KR101790875B1 - System for treatment of ultra pure water including reuse of waste water - Google Patents

Abstract

The present invention relates to an ultra pure water treatment system including reuse of wastewater, and more particularly, to a process for reusing relatively high purity wastewater discharged from an industrial facility such as a semiconductor manufacturing factory where ultrapure water is used for ultrapure water production, (B), and organic matter (TOC) contained in the wastewater by reducing the amount of the ultrapure water production process by reducing the content of silica (Si), boron (B) Processing system.
An ultrapure water treatment system including waste water reuse according to the present invention includes: a first storage tank for storing raw water; A pretreatment unit for pretreating the raw water introduced from the first storage tank; A second storage tank for storing the pretreated water in the pretreatment unit; A pure water treatment unit for treating the treated water flowing from the second storage tank with pure water; An ultrapure water treatment unit for treating the pure water treated in the pure water treatment unit with ultrapure water; An industrial facility in which ultra pure water treated in the ultra pure water processing unit is used; An electrochemical treatment unit for treating ultrapure water discharged from the industrial facility through an electrochemical treatment process and sending it to the second storage tank; .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an ultra pure water treatment system including waste water reuse,

The present invention relates to an ultra pure water treatment system including reuse of wastewater, and more particularly, to a process for reusing relatively high purity wastewater discharged from an industrial facility such as a semiconductor manufacturing factory where ultrapure water is used for ultrapure water production, (B), and organic matter (TOC) contained in the wastewater by reducing the amount of the ultrapure water production process by reducing the content of silica (Si), boron (B) Processing system.

High-value-added industrial processes such as semiconductor manufacturing processes and drug manufacturing processes use a large amount of ultrapure water.

Ultrapure water is used to wash impurities from the chemicals and product surface in the manufacturing process and requires the most stringent quality in the semiconductor manufacturing process, which can cause great problems in product performance such as electrical conductivity change due to impurities.

That is, a wafer or a substrate in a process such as a cleaning process is often treated with water, and as a single process, the wafer remains exposed for a longer time than in the air.

Therefore, the water used in the production of such a semiconductor device can be a source of pollution by itself because water contaminants such as water-soluble minerals, particles of impurities and bacteria in the water are dissolved or dispersed in water.

Fig. 1 shows the ultrapure water production process disclosed in the Construction Technology Newspaper (December 23, 2013) as a prior art.

Referring to FIG. 1, the ultrapure water production process according to the related art includes a pre-treatment process, a pure water treatment process, and an ultrapure water treatment process.

Various water treatment processes are involved in the process configuration even if the target elimination products are duplicated in order to stably maintain the final water quality, and the ultrapure water produced through such a process is used as the semiconductor process water.

On the other hand, as the concentration of semiconductors has increased in recent years, the required water quality and demand of ultrapure water have been rapidly increasing, and a corresponding change in the ultrapure water production process is required.

In addition, as the global water shortage becomes serious, the importance of securing various water resources and reusing water is emphasized.

Therefore, wastewater reuse is becoming common in the ultrapure water process.

The wastewater used in the ultra pure water process can be said to be high purity compared with general industrial wastewater, but it contains a large amount of silica (Si), boron (B) and organic matter (TOC) More rigorous processing is required.

As mentioned above, in order to meet the higher water quality requirements and wastewater reuse, treatment standards must be met through efficient response to substances that are difficult to process only by conventional processes.

In accordance with this, the reused water is pretreated and recovered in the present process, and effective process operation can be performed by applying a process suitable for removing impurities contained in a large amount in the reused water.

However, the characteristics of the ultrapure wastewater vary depending on the stage of the manufacturing process, so the recovery rate and efficient process design according to the number of reused water should be premised.

As a conventional technique for reusing such ultrapure wastewater, Korean Patent Registration No. 10-0509320 (issued on September 5, 2005) discloses a method for highly pure water production and wastewater reuse in a display component manufacturing process.

The prior art includes a process for producing ultrapure water through a chain effect of various treatment processes. In particular, the conventional process includes a process of blending wastewater generated in a process with raw water, treating the wastewater with a purified water, and reusing it.

However, the above-mentioned prior art has the effect of reducing the total amount of water consumed, but does not include an efficient operation method for the properties of wastewater. In some cases, in the case of high purity wastewater close to pure water, It is rather inefficient, and there is a problem that a pretreatment cost more than necessary is generated.

It is an object of the present invention to provide an ultrapure water treatment system capable of undergoing differentiated wastewater reuse process according to the characteristics of ultrapure water wastewater. In particular, by treating the reused ultra pure wastewater with electrochemical methods, the content of silica (Si), boron (B) and organic matter (TOC) contained in the wastewater is lowered to reduce the load on the ultrapure water production process, Which is capable of reusing waste water.

It is another object of the present invention to provide a method and an apparatus for purifying water by injecting an alkaline component into an electrochemical treatment process to achieve a high removal rate of silica (Si), boron (B) and the like through pH control, Which is capable of reducing the amount of chemicals injected for high removal rates of silica (Si) and boron (B) in a reverse osmosis process of a pure water treatment section.

According to an aspect of the present invention, there is provided an ultrapure water treatment system comprising: a first storage tank for storing raw water; A pretreatment unit for pretreating the raw water introduced from the first storage tank; A second storage tank for storing the pretreated water in the pretreatment unit; A pure water treatment unit for treating the treated water flowing from the second storage tank with pure water; An ultrapure water treatment unit for treating the pure water treated in the pure water treatment unit with ultrapure water; An industrial facility in which ultra pure water treated in the ultra pure water processing unit is used; An electrochemical treatment unit for treating ultrapure water discharged from the industrial facility through an electrochemical treatment process and sending it to the second storage tank; .

In addition, the ultrapure water treatment system including waste water reuse according to the present invention is characterized in that the electrochemical treatment process in the electrochemical treatment unit is an electrodeposition process, a capacitive deionization process or an electrocoagulation process .

In addition, the ultrapure water treatment system including waste water reuse according to the present invention is characterized in that the pure water treatment section includes a reverse osmosis process.

In addition, the ultra pure water treatment system including waste water reuse according to the present invention is characterized in that the alkaline component is injected into the ultrapure water wastewater into which the electrochemical treatment unit is introduced.

In addition, the ultrapure water treatment system including waste water reuse according to the present invention includes: a filtration processing unit for filtering ultrapure wastewater discharged from the industrial facility through a filter to be sent to the first storage tank for blending with raw water; A mixing treatment unit for directly feeding ultrapure wastewater discharged from the industrial facility to the first storage tank and blending the wastewater with raw water; A reuse control unit for controlling ultrapure water discharged from the industrial facility to pass through either the electrochemical treatment unit, the filtration treatment unit or the mixing treatment unit; And further comprising:

Further, in the ultra pure water treatment system according to the present invention, the reuse control unit controls the ultrapure water wastewater to pass through the electrochemical treatment unit when the conductivity of the ultrapure water wastewater discharged from the industrial facility is less than a set reference value .

The ultra pure water treatment system according to the present invention is characterized in that when the conductivity of the ultrapure water wastewater discharged from the industrial facility is equal to or greater than a predetermined reference value and the amount of solids per unit volume is equal to or greater than a set reference value, And controls the filter to pass through the filter processing unit.

According to the above-described structure, the ultra pure water treatment system including the reuse of wastewater according to the present invention uses an electrochemical treatment method for reutilization of ultrapure wastewater, so that there is no chemical use unlike the conventional technology using an ozone process and an ion exchange resin It is also possible to reduce the load of the ultrapure water production process by effectively reducing the content of silica (Si), boron (B) and organic matter (TOC) contained in the wastewater, There is an advantage of securing water quality.

In addition, the ultra pure water treatment system including waste water reuse according to the present invention not only achieves a high removal rate of silica (Si), boron (B) and the like through pH control by injecting an alkaline component into the electrochemical treatment process, The amount of chemicals injected for high removal efficiency of silica (Si) and boron (B) is reduced in the reverse osmosis process of the pure treatment section, and as a result, the same amount of alkaline component is added It has the advantage of high removal efficiency.

In addition, the ultra pure water treatment system according to the present invention can be applied to an ultrapure water treatment system in which an effluent treatment process is performed according to characteristics of wastewater, that is, an electrochemical treatment unit, a filtration treatment unit or a mixing treatment unit, This option has the advantage of lowering the total cost.

Fig. 1 is a schematic view showing a process for producing ultrapure water according to the prior art
2 is a block diagram of an ultrapure water treatment system including waste water reuse according to an embodiment of the present invention.
3 is a conceptual diagram of an electrochemical processing unit according to an embodiment of the present invention.

Hereinafter, an ultrapure water treatment system including waste water reuse according to the present invention will be described in detail with reference to the embodiments shown in the drawings.

FIG. 2 is a configuration diagram of an ultrapure water treatment system including waste water reuse according to an embodiment of the present invention, and FIG. 3 is a conceptual diagram of an electrochemical treatment unit according to an embodiment of the present invention.

2 and 3, the ultrapure water treatment system including the reuse of wastewater according to an embodiment of the present invention is a system for producing ultrapure water from raw water and recovering and reusing the used ultrapure water, The pretreatment unit 20, the second storage tank 30, the pure water treatment unit 40, the third storage tank 50, the ultrapure water treatment unit 60, the industrial facility 70, A control unit 80, an electrochemical processing unit 91, a filtering processing unit 92, and a mixing processing unit 93. [

The first storage tank 10 is configured to store raw water to be introduced into the pretreatment unit 20.

In the first storage tank 10 according to an embodiment of the present invention, the ultrapure water wastewater filtered through the filter through the filter processing unit 92 under the control of the reuse control unit 80, The ultrapure water wastewater through the mixing processing unit 93 may be blended with the raw water in the first storage tank 10.

As shown in FIG. 1, the pretreatment unit 20 is configured to pretreat raw water flowing from the first storage tank 10, and a multi-filtration tower, a submerged MF membrane, or the like may be used for pretreatment of raw water.

The second storage tank 30 stores the pretreated water in the pretreatment unit 20.

In the second storage tank 30 according to an embodiment of the present invention, ultrapure wastewater treated through the electrochemical processing unit 91 may be introduced into the second storage tank 30 under the control of the reuse control unit 80.

The pure water treatment unit 40 is configured to treat the treated water flowing from the second storage tank 30 with pure water. As shown in FIG. 1, various apparatuses can be used. In an embodiment of the present invention, Lt; / RTI > process.

Although the final water quality of the ultrapure water production process is determined by the ultrapure water treatment unit 60, the final water quality of the ultrapure water production process differs depending on the quality of the treated water of the pure water treatment unit 40 at the previous stage. In order to operate the stable reverse osmosis process, a proper pretreatment such as the electrochemical treatment unit 91 of the present invention should be designed. The organic relationship of the reverse osmosis treatment and the electrochemical treatment unit 91 will be described later.

The third storage tank 50 stores the pure water processed in the pure water processing unit 40.

Of course, pure water treated in the pure water treatment unit 40 may be directly introduced into the ultrapure water treatment unit 60 without the third storage tank 50.

The ultrapure water processing unit 60 is configured to process pure water that has been processed in the pure water processing unit 40 and stored in the third storage tank 50 to be treated with ultrapure water.

As shown in FIG. 1, the ultrapure water treatment unit 60 may include various apparatuses such as a heat exchanger, an ultraviolet oxidation, an unreproducible anion tower, a non-regenerated mixed-phase ion column, a membrane degasser, and an ultrafiltration membrane.

The industrial facility 70 is a facility for manufacturing semiconductors, medicines, etc. in which ultra pure water processed in the ultrapure water processing unit 60 is used.

As described in the Background Art, ultrapure water is used to wash away impurities on the surface of chemicals and products introduced into the manufacturing process. In the semiconductor manufacturing process, which may cause a great problem of the product performance such as a change in electric conductivity due to impurities, Requires strict water quality.

The reuse control unit 80 controls the reuse control unit 80 such that the ultrapure wastewater is passed through either the electrochemical treatment unit 91, the filtration treatment unit 92, or the mixing treatment unit 93 for reutilization of the ultrapure water wastewater discharged from the industrial facility 70 .

A concrete control method of the reuse control unit 80 according to the characteristics of the ultrapure water wastewater will be described later.

The electrochemical treatment unit 91 is configured to treat ultrapure water discharged from the industrial facility 70 through an electrochemical treatment process and send it to the second storage tank 30.

The electrochemical treatment process utilizes electrical attraction, not chemicals, to efficiently remove contaminants present in the raw water.

The electrochemical treatment process in the electrochemical treatment unit 91 is a process of electrodeposition (a), (b) capacitive deionization, or (c) electrocoagulation Coagulation process.

Since each process for the electrochemical treatment process is a commonly used technique in the industrial field, a detailed explanation is omitted and these processes have been proved to have a high performance of 98% or more at a low energy cost (<0.26 kWh / m ³ , &Lt; 0.1 kWh / m ³ , &Lt; 1.15 kWh / m &lt; ³ &gt;).

When the ultrapure water is passed through the electrochemical treatment unit 91, silica (Si), boron (B) and organic matter (TOC) contained in the ultrapure wastewater are effectively removed.

On the other hand, when the conductivity of the ultrapure water discharged from the industrial facility 70 is less than a predetermined reference value (for example, 1 s / cm), the reuse control unit 80 controls the electrochemical treatment unit 91 .

That is, it is ineffective to pass through the pretreatment unit 20 until the conductivity of the ultrapure water wastewater is less than a set reference value (for example, 1 s / cm) It is possible to reduce the load on the pretreatment unit 20 and ensure the final production water quality by allowing the pretreatment unit 20 to flow directly into the second storage tank 30 through the electrochemical treatment unit 91 It will be possible.

Table 1 below illustrates the characteristics of ultrapure wastewater generated in the semiconductor manufacturing process (Reference: Recovery, Reuse, and Recycle of Water in Semiconductor Wafer Fabrication Facilities, John Degenova (Environmental Progress, Vol. 16, No. 3, 1997).

Water quality
parameter Units Typical ultrapure  물 제품 Segregated  50% spent  rinse water Resistivity M Ohms-cm > 18 0.8 pH units 6 5-7 TOC ppb <10 20 Ammonium ppb <1 300 Calcium ppb <1 68 Magnesium ppb <1 26 Potassium ppb <1 25 Silica ppb <10 338 Sodium ppb <1 237 Chloride ppb <1 100 Fluoride ppb <1 100 Sulfate ppb <1 500

As shown in Table 1, it can be confirmed that silica (Si) is contained in a large amount in the ultrapure wastewater discharged from the industrial facility.

In the reverse osmosis process of the pure water treatment unit 40, organic matter such as silica (Si) and boron (B) contained in the ultrapure wastewater may cause serious problems. The pure water treatment unit 40 The organic material such as silica (Si), boron (B) is efficiently removed from the electrochemical treatment unit 91 before the pure water treatment unit 40 is operated.

Meanwhile, in the electrochemical treatment unit 91 according to an embodiment of the present invention, an alkaline component such as caustic soda is injected into the ultrapure wastewater.

A high removal rate of silica (Si), boron (B), and the like can be achieved owing to the alkali component injected into the electrochemical treatment unit 91. Further, in the reverse osmosis process of the pure water treatment unit 40, , The amount of the chemical to be injected can be reduced for a high removal rate of boron (B), and as a result, a higher removal efficiency can be obtained by the same amount of alkali component.

The filtration processing unit 92 is configured to filter ultrapure wastewater discharged from the industrial facility 70 through a filter and to be sent to the first storage tank 10 to be blended with raw water.

The reuse control unit 80 may be configured to control the reuse control unit 80 such that the conductivity of the ultrapure wastewater discharged from the industrial facility 70 is equal to or greater than a predetermined reference value (for example, 1 s / cm) (5000 mg / L, for example), the ultrapure wastewater is controlled to pass through the filtration processing unit 92.

That is, for wastewater having TS or SS, which is contaminated rather than the high purity ultrapure wastewater which can be treated by the electrochemical treatment unit 91, and whose solids amount per unit volume is set to a reference value (for example, 5000 mg / L) 1 storage tank 10 to be blended with raw water through a primary pretreatment through a filter rather than being blended with raw water, and then to be processed by the pretreatment unit 20.

This is because, if the wastewater containing a high pollutant source as described above is directly sent to the pretreatment unit 20 without being filtered, the pretreatment unit 20 may be overloaded and adversely affected.

The mixing treatment unit 93 is configured to directly feed ultrapure water discharged from the industrial facility 70 to the first storage tank 10 to blend the raw water with raw water.

The reuse control unit 80 may be configured to control the reuse control unit 80 such that the conductivity of the ultrapure wastewater discharged from the industrial facility 70 is equal to or greater than a predetermined reference value (for example, 1 s / cm) (5000 mg / L, for example), it controls the ultrapure wastewater to pass through the mixing processing unit 92.

That is, wastewater having a level equal to that of a surface water having a level of solid matter per unit volume equal to or less than a predetermined reference value (for example, 5000 mg / L) is polluted rather than the high purity ultrapure wastewater that can be treated by the electrochemical treatment unit 91, This is because it is preferable to blend the raw water with the raw water in the first storage tank 10 and process it in the pre-treatment unit 10.

The present invention is based on the organic coupling relationship between the electrochemical treatment unit 91, the filtration treatment unit 92, the mixing treatment unit 93, and the reuse control unit 80, and according to the characteristics of the ultrapure wastewater discharged from the production facility, The process can be carried out, that is, an efficient method for removing major pollutants can be selectively applied, thereby lowering the total cost.

The ultrapure water treatment system including the wastewater recycling described above and shown in the drawings is only one embodiment for practicing the present invention and should not be construed as limiting the technical idea of the present invention. The scope of protection of the present invention is defined only by the matters set forth in the following claims, and the embodiments improved and changed without departing from the gist of the present invention are obvious to those having ordinary skill in the art to which the present invention belongs It will be understood that the invention is not limited thereto.

10 First Storage Tank 20 Pretreatment Unit
30 Second storage tank 40 Pure water treatment section
50 Third storage tank 60 Ultrapure water treatment section
70 Industrial facility 80 Reuse control unit
91 electrochemical treatment part 92 filtration treatment part
93 Mix processing section

Claims (7)

A first storage tank in which raw water is stored;
A pretreatment unit for pretreating the raw water introduced from the first storage tank;
A second storage tank for storing the pretreated water in the pretreatment unit;
A pure water treatment unit for treating the treated water flowing from the second storage tank with pure water;
An ultrapure water treatment unit for treating the pure water treated in the pure water treatment unit with ultrapure water;
An industrial facility in which ultra pure water treated in the ultra pure water processing unit is used;
An electrochemical treatment unit for treating ultrapure water discharged from the industrial facility through an electrochemical treatment process and sending it to the second storage tank;
A filtration unit for filtering ultrapure wastewater discharged from the industrial facility through a filter to be sent to the first storage tank to blend with raw water;
A mixing treatment unit for directly feeding ultrapure wastewater discharged from the industrial facility to the first storage tank and blending the wastewater with raw water;
A reuse control unit for controlling ultrapure water discharged from the industrial facility to pass through either the electrochemical treatment unit, the filtration treatment unit or the mixing treatment unit; Wherein the ultrapure water treatment system comprises:
The method according to claim 1,
Wherein the electrochemical treatment process in the electrochemical treatment unit is an electrodeposition process, a capacitive deionization process, or an electrocoagulation process.
The method according to claim 1,
Wherein the pure water treatment section includes a reverse osmosis process.
The method of claim 3,
Wherein the electrochemical treatment unit injects an alkaline component into the ultrapure water wastewater.
delete The method according to claim 1,
Wherein the reuse control unit controls the ultrapure water wastewater to pass through the electrochemical processing unit when the conductivity of the ultrapure wastewater discharged from the industrial facility is less than a set reference value.
The method according to claim 6,
Wherein the reuse control unit controls the conductivity of the ultrapure wastewater discharged from the industrial facility to be equal to or greater than a predetermined reference value and controls the ultrapure wastewater to pass through the filtration processing unit when the amount of solids per unit volume is equal to or greater than a set reference value. And an ultrapure water treatment system.

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