KR20030095479A - The resolution method of the non-resolutive material - Google Patents

Abstract

PURPOSE: Provided is a method for treating wastewater containing recalcitrant compounds to increase wastewater treatment efficiency. CONSTITUTION: The method comprises a steps of introducing wastewater to an additional reactor(1) before or after performing main processes of conventional wastewater treatment method, wherein the reactor(1) is filled with catalyst compound(11) being comprised of 80 to 90 wt.% of carbon, 5 to 10 wt.% of iron oxide and 5 to 10 wt.% of magnesium and has electrodes(12b) therein, and 5 to 100V of direct current is applied to the electrodes(12b) to convert non biodegradable material in wastewater to a biodegradable material.

Description

The resolution method of the non-resolutive material}

The present invention provides a method of decomposing hardly decomposable substances, in particular, by removing harmful components contained in high concentration organic wastewater or wastewater containing hardly decomposable substances having high COD and high phosphorus and nitrogen compounds, and converting the hardly decomposable substances into degradable substances. The present invention relates to a method for decomposing hardly decomposable substances for supplying purified water by removal. In a known wastewater treatment method, a catalyst mixture is filled before and after the present reaction and passed through an additional reaction tank in which electrodes are interpolated. Therefore, the catalyst is used as an electric medium by applying a low voltage (5 to 18 V) DC power to the electrode while aeration using at least one of air, acetone, hydrogen peroxide, and iodine with a high content of ions. It promotes the removal of harmful substances including various organic substances and also the degradability of salt including salt By using the method of converting materials into degradable materials, it can effectively remove harmful organic materials such as macromolecules, nitrogen compounds and phosphorus compounds, as well as hardly decomposable materials, and prevent overload of wastewater treatment equipment to enable economical operation and catalyst Since the reaction occurs continuously, the present invention relates to a method for decomposing hardly decomposable substances, which can obtain the effect of using the wastewater treatment apparatus for a long time.

With the rapid increase of urban population and the rapid development of various industries, the pollution of living environment is getting serious day by day, moreover, pollution by sewage and industrial wastewater is the most urgent threat that threatens human's healthy life and endangers the life of natural life. It's one of the problems.

Currently, the wastewater treatment method is largely divided into physical, chemical, and biological methods. Among them, biological treatment methods are known to be suitable for treatment of wastewater containing a large amount of organic compounds.

However, high concentrations of organic wastewaters with high COD, high SS, and high nitrogen and phosphorus compounds are not only diverse but also transferable, including livestock wastewater, landfill leachate, and organic wastewater from various chemical manufacturing plants. When many of them are treated by biological treatment methods as they are, the treatment efficiency is lowered, as well as the growth of microorganisms as well as the death problem occurs, there is a problem such as problems in the efficiency of the device.

For example, livestock wastewater is a difficult-to-treat wastewater that is difficult to treat with high concentrations of organic wastewater, has a bad odor, and livestock farms are concentrated more upstream than water sources, so surface water and soil, as well as water supplies, are very serious. The situation is contaminated.

Conventional methods for treating livestock wastewater are treated with several chemical treatment methods and then treated with biological treatment methods, in which the solids and liquids discharged are composted into solid fertilizers and liquid fertilizers, respectively. Methods are carried out in a way that reduces the land.

However, the above methods not only have low efficiency, but also have a problem of securing a large area for installing the wastewater treatment apparatus, and require a manager to manage the process smoothly, the apparatus is complicated, and the scale is not suitable for practical application. There is this.

On the other hand, various methods such as sequential batch reactor (SBR) method, an anaerobic-aerobic process, AO (anaerobic aerobic activated sludge method), A2O method, and intermittent aerated activated sludge method are developed for wastewater treatment. have. However, these methods are a method that can be applied to general wastewater having a low concentration of pollutants as a method of processing by aeration tank, anaerobic tank and anoxic tank, or by sludge return and internal return. In addition, there is a problem such as limiting the amount of load, securing of active microorganisms, economic efficiency, etc. is not being effectively applied to high concentration organic wastewater treatment.

In recent years, research and attention has been focused on a biological film process using an immobilized carrier. Currently, biofilm method is widely used for small and medium-sized sewage treatment. Compared with activated sludge method, it is easy to maintain and has strong advantages in influx load fluctuations and does not cause sludge swelling, but it uses biofilm by adherent microorganisms. As a result, the treatment of high concentration organic wastewater has difficulty in securing stable water quality due to problems such as biofilm desorption due to excessive growth of microorganisms and clogging of pores according to types of media.

In addition, most wastewater treatment methods have a very low treatment efficiency of hardly decomposable substances, and the COD content of the treated waters is practically high, and since the hardly decomposable substances are not decomposed and removed, the treatment efficiency may actually decrease. In addition, the problem of environmental pollution due to hardly decomposable substances is serious.

Accordingly, an object of the present invention is to provide a decomposition method of a hardly decomposable substance which can improve wastewater treatment efficiency by decomposing and removing the hardly decomposable substance into a decomposable substance.

Another object of the present invention is to remove harmful components and hardly decomposable substances from high concentration organic wastewater, especially wastewater having high COD, high SS content, nitrogen compounds and phosphorus compounds or wastewater containing hardly decomposable substances by using the method of the above object. It is to provide a wastewater treatment method for purification.

Still another object of the present invention is to provide a wastewater treatment method capable of obtaining a long-term use of the wastewater treatment apparatus because the catalytic reaction occurs continuously while the wastewater or air treatment efficiency is excellent.

In order to achieve the above-mentioned objects as well as other objects that can be easily expressed, in the present invention, in the known wastewater treatment method, when the catalyst mixture is filled before and after the present reaction and the electrode is inserted, Therefore, by applying a DC power of 5-100V to the electrode while aeration using at least one of air, acetone, hydrogen peroxide, and iodine having a high content of ions, the catalyst is used as an electric medium and promotes decomposition reaction in the catalyst. By removing harmful substances including various organic substances and converting non-degradable substances including salts into degradable substances, high-efficiency substances such as high molecular organic substances and nitrogen compounds and phosphorus compounds as well as non-degradable substances are effectively removed and wastewater treatment Economical operation is possible by preventing overload of the device. Rock, and the catalytic reaction take place continuously, so there can be obtained an effect which can be used for waste water treatment apparatus for long periods of time.

1 is a schematic conceptual diagram of an apparatus for treating wastewater applied in the method of the present invention.

* Explanation of symbols for the main parts of the drawings

1: addition reactor 2: ionization air generator

3: iodine reservoir 4: acetone reservoir

5: hydrogen peroxide storage tank 6: power unit

11 catalyst mixture 12a, 12b electrode

13: width pipe 14: wastewater inlet

15: treated water discharge pipe 21: air inlet

22: air outlet 23: body

24: positive electrode 25: negative electrode

26: catalyst mixture molded body 27: coupling member

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

1 is a schematic conceptual diagram of a wastewater treatment apparatus to which the method of the present invention is applied.

The decomposition method of the hardly decomposable substance according to the present invention is a known wastewater treatment method, which includes a catalyst mixture 11 filled before and after the main reaction and an addition reactor 1 in which electrodes 12a and 12b are inserted. In some cases, the catalyst mixture 11 is electrically mediated by applying a DC power of 5 to 100 V to the electrodes 12a and 12b while aeration using at least one of air, acetone, hydrogen peroxide, and iodine with a high content of ions. It is used as to promote the decomposition reaction in the catalyst mixture (11) to remove the harmful substances including various organic matters, and to convert and remove the hardly decomposable substances containing salts into degradable substances.

The wastewater treatment apparatus to which the method of the present invention is applied is roughly composed of an addition reaction tank (1), an ionizing air generating tank (2), an iodine storage tank (3), an acetone storage tank (4), a hydrogen peroxide storage tank (5), and a power supply unit (6). The addition reactor 1 may be provided with a water level controller 17 as needed, and when the excess waste water is introduced into the addition reactor 1, a flow control tube 18 for returning the waste water is installed. In front of the wastewater inlet 14, a flow control valve 19 may be installed.

The level controller 17 has a built-in detection means to detect the change in the water level and to operate the flow control valve 19 so that the water level is almost always constant.

In addition to the above-mentioned reaction tank 1, all the pretreatment means commonly used in the technical field to which the present invention belongs may be used.

The addition reaction tank 1 has a wastewater inlet 14 and a treated water discharge pipe 15 formed therein, the catalyst mixture 11 is filled and the electrodes 12a and 12b are interpolated, and an aeration pipe is disposed for aeration at the bottom. 13), and optionally, at least one of air generated from the ionized air generator 2, iodine from the iodine reservoir 3, acetone from the acetone reservoir 4, and hydrogen peroxide from the hydrogen peroxide reservoir 5 The above is used to enable aeration.

Control valves 7a and 7b and a pump 8 are provided in the middle of the width pipe 13 so that the air generated from the ionizing air generating tank 2, the iodine from the iodine storage tank 3 and the acetone storage tank 4 are provided. From the acetone, hydrogen peroxide reservoir 5 can be adjusted the amount of at least one or more mixtures of hydrogen peroxide.

The electrodes 12a and 12b may use conventional plate-shaped electrodes or rod-shaped electrodes, and may be variously manufactured according to the shape of the treatment tank.

At least one additional reaction tank 1 may be provided, and may be formed in multiple stages depending on the characteristics of the wastewater, the amount of the treated water, the treatment place, and the like.

The ionization air generator (2) is for supplying air to the addition reaction tank (1), but through the high-pressure electrode of several KV or more to supply air with a high content of ions to maximize the treatment efficiency of the waste water, the insulating material 28 and A compartment is formed by the body 23, and an air inlet 21 and an air outlet 22 are formed, and the anode mixture 24 and the cathode 25 are formed by using the coupling member 27 to form the catalyst mixture compact 26. ), But the positions of the pores 29 and 29 'formed in the anode 24 and the cathode 25 coincide with each other.

The iodine reservoir (3), the acetone reservoir (4) and the hydrogen peroxide reservoir (5) store solid iodine, gaseous acetone and hydrogen peroxide, and gaseous iodine, acetone and hydrogen peroxide are about 2 millimoles per 10 liters of wastewater. To be supplied in an amount of.

The power supply unit 6 supplies power to the positive electrode 24 and the negative electrode 25 of the electrodes 12a and 12b of the additional reaction tank 1 and the ionizing air generating tank 2, but according to the type and nature of the wastewater. The electrodes 12a and 12b of the addition reactor 1 are supplied with a DC power supply of 5 to 100 V, preferably a power supply of about 24 V, and a power supply of about 100 V in the case of benzene, depending on the properties of the waste water. A high voltage direct current power supply of several KV or more is applied to the positive electrode 24 and the negative electrode 25 of (2).

Control valves 9a, 9b, 9c, and 9d are installed between the ionization air generator 2, the iodine reservoir 3, the acetone reservoir 4, the hydrogen peroxide reservoir 5 and the pump 8, thereby providing an ionization air generator. The amount of air generated from (2), iodine from iodine reservoir (3), acetone from acetone reservoir (4), and hydrogen peroxide from hydrogen peroxide reservoir (5) are adjusted to achieve the most ideal mixture.

The additional reaction tank 1 configured as described above is installed before and after the main reaction tank in the known wastewater treatment apparatus. Looking at the process of treating the wastewater through this, the wastewater inlet port before or after the main reaction tank in the known wastewater treatment apparatus ( 14) and the addition reaction tank (1) is connected and installed using the treated water discharge pipe (15).

At this time, if it is installed before the main reaction tank is used for pretreatment of the main reaction, if it is installed after the main reaction tank is used for post-treatment.

First, when wastewater flows into the additional reaction tank 1 through the wastewater inlet 14, a low voltage DC power is applied to the electrodes 12a and 12b, and the catalyst is supplied by a low voltage DC power applied to the electrodes 12a and 12b. As the mixture 11 is electrolyzed, organic substances are decomposed and removed, and at the same time, many contaminants in the wastewater are removed and the hardly decomposable substances are decomposed into decomposable substances.

At this time, adjust the DC voltage of the electrode according to the type and characteristics of the incoming wastewater, but wastewater containing 5-15V, usually 24V in the case of wastewater containing substances that are easily decomposed, wastewater containing substances that are difficult to decompose In the case of applying a voltage of about 100V, while the wastewater amount of the additional reaction tank 1 is detected by the water level regulator 17, the flow control valve 19 is automatically opened and closed according to the detection result to adjust the flow rate.

In addition, as a small amount of iodine, acetone and hydrogen peroxide flows in from the iodine reservoir (3), the acetone reservoir (4) and the hydrogen peroxide reservoir (5), the oxidation reaction of organic matter is promoted, and thus, Not only decomposition but also harmful contaminants are converted into non-hazardous substances.

In addition, the air containing a large amount of ions promoting electrolysis from the ionizing air generator 2 is introduced to aeration to maximize the pollutant treatment efficiency.

The ionization air generating tank 2 is ozone-oxidized by ozone generated by a high voltage of several KV or more, and increases oxidation reaction and generates air having a high content of ions. The catalyst mixture molded body 26 formed by mutually bonding with a binder is bonded to the positive electrode 24 and the negative electrode 25 by the coupling member 27, and a high voltage is applied from the power supply unit 6 while the catalyst mixture molded body 26 and the air are applied. Touches and the components in the air are ionized.

If the wastewater treatment efficiency is not satisfactory after the first treatment, the additional reaction tank 1 may be installed in multiple stages to improve the treatment efficiency.

The catalyst mixture 21 is preferably composed of 80 to 90% by weight of carbon, 5 to 10% by weight of iron oxide (Fe ₂ O ₃ ), and 5 to 10% by weight of magnesium. Happens.

In the catalyst mixture, activated carbon is used as the carbon, and when carbon is used in excess of 90% by weight, current flows too much, which improves performance, but overloads the power supply, and iron oxide is used in excess of 10% by weight. If the redox reaction is effective, but there is a problem of secondary pollution due to the generation of a lot of iron ions, if the magnesium is used in excess of 10% by weight has a disadvantage that is not economical, the three When the catalyst components are each used in less than the above ratio, there is a problem that the wastewater treatment efficiency is lowered.

Looking at the operation of each step in the method of the present invention made as described above are as follows.

The reaction is performed by applying electricity to the catalyst mixture (11) consisting of 80 to 90% by weight of carbon, 5 to 10% by weight of iron oxide (Fe ₂ O ₃ ), and 5 to 10% by weight of magnesium, without containing any liquid components such as any solvent. This continuously occurs, so that the pollutants in the wastewater can be easily oxidized and decomposed and removed, and the catalyst efficiency can be maintained for a long time due to the repeated action of oxidation and reduction of the pollutants. .

The reaction when applying electricity to the electrodes 12a and 12b of the addition reactor 1 containing the catalyst mixture 11 mixed with carbon, iron oxide and magnesium is carried out by the mediated electrochemical oxidation (MEO) and the semiconductor theory. As described above, instead of the electrolytic solution, the above-described solid catalyst, activated carbon (carbon), or magnesium and direct current may be modified by a modified MEO process.

Each catalyst particle is distributed in the positive electrode and the negative electrode by using activated carbon and iron oxide adhered to the activated carbon as a catalyst.

The oxidant produced at the anode reacts with the organic matter adsorbed on the numerous micropores in the activated carbon itself, which oxidizes and decomposes the organic material, and then oxidizes the organic material continuously by being oxidized at the anode. As a water-soluble process to be used, organic matter is almost completely destroyed through this, and carbon and hydrogen in the organic material are converted into carbon dioxide and water, and almost all of them are mineralized. The process also has the ability to dissolve radioactive materials in mixed wastes that contain chemicals and are radioactive.

On the other hand, when water is removed from the reaction in which water is generated, the reaction is accelerated, and water in the vicinity of the electrodes 12a and 12b is easily removed, thereby allowing the air to be introduced, thereby promoting the reaction by magnesium, which is a metal lacking oxygen.

Mg _x-1 + H ₂ O → Mg _x O + H ₂

Therefore, the effect of the enhancer is increased by removing the moisture around the electrodes 12a and 12b by magnesium.

Oxygen present on the surface of magnesium can attract protons, so oxygen can act basic, and the second ionization potential is greater than its first ionization potential because electron removal from cations is more difficult than ionization of neutral atoms.

⁺ Mg (g) → Mg ²⁺ + e ^-

Thus, a metal oxide catalyst such as magnesium is used to remove high molecular weight organic matter and ozone, and not necessarily limited to magnesium, and all metal oxides having the above functions can be used, but magnesium is particularly preferable.

On the other hand, the desorption reaction causes oxygen in the acid gas generated during decomposition of organic matter to combine with carbon of activated carbon to cause an oxidation reaction, and desorption reaction proceeds in the capillary of activated carbon, which causes loss of carbon component of activated carbon. In this case, the specific surface area of the capillary tube is increased, and the adsorption performance is improved while repeating adsorption and desorption. The loss of adsorbent caused by the reaction of oxygen in the adsorbed acid gas with carbon of activated carbon to produce carbon dioxide (CO ₂ ) is compensated.

Activated carbon is mostly carbonaceous charcoal with strong adsorption, and adsorption is a kind of interfacial phenomenon in which powdery substances such as activated carbon or silica gel absorb contaminants to the surface. The surface area of the material must be large. Activated charcoal has a large number of pores, the total area of its thin pore wall, or surface area, usually 500 to 150 m ² per gram, and it adsorbs so many chemicals that it is used as a deodorant for refrigerators. The adsorption components are not only influenced by the fine pore structure but also by the chemical properties of the activated carbon surface. When activated carbon is added to the waste water and stirred, the concentration of organic matter in the water is significantly reduced. This is because activated carbon adsorbs them. Since activated carbon is made of wood, coal, etc. as a raw material, its original main ingredient is organic matter.

Referring to the electrolysis in the addition reactor 1, the oxidant produced on the surface of the anode reacts with the organic material to oxidatively decompose the organic material, and at the same time, it is reduced again and then regenerated by being oxidized on the electrode surface to continuously produce the organic material. As a process that uses the principle of oxidization, organic matter is completely destroyed and ultimately carbon and hydrogen in the organic material are converted into carbon dioxide and water, which is almost always inorganic.

In the reaction of positive electrode ^{_{H 2 O → H + + OH}} - , and the pH a reduction in the increase in the ion H ⁺ ions decrease, ^electron-in scheme of OH (Electron: e ^-) is increased oxidative I got lost. In addition, by the electrolysis reaction, Cl ₂ (chlorine gas) becomes a gas at the anode and is released into the atmosphere, and hypochlorous acid (HOCl) is generated.

^{_{H 2 O → H + + OH}} -

NaCl → Na ^{+ +} Cl ^-

_{^{4OH - → 2H 2 O + O}} 2 + 4e -

2Cl ^- → Cl ₂ + 2e ^-

_{Cl 2 + H 2 O → HOCl} + H + + Cl -

In the reaction of the negative electrode H ₂ O → H ⁺ + OH ^-, and the pH is raised to increase the ion with H ⁺ reduction of the ion, ^electron-in scheme of OH (Electron: e ^-) increased reducing power is increased, the hydrogen gas Is generated.

^{_{H 2 O → H + + OH}} -

NaCl → Na ^{+ +} Cl ^-

_{2H 2 O + O 2 + 4e} - → 4OH -

Na ^{+ +} e ^- → Na

Na + OH → NaOH

In addition, the oxidation and neutralization of the basic material and the neutral material is performed by the acidic oxidation water generated at the anode.

* Basic substances

2NH ₃ + 3HOCl → N ₂ + 3HCl + 3H ₂ O

NH ₃ + HCl → NH ₄ Cl

(CH ₃ ) ₃ N + HOCl → (CH ₃ ) ₃ NO + HCl

* Neutral

(CH ₃ ) ₂ S + 3HOCl → (CH ₃ ) ₂ SO ₃ + 3HCl

CH ₃ CHO + HOCl → CH ₃ COOH + HCl

C ₆ H ₅ CHCH ₂ + HOCl → C ₆ H ₅ CHOHCH ₂ Cl

In addition, the following reactions occur by the alkaline reduced water produced in the negative electrode.

H ₂ S + NaOH → N ₂ S + H ₂ O

Na ₂ S + H ₂ S → 2NaSH

CH ₃ SH + NaOH → CH ₃ SNa + H ₂ O

CH ₃ COOH + NaOH → CH ₃ COONa + H ₂ O

And organophosphorus compounds are processed by hydrolysis (electrolysis).

In other words, a tertiary ester there is discharged to the phosphorus and alcohol by hydrolysis, base catalysis is [OH ^-] and is primarily by both the reaction of the ester concentration-oxygen bond is decomposed, the reaction of carbon acid ester Is hydrolyzed by a base catalyst, and if there is a substituent which provides positive charge to phosphorus by interaction with oxygen having high electronegativity and increases the electrophilicity of phosphorus, the hydrolysis rate is increased, and the decomposition product of organophosphate Becomes phosphorus and alcohol.

(Formula addition)

When a protein reacts with iodine, the protein is broken down by moisture in iodine and air.

Recently, studies have been reported in which allylglycine is introduced at a specific site using an inhibitory t-RNA, and the protein is degraded using iodine (J. Am. Chem. Soc. 2000, 122, 7402

In other words, when allylglycine is introduced at a specific position and reacted with iodine, a ring intermediate formed by iodine is formed, which is divided into two peptides having a lactone and an amine by reacting with water.

This degradation depends largely on the location of the allylglycine that is introduced, which is determined by how well the water in the air is accessible.

By this reaction, trypsinogen, a precursor protein, is changed to trypsin, an active protein.

The complex action of acetone and hydrogen peroxide is as follows.

H ₂ O ₂ ↔ H ⁺ + HO ₂

^{_{CH 3 COCH 2 + H + +}} H and HO ₂ ^-

CH ₃ COCH ₂ + H ⁺ + H ₂ O ₂

_{CH 3 COCH 3 + H 2 O} 2 -

When acetone is used alone, one hydrogen atom moves to an oxygen atom in the CH ₃ atom group.

CH ₃ -CO-CH ₃ ↔ CH ₃ -COH = CH ₂

CH ₃ COCH ₂ + H ⁺ → CH ₃ -COH-CH ₂ → CH ₃ COCH ₃

CH ₃ -CO-CH ₃ ↔ CH ₃ -COH-CH ₂

→ CH ₃ COCH ₃

The generated OH radical is in the middle of producing material hydroperoxide oxy radicals (Hydroperoxyradical: HO ₂ ^-) and the superoxide radical (Superoxide radical: O ₂ ^-) to generate and quickly decompose many organic substances of the water contaminants, biodegradation of the organic compound It improves the castle and suppresses the production of sludge.

^{_{HO 2 → H + + O 2}} -

When hydrogen peroxide alone is used, it has the following effects.

OH + H ₂ O ₂ → HO ₂ + H ₂ O

_{^{OH + HO 2 - → OH -}} + HO 2

^{_{CO 3 - + H 2 O 2}} → HO 2 + HCO 3

In addition, iron oxide decomposes organic compounds in wastewater by powerful oxidation and reduction as already known, and can be used for a long time by automatically repeating oxidation and reduction reactions by electrodes.

On the other hand, the air generated from the ionizing air generator 2 contains a large amount of ionized oxygen and hydrogen atoms, which are used to aeration the wastewater to promote the decomposition of organic materials as well as the oxidation of various organic materials and harmful substances. This improves the efficiency of wastewater treatment.

A catalyst mixture molded body which is introduced into the air inlet 21 of the ionization air generator 2 and is moved to the air outlet 22, but is coupled to the positive electrode 24 and the negative electrode 25 by the coupling member 27. When high-pressure direct current electricity is applied to (26), contaminants such as air impurities and organic matters are decomposed and removed by the catalytic action, and air having a high content of ionized oxygen and hydrogen is introduced into the addition reaction tank (1).

When the high concentration organic wastewater was treated by the above action, nitrogen compounds were removed by more than 80% on average, phosphorus compounds were removed by more than 90%, and COD removal rate of condensate was more than 80% on average in the high-treatment experiments.

As described above, according to the present invention, in the known wastewater treatment method, before or after the present reaction, the catalyst mixture is filled and the electrode is inserted into the reactor, where the high content of ions, air, acetone, hydrogen peroxide, By applying a DC power of 5-100V to the electrode while aeration using at least one of the iodine, the catalyst is used as an electrical medium and promotes the decomposition reaction in the catalyst to remove harmful substances including various organic substances, and also contains salt By using the method of converting the hardly degradable material into the degradable material, it effectively removes not only the high-molecular organic materials, the harmful substances such as nitrogen compounds and phosphorus compounds, but also the hardly decomposable substances, and prevents the overload of the wastewater treatment system to enable economical operation. In addition, wastewater treatment plant The effect was achieved with long-term use.

Claims (6)

In the known wastewater treatment method, a direct current power source is applied to the electrodes 12a and 12b while passing through the addition reactor 1 in which the catalyst mixture 11 is filled and the electrodes 12a and 12b are inserted before and after the main reaction. Therefore, by using the catalyst mixture (11) as an electric medium and by promoting the decomposition reaction in the catalyst mixture (11) to remove harmful substances including various organic substances, and to convert and remove the hardly decomposable substances containing salts into degradable substances Decomposition method of a hardly decomposable substance. The method for decomposing hardly decomposable substances according to claim 1, which is used as a pretreatment step before the present reaction of wastewater treatment. The method for decomposing hardly decomposable substances according to claim 1, which is used as a post-treatment step after the main reaction of wastewater treatment. The method according to claim 1, wherein at least one of air having a high content of ions from the ionizing air generating tank (2), iodine from the iodine storage tank (3), acetone from the acetone storage tank (4), and hydrogen peroxide from the hydrogen peroxide storage tank (5). A method for decomposing a hardly decomposable substance, which is reacted while aeration is performed using one or more kinds. The method of claim 1, wherein a DC power source of 5 to 100 V is applied to the electrodes (12a, 12b). The method of claim 1, wherein the catalyst mixture is composed of 80 to 90% by weight of carbon, 5 to 10% by weight of iron oxide, and 5 to 10% by weight of magnesium.