JPH08164389A - Treatment of waste ink liquid - Google Patents

Abstract

PURPOSE: To efficiently decolor a concd. waste liquid as it is without dilution by bringing the waste ink liquid discharged from ink package producing stages, etc., related to semiconductor production into contact with a reverse osmosis membrane of a high salt removal rate to separate the liquid to a permeated liquid and the concd. liquid, adding a flocculating agent to the concd. liquid and separating the liquid to precipitate and supernatant water. CONSTITUTION: The waste liquid in an original liquid tank 1 is supplied from a piping 11 having a circulating pump 21 to a reverse osmosis membrane separator 2 to cause the reverse osmosis membrane sepn. The permeated liquid obtd. in such a manner is taken out of the piping 12 and is admitted into a treated water tank 3. The concd. liquid of the reverse osmosis membrane separator 2 is withdrawn from the piping 13 and is partly returned at need directly to the original liquid tank 1 from as piping 15. The remaining part is fed from a piping 14 to a fluocculation reaction tank. The flocculating agent 16 is added to the concd. liquid in this flocculation reaction tank 4 to effect flocculation reaction. The flocculation reaction liquid is fed from a piping 17 to a settling tank 5. The sludge subjected to settling sepn. in the setting tank 5 is withdrawn from the piping 18 outside the system and the supernatant liquid is returned from a piping 19 to the original liquid tank 1.

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 an ink waste liquid, and more particularly, to a concentrated ink waste liquid discharged from a semiconductor manufacturing-related ink package manufacturing process, etc. by using a reverse osmosis membrane separation device and a coagulating sedimentation device. The present invention relates to a method for efficiently decolorizing.

[0002]

2. Description of the Related Art Thick ink waste liquid is discharged from an ink package manufacturing process related to semiconductor manufacturing.

Conventionally, as a treatment of a diluted ink waste liquid, a coagulation sedimentation filtration and a decolorization treatment by an activated carbon adsorption method have been carried out.

However, a concentrated ink waste liquid cannot be sufficiently decolorized by such a method, and in many cases, the concentrated ink waste liquid is diluted to a low-concentration ink waste liquid and then the above decolorization treatment is performed. Is going.

Incidentally, depending on the conditions such as the concentration and the discharge amount,
Although it may be processed as industrial waste inside or outside the factory, in this case, of course, a great disposal cost is required.

[0006]

In the conventional decolorization treatment of the concentrated ink waste liquid, it is necessary to dilute the concentrated ink waste liquid, which is industrially disadvantageous in terms of the number of steps, equipment installation space, processing cost and the like. .

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and provide a method for treating an ink waste liquid which enables efficient decolorization treatment without diluting a concentrated ink waste liquid.

[0008]

According to the method for treating an ink waste liquid of the present invention, the ink waste liquid is brought into contact with a reverse osmosis membrane having a high salt removal rate to separate it into a permeate and a concentrate, and a coagulant is added to the concentrate. It is characterized by adding and separating into a precipitate and supernatant water.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a system diagram showing a method of an embodiment of a method for treating an ink waste liquid according to the present invention.

In the figure, 1 is a stock solution (ink waste solution) tank, 2 is a reverse osmosis membrane separation device equipped with a high salt removal rate reverse osmosis membrane 2A, 3
Is a treated water (permeate) tank, 4 is a coagulation reaction tank, 5 is a precipitation tank, and each symbol 11 to 19 represents a pipe. Reference numeral 21 is a pump, 22, 23 and 24 are valves, and 25 is an agitator.

In the method of this embodiment, the waste ink in the stock solution tank 1 is circulated through the reverse osmosis membrane separation device 2 through the pipe 11 equipped with the circulation pump 21 to continuously obtain the permeated liquid. That is, the waste ink in the stock solution tank 1 is supplied from the pipe 11 to the reverse osmosis membrane separation device 2 for reverse osmosis membrane separation, and the permeated liquid is taken out from the pipe 12 and received by the treated water tank 3. The concentrated liquid of the reverse osmosis membrane separation device 2 is extracted from the pipe 13. The concentrate is
If necessary, part of it is returned directly to the stock solution tank 1 through the pipe 15, and the rest is sent to the coagulation reaction tank through the pipe 14. In the agglutination reaction tank 4, an aggregating agent is added to the concentrated liquid through the pipe 16 to carry out an agglutination reaction. This aggregation reaction liquid is sent to the settling tank 5 through the pipe 17. The sludge settled and separated in the settling tank 5 is extracted from the system through the pipe 18. On the other hand, the supernatant liquid is returned to the stock solution tank 1 through the pipe 19.

According to such a treatment, the reverse osmosis membrane separation device 2 surely blocks the coloring component in the ink waste liquid, a colorless and transparent high water quality permeate is obtained as treated water, and the reverse osmosis membrane separation is performed. The colored component concentrated in the device 2 is efficiently coagulated in the coagulation reaction tank 4, and is efficiently discharged as a sludge out of the system in the settling tank 5.

As the reverse osmosis membrane having a high salt removal rate used in the method for treating an ink waste liquid according to the present invention, for example, a reverse osmosis membrane separation characteristic having a NaCl rejection rate of 99% or more is preferable. The material of the reverse osmosis membrane is not particularly limited, and a polyamide, vinyl acetate, polysulfone, or other reverse osmosis membrane can be used.

On the other hand, as the aggregating agent used in the aggregating reaction,
Magnesium chloride (MgCl ₂ ), ferrous sulfate (FeS
O ₄ ), ferric chloride (FeCl ₃ ), and other inorganic coagulants are preferable, and the amount thereof is usually about 1000 to 20000 mg / l, although it depends on the concentration of the ink waste liquid to be treated. It is important that the agglutination reaction is carried out by adjusting the pH value according to the characteristics of the aggregating agent to be added.
If necessary, a pH adjuster such as alkali is appropriately added so that the pH is in the range of 6 to 12.

The method for treating ink waste liquid according to the present invention is particularly
Includes ultrafine ink particles with a particle size of 50 μm or less used in a personal computer printer, chromaticity of 10,000 or more, CO
It is effective for treating a concentrated ink waste liquid having D _{Mn of} 5000 mg / l or more, but is not limited to this.

[0017]

By the reverse osmosis membrane having a high salt removal rate, the colored components in the ink waste liquid are reliably prevented, and the permeated liquid of high water quality is obtained. On the other hand, by subjecting the concentrated liquid to coagulation-sedimentation treatment, the colored components concentrated by the reverse osmosis membrane can be efficiently separated as sludge.

[0018]

EXAMPLES The present invention will be described more specifically with reference to Examples, Comparative Examples and Reference Examples below.

Example 1 Ink waste liquid (color: dark purple, COD _Mn : 14300 mg / l) was treated according to the method of the present invention shown in FIG.

As the reverse osmosis membrane of the reverse osmosis membrane separator, a polyamide reverse osmosis membrane (“KROA-98-HN” manufactured by Kurita Industry Co., Ltd.) with a NaCl rejection rate of 99.5% was used. Reverse osmosis membrane separation was performed at a pressure of 15 kgf / cm ² . Further, in the coagulation reaction tank, FeS is used as the coagulant.
O ₄ added 20000 mg / l, pH 10-10.5
It was processed in.

Chromaticity of the resulting treated water (permeate) (wavelength 4
Absorbance at 50 nm) and COD _Mn were measured, and the appearance was observed. The results are shown in Table 1.

Comparative Example 1 An ink waste liquid having the same water quality as that treated in Example 1 was placed in a beaker, heated and evaporated to condense the vapor. The chromaticity, COD _Mn , and appearance of the obtained coagulated water are shown in Table 1.

Comparative Examples 2 to 4 The ink waste liquid having the same water quality as that treated in Example 1 was directly subjected to coagulation-sedimentation treatment under the coagulation conditions shown in Table 1 using the coagulant shown in Table 1. Color of supernatant, CO
The appearance of D _Mn is shown in Table 1.

From Table 1, according to the method of the present invention, even the concentrated ink waste liquid is directly treated without being diluted,
It is clear that high-quality treated water with high transparency can be obtained.

[0025]

[Table 1]

Reference Example 1 An ink waste liquid having the same water quality as that treated in Example 1 was used as a reverse osmosis membrane, using a polyamide reverse osmosis membrane (“NTR-729HF” manufactured by Nitto Denko Corporation) having a NaCl blocking rate of 92%. When the reverse osmosis membrane separation treatment was performed at an operating pressure of 15 kgf / cm ² , the chromaticity of the obtained permeate was 239, and it was confirmed that sufficient decolorization was not performed.

Reference Example 2 An ink waste liquid having the same water quality as that treated in Example 1 was used as a reverse osmosis membrane using a polyamide reverse osmosis membrane (NTR-7410 manufactured by Nitto Denko Corporation) with a NaCl rejection of 10%. When the reverse osmosis membrane separation treatment was performed at an operating pressure of 10 kgf / cm ² , the obtained permeated liquid exhibited a dark purple color almost equal to that of the stock solution,
Almost no bleaching was done.

[0028]

As described in detail above, according to the method for treating an ink waste liquid of the present invention, even a thick ink waste liquid can be directly subjected to a decoloring treatment without being diluted, and high water quality with high transparency can be obtained. The treated water can be efficiently obtained.

[Brief description of drawings]

FIG. 1 is a system diagram showing an example method of an ink waste liquid treatment method according to the present invention.

[Explanation of symbols]

 1 stock solution tank 2 reverse osmosis membrane separation device 3 treated water tank 4 coagulation reaction tank 5 precipitation tank

Claims (1)

[Claims] 1. An ink waste liquid is brought into contact with a reverse osmosis membrane having a high salt removal rate to separate a permeate liquid and a concentrated liquid, and a coagulant is added to the concentrated liquid to separate a precipitate and a supernatant liquid. A characteristic method for treating ink waste liquid.