Method for treating organic wastewater through wet oxidation

Abstract

The invention relates to a method for treating organic wastewater through wet oxidation, which comprises the following steps: carrying out wet oxidation treatment on the organic wastewater in the presence of a catalyst, the catalyst comprises a first catalyst and a second catalyst, the first catalyst comprises soluble transition metal salt, and the second catalyst comprises a carrier and rare earth metal loaded on the carrier. According to the method disclosed by the invention, the homogeneous transition metal salt and the heterogeneous rare earth metal-loaded carrier are used as the mixed catalyst, and when the mixed catalyst is used for wet oxidation treatment of the organic wastewater, the transition metal in the first catalyst and the rare earth metal in the second catalyst have a synergistic effect, so that the content of refractory organic matters in the organic wastewater can be reduced; the biodegradability is improved, so that the treated wastewater has a lower COD (Chemical Oxygen Demand) value and a higher B / C (Browser / Carrier) value and can be directly discharged into a sewage treatment plant.

Description

Technical Field

[0001] The present disclosure relates to a wastewater treatment method, and in particular, to a method for treating organic wastewater by wet oxidation. Background Art

[0002] In the process of industrial production, a type of wastewater with high organic concentration is often produced. Since this type of wastewater contains relatively high organic components and sometimes toxic and harmful substances, it is difficult to meet the discharge requirements by using simple biochemical treatment methods. The use of combustion and other methods to treat concentrated organic wastewater not only consumes a lot of energy and has high operating costs, but also easily causes secondary pollution. The wet oxidation method for treating concentrated organic wastewater has the advantages of high efficiency, energy saving and stable operation. Therefore, it has received widespread attention and popularity. The wet oxidation of high-concentration organic wastewater is to oxidize the high-concentration organic wastewater and air (or oxygen) at a higher temperature and pressure to react so that the organic matter in the wastewater is oxidized and decomposed into carbon dioxide and water.

[0003] CN1084496A discloses a catalyst for wet oxidation purification of industrial sewage containing high concentrations of organic matter and ammonia and a preparation method thereof. The catalyst is composed of a noble metal component (one of Pt, Pd, Ru, Ir, Rh) and a rare earth element supported on TiO 2 The above composition, wherein the weight content of precious metal is 0.3-1%. -1 Under the following conditions, the COD removal rate can reach 98.5%, and the ammonia nitrogen removal rate can reach more than 99.6%. Due to the high content of precious metals, the catalyst has high manufacturing cost and high processing cost. Summary of the invention

[0004] The purpose of the present disclosure is to provide a method for treating organic wastewater by wet oxidation, which adopts a homogeneous transition metal salt and a heterogeneous rare earth metal-loaded carrier as a mixed catalyst, can reduce the content of organic matter in the organic wastewater, improve biodegradability, and make the treated wastewater have a lower COD value and a higher B / C value.

[0005] In order to achieve the above-mentioned purpose, the present disclosure discloses a method for wet oxidation treatment of organic wastewater, which method comprises: wet oxidation treatment of organic wastewater in the presence of a catalyst; the catalyst comprises a first catalyst and a second catalyst, the first catalyst comprises a soluble transition metal salt, and the second catalyst comprises a carrier and a rare earth metal loaded on the carrier.

[0006] Optionally, the method comprises: mixing the organic wastewater and a concentrated solution of ammoximation process wastewater to obtain mixed wastewater; adjusting the pH of the mixed wastewater to below 6, and performing the wet oxidation treatment.

[0007] Optionally, the soluble transition metal salt is selected from one or more of soluble iron salts, soluble cobalt salts, soluble nickel salts and soluble platinum salts, preferably a soluble iron salt, and more preferably ferrous sulfate; the content of soluble transition metal salts in the mixed wastewater is 100-12000 mg / L, preferably 500-11000 mg / L, and more preferably 3000-10000 mg / L.

[0008] Optionally, the carrier is selected from one or more of activated carbon, molecular sieves and activated coke, preferably activated carbon; the rare earth metal is selected from cerium and / or lanthanum, preferably cerium; based on the total weight of the carrier, the content of the rare earth metal calculated as the metal element is 0.2 to 5 weight%, preferably 0.3 to 4 weight%.

[0009] Optionally, the COD in the mixed wastewater is 2 O 2 The content ratio of the detected object is 1: (0.1-5), preferably 1: (0.3-2); 2 O 2 The content of the detected object is 300 to 22000 mg / L, preferably 1000 to 20000 mg / L, and more preferably 10000 to 18000 mg / L.

[0010] Optionally, the COD of the organic wastewater is 500-50000 mg / L, preferably 1000-30000 mg / L; B / C is 0-0.3, preferably 0-0.2; the COD of the ammoximation industrial wastewater is 300-30000 mg / L, preferably 500-15000 mg / L; 2 O 2 The content of the detected object is 200 to 30000 mg / L, preferably 500 to 15000 mg / L; B / C is 0 to 0.3, preferably 0 to 0.2.

[0011] Optionally, the preparation method of the concentrated solution comprises: concentrating the ammoximation process wastewater by a reduced pressure distillation method or a membrane concentration method to obtain the concentrated solution and fresh water; preferably, the volume of the concentrated solution is 1 to 10% of the volume of the ammoximation process wastewater.

[0012] Optionally, the temperature of the reduced pressure distillation is 50-100° C., preferably 60-90° C.; the time is 0.2-10 h, preferably 0.5-5 h; the vacuum degree is 0.01-0.1 KPa, preferably 0.02-0.08 KPa.

[0013] Optionally, the conditions of the wet oxidation treatment include: a temperature of 80 to 400°C, preferably 100 to 300°C, more preferably 120 to 250°C; a pressure of 1.0 to 15 MPa, preferably 1.5 to 10 MPa, more preferably 2 to 7 MPa; the wet oxidation treatment is carried out in a reactor, and the reactor includes a fixed bed reactor, a fluidized bed reactor or a tank reactor; preferably, the wet oxidation treatment is carried out in a fixed bed reactor, and the volume liquid hourly space velocity of the reaction is 0.05 to 30 h -1 , preferably 0.2 to 10 hours -1 .

[0014] Optionally, the method further comprises: introducing an oxidizing gas into the mixed wastewater, wherein the amount of the oxidizing gas introduced is 1 to 3 times, preferably 1.05 to 1.5 times, the amount of oxidant required for the COD value in the mixed wastewater; preferably, the oxidizing gas comprises oxygen and / or air.

[0015] Through the above technical scheme, the present disclosure provides a method for wet oxidation treatment of organic wastewater. The method adopts a homogeneous transition metal salt and a heterogeneous rare earth metal-loaded carrier as a mixed catalyst. When used for wet oxidation treatment of organic wastewater, the transition metal in the first catalyst and the rare earth metal in the second catalyst have a synergistic effect, which can reduce the content of difficult-to-degrade organic matter in the organic wastewater and improve biodegradability, so that the treated wastewater has a lower COD value and a higher B / C value, and can be directly discharged to a sewage treatment plant, thereby achieving the purpose of treating waste with waste.

[0016] Other features and advantages of the present disclosure will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0017] The specific embodiments of the present disclosure are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0018] A first aspect of the present disclosure provides a method for wet oxidation treatment of organic wastewater, the method comprising: subjecting the organic wastewater to wet oxidation treatment in the presence of a catalyst; the catalyst comprising a first catalyst and a second catalyst, the first catalyst comprising a soluble transition metal salt, the second catalyst comprising a carrier and a rare earth metal loaded on the carrier.

[0019] The present invention provides a method for treating organic wastewater by wet oxidation. The method adopts a homogeneous transition metal salt and a heterogeneous carrier loaded with rare earth metals as a mixed catalyst. When used for treating organic wastewater by wet oxidation, the transition metal in the first catalyst and the rare earth metal in the second catalyst have a synergistic effect, which can reduce the content of refractory organic matter in the organic wastewater and improve biodegradability, so that the treated wastewater has a lower COD value and a higher B / C value, and can be directly discharged to a sewage treatment plant.

[0020] In one embodiment of the present disclosure, the method comprises: mixing the organic wastewater and the concentrated solution of the ammoximation process wastewater to obtain mixed wastewater; adjusting the pH of the mixed wastewater to below 6, and performing the wet oxidation treatment. The inventors of the present disclosure have found in their research that when the concentrated solution of the organic wastewater and the ammoximation process wastewater are mixed and wet oxidation treatment is performed under the presence of the above-mentioned catalyst, the transition metal in the first catalyst and the rare earth metal in the second catalyst have a synergistic effect, which can promote the removal of H in the concentrated solution. 2 O 2 The detected substances react with the organic matter in the organic wastewater, further reducing the content of difficult-to-degrade organic matter in the organic wastewater, improving biodegradability, and making the treated wastewater have a lower COD value and a higher B / C value, so that it can be directly discharged into the sewage treatment plant to achieve the purpose of treating waste with waste.

[0021] In one embodiment of the present disclosure, the soluble transition metal salt is selected from one or more of soluble iron salts, soluble cobalt salts, soluble nickel salts and soluble platinum salts, preferably soluble iron salts, more preferably ferrous sulfate; the content of soluble transition metal salts in the mixed wastewater is 100-12000 mg / L, preferably 500-11000 mg / L, more preferably 3000-10000 mg / L. In the above embodiment, by selecting a preferred homogeneous soluble transition metal salt as the first catalyst, it is beneficial for the first catalyst to contact the mixed wastewater evenly and improve its catalytic effect.

[0022] In one embodiment of the present disclosure, the carrier is selected from one or more of activated carbon, molecular sieves and activated coke, preferably activated carbon; the rare earth metal is selected from cerium and / or lanthanum, preferably cerium; based on the total weight of the carrier, the content of the rare earth metal calculated as the metal element is 0.2 to 5% by weight, preferably 0.3 to 4% by weight, and more preferably 0.5 to 4% by weight.

[0023] In one embodiment of the present disclosure, the COD in the mixed wastewater is 2 O 2 The content ratio of the detected substances is 1: (0.1-5), preferably 1: (0.3-2); in a preferred embodiment, the mixed wastewater is H2 O 2 The content of the detected substance is 300 to 22000 mg / L, preferably 1000 to 20000 mg / L, and more preferably 10000 to 18000 mg / L. 2 O 2 The detected objects are those with H 2 O 2 The content of the detected substance is detected by the method of GB1616-2003. In the above embodiment, by selecting the preferred mixed wastewater, it is beneficial for the organic matter in the mixed wastewater to fully contact with the organic peroxide-like substance, thereby improving the catalytic effect of the catalyst.

[0024] In one embodiment of the present disclosure, the COD of the organic wastewater is 500-50000 mg / L, preferably 1000-30000 mg / L, more preferably 5000-30000 mg / L; B / C is 0-0.3, preferably 0-0.2; the COD of the ammoximation industrial wastewater is 300-30000 mg / L, preferably 500-15000 mg / L, more preferably 3000-13000 mg / L; H 2 O 2 The content of the detected substance is 200-30000 mg / L, preferably 500-15000 mg / L, more preferably 3000-13000 mg / L; B / C is 0-0.3, preferably 0-0.2. Wherein B / C is the abbreviation of the ratio of BOD to COD, indicating the biodegradability of the wastewater. When B / C>0.3, the wastewater can be biodegraded. The organic wastewater disclosed in the present invention contains a large amount of refractory organic macromolecules, and the ammoximation industrial wastewater contains a large amount of H 2 O 2 The COD values ​​of these two types of wastewater are both above 1000 mg / L, and they contain substances that are toxic and harmful to microorganisms. Their B / C ratio is close to 0. They cannot be discharged directly into the sewage treatment system to avoid causing massive death of microorganisms.

[0025] In one embodiment of the present disclosure, the preparation method of the concentrated solution comprises: using a vacuum distillation method or a membrane concentration method to concentrate the ammoximation process wastewater to obtain the concentrated solution and fresh water; in a preferred embodiment, the volume of the concentrated solution is 1-10% of the volume of the ammoximation process wastewater. In the above embodiment, the selected concentration method is conducive to the removal of H in the ammoximation industrial wastewater. 2 O 2 The detected substances of various properties are concentrated in the concentrate, which increases the B / C value of the fresh water after concentration treatment, so that it can be directly fed into the company's existing sewage treatment plant for treatment.

[0026] In one embodiment of the present disclosure, the temperature of the reduced pressure distillation is 50-100°C, preferably 60-90°C; the time is 0.2-10h, preferably 0.5-5h; the vacuum degree is 0.01-0.1KPa, preferably 0.02-0.08KPa.

[0027] In one embodiment of the present disclosure, in one embodiment of the present disclosure, the conditions of the wet oxidation treatment include: a temperature of 80 to 400°C, preferably 100 to 300°C, more preferably 120 to 250°C; a pressure of 1.0 to 15MPa, preferably 1.5 to 10MPa, more preferably 2 to 7MPa; the wet oxidation treatment is carried out in a reactor, and the reactor includes a fixed bed reactor, a fluidized bed reactor or a kettle reactor. In the above embodiment, the selected wet oxidation treatment is conducive to reducing the COD value of the wastewater, increasing the B / C value, and thus improving its biodegradability.

[0028] In a preferred embodiment, the wet oxidation treatment is carried out in a fixed bed reactor, and the volume liquid hourly space velocity of the reaction is 0.05 to 30 h -1 , preferably 0.2 to 10 hours -1 In the above embodiment, the first catalyst and the second catalyst are contacted in a fixed bed reactor and effectively play a synergistic role to reduce the content of refractory organic matter in the wastewater and improve biodegradability.

[0029] In one embodiment of the present disclosure, the method further comprises: introducing an oxidizing gas into the mixed wastewater, wherein the amount of the oxidizing gas introduced is 1 to 3 times, preferably 1.05 to 1.5 times, the amount of oxidant required for the COD value in the mixed wastewater; preferably, the oxidizing gas comprises oxygen and / or air.

[0030] The present disclosure is further described in detail by examples. The raw materials used in the examples can be obtained through commercial channels. Among them, the determination method of BOD is the five-day biochemical method (HJ 505-2009), the determination method of COD is the potassium dichromate method (GB 11914-89), and B / C is the ratio of BOD to COD; the content of rare earth metals loaded on the carrier is tested by XRF analyzer, and the instrument model is Rigaku 3271E.

[0031] Example 1

[0032] (1) The COD of ammonia oxime industrial wastewater from a petrochemical plant is 3970 mg / L, and the total phosphorus concentration is 115 mg / L. 2 O 2The mass concentration of the detected substance is 6120mg / L, and B / C is 0.01; the ammoximation industrial wastewater is concentrated by vacuum distillation, the vacuum distillation temperature is 80℃, the time is 2h, the vacuum degree is 0.08KPa, and a concentrated solution with a volume of 5% of the ammoximation process wastewater and a fresh water with a volume of 95% of the ammoximation process wastewater are obtained, wherein the COD of the concentrated solution is 64150mg / L, and the H 2 O 2 The mass concentration of the detected substance is 120000mg / L, and the B / C ratio is 0.01; the COD of the fresh water is 800mg / L, and the B / C ratio is 0.65. The fresh water can be directly treated in the company's existing sewage treatment plant;

[0033] (2) The concentrated solution obtained in step (1) is mixed with organic wastewater (petrochemical wastewater from a petrochemical enterprise, with a COD of 18000 mg / L and a B / C ratio of 0.02) to obtain mixed wastewater. The COD in the mixed wastewater is 1.000 mg / L and the B / C ratio is 0.02. 2 O 2 The content ratio of the detected substances in the mixed wastewater is 1:0.4. 2 O 2 The content of the detected substance in the mixed wastewater is 9000 mg / L, ferrous sulfate (the first catalyst) is added to the mixed wastewater to make the content of ferrous sulfate in the mixed wastewater 2000 mg / L; the pH of the mixed wastewater is adjusted to 6 to obtain pre-oxidized mixed wastewater;

[0034] (3) Activated carbon loaded with metallic cerium (second catalyst) is filled in a stainless steel reactor of a small continuous fixed bed reactor. The content of metallic cerium in terms of cerium element is 0.8% by weight based on the total weight of the activated carbon, and the filling amount of the second catalyst in the reactor is 80%. The pre-oxidized mixed wastewater obtained in step (2) is sent to a fixed bed reactor for wet oxidation treatment, and air is introduced into the mixed wastewater at the same time. The amount of air introduced is 1.05 times the amount of oxidant required for the COD value in the mixed wastewater; wherein the temperature of the wet oxidation treatment is 160°C, the pressure is 2.9MPa, and the volume liquid hourly space velocity is 0.6h -1 , and obtain treated wastewater 1.

[0035] The COD value of the treated wastewater 1 is 3765 mg / L, and the B / C value is 0.33.

[0036] Example 2

[0037] The same as Example 1, the only difference is that in step (3), the temperature of the wet oxidation treatment is 200°C, and the treated wastewater 2 is obtained. The COD value of the treated wastewater 2 is 3346 mg / L, and the B / C value is 0.36.

[0038] Example 3

[0039] The same as Example 1, the only difference is that in step (3), the amount of air introduced is 1.1 times the amount of oxidant required for the COD value in the mixed wastewater, the pressure of the wet oxidation treatment is 3.04 MPa, and treated wastewater 3 is obtained. The COD value of the treated wastewater 3 is 3031 mg / L, and the B / C value is 0.37.

[0040] Example 4

[0041] The same as Example 1, except that in step (3), the volume liquid hourly space velocity of the wet oxidation treatment is 0.4h -1 , and obtained treated wastewater 4. The COD value of treated wastewater 4 was 3526 mg / L, and the B / C value was 0.35.

[0042] Example 5

[0043] The same as Example 1, except that: the mixed wastewater in step (2) is H 2 O 2 The content of the detected substance was 18000 mg / L, and the treated wastewater 5 was obtained. The COD value of the treated wastewater 5 was 2637 mg / L, and the B / C value was 0.41.

[0044] Example 6

[0045] The method is the same as Example 1, except that in step (2), the content of ferrous sulfate in the mixed wastewater is 10000 mg / L, and treated wastewater 6 is obtained. The COD value of the treated wastewater 6 is 2351 mg / L, and the B / C value is 0.42.

[0046] Example 7

[0047] The same as Example 1, the only difference is that in step (3), the second catalyst is activated carbon loaded with metallic lanthanum, and the content of metallic lanthanum calculated as lanthanum element is 1 wt% based on the total weight of the activated carbon, to obtain treated wastewater 7, the COD value of the treated wastewater 7 is 4052 mg / L, and the B / C value is 0.32.

[0048] Example 8

[0049] The same as Example 1, the only difference is that: in step (1), the volume of the concentrated solution is 0.5% of the volume of the ammoximation process wastewater, the COD of the obtained ammoximation fresh water is 1500 mg / L, and the B / C is 0.21; in step (2), the concentrated solution is mixed with organic wastewater, and the COD and B / C of the obtained mixed wastewater are 0.1% and 0.2% respectively. 2 O 2 The content ratio of the detected substances in the mixed wastewater is 1:0.37. 2 O 2The content of the detected substance was 8500 mg / L, and the treated wastewater 8 was finally obtained. The COD value of the treated wastewater 8 was 3975 mg / L, and the B / C value was 0.32.

[0050] Example 9

[0051] The same as Example 1, except that: in step (2), COD in the mixed wastewater is mixed with H 2 O 2 The content ratio of the detected objects was 1:5, and the treated wastewater 9 was obtained. The COD value of the treated wastewater 9 was 2780 mg / L, and the B / C value was 0.31.

[0052] Example 10

[0053] The same as Example 1, except that: in step (2), COD in the mixed wastewater is mixed with H 2 O 2 The content ratio of the detected objects was 1:8, and the treated wastewater 10 was obtained. The COD value of the treated wastewater 10 was 2570 mg / L, and the B / C value was 0.26.

[0054] Embodiment 11

[0055] The method is the same as Example 1, except that step (1) is not performed, and the concentrated solution of ammonia oximation process wastewater is not added to the organic wastewater in step (2), thereby obtaining treated wastewater 11, and the COD value of the treated wastewater 11 is 4762 mg / L, and the B / C value is 0.28.

[0056] Example 12

[0057] The method is the same as Example 1, except that step (1) is not performed, and the concentrated solution of ammonia oxime process wastewater is not added to the organic wastewater in step (2). Instead, hydrogen peroxide (mass fraction of 12%) with the same volume as the concentrated solution is mixed with the organic wastewater to obtain treated wastewater 12. The COD value of the treated wastewater 12 is 4325 mg / L, and the B / C value is 0.29.

[0058] Embodiment 13

[0059] The method is the same as Example 1, except that step (1) is not performed, the concentrated solution of ammonia oxime process wastewater is not added to the organic wastewater in step (2), the pH of the organic wastewater is adjusted to 7.5, and treated wastewater 13 is obtained. The COD value of the treated wastewater 13 is 4749 mg / L, and the B / C value is 0.28.

[0060] Embodiment 14

[0061] The method is the same as Example 1, except that step (1) is not performed, the concentrated solution of ammoximation process wastewater is not added to the organic wastewater in step (2), the content of ferrous sulfate in the organic wastewater is 10000 mg / L, and treated wastewater 14 is obtained. The COD value of the treated wastewater 14 is 5107 mg / L, and the B / C value is 0.26.

[0062] Embodiment 15

[0063] The method is the same as Example 1, except that step (1) is not performed, and the concentrated solution of ammoximation process wastewater is not added to the organic wastewater in step (2). Instead, hydrogen peroxide (mass fraction: 12%) having the same volume as the concentrated solution is mixed with the organic wastewater, and the content of ferrous sulfate in the mixed solution is 10000 mg / L. Treated wastewater 15 is obtained, and the COD value of the treated wastewater 15 is 4128 mg / L, and the B / C value is 0.3.

[0064] Comparative Example 1

[0065] The method is the same as Example 1, except that in step (2), ferrous sulfate is not added to the mixed wastewater (i.e., the first catalyst is not added), and comparative treated wastewater 1 is obtained. The COD value of comparative treated wastewater 1 is 8846 mg / L, and the B / C value is 0.21.

[0066] Comparative Example 2

[0067] The method is the same as Example 1, except that the content of ferrous sulfate in the mixed wastewater of step (2) is 10000 mg / L; the fixed bed reactor of step (3) is not filled with a carrier loaded with metallic cerium (i.e., no second catalyst is added), and comparative treated wastewater 2 is obtained. The COD value of the comparative treated wastewater 2 is 6843 mg / L, and the B / C value is 0.23.

[0068] Comparative Example 3

[0069] The method is the same as Example 1, except that ferrous sulfate and ferric sulfate are added to the mixed wastewater obtained in step (2) as a mixed catalyst, the weight ratio of ferrous sulfate to ferric sulfate is 1:1, and the content of the mixed catalyst in the mixed wastewater is 4000 mg / L; the fixed bed reactor in step (3) is not filled with a carrier loaded with metallic cerium (i.e., no second catalyst is added), and comparative treated wastewater 3 is obtained. The COD value of the comparative treated wastewater 3 is 5370 mg / L, and the B / C value is 0.24.

[0070] Comparative Example 4

[0071] The same as Example 1, the only difference is that in step (2), the pH of the mixed wastewater is adjusted to 7.5 to obtain treated wastewater 13, the COD value of the treated wastewater 13 is 6832 mg / L, and the B / C value is 0.23.

[0072] From the above results, it can be seen that compared with Comparative Examples 1 to 3, Examples 1 to 15 use a homogeneous transition metal salt and a heterogeneous rare earth metal-loaded carrier as a mixed catalyst, which can effectively reduce the content of refractory organic matter in organic wastewater when used for wet oxidation treatment of organic wastewater, improve biodegradability, and make the treated wastewater have a lower COD value and a higher B / C value, which can be directly discharged to a sewage treatment plant. Comparative Examples 1 to 3 do not use the first catalyst and the second catalyst at the same time, and the COD value of the treated wastewater is higher and the B / C value is lower (<0.25), that is, the biodegradability is poor, and it is not suitable to be directly discharged to a sewage treatment plant.

[0073] The preferred embodiments of the present disclosure are described in detail above; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0074] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0075] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for treating organic wastewater by wet oxidation, characterized in that: The method comprises: performing wet oxidation treatment on organic wastewater in the presence of a catalyst; The catalyst includes a first catalyst and a second catalyst, the first catalyst includes a soluble transition metal salt, and the second catalyst includes a carrier and a rare earth metal supported on the carrier.

2. The method according to claim 1, characterized in that The method comprises: mixing the organic wastewater and the concentrated solution of the ammoximation process wastewater to obtain mixed wastewater; adjusting the pH of the mixed wastewater to below 6, and performing the wet oxidation treatment.

3. The method according to claim 2, characterized in that The soluble transition metal salt is selected from one or more of a soluble iron salt, a soluble cobalt salt, a soluble nickel salt and a soluble platinum salt, preferably a soluble iron salt, more preferably ferrous sulfate; The content of soluble transition metal salt in the mixed wastewater is 100-12000 mg / L, preferably 500-11000 mg / L, and more preferably 3000-10000 mg / L.

4. The method according to claim 1, characterized in that The carrier is selected from one or more of activated carbon, molecular sieve and activated coke, preferably activated carbon; the rare earth metal is selected from cerium and / or lanthanum, preferably cerium; Based on the total weight of the carrier, the content of the rare earth metal in terms of metal element is 0.2 to 5% by weight, preferably 0.3 to 4% by weight.

5. The method according to claim 2, characterized in that: The ratio of COD to the detected substance in terms of H2O2 in the mixed wastewater is 1:(0.1-5), preferably 1:(0.3-2); the content of the detected substance in terms of H2O2 is 300-22000 mg / L, preferably 1000-20000 mg / L, and more preferably 10000-18000 mg / L.

6. The method according to claim 2, characterized in that The COD of the organic wastewater is 500-50000 mg / L, preferably 1000-30000 mg / L; B / C is 0-0.3, preferably 0-0.2; The COD of the ammoximation industrial wastewater is 300-30000 mg / L, preferably 500-15000 mg / L; the content of the detected substance calculated as H2O2 is 200-30000 mg / L, preferably 500-15000 mg / L; B / C is 0-0.3, preferably 0-0.

2.

7. The method according to claim 2, characterized in that The preparation method of the concentrated solution comprises: concentrating the ammoximation process wastewater by vacuum distillation or membrane concentration to obtain the concentrated solution and fresh water; preferably, the volume of the concentrated solution is 1-10% of the volume of the ammoximation process wastewater.

8. The method according to claim 7, characterized in that The temperature of the reduced pressure distillation is 50-100° C., preferably 60-90° C.; the time is 0.2-10 h, preferably 0.5-5 h; the vacuum degree is 0.01-0.1 KPa, preferably 0.02-0.08 KPa.

9. The method according to claim 1 or 2, characterized in that: The conditions of the wet oxidation treatment include: a temperature of 80 to 400° C., preferably 100 to 300° C., more preferably 120 to 250° C.; a pressure of 1.0 to 15 MPa, preferably 1.5 to 10 MPa, more preferably 2 to 7 MPa; The wet oxidation treatment is carried out in a reactor, which includes a fixed bed reactor, a fluidized bed reactor or a tank reactor; Preferably, the wet oxidation treatment is carried out in a fixed bed reactor, and the reaction volume liquid hourly space velocity is 0.05 to 30 h -1 , preferably 0.2 to 10 hours -1 .

10. The method according to claim 2, characterized in that The method further comprises: introducing an oxidizing gas into the mixed wastewater, wherein the amount of the oxidizing gas introduced is 1 to 3 times, preferably 1.05 to 1.5 times, the amount of oxidant required for the COD value in the mixed wastewater; Preferably, the oxidizing gas comprises oxygen and / or air.