JPH0454513B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for wet oxidation treatment of wastewater containing two or more of suspended solids, ammonia and COD components. Conventional techniques and their problems In recent years, from the perspective of water quality conservation, not only the removal of chemical oxygen-requiring substances (herein referred to as COD components) but also the removal of nitrogen components (particularly ammonia nitrogen) has become important. In view of the current situation, the present inventors have conducted various experiments and research, and have established a practical treatment technology that can simultaneously decompose and remove COD components and ammonia in wastewater.
No. 19757, Special Publication No. 57-42391, Special Publication No. 59-29317
No., Special Publication No. 57-33320, etc.). However, if the treated wastewater contains suspended solids (hereinafter referred to as SS) at a high concentration of 5 million to tens of thousands of ppm, undecomposed SS may adhere to the equipment that makes up the wastewater treatment equipment. For example, there is a tendency for a decrease in the heat transfer coefficient on the surface of the heat exchanger, an increase in pressure loss due to adhesion to the surface of the catalyst packed in the reactor, and a decrease in catalyst activity. In some cases, it may be necessary to remove all or part of it prior to processing. On the other hand, when treating wastewater containing high concentrations of SS using the currently widely adopted biological treatment method, most of the SS must be removed beforehand and then treated, or the SS must be treated without being removed beforehand. Extracted from the system as surplus sludge, incinerated, melted,
They are landfilling, dumping into the ocean, and turning it into fertilizer. However, the amount of sludge generated during wastewater treatment, including the amount generated from each sewage treatment plant, continues to increase every year. Therefore, there is a strong need for measures to reduce the amount of sludge generated and disposal as much as possible, and for the establishment of a permanent disposal method that can economically process the constantly generated sludge. Means for Solving the Problems In view of the current state of technology, the present inventor will continue to conduct intensive research in order to further improve the above-mentioned prior invention and complete a wastewater treatment method that can simultaneously decompose high-concentration SS. As a result of repeated efforts, the inventors discovered that the objective could be achieved by combining a liquid phase oxidation step carried out in the absence of a catalyst and a liquid phase oxidation step carried out in the presence of a specific catalyst, and completed the present invention. It came to this. That is, the present invention provides the following two wastewater treatment methods. When carrying out wet oxidation treatment of wastewater containing two or more of suspended solids, ammonia and COD components, () a step of liquid phase oxidation of wastewater in the absence of a catalyst and in the presence of an oxygen-containing gas; () a honeycomb structure; and () liquid-phase oxidation of the treated water from the above step () in the presence of an oxygen-containing gas; and () oxidizing iron, cobalt,
In the presence of a catalyst supporting at least one of nickel, ruthenium, rhodium, palladium, iridium, platinum, copper, gold, tungsten, and compounds of these metals that are insoluble or sparingly soluble in water and in the presence of an oxygen-containing gas. A wet oxidation treatment method (hereinafter referred to as the present invention), comprising a step of liquid-phase oxidation of the treated water from the above step (). When wet oxidizing wastewater containing two or more of suspended solids, ammonia and COD components, () a step of liquid phase oxidation of wastewater in the absence of a catalyst and in the presence of an oxygen-containing gas; () a honeycomb structure; and in the presence of an oxygen-containing gas, a step of liquid-phase oxidation of the treated water from the above step ();
In the presence of a catalyst supporting at least one of nickel, ruthenium, rhodium, palladium, iridium, platinum, copper, gold, tungsten, and compounds of these metals that are insoluble or sparingly soluble in water and in the presence of an oxygen-containing gas. A step of liquid-phase oxidation of the treated water from the above step (), and () iron, cobalt, nickel,
The above step is carried out in the presence of a catalyst supporting at least one of ruthenium, rhodium, palladium, iridium, platinum, copper, gold, tungsten, and water-insoluble or sparingly soluble compounds of these metals, and in the presence of an oxygen-containing gas. ()
A wet oxidation treatment method for wastewater (hereinafter referred to as the present invention), comprising a step of liquid-phase oxidation of treated water from a wastewater. In the present invention, ammonia contained in wastewater includes ammonium compounds that can form ammonium ions by dissociation in water. COD components also include phenol, cyanide, thiocyanide, oil, thiosulfate, sulfite, sulfide, nitrite, organic chlorine compounds (trichloroethylene, tetrachloroethylene, trichloroethane, methylene chloride, etc.), and the like. Furthermore, suspended solids (SS) refer to substances specified in JIS K 0102, suspended solids specified in the sewage test method by the Japan Water Works Association, and other solid and flammable substances (sulfur, etc.). The method of the present invention uses each of the above components (ammonia,
It is suitable for the treatment of wastewater containing two or three types of COD components and SS). Specific examples of such wastewater include sewage sludge, concentrated sewage sludge, human waste, desulfurization/desulfurization wastewater, coal gasification/liquefaction wastewater, heavy oil gasification wastewater, food factory wastewater, and alcohol manufacturing factory wastewater. , chemical factory wastewater, etc., but are not limited to these. In the first step (hereinafter referred to as -() step) of the present invention, wastewater is oxidized in a liquid phase in the presence of an oxygen-containing gas without using a catalyst. The oxygen-containing gas used in this process includes air, oxygen-enriched gas, oxygen, and one or two of hydrogen cyanide, hydrogen sulfide, ammonia, sulfur oxides, organic sulfur compounds, nitrogen oxides, hydrocarbons, etc. Examples include oxygen-containing waste gas containing the above. The supply amount of these gases is SS in wastewater (or wastewater and waste gas),
Oxygen is supplied in an amount of 1 to 1.5 times, more preferably 1.05 to 1.2 times, the theoretical amount of oxygen required to oxidize and decompose the entire amount of ammonia and COD components into nitrogen, carbon dioxide, water, etc. is good. When oxygen-containing waste gas is used as the oxygen source, there is an advantage that harmful components in the gas can also be treated at the same time. If the absolute amount of oxygen is insufficient when using oxygen-containing waste gas, it is preferable to compensate for the deficiency with air, oxygen-enriched air, or oxygen. In addition, the oxygen-containing gas is
It is not necessary to supply the entire amount of wastewater to the -() process, and it may be distributed and supplied to the -() process and the next process. For example, in the -() process, usually about 10 to 70% of SS, about 10 to 60% of COD components, and about 0 to 15% of ammonia are decomposed, so the amount of oxygen is 0.4 to 0.7 times the theoretical amount. A corresponding oxygen-containing gas may be supplied, and the remainder may be supplied in the next step. -The reaction temperature in step () is usually 100 to 370°C, more preferably 200 to 370°C.
The temperature is around 300℃. The higher the reaction temperature, the higher the oxygen fraction in the supplied gas, and the higher the operating pressure, the higher the decomposition rate of the components to be treated, the shorter the wastewater residence time in the reactor, and the faster the next step. Although the reaction conditions in the process are relaxed, on the other hand, the equipment costs are high, so it is important to consider the type of wastewater, the balance with the reaction conditions in the next process, the degree of treatment required, and the overall operating and equipment costs. It is best to decide based on comprehensive consideration. The pressure during the reaction may be at least the minimum pressure at which the wastewater remains in a liquid phase at a predetermined reaction temperature. Next, the second step of the present invention (hereinafter -()
In step ), the treated water from step -() is again subjected to liquid phase oxidation in the presence of the honeycomb structure.
The honeycomb structure may have an opening of any shape such as a quadrangle, a pentagon, a hexagon, or a quadrilateral.
The area per unit capacity, aperture ratio, etc. are not particularly limited, but usually the area per unit capacity is 200~
Use one with an area of about 800m ² /m ³ and an aperture ratio of about 40 to 80%. Examples of the material for the honeycomb structure include titania and zirconia. The volume of the reactor is such that the space velocity of the liquid is 0.3 to 10 1/Hr (empty column basis).
It is preferable to adjust the temperature to about 0.5 to 4 1/Hr (empty column standard). As mentioned above,
If the entire amount of oxygen required is supplied to the wastewater in the -() step, there is no need to supply oxygen-containing gas in the -() step and the next step;
- Only when only a part of the total required amount of oxygen is supplied in step (), the oxygen-containing gas corresponding to the remaining amount of oxygen is supplied. The reaction temperature in step -() is usually about 100 to 370°C, more preferably about 200 to 300°C. The pressure during the reaction may be at least the minimum pressure at which the waste water can maintain a liquid phase at a predetermined reaction temperature. In the third step (hereinafter referred to as -() step) of the present invention, the treated water from the -() step is further subjected to liquid phase oxidation in the presence of a catalyst supported on a honeycomb-structured carrier. As a honeycomb structure carrier,
- A honeycomb structure having the same shape and material as the honeycomb structure used in step () can be used. Catalytic active ingredients include iron, cobalt, nickel,
Ruthenium, rhodium, palladium, iridium, platinum, copper, gold and tungsten, and their oxides, as well as chlorides such as ruthenium dichloride and platinum dichloride, and sulfides such as ruthenium sulfide and rhodium sulfide. In contrast, compounds that are insoluble or poorly soluble can be mentioned, and one or more of these compounds may be supported on the carrier. The amount supported is not particularly limited, but is usually about 0.05 to 25% of the weight of the carrier, preferably
It is about 0.5 to 3%. The reaction column volume is preferably such that the space velocity of the liquid is about 0.3 to 10 1/Hr (empty column basis), more preferably about 0.5 to 4 1/Hr (empty column basis). As mentioned above, only when a part of the total required amount of oxygen is supplied in the -() process or the -() process and the -() process, the amount of oxygen corresponding to the remaining oxygen amount is supplied in this -() process. Contained gas is supplied. −()
The reaction temperature in the process is usually about 100 to 300℃,
More preferably it is about 200 to 290°C. The pressure during the reaction may be maintained at a level that allows the wastewater to maintain its liquid phase. Thus, the remaining SS, COD components, and ammonia that were not oxidatively decomposed in the steps -() and -() are substantially decomposed. - If the treated water obtained in the step () contains decomposition products such as sodium sulfate and requires desalination for reuse, the water obtained in the fourth step (-
In step (), the pressurized treated water from step -() is directly sent to a reverse osmosis device and separated into purified water and concentrated water. Purified water can be reused for various purposes, such as industrial water, and
The concentrated water can be mixed with raw waste water and subjected to the treatment according to the present invention again, or useful substances such as sodium sulfate can be recovered from the concentrated water. In the first step (hereinafter referred to as step -()) of the present invention, liquid phase oxidation of wastewater is carried out in the absence of a catalyst and in the presence of an oxygen-containing gas under the same conditions as in step -(). The honeycomb structure used in the second step (hereinafter referred to as -() step) of the present invention is -
It is similar to the honeycomb structure used in the () process. However, in the present invention, a step of performing liquid phase oxidation in the presence of a granular catalyst is added, so
The reaction conditions in the -() step can be made milder than those in the -() step. −()
The reaction temperature in the process is usually about 100 to 300℃,
More preferably, the temperature is about 200 to 290°C, and the pressure is
It is sufficient if the pressure is at least the minimum pressure at which the treated water from the -() step can maintain a liquid phase at a predetermined reaction temperature. - When only a part of the oxygen-containing gas is supplied to the wastewater sent to the -() process, the oxygen-containing gas equivalent to the remaining amount of oxygen is supplied in the -() process, or the oxygen-containing gas equivalent to the remaining amount of oxygen is supplied in the -() process. Supply it separately to the following processes. In the latter case, an oxygen-containing gas equivalent to 0.3 to 0.7 times the theoretically required amount of oxygen is used.
It is sufficient to supply it in the () process and supply the remainder in the subsequent process. Third step of the claimed invention (hereinafter referred to as -())
The honeycomb catalyst body used in -()
It may be similar to the honeycomb catalyst body used in the process. The reaction temperature is usually about 100 to 300°C, more preferably about 200 to 290°C, and the pressure may be such that the treated water can exist as a liquid. Further, the oxygen-containing gas may be supplied in this step as well, if necessary. In the fourth step (hereinafter referred to as -() step) of the present invention, the treated water from the -() step is further subjected to liquid phase oxidation treatment in the presence of a catalyst supported on a granular carrier and in the presence of an oxygen-containing gas. do. The reaction temperature is usually about 100 to 300°C, more preferably 200 to 300°C.
The temperature is around 290℃. As a catalytic active component, -
The same catalyst active ingredients as in step () can be used. The catalytic active ingredients are alumina, silica, silica-alumina,
It is used supported on a granular carrier such as titania, zirconia, and activated carbon, or a porous granular metal carrier such as nickel, nickel-chromium, nickel-chromium-aluminum, and nickel-chromium-iron.
In the present specification, "granular" includes various shapes such as spherical, pellet-like, cylindrical, crushed piece-like, and powder-like. The amount of the catalyst active component supported is usually about 0.05 to 25%, more preferably about 0.5 to 3% of the weight of the carrier. The reactor used is a fixed bed type, and its volume is such that the space velocity of the liquid is 0.5 to 10 1/Hr (on a sky column basis), more preferably 1 to 4 1/Hr (on a sky column basis). It is better to do it like this. - If necessary, the pressurized treated water obtained in () is further sent to an osmotic pressure device in the same manner as above and separated into purified water and concentrated water (this is separated into -
() process). -() process is -()
It can be carried out in the same manner as the process. In addition, in the present invention and each step, liquid phase oxidation proceeds particularly well when the pH of the treated water is in the range of about 8 to 11.5, more preferably in the range of about 9 to 11.
Depending on the type of wastewater, the PH of the wastewater may be adjusted in advance using an alkaline substance such as sodium hydroxide, sodium carbonate, or calcium hydroxide, or the -() process, -() process, -
It is preferable to add a similar alkaline substance to the treated water in steps () to -() to adjust its pH. In addition, even if the initial pH of wastewater or treated water used in each process is around 8 to 11.5, as the reaction progresses, the pH of the liquid will drop significantly and the decomposition rate of harmful components will decrease. This may increase the amount of catalyst required, accelerate exhaustion or deterioration of the catalyst, or cause serious damage to the reactor, piping, heat exchanger, etc. due to the acidic liquid. Therefore, the pH of the liquid in the reaction system should always be about 5 or higher, and -()
The pH of the liquid at the process and -() process exit is about 5~
It is desirable to add an alkaline substance similar to the above to the reaction system as appropriate so as to obtain a concentration of 8. The present invention will be described in more detail below with reference to the accompanying drawings. FIG. 1 is a flowchart showing an example of implementation of the present invention. Wastewater containing SS, ammonia, and COD components is pumped from the wastewater storage tank 1 through line 5 by pump 3, pressurized by compressor 7, and mixed with oxygen-containing gas pumped from line 9. It reaches line 15 via heat exchanger 13. If the wastewater has reached a predetermined temperature or higher due to heat exchange in the heat exchanger 13,
First reaction zone 21 via lines 17 and 19
If the specified temperature has not been reached,
It is fed to the reaction zone 21 via line 23, heating furnace 25, line 27 and line 19. If necessary, an alkaline substance is added to the wastewater from the alkaline substance storage tank 29 via line 31, pump 33, line 35 and line 37, usually in the form of an aqueous solution. In the first reaction zone 21, liquid phase oxidation of the wastewater takes place in the presence of oxygen-containing gas without the use of catalysts. The treated water from the first reaction zone 21 is sent to the second reaction zone 22, which fills the honeycomb structure, where it is again subjected to liquid phase oxidation. The treated water from the first reaction zone 21 may be supplied with oxygen-containing gas from the compressor 7 via the line 41,
In addition, the alkaline substance from the storage tank 29 is transferred to the line 31.
It may be added via pump 33, line 35 and line 43. Note that the alkaline substance may be supplied to appropriate positions (not shown) in the first reaction zone 21 and the second reaction zone 22. The treated water from the second reaction zone 22 is further subjected to liquid phase oxidation in the third reaction zone 39, which is filled with a catalyst in which a catalyst active component is supported using a honeycomb structure as a carrier. Second reaction zone 22
An oxygen-containing gas may be supplied to the treated water from the reactor as necessary, and an alkaline substance may be appropriately added to the third reaction zone 39. The treated water subjected to liquid phase oxidation in the third reaction zone 39 enters the heat exchanger 13 via line 45, where it imparts thermal energy to the untreated wastewater, and then enters the cooler 49 via line 47. , cooled. The treated water that has exited the cooler 49 passes through a line 51 and is separated into a gas from a line 55 and a liquid from a line 57 in a gas-liquid separator 53 . Liquid from line 57 enters reverse osmosis device 59 under pressure, clear water from line 61 and line 6
It is separated into concentrated water from 3. The concentrated water is returned to the wastewater storage tank 1 via line 63. FIG. 2 is a flowchart showing an example of implementation of the present invention. In FIG. 2, features that are the same as in FIG. 1 are designated with the same numbers.
The wastewater from the wastewater storage tank 1 is heated by the first heat exchanger 13 and the second heat exchanger 65, and is passed through the line 6.
7 and enters the first reaction zone 69 with or without further heating in the heating furnace 25. The treated water that has been subjected to liquid phase oxidation in a non-catalyzed state in the first reaction zone 69 is further transferred to a second reaction zone 70 filled with a honeycomb structure, a third reaction zone 71 filled with a honeycomb catalyst body, and a particle field oxidation zone 71 filled with a honeycomb structure. Liquid phase oxidation is performed sequentially in a fourth reaction zone 73 filled with a medium. The treated water exiting the fourth reaction zone 73 passes through a line 75 and is passed through the gas-liquid separator 53.
Gas from line 77 and liquid from line 79 are separated. The gas from line 77 imparts thermal energy to the wastewater in heat exchanger 13 and then
It is discharged from the system through line 81. On the other hand, the liquid from the line 79 further heats the waste water in the second heat exchanger 65, enters the cooler 49 via the line 83, is cooled, and then passes through the line 85 either as it is or after being depressurized and subjected to reverse osmosis. Enter device 59;
Clear water from line 61 and concentrated water from line 63 are separated. In the flow shown in FIG. 1, an example is shown in which independent first to third reaction zones are used, but the first to third reaction zones may be formed in a single reaction column, or It is also possible to form the first and second reaction zones in the first reaction column and the third reaction zone in the second reaction column. Also, in the flow shown in FIG. 2, it is possible to have a similar configuration.
Needless to say. In addition, in the present invention, line 45 in FIG.
The treated water may be sent to a gas-liquid separator similar to the gas-liquid separator 53 in FIG. 2, and thereafter treated in the same flow as in FIG. 2. Similarly, in the present invention, the treated water from the line 75 in FIG. 2 may be sent to a heat exchanger similar to the heat exchanger 13 in FIG. 1, and thereafter treated by the same flow as in FIG. good. Effects of the Invention According to the present invention, wastewater containing not only ammonia and COD components but also highly concentrated suspended solids can be efficiently treated. Moreover, decolorization, deodorization, and sterilization of wastewater are also performed at the same time. Examples Examples will be shown below to further clarify the features of the present invention. Example 1 According to the present invention, human waste was subjected to liquid phase oxidation treatment according to the flow shown in FIG. The composition of the raw human waste is as shown in Table 1, and coarse plastic pieces, paper pieces, etc. were removed using a swing disk screen (opening diameter 3 mm).

[Table] - () Process: Add 20% sodium hydroxide solution to raw human urine to adjust the pH.
After adjusting the temperature to about 9, the reactant was supplied to the lower part of the first reaction zone 21 at a space velocity of 2.0 1/Hr (based on the sky column) and a mass velocity of 2.39 t/m ² Hr. On the other hand, space velocity 89.8
1/Hr (sky tower standard, standard state conversion)
was supplied to the lower part of the reaction zone 21. In this state, the wastewater was subjected to non-catalytic liquid phase oxidation treatment under conditions of a temperature of 280°C and a pressure of 90 kg/cm ² ·G. Table 2 shows the composition of the treated water obtained in this step.

[Table] - () Process: The opening shape is square (one side length 3.5 mm),
The treated water from the above process -() is filled into the second reaction zone 22 filled with a titania honeycomb structure with a cell pitch of 4.5 mm and an aperture ratio of 59.3% in an amount equal to the empty column volume in the process -(). After addition of 20% aqueous sodium hydroxide solution, liquid phase oxidation was performed. The reaction temperature and pressure were the same as in the -() step. Table 3 shows the composition of the treated water obtained in this step.

【table】

[Table] -() process: A honeycomb catalyst body in which palladium of 2% of the structure weight was supported on a titania honeycomb structure similar to that used in the -() process was used as -() and -.
The treated water from the above step -() was introduced into the third reaction zone 39, which was filled so as to have an empty column volume equal to that of the step (), and was further subjected to liquid phase oxidation. The reaction temperature and pressure were 280℃ and 90Kg/cm ²・G, respectively.
It was hot. Table 4 shows the composition of the treated water obtained in this step. The treated water was decolored and deodorized to the same extent as tap water in appearance.

[Table] - () process: - After the treated water from the () process is cooled by the heat exchanger 13 and the cooler 49, the gas-liquid separator 53
The liquid phase side pressure was adjusted to 65 kg/cm ² and led to a reverse osmosis device 59. In this way, 85 parts by weight of clear water and 15 parts by weight of concentrated water were obtained from 100 parts by weight of water supplied to the reverse osmosis device 59. The quality of clear water is shown in Table 5.

[Table] Concentrated water was returned to wastewater storage tank 1 via line 63. The exhaust gas composition from the gas-liquid separator 53 is:
NH ₃ 0.01ppm or less, SO _x 0.01ppm or less,
NO _x was not detected. Even after treating wastewater containing high concentrations of SS for a total of 5,000 hours, no precipitation or adhesion of SS to the catalyst body or a decrease in the decomposition rate of each component was observed, indicating that wastewater treatment could continue without any problems. did it. Example 2 Human waste was subjected to liquid phase oxidation treatment according to the present invention according to the flow shown in FIG. The composition of the human urine was the same as in Example 1. First, the -() step was carried out in the same manner as the -() step of Example 1. -() process, -() process and -()
The amount of carrier or catalyst packed in the process was made to be the same as the empty column volume in the -() process of Example 1.
In both the -() step and the -() step, a catalyst supporting 2% by weight of ruthenium was used. In addition, at the -() process and -() inlet so that the pH of the liquid at the -() process outlet is 7.5.
A 20% aqueous sodium hydroxide solution was fed. Table 6 shows the water quality at each process outlet.

[Table] Note that during the exhaust from the gas-liquid separator 53,
NH ₃ , SO _x and NO _x were not detected. Examples 3 to 12 According to the present invention, human waste similar to that in Example 1 was subjected to liquid phase oxidation treatment according to the flow shown in FIG. −(), −(), −() and −()
In both processes, the temperature is 250℃ and the pressure is 70℃.
The condition of Kg/cm ²・G was adopted. The liquid space velocity is
-() and -() processes are each 1.0 1/Hr (empty column standard), -() and -() are 0.67 in total
1/Hr (empty column basis), and the catalyst filling ratio in the -() step and in the -() step was 1:1. or,
In the step -(), the zirconia honeycomb structure was packed to have the same empty column volume as in the step -(). - The packed catalyst in step () is as shown in Table 7. In step -(), a catalyst was used in which 2% by weight of palladium or 2% by weight of ruthenium was supported on a spherical zirconia carrier having a diameter of 5 mm. Conditions other than the above were the same as in Example 2.
Table 7 shows the quality of the treated water obtained in the -() and -() steps.

【table】

[Table] Examples 13 to 16 - Liquid phase oxidation treatment of human waste was carried out in the same manner as in Example 4, except that the catalyst used in the step () was as shown in Table 8. Table 8 shows the quality of the treated water in each process. In any of the examples, NH ₃ , NO _x and SO _x were not detected in the exhaust gas from the gas-liquid separator 53.

[Table] Example 18 According to the flow shown in FIG. 2, sewage sludge concentrate having the composition shown in Table 9 below was subjected to liquid phase oxidation treatment according to the present invention. The processing conditions were the same as in Example 2, except that the amount of air was 1.2 times the amount corresponding to the theoretical amount of oxygen.
The same is true.

【table】

【table】 Table 10 shows the quality of the treated water in each process.

【table】

[Table] When SS was separated from the treated water from the -() outlet, it had the same appearance as tap water and was completely deodorized. Furthermore, an analysis of SS in the treated water at the -() outlet revealed that 98% was nonflammable. From the exhaust gas from the gas-liquid separator 53, NH ₃ ,
NO _x and SO _x were not detected. Examples 19 to 23 Except that the catalysts used in the -() and -() steps were shown in Tables 11 and 12,
In the same manner as in Example 2, human waste was subjected to liquid phase oxidation treatment. The quality of treated water in each process is shown in Tables 11 and 12.
It is also shown in the table.

【table】

【table】 [Brief explanation of drawings]

1 and 2 are flowcharts illustrating embodiments of the present invention. DESCRIPTION OF SYMBOLS 1... Waste water storage tank, 3... Pump, 7... Compressor, 13... Heat exchanger, 21... First reaction zone, 22... Second reaction zone, 25... Heating furnace, 29... ... Alkaline substance storage tank, 33 ... Pump, 39 ... Third reaction zone, 49 ... Cooler, 53 ... Gas-liquid separator, 59 ... Reverse osmosis device,
65... Second heat exchanger, 69... First reaction zone, 70... Second reaction zone, 71... Third
reaction zone, 73... fourth reaction zone.

Claims (1)

[Claims] 1. In wet oxidation treatment of wastewater containing two or more of suspended matter, ammonia, and COD components, () liquid phase oxidation of wastewater in the absence of a catalyst and in the presence of an oxygen-containing gas. a step of () liquid-phase oxidation of the treated water from the above step () in the presence of a honeycomb structure and in the presence of an oxygen-containing gas; and () a step of oxidizing iron, cobalt, nickel, ruthenium, rhodium, palladium,
The treated water from the above step () is treated in the presence of a catalyst supporting at least one of iridium, platinum, copper, gold, tungsten, and compounds of these metals that are insoluble or poorly soluble in water and in the presence of an oxygen-containing gas. A wet oxidation treatment method comprising a step of liquid phase oxidation. 2. When wet oxidizing wastewater containing two or more of suspended matter, ammonia, and COD components, () a step of liquid phase oxidation of wastewater in the absence of a catalyst and in the presence of an oxygen-containing gas; () a honeycomb structure; a step of liquid-phase oxidation of the treated water from the above step () in the presence of an oxygen-containing gas and an oxygen-containing gas; () iron, cobalt, nickel, ruthenium, rhodium, palladium,
The treated water from the above step () is treated in the presence of a catalyst supporting at least one of iridium, platinum, copper, gold, tungsten, and compounds of these metals that are insoluble or poorly soluble in water and in the presence of an oxygen-containing gas. and () at least one of iron, cobalt, nickel, ruthenium, rhodium, palladium, iridium, platinum, copper, gold and tungsten, and water-insoluble or sparingly soluble compounds of these metals, on a granular carrier. A method for wet oxidation treatment of wastewater, comprising the step of liquid-phase oxidation of the treated water from the above step (2) in the presence of a catalyst supporting one type of catalyst and in the presence of an oxygen-containing gas.