Modular microbial fuel cell type constructed wetland system

Abstract

The application discloses a modular microbial fuel cell type artificial wetland system, and relates to the technical field of water pollution control and water treatment. The modular microbial fuel cell type artificial wetland system comprises a water inlet channel, a wetland treatment area and a water outlet channel which are sequentially connected. The wetland treatment area comprises a plurality of treatment units which are arranged in parallel. The water inlet of the treatment unit is connected with the water inlet channel, and the water outlet of the treatment unit is connected with the water outlet channel. Each treatment unit comprises a plurality of microbial fuel cells which are connected in series. The two ends of the microbial fuel cell are respectively provided with a water inlet and a water outlet. The electrode lead-out ends with opposite polarities are arranged on the water inlet side and the water outlet side respectively. The water inlets and the water outlets of adjacent microbial fuel cells are detachably connected. The electrode lead-out ends with opposite polarities of adjacent microbial fuel cells are detachably connected. The application can enhance the organic matter degradation capacity and degradation rate of the wetland system by using the microbial fuel cell, and can ensure the electric energy output of the microbial fuel cell on the basis of solving the clogging problem.

Description

Technical Field

[0001] This invention relates to the field of water pollution control and water treatment technology, and in particular to a modular microbial fuel cell type constructed wetland system. Background Technology

[0002] Constructed wetlands remove pollutants from water through the synergistic effects of physical, chemical, and biological processes involving wetland plants, substrates, and microbial communities. As a low-cost, low-energy ecological wastewater treatment technology, constructed wetlands offer significant advantages in wastewater treatment and the ecological restoration of slightly polluted water bodies, and have seen rapid development and recognition in recent years, particularly in sponge city construction, black and odorous water body remediation, and rural wastewater treatment. However, constructed wetlands also face challenges such as low organic load, large land area requirements, and susceptibility to clogging during long-term operation, all of which constrain the technological development of constructed wetlands.

[0003] During long-term operation, constructed wetlands may experience blockages, short-flow, and substrate saturation, leading to a decline in their treatment capacity. Traditional solutions to these problems include backwashing or replacing the packing material and plants, but these methods are complex, costly, have long recovery periods, and exhibit poor stability. Currently, modular wetland design is a more widely researched solution. Modular designs allow for partial replacement / washing through detachable and separable components, simplifying operation, reducing costs, and minimizing damage to system stability. For example, Chinese patent application CN105858900A discloses a modular grid-type combined constructed wetland system, comprising an inlet distribution area, a wetland system treatment area, and an outlet collection area connected in sequence. The wetland system treatment area includes multiple treatment units composed of grid-type wetland troughs connected in series. Each treatment unit is connected to an outlet on the inlet distribution area, and the outlets of the treatment units are connected to the outlet collection area. Perforated water distribution baffles are installed on the outlet surfaces of both the inlet distribution area and the inlet surfaces of the outlet collection area. This approach can address localized blockages in constructed wetlands by replacing or adjusting existing structures, thus reducing the overall impact on the wetland system. However, it can only effectively solve the blockage problem; it cannot significantly improve the wetland's processing capacity or reduce its land occupation.

[0004] Introducing microbial fuel cell technology into constructed wetlands involves constructing a rationally designed battery chamber and utilizing the microbial community within the wetland to create various effects, such as the electrode-microbial electrode effect, the plant-microbial rhizosphere effect, and the matrix-microbial biofilm effect. Electrogenic microorganisms promote the degradation of pollutants, thereby enhancing the removal capacity of the constructed wetland, while simultaneously converting the organic matter energy of the pollutants into electrical energy for collection. For example, Chinese patent application CN113540542A discloses a constructed wetland microbial battery, including a downstream reactor, an anode, and an air cathode. The downstream reactor is internally separated by a glass fiber cotton partition layer, dividing the reactor's interior into an upper and lower chamber. Both the upper and lower chambers are filled with gravel and anaerobic sludge. The anode and air cathode are located at the bottom and top of the downstream reactor, respectively. The anode comprises a first stainless steel mesh and a first graphite felt, with the first graphite felt positioned outside the first stainless steel mesh. The air cathode comprises a second stainless steel mesh and a second graphite felt, with the second stainless steel mesh wrapped around the second graphite felt. The aim of this scheme is to eliminate the need for planting plants and to reduce sludge blockage by using gravel for support. However, in actual operation, blockage still occurs, and the output voltage and power remain low. Furthermore, blockage increases the internal resistance of the matrix, affecting electron / proton transfer efficiency and the energy output of electrogenic bacteria. This hinders electron / proton transmission, increases the battery's internal resistance, and ultimately reduces power generation efficiency.

[0005] Currently, research on the coupling technology of constructed wetlands and microbial fuel cells is mostly limited to how to improve the weak voltage and effectively utilize it, but it is powerless to address the clogging problem. Summary of the Invention

[0006] The purpose of this invention is to provide a modular microbial fuel cell-based constructed wetland system to solve the problems existing in the prior art. By connecting microbial fuel cells in series to form processing units, and connecting several processing units in parallel to form a wetland treatment area, the microbial fuel cells can enhance the organic matter degradation capacity and degradation rate of the wetland system. At the same time, the microbial fuel cells in the blocked locations can be replaced to ensure the power output of the microbial fuel cells while solving the blockage problem.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] This invention provides a modular microbial fuel cell-type constructed wetland system, comprising an inlet channel, a wetland treatment area, and an outlet channel connected in sequence. The wetland treatment area includes several treatment units arranged in parallel. The inlet of each treatment unit is connected to the inlet channel, and the outlet of each treatment unit is connected to the outlet channel. Each treatment unit includes several microbial fuel cells connected in series. Each microbial fuel cell has an inlet and an outlet at both ends, and electrode leads with opposite polarities are respectively provided on the inlet and outlet sides. The inlets and outlets of adjacent microbial fuel cells are detachably connected, and the electrode leads with opposite polarities of adjacent microbial fuel cells are also detachably connected.

[0009] Preferably, the microbial fuel cell is divided into type A, type B and type C modules according to the different connection parts. Type A module is provided with a first connection part at both ends, type B module is provided with a second connection part at both ends, and type C module is provided with a first connection part and a third connection part at both ends. The first connection part is connected to the second connection part, and the third connection part is connected to the inlet channel or the outlet channel.

[0010] Preferably, the first connecting part includes a card plate, a first hole distributed on the card plate, and a conductive plug disposed in the middle of the card plate. The second connecting part includes a card slot that cooperates with the card plate, a second hole distributed on the card slot, and a conductive insert disposed in the middle of the card slot. The conductive plug and the conductive insert are respectively connected to different electrodes, and the conductive plug and the conductive insert can be connected after the card plate and the card slot are plugged in.

[0011] Preferably, the card slot includes sliding grooves on both sides and a limiting groove at the bottom, and the card plate is provided with a first insertion part corresponding to the sliding groove on both sides, and a second insertion part corresponding to the limiting groove at the bottom of the card plate.

[0012] Preferably, the first insertion part is provided with a plurality of rollers arranged sequentially along the insertion direction, and one side of the slide groove is provided with a slide rail at a position corresponding to the roller.

[0013] Preferably, a rubber pad is provided on the other side of the slide groove and the other side of the limiting groove, and after the roller enters the slide, it will attach the back of the first insertion part to the rubber pad.

[0014] Preferably, the third connecting part includes a fixing ring, and guide rods are provided at the water inlet channel and the water outlet channel, and the fixing ring can be inserted into the guide rods when it moves downward.

[0015] Preferably, the third connection part includes a downward-facing socket that communicates with the interior of the microbial fuel cell. Both the water inlet channel and the water outlet channel are connected to a vertically upward-facing water pipe. The water pipe is equipped with a switch valve. The socket is inserted downward into the water pipe to achieve communication.

[0016] Preferably, the microbial fuel cell includes a packing bed and wetland plants. The packing bed includes a support layer, a middle matrix layer, and an upper matrix layer arranged from bottom to top. An anode material is laid at the bottom of the middle matrix layer, and a cathode material is laid at the top of the upper matrix layer. The cathode material and the anode material are respectively connected to different electrode leads. Wetland plants are planted in the upper matrix layer.

[0017] Preferably, the supporting layer is 20cm thick, and the substrate is gravel or crushed stone with a particle size of φ16-30mm; the middle substrate layer is 35cm thick, and the substrate is gravel or zeolite with a particle size of φ4-15mm; the upper substrate layer is 15cm thick, and the substrate is coarse sand or soil with a smaller particle size; the wetland plants are reeds, calamus, and canna lilies; the cathode material and the anode material are activated carbon layers or graphite blankets.

[0018] The present invention achieves the following technical effects compared to the prior art:

[0019] (1) The present invention uses microbial fuel cells connected in series to form a treatment unit, and several treatment units connected in parallel to form a wetland treatment area. It can use microbial fuel cells to enhance the organic matter degradation capacity and degradation rate of the wetland system. At the same time, it can replace the microbial fuel cells in the blocked position to ensure the power output of the microbial fuel cells while solving the blockage problem. Therefore, the present invention can solve the wetland blockage problem, improve the wetland treatment capacity, and convert organic matter into power output for utilization.

[0020] (2) The present invention divides the microbial fuel cell into type A module, type B module and type C module. It can make convenient connection between modules and between modules and inlet and outlet channels by utilizing the different connection parts set in each module, and conveniently remove and replace the microbial fuel cell that is blocked.

[0021] (3) The present invention utilizes the cooperation of the slot and the plate to realize the plug-in connection of adjacent microbial fuel cells. The slot includes a sliding groove on both sides and a limiting groove at the bottom. After the plate and the slot are plugged in, a semi-enclosed structure can be formed at the bottom and both sides, connecting the first hole and the second hole within the semi-enclosed structure to ensure the sealing of the connection and enable the water to flow smoothly in the series sequence of the microbial fuel cells, thus ensuring the treatment effect of the wetland system.

[0022] (4) When installing the card plate and the card slot, the present invention can use the cooperation of rollers and slides to achieve accurate, fast and labor-saving positioning for the assembly and disassembly of the card plate and the card slot. The vertical loading and unloading connection method makes it easier to remove and install the microbial fuel cell. In addition, a rubber pad is provided in the slide. After the card plate and the card slot are installed, the rollers can be used to attach the first insertion part of the card plate to the rubber pad to form a relatively closed semi-enclosed communication space, which further improves the sealing of the connection between adjacent microbial fuel cells. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a plan view of the constructed wetland system of the present invention;

[0025] Figure 2 This is a structural diagram of the microbial fuel cell of the present invention;

[0026] Figure 3 This is a schematic diagram of the A-type module structure of the present invention;

[0027] Figure 4 This is a schematic diagram of the B-type module structure of the present invention;

[0028] Figure 5 This is a schematic diagram of the C-type module structure of the present invention;

[0029] Figure 6 This is a top view of the combination of type A and type B modules of the present invention;

[0030] Figure 7 for Figure 6 The front view;

[0031] Figure 8 This is a schematic diagram showing the connection between the C-type module of the present invention and the inlet / outlet channel;

[0032] Figure 9 This is a schematic diagram showing the specific arrangement of the processing unit of the present invention;

[0033] The components include: 1. Inlet channel; 11. Guide rod; 12. Water pipe; 2. Treatment unit; 21. Type A module; 211. First connecting part; 2111. Roller; 2112. Conductive plug; 2113. First hole; 22. Type B module; 221. Second connecting part; 2211. Slide rail; 2212. Conductive socket; 2213. Second hole; 2214. Slide groove; 2215. Limiting groove; 2216. Rubber pad; 23. Type C module; 231. Third connecting part; 2311. Socket hole; 2312. Fixing ring; 3. Outlet channel; 4. Wetland treatment area; 5. Cathode material; 6. Anode material; 7. Upper matrix layer; 8. Middle matrix layer; 9. Supporting layer; 10. Wetland plants. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] The purpose of this invention is to provide a modular microbial fuel cell-based constructed wetland system to solve the problems existing in the prior art. By connecting microbial fuel cells in series to form processing units, and connecting several processing units in parallel to form a wetland treatment area, the microbial fuel cells can enhance the organic matter degradation capacity and degradation rate of the wetland system. At the same time, the microbial fuel cells in the blocked locations can be replaced to ensure the power output of the microbial fuel cells while solving the blockage problem.

[0036] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] like Figures 1-9As shown, this invention provides a modular microbial fuel cell-type constructed wetland system, comprising an inlet channel 1, a wetland treatment zone 4, and an outlet channel 3 connected in sequence. Each zone is enclosed by barriers. The inlet channel 1 collects wastewater or sewage to be treated and distributes it to the wetland treatment zone 4. The outlet channel 3 collects the treated water flowing out of the wetland treatment zone 4 and discharges it. The wetland treatment zone 4 includes several treatment units 2 arranged in parallel. The inlet of each treatment unit 2 is connected to the inlet channel 1, and the outlet of each treatment unit 2 is connected to the outlet channel 3. Each treatment unit 2 includes several microbial fuel cells connected in series. The microbial fuel cells can directly convert the chemical energy in organic matter into electrical energy output using microorganisms. Since microorganisms consume organic matter, they can improve the system's degradation capacity to a certain extent, thus reducing the probability of clogging. The microbial fuel cells have inlets and outlets at both ends, with electrodes of opposite polarity on the inlet and outlet sides respectively. The inlets and outlets of adjacent microbial fuel cells are detachably connected, creating a flow channel for the treated water. The electrode leads of adjacent microbial fuel cells with opposite polarities can be detachably connected, enabling series connection of each microbial fuel cell. This improves the output voltage / current and ensures the utilization of electrical energy. Simultaneously, different processing units 2 are connected in parallel, allowing for variations in series-parallel combinations to meet different voltage and current requirements of external circuits, thus offering wider adaptability. This invention uses microbial fuel cells connected in series to form processing units 2, and several processing units 2 connected in parallel to form a wetland treatment zone 4. This enhances the organic matter degradation capacity and rate of the wetland system using microbial fuel cells. Furthermore, when the system becomes clogged, only the clogged microbial fuel cell needs to be replaced, avoiding the need for complete replacement of the entire artificial wetland system, thus reducing operation and maintenance costs. Additionally, replacing the microbial fuel cell at the clogged location avoids the disruption of electron / proton transport and increased internal resistance caused by the clog, facilitating continuous electrical energy output. Therefore, this invention solves the wetland clogging problem, improves wetland treatment capacity, and converts organic matter into electrical energy for output and utilization.

[0038] like Figures 3-5As shown, microbial fuel cells can be divided into type A modules 21, type B modules 22, and type C modules 23 according to their different connection parts. Type A module 21 has a first connection part 211 at both ends, type B module 22 has a second connection part 221 at both ends, and type C module 23 has a first connection part 211 and a third connection part 231 at both ends. The first connection part 211 connects to the second connection part 221, connecting type A module 21 and type B module 22, or connecting type C module 23 and type B module 22. The third connection part 231 connects to the inlet channel 1, connecting type C module 23 to the inlet channel 1, or connects to the outlet channel 3, connecting type C module 23 to the outlet channel 3. Thus, through the above arrangement, any series combination from CBABC to CBABA...ABC can be formed to create a processing unit 2. Figure 9 As shown, they can be combined into a structure where the water inlet channel 1 passes through the processing unit 2 in the form of CBABABC and then reaches the water outlet channel 3.

[0039] like Figures 3-7 As shown, the first connecting part 211 may include a card plate, first holes 2113 distributed on the card plate, and a conductive plug 2112 disposed in the middle of the card plate. The first holes 2113 can serve as either an inlet or an outlet depending on their position and the direction of water flow. The second connecting part 221 includes a card slot that mates with the card plate, second holes 2213 distributed on the card slot, and a conductive insert 2212 disposed in the middle of the card slot. The second holes 2213 can serve as either an inlet or an outlet depending on their position and the direction of water flow. The conductive plug 2112 can serve as either a cathode or an anode, and the conductive insert 2212 can also serve as either a cathode or an anode. Furthermore, the interconnected conductive plug 2112 and conductive insert 2212 have opposite electrodes to achieve series connection of the circuit after insertion. The conductive plug 2112 can be vertically inserted into the conductive insert 2212 from top to bottom to achieve conductivity, thereby enabling synchronous connection after the card plate and card slot are inserted and connected.

[0040] The card slot may include sliding grooves 2214 on both sides and a limiting groove 2215 at the bottom, that is, the card slot as a whole forms a U-shaped structure (see reference). Figure 4(As shown). The card plate has a first insertion part on each side corresponding to the sliding groove 2214, and a second insertion part on the bottom corresponding to the limiting groove 2215. When the card plate is inserted into the slot, it is inserted from top to bottom through the opening of the U-shaped structure of the slot. The sliding grooves 2214 on both sides provide lateral limiting and guidance, while the limiting groove 2215 at the bottom provides downward limiting. This prevents further movement after insertion, ensuring the accuracy of different microbial fuel cell connection positions. Additionally, it allows for quick positioning, facilitates installation and disassembly, and provides convenient alignment for the conductive plug 2112 and the conductive socket 2212. After the card plate and slot are connected, a semi-enclosed structure is formed at the bottom and sides, connecting the first hole 2113 and the second hole 2213 within the semi-enclosed structure, ensuring a tight connection and allowing water to flow smoothly according to the series sequence of the microbial fuel cells, thus ensuring the treatment effect of the wetland system.

[0041] The first insertion part has several rollers 2111 arranged sequentially along the insertion direction. The rolling direction of the rollers 2111 is consistent with the insertion direction of the first insertion part. A slide rail 2211 is provided on one side of the slide groove 2214 at a position corresponding to the rollers 2111. The rollers 2111 can roll in the slide rail 2211, which can further constrain the relative position of the card plate and the card slot. At the same time, by setting the rollers 2111, the ease of insertion and removal process can be improved, and the positioning of the card plate and card slot assembly and disassembly can be made accurate, fast and labor-saving. The vertical loading and unloading connection method further improves the convenience of installing and disassembling the card plate and card slot.

[0042] like Figures 6-7 As shown, rubber pads 2216 are provided on the other side of the slide groove 2214 and the other side of the limiting groove 2215. After the roller 2111 enters the slide groove 2211, it can attach the back of the first insertion part to the rubber pad 2216 to form a relatively closed semi-enclosed communication space, which further improves the sealing of the connection between adjacent microbial fuel cells.

[0043] like Figure 8 As shown, the third connecting part 231 may include a fixing ring 2312, and guide rods 11 are provided at the water inlet channel 1 and the water outlet channel 3. When installing the C-type module 23, it is inserted from top to bottom. At this time, the fixing ring 2312 moves downward and can fit into the guide rod 11. That is, through the cooperation of the guide rod 11 and the fixing ring 2312, the C-type module 23 can be successfully positioned and installed.

[0044] like Figure 5 and Figure 8As shown, the third connecting part 231 includes a downward-facing socket 2311 communicating with the interior of the microbial fuel cell. The socket 2311 is used as either an inlet or outlet depending on whether it is connected to the inlet channel 1 or the outlet channel 3. Both the inlet channel 1 and the outlet channel 3 are connected to vertically upward-facing water pipes 12. The socket 2311 is inserted downwards into the water pipe 12 to achieve communication. A rubber water-stop ring can be installed at the socket 2311 to achieve a seal on the pipe wall after the water pipe 12 is inserted. A switch valve is installed on the water pipe 12. When it is necessary to disassemble the C-type module 23, the switch valve can be closed first, the C-type module 23 can be removed for replacement or flushing, and then the switch valve can be opened again after reinstallation. Since the processing units 2 are arranged in parallel and operate relatively independently, when removing the clogged microbial fuel cell for replacement / flushing, only the switch valve of the corresponding processing unit 2 needs to be closed. There is no need to shut down the entire system, so it does not affect the normal operation of other processing units 2, achieving the effect of replacing the packing without stopping the system operation.

[0045] like Figure 2 As shown, the microbial fuel cell includes a packing bed and wetland plants 10. The packing bed includes a support layer 9, a middle matrix layer 8, and an upper matrix layer 7 arranged from bottom to top. The bottom of the middle matrix layer 8 is covered with an anode material 6, and the top of the upper matrix layer 7 is covered with a cathode material 5. The cathode material 5 and the anode material 6 are respectively connected to different electrode leads (which can be conductive plugs 2112 or conductive boxes 2212). The upper matrix layer 7 is planted with wetland plants 10.

[0046] The microbial fuel cell, as a modular wetland tank, can be designed with dimensions of 1.5m × 0.8m × 1.0m (length × width × height), and is made of materials with certain tensile strength, such as ABS or polyvinyl chloride. The support layer 9 is 20cm thick, with a substrate of gravel or crushed stone with a particle size of φ16–30mm; the middle substrate layer 8 is 35cm thick, with a substrate of gravel or zeolite with a particle size of φ4–15mm; the upper substrate layer 7 is 15cm thick, with a substrate of coarse sand or soil with a smaller particle size; wetland plants 10 include reeds, calamus, and canna lilies. An activated carbon layer or graphite blanket, or other conductive material, can be laid on top of the upper substrate layer 7 as the cathode material 5, and an activated carbon layer or graphite blanket, or other conductive material, can be laid at the bottom of the middle substrate layer 8 as the anode material 6.

[0047] Each microbial fuel cell forms a modular wetland. When wastewater flows through this wetland, it is purified through physical processes such as interception, filtration, and adsorption in the substrate layer, biodegradation by microorganisms attached to the substrate and root surface, absorption by wetland plants 10, and the rhizosphere effect. The anaerobic zone in the lower layer of the wetland constitutes the anode chamber of the microbial fuel cell. Electrogenic bacteria attached to the anode material 6 oxidize and degrade organic matter in the wastewater, producing electrons and protons. Electrons are connected to the cathode material 5 of another module via the anode material 6 and external wires, while protons flow upwards with the wastewater to the cathode material 5. The upper layer of the wetland forms an aerobic zone under the action of air reoxygenation and oxygen secretion from plant roots, constituting the cathode chamber of the microbial fuel cell. Protons undergo an electrode reaction with the participation of oxygen, turning into water. The above process achieves both wastewater purification and the formation of a microbial fuel cell. Through the modular device of this invention, on the one hand, the oxidation-reduction potential difference between the anode and cathode chambers forms a voltage, realizing electrical energy output. On the other hand, the accelerated electron flow inside the microbial fuel cell helps supply electrons to organic matter, enhancing the organic matter degradation capacity and degradation rate of the wetland system.

[0048] In summary, this invention, through the organic combination of modularity and microbial fuel cells, mutually enhances the anti-clogging, pollutant degradation, and power output capabilities, resulting in a significant improvement in all aspects compared to when they are not combined.

[0049] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A modular microbial fuel cell type constructed wetland system characterized by: The system includes an inlet channel, a wetland treatment area, and an outlet channel connected in sequence. The wetland treatment area includes several treatment units arranged in parallel. The inlet of each treatment unit is connected to the inlet channel, and the outlet of each treatment unit is connected to the outlet channel. Each treatment unit includes several microbial fuel cells connected in series. Each microbial fuel cell has an inlet and an outlet at both ends, and electrode leads with opposite polarities are provided on the inlet and outlet sides, respectively. The inlets and outlets of adjacent microbial fuel cells are detachably connected, and the electrode leads with opposite polarities of adjacent microbial fuel cells are also detachably connected. The microbial fuel cell is divided into type A, type B and type C modules according to the different connection parts. Type A module is provided with a first connection part at both ends, type B module is provided with a second connection part at both ends, and type C module is provided with a first connection part and a third connection part at both ends. The first connection part is connected to the second connection part, and the third connection part is connected to the inlet channel or the outlet channel. The first connecting part includes a card plate, a first hole distributed on the card plate, and a conductive plug disposed in the middle of the card plate. The second connecting part includes a card slot that mates with the card plate, a second hole distributed on the card slot, and a conductive insert disposed in the middle of the card slot. The conductive plug and the conductive insert are respectively connected to different electrodes, and the conductive plug and the conductive insert can be connected after the card plate and the card slot are plugged in. The card slot includes sliding grooves on both sides and a limiting groove at the bottom. The card plate has a first insertion part corresponding to the sliding groove on both sides and a second insertion part corresponding to the limiting groove at the bottom. The first insertion part is provided with a plurality of rollers arranged in sequence along the insertion direction. One side of the slide groove is provided with a slide path corresponding to the position of the roller. The other side of the slide groove and the other side of the limiting groove are provided with rubber pads. After the roller enters the slide path, it will press the back of the first insertion part against the rubber pad.

2. The modular microbial fuel cell-type constructed wetland system according to claim 1, characterized in that: The third connecting part includes a fixing ring, and guide rods are provided at the water inlet channel and the water outlet channel. The fixing ring can be inserted into the guide rods when it moves downward.

3. The modular microbial fuel cell-type constructed wetland system according to claim 2, characterized in that: The third connection part includes a downward-facing socket that communicates with the interior of the microbial fuel cell. Both the water inlet channel and the water outlet channel are connected to a vertically upward-facing water pipe. The water pipe is equipped with a switch valve. The socket is inserted downward into the water pipe to achieve communication.

4. The modular microbial fuel cell-type constructed wetland system according to claim 1, characterized in that: The microbial fuel cell includes a packing bed and wetland plants. The packing bed includes a support layer, a middle matrix layer, and an upper matrix layer arranged from bottom to top. The bottom of the middle matrix layer is covered with an anode material, and the top of the upper matrix layer is covered with a cathode material. The cathode material and the anode material are respectively connected to different electrode leads. The upper matrix layer is planted with wetland plants.

5. The modular microbial fuel cell-type constructed wetland system according to claim 4, characterized in that: The supporting layer is 20cm thick, and the matrix is ​​selected with a particle size of... Gravel and crushed stone of ~30mm; the middle matrix layer is 35cm thick, and the matrix is ​​selected with a particle size of ~30mm. Gravel or zeolite with a particle size of ~15mm; the upper matrix layer is 15cm thick, and the matrix is ​​coarse sand or soil with a small particle size; the wetland plants are reeds, calamus, and canna; the cathode material and the anode material are activated carbon layer or graphite blanket.

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