JPH08299970A - Treatment of waste water including nitrogen-containing compound - Google Patents

Abstract

PURPOSE: To reduce equipment cost or running cost by treating a waste water at a specific temp. in the presence of at least one kind of a halogen compound selected from a group composed of chlorine compounds, bromine compounds and iodine compounds to treat the waste water including a nitrogen-containing compound with a high purifying performance. CONSTITUTION: The waste water 4 pressurized by a pump 3 is supplied to a device at a prescribed flow rate corresponding to a prescribed space velocity. An air pressurized by a compressor 6 is supplied at a flow rate corresponding to a prescribed theoretical oxygen demand. Further, the gas-liquid mixture is heated by a heat exchanger 2, introduced into a wet oxidation column 1 in which a catalyst is packed, treated at >=100 deg.C to <370 deg.C under heating by a heater 9 and the treated water is cooled in the heat exchanger 2 and introduced into a gas-liquid separator 5. And the water level of the gas-liquid separator 5 is kept constant by operating a water level control valve 7 and also the pressure is kept constant by a pressure control valve 8. At such a time, the waste water is treated in the presence of at least one kind of halogen compound selected from a group composed of chlorine compounds, bromine compounds and iodine compounds.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet oxidation treatment of wastewater containing a nitrogen-containing compound in the presence of a solid catalyst (hereinafter, wet oxidation treatment using a solid catalyst and its method are referred to as a catalyst wet oxidation treatment and a catalyst wet treatment, respectively). Also referred to as an oxidation treatment method), the nitrogen-containing compound in the wastewater is purified to render the wastewater harmless. More specifically, the present invention provides
Chemical plant, plating industrial equipment, leather manufacturing equipment, metal industrial equipment, metal mining equipment, food manufacturing equipment, pharmaceutical manufacturing equipment, textile industrial equipment, paper pulp industrial equipment, dyeing dye industrial equipment, electronic industrial equipment, machine industrial equipment, printing Of industrial wastewater typified by plate making equipment, glass manufacturing equipment, photographic processing equipment, etc., particularly relates to a method for detoxifying wastewater by purifying nitrogen-containing compounds in wastewater containing nitrogen-containing compounds by catalytic wet oxidation treatment. .

[0002]

2. Description of the Related Art In sea areas, lakes, rivers, etc., red tides and musty odors have long been a problem due to eutrophication, but the cause is contained in wastewater discharged into the waters. It is caused by nutrients such as nitrogen. For this reason, wastewater regulations on nitrogen have been enforced, but nitrogen-containing compounds cannot be sufficiently removed only by performing treatment by the conventional activated sludge method or the like, and thus a denitrification step must be newly provided in many cases.

Conventionally, as a method of treating wastewater containing a nitrogen-containing compound, a biological treatment method such as an activated sludge treatment method, a combustion treatment method, a coagulation treatment method using an anionic polymer flocculant, etc. have been adopted. .

On the other hand, as a method for treating wastewater containing a nitrogen-containing compound, a method of wet oxidation using a catalyst has been proposed (Japanese Patent Publication No. 59-19757, JP-A-5-13802).
No. 7). This is a method of treating wastewater at a temperature of 100 to 370 ° C., under pressure conditions for maintaining a liquid phase, and in the presence of a specific catalyst under the supply of a gas containing oxygen. According to this treatment method, the nitrogen-containing compound in the wastewater can be converted to nitrogen gas, water, carbon dioxide gas, inorganic salt, ash, lower molecular weight organic matter and the like for purification.

The catalytic wet oxidation treatment method can treat the nitrogen-containing compound with high efficiency, but it is preferable if the purifying property can be further improved. Further, in the catalytic wet oxidation treatment, it is 100 to 37.
Since the treatment is carried out under the temperature condition of 0 ° C. and the pressure condition that the waste water retains the liquid phase, the reaction tower can withstand the temperature condition and the pressure condition,
A device such as a heat exchanger is required. Therefore, if the reaction conditions can be reduced to a lower temperature and a lower pressure, and the amount of waste water treated per unit volume of the catalyst can be increased, the equipment cost and the running cost can be reduced, which is preferable.

[0006]

DISCLOSURE OF THE INVENTION An object of the present invention is to effectively treat wastewater containing a nitrogen-containing compound, which is more economical and more economical in purification in a catalytic wet oxidation treatment method. It is to provide a processing method.

More specifically, it is an object of the present invention to provide a method capable of treating wastewater containing a nitrogen-containing compound with a higher degree of purification and further reducing the equipment cost and running cost. That is, if the treatment at a lower temperature and a lower pressure is enabled by enhancing the purifying property of the nitrogen-containing compound, the temperature and pressure of the wet oxidation tower, the heat exchanger, etc. can be lowered, so that the equipment cost etc. can be reduced. . In addition, if processing at a higher liquid hourly space velocity is possible, the apparatus can be downsized and the amount of catalyst can be reduced,
This also makes it possible to reduce equipment costs, running costs, and the like.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have used a solid catalyst and a chlorine compound and a bromine compound in wet oxidation treatment of wastewater containing a nitrogen-containing compound. It has been found that the presence of at least one halogen compound selected from the group consisting of and an iodine compound in the wastewater makes it possible to treat the nitrogen-containing compound at a dramatically high efficiency. The present invention has been completed based on this finding. The present invention is specified as follows.

(1) Wet oxidation of wastewater containing a nitrogen-containing compound using a solid catalyst under the conditions of a temperature of 100 ° C. or higher and lower than 370 ° C. and a pressure at which the wastewater maintains a liquid phase under the supply of oxygen-containing gas. A method for treating wastewater containing a nitrogen-containing compound, which comprises treating the wastewater in the presence of at least one halogen compound selected from the group consisting of chlorine compounds, bromine compounds and iodine compounds.

(2) A method for treating wastewater containing a nitrogen-containing compound as described in (1) above, wherein the halogen compound is a bromine compound.

(3) The nitrogen-containing compound is ammonia,
The method for treating wastewater containing the nitrogen-containing compound according to the above (1) or (2), which is at least one compound selected from the group consisting of ammonium salts, hydrazine, hydrazinium salts, amine compounds, amide compounds and amino acid compounds.

The present invention will be described in detail below.

At least one halogen compound selected from the group consisting of a chlorine compound, a bromine compound and an iodine compound according to the present invention is particularly limited as long as it contains a chlorine atom, a bromine atom and an iodine atom, respectively. However, it is preferably a compound which produces a chloride ion, a bromide ion, or an iodide ion by being dissolved in waste water or decomposed in the wet oxidation treatment of the waste water, respectively. The halogen compound according to the present invention is preferably one that is soluble in water, but one that is insoluble or sparingly soluble in water can also be used. However, when a halogen compound that is insoluble or sparingly soluble in water is used, it is more preferable that the halogen compound is suspended in water.

Further, among the halogen compounds, the bromine compound has the highest treating activity and is most effective for treating the nitrogen-containing compound. Also, chlorine compounds are somewhat less effective than bromine compounds. Iodine compounds are more expensive and somewhat less effective than bromine compounds. Further, the fluorine compound may adversely affect the material of the device when the fluorine compound is decomposed to generate fluoride ions. Therefore, bromine compounds are most preferred.

The following can be mentioned as specific examples of the chlorine compound according to the present invention. For example, acids such as hydrochloric acid, hypochlorous acid, chlorous acid, chloric acid and perchloric acid; salts of the above acids such as sodium chloride, sodium hypochlorite and alkylammonium chloride; methylene chloride, ethylene chloride, chloroform, Examples include organic chlorine compounds such as chloroacetic acid.

Examples of the bromine compound according to the present invention include the following. For example, acids such as hydrobromic acid, hypobromic acid, bromic acid; salts of the above acids such as sodium bromide, potassium bromate and alkylammonium bromide; methylene bromide, ethylene bromide, bromoform, bromoacetic acid, etc. It is an organic bromine compound.

Examples of the iodine compound according to the present invention include the following. For example, hydroiodic acid, hypoiodic acid, iodic acid, periodic acid; salts of the above acids such as potassium iodide; organic iodine compounds such as methylene iodide, ethylene iodide, iodoform and iodoacetic acid.

The concentration of the halogen compound according to the present invention (the concentration represents the concentration converted as a halogen atom of the halogen compound) is preferably 10 mg / liter or more and 100 g / liter or less, and 50 mg / liter or more and 10 g or more. / Liter or less is more preferable,
It is more preferably 200 mg / liter or more and 2 g / liter or less. Halogen compound concentration is 10 mg
If it is less than / liter, the effect is small. On the other hand, when the concentration of the halogen compound exceeds 100 g / liter, the effect corresponding to the concentration cannot be obtained, and the salt concentration of the treated water becomes high, so that the salt is precipitated in the reaction device and the reaction device is clogged. Therefore, it is not preferable.

The ratio of the concentration of halogen atoms in the wastewater to the concentration of total nitrogen in the wastewater is 0.0 by weight.
It is preferably from 01 to 100 times, and more preferably from 0.01 to 10 times. When the above ratio is less than 0.001 times, a sufficient effect cannot be obtained, while the above ratio is 100.
This is because when the amount is more than twice, the treatment efficiency itself of the nitrogen-containing compound is high, but the effect corresponding to the halogen concentration cannot be obtained, which is not preferable.

In the present invention, it is not necessary to add the halogen compound to the wastewater when the halogen compound is dissolved in the wastewater at an appropriate concentration, but when the halogen compound is not contained in the wastewater at an appropriate concentration. For example, when the amount is less than 10 mg / liter, it is preferable to add a halogen compound so that the halogen atom falls within the above range.

When the halogen compound is added, the addition method is not particularly limited, but for example, a predetermined amount of the halogen compound may be added to the wastewater in the wastewater tank.
An aqueous solution of a halogen compound may be supplied at a predetermined flow rate in the middle of a pipe for supplying wastewater into the treatment apparatus and / or to a reaction tower or the like.

In the present invention, the halogen compound may be of a single type, or may be of a plurality of types. Further, in order to add the halogen compound to the wastewater containing the nitrogen-containing compound, the wastewater containing the halogen compound may be mixed with the wastewater containing the nitrogen-containing compound. In this case, a plurality of types of wastewater can be simultaneously and efficiently subjected to catalytic wet oxidation treatment for purification.

In many cases, the halogen compound according to the present invention is a halide ion in the treated water after the catalytic wet oxidation treatment. The halide ion is an anion and can be recovered by an ion exchange resin or an ion exchange membrane. The halide ions thus recovered can be reused and added to the wastewater again for more efficient treatment of the wastewater.

The halogen compound produces a halide ion under catalytic wet oxidation conditions by dissolution, wet oxidation treatment, wet thermal decomposition treatment, etc., and further, hypobromite ion (BrO).
^- ), Bromate ion (BrO ₃ ⁻ ), hypochlorite ion (ClO ₂ ⁻ ), iodate ion (IO ₃ ⁻ ), and the like, are considered to generate halogen oxygen acid ions.
The reaction between the oxygen acid ion of halogen obtained by the oxidation of the halogen compound and the nitrogen-containing compound, particularly ammonia and / or ammonium salt proceeds very efficiently, and this reaction causes the nitrogen in the nitrogen-containing compound to react with nitrogen gas. It is thought that the reaction will be accelerated. At this time, the halogen in the oxygenate ion of the halogen is considered to become a halide ion. That is, the above-mentioned reaction between the oxygenate ion of halogen and the nitrogen-containing compound proceeds more rapidly than the case where the oxygen and the nitrogen-containing compound directly react. Therefore, in the presence of the halogen compound and the solid catalyst, the waste water is It is considered that the wet oxidation treatment of the nitrogen-containing compound contained in is promoted. The treatment promoting action of the nitrogen-containing compound due to the presence of the halogen compound is dramatically improved by the simultaneous presence of the solid catalyst, and the effect is small in the absence of the solid catalyst.

The nitrogen-containing compound according to the present invention is not particularly limited as long as it contains a nitrogen atom. For example, ammonia, ammonium salt, hydrazine, hydrazinium salt, amine compound, amide compound,
Examples thereof include amino acid compounds, nitrates, nitrites, nitro compounds, nitroso compounds, nitrosyl compounds and nitrogen-containing polymers.

The amine compound according to the present invention is a compound having an amino group in the molecule, and examples thereof include methylamine, ethylenediamine, triethanolamine, aniline and pyridine.

The amide compound according to the present invention is a compound having an amide group in the molecule, and examples thereof include formamide, dimethylformamide and urea.

Examples of the amino acid compound according to the present invention include glycine, aspartic acid, phenylalanine and tryptophan.

In particular, the nitrogen-containing compound is ammonia,
When it is at least one compound selected from the group consisting of ammonium salt, hydrazine, hydrazinium salt, amine compound, amide compound and amino acid compound (these compounds are also referred to as "ammonia nitrogen"), the treatment method of the present invention Is effective, and is more effective when it is an ammonia and / or ammonium salt. It is considered that the effect is remarkable because the reaction between the ammonium nitrogen and the oxygenate ion of halogen is particularly remarkable. Therefore, the wastewater treatment method of the present invention is particularly excellent in treating ammoniacal nitrogen.

The nitrogen-containing compound may be insoluble or sparingly soluble in water, but is preferably soluble in water. When treating a nitrogen-containing compound that is insoluble or sparingly soluble in water, it is preferable that the nitrogen-containing compound is suspended in water from the viewpoint of handling. The nitrogen-containing compound in the wastewater may be present as a single compound or may be mixed in plural types.

Even if the wastewater contains components other than the nitrogen-containing compound, such as COD component, there is no particular problem as long as it does not hinder the wet oxidation reaction according to the present invention.

The total nitrogen concentration in the wastewater to be treated in the present invention is not particularly limited, but is 50 mg.
/ Liter or more and 300 g / liter or less is effective, and preferably 200 mg / liter or more and 50 g / liter or less. When the total nitrogen is less than 50 mg / liter, the cost advantage of the catalytic wet oxidation treatment cannot be sufficiently obtained. On the other hand, when it exceeds 300 g / liter, the heat generated during the catalytic wet oxidation treatment becomes high, and there is a strong possibility that stable operation becomes difficult.

In the present invention, the pH of the treated water is not particularly limited, but it is effective that it is 3 to 12, and preferably 5 to 10. If the pH is lower than 3 or higher than 12, the treated water cannot be discharged as it is, and treatment such as further neutralization of the treated water may be required, which is not preferable.

In the catalytic wet oxidation treatment according to the present invention, the pH of the liquid during the catalytic wet oxidation treatment is preferably 3 to 1.
2, preferably 5 to 10 is preferably maintained. This is because if the wastewater during treatment or after treatment is strongly acidic or strongly alkaline, corrosion or embrittlement may be a problem depending on the material of the equipment. In particular, since a halogen compound is used in the treatment, these problems become more serious.

Therefore, in order to prevent the above-mentioned harmful effects, the pH of the liquid is adjusted to 3 after and / or during the catalytic wet oxidation treatment.
When the amount is less than the above value, it can be prevented by adding an alkaline substance or an aqueous solution thereof before and / or after the catalytic wet oxidation treatment of the wastewater.

The above-mentioned alkaline substance is a general term for hydroxides of alkali metals, hydrogencarbonates of alkali metals, carbonates of alkali metals and organic acid salts of alkali metals, and the following compounds are exemplified. You can Alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkali metal hydrogen carbonates such as sodium hydrogen carbonate; alkali metal carbonates such as sodium carbonate; alkali metal organic acid salts such as formic acid. Examples thereof include sodium and sodium acetate. However,
As the alkaline substance, one compound selected from the group consisting of an alkali metal hydroxide, an alkali metal hydrogen carbonate and an alkali metal carbonate is preferable.

The apparatus used for the catalytic wet oxidation treatment according to the present invention is not particularly limited as long as it can be used for the usual wet oxidation treatment, and any apparatus can be filled with the catalyst in the apparatus. , Any format may be used.

As the catalyst according to the present invention, any catalyst may be used as long as it is a solid catalyst having durability and activity under wet oxidation reaction conditions. As an example, titanium, zirconium and manganese are used as catalyst components. , Iron, cobalt, nickel, tungsten, cerium, platinum, palladium,
A solid catalyst containing at least one element selected from the group consisting of rhodium, ruthenium and iridium, or a solid insoluble or sparingly soluble compound in water, more preferably manganese, platinum, palladium, rhodium, It is a solid catalyst containing at least one element selected from the group consisting of ruthenium and iridium alone or a compound insoluble or hardly soluble in water.
Furthermore, an oxide or a composite oxide of at least one element selected from the group consisting of titanium, zirconium and iron, and at least one selected from the group consisting of manganese, platinum, palladium, rhodium, ruthenium and iridium. Most preferred is a solid catalyst containing a metal or metal compound of the element.

The catalyst according to the present invention is preferably composed of the substances specified above, and as the catalyst shape, various ones such as granular, spherical, pellet-like, and monolithic structure such as honeycomb can be adopted. it can.

The temperature during the wastewater treatment according to the present invention is 100 ° C.
Or more and less than 370 ° C., preferably 14 ° C. or more and less than 300 ° C. If the temperature during wastewater treatment exceeds 300 ° C, the reactor becomes expensive, which is not preferable. This is because if the temperature during wastewater treatment exceeds 370 ° C., it will exceed the critical temperature of water and the liquid phase cannot be maintained.

The pressure during the treatment of wastewater according to the present invention is not particularly limited as long as the wastewater retains the liquid phase.

The supply amount of the waste water according to the present invention is preferably in the range at a liquid hourly space velocity of 0.2 hr ^-1 or more 20 hr ^-1 or less of the catalyst. Liquid hourly space velocity is 0.2 hr ^-1
If it is less than the above, it is not preferable because it is disadvantageous in terms of cost, and if the liquid hourly space velocity exceeds 20 hr ^-1 , the total nitrogen treatment efficiency and the treatment efficiency of the chemical oxygen demand remain at an insufficient level, which is not preferable. .

The oxygen-containing gas according to the present invention is a gas containing oxygen gas, specifically, air, oxygen-enriched air, pure oxygen gas, generated from another plant, or a wet oxidation device. Various substances such as exhaust gas containing oxygen generated from the above can be mentioned. The oxygen-containing gas exemplified above can be mixed with some of them or appropriately diluted with nitrogen gas or other inert gas.

The lower limit of the supply amount of the oxygen-containing gas according to the present invention is preferably 0.5 times or more, more preferably 1 time or more, with respect to the theoretical oxygen demand of waste water. When the amount of oxygen supplied is less than 0.5 times the theoretical oxygen demand, the amount of oxygen is insufficient and purification is often incomplete, which is not preferable. Also, when the amount of oxygen supplied is 0.5 times or more and less than 1.0 times the theoretical oxygen demand, the oxygen amount will be insufficient, but if the concentration of nitrogen-containing compounds etc. in the waste water is low, This is because the wastewater can be treated so that the wastewater regulation can be sufficiently achieved. Further, if it is 1 time or more, it is preferable in terms of wet oxidation treatment, but increasing the amount of oxygen in wastewater more than necessary may be disadvantageous in terms of treatment cost. Therefore, the supply amount of the oxygen-containing gas can be appropriately changed and used depending on the composition of the wastewater and the treatment conditions.

Further, the upper limit of the supply amount of the oxygen-containing gas according to the present invention is preferably 10 times or less the theoretical oxygen demand amount of the waste water. This is because if the oxygen-containing gas exceeds 10 times, the removal rate of the nitrogen-containing compound such as ammonia will not be correspondingly improved, and the uneconomical aspect of the treatment will be increased.

The theoretical oxygen demand is the amount of oxygen required to decompose an oxidizable substance (a substance decomposed by an oxidant) in wastewater into water, carbon dioxide, nitrogen gas, inorganic salts and the like. Is. When the wastewater contains a reducible substance such as nitrate ion and nitrite ion (substance decomposed by a reducing agent), the oxygen demand required for decomposing the oxidizable substance causes the reduction The theoretical amount of oxygen is obtained by subtracting the amount of oxygen generated by reducing the volatile substance to nitrogen.

[0047]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto.

(Catalyst Preparation Example 1) Ferric nitrate and zirconyl nitrate were dissolved in water, aqueous ammonia was added to the solution to adjust the pH to 9, and the precipitate formed was filtered and washed after aging for one day. Dried cake at 120 ° C overnight,
Further, it was baked at 700 ° C. The obtained solid is a powder containing iron and zirconium, and when converted into the weight ratio of Fe ₂ O ₃ and ZrO ₂ , it is Fe in the analysis by the fluorescent X-ray method.
₂ O ₃ : ZrO ₂ = 60: 40.

Starch was added to the powder thus obtained,
Further, an aqueous solution of platinum nitrate was added so that the platinum atom content was 0.3% by weight with respect to the weight of the powder, and the resulting mixture was mixed well and then molded into pellets having an average particle diameter of 5 mm and an average length of 6 mm.
After drying at 10 ° C for 10 hours, it was calcined at 400 ° C for 4 hours to obtain a finished catalyst.

(Catalyst Preparation Example 2) Pellet-like titania having an average particle size of 5 mm and an average length of 6 mm was impregnated with a palladium nitrate solution so that Pd was 8 g per 1 liter thereof. After drying at 120 ℃ for 10 hours, at 400 ℃ 4
It was calcined for an hour to obtain a finished catalyst.

(Catalyst Preparation Example 3) Pelletized titania-zirconia (TiO 2) having an average particle diameter of 5 mm and an average length of 6 mm was used.
₂ : ZrO _{2 in} a weight ratio of 50:50, which is mainly composed of a composite oxide), and Ru per 1 liter thereof.
Was impregnated with a ruthenium nitrate solution so that the ratio was 8 g. After drying at 120 ° C. for 10 hours, it was calcined at 400 ° C. for 4 hours to obtain a finished catalyst.

(Catalyst Preparation Example 4) Pellets of zirconia having an average particle size of 5 mm and an average length of 6 mm were impregnated with an iridium chloride solution such that Ir was 3 g per 1 liter thereof. After drying at 120 ° C. for 10 hours, it was calcined at 400 ° C. for 4 hours to obtain a finished catalyst.

(Catalyst Preparation Example 5) Ferric nitrate and zirconyl nitrate were dissolved in water, and an aqueous titanyl sulfate sulfate solution was added and mixed well. Aqueous ammonia was added to this solution to adjust the pH to 9, and after aging for 24 hours, the formed precipitate was filtered and washed, and the obtained cake was dried at 120 ° C. overnight,
Further, it was baked at 700 ° C. The obtained solid is a powder containing iron, zirconium and titanium, and contains Fe ₂ O ₃ and ZrO.
Converted to the weight ratio of ₂ and TiO ₂ , Fe ₂ O ₃ : ZrO ₂ : TiO ₂ = 20: 40: 4 by analysis by the fluorescent X-ray method.
It was 0.

Starch was added to the powder thus obtained,
Further, an aqueous rhodium nitrate solution was added so that the rhodium atom would be 0.2% by weight with respect to the weight of the powder, and the mixture was mixed well,
It was molded into pellets having an average particle size of 5 mm and an average length of 6 mm, dried at 120 ° C. for 10 hours, and then calcined at 400 ° C. for 4 hours to obtain a finished catalyst.

Example 1 Waste water containing 2,800 mg / liter of ammonia nitrogen and 745 mg / liter of potassium bromide (500 mg / liter of bromine atom) was treated according to the wet oxidation treatment apparatus shown in FIG.
70 kg / cm ² G of the waste water is discharged by the constant volume pump 3 for increasing the pressure of the waste water.
The pressure was increased to, and the liquid was supplied into the apparatus at a flow rate of 2.5 l / hr corresponding to a liquid hourly space velocity = 5 hr ⁻¹ . Further, air was pressurized by the compressor 6 and then supplied at a flow rate corresponding to 1.05 times the theoretical oxygen demand. After heating this gas-liquid mixture in the heat exchanger 2, it is introduced into the wet oxidation tower 1 filled with 0.5 liter of the catalyst obtained in Catalyst Preparation Example 1, and the gas-liquid mixture is attached to the heater 9 attached to the wet oxidation tower 1. Was further heated and treated while being maintained at 250 ° C., the treated water was cooled in the heat exchanger 2 and introduced into the gas-liquid separator 5. In the gas-liquid separator 5, the liquid level controller (LC) detects the liquid level, the liquid level control valve 7 is operated to maintain a constant liquid level, and the pressure controller (PC) detects the pressure. Operate the pressure control valve 8 and pressure 70kg
/ Cm ² G was operated.

The concentration of ammonia nitrogen in the obtained treated water was 1 m according to the analysis by ion chromatography.
It was less than g / liter.

Comparative Example 1 An experiment was conducted under the same conditions as in Example 1 except that the wet oxidation tower 1 was not filled with a catalyst.

The concentration of ammoniacal nitrogen in the obtained treated water was determined by ion chromatography to be 2,
It was 700 mg / liter.

Example 2 Waste water containing 28,000 mg / liter of ammonia nitrogen and containing no halogen compound was treated according to the flow shown in FIG. First, 16 bromine atoms per 1 liter of the wastewater
Sodium bromide was added to a ratio of 0 mg.
The waste water containing sodium bromide was pressurized by the waste water pressurizing constant-pressure pump 3 and supplied into the apparatus at a flow rate of 1 liter / hr corresponding to a liquid space velocity = 2 hr ⁻¹ . Wet oxidation tower 1
Was charged with 0.5 liter of the catalyst obtained in Catalyst Preparation Example 2. The experiment was performed under the same conditions as in Example 1 except for the above. The air supply amount was 1.05 times the theoretical oxygen demand also here.

The concentration of ammonia nitrogen in the obtained treated water was 4 m according to the analysis by ion chromatography.
It was g / liter.

Comparative Example 2 An experiment was carried out under the same conditions as in Example 2 except that sodium bromide was not added to the wastewater.

The concentration of ammonia nitrogen in the obtained treated water was 12 according to the analysis by ion chromatography.
It was 0 mg / liter.

(Embodiment 3) According to the flow shown in FIG. 1, it contains 1,000 mg / liter of ammonia nitrogen (1,000 mg / liter of total nitrogen) and a plurality of kinds of organic compounds, and halogen compounds. The wastewater containing no water was treated. COD (Cr) of the wastewater is 20,
It was 000 mg / liter. 200 mg of bromine atom
Potassium bromate was added to the wastewater so that the amount became 1 / liter. The wet oxidation tower 1 was filled with 0.5 liter of the catalyst obtained in Catalyst Preparation Example 3. The amount of air supplied was 1.3 times the theoretical oxygen demand. The experiment was performed under the same conditions as in Example 1 except for the above.

The concentration of ammonia nitrogen in the obtained treated water was 1 m according to the analysis by ion chromatography.
It was less than g / liter. In addition, when bromide ion was quantified by ion chromatography, it was 200
It was mg / liter. COD (Cr) is 120mg
/ Liter.

Example 4 Waste water containing 20,000 mg / liter of ammonia nitrogen and containing no halogen compound was treated according to the flow shown in FIG. Sodium monobromoacetate (1.01 g) was added to 1 liter of waste water so that the bromine atom was in a ratio of 500 mg to 1 liter of the waste water. The wastewater containing this sodium monobromoacetate was supplied into the apparatus at a flow rate of 1 liter / hr corresponding to a liquid hourly space velocity = 2 hr ⁻¹ . The wet oxidation tower 1 was filled with 0.5 liter of the catalyst obtained in Catalyst Preparation Example 4. Treatment temperature is 230 ℃, pressure is 50kg /
It was set to cm ² G. The air supply rate is 1.
It was 1 time. The experiment was performed under the same conditions as in Example 1 except for the above.

The concentration of ammonia nitrogen in the obtained treated water was 5 mg according to the analysis by ion chromatography.
/ L, and COD (Cr) was 5 mg / L.

Example 5 A waste water containing 1,000 mg / liter of aniline and 745 mg / liter of potassium bromide (500 mg / liter of bromine atom) was treated with total nitrogen. The wet oxidation tower 1 was filled with 0.5 liter of the catalyst obtained in Catalyst Preparation Example 5. The amount of air supplied was 1.2 times the theoretical oxygen demand. The process was performed in the same manner as in Example 1 except for the above.

The concentration of ammonia nitrogen in the obtained treated water was 1 m according to the analysis by ion chromatography.
It was less than g / liter and COD (Cr) was 95 mg / liter.

(Example 6) Ammonia nitrogen 2,000
mg / liter, phenol 188 mg / liter and potassium bromide 745 mg / liter (50 by bromine atom)
Waste water containing 0 mg / l) was treated. The treatment temperature was 270 ° C. and the pressure was 85 kg / cm ² G here.
The amount of air supplied was 1.4 times the theoretical oxygen demand. The process was performed in the same manner as in Example 1 except for the above.

The concentration of ammonia nitrogen in the obtained treated water was 1 m according to the analysis by ion chromatography.
It was less than g / liter and COD (Cr) was 8 mg / liter.

Example 7 Waste water containing 500 mg / liter of urea and 4.47 g / liter of potassium bromide (3 g / liter of bromine atom) was treated with total nitrogen, and the treatment temperature was 200 ° C. and the pressure was 30 kg / liter. The treatment was carried out in the same manner as in Example 1 except that the supply amounts of cm ² G and air were twice the theoretical oxygen demand.

The concentration of ammonium nitrogen in the obtained treated water was 1 m according to the analysis by ion chromatography.
less than g / liter, COD (Cr) is 20 mg /
It was liter.

(Example 8) Ammonia nitrogen 2,800
A wastewater containing mg / liter and 745 mg / liter of potassium bromide (500 mg / liter of bromine atom) was treated. The treatment temperature was 170 ° C. and the pressure was 9 kg / cm ² G. The waste water was supplied into the apparatus at a flow rate of 1 liter / hr corresponding to liquid hourly space velocity = 2 hr ⁻¹ , and air was supplied at a flow rate corresponding to 5 times the theoretical oxygen demand. A treatment test was conducted under the same conditions as in Example 1 except for the above.

The concentration of ammonia nitrogen in the obtained treated water was 2 m according to the analysis by ion chromatography.
It was g / liter.

Example 9 Waste water containing 60,000 mg / l of hydrazine and containing no halogen compound was treated with total nitrogen according to the flow shown in FIG. The processing temperature was 150 ° C. and the pressure was 8 kg / cm ² G. Potassium bromide was added to the waste water so as to be 2.98 g / liter (2 g / liter in terms of bromine atom), and the potassium bromide-added waste water had a liquid hourly space velocity of 0.5 hr _−1.
Was supplied into the apparatus at a flow rate of 0.25 liter / hr. The air supply was set to 8 times the theoretical oxygen demand.
The process was performed in the same manner as in Example 1 except for the above.

The concentration of ammonia nitrogen in the obtained treated water was 40 according to analysis by ion chromatography.
The concentration of nitrogen as hydrazine was 1 mg / liter according to analysis by liquid chromatography.
It was less than 1 liter.

Example 10 Waste water containing 10,000 mg / liter of ammonia nitrogen and 500 mg / liter of nitrate nitrogen and containing no halogen compound was treated according to the flow shown in FIG. The wastewater 1
Potassium bromide was added so that the amount of bromine atom was 500 mg per liter. The wastewater containing this potassium bromide was supplied into the apparatus at a flow rate of 1.0 liter / hr corresponding to a liquid hourly space velocity = 2.0 hr ⁻¹ . The amount of air supplied was one time the theoretical oxygen demand. The process was performed in the same manner as in Example 1 except for the above.

The concentration of ammonia nitrogen in the obtained treated water was 10 according to the analysis by ion chromatography.
The concentration of mg / liter and nitrate nitrogen was 70 mg / liter according to the analysis by ion chromatography.

Example 11 According to the flow shown in FIG. 2, ammonium sulfate 13,200 mg / liter (ammonia nitrogen 2,800 mg / liter), potassium bromide 745 mg / liter (bromine atom 500 mg / liter) Was treated with wastewater. The wastewater was pressurized to 70 kg / cm ² G by the wastewater pressurizing constant-pressure pump 3, and was supplied into the apparatus at a flow rate of 2.5 liter / hr corresponding to liquid space velocity = 5 hr ⁻¹ . A 6 wt% sodium carbonate solution was fed into the apparatus by a constant pressure pump 10 for boosting the sodium carbonate solution at a flow rate 1.0 times the amount required to neutralize the sulfuric acid remaining after removal of the ammonia nitrogen. Further, air was pressurized by the compressor 6 and then supplied at a flow rate corresponding to 1.05 times the theoretical oxygen demand. After heating this gas-liquid mixture in the heat exchanger 2, it is introduced into the wet oxidation tower 1 filled with 0.5 liter of the catalyst obtained in Catalyst Preparation Example 1, and the gas-liquid mixture is attached to the heater 9 attached to the wet oxidation tower 1. Was further heated and treated while being maintained at 250 ° C., the treated water was cooled in the heat exchanger 2 and introduced into the gas-liquid separator 5. In the gas-liquid separator 5, the liquid level controller (L
The liquid level is detected by C), the liquid level control valve 7 is operated to maintain a constant liquid level, and the pressure controller (P
The pressure was detected by C) and the pressure control valve 8 was operated to operate so as to maintain the pressure of 70 kg / cm ² G.

The concentration of ammonia nitrogen in the obtained treated water was 1 m according to the analysis by ion chromatography.
It was less than g / liter.

Example 12 Waste water containing 28,000 mg / liter of ammonia nitrogen and containing no halogen compound was treated according to the flow shown in FIG. Chlorine atom is 710m for 1 liter of the wastewater.
Sodium chloride was added so that the ratio was g. The experiment was performed under the same conditions as in Example 2 except for the above.

The concentration of ammonium nitrogen in the obtained treated water was 20 according to analysis by ion chromatography.
It was mg / liter.

Example 13 Waste water containing 28,000 mg / l of ammonia nitrogen and containing no halogen compound was treated according to the flow shown in FIG. Iodine atom is 2.5 for 1 liter of the wastewater
Potassium iodide was added so that the ratio was 40 mg. The experiment was performed under the same conditions as in Example 2 except for the above.

The concentration of ammonia nitrogen in the obtained treated water was 30 according to the analysis by ion chromatography.
It was mg / liter.

[0085]

As described above in detail, according to the method for treating wastewater containing the nitrogen-containing compound of the present invention, the wastewater can be treated with extremely high efficiency as compared with the prior art. It is possible to operate the device at low temperature and low pressure.
Further, this can reduce the equipment cost, running cost, and the like, and thus can process the nitrogen-containing compound at a lower cost.

Further, the wastewater treatment method of the present invention is characterized in that the wastewater contains organic and / or organic substances as pollutants other than nitrogen-containing compounds.
Alternatively, even when an inorganic COD component or the like is contained, the COD component or the like can also be converted into water, carbon dioxide gas, an inorganic salt, ash, a lower molecular weight organic substance or the like to purify the wastewater. The wastewater treatment method of the present invention is thus a very excellent wastewater treatment method.

[Brief description of drawings]

FIG. 1 is one of the embodiments of the processing apparatus according to the present invention.

FIG. 2 is one of the embodiments of the processing apparatus according to the present invention.

[Explanation of symbols]

 1. Wet oxidation tower 2. Heat exchanger 3. Metering pump for boosting wastewater 4. Waste water tank 5. Gas-liquid separator 6. Compressor 7. Liquid level control valve 8. Pressure control valve 9. Heater 10. Metering pump for pressurizing sodium carbonate solution 11. Sodium carbonate solution tank

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B01J 23/46 301 B01J 23/46 301M 23/745 C02F 1/58 P C02F 1/58 ZABZ ZAB B01J 23/74 301M (72) Inventor Kiichiro Mitsui 1 992 Nishikioki, Kamahama, Aboshi-ku, Himeji-shi, Hyogo 1

Claims (3)

[Claims] 1. A wet oxidation treatment of wastewater containing a nitrogen-containing compound using a solid catalyst under the conditions of a temperature of 100 ° C. or more and less than 370 ° C. and a pressure condition in which the wastewater holds a liquid phase under the supply of an oxygen-containing gas. In doing so, a method for treating wastewater containing a nitrogen-containing compound, which comprises treating the wastewater in the presence of at least one halogen compound selected from the group consisting of chlorine compounds, bromine compounds and iodine compounds. 2. The method for treating wastewater containing a nitrogen-containing compound according to claim 1, wherein the halogen compound is a bromine compound. 3. The nitrogen according to claim 1, wherein the nitrogen-containing compound is at least one compound selected from the group consisting of ammonia, ammonium salts, hydrazine, hydrazinium salts, amine compounds, amide compounds and amino acid compounds. A method for treating wastewater containing compounds.