added and mixed as a phase inversion agent to the resulting water-in-oil emulsion. The weight average molecular weight of this water-in-oil emulsion measured by the light scattering method was 7.1 million. This prototype is designated as Sample-9.

A four-necked 500 ml separable flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube was charged with 120.0 g of isoparaffin having a boiling point of 190 ° C. to 230 ° C., 7.5 g of sorbitan monooleate and polyoxyethylene sorbitan monostearate 4 .25 g was charged and dissolved. Separately, 200.8 g of 80% by mass acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), 78.4 g of 50% by mass acrylamide (abbreviated as AAM), 0.2 g of isopropyl alcohol (0.1% by mass of monomer) And ammonium sulfate 25.0 g (5% by mass with respect to the total amount of the water-in-oil emulsion), methylenebisacrylamide 0.1% by mass aqueous solution 3.0 g (based on the monomer 0.0015% by mass), ion-exchanged water 52.0 g Was collected and added. The oil and the aqueous solution were mixed and emulsified with stirring at 1000 rpm for 2 minutes with a homogenizer. The monomer composition at this time is DMQ / AAM = 50/50 (mol%).

After maintaining the temperature of the obtained emulsion monomer solution at 40 to 43 ° C. and performing nitrogen substitution for 30 minutes, 0.7 g of dimethyl-2,2′-azobisisobutyrate (Wako Pure Chemical V-601) (0.35% by mass with respect to monomer) was added to initiate the polymerization reaction. The reaction was completed by polymerization at 42 ± 2 ° C. for 12 hours. After the polymerization, 9.0 g of polyoxyethylene decyl ether (1.8% by mass with respect to the liquid) was added and mixed as a phase inversion agent to the resulting water-in-oil emulsion. The weight average molecular weight of this water-in-oil emulsion measured by the light scattering method was 8 million. This prototype is designated as Sample-10.

(Comparative Example 1)
A four-necked 500 ml separable flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube was charged with 120.0 g of isoparaffin having a boiling point of 190 ° C. to 230 ° C., 7.5 g of sorbitan monooleate and polyoxyethylene sorbitan monostearate 4 .25 g was charged and dissolved. Separately, 200.8 g of 80% by mass acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), 78.4 g of 50% by mass acrylamide (abbreviated as AAM), 0.2 g of isopropyl alcohol (0.1% by mass of monomer) Then, 80.0 g of ion-exchanged water was collected and added. The oil and the aqueous solution were mixed and emulsified with stirring at 1000 rpm for 2 minutes with a homogenizer. The monomer composition at this time is DMQ / AAM = 60/40 (mol%).

After maintaining the temperature of the obtained emulsion monomer solution at 40 to 43 ° C. and performing nitrogen substitution for 30 minutes, 0.7 g of dimethyl-2,2′-azobisisobutyrate (Wako Pure Chemical V-601) (0.35% by mass with respect to monomer) was added to initiate the polymerization reaction. The reaction was completed by polymerization at 42 ± 2 ° C. for 12 hours. After the polymerization, 9.0 g of polyoxyethylene decyl ether (1.8% by mass with respect to the liquid) was added and mixed as a phase inversion agent to the resulting water-in-oil emulsion. The weight average molecular weight of this water-in-oil emulsion measured by the light scattering method was 6.60 million. This prototype is referred to as Comparison-1, and the results are shown in Table 1.

(Comparative Example 2)
Using the same operation as in Example 2, a water-in-oil emulsion was produced under the condition of adding no salt. This prototype is referred to as Comparison-2, and the results are shown in Table 1.

(Comparative Example 3)
Using the same operation as in Example 3, a water-in-oil emulsion was produced under the condition of adding no salt. This prototype is referred to as Comparison-3, and the results are shown in Table 1.

( Table 1 )
DMQ; acryloyloxyethyltrimethylammonium chloride DMC; methacryloyloxyethyltrimethylammonium chloride, AAC; acrylic acid, AAM; acrylamide AS; ammonium sulfate, SC; sodium chloride, SS; sodium sulfate, cross-linking agent; Ppm relative to the mass of the mass)

Coagulation filtration test for centrifugal dehydrator for sewage mixed raw sludge generated from sewage treatment plant (sludge properties are pH 5.9, SS: 22000 mg / L, TS: 24500 mg / L, VSS: 88.4% / SS) And a squeeze test was conducted. After 200 mL of sludge was put into a 300 mL polypropylene beaker, Sample-1 to Sample- 5 and Sample-10 were added at 0.40 mass% and 0.60 mass% for SS, respectively, and stirred at 1000 rpm for 30 seconds. The sludge was agglomerated. Then, after observing the size of the floc, the filtration rate was examined with a 40 mesh beaker with a filter cloth. Further, the water content of the dehydrated cake was determined after press dewatering the aggregate after filtration for 30 seconds at a pressing pressure of 1 kgf / cm ² . The results are shown in Table 2.

(Comparative Example 4)
The same sludge as Example 4 was used and the same operation was implemented regarding Comparative-1 to Comparative-3 (each comparative sample). The results are shown in Table 2.

( Table 2 )
Drug addition amount: SS mass%, filtrate amount after 10 seconds; mL, cake moisture content; mass%, floc diameter; mm

Each sample of the example shows a sufficient coagulation effect even with the addition amount vs. sludge ss 0.4 mass%, but each sample of the comparative example has an addition amount vs. sludge ss 0.4 mass%.
Then the effect is insufficient. This is considered that each sample of the comparative example shows that the dispersibility of the drug in the sludge is lower than that of each sample of the example, and the coagulation action is delayed.

Coagulation filtration test for surplus sludge generated from human waste treatment plant (sludge properties are pH 6.7, SS: 14500 mg / L, TS: 16500 mg / L, VSS: 75.1% / SS) for belt press dehydrator And a squeeze test was conducted. After 200 mL of sludge was put into a 300 mL polypropylene beaker, Sample-1 and Sample-7 to Sample-10 were respectively added with 0.75% by mass and 0.95% by mass of sludge for SS, and the beaker was transferred 20 times. After agglomerating the sludge by observing the size of the floc, place a cylinder with an inner diameter of 60 mm on a filter cloth for belt press (T-1179L, manufactured by Shikishima Canvas Co.), and pour the agglomerated sludge in the beaker into it. The filtration rate was examined. Further, the water content of the dehydrated cake was determined after press dewatering the aggregate after filtration for 30 seconds at a pressing pressure of 1 kgf / cm ² . The results are shown in Table 3.

(Comparative Example 5)
A similar operation was performed for Comparative-1 to Comparative-3 using the same sludge as in Example 4. The results are shown in Table 3.

Each sample of the example shows a sufficient agglomeration effect even with the addition amount vs. sludge ss 0.75% by mass, but each sample of the comparative example is insufficient in effect with the addition amount vs. sludge ss 0.75% by mass. . This is considered that each sample of the comparative example shows that the dispersibility of the drug in the sludge is lower than that of each sample of the example, and the coagulation action is delayed.

(Table 3)
Drug addition amount: SS mass%, filtrate amount after 10 seconds; mL, cake moisture content; mass%, floc diameter; mm

Claims (5)

A monomer mixture aqueous solution containing 30 to 100 mol% of the monomer represented by the following general formula (1) and / or (2) and an inorganic salt as essential components is immiscible in water with a surfactant. A water-in-oil emulsion comprising a water-soluble polymer having a weight average molecular weight of 3 million to 10 million, which is produced by emulsifying and polymerizing an aqueous solution of the monomer mixture as a disperse phase and polymerizing. A sludge dewatering agent comprising a water-in-oil emulsion having a viscosity of 350 mPa · s or less of a 0.2% by mass aqueous solution of the water-in-water emulsion at 25 ° C.
General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are alkyl groups having 1 to ₃ carbon atoms, alkoxy groups, and R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group, or a benzyl group. Different types may be used. 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.
General formula (2)
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. The sludge dewatering agent comprising a water-in-oil emulsion according to claim 1, wherein the monomer mixture aqueous solution contains a monomer represented by the following general formula (3).
General formula (3)
R ₈ is hydrogen, methyl group or carboxymethyl group, 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 Represents hydrogen or COO ^— Y ₂ ⁺ , Y ₁ or Y ₂ represents hydrogen or a cation, respectively. The sludge dewatering agent comprising a water-in-oil emulsion according to claim 1 or 2, wherein the inorganic salt is 0.5 to 15% by mass with respect to the amount of the water-in-oil emulsion. A monomer mixture aqueous solution containing 30 to 100 mol% of the monomer represented by the following general formula (1) and / or (2) and an inorganic salt as essential components is immiscible in water with a surfactant. A water-in-oil emulsion comprising a water-soluble polymer having a weight average molecular weight of 3 million to 10 million, which is produced by emulsifying and polymerizing an aqueous solution of the monomer mixture as a disperse phase and polymerizing. A water-in- oil emulsion whose viscosity of a 0.2% by weight aqueous solution at 25 ° C. of a water-in-water emulsion is 350 mPa · s or less is added to a sludge and aggregated, and then dehydrated by a dehydrator. Sludge dewatering method.
General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are alkyl groups having 1 to ₃ carbon atoms, alkoxy groups, and R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group, or a benzyl group. Different types may be used. 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.
General formula (2)
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. The sludge dewatering method according to claim 4, wherein the monomer mixture aqueous solution contains a monomer represented by the following general formula (3).
General formula (3)
R ₈ is hydrogen, methyl group or carboxymethyl group, 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 Represents hydrogen or COO ^— Y ₂ ⁺ , Y ₁ or Y ₂ represents hydrogen or a cation, respectively.