A microwave-coupled Fenton catalytic oxidation system for treating recalcitrant organic wastewater

Abstract

This utility model discloses a microwave-coupled Fenton catalytic oxidation system for treating recalcitrant organic wastewater, belonging to the field of wastewater treatment technology. It includes a reactor tank with an inlet pipe at the bottom and an outlet pipe at the top on one side. A circulation pipe is located on the other side, connected to a hydrogen peroxide storage tank via a hydrogen peroxide pipe. A ferrous pipe is installed above the inlet pipe, connected to a ferrous storage tank. A microwave generator is mounted on the top of the reactor tank, connected to a microwave transmitting antenna, which is protected by a PP sleeve. A pH meter and a temperature sensor are installed on both sides of the microwave generator and on the top of the reactor tank. The treated wastewater is mixed with hydrogen peroxide and introduced into the reactor tank through the circulation pipe, preventing the hydrogen peroxide from being prematurely consumed by mixing with highly concentrated wastewater. The temperature sensor reading is compared with a set temperature, and a PLC controller controls the microwave generator to reduce or stop irradiation, preventing excessively high temperatures from accelerating the Fenton side reaction.

Description

Technical Field

[0001] This utility model belongs to the field of wastewater treatment technology, specifically relating to a microwave-coupled Fenton catalytic oxidation system for treating recalcitrant organic wastewater. Background Technology

[0002] The statements in this section are merely background information related to this utility model and do not necessarily constitute prior art.

[0003] Currently, most industrial wastewater treatment processes employ advanced oxidation technologies for pretreatment. This process breaks down and breaks down recalcitrant macromolecular organic pollutants, converting them into simpler, smaller molecules for further treatment until the effluent meets standards. Fenton oxidation is a common advanced oxidation technology in industrial wastewater treatment; it is technically mature, simple to operate, and relatively easy to treat secondary waste. Fenton oxidation operates in an environment with a pH less than 3.5, using Fe... 2+ As a catalyst, it catalyzes the decomposition of H2O2 to produce a strong oxidizing substance ·OH. ·OH oxidizes and decomposes organic pollutants in water, achieving a degradation effect.

[0004] With the increasing complexity of industrial wastewater, the following problems arise when Fenton oxidation technology is used alone: ​​1) Low COD degradation efficiency, long oxidation reaction time, and failure to achieve the expected results; 2) Complex types of wastewater pollutants and excessively high COD concentrations require the addition of large amounts of reagents, which increases operating costs and the amount of iron sludge produced; 3) Fenton technology requires a low pH environment to degrade pollutants, and strict acid-base control is required before and after the reaction.

[0005] Currently, microwave coupling technology has become a research hotspot due to its significant effects and lack of secondary pollution. Patent CN202030607U discloses a wastewater treatment tank, including a tank body with a cavity and a top cover. A microwave transducer is installed inside the cavity, and a through hole is provided on the top cover. A conduit is inserted through the through hole for adding chemicals such as ferrous sulfate and hydrogen peroxide into the tank. By treating the same wastewater simultaneously through two methods, the wastewater treatment efficiency is improved and the wastewater treatment cost is reduced.

[0006] Although the above scheme discloses the use of microwave radiation and Fenton oxidation technology to treat wastewater simultaneously, the device is relatively simple and does not take into account that H2O2 will be consumed prematurely when directly mixed with wastewater; continuous microwave radiation will cause the temperature to rise continuously, which will accelerate the Fenton side reaction and cause H2O2 to decompose into O2 and H2O, which is not conducive to the formation of ·OH. Utility Model Content

[0007] To address the aforementioned problems, this invention provides a microwave-coupled Fenton catalytic oxidation system for treating recalcitrant organic wastewater. A circulation pipe is installed on one side of the reactor tank, connected to a hydrogen peroxide pipe via a pipe mixer. By mixing the treated wastewater with hydrogen peroxide, the hydrogen peroxide is diluted before entering the reactor tank, preventing it from being directly consumed by the high-concentration wastewater. Temperature sensors are installed on both sides of the microwave generator, connecting both to a PLC controller. The PLC controller compares the temperature from the temperature sensors with the set temperature and controls the microwave generator to reduce its irradiation power or stop irradiation altogether, preventing excessively high temperatures from accelerating the Fenton side reaction.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A microwave-coupled Fenton catalytic oxidation system for treating recalcitrant organic wastewater includes a reactor tank. An inlet pipe is installed at the bottom of one side of the reactor tank, and an outlet pipe is installed at the top. A circulation pipe is installed on the other side, and the circulation pipe is connected to a hydrogen peroxide storage tank through a hydrogen peroxide pipe. A ferrous pipe is installed above the inlet pipe, and the ferrous pipe is connected to a ferrous storage tank.

[0010] A microwave generator is installed on the top of the reactor tank, and the microwave generator is connected to a microwave transmitting antenna, which is covered by a PP sleeve. A pH meter and a temperature sensor are installed on the top of the reactor tank on both sides of the microwave generator.

[0011] Preferably, the reactor tank is divided into a reagent mixing zone, an oxidation reaction zone, and an overflow zone from bottom to top; the microwave transmitting antenna extends from the top of the reactor tank to the oxidation reaction zone, and the openings on the microwave transmitting antenna are sparse at the top and dense at the bottom.

[0012] Preferably, a ferrous metering pump is installed on the ferrous pipe, and valves are installed on both sides of the ferrous metering pump.

[0013] Preferably, the outlet pipe is connected to the sedimentation tank; the inlet pipe is connected to the acidification tank; an inlet metering pump is installed on the inlet pipe, and valves are installed on both sides of the inlet metering layer.

[0014] Preferably, a circulation pipe outlet is provided at the bottom of the reactor tank on the opposite side of the water inlet pipe, and a circulation pipe inlet is provided at the top, with the circulation pipe positioned between the circulation pipe outlet and the circulation pipe inlet.

[0015] Preferably, a pipe mixer, a first flow meter, and a circulating metering pump are installed on the circulation pipe, wherein the pipe mixer is located between the first flow meter and the outlet of the circulation pipe, and the circulating metering pump is located between the pipe mixer and the outlet of the circulation pipe; valves are installed on both sides of the circulating metering pump and between the first flow meter and the inlet of the circulation pipe.

[0016] Preferably, the pipe mixer is a three-way mixer, and the pipe mixer is connected to a hydrogen peroxide pipe.

[0017] Preferably, a hydrogen peroxide metering pump is installed on the hydrogen peroxide pipe, valves are installed on both sides of the hydrogen peroxide metering pump, and a second flow meter is installed between the hydrogen peroxide metering pump and the pipeline mixer.

[0018] Preferably, the system also includes a PLC controller, wherein the hydrogen peroxide metering pump, circulating metering pump, inlet water metering pump, ferrous iron metering pump, valves, first flow meter, second flow meter, temperature sensor, pH meter, and microwave generator are all connected to the PLC controller.

[0019] Preferably, an overflow weir is also provided inside the reactor tank at the height of the outlet pipe.

[0020] Compared with the prior art, the advantages and positive effects of this utility model are:

[0021] This invention involves installing a microwave generator on the top of the reactor tank. The microwave generator is connected to a microwave transmitting antenna to radiate microwaves into the oxidation reaction zone inside the tank. This microwave radiation accelerates the oxidation of Fe... 2+ with Fe 3+ The cycle between reactions broadens the pH range of the reaction conditions, reduces the amount of reagents used to adjust the pH range before and after the reaction, and can also promote the generation of ·OH. Through ·OH, organic pollutants in water can be non-selectively oxidized and degraded, thus removing most pollutants from the water.

[0022] This invention features a circulation pipe on one side of the reactor tank. The circulation pipe is connected to a hydrogen peroxide pipe via a pipe mixer. By mixing the treated wastewater with hydrogen peroxide, the hydrogen peroxide is diluted in one step before entering the reactor tank. This avoids the hydrogen peroxide from directly entering the reactor tank and being consumed prematurely after mixing with the high-concentration wastewater.

[0023] This invention, by installing a pH meter and a temperature sensor on both sides of a microwave generator, enables the temperature sensor to... 、 The pH meter and microwave generator are both connected to a PLC controller. The PLC controller compares the temperature from the temperature sensor with the set temperature and controls the microwave generator to reduce the irradiation power or stop irradiation to prevent the temperature from being too high and accelerating the Fenton side reaction. Attached Figure Description

[0024] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0025] Figure 1 This is a schematic diagram of the reactor structure according to an embodiment of the present invention;

[0026] In the picture:

[0027] 1. Reactor tank; 2. Inlet pipe; 201. Inlet metering pump; 3. Outlet pipe; 4. Circulation pipe; 401. Circulation metering pump; 5. Microwave generator; 6. Microwave transmitting antenna; 7. pH meter; 8. Temperature sensor; 9. Hydrogen peroxide storage tank; 10. Ferrous iron pipe; 1001. Ferrous iron metering pump; 11. Pipeline mixer; 12. Hydrogen peroxide pipe; 1201. Hydrogen peroxide metering pump; 13. First flow meter; 14. Valve; 15. Overflow weir; 16. Ferrous iron storage tank; 17. Second flow meter. Detailed Implementation

[0028] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0029] The present invention will now be described in detail with reference to the accompanying drawings. This embodiment discloses a microwave-coupled Fenton catalytic oxidation system for treating recalcitrant organic wastewater, comprising an acid-adjusting tank, a reactor tank 1, and a sedimentation tank connected in series. Wastewater first enters the acid-adjusting tank for pH adjustment. In the acid-adjusting tank, the pH range of the wastewater needs to be adjusted to 2-4.5. The wastewater with the adjusted pH range enters the reactor tank 1. After treatment in the reactor tank 1, the treated wastewater enters the sedimentation tank for further pH adjustment, and ferric hydroxide polymers are precipitated out under the action of flocculants.

[0030] Specifically, such as Figure 1 As shown, an inlet pipe 2 is installed on one side of the bottom of reactor tank 1, with the other end of the inlet pipe 2 connected to an acidification tank. An outlet pipe 3 is installed on the upper part of reactor tank 1 on the same side, with the other end of the outlet pipe 3 connected to a sedimentation tank. The interior of reactor tank 1 is divided into a reagent mixing zone, an oxidation reaction zone, and an overflow zone from bottom to top. It can be understood that wastewater enters from the bottom and exits from the top. Wastewater enters the bottom of reactor tank 1 from the acidification tank through the inlet pipe 2, passes through the reagent mixing zone, oxidation reaction zone, and overflow zone in sequence, and flows out of the reactor through the outlet pipe 3 into the sedimentation tank. In this embodiment, reactor tank 1 is made of 316 stainless steel, which is corrosion-resistant and high-temperature resistant.

[0031] like Figure 1 As shown, an inlet metering pump 201 and a valve 14 are installed on the inlet pipe 2. Valves 14 are installed on both sides of the inlet metering pump 201. The inlet metering pump 201 is used to send the sewage in the acidification tank into the reactor tank 1. The inlet metering pump 201 is connected to a PLC controller, which controls the start and stop and flow regulation of the inlet metering pump 201.

[0032] like Figure 1 As shown, a ferrous sulfate pipe 10 is installed above the inlet pipe 2, with the other end of the ferrous sulfate pipe 10 connected to a ferrous sulfate storage tank 16, which stores ferrous sulfate. A ferrous sulfate metering pump 1001 and valves 14 are installed on the ferrous sulfate pipe 10, with valves 14 on both sides of the pump. The ferrous sulfate metering pump 1001 is used to draw ferrous sulfate from the ferrous sulfate storage tank 16 and deliver it through the ferrous sulfate pipe 10 to the reagent mixing zone within the reactor tank 1. It is understood that the ferrous sulfate metering pump 1001 is connected to a PLC controller, which controls the start / stop and flow rate adjustment of the ferrous sulfate metering pump 1001.

[0033] like Figure 1 As shown, a circulation pipe outlet is located at the bottom of the reactor tank 1 opposite to the inlet pipe 2, and a circulation pipe inlet is located at the top. A circulation pipe 4 is installed between the circulation pipe outlet and the circulation pipe inlet. A pipe mixer 11, a first flow meter 13, a circulation metering pump 401, and valves 14 are installed on the circulation pipe 4. The pipe mixer 11 is located between the first flow meter 13 and the circulation pipe outlet, and the circulation metering pump 401 is located between the pipe mixer 11 and the circulation pipe outlet. Valves 14 are installed on both sides of the circulation metering pump 401, and a valve 14 is also installed between the first flow meter 13 and the circulation pipe inlet. The function of the circulation pump is to send a portion of the treated wastewater from the upper part of the reactor tank 1 back into the reactor tank 1 through the circulation pipe 4, the pipe mixer 11, and the circulation pipe outlet. The first flow meter 13 is used to monitor the flow rate of the treated wastewater flowing through the circulation pipe 4.

[0034] In this embodiment, the pipeline mixer 11 is a three-way mixer, and a hydrogen peroxide pipe 12 is connected to the pipeline mixer 11. The other end of the hydrogen peroxide pipe 12 is connected to a hydrogen peroxide storage tank 9, which stores hydrogen peroxide. A hydrogen peroxide metering pump 1201 is installed on the hydrogen peroxide pipe 12, and valves 14 are installed on both sides of the hydrogen peroxide metering pump 1201. A second flow meter 17 is installed between the hydrogen peroxide metering pump 1201 and the pipeline mixer 11. It can be understood that the hydrogen peroxide metering pump 1201, the circulating metering pump 401, the first flow meter 13, and the second flow meter 17 are all connected to a PLC controller. The first flow meter or the second flow meter is used to transmit the flow rate of the fluid passing through to the PLC controller, which can control the start and stop of the hydrogen peroxide metering pump 1201 and the circulating metering pump 401 and regulate the flow rate.

[0035] In this embodiment, hydrogen peroxide enters the pipe mixer 11 via hydrogen peroxide pipe 12, where it mixes with the treated wastewater in the upper part of the reactor tank 1. Then, the mixture is sent into the reactor tank 1 through the circulation pipe outlet, where it further mixes with the wastewater and flows upwards, coming into contact with and mixing with the ferrous sulfate transported by the ferrous sulfate pipe 10. Finally, the mixture flows upwards into the oxidation reaction zone. The H2O2 is mixed evenly in the pipe mixer and diluted before entering the reactor tank 1 to prevent premature consumption due to mixing with the high concentration of wastewater upon entering the reactor tank 1.

[0036] like Figure 1 As shown, at the height of the outlet pipe 3, an overflow weir 15 is also provided inside the reactor tank 1. The function of the overflow weir 15 is to allow the treated sewage to flow into the overflow area and be evenly discharged into the outlet pipe 3.

[0037] like Figure 1 As shown, a microwave generator 5 is installed on the top of the reactor tank. The microwave generator 5 is connected to a microwave transmitting antenna 6, which is externally protected by a waterproof device. The microwaves generated by the microwave generator 5 are transmitted to the microwave transmitting antenna 6 via a waveguide. The microwave transmitting antenna 6 is externally protected by a PP sleeve, which ensures that the microwaves radiate into the water while preventing water from seeping in and damaging the microwave generator 5. It is understandable that the number of microwave generators 5 needs to be determined based on the amount of wastewater entering the reactor tank and the difficulty of wastewater degradation. The length of the microwave transmitting antenna 6 extends from the top of the reactor tank to the oxidation reaction zone. The openings on the microwave transmitting antenna are sparse at the top and dense at the bottom to ensure that the microwaves are mainly emitted into the oxidation reaction zone, maximizing the microwave energy's effectiveness.

[0038] In this embodiment, microwave radiation can be used to accelerate the Fe... 2+ with Fe 3+ The cycle between these elements compensates for the strict pH limitations of traditional Fenton technology (pH range of 2–3.5), broadens the pH range of reaction conditions, makes the reaction conditions more relaxed, and reduces the amount of reagents needed to adjust the pH range before and after the reaction. Microwave radiation accelerates the Fe... 2+ with Fe 3+ The circulation between them results in most of the iron ions in the reactor being Fe. 2+ This can prevent the formation of ferric hydroxide precipitate in the reactor, which would affect the reaction effect.

[0039] Under microwave irradiation, the local overheating generated by microwave radiation enhances the catalytic effect of H2O2, which promotes the generation of ·OH. Through the non-selective oxidation and degradation of organic pollutants in water by ·OH, most pollutants in water can be removed.

[0040] like Figure 1As shown, a pH meter 7 and a temperature sensor 8 are also installed on the top of the reactor tank on both sides of the microwave generator 5 to monitor the reaction environment inside the reactor tank in real time. Temperature sensor 8 、 pH meter 7 and microwave generator 5 are both connected to the PLC controller.

[0041] In this embodiment, the temperature sensor 8 is linked to the microwave generator 5. Specifically, a maximum temperature is set inside the reactor tank. When the PLC controller receives a reading from the temperature sensor 8 indicating that the current temperature has reached the set maximum temperature, the PLC controller controls the microwave generator 5 to reduce the irradiation power or stop irradiation. This is because an increase in temperature inside the reactor tank accelerates the generation rate of ·OH, which facilitates the reaction of ·OH with organic pollutants and improves degradation efficiency. However, excessively high temperatures accelerate the Fenton side reaction, causing H2O2 to decompose into O2 and H2O, which is detrimental to the generation of ·OH. It should be noted that the maximum temperature is not unique and needs to be determined based on the type of wastewater.

[0042] In this embodiment, the dosage of Fenton's reagent is based on COD:H2O2:Fe 2+ The ratio is 1:(2~10):(2~10); the temperature is set to room temperature~90℃; the irradiation power of microwave generator 5 is 1kW~9kW. Before wastewater treatment, the COD:H2O2:Fe ratio is set in the PLC controller according to the type of wastewater to be treated. 2+ The PLC controller, based on a pre-set ratio, controls the flow rates of ferrous iron metering pump 1001, hydrogen peroxide metering pump 1201, and influent metering pump 201 to ensure that the ratio of ferrous iron, hydrogen peroxide, and wastewater meets the set COD:H2O2:Fe ratio. 2+ The proportion.

[0043] The concentration of hydrogen peroxide is preset in the PLC controller. The PLC controller then determines the concentration based on the preset concentration and the set COD:H2O2:Fe content. 2+ The proportion of the flow rate is controlled by the circulating metering pump 401, which adjusts the flow rate based on data from the first flow meter 13 and the second flow meter 17. The diluted hydrogen peroxide, mixed with high-concentration wastewater, reduces the concentration of wastewater entering the reactor tank, appropriately decreases the reactor pressure, and improves the degradation effect.

[0044] In this embodiment, valve 14 is an electromagnetic valve, and all valves 14 are connected to a PLC controller. The PLC controller can control the opening and closing of valve 14, thereby controlling the opening or closing of each pipeline.

[0045] The wastewater treatment system of this embodiment is used to treat chemical wastewater, which is highly toxic and difficult to degrade. The main pollutant is aniline, and the volume is 40m³. 3 / d, COD 30000mg / L, pH 4.5. Treatment setup: control group.

[0046] When using the wastewater treatment system of this embodiment, the wastewater is directly fed into reactor tank 1 without pH adjustment. The dosage of Fenton's reagent is based on the COD:H2O2:Fe ratio. 2+ The ratio of reactants was 1:2:2, microwave power was 2KW, maximum temperature was set at 45℃, and residence time was 30min. The COD of the effluent was 13500mg / L, and the COD removal rate was 55%.

[0047] The comparative example uses a standard Fenton oxidation device to treat the chemical wastewater. First, the pH of the wastewater is adjusted to 3.5. The dosage of Fenton reagent is based on the COD:H2O2:Fe... 2+ The ratio of reactants to water was 1:2:2, the residence time was 1 hour, the COD of the effluent was 19300 mg / L, and the COD removal rate was 36%.

[0048] As can be seen from the above comparative examples, with the same amount of Fenton reagent added, compared with the single Fenton oxidation process, the wastewater treatment system of this embodiment can achieve a higher COD removal rate for wastewater treatment, and has a wider range of pH control for the reaction and a faster reaction rate.

[0049] This invention couples microwave irradiation with the Fenton reaction. The thermal effect of microwave irradiation raises water temperature, intensifies Brownian motion, and increases the probability of molecular collisions, thereby accelerating the oxidation and degradation rate of organic pollutants and shortening the reaction time. Simultaneously, the non-thermal effect of microwave irradiation promotes the generation of a large amount of ·OH from H₂O₂ during the Fenton reaction. This abundant ·OH performs non-selective oxidation of wastewater, improving the degradation rate and efficiency of organic matter in the process. Compared to traditional Fenton oxidation technology using Fe... 2+ Compared to the production of ·OH by catalyst decomposition, this can reduce Fe 2+ The dosage can be adjusted to reduce operating costs and decrease the amount of iron sludge produced. Microwave irradiation can accelerate the Fe... 2+ with Fe 3+ The system utilizes a cycle between these components to overcome the stringent pH limitations of Fenton technology, broadening the reaction pH range and allowing for more relaxed reaction conditions. This reduces the amount of acid and alkali added before and after the reaction, thus lowering operating costs. Microwave radiation and the Fenton oxidation reaction occur within the same device, simplifying installation and commissioning, and requiring minimal floor space. The flow rates of the ferrous oxide metering pump, hydrogen peroxide metering pump, inlet water metering pump, and circulating metering pump are controlled by a PLC controller, resulting in a high degree of automation.

[0050] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present utility model. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solution of the present utility model are still within the scope of protection of the present utility model.

Claims

1. A microwave-coupled Fenton catalytic oxidation system for treating recalcitrant organic wastewater, characterized in that, The reactor includes a reactor tank, with an inlet pipe at the bottom of one side and an outlet pipe at the top; a circulation pipe is installed on the other side, which is connected to a hydrogen peroxide storage tank via a hydrogen peroxide pipe; and a ferrous pipe is installed above the inlet pipe, which is connected to a ferrous storage tank. A microwave generator is installed on the top of the reactor tank, and the microwave generator is connected to a microwave transmitting antenna, which is covered by a PP sleeve. A pH meter and a temperature sensor are installed on the top of the reactor tank on both sides of the microwave generator.

2. The microwave-coupled Fenton catalytic oxidation system for treating recalcitrant organic wastewater as described in claim 1, characterized in that, The reactor tank is divided into a reagent mixing zone, an oxidation reaction zone, and an overflow zone from bottom to top. The microwave transmitting antenna extends from the top of the reactor tank to the oxidation reaction zone, and the openings on the microwave transmitting antenna are sparse at the top and dense at the bottom.

3. The microwave-coupled Fenton catalytic oxidation system for treating recalcitrant organic wastewater as described in claim 1, characterized in that, A ferrous metering pump is installed on the ferrous pipe, and valves are installed on both sides of the ferrous metering pump.

4. The microwave-coupled Fenton catalytic oxidation system for treating recalcitrant organic wastewater as described in claim 1, characterized in that, The outlet pipe is connected to the sedimentation tank; the inlet pipe is connected to the acidification tank; an inlet metering pump is installed on the inlet pipe, and valves are installed on both sides of the inlet metering layer.

5. The microwave-coupled Fenton catalytic oxidation system for treating recalcitrant organic wastewater as described in claim 1, characterized in that, A circulation pipe outlet is provided at the bottom of the reactor tank on the opposite side of the water inlet pipe, and a circulation pipe inlet is provided at the top. The circulation pipe is located between the circulation pipe outlet and the circulation pipe inlet.

6. The microwave-coupled Fenton catalytic oxidation system for treating recalcitrant organic wastewater as described in claim 5, characterized in that, A pipe mixer, a first flow meter, and a circulating metering pump are installed on the circulation pipe. The pipe mixer is located between the first flow meter and the outlet of the circulation pipe, and the circulating metering pump is located between the pipe mixer and the outlet of the circulation pipe. Valves are installed on both sides of the circulating metering pump and between the first flow meter and the inlet of the circulation pipe.

7. The microwave-coupled Fenton catalytic oxidation system for treating recalcitrant organic wastewater as described in claim 6, characterized in that, The pipeline mixer is a three-way mixer, and the pipeline mixer is connected to a hydrogen peroxide pipe.

8. The microwave-coupled Fenton catalytic oxidation system for treating recalcitrant organic wastewater as described in claim 6, characterized in that, A hydrogen peroxide metering pump is installed on the hydrogen peroxide pipe, valves are installed on both sides of the hydrogen peroxide metering pump, and a second flow meter is installed between the hydrogen peroxide metering pump and the pipeline mixer.

9. The microwave-coupled Fenton catalytic oxidation system for treating recalcitrant organic wastewater as described in claim 8, characterized in that, It also includes a PLC controller, and the hydrogen peroxide metering pump, circulating metering pump, inlet water metering pump, ferrous iron metering pump, valves, first flow meter, second flow meter, temperature sensor, pH meter, and microwave generator are all connected to the PLC controller.

10. A microwave-coupled Fenton catalytic oxidation system for treating recalcitrant organic wastewater, characterized in that, An overflow weir is also installed inside the reactor tank at the height of the outlet pipe.

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