KR101837731B1 - The Disposal system of dyeing wastewater - Google Patents

Abstract

The present invention relates to a method for treating dyeing wastewater, comprising a step of neutralizing dyeing wastewater which has been preliminarily pretreated with a small amount of iron salt in an incoming alkaline dyeing wastewater, and then decomposing the organic matter by microorganism activation by aeration After the dyeing wastewater is made into a strongly alkaline state, the iron salt is added to remove the defective contaminants by a third Fenton reduction treatment method. Further, the dyeing wastewater is added to the fermentation wastewater in a strongly acidic state, After the final incompatible pollutants which are difficult to treat by the reduction treatment method are finally removed by the fourth Fenton oxidation treatment method, the pH is adjusted to 7.5 and discharged.
On the other hand, when the second Fenton reduction treatment is carried out, sulfuric acid is injected into the reduced iron precipitate which reacts with the iron salt to react with the iron salt, and the iron component in the precipitate is dissolved in the sulfuric acid to separate into iron salt solution and sludge, The iron phosphate solution is reused in each process requiring iron salt input, and the precipitate is dehydrated like a precipitate generated when it is treated by a biological treatment method or a Fenton oxidation treatment method, and is discharged and treated as a dehydrated cake.

Description

The Disposal of Dyeing Wastewater [

More particularly, the present invention relates to a dyeing wastewater treatment method, and more particularly, to a dyeing wastewater treatment method which comprises a step of adding a small amount of iron salt to a pretreatment step to perform primary pretreatment, neutralization, Thereby treating the dyeing wastewater.

The present invention has the effect of increasing the removal efficiency of organic matter and EG in the secondary biological treatment by performing the Fenton reduction treatment in the first pretreatment, and it is possible to reduce the chemicals used and reduce the treatment efficiency by performing the biological treatment and the tertiary Fenton reduction treatment , And it can be removed by performing 4th Fenton oxidation treatment with a small amount of organic substances and refractory pollutants and PVA which can not be removed even though the reaction rate is low even after the second biological treatment or the third Fenton reduction treatment. And the iron salts can be recovered and recycled from the iron salt reduced precipitate. Also, a part of the 4th Fenton oxidation treatment water is used to neutralize the first pretreatment water, thereby reducing the amount of the oxidizing agent used.

Since the dyeing wastewater changes depending on the seasonal trends and changes in consumer's desires, the production process changes accordingly, so it is difficult to specify the amount of various pollutants contained in the dyeing wastewater. However, The main characteristic of the dyeing wastewater flowing into the reactor is that it has a temperature of 40 to 80 ° C, a strong alkaline pH of about 8.5 to 10, a high COD and BOD concentration, a biodegradable material of starch and EG, Contains a variety of dyes that can be combined with colors to make it difficult to dissolve. It contains PVA, TPA, and some poisonous substances, which are chemically degradable contaminants.

 As a method of treating the pollutants in the dyeing wastewater having various characteristics as described above, there are a method of treating the biological treatment method and the refractory pollutants such as ozone oxidation, electrolysis, microwave irradiation, plasma utilization decomposition, photocatalytic oxidation Various methods disclosed in Korean Patent Publication.

In particular, methods such as ozone oxidation and electrolysis for treating degradation pollutants have been widely used as auxiliary treatment methods in some cases, not in the main treatment method, depending on the characteristics of the dyeing wastewater.

In order to treat the degradable pollutants stably and efficiently, the dyeing wastewater is first biologically treated, then the acid solution is added to the acidic solution for the purpose of the Fenton oxidation treatment, then the iron salt and the hydrogen peroxide are added to the solution, A method of oxidizing a dyeing wastewater Fenton which reacts a substance with an iron salt to precipitate and remove the precipitate as a trivalent iron salt is disclosed in Korean Patent Laid-Open Publication No. 10-1996-0031353 (Patent Registration No. 10-0145467).

The above-mentioned dyeing wastewater Fenton oxidation method has good treatment efficiency of the fouling-resistant pollutants. However, in order to enhance the strong acidification and oxidation power which are the Fenton oxidizing conditions of the whole dyeing wastewater, expensive chemicals such as sulfuric acid and hydrogen peroxide are required in a large amount, The poorly treated TPA and dyes are not easily oxidized and the treatment efficiency is low and the iron salts to be added can not be recycled so that all of the iron salt oxidation reaction precipitates become sludge and the amount of dehydrated cake is increased, In particular, it is difficult to remove the chromaticity.

To improve this, an alkaline solution is added to the incoming dyeing wastewater to elevate the pH to about 10.5 to 11, thereby forming a reducing state. The iron salt is then added to react the poorly decomposing contaminant with the iron salt to precipitate out the precipitate of the ferric iron salt, The removed dyeing wastewater is subjected to a biological treatment to remove organic substances and then discharged, and the iron salt precipitate is dissolved in sulfuric acid and regenerated as an iron salt solution for reuse. Korean Patent Publication No. 10-2013-0086598 (Patent Registration No. 10-01379374 ≪ / RTI >

The method of recovering the dyeing wastewater according to the present invention is not limited to the use of hydrogen peroxide, which is widely used in the Fenton oxidizing method, in order to produce a trivalent iron salt as compared with the dyeing wastewater Fenton oxidizing method described above. Which can be recovered and recycled, is advantageous in that it has good economical efficiency and good decomposition of chromaticity. However, firstly, it treats the degradable pollutants by the iron salt recovery method and adopts the second biological treatment method. Therefore, in the first Fenton reduction treatment, Part of the organic matter is mixed with iron salts to increase the amount of iron salt to treat the degradable pollutants and PVA which is difficult to be treated by biological treatment method or Fenton reduction treatment method is mixed into the discharged water and the quality of the final discharge water is deteriorated There is a problem.

SUMMARY OF THE INVENTION [0006] In order to solve the above problems,

By using the reducing ability of the alkaline dyeing wastewater to be introduced, it is pretreated with iron salt, and the organic and EG treatment efficiency is improved in the biological treatment facility by cutting off the complex intertwined refractory pollutant rings.

It is a further object of the present invention to provide a method and apparatus for treating organic wastewater with organic matter and EG in a dyeing wastewater by treating the pre-treated dyeing wastewater with a biological method, wherein the amount of iron salt added to the Fenton- And to reduce the EG from reducing the Fenton treatment efficiency.

It is a further object of the present invention to provide a method of treating a dyeing wastewater from which an organic matter has been removed with a Fenton reduction treatment method to oxidize Fenton to a degradable contaminant and easily remove a substance such as TPA which requires an expensive oxidizing agent such as hydrogen peroxide Reduce drug use, improve chromaticity, and regenerate and reuse iron salts in reduced iron precipitates.

It is another object of the present invention to provide a dyeing wastewater treatment method which is economical while improving the water quality of discharged water by removing PVA and the like which are not easily treated in the biological treatment method or the Fenton reduction treatment method in the dyeing wastewater, There is a purpose.

According to another aspect of the present invention, there is provided a method of treating dyeing wastewater,

A pre-treatment step (S10) of introducing dyeing wastewater (A) into the water collecting tank (110) and adding iron salts (Fe ₂ SO ₄ ) to combine iridescent contaminants in iron ions and dyeing wastewater to form flocs; A biological treatment step (S20) in which the dyeing wastewater (A) passed through the pretreatment step (S10) is introduced into the pH adjustment tank (210) and neutralized and then introduced into the aeration tank (220) The dyeing wastewater A via the biological treatment step S 20 is transferred to the reducing and regulating tank 320 to feed the iron salts and transferred to the reducing reaction tank 330 to be alkalized to remove iron deficiency and refractory pollutants in the dyeing wastewater A step (S30) of a Fenton reduction treatment to form a flock while bonding; The flocs generated in the Fenton reduction treatment step S30 are coagulated and precipitated and transferred to an acid reaction tank 610 to regenerate the solution as a ferrous salt solution under a strongly acidic environment and separate the supernatant and precipitate through a solid-liquid separator 630, An iron salt recovery step (S60) in which the iron salt solution is returned to the iron salt solution storage tank (640) for reuse as iron salt solution, and the precipitate is dehydrated and discharged; The dyeing wastewater A treated via the fenton reduction treatment step S30 has a discharge step S50 in which the dyeing wastewater A is conveyed to the neutralization reaction tank 510 to be neutralized and discharged.

Fenton Reducing Treatment Step (S30) Next, the dyeing wastewater A passed through the Fenton reduction treatment step (S30) is transferred to the oxidation control tank 420, and acidic solution is supplied to the oxidation tank 420 and transferred to the oxidation reaction tank 430 (S40); and the discharging step (S50) of discharging the dyeing wastewater (A) treated via the Fenton oxidation treatment step (S40) It is preferable to transfer it to the neutralization reaction tank (510) to neutralize it and discharge it.

The precipitate produced by precipitating the flocs generated in the biological treatment step S20 in the secondary flocculation and sedimentation tank 230, the precipitate produced in the iron salt recovery step S60, and the flock generated in the Fenton oxidation treatment step S40 And a dehydration step (S70) for dehydrating and discharging the precipitate produced by precipitating in the fourth flocculation and sedimentation tank (440) to the dehydrator (710).

A part of the dyeing wastewater A via the Fenton oxidation treatment step S40 is preferably transferred to the pH adjustment tank 210 and used to neutralize the dyeing wastewater A via the pre-treatment step S10.

The present invention as described above has an effect of increasing the removal efficiency of organic matter and EG in the second biological treatment by performing the fenton reduction treatment in the first pretreatment, It is effective to increase the efficiency. It is also possible to remove a trace amount of organic substances, refractory pollutants and PVA which are not easily removed even when subjected to the second biological treatment or the third Fenton reduction treatment by the fourth Fenton oxidation treatment The iron salts can be recovered and recycled from the iron salt reduced precipitate and a part of the 4th Fenton oxidation water can be used to neutralize the first pretreatment water to reduce the amount of the oxidizing agent used.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an overall flowchart of a dyeing wastewater treatment method according to the present invention
Fig. 2 is a device configuration diagram of the dyeing wastewater treatment method according to the present invention

[Figure 1]

As shown in FIG. 1, the method of treating dyeing wastewater according to the present invention is characterized in that the incoming dyeing wastewater is subjected to a pretreatment step S10, a biological treatment step S20, a Fenton reduction treatment step S30, a Fenton oxidation treatment step S40, The reduced iron precipitate precipitated in the Fenton reduction treatment step S30 is subjected to solid-liquid separation in the iron salt recovery step (S60), and the supernatant is regenerated as an iron salt to be recovered in the iron salt solution reservoir 640 And is reused in the pretreatment step S10, the Fenton reduction treatment step S30 and the Fenton oxidation treatment step S40, and the reduced precipitate is generated in the biological treatment step S20 and the Fenton oxidation treatment step S30 And the dehydration process is performed in the dehydration step (S70) like the precipitate and the iron oxide precipitate, and the respective facilities are integrally connected to each other.

On the other hand, a part of the treated water subjected to the Fenton oxidation treatment step (S40) can be used for biological treatment step S20, that is, to flow into the pH adjustment tank 210 of FIG. 2 and to neutralize the treated water through the pretreatment step S10 .

2, the biological treatment facility 200 of FIG. 2, and the Fenton reduction treatment step S30 are the same as the Fenton reduction treatment facility of FIG. 2 (FIG. 2). The pretreatment step S10 includes the pretreatment facility 100, the biological treatment step S20, The Fenton oxidation treatment step 400 of FIG. 2, the discharging facility 500 of FIG. 2, and the iron salt recovery step S60 of FIG. 2 are the same as the Fenton oxidation treatment facility 400 of FIG. The dehydrating step 600 and the dehydrating step S70 are performed in the dehydrating facility 700 of FIG.

[Figure 2]

As shown in FIG. 2, the dyeing wastewater A is introduced into the water collecting tank 110. The dyeing wastewater A has a temperature difference of about 25 ° C to 45 ° C and a pH of 8.5 to 11 according to the dyeing process, In order to uniformly adjust the dyeing wastewater (A) property to be treated, if the dye is temporarily stored in the water collecting tank (110) and agitated, the pH is homogenized to about 9 to 10, When the biodegradable waste water (A) is treated in the biological treatment facility (200) due to the degradable pollutant entangled with the organic matter, the biodegradable pollutant loop is long and the microorganism interferes with decomposition of EG or organic matter, The concentration of the iron salt necessary for treating the entire refractory pollutant present in the dyeing wastewater through the iron salt injecting nozzle 120 to the water collecting tank 110 is reduced to 30 to 30% The dyeing wastewater homogenized in the water collecting tank 210 is alkaline having a pH of about 9 to 10, so that the iron salt is reduced and the binding loops of the degradable contaminants combined with the organic matter are cut off. So that the biological treatment facility 200, which is a secondary treatment facility, increases the decomposition efficiency of organic substances and EG.

The pre-treated dyeing wastewater A flows into the biological treatment facility 200 and is adjusted to have a pH of 7 to 8 in the pH adjusting tank 210 and then flows into the aeration tank 220. While staying in the aeration tank 220 for a long time, The organic matter, starch, EG and the like in the dyeing wastewater A are decomposed by the microorganisms and the microorganism bodies and undissolved organic matter are precipitated in the second coagulating sedimentation tank 230 and are removed as precipitates by the action of the aerobic microorganisms (A) is a secondary treated dyeing wastewater from which organic matter has been removed.

The dyeing wastewater A from which the organic matter of the secondary flocculation and sedimentation tank 230 has been removed is introduced into the Fenton reduction treatment facility 300 and fed into the reduction treatment tank 320 from the iron salt input unit 310, The alkali solution is introduced from the alkali solution injector 340 so that the pH of the dyeing wastewater A can be reduced to an alkaline reducing atmosphere of 9.5 to 10.5, ^{2 +} components are strong alkaline flux is formed and then a reducing atmosphere due to SO ₄ ^2- groups separation I in the dyeing waste water quickly combined with degradable contaminants are particles grows faster aggregation, precipitation from the third agglomeration precipitation tank 350, the rear end The third treatment is the removal of the iron salt reduction precipitate containing the degradable pollutants, resulting in most of the degradation pollutants and the third treated dye waste water with the chromaticity removed.

On the other hand, iron (Fe ₂ SO ₄₎ from Fe ^{2 +} a functional part of the SO ₄ ^2- groups are again separated and the OH group and NaOH for Na ^{+ -} sikineunde group separation The separation of OH ^- groups decomposing the chromaticity of the discharged water by radical Chemistry do.

The tertiary treated dyeing wastewater A of the tertiary flocculation and sedimentation tank 350 flows into the Fenton oxidation treatment facility 400 and the acid solution is supplied from the acid solution feeder 410 in the oxidation control tank 420, The ferritic oxidation by the iron salt is strongly generated when the ferrous salt solution is fed into the oxidation tank 430 at the rear stage while maintaining the strongly acidic state of 2.5 to 3.5, and the refractory contaminants remaining in the tertiary treated dyeing waste water (A) PVA, which is not easily removed by a small amount of organic matter and biological treatment method and Fenton's reduction treatment method, is reacted to become flashed and becomes a fourth-treated stained waste water (A) to be removed as a precipitate in the third coagulation settling tank 440.

Since the fourth treated dyeing wastewater, which is the supernatant of the tertiary flocculation settling tank 4400, is purified wastewater having a pH of about 4 to 5.5, it is neutralized to a pH of 7.5 in the neutralization tank (500) (520) and finally discharged (B) to the outside of the dyeing wastewater treatment plant.

On the other hand, when the Fenton oxidation treatment is not necessary because the PVA or the like does not remain in the refractory pollutants of the incoming dyeing wastewater, the supernatant of the tertiary flocculation and sedimentation tank 350 is removed from the 500 ), Neutralized to pH 7.5, stored in the effluent water tank 520, and finally discharged (B) to the outside of the dyeing wastewater treatment plant.

In addition, the iron chloride reduced precipitate settled in the lower portion of the tertiary flocculation and sedimentation tank 350 still has an alkaline pH of 8.5 or more, although the strongly acidic iron salt reacted with the strong alkaline dyeing wastewater (A), and the iron salt- When the reaction mixture flows into the acid reaction tank 610 as the facility 600, the sulfuric acid reduced precipitate charged from the acid addition unit 620 installed on the acid reaction tank 610 is strongly acidified to a pH of about 1 to 2.5, (Fe ²⁺ ) component in the iron salt reduced precipitate is melted and eluted. The eluted iron component reacts with sulfuric acid and is regenerated again as a solution of iron (Fe ₂ SO ₄ ). In the acid reaction tank 610, When the precipitate is retained in the solid-liquid separator 630, the precipitate is separated into the iron salt reduced precipitate and the supernatant. The supernatant is an iron salt solution, and is stored in the iron salt solution reservoir 640, In Lee facilities 100, Fenton reduction treatment facility 300, the Fenton oxidation treatment facility 400 is reused as iron salts that need.

 The reduced precipitate separated and precipitated in the solid-liquid separator 630 is precipitated by the coagulation sedimentation tank 440 and the coagulation sedimentation tank 440, Dehydrated in the dehydrator 701, and then discharged to the outside of the dyeing wastewater treatment plant in a dehydrated cake state.

S10. Preprocessing step S20. Biological treatment step
S30. Fenton reduction processing step S40. Fenton oxidation step
S50. Discharge step S60. Iron salt recovery step
S70. Dehydration step
100. Pretreatment facility 110. Sink tank
120. Iron salt injection nozzle 200. Biological treatment facility
210. pH adjusting tank 220. Aeration tank
230. Second coagulation sedimentation tank 300. Fenton reduction treatment facility
310. Iron salt input unit 320. Reduction control tank
330. Reduction reaction tank 340. Alkaline solution injector
350. Third coagulation sedimentation tank 400. Fenton oxidation treatment facility
410. Acid solution feeder 420. Oxidation adjustment tank
430. Oxidation tank 440. Fourth coagulation settling tank
500. Discharge facility 510. Neutralization reaction tank
520. Discharged water tank 600. Iron salt recovery facility
610. Acid Reactor 620. Acid Feeder
630. Solid-liquid separator 640. Iron salt solution reservoir
700. Dehydration facility 710. Dehydrator

Claims (4)

In the dyeing wastewater treatment method,
A pre-treatment step (S10) of introducing dyeing wastewater (A) into the water collecting tank (110) and adding iron salts (Fe ₂ SO ₄ ) to combine iridescent contaminants in iron ions and dyeing wastewater to form flocs;
A biological treatment step (S20) in which the dyeing wastewater (A) passed through the pretreatment step (S10) is introduced into the pH adjustment tank (210) and neutralized and then introduced into the aeration tank (220)
The dyeing wastewater A via the biological treatment step S20 is transferred to the reduction regulating tank 320 to feed the iron salts and transferred to the reducing reaction tank 330 to be alkalized to remove the iron ion and the refractory contaminants in the dyeing wastewater Fenton reduction processing step (S30) for forming a flak while forming a flock;
The flocs generated in the Fenton reduction treatment step S30 are coagulated and precipitated and transferred to an acid reaction tank 610 to regenerate the solution as a ferrous salt solution under a strongly acidic environment and separate the supernatant and precipitate through a solid-liquid separator 630, An iron salt recovery step (S60) in which the iron salt solution is returned to the iron salt solution storage tank (640) for reuse as iron salt solution, and the precipitate is dehydrated and discharged;
The dyeing wastewater A passed through the Fenton reduction treatment step S30 is transferred to the oxidation control tank 420 so that the acid solution is injected into the oxidation reaction tank 430 and transferred to the oxidation reaction tank 430, (Step S40);
(S50) of transferring the dyeing wastewater (A) treated via the Fenton oxidation treatment step (S40) to a neutralization reaction tank (510) and neutralizing and discharging the dyeing wastewater (A).
The method of claim 1, wherein
The precipitate formed by precipitating the flocs generated in the biological treatment step (S20) in the secondary coagulating sedimentation tank (230)
The precipitate produced in the iron salt recovery step (S60)
And a dehydrating step (S70) of discharging the precipitate formed by precipitating the flocs generated in the Fenton oxidation treatment step (S40) in the fourth flocculation and sedimentation tank (440) and dehydrating the dehydrated water to the dehydrator (710) Processing method.
3. The method according to claim 1 or 2,
A part of the dyeing wastewater A via the Fenton oxidation treatment step S40 is transferred to the pH adjustment tank 210 and is used for neutralizing the dyeing wastewater A via the pretreatment step S10. Processing method.
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