JPS631114B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for decolorizing and purifying colored wastewater in a dyeing process, such as colored water discarded after completion of dyeing in a dyeing factory or the like, and colored water discarded after the washing process of dyed dyed products. In dyeing factories, various dyes and dyeing aids such as direct dyes, acid dyes, disperse dyes, and reactive dyes are used.Dyeing wastewater is discarded after dyeing the dyed object, and washing water is discarded after washing the dyed object with water. If wastewater and the like are discharged into rivers and the like without treatment, the rivers will be significantly polluted, so there has been a desire for measures to make the dyeing process wastewater pollution-free. Although several proposals for such countermeasures have been known in the past, none of them are yet sufficient. For example, a method of treatment with activated sludge,
There are methods such as treatment with coagulation-sedimentation agents and adsorption treatment with activated carbon, but with these methods,
The decolorization and purification efficiency is low, and increases in COD (chemical oxygen demand) and BOD (biological oxygen demand) cannot be sufficiently prevented. Furthermore, implementing these methods requires a large amount of equipment, operation, etc., and is difficult to implement industrially. The present inventors conducted various experimental studies to solve the above problems, and found that when tablets containing trichlorinated isocyanuric acid as a main component were immersed in flowing dyeing process wastewater, They discovered that not only decolorization of wastewater occurs, but also an increase in COD and BOD can be prevented, and the present invention was completed. An object of the present invention is to provide a method for efficiently decolorizing and purifying colored wastewater from a dyeing process, and a further object is to provide a method for decolorizing and purifying dyeing process wastewater easily and at low cost. It's about doing. The dyeing process wastewater of the present invention is characterized in that it is brought into contact with tablets containing chlorinated isocyanuric acid. Dyeing process wastewater that is the object of the present invention is, for example, colored waste water that is discarded after dyeing objects with a dyeing solution using ordinary dyes such as direct dyes, acid dyes, disperse dyes, and reactive dyes in dyeing factories. waste water,
This is colored wastewater or mixed wastewater used for washing dyed products dyed with the above-mentioned dyeing solution, and usually contains less than 0.2% dye and has a high degree of coloring. Even if this colored wastewater is diluted 10 to 100 times with water, it is still highly colored and cannot be discharged into rivers. Examples of the chlorinated isocyanuric acid used in the present invention include sodium salts or potassium salts of trichlorinated isocyanuric acid, dichlorinated isocyanuric acid, etc. The tablets included are prepared by blending the chlorinated isocyanuric acid with auxiliary agents, fillers, etc. Preferred tablets are obtained by blending trichlorinated isocyanuric acid with boric acid within a few percent and compressing the mixture. It can also be obtained by blending trichlorinated isocyanuric acid as the main component with sodium salt or potassium salt of dichlorinated isocyanuric acid and boric acid within a few percent, and then pressing into tablets. . Trichlorinated isocyanuric acid has a low dissolution rate in water, and sodium and potassium salts of dichlorinated isocyanuric acid have a high dissolution rate in water, so when the tablet is brought into contact with the colored wastewater, the flow rate of the wastewater is low. Alternatively, when the specific surface area of the tablet is sufficiently large, it is preferable to increase the proportion of trichlorinated isocyanuric acid in the tablet. Usually, the tablets used are preferably cylindrical or disc-shaped with a diameter of about 1 to several cm in order to facilitate tableting. When the particle size becomes small, for example, when a powdered product is brought into contact with the flowing dyeing process wastewater, it tends to settle in the lower part of the flowing water, making it impossible to efficiently purify the wastewater. Purification of the dyeing process wastewater according to the present invention is achieved by bringing the dyeing process wastewater into contact with the tablet containing the chlorinated isocyanuric acid. Upon contact, chlorinated isocyanuric acid is eluted from the tablet into the wastewater, decomposing the dissolved dye in the wastewater, decolorizing it, and avoiding an increase in COD and BOD in the wastewater. Preferred contact is achieved by placing the tablet in a water-permeable container, such as a screen, basket, etc., and immersing it in running water. Efficient decolorization and purification of wastewater can be easily achieved by appropriately selecting the flow rate of the wastewater and the contact surface area of the tablet. Thus, according to the present invention, dyeing process wastewater can be purified very easily and efficiently. The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the technical scope of the present invention is not limited thereto. Example 1 The amount of wastewater from the dyeing process in a factory equipped with 40 dyeing machines that dyes textile products is approximately 100 m ³ of wastewater per day, which is approximately 100 m 3 of wastewater per day after being used for cleaning dyed products. Washing wastewater is approximately 200m ³ per day.
After the two are mixed, approximately 300 m ³ /day of colored wastewater is discharged from the factory. This wastewater contained about 5% of direct dyes, disperse dyes, reactive dyes, surfactants, inorganic salts, etc., and was reddish brown in color. Disc-shaped tablets (diameter 35 mm, height 19 mm, weight
30g) with length, width, and height of 40cm x 50cm x 30
5 kg was placed in a polyethylene strainer of 1.5 cm in size and immersed in the waste water stream. The flow rate of wastewater is
Although the waste water was 30 cm ³ /hour, the waste water after contacting the tablets was decolored to a slightly red color to the naked eye. Furthermore, the absorbance of wavelength 540mμ light, suspended solids, COD and
When the BOD was measured, the results shown in Table 1 were obtained. Comparative Example 1 15 g of polyaluminum chloride, 8 g of sodium carbonate, and 2 g of polyacrylamide were added as a coagulation-sedimentation agent to 1 cm ³ of the same wastewater as described in Example 1, and the wastewater was treated using a coagulation-sedimentation wastewater treatment facility.
The wastewater still has a strong reddish-brown color, and the absorbance, solid content,
When COD and BOD were measured in the same manner as in Example 1, the results listed in Table 1 were obtained. Example 2 Instead of the tablets in Example 1, tablets (diameter
The purification method of the present invention was carried out in the same manner as in Example 1, except that a 35 mm, height 19 mm, weight 30 g) was used and the wastewater flow rate was 30 m ³ /hour, and the results shown in Table 1 were obtained. I got it. Table 1 also shows the results of measurements on untreated wastewater, and it is recognized that the method of the present invention is extremely effective.

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[Table] Represents quantity of quality.

Claims (1)

[Claims] 1. A method for purifying dyeing process wastewater, which comprises bringing the dyeing process wastewater into contact with a tablet containing chlorinated isocyanuric acid.