An apparatus for coupling microbial fuel cell to electrically drive anaerobic ammonia oxidation-denitrification

Abstract

The application discloses a device for coupling electrically-driven anaerobic ammonia oxidation-denitrification by using a microbial fuel cell, comprising a microbial fuel cell and a microbial electrochemical reactor; wherein the microbial fuel cell is single-chambered, the anode is an anaerobic sludge membrane-hung carbon brush, and the cathode is carbon cloth; the working electrode of the microbial electrochemical reactor is a carbon brush, anaerobic ammonia oxidation flocculent sludge is inoculated into the reactor under anaerobic conditions, and after stable biofilm is formed, the device is operated under anoxic conditions. When the device is used for degrading organic matters by using the microbial fuel cell, the generated electric energy is used for driving the anaerobic ammonia oxidation process in the microbial electrochemical reactor to couple denitrification for removing nitrogen elements in wastewater, so that no external electric energy is consumed, and recyclable electric energy can be generated, and no secondary pollution is caused, so that the device is an environment-friendly wastewater treatment structure which is capable of removing nitrogen and carbon.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater biological treatment, in particular to a device for coupling microbial fuel cell and electrically driven anaerobic ammonia oxidation-denitrification. BACKGROUND

[0002] In the field of sewage treatment, microbial fuel cells can convert organic matter in wastewater into electrical energy. Compared with other existing organic matter energy production technologies, microbial fuel cells not only have high energy conversion efficiency and adaptability, but also have wide application prospects.

[0003] At present, in the process of upgrading and reconstruction of municipal wastewater treatment, the removal of total nitrogen in the system is a key problem to be solved. Anaerobic ammonia oxidation process and its coupling process have been paid more and more attention and applied in the field of wastewater denitrification. However, since the nitrogen in wastewater mainly exists in the form of ammonia nitrogen and nitrate nitrogen, the anaerobic ammonia oxidation process usually needs to rely on the nitration and short-term denitrification process to provide nitrite nitrogen, forming a variety of coupling processes such as nitration-anaerobic ammonia oxidation, short-term denitrification-anaerobic ammonia oxidation, nitration-anaerobic ammonia oxidation-denitrification. The above processes have been successfully practiced in the treatment of high-concentration ammonia nitrogen wastewater with low carbon-nitrogen ratio, but there are still many problems in the process of municipal sewage treatment, such as unstable operation, high energy consumption, and high total nitrogen content in effluent. SUMMARY

[0004] The purpose of the present application is to provide a device for coupling microbial fuel cell and electrically driven anaerobic ammonia oxidation-denitrification, which utilizes the electrical energy generated by microbial fuel cell MFC to degrade organic matter to drive microbial electrochemical reactor MEC, and simultaneously utilizes electrically driven anaerobic ammonia oxidation-denitrification technology to remove nitrogen elements in wastewater, thereby producing electrical energy that can be recycled.

[0005] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows: a device for coupling microbial fuel cell and electrically driven anaerobic ammonia oxidation-denitrification, comprising a microbial fuel cell and a microbial electrochemical reactor; wherein the microbial fuel cell comprises a first carbon brush electrode, a carbon cloth electrode, and a first water outlet; the microbial electrochemical reactor comprises a second carbon brush electrode, a platinum mesh electrode, and a second water inlet, the second water inlet is connected with the first water outlet through a water inlet pipeline, the second carbon brush electrode is coupled and connected with the carbon cloth electrode, and the platinum mesh electrode and the first carbon brush electrode form a loop through a series resistor.

[0006] Further, the first carbon brush electrode is located in the interior of the microbial fuel cell, the carbon cloth electrode is located on the side of the microbial fuel cell, the first water outlet is located at the upper part of the microbial fuel cell, and the first water inlet is located at the lower part of the microbial fuel cell.

[0007] Further, the microbial fuel cell further comprises a first rotor and a first sampling port, wherein the first rotor is located inside the microbial fuel cell and arranged below the first carbon brush electrode, and the first sampling port is located at the top of the microbial fuel cell.

[0008] Further, the second carbon brush electrode and the platinum mesh electrode are located inside the microbial electrochemical reactor; the second water outlet is located at the upper part of the microbial electrochemical reactor, and the second water inlet is located at the lower part of the microbial electrochemical reactor.

[0009] Further, the microbial electrochemical reactor further comprises an Ag / AgCl reference electrode, a second rotor, a data collector and a second sampling port, wherein the Ag / AgCl reference electrode and the second rotor are located inside the microbial electrochemical reactor, and the second rotor is arranged below the second carbon brush electrode, one side of the second carbon brush electrode is the platinum mesh electrode, and the other side is the Ag / AgCl reference electrode, and the Ag / AgCl reference electrode is connected to the data collector; the data collector and the second sampling port are located at the top of the microbial electrochemical reactor.

[0010] Further, the microbial fuel cell is an air cathode microbial fuel cell, the effective volume can be 350 mL, the anode material is a carbon brush, the cathode material is a carbon cloth, and the inoculated sludge is anaerobic sludge; the first carbon brush electrode can provide attachment points for microorganisms to form stable biofilms due to its large specific surface area.

[0011] Further, in the microbial fuel cell, the initial COD concentration of the start-up substrate is 400-800 mg / L, and the pH value of the start-up substrate is 7.5±0.2, and the start-up substrate comprises glucose, potassium chloride, ammonium chloride, phosphate buffer, trace minerals and vitamins, wherein the COD of glucose is 400-800 mg / L, the concentration of potassium chloride is 0.11-0.15 g / L, the concentration of ammonium chloride is 0.25-0.35 g / L, the concentration of trace minerals is 11.5-13.5 mM / L, and the concentration of vitamins is 4-6 mM / L.

[0012] Further, in the microbial electrochemical reactor, the effective volume of the microbial electrochemical reactor can be 500 mL, the working electrode is a carbon brush, the counter electrode is a platinum mesh, the distance between the two electrodes is 0.8-1.2 cm, the reference electrode is Ag / AgCl, and the inoculated sludge is anaerobic ammonia oxidation flocculent sludge; the second carbon brush electrode can provide attachment points for microorganisms to form stable biofilms due to its large specific surface area.

[0013] Further, in the microbial electrochemical reactor, the initial ammonia nitrogen concentration of the start-up substrate is 35-70 mg / L, and the pH value of the start-up substrate is 7.0±0.2.

[0014] The present application can achieve the following technical effects due to the above technical solutions:

[0015] 1. The microbial fuel cell can complete more than 90% of the carbon removal process and provide stable voltage output for the microbial electrochemical reactor, which is used to maintain the electrically driven anaerobic ammonia oxidation process.

[0016] 2. The electrically driven anaerobic ammonia oxidation-denitrification process can directly convert ammonia nitrogen into nitrogen gas and produce a small amount of nitrate nitrogen, effectively reducing the total nitrogen emission of the effluent.

[0017] 3. High-efficiency denitrification and carbon removal can be achieved under low energy consumption conditions, and electrical energy can also be produced for recycling. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural schematic diagram of a microbial fuel cell coupled with an electrically driven anaerobic ammonia oxidation-denitrification device.

[0019] In the figure, 1 is a microbial fuel cell MFC, 2 is a first carbon brush electrode, 3 is a carbon cloth electrode, 4 is a first rotor, 5 is a first water inlet, 6 is a first water outlet, 7 is a first sampling port, 8 is a resistor, 9 is a microbial electrochemical reactor MEC, 10 is a second carbon brush electrode, 11 is a platinum mesh electrode, 12 is an Ag / AgCl reference electrode, 13 is a second rotor, 14 is a data acquisition device, 15 is a second sampling port, 16 is a second water outlet, 17 is a second water inlet, and 18 is a water inlet pipeline. DETAILED DESCRIPTION

[0020] The embodiments of the present application are implemented on the premise of the technical solutions of the present application, and detailed implementation methods and specific operation processes are given, but the protection scope of the present application is not limited to the following embodiments.

[0021] Example 1

[0022] As Figure 1As shown, the embodiment provides a device for coupling electrically driven anaerobic ammonia oxidation-denitrification of an anaerobic ammonia oxidation-denitrification device, which comprises a first water outlet 6 of a microbial fuel cell MFC1 and a second water inlet 17 of a microbial electrochemical reactor MEC9 connected by a water inlet pipeline 18, a carbon cloth electrode 3 and a second carbon brush electrode 10 coupled and connected, and a first carbon brush electrode 2 and a platinum mesh electrode 11 forming a loop through a series resistor (preferably 10Ω) 8. The sewage first enters the microbial fuel cell MFC1 through the first water inlet 5, is mixed uniformly with the sludge by the first rotor 4, and the first carbon brush electrode 2 provides an attachment point for the sludge to react. Sampling is performed from the first sampling port 7 during the reaction period, and the water is discharged from the first water outlet 6 after the reaction period. Then the sewage from the first water outlet 6 of the microbial fuel cell MFC1 enters the second water inlet 17 through the water inlet pipeline 18 and then flows into the microbial electrochemical reactor MEC9, and the second carbon brush electrode 10 provides an attachment point for the sludge to react. The microbial electrochemical reactor MEC9 samples through the second sampling port 15, and the water is discharged through the second water outlet 16 after the reaction period. The data collector 14 collects the potentials of the platinum mesh electrode 11, the second carbon brush electrode 10, the carbon cloth electrode 3, and the first carbon brush electrode 2, respectively. The ammonia nitrogen concentration of the influent can be 35 mg / L, and the COD concentration is 800 mg / L. The COD removal rate of the microbial fuel cell MFC1 is 96.3%, the ammonia nitrogen removal rate is 15.7%, and the maximum open circuit voltage is 0.566 V. After the effluent of the microbial fuel cell MFC1 is pumped into the microbial electrochemical reactor MEC9, the ammonia nitrogen removal rate is about 85.5%, the total nitrogen removal rate is 76.8%, and the maximum current in the loop is about 0.06 mA.

[0023] Example 2

[0024] The difference between example 1 and example 2 is that the ammonia nitrogen and COD concentrations of the influent are different, the ammonia nitrogen influent concentration is 70 mg / L, and the COD influent concentration is 400 mg / L. After the microbial fuel cell MFC1 and the microbial electrochemical reactor MEC9 are connected and coupled, the microbial fuel cell MFC1 supplies power to the microbial electrochemical reactor MEC9. The ammonia nitrogen removal rate of the microbial fuel cell MFC1 is about 13.2%, and the COD removal efficiency is 82.5%. After the effluent is pumped into the microbial electrochemical reactor MEC9, the ammonia nitrogen removal rate can reach 76.3%, and the maximum current in the loop can be about 0.08 mA.

[0025] The present application can degrade organic matter by microbial fuel cells, and the generated electric energy can drive the anaerobic ammonia oxidation process in the microbial electrochemical reactor to couple the denitrification of wastewater to remove nitrogen elements. Not only does it not consume external electric energy, but it also produces recyclable electric energy and does not cause secondary pollution. It is an environmentally friendly wastewater treatment structure with denitrification and carbon removal.

[0026] The foregoing description of specific exemplary embodiments of the application has been presented for the purposes of illustration and description. It is not intended to be a limitation on the broad concepts of the application. Obviously, many modifications and variations of the specific exemplary embodiments described herein are possible in light of this disclosure, and it is intended that the scope of the application be limited only by the claims appended hereto and their equivalents. Examples of selected embodiments were chosen and described in order to best explain the principles of the application and its practical application to thereby enable others skilled in the art to best utilize the application. The application is intended to cover any adaptations or variations of the specific embodiments described herein.

Claims

1. A device for coupling microbial fuel cell to electrically drive anaerobic ammonia oxidation-denitrification, characterized in that, The application relates to a microbial fuel cell (1) and a microbial electrochemical reactor (9); wherein the microbial fuel cell (1) comprises a first carbon brush electrode (2), a carbon cloth electrode (3) and a first water outlet (6); the microbial electrochemical reactor (9) comprises a second carbon brush electrode (10), a platinum mesh electrode (11) and a second water inlet (17); the second water inlet (17) is connected with the first water outlet (6) through a water inlet pipeline (18); the second carbon brush electrode (10) is coupled with the carbon cloth electrode (3); the platinum mesh electrode (11) and the first carbon brush electrode (2) form a loop through a series resistor (8); The second carbon brush electrode (10) and the platinum mesh electrode (11) are located in the interior of the microbial electrochemical reactor (9); a second water outlet (16) is located at the upper portion of the microbial electrochemical reactor (9), and the second water inlet (17) is located at the lower portion of the microbial electrochemical reactor (9); The microbial electrochemical reactor (9) further comprises an Ag / AgCl reference electrode (12), a second rotor (13), a data collector (14) and a second sampling port (15); wherein the Ag / AgCl reference electrode (12) and the second rotor (13) are located in the interior of the microbial electrochemical reactor (9), and the second rotor (13) is arranged below the second carbon brush electrode (10); one side of the second carbon brush electrode (10) is the platinum mesh electrode (11), and the other side is the Ag / AgCl reference electrode (12); the Ag / AgCl reference electrode (12) is connected with the data collector (14); the data collector (14) and the second sampling port (15) are located at the top of the microbial electrochemical reactor (9); The microbial fuel cell (1) is an air cathode microbial fuel cell; the anode material is a carbon brush; the cathode material is carbon cloth; and the inoculated sludge is anaerobic sludge; the first carbon brush electrode (2) provides an attachment point for microorganisms to form a biofilm; In the microbial fuel cell (1), the initial concentration of the starting substrate is 400-800 mg / L, and the pH value of the starting substrate is 7.5+ / -0.2; the starting substrate comprises glucose, potassium chloride, ammonium chloride, phosphate buffer, trace minerals and vitamins; the COD of the glucose is 400-800 mg / L; the concentration of the potassium chloride is 0.11-0.15 g / L; the concentration of the ammonium chloride is 0.25-0.35 g / L; the concentration of the trace minerals is 11.5-13.5 mM / L; and the concentration of the vitamins is 4-6 mM / L; The first carbon brush electrode (2) is located in the interior of the microbial fuel cell (1), and the carbon cloth electrode (3) is located at the side of the microbial fuel cell (1); the first water outlet (6) is located at the upper portion of the microbial fuel cell (1), and the first water inlet (5) is located at the lower portion of the microbial fuel cell (1). The microbial fuel cell (1) further comprises a first rotor (4) and a first sampling port (7), wherein the first rotor (4) is located inside the microbial fuel cell (1) and is arranged below the first carbon brush electrode (2), and the first sampling port (7) is located at the top of the microbial fuel cell (1).

2. The apparatus of claim 1, wherein the microbial fuel cell is coupled to the electrically driven ANAMMOX-denitrification device. In the microbial electrochemical reactor (9), the working electrode is a carbon brush, the counter electrode is a platinum mesh, the distance between the two electrodes is 0.8-1.2 cm, the reference electrode is Ag / AgCl, and the inoculated sludge is anaerobic ammonia oxidation flocculent sludge; the second carbon brush electrode (10) provides an attachment point for microorganisms to form a stable biofilm.

3. The apparatus for microbial fuel cell coupled with electrically driven anaerobic ammonia oxidation-denitrification according to claim 1, characterized in that, In the microbial electrochemical reactor (9), the initial concentration of ammonia nitrogen in the starting substrate is 35-70 mg / L, and the pH value of the starting substrate is 7.0±0.2.

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