Wastewater treatment method based on improved wet oxidation reaction

Abstract

The invention discloses a wastewater treatment method based on improved wet oxidation reaction, which comprises the following steps: step 1, carrying out tempering modification treatment on wastewater, and preheating by adopting a multi-stage heat exchanger; 2, introducing the preheated wastewater and an oxidizing agent into a wet oxidation tower filled with a solid catalyst, and gradually heating to a required reaction temperature to carry out a wet oxidation reaction; 3, carrying out gas-liquid separation on a gas-liquid mixture flowing out of the wet oxidation tower, feeding the separated gas phase and liquid phase into the multi-stage heat exchanger in the step 1, carrying out heat exchange with the wastewater in the step 1, and preheating the wastewater to raise the temperature; and step 4, separating the cooled gas phase and liquid phase again, feeding the separated gas phase into the wastewater in the step 1 to carry out tempering modification on the wastewater, and further carrying out deep treatment or discharging the separated liquid phase. The method can effectively degrade organic pollutants in wastewater, and is low in energy consumption and operation cost and stable in process operation.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and specifically relates to a wastewater treatment method based on an improved wet oxidation reaction. Background Art

[0002] High-concentration organic wastewater mainly comes from the pesticide, medicine, coking, dye, printing and dyeing, petrochemical, leather and other industries. It usually contains hydrocarbons, oils, organic sulfur, inorganic sulfur and other substances. This type of wastewater has the characteristics of complex components, stable structure, and is difficult to degrade by biochemical or physical and chemical methods.

[0003] At present, the most recognized effective technology for treating high-concentration organic wastewater is wet oxidation reaction technology, which uses air, ozone, pure oxygen or hydrogen peroxide as oxidants under high temperature and high pressure conditions to oxidize dissolved or suspended organic matter or reduced inorganic matter in water to generate CO2 and small molecules to purify wastewater. Compared with other traditional treatment methods, wet oxidation technology has the characteristics of wide application range, high treatment efficiency, fast oxidation rate, recyclable energy and useful materials, and less secondary pollution. Therefore, it has been widely valued by researchers from all over the world and is a very promising water treatment method.

[0004] At present, wet oxidation technology is relatively mature, but it still has some disadvantages:

[0005] 1. When wet oxidation is used to treat high-concentration, hard-to-degrade organic wastewater, the reaction temperature is usually 200°C and the pressure is 5-6MPa, so the range of wastewater that can be treated is narrow;

[0006] 2. The concentration range of organic matter in the influent is limited, the influent COD is generally controlled within 60000mg / L, and the types of wastewater that can be treated are limited;

[0007] 3. When treating organic wastewater, the COD degradation rate is low, and the conversion rate of difficult-to-biodegrade macromolecules into easily biodegradable small molecules is low;

[0008] 4. Wet oxidation reaction needs to be carried out under high temperature and pressure conditions, with high energy consumption and operating costs;

[0009] 5. During the wastewater treatment process, organic matter in the wastewater can easily scale and clog the heat exchanger and heater, resulting in low heat exchange and heating efficiency, and the process cannot operate continuously and stably.

[0010] Therefore, the application of wet oxidation technology in the field of high-concentration organic wastewater treatment is limited. In order to overcome the problems existing in the above-mentioned prior art, a high-salt, high-organic and high-toxicity wastewater treatment technology with a wide range of applications, high COD removal rate, low energy consumption and operating costs, and stable process operation is needed. Summary of the invention

[0011] Purpose of the invention: In view of the problems existing in the prior art, the present invention provides a wastewater treatment method based on an improved wet oxidation reaction. For high-concentration, difficult-to-degrade wastewater, the improved wet oxidation reaction technology of the present invention has a wide range of applications, high COD removal rate, low energy consumption and operating costs, and stable process operation. It can effectively degrade organic pollutants in wastewater, improve the biodegradability of wastewater, and ultimately achieve the purpose of meeting wastewater discharge standards.

[0012] Technical solution: To achieve the above purpose, the present invention adopts the following technical solution:

[0013] A wastewater treatment method based on improved wet oxidation reaction comprises the following steps:

[0014] Step 1, after the wastewater is subjected to conditioning and modification treatment, it is preheated using a multi-stage heat exchanger;

[0015] Step 2, the preheated wastewater and the oxidant are introduced into a wet oxidation tower containing a solid catalyst, and the temperature is gradually raised to the required reaction temperature to carry out a wet oxidation reaction;

[0016] Step 3, separating the gas-liquid mixture flowing out of the wet oxidation tower, and the separated gas phase and liquid phase both enter the multi-stage heat exchanger described in step 1, and after heat exchange with the wastewater in step 1, the wastewater is preheated and the gas phase and liquid phase form a gas-liquid mixture again;

[0017] Step 4, the gas-liquid mixture after heat exchange is separated again, the separated gas phase enters the wastewater in step 1 to condition and modify the wastewater, and the separated liquid phase is further deeply treated or discharged.

[0018] As a specific implementation scheme, in step 1, the wastewater is wastewater from pesticides, medicine, coking, dyes, printing and dyeing, petrochemicals or leather and other fields with an inlet COD concentration of less than 100,000 mg / L.

[0019] As a specific implementation scheme, in step 1, the multi-stage heat exchanger is a plurality of heat exchangers arranged in series; after the preheating, the wastewater temperature reaches 180-200°C, so that the temperature rise during the final heating is reduced, thereby reducing the operating energy consumption.

[0020] As a specific implementation scheme, in step 2, the oxidant is selected from air; the temperature of the wet oxidation reaction is 200-260°C, the reaction pressure is 2-8MPa, the reaction temperature and pressure can be adjusted in real time according to the raw water concentration and the reaction process, and the reaction residence time is 40-60min.

[0021] As a specific implementation scheme, in step 2, the solid catalyst is a metal oxide supported catalyst, the metal oxide is coated by a carrier, and can be screened for various organic substances with different structures in sewage; preferably, the metal combination supported on the carrier includes CuO-MnO-CeO, FeO-CuO-MnO or CuO-ZnO-CeO, and the carrier is a TiO2 carrier. The solid catalyst has good anti-loss performance, short reaction residence time, wastewater COD removal rate of more than 90%, and the biodegradability B / C of the wastewater after oxidation is increased to more than 0.4.

[0022] As a specific implementation scheme, in step 2, the gradual temperature increase is to divide the wet oxidation tower into a low-temperature reaction zone and a high-temperature reaction zone, wherein the temperature of the low-temperature reaction zone is 200-240°C, and the temperature of the high-temperature zone is 220-260°C. The wastewater enters the wet oxidation reaction tower and passes through the low-temperature zone and the high-temperature zone in turn, and gradually increases the temperature to the final reaction temperature. The temperature rise is reduced to ensure the safety of the system.

[0023] As a specific implementation scheme, in step 3, the gas-liquid separation adopts a high-pressure gas-liquid separator.

[0024] As a specific implementation scheme, in step 4, the gas-liquid separation adopts a low-pressure gas-liquid separator.

[0025] As a specific implementation scheme, in step 4, the main component of the wastewater after wet oxidation is small molecule acid, which is easy to be biochemically treated; the deep treatment includes using A / O, SBR or MBR biochemical treatment technology to further remove organic pollutants in the wastewater.

[0026] In the method of the present invention, organic matter in the wastewater is oxidized during the wet oxidation reaction, and a large amount of heat is released by the reaction to maintain a constant temperature of the mixed liquid. A multi-stage heat exchanger is used to recover the heat. After the high-temperature material discharged from the wet oxidation tower is separated, the gas phase and the liquid phase flow through the multi-stage heat exchanger in sequence, and the inlet liquid is preheated and heated to form a reaction cycle. The multi-stage preheating reduces the temperature rise during the final heating, reduces energy consumption and costs, and the gas phase and liquid phase entering the multi-stage heat exchanger form a gas-liquid mixture again. Finally, the gas phase separated again by the low-pressure gas-liquid separator of the gas-liquid mixture is passed into the original wastewater storage tank to realize the recovery and utilization of the pressure and residual oxygen in the gas after the reaction, reduce energy consumption and costs, and at the same time, the gas phase generated by the reaction is rich in CO2, and the volume percentage of CO2 accounts for about 20%-80%, which can react chemically with the salts in the original wastewater to generate bicarbonate, which has the function of reducing system scaling, realizes the conditioning and modification of the original wastewater, and ensures the stable operation of the process.

[0027] Beneficial effects: Compared with the prior art, the method of the present invention is applicable to wastewater in multiple fields and has a wide range of applications. The use of multi-metal oxide supported catalysts can effectively degrade organic pollutants in wastewater, and the biodegradability and treatment efficiency of wastewater are high. In addition, by preheating the inlet of the wet oxidation tower in multiple stages and gradually raising the temperature, and recycling the large amount of heat released by the oxidation reaction and the pressure and residual oxygen in the gas after the reaction, the energy consumption and operating costs are reduced, and the safe operation of the system is guaranteed. At the same time, the CO2-rich gas phase generated by the reaction reacts chemically with the salts in the raw wastewater to generate bicarbonate, which has the function of reducing system scaling, realizing the conditioning and modification of the raw wastewater, and the process operation is stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of the wet oxidation process provided by the present invention for treating high-salt, high-organic and high-toxic wastewater. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with specific examples, but the present invention is not limited to the following examples. The experimental methods used in the examples are conventional methods unless otherwise specified, and the materials and reagents used are all commercially available unless otherwise specified.

[0030] An improved wet oxidation reaction technology specifically comprises the following steps:

[0031] Step 1: After the high-salt, high-organic and high-toxic wastewater is tempered and modified, it is sent to the preheating system for heat exchange with the hot material from the reactor. The preheating system adopts a multi-stage heat exchanger. The wastewater undergoes a multi-stage preheating and heating process. After the multi-stage heat exchanger, the wastewater temperature can reach 180-200°C, which reduces the temperature rise during the final heating and the operating energy consumption is lower than that of the conventional wet oxidation process.

[0032] Step 2: The high-salt, high-organic, and high-toxic wastewater after heating is passed together with the oxidant into a wet oxidation device equipped with a solid catalyst and gradually heated to the required reaction temperature for high-temperature treatment. The wet oxidation reaction temperature is 200-260°C, wherein the temperature in the low temperature zone of the wet oxidation reactor can be raised to about 200-240°C, and the temperature in the high temperature zone of the wet oxidation reactor can be raised to 220-260°C. The reaction pressure of the wet oxidation reactor is 2-8MPa. The reaction temperature and pressure can be adjusted in real time according to the raw water concentration and the reaction process. The reaction residence time is 40-60min, and the oxidant is air during the reaction.

[0033] The solid catalyst selects a multi-metal oxide composite catalyst, which mainly utilizes the structure, morphology, electronic state, etc. of a variety of rare earth metal oxides (FeO, MnO, CeO, CuO, ZnO) to make them fully contact with the carrier, increase the surface area and active sites of the catalyst, have higher catalytic activity, and efficiently degrade organic pollutants. At the same time, it is beneficial to reduce the dissolution of metal ions, extend the service life of the catalyst, and save costs. The details are as follows:

[0034] Mn-based oxides have a variety of oxidation states and crystal structures, showing unique redox properties. 4+ / Mn 3+ ) during the redox cycle and oxygen activation process, which is beneficial to the utilization of surface oxygen and the activation of gaseous oxygen during the wet oxidation process.

[0035] Cu-based composite oxides have high catalytic activity, but have the disadvantage of copper ion loss after repeated use. However, they can improve catalytic activity when interacting with other metals, and the dissolution amount is extremely small.

[0036] Fe-based oxides have good oxidizability, high selectivity and high reaction rate. The physicochemical properties of Fe-based oxide catalysts are stable, they are very insensitive to moisture and even water vapor, and they are non-biotoxic. They are widely used in the field of catalytic oxidation.

[0037] Zn-based oxides mainly utilize the active sites on the surface of zinc oxide molecules to promote chemical reactions between reactant molecules. They have a high surface area and porosity, good chemical stability and thermal stability. The crystal structure of the zinc oxide catalyst is highly controllable and can be regulated according to the needs of the oxidation reaction system.

[0038] As an electronic auxiliary agent, Ce can interact with other metals to promote the generation of active metal sites and other active oxidants to produce active free radicals, thereby improving the catalytic performance of the catalyst. At the same time, the doping of metal ions can cause changes between the crystal lattices of Ce-based catalysts, thereby increasing the mobility of oxygen anions, enhancing the ability of Ce-based catalysts to store and release oxygen, and effectively improving the catalytic performance of Ce-based catalysts.

[0039] (1) CuO-MnO-CeO catalyst

[0040] The addition of Mn promotes the dispersion of Cu species, making the grain size more uniform, and improving the activity and selectivity of the catalyst. The introduction of Ce can adjust the ratio of Cu and Mn ions on the catalyst surface. The synergistic effect between Cu, Mn and Ce can improve the catalytic activity, and the dissolution amount is very small. The CuO-MnO-CeO catalyst uses a compound with a special regular structure as a precursor, and the interaction between the elements of the composite oxide forms a significant improvement in the catalytic performance and stability of the catalyst.

[0041] (2) FeO-CuO-MnO type catalyst

[0042] Loading both iron and copper metals onto the carrier at the same time can improve the stability of iron and the activity of copper. The addition of copper can not only improve the catalytic activity of iron-based catalysts, but also reduce the dependence on pH, so that the pH of the treated wastewater is maintained in a milder range, reducing the amount of reagents added and corrosion to equipment. In addition, by adding metallic manganese, the surface of the catalyst can be transformed from crystalline to amorphous. The FeO-CuO-MnO type catalyst has high surface area, thermal stability, mechanical strength and chemical stability, and the catalyst has strong catalytic properties.

[0043] (3) CuO-ZnO-CeO type catalyst

[0044] The working principle of CuO-ZnO-CeO catalyst is based on the adsorption and catalytic effect of zinc oxide on reactants, and provides active sites for the reaction. The addition of copper oxide plays a role in regulating the reaction rate and improving the stability of the catalyst. The incorporation of Ce can effectively improve the dispersion of copper and zinc metals on the carrier surface. CuO-ZnO-CeO catalyst has strong activity.

[0045] The catalyst carrier is TiO2 because it has good stability under acidic and alkaline conditions and is relatively cheap. The metal oxide is coated by the TiO2 carrier, the catalyst has strong catalytic activity and good anti-loss performance, and can efficiently degrade organic pollutants in wastewater.

[0046] Step 3: During the wet oxidation reaction, the organic matter in the wastewater is oxidized. The gas-liquid mixture flowing out of the wet oxidation tower contains high concentrations of gas and steam. Directly entering the heat exchanger may cause excessive pressure in the equipment, thereby damaging the heat exchanger or other related equipment. The gas-liquid separation can control the fluid pressure entering the heat exchanger to protect the equipment from damage.

[0047] At the same time, it can ensure that the fluid entering the heat exchanger has a high purity, avoiding blockage of the heat exchanger or a decrease in heat transfer efficiency. After the high-temperature material discharged from the wet oxidation tower is separated by the high-pressure gas-liquid separator, the gas phase and the liquid phase enter the multi-stage heat exchanger in turn, preheating the inlet liquid of the wet oxidation tower to form a reaction cycle, so that the temperature rise during the final heating is reduced, heat recovery is achieved during the reaction process, and energy consumption and costs are reduced; the gas phase and liquid phase entering the multi-stage heat exchanger form a gas-liquid mixture again.

[0048] Step 4, the gas-liquid mixture after heat exchange enters the low-pressure gas-liquid separation device for gas-liquid separation again, and the resulting liquid phase enters the deep treatment unit for further treatment or discharge. The deep treatment unit includes the use of A / O, SBR, MBR and other biochemical treatment technologies to further remove organic pollutants in the wastewater; the resulting gas phase enters the raw wastewater storage tank to realize the recovery and utilization of the pressure and residual oxygen in the gas after the reaction. The scale of high-salt, high-organic and high-toxic organic wastewater under high temperature conditions is mainly a composite scale composed of calcium carbonate and magnesium carbonate. The volume percentage of CO2 in the reaction gas phase of the wet oxidation tower is about 20%-80%. The CO2-rich reaction gas is introduced into the raw water storage tank, and CO2 reacts with carbonate in the wastewater to generate bicarbonate, which can achieve the effect of anti-scaling and anti-clogging, realize the conditioning and modification of the raw wastewater, and ensure the stable operation of the process.

[0049] When the present invention is actually used, it can treat wastewater from pesticides, medicine, coking, dyes, printing and dyeing, petrochemicals, leather, etc.

[0050] Example 1

[0051] The mixed wastewater of pesticide intermediates produced in the production process of a pesticide enterprise mainly contains o-nitrophenol and p-hydroxyphenoxypropionic acid. The wastewater volume is 100m 3 / d, the influent COD concentration is 98000 mg / L, B / C is 0.2, and deep oxidation is carried out using the improved wet oxidation reaction technology provided by the present invention, specifically comprising the following steps:

[0052] 1. After the high-salt, high-organic and high-toxic wastewater in the raw water storage tank is conditioned and modified, it is sent to the preheating system for heat exchange with the hot material from the reactor and gradually heated to 200°C through a multi-stage heat exchanger;

[0053] 2. The pressurized and heated high-salt, high-organic, and high-toxic wastewater and the oxidant are passed together into a wet oxidation device equipped with a solid catalyst for high-temperature treatment. The temperature of the low-temperature zone of the wet oxidation reactor is raised to 220°C, and the temperature of the high-temperature zone of the wet oxidation reactor is raised to 260°C. The pressure in the reactor is 8MPa, the oxidant is compressed air, and the added catalyst is a CuO-MnO-CeO loaded type. The catalyst addition amount accounts for 2.5% of the wastewater mass, and the catalyst and the oxidant react for 60 minutes;

[0054] 3. During the reaction, the organic matter in the wastewater is oxidized, and the reaction releases a large amount of heat to keep the temperature of the mixed liquid constant. The high-temperature and high-pressure materials flowing out of the reactor are treated by the high-pressure gas-liquid separation device and then enter the multi-stage heat exchanger for cooling. The heat in the reaction process is recovered and reused for wastewater preheating;

[0055] 4. The cooled liquid enters the low-pressure gas-liquid separation device, the resulting liquid phase enters the deep treatment unit for further treatment or discharge, and the resulting gas phase enters the raw water storage tank. The pressure and residual oxygen in the gas after the reaction are recycled, and the raw wastewater is conditioned and modified at the same time to reduce the risk of system scaling.

[0056] After testing, the COD concentration of the treated organic wastewater was 7336 mg / L, the COD removal rate reached 92.51%, and the effluent B / C was 0.41.

[0057] Example 2

[0058] A chemical company producing coatings and resins discharged high-concentration organic wastewater with a COD concentration of 80,000 mg / L and a wastewater volume of 125 m 3 / d, B / C is 0.24, and deep oxidation is carried out using the improved wet oxidation reaction technology provided by the present invention, which specifically includes the following steps:

[0059] 1. After the high-salt, high-organic and high-toxic wastewater in the raw water storage tank is conditioned and modified, it is sent to the preheating system for heat exchange with the hot material from the reactor and gradually heated to 200°C through a multi-stage heat exchanger;

[0060] 2. The pressurized and heated high-salt, high-organic, and high-toxic wastewater and the oxidant are passed together into a wet oxidation device equipped with a solid catalyst for high-temperature treatment. The temperature of the low-temperature zone of the wet oxidation reactor is raised to 220°C, and the temperature of the high-temperature zone of the wet oxidation reactor is raised to 260°C. The pressure in the reactor is 7MPa, the oxidant is compressed air, and the added catalyst is a FeO-CuO-MnO loaded type. The catalyst addition amount accounts for 2% of the wastewater mass, and the catalyst and the oxidant react for 50 minutes;

[0061] 3. During the reaction, the organic matter in the wastewater is oxidized, and the reaction releases a large amount of heat to keep the temperature of the mixed liquid constant. The high-temperature and high-pressure materials flowing out of the reactor are treated by the high-pressure gas-liquid separation device and then enter the multi-stage heat exchanger for cooling. The heat in the reaction process is recovered and reused for wastewater preheating;

[0062] 4. The cooled liquid enters the low-pressure gas-liquid separation device, the resulting liquid phase enters the deep treatment unit for further treatment or discharge, and the resulting gas phase enters the raw water storage tank. The pressure and residual oxygen in the gas after the reaction are recycled, and the raw wastewater is conditioned and modified at the same time to reduce the risk of system scaling.

[0063] After testing, the COD concentration of the treated organic wastewater was 7200 mg / L, the COD removal rate reached 91%, and the effluent B / C was 0.4.

[0064] Example 3

[0065] The COD concentration of the waste lye produced by a petrochemical enterprise is 67500 mg / L, and the wastewater volume is 1.5 m 3 / h, deep oxidation is carried out using the improved wet oxidation reaction technology provided by the present invention, specifically comprising the following steps:

[0066] 1. After the high-salt, high-organic and high-toxic wastewater in the raw water storage tank is conditioned and modified, it is sent to the preheating system for heat exchange with the hot material from the reactor and gradually heated to 200°C through a multi-stage heat exchanger;

[0067] 2. The pressurized and heated high-salt, high-organic, and high-toxic wastewater and the oxidant are passed together into a wet oxidation device equipped with a solid catalyst for high-temperature treatment. The temperature of the low-temperature zone of the wet oxidation reactor is raised to 220°C, and the temperature of the high-temperature zone of the wet oxidation reactor is raised to 250°C. The pressure in the reactor is 7MPa, the oxidant is compressed air, and the added catalyst is a FeO-CuO-MnO loaded type. The catalyst addition amount accounts for 2% of the wastewater mass, and the catalyst and the oxidant react for 45 minutes;

[0068] 3. During the reaction, the organic matter in the wastewater is oxidized, and the reaction releases a large amount of heat to keep the temperature of the mixed liquid constant. The high-temperature and high-pressure materials flowing out of the reactor are treated by the high-pressure gas-liquid separation device and then enter the multi-stage heat exchanger for cooling. The heat in the reaction process is recovered and reused for wastewater preheating;

[0069] 4. The cooled liquid enters the low-pressure gas-liquid separation device, the resulting liquid phase enters the deep treatment unit for further treatment or discharge, and the resulting gas phase enters the raw wastewater storage tank. The pressure and residual oxygen in the gas after the reaction are recycled, and the raw wastewater is conditioned and modified at the same time to reduce the risk of system scaling.

[0070] After testing, the COD concentration of the treated organic wastewater was 5200 mg / L, the COD removal rate reached 92.3%, and the effluent B / C was 0.4.

[0071] The above embodiments are the best implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A wastewater treatment method based on improved wet oxidation reaction, characterized in that: The following steps are involved: Step 1, after the wastewater is subjected to conditioning and modification treatment, it is preheated using a multi-stage heat exchanger; Step 2, the preheated wastewater and the oxidant are introduced into a wet oxidation tower containing a solid catalyst, and the temperature is gradually raised to the required reaction temperature to carry out a wet oxidation reaction; Step 3, separating the gas-liquid mixture flowing out of the wet oxidation tower, and the separated gas phase and liquid phase both enter the multi-stage heat exchanger described in step 1, and after heat exchange with the wastewater in step 1, the wastewater is preheated and the gas phase and liquid phase form a gas-liquid mixture again; Step 4, the gas-liquid mixture after heat exchange is separated again, the separated gas phase enters the wastewater in step 1 to condition and modify the wastewater, and the separated liquid phase is further deeply treated or discharged.

2. The wastewater treatment method based on improved wet oxidation reaction according to claim 1, characterized in that: In step 1, the wastewater is wastewater from the pesticide, pharmaceutical, coking, dye, printing and dyeing, petrochemical or leather fields with an influent COD concentration of less than 100,000 mg / L.

3. The wastewater treatment method based on improved wet oxidation reaction according to claim 1, characterized in that: In step 1, the multi-stage heat exchanger is a plurality of heat exchangers arranged in series; the wastewater temperature reaches 180-200°C after the preheating.

4. The wastewater treatment method based on improved wet oxidation reaction according to claim 1, characterized in that: In step 2, the oxidant is selected from air; the temperature of the wet oxidation reaction is 200-260° C., the reaction pressure is 2-8 MPa, and the reaction residence time is 40-60 min.

5. The wastewater treatment method based on improved wet oxidation reaction according to claim 1, characterized in that: In step 2, the solid catalyst is a metal oxide supported catalyst, and the metal oxide is coated by a carrier; preferably, the metal combination supported on the carrier includes CuO-MnO-CeO, FeO-CuO-MnO or CuO-ZnO-CeO, and the carrier is a TiO2 carrier.

6. The wastewater treatment method based on improved wet oxidation reaction according to claim 1, characterized in that: In step 2, the gradual temperature increase is to divide the wet oxidation tower into a low-temperature reaction zone and a high-temperature reaction zone, wherein the temperature of the low-temperature reaction zone is 200-240°C, and the temperature of the high-temperature zone is 220-260°C. The wastewater enters the wet oxidation reaction tower and passes through the low-temperature zone and the high-temperature zone in turn, and gradually increases the temperature to the final reaction temperature.

7. The wastewater treatment method based on improved wet oxidation reaction according to claim 1, characterized in that: In step 3, the gas-liquid separation adopts a high-pressure gas-liquid separator.

8. The wastewater treatment method based on improved wet oxidation reaction according to claim 1, characterized in that: In step 4, the gas-liquid separation adopts a low-pressure gas-liquid separator.

9. The wastewater treatment method based on improved wet oxidation reaction according to claim 1, characterized in that: In step 4, the deep treatment includes using A / O, SBR or MBR biochemical treatment technology to further remove organic pollutants in the wastewater.

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