Microbial fuel cell reaction device of anaerobic / aerobic membrane bioreactor

Abstract

The invention discloses a microbial fuel cell reaction device of a similar anaerobic / aerobic membrane bioreactor. The device comprises a water inlet system, a water outlet system, a microbial fuel cell reaction device main body and an electric energy data acquisition system, an anode anaerobic reaction chamber, a middle baffling area and a cathode aerobic reaction chamber are arranged inside the microbial fuel cell reaction device main body; the anode anaerobic reaction chamber adopts a plug flow type operation mode, and anaerobic sludge and a carbon brush are arranged in the anode anaerobic reaction chamber; the middle baffling region is used for isolating the anode anaerobic reaction chamber from the cathode aerobic reaction chamber through a left plate and a right plate respectively, and is used for replacing a semipermeable membrane in a traditional microbial fuel cell by filling cobblestones at the bottom; the cathode aerobic reaction chamber adopts a suspension-rotation biological cathode and is introduced into a hollow fiber membrane assembly, and the operation mode is a complete mixing mode. The device has the advantages of low cost, simple structure, easiness in expansion, high long-term operation stability, high electricity generation efficiency and high sewage treatment capacity.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment and relates to a device capable of efficiently treating sewage and recovering bioelectricity from sewage Background Art

[0002] A typical microbial fuel cell consists of an anode chamber and a cathode chamber, and the two compartments are usually separated by a membrane that allows proton exchange. Microorganisms in the anode chamber decompose organic matter through anaerobic respiration to produce protons and electrons. Protons pass through the semipermeable membrane into the cathode chamber, and electrons flow to the cathode electrode through an external circuit, where the electron acceptor is reduced at the cathode electrode terminal, and the movement of electrons in the external wire generates electricity. Microbial fuel cells have a wide range of application potential in the field of sewage treatment, and can produce clean and renewable bioelectricity while purifying sewage. In addition, compared with traditional activated sludge biological treatment technology, microbial fuel cells have low sludge production and low greenhouse gas emissions, which is very consistent with the current sustainable and energy-saving development needs in the field of water treatment. However, the commercial application of microbial fuel cells is still limited by many factors. First, the investment cost is high. The cost of components such as anode, cathode materials, and proton exchange membranes of microbial fuel cells is high, especially after the scale is expanded. Secondly, in sewage treatment, the long-term stability and life of microbial fuel cells are still not ideal, and how to maintain their long-term effective operation is an urgent problem to be solved. In addition, the current density of most microbial fuel cells is still low, and it is urgent to improve the efficiency of microbial electrochemical reactions and the electron conduction inside the battery. Finally, due to limitations in system design such as electrode layout and reactor structure, it is difficult to scale up microbial fuel cells. Summary of the invention

[0003] In view of the shortcomings of microbial fuel cells, such as high construction cost, difficulty in scale expansion, long-term operation stability and sewage treatment performance to be improved, the present invention provides a microbial fuel cell reaction device similar to an anaerobic / aerobic membrane bioreactor with low cost, simple structure, easy expansion, strong long-term operation stability, high power generation efficiency and strong sewage treatment capacity.

[0004] The objective of the present invention is achieved through the following technical solutions: A microbial fuel cell reaction device similar to an anaerobic / aerobic membrane bioreactor, comprising a water inlet system, a water outlet system, a microbial fuel cell reaction device body and an electric energy data acquisition system, wherein: The main body of the microbial fuel cell reaction device is provided with an anode anaerobic reaction chamber, an intermediate baffle area and a cathode aerobic reaction chamber in sequence; The anode anaerobic reaction chamber is provided with anaerobic sludge and carbon brushes; The middle baffle area is separated from the anode anaerobic reaction chamber and the cathode aerobic reaction chamber by a left plate and a right plate, respectively, and the bottom of the middle baffle area is filled with pebbles; The cathode aerobic reaction chamber is provided with aerobic sludge, a mechanical stirrer, a conductive slip ring, a titanium metal brush, a carbon felt block, a hollow fiber membrane assembly, an aeration pump, an aeration pipe and an aeration stone. The upper end of the titanium metal is connected to the mechanical stirrer and rotates therewith, and is connected to an external circuit through a conductive slip ring, and the lower end of the titanium metal is in intermittent contact with the carbon felt block; a hollow fiber membrane assembly is provided on one side of the cathode aerobic reaction chamber away from the anode anaerobic reaction chamber, and the aeration stone is located directly below the hollow fiber membrane assembly, and the aeration stone is connected to the aeration pump through the aeration pipe; The water inlet system comprises a water inlet bucket, a water inlet pump and a water inlet pipe. The water inlet bucket is arranged on one side of the anode anaerobic reaction chamber. The sewage in the water inlet bucket is pumped by the water inlet pump and flows into the anode anaerobic reaction chamber through the water inlet pipe. The water outlet system comprises a water outlet bucket, a water outlet pump and a water outlet pipe. The water outlet bucket is arranged on one side of the cathode aerobic reaction chamber. The treated water extracted by the water outlet pump from the hollow fiber membrane assembly of the cathode aerobic reaction chamber flows into the water outlet bucket through the water outlet pipe. The electric energy data acquisition system includes a wire, a resistor box, a data collector and a computer. The carbon brush is connected to the negative pole of the resistor box through the wire, and the conductive slip ring is connected to the positive pole of the resistor box through the wire. At the same time, the positive and negative poles of the resistor box are connected to the positive and negative poles of the data collector. The data collector captures the voltage information generated at both ends of the resistor box and transmits it to the computer for recording and storage.

[0005] Compared with the prior art, the present invention has the following advantages: 1. The reaction device designed by the present invention has low cost. The expensive proton exchange membrane is replaced by a baffle area filled with a small amount of pebbles, and a biological cathode is used to catalyze the cathode reduction reaction by microorganisms. No expensive metal catalysts or special cathode electrode materials are required, and there is no need to regularly replace the cathode electrolyte. In addition, the cathode aerobic reaction chamber of the device of the present invention uses environmentally friendly and relatively low-priced carbon felt, as well as titanium metal brushes that will not be lost during use. These designs reduce both construction costs and operating costs.

[0006] 2. The reaction device designed in the present invention has high sewage treatment performance. After the sewage enters the anode anaerobic reaction chamber and is treated with anaerobic sludge, it flows through the middle baffle area and directly enters the cathode aerobic reaction chamber to be further treated with aerobic sludge, thereby realizing anaerobic-aerobic two-stage treatment, which can efficiently remove organic matter, ammonia nitrogen and other pollutants in the sewage. In addition, through the special layout of the carbon brushes in the anode anaerobic reaction chamber, the water flow direction of the anode anaerobic area is optimized, which helps the feed to fully contact the carbon brushes, thereby improving the anode pollutant degradation and power generation efficiency. The introduction of an ultrafiltration membrane assembly in the cathode aerobic chamber can further improve the effluent water quality while eliminating the secondary sedimentation tank and preventing the suspended carbon felt from being lost with the sludge.

[0007] 3. The reaction device designed by the present invention has a simple structure and is easy to expand. The overall structure of the novel microbial fuel cell reaction device designed by the present invention is similar to that of an anaerobic / aerobic membrane bioreactor. It does not have a complex structure that is difficult to scale up or whose cost will rise sharply after scale-up. In addition, the anaerobic / aerobic membrane bioreactor is a mature technology that has been actually applied in the field of sewage treatment. Therefore, the microbial fuel cell reaction device similar to an anaerobic / aerobic membrane bioreactor designed by the present invention has the potential to be built into medium- and large-scale integrated equipment.

[0008] 4. The suspended-rotating biocathode designed in the present invention enhances the power generation efficiency and stability of the microbial fuel cell, improves its sewage treatment effect, and helps alleviate membrane pollution. The movement of the sludge and the suspended carbon felt block with the rotating titanium metal brush enhances the transfer effect of organic matter and oxygen and other substances between the microorganisms and the surface of the carbon felt block in the cathode aerobic reaction chamber, thereby increasing the cathode reduction reaction rate and the power generation efficiency of the device, maintaining the long-term stability of the cathode potential and the power generation of the device, and reducing the aeration demand. The movement of the sludge and the suspended carbon felt block can hinder the formation of the filter cake layer on the membrane surface through hydraulic shearing, thereby reducing membrane pollution. In addition, since the carbon felt block is fully mixed with the sludge, the microorganisms adhere to the carbon felt surface, which can promote direct interspecies electron transfer, increase the activity of microorganisms, and accelerate the degradation of pollutants. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A front view of a microbial fuel cell reaction device similar to an anaerobic / aerobic membrane bioreactor; Figure 2 A top view of the main part of a microbial fuel cell reaction device similar to an anaerobic / aerobic membrane bioreactor; Figure 3 It is a perspective view of the water flow path in the middle baffle area; Figure 4 It is a stereoscopic image of a titanium brush; Figure 5 It is a top view of the titanium brush; In the figure: 1-anode anaerobic reaction chamber, 2-middle baffle area, 3-cathode aerobic reaction chamber, 4-water inlet bucket, 5-water inlet pipe, 6-water inlet pump, 7-water outlet pipe, 8-water outlet pump, 9-water outlet bucket, 10-carbon brush, 11-pebbles, 12-titanium metal brush, 13-carbon felt block, 14-hollow fiber membrane assembly, 15-aeration pump, 16-aeration pipe, 17-aeration stone, 18-mechanical agitator, 19-conductive slip ring, 20-wire, 21-resistance box, 22-data collector, 23-computer. DETAILED DESCRIPTION

[0010] The technical solution of the present invention is further described below in conjunction with the accompanying drawings, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0011] The present invention provides a microbial fuel cell reaction device similar to an anaerobic / aerobic membrane bioreactor, such as Figure 1 and Figure 2 As shown, the device includes a water inlet system, a water outlet system, a microbial fuel cell reaction device body and an electric energy data acquisition system, wherein: The water inlet system is composed of a water inlet bucket 4 , a water inlet pump 6 and a water inlet pipe 5 .

[0012] The water outlet system is composed of a water outlet bucket 9 , a water outlet pump 8 and a water outlet pipe 7 .

[0013] The main body of the microbial fuel cell reaction device is provided with an anode anaerobic reaction chamber 1, a middle baffle area 2 and a cathode aerobic reaction chamber 3 in sequence.

[0014] The anode anaerobic reaction chamber 1 adopts a plug flow operation mode, and is provided with anaerobic sludge and six carbon brushes 10 arranged in a certain pattern inside, and is always in a closed state during operation. The carbon brushes 10 are used as anode electrodes, wherein every two carbon brushes 10 are closely arranged to form a row, and there are three rows in total. Figure 2 The parallel staggered arrangement shown improves the water flow direction and promotes full contact between sewage, carbon brushes 10 and anaerobic sludge.

[0015] The middle baffle area 2 is separated from the anode anaerobic reaction chamber 1 and the cathode aerobic reaction chamber 3 by the left plate and the right plate, respectively. The height of the left plate of the middle baffle area 2 is equal to the total height of the anode anaerobic reaction chamber 1. A hole is opened in the upper part of the left plate, and the opening style is rectangular, so that water can flow into the middle baffle area 2. The top of the right plate of the middle baffle area 2 is flush with the upper part of the cathode aerobic reaction chamber 3, and the lower part is not connected to the bottom plate of the cathode aerobic reaction chamber 3, so that water can flow out to the cathode aerobic reaction chamber 3. In addition, a small amount of pebbles 11 are filled at the bottom of the middle baffle area 2. The middle baffle area 2 filled with pebbles 11 is used to replace the function of the semipermeable membrane in the traditional microbial fuel cell, which can not only ensure that the effluent of the anode anaerobic reaction chamber 1 can flow directly into the cathode aerobic reaction chamber 3, but also prevent the oxygen in the cathode aerobic reaction chamber 3 from entering the anode anaerobic reaction chamber 1 and destroying its anaerobic environment.

[0016] The cathode aerobic reaction chamber 3 adopts a suspended-rotating biological cathode and introduces a hollow fiber membrane assembly 14, and the operation mode is a complete mixing type. The cathode aerobic reaction chamber 3 is provided with aerobic sludge, a mechanical stirrer 18, a conductive slip ring 19, a titanium metal brush 12, a carbon felt block 13, a hollow fiber membrane assembly 14, an aeration pump 15, an aeration pipe 16 and an aeration stone 17. The carbon felt block 13 is completely mixed with the aerobic sludge, similar to a dispersed biological filler, and they move in the reaction chamber with the rotation of the titanium metal brush 12. The titanium metal brush 12 serves as a current collector, and its upper end is connected to the stirrer 18 and rotates therewith, and is connected to the external circuit through a conductive slip ring 19, and its lower end is intermittently in contact with the carbon felt block 13 suspended in the water below the liquid surface. The titanium metal brush 12 and the carbon felt block 13 together constitute the cathode electrode. In addition, a hollow fiber membrane assembly 14 is arranged on the side of the cathode aerobic reaction chamber 3 away from the anode anaerobic reaction chamber 1 to replace the secondary sedimentation tank, and the filtered water extracted from the hollow fiber membrane assembly 14 is used as the final effluent of the reaction device designed by the present invention. The introduction of the hollow fiber membrane assembly 14 simplifies the device structure, reduces the loss of the carbon felt block 13 with the sludge, and is conducive to improving the effluent water quality. In addition, the aeration pump 15 evenly transports air to the bottom of the hollow fiber membrane assembly 14 through the aeration pipe 16 and the aeration stone 17, which provides oxygen to the cathode aerobic reaction chamber 3 while alleviating the membrane pollution on the hollow fiber membrane assembly 14.

[0017] The water inlet system is composed of a water inlet bucket 4 , a water inlet pump 6 and a water inlet pipe 5 . The water inlet bucket 4 is arranged on one side of the anode anaerobic reaction chamber 1 . The sewage in the water inlet bucket 4 is pumped by the water inlet pump 6 and flows into the anode anaerobic reaction chamber 1 through the water inlet pipe 5 .

[0018] The water outlet system is composed of a water outlet bucket 9, a water outlet pump 8 and a water outlet pipe 7. The water outlet bucket 9 is arranged on one side of the cathode aerobic reaction chamber 3. The treated water extracted by the water outlet pump 8 from the hollow fiber membrane assembly 14 of the cathode aerobic reaction chamber flows into the water outlet bucket 9 through the water outlet pipe 7.

[0019] The electric energy data acquisition system is composed of a wire 20, a resistor box 21, a data collector 22 and a computer 23. The carbon brush 10 is connected to the negative electrode of the resistor box 21 through the wire 20, and the conductive slip ring 19 is connected to the positive electrode of the resistor box 21 through the wire 20. At the same time, the positive and negative electrodes of the resistor box 21 are connected to the positive and negative electrodes of the data collector 22. The data collector 22 captures the voltage information generated at both ends of the resistor box 21 and transmits it to the computer 23 for recording and storage.

[0020] The specific operation process is as follows: the sewage in the water inlet bucket 4 flows into the anode anaerobic reaction chamber 1 from the lower right corner of the left wall of the anode anaerobic reaction chamber 1 through the water inlet pump 6 and the water inlet pipe 5. Under the special layout of the six carbon brushes 10, the sewage flows along the longer path ( Figure 2 ) moves to the middle baffle area 2, and part of the pollutants in the sewage are degraded by the anaerobic sludge, and then flows through the middle baffle area 2 and the pebbles 11 into the cathode aerobic reaction chamber 3. In the cathode aerobic reaction chamber 3, the remaining pollutants in the sewage are further degraded by the aerobic sludge, and then the hollow fiber membrane assembly 14 is used to separate the mud and water, and finally the deeply purified effluent is obtained. While the anode anaerobic reaction chamber 1 and the cathode aerobic reaction chamber 2 realize the two-stage treatment of sewage, the anaerobic microorganisms in the anode anaerobic reaction chamber 1 use the pollutants to generate electrons, and the electrons are finally transmitted from the carbon brush 10 to the carbon felt block 13 in the cathode aerobic reaction chamber 3 through the wire 20, the resistor box 21, the conductive slip ring 19 and the titanium metal brush 20. At the same time, the aerobic microorganisms in the cathode aerobic reaction chamber 3 catalyze the occurrence of the cathode reduction reaction, promote the electron acceptor (such as oxygen and nitrate, etc.) to accept the electrons on the carbon felt block 13 and be reduced, and then form a potential difference between the anode and the cathode, and generate a voltage at both ends of the resistor box 21. The voltage signal at both ends of the resistor box 21 is detected by the data collector 22 and converted into voltage data and stored in the computer 23. Through the above process, the microbial fuel cell reaction device similar to the anaerobic / aerobic membrane bioreactor designed by the present invention can ultimately generate bioelectricity stably and efficiently remove pollutants in sewage.

[0021] In the present invention, the titanium metal brush 12 is welded by a titanium rod and five titanium plates, and the welding angles of the five titanium plates are: the angle between the upper plate and the lower plate is 0°, the angle of the middle plate is 90°, and the angles of the other two plates are 45° with the upper plate in turn ( Figure 4 , Figure 5 ).

[0022] In the present invention, the filling rate of the carbon felt block 13 in the cathode aerobic reaction chamber 3 is about 40%.

[0023] In the present invention, the filling height of the pebbles 11 is approximately one quarter to one third of the total height of the middle baffle area 2 .

[0024] In the present invention, the main body of the microbial fuel cell reaction device is made of organic glass, 300 mm long, 100 mm wide and 100 mm high. After the carbon brush 10, pebbles 11, titanium metal brush 12, carbon felt block 13, hollow membrane assembly 14 and aeration stone 17 are filled, the effective volume of the reaction device is about 2.2L.

Claims

1. A microbial fuel cell reaction device similar to an anaerobic / aerobic membrane bioreactor, characterized in that The device comprises a water inlet system, a water outlet system, a microbial fuel cell reaction device body and an electric energy data acquisition system, wherein: The water inlet system includes a water inlet bucket, a water inlet pump and a water inlet pipe; The water outlet system includes a water outlet bucket, a water outlet pump and a water outlet pipe; The main body of the microbial fuel cell reaction device is provided with an anode anaerobic reaction chamber, an intermediate baffle area and a cathode aerobic reaction chamber in sequence; The anode anaerobic reaction chamber is provided with anaerobic sludge and carbon brushes; The middle baffle area is separated from the anode anaerobic reaction chamber and the cathode aerobic reaction chamber by a left plate and a right plate, respectively, and the bottom of the middle baffle area is filled with pebbles; The cathode aerobic reaction chamber is provided with aerobic sludge, a mechanical stirrer, a conductive slip ring, a titanium metal brush, a carbon felt block, a hollow fiber membrane assembly, an aeration pump, an aeration pipe and an aeration stone. The upper end of the titanium metal is connected to the mechanical stirrer and rotates therewith, and is connected to an external circuit through a conductive slip ring, and the lower end of the titanium metal is in intermittent contact with the carbon felt block; a hollow fiber membrane assembly is provided on one side of the cathode aerobic reaction chamber away from the anode anaerobic reaction chamber, and the aeration stone is located directly below the hollow fiber membrane assembly, and the aeration stone is connected to the aeration pump through the aeration pipe; The water inlet bucket is arranged at one side of the anode anaerobic reaction chamber, and the sewage in the water inlet bucket is pumped by the water inlet pump and flows into the anode anaerobic reaction chamber through the water inlet pipe; The water outlet bucket is arranged at one side of the cathode aerobic reaction chamber, and the treated water extracted by the water outlet pump from the hollow fiber membrane assembly of the cathode aerobic reaction chamber flows into the water outlet bucket through the water outlet pipe; The electric energy data acquisition system includes a wire, a resistor box, a data collector and a computer. The carbon brush is connected to the negative pole of the resistor box through the wire, and the conductive slip ring is connected to the positive pole of the resistor box through the wire. At the same time, the positive and negative poles of the resistor box are connected to the positive and negative poles of the data collector. The data collector captures the voltage information generated at both ends of the resistor box and transmits it to the computer for recording and storage.

2. The microbial fuel cell reaction device of the anaerobic / aerobic membrane bioreactor according to claim 1 is characterized in that The number of the carbon brushes is 6, wherein every two carbon brushes are closely arranged in a row, and there are three rows in total, and the carbon brushes in the three rows are arranged in parallel and staggered.

3. The microbial fuel cell reaction device of the anaerobic / aerobic membrane bioreactor according to claim 1 is characterized in that The height of the left plate of the middle baffle area is equal to the total height of the anode anaerobic reaction chamber, and a hole is opened on the upper part of the left plate to supply water to flow into the middle baffle area.

4. The microbial fuel cell reaction device of the anaerobic / aerobic membrane bioreactor according to claim 3 is characterized in that The opening is in the shape of a rectangle.

5. The microbial fuel cell reaction device of the anaerobic / aerobic membrane bioreactor according to claim 1 is characterized in that The top of the right plate of the middle baffle area is flush with the upper part of the cathode aerobic reaction chamber, and the lower part is not connected to the bottom plate of the cathode aerobic reaction chamber, so that the water flow flows out to the cathode aerobic reaction chamber.

6. The microbial fuel cell reaction device of the anaerobic / aerobic membrane bioreactor according to claim 1, characterized in that The titanium metal brush is welded by a titanium rod and five titanium plates, the welding angles of the five titanium plates are as follows: the angle between the upper plate and the lower plate is 0°, the angle of the middle plate is 90°, and the angles of the other two plates are 45° with the upper plate in turn.

7. The microbial fuel cell reaction device of the anaerobic / aerobic membrane bioreactor according to claim 1 is characterized in that The filling rate of the carbon felt block in the cathode aerobic reaction chamber is 40%.

8. The microbial fuel cell reaction device of the anaerobic / aerobic membrane bioreactor according to claim 1, characterized in that The filling height of the pebbles is one quarter to one third of the total height of the middle baffle area.

9. The microbial fuel cell reaction device of the anaerobic / aerobic membrane bioreactor according to claim 1, characterized in that The main body of the microbial fuel cell reaction device is made of organic glass.

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