JPH06277681A - Waste water treatment process - Google Patents

Abstract

PURPOSE:To reduce odor by using the catalyst wet oxidization process for processing treated gas from the gas-liquid separation in a system for providing filtrate by wet oxidizing, gas-liquid separating and solid-liquid separating the waste water in the specified high temperature Zone under the supply of a gas containing oxygen. CONSTITUTION:In treating treated water containing particularly high chemical oxygen demand amount (COD) exhausted from a chemical plant, a plating industrial equipment or the like and fed from a waste water supply line 8, the waste water is mixed with air pressurized by a compressor 5, and then its temperature is raised by a heat exchanger 2 and then guided into a wet oxidizing reaction column 1 from below. The waste water is set oxidized under the high temperature of 140-370 deg.C in the column. Then the liquid to be treated is cooled in the heat exchanger 2 and guided into a gas-liquid separator 4 to separate the exhaust gas, and the treated liquid is fed from a solid-liquid separation device 14, and filtrate passed through the device is mixed with the exhaust gas after gas-liquid separation, and then the mixture is passed through a heat exchanger 19, guided into a catalytic wet oxidizing reaction column 18 and exhausted after the catalytic wet oxidization.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a chemical plant facility, a plating industry facility, a leather manufacturing facility, a metal industrial facility, a metal mining facility, a food manufacturing facility, a pharmaceutical manufacturing facility, a textile industrial facility,
Paper and pulp industry equipment, dyeing dye industry equipment, electronic industry equipment,
The present invention relates to a method for purifying wastewater discharged from machinery industry equipment, printing platemaking equipment, glass manufacturing equipment, and the like. More specifically, it relates to a treatment method for purifying wastewater having a high chemical oxygen demand (hereinafter also referred to as COD) and containing substances such as heavy metals, aluminum, phosphorus, silicon, calcium and magnesium. .

[0002]

2. Description of the Related Art Conventionally, a cleaning method effective for reducing COD of waste water, a cleaning method for removing nitrogen, phosphorus, etc. contained in the waste water, a cleaning method for removing heavy metals contained in the waste water, or a combination thereof has been provided. Various purification methods such as a purification method have been studied. For example, biological treatment method, combustion method, dry method of heating and evaporation, oxidation method using chlorine-based chemicals,
Electrolytic oxidation method, hydrogen peroxide-ferrous iron method, ozone oxidation method,
Flocculation separation removal method by adding inorganic or organic flocculant,
Adsorption separation and removal methods using activated carbon, inorganic adsorbents or organic polymer materials, reverse osmosis methods using membranes, electrodialysis methods and ultrafiltration methods have been implemented or proposed.

[0003]

When the above-mentioned methods are used, there are many problems as described below, and any of the methods needs improvement. For example, (1) biological treatment method, coagulation separation removal method, adsorption separation removal method, electrodialysis method, reverse osmosis membrane method, ultrafiltration method, hydrogen peroxide-ferrous salt method, ozone oxidation method, etc. However, it is difficult to carry out purification treatment to a sufficient level by themselves. (2) The combustion method, the dry solidification method, the electrolytic oxidation method, the ozone oxidation method, the adsorption separation removal method, the reverse osmosis membrane method, the electrodialysis method, the ultrafiltration method, etc. have high processing costs. (3) The combustion method, the dry solidification method, the coagulation separation removal method, the adsorption separation removal method, and the like had a problem of generation of a substance which causes secondary pollution after treatment.

In view of the above circumstances, the present inventors have researched a novel wastewater treatment technique which does not have the above-mentioned drawbacks, and have developed the following method. First, by performing wet oxidation treatment under high temperature and high pressure, mainly heavy metals etc. in the wastewater are insolubilized or hardly dissolved, and the generated solid matter is removed by solid-liquid separation,
By subjecting the filtrate to the catalytic wet oxidation treatment again, mainly COD components in the wastewater are oxidatively decomposed.

By this method, it is possible to highly purify the wastewater with almost no generation of substances that cause secondary pollution, and it is possible to operate at a relatively low cost.
Various effects such as good maintenance of the equipment were obtained.

[0006] Further researches have further shown that a non-catalytic wet oxidation step, a solid-liquid separation step, and a catalytic wet oxidation step are sequentially connected by a pipeline, and each device is operated continuously under high pressure. It was found that the method is simpler in equipment than the conventional wet oxidation treatment method. It is also advantageous in terms of equipment cost and operation cost.

However, even when this method is adopted, the oxygen-containing exhaust gas after the non-catalytic wet oxidation treatment is discarded without being reused. Therefore, it has been recognized that there is a problem in terms of equipment costs such as a compressor, and also in terms of environment because exhaust gas after non-catalytic wet oxidation treatment has a slight odor.

The present invention has been made in view of such circumstances, and provides a more effective wet oxidation treatment method by eliminating the above-mentioned facility cost and environmental inconvenience. To do.

[0009]

[Means for Solving the Problems] As a result of earnest research to solve the above problems, it is achieved by using exhaust gas after non-catalytic wet oxidation treatment for catalytic wet oxidation treatment. Provided is a method for treating wastewater, which facilitates the operation for carrying out the process and is excellent in practicality and economy. The details are specified as follows.

(1) (1) The wastewater is subjected to a non-catalytic wet oxidation treatment at a temperature of 140 ° C. to 370 ° C. under a pressure such that the wastewater holds a liquid phase, while supplying a gas containing oxygen to the wastewater, 2) Next, the primary treatment exhaust gas is separated by gas-liquid separation treatment, (3) the solid-containing treatment wastewater obtained by the primary treatment is subjected to solid-liquid separation treatment, (4) the filtrate after the solid-liquid separation treatment, 140 ℃ ~
In the method of performing catalytic wet oxidation treatment at a temperature of 370 ° C. and under a pressure at which the filtrate retains a liquid phase, a method for treating wastewater, characterized in that primary treatment exhaust gas is supplied to a catalytic wet oxidation step to perform catalytic wet oxidation treatment. .

(2) Each step of non-catalytic wet oxidation treatment, gas-liquid separation treatment, solid-liquid separation treatment and catalytic wet oxidation treatment is sequentially connected by a pipeline, and each step is continuously operated under high pressure. The wastewater treatment method described.

(3) The above 1 or 2, wherein the total amount of at least one kind of heavy metals, aluminum, phosphorus, silicon, calcium or magnesium is 1 mg (hereinafter also referred to as "mg / liter") or more in 1 liter of the waste water. Wastewater treatment method.

Further, in the above treatment method, the catalytic wet oxidation treatment may be performed by using the primary treatment exhaust gas and another gas containing oxygen in combination.

Furthermore, the primary treatment exhaust gas can be supplied to the catalytic wet oxidation treatment step without cooling.

In the present invention, when treating wastewater, the wastewater is supplied at 140 ° C. to 37 ° C. under the supply of a gas containing oxygen.
The first step is the wet oxidation treatment at a temperature of 0 ° C. and a pressure at which the wastewater maintains a liquid phase. By this first step, substances harmful to the catalytic wet oxidation treatment of aluminum, phosphorus, silicon, calcium, magnesium and the like (hereinafter also referred to as harmful substances) or heavy metals in the wastewater are converted into oxides, hydroxides and inorganics. It is converted to a water-insoluble or sparingly water-soluble substance such as a salt or other compound, or is adsorbed and precipitated by a substance that is deposited as a water-insoluble or sparingly soluble compound by this treatment. Thereafter, the non-catalyst wet oxidation treatment liquid is subjected to a gas-liquid separation treatment (hereinafter also referred to as the second step), and the non-catalyst wet oxidation treatment liquid further removes solid matter such as a precipitate or a suspension from the liquid. By performing solid-liquid separation and removal (hereinafter also referred to as the third step), harmful substances and heavy metals can be removed. Further, in the present invention, the third step outlet liquid (hereinafter also referred to as a filtrate) is subjected to a catalyst wet process in the presence of an oxygen-containing gas at a temperature of 140 ° C. to 370 ° C. and a pressure at which the filtrate holds a liquid phase. The fourth step of oxidation treatment is adopted.

The adoption of this fourth step is the main factor that makes the treatment method of the present invention an excellent purification method for wastewater as compared with conventional treatment methods. The first to the first in the present invention
By adopting the third step, the cause of clogging of the wet oxidation reactor or deterioration of the catalyst due to adsorption of harmful substances or heavy metals on the catalyst used in the fourth step or generation of scale is excluded. It is a thing.

Further, in the present invention, by using the primary treatment exhaust gas containing oxygen generated in the second step as the oxygen-containing gas for the fourth step, the components such as odor of the exhaust gas generated in the first step are further increased. The amount of oxygen-containing gas required for the entire apparatus is reduced because the catalyst is decomposed and the exhaust gas can be purified, and oxygen is effectively used.

For this reason, for example, when air is used after being pressurized by a compressor or the like and supplied, the capacity of the compressor is small, which is advantageous in terms of cost and deodorization such as odor problem. In terms of countermeasures, it is possible to solve easily without the need to add special equipment.

Further, in the present invention, the oxygen required in the fourth step is also supplied in the first step, so that the oxygen amount in the first step increases as a result. In the present invention, the non-catalytic wet oxidation treatment is adopted in the first step. Generally, in the non-catalytic wet oxidation treatment, the treatment efficiency of the present invention tends to be improved as the amount of oxygen increases, so that the treatment method of the present invention is superior to the conventional method.

Further, in the present invention, the catalytic wet oxidation treatment is adopted in the fourth step. In general, the larger the amount of oxygen is, the more preferable even in the catalytic wet oxidation treatment. Unlike the non-catalytic wet oxidation treatment, this catalytic wet oxidation treatment does not always improve the treatment efficiency and the like as the amount of oxygen increases, and there may be an optimum oxygen amount for the catalytic wet oxidation treatment. Further, in the catalytic wet oxidation treatment, if the amount of oxygen supplied is the same, the gas other than oxygen increases, and the stirring efficiency of the gas-liquid in the catalytic reaction column and the like tend to improve, thereby increasing the treatment efficiency and the like. Therefore, the treatment method of the present invention is superior to the conventional method.

Further, in the present invention, the amount of heavy metals or harmful substances to be removed is large, or due to other reasons, the concentration of heavy metals or harmful substances to be removed is sufficient even after the third step. If not reduced,
Prior to the first step, it is possible to remove the heavy metals and harmful substances by a conventional purification method such as activated carbon, an adsorption separation method using an inorganic adsorbent or an organic polymer material, and an electrodialysis method. it can. Similarly, after performing the third step, it is possible to further remove heavy metals and harmful substances by using a conventional method for purifying heavy metals and harmful substances.

At the same time, the treatment of the first step in the present invention
Other pollutants in this wastewater, such as organic substances and inorganic COD components, are also oxidized and oxidatively decomposed to be converted into lower molecular weight organic substances, inorganic salts, carbon dioxide gas, water and ash, etc. It can be partly purified.

Therefore, in the case where heavy metals, harmful substances, etc. form compounds with the organic substances in the wastewater and dissolve in the wastewater, the present invention can also decompose the organic substances in the wastewater at the same time. Therefore, it is very effective in removing heavy metals and harmful substances from wastewater. That is, when heavy metals and harmful substances are dissolved in wastewater as a chelate complex, for example, the chelating agent is decomposed by this treatment, and heavy metals and harmful substances are released in the form of ions and the like. To be done. For this reason, heavy metals, harmful substances, and the like are deposited as insoluble or sparingly soluble compounds in water, tend to become solids, and are easily removed.

Further, the solid content after solid-liquid separation and removal has a remarkably small amount of organic matter, particularly high molecular weight organic matter, as compared with coagulation separation removal method, adsorption separation removal method, etc. Subsequent treatment of solids is also easy.

In the fourth step, the catalyst wet oxidation treatment is carried out using a catalyst to oxidize and oxidatively decompose the organic matter and the inorganic COD component, and lower molecular weight organic matter, inorganic salt, carbon dioxide gas, nitrogen gas, water and ash content. The wastewater is remarkably purified by switching to the above.

The wastewater purified by the treatment method of the present invention can be discharged directly or subjected to biological treatment or chemical treatment as a post-treatment. Even in this case, heavy metals and harmful substances are removed from the wastewater in advance, and COD
The components, etc. are considerably reduced, and the residual COD components, etc. are decomposed into substances that are very easily decomposed in biological treatment and chemical treatment, so the burden on biological treatment equipment or chemical treatment equipment is extremely high. Becomes smaller.

Further, in the present invention, since the site is small and the apparatus is compact, the treatment equipment is compared with the conventional wastewater treatment equipment such as biological treatment equipment and combustion treatment equipment. Is small, the treatment process is simplified, and it is advantageous in terms of capital investment and running cost.

The harmful substance according to the present invention is at least one selected from the group consisting of aluminum, phosphorus, silicon, magnesium and calcium. Examples of heavy metals include cadmium, nickel, cobalt, manganese, copper and zinc, At least one selected from silver, iron, chromium, tin, lead, mercury, arsenic, bismuth, thallium, antimony, molybdenum, tungsten and the like. The state is not particularly limited,
For example, it is an element ion or complex ion of the above various metals, an organometallic compound, or the like. The most effective of these heavy metals are lead, cadmium, nickel, cobalt, mercury,
Iron, copper, zinc, chromium, manganese, and silver.

The concentration of heavy metals or harmful substances in the wastewater treated in the present invention is not particularly limited as long as the total of these is 1 mg / liter or more, but 10 mg / liter to 100 g in the wastewater. It is effective when the amount is contained in 100 μg / liter, and more effective is 100 mg / liter to 50 g / liter.
If it exceeds 100 g / liter, the solubility of the oxygen-containing gas in the waste water is drastically reduced and the reaction is hindered. Further, if the content of these is 1 mg / liter or more, the prima facie effect of the present invention occurs, but 100 mg / liter
When the amount is less than liter, which is relatively small, it can be treated using other treatment methods, and the merit of the treatment method of the present invention is reduced.

The concentration of COD in the wastewater is effective when it is contained in the range of 1 g / liter to 200 g / liter, and more effective is 5 g / liter to 150 g.
g / liter. When the concentration of COD exceeds 200 g / liter, the heat of oxidation of COD becomes extremely large, which makes it difficult to control the processing apparatus. If it is less than 1 g / liter, the heat of oxidation of COD is small, and in such a case, even if a heat exchange device is used as an auxiliary equipment to recover heat, it becomes difficult to independently operate the wet oxidation treatment device by this heat. It is a thing. In such a case, there is no problem in the wet oxidation itself, but when performing the treatment, a separate heat supply device is required, which is relatively disadvantageous in terms of energy consumption.

As the non-catalytic wet oxidation treatment apparatus and the catalytic wet oxidation treatment apparatus used in the present invention, those usually used are used, and the wet oxidation reaction tower is of a single-tube type or a multi-tube type. May be, the ingredients contained in the wastewater,
Depending on the amount, the single-tube type and the multi-tube type can be used alone or in combination to separately treat the components contained in the wastewater under conditions suitable for the treatment.

The non-catalytic wet oxidation treatment described here means
The wet oxidation treatment is not particularly limited in the wet oxidation treatment reaction tower without being filled with the catalyst described below, but the treatment is generally performed using a hollow wet oxidation reaction tower. It is also possible to fill the wet oxidation reaction tower with a filler such as metal or ceramic to improve stirring of liquid and gas.

The catalyst described herein may be any catalyst as long as it is a solid catalyst and has both activity and durability under the conditions of liquid phase oxidation, such as titanium and iron. , A catalyst containing aluminum, silicon, zirconium, activated carbon, or the like, and preferably an oxide such as titanium, titanium-zirconium, or titanium-iron is used. These catalysts may contain a second component in addition to the above components (hereinafter referred to as the first component).

The second component is at least one metal such as manganese, cobalt, nickel, tungsten, copper, cerium, silver, platinum, palladium, rhodium, gold, iridium or ruthenium, or a component thereof. Can be used. This catalyst is the first
For the component 75 to 99.95% by weight, the second component 25 to
The ratio is preferably 0.05% by weight. In addition, various shapes of the catalyst can be adopted and are not particularly limited.

Further, in the treatment method of the present invention, the catalyst wet oxidation treatment is carried out after solid-liquid separation and removal of the treatment liquid after the catalyst-free wet oxidation treatment. At this time, in the catalyst wet oxidation treatment, an adsorption tower filled with an inorganic adsorbent may be provided in front of the catalyst wet oxidation reaction tower to further prevent poisoning of the catalyst due to heavy metals and harmful substances not sufficiently removed. . The inorganic adsorbent is not particularly limited, but is preferably an oxide containing titanium such as titanium, titanium-zirconium, or titanium-iron.

The treatment temperature of the non-catalytic wet oxidation treatment or the treatment temperature of the catalytic wet oxidation treatment of the present invention is 140 ° C. to 370.
℃, preferably 180 ℃ ~ 300 ℃. Three
When the temperature is 70 ° C. or higher, the liquid cannot hold the liquid phase. If the temperature is lower than 140 ° C., the treatment efficiency will decrease.

The treatment amount of the waste water of the non-catalytic wet oxidation treatment can be increased when the treatment temperature is high, and conversely becomes small when the treatment temperature is low. As is generally the space velocity is 0.1hr ~ ¹ ~5hr ~ ¹ is effective, more effective is 0.5hr ~ ¹ ~3hr ~ ^1. If exceeding 5 hr ~ ¹ decreases processing efficiency is not preferable because if it is less than 0.1 hr ~ ¹ to decrease the amount of processing waste water facility becomes excessive.

Further, if the COD treatment efficiency in the non-catalytic wet oxidation treatment is increased more than necessary, the temperature will be maintained in the next treatment, the catalytic wet oxidation treatment, and the heat source for self-sustaining operation will be insufficient. Therefore, in the non-catalytic wet oxidation treatment, the solid matter and the suspension produced by the wet oxidation treatment are sufficiently precipitated, and the COD treatment efficiency is such that they can be sufficiently separated and removed after the non-catalytic wet oxidation treatment. It is preferable to suppress The treatment efficiency of COD in this non-catalytic wet oxidation treatment is not particularly limited and may be appropriately selected depending on the case, but is generally 20% to 80%.

In the catalytic wet oxidation treatment, the amount of the filtrate which has been subjected to the solid-liquid separation treatment after the non-catalytic wet oxidation treatment is generally the same as that in the non-catalytic wet oxidation treatment, and the space velocity is generally
0.1 hr ~ ¹ to ⁵ hr ~ ¹ is effective, and more effectively 0.5 hr ~ ¹ to ³ hr ~ ¹ . Space velocity 5 hr ~ ¹
If it exceeds, the processing efficiency will decrease and the space velocity will be 0.1h.
This is because if it is less than r ~ ¹ , the amount of treatment decreases and the equipment becomes too large.

The oxygen-containing gas used in the first step in the present invention means a gas containing oxygen or ozone.
When a gas such as ozone or oxygen is used, it can be appropriately diluted with an inert gas or the like before use. Air is preferably used, but in addition to these gases, oxygen-containing waste gas generated from other plants can be appropriately used.

The oxygen-containing gas used in the fourth step is
Although it is the exhaust gas generated in the first step, when the oxygen amount is insufficient, the oxygen-containing gas may be appropriately mixed and used. On the contrary, when the amount of oxygen is too large or the amount of gas is too large to hold the liquid phase, a part of the exhaust gas generated in the first step is appropriately discharged and only the remaining exhaust gas is used as the oxygen-containing gas in the fourth step. Can also be used as In addition,
This control can be appropriately performed by a control valve, a gas flow controller, or the like.

The amount of oxygen-containing gas used in this first step is
It can be appropriately selected depending on the concentration of wastewater. In this case, the COD component of the wastewater is completely converted to water, carbon dioxide gas, inorganic salt,
0.5 times to 5 times the amount of oxygen required to make ash, etc.,
It is more preferably 1 to 3 times. If it exceeds 5 times, useless oxygen is supplied, and if it is less than 0.5 times, the amount of oxygen required is insufficient and the purification of waste water becomes incomplete. Further, the range of 0.5 times to 1 time is not sufficient as the amount of oxygen required to completely convert the COD component of waste water into water, carbon dioxide gas, inorganic salts, and other ash content. The reason for this is that the processing efficiency of COD is usually less than 100%, so the supplied oxygen is not used 100% in the end, and in such a case the amount of oxygen supplied should be adjusted to 1 times the actual processing efficiency. This is because the COD processing efficiency does not change so much even if the COD is reduced to less than 100%.

Further, in the case of the fourth step, since the exhaust gas after the wet oxidation treatment in the first step is used, it is effective that the oxygen concentration is 3% by volume or more in terms of the gas concentration excluding water vapor, and more effective. This is the case when the oxygen concentration is 5 to 30% by volume. This is because when the oxygen concentration is less than 3% by volume, the catalytic wet oxidation treatment becomes a rate-determining dissolution of oxygen in the liquid, resulting in incomplete purification of wastewater. Therefore, when the amount of oxygen in the fourth step is insufficient, it is possible to appropriately mix the oxygen-containing gas with the exhaust gas to increase the amount of oxygen for treatment.

In the present invention, the gas-liquid separation treatment (second step) is carried out after the first step to separate the oxygen-containing gas used in the fourth step and the primary treatment liquid containing the solid matter.
The gas-liquid separation treatment may be performed after cooling the solid liquid and the gas or before cooling, and is not particularly limited. That is, the more preferable one is adopted in the processing at that time. For example, it is preferable to perform the gas-liquid separation process without cooling, in the case where the primary treatment liquid needs to be cooled due to a large amount of heat generated in the first process, the fourth process is performed. When the oxygen-containing gas temperature in the fourth step is better because the heat for raising the temperature is insufficient, or it is necessary to concentrate the primary treatment liquid in order to remove solids in the primary treatment liquid with high efficiency. There are cases such as On the contrary, it is preferable to perform the gas-liquid separation treatment after cooling, when the raw wastewater needs to be preheated with as much heat as possible because the heat generation in the first step is small. Four
When the temperature of the oxygen-containing gas in the 4th step is better because of the large amount of heat generated in the process, or when the primary treatment liquid is concentrated because the amount of solids or salt concentration in the primary treatment liquid is high, a gas-liquid separator Occasionally, there is a case where a line or the like is blocked.

The treatment pressure of the non-catalytic wet oxidation treatment or the treatment pressure of the catalytic wet oxidation treatment of the present invention is appropriately selected depending on the correlation with each treatment temperature, and the pressure is such that the liquid retains the liquid phase. However, the second and fourth steps of the present invention are
A pipeline is connected to use the exhaust gas generated in the first step as an oxygen-containing gas in the fourth step. Therefore, the pressure in the fourth step needs to be the same as or slightly lower than the pressure in the first or second step. When the pressure in the fourth step is higher, it is technically possible to supply by using a compressor or the like, but this is not preferable. If the pressure in the fourth step is considerably lower than the pressure in the first or second step, it can be controlled using a pressure control valve or the like. On the other hand, the pressure in the first or second step and the fourth step is
It is preferable that they are substantially the same, and the pressure that can be easily controlled is 5 kg / cm ² or less, preferably 1 kg / cm ^2.
It is effective that the pressure difference is not more than cm ² .

In the present invention, after the fourth step, it is not particularly specified whether or not the gas-liquid separation treatment is carried out, and when the gas-liquid separation treatment is carried out, the same as in the second step of the present invention. The liquid and the gas may be cooled or may be cooled before cooling, and there is no particular limitation.

In the treatment method of the present invention, after the second step, the solid matter produced in the first step is solid-liquid separated and removed from the primary treatment liquid using a solid-liquid separation treatment device. As the solid-liquid separation treatment device, various devices such as a sedimentation separation treatment device, a centrifugal separation treatment device, or a filtration separation treatment device can be adopted, and are not particularly limited. Further, the pressure may be released once after the second step and the solid-liquid separation treatment may be performed after the primary treatment liquid is brought to the atmospheric pressure, or the first step, the second step, the third step, and the fourth step. It may be of a solid-liquid separation type under high pressure conditions in which each process is connected by a pipeline and each device is operated continuously under high pressure. At this time, although not particularly limited, a flocculant, a flocculation aid, a filter aid, or the like is used if necessary,
It is also possible to improve the processing speed and the separation efficiency.
As the coagulant, coagulant aid, or filter aid, various conventional ones can be used, and the coagulant is not particularly limited, but an organic polymer system is preferably used as the coagulant. preferable. The water-soluble inorganic coagulant may cause catalyst poisoning in the subsequent catalytic wet oxidation treatment, and its use is often limited. As the coagulant aid, various conventional substances can be used like the coagulant, and are not particularly limited, but as the coagulant aid, an organic substance or a water-insoluble inorganic substance can be used. It is preferable to use an aggregation aid. The water-soluble inorganic coagulation aid may cause catalyst poisoning in the subsequent catalytic wet oxidation treatment, and its use is often limited.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0049]

【Example】

(Example 1) Using the non-catalytic wet oxidation treatment apparatus and the solid-liquid separation treatment apparatus shown in FIG. 1, the non-catalytic wet oxidation treatment and the solid-liquid separation treatment were continuously performed for 500 hours. And 5
Using the treatment liquid obtained after 00 hours, TOC and COD (Cr) were measured to determine the concentration and treatment efficiency. Regarding the odor of exhaust gas, the odor concentration was measured by the three-point comparison odor bag method.

For detailed usage of this processing apparatus, the pressure control valve 7 is manually closed and the exhaust gas supply line valve 15 is used.
Open, and the secondary side oxygen-containing gas supply line valve 17 is closed, and the waste water sent from the waste water supply line 8 is discharged by the waste water supply pump 3 at a flow rate of 1 liter / hr to 80 kg / cm ^2.
The pressure was fed to G. On the other hand, after the pressure of the air supplied from the oxygen-containing gas supply line 9 is increased by the compressor 6, the waste water is mixed at a ratio of O ₂ / COD (Cr) (oxygen content in air / chemical oxygen demand) = 2.0. Mixed in. This gas-liquid mixture is heated in the heat exchanger 2 via the gas-liquid mixture supply line 10 and then introduced into the non-catalytic wet oxidation reaction tower 1 (empty tower) from the bottom, and the non-catalytic wet oxidation treatment is carried out at a treatment temperature of 255 ° C. Then, the liquid to be treated was cooled in the heat exchanger 2 through the treatment liquid line 11 and flowed to the gas-liquid separator 4. The space velocity of this wastewater was 1.0 hr- ¹ . Gas-liquid separator 4
In (1), the liquid level controller (LC) detects the liquid level and operates the liquid level control valve 6 to maintain a constant liquid level. The treatment liquid discharged from the primary treatment liquid discharge line 13 is subjected to solid-liquid separation treatment by the pressure filtration type solid-liquid separation treatment device 14.

Subsequently, catalytic wet oxidation treatment was performed using the solid-liquid separated liquid. As for detailed usage of this processing apparatus, the solid-liquid separation filtrate sent from the filtrate supply line 24 was pressure-fed to 80 kg / cm ² G by the filtrate supply pump 20 at a flow rate of 1 liter / hr. On the other hand, the oxygen concentration generated by the non-catalytic wet oxidation treatment is 15.5 to 16.7.
Exhaust gas containing oxygen by volume was supplied from the exhaust gas reuse line 12 and mixed into the treatment liquid. This gas-liquid mixture is heated in a heat exchanger 19 via a gas-liquid mixture supply line 25, and then catalytic wet oxidation in which 1 liter of a catalyst composed of titanium-zirconium oxide and platinum (0.4% by weight of platinum) is filled. It is introduced into the reaction tower 18 from the bottom, and the treatment temperature is 25
Catalytic wet oxidation treatment at 5 ° C and treatment liquid is treated liquid line 2
6 and then cooled in the heat exchanger 19, and the gas-liquid separator 2
Shed to 1. The space velocity of this solid-liquid separated liquid is 1.0 hr ~ ¹
Met. In the gas-liquid separator 21, the liquid level controller (LC) detects the liquid level to operate the liquid level control valve 22 to maintain a constant liquid level, and the pressure controller (PC) detects the pressure. Pressure control valve 23
Is operated to maintain a constant pressure.

The property of the wastewater used for the treatment is that iron is 6
30 mg / liter, TOC 16.2 g / liter,
The COD (Cr) was 52.5 g / liter.

The results obtained after the non-catalytic wet oxidation treatment and the solid-liquid separation treatment were iron 1 mg / liter or less, TOC
8.9 g / liter, COD (Cr) concentration 27.3 g / liter, TOC treatment efficiency 45%, COD (C
r) The treatment efficiency was 48%.

The results obtained after the catalytic wet oxidation treatment are TOC 1.7 g / liter and COD (Cr) 4.
TOC for each primary treatment liquid at 9 g / liter
The treatment efficiency was 81% and the COD (Cr) treatment efficiency was 82%. Therefore, the TOC and COD (Cr) treatment efficiencies calculated from the raw wastewater in this example are 90% each.
% And 91%. The exhaust gas after the catalytic wet oxidation had almost no odor, and the odor concentration was 100 times or less.

Example 2 Using the apparatus shown in FIG. 1, the same operation as in Example 1 was continuously carried out for 500 hours under the following conditions under non-catalytic wet oxidation treatment, gas-liquid separation treatment and solid-liquid separation treatment. And the catalytic wet oxidation treatment, and the treated liquid after 500 hours was analyzed.

The non-catalytic wet oxidation treatment conditions are as follows: waste water flow rate 0.5 liter / hr, waste water space velocity 0.5 hr- ¹ .
O ₂ / COD (Cr) (oxygen content in air / chemical oxygen demand) = 1.0, processing pressure 9 kg / cm ² G, processing temperature 1
It was 60 ° C.

The catalyst wet oxidation treatment conditions are as follows: flow rate of solid-liquid separation liquid 0.5 liter / hr, space velocity of solid-liquid separation liquid 0.5.
hr ~ ¹ , processing pressure 9 kg / cm ² G, processing temperature 160 ° C
As the catalyst, 1 liter of a catalyst composed of titanium-iron oxide and ruthenium (1% by weight of ruthenium) was used.

The property of the wastewater used for the treatment is 85 mg of phosphorus.
/ Liter, TOC 8.7g / liter and COD
(Cr) was 34.5 g / liter.

The results obtained after the non-catalytic wet oxidation treatment and the solid-liquid separation treatment were phosphorus of 1 mg / liter or less, TO
C 5.7 g / liter and COD (Cr) 19.5 g /
TOC processing efficiency 34%, COD in liters
The (Cr) treatment efficiency was 43%. The oxygen concentration of the exhaust gas generated by the non-catalytic wet oxidation treatment is 11.5-12.6% by volume.
Met.

The results obtained by the catalytic wet oxidation treatment are TOC 2.1 g / liter and COD (Cr) 6.
TOC for each primary treatment liquid at 1 g / liter
The treatment efficiency was 63% and the COD (Cr) treatment efficiency was 69%. Therefore, the treatment efficiency of TOC and COD (Cr) calculated from the raw wastewater in this example is 7
6% and 82%. The exhaust gas after the catalytic wet oxidation had almost no odor, and the odor concentration was 100 times or less.

(Comparative Example 1) The oxygen-containing gas used in the catalytic wet oxidation treatment was not the exhaust gas containing oxygen generated in the non-catalytic wet oxidation treatment, but the air newly pressurized by the compressor 29 was used. The same treatment as in Example 1 was carried out. As for the detailed usage of the treatment apparatus, the pressure of the gas-liquid separator 4 is detected by the pressure controller to control the pressure control valve 7, the pressure of the reaction system is controlled at 80 kg / cm ² G, and the exhaust gas on the primary treatment side is It was discharged from the exhaust gas discharge line 30. Further, the exhaust gas supply line valve 15 is closed, the secondary side oxygen-containing gas supply line valve 17 is opened, and the oxygen-containing gas of the catalytic wet oxidation process is obtained by compressing the air pressurized by the compressor 29 with O ₂ / COD (Cr) = 1. It was supplied at 0.0.

The results obtained after the non-catalytic wet oxidation treatment and the solid-liquid separation treatment were iron 1 mg / liter or less, TOC
8.9 g / liter, COD (Cr) concentration 27.3 g / liter, TOC treatment efficiency 45%, COD (C
r) The treatment efficiency was 48%, which was the same as in Example 1. However, the exhaust gas after the non-catalytic wet oxidation treatment had a slight odor, and the odor concentration was about 1500 times.

The results obtained after the catalytic wet oxidation treatment are TOC 2.1 g / liter and COD (Cr) 6.
TOC for each primary treatment solution at 3 g / liter
The treatment efficiency was 76% and the COD (Cr) treatment efficiency was 77%. Therefore, the treatment efficiencies of TOC and COD (Cr) calculated from the raw wastewater in this example are 87 respectively.
% And 88%. The exhaust gas after the catalytic wet oxidation had almost no odor, and the odor concentration was 100 times or less.

[Brief description of drawings]

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

[Explanation of symbols]

 1. Non-catalytic wet oxidation reaction tower 2. Heat exchanger 3. Waste water supply pump 4. Gas-liquid separator 5. Compressor 6. Liquid level control valve 7. Pressure control valve 8. Waste water supply line 9. Oxygen-containing gas supply line 10. Gas-liquid mixture supply line 11. Processing liquid line 12. Exhaust gas reuse line 13. Treatment liquid discharge line 14. Solid-liquid separation treatment device 15. Exhaust gas supply line valve 16. Check valve 17. Secondary side oxygen-containing gas supply line valve 18. Catalyst wet oxidation reaction tower 19. Heat exchanger 20. Filtrate supply pump 21. Gas-liquid separator 22. Liquid level control valve 23. Pressure control valve 24. Filtrate supply line 25. Gas-liquid mixture supply line 26. Processing liquid line 27. Exhaust gas discharge line 28. Process liquid discharge line 29. Compressor 30. Exhaust gas discharge line

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location C02F 1/60 ZAB 1/62 ZAB Z (72) Inventor Kunio Sano Kyoo Sano, Hamaji-ku, Hyogo Prefecture Nishi-oki 992 No. 1 Inside Nippon Shokubai Catalysis Laboratory

Claims (3)

[Claims] 1. (1) Non-catalytic wet oxidation, which is a primary treatment of wastewater under a pressure at which the wastewater holds a liquid phase at a temperature of 140 ° C. to 370 ° C. while supplying a gas containing oxygen to the wastewater. Treated, (2) then separate the primary treatment exhaust gas by gas-liquid separation treatment, (3) solid-liquid separation treatment of the solid-containing treatment wastewater obtained by the primary treatment, (4) after the solid-liquid separation treatment In the method of performing catalytic wet oxidation treatment of the filtrate of 1. at a temperature of 140 ° C. to 370 ° C. and a pressure at which the filtrate retains a liquid phase, the primary treatment exhaust gas is supplied to the catalytic wet oxidation step to perform catalytic wet oxidation treatment. A characteristic wastewater treatment method. 2. A non-catalytic wet oxidation process, a gas-liquid separation process, a solid-liquid separation process, and a catalytic wet oxidation process are sequentially connected by a pipeline, and each process is continuously operated under high pressure. The wastewater treatment method described. 3. The method for treating wastewater according to claim 1, wherein 1 liter or more of at least one of heavy metals, aluminum, phosphorus, silicon, calcium or magnesium is contained in 1 liter of the wastewater.