JP2003334588A - Treatment method for colored wastewater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop a treatment method for discoloring colored wastewater by adding bacteria which have the decomposition capacity of a hardly decomposable coloring compound, to highly concentrated colored wastewater. <P>SOLUTION: In the treatment method for colored wastewater, one or more kinds of bacteria selected from Citrobacter amalonaticus, Morganella morganii, and Enterococcus casseliflavas are added to colored wastewater to discolor colored wastewater under conditions of pH 7.0-9.5, a temperature of 20-45°C and a redox potential (Ag/AgCl electrode standard) of -30--550 mV. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating colored wastewater containing a coloring compound which is hardly decomposed by bacteria. More specifically, the bleaching method of the present invention is widely used in all technical fields including the bleaching process of colored wastewater generated in the dye manufacturing industry, the fiber dyeing industry, the paper / pulp dyeing industry and the like.

[0002]

2. Description of the Related Art Conventionally, since coloring substances in waste water are generally hardly biodegradable, it is impossible to remove them by only biological treatment such as activated sludge. Coagulation-precipitation method using iron, floatation separation method, adsorption method using activated carbon, and oxidative decomposition treatment method using sodium hypochlorite, ozone, etc. have been used. However, coagulation-sedimentation and flotation separation methods are difficult to treat waste sludge, activated carbon has problems in complication of regeneration process and economical efficiency, and sodium hypochlorite produces total organic halogen compounds (TOX). Safety and ozonation question high running costs.

Therefore, as a method for solving these problems, a method of decolorizing a dye using bacteria has been studied.
As an example of such a decolorization method, decomposition of a benzene ring-containing dye by Nocardia coralina species (JP-A-48)
-56881), decomposition of basic dyes by the genus Pseudomonas (JP-A-48-82662), and monoazo, diazo, anthraquinone, triphenylmethane, methine, and monoazo polymer dyes by the genus Alcaligenes. Decolorization (Japanese Patent Application Laid-Open No. 63-216472), color erasing or reduction of the azo dye coloring liquid by each bacterium belonging to the genus Bacillus, Xanthomonas, and Achromobacter (Japanese Patent Laid-Open No. 8-261). As described above, when treating a dye coloring liquid using bacteria, it is found that there is a clear peculiarity in the relation between bacteria and the dye to be treated.

[0004]

The problem to be solved by the present invention is to decolorize a colored wastewater by adding a bacterium having a decomposability of a hardly-decomposable coloring compound to a colored wastewater, particularly a colored wastewater containing at least an azo dye. It is to provide the processing method to do. Direct dyes for highly concentrated colored wastewater discharged from the dye manufacturing industry, textile dyeing industry, paper / pulp dyeing industry, etc.
It includes acid dyes, reactive dyes, cationic dyes, sulfur dyes, disperse dyes and the like. Their dye structures are monoazo, disazo, trisazo, tetraazo, gold-containing azo,
These are formazan-based, phthalocyanine-based, and anthraquinone-based persistent compounds, and the colored wastewater discharged is a mixed solution of these compounds. Among the various dyes currently used, the azo dye is about 60-7.
It has a utilization rate of 0% and is used in a large amount in a wide range of technical fields such as dyeing of fabrics, dyeing of foods, dyeing of papers, etc. Naturally, a large amount of azo dye is also contained in the waste liquid of these dyes.

Further, the coloring wastewater contains dye manufacturing industry,
It also includes raw materials discharged from the dye industry, intermediate production by-products, dispersants, solubilizers, surfactants, leveling agents, fixing agents, sizing agents, soaping agents, etc., which complicates problem solving. . That is, there is a demand for a low-cost treatment method using a highly resistant bacterium that decomposes and decolorizes various dyes and proliferates even when the above compound is present in wastewater.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned conventional drawbacks, the present inventor has found that certain bacteria are difficult to decompose in coloring wastewater, particularly coloring wastewater containing at least an azo dye. Focusing on decomposition and decolorization of compounds, it was found that the above-mentioned object can be achieved by proliferating these compounds predominantly in a coloring wastewater system, and the present invention has been completed based on this finding.

That is, the present invention relates to the following (1) to (6). (1) One or more kinds of bacteria selected from bacteria belonging to the genus Citrobacter, the genus Morganella and the genus Enterococcus are added to the colored wastewater, and the pH is 7.0 to 9.5 and the temperature is 20 to 45.
C, redox potential (Ag / AgCl electrode reference) -30 to
A method for treating colored wastewater, which comprises decolorizing at −550 mV. (2) Bacteria are Citrobacter amaronaticus,
The method for treating colored wastewater according to (1), which is one or more selected from Morganella morgani and Enterococcus casei flavus. (3) The bacterium is Citrobacter amalonaticus
MH-1 (FERM P-18145) strain, Morganella morgani MH-2 (FERM P-18146) strain and Enterococcus casei flavus MH-3 (F
The method for treating colored wastewater according to (1), which is one or more selected from ERM P-18147) strains.

(4) The treatment method according to any one of (1) to (3), wherein the colored wastewater is a colored wastewater containing at least an azo dye. (5) The colored wastewater is a highly colored wastewater of ΣOD6 or more,
The processing method according to any one of (1) to (4). (6) Citrobacter amaronaticus MH-1 (F
ERM P-18145) strain, Morganella morgani MH-2
(FERM P-18146) strain or Enterococcus ca. flavus (Enterococcus ca)
sseliflavas) MH-3 (FERM P-1
8147) strains.

In the wastewater containing at least an azo dye, which is applied to the present invention, various azo dyes are included as the azo dye, and the basic structure is a monoazo dye, a disazo dye,
Azo dyes having various basic structures such as trisazo dyes, tetraazo dyes, and metal-containing azo dyes are included.

In the bacterium used in the present invention, examples of the bacterium belonging to the genus Citrobacter include, for example, Citrobacter amaron
aticus) species, IFO 13547, ATCC
25405, ATCC25406, ATCC2540
7, MH-1 strain (Institute of Industrial Science and Technology, Institute of Biotechnology, Industrial Technology F
ERM P-18145) and the like.

(A) Citrobacter amaronaticus
s) Isolation, Characterization, and Identification of MH-1 Strain In the above, Citrobacter amaronatecus (Cit
roba amalonaticus) MH-
1 share (Institute of Industrial Technology, Biotechnology Institute of Industrial Technology FERM
P-18145) is a novel strain, and is isolated from, for example, activated sludge (dye manufacturing factory), and the mycological properties are as follows. Dilute the sludge sample and use CI Reactiv
E Red 120 was smeared on a standard agar medium (manufactured by Nissui Pharmaceutical Co., Ltd.) containing 250 ppm, and the colonies decolorized from the agar medium at the highest dilution rate that had been grown were cultivated and isolated on a standard agar medium. The culture was carried out at 28 ° C. for 48 hours. Then
Gram stain of the isolated bacteria was performed, and the Gram stainability and morphology were observed by a microscope. As the biochemical properties, a glucose oxidative fermentation test, a catalase test, an oxidase test, and a property test using Api 20E and Api 50CH (manufactured by Japan Biomerieu Vitec) were performed to identify the bacteria. As a result, the isolated bacterium was a gram-negative facultative anaerobic bacillus, Citrobacter amaronatecus (Citrob).
It has been identified as a bacterium belonging to the species Acta amalonaticus). This bacterium is designated as Citrobacter amalonatic
us) MH-1 strain, and its properties and identification results are shown in Table 1.
It was shown to.

Table 1 Test item MH-1 strain Morphology bacillus Gram stain negative Aerobic growth + Anaerobic growth + Motility + Glucose oxidative fermentation Fermentation Kataraze + Oxidase Property test by API 20E

[0013] β-galactosidase + Arginine dihydrase + Lysine decarboxylase − Ornithine decarboxylase + Sodium citrate assimilation − Hydrogen sulfide production − Urea decomposition − Tryptophan deaminase- Indole production ＋ Acetoin production − Degradation of gelatin − Oxidation test Glucose + D-mannitol + Inosit- D-sorbitol + L-rhamnose + White sugar + D-Melbiose + D-Amygdalin + L-arabinose +

[0014] Carbohydrate metabolism test using API 50CH Glycerol- Erythritol − D-arabinose + L-arabinose + Ribose + D-xylose + L-xylose- Adonitol- β-methyl D-xyloside- Galactose + Glucose + Fructose + Mannose + Sorbose + Rhamnose + Dulcitol- Inositol- Mannitol + Sorbitol +

[0015] α-methyl-D mannoside- α methyl-D glycoside + N acetylglucosamine + Amygdalin − Arbutin + Esculin + Salicin + Ceribiose + Maltose + Lactose + Meribiose + Sucrose + Trehalose + Inulin − Melettitose- Raffinose + Starch- Glycogen − Xylitol- Gentibiose + D-Turanose + D-Liquisose- D-Tagatose + D-Fucose- L-Fucose + D-arabitol- L-arabitol- Gluconate + 2-ketogluconate + 5-ketogluconate +

In the bacterium used in the present invention, the bacteria belonging to the genus Morganella include, for example, Morganella morganii species, IFO3168, IFO3848 and JCM167.
2, ATCC8019, ATCC8076, ATCC9
237, ATCC9916, ATCC23548, AT
CC23585, ATCC25829, ATCC258
30, ATCC 27974, ATCC 27975, AT
CC29853, ATCC33791, ATCC352
00, ATCC49992, ATCC499993, AT
CC49994, MH-2 strain (Institute of Industrial Science and Technology, Institute of Biotechnology, Industrial Technology FERM P-18146) and the like.

(B) Morgana Morgani
nella morganii) isolation of MH-2 strain,
Properties and identification Among the above, Morganella (Morganel)
la morgani) MH-2 strain (Institute of Industrial Science and Technology, Institute of Biotechnology, Industrial Technology FERM P-18146) is a novel strain, and is isolated from activated sludge, for example, and the mycological properties are as follows. Dilute the sludge sample to obtain CIR
Standard red agar medium containing 250 ppm of Active Red 120 (manufactured by Nissui Pharmaceutical Co., Ltd.) was smeared, and the colonies decolorized from the agar medium of the highest dilution rate grown by culturing were picked up,
Isolated on standard agar. The culture was carried out at 28 ° C. for 48 hours. Then, Gram stain of the isolated bacteria was performed, and the Gram stainability and morphology were observed by a microscope. As the biochemical properties, a glucose oxidative fermentation test, a catalase test, an oxidase test, and a property test using Api 20E and Api 50CH (manufactured by Japan Biomerieu Vitec) were performed to identify the bacteria. As a result, the isolated bacterium was a gram-negative facultative anaerobic bacillus, Morganella (Morgan).
It was identified as a bacterium belonging to the species ella morganii). This fungus is called Morganella Morgan
ella morganii) MH-2 strain, and its properties and identification results are shown in Table 2.

Table 2 Test item MH-2 strain Morphology bacillus Gram stain negative Aerobic growth + Anaerobic growth + Motility + Glucose oxidative fermentation Fermentation Kataraze + Oxidase

Property test by API 20E β-galactosidase- Arginine dihydrase- Lysine decarboxylase − Ornithine decarboxylase + Sodium citrate assimilation − Hydrogen sulfide production − Urea decomposition + Tryptophan deaminase + Indole production ＋ Acetoin production − Degradation of gelatin − Oxidation test Glucose + D-mannitol- Inosit- D-sorbitol- L-Rhamnose- White sugar D-Melbiose- D-Amygdalin- L-arabinose-

Carbohydrate metabolism property test with API 50CH Glycerol + Erythritol − D-arabinose- L-arabinose- Ribose + D-xylose- L-xylose- Adonitol- β-methyl D-xyloside- Galactose + Glucose + Fructose + Mannose + Sorbose − Rhamnose- Dulcitol- Inositol- Mannitol + Sorbitol

[0021] α-methyl-D mannoside- α-methyl-D glycoside- N acetylglucosamine + Amygdalin − Arbutin- Esculin − Salicin − Ceribiose − Maltose- Lactose- Meribiose- Sucrose- Trehalose + Inulin − Melettitose- Raffinose- Starch- Glycogen − Xylitol + Gentibios- D-Tranose- D-Liquisose- D-Tagatose- D-Fucose- L-Fucose- D-arabitol- L-arabitol- Gluconate + 2-ketogluconate- 5-ketogluconate-

Next, among the bacteria used in the present invention, examples of bacteria belonging to the genus Enterococcus include Enterococcus casei flavus (Enterococcus).
Casseliflavas) species as JCM565
7, JCM8716, JCM8723, IFO353
1, IFO 12225, IFO 12256, IFO 13
138, ATCC12755, ATCC12817, A
TCC12816, ATCC12819, ATCC14
432, ATCC14436, ATCC25788, A
TCC25789, ATCC49604, ATCC49
605, ATCC 51328, MH-3 strain (Institute of Biotechnology, National Institute of Biotechnology, FERM P-18147)
However, the present invention is not limited to these.

(C) Enterococcus caseliflav
as) Isolation, Characterization, and Identification of MH-3 Strains Among the above, Enterococcus casei flavus (En
terococcuscasseliflavas) M
H-3 strain (Institute of Biotechnology, Industrial Technology Research Institute FER
MP-18147) is a novel strain, and is isolated from activated sludge, for example, and the mycological properties are as follows. Dilute a sludge sample and use CI Reactive Red12
0 was added to tryptosoy agar medium (manufactured by Eiken Kagaku Co., Ltd.) containing 250 ppm, and the culture was decolorized to isolate the bacterium. Then, after morphological observation and a physiological property test are performed on the isolated bacterium to determine the genus, the automatic bacterium inspection apparatus ATB Express
The identification test was carried out by using Sion (bioMerieuxsa; Japan BioMerieux Vitec Co., Ltd.). However, for the test, Streptococcus identification kit rapid ID
32 STREP (bioMerieux sa; Japan BioMerieux Vitec Co., Ltd.) was used. In addition, quinone series analysis and GC content of intracellular DNA were also measured. As a result, the isolated bacterium was a gram-positive facultative anaerobic coccus, Enterococcus casei flavus (Ente.
was identified as a bacterium belonging to the species Rococcus casseliflavas (Bergey's Man)
ual of Determinative Bact
erology, Ninth Edition,
1994). This fungus is called Enterococcus casselifla
vas-3 strain was named MH-3. The main properties of the strain are shown in Table 3, and the properties and identification results of the kit are shown in Table 4.

[0024] Table 3 Test item MH-3 strain Morphology Gram stain positive Spore − Motility + Attitude toward oxygen Aeration anaerobic Catalase- Lactic acid produced L (+) Gas production from glucose − Growth at 10 ℃ + Growth at 45 ℃ + Growth in the presence of 6.5% NaCl + Growth at pH 9.6 + Village color tone yellowish No major quinoline type detected                                   (Detects trace amounts of MK-8 and MK-7) GC content (mol%) of intracellular DNA 42

Table 4 Test item MH-3 strain Arginine dihydrase- β-glucosidase + β-galactosidase- β-glucuronidase- α-galactosidase- Alkaline phosphatase − Acid generation Ribose + Mannitol + Sorbitol Lactose + Trehalose + Raffinose- Acetoin production ＋ Alanine-Phenylalanine- Proline allyl amidase − β-galactosidase + Pyroglutamate allyl amidase + N-acetyl-β-glucosaminide- Glucyl-tryptophan allyl amidase + Sodium hippurate hydrolysis −

Acid formation Glycogen − Pull Run − Maltose + Melettitose- Sucrose + L-arabinose + D-arabitol- Methyl-β-D-glucopyranoside + Tagatose- Cyclodextrin − Glycerol- β-mannosidase- Urease − Formation of yellow pigment +

In carrying out the present invention, one or more of the present bacterium may be added directly to the colored wastewater, or precultured cells may be added to the colored wastewater. In culturing, although not particularly limited, various carbon sources such as glucose, proteins, peptone, yeast extract, meat extract, carbon nitrogen sources such as amino acids, ammonium sulfate, sodium nitrate, magnesium sulfate, sodium chloride, potassium phosphate, etc. It is possible to use a medium to which various inorganic salts described above are added. The pH in the culture is 7.0 to 9.5 and the temperature is 20.
Incubate statically at ~ 45 ° C.

When decolorizing colored wastewater using the present invention,
The pH of the waste water is 7.0 to 9.5, the temperature is 20 to 45 ° C., and the oxidation-reduction potential (Ag / AgCl electrode standard) (hereinafter referred to as ORP) is set to −30 to −550 mV. The redox potential (Ag / AgCl electrode reference)
The condition of −30 to −550 mV indicates the range in which the facultative anaerobic bacteria used in the present invention are decomposed and decolorized. If the wastewater does not meet this set standard, it can be adjusted by aeration or deaeration. Further, the time required for the treatment using the bacterial cells is usually about 6 hours to 1 week.

In the present invention, since the present strain is facultatively anaerobic, it grows without decomposition under aerobic conditions such as shaking, stirring, and aeration air, and decomposition and decolorization proceed, so that it is economical. Is also advantageous. Furthermore, in the present invention, the strain is a raw material, an intermediate, a dispersant, a solubilizer,
Even if it contains a surfactant, leveling agent, fixing agent, sizing agent, soaping agent, etc., it grows without being hindered, and the azo dye etc. It is possible to decompose and decolorize persistent color compounds. In addition, although many aerobic bacteria are present in wastewater, aerobic bacteria are suppressed in growth under the conditions of the above-mentioned redox potential of the present invention, which is advantageous for growth of the strain of the present invention.

Further, the present invention is characterized in that the wastewater can be efficiently decolorized even if the wastewater is highly concentrated. The high-concentration colored wastewater is usually treated as indicating a colored wastewater having a ΣOD of 6 or more, while the upper limit thereof is not particularly limited, but a colored wastewater having a ΣOD of about 700 or less is equivalent. The method for evaluating the decomposition / decolorization of a coloring compound by bacteria in the present invention was performed according to the ΣOD method (reference, pollution and countermeasures vol27 No8 741-745,
1991). Absorbance (Abs.) Was measured by Hitachi spectrophotometer U-3200. Coloring degree (ΣOD) = sum of specific wavelength OD value (absorbance) of wastewater = (400 nm) + (450 nm) + (500 nm) + (550 nm) + (600 nm) + (650 nm) Decolorization rate = (1-treatment Post-treatment wastewater ΣOD / Pre-treatment wastewater Σ
OD) × 100 For example, ΣOD60 is a dilution method (reference PPM vo
L. 21 No. 2, 8-12, 1990) corresponds to 33400 highly colored wastewater.

[0031]

EXAMPLES The present invention will be described in more detail with reference to test examples and examples, but the present invention is not limited to these examples. Test Example 1 Decolorizing ability of azo dye of strain Strain Citrobacter amaronaticus MH used in the present invention
-1 strain, Morganella morgani MH-2 strain and Enterococcus casei flavus MH-3 strain were measured for the presence or absence of the azo dye decolorizing ability. The test method was as follows: A standard dye agar (manufactured by Nissui Pharmaceutical Co., Ltd.) was used to add an azo dye (CI Reactive).
Red 120) was added so as to contain 250 ppm, the above 3 strains were smeared on each, and the state was observed after standing at 28 ° C. for 48 hours. As a result, it was confirmed that all three strains had the ability to decolorize azo dyes.

Example 1 Tryptone 1.5% in a 300 ml Erlenmeyer flask,
Enter 100 ml of a medium containing 0.5% of soypeptone, 0.5% of sodium chloride, 0.1% of lecithin, and 0.7% of polysorbate 80, and sterilize by a conventional method, and then enterococcus catseriflavus MH-3 strain (FERM
p-18147) was inoculated with one platinum loop and statically cultured at 36 ° C. for 48 hours. Add 300 ml of colored wastewater A (including azo dye factory wastewater and other dye factory wastewater) to a 500 ml Erlenmeyer flask, and add 20 m of the above culture solution.
L (2.5 × 10 ⁸ cfu / ml) was added (ΣOD149.2). Then pH 8.5, temperature 3
It was left standing at 6 ° C. and ORP-110 mV for 48 hours. The processed ΣOD was 15.2, and the decolorization rate was (1-15.2 / 1).
49.2) × 100 = 89.8%. FIG. 1 shows the absorbance (Ab) before treatment at an absorption wavelength of 400 to 650 nm.
s. ) And the full curve of the absorbance after the treatment.

Example 2 One platinum loop of the Enterococcus casseliflavus JCM8723 strain was inoculated into the same medium as in Example 1 and incubated at 30 ° C. for 4 hours.
Static culture was carried out for 8 hours. Add 300 ml of coloring wastewater B (including azo dye factory wastewater and other dye factory wastewater) to a 500 ml Erlenmeyer flask and add 2 to the above culture solution.
0 ml (2.0 × 10 ⁸ cfu / ml) was added (ΣOD155.2). Then, it was subjected to a standing treatment at pH 7.5, temperature of 30 ° C. and ORP-45 mV for 48 hours.
The processed ΣOD was 18.0, and the decolorization rate was (1-18.0 /
155.2) × 100 = 88.4%. FIG. 2 shows a full curve of the absorbance before the treatment and the absorbance after the treatment at the absorption wavelength of 400 to 650 nm.

Example 3 Medium 1 containing 0.7% meat extract, 1.0% peptone and 0.3% sodium chloride in a 300 ml Erlenmeyer flask
After adding 100 ml and sterilizing by a conventional method, one platinum loop of Morganella morgani strain MH-2 (FERM p-18146) was inoculated and statically cultured at 27 ° C. for 48 hours. 5
Into a 00 ml Erlenmeyer flask, add 300 ml of coloring wastewater C (including azo dye factory wastewater and other dye factory wastewater), and add 10 ml (1.5 × 1) of the above culture solution.
0 ⁸ cfu / ml) and the Enterococcus faecium flavus MH-3 strain (FERM obtained in Example 1).
10 ml of the culture solution of p-18147) was added (ΣOD80.9). Then pH 9.0, temperature 40
It was left to stand at OPC-440 mV for 48 hours. The ΣOD after the treatment was 1.7, and the decolorization rate was (1-1.7 / 80.
9) × 100 = 97.9%. Absorption wavelength 4
The full curve of the light absorbency before a process and the light absorbency after a process in 00-650 nm is shown.

Example 4 In a 300 ml Erlenmeyer flask, meat extract 0.5%, peptone 1.5%, sodium chloride 0.5%, phosphoric acid No. 2
100 ml of a medium containing 0.5% potassium was added and sterilized by a conventional method, and then Citrobacter amaronaticus MH-
1 strain (FERMp-18145) was planted with 1 platinum loop and 3
Static culture was carried out at 0 ° C. for 48 hours. Into a 500 ml Erlenmeyer flask, 300 ml of coloring wastewater D (including azo dye factory wastewater and other dye factory wastewater) was placed, and 10 ml (2.9 × 10 ⁸ cfu / ml) of the above culture solution and Example 1 were added. Enterococcus faecium flavus strain MH-3 obtained in (FERM p-18147)
10 ml of the culture solution was added (ΣOD116.
1). Next, pH 9.1, temperature 38 ° C, ORP-28
A static treatment was carried out at 0 mV for 48 hours. The processed ΣOD is 9.
8, decolorization rate is (1-9.8 / 116.1) × 100 = 9
It was 1.6%. Fig. 4 shows the absorption wavelength 400-650 nm
3 shows a full curve of absorbance before treatment and absorbance after treatment in FIG.

Example 5 A 500 ml Erlenmeyer flask was charged with 300 ml of coloring wastewater E (including azo dye factory wastewater and other dye factory wastewater), and the enterococcus
Katsueri flavus MH-3 strain (FERM p-1814
10 ml of the culture solution of 7), the Morganella morgani strain MH-2 obtained in Example 3 (FERMp-1814)
6 ml of the culture solution of 6) and the Citrobacter amaronaticus MH-1 strain (FERM obtained in Example 4).
10 ml of the culture solution of p-18145) was added (ΣOD255.6). Then pH 8.6, temperature 34
It was left to stand still at 48 ° C. for 48 hours at 0 ° C. The processed ΣOD was 18.3, and the decolorization rate was (1-18.3 / 25).
5.6) × 100 = 92.8%. FIG. 5 shows a full curve of the absorbance before the treatment and the absorbance after the treatment at the absorption wavelength of 400 to 650 nm.

Comparative Example 1 Sample prepared in Example 1 [Into a 500 ml Erlenmeyer flask, 300 ml of coloring wastewater A (including azo dye factory wastewater and other dye factory wastewater) was placed, and Enterococcus casseliflavus MH was added. -3 strain (FERM p-1
20 ml of culture solution containing 8147) (2.5 x 1
0 ⁸ cfu / m l) have been added (ShigumaOD14
9.2)] in a shaking incubator at pH 8.5, temperature 36 ° C., 1
It was treated at 70 rpm for 48 hours. During that time, the oxidation-reduction potential of the sample solution (Ag / AgCl electrode reference) was ORP + 100.
It was mV. The ΣOD after the treatment was 139.0, and the decolorization rate was (1-139.0 / 149.2) × 100 = 6.
It was 8%.

[0038]

According to the present invention, by adding one or more bacteria selected from Citrobacter amaronaticus, Morganella morgani and Enterococcus casei flavus to colored wastewater, especially colored wastewater containing an azo dye, Providing a low-cost and practically superior treatment method for highly concentrated colored wastewater that can decompose and decolorize mixed persistent color compounds even if the colored wastewater contains manufacturing by-products, dyeing aids, etc. it can.

[Brief description of drawings]

FIG. 1 is a diagram showing changes in absorbance and absorption wavelength before and after treatment of a colored wastewater of Example 1. (Dilution rate 50 times)

FIG. 2 is a diagram showing changes in absorbance and absorption wavelength before and after treatment of the colored wastewater of Example 2. (Dilution 50 times)

FIG. 3 is a diagram showing the absorbance and the absorption wavelength before and after the treatment of the colored wastewater of Example 3. (Dilution rate 50 times)

FIG. 4 is a diagram showing the absorbance and the absorption wavelength before and after the treatment of the colored wastewater of Example 4. (Dilution rate 50 times)

5 is a diagram showing the absorbance and the absorption wavelength before and after the treatment of the colored wastewater of Example 5. FIG. (Dilution rate 50 times)

Claims (6)

[Claims] 1. A coloring wastewater containing one or more bacteria selected from bacteria belonging to the genus Citrobacter, genus Morganella and genus Enterococcus, pH 7.0 to 9.5, and temperature 20.
~ 45 ° C, redox potential (Ag / AgCl electrode standard)-
A method for treating colored wastewater, which comprises decolorizing under a condition of 30 to -550 mV. 2. The method for treating colored wastewater according to claim 1, wherein the bacterium is at least one selected from Citrobacter amaronaticus, Morganella morgani and Enterococcus caseiflavas. 3. The bacterium is Citrobacter amaronaticus.
s) MH-1 (FERM P-18145) strain, Morganella morgani MH-2 (FERM P-1814)
6) Strain and Enterococcus casei flavus MH-
3. The method for treating colored wastewater according to claim 1, which is one or more selected from 3 (FERM P-18147) strain. 4. The treatment method according to claim 1, wherein the colored wastewater is a colored wastewater containing at least an azo dye. 5. The treatment method according to claim 1, wherein the colored wastewater is a highly colored wastewater having a ΣOD of 6 or more. 6. Citrobacter amaronaticus MH-
1 (FERM P-18145) strain, Morganella morganii M
H-2 (FERM P-18146) strain or Enterococcus flavus (Enterococcus)
casseliflavas) MH-3 (FERMP
-18147) strain.