Electrocatalytic membrane filtration-microbial fuel cell coupling system and application thereof

Abstract

The application provides an electro-catalytic membrane filtration-microbial fuel cell coupling system and application thereof, and belongs to the field of wastewater treatment. The wastewater is from oil and gas field wastewater, including but not limited to fracturing flowback fluid and produced fluid. The application couples electro-catalytic oxidation technology, membrane filtration technology and microbial fuel cell technology, and applies modified activated carbon with the characteristics of electro-catalytic oxidation and reduction to form hydrogen peroxide in the electro-catalytic membrane filtration and microbial fuel cell, so that the double degradation effect of pollutants in the oil and gas field wastewater and the effect of high-efficiency removal of calcium and magnesium hardness are achieved, and the high-efficiency and low-energy-consumption reuse treatment of the oil and gas field wastewater is completed.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment and relates to an electrocatalytic membrane filtration-microbial fuel cell coupling system and its application in treating and removing pollutants from wastewater. Background Technology

[0002] Fracturing flowback fluid refers to the liquid returned from the wellbore during large-scale volumetric fracturing. It contains unbroken fracturing fluid, breaker agents, various fracturing additives, and impurities such as rock and sediment. Directly discharging untreated or poorly treated flowback fluid into the environment can cause severe damage. Flowback fluid recycling is one of the effective methods for treating oil and gas field wastewater, and developing efficient oil and gas field wastewater reuse technologies has far-reaching significance.

[0003] Membrane treatment technology is a very promising field in wastewater treatment. However, current limitations of traditional membrane treatment for high-salinity organic wastewater include membrane fouling and poor treatment efficiency. Electroadsorption desalination can remove salt without a separation membrane and has proven to exhibit superior desalination performance compared to traditional electrodialysis and reverse osmosis. Electrocatalytic membrane filtration is a widely accepted technology for removing salt and partially degrading organic pollutants. Microbial fuel cells (MFCs) can utilize the metabolism of microorganisms to convert the chemical energy in organic matter into electrical energy. When the two are coupled, electrocatalytic membrane filtration can retain suspended solids in wastewater, effectively remove salt, and the intermediate products or incompletely degraded organic matter generated during the process can be further utilized and converted into substrates for microorganisms in the MFC, thereby improving the overall organic pollutant removal efficiency of the system. Simultaneously, the electrical energy generated by the MFC can provide energy support for electrocatalytic membrane filtration, thereby reducing external energy demand and achieving effective energy recovery and utilization. Therefore, realizing the coupled treatment of oil and gas field wastewater using electrocatalytic membrane filtration and MFC is a promising area of ​​research.

[0004] This invention also applies modified activated carbon with electrocatalytic oxygen reduction to form hydrogen peroxide to electrocatalytic membrane filtration and microbial fuel cells, achieving a dual degradation effect on pollutants in oil and gas field wastewater and realizing the treatment of oil and gas field wastewater. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention aims to provide an electrocatalytic membrane filtration-microbial fuel cell coupling system and its application. The coupling system provided by this invention combines electrocatalytic oxidation technology, membrane filtration technology, capacitive deionization technology, electrodeposition oxidation technology, and microbial fuel cell technology, fully leveraging the advantages of these five technologies while avoiding their disadvantages, achieving high-efficiency, low-energy-consumption reuse treatment of oil and gas field wastewater.

[0006] This invention is achieved through the following technical solution:

[0007] This invention provides an electrocatalytic membrane filtration-microbial fuel cell coupling system, comprising a pretreatment module, an electrocatalytic membrane filtration module, and a microbial fuel cell module; the pretreatment module, the electrocatalytic membrane filtration module, and the microbial fuel cell module are connected in series, the electrocatalytic membrane filtration module is connected to a DC power supply, and the microbial fuel cell module includes a microbial fuel cell and an aeration system, wherein the aeration system aerates the cathode of the microbial fuel cell through an air pump, and the electricity generated by the microbial fuel cell module is recycled to the electrocatalytic membrane filtration module.

[0008] Furthermore, the pretreatment module is used for simple filtration of large particles, silt, floating oil, and other impurities in the water.

[0009] Furthermore, the cathode of the electrocatalytic membrane filtration module includes an insulating frame, a conductive filter membrane, a conductive coating, and a water pump. The insulating frame and the conductive filter membrane form a flat box-shaped body. The two sides of the box-shaped body with the largest area are the conductive filter membrane. The conductive filter membrane is supported and connected around the insulating frame. The box-shaped body has a water outlet, which is connected to the water pump through a pipe. The conductive coating is set on the two outer sides of the box-shaped body and is a container with micropores on its surface. The container contains filler with electrocatalytic and adsorption properties.

[0010] Furthermore, the insulating frame for the reserved water outlet is made of plastic, preferably a rectangular or cylindrical acrylic plate frame.

[0011] Furthermore, the conductive filter membrane is a low-cost conductive carbon material with excellent conductivity, such as carbon fiber cloth, carbon fiber cloth coated with polyvinylidene fluoride (PVDF), or carbon felt.

[0012] Furthermore, the conductive coating is detachable and can be movably and tightly installed on the outside of the insulating frame;

[0013] Furthermore, the filler in the conductive coating is cobalt- and cerium-loaded activated carbon particles (CoCe / AC) or other conductive granular adsorbent materials with electrocatalytic oxidation-reduction properties.

[0014] Furthermore, the electrocatalytic membrane filtration module is particularly suitable for removing calcium and magnesium hardness.

[0015] Furthermore, the microbial fuel cell is a dual-chamber air-cathode microbial fuel cell; the upper part is the anode chamber, and water enters from the bottom of the anode chamber, while the upper part is the cathode chamber;

[0016] Furthermore, the anode chamber of the microbial fuel cell is filled with a layer of activated carbon particles loaded mainly with Shewanella bacteria.

[0017] Furthermore, the cathode chamber of the microbial fuel cell is filled with activated carbon particles (CoCe / AC) loaded with cobalt and cerium to catalytically reduce organic pollutants to produce hydrogen peroxide, thereby achieving further degradation of organic matter.

[0018] Furthermore, in this invention, the electrocatalytic membrane filtration module and the microbial fuel cell module use the same type of cobalt- and cerium-loaded activated carbon particles (CoCe / AC).

[0019] Further, the CoCe / AC preparation process is as follows: a certain amount of Co(NO3)2 and Ce(NO3)2 are added to an appropriate amount of deionized water, followed by the addition of a nitrogen source and stirring to obtain a homogeneous solution. The mass fraction of the nitrogen source in the homogeneous solution is 2-3 wt%. An appropriate amount of water-washed activated carbon is mixed by an equal-volume soaking method and ultrasonically treated, followed by drying overnight in a forced-air drying oven at 75-85℃. The resulting dried particles are then further sintered at high temperature in a muffle furnace.

[0020] Furthermore, the mass ratio of cobalt to cerium used in the CoCe / AC is 0.15:1 to 0.3:1; the soaking method for mixing and ultrasonic treatment takes 30 to 60 minutes.

[0021] Furthermore, urea or melamine is used as a nitrogen source in the CoCe / AC preparation process;

[0022] Furthermore, the high-temperature sintering temperature is 400–550°C, and the time is 2–3 hours.

[0023] This invention also provides an application of the electrocatalytic membrane filtration-microbial fuel cell coupling system described in the above technical solution, applied to the treatment of oil and gas field wastewater, specifically as follows: Wastewater enters the pretreatment module for the removal of large particulate waste; then it enters the electrocatalytic membrane filtration module, where a water pump extracts water from the box-shaped body of the insulating frame, creating a negative pressure within the box-shaped body of the insulating frame, causing the wastewater to flow through the conductive coating and conductive filter membrane. On the one hand, it can effectively remove calcium and magnesium ions from the oil and gas field wastewater using electrostatic precipitation and capacitive deionization technologies; on the other hand, it can remove suspended matter and disrupt the structure and reduce the toxicity of large molecular organic matter in the oil and gas field wastewater through physical interception, electroadsorption, and electrocatalysis technologies; finally, it enters the microbial fuel cell module to treat the primary wastewater treated by the electrocatalytic membrane filtration module. The MFC can effectively remove COD from the wastewater to meet treatment standards.

[0024] The voltage of the DC power supply is 0.5–1.0V;

[0025] The area of ​​the conductive filter membrane is 0.1–0.3 m³.

[0026] The thickness of the conductive coating is 1.5–2.5 cm.

[0027] The wastewater flux of the electrocatalytic membrane filtration module is 200–300 L·m³. - 3·h -1

[0028] The beneficial effects of this invention are as follows: The electrocatalytic membrane filtration module in the coupling system provided by this invention can improve the biodegradability of oil and gas field wastewater and achieve effective desalination and decontamination functions. Specifically, it can effectively remove calcium and magnesium ions from oil and gas field wastewater using electrostatic precipitation and capacitive deionization technologies. Furthermore, it removes suspended solids and disrupts the structure and reduces the toxicity of macromolecular organic matter through physical interception, electroadsorption, and electrocatalysis. The microbial fuel cell module (MFC) in the coupling system provided by this invention treats the primary wastewater after treatment by the electrocatalytic membrane filtration module. The MFC can effectively remove COD from the wastewater to meet treatment standards. In addition, the electricity generated by the MFC from organic matter can provide energy support for the electrocatalytic membrane filtration. This invention provides an electrocatalytic membrane filtration-microbial fuel cell coupling system and its application, which can effectively remove calcium and magnesium ions, suspended solids, and COD from oil and gas field wastewater. The data from the examples show that the present invention can achieve the standard treatment of calcium and magnesium in fracturing flowback fluid and a COD removal rate of 88.8%; and achieve the effective treatment of calcium and magnesium in produced fluid and a COD removal rate of 56.35%. Attached Figure Description

[0029] Figure 1 This is a flowchart of an electrocatalytic membrane filtration-microbial fuel cell coupling system according to the present invention;

[0030] Figure 2 This is a schematic diagram of an electrocatalytic membrane filtration-microbial fuel cell coupling system according to the present invention;

[0031] Figure 3 This is a schematic diagram of the electrocatalytic membrane filtration module of the coupled system;

[0032] Figure 4 This is a schematic diagram of a microbial fuel cell module in a coupled system. Detailed Implementation

[0033] This invention provides an electrocatalytic membrane filtration-microbial fuel cell coupling system, comprising a pretreatment module, an electrocatalytic membrane filtration module, and a microbial fuel cell module; the pretreatment module, the electrocatalytic membrane filtration module, and the microbial fuel cell module are connected in series, the electrocatalytic membrane filtration module is connected to a DC power supply, and the microbial fuel cell module includes a microbial fuel cell and an aeration system, wherein the aeration system aerates the cathode of the microbial fuel cell through an air pump.

[0034] The coupling system described in this invention comprises a water circuit consisting of a pretreatment module, an electrocatalytic membrane filtration module, and a microbial fuel cell module connected in sequence. The water circuit of the electrocatalytic membrane filtration-microbial fuel cell coupling system is described in detail below:

[0035] The water circuit of the coupling system described in this invention includes a pretreatment module. The purpose of the pretreatment module is to remove solid particles, suspended colloids, and floating oil layers from oil and gas field wastewater. This invention does not limit the specific device of the pretreatment module, as long as it can remove solid particles, suspended colloids, and floating oil layers from the oil and gas field wastewater; specifically, it can be a filter cloth or a screen.

[0036] The water circuit of the coupling system described in this invention includes an electrocatalytic membrane filtration module. Figure 3 This is a schematic diagram of the electrocatalytic membrane filtration module of the coupling system. The cathode of the electrocatalytic membrane filtration module consists of a plastic frame with a reserved water outlet, a conductive filter membrane installed on the plastic frame, a movable conductive coating covering the conductive filter membrane, and a pipeline connecting the water outlet and the water pump.

[0037] The plastic frame for the reserved water outlet is preferably a rectangular acrylic plate frame;

[0038] The conductive filter membrane is preferably a carbon fiber cloth coated with PVDF;

[0039] The movable conductive coating consists of a preferred rectangular container that can be movably mounted on the outside of a plastic frame and a filler with adsorption properties.

[0040] The filler material of the movable conductive layer is activated carbon particles loaded with cobalt and cerium (CoCe / AC);

[0041] The electrocatalytic membrane filtration module in the coupling system provided by this invention can improve the biodegradability of oil and gas field wastewater and achieve effective desalination and decontamination. Its principle is as follows: a stable DC electric field is formed by applying a DC power supply to the electrocatalytic membrane filtration module immersed in wastewater. Under the action of the DC electric field, cations migrate towards the negatively charged filtration membrane. The movable conductive adsorbent layer, which is in close contact with the conductive filtration membrane and is negatively charged, can physically trap and electro-adsorb colloidal or suspended substances in the oil and gas field wastewater. These substances are catalytically degraded by the electrocatalytically active filler in the movable conductive adsorbent layer, producing carbon dioxide. This facilitates the precipitation of calcium and magnesium salt ions on the surface of the electrocatalytic membrane filtration module, contributing to the hardness of calcium and magnesium. The cations that migrate to the cathode are adsorbed by the trapped colloidal substances or catalytic degradation intermediates, and are removed by precipitation under the action of the electrode electric field and membrane surface polarization. The electrocatalytic membrane filtration module in the coupling system provided by this invention can effectively remove calcium and magnesium ions from oil and gas field wastewater using electrostatic precipitation and capacitive deionization technologies. On the other hand, it removes suspended matter and breaks down the structure and reduces the toxicity of macromolecular organic matter in oil and gas field wastewater through physical interception, electroadsorption, and electrocatalysis technologies. This increases the biodegradability of the water sample treated by the electrocatalytic membrane filtration module, making it more suitable for subsequent treatment by microbial fuel cells.

[0042] The water circuit of the coupling system of the present invention includes a microbial fuel cell module, which includes a microbial fuel cell and an aeration system. The aeration system aerates the cathode of the microbial fuel cell through an air pump. Figure 4 The diagram shows a microbial fuel cell module of a coupled system, wherein the microbial fuel cell is a dual-chamber air-cathode microbial fuel cell; the anode of the microbial fuel cell is a layered activated carbon particle loaded with Shewanella bacteria; the cathode of the microbial fuel cell module is CoCe / AC activated carbon particle, and an air pump is used to aerate the cathode.

[0043] In this invention, the electrocatalytic membrane filtration module and the microbial fuel cell module use the same type of cobalt- and cerium-loaded activated carbon particles (CoCe / AC).

[0044] The preferred mass ratio of cobalt to cerium used in the CoCe / AC is 0.2:1;

[0045] Urea is used as the preferred nitrogen source in the CoCe / AC preparation process described above;

[0046] The preferred preparation process for CoCe / AC is as follows: 0.596g of Co(NO3)2 and 2.92g of Ce(NO3)2 are added to 100mL of deionized water, followed by the addition of urea and stirring to obtain a homogeneous solution. The mass fraction of urea in the homogeneous solution is 2wt%. 75g of washed activated carbon is mixed by an equal-volume soaking method and ultrasonically treated for 30min, followed by drying in a 75℃ forced-air drying oven for 12h. The dried granules are then further heated to 400℃ in a muffle furnace at a heating rate of 5℃ / min and annealed for 2h to obtain the final product, named CoCe / AC.

[0047] The microbial fuel cell module in the coupling system provided by this invention requires a three-stage acclimatization process before activation. The first stage preferably uses a 1:1 mixture of oil and gas field wastewater and nutrient solution treated by an electrocatalytic membrane filtration module as the substrate for acclimatization. Once the MFC output voltage stabilizes, the next stage of acclimatization can begin. The second stage preferably uses a 2:1 mixture of oil and gas field wastewater and nutrient solution treated by an electrocatalytic membrane filtration module as the substrate for acclimatization. Once the MFC output voltage stabilizes, the next stage of acclimatization can begin. The third stage uses only oil and gas field wastewater treated by an electrocatalytic membrane filtration module as the substrate for acclimatization. Ultimately, a stable output voltage indicates that the electrogenic microorganisms have adapted to the characteristics of the actual wastewater.

[0048] The present invention also provides the application of the electrocatalytic membrane filtration-microbial fuel cell coupling system described in the above technical solution in the treatment of oil and gas field wastewater.

[0049] In this invention, the oil and gas field wastewater includes fracturing flowback fluid and produced fluid.

[0050] The following detailed description, in conjunction with embodiments, illustrates an electrocatalytic membrane filtration-microbial fuel cell coupling system and its application provided by the present invention. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0051] The following embodiments further illustrate the technical solutions and drawings of the present invention, but are not intended to limit the scope of protection of the present invention.

[0052] Example 1

[0053] The oil and gas field wastewater used in this embodiment is fracturing flowback fluid, with a calcium ion concentration of 1741.8 mg / L, a magnesium ion concentration of 73.2 mg / L, and a COD of 6250 mg / L.

[0054] The cathode of the electrocatalytic membrane filtration module consists of a rectangular acrylic plate frame (12cm x 17cm) with a pre-drained outlet, two PVDF carbon fiber cloths (10cm x 15cm) mounted on the rectangular frame, a movable conductive CoCe / AC coating tightly covering the rectangular frame, and piping connecting the outlet and the water pump. The anode is a carbon fiber cloth cathode, using a diaphragm-free two-electrode system. The applied DC voltage is 0.75V, the movable conductive coating thickness is 2.0cm, and the flux is 240 L·m⁻². - 3·h -1 The effluent calcium ion removal rate was 78.27%, magnesium ion removal rate was 40%, and COD removal rate was 43.2%. The resulting wastewater enters the microbial fuel cell module.

[0055] The microbial fuel cell (MFC) startup process in the microbial fuel cell stack module is divided into three stages. The first stage preferably uses a 1:1 mixture of the aforementioned wastewater and nutrient solution as the substrate for acclimatization. Once the MFC output voltage stabilizes, the next acclimatization stage begins, with the output voltage stabilizing at 0.1–0.2V. The second stage preferably uses a 2:1 mixture of the aforementioned wastewater and nutrient solution as the substrate for acclimatization. Once the MFC output voltage stabilizes, the next acclimatization stage begins, with the output voltage stabilizing at 0.4–0.6V. The third stage uses only the aforementioned wastewater as the substrate for acclimatization, ultimately stabilizing the output voltage at approximately 0.7V. This indicates that the electrogenic microorganisms have adapted to the characteristics of the actual wastewater and are effectively treating it. The final COD content of the effluent from the microbial fuel cell stack module is 700.5 mg / L, with a removal rate of 88.8%.

[0056] Example 2

[0057] The oil and gas field wastewater used in this embodiment is produced fluid, with a calcium ion concentration of 23128.0 mg / L, a magnesium ion concentration of 326.8 mg / L, and a COD of 1970 mg / L.

[0058] The cathode of the electrocatalytic membrane filtration module consists of a rectangular acrylic plate frame (12cm x 17cm) with a pre-drained outlet, two PVDF carbon fiber cloths (10cm x 15cm) mounted on the rectangular frame, a movable conductive CoCe / AC coating tightly covering the rectangular frame, and piping connecting the outlet and the water pump. The anode is a carbon fiber cloth cathode, using a diaphragm-free two-electrode system. The applied DC voltage is 0.5V, the movable conductive coating thickness is 2.0cm, and the flux is 300L·m. - 3·h -1The effluent calcium ion removal rate was 31.12%, magnesium ion removal rate was 18.76%, and COD removal rate was 12.45%. The resulting wastewater enters the microbial fuel cell module.

[0059] The microbial fuel cell (MFC) startup process in the microbial fuel cell stack module is divided into three stages. The first stage preferably uses a 1:1 mixture of the aforementioned wastewater and nutrient solution as the substrate for acclimatization. Once the MFC output voltage stabilizes, the next acclimatization stage begins, with the output voltage stabilizing between 0.01 and 0.05 V. The second stage preferably uses a 2:1 mixture of the aforementioned wastewater and nutrient solution as the substrate for acclimatization. Once the MFC output voltage stabilizes, the next acclimatization stage begins, with the output voltage stabilizing between 0.1 and 0.2 V. The third stage uses only the aforementioned wastewater as the substrate for acclimatization, ultimately stabilizing the output voltage at approximately 0.4 V. This indicates that the electrogenic microorganisms have adapted to the characteristics of the actual wastewater and are effectively treating it. The final COD content of the effluent from the microbial fuel cell stack module is 860.2 mg / L, with a removal rate of 56.34%.

[0060] This invention provides an electrocatalytic membrane filtration-microbial fuel cell coupling system and its application, which couples electrocatalytic oxidation technology, membrane filtration technology and microbial fuel cell technology. It also applies modified activated carbon with the property of electrocatalytic oxygen reduction to form hydrogen peroxide to the electrocatalytic membrane filtration and microbial fuel cell, achieving the dual degradation effect of pollutants in oil and gas field wastewater and the efficient removal of calcium and magnesium hardness, thus completing the high-efficiency and low-energy-consumption reuse treatment of oil and gas field wastewater.

Claims

1. An electrocatalytic membrane filtration-microbial fuel cell coupling system, characterized in that, It includes a pretreatment module, an electrocatalytic membrane filtration module, and a microbial fuel cell module; the pretreatment module, the electrocatalytic membrane filtration module, and the microbial fuel cell module are connected in series in sequence. The electrocatalytic membrane filtration module is connected to a DC power supply. The microbial fuel cell module includes a microbial fuel cell and an aeration system. The aeration system aerates the cathode of the microbial fuel cell through an air pump. The electricity generated by the microbial fuel cell module is recycled to the electrocatalytic membrane filtration module. The cathode of the electrocatalytic membrane filtration module includes an insulating frame, a conductive filter membrane, a conductive coating, and a water pump. The insulating frame and the conductive filter membrane form a flat box-shaped body. The two sides of the box-shaped body with the largest area are the conductive filter membrane. The conductive filter membrane is supported and connected around the insulating frame. The box-shaped body has a water outlet, which is connected to the water pump through a pipe. The conductive coating is set on the two outer sides of the box-shaped body and is a container with micropores on its surface. The container contains filler with electrocatalytic and adsorption properties. The microbial fuel cell is a dual-chamber air-cathode microbial fuel cell; the lower part is the anode chamber, with water entering from the bottom of the anode chamber, and the upper part is the cathode chamber; The anode chamber of the microbial fuel cell is filled with an activated carbon particle layer mainly loaded with Shewanella bacteria; the cathode chamber of the microbial fuel cell is filled with activated carbon particles loaded with cobalt and cerium to catalytically reduce organic pollutants to produce hydrogen peroxide, thereby further degrading organic matter; the electrocatalytic membrane filtration module is suitable for removing calcium and magnesium hardness; the conductive coating is detachable and can be movably and tightly installed on the outside of the insulating frame; the filler in the conductive coating is activated carbon particles loaded with cobalt and cerium.

2. The electrocatalytic membrane filtration-microbial fuel cell coupling system according to claim 1, characterized in that, The pretreatment module is used to remove large particulate impurities from wastewater.

3. The electrocatalytic membrane filtration-microbial fuel cell coupling system according to claim 1, characterized in that, The insulating frame of the reserved water outlet is made of plastic; the conductive filter membrane is carbon fiber cloth or carbon felt coated with polyvinylidene fluoride (PVDF).

4. The electrocatalytic membrane filtration-microbial fuel cell coupling system according to claim 1, characterized in that, The electrocatalytic membrane filtration module and the microbial fuel cell module use the same type of cobalt and cerium-loaded activated carbon particles. The CoCe / AC preparation process is as follows: a certain amount of Co(NO3)2 and Ce(NO3)2 are added to an appropriate amount of deionized water, followed by the addition of a nitrogen source and stirring to obtain a homogeneous solution. The mass fraction of the nitrogen source in the homogeneous solution is 2-3 wt%. An appropriate amount of water-washed activated carbon is mixed by an equal-volume soaking method and ultrasonically treated, followed by drying overnight in a forced-air drying oven at 75-85 ℃. The dried particles are then further sintered at high temperature in a muffle furnace.

5. The electrocatalytic membrane filtration-microbial fuel cell coupling system according to claim 4, characterized in that, The mass ratio of cobalt to cerium used in the CoCe / AC is 0.15:1 to 0.3:1; the soaking method mixing and ultrasonic treatment time is 30 to 60 minutes; urea or melamine is used as a nitrogen source in the CoCe / AC preparation process; the high-temperature sintering temperature is 400 to 550°C and the time is 2 to 3 hours.

6. The application of the electrocatalytic membrane filtration-microbial fuel cell coupling system according to any one of claims 1-5, characterized in that, In the treatment of oil and gas field wastewater, the specific process is as follows: Wastewater enters the pretreatment module for the removal of large particulate waste; then it enters the electrocatalytic membrane filtration module, where a water pump extracts water from the box-shaped body of the insulating frame, creating a negative pressure within the box-shaped body. This causes the wastewater to flow through a conductive coating layer and a conductive filter membrane. On the one hand, electrostatic precipitation and capacitive deionization technologies effectively remove calcium and magnesium ions from the oil and gas field wastewater; on the other hand, physical interception, electroadsorption, and electrocatalysis technologies remove suspended solids and disrupt the structure and reduce the toxicity of large organic molecules. Finally, the wastewater enters the microbial fuel cell module to treat the primary wastewater treated by the electrocatalytic membrane filtration module. The MFC effectively removes COD from the wastewater to meet treatment standards.

7. The application according to claim 6, characterized in that, The voltage of the DC power supply is 0.5~1.0 V; the area of ​​the conductive filter membrane is 0.1~0.3 m². 3 The thickness of the conductive coating is 1.5~2.5 cm; the wastewater flux of the electrocatalytic membrane filtration module is 200~300 L. . m -3. h -1 .

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