JPH11300374A - Treatment of waste water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly efficient novel method for treating waste water by which even a high-COD waste water is easily treated. SOLUTION: The waste water is heated under the pressure where the waste water is kept liq. and under the supply of an oxygen-contg. gas. In this case, the untreated oxidizable substance and/or the oxidizable substance formed by oxidation or decomposition are released into the waste gas, and the waste gas is separated from liq. under the conditions where the waste gas is rich in the oxidizable substance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to industrial plants such as chemical plants, electronic parts manufacturing equipment, food processing equipment, metal processing equipment, metal plating equipment, printing and plate making equipment, power generation equipment, and photo processing equipment. It is used to purify various wastewater such as wastewater, human waste, domestic wastewater such as sewage. Further, the present invention is used for reducing the treatment load of wastewater by discharging a large amount of oxidizable substances in exhaust gas, thereby improving the purification of wastewater and facilitating the operation of wastewater treatment. Is done. The present invention is also used for recovering organic compounds such as methane from wastewater.

[0002]

2. Description of the Related Art Conventionally, biological treatment, combustion, wet oxidation, and the like have been widely known as means for treating wastewater. In the biological treatment method, by-products such as excess sludge are generated, so that there is a problem in that the treatment is a problem, and there are many wastewaters that are difficult to treat in the biological treatment. The combustion method not only wastes resources because fossil fuel is burned as a fuel, but also has a problem such as an increase in carbon dioxide emission, which has recently been highlighted due to global warming.

On the other hand, the wet oxidation method which can purify wastewater by heat treatment under pressure does not have the above-mentioned problems and is very excellent. The oxidizable substance in the liquid was directly treated in a liquid. For this reason, when the substance is difficult to treat in the wastewater, it remains in the treatment liquid, and the purification property of the wastewater is reduced. Further, when the entire amount of the oxidizable substance in the wastewater is to be treated by the wastewater treatment device, the wastewater treatment device becomes excessively large, and the equipment cost rises. In particular, in methods such as the wet oxidation method in which the treatment temperature is controlled by the heat generated by oxidation or oxidative decomposition of wastewater, when the amount of oxidizable substances in the wastewater is large, the calorific value increases and the treatment temperature is controlled. Was difficult.

[0004] From the viewpoint of resource recycling, heat treatment of oxidizable substances in wastewater, even though it is waste, is never preferred. It is preferable to collect and recycle as useful a substance as possible.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method which can solve the above problems. That is, it is an object of the present invention to disperse oxidizable substances in wastewater into exhaust gas when the wastewater is treated, and to provide a novel wastewater treatment method capable of improving the purification property of wastewater. Another object of the present invention is to reduce harmful substances discharged to the environment by purifying oxidizable substances emitted into exhaust gas with high efficiency. In this case, a substance that has been difficult to treat by wastewater treatment is easily diffused into exhaust gas and purified to be treated as exhaust gas. Similarly, there is also a case where the oxidizable substances that have been diffused in the exhaust gas are collected and these substances are effectively used.

[0006] Further, it is an object of the present invention to provide a novel wastewater treatment method capable of performing a stable wastewater treatment operation even for wastewater containing a large amount of oxidizable substances in the wastewater, and having low equipment costs and wastewater treatment running costs. It is in.

[0007]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, have found that a method for heat-treating wastewater under a pressure at which the wastewater retains a liquid phase and an oxygen-containing gas supply is provided. The present inventors have found a new method for treating wastewater that emits oxidizable substances in exhaust gas, and have completed the present invention. The present invention provides an oxygen-containing gas to a wastewater to oxidize or decompose an oxidizable substance in the wastewater, and the oxidizable substance generated by the treatment of the oxidizable substance and / or untreated substance. The wastewater is treated by dispersing the oxidizable substance in exhaust gas. The oxidizable substances released into the exhaust gas are purified by processing using an exhaust gas treatment device, and / or by collecting organic substances such as methane from the exhaust gas, and
It can also recover resources.

Thus, the present invention provides a method for treating wastewater as described below.

(1) In a method of oxidizing or decomposing oxidizable substances in wastewater by heating the wastewater under a pressure at which the wastewater maintains a liquid phase and under the supply of an oxygen-containing gas, an untreated oxidized material is used. Wastewater, characterized in that oxidizable substances and / or oxidizable substances generated by oxidation or decomposition treatment are diffused into exhaust gas, and gas-liquid separation is performed under conditions where the exhaust gas contains a large amount of the oxidizable substance. Method.

(2) The method for treating wastewater according to (1), wherein the amount of the oxidizable substance contained in the exhaust gas is 10 ppm or more.

(3) The heating temperature of the wastewater is 100 to 370 ° C.
The method according to (1) or (2), wherein the temperature at the time of gas-liquid separation is 35 ° C. or more.

(4) The supply amount of the oxygen-containing gas is less than the theoretical oxygen demand of the oxidizable substance in the wastewater.
The method for treating wastewater according to any one of (3).

(5) The effluent is heated by manganese, cobalt, nickel, copper, cerium, silver, platinum, palladium,
The method for treating wastewater according to any one of (1) to (4), wherein the method is performed in the presence of a solid catalyst containing at least one selected from the group consisting of rhodium, gold, iridium, and ruthenium.

(6) The COD concentration of the waste water is 10 to 300 g.
The method for treating wastewater according to any one of (1) to (5), wherein the wastewater is water / liter.

(7) The ratio of the amount of liquid at the maximum temperature during heating to the amount of water is in the range of 90 to 30%.
(6) The method for treating wastewater according to any of (6).

(8) The method for treating wastewater according to any one of (1) to (7), further comprising recovering an oxidizable substance contained in the exhaust gas.

(9) The method for treating wastewater according to any one of (1) to (7), wherein the exhaust gas is further purified using an exhaust gas treatment device.

(10) The method according to any one of (1) to (9), wherein the treatment liquid after gas-liquid separation is further subjected to a heat treatment under a pressure at which the treatment liquid retains a liquid phase and under the supply of an oxygen-containing gas. Wastewater treatment method.

(11) The method for treating wastewater according to any one of (1) to (10), wherein the wastewater is wastewater containing acetic acid and / or formic acid.

(12) The method for treating wastewater according to any one of (1) to (10), wherein the wastewater is ammonia-containing wastewater.

(13) The method for treating wastewater according to any one of (1) to (3) and (5) to (10), wherein the wastewater is benzene-containing wastewater.

Hereinafter, the present invention will be described in detail.

[0023]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for heat-treating wastewater while supplying oxygen-containing gas under a pressure at which the wastewater maintains a liquid phase. This is a new wastewater treatment method that can enhance the water quality. Specifically, when heating the wastewater, an oxygen-containing gas is supplied to oxidize or decompose the oxidizable substance in the wastewater, and the oxidizable substance generated by the treatment and / or the untreated The oxidizable substance is diffused in the exhaust gas. Then, gas-liquid separation is performed under the condition that the exhaust gas contains a large amount of the oxidizable substance. As described above, the oxidizable substance is removed by accompanying the exhaust gas, thereby improving the purification property of the wastewater. That is, in the wastewater treatment method according to the present invention, the exhaust gas discharged from the wastewater treatment device is a gas containing a large amount of oxidizable substances. The oxidizable substance includes not only the oxidizable substance originally contained in the wastewater but also the oxidizable substance generated by performing the wastewater treatment. When the oxidizable substance in the wastewater is oxidized using an oxygen-containing gas, components such as carbon dioxide and water are generated when the oxidizable substance is completely processed. However, the processing is rarely performed completely. And in a state of oxidizable substance different from the substance that was present in the original wastewater that has not been completely oxidized,
A part often remains. Therefore, in the wastewater treatment method according to the present invention, these oxidizable substances are diffused from the liquid into the exhaust gas.

In the present invention, the oxidizable substance is a substance such as various organic substances and inorganic COD components, and includes ammonia, hydrazine, hydrogen sulfide and the like.

In the present invention, the oxidation treatment or the decomposition treatment means, for example, an oxidation treatment for converting ethanol into acetic acid,
Oxidative decomposition treatment to convert acetic acid to carbon dioxide and water, decarboxylation decomposition treatment to convert acetic acid to carbon dioxide and methane, decomposition treatment to reduce the molecular weight of various organic substances by heat, and hydrolysis of urea to ammonia and carbon dioxide by heat It refers to various treatments such as a decomposition treatment, an oxidative decomposition treatment of converting ammonia or hydrazine into nitrogen gas and water, and in the present invention, may be simply described as a heat treatment.

In the present invention, the oxidizable substance in the wastewater is
The heat treatment often decomposes a substance having a relatively high molecular weight, which was originally present in the wastewater, into a substance having a low molecular weight. Then, it is often converted to a substance having a low boiling point, and is more easily diffused into the exhaust gas than the oxidizable substance in the original wastewater.

In the present invention, the reaction of the oxidation treatment or the decomposition treatment includes a reaction that does not necessarily require an oxygen-containing gas. However, in the method for treating wastewater according to the present invention, it is effective to supply an oxygen-containing gas even when such a reaction is mainly performed. By supplying the oxygen-containing gas, the purifying property of the wastewater is higher than when no oxygen-containing gas is supplied. For this reason, in the present invention, the expression “oxidation treatment” may be used to include all reactions of oxidation treatment or decomposition treatment.

The treatment temperature of the waste water of the present invention is 100 to 37.
There is no particular limitation as long as it is 0 ° C, but preferably 140 to 3
The temperature is 00 ° C, more preferably 150 to 280 ° C. When the temperature exceeds 370 ° C., the liquid cannot maintain a liquid phase. On the other hand, when the temperature is lower than 100 ° C., the processing performance is significantly reduced. When the temperature exceeds 300 ° C., the pressure for maintaining the liquid phase is very high,
The equipment costs and running costs for this are high. Also, when the temperature is lower than 140 ° C., the treatment performance is generally low and the purification of waste water is often low.

In the method of the present invention, the wastewater is treated under heating conditions. The treatment pressure is not particularly limited as long as the wastewater retains a liquid phase, and is appropriately selected depending on the correlation with the treatment temperature. Is done. However, effectively, the processing pressure is a pressure that maintains the liquid phase, but a pressure that is not so high. That is, it is effective that the ratio of the liquid amount at the highest temperature during heating to the liquid amount of the original wastewater is in the range of 90 to 30%. As described above, when the amount of liquid during heating is reduced with respect to the original wastewater, the oxidizable substance in the liquid is easily diffused into the gas, and the effect of the present invention is enhanced. It is more preferably 87% to 50%, and even more effectively 84%.
~ 55%. When the content is 90% or more, the effect is small, and when the content is less than 30%, the liquid is excessively concentrated and the purification property of the wastewater treatment is reduced, and problems such as salt precipitation and scale adhesion occur. Increase. The liquid amount at the maximum temperature during the heating can be substantially calculated from the supply liquid amount, the supply gas amount, the temperature, the pressure, and the like. That is, it is a liquid amount obtained by subtracting the amount of evaporated water under the conditions (supply gas amount, temperature, pressure) from the supplied liquid amount. When the wastewater is subjected to heat treatment, the amount of the liquid is usually the lowest when the temperature is the highest.

In the present invention, the amount of the oxidizable substance diffused in the exhaust gas is not particularly limited. However, the amount of the oxidizable substance is effectively 10 ppm or more, more effectively 50 ppm or more, and even more effectively 100 ppm or more. When the amount is less than 10 ppm, it is often the case that the conventional method can sufficiently treat the wastewater with high purification performance even if the method is not the method of the present invention.

In the present invention, the temperature at the time of gas-liquid separation for separating the exhaust gas and the processing liquid is not particularly limited, but it is effective that the temperature is 35 ° C. or more. The higher the temperature at the time of gas-liquid separation, the higher the amount of oxidizable substances emitted in the exhaust gas, the smaller the amount of oxidizable substances remaining in the processing liquid, and the higher the effect of the present invention. It becomes. Therefore, it is more effective that the temperature is 50 ° C. or more,
It is more effective that the temperature is at least ° C. Therefore, when it is necessary to lower the temperature of the processing liquid for post-processing or the like, it is effective to cool the processing liquid after gas-liquid separation. In the present invention, the treatment liquid refers to a liquid obtained by subjecting waste water to heat treatment.

Conventionally, when heating wastewater,
After the pressure is released from the wastewater treatment device and discharged, the treatment liquid and the exhaust gas are often subjected to gas-liquid separation treatment. However, in this case, the mixture of the processing liquid and the exhaust gas is often cooled using a heat exchanger before the pressure is released. For this reason, it is effective to preferably perform gas-liquid separation before decompression and discharge the exhaust gas without lowering the temperature of the exhaust gas. The method of gas-liquid separation in this case may be provided with a gas-liquid separator or gas-liquid separation in a reaction tower, and is not particularly limited.

In the present invention, in the case where the mixture of the treatment liquid and the exhaust gas is decompressed and discharged from the wastewater treatment apparatus and then gas-liquid separated, it is not particularly limited. It is more effective not to attach it, and it is more effective not to lower the temperature so much even if there is a cooler.

In the present invention, it is effective that the supply amount of the oxygen-containing gas is less than the theoretical oxygen demand of the oxidizable substance in the wastewater. Here, the theoretical oxygen demand of the oxidizable substance means the amount of oxygen necessary to decompose the oxidizable substance into ash such as nitrogen, carbon dioxide, water and / or sulfate. In the present invention, when the wastewater is heat-treated at less than the theoretical oxygen demand, that is, when the wastewater is heat-treated with an insufficient amount of oxygen, the amount of the oxidizable substance emitted in the exhaust gas can be particularly increased. . When the supply amount of the oxygen-containing gas is large and the oxygen amount is sufficient, most of the oxidizable substances are often completely oxidized. In addition, most of the remaining oxidizable substances also become organic acid compounds mainly containing acetic acid, and are hardly scattered in the exhaust gas. On the other hand, when oxygen is insufficient, organic substances are particularly easily decomposed into relatively low-boiling organic substances, carbon monoxide, and the like, and are easily released into exhaust gas. Also, when a carboxylic acid compound such as acetic acid is originally contained in wastewater or generated by wastewater treatment, the carboxylic acid compound is liable to cause a decarboxylation reaction.For example, in the case of acetic acid, carbon dioxide and methane gas are generated. It is easy to do. Therefore, when the wastewater is heated under the supply of an oxygen-containing gas, organic substances having 2 or more carbon atoms often generate acetic acid. However, the present invention decomposes acetic acid due to insufficient oxygen, resulting in oxidation. It facilitates the emission of toxic substances.

Specifically, it is effective that the amount is 0.1 to 0.95 times the theoretical oxygen demand of the oxidizable substance in the wastewater. Further, it is more effective that the amount is 0.2 times or more and 0.9 times or less. When the supply amount of the oxygen-containing gas is less than 0.1 times, only a small amount of the oxidizable substance in the wastewater can be oxidized, so that the amount of the oxidizable substance scattered in the exhaust gas decreases, and the wastewater is discharged. Often, the purifying properties are also reduced. If the ratio exceeds 0.95 times, much of the oxidizable substance in the wastewater is oxidized, so that the amount of the oxidizable substance scattered in the exhaust gas is reduced, and the effect of the present invention is reduced. There are many.

However, when most of the oxidizable substances contained in the wastewater and the oxidizable substances generated by the oxidizing treatment of the oxidizable substances are substances which are not released into the exhaust gas, the oxygen-containing gas It is effective that the supply amount is not less than the theoretical oxygen demand of the oxidizable substance. Specific examples of such an oxidizable substance include a sulfur compound. Sulfur compounds such as sulfides, thiosulfate ions and sulfite ions do not dissipate in exhaust gas. Therefore, it is effective that these substances are completely oxidized as wastewater. Examples of the wastewater in which such a sulfur compound occupies most of the oxidizable substances contained in the wastewater include wastewater from ethylene production equipment and rayon production equipment. Generally, wastewater mainly containing such sulfur compounds is
In many cases, it is difficult to purify organic substances contained in the wastewater by oxidizing wastewater. Therefore, in many cases, it is effective to treat the sulfur compound under the supply of an oxygen-containing gas capable of completely oxidatively decomposing. In such a case, the larger the amount of supplied gas, the greater the amount of organic substances to be released, and the higher the purification efficiency of the wastewater. Therefore,
It is effective that the supply amount of the oxygen-containing gas in the wastewater mainly containing these sulfur compounds is not less than the theoretical oxygen demand of the oxidizable substance in the wastewater. In particular,
It is effective that the theoretical oxygen demand of the oxidizable substance in the wastewater is 1.1 times or more and 3.0 times or less. Further, it is more effective that the ratio is 1.2 times or more and 2.5 times or less. In the present invention, the theoretical oxygen demand of the oxidizable substance in the wastewater is difficult to obtain in actual wastewater, so the chemical oxygen demand of the oxidizable substance in the wastewater (C
OD (Cr)) or the total oxygen demand (TOD). This is because the theoretical oxygen demand of the oxidizable substance in the wastewater is almost equal to the chemical oxygen demand or the total oxygen demand of the oxidizable substance in the wastewater in many cases.

Although the present invention is not particularly limited, it is effective to use various solid catalysts used in an aqueous solution under heating conditions. The use of a solid catalyst can further enhance the purification of waste water. In addition, when a solid catalyst is used, the decomposability of the decomposable substance in the wastewater is improved, and the amount of the oxidizable substance diffused in the exhaust gas increases. Further, since the processing temperature can be reduced as compared with the case where no catalyst is used, the processing conditions can be made milder, and the equipment cost and running cost can be reduced. The type of the solid catalyst is not particularly limited, for example, manganese, cobalt, nickel, copper, cerium,
It is effective that the solid catalyst contains at least one selected from the group consisting of silver, platinum, palladium, rhodium, gold, iridium, and ruthenium. These amounts are not particularly limited, but may be 0.05 to 25 in the solid catalyst.
Preferably it is a percentage by weight. The solid catalyst preferably contains at least one selected from titanium, zirconium, aluminum, silicon, iron, activated carbon, and the like, in addition to the above metals. The shape of the solid catalyst is effectively at least one selected from pellet, spherical, granular, ring, and honeycomb shapes, but is not particularly limited.

In the present invention, the heat treatment using a solid catalyst and the heat treatment without using a solid catalyst can be combined, and the treatment is not particularly limited. The solid catalyst can be treated using several types. In such a case, the processing temperature and the supply amount of the oxygen-containing gas may be arbitrarily changed in various processes, and are not particularly limited.

In the present invention, the COD concentration of the wastewater is not particularly limited, but the case where the COD concentration is 10 to 300 g / liter is effective. Also, more effectively 20-250g
Per liter, and more effectively 30 to 200 g /
Liters. When the concentration of COD exceeds 300 g / liter, the heat of oxidation of COD becomes extremely large, so that it is difficult to control the treatment apparatus. When the concentration is less than 10 g / liter, the wastewater is drained using the method of the present invention. The effect of processing is small, and processing using other conventional techniques is more effective. However, according to the present invention, wastewater having a considerably high COD concentration can be treated as compared with a conventional method for completely oxidizing oxidizable substances in wastewater. This is because even if the calorific value becomes large in the conventional method of completely treating wastewater, the calorific value can be reduced with the method of the present invention. Further, the calorific value, that is, the treatment temperature can be controlled by the supplied oxygen amount, and the method of the present invention is suitable for high COD wastewater treatment.

In the present invention, the pH of the waste water and the treatment liquid is not particularly limited, and can be widely applied from acids to alkalis. However, when a large amount of an organic acid compound such as acetic acid is present in the waste water and the treatment liquid, the p
Effectively, H is neutral to acidic. By doing so, the emission of the organic acid compound into the exhaust gas is facilitated. Conversely, when a large amount of basic compounds such as ammonia, pyridine, and aniline are present in the waste water and the treatment liquid, it is effective that the pH of the liquid is neutral to alkaline. This facilitates the diffusion of the basic compound into the exhaust gas.

The oxygen-containing gas according to the present invention is a gas containing oxygen molecules and / or ozone. When a gas such as ozone or oxygen is used, it may be appropriately diluted with an inert gas or the like. it can. In addition, oxygen-enriched gases can be used, and in addition to these gases, oxygen-containing exhaust gas generated from other plants can also be used as appropriate. Most preferred, however, is inexpensive air.

The space velocity of the waste water in the process according to the present invention, the reaction column per 0.1hr ^-1 ~10hr ^-1 is effective. When the space velocity is less than 0.1 hr ^-1 , the amount of wastewater to be treated is reduced, and the equipment becomes excessively large.
If it exceeds ^-1 , the effect of the present invention is undesirably reduced. Also preferably, it is 0.3 hr ^{-1 to 5} hr ^-1 .

In the method for treating wastewater according to the present invention, various methods can be employed for supplying wastewater and an oxygen-containing gas. For example, a cocurrent method in which both wastewater and an oxygen-containing gas are supplied from the lower part of the reaction tower, a cocurrent method in which both the wastewater and the oxygen-containing gas are supplied from the upper part of the reaction tower, and the wastewater forms a continuous liquid phase. Counter-current method, in which the oxygen-containing gas is supplied from the top of the reaction tower and
There is a countercurrent method in which wastewater is supplied from the upper part of the reaction tower, and oxygen-containing gas is supplied from the lower part of the reaction tower so as to form a continuous phase of the gas. Although any of these methods can be adopted, an effective method is the following method. The method described above is the most commonly employed method when treating wastewater under heating, and it is easy to control the apparatus and the effect of the present invention is high. The other method is also highly effective in the present invention, and is particularly effective when there is a large amount of oxidizable substances which easily dissipate in the original wastewater. The other method is also highly effective in the present invention, and is particularly effective when there is a large amount of oxidizable substances which easily dissipate in the original wastewater.
The present invention may be implemented by variously combining these methods, and is not particularly limited.

In the reaction tower of the present invention, in addition to the solid catalysts described above, packing and various internal crops for improving gas-liquid stirring and contact efficiency and reducing gas-liquid drift are provided. Etc. can be incorporated.

When a metal or ceramic filler is used as the filler, its shape is not particularly limited as long as it has no problem in terms of wear resistance and strength. Typical examples thereof include a granular filler such as a sphere, a pellet, a lump, a ring, a saddle, and a polyhedron. In addition, a filler in the form of a continuous body such as a fiber, a chain, a bead, or a mesh can also be used. Among them, spherical, pellet, ring or saddle-shaped fillers, particularly spherical, pellet or ring-shaped fillers are preferably used. In addition,
Granular packing is also preferable in that it can be easily packed in a reaction tower. Examples of these are Raschig rings,
Absorption towers and distillation towers such as slotted rings, Leschig rings, Dixon packings, Heli packs, McMahon packings, Helixes, Cannon packings, Pole rings, Coil packs, Berl saddles, Interlocks saddles, Bur saddles, Good low packings, Demisters etc. Metal or ceramic packings commonly used in gas-liquid contactors can be used.

Further, as the internal crop, one or a plurality of wire meshes, single-hole or perforated plates, grids, partition plates and the like can be appropriately provided, and there is no particular limitation.

The exhaust gas discharged when the waste water of the present invention is subjected to the heat treatment can recover organic substances such as methane and useful resources such as ammonia from the exhaust gas. The recovery method in this case is not particularly limited, and may be an adsorption method,
Various methods such as a distillation method can be adopted.

Further, the exhaust gas discharged when the waste water of the present invention is subjected to the heat treatment and the exhaust gas after the above-mentioned useful resources are collected (hereinafter, may be simply referred to as the exhaust gas) are purified using an exhaust gas treatment apparatus. can do. Further, gas generated from a drainage tank or another process can be treated using the exhaust gas treatment device.

Various exhaust gas treatment devices can be used as the exhaust gas treatment device. Further, a catalyst can be used in this exhaust gas treatment device. The catalyst is not particularly limited, but an oxide containing at least one selected from the group consisting of titanium, zirconium, silicon, aluminum, cerium, and iron as a catalyst A component, and platinum, palladium as a catalyst B component, It is effective to contain at least one metal or oxide selected from the group consisting of rhodium, ruthenium, iridium, vanadium, tungsten, molybdenum, chromium, manganese, and copper. Exhaust gas can also be heated in various types of heat exchangers before treating the exhaust gas,
It is effective that the treatment temperature is in the range of 150 to 700 ° C, more effectively 200 to 500 ° C.
The space velocity of the gas is not particularly limited,
It may be appropriately selected, but 1000 h ⁻¹ or more and 100,000
it is effective that at h ^-1 or less, it is more effective at 5000h ^-1 or more 50000h ^-1 or less. In the exhaust gas treatment, an oxygen-containing gas can be appropriately supplied, and the supply method is not particularly limited.
In the present invention, the expression “exhaust gas treatment” may be used, including the exhaust gas purification process and the exhaust gas recovery process.

In the present invention, the treatment liquid is not particularly limited so as to be subjected to any post-treatment or to be discharged as it is. However, when the supply amount of the oxygen-containing gas is less than the theoretical oxygen demand of the oxidizable substance in the wastewater, the oxidizable substance often remains in the treatment liquid. Therefore, particularly in this case, it is preferable to perform some post-treatment on the treatment liquid.

When the COD concentration of the treatment liquid is relatively high, heat treatment is performed at a treatment temperature of 100 to 370 ° C. under a pressure at which the treatment liquid maintains a liquid phase while supplying an oxygen-containing gas. Is effective. In this case, it is effective to use a solid catalyst as described above. The treatment liquid obtained by this treatment (hereinafter sometimes simply referred to as treatment liquid) often has very high purification performance. In addition, the post-processing may be performed once after the processing according to the present invention is performed, and then the pressure is released again, and then the pressure is again increased and separately performed, or the processing according to the present invention and the post-processing are connected by a line. However, the treatment may be performed continuously, and is not particularly limited. These treatments may have different treatment conditions such as treatment temperature, treatment pressure, amount of supplied oxygen-containing gas, and pH of the solution. However, in this case, it is effective that the amount of supplied oxygen-containing gas is not less than the theoretical amount of oxygen required for the oxidizable substance contained in the processing liquid. In the case where the treatment is performed by connecting with a line, a gas-liquid separator, an exhaust gas discharge line, a pressure control valve, an oxygen-containing gas supply line, a heat exchanger, and the like can be appropriately provided in the middle of the connection. .

In the treatment liquid according to the present invention, the oxidizable substance in the waste water is subjected to heat treatment, and the residue contains a relatively large amount of an organic acid compound. Therefore, biological treatment of these treatment liquids
It can often be done very easily. Therefore, the treatment liquid in which the treatment according to the present invention has been performed is then separated and recovered from the treatment liquid with the organic acid compound remaining in the treatment liquid, or the treatment liquid is subjected to biological treatment, or both. Implementation is effective. In order to separate and recover the organic acid compound from the processing solution, it is effective to perform an extraction and / or distillation operation, and there is no particular limitation. Further, the method of biologically treating the treatment liquid and the method of biologically treating the remaining liquid obtained by recovering the organic acid compound from the treatment liquid are not particularly limited. For example, various treatment methods such as a method of purifying with an aerobic treatment, a method of purifying with an anaerobic treatment, and a method of treating both anaerobic and aerobic treatments in combination can be adopted. From the viewpoint of resource recovery, it is effective to recover methane by anaerobic methane fermentation.

The wastewater to be treated according to the present invention is discharged from various industrial plants such as chemical plants, electronic component manufacturing equipment, food processing equipment, metal processing equipment, metal plating equipment, printing and plate making equipment, power generation equipment, and photographic processing equipment. Various wastewaters, such as wastewater, human waste, and domestic wastewater such as sewage, may be mentioned, but the wastewater that can be treated in the present invention is not limited to these. However, the wastewater is effectively a benzene-containing wastewater discharged from an ethylene production facility or the like, and is composed of an aliphatic carboxylic acid, an aliphatic carboxylic acid ester, an aromatic carboxylic acid, an aromatic carboxylic acid ester,
Acetate and / or formic acid-containing wastewater discharged from production facilities such as OGs and alcohols, and ammonia discharged from production facilities for organic nitrogen compounds such as nitriles, amines and amides, power generation facilities, and electronic component production facilities Contains wastewater.

When the wastewater is wastewater discharged from an ethylene production facility or the like, aromatic compounds such as benzene contained in the wastewater have been difficult to treat by heat treatment of the wastewater. Therefore, it is effective to disperse an aromatic compound such as benzene in the exhaust gas and treat the exhaust gas by the method of the present invention.

Further, wastewater is used for producing an aliphatic carboxylic acid or an aliphatic carboxylic acid ester such as acrylic acid, acrylic acid ester, methacrylic acid or methacrylic acid ester, an aromatic carboxylic acid or aromatic carboxylic acid such as terephthalic acid or terephthalic acid ester. In the case of wastewater containing acetic acid and / or formic acid discharged from an acid ester production facility, an EOG production facility, or an alcohol production facility such as methanol, ethanol, and higher alcohols, the wastewater may contain a relatively large amount of lower organic substances. Many. Also, these wastewaters often have high COD concentrations. Therefore, it is effective to disperse carboxylic acids such as acetic acid and formic acid, aldehydes such as formaldehyde and acetaldehyde, and alcohols such as methanol and ethanol in the exhaust gas and treat the exhaust gas by the method of the present invention.
Further, the wastewater also generates a large amount of gas such as methane, ethane, and carbon monoxide generated by decarboxylation of acetic acid and the like, so that the effect of the present invention is high.

Ammonia-containing wastewater is discharged from facilities for producing organic nitrogen compounds such as acrylonitrile, acrylamide, aniline, caprolactam, power plants such as thermal power plants and nuclear power plants, and facilities for producing electronic components such as semiconductor factories. In the case of wastewater, nitrogen compounds such as ammonia contained in the wastewater may be more easily and inexpensively treated by exhaust gas treatment than by heat treatment of the wastewater. Therefore, it is effective to disperse nitrogen compounds such as ammonia in the exhaust gas and treat the exhaust gas in the method of the present invention.

[0057]

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

Example 1 Using the apparatus shown in FIG. 1, the treatment was performed under the following conditions.

The reaction column 1 used for the treatment had a diameter of 26 m.
m, cylindrical shape having a length of 3000 mm. Reaction tower 1
Was filled with 0.8 liter of a catalyst containing titania and palladium as main components and a palladium content of 0.5% by weight. The wastewater subjected to the treatment was wastewater discharged from an aromatic carboxylic acid and aromatic carboxylic acid ester production facility, and was a wastewater containing a large amount of alcohol, aldehyde, and carboxylic acid compounds. The wastewater had a COD (Cr) of 74 g / liter and a pH of 2.5.

The treatment method is as follows. The wastewater sent from the wastewater supply line 6 is supplied to the wastewater supply pump 5 at 1.6 liter / liter.
h, that is, the space velocity per catalyst amount (hereinafter, L
After increasing the pressure at 2 hr ^-1 ,
The mixture was heated to 250 ° C. by the heater 3 and supplied from the bottom of the reaction tower 1. After air is supplied from the oxygen-containing gas supply line 10 and pressurized by the compressor 9, O ₂ / COD (C
r) (Amount of oxygen in supply gas / Chemical oxygen demand of wastewater)
= Oxygen-containing gas flow control valve 1 so that the ratio becomes 0.8
In step 1, the flow rate was controlled and supplied from just before the heater 3 and mixed into the wastewater. In the reaction tower 1, 2
The temperature was maintained at 50 ° C. to carry out the treatment. The treated liquid was subjected to gas-liquid separation by a gas-liquid separator 13 via a treatment liquid line 12.
In the gas-liquid separator 13, a liquid level controller (LC)
, The liquid level control valve 15 was controlled so as to maintain a constant liquid level, and the processing liquid was cooled to 28 ° C. by the cooler 4 and then discharged from the liquid level control valve 15. The pressure control valve 14 detects pressure by a pressure controller (PC),
Control was performed so as to maintain a pressure of 0 kg / cm ² G. The exhaust gas was separated into gas and liquid at about 250 ° C., and the gas exhaust line was heated so that the temperature of the gas exhaust line 16 became 250 ° C. or higher. The ratio of the liquid amount at the highest temperature during heating to the liquid amount of the original waste water was about 70%.

The obtained processing solution was COD (Cr) 4.2
g / liter, pH 4.2. Further, as a result of measuring the gas discharged from the gas discharge line 16 with a total hydrocarbon concentration measuring device (THC meter), the hydrocarbon concentration was about 13000 ppm.

(Comparative Example 1) The apparatus shown in FIG. 2 was used, the processing pressure was set to 95 kg / cm ² G, the mixture of the exhaust gas and the processing liquid was sufficiently cooled, followed by gas-liquid separation, and the exhaust gas and the processing liquid were separately separated. The treatment was carried out under the same conditions as in Example 1 except that the oxidizable substance was not so diffused in the exhaust gas after discharging. The temperature when the mixture of the exhaust gas and the processing liquid was subjected to gas-liquid separation was 25 ° C. The ratio of the liquid amount at the highest temperature during heating to the liquid amount of the original waste water was about 92%.

The obtained processing solution was COD (Cr) 15.
It was 5 g / liter and pH 3.8.

(Example 2) Using an apparatus having a reaction tower of the same size as that of Example 1 shown in FIG. 2, treatment was performed under the following conditions.

The inside of the reaction tower 1 was filled with 0.8 liter of Raschig ring made of SUS. The wastewater used for treatment is the wastewater discharged from a chemical plant, and contains 8 parts of benzene.
The wastewater contained 8 mg / liter. CO in wastewater
D (Cr) was 31 g / liter and pH was 13.5.

In the treatment, the wastewater is fed at a pressure of 0.4 liter / h, the treatment temperature is 190 ° C., and the treatment pressure is 18 kg / c.
m ² G. The air is O ₂ / COD (Cr) = 0.
Supplied at a rate of 95. The ratio of the liquid amount at the highest temperature during heating to the liquid amount of the original waste water was about 85%. The temperature when the mixture of the exhaust gas and the processing liquid was subjected to gas-liquid separation was 92 ° C.

The obtained processing solution does not contain benzene (less than 1 mg / liter) and has a COD (Cr) of 1.1 g / liter.
Liters, pH 12.8. The benzene concentration in the exhaust gas was about 300 ppm, and the hydrocarbon concentration was about 4200 ppm.

(Comparative Example 2) The temperature at which the mixture of the exhaust gas and the treatment liquid was subjected to gas-liquid separation was set at 25 ° C, and the treatment pressure was set at 50 kg / cm ² G at the maximum temperature during heating with respect to the original wastewater liquid amount. Except that the liquid volume ratio was about 98%
The same processing as in Example 2 was performed.

The obtained processing solution contained benzene at 63 mg /
Liter, COD (Cr) 1.6g / liter,
pH was 12.8.

(Example 3) Using an apparatus having a reaction tower of the same size as that of Example 1 shown in FIG. 3, treatment was carried out under the following conditions.

The reactor 1 was charged with 0.8 liter of a catalyst containing titania and platinum as main components and having a platinum content of 0.5% by weight. The wastewater subjected to the treatment was wastewater discharged from an organic nitrogen compound production facility, and was wastewater containing 5.4 g / liter of ammonia. C in drainage
The OD (Cr) was 46 g / liter and the pH was 8.2.

The method of treatment is as follows. The waste water sent from the waste water supply line 6 is supplied to the waste water supply pump 5 at 0.8 liter / liter.
h, that is, the space velocity per catalyst amount (hereinafter, L
After the pressurized feed at ¹ hr ^-1 ,
The mixture was heated to 260 ° C. by the heater 3, supplied to the gas-liquid separator 13, and further supplied from the upper portion of the reaction tower 1. A 25% by weight aqueous solution of sodium hydroxide is supplied to an alkali supply line 8.
It was supplied at a flow rate of 0.12 liter / h from just before the heater 3 using the alkali supply pump 7.
Air is supplied from an oxygen-containing gas supply line 10 and is pressurized by a compressor 9 and then O ₂ /COD(Cr)=0.7.
The flow rate was controlled by the oxygen-containing gas flow rate control valve 11 so that the ratio became as follows. In the reaction tower 1,
The temperature was maintained at 260 ° C. using the electric heater 2 to perform the treatment. In the gas-liquid separator 13, the liquid level is detected by a liquid level controller (LC), and the liquid level control valve 15 is controlled so as to maintain a constant liquid level.
After cooling to ° C., the liquid was discharged from the liquid level control valve 15. That is, the treatment liquid was discharged from the bottom of the reaction tower 1. The pressure control valve 14 detects pressure by a pressure controller (PC),
Control was performed so as to maintain a pressure of 70 kg / cm ² G.
The exhaust gas is separated into gas and liquid at about 260 ° C,
The gas discharge line was heated so that the temperature was 260 ° C. or higher. The ratio of the liquid amount at the highest temperature during heating to the liquid amount of the original waste water was about 85%.

The obtained processing solution does not contain ammonia, nitrite ions and nitrate ions (less than 1 mg / l), 6.8 g / l COD (Cr), pH 10.
It was 3. The ammonia concentration in the exhaust gas is about 20
000 ppm.

(Comparative Example 3) Using the apparatus shown in FIG. 4, wastewater and an aqueous solution of sodium hydroxide were also supplied from the bottom of the reaction tower 1, and the temperature when the mixture of the exhaust gas and the processing liquid was subjected to gas-liquid separation was set at 25. The same processing as in Example 3 was performed except that the temperature was changed to ° C.

The obtained processing solution contained 4.7 g of ammonia.
/ L and 0.7 g / L of nitrate ions, COD (Cr) 17 g / L, pH 11.2.

Example 4 Using the apparatus shown in FIG. 6, the same SUS Raschig ring as in Example 2 was filled, and the same waste water as in Example 2 was treated under the following conditions.

The method of treatment is as follows. After the wastewater at 35 ° C. sent from the wastewater supply line 6 is pressure-fed by the wastewater supply pump 5 at a flow rate of 0.4 liter / h, the gas-liquid separator 1
3 and further from the top of the reaction tower 1. Air is supplied from an oxygen-containing gas supply line 10 and pressurized by a compressor 9, and then the reaction is performed by controlling the flow rate of the oxygen-containing gas flow control valve 11 so that the ratio of O _{2 /} COD (Cr) becomes 0.95. Feed from the bottom of column 1. In the reaction tower 1, the temperature was kept at 190 ° C. using the electric heater 2 to perform the treatment. In the gas-liquid separator 13, the liquid level controller (L
The liquid level was detected by C), the liquid level control valve 15 was controlled so as to maintain a constant liquid level, and the processing liquid was cooled to 25 ° C. by the cooler 4 and then discharged from the liquid level control valve 15. That is, the treatment liquid was discharged from the bottom of the reaction tower 1. Pressure control valve 1
4 is a pressure controller (PC) that detects pressure and 18
The pressure was controlled so as to maintain a pressure of kg / cm ² G. The exhaust gas was gas-liquid separated at about 35 ° C. so that the temperature of the gas discharge line 16 was 35 ° C. or higher. The ratio of the liquid amount at the highest temperature during heating to the liquid amount of the original waste water was about 87%.

The obtained processing solution does not contain benzene (less than 1 mg / liter) and has a COD (Cr) of 1.2 g / liter.
Liters, pH 12.8. The benzene concentration in the exhaust gas was about 300 ppm, and the hydrocarbon concentration was about 3400 ppm.

(Comparative Example 4) Using an apparatus having a reaction tower of the same size as that of Example 2 shown in FIG. 6, the temperature of the wastewater sent from the wastewater supply line was set to 15 ° C. When the temperature is 15 ° C. and the temperature of the gas exhaust line 16 is 1
The same processing as in Example 2 was performed except that the temperature was changed to 5 ° C.

The obtained processing solution contains 4 mg / l of benzene, 1.5 g / l of COD (Cr), p
H12.8.

Example 5 A gas-liquid mixture after the treatment shown in FIG. 8 was decompressed at the same time, and a gas-liquid separation device was used after decompression.
The same SUS Raschig ring was packed in a reaction tower of the same size as in Example 2, and waste water discharged from an ethylene production facility was treated under the following conditions.

The wastewater subjected to the treatment was prepared by converting sodium sulfide to C
Mainly contained as OD component, 45 mg / l of benzene as organic matter, COD (Cr) is 28%
g / l and pH 13.8.

In the treatment, the wastewater was pressurized and fed at a rate of 0.2 l / h, the treatment temperature was 165 ° C., and the treatment pressure was 9 kg / cm.
Was ² G. The air is O ₂ /COD(Cr)=2.0
Was supplied so as to have a ratio of The ratio of the liquid amount at the highest temperature during heating to the liquid amount of the original waste water was about 66%.
After depressurizing the mixture of the exhaust gas and the treatment liquid, the mixture was subjected to gas-liquid separation, and the temperature at this time was 65 ° C.

The resulting processing solution contained no benzene (less than 1 mg / liter), and had a COD (Cr) of 1.4 g / liter.
Liter, pH 13.2. The benzene concentration in the exhaust gas was about 70 ppm.

Comparative Example 5 The same treatment as in Example 5 was carried out except that the mixture of the exhaust gas and the treatment liquid was decompressed and then subjected to gas-liquid separation, and the temperature at this time was set to 15 ° C.

The obtained processing solution contained benzene at 11 mg /
Contained liters.

(Embodiment 6) A reaction tower having the same size as that of Embodiment 1 shown in FIG. 5 is provided. In Embodiment 1, the processing liquid in the cooled reaction tower 1 is not cooled, and the processing liquid discharge line 17 is post-processed. The reaction was carried out under the following conditions so that it could be directly supplied to the reaction tower 18.

The inside of the reaction tower 1 was filled with 0.8 liter of a catalyst containing titania and ruthenium as main components and having a ruthenium content of 1.0% by weight.
0.8 liter of a catalyst containing titania and platinum as main components and having a platinum content of 0.5% by weight was filled. The wastewater subjected to the treatment was wastewater discharged from an aliphatic carboxylic acid and aliphatic carboxylic acid ester production facility, and was a wastewater containing a large amount of aldehyde and carboxylic acid compounds. The wastewater had a COD (Cr) of 68 g / liter and a pH of 3.2.

In the treatment, the wastewater was pressurized and fed at a rate of 1.6 L / h, and the treatment temperature in the reaction tower 1 was set at 260 ° C. and the treatment pressure was set at 65 kg / cm ² G. In the reaction tower 1, air was supplied at a ratio of O ₂ /COD(Cr)=0.6. Then, a mixture of the exhaust gas and the processing liquid was subjected to gas-liquid separation at about 260 ° C. The ratio of the liquid amount at the maximum temperature during heating to the liquid amount of the original waste water was about 72%. The processing liquid discharged from the liquid level control valve 15 was supplied directly to the reaction tower 18 without cooling. In addition, the processing liquid at this time was partially sampled and analyzed, and the result of the analysis was 12.9 g / L of COD (Cr). The processing liquid discharged from the liquid level control valve 15 is supplied with O ₂ / COD based on the COD (Cr) concentration of the original waste water.
It was mixed before the reaction tower 18 so that the ratio of (Cr) = 0.2. That is, O _{2 /} COD (Cr) for the treatment liquid discharged from the liquid level control valve 15 was 1.05. The processing temperature in the reaction tower 18 is 260 ° C., and the processing pressure is 64.
kg / cm ² G. The treatment liquid treated in the reaction tower 18 was cooled by the cooler 4, and after gas-liquid separation, the exhaust gas and the treatment liquid were discharged.

The obtained processing solution was COD (Cr) 320
mg / liter, pH 4.9. In addition, the reaction tower 1
Was about 22000 ppm in the exhaust gas discharged from.

(Comparative Example 6) Using an apparatus having a reaction tower of the same size as that of Example 6 shown in FIG.
No gas-liquid separator and no oxygen-containing gas supply part were provided between the two, and the exhaust gas and the processing liquid discharged from the reaction tower 1 were supplied to the reaction tower 18 as they were. In the reaction tower 1, the same processing as in Example 6 was performed, except that air was supplied at a ratio of O ₂ /COD(Cr)=0.8. The processing pressure of the reaction tower 18 was 65 kg / cm ² G.

[0092] The obtained processing solution was COD (Cr) 15 g.
/ Liter, pH 4.3.

(Example 7) The exhaust gas discharged in Example 1 and air were separately sent to an exhaust gas treatment apparatus, and the temperature of the inlet of the apparatus was set to 3
The treatment was performed at 20 ° C. and SV = 20,000 h ⁻¹ . The exhaust gas treatment device was filled with a catalyst having alumina and platinum as main components on a cordierite honeycomb carrier.

The gas treated by the exhaust gas treatment device was measured by a total hydrocarbon concentration measuring device (THC meter), and as a result, was less than 10 ppm of hydrocarbon.

Example 8 The exhaust gas discharged in Example 2 and air were separately sent to an exhaust gas treatment device, and the same treatment as in Example 7 was performed.

As a result of measuring the gas treated by the exhaust gas treatment device with a gas chromatograph and a THC meter, benzene was not detected (less than 1 ppm) and the amount of hydrocarbons was 1 ppm.
It was less than 0 ppm.

(Embodiment 9) Exhaust gas discharged in Embodiment 3 and air are separately sent to an exhaust gas treatment device, and the temperature at the inlet of the device is set to 3
The treatment was performed at 50 ° C. and SV = 5000 h ⁻¹ . The exhaust gas treatment device was filled with a catalyst in which palladium was supported on a honeycomb formed body mainly composed of oxides of titanium, silicon, vanadium, and tungsten.

As a result of measuring the gas treated by the exhaust gas treatment device with a gas chromatograph and a THC meter, no ammonia was detected (less than 1 ppm) and the amount of hydrocarbon was less than 10 ppm.

(Example 10) Exhaust gas discharged in Example 5 and air were separately sent to an exhaust gas treatment apparatus, and treated in the same manner as in Example 7.

As a result of measuring the gas treated by the exhaust gas treatment device with a gas chromatograph, no benzene was detected (less than 1 ppm).

(Example 11) Exhaust gas discharged from the reaction tower 1 of Example 6 and air were separately sent to an exhaust gas treatment apparatus, and treatment was performed in the same manner as in Example 7.

As a result of measuring the gas treated by the exhaust gas treatment device with a THC meter, it was found to be less than 10 ppm of hydrocarbon.

[0103]

According to the method of the present invention, the oxidizable substance in the waste water is subjected to a heat treatment, and the substance produced by the heat treatment of the oxidizable substance and / or the residual oxidizable substance is removed from the exhaust gas. Can be dissipated inside. Thereby, the amount of the oxidizable substance remaining in the treatment liquid can be reduced, and the purifying property of the wastewater can be improved. The exhaust gas that is discharged is
Organic substances such as methane and ammonia can be recovered from the exhaust gas. As a result, there are effects such as reduction in cost and effective use of resources. The exhaust gas discharged can be purified using an exhaust gas treatment device, and the amount of harmful oxidizable substances discharged can be greatly reduced. That is, in comparison with the conventional method in which oxidizable substances in wastewater are completely oxidized in the wastewater treatment apparatus, the present invention provides a method for removing oxidizable substances with the same wastewater treatment equipment and wastewater treatment conditions. It can be significantly purified. In particular, when the substance remaining in the treatment liquid and the exhaust gas is difficult to treat in the wastewater treatment facility and the wastewater treatment conditions, and the substance is relatively easily diffused into the exhaust gas, the effect of the present invention is extremely high. Things.

Further, the present invention can easily treat wastewater having a high COD concentration as compared with the conventional method in which oxidizable substances in wastewater are completely oxidized in a wastewater treatment device. In the conventional method, it is difficult to treat wastewater having a high COD concentration in terms of control of the apparatus, equipment costs, and running costs. In particular, when the wastewater having a high COD concentration is treated only by the wastewater treatment device, the amount of generated heat is extremely large, and it is difficult to control the wastewater treatment device. But,
Since the present invention treats a part of the oxidizable substance with the exhaust gas, it can be treated relatively easily.

When the supply amount of the oxygen-containing gas is less than the theoretical amount of oxygen required for the oxidizable substance in the wastewater, the temperature can be controlled by controlling the supply amount of oxygen. This facilitates temperature control.

When the oxidizable substance in the wastewater is supplied with less than the theoretical oxygen demand, the COD concentration of the treatment liquid is often relatively high. In this case, by performing the heat treatment under a pressure at which the processing liquid keeps a liquid phase under the supply of the oxygen-containing gas, a processing liquid having a very high purifying property can be obtained easily and inexpensively.

Further, according to the present invention, even if the processing conditions such as the processing temperature and the processing time are changed, the purification performance of the wastewater does not change so much, and the operation surface of the processing can be simplified.

The present invention also compares the conventional method for completely oxidizing oxidizable substances in wastewater,
The processing conditions can be made mild, and the processing equipment cost and the processing running cost can be reduced.

In the treatment liquid after the treatment according to the present invention, the oxidizable substance in the waste water is subjected to heat treatment, and the residue contains a relatively large amount of organic acid compounds. For this reason, biological treatment of these treatment liquids can often be performed very easily. In addition, methane is produced by biological treatment such as anaerobic methane fermentation, such as recovering organic acid compounds from the treatment liquid,
It is also relatively easy to recover resources from wastewater.
In addition, wastewater that was originally difficult to treat biologically can be converted into a liquid that can be easily treated biologically, and is excellent in terms of improving the purification of wastewater.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a processing apparatus according to the present invention.

FIG. 2 is an embodiment of a processing apparatus according to the present invention.

FIG. 3 is an embodiment of a processing apparatus according to the present invention.

FIG. 4 is an embodiment of a processing apparatus according to a comparative example of the present invention.

FIG. 5 is an embodiment of a processing apparatus according to the present invention.

FIG. 6 shows an embodiment of a processing apparatus according to the present invention.

FIG. 7 shows an embodiment of a processing apparatus according to the present invention.

FIG. 8 shows an embodiment of a processing apparatus according to the present invention.

[Explanation of symbols]

 1. Reaction tower 2. Electric heater 3. Heater 4 Cooler 5. Drainage supply pump 6. 6. Wastewater supply line 7. Alkaline supply pump 8. Alkaline supply line Compressor 10. Oxygen-containing gas supply line 11. Oxygen-containing gas flow control valve 12. Processing liquid line 13. Gas-liquid separator 14. Pressure control valve 15. Liquid level control valve 16. Gas discharge line 17. Processing liquid discharge line 18. Reaction tower

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C02F 1/58 C02F 1/58 A (72) Inventor Yukihiro Yoneda 992 Koishihama, Nishioki, Aboshi-ku, Himeji-shi, Hyogo 1 Nippon Shokubai Co., Ltd.

Claims (13)

[Claims] 1. A method for heating a waste water under an oxygen-containing gas supply under a pressure at which the waste water retains a liquid phase to oxidize or decompose oxidizable substances in the waste water. A method for treating wastewater, comprising: dispersing a substance and / or an oxidizable substance generated by an oxidation treatment or a decomposition treatment into an exhaust gas, and performing gas-liquid separation under a condition where the exhaust gas contains a large amount of the oxidizable substance. . 2. The method according to claim 1, wherein the amount of the oxidizable substance contained in the exhaust gas is 10 ppm or more. 3. The method for treating wastewater according to claim 1, wherein the heating temperature of the wastewater is 100 to 370 ° C., and the temperature at the time of gas-liquid separation is 35 ° C. or more. 4. The wastewater treatment method according to claim 1, wherein the supply amount of the oxygen-containing gas is less than the theoretical oxygen demand of the oxidizable substance in the wastewater. 5. The method for heating waste water in the presence of a solid catalyst containing at least one selected from the group consisting of manganese, cobalt, nickel, copper, cerium, silver, platinum, palladium, rhodium, gold, iridium and ruthenium. The method for treating wastewater according to any one of claims 1 to 4, wherein the method is performed. 6. The method for treating wastewater according to claim 1, wherein the COD concentration of the wastewater is 10 to 300 g / liter. 7. The ratio of the liquid amount at the maximum temperature during heating to the liquid amount of the waste water is in the range of 90 to 30%.
The method for treating wastewater according to any one of the above. 8. The method for treating wastewater according to claim 1, further comprising recovering an oxidizable substance contained in the exhaust gas. 9. The method for treating wastewater according to claim 1, wherein the exhaust gas is further purified by using an exhaust gas treatment device. 10. The wastewater treatment according to claim 1, wherein the treatment liquid after the gas-liquid separation is further subjected to a heat treatment under a pressure at which the treatment liquid maintains a liquid phase and under a supply of an oxygen-containing gas. Method. 11. The method for treating wastewater according to claim 1, wherein the wastewater is wastewater containing acetic acid and / or formic acid. 12. The method for treating wastewater according to claim 1, wherein the wastewater is ammonia-containing wastewater. 13. The wastewater according to claim 1, wherein the wastewater is benzene-containing wastewater.
The method for treating wastewater according to any one of to 3 to 5 and 10.