JP2009039651A - Sludge dewatering agent and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop a sludge dewatering agent suitable for a screw press dehydrator by paying attention to the necessity of coagulability with good drainability during the early stage of dewatering as a function of a polymer coagulant required when sludge is dewatered by a screw press dehydrator to introduce the concept of crosslinking into a water-soluble polymer. <P>SOLUTION: In a sludge dewatering method where sewage-mixed raw sludge or sewage-digested sludge receives addition of a high molecular sludge dehydrator and then dewatered by a screw press dehydrator, as the high molecular sludge dehydrator, at least one is selected from among (a) a polyamidine-based water-soluble polymer, (b) a high cationic low molecular weight water-soluble polymer, and (c) a low crosslinkable water-soluble polymer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a sludge dewatering agent and a sludge dewatering method in the case of dewatering sludge using a screw press type dehydrator, and more particularly to a polymer sludge dewatering agent having a specific chemical composition, and sludge using the same. It relates to a dehydration method.

Currently, sludge dewatering machines such as centrifugal dewatering machines, belt presses, and rotary compression filters (rollary presses) are used, but screw press type dewatering machines include various types of sludge generated from paper mills. It has been used for organic sludge dewatering and fish protein recovery. In recent years, sealed press-fitting type screw press type dehydrators are being adopted in small and medium-sized treatment plants in order to demonstrate effectiveness against sludge that is relatively difficult to dehydrate. The press-fitted screw press type dehydrator is characterized in that the moisture content tends to decrease because the filter cake is dehydrated on the entire surface of the outer cylinder in the dehydrator. Therefore, it is attracting attention as a dehydrator for the next generation.

Conventionally, a dehydrating agent specifically developed for a belt press dehydrator has not been commercially available, and a water-soluble polymer that can be used in a selection test has been employed. For example, a water-soluble amphoteric polymer copolymerized with a methacrylate-based or acrylate-based cationic monomer (Patent Document 1), a water-soluble polymer containing a polyoxyethylene chain (Patent Document 2), or a cationic polymer flocculant In addition, it is disclosed to use a mixture (Patent Document 3) comprising an anionic polymer flocculant and a water-soluble salt.
When these patent documents are seen, there is no description example which paid attention to the point that the screw press type dehydrator needs cohesiveness with good water drainage in the early stage of dehydration. In addition, as for the water-soluble polymer necessary for this, there is no description example focusing on a water-soluble polymer incorporating the concept of crosslinking, or a mixture of an amidine-based water-soluble polymer and an acrylic water-soluble polymer.

JP 2004-122081 A JP 2004-195370 A JP 2000-325966 A

The object of the present invention is to solve the problem by focusing on the fact that the coagulant with good water drainage is necessary at the initial stage of dehydration as a function of the polymer flocculant necessary for dewatering sludge with a screw press type dehydrator. In addition, we examined what kind of sludge dewatering agent is necessary for sewage mixed raw sludge or sewage digested sludge.

As a result of repeated detailed studies to solve the above problems, the present inventor has reached the following invention. That is, the invention of claim 1 is a sludge dewatering method in which a sludge dewatering agent is added to sewage mixed raw sludge or sewage digested sludge and then dehydrated with a screw press dewatering machine. A sludge dewatering agent for a screw press type dehydrator, characterized in that it is at least one selected from the group of polymer sludge dewatering agents (a), (b) and (c).
Sludge dehydrating agent group;
(A) An amidine-based water-soluble polymer containing 10 to 90 mol% of a structural unit represented by the following formula (1) and / or (2).
(B) 60-100 mol% of a monomer represented by the following general formula (3) and / or (4), 0-30 mol% of a monomer represented by the following general formula (5), water-soluble nonionic A water-soluble polymer having a weight average molecular weight of 1,000,000 to 6,000,000 obtained by polymerizing a monomer mixture comprising 0 to 40 mol% of monomers.







General formula (3)
R3 is hydrogen or a methyl group, R4 and R5 are alkyl groups having 1 to 3 carbon atoms, alkoxy groups or benzyl groups, R6 is hydrogen, an alkyl group having 1 to 3 carbon atoms, alkoxyl groups or benzyl groups. But it ’s okay. A represents an oxygen atom or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X1 represents an anion.
General formula (4)
R7 represents hydrogen or a methyl group, R8 and R9 each represent an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group, and X2 represents an anion.
General formula (5)
R10 is hydrogen or CH2COOY2, Q is SO3, C6H4SO3,
CONHC (CH3) 2CH2SO3, C6H4COO or COO, R11 is hydrogen, methyl group or COOY2, Y1 and Y2 are hydrogen or cation (c) monomers represented by the following general formulas (3) and / or (4) 10 to 70 mol%, charge inclusion rate obtained by polymerizing a monomer mixture consisting of 0 to 30 mol% of a monomer represented by the following general formula (5) and 0 to 90 mol% of a water-soluble nonionic monomer A crosslinkable water-soluble polymer that is 10% or more and 50% or less.
General formula (3)
R3 is hydrogen or a methyl group, R4 and R5 are alkyl groups having 1 to 3 carbon atoms, alkoxy groups or benzyl groups, R6 is hydrogen, an alkyl group having 1 to 3 carbon atoms, alkoxyl groups or benzyl groups. But it ’s okay. A represents an oxygen atom or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X1 represents an anion.
General formula (4)
R7 represents hydrogen or a methyl group, R8 and R9 each represent an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group, and X2 represents an anion.







General formula (5)
R10 is hydrogen or CH2COOY2, Q is SO3, C6H4SO3,
CONHC (CH3) 2CH2SO3, C6H4COO or COO, R11 is hydrogen, a methyl group or COOY2, and Y1 and Y2 each represent hydrogen or a cation.

The invention of claim 2 is characterized in that after adding the sludge dewatering agent of claim 1 to raw sewage mixed sludge or sewage digested sludge, the sludge is dehydrated using a screw press type dehydrator. It is.

The present invention is characterized by at least one selected from the following sludge dehydrating agent groups (a), (b) and (c) when sludge is dehydrated using a screw press type dehydrator. That is, (a) amidine-based water-soluble polymer, (b)
The cationic monomer has a copolymerization rate of 60 to 100 mol%, a weight-average molecular weight of 1 to 6 million cationic or amphoteric water-soluble polymer, and (c) the cationic monomer has a copolymerization rate of unity. It is a water-soluble cross-linkable polymer having a relatively low cross-linking degree, which is composed of 10 to 60 mol% of a monomer and has a charge inclusion ratio of 10% or more and 50% or less, and is made of cationic or amphoteric. In other words, by adding these water-soluble polymers, water-soluble polymers are added to sewage mixed raw sludge and sewage digested sludge to form a tighter and stronger floc. It has filterability and can efficiently perform subsequent operations on pressing and shearing.

Among the water-soluble polymers used in the present invention, the (a) amidine-based water-soluble polymer has the following physical properties and can be produced as follows. That is, in general, a vinyl monomer having a primary amino group or a substituted amino group capable of forming a primary amino group by a conversion reaction, acrylonitrile or methacrylonitrile, and a polymer formed with respect to the total amount of the monomers are water-soluble. The copolymer can be obtained by producing a copolymer to which a crosslinkable monomer is added at a molar ratio to be maintained, and further by reacting a cyano group and a primary amino group in the copolymer to form an amidine. The water-soluble polymer (c) is composed of a vinyl monomer having a primary amino group or a substituted amino group capable of forming a primary amino group by a conversion reaction in the absence of a crosslinkable monomer, acrylonitrile or It can be obtained by copolymerizing acrylonitrile and further amidating.

Examples of the vinyl monomer include N-vinylcarboxylic acid amide, and examples thereof include N-vinylformamide and N-vinylacetamide. In the copolymer, a substituted amino group derived from such a compound is easily converted to a primary amino group by hydrolysis or alcoholysis. Furthermore, this primary amino group reacts with an adjacent cyano group to be amidined. The most common vinyl nitriles to be copolymerized are acrylonitrile.

The polymerization molar ratio of these vinyl monomers and nitriles is usually 20:80 to 80:20, but if desired, a polymerization molar ratio outside this range can be employed. Generally, the higher the ratio of amidine units in the cationic polymer flocculant, the better the performance as the flocculant. Moreover, it is thought that the amine unit has also contributed favorably to the performance as a flocculant. Accordingly, the polymerization molar ratio of vinyl monomer and nitrile that gives a copolymer suitable as a flocculant is generally 20:80 to 80:20, preferably 40:60 to 60:40.

When the N-vinylamide compound represented by the above general formula is used as the vinyl monomer, the amidine reaction is performed by converting the substituted amino group of the copolymer into a primary amino group, and then the generated primary amino group and It can be produced by a two-step reaction in which an amidine structure is formed by reacting with an adjacent cyano group. Preferably, the copolymer is heated in water or an alcohol solution in the presence of a strong acid or a strong base to produce an amidine structure in one step. Even in this case, it is considered that a primary amino group is first generated as an intermediate structure.

Specific conditions for the reaction include, for example, 0.9 to 5.0 times, preferably 1.0 to 3.0 times equivalent of strong acid, preferably hydrochloric acid, relative to the substituted amino group of the copolymer. And a cationized polymer having an amidine unit can be obtained by heating at a temperature of usually 80 to 150 ° C., preferably 90 to 120 ° C., usually for 0.5 to 20 hours. In general, the larger the equivalent ratio of strong acid to substituted amino group and the higher the reaction temperature, the more the amidation proceeds. In addition, in the case of amidine formation, water of usually 10% by weight or more, preferably 20% by weight or more is present in the reaction system with respect to the copolymer used for the reaction.

The water-soluble polymer having the structural unit of the general formula (1) and / or (2) is most typically formed based on N-vinylformamide, acrylonitrile and the total amount of the monomers in accordance with the above description. The resulting polymer is copolymerized by adding a crosslinkable monomer at a molar ratio that maintains water solubility, and the resulting copolymer is usually heated in the presence of hydrochloric acid as an aqueous suspension to be adjacent to the substituted amino group. It is produced by forming an amidine unit from a cyano group. And the amidine-type water-soluble polymer of various compositions can be manufactured by selecting the molar ratio of N-vinylformamide and acrylonitrile to be subjected to copolymerization, and the amidation conditions of the copolymer.

The mol% of the amidine structural unit in the molecule after hydrolysis is 5 to 100 mol%, preferably 10 to 100 mol%, and most preferably 20 to 100 mol%. The nonionic structural unit is an unhydrolyzed carboxylic acid amide group and an unreacted nitrile group, and is 0 to 95 mol%, preferably 0 to 90 mol%, most preferably 0 to 80 mol%. . Moreover, molecular weight is 1 million-10 million as a weight average molecular weight, Preferably it is 2 million-7 million.

The (meth) acrylic water-soluble polymer (b) is highly cationic and is a relatively low molecular weight cationic or amphoteric water-soluble polymer. That is, the weight average molecular weight is 1 million to 6 million, preferably 2 million to 5 million. That is, (b) the monomer represented by the following general formula (3) and / or (4) is 60 to 100 mol%. A water-soluble polymer obtained by polymerizing a monomer mixture composed of 0 to 30 mol% of a monomer represented by the following general formula (5) and 0 to 40 mol% of a water-soluble nonionic monomer.
General formula (3)
R3 is hydrogen or a methyl group, R4 and R5 are alkyl groups having 1 to 3 carbon atoms, alkoxy groups or benzyl groups, R6 is hydrogen, an alkyl group having 1 to 3 carbon atoms, alkoxyl groups or benzyl groups. But it ’s okay. A represents an oxygen atom or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X1 represents an anion.



General formula (4)
R7 represents hydrogen or a methyl group, R8 and R9 each represent an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group, and X2 represents an anion.
General formula (5)
R10 is hydrogen or CH2COOY2, Q is SO3, C6H4SO3,
CONHC (CH3) 2CH2SO3, C6H4COO or COO, R11 is hydrogen, a methyl group or COOY2, and Y1 and Y2 each represent hydrogen or a cation.

Examples of the monomer represented by the general formula (3) and / or (4) include the following. That is, monomers such as dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, and methyl diallylamine are raised, and examples of quaternary ammonium group-containing monomers include those of the above-mentioned tertiary amino-containing monomers. (Meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxy 2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, (meth), which are quaternized products with methyl chloride or benzyl chloride Acryloyloxyethyldimethylbenzylammonium chloride, (meth) acryloyloxy 2-hydroxypropyldimethylbenzylammonium chloride, (meth) acryloylaminopropyldimethylbenzylammonium chloride And the like. Examples of the cationic monomer represented by the general formula (4) include dimethyl diallylammonium chloride and diallylmethylbenzylammonium chloride.

Examples of the anionic monomer represented by the general formula (5) include a sulfone group-containing monomer such as vinyl sulfonic acid, vinyl benzene sulfonic acid, or 2-acrylamido 2-methylpropane sulfonic acid. . 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, N-vinyl pyrrolidone, N -Vinylformamide, N-vinylacetamidoacryloylmorpholine, acryloylpiperazine and the like. Particularly preferred is acrylamide.

The molecular weight of the water-soluble polymer (b) is 2 million to 7 million as a weight average molecular weight, preferably 2 million to 5 million.

The water-soluble polymer (c) is a cross-linkable water-soluble polymer having a relatively low degree of cross-linking. In the present invention, the degree of crosslinking, which is the charge inclusion rate, is defined. That is, in the case of a cationic crosslinkable water-soluble ionic polymer and a crosslinkable water-soluble ionic polymer that is amphoteric and has a positive difference in molar concentration between a cationic monomer and an anionic monomer, Is calculated as follows.
Charge inclusion rate [%] = (1−α / β) × 100
α is a 0.01% aqueous solution of a crosslinkable water-soluble ionic polymer adjusted to pH 4.0 with acetic acid by a PCD titration apparatus (M &uuml; tek PCD 03, M &uuml; tek PCD-Two Titortor Version 2) manufactured by Mutec. Dropping solution: 1/1000 N aqueous polyvinyl sulfonate solution, dropping rate: 0.05 ml / 10 sec, end point determination: 0 mV. Titration determined by titration. β is added to a 0.01% aqueous solution of a crosslinkable water-soluble ionic polymer adjusted to pH 4.0 with acetic acid in an amount sufficient to neutralize the charge with a 1 / 400N aqueous potassium polyvinyl sulfonate solution, and sufficiently stirred. Similarly, titrate with a PCD titrator at a drop solution: 1 / 1000N diallyldimethylammonium chloride aqueous solution, drop rate: 0.05 ml / 10 sec, end point determination: 0 mV, and subtract this titration value from the blank value. . The blank value is the same as the sample adjusted to pH 4.0 with acetic acid, and the same concentration of potassium polyvinyl sulfonate aqueous solution is similarly added by a PCD titration apparatus. Dropping solution: 1 / 1000N diallyldimethylammonium chloride aqueous solution, dropping rate: 0.05 ml / 10 sec, end point determination: titration obtained by titration at 0 mv.

In the present invention, in a crosslinkable water-soluble polymer that is amphoteric and has a negative difference in molar concentration between a cationic monomer and an anionic monomer, the charge inclusion rate is calculated as follows.
Charge inclusion rate [%] = (1−α / β) × 100
α is a 0.01% aqueous solution of a cross-linkable water-soluble ionic polymer adjusted to pH 10.0 with ammonia using a PCD titration apparatus (M &uuml; tek PCD 03, M &uuml; tek PCD-Two Titortor Version 2) manufactured by Mutek. Dropping solution: 1 / 1000N diallyldimethylammonium chloride aqueous solution, dropping rate: 0.05 ml / 10 sec, end point determination: 0 mV. Titration determined by titration. β is added to a 0.01% aqueous solution of a crosslinkable ionic water-soluble polymer adjusted to pH 10.0 with ammonia, and an aqueous solution of 1 / 400N diallyldimethylammonium chloride is added in an amount sufficient for charge neutralization, and sufficiently stirred. In the same manner, titrate with a PCD titrator at a dropping solution of 1 / 1000N potassium polyvinylsulfonate aqueous solution, dropping rate: 0.05 ml / 10 sec, end point determination: 0 mV, and subtract this titration from the blank value. . The blank value is a diallyldimethylammonium chloride aqueous solution having the same concentration as that of the above sample adjusted to pH 10.0 with ammonia in the same manner by using a PCD titration apparatus. Dropping solution: 1/1000 N aqueous potassium polyvinylsulfonate solution, dropping rate: 0.05 ml / 10 sec, end point determination: titration obtained by titration at 0 mv.

When the crosslinkable ionic water-soluble polymer is used, the water-soluble polymer of the present invention preferably has a charge encapsulation rate of 5% or more and 50% or less. If the charge inclusion rate is less than 5%, the sewage mixed raw sludge or the sewage digested sludge has low crosslinkability and is suitable for the purpose of the present invention, which requires cohesiveness with good drainage in the initial stage of dehydration. Absent. On the other hand, if the charge inclusion rate is 50% or more, the amount of addition is increased due to excessive progress of crosslinking, leading to an increase in cost, which is disadvantageous.

When these crosslinkable water-soluble polymers are cationic, they are 10 to 70 mol% of the monomer represented by the general formula (3) and / or (4), and water-soluble nonionic monomers 0 to 90. A monomer mixture consisting of mol% and a crosslinkable monomer are added and polymerized. In the case of amphoteric, the anionic monomer represented by the general formula (5) is allowed to coexist in the cationic monomer and the crosslinkable monomer for polymerization. Furthermore, the anionic crosslinkable water-soluble polymer is obtained by adding a crosslinkable monomer to a monomer or a monomer mixture comprising the anionic monomer represented by the general formula (5) and a nonionic monomer. Add and polymerize. The ratio of the crosslinkable monomer to all the monomers is 0.00001 to 0.002 mol%. The molecular weight of these crosslinkable water-soluble polymers is 3 million to 15 million in weight average molecular weight, more preferably 5 million to 10 million.

The reason why the crosslinkable water-soluble polymer (c) having a relatively low degree of crosslinking can be preferably applied to raw sewage mixed sludge or sewage digested sludge is considered as follows. That is, the water-soluble polymer is inhibited from spreading 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. When a polymer flocculant is used as the sludge dewatering agent, the above-mentioned “density packed” molecular form is considered efficient. 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. As a result, it is considered that during mechanical dehydration, water drainage is good and the moisture content of the cake is reduced. Furthermore, if the polymer flocculant used is amphoteric, it may depend on ionic bonds between the molecules of the polymer flocculant, or between the cationic groups and anionic groups of the polymer flocculant molecules adsorbed on the surface of the suspended particles. Ionic bonds also occur and charge neutralization occurs. That is, it approaches a state close to zero in terms of charge. Therefore, the optimum addition amount range is widened, and the drug injection can be easily adjusted. Even when the ionicity of the polymer flocculant is cationic, adsorption, aggregation, etc. are presumed to occur by the same mechanism, but charge neutralization by ionic bond between the cationic group and anionic group is Since it does not occur, re-dispersing action tends to occur if it is added too much, and the optimum addition amount range becomes narrower than that of both amphoteric.

When the above concept is applied to a dehydration mechanism using a screw press type dehydrator, the following is considered. In this dehydrator, the sludge in which flocculant is added and flocculent flocs are generated is introduced into the inside of a cylindrical strainer (filter cylinder) composed of a perforated punching plate, a slit-shaped wedge wire, etc. This is a type in which it is squeezed and dehydrated while being conveyed by a specially shaped screw shaft that rotates at an extremely low speed of 2.0 rpm. Therefore, when dehydrating with a screw press dehydrator, the floc diameter is larger than the strainer hole or slit width, and the coagulated sludge is transported, squeezed and twisted by the screw for a long time. That is required. Therefore, strainer holes and slit filterability of sludge floc in the initial filtration process are considered to be important factors that determine the treatment state. Therefore, the addition of a crosslinkable water-soluble polymer to form a tighter and stronger floc has a rapid filterability in the initial filtration step, and efficiently performs subsequent pressing and shearing operations. It is possible. The fact that a high-strength floc is formed means that the water block that should be dewatered without squeezing or shearing is secured and the dewatering action is performed efficiently. To do. As a result, the water content of the dehydrated cake is estimated to be lower than that of conventional water-soluble polymers.

Since it has a mechanism of being dehydrated by filtration, pressing, and shearing, it is basically preferable to have some fibers, so in the case of sewage digested sludge, a crosslinkable water-soluble polymer is suitable. In the case of sewage mixed raw sludge, since it has a relatively large amount of fibers, it can be applied to dehydration even if the degree of crosslinking is low.

In addition, the copolymerization ratio of the amidine-based water-soluble polymer (a) and (b) the cationic monomer is 60 to 100 mol%, and the cationic or amphoteric water-soluble polymer having a relatively low weight average molecular weight. The reason why the molecule can be applied to the screw press type dehydrator is considered to be because it is suitable for the point that cohesion with good water drainage is necessary in the early stage of dehydration. Both types of water-soluble polymers (a) and (b) have a low molecular weight, and the process of diffusing, adsorbing and agglomerating into sludge is fast, and it is necessary to achieve a cohesiveness with good drainage at the initial stage of dehydration. The condition is met.

Here, sewage mixed raw sludge is called sludge that is generated when sewage is collected and settled in the primary sedimentation tank, that is, raw sludge, and the supernatant of the primary sedimentation tank is treated after biological treatment in an aerating tank. When the suspension in water is settled and returned to the aerating tank, excess sludge is sludge generated to remove it from the treatment system, that is, excess sludge, which is a mixture of these sludges. . Sewage digested sludge refers to sludge generated when raw sludge is subjected to anaerobic fermentation. The addition amount of the sludge dehydrating agent used in the present invention is 0.1 to 1.5% by mass with respect to the sludge solid content, and preferably 0.2 to 1.0%.

Hereinafter, the present invention will be described specifically by way of examples. However, the present invention is not limited to the following examples.

(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, 35.0 g of deionized water and 19.7 g of a 60% aqueous solution of acrylic acid (abbreviated as AAC) were mixed and neutralized with 17.8 g of a 35% aqueous sodium hydroxide solution. After neutralization, 119.1 g of 80% aqueous solution of acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), 42.6 g of 80% aqueous solution of methacryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMC), and acrylamide (abbreviated as AAM) 116.4 g of 50% aqueous solution and 3.3 g of methylenebisacrylamide 0.1% by mass aqueous solution (0.0018 mol% to 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 DMC / DMQ / AAC / AAM = 10/30/10/50 (mol%).

After adding 2.0 g of isopropyl alcohol 40% aqueous solution (0.5% by mass 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 mass with respect to 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 polymerization, 10.0 g of polyoxyethylene tridecyl ether (2.0% by mass 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). . The charge inclusion rate of the obtained sample was measured by a PCD titration apparatus manufactured by Mutech, and the weight average molecular weight was measured by a molecular weight measuring device (DLS-7000 manufactured by Otsuka Electronics Co., Ltd.) by a static light scattering method. The charged 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 of DMC / DMQ / AAM = 20/40/40 (mol%) was polymerized by the same procedure as in Synthesis Example 1, and a sample was added with a phase inversion agent. 2. The charged composition is shown in Table 1, and the results are shown in Table 2.

(Synthesis Example 3) A water-in-oil emulsion having a monomer composition of DMC / DMQ / AAC / AAM = 30/40/10/20 (mol%) was polymerized by the same operation as in Synthesis Example 1, and a phase inversion agent was obtained. To make Sample-3. The charged composition is shown in Table 1, and the results are shown in Table 2.

(Synthesis Example 4) In a 500 mL four-necked flask equipped with a thermometer, a stirrer, a nitrogen introduction tube, a monomer supply pipe connected to a peristaltic pump (SMP-21 type, manufactured by Tokyo Rika Kikai Co., Ltd.) and a condenser, N- A monomer solution in which 57.3 g of vinylformamide, 42.7 g of acrylonitrile (molar ratio of the monomer is 50:50), 87.2 g of deionized water, and Isopar M (trade name, manufactured by Esso, high-boiling kerosene) 100 g , 2 g of Hypermer B-246 (trade name, manufactured by ICI, higher fatty acid ester) and 6.5 g of sorbitan monooleate are weighed and deoxygenated by introducing nitrogen gas. Thereafter, while stirring at a temperature of 52 ° C. and a rotation speed of 500 rpm, azo polymerization initiator [2,2′-azobis (2,4-dimethylvaleronitrile)] was added at 2500 ppm based on the total monomer weight, and then 60 ° C. The polymerization was carried out while maintaining the temperature for 18 hours.

After cooling the polymer to room temperature, a stabilizer was added to absorb 29.3 g of anhydrous hydrogen chloride, followed by hydrolysis at 85 ° C. for 24 hours. The obtained polymer emulsion was added to acetone to cause precipitation, and this was vacuum dried to obtain a solid polymer. The composition of the polymer after amidine formation thus obtained was calculated from the integrated value of the absorption peak corresponding to each repeating unit in the polymer of the ¹³ C-NMR spectrum. As a result, it was found that the amidine structural unit was 81 mol%, the primary amino group structural unit was 6 mol%, and the other structural units were 13 mol%. This is designated as Sample-4. The charged composition is shown in Table 1, and the results are shown in Table 2.

(Synthesis Example 5) A water-in-oil emulsion having a monomer composition NVF / AN = 60/40 (mol%) was polymerized in the same manner as in Synthesis Example 4, and after polymerization, hydrolyzed and amidined with hydrochloric acid. A phase inversion agent was added to make Sample-5. As a result, it was found that the amidine structural unit was 71 mol%, the primary amino group structural unit was 15 mol%, and the other structural units were 14 mol%. The charged composition is shown in Table 1, and the results are shown in Table 2.

(Synthesis Example 6) A water-in-oil emulsion having a monomer composition DMQ / AAM = 60/40 (mol%) was polymerized in the same manner as in Synthesis Example 1, and a phase inversion agent was added to prepare Sample-6. The charged composition is shown in Table 1, and the results are shown in Table 2.

(Synthesis Example 7) A water-in-oil emulsion having a monomer composition of DMC / DMQ / AAC / AAM = 40/30/10/20 (mol%) was polymerized by the same operation as in Synthesis Example 1, and a phase inversion agent was obtained. Was added to make Sample-7. The charged composition is shown in Table 1, and the results are shown in Table 2.

(Synthesis Example 8) A water-in-oil emulsion having a monomer composition of DMC / DMQ / AAC / AAM = 20/60/5/15 (mol%) was polymerized in the same manner as in Synthesis Example 1, and a phase inversion agent was obtained. Was added to make Sample-8. The charged composition is shown in Table 1, and the results are shown in Table 2.

(Comparative Synthesis Example 1) A water-in-oil emulsion having a monomer composition DMQ / AAM = 30/70 (mol%) was polymerized by the same operation as in Synthesis Example 1, and a phase inversion agent was added to make Comparative-1. . The charged composition is shown in Table 1, and the results are shown in Table 2.

(Comparative Synthesis Example 2) A water-in-oil emulsion having a monomer composition of DMC / DMQ / AAC / AAM = 10/30/10/50 (mol%) was polymerized by the same operation as in Synthesis Example 1, and phase inversion was performed. Comparative agent-2 was added. The charged composition is shown in Table 1, and the results are shown in Table 2.

(Comparative Synthesis Example 3) A water-in-oil emulsion having a monomer composition DMQ / AAM = 60/40 (mol%) was polymerized in the same manner as in Synthesis Example 1, and a phase inversion agent was added to make Comparative-1. . The charged composition is shown in Table 1, and the results are shown in Table 2.

(Comparative Synthesis Example 4) A water-in-oil emulsion having a monomer composition of DMC / DMQ / AAC / AAM = 30/40/10/20 (mol%) was polymerized by the same operation as in Synthesis Example 1, and phase inversion was performed. Comparative agent-2 was added. The charged composition is shown in Table 1, and the results are shown in Table 2.

(Table 1) Composition
DMC: methacryloyloxyethyltrimethylammonium chloride DMQ: acryloyloxyethyltrimethylammonium chloride, AAC: acrylic acid, AAM: acrylamide, cross-linking agent addition amount: mol% to monomer, MBA; methylenebisacrylamide, AN: acrylonitrile, NVF : N-vinylformamide

(Table 2) Manufacturing results
Dispersion viscosity: mPa · s, molecular weight: 10,000, charge inclusion rate:%

200 mL of mixed sludge of sewage surplus sludge and raw sludge (pH 6.71, total SS content 36400 mg / L) was collected in a poly-bicker, and sample-1 to sample-3 (crosslinkable water-soluble polymer) in Table 2; Sample-4 to sample-5 (polyamidine) and sample-6 to sample-8 (low molecular weight high cationic water-soluble polymer) were added to 0.6% solids sludge, and the beaker was transferred and stirred 20 times. After performing, it filtered with the T-1179L filter cloth (product made from nylon), the measurement of the amount of filtrates 10 seconds later, and the floc intensity | strength (size) were measured visually. Thereafter, the sludge filtered for 50 seconds was dehydrated at a press pressure of 3 kg / m ² for 1 minute, and then the moisture content of the cake (dried at 105 ° C. for 20 hours) was measured. The results are shown in Table 3.

(Comparative Test 1) Using Comparison-1 and Comparison-2 (non-crosslinkable water-soluble ionic polymer) and Sample-3 and Sample-4 (high cationic water-soluble polymer having a high molecular weight) in Table 2, The same test operation as in Example 1 was performed. The results are shown in Table 3.

(Table 3)
Ten seconds later, filtrate amount: ml, cake moisture content: mass%
Filter cloth peelability: Good in the order of ◯>Δ> ×.

200 mL of sewage digested sludge (pH 7.73, total SS content 26000 mg / L) was collected in a poly-bicker, and sample-1 to sample-3 (crosslinkable water-soluble polymer) in Table 2 and sample-4 to sample- 5 (polyamidine) and Sample-6 to Sample-8 (low molecular weight, high cationic water-soluble polymer) were added to 0.40% of the solid content of the sludge, and after the beaker was transferred and stirred 20 times, T- The solution was filtered through a 1179 L filter cloth (made of nylon), and the amount of filtrate after 10 seconds and the floc strength (size) were measured visually. Thereafter, the sludge filtered for 50 seconds was dehydrated at a press pressure of 3 kg / m ² for 1 minute, and then the moisture content of the cake (dried at 105 ° C. for 20 hours) was measured. The results are shown in Table 4.

(Comparison Test 2) Using Comparison-1 and Comparison-2 (non-crosslinkable water-soluble ionic polymer) and Sample-3 and Sample-4 (high cationic water-soluble polymer having a high molecular weight) in Table 2, The same test operation as in Example 1 was performed. The results are shown in Table 4.

(Table 4)
Ten seconds later, filtrate amount: ml, cake moisture content: mass%
Filter cloth peelability: Good in the order of ◯>Δ> ×.

Claims (2)

In a sludge dewatering method in which a sludge dewatering agent is added to sewage mixed raw sludge or sewage digested sludge and then dehydrated with a screw press type dewatering machine, the polymer sludge dewatering agent comprises the following polymer sludge dewatering agent group (a A sludge dewatering agent for a screw press type dehydrator, which is at least one selected from the group consisting of (b) and (c).
Sludge dehydrating agent group;
(A) An amidine-based water-soluble polymer containing 10 to 90 mol% of a structural unit represented by the following formula (1) and / or (2).
(B) 60-100 mol% of a monomer represented by the following general formula (3) and / or (4), 0-30 mol% of a monomer represented by the following general formula (5), water-soluble nonionic A water-soluble polymer having a weight average molecular weight of 1,000,000 to 6,000,000 obtained by polymerizing a monomer mixture comprising 0 to 40 mol% of monomers.
General formula (3)
R3 is hydrogen or a methyl group, R4 and R5 are an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, R6 is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group. But it ’s okay. A represents an oxygen atom or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X1 represents an anion.
General formula (4)
R7 represents hydrogen or a methyl group, R8 and R9 each represent an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X2 represents an anion.
General formula (5)
R10 is hydrogen or CH2COOY2, Q is SO3, C6H4SO3,
CONHC (CH3) 2CH2SO3, C6H4COO or COO, R11 is hydrogen, a methyl group or COOY2, and Y1 and Y2 each represent hydrogen or a cation.
(C) 10 to 70 mol% of a monomer represented by the following general formula (3) and / or (4), 0 to 30 mol% of a monomer represented by the following general formula (5), water-soluble nonionic A crosslinkable water-soluble polymer having a charge inclusion ratio of 10% to 50% obtained by polymerizing a monomer mixture composed of 0 to 90 mol% of monomers.



General formula (3)
R3 is hydrogen or a methyl group, R4 and R5 are alkyl groups having 1 to 3 carbon atoms, alkoxyl groups or benzyl groups, and R6 is hydrogen, an alkyl group having 1 to 3 carbon atoms, alkoxyl groups or benzyl groups. But it ’s okay. A represents an oxygen atom or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X1 represents an anion.
General formula (4)
R7 represents hydrogen or a methyl group, R8 and R9 each represent an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group, and X2 represents an anion.
General formula (5)
R10 is hydrogen or CH2COOY2, Q is SO3, C6H4SO3,
CONHC (CH3) 2CH2SO3, C6H4COO or COO, R11 is hydrogen, a methyl group or COOY2, and Y1 and Y2 each represent hydrogen or a cation. A sludge dewatering method, comprising: adding a sludge dewatering agent according to claim 1 to raw sewage mixed sludge or sewage digested sludge, and then dewatering the sludge using a screw press type dehydrator.