JP2014094365A - Decoloration method for waste water subjected to anaerobic biological treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a decoloration method for waste water including a coloring component from a whisky manufacturing plant or the like in which the amount of coagulated sludge is reduced, and also, running cost is low.SOLUTION: Provided is a decoloration method for waste water subjected to anaerobic biological treatment including: a condensation-primary treatment step in which zero-order treated water obtained by subjecting waste water comprising a coloring component to anaerobic biological treatment is added with polydiallyldimethyl ammonium chloride as a cationic coagulant in a first coagulation tank to form micro flocks of a coloring component; a coagulation-secondary treatment step in which the primarily treated water subjected to the primary treatment step is added with dimethylaminoethyl methacrylate methyl chloride as a cationic flocculant in a second coagulation tank to form a coarse flock in which the micro flocks are aggregated; and a solid-liquid separation step in which the secondary treated water subjected to the secondary treatment step is separated into the coagulated sludge and tertiary treated water in a solid-liquid separation tank.

Description

  The present invention relates to a method for decolorizing wastewater subjected to anaerobic biological treatment. More specifically, the present invention relates to a zero-order treated water obtained by subjecting a distillation residue wastewater containing a coloring component from a whiskey distillation factory to an anaerobic biological treatment, a specific cationic coagulant and a specific cationic coagulation. The present invention relates to a method of decolorizing the waste water by adding agents in order at a specific ratio and effectively aggregating the coloring components to separate and remove the agglomerates from the zero-order treated water.

  In general, distillate wastewater discharged from a liquor manufacturing factory, for example, a whiskey distillation factory, has a high COD concentration and a high phosphorus concentration. The wastewater is subjected to anaerobic biological treatment, and then, if necessary, ammonia and nitrogen components are added. By performing nitrification for removal, COD and BOD can be reduced, but at the same time, the chromaticity of the treated water increases. Therefore, in order not to deteriorate the environment outside the factory, it may be necessary to perform a decoloring process before the treated water is discharged into the river.

Conventionally known decolorization techniques include precipitation by adding flocculants, biological treatment (biological treatment), ozone (O ₃ ) treatment, sodium hypochlorite treatment, electrolysis, etc. The conventional treatment is insufficient in the effect of reducing the chromaticity with respect to the waste water of the distilled liquor factory, and the ozone treatment and the electrolysis require a large initial investment to obtain a sufficient effect of reducing the chromaticity. Moreover, although sodium hypochlorite treatment has a high decoloring effect, it has a high running cost and adversely affects activated sludge treatment. In addition, chlorine is mixed into the treated water, which adversely affects fish in rivers. Therefore, it can be said that precipitation treatment by adding a flocculant is suitable as a decolorization treatment technique for treated water subjected to anaerobic biological treatment.

Examples of the precipitation treatment by adding a flocculant include the methods described in Patent Documents 1 to 3 below.
Patent Document 1 states that “the wastewater to be discarded is once subjected to solid-liquid separation treatment such as neutralization treatment and aeration treatment, and then the inorganic salt-based flocculant and a small amount of cationic polymer flocculant in the separated wastewater. Is added to the mixture and stirred, and the colored wastewater is decolorized by aggregating and precipitating the colored substances contained in the wastewater ”(claim). 1). The problem to be solved by the invention described in Patent Document 1 is to perform a decoloring treatment without using a bleaching agent containing chlorine such as sodium hypochlorite, and as an inorganic salt-based flocculant, polychlorinated Aluminum, aluminum oxide, aluminum sulfate, aluminum chloride, etc. are used, and as a cationic polymer flocculant, a polycondensation product of a secondary amine such as dimethylamine, methylethylamine, diethylamine and epichlorohydrin or a modification thereof. (See paragraph 0012 of the same document). In the invention described in the cited document 1, both the inorganic salt-based flocculant and the cationic polymer flocculant are added to the colored wastewater in the same first decolorization reaction tank (the same paragraphs 0016 to 0019, (See FIG. 2).

  Patent Document 2 states that “a cationic polycondensate is added to and mixed with food processing colored waste liquid, and then excess sludge is mixed, and then cationic and / or amphoteric polymerization polymers are added and mixed, and then dehydrated by a dehydrator. A method for treating colored waste liquid for food processing ”is disclosed (refer to claim 1 of the same document). The problem to be solved by the invention described in the cited document 2 is that in the decolorization treatment using a combination of an inorganic flocculant such as ferric chloride or polyaluminum chloride and slaked lime, sludge after solid-liquid separation is When a large amount of gas is generated and corrosive gas is generated, a corrosive gas such as hydrogen chloride is generated and a large amount of fuel is required. Decolorization treatment is performed by combining a polycondensate and a cationic polymer. Cationic polycondensates used include condensates of dicyandiamide, cyanamide, guanidine and the like with formaldehyde, condensates of dimethylaniline, benzylamine and formaldehyde, and polyamines such as diethylenetriamine and hexamethylenediamine with formaldehyde. Condensates are mentioned (see paragraph 00003 of the same document). In addition, examples of the cationic and / or amphoteric polymer used include acrylic, diallylamine, amidine, and vinylamine. As diallylamine, diallyldimethylammonium chloride or diallyl monomethyl and acrylamide are used. Polymers are mentioned. In Examples 1 to 5 of Cited Document 2, it is described that C1 to C-3 or A1 to A2 shown in the list of polymer flocculants (Table 1) was used in addition to the dicyandiamide / formaldehyde polycondensate. (See paragraph 0023 of the same book), cited document 2 is missing Table 1, etc., and it is unclear which polymer flocculant was used.

In paragraphs 0017 to 0018 of Cited Document 2, “First, cationic polycondensate is added to the colored waste liquid to neutralize the charge of the soluble coloring component to form fine water-insolubilized particles. In this state, precipitation does not occur easily and separation is difficult, so part of the cationic and / or amphoteric polymer used in the second stage is added to facilitate the growth and aggregation of the finely insolubilized particles. Thereafter, it is mixed with food processing wastewater sludge, and a cationic and / or amphoteric polymerization polymer is added and mixed, at which time particles in the sludge form aggregated flocs by cross-linking adsorption, and further by cationic polycondensate. Fine particles composed of colored components of the colored waste liquid formed are also taken up by the sludge flocs and agglomerate together to form a large dewaterable floc. In order to form a suitable floc, it is necessary to neutralize the charge of the hydrophilic colloid material in the sludge and to coagulate the coexisting coarse particles due to the cross-linking and adsorption action. Part of the polymer flocculant added before may or may not be added depending on the insolubilized state of the colored waste water, and can be determined depending on the subsequent processing state. However, the molecular weight of the cationic and / or amphoteric polymerization polymer in the second stage is an important factor, so that it can be used in the treatment method of the present invention. From 20 to 20 million, more preferably from 2 to 15 million.If the molecular weight becomes 20 million or more and becomes too high, the floc becomes too large and the dehydration efficiency is considered from the above-mentioned aggregation mechanism. It is described as reduced to. ".
That is, in Patent Document 2, the cationic polycondensate is added to the colored waste liquid in the first stage, and a part of the cationic and / or amphoteric polymer used in the second stage is added. Sludge is mixed, and then cationic and / or amphoteric polymerized polymer is added and mixed in the second stage.

Patent Document 3 states that “a biological treatment step of biologically treating colored wastewater to obtain primary treated water, an inorganic flocculant of 1000 to 5000 mg / l with respect to the primary treated water, 1 to 40 parts by weight of a coagulant with respect to 100 parts by weight of the inorganic flocculant and 0 to 1 part by weight of an organic polymer flocculant with respect to 100 parts by weight of the inorganic flocculant are added to the primary treated water. And a coagulation-sedimentation treatment step of separating the produced coagulated sludge and the secondary treated water, ”a wastewater decolorization method is disclosed (see claim 1 of the same document).
That is, in the invention described in Patent Document 3, inorganic aggregation such as ferrous chloride, ferric chloride, ferrous sulfate, ferric sulfate, sulfate bands, polyiron sulfate, aluminum sulfate, and polyaluminum chloride. Teaches the use of agents (see paragraph 0017). In addition, as an organic polymer flocculant or coagulant, a condensation polymer of secondary amine (dimethylamine, methylethylamine, diethylamine, methylpropylamine, methylbutylamine, dibutylamine, etc.) and epichlorohydrin or a modified product thereof. Polydiallyldimethylammonium chloride, dicyandiamide cationic coagulant, polyacrylamide cationic coagulant and the like (see paragraph 0019 of the same document).

JP-A-6-226265 JP 2001-162285 A JP 2003-181491 A

  In view of the present state of the art, the problem to be solved by the present invention includes a coloring component that is known to be a hardly decomposable organic substance but whose properties are unclear, for example, a distillation residual liquid waste water from a whiskey manufacturing factory or the like An object of the present invention is to provide a wastewater decolorization method that has a small amount of coagulated sludge, a low running cost, and a high decolorization effect.

As a result of intensive studies and repeated experiments to solve the above problems, the present inventors have found that the above problems can be solved by a combination of a specific cationic coagulant and a cationic coagulant, and to complete the present invention. It came.
That is, the present invention is as follows.

[1] The following steps:
In the first flocculation tank, polydiallyldimethylammonium chloride is added as a cationic coagulant to the zero-order treated water obtained by anaerobic biological treatment of the colorant-containing wastewater, and the color component micro flocs are added. Condensation and primary treatment process to form
In the second flocculation tank, dimethylaminoethyl methacrylate methyl chloride is added as a cationic flocculant to the primary treated water that has undergone the primary treatment step to form a coarse floc in which the fine flocs are aggregated. A solid-liquid separation step of separating the secondary treated water that has undergone the treatment step and the secondary treatment step into agglomerated sludge and tertiary treated water in a solid-liquid separation tank;
including,
A method for decolorizing wastewater subjected to anaerobic biological treatment.

  [2] The amount of polydiallyldimethylammonium chloride added to the zero-order treated water: The mass ratio of the amount of methyl dimethylaminoethyl methacrylate methyl chloride added to the primary treated water is 2: 1. Method.

  [3] The amount of polydiallyldimethylammonium chloride added to the 0th treated water is 10 to 30 mg / L, and the amount of dimethylaminoethyl methacrylate methyl chloride added to the first treated water is 3 to 16 mg / L. The method according to [1] or [2] above.

  [4] The method according to any one of [1] to [3], wherein the wastewater containing the coloring component is a distillation residue wastewater from a whiskey manufacturing factory.

  In the method for decolorizing wastewater of the present invention, the zero-order treated water that has been previously subjected to anaerobic biological treatment is precipitated by adding a flocculant, that is, COD (Chemical Oxygen Demand) or BOD that can inhibit the effect of reducing chromaticity. Add polydiallyldimethylammonium chloride as a cationic coagulant in two separate flocculation tanks to zero-order treated water from which organic substances such as (Biochemical Oxygen Demand) have been sufficiently removed, and remove minute flocs of coloring components. A coagulation / primary treatment step to form, and a flocculation / secondary treatment step of adding methyl dimethylaminoethyl methacrylate methyl chloride as a cationic flocculant to the primary treated water to form a coarse floc aggregated with the micro flocs. By performing in order, the inorganic coagulant is not used, the production amount of coagulated sludge can be sufficiently reduced, the running cost is low, and the high level It is possible to exert a degree reduction effect.

It is a block diagram explaining the outline | summary of the wastewater treatment of the decoloring method of this invention. Conceptual diagram of condensation and aggregation.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a block diagram illustrating an outline of waste water treatment of the decolorization method of the present invention. The distillation residual liquid (waste water) containing the coloring component is pH-adjusted in the pH adjustment tank 1 and sent to the anaerobic treatment apparatus 2, where COD and BOD are removed. Thereafter, nitrification treatment for removing ammonia and nitrogen components is performed in the nitrification tank 3 to obtain zero-order treated water. In the first coagulation tank 4, polydiallyldimethylammonium chloride is added as a cationic coagulant to the zero-order treated water to form fine flocs of coloring components, thereby obtaining primary treated water. To the primary treated water, dimethylaminoethyl methacrylate methyl chloride is added as a cationic flocculant in the second flocculating tank 5 to form a coarse floc in which the fine flocs are aggregated to obtain secondary treated water. After that, the secondary treated water is solid-liquid separated into the coagulated sludge and the tertiary treated water in the solid-liquid separation tank 6, and the tertiary treated water is aerobically biologically treated in the aeration tank 8 together with the waste water in the factory. Then, surplus sludge is settled and separated in the settling tank 9, and the treated water is discharged into the river. Aggregated sludge and surplus sludge are applied to the sludge dewatering machine 10, and then the sludge is dried by the dryer 11 to obtain dried sludge. Sold the dried sludge as fungal fertilizer.
In the present invention, the cationic coagulant is added in the first coagulation tank 4, and the cationic coagulant is added in the second coagulation tank 5. That is, the cationic coagulant and the cationic flocculant are added in this order and in separate tanks.

In the present invention, the coagulant used is poly-dadomac (registered trademark) which is a cationic coagulant, that is, polydiallyldimethylammonium chloride (hereinafter also simply referred to as “dadomac”). Dadmac has an average molecular weight of about 200,000 and is a polymer. The trade name of Dadomac is NH-FLO 45B, the manufacturer is SMF Flower, a French flocculant marker, and the distributor is Nippon Health Industry Co., Ltd.
Dadomac has an action (condensation action) to make colloidal particles in the zero-order treated water into fine flocs.
In general, inorganic coagulants include sulfate bands, aluminum chloride, polyaluminum chloride (PAC), ferric chloride, polyferric sulfate and the like. PAC is effective in improving clarity and reducing the supernatant SS, and polyferric sulfate is effective in reducing phosphorus and hydrogen sulfide, but the amount added is increased to several hundred ppm. Therefore, an inorganic coagulant is not required in the present invention. However, the present invention does not exclude the addition of an inorganic coagulant as long as the effects of the present invention are not adversely affected.

  As the organic coagulant, in addition to Dadomac used in the present invention, melanic acid colloid effective for COD reduction and dicyandiamide effective for decolorization are known. It is known that the effect of organic coagulants increases when used in combination with inorganic coagulants. In general, the amount of organic coagulant added is several tens of ppm, and the amount of coagulated sludge generated can be reduced compared to inorganic coagulants. In the present invention, no organic coagulant other than Dadomac is required. However, the present invention does not exclude the addition of organic coagulants other than Dadomac as long as the effects of the present invention are not adversely affected.

  Other organic coagulants that can be used in the present invention have an action (coagulation action) to make colloidal particles in the zero-order treated water into fine flocs, such as secondary amines (dimethylamine, methylethylamine, diethylamine). , Methylpropylamine, methylbutylamine, dibutylamine and the like) and epichlorohydrin condensation products or modified products thereof, dicyandiamide cationic coagulants, polyacrylamide cationic coagulants and the like. Moreover, the average molecular weight of these coagulants is usually about several thousand to several tens of thousands.

  In the present invention, the amount of polydiallyldimethylammonium chloride added to the zero-order treated water is preferably 10 to 30 mg / L.

The cationic flocculant used in the present invention is dimethylaminoethyl methacrylate methyl chloride. The dimethylaminoethyl methacrylate methyl chloride may be, for example, dimethylaminoethyl methacrylate methyl chloride quaternary chloride homopolymer as a main component, and manufactured and sold by Nippon Health Industry Co., Ltd. and trade name Health Flock C904.
Dimethylaminoethyl methacrylate methyl chloride has an action (aggregation action) in which fine flocs formed by the coagulant are aggregated through adsorption / crosslinking to form coarse flocs.

  As the polymer flocculant, carboxylic acid-based anionic polymer flocculants that are widely applicable to coagulation and precipitation treatment, sulfonic acid-based anionic polymer flocculants that are effective for wastewater with large pH fluctuation, and large effects on acidic wastewater Nonionic polymer flocculant system, combined with inorganic coagulant, amphoteric polymer flocculant said to have great effect on difficult-to-dehydrate sludge, methacrylic acid ester said to have great effect on belt press dehydrator A cationic cationic polymer flocculant and an acrylic ester cationic polymer flocculant which is considered to be highly effective for centrifugal dehydrators are known. The dimethylaminoethyl methacrylate methyl chloride used in the present invention belongs to the methacrylic acid ester cationic polymer flocculant described above.

  In the present invention, the use of a polymer flocculant other than dimethylaminoethyl methacrylate methyl chloride that aggregates the fine flocs formed by the coagulant through adsorption / crosslinking to form coarse flocs is not excluded. Absent. The average molecular weight of the polymer flocculant other than dimethylaminoethyl methacrylate methyl chloride is usually several hundred thousand or more.

  In the present invention, the amount of methyl dimethylaminoethyl methacrylate added to the primary treated water is preferably 3 to 16 mg / L.

  In the present invention, the mass ratio of the amount of polydiallyldimethylammonium chloride added to the zero-order treated water: the amount of methyl dimethylaminoethyl methacrylate methyl chloride added to the primary treated water is preferably about 2: 1. .

  As described above, in the present invention, polydiallyldimethylammonium chloride is added in the first flocculation tank 4, and dimethylaminoethyl methacrylate methyl chloride is added in the second flocculation tank 5. That is, polydiallyldimethylammonium chloride and dimethylaminoethyl methacrylate methyl chloride are added in this order and in separate tanks. As a result, as shown in FIG. 2, the colloidal particles in the zero-order treated water are made into fine flocs (coagulation action) and the fine flocs formed by the coagulant are aggregated through adsorption / crosslinking to be coarse. The action of forming flocs (aggregation action) is effectively carried out, and the waste water color reduction effect by aggregation of the colored components and subsequent separation can be enhanced.

In the present invention, the waste water containing the coloring component is preferably a distillation residual liquid waste water from a whiskey manufacturing factory. Although it is known that the coloring component in the distillation residual liquid (waste water) in the whiskey factory is a hardly decomposable organic substance, its property is not clear. In addition, the waste water contains a large amount of phosphorus at 2 to 300 mg / L.
From the following examples, it is clear that the decolorization method of the present invention is applicable to decolorization of wastewater after anaerobic biological treatment derived from wastewater containing coloring components.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to an Example.
[Example 1] Inorganic (aluminum) coagulant and organic coagulant selection test First, aluminum coagulant formulation (aluminum chloride and anionic polymer flocculant) and organic coagulant formulation (Dadmac and cationic polymer coagulant) Which agent C904) is suitable for decolorization was examined.
Jar test was conducted with anaerobic treated water after anaerobic treatment of wastewater discharged from whiskey manufacturing plant. As a result, in the prescription of the aluminum-based flocculant, the degree of decolorization was good and a clear supernatant liquid was obtained. However, since the addition amount of 9% aluminum chloride was as large as 1,000 mL / m ³ , The amount generated increased. On the contrary, in the organic coagulant formulation, the transparency of the supernatant liquid was inferior to that of the aluminum coagulant formulation, but the degree of decolorization was in an acceptable range, compared to the aluminum coagulant formulation, Since the amount of chemical injection was as small as Dadomac: 10 mg / L and cationic polymer flocculant C904: 3 mg / L, the generation amount of coagulated sludge was reduced.

  Table 1 below shows a comparison result when Dadomac is selected as the coagulant and when an inorganic coagulant (PAC: polyaluminum chloride) is selected. Here, the chemical addition amount ratio and the sludge generation amount ratio are ratios when Dadmac is set to 1. Moreover, the chromaticity of waste water both decreased. From the results in Table 1, it can be seen that selecting Dadomac can reduce both the amount of added chemical and the amount of sludge generated.

  As a result of comparing the running costs, it was found that the running cost of the organic coagulant formulation was about 40% of the running cost of the aluminum coagulant formulation.

[Example 2] Selection of flocculant to be combined with dadomac Comparison results when dadomac is selected as the organic coagulant and when an inorganic coagulant is further added and the flocculant is an anionic polymer flocculant are shown below. It shows in Table 2. Here, the chemical addition amount ratio and the sludge generation amount ratio are ratios when Dadmac is set to 1. In addition, the chromaticity of the wastewater both decreased. From the results in Table 2, it can be seen that selecting Dadomac can reduce both the chemical addition amount and the sludge generation amount.

[Example 3] Examination of mass ratio of addition amount of dadomac and addition amount of cationic polymer flocculant C904 Addition ratio of dadomac and cationic polymer flocculant C904 to anaerobic treated water with chromaticity of 1,545 (unit) The change in the chromaticity of the treated water was examined by changing.
The results are shown in Table 3 below.

  From Table 3, it was found that when the combination of Dadomac and cationic polymer flocculant C904 is used, the chromaticity (unit) is well reduced at an addition ratio of about 2: 1.

  The decolorization method of the present invention does not use an inorganic flocculant, can sufficiently reduce the amount of agglomerated sludge produced, has a low running cost, and can exhibit a high level of chromaticity reduction effect. It can be suitably used for distillation residue wastewater containing coloring components from a distillation factory.

DESCRIPTION OF SYMBOLS 1 pH adjustment tank 2 Anaerobic treatment apparatus 3 Nitrification tank 4 First coagulation tank 5 Second coagulation tank 6 Solid-liquid separation tank 7 Raw water tank 8 Aeration tank 9 Precipitation tank 10 Sludge dehydrator 11 Dryer

Claims (4)

The following steps:
In the first flocculation tank, polydiallyldimethylammonium chloride is added as a cationic coagulant to the zero-order treated water obtained by subjecting the wastewater containing the colored component to anaerobic biological treatment. Condensation and primary treatment process to form flock,
In the second flocculation tank, dimethylaminoethyl methacrylate methyl chloride is added as a cationic flocculant to the primary treated water that has undergone the primary treatment step to form a coarse floc in which the fine flocs are aggregated. A solid-liquid separation step of separating the secondary treated water that has undergone the treatment step and the secondary treatment step into agglomerated sludge and tertiary treated water in a solid-liquid separation tank;
including,
A method for decolorizing wastewater subjected to anaerobic biological treatment.   The method according to claim 1, wherein a mass ratio of the addition amount of polydiallyldimethylammonium chloride to the zero-order treated water: the addition amount of dimethylaminoethyl methacrylate methyl chloride to the primary treated water is 2: 1.   The amount of polydiallyldimethylammonium chloride added to the zero-order treated water is 10 to 30 mg / L, and the amount of dimethylaminoethyl methacrylate methyl chloride added to the primary treated water is 3 to 16 mg / L. Item 3. The method according to Item 1 or 2.   The method according to any one of claims 1 to 3, wherein the wastewater containing the coloring component is a distillation residue wastewater from a whiskey manufacturing factory.

Images