Stackable microbial fuel cell, energy storage system and method of operation

Abstract

The application discloses a stack type microbial fuel cell for sewage treatment, an energy storage system and a working method, and belongs to the technical field of energy utilization in sewage treatment. The stack type microbial fuel cell is inserted in an anoxic zone of a biological pool of sewage, and comprises a hollow body provided with an air exchange opening. A plurality of microbial fuel cells are arranged on the hollow body in connection. The microbial fuel cell comprises an anode plate and a cathode plate. A plurality of anode plates are fixed to the outer side of the hollow body. A plurality of cathode plates are arranged opposite to the plurality of anode plates and are fixed to the inner side of the hollow body. A floating plate is arranged on the air exchange opening of the hollow body. An air exchange mechanism is arranged on the air exchange opening of the hollow body. The energy storage system and the working method are disclosed. The stack type microbial fuel cell, the energy storage system and the working method are applied to the anoxic zone of the biological pool of the existing sewage treatment plant, are simple in application, high in energy utilization rate, low in updating cost, and convenient to popularize.

Description

Technical Field

[0001] This invention relates to the field of energy utilization technology in wastewater treatment, and in particular to a stacked microbial fuel cell, energy storage system and working method for wastewater treatment. Background Technology

[0002] With the accelerating pace of industrialization and urbanization, water environments in most areas have deteriorated, leading to water shortages. To effectively improve regional water environments and achieve green and sustainable water resource development, wastewater treatment plants are used to treat industrial wastewater. Existing wastewater treatment plants employ multi-stage treatment systems. Generally, wastewater undergoes primary physical treatment to remove suspended solids, followed by the removal of colloidal and dissolved organic pollutants. Current technologies utilize biological treatment ponds, which leverage the metabolic functions of microorganisms to degrade and transform dissolved and colloidal organic pollutants into harmless substances, thus purifying the wastewater. In modern wastewater treatment plants, biological treatment ponds can be divided into anaerobic, aerobic, and anoxic zones, where different types of microorganisms simultaneously degrade the wastewater. In an anaerobic environment, polyphosphate-accumulating bacteria carry out anaerobic phosphorus release biochemical reactions; nitrifying bacteria are aerobic bacteria, mainly found in aerobic tanks or contact oxidation tanks in wastewater treatment processes, where aeration equipment is added to provide sufficient oxygen for the consuming bacteria; denitrifying bacteria mainly denitrify the mixed liquor returned from the aerobic tank in anoxic water with dissolved oxygen below 0.5 mg / L and pH between 6 and 9. Denitrifying bacteria are mostly heterotrophic or facultative anaerobic bacteria, such as denitrifying bacilli and Stellaria media.

[0003] Existing technologies utilize microbial fuel cells for wastewater treatment to achieve energy recovery. For example, patent number 201310177939.0 discloses a microbial fuel cell for wastewater treatment and energy recovery. However, many problems still exist in existing technologies:

[0004] (1) The actual environment of the microbial fuel cell was not considered. The oxygen content of the wastewater has a significant impact on the working efficiency of the microbial fuel cell. The basic working principle of the microbial fuel cell is: In the anaerobic environment of the anode chamber, organic matter is decomposed by microorganisms and releases electrons and protons. Electrons are effectively transferred between the biological components and the anode through a suitable electron transfer medium and are transferred to the cathode through the external circuit to form an electric current. Protons are transferred to the cathode through the proton exchange membrane. The oxidant (usually oxygen) is reduced and combines with protons to form water at the cathode.

[0005] (2) At the same time, most microbial fuel cells require separate manufacturing of treatment systems when treating wastewater, which cannot be easily implemented in existing wastewater treatment processes. Summary of the Invention

[0006] The purpose of this invention is to provide a stacked microbial fuel cell, energy storage system and working method for wastewater treatment, which can be applied to the anoxic zone of the biological pool in existing wastewater treatment plants. It has high energy utilization rate, simple application, low replacement cost and is easy to promote.

[0007] To achieve the above objectives, the present invention provides a stacked microbial fuel cell for wastewater treatment. The stacked microbial fuel cell is inserted into the anoxic zone of a wastewater biological tank. The stacked microbial fuel cell includes at least one hollow body with an air exchange port. Several interconnected microbial fuel cells are arranged on the hollow body. The microbial fuel cell includes an anode plate and a cathode plate. Several anode plates are fixed on the outside of the hollow body, and several cathode plates are arranged opposite to and fixed on the inside of the hollow body. The air exchange port of the hollow body is provided with a float plate and an air exchange mechanism.

[0008] Preferably, the hollow body is a hollow cylinder or a hollow prism, and the height of the hollow body is less than the depth of the anoxic zone of the wastewater biological tank. Several anode plates are evenly fixed to the outside of the hollow body by fasteners, and several cathode plates are fixed to the inside of the hollow body by wastewater drainage pipes. One end of the wastewater drainage pipe is set in the through hole of the hollow body, and a support leg is provided at the bottom of the hollow body.

[0009] Preferably, several microbial fuel cells are connected in series or in parallel via connecting wires.

[0010] Preferably, the ventilation mechanism includes a horn-shaped protective sleeve, a ventilation energy storage battery is fixed to the top of the horn-shaped protective sleeve by a support frame, a ventilation fan is provided below the ventilation energy storage battery, the ventilation fan is electrically connected to the ventilation energy storage battery, the float is annular, and at least one solar panel is provided on the float, the solar panel is electrically connected to the ventilation energy storage battery.

[0011] Preferably, there are two hollow bodies, and the bottoms of the two hollow bodies are connected by a vent pipe.

[0012] An energy storage system based on the aforementioned stacked microbial fuel cell for wastewater treatment includes a microbial power generation unit composed of several stacked microbial fuel cells. The several stacked microbial fuel cells are connected to each other via a fixed-node distributed circuit. The microbial power generation unit is located in the anoxic zone of the wastewater biological pond, and the fixed-node distributed circuit is connected to the energy storage unit.

[0013] Preferably, the fixed-node distributed circuit includes a horizontal circuit section and a vertical circuit section, and the intersection of the horizontal circuit section and the vertical circuit section is a fixed node. Several stacked microbial fuel cells are distributed in a matrix or cross arrangement at the fixed node.

[0014] Preferably, the spacing between adjacent fixed nodes is 1.5-2 times the outer diameter of the floating plate.

[0015] A working method based on the above-mentioned energy storage system includes the following specific steps:

[0016] Step S1: Determine the dimensions of the fixed node distributed circuit based on the dimensions of the anoxic zone and the floating plate of the wastewater biological pond; determine the height of the hollow body based on the depth of the anoxic zone of the wastewater biological pond; assemble the stacked microbial fuel cell; and determine the sealing performance of the hollow body.

[0017] Step S2: The assembled stacked microbial fuel cell is placed on a fixed node of the fixed node distributed circuit and inserted into the anoxic zone of the wastewater biological pond. The fixed node distributed circuit is connected to the energy storage unit.

[0018] Step S3: The anoxic zone of the wastewater biological tank begins operation. Wastewater slowly flows from one end to the other. As it passes through the stacked microbial fuel cell, the microorganisms in the wastewater attach to the anode plate and degrade the organic matter in the wastewater. Electrons generated by the reaction on the anode plate are transported to the cathode plate through connecting wires. Protons generated by the reaction on the anode plate are transported to the cathode plate through the wastewater drainage pipe and react with oxygen in the air on the cathode plate. The electrical energy generated by the reaction of the stacked microbial fuel cell is transported to the energy storage unit through a fixed-node distributed circuit.

[0019] Therefore, the stacked microbial fuel cell, energy storage system, and operating method for wastewater treatment using the above-described structure of the present invention have the following beneficial effects:

[0020] (1) Stacked microbial fuel cells use hollow bodies to directly insert into sewage for sewage treatment and energy recovery at the same time. The structure is simple and easy to promote. At the same time, it has a gas exchange mechanism so that the cathode plate inside the hollow body has enough oxygen to react and improve energy utilization.

[0021] (2) A number of stacked microbial fuel cells are connected by a fixed node distributed circuit and the generated electrical energy is transmitted to the energy storage unit for energy recovery.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 This is a front view of a stacked microbial fuel cell for wastewater treatment according to Embodiment 1 of the present invention;

[0024] Figure 2 This is a three-dimensional view of a stacked microbial fuel cell for wastewater treatment according to Embodiment 1 of the present invention;

[0025] Figure 3This is a schematic diagram of the microbial fuel cell structure in Embodiment 1 of the present invention.

[0026] Figure 4 This is a circuit connection diagram of the positive and negative electrodes of a vertically stacked microbial fuel cell according to the present invention;

[0027] Figure 5 This is a circuit connection diagram of the anode and cathode electrodes of a vertically stacked microbial fuel cell according to the present invention.

[0028] Figure 6 This is a matrix layout diagram of the stacked microbial fuel cell of the present invention;

[0029] Figure 7 This is a diagram showing the cross-arrangement of the stacked microbial fuel cell of the present invention;

[0030] Figure 8 This is a structural diagram of a stacked microbial fuel cell for wastewater treatment according to Embodiment 3 of the present invention.

[0031] Figure Labels

[0032] 1. Hollow body; 11. Ventilation port; 12. Through hole; 13. Support leg; 2. Microbial fuel cell; 21. Anode plate; 22. Cathode plate; 23. Fixing component; 24. Sewage drainage pipe; 3. Float plate; 4. Ventilation mechanism; 41. Horn-shaped protective sleeve; 42. Support frame; 43. Ventilation and energy storage battery; 44. Ventilation fan; 5. Solar panel; 6. Fixed node distributed circuit; 61. Horizontal circuit section; 62. Vertical circuit section; 63. Fixed node; 7. Energy storage unit; 8. Anoxic zone of sewage biological pond; 9. Connecting pipe. Detailed Implementation

[0033] Example

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0036] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0037] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed when in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0038] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] The following describes some embodiments of the present invention in detail with reference to the accompanying drawings.

[0040] Example 1

[0041] like Figure 1-4 As shown, a stacked microbial fuel cell for wastewater treatment is inserted into the anoxic zone 8 of a wastewater biological treatment tank. The stacked microbial fuel cell includes a hollow body 1 (air cathode chamber) with an air exchange port 11. In this embodiment, the hollow body 1 is a hollow cylinder, and its height is less than the depth of the anoxic zone 8 of the wastewater biological treatment tank. This ensures that the length of the hollow cylinder is not too short to accommodate enough microbial fuel cells 2, and that it does not contact the bottom of the anoxic zone 8. Simultaneously, a support leg 13 is provided at the bottom of the hollow body 1 to protect it from low water levels.

[0042] A hollow body 1 is provided with several interconnected microbial fuel cells 2. Each microbial fuel cell 2 includes an anode plate 21 and a cathode plate 22. The anode plates 21 are arranged in four rows and fixed on the outside of the hollow body 1, directly contacting the sewage. Microorganisms attach to their surfaces and degrade organic matter in the sewage, resulting in an anode reaction. The anode plates 21 are fixed to the outside of the hollow body 1 by fasteners 23. The cathode plates 22 are arranged opposite to the anode plates 21 and fixed on the inside of the hollow body 1. The cathode plates 22 are fixed on the inside of the hollow body 1 by sewage drainage pipes 24, one end of which is located in a through hole 12 in the hollow body 1. In this embodiment, the microbial fuel cells 2 in the same row are connected in series by connecting wires, and the anode plates 21 and cathode plates 22 in each vertical row are stacked as a group. The number of anode plates 21 and cathode plates 22 can be determined according to requirements and the size of the hollow cylinder to improve the overall power generation efficiency. The number of anode plates 21 and cathode plates 22 is set according to the actual situation.

[0043] A floating plate 3 is provided at the ventilation port 11 of the hollow body 1, and a ventilation mechanism 4 is provided at the ventilation port 11. The ventilation mechanism 4 includes a horn-shaped protective sleeve 41, and a ventilation energy storage battery 43 is fixed to the top of the horn-shaped protective sleeve 41 by a support frame 42. A ventilation fan 44 is provided below the ventilation energy storage battery 43 and is electrically connected to the ventilation energy storage battery 43. The floating plate 3 is annular, and four solar panels 5 are distributed circumferentially on the floating plate 3. The solar panels 5 are electrically connected to the ventilation energy storage battery 43. The solar panels 5 convert solar energy into electrical energy and store it in the ventilation energy storage battery 43 to ensure the power supply of the ventilation fan 44. The support frame 42 connected to the horn-shaped protective sleeve 41 is used to fix the ventilation fan 44 to prevent the ventilation fan 44 from shaking during operation. At the same time, the shape of the horn-shaped protective sleeve 41 can prevent flowing sewage from splashing into the hollow body 1, thereby protecting the cathode plate 22. The float plate 3 provides buoyancy for the entire structure. Simultaneously, the float plate 3 can carry solar panels 5 to provide kinetic energy to the ventilation fan 44. The ventilation fan 44 rotates its blades, continuously circulating the air in the air cathode chamber. Because the hollow cylinder inserted into the sewage has a certain depth, the bottom air cathode may only come into contact with a small amount of oxygen. However, the continuous air exchange by the ventilation fan 44 ensures that all cathode plates 22 can undergo cathode reactions with sufficient oxygen. This improves the power output and coulombic efficiency of a single microbial fuel cell 2.

[0044] Example 2

[0045] The difference between this embodiment and Embodiment 1 is that the microbial fuel cells 2 in the same column are connected in parallel sequentially via connecting wires, such as... Figure 5 As shown.

[0046] Example 3

[0047] The difference between this embodiment and embodiment 1 is that: there are two hollow bodies 1, and the bottoms of the two hollow bodies 1 are connected by a connecting pipe 9. The ventilation fans 44 of the two hollow bodies 1 respectively carry in air and exhaust air, thereby improving the ventilation effect.

[0048] Example 4

[0049] like Figure 6-7 As shown, an energy storage system based on stacked microbial fuel cells includes a microbial power generation unit composed of several stacked microbial fuel cells. The several stacked microbial fuel cells are connected by a fixed node type 63 distributed circuit 6. The microbial power generation unit is set in the anoxic zone 8 of the sewage biological pond. The fixed node type 63 distributed circuit 6 is connected to an energy storage unit 7, which is an energy storage lithium battery.

[0050] The fixed node 63 type distributed circuit 6 includes a horizontal circuit section 61 and a vertical circuit section 62. The intersection of the horizontal circuit section 61 and the vertical circuit section 62 is the fixed node 63. Several stacked microbial fuel cells are distributed in a matrix or staggered manner at the fixed node 63. The spacing between adjacent fixed nodes 63 is 1.5-2 times the outer diameter of the floating plate 3.

[0051] Example 5

[0052] A working method based on the above energy storage system includes the following specific steps:

[0053] Step S1: Determine the dimensions of the fixed node 63 distributed circuit 6 based on the dimensions of the anoxic zone 8 and the floating plate 3 in the wastewater biological tank. The anoxic zone 8 of the wastewater biological tank is equally divided by the horizontal circuit section 61 and the vertical circuit section 62. At the fixed node 63, stacked microbial fuel cells can be arranged in a matrix or staggered manner according to the given requirements, such as... Figure 6-7 As shown, the arrow indicates the direction of sewage flow.

[0054] The height of hollow body 1 was determined based on the depth of the anoxic zone 8 in the wastewater biological pond, and a stacked microbial fuel cell was assembled. The airtightness of hollow body 1 was also determined.

[0055] Step S2: The assembled stacked microbial fuel cell is placed on the fixed node 63 of the fixed node 63 type distributed circuit 6 and inserted into the anoxic zone 8 of the sewage biological pond. The fixed node 63 type distributed circuit 6 is connected to the energy storage unit 7.

[0056] Step S3: The anoxic zone 8 of the wastewater biological tank begins operation. Wastewater slowly flows from one end to the other. When passing through the stacked microbial fuel cell, the microorganisms in the wastewater attach to the anode plate 21 and degrade the organic matter in the wastewater on the anode plate 21. The electrons generated by the reaction on the anode plate 21 are transported to the cathode plate 22 through the connecting wires. The protons generated by the reaction on the anode plate 21 are transported to the cathode plate 22 through the wastewater drainage pipe 24 and react with oxygen in the air on the cathode plate 22. The electrical energy generated by the reaction of the stacked microbial fuel cell is transported to the energy storage unit 7 through the fixed node 63 type distributed circuit 6.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A stacked microbial fuel cell for wastewater treatment, characterized in that: A stacked microbial fuel cell is inserted into the anoxic zone of a wastewater biological treatment pond. The stacked microbial fuel cell includes two hollow bodies with ventilation ports. Several interconnected microbial fuel cells are installed on the hollow bodies. Each microbial fuel cell includes an anode plate and a cathode plate. A float plate is installed at the ventilation port of each hollow body. Support legs are installed at the bottom of each hollow body. A ventilation mechanism is installed at the ventilation port of each hollow body. The ventilation mechanism includes a horn-shaped protective sleeve. A ventilation energy storage battery is fixed to the top of the horn-shaped protective sleeve by a support frame. A ventilation fan is installed below the ventilation energy storage battery and is electrically connected to the ventilation energy storage battery. The float plate is annular and has at least one solar panel installed on it. The solar panel is electrically connected to the ventilation energy storage battery. A ventilation pipe is connected to the bottom of the two hollow bodies. The ventilation fans of the two hollow bodies are used for air intake and exhaust, respectively. Several anode plates are evenly fixed to the outside of the hollow body by fasteners, and several cathode plates are arranged opposite to several anode plates and fixed to the inside of the hollow body by sewage drainage pipes. One end of the sewage drainage pipes is set in the through hole of the hollow body.

2. The stacked microbial fuel cell for wastewater treatment according to claim 1, characterized in that: The hollow body is a hollow cylinder or a hollow prism, and its height is less than the depth of the anoxic zone in the wastewater biological treatment pond.

3. An energy storage system for a stacked microbial fuel cell for wastewater treatment based on any one of claims 1-2, characterized in that: It includes a microbial power generation unit composed of several stacked microbial fuel cells, which are connected by a fixed node distributed circuit. The microbial power generation unit is set in the anoxic zone of the wastewater biological pond, and the fixed node distributed circuit is connected to an energy storage unit. The fixed-node distributed circuit includes a horizontal circuit section and a vertical circuit section. The intersection of the horizontal circuit section and the vertical circuit section is the fixed node. Several stacked microbial fuel cells are distributed in a matrix or cross arrangement at the fixed node.

4. An energy storage system according to claim 3, characterized in that: The spacing between adjacent fixed nodes is 1.5-2 times the outer diameter of the floating plate.

Images