Microbial electrochemical reaction device and repair method for in-situ remediation of organic polluted sludge

Abstract

The present application discloses a microbial electrochemical reaction device for in-situ remediation of organically contaminated sediments, comprising: a substrate, which is cylindrical and comprises an inner surface facing the inside of the cylinder and an outer surface facing the outside of the cylinder, and the substrate comprises a straight section and a flared section that are butt-jointed along the axis of the cylinder; a conductive layer, which is arranged on the inner and outer surfaces of the substrate; an electricity-generating microbial module, which is arranged on the outer surface of the straight section of the substrate; and an oxygen-generating moss algae module, which is arranged on the inner surface of the flared section of the substrate.

Description

Technical Field

[0001] The present application relates to the technical field of water environment treatment, and in particular to a microbial electrochemical reaction device and a repair method for in-situ repair of organically contaminated sediment. Background Art

[0002] In the field of endogenous pollution control technology, in-situ remediation is less expensive and more sustainable than ex-situ dredging. The main goal of in-situ remediation of sediment is to control the entry of pollutants in the sediment layer into the overlying water body and the tissues of aquatic animals, reduce the bioactive components of pollutants in the sediment, and create a new benthic ecosystem for aquatic plants and animals.

[0003] At present, there are three common methods for in situ remediation of sediments, namely: (1) using adsorption or passivation materials to cover the surface of the sediment, and the active sites on the surface of the adsorption materials bind to the pollutants, or directly react chemically with the pollutants to generate stable, water-insoluble products; (2) using sediment improvers whose main components are microorganisms that can use pollutants as a source of matter and energy, and degrading or converting pollutants in the sediment into harmless substances under conditions of sufficient dissolved oxygen and suitable temperature; (3) using engineering materials such as sand and gravel to directly cover the sediment, and by controlling the resuspension of the sediment, it plays a role in separating the sediment layer and the overlying water body.

[0004] However, there are a series of difficult-to-solve problems in the implementation of the above three methods: (1) After the adsorption and passivation type remediation materials are saturated, the pollutants are released again. At the same time, the nutrients and sediment in the overlying water body are reversely deposited to increase the thickness of the bottom mud layer; (2) Degradation type remediation agents are mostly aerobic bacteria, which must be aerated in large quantities when used. Not only is the energy consumption high and the remediation cycle long, but it is also easy to cause the bottom mud to resuspension; (3) Sand and gravel paving has a large effective thickness, which squeezes the reservoir capacity and affects the waterway, and has a poor blocking effect on pollutants.

[0005] In response to the above problems, some new technologies have gradually emerged. Among them, sediment microbial fuel cells (SMFCs) can use the electrogenic bacteria in the sediment as catalysts to degrade organic pollutants in the sediment and generate electricity at the same time. This technology buries carbon felt in the sediment as an anode and places another carbon felt as a cathode in the overlying water body. The positive and negative electrodes are connected by wires and connected to electrical components at the same time. However, since part of its energy is converted into electrical energy, the energy used for pollutant degradation becomes correspondingly less, which limits the large-scale application of this technology in in-situ sediment remediation.

[0006] On this basis, by abandoning its ability to convert electrical energy output, all the converted energy is used for pollutant degradation. This method is called sediment microbial electrochemical ventilation tube technology (SMES), that is, half of a cylindrical graphite electrode is inserted into the anaerobic sediment, and the other half is exposed to the overlying water body with oxygen. There is no electrical component in the middle, so that the entire circuit is short-circuited, so that the microbial electrochemical energy is all used to degrade organic pollutants in the anaerobic sediment to provide electrons. The electrons are conducted to the overlying water body in the aerobic environment through a single graphite electrode, and the oxygen attached to the graphite electrode is used as an electron acceptor to finally generate water. With the power-producing microorganisms as the driving force, a single graphite electrode conducts electrons, so that the process is repeated continuously and the organic pollutants in the sediment are continuously degraded. However, the graphite electrodes used in this technology have a high manufacturing cost. When encountering a thick sediment layer or a deep overlying water body, if the ideal reaction state is to be achieved, the graphite electrode will be very long to pass through the anaerobic and aerobic zones, resulting in poor economic efficiency. In addition, the dissolved oxygen concentration in the water body polluted by sediment is low, which makes the cathode reaction efficiency of the graphite electrode extremely low, resulting in little in-situ remediation effect. These technical difficulties make the existing microbial electrochemical ventilation tubes unable to be directly used for sediment in-situ remediation. Summary of the invention

[0007] Based on this, the present application provides a microbial electrochemical reaction device, which is simple to deploy and can continuously and efficiently degrade organic pollutants in sediments. It can also be used as an artificial fish nest to improve biodiversity while repairing polluted sediments in situ.

[0008] A microbial electrochemical reaction device for in-situ remediation of organic polluted sludge, comprising:

[0009] A base body, the base body is cylindrical, the base body comprises an inner surface facing the inside of the cylinder body and an outer surface facing the outside of the cylinder body, and the base body comprises a straight section and a flared section that are butt-jointed along the axis of the cylinder body;

[0010] A conductive layer is arranged on the inner surface and the outer surface of the substrate;

[0011] An electricity-generating microbial module is disposed on the outer surface of the straight tube section of the substrate;

[0012] The oxygen-producing moss algae module is arranged on the inner surface of the expanded section of the substrate.

[0013] Several optional methods are also provided below, but they are not intended to be additional limitations on the above-mentioned overall solution, but are merely further supplements or preferences. Under the premise that there are no technical or logical contradictions, each optional method can be combined with the above-mentioned overall solution separately, and multiple optional methods can also be combined.

[0014] Optionally, the outer surface of the straight cylinder section of the substrate is provided with a plurality of areas distributed circumferentially, each area is provided with a plurality of grooves arranged along the axis direction of the cylinder, and a corresponding electricity-generating microbial module is arranged in each groove.

[0015] Optionally, the electrogenic microbial module includes: a solid culture medium and electrogenic microbial strains, wherein the electrogenic microbial strain is at least one of Rhodopseudomonas palustris, Ochrobactrum hominis, Gluconobacter oxidans, Rhodopseudomonas iron-reducing, Comamonas denitrifying, Shewanella, Pseudomonas aeruginosa, Klebsiella pneumoniae, Geobacter sulfurreducing, Geobacter metalloreducing, Clostridium butyricum, Saccharomyces cerevisiae, and Hansenula anomala.

[0016] Optionally, the solid culture medium is at least one of yeast extract, peptone, NaCl, phosphate, sodium alginate, chitosan, starch, pectin, agar, carbonate, and nitrate.

[0017] Optionally, the inner surface of the expanded section of the base is provided with a plurality of installation grooves, each of which is arranged around the axis of the cylinder, and a corresponding oxygen-producing moss algae module is arranged in each of the installation grooves.

[0018] Optionally, the moss algae in the oxygen-producing moss algae module is at least one of large feather moss, small feather moss, large gray moss, small gray moss, bristle algae, hydrographis, and water sponge.

[0019] Optionally, the conductive layer is prepared by uniformly coating the inner and outer surfaces of the substrate with a conductive coating, wherein the conductive coating is at least one of graphite, graphene, silver, copper, and nickel, and the conductive coating contains a binder with a mass fraction of 0.5% to 2%.

[0020] Optionally, the diameter of the straight section of the base is 0.4m to 1m, the maximum diameter of the expanded section of the base is 1.0m to 2m, and the axial length of the base is 1.0m to 2m.

[0021] Optionally, the angle between the side wall of the expansion section and the axis of the cylinder is 40 to 70 degrees.

[0022] The present application also provides a method for in-situ remediation of organic contaminated sediment, comprising:

[0023] At least one of the microbial electrochemical reaction devices is placed in a body of water, wherein the straight section is inserted into the bottom mud and the expanded section is located in the overlying water body. The electricity-producing microbial module on the straight section uses organic matter in the bottom mud as an electron donor, and the oxygen-producing moss algae module produces oxygen as an electron acceptor through photosynthesis, and uses the conductive layer on the surface of the substrate for electron conduction to form an in-situ short-circuit circuit, thereby continuously degrading organic matter in the bottom mud.

[0024] The present application utilizes the short-circuit principle of microbial electrochemical circuits, inserts the straight section of the reaction device into the contaminated sediment, uses the organic matter in the sediment as the electron donor, and extends the flared section end of the reaction device into the overlying water body. The oxygen-producing moss algae module on the inner surface of the flared section produces oxygen through photosynthesis, and the generated oxygen acts as an electron acceptor, and conducts electrons through the conductive layer on the surface of the reaction device body, forming an in-situ short-circuit circuit, cyclically degrading organic pollutants in the sediment. At the same time, it can be used as an artificial fish nest, which can improve biodiversity while repairing the contaminated sediment in situ. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a three-dimensional top view of the microbial electrochemical reaction device of the present application;

[0026] Figure 2 It is a front view of the microbial electrochemical reaction device;

[0027] Figure 3 It is a top view of the microbial electrochemical reaction device;

[0028] Figure 4 It is a three-dimensional bottom view of the microbial electrochemical reaction device;

[0029] Figure 5 The cylinder wall structure diagram of the microbial electrochemical reaction device;

[0030] Figure 6 The structure diagram of the experimental device for the blank control group;

[0031] Figure 7 Microbial electrochemical reaction device action group experimental device structure diagram;

[0032] Figure 8 The trend of TOC content in sediment over time;

[0033] Fig. 9 The trend of NH3-N content in sediment over time;

[0034] Fig.10 The trend of TN content in sediment over time;

[0035] Fig.11 The TOC content of sediment in the area affected by the microbial electrochemical reaction device;

[0036] Fig.12 TOC content of sediment in the area affected by the control cylinder.

[0037] In the figure: 1. reaction device; 2. electricity-producing microorganism module; 3. oxygen-producing moss algae module; 1a. flared section; 1b. straight section; 4. substrate; 5. conductive layer; 6. overlying water layer; 7. contaminated sediment layer; 8. sampling tube; 9. anti-evaporation cover; 10. plexiglass tube. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0039] In order to better describe and illustrate the embodiments of the present application, reference may be made to one or more drawings, but the additional details or examples used to describe the drawings should not be considered as limiting the scope of the invention of the present application, any of the currently described embodiments or preferred methods.

[0040] It should be noted that when a component is referred to as being "connected" to another component, it may be directly connected to the other component or there may be a central component. When a component is referred to as being "disposed on" another component, it may be directly disposed on the other component or there may be a central component at the same time.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0042] See also Figure 1 to Figure 4 As shown, a microbial electrochemical reaction device for in-situ remediation of organic polluted sediments comprises:

[0043] The base body is cylindrical and includes an inner surface facing the inside of the cylinder and an outer surface facing the outside of the cylinder. The base body includes a straight section 1b and a flared section 1a that are butt-jointed along the axis of the cylinder;

[0044] A conductive layer is provided on the inner surface and the outer surface of the substrate;

[0045] The electricity-generating microorganism module 2 is arranged on the outer surface of the straight tube section 1b of the substrate;

[0046] The oxygen-producing moss algae module 3 is arranged on the inner surface of the expanded section 1a of the base.

[0047] The microbial electrochemical reaction device for in-situ remediation of organic contaminated sludge provided in the present application degrades organic pollutants in the sludge in-situ through the electrochemical reaction of microorganisms, and starts and sustains the electrochemical reaction through the loaded electricity-producing microbial module 2 and the oxygen-producing moss algae module 3, thereby continuously remediating the contaminated sludge without other external energy input.

[0048] The straight section 1b (as an anode) of the microbial electrochemical reaction device 1 is inserted into the contaminated sediment, with the organic matter in the sediment as the electron donor, and the expanded section 1a (as a cathode) of the microbial electrochemical reaction device 1 extends into the overlying water body. The oxygen-producing moss algae module 3 on the inner surface of the expanded section 1a produces oxygen through photosynthesis. The generated oxygen acts as an electron acceptor and conducts electrons through the conductive layer of the microbial electrochemical reaction device 1, forming an in-situ short-circuit circuit, and cyclically degrading the organic pollutants in the sediment.

[0049] The microbial electrochemical reaction device provided in the present application adopts a structure imitating trumpet coral, which can not only be easily inserted into the bottom mud layer and easily placed, but also its cylindrical internal cavity can be used as a place for fish to forage and take shelter. At the same time, the expanded section 1a has an oxygen-producing algae module with abundant oxygen content, and the moss mesh layer on the inner surface is extremely easy to attach zooplankton as fish bait. Therefore, it can be used as an artificial fish nest, which is not only beautiful and ecological, but also improves biodiversity while repairing contaminated bottom mud in situ.

[0050] The base body is made of an inert material with a density greater than that of water to prevent it from gradually floating during use due to low density. The base body mainly plays a rigid supporting role. In order to reduce costs, the base material is at least one of resin concrete, steel fiber concrete, polyvinyl chloride, and ceramics. For ceramic materials, clay is fired to form, and for other materials, mold casting can be used.

[0051] See also Figure 1 , Figure 2 As shown, the outer surface of the straight cylinder section 1b of the substrate is provided with a plurality of areas distributed around the circumference, each area is provided with a plurality of grooves arranged along the axis direction of the cylinder, and a corresponding electricity-generating microbial module 2 is arranged in each groove.

[0052] The groove is a rectangular groove, and the corresponding electricity-generating microbial module 2 is also made into a strip with a corresponding shape and embedded in the groove. The electricity-generating microbial module 2 is used to start the microbial electrochemical reaction.

[0053] The electrogenic microorganism module 2 includes: a solid culture medium and electrogenic microorganism strains, wherein the electrogenic microorganism strain is at least one of Rhodopseudomonas palustris, Ochrobacterium hominis, Gluconobacter oxidans, Rhodopseudomonas iron-reducing, Comamonas denitrificans, Shewanella, Pseudomonas aeruginosa, Klebsiella pneumoniae, Geobacter sulfurreducens, Geobacter metalloreducens, Clostridium butyricum, Saccharomyces cerevisiae, and Hansenula anomala. The electrogenic microorganism strain may be one species or two or more species in combination.

[0054] The solid culture medium is at least one of yeast extract, peptone, NaCl, phosphate, sodium alginate, chitosan, starch, pectin, agar, carbonate and nitrate.

[0055] The culture medium can be one kind or two or more kinds of compound culture medium, which is mainly determined by the species of bacteria. The electrogenic microorganisms are embedded in the solid culture medium in a gelatinous state, filled and embedded in the grooves corresponding to the outer surface of the straight section 1b, and after entering the bottom mud, the electrogenic microorganisms use the nutrients in the solid culture medium under the action of water to quickly form a biofilm in the straight section 1b as the anode. After the start-up period, the organic pollutants in the bottom mud are completely metabolized and generate electrons.

[0056] See also Figure 1 , Figure 3 As shown, the inner surface of the expanded section 1a of the base is provided with a plurality of installation grooves, each of which is arranged around the axis of the cylinder, and a corresponding oxygen-producing moss algae module 3 is arranged in each of the installation grooves.

[0057] The moss algae in the oxygen-producing moss algae module 3 include bryophytes, algae, mosses, etc. For example, the moss algae in the oxygen-producing moss algae module 3 is at least one of large feather moss, small feather moss, large gray moss, small gray moss, bristle algae, hydrographis, and water sponge.

[0058] The installation groove is a rectangular groove, and the oxygen-producing moss algae module 3 is made into a strip with a corresponding shape and embedded in the installation groove. The inner surface of the expanded section 1a can better receive sunlight, and the oxygen-producing moss algae module installed here can use sufficient sunlight for photosynthesis.

[0059] The oxygen-producing moss algae module 3 produces oxygen through photosynthesis underwater. After it grows into a stacked mesh structure, it can absorb and capture the generated oxygen on the inner surface of the expanded section 1a serving as the cathode, thereby enhancing the cathode reaction.

[0060] See also Figure 5 As shown, the conductive layer 5 is prepared by uniformly coating the inner and outer surfaces of the substrate 4 with a conductive coating, the conductive coating is at least one of graphite, graphene, silver, copper, and nickel, and the conductive coating contains a binder with a mass fraction of 0.5% to 2%. The inner and outer surfaces of the substrate 4 are both provided with a conductive layer 5, and the conductive layer 5 is used to conduct electrons. The binder can be pectin or xanthan gum.

[0061] See also Figure 2 As shown, the diameter D2 of the straight section 1b of the base is 0.4m to 1m, the maximum diameter D1 of the expanded section 1a of the base is 1.0m to 2m, and the axial length H of the base is 1.0m to 2m.

[0062] See also Figure 2 As shown, the angle α between the side wall of the expanded section 1a and the axis of the cylinder is 40 to 70 degrees. The larger the angle between the expanded section 1a and the axis of the cylinder, the closer the expanded section 1a is to the horizontal plane, and the more sunlight can be received to enable the oxygen-producing algae module located on the inner surface of the expanded section 1a to photosynthesize.

[0063] A method for in-situ remediation of organic polluted sludge, comprising:

[0064] At least one of the microbial electrochemical reaction devices 1 is placed in a water area, with the straight section 1b inserted into the bottom mud and the expanded section 1a located in the overlying water body. The electricity-producing microbial module on the straight section uses organic matter in the bottom mud as an electron donor, and the oxygen-producing moss algae module produces oxygen as an electron acceptor through photosynthesis, and uses the conductive layer on the surface of the substrate for electron conduction to form an in-situ short-circuit circuit, thereby continuously degrading organic matter in the bottom mud.

[0065] Performance Testing

[0066] The bottom sludge in the following performance test was taken from the mixed discharge outlet of a river in a certain urban area of ​​Chongqing, which illustrates the removal effect of the microbial electrochemical reaction device provided in this application on TOC, NH3-N and TN.

[0067] Six plexiglass tubes with a diameter of 300 mm and a height of 400 mm were made and divided into two groups, with three tubes in each group. One group was a blank control group (only contaminated sediment and overlying water), and the other group was a microbial electrochemical reaction device action group (except for the contaminated sediment and overlying water, the microbial electrochemical reaction device (that is, the microbial electrochemical reaction cylinder in the figure) was inserted into the sediment, with dimensions of 131 mm in diameter for the cathode expansion section, 60 mm in diameter for the anode straight section, and a total height of 136 mm for the microbial electrochemical reaction device).

[0068] The three organic glass tubes in each group were used for parallel experiments. The thickness of all polluted sediment layers was 150 mm, and the thickness of the overlying water body was 200 mm. The straight section of the anode was immersed in the sediment layer, and the end of the cathode expansion section was exposed in the overlying water layer. Figure 6 This is the structure diagram of the experimental device for the blank control group. Figure 7 The structure diagram of the experimental device of the microbial electrochemical reaction device action group includes a plexiglass tube 10 with a polluted sediment layer 7 and an overlying water layer 6, an anti-evaporation cover 9 arranged on the top of the plexiglass tube 10, and a sampling tube 8 arranged on the side wall of the plexiglass tube 10.

[0069] Before the experiment, the concentrations of TOC, NH3-N and TN in the sediment were detected. After the start of the experiment, the concentrations of TOC, NH3-N and TN in the sediment were detected through sampling tubes on the 10th, 20th, 30th, 40th, 50th and 60th days respectively. The temperature was 20-25℃ and the light was natural.

[0070] Figure 8 , Fig. 9 , Fig.10The trend of TOC, NH3-N and TN content in the sludge in the blank group and the microbial electrochemical reaction device group over time. As can be seen from the figure, as time goes on, the TOC, NH3-N and TN content in the microbial electrochemical reaction device group gradually decreases, while the change in the blank control group is not obvious. Under the action of the microbial electrochemical reaction device, after 60 days of reaction, the TOC removal rate can reach 38.57%, the NH3-N removal rate can reach 65.53%, and the TN removal rate can reach 23.21%. It shows that the microbial electrochemical reaction device has a good remediation effect on organic matter in contaminated sludge, and from the trend, it can be seen that the removal rate will gradually increase over time because the reaction is a self-sustaining reaction.

[0071] In order to verify the effect of the microbial electrochemical reaction device in the present application in an actual engineering application environment, a reaction device was produced (the dimensions were a cathode expansion section diameter of 1.31 m, an anode straight section diameter of 0.60 m, and a total height of 1.36 m), and a control cylinder was produced with the same dimensions (the inner and outer surfaces were not coated with conductive paint, and no electricity-producing microbial modules and oxygen-producing moss algae modules were embedded).

[0072] A sewage pond in the urban-rural fringe area of ​​Chongqing was used as a demonstration area (the average thickness of the polluted sludge layer in the sewage pond was 0.8-1.5 m, and the TOC content was 17-24 g / kg). The microbial electrochemical reaction device and the control cylinder (the two were 125 m apart and did not affect each other) were inserted into the sludge layer. With the insertion point as the center of the circle, sampling points were set every 5 m in the four directions of east, west, south and north. After 30 days of reaction, the sludge 10-20 cm below the mud-water interface was collected for TOC content detection.

[0073] The results are as follows Fig.11 ( Fig.11 The position of the reaction tube in the middle is the position of the microbial electrochemical reaction device) and Fig.12 As shown in the figure, it can be seen that the TOC content of the bottom mud around the microbial electrochemical reaction device is obviously regularly distributed, but as it moves away from the reaction device, its content gradually increases. Its effective radius is about 10m and its range is about 314m 2 In contrast, there was no obvious pattern in the sediment content around the control cylinder, which was almost the same as the surrounding background content, indicating that the control cylinder had no effect on the sediment in the area.

[0074] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0075] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A microbial electrochemical reaction device for in-situ remediation of organically contaminated sediment, characterized in that: include: A base body, the base body is cylindrical, the base body comprises an inner surface facing the inside of the cylinder body and an outer surface facing the outside of the cylinder body, and the base body comprises a straight section and a flared section that are butt-jointed along the axis of the cylinder body; A conductive layer is arranged on the inner surface and the outer surface of the substrate; An electricity-generating microbial module is disposed on the outer surface of the straight tube section of the substrate; The oxygen-producing moss algae module is arranged on the inner surface of the expanded section of the substrate.

2. The microbial electrochemical reaction device for in-situ remediation of organic polluted sediment according to claim 1 is characterized in that: The outer surface of the straight cylinder section of the substrate is provided with a plurality of areas distributed circumferentially, each area is provided with a plurality of grooves arranged along the axis direction of the cylinder, and a corresponding electricity-generating microbial module is arranged in each groove.

3. The microbial electrochemical reaction device for in-situ remediation of organic polluted sediment according to claim 1 is characterized in that: The electrogenic microbial module comprises: a solid culture medium and electrogenic microbial strains, wherein the electrogenic microbial strain is at least one of Rhodopseudomonas palustris, Ochrobactrum hominis, Gluconobacter oxidans, Rhodopseudomonas iron-reducing, Comamonas denitrifying, Shewanella, Pseudomonas aeruginosa, Klebsiella pneumoniae, Geobacter sulfur-reducing, Geobacter metallo-reducing, Clostridium butyricum, Saccharomyces cerevisiae, and Hansenula anomala.

4. The microbial electrochemical reaction device for in-situ remediation of organic polluted sediment according to claim 3 is characterized in that: The solid culture medium is at least one of yeast extract, peptone, NaCl, phosphate, sodium alginate, chitosan, starch, pectin, agar, carbonate and nitrate.

5. The microbial electrochemical reaction device for in-situ remediation of organic polluted sediment according to claim 1, characterized in that: The inner surface of the expanded section of the base body is provided with a plurality of installation grooves, each of which is arranged around the axis of the cylinder body, and a corresponding oxygen-producing moss algae module is arranged in each of the installation grooves.

6. The microbial electrochemical reaction device for in-situ remediation of organic polluted sediment according to claim 1, characterized in that: The moss algae in the oxygen-producing moss algae module is at least one of large feather moss, small feather moss, large gray moss, small gray moss, bristle algae, hydrodiplophyte, and water spiral.

7. The microbial electrochemical reaction device for in-situ remediation of organic polluted sediment according to claim 1 is characterized in that: The conductive layer is prepared by uniformly coating the inner and outer surfaces of the substrate with a conductive coating, wherein the conductive coating is at least one of graphite, graphene, silver, copper, and nickel, and the conductive coating contains a binder with a mass fraction of 0.5% to 2%.

8. The microbial electrochemical reaction device for in-situ remediation of organic polluted sediment according to claim 1, characterized in that: The diameter of the straight section of the base is 0.4m-1m, the maximum diameter of the expanded section of the base is 1.0m-2m, and the axial length of the base is 1.0m-2m.

9. The microbial electrochemical reaction device for in-situ remediation of organic polluted sediment according to claim 1, characterized in that: The included angle between the side wall of the expansion section and the axis of the cylinder is 40 to 70 degrees.

10. A method for in-situ remediation of organically contaminated sediment, characterized in that: include: At least one microbial electrochemical reaction device as described in any one of claims 1 to 9 is placed in a water area, wherein the straight section is inserted into the bottom mud, and the expanded section is located in the overlying water body. The electricity-producing microbial module on the straight section uses organic matter in the bottom mud as an electron donor, and the oxygen-producing moss algae module produces oxygen as an electron acceptor through photosynthesis, and uses the conductive layer on the surface of the substrate for electron conduction to form an in-situ short-circuit circuit, thereby continuously degrading organic matter in the bottom mud.

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