KR101644275B1 - Electrolysis device and water treatment method using the device - Google Patents

Abstract

The present invention relates to an electrolysis device and a water treatment method using the same. More specifically, provided is an electrolysis device which includes: a sealed electrolyzer; a positive electrode plate installed in the electrolyzer; a negative electrode plate installed in the electrolyzer while being separated from the positive electrode plate; and a barrier installed between the positive electrode plate and the negative electrode plate. According to the present invention, the electrolysis device can increase water treatment efficiency and prevents corrosion and odor production.

Description

[0001] Electrolysis apparatus and water treatment method using the same [0002]

The present invention relates to an electrolytic apparatus and a water treatment method using the electrolytic apparatus.

As shown in FIG. 1, oil wastewater from the nuclear power plant is divided into oil wastewater and chemical wastewater. The oil wastewater concentrated through the advanced oil separator is treated separately, Water enters the chemical waste water tank. In addition to the treated water through the oil separator, the chemical wastewater tank is also equipped with a Cation exchange resin (CPP) for the steam generator blowdown (SGBD) wastewater and a second system water cooling water reactor (CPP: Condensate polishing plant) ) Wastewater generated in the regeneration process is collected and stored.

During regeneration of the CPP cation exchange resin using sulfuric acid (H ₂ SO ₄ ), ethanolamine (ETA: Ethanolamine, HOCH ₂ CH ₂ NH ₂ ) contained in the secondary system cooling water is bound to the cation exchange resin , And hydrogen ions (H ⁺ ) and contained in the CPP cation exchange resin regeneration wastewater.

[Reaction Scheme 1]

(1) ethanolamine cationization

HOCH ₂ CH ₂ NH ₂ + H ₂ O ↔ HOCH ₂ CH ₂ NH ₃ ⁺ + OH ^-

(2) Ethanolamine bonding to the cation exchange resin

Cation resin-H ₂ + 2HOCH ₂ CH ₂ NH ₃ ⁺ → Cation resin- (HOCH ₂ CH ₂ NH ₃ ⁺ ) ₂ + 2H ⁺

(3) Ethanolamine desorption from cation exchange resin

_{Cation resin- (HOCH 2 CH 2 NH} 3 +) 2 + H 2 SO 4 → Cation resin-H 2 + 2HOCH 2 CH 2 NH 3 + + SO 4 2 -

ETA has been used since 2001 as a substitute for ammonia (NH ₃ ), which has been used as a pH regulator for secondary system cooling water in domestic nuclear power plants. However, since ETA is a refractory organic material containing nitrogen (N: Nitrogen) in the environmental aspect, it is very difficult to remove it from the wastewater treatment facility, thereby increasing the COD and TN concentration of the effluent.

Conventional wastewater treatment plants treated chemical wastewater by coagulation, sedimentation, filtration and adsorption. However, the wastewater treatment facilities in the water quality environment conservation law of Table 1, which are strengthened step by step from January 1, 2008 to January 1, 2013, (EDR) for the production of reusable water since the mid 2000s with the aim of reusing water while reducing the COD and TN concentration generated by the refractory ETA to below the effluent water quality standard, dialysis reversal device and an electrochemical decomposing system (ECDS) for treating ETA-containing concentrated water generated by EDR.

division Application period and water quality standard Until 31st December 2007 From January 1, 2008
Until 31 December 2012 Since 2013.01.01 Biological oxygen demand (BOD) (mg / L) 30 or less 20 or less below 10 Chemical oxygen demand (COD) (mg / L) 40 or less 40 or less 40 or less Amount of Suspended Substance (SS) (mg / L) 30 or less 20 or less below 10 Total nitrogen (T-N) (mg / L) 60 or less 40 or less 20 or less Total phosphorus (T-P) (mg / L) 8 or less 4 or less 2 or less Total coliforms (total coliforms / mL) - 3,000 or less 3,000 or less

However, even with the ECDS currently installed, it is difficult to treat EDR concentrated water containing ETA at a level lower than the water quality standard prescribed by the Water Quality Conservation Act, and odor generation and corrosion around the apparatus are caused during operation. Therefore, there is a need for an optimal treatment method of decomposing ETA in EDR concentrated water to satisfy the water quality standards of COD and T-N concentrations.

Electrochemical methods for treating contaminants (organic substances) in wastewater are classified into electrolysis, electro-coagulation, and electro-flotation. As shown in FIG. 2, Direct anodic oxidation is used to directly remove contaminants from the anode, and indirect oxidation is used to remove contaminants from the anode and cathode using an oxidizing agent. In the case of direct anodization, hydroxide ions (OH ^- ) generated by electrolysis of water are adsorbed on the surface of the anode and converted into hydroxyl radicals (HO)) by electron exchange with the anode to directly decompose the contaminants. In the case of indirect oxidation, the chloride ion (Cl ^- ) in the aqueous solution is converted into the chlorine molecule (Cl ₂ ) and the hypochlorous acid (Cl -) generated by the electrolysis of the dissolved dissolved chlorine (Dissolved Cl ₂ ) HOCl) and hypochlorite ion (OCl ^- ) decompose contaminants.

[Reaction Scheme 2]

(1) Anode reaction

2Cl ^- ? Cl ₂ (dissolution) + 2e ^-

Anode surface [HO] + Cl ^- → Anode surface [HOCl] + e ^-

(2) Cathode reaction

2H ₂ O + 2e ^- ? H ₂ + 2OH ^-

(3) Reaction between electrodes

Cl ₂ (dissolved) + H ₂ O → HOCl + Cl ^- + H ⁺

^{HOCl + OH - → OCl - +} H 2 O

ETA is first decomposed into acetic acid (CH ₃ COOH) and ammonia (NH ₃ ) and then decomposed into carbon dioxide (CO ₂ ), water (H ₂ O) and nitrogen (N ₂ ) again. Therefore, compounds that affect the COD of wastewater are mainly ETA, CH ₃ COOH and derivatives thereof. Compounds that affect TN are mainly ETA, NH ₃ , NO ₃ ^- and their derivatives.

As shown in FIG. 4, decomposition of ETA, which is an organic substance containing nitrogen, finally results in CO ₂ , H ₂ O, and H ₂ O, which are generated from the hydroxide radicals (HO 揃) electrochemically generated at the anode surface and HOCl and OCl ^- N ₂ , COD and TN can be reduced to below the discharged water quality standard.

Generally, the electrochemical treatment apparatus has a shape and structure for treating wastewater by installing an electrode in an open water tank and then attaching a lid to the upper part of the water tank. However, if the airtightness between the water tank top and the lid is not perfect, Chlorine (Cl ₂ ) and ozone (O ₃ ) diffuse out of the apparatus, causing odor, corrosion of the apparatus and human body effect.

An object of the present invention is to provide an electrolytic apparatus capable of improving water treatment performance of wastewater and preventing odor generation and apparatus corrosion, and a water treatment method using the electrolytic apparatus.

In order to achieve the above object, the present invention provides a sealed electrolytic bath; A positive electrode plate installed in an electrolytic cell; A negative electrode plate disposed apart from the positive electrode plate in the electrolytic cell; And a diaphragm provided between the positive electrode plate and the negative electrode plate.

According to one embodiment of the present invention, the diaphragm may have a resistance of at least 1 M? Measured when wetted with distilled water.

According to another embodiment of the present invention, the diaphragm has a resistance of less than 1 M? Measured when wetted with distilled water, and an insulator may be provided between the diaphragm and the positive electrode plate and between the diaphragm and the negative electrode plate.

An electrolytic apparatus according to the present invention includes: a supply water inlet provided on one of a cathode plate and a cathode plate; A treated water outlet provided on the other of the positive electrode plate and the negative electrode plate; A connection pipe connecting the feed water inlet and the process water outlet may be further included.

The electrolytic apparatus according to the present invention may further include a gas-liquid separator installed in the connection pipe.

According to one embodiment of the present invention, the supply water inlet is provided on the anode plate side, the process water outlet is provided on the cathode plate side, and the connection pipe can supply the cathode water treated on the cathode plate side to the anode plate side.

According to another embodiment of the present invention, the supply water inlet is provided on the positive electrode plate side, the treated water discharge port is provided on the negative electrode plate side, and the connection pipe can supply the anodized water treated on the positive electrode plate side to the negative electrode plate side.

In the present invention, the positive electrode plate and the negative electrode plate are provided in the form of electrode modules, and n bipolar electrodes and n + 1 diaphragms are provided between the positive and negative electrode plates, and n may be an integer of 1 or more.

The electrolytic apparatus according to the present invention can be used for water treatment, and in particular, can be used for treatment of effluent wastewater from a power plant.

Further, the present invention provides a water treatment method using the above-described electrolytic apparatus.

In the water treatment method according to the present invention, the initial pH of the feed water supplied to the electrolytic apparatus may be 6 or less or 9 or more.

The electrolytic apparatus according to the present invention has a sealed structure using a diaphragm and a connection pipe, thereby improving the water treatment efficiency and preventing odor generation and corrosion induction.

1 schematically shows a process flow diagram of a power plant wastewater treatment process according to the prior art.
Fig. 2 schematically shows the principle of organic matter oxidation by electrolysis.
Figure 3 schematically illustrates the degradation pathway and end product of ethanolamine (ETA).
FIG. 4 schematically shows the mechanism of the decomposition reaction of oxidizing agent and organic matter by electrolysis.
FIG. 5 shows a closed-type modular electrolytic apparatus according to an embodiment of the present invention.
Fig. 6 shows a state of an open type container (electrolytic cell type) electrolysis test apparatus according to Comparative Example 1. Fig.
Fig. 7 schematically shows a single-pole electrolyzer-type electrolytic apparatus according to one embodiment of the present invention.
Fig. 8 schematically shows a biodegradable electrolytic apparatus according to another embodiment of the present invention.
Figure 9 shows the electrochemical oxidation potential (EOP) of the oxidant components.
FIG. 10 shows the water treatment flow in the electrolytic apparatus equipped with the diaphragm according to the present invention and the organic decomposition species present in the electrolytic bath.
Figure 11 shows pH conditions effective for water treatment.
12 shows a continuous water treatment system according to an embodiment of the present invention.
13 shows a semi-continuous water treatment system according to another embodiment of the present invention.
Fig. 14 schematically shows an electrolytic apparatus of Comparative Example 2. Fig.
15 schematically shows an electrolytic apparatus of Comparative Example 3. Fig.
16 schematically shows an electrolytic apparatus of Comparative Example 4. Fig.
17 is a graph showing COD changes with time in Example 2. Fig.
18 is a graph showing COD change with time in Comparative Example 2. Fig.
FIG. 19 is a graph showing pH change with time in Example 2. FIG.
20 is a graph showing the pH change of Comparative Example 2 with time.
21 is a graph showing a voltage change with time in the second embodiment.
FIG. 22 is a graph showing a change in voltage with time in Comparative Example 2. FIG.
23 is a graph showing COD change with time in Comparative Example 3. Fig.
24 is a graph showing the pH change of Comparative Example 3 with time.
25 is a graph showing a change in voltage with time in Comparative Example 3. Fig.
26 is a graph showing COD change with time in Comparative Example 4. FIG.
FIG. 27 is a graph showing the pH change of Comparative Example 4 with time. FIG.
28 is a graph showing a change in voltage with time in Comparative Example 4. Fig.
FIG. 29 is a graph showing COD change with time in Example 3. FIG.
30 is a graph showing the pH change with time in Example 3. Fig.
31 is a graph showing a change in voltage with time in the third embodiment.
32 is a graph showing changes in COD with time in Example 4. FIG.
33 is a graph showing the pH change with time in Example 4. Fig.
34 is a graph showing a voltage change with time in the fourth embodiment.
35 is a graph showing COD and TN changes over time at CPP regeneration wastewater pH 3.6 of Example 5. Fig.
36 is a graph showing changes in COD and TN with time in the CPP regeneration wastewater pH 10.3 of Example 5. Fig.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 7 schematically shows an electrolytic apparatus in the form of a monopolar electrolytic tank according to an embodiment of the present invention. The electrolytic apparatus according to the present invention may include an electrolytic bath, a cathode plate, a cathode plate, and a diaphragm.

The electrolytic cell is preferably a closed electrolytic cell. When the electrolytic cell is of a hermetically sealed type, the internal pressure of the electrolytic cell slightly rises and the chlorine gas (Cl ₂ gas) generated from the sodium chloride can dissolve more in the aqueous solution and the hypochlorous acid which indirectly oxidizes the organic matter from the dissolved chlorine gas acid, HOCl) and hypochlorite ion (hypochlorite ion, OCl ^- so) can be much more generated, the processing efficiency can be improved. In addition, when the electrolytic cell is formed in a hermetically sealed structure, gases such as chlorine and ozone can be prevented from being discharged to the outside, thereby solving the problem of odor and corrosion. That is, the closed type electrolytic cell is effective in improving the treatment efficiency and preventing odor generation and corrosive gas discharge. The electrolytic bath is preferably made of a material resistant to corrosion by chlorine ions or the like. One or more electrolytic cells may be provided.

As described above, when the electrode is provided in the closed electrolytic cell and then water treatment is performed, the solubility of the chlorine gas is increased to generate more HOCl and OCl ^- , thereby improving the treatment efficiency of indirect oxidation of the organic substance. So that the life of the device can be extended while maintaining a comfortable working environment.

The positive electrode plate and the negative electrode plate are provided inside the electrolytic cell and are spaced apart from each other at regular intervals. An insoluble catalyst electrode is used for the positive electrode plate and a general electrode which is resistant to corrosion can be used as the negative electrode plate to convert the organic matter present in the water into carbon dioxide, water, nitrogen and the like through the electrochemical redox reaction. The positive electrode plate is insoluble, and the negative electrode plate is preferably made of a material resistant to corrosion. The higher the current density of the electrode, the greater the processing efficiency. The electrode area (contact area) can be associated with the current density and affect the process efficiency. The smaller the electrode spacing, the greater the processing efficiency and can generally be within 3 cm. The positive electrode plate and the negative electrode plate may be installed in the form of an electrode module.

The diaphragm may be installed between the positive electrode plate and the negative electrode plate. An anode chamber may be formed on the (+) electrode side with respect to the diaphragm, and a cathode chamber may be formed on the (-) electrode side. In the present invention, water treatment efficiency can be improved by using a diaphragm.

It is preferable that the diaphragm has at least one physical property such as durability so as not to deteriorate under the harsh conditions such as insulation and nuclear wastewater, and porosity so that ions move smoothly so that electricity does not pass therethrough. In particular, it is preferable that the diaphragm has both insulation property, durability and porosity .

In order to secure insulation, a diaphragm having a high resistance can be used, and in this case, the resistance can be 1 M? Or more. At this time, the resistance may be a resistance measured when the diaphragm is wetted with distilled water. The resistance measurement can be performed using a resistance meter, a multimeter, or the like. In this case, the upper limit value of the resistance may be, for example, 100 MΩ. As the diaphragm corresponding to this, most of the fiber membranes are exemplified.

A diaphragm with a resistance of less than 1 MΩ may also be used, in which case an insulator must be provided between the diaphragm and the positive plate and between the diaphragm and the negative plate. In this case, the lower limit of the resistance may be, for example, 1 OMEGA. Examples of the diaphragm include an ion exchange resin membrane (resistance of about 30 Ω), a carbon material, or a fibrous film coated or deposited with a metal material.

In order to ensure durability, diaphragm made of fluororesin (PTFE, Teflon), inorganic material such as ceramics, or fibrous film coated or deposited with a metal material can be used.

In order to ensure porosity, for example, a diaphragm having a pore size of 0.1 to 0.5 탆 may be used.

As the diaphragm, an anion exchange resin membrane may also be used. When an anion exchange resin membrane is used, hydroxide ions (OH <"& gt ^; ) which react with chlorine gas generated in the anode to generate hypochlorous acid (HOCl) are moved from the cathode to the anode to increase decomposition of organic matter in the anode chamber, Calcium ions (Ca ^{2 +} ) and magnesium ions (Mg ^{2 +} ) forming scales on the cathode can not be moved to the cathode, thereby preventing scale formation on the anode plate.

The diaphragm material is preferably made of a material having high acid resistance, chemical resistance and high strength. The fibrous membrane and the anion exchange resin membrane can be made of a nonconductive polymer.

An electrolytic apparatus according to the present invention includes: a supply water inlet provided on one of a cathode plate and a cathode plate; A treated water outlet provided on the other of the positive electrode plate and the negative electrode plate; And a connection pipe connecting the feed water inlet and the process water outlet.

According to one embodiment of the present invention, the supply water inlet is provided on the anode plate side, the process water outlet is provided on the cathode plate side, and the connection pipe can supply the cathode water treated on the cathode plate side to the anode plate side.

According to another embodiment of the present invention, the supply water inlet is provided on the positive electrode plate side, the treated water discharge port is provided on the negative electrode plate side, and the connection pipe can supply the anodized water treated on the positive electrode plate side to the negative electrode plate side.

According to a preferred embodiment of the present invention, the supply water inlet is provided on the cathode plate side, the treated water outlet is provided on the cathode plate side, the connection tube is treated on the cathode plate side (cathode chamber) By supplying the cathode treated water containing a large amount of hydroxide ions (OH < ^- & gt ^; ) to the anode plate side (anode chamber), secondary treatment can be performed directly by oxidation and indirect oxidation at the anode. The movement of the treated water can be performed through a pump or the like.

The electrolytic apparatus according to the present invention may include a gas-liquid separator installed in a connection pipe, and the connection pipe may include a gas outlet, a pump, and the like. After separation of the hydrogen (H ₂ ) gas generated in the cathode from the cathode-treated water using a gas-liquid separator such as a cyclone, the separated hydrogen gas is discharged through the gas discharge port to smoothly transport the cathode- And it is also possible to prevent the electrolysis efficiency by the hydrogen gas from being reduced in the anode plate side (anode chamber).

8 schematically shows a biodegradable electrolytic apparatus according to another embodiment of the present invention. Bipolar electrodes may be provided between a positive electrode plate and a negative electrode plate. At this time, n may be an integer of 1 or more. When n number of double electrodes are provided, n + 1 diaphragms may be provided. The diaphragm is installed between the positive electrodes, and therefore one more than the number of negative electrodes can be provided. In the case where a double electrode is installed, the supply water inlet, the process water outlet, and the connection pipe may each have a plurality of branch pipes. In the case of a bi-polar electrolytic cell, the treatment efficiency may be similar or high at the same current applied to the single-pole electrolytic cell, resulting in an economical effect in terms of energy consumption.

The electrolytic apparatus according to the present invention can be used for water treatment, particularly for all wastewater treatment containing organic matter, preferably for power plant wastewater treatment, more preferably for ETA-containing nuclear wastewater treatment have.

Further, the present invention provides a water treatment method using the above-described electrolytic apparatus.

Preferably, supply water (wastewater or the like) is supplied to the negative electrode plate side, and the negative electrode treatment water treated on the negative electrode plate side is supplied to the positive electrode plate through the connection pipe. That is, it is preferable to treat the negative electrode first and then the positive electrode. As described above, the anodic treatment after the cathode treatment has a higher water treatment efficiency (particularly, the decomposition efficiency of the organic matter) compared with the case where the cathode treatment is performed after the anode treatment.

In the present invention, by using the diaphragm and performing the anode treatment after the cathode treatment, the organic substance decomposition efficiency is high and the operation voltage (current) is low, which is efficient.

9 shows the electrochemical oxidation potential (EOP) of the oxidizing agent components. Hydroxyl radical (HO) and ozone (O ₃ ) are higher than hyperchlorite (OCl ^- ) With high electrochemical oxidation potential, direct oxidation at the anode is effective for decomposition of organic matter.

10 shows the decomposition species of organic substances present in the water treatment flow and the electrolytic cell in the electrolytic apparatus equipped with the diaphragm according to the present invention. First, the organic matter is decomposed by OCl ^- generated from the cathode plate side, (OH ^- ) is supplied to the cathode plate through the connection pipe, and is combined with chlorine (Cl ₂ ) at the cathode plate side to generate HOCl to decompose the organic matter. Further, the organic substance is further directly decomposed (oxidized) by the hydroxyl radical (HO) on the surface of the anode. Since the oxidizing agent may remain in the anodic treatment water, a retention tank may be provided at the rear end of the electrolysis apparatus or circulated to the supply water storage tank at the front end of the electrolysis apparatus to increase the treatment efficiency.

On the other hand, when the diaphragm is a fibrous membrane, the feed water can be supplied to the cathode plate side.

When the diaphragm is an anion exchange resin membrane, supply water may be supplied to the positive electrode plate side and sodium chloride (NaCl) aqueous solution may be supplied to the negative electrode plate side. When an anion exchange resin membrane is used, Ca ²⁺ , Mg ^{2 +,} etc. can not move toward the cathode plate, so that scale can be prevented.

In addition, Ca ^{2 +} and Mg ^{2 +} components can be removed prior to water treatment to remove scale as a pretreatment. In addition, as a post-treatment, chlorine and ozone generation during water treatment can be controlled to eliminate corrosion and odor.

Fig. 11 shows a water treatment pH condition. The initial pH of the feed water supplied to the electrolytic apparatus may be 6 or less or 9 or more. The organic degradation efficiency is highest in acidic conditions (pH 3 to 6), the next highest in alkaline conditions (pH 9 to 11), and lowest in neutral conditions. If the initial pH of the feed water is out of the range, adjusting the pH using an acid or base may be performed.

12 shows a water treatment system according to an embodiment of the present invention in which the electrolytic apparatus is connected to the feed water reservoir toward the feed water inlet and can be connected to the retention reactor toward the treated water outlet, . This method is suitable for the treatment of nuclear wastewater containing low concentration (0.2 wt% or less) of ETA.

13 shows a water treatment system according to another embodiment of the present invention in which the electrolytic device is connected to the feed water reservoir toward the feed water inlet port and to the same feed water reservoir for the process water outlet port, It can be water-treated in a circulating manner. At this time, the smaller the circulation flow rate, the higher the treatment efficiency. This method is suitable for treating nuclear wastewater containing ETA at high concentration (more than 0.3 wt%).

The water treatment system according to still another embodiment of the present invention further uses a reused water production device selected from a reverse electrodialysis device (EDR) and a reverse osmosis treatment device (RO), and the concentrated water from the reused water production device is electrolyzed The device can be processed. The EDR and / or RO device may be installed upstream of the electrolytic device. The clean production water treated in the EDR and / or RO unit can be reused as industrial water, and the concentrated water from the EDR and / or RO unit can be treated again in the electrolysis apparatus according to the present invention. By using the EDR and / or the RO apparatus and the electrolytic apparatus according to the present invention in combination, it is possible to efficiently and stably treat the wastewater containing the poorly decomposable ETA which is the pH regulator of the secondary system cooling water of the power plant.

Hereinafter, the present invention will be described more specifically by way of examples.

[Example 1]

As shown in Fig. 5, CPP regeneration wastewater generated from a nuclear power plant was treated using a closed-type modular electrolytic cell.

[Comparative Example 1]

As shown in Fig. 6, CPP regeneration wastewater generated from a nuclear power plant was treated with an open-type vessel (tank) type electrolytic cell.

[Example 2]

As shown in FIG. 7, a diaphragm (fiber membrane) was provided between the two electrode plates, and simulated wastewater containing 0.05% ETA (low concentration) was injected into the cathode plate side. Then, the cathode treated water was supplied to the cathode plate side through the connecting pipe, And the treated water was discharged from the side.

[Comparative Example 2]

As shown in FIG. 14, a diaphragm (fibrous membrane) was provided between two electrode plates, and simulated wastewater containing 0.05% ETA was injected into the cathode plate side, and an anode treated water was supplied to the cathode plate side through a connecting pipe. Respectively.

[Comparative Example 3]

As shown in FIG. 15, the diaphragm was not provided between the two electrode plates, and simulated wastewater containing 0.05% ETA was injected into the cathode plate side, then the cathode treated water was supplied through the connecting pipe to the cathode plate side, Respectively.

[Comparative Example 4]

As shown in FIG. 16, a diaphragm (fiber membrane) was provided between the two electrode plates, and no connection pipe was provided. Simulated wastewater containing 0.05% ETA was injected into the anode plate side and then treated water was discharged from the anode plate side.

[Example 3]

As shown in FIG. 7, a diaphragm (fiber membrane) was provided between the two electrode plates, and simulated wastewater containing 0.5% ETA (high concentration) was injected into the cathode plate side. Then, the cathode treated water was supplied to the cathode plate side through the connecting pipe, And the treated water was discharged from the side.

[Example 4]

As shown in FIG. 8, a bipolar membrane and a diaphragm (fiber membrane) were installed between two electrode plates, and simulated wastewater containing 0.05% ETA was injected into the cathode plate side, , And the treated water was discharged from the bipolar plate side.

[Example 5]

As shown in FIG. 7, a diaphragm (fiber membrane) was provided between the two electrode plates, CPP cation exchange resin regenerated wastewater generated in the nuclear power plant was injected into the cathode plate side, and then the cathode treated water was supplied to the cathode plate side through the connection tube. The treated water was discharged.

[Test Example]

Using the modular electrolytic cell of Example 1 and the container type electrolytic cell of Comparative Example 1, COD and T-N changes of CPP regeneration wastewater generated from a nuclear power plant over time were measured. COD was measured using a COD analyzer, and T-N was measured using a T-N analyzer.

Table 2 summarizes the changes in COD and TN concentrations in Example 1 and Comparative Example 1. It was found that the results of treatment using an enclosed modular electrolytic cell were excellent, It is effective to decompose organic matter including nitrogen.

time
(hr) CPP regeneration wastewater Example 1 (closed type modular type) Comparative Example 1 (open container type) COD _Mn (ppm) T-N (ppm) COD _Mn (ppm) T-N (ppm) 0.0 660 710 660 710 1.5 567 381 584 475

For Examples 2 to 4 and Comparative Examples 2 to 4, COD, pH, and voltage change with time were measured using simulated wastewater. COD was measured using a COD analyzer, pH was measured using a pH meter, and voltage was recorded at the voltage applied to the rectifier.

17 to 22 show comparative evaluation of the treatment performance according to the pH of the wastewater and the electrode treatment sequence.

FIG. 17 is a graph showing COD change with time in Example 2, FIG. 18 is a graph showing COD change with time in Comparative Example 2, and FIG. 18 is a graph showing changes in COD in Example 2 in all pH ranges of wastewater, Can be confirmed.

FIG. 19 is a graph showing pH change with time in Example 2, FIG. 20 is a graph showing pH change with time in Comparative Example 2, and pH in Example 2 is the environmental emission standard 6 to 8, and in the case of Comparative Example 2, the environmental emission standards were largely deviated.

FIG. 21 is a graph showing the voltage change with time in Example 2, FIG. 22 is a graph showing a voltage change with time in Comparative Example 2, wherein the voltage in Example 2 is higher than that in Comparative Example 2 Low.

17, 19, 21 and 23 to 25 are comparative evaluations of the treatment performance depending on the presence or absence of the diaphragm in the electrolytic bath.

FIG. 23 is a graph showing COD change over time in Comparative Example 3, and it can be seen that the COD reduction rate of Example 2 is higher than that of Comparative Example 3 in all the pH ranges of wastewater when comparing FIGS. 17 and 23.

FIG. 24 is a graph showing pH change with time in Comparative Example 3, wherein the final pH of Comparative Example 3 was similar to that of Example 2 when comparing FIGS. 19 and 24.

FIG. 25 is a graph showing the voltage change with time in Comparative Example 3, wherein the voltage of Comparative Example 3 was slightly lower than that of Example 2.

Figs. 17, 19, 21 and Figs. 26 to 28 are comparative evaluations of the treatment performance depending on the presence or absence of the connection pipe between the cathode chamber and the anode chamber.

FIG. 26 is a graph showing COD change over time in Comparative Example 4, and it can be confirmed that the COD reduction rate in Example 2 is higher than that in Comparative Example 4 in comparison between FIG. 17 and FIG.

FIG. 27 is a graph showing the pH change of Comparative Example 4 with time. When comparing FIG. 19 and FIG. 27, the final pH of Comparative Example 4 was similar to that of Example 2.

FIG. 28 is a graph showing a change in voltage with time in Comparative Example 4, wherein the voltage in Example 2 was lower than that in Comparative Example 4.

17, 19, 21 and 29 to 31 are comparative evaluations of treatment performance of wastewater of low concentration and high concentration. The higher the ETA concentration, the higher the current density or the longer the treatment time.

FIG. 29 is a graph showing COD change with time in Example 3, wherein the amount of COD reduction in Example 3 was larger than that in Example 2 when comparing FIGS. 17 and 29.

Table 3 compares the amounts of decrease in COD concentration in Examples 2 and 3, and shows the same results as in Figs. 17 and 29.

time
(hr) Example 2 (low concentration, 0.05% ETA) Example 3 (high concentration, 0.5% ETA) pH 4.8 pH 10.8 pH 4.6 pH 10.4 density
(ppm) density
decrease
(ppm) density
(ppm) density
decrease
(ppm) density
(ppm) density
decrease
(ppm) density
(ppm) density
decrease
(ppm) 0.0 464 - 464 - 4285 - 4285 - 0.5 165 299 148 316 3865 420 3855 430 1.0 96 368 79 385 3615 670 3740 545 1.5 6 458 65 399 3610 675 3380 905

FIG. 30 is a graph showing the pH change with time in Example 3, and when comparing FIGS. 19 and 30, the pH of Example 2 satisfies the environmental emission standard in all pH ranges of the wastewater, and in the case of Example 3 Exceeded environmental emission standards.

FIG. 31 is a graph showing the voltage change with time in the third embodiment. When comparing FIG. 21 and FIG. 31, the voltage in the third embodiment is similar to that in the second embodiment.

Figs. 17, 19, 21 and Figs. 32 to 34 show comparative evaluation results of the processing performance of the unipolar electrolytic cell and the bi-polar electrolytic bath.

FIG. 32 is a graph showing changes in COD with time in Example 4, wherein the COD reduction amount in Example 4 was slightly smaller than that in Example 2 when comparing FIGS. 17 and 32, , Respectively.

Table 4 compares the amounts of decrease in COD concentration in Examples 2 and 4, and shows the same results as in Figs. 17 and 32. Fig.

time
(hr) Example 2 (Single-pole electrolytic bath) Example 4 (Double electrode electrolytic bath) Low concentration (0.05% ETA), pH 10.8 Low concentration (0.05% ETA), pH 10.6 Concentration (ppm) Concentration Reduction (ppm) Concentration (ppm) Concentration Reduction (ppm) 0.0 464 - 453 - 0.5 148 316 223 230 1.0 79 385 143 310

FIG. 33 is a graph showing changes in pH with time in Example 4, wherein the pH of Example 2 satisfies the environmental emission standard in all the pH ranges of the wastewater when comparing FIG. 19 and FIG. 33, Also in the case of Example 4, the environmental emission standards were satisfied.

FIG. 34 is a graph showing a voltage change with time in Example 4, wherein the voltage between the two electrodes in Example 4 is high when comparing FIGS. 21 and 34, but the distance between the electrodes is 1 cm in the unipolar electrolyzer The results were similar to those of Example 2.

For Example 5, the initial pH of the wastewater was adjusted to 3.6 and 10.3, respectively, using the test wastewater generated from the nuclear power plant, and the COD and T-N changes with time were measured. COD was measured using a COD analyzer, and T-N was measured using a T-N analyzer.

35 is a graph showing changes in COD and TN with time for the initial pH 3.6 of the wastewater of Example 5. The COD and TN concentrations of the treated water are shown in Table 1 as the discharged water quality standards of the wastewater treatment facility Satisfied or similar level.

36 is a graph showing changes in COD and TN with time for the initial pH 10.3 of the wastewater of Example 5. The COD and TN concentrations of the treated water are shown in Table 1 as the discharged water quality standards of the wastewater treatment facility Satisfied or similar level.

Table 5 summarizes the COD and T-N concentration changes in Example 5, and shows the same results as Figs. 35 and 36.

time
(hr) CPP regeneration wastewater pH 3.6 pH 10.3 COD _Mn (ppm) T-N (ppm) COD _Mn (ppm) T-N (ppm) 0.0 632 730 460 680 0.5 81 402 272 336 1.0 71 222 275 218 1.5 135 43 264 89 2.0 17 22 17 29

From the above experimental results, it was confirmed that the diaphragm was used and the anodic treatment was efficient after the cathodic treatment as in the present invention, and it was confirmed that the treatment was also possible using the biocide.

Claims (11)

Sealed electrolytic cell;
A positive electrode plate installed in an electrolytic cell;
A negative electrode plate disposed apart from the positive electrode plate in the electrolytic cell;
A diaphragm provided between the positive electrode plate and the negative electrode plate;
A supply water inlet provided on the cathode plate side;
A treated water outlet provided on the positive electrode plate side;
And a connection pipe for supplying the cathode treated water treated on the cathode plate side to the cathode plate side.
The method according to claim 1,
Wherein the diaphragm has a resistance of 1 M? Or more measured when wetted with distilled water. The electrolytic apparatus for treating wastewater of nuclear power plants containing ethanolamine.
The method according to claim 1,
Characterized in that the diaphragm has a resistance of less than 1 M OMEGA when wetted with distilled water and that an insulator is provided between the diaphragm and the positive electrode plate and between the diaphragm and the negative electrode plate.
delete The method according to claim 1,
Further comprising a gas-liquid separating device installed in the connecting pipe, wherein the electrolytic decomposing device comprises an ethanolamine.
delete The method according to claim 1,
Wherein the positive electrode plate and the negative electrode plate are installed in the form of electrode modules, n positive electrodes and n + 1 diaphragms are provided between the positive electrode plate and the negative electrode plate, and n is an integer of 1 or more. Decomposition device.
delete delete An electrolytic apparatus according to claim 1,
Treating the supply water supplied to the negative electrode plate first;
A method for treating a nuclear power plant wastewater containing ethanolamine, comprising the step of supplying negative electrode treatment water treated on the side of a negative electrode plate to a positive electrode plate side.
11. The method of claim 10,
Wherein the initial pH of the feed water supplied to the electrolytic apparatus is 6 or less or 9 or more.

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