KR101036880B1 - Wastewater recycling apparatus and method of preparing ultrapure water using reusable water prepared by the same - Google Patents

Abstract

PURPOSE: An apparatus for reusing wasted water and a method for manufacturing ultra-pure water are provided to effectively eliminate non-degradable low molecule organic materials and improve the quality of the ultra-pure water. CONSTITUTION: An apparatus for reusing wasted water includes a reverse osmotic membrane unit(420) and a catalyst oxidation unit(440). The reverse osmotic membrane unit processes introduced water. The catalyst oxidation unit includes catalyst and oxidant and decomposes organic materials in processed water from the reverse osmotic membrane. The catalyst is a support catalyst. At least one transition metal of Fe and Cu and at least one metal selected from a group including Al, Ce, Mn, and Zn are used for the catalyst respectively as a main catalyst and an auxiliary catalyst. The oxidant reacts with the catalyst to generate radical.

Description

Wastewater recycling apparatus and method of preparing ultrapure water using reusable water prepared by the same}

Disclosed are a wastewater recycling apparatus and a method of producing ultrapure water. More specifically, a wastewater recycling apparatus including a reverse osmosis membrane apparatus and a catalytic oxidation apparatus, and a method for producing ultrapure water using recycled water produced by the wastewater recycling apparatus are disclosed.

Recently, the use of ultrapure water is rapidly increasing due to the expansion of semiconductor manufacturing apparatuses. Accordingly, the necessity of securing a new water source is increasing. As a solution to this problem, a wastewater recycling method for recycling wastewater treatment plant as raw water of an ultrapure water production apparatus has been developed. As a technology for recycling wastewater and sewage, a technique for further purifying the treated water of the sewage treatment plant using a membrane separation technique such as a reverse osmosis device is known. Reverse osmosis devices are effective in removing ionic substances in water and in removing TOC (total organic carbon). However, when refining semiconductor wastewater containing various kinds of organic matter using only reverse osmosis apparatus, it is known that reusable water having a water quality that can be used as raw water of ultrapure water production equipment cannot be obtained. The reason is that the reverse osmosis device cannot efficiently remove low-degradability low molecular organic substances such as acetone contained in semiconductor wastewater. Existing ultrapure water production facilities have a lot of difficulties in treating such hardly decomposable low molecular weight organic materials. Thus, there is a need for a new process that can efficiently remove these low molecular weight organics.

In general, there are two methods for removing low molecular weight organic substances: adsorption using activated carbon and oxidation using an advanced oxidation process. Adsorption using activated carbon has a disadvantage in that the activated carbon has a limited adsorption capacity, and thus the activated carbon must be periodically regenerated or exchanged. In addition, the advanced oxidation process using UV or ozone has a high initial investment and operating costs, and difficult operation. Accordingly, there is a demand for the development of new technologies that can economically and efficiently reuse semiconductor wastewater while meeting the increasing demands for environmental protection.

One embodiment of the present invention provides a wastewater recycling apparatus comprising a reverse osmosis membrane device and a catalytic oxidation device.

Another embodiment of the present invention provides a method of producing ultrapure water using recycled water produced by the wastewater recycling apparatus.

One aspect of the invention,

Reverse osmosis membrane device for treating influent; And

The organic material in the treated water discharged from the reverse osmosis membrane device is decomposed by catalytic oxidation, thereby providing a wastewater recycling apparatus having a catalytic oxidation device including a catalyst and an oxidizing agent.

The influent may be at least one treatment of the wastewater discharged from the semiconductor manufacturing apparatus.

The catalyst may be a supported catalyst supported on a porous carrier.

The catalyst may comprise at least one transition metal.

The catalyst may include at least one transition metal of Fe and Cu as the main catalyst.

The content of the main catalyst may be 0.12 to 0.62% by weight based on the weight of the porous carrier.

The catalyst may further include at least one metal selected from the group consisting of Al, Ce, Mn and Zn as cocatalysts.

The content of the cocatalyst may be more than 0% by weight and 10% by weight or less based on the weight of the main catalyst.

The porous carrier may include at least one compound selected from the group consisting of activated carbon, zeolite, ion exchange resin, and alumina.

The oxidant may include at least one compound of hydrogen peroxide and ozone.

Influent water of the catalytic oxidation device may be maintained at pH 3 or less.

The catalytic oxidation device may include a plurality of catalytic oxidation tanks connected in series with each other.

Another aspect of the invention,

Provided is a method for producing ultrapure water using recycled water produced by the wastewater recycling apparatus.

According to one embodiment of the present invention, by including a reverse osmosis membrane device and a catalytic oxidation device can be provided a waste water recycling apparatus capable of producing recycled water having a water quality enough to be used as raw water of the semiconductor ultrapure water production apparatus. In addition, the wastewater recycling apparatus can produce recycled water containing a low TOC at the level of 100 μg / L. In addition, the wastewater recycling apparatus can efficiently remove the hardly decomposable low molecular weight organic substance having a molecular weight of 100 or less. These low molecular weight organic materials are materials that are not removed from the existing ultrapure water production apparatus, and are substances that are considered as a cause of deterioration of water quality in the production of ultrapure water using recycled water.

According to another embodiment of the present invention, a method for producing ultrapure water using recycled water produced by the wastewater reuse device may be provided.

1 is a view schematically illustrating a water circulation path of a semiconductor manufacturing apparatus including an apparatus for recycling wastewater and an ultrapure water manufacturing apparatus connected thereto according to an embodiment of the present invention.
2 is a view schematically showing an apparatus for recycling wastewater and an ultrapure water producing apparatus connected thereto according to an embodiment of the present invention.
3 is a view showing an embodiment of the catalytic oxidation device included in the wastewater recycling apparatus of FIG.
4 is a view showing an embodiment of the ultrapure water producing apparatus of FIG.

Next, with reference to the drawings will be described in detail with respect to the wastewater recycling apparatus and the method for producing ultrapure water using the recycled water produced by the wastewater recycling apparatus according to an embodiment of the present invention.

FIG. 1 is a view schematically illustrating a water circulation path of a semiconductor manufacturing apparatus 200 including a wastewater recycling apparatus 400 and an ultrapure water apparatus 100 connected thereto according to an embodiment of the present invention.

Referring to FIG. 1, after the industrial water is supplied to the ultrapure water producing apparatus 100 and purified into ultrapure water, it is used as raw water of the semiconductor manufacturing apparatus 200. TOC concentration and conductivity of the industrial water may be 1 ~ 1.5mg / L and 150 ~ 200μS / cm respectively. The TOC concentration and the specific resistance of the ultrapure water are 1 µg / L or less and 18.1 Pa · cm or more, respectively.

Wastewater discharged from the semiconductor manufacturing apparatus 200 (hereinafter, also referred to as semiconductor wastewater) is purified by the wastewater treatment apparatus 300 to generate primary treated water, and a part of the primary treated water is a wastewater reuse apparatus 400. The rest is discharged to rivers, etc.

In the wastewater recycling apparatus 400, organic substances (particularly, low molecular weight organic substances) and the like in the primary treated water are further removed to generate secondary treated water having a similar water quality to the industrial water. The TOC concentration and conductivity of the secondary treated water may be 40-50 μg / L and 400 μS / cm or less, respectively. The reason why the conductivity of the secondary treated water is higher than that of the industrial water is that acid is contained in the secondary treated water. The acid is added to adjust the pH of the treated water (eg, RO treated water) of the wastewater recycling apparatus 400. In the present specification, "low molecular weight organic material" means an organic material having a molecular weight of 100 or less, such as acetone or isopropyl alcohol (IPA).

2 is a view schematically showing an apparatus for recycling wastewater 400 and an ultrapure water producing apparatus 100 connected thereto according to an embodiment of the present invention.

2, the wastewater recycling apparatus 400 according to an embodiment of the present invention is a micro-filter (MF) device 410, reverse osmosis (RO) device 420, reverse osmosis (RO) treatment tank ( 430 and the catalytic oxidation apparatus 440.

The MF apparatus 410 removes contaminants such as colloidal particles, suspensions, algae and bacteria of 60 μm or more from the primary treated water of FIG. 1, and may include a membrane (not shown) having a pore size of 50 μm. Can be.

The RO device 420 removes a small solute having a molecular weight of about 10 to 1000 from the treated water discharged from the MF device 410, and may include a membrane (not shown) having a pore size of 3 to 10 mm 3. RO concentrated water and RO treated water are discharged from the RO device 420, and the RO treated water is sent to the RO treated water tank 430 and supplied to the catalytic oxidation device 440 which will be described later, and the RO concentrated water is drained. Is sent). The percentage obtained by dividing the flow rate of the RO treated water by the flow rate of the primary treated water flowing into the RO apparatus 420 is called a recovery rate. The RO device 420 may be operated, for example, at a recovery rate of 80% or more. The TOC concentration and conductivity of the RO treated water may be 100 to 200 µg / L and 150 to 200 µS / cm, respectively. Unlike the TOC of the industrial water, the TOC of the RO-treated water contains a large amount of low-molecular organic substances, and when it is used as raw water of the ultrapure water producing system 100, ultrapure water of desired water quality cannot be obtained (see Comparative Example 4). ). That is, neither the RO apparatus 420 nor the ultrapure water producing system 100 can effectively remove the low molecular organic material in the raw water.

The RO treated water tank 430 may be omitted, and the RO treated water is directly supplied to the catalytic oxidation device 440.

The catalytic oxidation device 440 decomposes organic materials in the RO treated water by catalytic oxidation, and includes a catalyst and an oxidizing agent.

The catalyst may be a supported catalyst supported on a porous carrier.

The porous carrier may include at least one compound selected from the group consisting of activated carbon, zeolite, ion exchange resin, and alumina.

The catalyst may comprise at least one transition metal. The catalyst may include at least one transition metal of Fe and Cu as the main catalyst. The content of the main catalyst may be 0.12 to 0.62% by weight based on the weight of the porous carrier. When the content of the main catalyst is less than 0.12% by weight based on the weight of the porous carrier, the amount of the active metal is small enough to decompose the organic material sufficiently, when exceeding 0.62% by weight, the radical radicals generated decompose the organic material. Hydroxide radicals can be consumed by reacting with each other without degrading the removal efficiency of organic materials.

In addition, the catalyst may further include at least one metal selected from the group consisting of Al, Ce, Mn and Zn as a promoter. The content of the cocatalyst may be more than 0% by weight and 10% by weight or less based on the weight of the main catalyst. When the content of the promoter is within the above range, the role of the promoter can be sufficiently exhibited while maintaining the effect of the main catalyst.

The configuration of the catalyst is not limited to the main catalyst / cocatalyst combination, and various other combinations are possible.

An example of a method for supporting the catalyst on a porous carrier is as follows. That is, the porous carrier is washed with an acidic solution and then rinsed sufficiently with distilled water. In addition, a metal salt containing a metal to be used as a catalyst is dissolved in distilled water to prepare an aqueous solution of metal salt of 1 to 10% by weight. Then, the porous carrier is impregnated with the aqueous metal salt solution. The impregnated porous carrier is then dried (eg 50 ° C.) and sintered (eg 150-300 ° C.).

The oxidant may include at least one compound of hydrogen peroxide and ozone. However, ozone requires a separate ozone generating device, and it is more preferable to use hydrogen peroxide, which is known to reduce the radical generation efficiency. The amount of the oxidant added is sufficient to be 30 times the concentration of TOC contained in the inflowing wastewater. When hydrogen peroxide (H ₂ O ₂ ) is used as the oxidizing agent, the hydrogen peroxide is in contact with the catalyst at a predetermined pH condition (for example, pH ≤ 3) to generate radicals, and the radicals are treated with water (RO). The low molecular organic substance in the treated water or the treated water of the catalytic oxidation tank 443) is oxidatively decomposed.

Wastewater recycling apparatus 400 according to an embodiment of the present invention may include a plurality of catalytic oxidation tank (for example, 443 and 444 of FIG. 3) connected in series.

3 is a view showing an embodiment of the catalytic oxidation device 440 included in the wastewater recycling apparatus 400 of FIG.

Referring to FIG. 3, the catalytic oxidation apparatus 440 may include an oxidant reservoir 441, an acid reservoir 442, and two catalytic oxidation tanks 442 and 443 connected in series with each other.

The oxidant of the oxidant reservoir 441 is injected into the front end of the inline mixers IM ₁ and IM ₂ by the magnetic pumps P _2A and P _2B and then treated with water (RO) in the inline mixers IM ₁ and IM ₂ . Treated water or catalytic oxidation tank 442) and mixed with acid.

Acid of the acid reservoir 442 is injected into the front end of the inline mixers IM ₁ and IM ₂ by the magnetic pumps P _3A and P _3B and then treated in the inline mixers IM ₁ and IM ₂ . Mixed with water and oxidizing agent. The magnetic pump P _3A is controlled by the pH value measured at the rear end of the inline mixer IM ₂ , and the magnetic pump P _3B is controlled by the pH value measured at the rear end of the inline mixer IM ₁ . By the magnetic pumps P _3A and P _3B , the pH value in the water to be treated can be adjusted to 3 or less to maintain a high oxidizing ability of the oxidant. The acid may include at least one inorganic acid selected from the group consisting of nitric acid, hydrochloric acid, perchloric acid, phosphoric acid and sulfuric acid. In the case of an organic acid, since it is an organic substance by itself and becomes a pollution source of to-be-processed water, it is not preferable.

The RO treated water is supplied to the inline mixer IM ₁ by a pump P1, mixed with the oxidizing agent and the acid, and then supplied to the catalytic oxidation tank 443.

The catalytic oxidation tank 443 may be filled with a supported catalyst on which a catalyst is supported on a porous carrier. In the catalytic oxidation tank 443, as described above, the oxidative decomposition reaction of the organic substances (especially low molecular organic substances) contained in the water to be treated occurs.

At the rear end of the catalytic oxidation tank 443, the catalytic oxidation tank 444 is connected in series to further oxidatively decompose organic substances in the water to be treated. The specific configuration of the catalytic oxidation tank 444 may be the same as or similar to the catalytic oxidation tank 443.

The treated water discharged from the catalytic oxidation tank 444 (that is, the secondary treated water of FIG. 1) may be reused in the ultrapure water producing apparatus 100.

In FIG. 3, reference numerals M ₁ , M _2A , M _2B , M _3A , and M _3B are motors, AI 101 is an indicator, and AE 101 is a measuring instrument.

4 is a view showing an embodiment of the ultrapure water producing apparatus 100 of FIG.

Referring to FIG. 4, the ultrapure water producing apparatus 100 may include a pretreatment block 110, a make-up block 120, and a polishing block 130.

The pretreatment block 110 removes suspended matter, organic matter, dissolved solids and gas in the secondary treated water. Pretreatment block 110 is activated carbon adsorption tank 111 for adsorbing and removing impurities, MF apparatus 112 for filtering and removing suspended solids, cation exchange tank 113 for removing cations and adjusting pH and CO ₂ Degassing tank 114 may be included.

The make-up block 120 further removes impurities such as organic substances, dissolved solids, and ions remaining in the treated water discharged from the pretreatment block 110. The make-up block 120 includes a RO apparatus 121 for filtering and removing impurities, a UV treatment tank 122 for decomposing and removing trace organic materials, a mixed ion exchange tank 123 for removing trace ions, and dissolved oxygen. It may include a vacuum degassing tank 124 to remove. As used herein, the term "mixed ion exchange tank" refers to a resin tower filled with a cation exchange resin and an anion exchange resin.

The polishing block 130 further removes fine organic substances, oxidants, ions and fine particles remaining in the treated water discharged from the make-up block 120 to produce ultrapure water. Polishing block 130 is a UV treatment tank 131 that decomposes and removes trace amounts of organic substances, anion exchange vessel 132 that removes trace amounts of anions and oxidants (eg hydrogen peroxide), mixed phase ion exchange to remove trace amounts of ions Bath 133 and ultra-filter (UF) device 134 for filtering and removing microparticles.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these embodiments.

Example

Example  1 to 14

(Removal of Low Molecular Organic Matter Using Catalyst Supported on Activated Carbon and Hydrogen Peroxide: Standard Solution)

The removal rate of acetone and IPA, which are low molecular weight organic materials, was investigated using hydrogen peroxide as an oxidant and various kinds of supported catalysts as shown in Table 1 below. Activated carbon (Samcheonri activated carbon, SLS-100) was used as the porous carrier, and the total content of the catalyst (ie, the content of the main catalyst + the content of the cocatalyst) was 0.62 wt% based on the weight of the porous carrier. In addition, when the promoter was used in addition to the main catalyst, the content of the promoter was 10% by weight based on the weight of the main catalyst. First, 200 mL of deionized water and 0.3 g of each supported catalyst were added to a 250 mL plastic container. Thereafter, nitric acid was added to the vessel to adjust the pH of the vessel contents to three. Thereafter, hydrogen peroxide was added to the vessel, such that the concentration of hydrogen peroxide in the water to be treated (ie, the vessel contents) was 5 mg / L. This corresponds to about 1.5 times the theoretical requirement of hydrogen peroxide required for complete decomposition of the added acetone, which is an appropriate amount to confirm the activity of the catalyst. Subsequently, acetone was further added to the vessel, so that the acetone concentration in the water to be treated was 300 µg / L. The vessel contents were mixed for 30 minutes using a stirrer (DK, Wisekskake SHR-2D). Thereafter, the concentration of acetone in the contents of the container was measured using gas chromatography, and the removal rate of acetone was calculated and shown in Table 1 below. In addition, the removal rate investigation of IPA was also performed by the same method as the said method. In this case, however, the amount of IPA added was 150 µg / L.

Comparative example  One

The removal rate of acetone and IPA was investigated in the same manner as in Examples 1 to 14 except that activated carbon was used instead of the supported catalyst. That is, in Comparative Example 1, no catalyst was used.

division Main catalyst Promoter Acetone Removal Rate
(weight%) IPA removal rate
(weight%) Example 1 Cu - 41.7 100 Example 2 Fe - 37.5 100 Example 3 Mn - 33.9 100 Example 4 Co - 31.0 100 Example 5 Fe Al 58.6 100 Example 6 Fe Cu 53.3 100 Example 7 Fe Mn 48.3 100 Example 8 Fe Ce 45.1 100 Example 9 Fe Zn 47.4 100 Example 10 Cu Fe 51.8 100 Example 11 Cu Al 56.8 100 Example 12 Cu Ce 52.1 100 Example 13 Cu Mn 47.7 100 Example 14 Cu Zn 46.3 100 Comparative Example 1 - - 27.9 28

Referring to Table 1, it was found that the removal rate of acetone and IPA of Examples 1 to 14 using the supported catalyst was higher than that of Comparative Example 1 using only activated carbon.

Example  15

(Removal of Organic Matter Using Catalyst Supported on Activated Carbon and Hydrogen Peroxide: Actual Wastewater Use)

The actual wastewater discharged from the commercial semiconductor manufacturing process was supplied to the wastewater recycling apparatus having the configuration of FIG. 2 and treated. In actual wastewater, the average concentration of TOC was 103 µg / L, the acetone concentration was 2.3 µg / L, and the conductivity was 150 µS / cm. In addition, the configuration of the catalytic oxidation apparatus provided in the wastewater recycling apparatus was the same as that of FIG. 3, and the same supported catalyst as used in Example 5 was used. In addition, Woongjin's MF module (pore size: 50㎛, Cartridge type) was used as the MF device, and Woongjin's RE-2540Fe-n (Spiral wound type) was used as the RO device. In addition, the serially connected one-stage catalytic oxidation tank and the two-stage catalytic oxidation tank were each filled with 30 g of a supported catalyst in a 100 ml column, and the treated water from each catalytic oxidation tank (ie The residence time of the liquid mixture) was maintained at 10 minutes each. In addition, nitric acid was added to adjust the pH of the treated water to 3. In addition, hydrogen peroxide was continuously added to each of the catalytic oxidation tanks, but was added so that the concentration of hydrogen peroxide in the water to be treated was 3 mg / L. After confirming the treated water discharged from each catalytic oxidation tank with a TOC measuring instrument (GE, Sievers-900) and reaching a steady state, the concentration of hydrogen peroxide, TOC and acetone contained in the treated water were measured. It is shown in Table 2 below. Here, the concentration of hydrogen peroxide was measured using a Chemets ampoule of CHEMETRICS, and the concentration of acetone was measured using gas chromatography (GC).

1 stage catalytic oxidation tank 2-stage catalytic oxidation tank Influent Runoff Influent Runoff Operating conditions Retention time (minutes) 10 10 pH 3.1 3.1 3.1 3.1 The hydrogen peroxide concentration _- (mg / L) 3 0.5 3 0.5 Driving results TOC concentration
(Μg / L) 103 38 38 34 Acetone concentration
(Μg / L) 2.3 0.67 0.67 0.39

Referring to Table 2, the removal rate of TOC and acetone by the first stage catalytic oxidation tank was about 63% and about 71%, respectively, and the hydrogen peroxide introduced into the first stage catalytic oxidation tank was removed by 80% or more. In addition, the total removal rate of TOC and total removal rate of acetone by the 1st stage and 2nd stage catalytic oxidation tank were about 67% and about 83%, respectively.

Example  16

(Production of ultrapure water)

The recycled water prepared in Example 15 (ie, the effluent of the two-stage catalytic oxidation tank) was treated by supplying it to the ultrapure water producing apparatus having the configuration of FIG. 4 and having a treatment capacity of 1 m ³ / hr. Here, Samchully activated carbon company's SLS-100 was used for the activated carbon adsorption tank of the pretreatment block, Woongjin's MF module (pore size: 1㎛, Cartridge type) was used as the MF device, and Rohm & Hass Corp. was used as the cation exchange tank. IR120H was used, and a degassing tank was used to connect Liqui-cell's Extra-flow to Air Hi-Tech's Air-blower. In addition, Woongjin's RE-8021 (Spiral wound type) was used as the RO device of the make-up block, Aquafine's MP-2 was used as the UV treatment tank, and Rohm &Hass's UP6040 was used as the mixed phase ion exchange tank. As the vacuum degassing tank, an extra-flow of Liqui-cell was connected to the DHF2 vacuum pump of Hyosung. In addition, Aquafine's MP-2 was used as the UV treatment tank for the polishing block, Rohm &Hass's UP4000 was used as the anion exchanger, Rohm &Hass's UP6040 was used as the mixed ion exchanger, and Asahi's as the UF device. OLT-3026 was used. The TOC concentration in the final treated water discharged from the ultrapure water production apparatus is analyzed every 30 minutes, and after reaching a steady state, the TOC concentration included in the final treated water and the electrical resistance of the final treated water are measured. It is shown in Table 3 below. At this time, the TOC concentration and electrical resistance were measured using Anatel XP-1000.

Comparative example  2

(Production of ultrapure water)

Ultrapure water was prepared in the same manner as in Example 16, except that industrial water (average TOC concentration: 1350 µg / L, average electrical conductivity: 175 µS / cm) was used instead of reused water. TOC contained in the ultrapure water and the electrical resistance of the ultrapure water were measured, and the results are shown in Table 3 below.

Comparative example  3

(Production of ultrapure water)

An ultrapure water was produced in the same manner as in Example 16, except that semiconductor wastewater (average TOC concentration: 1500 µg / L, average electrical conductivity: 4750 µS / cm) discharged from the semiconductor manufacturing apparatus was used instead of reused water. It was. TOC contained in the final treated water and the electrical resistance of the final treated water was measured and the results are shown in Table 3 below.

Comparative example  4

(Production of ultrapure water)

The above-mentioned operation was carried out except that the RO treated water (average TOC concentration: 105 µg / L, average electrical conductivity: 175 µS / cm) manufactured in the RO apparatus of Example 15 was used instead of the recycled water prepared in Example 15. Ultrapure water was tried in the same manner as in Example 16. TOC contained in the final treated water and the electrical resistance of the final treated water was measured and the results are shown in Table 3 below.

division Example 16 Comparative Example 2 Comparative Example 3 Comparative Example 4 Semiconductor ultra pure water quality standards TOC concentration
(Μg / L) 0.774 0.753 5.11 4.4 <1 Electrical resistance
(Cm) 18.2 18.2 16.5 18.2 <18.1

Referring to Table 3, the final treated water prepared in Example 16 was found to meet the water quality standards of semiconductor ultrapure water almost the same as the case of Comparative Example 2 using the industrial water. On the other hand, the final treated water prepared in Comparative Example 3 (using semiconductor wastewater) and Comparative Example 4 (using RO treated water) did not meet the water quality standards of semiconductor ultrapure water. In particular, in the case of Comparative Example 3 using semiconductor wastewater, the production flow rate of the treated water decreased to 0.73 m ³ / hr. In contrast, in the case of Example 16 using the final treated water prepared in Example 16 and Comparative Example 2 using the industrial water, the production flow rate of the treated water was maintained at 1 m ³ / hr, respectively. In addition, in the case of Comparative Example 4 using RO treated water, the electrical resistance criterion was satisfied, but the TOC concentration criterion was not satisfied. As described above, the low molecular organic matter in the semiconductor wastewater could not be effectively removed by the RO device alone. Because.

Although preferred embodiments of the present invention have been described above with reference to the drawings and embodiments, these are merely exemplary, and various modifications and equivalent other embodiments are possible to those skilled in the art. You will understand. Therefore, the protection scope of the present invention should be defined by the appended claims.

100: ultrapure water production apparatus 110: pretreatment block
111: activated carbon adsorption tank 112, 410: MF apparatus
120: Make-Up blocks 121, 420: RO unit
113, 123, 132, 133: ion exchange tank 114, 124: degassing tank
122, 131: UV treatment tank 130: Polishing block
134: UF device 200: semiconductor manufacturing device
300: wastewater treatment apparatus 400: wastewater recycling apparatus
430: RO treatment tank 440: catalytic oxidation device
441: oxidant reservoir 442: acid reservoir
443, 444: catalytic oxidation tank

Claims (12)

Reverse osmosis membrane device for treating influent; And
Decomposing the organic material in the treated water discharged from the reverse osmosis membrane device by catalytic oxidation, comprising a catalytic oxidation device including a catalyst and an oxidizing agent,
The catalyst is a supported catalyst in which at least one transition metal of Fe and Cu as a main catalyst and at least one metal selected from the group consisting of Al, Ce, Mn and Zn as a promoter are supported on a porous carrier,
And said oxidant reacts with said catalyst to produce radicals. The method of claim 1,
The inflow water is a wastewater recycling apparatus that has at least once treated the wastewater discharged from the semiconductor manufacturing apparatus. delete delete delete The method of claim 1,
Content of the main catalyst is 0.12 ~ 0.62% by weight based on the weight of the porous carrier waste water recycling apparatus. delete The method of claim 1,
The amount of the promoter is greater than 0% by weight 10% by weight based on the weight of the main catalyst recycling apparatus. The method of claim 1,
The porous carrier is waste water recycling apparatus comprising at least one compound selected from the group consisting of activated carbon, zeolite, ion exchange resin and alumina. The method of claim 1,
Influent water of the catalytic oxidation device is maintained at pH 3 or less wastewater recycling apparatus. The method of claim 1,
The catalytic oxidation device is a wastewater recycling apparatus comprising a plurality of catalytic oxidation tanks connected in series with each other. A method for producing ultrapure water using recycled water produced by the wastewater recycling apparatus according to any one of claims 1, 2, 6, and 8-11.

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