JPH05192513A - Cationic polymeric flocculant - Google Patents

Abstract

PURPOSE:To still more enhance the capacities related to dehydration properties, filterability and storage stability as a flocculant by using a polymeric flocculant containing a plurality of specific repeating units in a specific ratio and set to a specific value in its reduced viscosity measured as a solution with a specific concn. within a 1N saline solution at a specific temp. CONSTITUTION:A cationic polymeric flocculant has an amidine structure containing 20-90mol% of a repeating unit (amidine unit) represented by formula I and/or formula II, 0-2mol% of a repeating unit (substituted amino group unit) represented by formula III, 0-70mol% of a repeating unit (cyano unit) represented by formula IV and 0-70mol% of a repeating unit (amino group unit) represented by formula V and the value of reduced viscosity thereof measured as a 0.1 g/dl solution within a 1N saline solution at 25 deg.C is 0.1-10dl/g. In the formulae I-V, R<1> and R<2> are a hydrogen atom or a methyl group, R<3> is a l-4C alkyl group or a hydrogen atom and X is an anion.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a cationic polymer flocculant. Specifically, it relates to a cationic polymer flocculant having an amidine structural unit.

[0002]

2. Description of the Related Art Cationic polymers are used for applications such as flocculants and paper chemicals. BACKGROUND ART Heretofore, polymers of metal salts or ammonium salts of dialkylaminoalkyl (meth) acrylate, Hoffmann decomposition reaction products of Mannich polyacrylamide, Mannich reaction products, and the like have been known. Further, in recent years, as a cationic polymer, polyvinylamine partially modified with a homopolymer or copolymer of N-vinylformamide has been proposed (US Pat. Nos. 4,421,602 and 4,774,743). No. 285, No. 4,957,977).

[0003]

However, in the conventional cationic polymer, the function in each application, for example,
The dehydrating property, filterability, storage stability and the like of the flocculant are still insufficient, and further improvement in performance has been desired.

[0004]

Means for Solving the Problems As a result of intensive investigations by the present inventors in view of the above problems, a specific cationic polymer having an amidine structure was found to be extremely effective as a flocculant, particularly as a flocculant for organic sludge. The inventors have found that they have excellent performance and arrived at the present invention. That is, the most representative of the cationic polymer flocculants according to the present invention is a repeating unit (amidine unit) represented by the following (1) and / or (2) in an amount of 20 to 90 mol% and (3). 0 to 2 mol% of the represented repeating unit (substituted amino group unit), (4)
The repeating unit (cyano group unit) represented by
%, Containing 0 to 70 mol% of the repeating unit (amino group unit) represented by (5), and 0.1% in 1N saline solution.
As a solution of g / dl, the value of the reduced viscosity measured at 25 ° C. is 0.1 to 10 dl / g.

[0005]

[Chemical 7]

(Wherein R ¹ and R ² represent a hydrogen atom or a methyl group, R ³ represents an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and X ⁻ represents an anion). 2)
The amidine unit represented by has an amidine structure consisting of a 5-membered ring, and is generally equivalently observed in analyzes such as nuclear magnetic resonance spectroscopy (NMR) and infrared spectroscopy (IR). , (1) and (2). However, as shown in the conceptual diagram below, two types of repeating units represented by (1) and (2) must be taken into consideration when considering the repeating units of the polymer produced in the amidation reaction of the polymer described later. I have to. In the conceptual diagram below, (4) and (5) represent cyano group units and amino group units that were not involved in the amidination reaction.

[0007]

[Chemical 8]

The method for producing the above-mentioned cationic polymer having an amidine structure is not particularly limited, but in general, ethylene having a primary amino group or a substituted amino group capable of forming a primary amino group by a conversion reaction is used. It can be obtained by producing a copolymer of a polymerizable unsaturated monomer and a nitrile of acrylonitrile or methacrylonitrile, and further reacting a cyano group and a primary amino group in the copolymer to form an amidine.

The above-mentioned ethylenically unsaturated monomers include those represented by the general formula CH ₂ ═CR ² —NHCOR ³ (wherein R ² is a hydrogen atom or a methyl group, R ³ is an alkyl group having 1 to 4 carbon atoms or hydrogen). Compounds represented by the formula (A) are preferred. In the copolymer, the substituted amino group derived from such a compound is easily converted into a primary amino group by hydrolysis or alcoholysis. Furthermore, this primary amino group reacts with an adjacent cyano group to form an amidine. As the compound, N- vinylformamide ^{(= R 2 = H, R} 3 H), N- vinylacetamide ^{(R 2 = H, R 3} = Me) and the like.

The polymerization molar ratio of these ethylenically unsaturated monomers and nitriles is usually from 20:80 to 80:20.
However, if desired, it is also possible to employ a polymerization molar ratio outside this range, for example, a polymerization molar ratio in which the ratio of the ethylenically unsaturated monomer is larger. Generally, the larger the proportion of amidine units in the cationic polymer flocculant, the better the performance as a flocculant. Further, it is considered that the amine unit also contributes favorably to the performance as the aggregating agent. Therefore, the polymerization molar ratio of the ethylenically unsaturated monomer and the nitrile that gives a copolymer suitable as a flocculant is
Generally 20:80 to 80:20, especially 40:60 to 6
It is 0:40.

As a method for copolymerizing the ethylenically unsaturated monomer and the nitriles, a usual radical polymerization method is used, and any of bulk polymerization, aqueous solution precipitation polymerization, suspension polymerization, emulsion polymerization and the like can be used. .. When the polymerization is carried out in a solvent, the raw material monomer concentration is usually 5 to 80% by weight, preferably 20 to 60% by weight. Although a general radical polymerization initiator can be used as the polymerization initiator, an azo compound is preferable, and a hydrochloride of 2,2′-azobis-2-amidinopropane and the like are exemplified. Further, the polymerization reaction is generally carried out at a temperature of 30 to 100 ° C. under an inert gas stream. The obtained copolymer can be used as it is or after being diluted, that is, can be subjected to the amidation reaction in the form of a solution or suspension, and can be desolvated and dried by a known method to give a copolymer. After being separated as a solid, it can also be subjected to an amidination reaction in a solid state.

In the amidation reaction, when the N-vinylamide compound represented by the above general formula is used as the ethylenically unsaturated monomer, the substituted amino group of the copolymer is converted into a primary amino group and then produced. The cationic polymer flocculant according to the present invention can be produced by a two-step reaction of reacting a primary amino group with a cyano group adjacent thereto to form an amidine structure. Then, preferably, the copolymer is heated in a water or alcohol solution in the presence of a strong acid or a strong base to form an amidine structure in one step. Also in this case, first, it is considered that the primary amino group is generated as an intermediate structure.

The specific conditions of the reaction are, for example, usually 0.9 to 0.9 with respect to the substituted amino group of the copolymer.
A 5.0-fold, preferably 1.0-3.0-fold equivalent of a strong acid, preferably hydrochloric acid is added, and the mixture is heated at a temperature of usually 80 to 150 ° C, preferably 90 to 120 ° C, usually for 0.5 to 20 hours. As a result, a cationized polymer having an amidine unit can be obtained. In general, the larger the equivalent ratio of the strong acid to the substituted amino group and the higher the reaction temperature, the more the amidination proceeds. In addition, upon amidation, 10% by weight or more, preferably 20% by weight or more of water is usually present in the reaction system with respect to the copolymer used in the reaction.

The aggregating agent comprising a cationic polymer according to the present invention is most typically prepared by copolymerizing N-vinylformamide and acrylonitrile according to the above-mentioned explanation, and the resulting copolymer is usually prepared. It is prepared by heating as an aqueous suspension in the presence of hydrochloric acid to form an amidine unit from a cyano group adjacent to a substituted amino group. Then, by selecting the molar ratio of N-vinylformamide and acrylonitrile to be subjected to the copolymerization and the amidination conditions of the copolymer, it is possible to produce a flocculant composed of a cationic polymer having various compositions.

One of the representative examples of the flocculant comprising a cationic polymer according to the present invention is 20 to 90 mol% of the repeating unit represented by the above (1) and / or (2), and the above (3). 0 to 2 mol% of the repeating unit represented by, 0 to 70 mol% of the repeating unit represented by (4), and 0% of the repeating unit represented by (5).
It contains 70 mol% and has a reduced viscosity of 0.1 to 10 dl / g. In addition, in this specification, the reduced viscosity shall be measured at 25 ° C. as a solution of 0.1 g / dl in 1 N saline. In the above-mentioned aggregating agent, it is considered that the amidine unit largely contributes to the performance as an aggregating agent.

The larger the proportion of amidine units, the more the performance as a flocculant tends to generally improve. But,
It is difficult to produce a copolymer having an amidine unit content of more than 90 mol% by heating the above copolymer in an aqueous hydrochloric acid solution. Therefore, the proportion of amidine units in the flocculant is usually preferably 30 to 85 mol%. Further, from the viewpoint of ease of production and the performance of the obtained coagulant, a coagulant having an amidine unit ratio of 50 to 80 mol% is generally most preferable. For example, a flocculant containing 50 to 80 mol% of amidine units and 0 to 2 mol% of substituted amino group units, and having a total of 97 to 100 mol% of amidine units, cyano group units and amino group units, One of the best.

The repeating unit (3) is derived from an N-vinylamide compound which is more expensive than acrylonitrile, but its presence does not seem to contribute to the performance as a flocculant. Therefore, in general, the repeating unit (3)
Should have a content of 0 to 2 mol%, preferably 0 to 1 mol%. When the number of repeating units (3) increases, the dehydrating performance and storage stability of the coagulant may deteriorate. However, when the proportion of amidine units is 50 mol% or more, the coagulant has excellent performance even if a large amount of repeating units (3) are present. Examples of such aggregating agent include an amidine unit of 50 to 80 mol%, a repeating unit (3) of 2 to 20 mol%, and a repeating unit (4) of 0 to 4
8 mol% and the repeating unit (5) are 0 to 48 mol%, and the total of the repeating units (1) to (5) is 90 mol% or more, preferably 97 mol% or more. In order to produce a coagulant having a large number of repeating units (3), a copolymer of N-vinylformamide and a nitrile is added with an equivalent amount or less of a strong acid with respect to a substituted amino group in the copolymer, In addition, the amount of water present in the reaction system may be set to 20% by weight or less with respect to the copolymer and heated. Since the resulting cationic polymer flocculant generally has poor storage stability as it is, a strong acid is added to completely neutralize the cationic units of repeating units (1), (2) and (5). Preferably.

The effect of the repeating unit (4) on the performance as a flocculant is not clear, but it is considered that there is at least no adverse effect. The repeating unit (4) is 0 to 7 in the flocculant.
Although 0 mol% is present, since nitrile is an inexpensive monomer, the presence of the repeating unit (4) is effective in reducing the production cost of the coagulant and improving the performance advantage with respect to the cost. A suitable abundance ratio of the repeating unit (4) is 5 to 60 mol%, particularly 5 to 50 mol%.

In the flocculant according to the present invention, the molar ratio of the repeating unit (4) to the amidine unit [(1) + (2) /
(4)] is generally in the range of 0.5 to 10.0. Preferably, this molar ratio should be in the range 2.0 to 5.0. The reason is that the larger the number of amidine units, the better the performance as a coagulant in general. The repeating unit (5) is cationic and is considered to contribute effectively to the performance as a flocculant like the amidine unit. The repeating unit (5) is present in the flocculant in an amount of 0 to 70 mol%, preferably 5 to 60 mol%,
Both (2) and (5) are derived from the repeating unit (3). Therefore, generally speaking, as many repeating units (3) as possible are repeated units (1),
It is preferably converted to (2) or (5). Repeating units (1), (2) and (5) in the flocculant
Is generally 40 mol% or more, preferably 60 to 95
Mol%. This means that, among the repeating units constituting the aggregating agent, the majority of the repeating units are considered to contribute favorably to the aggregating performance. The molar ratio [(1) + (2) / (5)] of the repeating unit (5) and the amidine unit in the flocculant according to the present invention is generally in the range of 0.5 to 10.0. The amidine unit is considered to contribute more effectively to the performance of the aggregating agent than the repeating unit (5), so that [(1) + (2) / (5)] is in the range of 2.0 to 5.0. Is more preferable. As described above, the formation of the amidine structure is caused by the reaction between the adjacent repeating unit (4) and the repeating unit (3) (or the repeating unit (5) produced therefrom). Some remain. Therefore, one of the preferable coagulants according to the present invention is that the total of the repeating units (1), (2) and (5) is 70 to 90 mol%.
And the total amount of repeating units (1), (2), (4) and (5) is 90 mol% or more, preferably 97 mol% or more.

The aggregating agent according to the present invention may further contain other repeating units in addition to the above-mentioned repeating units. However, the total of the above-mentioned repeating units (1) to (5) should occupy 90 mol% or more, preferably 95 mol% or more. Other repeating units that can be usually contained in the aggregating agent according to the present invention include the following (6) to (9).

[0021]

[Chemical 9]

(In the formula, R ¹ and R ² represent a hydrogen atom or a methyl group, and M ⁺ represents a cation.) Repeating unit (6)
And (7) are produced by hydrolysis of the repeating unit (4). That is, when a copolymer of a nitrile and an N-vinylamide compound is heated in the presence of a strong acid and water to form an amidine structure, a part of the cyano group in the copolymer is similarly hydrolyzed and repeated. An amide group of the unit (6) and a carboxyl group of the repeating unit (7) are produced.

It is unclear how the repeating unit (6) (amide group unit) affects the performance as a flocculant, but it is generally considered that the smaller the repeating unit (6) is, the more preferable. Therefore, the ratio of the repeating unit (6) in the flocculant is usually in the range of 0 to 5 mol%, preferably 0 to 2 mol%.

The repeating unit (7) (carboxyl group unit) is an anionic repeating unit and may adversely affect the performance of the aggregating agent. Therefore, it is preferable that the ratio is small. The proportion of the repeating unit (7) in the flocculant is usually 0 to 5 mol%, preferably 0 to 2 mol%. Repeating units (8) and / or (9) (lactam units) are presumed to be formed from repeating units (5) and (6). The effect of this on the performance of the flocculant is unknown, but its proportion is generally 0-5 mol%, especially 0-2.
It is in the range of mol%.

The reduced viscosity of the aggregating agent comprising the cationic polymer according to the present invention is usually 0.1 to 10 dl as described above.
/ G, preferably in the range of 1-8 dl / g. The flocculant according to the present invention is used for flocculating and removing suspended matter therein from various kinds of waste water. In particular, this is extremely effective for organic sludge. For example, in a municipal sewage treatment plant, first sludge sludge settled from sewage, excess sludge settled from runoff water from an activated sludge tank or a mixture thereof (the mixture is usually referred to as "mixed raw sludge"), Furthermore, when this coagulant is added to digested sludge generated when anaerobic fermentation treatment of activated sludge is performed, strong flocs are formed. When this floc is treated with a press dehydrator such as a belt press, a screw press or a filter press, or a pressure dehydrator such as a centrifuge or a vacuum filter, dehydration can be performed at a remarkably large dehydration rate, and a low water content A rate slag is obtained. As organic sludge, in addition to those generated at urban sewage treatment plants, sludge generated when treating human waste as activated sludge, sludge generated when anaerobic fermentation treatment of human waste and activated sludge, and other than urban sewage The sludge and the like generated when the various industrial wastewaters are treated with activated sludge can be advantageously treated.

The coagulant is added to the slurry containing sludge in an amount of usually 0.01 to 3.0% by weight, preferably 0.1 to 1.0% by weight, based on the solid content of the slurry. To do. The pH of the slurry containing sludge is 3.5 to 8.0.
Is preferred. When this flocculant is added to the slurry having a pH of 4.5 to 7.5, a particularly excellent flocculating effect is exhibited.

[0027]

EXAMPLES The present invention will now be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the examples, “%” means “% by weight” unless otherwise specified.

Examples 1 to 5 [Production method of flocculant] Acrylonitrile containing acrylonitrile in a mole fraction shown in Table 1 in a 50 ml four-necked flask equipped with a stirrer, a nitrogen introducing tube and a cooling tube. And N
-6.0 g and 34.0 of a mixture of vinylformamide.
g of demineralized water was added. 60 with stirring in a nitrogen gas stream
After heating to ℃, 10% 2,2'-azobis-2-
0.12 g of amidinopropane dihydrochloride aqueous solution was added. After stirring and holding at 45 ° C. for 4 hours, the temperature was raised to 60 ° C. and further holding for 3 hours to obtain a suspension in which the polymer was precipitated in water. 20 g of water was added to the suspension, and then 2 equivalents of concentrated hydrochloric acid was added to the formyl group in the polymer, and the mixture was kept at 100 ° C. for 4 hours while stirring to polymerize the polymer. The resulting polymer solution was added to acetone to cause precipitation, which was vacuum dried to obtain solid polymers A to E.

Compositions and reduced viscosities of the polymers A to E were measured by the following methods. The results are shown in Table-1.

[Method of Analyzing Composition] The composition of each raw material polymer before the amidination was determined by ¹³ C-NMR spectrum ( ¹³ C-
It was calculated from the integrated value of the absorption peak corresponding to each monomer unit of the magnetic resonance spectrum). The composition of each of the polymers A to E after amidation was calculated from the integrated value of the absorption peak corresponding to each repeating unit of the ¹³ C-NMR spectrum. The repeating units (1) and (2) are not distinguished,
It was calculated as the total amount. The repeating units (8) and (9) were also determined as the total amount without distinction.

Further, repeating units (1) and (2),
The absorption peaks of (6) and (8) and (9) are 170 to 18
Since it is found in a very close position around 5 ppm,
The structure corresponding to each absorption peak was assigned by the following method. That is, the weight balance was confirmed by the elemental analysis of the polymer and the measurement of the water content, and further the IR spectrum was measured in addition to the ¹³ C-NMR spectrum of the polymer, and the spectrum of the polymer and the amidine group, amide group and lactam were measured. This method employs a method in which the spectrum of a known compound having a group or the like is compared in detail.

[Measurement of Reduced Viscosity] For the polymers A to E,
It was measured as a solution of 0.1 g / dl in 1 N saline at 25 ° C. using an Ostwald viscometer.

[Aggregating agent performance test] Polymers A to E obtained in the above structural examples were used to perform an aggregating performance test. That is, excess sludge (solid content 1.5%, p of commercial activated sludge treatment equipment)
100 ml of H = 6.5) was placed in a 200 ml beaker, and then 10 ml of a 0.25% aqueous solution of each of the polymers A to E was added. Diameter 5mm at tip, length 20mm
Using a stirring bar equipped with three round bars of 1000 r. p. m
And stirred for 10 seconds. The coagulated sludge was filtered with a 60-mesh nylon filter cloth by weight filtration, and the filterable amount (filtered water amount) was measured in a filtration time of 60 seconds.

The sludge after gravity filtration is a 30 cm square polyester monofilament filter cloth (OLh made by Nippon Filcon)
-C) It is sandwiched between two pieces, and is further sandwiched between polyvinyl chloride plates having a drainage groove, and is kept under a piston pressure of 50 kg / cm ² with a hydraulic press having a piston diameter of 20 mm.
Press dehydration was performed for 30 seconds. The water content of the dehydrated sludge was determined from the weight of the dehydrated sludge and the weight of the sludge solid content after drying at 120 ° C. for 3 hours. Table 1 shows the measurement results of the filtered water amount and the water content.

[Heat Stability Test of Coagulant] Polymers A to E were kept in an oven at 120 ° C. for 8 hours, 0.4 g of each polymer was taken, 200 ml of water was added to each, and the mixture was allowed to stand at room temperature for 2 hours.
Stir and mix for hours. The solution was poured onto a rubber flat plate, and the amount of insoluble matter was determined as follows. The results are shown in Table-1. ○: No insoluble matter △: Insoluble particles 2 to 5 ×: Insoluble matter 6 or more XX: Almost insoluble

Comparative Examples 1 and 2 Polymer F (Comparative Example 1) which does not substantially contain a repeating unit having an amidine structure, and a polymer of dimethylaminoethyl acrylate (polymer G) used as a conventional flocculant. The coagulant performance test and thermal stability test of Comparative Example 2) were conducted in the same manner as described above. The results are shown in Table-1.

Comparative Examples 3 to 6 and Examples 6 to 10 In Example 3, the copolymerization of acrylonitrile and N-vinylformamide was amidated by changing the amount of hydrochloric acid, the reaction temperature and the reaction time. Polymers H to O shown in Table 2 were obtained. Comparative Example 6
For, the amount of concentrated hydrochloric acid added was 1 with respect to the formyl group.
Equivalent.

With respect to these polymers, a coagulation performance test was conducted in the same manner as in Example 1 to determine the drainage amount and water content. The results are shown in Table-2.

[0039]

[Table 1]

[0040]

[Table 2]

Examples 11 to 13 A mixture of acrylonitrile and N-vinylformamide containing acrylonitrile in a mole fraction shown in Table 3 in a 50 ml four-necked flask equipped with a stirrer, a nitrogen introducing tube and a cooling tube. 6.0 g and 34.0 g of demineralized water were added. After the temperature was raised to 45 ° C with stirring in a nitrogen gas stream,
0.12 gr of 10% 2,2'-azobis-amiodinopropane dihydrochloride aqueous solution was added. Under stirring, the temperature was maintained at 45 ° C for 4 hours, then raised to 60 ° C and maintained for 3 hours to obtain a suspension in which the polymer was precipitated in water.

The precipitated polymer was separated by filtration and vacuum dried at 40 ° C. to obtain a solid having a water content of 15%. Rotate this 50
Place in a ml eggplant-shaped flask, add an equal amount of concentrated hydrochloric acid to the formyl group in the polymer, and hold at 100 ° C. for 5 hours,
The polymer was amidined. The obtained polymer was added to acetone, washed and vacuum dried to obtain solid polymers Q to S shown in Table 3.

With respect to the polymers Q to S, a coagulation performance test was conducted in the same manner as in Example 1 to determine the drainage amount and water content. The results are shown in Table-3.

[0044]

[Table 3]

Examples 14 to 18 and Comparative Examples 7 to 8 The above polymers A to G are shown in three kinds of organic sludges X to Z.
The coagulation performance test was conducted in the same manner as in Example 1 except that the amount shown in 4 was added, and the drainage and the water content were determined. The results are shown in Table-4.

[0046]

[Table 4]

[0047]

The organic sludge treated with the cationic polymer flocculant of the present invention forms strong flocculation flocs, and therefore the treatment is remarkably efficient. Specifically, a cake having a high filtration rate and a low water content after dehydration can be obtained. In particular, it is effective in treating a large amount of surplus sludge, mixed raw sludge, digested sludge, etc. generated in an urban water treatment plant, and the contribution to the industry in such a direction is enormous.

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Claims (6)

[Claims] 1. A repeating unit represented by the following (1) and / or (2) is 20 to 90 mol%, a repeating unit represented by the following (3) is 0 to 2 mol%, and the following (4) is A repeating unit represented by 0 to 70 mol% and a repeating unit represented by the following (5) were contained in 0 to 70 mol%, and a solution of 0.1 g / dl in 1N saline was measured at 25 ° C. A cationic polymer flocculant having a reduced viscosity value of 0.1 to 10 dl / g. [Chemical 1] (In the formula, R ¹ and R ² represent a hydrogen atom or a methyl group, R ³ represents an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and X ⁻ represents an anion.) 2. A reduction measured at 25 ° C. as a solution containing 50 to 90 mol% of repeating units represented by the following (1) and / or (2) and 0.1 g / dl in 1N saline solution. A cationic polymer flocculant having a viscosity value of 0.1 to 10 dl / g. [Chemical 2] (In the formula, R ¹ and R ² represent a hydrogen atom or a methyl group, R ³ represents an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and X ⁻ represents an anion.) 3. The cationic polymer flocculant according to claim 2, wherein the repeating unit represented by the following (3) is 2 to 20 mol%, and the repeating unit represented by the following (4) is 0 to 48. The repeating unit represented by mol% and the following (5) is 0 to 4
The cationic polymer flocculant according to claim 2, wherein the content is 8 mol%. [Chemical 3] (In the formula, R ¹ and R ² represent a hydrogen atom or a methyl group, R ³ represents an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and X ⁻ represents an anion.) 4. The repeating unit represented by the following (1) and / or (2) is 20 to 90 mol%, the repeating unit represented by the following (3) is 0 to 2 mol%, and the following (4) is used. A repeating unit represented by 0 to 70 mol% and a repeating unit represented by the following (5) were contained in 0 to 70 mol%, and a solution of 0.1 g / dl in 1N saline was measured at 25 ° C. A method for treating organic sludge, comprising adding a cationic polymer flocculant having a reduced viscosity value of 0.1 to 10 dl / g to the organic sludge. [Chemical 4] (In the formula, R ¹ and R ² represent a hydrogen atom or a methyl group, R ³ represents an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and X ⁻ represents an anion.) 5. Reduction as a solution containing 50 to 90 mol% of repeating units represented by the following (1) and / or (2) and 0.1 g / dl in 1N saline solution, measured at 25 ° C. A method for treating organic sludge, which comprises adding a cationic polymer flocculant having a viscosity value of 0.1 to 10 dl / g to the organic sludge. [Chemical 5] (In the formula, R ¹ and R ² represent a hydrogen atom or a methyl group, R ³ represents an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and X ⁻ represents an anion.) 6. The cationic polymer flocculant according to claim 5, wherein the repeating unit represented by the following (3) is 2 to 20 mol%, and the repeating unit represented by the following (4) is 0 to 48 mol%. And a repeating unit represented by the following (5)
8 mol% is contained, The processing method of the organic sludge of Claim 5 characterized by the above-mentioned. [Chemical 6] (In the formula, R ¹ and R ² represent a hydrogen atom or a methyl group, R ³ represents an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and X ⁻ represents an anion.)