JP4529554B2 - Wastewater treatment method - Google Patents

Description

  The present invention relates to a wastewater treatment method for treating wastewater containing at least a nitrogen component generated from a manufacturing process of an electrostatic charge image developing toner.

  Conventionally, as wastewater generated from a toner manufacturing factory, wastewater containing an aqueous surfactant solution, a pigment dispersion, a wax dispersion, an aqueous solution containing a nitrogen component, an aqueous emulsion, and the like has been generated. Since these wastewater contains the above-mentioned surfactant, pigments which are coloring components, etc., they cannot be discharged into rivers, sewers or the like as they are. For this reason, these wastewaters are discharged outside after being treated at a wastewater treatment facility in the factory. As the wastewater treatment, coagulation sedimentation treatment is often used. Coagulation and sedimentation treatment is the most commonly used in the field of wastewater treatment, as described in the 5th edition pollution prevention technology and legal water quality edition (supervised by the Ministry of International Trade and Industry, Environmental Location Bureau, issued in 2001) p141. This is one of the solid-liquid separation operations that are widely used. The coagulation sedimentation treatment is a treatment method in which flocs (coarse particles generated by coagulation) are generated by adding a coagulant to the wastewater, and the flocs precipitate due to the difference in specific gravity between water and flocs to perform solid-liquid separation. The floc thus separated as a solid is treated as sludge for industrial waste, and the water from which the solid has been separated is discharged into rivers, sewers and the like.

  In Patent Document 1, in a wastewater treatment method for solid-liquid separation of organic pollutant-containing wastewater, a wastewater treatment method that facilitates final treatment of sludge by returning a part of the generated sludge to the treated raw water side and circulating it. Is disclosed. However, when this method is used for the treatment of an aqueous solution containing a nitrogen component, the mechanism is not well understood due to the action of the nitrogen, but a problem that sludge hardly settles occurs. On the other hand, Patent Document 2 discloses a method of performing pressure levitation separation for the treatment of emulsion wastewater. However, this method can treat emulsion wastewater, but cannot be applied as it is to all types of wastewater generated from toner manufacturing plants.

JP-A-7-136408 Japanese Patent Laid-Open No. 9-225474

  For example, in the coagulation sedimentation treatment of wastewater containing multicomponents generated from a toner manufacturing factory, the sedimentation property in a floc sedimentation tank or the like is poor, and a very long sedimentation treatment is required for solid-liquid separation. Furthermore, in order to coagulate and precipitate nitrogen components contained in wastewater, it is necessary to add a large amount of coagulant, which causes inefficiency in that a large amount of sludge is generated as industrial waste. .

  Therefore, an object of the present invention is to provide a wastewater treatment method that efficiently settles sludge even with a small amount of a coagulant used and reduces the amount of sludge generated.

  The present invention has the following features.

(1) A wastewater treatment method for treating wastewater containing at least a surfactant and a nitrogen component generated from a manufacturing process of an electrostatic charge image developing toner, wherein the surfactant and nitrogen component generated from the manufacturing process A wastewater treatment method comprising: a step of performing a coagulation sedimentation treatment on the wastewater to be included ; and a step of removing a nitrogen component by anaerobic treatment of the wastewater after the coagulation sedimentation treatment is performed .

  (2) In the wastewater treatment method according to (1), the step of treating the nitrogen component is a wastewater treatment method comprising a methane fermentation process.

  (3) A wastewater treatment method for treating wastewater containing at least a nitrogen component generated from a manufacturing process of an electrostatic charge image developing toner, and subjecting the wastewater containing a nitrogen component generated from the manufacturing process to coagulation sedimentation treatment It is a wastewater treatment method provided with the process of removing by anaerobic treatment after performing.

  (4) A wastewater treatment method for treating wastewater containing at least a nitrogen component generated from a predetermined manufacturing process, and anaerobic after performing a pressure levitation treatment of the wastewater containing a nitrogen component generated from the manufacturing process It is the waste water treatment method provided with the process removed by a property process.

  ADVANTAGE OF THE INVENTION According to this invention, the amount of the flocculant used for the process of the waste_water | drain containing at least a nitrogen component which generate | occur | produces from a manufacturing process, and the generation amount of the sludge generated by a waste_water | drain process can be reduced. Moreover, the nitrogen content in the wastewater after wastewater treatment can be greatly reduced.

  As a manufacturing process that requires the waste water treatment, a toner manufacturing process will be described below as an example.

  The toner production process is divided into a production process of a latex polymer, a colorant dispersion, a release agent dispersion and other dispersions, which are raw materials of the toner, and a development toner production method. Below, an example is given and demonstrated about each.

[Latex polymer production process]
In order to produce a latex polymer, a monomer and an anionic surfactant are usually added to water and stirred to form an emulsion. Once the monomer emulsion is formed, 25 wt% or less of the monomer emulsion (ie, a small amount of monomer emulsion) and the free radical initiator are added to the aqueous phase and mixed to initiate seed polymerization at the desired reaction temperature. After the seed particles are formed, a monomer emulsion is further added to the seed particle-containing composition, and polymerization is continued at a specified temperature for a desired time to complete the polymerization, thereby forming a latex polymer. From the latex polymer production process, an emulsion aqueous solution that is no longer necessary in the production process or generated during equipment maintenance in the production process is discharged.

  In addition, the manufacturing method of a latex polymer is not restricted to the above-mentioned method, What kind of manufacturing method may be used if it is emulsion polymerization and suspension polymerization.

  The monomer is not particularly limited as long as it can react with a free radical initiator. Specific examples of the monomer include homopolymers or copolymers of styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, acrylic Homopolymers or copolymers of esters having vinyl groups such as lauryl acid, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; acrylonitrile And homopolymers or copolymers of vinyl nitriles such as methacrylonitrile.

  Further, a resin such as polyester or polyurethane having self-emulsifying properties may be sheared and dispersed in an aqueous medium together with a surfactant. Moreover, what contains an ammonia component as a latex polymer is also used.

  [Method for Producing Toner for Development] The latex polymer obtained by the above preparation method is used for the preparation of toner by the following method. A flocculant and / or a charge additive and / or other additives are mixed with the latex polymer prepared by the method described in the present invention and at least a plurality of dispersions containing a colorant, if necessary, and the resulting mixture is obtained. Is heated at a temperature near the Tg of the latex polymer, preferably Tg ± 10 ° C. of the latex polymer for an effective time, for example, 1-8 hours, to produce toner-sized aggregates. The aggregate suspension is then heated to a Tg of the latex polymer or higher, for example from about 60 to about 120 ° C. to coalesce or coalesce to granulate toner particles, which are filtered, etc. It is separated from the mother liquor by means, washed with ion-exchanged water or the like (washing process), and then dried.

  The latex polymer is usually used as a binder resin for toner, and is present in the toner at about 75 to 98% by weight. The size of the latex polymer suitable for the production method of the present invention can be measured with a laser diffraction type particle size distribution analyzer, for example, a volume average particle size measured with a microtrack (manufactured by Nikkiso Co., Ltd.), 0.05 to It is about 1 μm.

  The colorant is usually present in an effective amount in the toner, for example, about 1 to 15% by weight, preferably about 3 to 10% by weight of the toner. Moreover, the magnitude | size is a volume average particle diameter measured with this microtrack, for example, and is about 0.05-0.5 micrometer.

  The flocculant can be used in an effective amount, for example, about 0.01 to 10% by weight based on the solid content of the toner. As the aggregating agent to be used, a compound having a monovalent or higher charge is preferable. Specific examples of the compound include the above-mentioned ionic surfactants, acids such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid, oxalic acid, and chloride. Examples thereof include, but are not limited to, magnesium, sodium chloride, aluminum sulfate, calcium sulfate, ammonium sulfate, aluminum nitrate, silver nitrate, copper sulfate, sodium carbonate, and polyaluminum chloride. Preferred flocculants include those having a nitrogen component such as nitric acid.

  An effective amount of the charge control agent may be used, for example, 0.1 to 5% by weight of the toner. Suitable charge control agents include, but are not limited to, alkyl pyridinium halides, bisulfates, charge control agents such as silica, and negative charge control agents such as aluminum complexes. Examples of other additives used include waxes that act as mold release agents. A preferable amount of the wax is about 5 to 20% by weight based on the solid content of the toner.

  The type of wax is not particularly limited. For example, low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene; silicones having a softening point; fatty acids such as oleic acid amide, erucic acid amide, ricinoleic acid amide, and stearic acid amide Amides; plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax And mineral waxes such as petroleum waxes; ester waxes of higher fatty acids such as stearyl stearate and behenyl behenate and higher alcohols.

  Examples of inorganic fine particles to be wet-added include silica, alumina, titania, calcium carbonate, magnesium carbonate, and tricalcium phosphate, all of which are usually used as external additives on the toner surface, such as ionic surfactants and polymers. It can be dispersed in water with an acid or a polymer base and added wet.

  From the toner production process, an aqueous surfactant solution, a pigment dispersion, a wax dispersion, and an aqueous solution containing a nitrogen component that are no longer necessary in the production process or generated during equipment maintenance in the production process are discharged. As for the drainage rate, the aqueous solution containing nitrogen components discharged from the washing step accounts for 1 to 10% by weight.

  According to the studies by the present inventors, when waste water containing an aqueous surfactant solution, which accounts for 80% by weight of the total amount of waste water discharged from the toner manufacturing process, and waste water containing nitrogen components are mixed, Although the mechanism is not well understood, due to the action of the surfactant, the settling time in the coagulation sedimentation process becomes longer, and the amount of the inorganic coagulant used for coagulation sedimentation, such as ferric chloride, increases. As a result, the amount of the aggregated precipitate, that is, a large amount of sludge to be processed as industrial waste is generated. This is because a certain amount of ferric chloride used as the inorganic flocculant reacts with the surfactant contained in the waste water to neutralize the charge, thereby inhibiting the action as the flocculant.

  That is, as a result of intensive studies, the present inventor can remove the nitrogen component in the wastewater containing the nitrogen component by anaerobic treatment, thereby removing the nitrogen component present in the water. Since the amount of the inorganic flocculant necessary for the precipitation can be reduced, it has been found that the object of the present invention is achieved, and the present invention has been completed.

[Wastewater treatment method]
The waste water treatment method of the present embodiment will be described with reference to the drawings.

  FIG. 1 shows a wastewater treatment method according to the embodiment, and FIG. 2 shows a conventional wastewater treatment method.

  In FIG. 1, wastewater containing at least a nitrogen component is first subjected to a coagulation sedimentation process or a pressurized flotation process. Hereinafter, the nitrogen component removal process from the wastewater will be described with an example of the coagulation sedimentation treatment.

  In the coagulation sedimentation treatment, first, ferric chloride, which is an inorganic coagulant, is added to the wastewater in the reaction tank to generate floc. This flock contains mainly pigments and waxes. Next, in the flocculation tank, a polymer flocculant is added, and flocs generated with the inorganic flocculant grow. Finally, the precipitated floc is removed in the settling tank. In this coagulation sedimentation process, components other than the nitrogen component are removed.

  Next, after removing the floc, an anaerobic treatment is performed to remove the nitrogen component. Here, the nitrogen component removed from the waste water is mainly decomposed into ammonia, and then reduced and removed as nitrogen. Similarly, nitric acid used for washing is removed after being reduced to nitrogen. In addition, the removal of the nitrogen component from the wastewater is to more strictly suppress eutrophication due to the wastewater.

  And after each above-mentioned process is implemented, it is discharged to a river etc. On the other hand, the precipitate (floc) after coagulation sedimentation is processed as sludge of industrial waste through a sludge dewatering process.

  As the flocculant used in this wastewater treatment facility, an inorganic flocculant and an organic flocculant are used. As the inorganic flocculant, for example, aluminum sulfate, ferric chloride, polyaluminum chloride and the like are used. The amount of the inorganic flocculant added is about 500 to 5000 mg / L with respect to the amount of drainage. However, the inorganic flocculant is not necessarily limited to these. Furthermore, for growing flocs, for example, an acrylamide anionic flocculant can be used as the polymer flocculant. As addition amount, it is about 0.5-5 mg / L with respect to the amount of drainage. The polymer flocculant is not necessarily limited to acrylamide anionic flocculants, and other anionic flocculants, cationic flocculants, and nonionic flocculants can be used. Moreover, you may use combining these.

  Further, the pressure levitation process is performed as follows. First, ferric chloride, an inorganic flocculant, is added to the waste water in the reaction tank to produce flocs, and then a polymer flocculant is added to grow the flocs produced by the inorganic flocculants. . Thereafter, in the pressurized levitation tank, the floc is adsorbed on the surface of the bubbles introduced into the tank, and the floc floating on the surface of the tank is removed.

  By performing the anaerobic treatment of the present embodiment after the above-described coagulation sedimentation treatment or pressure levitation treatment, the sludge generation amount and the nitrogen component removability are improved as described later. A methane fermentation method is used as the anaerobic treatment of the present embodiment. This method is a method of reducing and decomposing to methane and carbon dioxide by the action of anaerobic bacteria. As anaerobic bacteria, for example, methanogenic bacteria are suitable, and examples of methanogenic bacteria include methanosari sodium / flagellum NY-218, methanoscicin / alkaline filler NY-728, and the like.

  The anaerobic treatment described above decomposes nitrogen components in wastewater (mainly contained in latex), mainly ammonia, by the following mechanism.

  Nitrogen contained in the organic matter in the wastewater is decomposed into lower fatty acids, acetic acid, hydrogen, etc. via higher fatty acids and amino acids by hydrolysis and fermentation with the involvement of anaerobic bacteria. It is reductively decomposed into methane, ammonia and hydrogen sulfide. The ammonia produced there is nitrified to nitrate ions, and finally reduced to nitrogen without fear of secondary contamination, and released into the atmosphere.

  As a reactor used for the anaerobic treatment, a septic tank, a travis tank, an Imhof tank, a conventional digester tank, and a high-speed digester tank are used, but the reactor is not limited thereto.

  Moreover, the nitrogen component contained in the waste water is measured according to “JIS K 0102 45.1”. That is, sodium hydroxide is added to the waste water and distilled to remove ammonium ions and the like, and then a Devarda alloy is added to the remaining liquid to reduce nitrate ions and nitrite ions to generate ammonia. This is distilled and quantified by indophenol blue absorptiometry to determine the amount of nitrogen corresponding to nitrate ion and nitrite ion. Separately, drain water, add sulfuric acid, potassium sulfate and copper sulfate and heat to convert organic nitrogen to ammonium ions, then distill with alkali and distill together with ammonia generated from the ammonium ions originally present. The collected ammonium ions are quantified by indophenol blue spectrophotometry, and the amounts of nitrogen corresponding to organic nitrogen and ammonium ions are determined. The sum of both is total nitrogen.

  In the present embodiment, the content of the nitrogen component contained in the wastewater that can be removed from the wastewater is 1 mg / L to 1000 mg / L. In the anaerobic treatment, the methane fermentation method treatment is performed in the present embodiment, but the present invention is not limited to this.

In addition, the amount of anaerobic bacteria added to the above-mentioned nitrogen component amount of 1 mg / L is about 3 g / L ( ³ kg per 1 m ³ tank), more specifically, although the size of the tank is taken into consideration. It is about 0.5 g / L to 5 g / L.

  In the conventional wastewater treatment of FIG. 2, only the coagulation sedimentation treatment or the pressure levitation treatment is performed, and then discharged into a river or the like. On the other hand, the precipitate (sludge) after the coagulation sedimentation is processed as sludge of industrial waste through a sludge dehydration process.

  Next, the present invention will be described more specifically with reference to Examples and Comparative Examples.

  In the toner of the present invention, the specific molecular weight distribution is obtained under the following conditions. GPC uses “HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation)”, and the column uses two “TSKgel, SuperHM-H (6.0 mm ID × 15 cm, manufactured by Tosoh Corporation)” THF (tetrahydrofuran) was used as an eluent. As experimental conditions, the experiment was performed using a sample concentration of 0.5%, a flow rate of 0.6 ml / min, a sample injection amount of 10 μl, a measurement temperature of 40 ° C., and an IR detector. The calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”. ”,“ F-4 ”,“ F-40 ”,“ F-128 ”, and“ F-700 ”.

  Hereinafter, production examples of the electrostatic charge developing toner used in this example and the comparative example will be shown.

[Toner Production Example 1]
<First step>
--Preparation of dispersion (1)-
Styrene 320 parts by weight n-butyl acrylate 80 parts by weight Acrylic acid 10 parts by weight Dodecanethiol 10 parts by weight

  420 parts by weight of this solution, 6 parts by weight of a nonionic surfactant (manufactured by Sanyo Kasei Co., Ltd., Nonipol 400), and 10 parts by weight of an anionic surfactant (manufactured by Daiichi Pharmaceutical Co., Ltd., Neogen R) are added to 550 ion-exchanged water. The solution dissolved in parts by weight was placed in a flask to disperse and emulsify, and 50 parts by weight of ion-exchanged water in which 4 parts by weight of ammonium persulfate was dissolved was added while slowly stirring and mixing for 10 minutes. Then, after fully replacing the inside of the flask with nitrogen, the system was heated with an oil bath until the temperature reached 70 ° C. while stirring, and emulsion polymerization was continued as it was for 5 hours to obtain a resin fine particle dispersion A-1.

The latex obtained with the resin fine particle dispersion A-1 was 155 nm when the volume average particle diameter (D ₅₀ ) of the resin fine particles was measured with a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.). When the glass transition point of the resin was measured at a heating rate of 10 ° C./min using a differential scanning calorimeter (DSC-50, manufactured by Shimadzu Corporation), it was 54 ° C. and the weight average molecular weight was 33,000. It was.

-Preparation of colorant dispersion (1)-
Carbon black (Mogal L: manufactured by Cabot) 60 parts by weight Nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) 6 parts by weight Ion-exchanged water A colorant dispersion (1), which is stirred for 10 minutes using Lux T50 (manufactured by IKA) and then dispersed with an optimizer to disperse colorant (carbon black) particles having a volume average particle diameter of 250 nm. ) Was prepared.

-Preparation of release agent dispersion (1)-
50 parts by weight of paraffin wax (manufactured by Nippon Seiwa Co., Ltd .: HNP0190, melting point 85 ° C.)
Cationic surfactant ... 5 parts by weight (manufactured by Kao Corporation: Sanisol B50)
Ion-exchanged water ... 200 parts by weight

  The above was heated to 95 ° C. and dispersed using a homogenizer (IKA: Ultra Turrax T50), and then dispersed with a pressure discharge homogenizer to disperse a release agent having an average particle size of 550 nm. A release agent dispersion (1) was prepared.

--Preparation of aggregated particles--
Dispersion liquid (1) ... 200 parts by weight Colorant dispersion liquid (1) ... 50 parts by weight Release agent dispersion liquid (1) ... 50 parts by weight cationic surfactant 1.5 parts by weight (manufactured by Kao Corporation: Sanisol B50)

The above was mixed and dispersed in a round stainless steel flask using a homogenizer (manufactured by IKA: Ultra Turrax T50), and then heated to 48 ° C. while stirring the inside of the flask in an oil bath for heating. After maintaining at 48 ° C. for 30 minutes, observation with an optical microscope confirmed that aggregated particles (volume: 95 cm ³ ) having an average particle diameter of about 5 μm were formed.

--Preparation of adhered particles--
Here, 60 parts by weight of the dispersion liquid (1) as the resin-containing fine particle dispersion liquid was gradually added. The volume of the resin particles contained in the dispersion (1) is (25 cm ³ ). And the temperature of the heating oil bath was raised to 50 degreeC, and was hold | maintained for 1 hour. When observed with an optical microscope, it was confirmed that adhered particles having an average particle diameter of about 5.7 μm were formed.

<Third step>
Thereafter, after adding 3 parts by weight of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC), the stainless steel flask was sealed, and stirring was continued using a magnetic seal. Heated to 0 ° C. and held for 3 hours. Then, after cooling, the reaction product was filtered, washed thoroughly with ion exchange water, and then dried to obtain an electrostatic image developing toner.

  The content of the nitrogen component in the waste water A discharged during the production of Production Example 1 was measured according to the above-mentioned “JIS K 0102 45.1” and was 1 mg / L.

[Toner Production Example 2]
<First step>
--Preparation of dispersion (2)-
Styrene 320 parts by weight n-butyl acrylate 80 parts by weight Acrylic acid 10 parts by weight Dodecanethiol 5 parts by weight

  434 parts by weight of this solution, 6 parts by weight of a nonionic surfactant (manufactured by Sanyo Kasei Co., Ltd., Nonipol 400), and 10 parts by weight of an anionic surfactant (manufactured by Daiichi Pharmaceutical Co., Ltd., Neogen R) are added to 550 ion-exchanged water. The solution dissolved in parts by weight was placed in a flask to disperse and emulsify, and 50 parts by weight of ion-exchanged water in which 16 parts by weight of ammonium persulfate was dissolved was added while slowly stirring and mixing for 10 minutes. Thereafter, the flask was sufficiently replaced with nitrogen and then heated with stirring in an oil bath until the temperature in the system reached 70 ° C., and emulsion polymerization was continued for 5 hours to obtain a resin fine particle dispersion A-2.

The latex obtained with the resin fine particle dispersion A-2 was 155 nm when the volume average particle diameter (D ₅₀ ) of the resin fine particles was measured with a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.). The glass transition point of the resin was measured at a temperature rising rate of 10 ° C./min using a differential scanning calorimeter (DSC-50, manufactured by Shimadzu Seisakusho Co., Ltd.). It was 31000.

--Preparation of aggregated particles--
Dispersion (2) ... 200 parts by weight Colorant dispersion (1) ... 50 parts by weight Release agent dispersion (1) ... ··· 70 parts by weight Cationic surfactant ······ 2.0 parts by weight (manufactured by Kao Corporation: Sanisol B50)

The above was mixed and dispersed in a round stainless steel flask using a homogenizer (manufactured by IKA: Ultra Turrax T50), and then heated to 48 ° C. while stirring the inside of the flask in an oil bath for heating. After holding for 30 minutes at 48 ° C., agglomerated particles (volume: 95cm ³⁾ the average particle size to be observed with an optical microscope of about 5.2μm it was confirmed to be formed.

--Preparation of adhered particles--
Here, 60 parts of dispersion (2) as a resin-containing fine particle dispersion was gently added. In addition, the volume of the resin particle contained in the dispersion liquid (2) is (25 cm ³ ). And the temperature of the heating oil bath was raised to 50 degreeC, and was hold | maintained for 1 hour. When observed with an optical microscope, it was confirmed that adhered particles having an average particle diameter of about 5.7 μm were formed.

<Third step>
Thereafter, after adding 3 parts by weight of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC), the stainless steel flask was sealed, and stirring was continued using a magnetic seal. Heated to 0 ° C. and held for 3 hours. After cooling, the reaction product was filtered, sufficiently washed with ion exchange water, and then dried to obtain an electrostatic charge image developing toner.

  Content of the nitrogen component in the waste_water | drain B discharged | emitted in the case of manufacture of the said manufacture example 1 was measured according to "JIS K 0102 45.1" mentioned above, and was 3.9 mg / L.

[Composition of drainage A]
Wastewater A is wastewater that is actually discharged from the factory by the production of Production Example 1 and includes at least a nitrogen component in addition to the pigment dispersion, wax dispersion, aqueous emulsion, and aqueous surfactant solution. Wastewater. The main composition of the drainage A is shown below.
Nitrogen component: 0.06 parts by weight Anionic surfactant ("Neogen SC" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 0.08 parts by weight Latex polymer: 0.04 parts by weight Colorant: 0.16 parts by weight wax ( “Polywax 725” manufactured by Toyo Petrolite Co., Ltd.): 0.12 parts by weight Water: 999.5 parts by weight

[Composition of drainage B]
Waste water B is waste water that is actually discharged from the factory by the production of Production Example 2 and includes at least a nitrogen component in addition to the pigment dispersion, wax dispersion, aqueous emulsion, and aqueous surfactant. Wastewater. The main composition of the drainage A is shown below.

Nitrogen component: 0.23 parts by weight Anionic surfactant ("Neogen SC" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 0.32 parts by weight Latex polymer: 0.15 parts by weight Colorant: 0.61 parts by weight wax ( “Polywax 725” manufactured by Toyo Petrolite Co., Ltd.): 0.5 parts by weight Water: 998.2 parts by weight

Example 1
Wastewater A treated wastewater A having a solid content concentration of 0.5 wt% was treated using the wastewater treatment facility shown in FIG. For the coagulation sedimentation treatment, 1000 mg / L of an inorganic flocculant (ferric chloride) and 1 mg / L of a polymer flocculant (acrylamide polymer flocculant: Hymolock SS-100, manufactured by Hymo Co., Ltd.) are added, and 18 m ^The wastewater treatment facility having ³ coagulation sedimentation tanks was processed in batch mode. Anaerobic treatment was performed in a 100 m ³ high-speed digester in 5 hours. As a result, the sludge generation amount is 1.1 g / L, the treated waste water is transparent without coloration, and the total nitrogen amount (total of ammonia nitrogen, nitrate nitrogen, etc.) is the above-mentioned “JIS K 0102 45”. .1 "and <1.0 mg / L, the processability was not a problem.

(Example 2)
Wastewater B treatable wastewater B having a solid content concentration of 1.8 wt% was treated in the same manner as in Example 1 using the wastewater treatment facility shown in FIG. At this time, 2000 mg / L of an inorganic flocculant (ferric chloride) and 2 mg / L of a polymer flocculant (acrylamide polymer flocculant: Hymolock SS-100) are added, and an 18 m ³ coagulation sedimentation tank is provided. The wastewater treatment facility was used for batch processing. Anaerobic treatment was performed in a 100 m ³ high-speed digester in 5 hours. As a result, the sludge generation amount is 74 g / L, the treated waste water is transparent without coloration, and the total nitrogen amount is measured in accordance with the above-mentioned “JIS K 0102 45.1”, <1.0 mg / L And there was no problem with the processability.

(Example 3)
Wastewater A treated wastewater A having a solid content concentration of 0.05 wt% was treated using the wastewater treatment facility shown in FIG. For the pressure levitation treatment, 1000 mg / L of an inorganic flocculant (ferric chloride) and 1 mg / L of a polymer flocculant (acrylamide polymer flocculant: Hymolock SS-100, manufactured by Hymo Co.) are added, The wastewater treatment facility having a pressurized floating tank of 18 m ³ was treated in a batch manner. Anaerobic treatment was performed in a 100 m ³ high-speed digester in 5 hours. As a result, the amount of sludge generated was 1.1 g / L, the treated waste water was transparent without coloration, and the total nitrogen amount was measured according to the above-mentioned “JIS K 0102 45.1”, <1.0 mg There was no problem in the processability at / L.

Example 4
Wastewater B treatable wastewater B having a solid content concentration of 1.8 wt% was treated in the same manner as in Example 1 using the wastewater treatment facility shown in FIG. At this time, 2000 mg / L of an inorganic flocculant (ferric chloride) and 2 mg / L of a polymer flocculant (acrylamide polymer flocculant: Hymolock SS-100) were added, and a 18 m ³ pressurized floating tank was added. The wastewater treatment facility has batch processing. Anaerobic treatment is a fast digester of 100 m ^3, was treated at 5 hours. As a result, the sludge generation amount is 74 g / L, the treated waste water is transparent without coloration, and the total nitrogen amount is measured in accordance with the above-mentioned “JIS K 0102 45.1”, <1.0 mg / L And there was no problem with the processability.

(Comparative Example 1)
Wastewater A Treated wastewater A having a solid content concentration of 0.01 wt% was treated using the wastewater treatment facility of FIG. At this time, 5000 mg / L of an inorganic flocculant (ferric chloride) and 1 mg / L of a polymer flocculant (acrylamide polymer flocculant: Hymolock SS-100) are added, and an 18 m ³ coagulation sedimentation tank is provided. The wastewater treatment facility was treated in a batch manner for 7 hours. As a result, the sludge generation amount was 5.1 g / L, and about 5 times as much sludge was generated as in Example 1. The total nitrogen amount was measured according to the above-mentioned “JIS K 0102 45.1”, and <1 There was no problem in processability at 0.0 mg / L.

(Comparative Example 2)
Wastewater B Treated wastewater B having a solid content concentration of 5 wt% was treated using the wastewater treatment facility of FIG. At this time, 5000 mg / L of an inorganic flocculant (ferric chloride) and 2 mg / L of a polymer flocculant (acrylamide polymer flocculant: Hymolock SS-100) are added, and an 18 m ³ coagulation sedimentation tank is provided. The wastewater treatment facility was treated in a batch manner for 7 hours. As a result, the amount of sludge generated was 185 g / L, and about 2.5 times as much sludge was generated as in Example 2. In addition, the waste water remained colored with pigments or the like after the coagulation sedimentation treatment, and the total nitrogen amount was measured in accordance with the above-mentioned “JIS K 0102 45.1”, and the processability was poor at 10 mg / L.

  The wastewater treatment method of the present invention is particularly useful for wastewater treatment discharged during the production of toner for developing electrostatic charge, but is also useful for industrial wastewater treatment having substances having different organic and inorganic characteristics.

It is a figure explaining the waste water treatment method concerning an embodiment. It is a figure explaining the conventional waste water treatment method.

Claims (2)

A wastewater treatment method for treating wastewater containing at least a surfactant and a nitrogen component generated from a production process of an electrostatic charge image developing toner,
A step of coagulating and precipitating the waste water containing the surfactant and nitrogen component generated from the manufacturing process , and a step of removing the nitrogen component by anaerobic treatment of the waste water after the coagulating and precipitating treatment. A wastewater treatment method characterized by that. The waste water treatment method according to claim 1,
A method for treating waste water, wherein the step of removing the nitrogen component comprises a methane fermentation method.

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