JPH0787920B2 - Organic sludge dehydrator - Google Patents

Description

TECHNICAL FIELD The present invention relates to an organic sludge dehydrating agent comprising a water-in-oil type amphoteric polymer emulsion containing a novel amphoteric polyelectrolyte.

[Prior Art] Conventionally, coagulated sedimented sludge and surplus sludge are generated in various industrial wastewater and sewage treatment. In recent years, organic polymer flocculants have been used as dehydrating agents for these sludges. As a method of coagulating and dehydrating sludge, for example, a method of adding a cationic organic polymer coagulant alone, a method of simultaneously adding a cationic organic polymer coagulant and an anionic organic polymer coagulant, and the like are known.

However, the treatment effect is not sufficient in the method of using the cationic organic polymer flocculant alone, and the cake water content,
No satisfactory results have been obtained for vortex velocity.

When the cationic organic polymer flocculant and the anionic organic polymer flocculant are used in combination, the cake water content,
Although the vortex speed may be improved, multiple coagulant dissolution tanks, coagulant reaction tanks, etc. are required, resulting in high equipment costs and large amounts of added chemicals. To do.

In recent years, as shown in JP-B-60-43800, JP-A-58-216706, etc., the cationic organic polymer flocculant and the anionic organic polymer flocculant are used in one solution while controlling the pH of the solution. In the case of the method described above, the cationic organic polymer flocculants that can be used are limited. Further, as disclosed in JP-A-62-205112, in the case of an amphoteric organic polymer flocculant containing a monomer containing a tertiary amine or a quaternary salt as a cation component, the balance of the composition is limited. There is. Many of these polymer flocculants have a powdery form.

[Problems to be Solved by the Invention] When an organic polymer flocculant containing both a cationic and anionic amphotericity is used as an organic sludge dehydrating agent, a comparison is made when a cationic or anionic flocculant is used alone. As a result, the water content of the dehydrated cake decreases.
43800, JP-A-58-216706 and JP-A-62-205112, but their use is limited.

Further, in the case of an amphoteric organic polymer dehydrating agent containing a monomer containing a tertiary amine as a cationic component, there is a limit to the balance of the composition, so that the cation equivalent value, the anion equivalent value and the cation / anion equivalent value are The ratio has its own limit,
No amphoteric organic sludge dehydrating agent having both coagulation performance and dehydration performance has been found.

Further, powdery substances need to be dissolved in water before use.
The dissolution process takes a long time, sometimes the stability of the polymer becomes a problem, and a special diluting device is required.

The present inventors have used aminoalkyl groups as the cationic component, and have studied in detail the composition of the cationic component, the anionic component and the neutral component, and the various properties of the produced organic sludge dehydrating agent. The inventors have found that an organic sludge dehydrating agent that solves these problems can be obtained, and completed the present invention.

[Means for Solving the Problem] The present invention has the general formula (1) [Wherein n is an integer of 1 to 5, a and b are natural numbers of 1 or more, c is 0 or a natural number of 1 or more, and R ¹ , R ² , R ³ and R ⁴ are the same or different and each is a hydrogen atom or Alkyl group, R ⁵ is a hydrogen atom or an alkyl group or an alkyl group substituted with an ω-hydroxy group, HY is a monobasic acid, Z is an amide group represented by the general formula (2), -CONR ⁶ R ⁷ ...... ( 2) (in the formula, R ⁶ and R ⁷ each represent a hydrogen atom or an alkyl group) or a hydroxyalkyl group represented by the general formula (3), (Wherein, R ⁸ and R ⁹ each represent a hydrogen atom or an alkyl group) or a nitrile group represented by the general formula (4), —CN (4) or an ester group represented by the general formula (5). Show.

--COOR ¹⁰ (5) (wherein R ¹⁰ represents an alkyl group, an aromatic group or an alicyclic group)], and preferably has a cation equivalent value (C _V ) of 0.8 to 1
The present invention relates to an organic sludge dehydrating agent comprising a water-in-oil emulsion containing an acid addition salt type amphoteric polymer electrolyte having an anion equivalent value (A _V ) of 0.0 to 6.0 meq / g.

In the present invention, one or more anionic monomers (I) selected from acrylic acid and methacrylic acid, or a monomer composed of a mixture with a nonionic monomer (II) is added to water, a surfactant and Emulsified to water-in-oil type in the presence of a hydrophobic organic solvent, and then polymerized or copolymerized with a radical polymerization catalyst to obtain a vinyl-based carboxylic acid polymer emulsion (II
I) an organic sludge dehydrating agent comprising a water-in-oil amphoteric copolymer emulsion having an aminoalkyl group and a carboxyl group, characterized by reacting alkyleneimine with aminoalkyl, and then acidifying with monobasic acid It is a thing.

Acrylic acid and methacrylic acid are preferred as the anionic monomer (I). The anionic monomer (I) may be neutralized with a base such as sodium hydroxide, potassium hydroxide or ammonia. The neutralization rate of the anionic monomer (I) at this time is in the range of 5 to 100 mol%, preferably 20 to 95 mol%.

Examples of the nonionic monomer (II) include the above-mentioned monomer (I)
Any nonionic monomer copolymerizable with can be used, and for example, a vinyl-type monomer having an amide group represented by the general formula (6) can be used.

In the general formula (6), R ¹¹ , R ¹² and R ¹³ are the same or different and each is hydrogen or an alkyl group, and specific examples thereof include acrylamide, methacrylamide, N, N-dimethylacrylamide and N, N-dimethylmethacrylamide. , N, N-diethyl acrylamide, N, N-diethyl methacrylamide, and the like.

Further, a vinyl-based monomer having a hydroxyalkyl group represented by the general formula (7) can also be used.

In the general formula (7), R ¹¹ , R ¹² and R ¹³ are hydrogen or an alkyl group, and specific examples thereof include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate and hydroxypropyl methacrylate.

Further, a vinyl-based monomer having an ester group represented by the general formula (8) can be used.

In the general formula (8), R ¹⁴ is a hydrogen atom or an alkyl group, R ¹⁵ is an alkyl group, an aromatic group or an alicyclic group, and specific examples include methyl acrylate and acrylic acid n.
-Propyl, iso-propyl acrylate, acrylic acid n
-Butyl, iso-butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate,
Examples thereof include n-butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate and the like. Other examples include acrylonitrile and the like.

The nonionic monomer (II) is used for the purpose of adjusting the molecular weight and ionic equivalent of the organic sludge dehydrating agent.

One or more anionic monomers (I) selected from acrylic acid and methacrylic acid, or nonionic monomers (II)
When emulsifying a monomer consisting of a mixture of the above with water, a surfactant, and a water-in-oil type in the presence of a hydrophobic organic solvent, the surfactant to be used includes an ordinary nonionic surfactant. For example, sorbitan monooleate, sorbitan monostearate, sorbitan monolaurate,
Examples thereof include polyoxyethylene sorbitan monooleate, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, and glycerol monooleate. These nonionic surfactants can be used alone or in a mixture.

Further, these nonionic surfactants can be used in combination with ordinary anionic and cationic surfactants.

Examples of the hydrophobic organic solvent include hydrophobic aliphatic or aromatic hydrocarbons, vegetable or animal oils and modified oils thereof. Typical examples are normal paraffin, isoparaffin, cyclohexane, naphthene, toluene, xylene, kerosene, mineral oil and kerosene.

At this time, the concentration of the total amount of the anionic monomer (I) and the nonionic monomer (II) with respect to the total amount is preferably 20 to 80% by weight. The concentration of the surfactant used with respect to the hydrophobic organic solvent is preferably 5 to 30% by weight. The ratio of the hydrophobic organic solvent and water is 1:10 to 10: 1, preferably 1: 5 to.
It is 3: 1.

One or more anionic monomers (I) selected from acrylic acid and methacrylic acid, or nonionic monomers (II)
After emulsifying a monomer consisting of a mixture with water, a water-in-oil type in the presence of a surfactant and a hydrophobic organic solvent, and then polymerizing or copolymerizing the same, if necessary, a redox system or an azo A radical polymerization initiator such as a system can be used.
Examples of redox-based polymerization initiators include ammonium persulfate, potassium persulfate, hydrogen peroxide, benzoyl peroxide, and tert-butyl peroxide. Examples of the azo-based polymerization initiator include azobis (amidinopropane) hydrochloride, azobisisobutyronitrile, azobis (dimethylvaleronitrile), azobis (cyclohexanecarbonitrile) and the like.

Also, isopropyl alcohol, erythorbic acid, 2-
A known chain transfer agent such as mercaptoethanol may be added.

Regarding the polymerization temperature, the initial temperature is about 10 to 60 ° C, and the temperature is controlled from the outside of the system to carry out the polymerization under the temperature condition of about 30 to 100 ° C.

The polymerization time is about 10 minutes to 10 hours, more preferably about 1 to 7 hours, although it varies depending on the concentration of the monomer, the polymerization temperature, the target degree of polymerization, and the like.

The aminoalkylation reaction can be carried out by reacting the water-in-oil type vinyl carboxylic acid polymer emulsion (III) with an alkyleneimine.

Further, it is necessary to determine the amounts of the water-in-oil type vinyl carboxylic acid polymer emulsion (III) and the alkyleneimine to be used at the time of aminoalkylation.

The water-in-oil type vinyl carboxylic acid polymer emulsion (II
Aminoalkylation is carried out by reacting the acid group of I) with an alkyleneimine.

Alkyleneimines for converting carboxylic acid groups of vinyl polymers to aminoester groups are 1,2-alkyleneimines (maziridine), of which 1,2-propyleneimine and ethyleneimine are available and relatively inexpensive. Therefore, it is particularly preferable. N if desired
-Alkyl-substituted or unsubstituted 1,3-alkyleneimines (azetidines) can also be used to give aminoester groups, since they have similar chemical reactivity and properties to 1,2-imines.

Acidification of the pendant aminoalkyl group is carried out with a monobasic acid,
It is used in an amount of 50 to 100 mol% (preferably 60 to 90 mol%) with respect to the added alkyleneimine, and is carried out collectively or dividedly during aminoalkylation. The monobasic acid is selected from mineral acids such as hydrochloric acid and nitric acid or carboxylic acids such as acetic acid and formic acid.

In the organic sludge dehydrating agent for the water-in-oil type amphoteric copolymer emulsion obtained by the production method of the present invention, it is desirable to appropriately control the molecular weight in addition to the above-mentioned cation equivalent value and anion equivalent value. Intrinsic viscosity [η] of this organic sludge dehydrating agent is used as an indicator of molecular weight.
It is desirable to appropriately set the composition of each monomer, the polymerization conditions, etc. so that the ratio is 0.1 to 25, preferably 1 to 15. In the present invention, an amphoteric organic polymer dehydrating agent is added to form flocs and then dehydrated by a known method. Examples of the dehydrator include a screw press type dehydrator, a filter press type dehydrator and a belt press. A mold dehydrator, a screw decanter, a centrifugal dehydrator or the like can be used.

[Operation] The dehydrating agent for organic sludge of the present invention can be used in the same manner as a cationic flocculant such as a quaternized product of dimethylaminoethyl methacrylate which is conventionally used for organic sludge. The effect is that a small amount of addition forms a strong floc, and press dehydration can significantly reduce the water content of sludge. The overspeed in the overweight step of the press dehydrator is remarkably fast due to the interaction between the cation group and the anion group in the polymer, and the water content is remarkably lowered, and the releasability from the cloth is very good. Since the dehydrated sludge has low tackiness and low water content, it is easy to handle, and the fuel and cost for incineration can be significantly reduced. Organic sludge that is subject to dehydration treatment is generated by primary sludge in sewage treatment, excess sludge in activated sludge treatment and mixtures thereof, and excess sludge in digested activated sludge treatment, digested sludge, and activated sludge from various organic matter-containing wastewater. Excess sludge that can be used.

[Examples] Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited thereto.

(Method for producing organic sludge dehydrating agent) Reference Example 1 100 g of Isopar M (isoparaffin solvent manufactured by Exxon Chemical Co., Ltd.) was placed in a four-necked flask equipped with a stirrer, a thermometer, a cooler, a dropping funnel and a nitrogen gas introducing tube. Dissolve 11.6 g of sorbitan monooleate in it. To this, a mixed solution of 80 g of acrylic acid prepared as a monomer aqueous solution, 20 g of acrylamide, 52.9 g of 28% ammonia water, and 33.9 g of ion-exchanged water was slowly added and emulsified. After the system was sufficiently replaced with nitrogen, the temperature was raised to 60 ° C, 0.7 g of azobis (dimethylvaleronitrile) was added as a catalyst, and the mixture was heated and stirred for 4 hours while maintaining the temperature at 60 ° C. A coalesced emulsion was obtained.

While maintaining this at 50 ° C., 23.9 g of ethyleneimine was added dropwise and stirred for 30 minutes. Then, 57.4 g of a 61 wt% nitric acid aqueous solution was added dropwise, and the mixture was stirred for 30 minutes. Next, 76.1 g of ethyleneimine was added dropwise and stirred for 30 minutes. Then, 110.7 g of 61 wt% nitric acid aqueous solution
The mixture was dropped and stirred for 30 minutes to obtain a target organic sludge dehydrating agent. The reaction conditions are as shown in Table-1.

Reference Examples 2 to 10 The same procedure as in Reference Example 1 was carried out except that the conditions shown in Table 1 were used.

Examples 1 to 6 Mixed raw sludge of sewage treatment plant (pH 6.1, SS1.8Wt%, VSS / SS76.3
%) 150 ml of the predetermined amount of the organic sludge dehydrating agent shown in Table 1 was added, and the mixture was stirred at 300 rpm for 30 seconds to aggregate. 100 ml of coagulated sludge was poured onto a Buchner funnel lined with 100 mesh nylon cloth, and the amount of water after 10 seconds was measured. Then 2 sludge after spent 5 minutes at 0.5 kg / cm ² is sandwiched between the fabric
It was squeezed and dehydrated for minutes, and the water content of the sludge (cake) after dehydration was measured. The results and physical properties are shown in Table 2.

Comparative Examples 1 to 3 Using a quaternized DAM (N, N-dimethylaminoethylmethacrylate) -based high molecular polymer shown in Table 2, the same aggregation test as in Example 1 was performed. The results and physical properties are shown in Table-2.

Examples 7 to 8 Mixed raw sludge of sewage treatment plant (pH6.4, SS1.7Wt%, VSS / SS73.6
%) And the organic sludge dehydrating agent shown in Table 1 was used, and the same coagulation test as in Example 1 was performed. Table of results and physical properties
3 shows.

Comparative Examples 4 to 5 Using the quaternized DAM (N, N-dimethylaminoethyl methacrylate) -based high-molecular polymer shown in Table 3, the same aggregation test as in Example 7 was performed. The results and physical properties are shown in Table-3.

Examples 9-10 Mixed raw sludge (pH6.2, SS1.4Wt%, VSS / SS74.6 of sewage treatment plant
%) And the organic sludge dehydrating agent shown in Table 1 was used, and the same coagulation test as in Example 1 was performed. Table of results and physical properties
4 shows.

Comparative Examples 6 to 7 Using the quaternized DAM (N, N-dimethylaminoethyl methacrylate) -based high molecular polymer shown in Table 4, the same aggregation test as in Example 7 was performed. The results and physical properties are shown in Table-4.

The cation equivalent value, anion equivalent value and intrinsic viscosity shown in Tables 2 to 4 are obtained by the following method.

(1) Cation equivalent value Take 95 ml of distilled water in a beaker, add 5 ml of 1000 ppm sample, adjust to pH 7.0 with 1% HCl or 1% NaOH, stir for about 1 minute, and then add 2 toluidine blue indicator solution. Three drops were added and titrated with N / 400 PVSK (polyvinyl potassium sulfate solution). The titration rate was 2 ml per minute, and the end point was when the test water changed from blue to reddish purple and was held for 10 seconds or longer.

Cation equivalent value (Cv) [meq / g] = (Sample titer [ml] -Blank titer [ml]) x F / 2 x (Active ingredient concentration [ppm] in sample) It is a component obtained by removing the neutralizing acid from the solid content.

(2) Anion equivalent value 50 ml of distilled water was placed in a beaker, and about 0.3 g of a sample was precisely weighed and added. Read the conductivity by titrating with N / 10 NaOH solution while stirring. Read the titer corresponding to the last of several inflection points (where all acids have been neutralized).

Anion equivalent value (Av) [meq / g] = 0.1 x F x (N / 10NaOH titration amount [ml])-(millimeter number of charged neutralizing acid [meq] in precise balance sample) / (in sample Amount of active ingredient [g]) (3) Intrinsic viscosity [dl / g] Dissolve 0.2 parts by weight of sample polymer in 100 parts by volume of water,
Adjust to 4 with hydrochloric acid. 200 ml of this solution 50 ml
Collect in an Erlenmeyer flask with a stopper, add 50 ml of 2N-NaNO ₃ ,
Stir gently to dissolve uniformly. Next, from this solution, 0.02%, 0.04%, 0.06% and 0.08% solutions are prepared.
With 1N-NaNO ₃ in dilution, the pH is adjusted to 4.

Set the Canon Fenske viscometer in a constant temperature bath adjusted to 30 ° C ± 0.1 ° C, put 10 ml of the sample into the viscometer, let it flow naturally, and measure the time required to pass between the upper and lower marked lines of the measuring sphere. . This operation is repeated three times or more and the average value is obtained. 1N
And the blank with -NaNO ₃ solution.

This same operation is performed for 0.02-0.08% solution.

The reduced viscosity is calculated by the following calculation.

Relative viscosity ηrel = t / to Specific viscosity ηsp = (t-to) / to = ηrel-1 Reduced viscosity ηsp / c Each sample concentration is plotted on the horizontal axis and reduced viscosity is plotted on the vertical axis. A straight line passing through each point is plotted, and the value on the vertical axis when the sample concentration is 0 is taken as the intrinsic viscosity.

to = 1N ・ NaNO ₃ flow-down time t = flow-down time of sample solution ηrel = relative viscosity ηsp = specific viscosity c = concentration of sample solution

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Claims (3)

[Claims] 1. An organic sludge dewatering agent, which is a water-in-oil emulsion containing an acid addition salt type amphoteric polymer electrolyte represented by the following general formula. [Wherein n is an integer of 1 to 5, a and b are natural numbers of 1 or more, c is 0 or a natural number of 1 or more, and R ¹ , R ² , R ³ and R ⁴ are the same or different and each is a hydrogen atom or Alkyl group, R ⁵ is a hydrogen atom or an alkyl group or an alkyl group substituted with an ω-hydroxy group, HY is a monobasic acid, Z is an amide group represented by the general formula (2), -CONR ⁶ R ⁷ ...... ( 2) (in the formula, R ⁶ and R ⁷ each represent a hydrogen atom or an alkyl group) or a hydroxyalkyl group represented by the general formula (3), (Wherein R ⁸ and R ⁹ each represent a hydrogen atom or an alkyl group) or a nitrile group represented by the general formula (4), —CN (4) represents an ester group represented by the general formula (5) . —COOR ¹⁰ (5) (wherein R ¹⁰ represents an alkyl group, an aromatic group or an alicyclic group)] 2. A cation equivalent value (C _V ) of an amphoteric polyelectrolyte.
Of 0.8 to 10.0 meq / g, anion equivalent value (A _V ) of 0.1 to 6.0
The organic sludge dehydrating agent according to claim 1, which is in the range of meq / g. 3. A monomer comprising a mixture of at least one anionic monomer (I) selected from acrylic acid and methacrylic acid or a nonionic monomer (II) with water, a surfactant and The water-in-oil type vinyl carboxylic acid polymer emulsion (III) obtained by emulsifying to water-in-oil type in the presence of a hydrophobic organic solvent and then polymerizing or copolymerizing using a radical polymerization catalyst 3. The organic sludge dewatering agent according to claim 1 or 2, which has an aminoalkyl group and a carboxyl group, which is obtained by reacting the above with an aminoalkyl group, and then acidifying with a monobasic acid.