JP2009154081A - Sludge dehydration method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop a prescription for sludge dehydration which suppresses an influence on the environment due to a prescription using an inorganic coagulant and an amphoteric polymer or a cost increase due to a prescription singly using a crosslinkable polymer. <P>SOLUTION: One kind or more selected from (a) a highly cationic and relatively low molecular weight polymerized water-soluble polymer, (b) a polyamidine, (c) an amine-epihalohydrin condensate, and (d) an inorganic coagulant are added to and mixed with sludge. Subsequently, (e) a water-soluble polymer consisting of a cationic or amphoteric water-in-oil emulsion is added thereto and mixed therewith, and then dehydration is carried out. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a method for dewatering sludge, and more specifically, a surfactant having a high cation density and a relatively low molecular weight water-soluble polymer or inorganic flocculant added to and mixed with biologically treated sludge. Is a method of dehydration using a water-in-oil emulsion in which a water-immiscible organic liquid is used as a disperse phase, in which a water-immiscible organic liquid is used as a continuous phase and water is polymerized without the presence of a crosslinking agent. The water-in-oil emulsion is added to and mixed with the biologically treated sludge in the product state without going through a dilution process by water mixing, or a means for mixing the water-in-oil emulsion with water is connected in the middle of the pipe. Further, the present invention relates to a sludge dewatering method, characterized in that a dilution obtained by continuous dissolution is added to the biologically treated sludge, mixed and dehydrated.

Various prescriptions to improve sludge dewatering efficiency have been proposed,
As a typical example, Patent Document 1 is to dehydrate by adding an amphoteric polymer having a specific ionicity after adjusting the pH after adding an inorganic coagulant to 5-8. Thereafter, the formulation using both inorganic and amphoteric polymers has been improved and Patent Document 2 uses an amphoteric polymer obtained by copolymerizing an acrylate cationic monomer and a methacrylate cationic monomer at a specific ratio. An example using a mixture of two amphoteric polymers has also been proposed (Patent Document 3). Furthermore, the crosslinkable polymer may exhibit high performance specifically depending on the sludge, and has been studied for a long time. Patent Document 4 discloses a coagulation treatment method using a polymer having a high degree of crosslinking. Yes. Moreover, there exists patent document 5 as an example using the polymer with comparatively low bridge | crosslinking degree. Recently, there is a polymer having a polyoxyalkylene chain (Patent Document 6).

Typical recipes aimed at improving the currently known sludge dewatering method are as described above, a combination of inorganic and amphoteric polymers, a mixture of two or more amphoteric polymers, a method using a crosslinked polymer, polyoxy A polymer having an alkylene chain.
Among these, a formulation in which two or more amphoteric polymers are mixed can be applied from a powder to a water-in-oil emulsion as a product form. On the other hand, amphoteric water-soluble polymers have a wide range of use such as combined use with inorganic coagulants, and in some cases, it is also possible to efficiently dewater difficult-to-dewater sludge in the same manner as crosslinkable water-soluble polymers. To date, there is no known sludge dewatering method using a combination of a water-soluble polymer having a high cation density and a relatively low molecular weight and a crosslinkable ionic water-soluble polymer.

JP 63-158200 A Japanese Patent Laid-Open No. 7-256300 JP 2003-117309 A JP-A 61-293510 JP-A-9-225499 JP 2005-68336 A

A single formulation using a crosslinkable polymer has a problem of an increase in cost due to an increase in addition amount. Accordingly, an object of the present invention is to develop a sludge dewatering formulation that suppresses cost increase due to a single formulation with a crosslinkable polymer.

In order to solve the above-mentioned problems, the present inventors have intensively studied and as a result, have reached the invention described below. That is, the invention of claim 1 is such that the monomer represented by the following general formula (1) and / or (2) is 70 to 100 mol%, the monomer represented by the following general formula (3) is 0 to 30 mol%, (A) a water-soluble polymer obtained by polymerizing a monomer mixture consisting of 0 to 30 mol% of a water-soluble nonionic monomer, (b) a polyamidine represented by the following general formula (4) and / or (5), One or more selected from (c) amine / epihalohindrin condensate and (d) inorganic flocculant are added to and mixed with the biologically treated sludge, and (e) organic immiscible with water by the surfactant. A method for dehydration using a water-in-oil emulsion in which a liquid is a continuous phase and a water-soluble polymer containing water polymerized in the absence of a crosslinking agent is used as a dispersed phase, the water-in-oil emulsion being water Water-in-oil emulsion without dilution by mixing In addition to the biological treatment sludge is dehydrated method sludge characterized by mixing.
General formula (1)
General formula (2)
R ₁ and R ₅ are hydrogen or a methyl group, R ₂ , R ₃ and R ₆ are an alkyl group having 1 to 3 carbon atoms or a benzyl group, and may be the same or different. R ₄ and R ₇ are hydrogen, an alkyl group having 1 to 3 carbon atoms, or a benzyl group. A represents an oxygen atom or NH, B represents an alkylene group having 2 to 4 carbon atoms, and X ₁ and X ₂ each represents an anion.
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 is hydrogen or COOY ₂ , Y ₁ or Y ₂ is hydrogen or a cation.
R ₁₂ and R ₁₃ each represent hydrogen or a methyl group, and X ₃ represents an anion.

The invention of claim 2 is such that the monomer represented by the following general formula (1) and / or (2) is 70 to 100 mol%, the monomer represented by the following general formula (3) is 0 to 30 mol%, (A) a water-soluble polymer obtained by polymerizing a monomer mixture comprising 0 to 30 mol% of a nonionic monomer, (b) a polyamidine represented by the following general formula (4) and / or (5), c) One or more selected from amine / epihalohindrin condensate and (d) inorganic flocculant are added to and mixed with biologically treated sludge, and (e) an organic liquid immiscible with water by a surfactant. Using a water-in-oil emulsion containing a water-soluble polymer containing water polymerized in the absence of a cross-linking agent as a dispersed phase, wherein the water-in-oil emulsion is mixed with water. And mixing means in the middle of the pipe, continuously dissolved, obtained Adding diluent to the biological treatment sludge is dehydrated method sludge characterized by mixing.
General formula (1)
General formula (2)
R ₁ and R ₅ are hydrogen or a methyl group, R ₂ , R ₃ and R ₆ are an alkyl group having 1 to 3 carbon atoms or a benzyl group, and may be the same or different. R ₄ and R ₇ are hydrogen, an alkyl group having 1 to 3 carbon atoms, or a benzyl group. A represents an oxygen atom or NH, B represents an alkylene group having 2 to 4 carbon atoms, and X ₁ and X ₂ each represents an anion.
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 is hydrogen or COOY ₂ , Y ₁ or Y ₂ is hydrogen or a cation.
R ₁₂ and R ₁₃ each represent hydrogen or a methyl group, and X ₃ represents an anion.

The invention according to claim 3 is the sludge dewatering method according to claim 1 or 2, wherein the water-soluble polymer (a) has a weight average molecular weight of 1,000,000 to 5,000,000.

The invention of claim 4 is characterized in that the (c) amine / epihalohindrin condensate is a condensate of epichlorohydrin with one or more selected from aliphatic monoamines and aliphatic polyamines. The method for dewatering sludge according to claim 1 or 2.

The invention of claim 5 is the sludge dewatering method according to claim 1 or 2, wherein the surfactant has an HLB (hydrophilic lipophilic balance) of 11 to 20.

The sludge dewatering method of the present invention comprises: (a) a highly cationic water-soluble polymer having a relatively low molecular weight and a weight average molecular weight of 1,000,000 to 5,000,000, and (b) an amine / epihalohin. After adding and mixing one kind selected from drin condensate, (c) polyamidine or (d) inorganic flocculant to biologically treated sludge, (e) continuous phase of water-immiscible organic liquid with surfactant. A method of dehydrating using a water-in-oil emulsion having a water-soluble polymer containing water polymerized in the absence of a crosslinking agent as a dispersed phase, wherein the water-in-oil emulsion is mixed with water. Add to the biologically treated sludge in the state of a water-in-oil emulsion without passing through the process, or mix the water-in-oil emulsion with water in the middle of the pipe and dissolve continuously. Obtain the diluted solution before It added to the biological treatment sludge, after mixing, characterized by dewatering.

The cationic or amphoteric water-soluble polymer emulsion contains 20 to 100 mol% of the monomer represented by the general formula (1) and / or (2), and the monomer 0 represented by the general formula (3). It is preferable to polymerize a monomer mixture composed of ˜30 mol% and water-soluble nonionic monomer 0-80 mol%. The amine / epihalohindrin condensate is preferably a condensate of one or more selected from aliphatic monoamines and aliphatic polyamines with epichlorohydrin. Inorganic flocculants can also be used. Furthermore, it is preferable that HLB (hydrophilic lipophilic balance) of the said surfactant is 11-20.

The present invention will be specifically described below. The sludge dewatering treatment method of the present invention is characterized in that two kinds of chemicals are added as one agent and two agents to the sludge in two stages.
That is, it is selected from (a) a water-soluble polymer, (b) a polyamidine represented by the following general formula (4) and / or (5), (c) an amine / epihalohindrin condensate, and (d) an inorganic flocculant. (E) a method of dehydrating using a water-in-oil emulsion after adding or mixing one or more of them to biologically treated sludge. In the sludge dewatering treatment, a high cationic polymer is often used with an emphasis on reducing the moisture content of the dehydrated cake. However, the flocs are small, and even if excessively added, the flocs remain small and the solid-liquid separation rate is low. As a countermeasure for this, the present inventor, when added in this order at a ratio of 3: 7 to 9.5: 0.5 with one agent and two agents of different types, is remarkably superior to the treatment with one type. It was discovered that the result was obtained.

The reason is considered as follows. That is, by adding the first polymer, a part of the surface charge of the suspended component is neutralized and relatively large particles are aggregated to form small aggregated flocs. At this time, among the suspended components, the components having a small particle size or strong hydrophilicity remain without being aggregated and dispersed. Neutralizing and agglomerating the surface charge by adding the second cationic polymer or amphoteric polymer, the component remaining in the dispersed state is adsorbed on the floc already formed by the addition of the first polymer, Forms a floc that is large and hard to break, enabling rapid solid-liquid separation. As a result, the solid-liquid separation rate in the dehydrator increases, the amount of sludge treatment per hour increases, and the dehydration time is shortened. Since a flock that is not easily broken is formed, the moisture content of the dehydrated cake is reduced, and the suspended components in the separated liquid are reduced, thereby improving the recovery rate. If the required amount is added and aggregated only with the first polymer flocculant here, only small and fragile flocs are formed, and the solid-liquid separation rate in the dehydrator is slowed down and the amount of dehydration per hour is reduced. . In addition, when a necessary amount of only the second cationic or amphoteric water-soluble polymer is added and agglomerated, flocs are formed but the surface charge of the sludge particles is insufficiently neutralized, and the water content of the dehydrated cake Is higher than the treatment with one agent, or the required amount of cationic or amphoteric water-soluble polymer is increased. The compatibility ratio of one agent and two agents changes depending on the sludge properties, and a good sludge dewatering state can always be obtained by changing the ratio. However, in the state where the first agent is added excessively and there is no unaggregated suspended component, the polymer of the second agent cannot exert the aggregating effect and the dehydrating performance is not improved. Even if one agent and two agents are mixed and added, the effect is not exerted, and even if the order of addition is changed, a good dehydration treatment cannot be performed.

(A) The cation amount of the highly cationic water-soluble polymer is preferably 70 mol% or more, more preferably 80 to 100 mol%. Moreover, molecular weight is 1 million or more and 5 million or less in a weight average molecular weight, More preferably, it is 2 million to 4 million. The cation amount of the amphoteric water-soluble polymer is 20 mol% or more, preferably 40 to 80 mol%. The molecular weight is preferably 1 million or more and 10 million or less, more preferably 3 million to 7 million in terms of weight average molecular weight.

The water-soluble polymer (a) used in the present invention can polymerize the following monomers. That is, it contains one or more selected from structural units represented by the following general formulas (1) to (2) and a nonionic structural unit. The polymer containing the structural unit represented by the general formula (1) is a (meth) acrylic cationic polymer. This water-soluble polymer can be synthesized by copolymerization of a cationic monomer and a nonionic monomer. Examples of cationic monomers include dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, or quaternary ammonium with monohalides of these monomers. Salt. Examples thereof include (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxy 2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, and the like. These cationic monomers can be used in combination of two or more. The mol% of the cationic monomer is 70 to 100 mol%, preferably 80 to 100 mol%.
General formula (1)
General formula (2)
R ₁ and R ₅ are hydrogen or a methyl group, R ₂ , R ₃ and R ₆ are an alkyl group having 1 to 3 carbon atoms or a benzyl group, and may be the same or different. R ₄ and R ₇ are hydrogen, an alkyl group having 1 to 3 carbon atoms, or a benzyl group. A represents an oxygen atom or NH, B represents an alkylene group having 2 to 4 carbon atoms, and X ₁ and X ₂ each represents an anion.

As an example of the nonionic monomer, acrylamide is most preferably used, but a nonionic monomer other than acrylamide may be copolymerized. Examples thereof include N, N-dimethylacrylamide, vinyl acetate, acrylonitrile, methyl acrylate, 2-hydroxyethyl (meth) acrylate, diacetone acrylamide, N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, Examples include acryloylmorpholine.

The cationic polymer flocculant containing the structural unit represented by the general formula (2) can be synthesized by copolymerization of a dialkyldi (meth) allylammonium salt and a nonionic monomer. Examples of dialkyldi (meth) allylammonium salts include dimethyldi (meth) allylammonium chloride, diethyldi (meth) allylammonium chloride, methylbenzyldi (meth) allylammonium chloride, and the like. The nonionic monomer can be the nonionic monomer. The mol% of the cationic monomer is 70 to 100 mol%, preferably 80 to 100 mol%.

In addition, the water-soluble polymer (a) used in the present invention contains 1 to 30 mol% of an anionic group selected from the structural unit represented by the following general formula (3), and is highly amphoteric and water-soluble. It can also be used as a molecule. As an example of the anionic monomer, either a monomer having a sulfonic acid group or a carboxyl group can be used, and both may be used in combination. Examples of the sulfonic acid group-containing monomer include vinyl sulfonic acid, vinyl benzene sulfonic acid, and 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.
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 is hydrogen or COOY ₂ , Y ₁ or Y ₂ is hydrogen or a cation.

The (b) polyamidine used in the present invention has the following physical properties and can be produced as follows. That is, in general, a copolymer comprising a vinyl monomer having a primary amino group or a substituted amino group capable of forming a primary amino group by a conversion reaction, and acrylonitrile or methacrylonitrile is produced. It can be obtained by reacting the cyano group and primary amino group in order to amidine.

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 by copolymerizing N-vinylformamide and acrylonitrile in accordance with the above-described explanation. The union is usually prepared by heating as an aqueous suspension in the presence of hydrochloric acid to form amidine units from the cyano group adjacent to the substituted amino 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%. . The molecular weight is 100,000 to 10,000,000, preferably 1,000,000 to 6,000,000 in terms of weight average molecular weight.

The (c) amine / epihalohydrin condensate used in the present invention is a polycondensate of at least one compound selected from ammonia, an aliphatic monovalent amine and an aliphatic polyamine with an epihalohydrin. Examples of the aliphatic monovalent amine include monomethylamine, monoethylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, mono-, di- and tri-ethanolamines. Aliphatic polyamines include ethylenediamine, diethylenetriamine, triethylenetetramine, pentaethylenehexamine, hexamethylenediamine, dimethylaminopropylamine, hexamethylenediamine and the like. Particularly preferred among these amines are ammonia, monomethylamine, dimethylamine, trimethylamine, ethylenediamine, and pentaethylenehexamine. The amine / epihalohydrin condensate may be a product obtained by reacting these ammonia, aliphatic monovalent amine or aliphatic polyamine alone or in a mixture of two or more with epihalohydrin. A product having a molecular weight increased by reacting a monovalent amine with epihalohydrin to form a condensate and reacting with ammonia or an aliphatic polyamine in the second stage of the reaction may be used. The molecular weight of the amine / epihalohydrin condensate is several hundred to about 100,000 in terms of weight average molecular weight.

As the inorganic flocculant (d) used in the present invention, general inorganic flocculants such as sulfuric acid band, ferric chloride, polyaluminum chloride and the like can be used, and one or more of these are used in combination. It is also possible to do.

The (e) cationic or amphoteric water-in-oil emulsion used in the present invention is a mixture of the above-described cationic monomer, nonionic monomer, and anionic monomer monomer. Manufactured by water-in-water emulsion polymerization.

For example, in a water-in-oil emulsion polymerization method, a monomer mixture consisting of a monomer or two or more copolymerizable monomers and a crosslinkable monomer is mixed with water, at least one water. An oily substance composed of a hydrocarbon, an effective amount for forming a water-in-oil emulsion, and at least one surfactant having HLB are mixed and stirred vigorously to form a water-in-oil dispersion, followed by polymerization. It is the method of synthesize | combining by doing.

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

Examples of at least one surfactant having an amount effective to form a water-in-oil dispersion and HLB are HLB 3-13 nonionic surfactants, specific examples of which are oil-soluble interfaces. Examples of the activator include sorbitan monooleate, sorbitan monostearate, sorbitan monopalmitate and the like. Nonionic water-soluble surfactants include polyoxyethylene alkyl ether, polyoxyethylene alcohol ether, and polyoxyethylene alkyl ester. Specifically, polyoxyethylene (20) sorbitan trioleate, polyoxyethylene (4) sorbitan monostearate, polyoxyethylene (5) sorbitan monooleate and the like. The addition amount of these surfactants is 0.5 to 10% by weight, preferably 1 to 5% by weight, based on the total amount of the water-in-oil emulsion.

After the polymerization, a hydrophilic interfacial modifier called a phase inversion agent is added to make the dispersed particles covered with the oil film easy to adjust to water, and the water-soluble polymer inside is easily dissolved as necessary. Dilute with water and use for each application. Examples of hydrophilic interfacial chemicals are cationic interfacial chemicals and nonionic interfacial chemicals of HLB 9-15, such as polyoxyethylene polyoxypropylene alkyl ether systems and polyoxyethylene alcohol ether systems. is there.

The (e) cationic or amphoteric water-soluble polymer used in the present invention uses a water-in-oil emulsion because it has the following advantages. After preparing a water-in-oil emulsion using a surfactant and a water-immiscible organic liquid that is a water-immiscible organic liquid as a continuous phase and a water-containing monomer or monomer mixture as a dispersed phase. , Polymerized into a product. The water-in-oil emulsion can be added to and mixed with sludge in a product state without going through a dilution process by water mixing. This method can be added to the sludge without installing a stirrer or a diluting liquid storage tank, so the cost is very low and no space is required. Further, particularly preferably, when a water-in-oil emulsion is prepared using a high HLB (hydrophilic lipophilic balance) surfactant, the solubility in water is good, so-called fish eyes are not formed, Suitable for addition in the product state. In addition, when added to sludge in the product state, it will be added in a high concentration state, improving the dewaterability of sludge and reducing the amount of addition from the viewpoint of non-crosslinkable water-soluble polymer and crosslinkable water-soluble Compared to polymer blends, the effect is excellent.

Further, the cationic or amphoteric water-soluble polymer used in the present invention has a means for mixing the water-in-oil emulsion and water in the middle of the pipe, dissolves continuously, and dilutes the liquid without storing it in the storage tank. It is characterized by being added to and mixed with. This method is also the same as described in the previous paragraph. Also in this case, when a water-in-oil emulsion is prepared using a high HLB (hydrophilic / lipophilic balance) surfactant, the solubility in water is good, and after line dissolution, it is added to sludge. Suitable for In this way, whether to dissolve in the line and add the diluent directly or in the product state should be determined by the properties of the sludge, the performance of the stirrer, and the like.

As a means for mixing the water-in-oil emulsion and water, a general line mixer can be used. A pump may be used instead of the line mixer. When dissolution is insufficient with one unit, two units can be connected in series. The line mixer is relatively inexpensive compared to a pump, has a simple structure, is light in weight, is easy to handle, and is very convenient to use. Specific examples include Kalman Mixer Series-F1, F2, F3, KS2, and KT2 manufactured by Chilling Industries Co., Ltd.

The dehydrator can perform dehydration using a conventional model such as a belt press, screw press, rotary press, filter press, or decanter, but is preferably a belt press, a screw press, or a rotary press. In addition to sewage digested sludge, it can be applied to sewage surplus sludge or raw sludge, other biological wastewater sludge from industrial wastewater, pulp sludge in paper industry, general wastewater sludge, and the like.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following Examples unless it exceeds the gist.

The sludge dewatering treatment method of the present invention was carried out using sewage digested sludge (pH 7.65, ss content 31,500 mg / L). The sludge was supplied at 0.5 m ³ / hr to the coagulation mixing tank-1 equipped with a stirrer, and a 0.3 mass% aqueous solution of Sample-1 in Table 1 was supplied at 9.9 L / hr (vs. 15% by mass). Thereafter, Sample -5 (acryloyloxyethyltrimethylammonium chloride 50 mol% / acrylamide 50 mol% copolymer) was supplied in a dispersion state at a concentration of 99.4 mL / hr in the coagulation mixing tank-2 (vs. ss). 0.2 mass%). While observing the floc diameter of the agglomerated sludge, it was sent to a belt press dehydrator (raised one-sheet filter cloth type) for dehydration. Thereafter, the filter cloth peelability and the moisture content of the dehydrated cake discharged from the belt press dehydrator were measured (dried at 105 ° C. for 20 hours). The combination of Sample-1 and Sample-6, Sample-4 and Sample-6, and Sample-7 and Sample-6 was performed in the same manner. The results are shown in Table 2.

(Comparative Test 1) After each sample was dissolved in 0.3% by mass for comparison, a 0.3% by mass aqueous solution was added to the coagulation-mixing tank-1, and a 0.3% by mass aqueous solution was added to the coagulation-mixing tank-2. The test was conducted. The results are shown in Table 2.

(Table 1)

(Table 2)
Moisture content of cake: mass%, chemical injection amount: ss mass%, ND; data cannot be acquired

The sludge dewatering method of the present invention was carried out using sewage sludge and excess mixed sludge (pH 6.35, ss content 37, 300 mg / L). The sludge was supplied at 0.5 m ³ / hr to the coagulation mixing tank-1 equipped with a stirrer, and a 0.3 mass% aqueous solution of Sample-2 in Table 1 was supplied at 9.9 L / hr (vs. 15% by mass). Thereafter, Sample 5 (acryloyloxyethyltrimethylammonium chloride 50 mol% / acrylamide 50 mol% copolymer) was mixed with dilution water in a coagulation mixing tank-2 with a line mixer installed in the middle of the pipe, and 0.3 A dissolved solution of mass% was prepared and supplied at 13.2 mL / hr (0.20 mass% for ss). While observing the floc diameter of the agglomerated sludge, it was sent to a belt press dehydrator (raised one-sheet filter cloth type) for dehydration. Thereafter, the filter cloth peelability and the moisture content of the dehydrated cake discharged from the belt press dehydrator were measured (dried at 105 ° C. for 20 hours). The combination of Sample-3 and Sample-5, Sample-4 and Sample-6, and Sample-7 and Sample-6 was performed in the same manner. The results are shown in Table 3.

(Comparative Test 2) As a comparison, after each sample was dissolved in 0.3% by mass, a test was carried out in which 0.35% by mass of a 0.3% by mass aqueous solution was added to the ss component 0.35% by mass in the coagulation mixing tank-1. . The results are shown in Table 3.

(Table 3)
Moisture content of cake: mass%, chemical injection amount: ss mass%, ND; data cannot be acquired

Claims (5)

70 to 100 mol% of a monomer represented by the following general formula (1) and / or (2), 0 to 30 mol% of a monomer represented by the following general formula (3), a water-soluble nonionic monomer (A) a water-soluble polymer obtained by polymerizing a monomer mixture composed of 0 to 30 mol%, (b) a polyamidine represented by the following general formula (4) and / or (5), (c) an amine / epihalohin One or more selected from a drin condensate and (d) an inorganic flocculant are added to and mixed with the biologically treated sludge, and (e) a water-immiscible organic liquid is made into a continuous phase by a surfactant to form a crosslinking agent. A method of dehydrating using a water-in-oil emulsion having a water-soluble polymer containing water polymerized without the presence of water as a dispersed phase, wherein the water-in-oil emulsion is not subjected to a dilution process by water mixing. Added to the biological treatment sludge in the form of a water-in-water emulsion. Mixing dehydrated method sludge, characterized by.
General formula (1)
General formula (2)
R ₁ and R ₅ are hydrogen or a methyl group, R ₂ , R ₃ and R ₆ are an alkyl group having 1 to 3 carbon atoms or a benzyl group, and may be the same or different. R ₄ and R ₇ are hydrogen, an alkyl group having 1 to 3 carbon atoms, or a benzyl group. A represents an oxygen atom or NH, B represents an alkylene group having 2 to 4 carbon atoms, and X ₁ and X ₂ each represents an anion.



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 is hydrogen or COOY ₂ , Y ₁ or Y ₂ is hydrogen or a cation.
R ₁₂ and R ₁₃ each represent hydrogen or a methyl group, and X ₃ represents an anion. 70 to 100 mol% of a monomer represented by the following general formula (1) and / or (2), 0 to 30 mol% of a monomer represented by the following general formula (3), a water-soluble nonionic monomer (A) a water-soluble polymer obtained by polymerizing a monomer mixture composed of 0 to 30 mol%, (b) a polyamidine represented by the following general formula (4) and / or (5), (c) an amine / epihalohin One or more selected from a drin condensate and (d) an inorganic flocculant are added to and mixed with the biologically treated sludge, and (e) a water-immiscible organic liquid is made into a continuous phase by a surfactant to form a crosslinking agent. A method of dehydrating by using a water-in-oil emulsion having a water-soluble polymer containing water polymerized without the presence of water as a dispersed phase, the means for mixing the water-in-oil emulsion with water in the middle of piping And continuously lysing the diluted solution obtained from the organism. Added sense sludge dehydration treatment methods sludge characterized by mixing.
General formula (1)
General formula (2)
R ₁ and R ₅ are hydrogen or a methyl group, R ₂ , R ₃ and R ₆ are an alkyl group having 1 to 3 carbon atoms or a benzyl group, and may be the same or different. R ₄ and R ₇ are hydrogen, an alkyl group having 1 to 3 carbon atoms, or a benzyl group. A represents an oxygen atom or NH, B represents an alkylene group having 2 to 4 carbon atoms, and X ₁ and X ₂ each represents an anion.
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 is hydrogen or COOY ₂ , Y ₁ or Y ₂ is hydrogen or a cation.
R ₁₂ and R ₁₃ each represent hydrogen or a methyl group, and X ₃ represents an anion. 3. The sludge dewatering method according to claim 1, wherein the water-soluble polymer (a) has a weight average molecular weight of 1,000,000 to 5,000,000. 3. The (c) amine / epihalohindrin condensate is a condensate of epichlorohydrin with one or more selected from aliphatic monoamines and aliphatic polyamines. Sludge dehydration method. The method for dewatering sludge according to claim 1 or 2, wherein the surfactant has an HLB (hydrophilic lipophilic balance) of 11 to 20.