JP5733677B2 - Wastewater treatment agent - Google Patents

Description

  The present invention relates to a wastewater treatment agent, and more particularly, to a wastewater treatment agent that exhibits an excellent flocculation effect for various wastewaters and is easy to handle.

  Common in industrial wastewater generated in automobile manufacturing plants, steel mills, pulp and paper manufacturing, cleaning, gravel industry, other chemical factories, sewage and human waste treatment plants, and coagulation treatment of biologically treated water In addition, after adding an inorganic flocculant such as sulfuric acid band (hereinafter referred to as “band”), polyaluminum chloride (hereinafter referred to as “PAC”) and the like, a polymer flocculant is further added to generate an aggregate floc, Or the method of processing by the coagulation flotation method is employ | adopted. The purified treated water is generally discharged into rivers and sewage.

  By the way, with respect to stricter regulations on the quality of discharged water, the quality of water has been improved by improving treatment equipment and wastewater treatment methods, and it has become essential to increase the amount of inorganic flocculant used. However, when the amount of the inorganic flocculant used is increased, the chemical cost is increased, the amount of generated sludge is increased, and the generated sludge treatment cost is increased. Further, even if the strength of the inorganic flocculant is sufficient, the SS of the treated water can be satisfied, but there are many cases where a sufficiently satisfactory effect in COD, turbidity, chromaticity and the like cannot be obtained.

Under the circumstances as described above, application of an organic coagulant, which is a kind of water-soluble cationic polymer, has been promoted for the purpose of reducing the amount of inorganic flocculant while maintaining and improving the quality of treated water. However, when an organic coagulant is applied, an inorganic coagulant, an organic coagulant, and a polymer coagulant are used, so that a new apparatus for the organic coagulant is installed and operation management becomes complicated. There is a problem. In particular, since the addition ratio of the inorganic flocculant and the organic coagulant varies depending on the type of wastewater, operation management is further complicated.

Under the circumstances as described above, a one-component waste water treatment agent containing an inorganic flocculant and an organic coagulant has been proposed. For example, a treatment method for dyeing wastewater using a drug containing polyaluminum chloride (PAC) and diallyldimethylammonium chloride polymer (DADMAC) has been proposed (Patent Document 1). Moreover, the processing method of the civil engineering mud water which uses the mixture of PAC and DADMAC is proposed (patent document 2). Furthermore, a flocculant in which polyallylamine and a chlorine compound of iron or aluminum are blended has been proposed (Patent Document 3). This flocculant is said to exhibit an excellent effect particularly in the flocculation treatment of dyeing wastewater.

  However, although all of the above-mentioned drugs are easy to use and have some effects, they cannot be said to be sufficiently satisfactory in terms of aggregation performance, processing cost, and the like.

JP-A-6-182350 JP-A-6-182353 JP-A-7-313804

  The present invention has been made in view of the above circumstances, and its purpose is to provide a wastewater treatment agent that exhibits an excellent coagulation effect with respect to various types of wastewater, is easy to handle, reduces the amount of chemicals added, and can reduce treatment costs. It is to provide.

  As a result of extensive studies, the inventor of the present invention proposed the above-mentioned proposal in the prior art by blending a specific water-soluble polymer mainly composed of a dialkylaminoalkyl methacrylate methyl chloride quaternary salt and an inorganic flocculant. The present inventors have obtained knowledge that a wastewater treatment agent having a better coagulation effect and a better quality of treated water than a wastewater treatment agent can be obtained, leading to the present invention.

That is, the gist of the present invention is that an intrinsic viscosity of 0.01 to 4.0 and a dialkylaminoalkyl methacrylate methyl chloride quaternary salt in a proportion exceeding 90% by weight and a water-soluble polymer not containing (meth) acrylamide and iron or The wastewater treatment agent is characterized by comprising an aluminum-based inorganic flocculant, and the mixing ratio of the water-soluble polymer and the inorganic flocculant is 0.05 / 100 to 10/100 as a weight ratio.

  The wastewater treatment agent of the present invention has the same handleability as that of generally marketed inorganic flocculants, exhibits excellent flocculation effects on various wastewaters, and reduces the amount of chemicals added to reduce wastewater treatment costs. it can.

Hereinafter, the present invention will be described in detail.

  One component of the wastewater treatment agent of the present invention is a water-soluble polymer, which is a polymer mainly composed of a dialkylaminoalkyl methacrylate methyl chloride quaternary salt and does not contain a (meth) acrylamide monomer.

  As the dialkylaminoalkyl methacrylate methyl chloride quaternary salt, dimethylaminoethyl methacrylate methyl chloride quaternary salt represented by the following chemical formula (I) is preferable.

  As the water-soluble polymer used in the present invention, a homopolymer of dimethylaminoethyl methacrylate methyl chloride quaternary salt is preferable, but other monomers are used as long as they do not adversely affect the setting performance, solution stability, handleability, and the like. The body may be copolymerized.

  Examples of the copolymerizable monomer include monomers other than (meth) acrylamide monomers, such as dimethylaminoethyl methacrylate sulfate, dimethylaminoethyl methacrylate benzyl chloride quaternary salt, dimethylaminoethyl acrylate methyl chloride quaternary. Examples thereof include cationic monomers such as salts and nonionic monomers such as acrylonitrile and methyl methacrylate. The copolymerization ratio with other copolymerizable monomers is not particularly limited, but is preferably 10% by weight or less.

  In addition, the polymer which copolymerized (meth) acrylamide has the fault of thickening with time, when mix | blending with an inorganic flocculant. The reason is estimated to be due to the cross-linking reaction over time under strong acidity. In particular, when blended with a sulfate-based inorganic flocculant, the viscosity increase tends to be intense.

  The intrinsic viscosity of the water-soluble polymer used in the present invention is 0.01 to 4.0, preferably 0.03 to 2.5. The intrinsic viscosity means a value measured at a temperature of 30 ° C. in a 1N sodium nitrate aqueous solution according to a normal method. When the intrinsic viscosity is outside the above range, when used as a wastewater treatment agent, the cohesiveness, turbidity and chromaticity of treated water are inferior.

  The shape of the water-soluble polymer used in the present invention is not particularly limited, and any shape of powder and liquid may be used. The polymerization method includes precipitation polymerization, bulk polymerization, dispersion polymerization, aqueous solution polymerization and the like, but is not particularly limited. As an example, a manufacturing method using an aqueous solution polymerization method will be described below.

  First, a predetermined amount of dimethylaminoethyl methacrylate methyl chloride quaternary salt and ion-exchanged water are weighed, adjusted to a predetermined pH and temperature, and then charged into an airtight container that can be sealed. Next, the dissolved oxygen is replaced with nitrogen gas, and chemicals such as a polymerization initiator and a continuous transfer agent are added. As the polymerization initiator, known general azo initiators, redox initiators, and the like can be used. As the polymerization proceeds, the polymerization temperature rises, but after the temperature reaches its peak, it is aged for 1 hour, and the polymer gel is taken out from the reaction vessel. The polymer gel is chopped with a meat chopper or the like and dried at a temperature of 80 ° C. with a blow dryer. The dried polymer is pulverized to a particle size of about 0.5 to 1 mm to obtain a powdered water-soluble polymer.

  Another component of the wastewater treatment agent of the present invention is an iron or aluminum inorganic flocculant. Examples of the aluminum-based inorganic flocculant include band, PAC, and aluminum chloride. Examples of the iron-based inorganic flocculant include ferric chloride and polyiron sulfate. The inorganic flocculant may be chloride or sulfate, but chloride is superior in handleability because of its lower viscosity when an organic coagulant is blended.

  The mixing ratio of the water-soluble polymer and the inorganic flocculant is 0.05 / 100 to 10/100, preferably 0.1 / 100 to 5/100, as a weight ratio. When the blending ratio is less than the above range, the turbidity and chromaticity of the treated water are almost the same as when the inorganic flocculant is used alone, and the effect of blending the water-soluble polymer is not exhibited. Moreover, when a mixture ratio exceeds said range, aggregability will deteriorate and turbidity and chromaticity will deteriorate. Furthermore, the viscosity of the wastewater treatment agent is high and the handleability is also deteriorated.

  An example of the method for preparing the wastewater treatment agent of the present invention is as follows.

1. When water-soluble polymer is powder:
Water and an inorganic flocculant are added to a container equipped with a stirrer, and a water-soluble polymer powder is added while stirring. The mixture is stirred for about 30 to 60 minutes to dissolve the inorganic flocculant and the water-soluble polymer in water. An inventive wastewater treatment agent is obtained.

2. If the water-soluble polymer is liquid:
The wastewater treatment agent of the present invention is obtained in the same manner as above. However, when the shape is liquid, since the water-soluble polymer is easily dissolved in the inorganic flocculant, the stirring time is short, and a few minutes is sufficient.

In addition, when the container, lorry, etc. are filled with the inorganic flocculant, the liquid water-soluble polymer is put in the container, lorry, etc. in advance, and then the inorganic flocculant is filled with the wastewater treatment agent of the present invention. It can also be prepared. In this case, the inorganic flocculant may be filled first.
It is also possible to put into a container after filling. Further, when the inorganic flocculant is introduced into the customer storage tank, it is also possible to introduce and mix a liquid water-soluble polymer.

  The wastewater treatment agent of the present invention may be used in the same manner as a general wastewater treatment method using an inorganic flocculant. Specifically, after adding and mixing the wastewater treatment agent of the present invention to wastewater, the pH is adjusted as necessary, and a polymer flocculant is added to form agglomeration flocs, which are solid-liquid by precipitation treatment or flotation treatment. Separate to obtain treated water. The polymer flocculant may be any of conventionally known anionic, nonionic, cationic and amphoteric types. For example, examples of the anionic polymer flocculant include sodium polyacrylate, partial hydrolyzate of polyacrylamide, copolymer of acrylamide and sodium acrylate, polymer of 2-acrylamide-2methylpropanesulfonic acid, or acrylamide. And the like, and the like. Examples of nonionic polymer flocculants include polymers of acrylamide or copolymers with other nonionic monomers.

  The wastewater treatment agent of the present invention is used for industrial wastewater generated in automobile manufacturing factories, steel mills, paper pulp manufacturing industry, cleaning, gravel industry, other chemical factories, sewage / human waste treatment plant return water, biological treatment water. It is widely used in place of conventional inorganic flocculants in agglomeration treatment.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to a following example at all unless the summary is exceeded. In addition, each measuring method employ | adopted in the following examples is as follows.

(1) Intrinsic viscosity of the polymer flocculant:
Intrinsic viscosity was measured based on a conventional method using a Ubbelohde dilution type capillary viscometer in a 1N sodium nitrate aqueous solution at a temperature of 30 ° C. (edited by the Society of Polymer Science, “New Edition Polymer Dictionary”, Asakura Shoten, p. 107).

(2) Flock diameter:
The average floc diameter of the aggregated floc was measured visually.

(3) Settling time:
A predetermined amount of the polymer flocculant is added, and after stirring for a predetermined time, stirring is stopped. And the time until the produced | generated aggregation floc settles in the bottom of a 500 ml beaker was measured.

(4) Supernatant turbidity (SS):
After measuring the sedimentation time, the sample was allowed to stand for 2 minutes, and treated water was collected from a depth of 3 cm from the surface and measured. Measured based on the factory wastewater test method JIS K 0102.

(5) Supernatant chromaticity:
After measuring the sedimentation time, the sample was allowed to stand for 2 minutes, and treated water was collected from a depth of 3 cm from the surface and measured. Based on the factory wastewater test method JIS K 0102, the measurement was performed by the transmitted light measurement method. The measured value was shown by transmittance (%) at 420 nm.

Test Example 1:
It was investigated whether each polymer dissolved in various inorganic flocculants. The polymers used are shown in Table 1.
The test results are shown in Table 2.

  In Table 1, diallyldimethylammonium chloride-based polymer is manufactured by Daianitrix (table name CHP795M), alkylamine / epichlorohydrin condensate is manufactured by Daianitrix (table name K601), and dicyandiamide-based polymer is manufactured by Daianitrix (table). Product name K415), polyethyleneimine used by Daianitrix (table name K409), and polyvinylamidine used by Daianitrix (table name KP7000).

  The solubility test methods shown in Table 2 are as follows.

1. If the polymer is a powder:
Weigh 500 g of the inorganic flocculant into a 500 ml glass beaker. While stirring, 5 g of polymer is added and dissolved by stirring for 60 minutes. After stirring for 60 minutes, the total amount of the liquid is opened on a 100-mesh sieve and the weight of insoluble matter on the sieve is measured. When the weight of the insoluble material is less than 10 g, “O” (dissolved) and 10 g or more are represented as “X” (dissolvable).

2. If the polymer is liquid:
Weigh 500 g of the inorganic flocculant into a 500 ml glass beaker. 5 g of the polymer is added in terms of pure content and stirred for 3 minutes. If the insoluble matter does not precipitate visually, it is indicated as “◯” (dissolved), and if it is precipitated, it is indicated as “x” (not soluble).

  As shown in Table 2, the dimethylaminoethyl methacrylate methyl chloride quaternary salt water-soluble polymer used in the present invention is dissolved in an iron-based or aluminum-based inorganic flocculant. However, even a dimethylaminoethyl methacrylate methyl chloride quaternary salt polymer cannot dissolve in a sulfate band which is a sulfate inorganic flocculant if its intrinsic viscosity is higher than the range specified in the present invention. In addition, a polymer obtained by copolymerizing AAm, a dicyandiamide-based polymer polyethyleneimine, and polyvinylamidine have poor solubility.

Test Example 2 (Wastewater treatment agent stability test):
A wastewater treatment agent prepared by mixing a polymer and an inorganic flocculant was stored in a dark place at room temperature, a change in viscosity over time was measured, and the solution stability was investigated. The solution viscosity was measured using B-type viscosity manufactured by Tokyo Keiki Co., Ltd. The results are shown in Table 3.

  As shown in Test Examples 2-1 to 2-10 in Table 3, the water-soluble polymer used in the present invention has a viscosity increase rate of about 10% after 4 weeks regardless of the type of the inorganic flocculant and is stable. doing. As shown in Test Examples 2-11 to 2-12, even if the blending ratio is changed within the range defined in the present invention, the viscosity increase rate after 4 weeks is about 10% and is stable.

  As shown in Comparative Test Example 2-1 and Comparative Test Example 2-2, even if it is a dimethylaminoethyl methacrylate methyl chloride quaternary salt polymer, if the intrinsic viscosity is higher than the range specified in the present invention, the viscosity increase rate Is high and uneasy. Moreover, as shown in Comparative Test Example 2-3 and Comparative Test Example 2-4, when using a polymer containing AAm and when using a polymer having a different raw material composition, the viscosity increase rate is high and uneasy. . As shown in Comparative Test Example 2-5, when a DADMAC polymer was used, the rate of increase in viscosity after 4 weeks was 25% in combination with PAC and 56% in combination with sulfate band. , Greatly increase the viscosity.

Examples 1-5 and Comparative Examples 1-7:
A mop and mat washing waste water from a leasing company for A dust control products was collected and subjected to a coagulation test. The properties of the wastewater were pH = 8.9, SS = 350 mg / l, and transmittance at 420 nm = 2%.

  First, 500 ml of waste water was collected in a 500 ml beaker, various waste water treatment agents or PAC were added, and the mixture was stirred and mixed at a rotation speed of 150 rpm for 1 minute, and then adjusted to pH 5.5. Next, an anionic polymer flocculant A1 (manufactured by Daianitrix, name of product AP741B) was added as a polymer flocculant, and the mixture was further stirred for 1 minute at a rotation speed of 100 rpm to form an aggregate floc. The floc diameter, the sedimentation time of the aggregated floc, the turbidity and chromaticity of the treated water were measured. The results are shown in Table 4.

  As shown in Examples 1 to 5, all of the wastewater treatment agents of the present invention have good cohesiveness and can provide treated water with good turbidity and chromaticity.

  As shown in Comparative Examples 1 and 2, when the intrinsic viscosity is higher than the range specified in the present invention even with a dimethylaminoethyl methacrylate methyl chloride quaternary salt polymer, the aggregated floc diameter and sedimentation time are not a problem. The turbidity and chromaticity of treated water are significantly inferior to those of the examples, and in particular, inferior to Comparative Example 7 using PAC in chromaticity.

  As shown in Comparative Examples 3 and 4, when a polymer containing AAm or a polymer having a different raw material composition is used, there is no problem with the aggregated floc diameter and sedimentation time, but the turbidity and chromaticity of the treated water are not affected. Much worse than the example.

  As shown in Comparative Examples 5 and 6, when DADMAC or an alkylamine / epichlorohydrin condensate was used, the results were better than Comparative Example 7 using PAC, but the chromaticity was higher than that of Examples. Is significantly inferior.

  As shown in Comparative Example 7, when PAC is used, the turbidity and chromaticity of the treated water are significantly inferior to those of Examples.

Examples 6-12 and Comparative Examples 8-15:
The agglomeration test was carried out using the return water from N wastewater treatment plant (centrifugal concentrate of excess sludge). The properties of the wastewater were pH = 6.9 and turbidity (NTU) = 287.

  First, 500 ml of waste water was collected in a 500 ml beaker, various waste water treatment agents or PAC were added, and the mixture was stirred and mixed at a rotation speed of 150 rpm for 1 minute, and then adjusted to pH 5.5. Next, an anionic polymer flocculant A2 (manufactured by Daianitrix Co., Ltd., product name AP120C) was added as a polymer flocculant, and further stirred for 1 minute at a rotation speed of 100 rpm to form a floc floc. The floc diameter, the sedimentation time of the aggregated floc, and the turbidity of the treated water were measured. The results are shown in Table 5.

  As shown in Examples 6 to 9, all of the wastewater treatment agents (formulation ratio: 1/100) of the present invention have good cohesiveness and turbidity of treated water. In addition, as shown in Examples 10 to 12, the wastewater treatment agent (mixing ratio: 0.1 / 100 to 2/100) of the present invention has good cohesiveness and turbidity of treated water. . Any of the above blending ratios is superior to Comparative Example 7 using PAC, but the blending ratios of 0.1 or less and 2 or more are comparable to those of Comparative Example 5 using DADMAC.

  As shown in Comparative Examples 8 and 9, even if it is a dimethylaminoethyl methacrylate methyl chloride quaternary salt polymer, if the intrinsic viscosity is higher than the range specified in the present invention, the aggregated floc diameter and sedimentation time are not a problem. The turbidity of treated water is significantly inferior to the examples.

  As shown in Comparative Examples 10 and 11, even when a polymer containing AAm and a polymer having different raw material compositions were used, there was no problem with the aggregated floc diameter and settling time, but the turbidity of the treated water was significantly higher than in the examples. Inferior to

  As shown in Comparative Examples 12 and 13, when DADMAC or an alkylamine / epichlorohydrin condensate was used, the result was better than Comparative Example 7 using PAC, but turbidity compared to Examples. Is inferior.

  As shown in Comparative Example 14, when PAC is used, the turbidity of treated water is significantly inferior compared to the Examples. Moreover, as shown in Comparative Example 15, when the PAC addition amount is increased by 50% and 600 mg / l is added, the turbidity of the treated water is improved as compared with Comparative Example 14, but is inferior to the Examples.

Examples 13-17 and Comparative Examples 16-20:
The coagulation test was carried out using the return water (centrifugal concentrate of excess sludge) from the same N sewage treatment plant as in Examples 6-12.

  First, 500 ml of wastewater was collected in a 500 ml beaker, various wastewater treatment agents or various inorganic flocculants were added, and the mixture was stirred and mixed at a rotation speed of 150 rpm for 1 minute, and then adjusted to pH 5.5. Next, an anionic polymer flocculant A2 (manufactured by Daianitrix Co., Ltd., product name AP120C) was added as a polymer flocculant, and further stirred for 1 minute at a rotation speed of 100 rpm to form a floc floc. The floc diameter, the sedimentation time of the aggregated floc, and the turbidity of the treated water were measured. The results are shown in Table 6.

  As shown in Examples 13 to 15, all of the wastewater treatment agents of the present invention have good cohesiveness and treated water turbidity.

  As shown in Examples 16 and 17, when K2 is used as the water-soluble polymer in the present invention and aluminum chloride (Example 16) or ferric chloride (Example 17) is used as the inorganic flocculant, Also, good results can be obtained in the same manner as the results using sulfuric acid band or PAC.

  As shown in Comparative Example 16, even in the case of a dimethylaminoethyl methacrylate methyl chloride quaternary salt polymer, DADMAC was used as shown in Comparative Example 17 when the intrinsic viscosity was higher than the range specified in the present invention. In this case, the aggregated floc diameter, the sedimentation time, and the turbidity of the treated water are inferior to those of Examples 25 to 27.

  Comparative Example 18 is a case where sulfuric acid band is used, Comparative Example 19 is a case where aluminum chloride is used, and Comparative Example 20 is a case where ferric chloride is used. Compared to Examples 14, 15, and 16 of the wastewater treatment agent containing K2, respectively. In addition, the aggregate floc diameter, the sedimentation time, and the turbidity of the treated water are greatly inferior.

Examples 18-23 and Comparative Examples 21-27:
Coagulation tests were performed using T paper company factory wastewater (machine / DIP mixed wastewater). The properties of the wastewater were pH = 8.4 and turbidity (NTU) = 107.

  First, 500 ml of waste water was collected in a 500 ml beaker, a waste water treatment agent or aluminum chloride was added, and the mixture was stirred and mixed for 1 minute at a rotation speed of 150 rpm. Next, an anionic polymer flocculant A3 (manufactured by Daianitrix, product name AP805C) was added as a polymer flocculant, and the mixture was further stirred for 1 minute at a rotation speed of 100 rpm to form an aggregate floc. The floc diameter, the sedimentation time of the aggregated floc, and the turbidity of the treated water were measured. The results are shown in Table 7.

  As shown in Examples 18 to 20, each of the wastewater treatment agents (formulation ratio 1/100) of the present invention has good cohesiveness and treated water turbidity. As shown in Examples 21 to 23, the wastewater treatment agent (mixing ratio 0.1 / 100 to 2/100) of the present invention has good cohesiveness and treated water turbidity. Any of the above blending ratios is superior to aluminum chloride (Comparative Example 26), DADMAC (Comparative Example 24), and alkylamine / epichlorohydrin condensate (Comparative Example 25).

  As shown in Comparative Examples 21 and 22, when the intrinsic viscosity is higher than the range specified in the present invention even with a dimethylaminoethyl methacrylate methyl chloride quaternary salt polymer, the aggregated floc diameter and sedimentation time are not a problem. The turbidity of treated water is significantly inferior to the examples.

  As shown in Comparative Examples 23 and 24, when a polymer containing AAm and a polymer having a different raw material composition were used, there was no problem with the aggregate floc diameter and the sedimentation time, but the turbidity of the treated water was significantly higher than in the examples. Inferior to

  As shown in Comparative Examples 25 and 26, when DADMAC or an alkylamine / epichlorohydrin condensate was used as a polymer to be blended, the results were better than Comparative Example 26 using aluminum chloride. Compared to turbidity is inferior.

  As shown in Comparative Example 27, when aluminum chloride is used, there is no problem with the aggregate floc diameter and settling time, but the turbidity of the treated water is significantly inferior to that of the example.

Claims (2)

It consists of a water-soluble polymer having an intrinsic viscosity of 0.01 to 4.0 and a methyl chloride quaternary salt of dialkylaminoalkyl methacrylate exceeding 90% by weight and containing no (meth) acrylamide and an iron or aluminum inorganic flocculant. A wastewater treatment agent, wherein the mixing ratio of the water-soluble polymer and the inorganic flocculant is 0.05 / 100 to 10/100 as a weight ratio.   The wastewater treatment agent according to claim 1, wherein the water-soluble polymer is a homopolymer of dimethylaminoethyl methacrylate methyl chloride quaternary salt.