A method for improving the denitrification rate of electroactive anaerobic ammonium oxidation

Abstract

The present invention discloses a method for improving the denitrification rate of electroactive anaerobic ammonium oxidation. Based on the different electron transfer efficiencies of anaerobic ammonium oxidizing bacteria for different electron acceptors (nitrite nitrogen, electrode), the present invention studies the regulatory effect of a small amount of nitrite nitrogen electron acceptor on the growth metabolism and denitrification rate of anaerobic ammonium oxidizing bacteria in an electrochemical system, constructs a method for regulating the addition amount of nitrite nitrogen to improve the denitrification rate of the anode anaerobic ammonium oxidation in the microbial electrochemical system, and realizes the improvement of the denitrification performance of the anode anaerobic ammonium oxidation in the microbial electrochemical system. The method of the present invention is applied to the treatment of ammonia nitrogen-containing wastewater, has low operating costs, is economical and long-lasting, and has wide application value in sewage treatment and water environment protection.

Description

Technical Field

[0001] The invention relates to an anaerobic ammonium oxidation process, in particular to a method for improving the denitrification rate of electroactive anaerobic ammonium oxidation. Background Art

[0002] Ammonia nitrogen (NH4 + -N) is an important nitrogen pollutant in my country's water bodies. Excessive ammonia nitrogen discharged into natural water bodies will have a great impact on the environment and human health. The removal of ammonia nitrogen has always been one of the main tasks of water environment protection in my country. The nitrification-denitrification process requires a lot of energy to provide oxygen in the nitrification stage, and the denitrification stage requires additional organic carbon sources such as methanol, which imposes a large economic burden on wastewater treatment plants. Compared with the nitrification-denitrification biological denitrification process, the anaerobic ammonium oxidation (Anammox) process is a new autotrophic denitrification process that does not require external carbon sources and aeration.

[0003] The traditional anaerobic ammonium oxidation process is to use ammonia nitrogen (NH4 + -N) and nitrite nitrogen (NO2 - -N) as substrate, producing a small amount of nitrate nitrogen (NO3 - -N). It is difficult to completely remove the total nitrogen in the effluent, and secondary treatment is required. The nitrogen in the sewage is mainly ammonia nitrogen (NH4 + -N) exists in the form of anaerobic ammonium oxidation, so the traditional anaerobic ammonium oxidation process is usually combined with a partial nitrite process. By controlling the conditions, ammonia oxidizing bacteria (AOB) convert NH4 + -N is oxidized to NO2 - -N, preventing nitrite oxidizing bacteria (NOB) from further converting NO2 - -N is oxidized to NO3 - -N, partial nitrite can be achieved. Then, anaerobic ammonium oxidizing bacteria will convert NH4 + -N and NO2 - -N is reduced to nitrogen (N2) and escapes into the aqueous phase. The integrated partial nitritation-anaerobic ammonium oxidation process still requires a certain amount of energy to provide oxygen for the partial nitritation process. Furthermore, since AOB and NOB exist in similar environments and typically coexist, the presence of NOB is unavoidable in integrated processes, making complete control of NOB difficult to achieve.

[0004] Initially, anaerobic ammonium oxidizing bacteria were thought to be able to + -N is an electron donor, NO2 --N or nitric oxide (NO) as electron acceptor. More than a decade ago, preliminary experiments showed that anaerobic ammonium oxidizing bacteria can couple the oxidation of formate with the reduction of insoluble extracellular electron acceptors (such as Fe(III) or Mn(IV) oxides). However, the activity of extracellular electron transfer (EET) and the molecular mechanism of this coupling reaction remain unknown. In recent years, studies have found that anaerobic ammonium oxidizing bacteria have the ability to transfer extracellular electrons to insoluble extracellular electron acceptors. This has proposed a new degradation pathway based on NH4 + -N is the electron donor, the anode of the microbial electrolysis cell (MEC) is the electron acceptor, NH4 + -N is oxidized to N2 through hydroxylamine (NH2OH) as an intermediate. Anaerobic ammonium oxidizing bacteria are combined with microbial electrolysis cells (MECs). Anaerobic ammonium oxidation at the anode of the microbial electrolysis cell relies on extracellular electron transfer to convert NH4 + -N is completely oxidized to N2 without NO2 - -N and NO3 - -N accumulation. In the oxidation process of ammonia nitrogen, hydrogen ions and electrons are generated. Under the action of the external potential, the electrons are transferred to the cathode through the external circuit. The hydrogen ions are reduced to hydrogen at the cathode, and the hydrogen can be recovered as energy. In this process, no external carbon source and aeration are required, and there is no NO3 - -N production. This process greatly reduces the economic burden and does not require secondary treatment of NO3 - -N. However, the electron transfer efficiency of the anaerobic ammonium oxidation process that uses electrodes as electron acceptors and relies on extracellular electron transfer is lower than that of the traditional anaerobic ammonium oxidation process that uses nitrite nitrogen as electron acceptor. Therefore, this process has the problem of low denitrification rate.

[0005] Based on the different electron transfer efficiencies of anaerobic ammonium oxidizing bacteria for different electron acceptors (nitrite nitrogen, electrode), the present invention studies the regulatory effect of a small amount of nitrite nitrogen electron acceptor on the growth metabolism and denitrification rate of anaerobic ammonium oxidizing bacteria in an electrochemical system, constructs a method for regulating the dosage of nitrite nitrogen to increase the anode anaerobic ammonium oxidation denitrification rate in a microbial electrochemical system, achieves the improvement of the anode anaerobic ammonium oxidation denitrification performance in the microbial electrochemical system, and improves the problem of poor denitrification effect of electroactive anaerobic ammonium oxidation.

[0006] Ni Shouqing, Zhou Jing, Wang Zhibin, et al. A method for treating ammonia-nitrogen wastewater using extracellular electron transfer anaerobic ammonium oxidation [P]. Shandong Province: CN202310478579.1, August 4, 2023. This invention discloses an extracellular electron transfer anaerobic ammonium oxidation process. This process utilizes the extracellular absorption capacity of Anammox bacteria, using the anode of a microbial electrolysis cell as an extracellular electron acceptor to break the anaerobic ammonium oxidation process's dependence on nitrite, thereby achieving the treatment of ammonia-nitrogen wastewater under oxygen- and nitrite-free conditions. The process achieves an ammonia-nitrogen removal efficiency of approximately 17% during its initial startup phase, stabilizing at approximately 65% ​​after 20 days.

[0007] Liu Xiuhong, Sun Anran, Huang Songqing, et al. An electrochemical anaerobic ammonium oxidation device and its operation method [P]. Beijing: CN202310189927.3, 2023-10-24. This invention provides an electrochemical anaerobic ammonium oxidation device that efficiently enriches functional bacteria by gradually increasing the pressure during startup, allowing anaerobic ammonium oxidation bacteria to be rapidly and massively adsorbed on the anode and cathode carbon cloth electrodes. The electrochemical anaerobic ammonium oxidation device comprises a nitrogen tank, an inlet water tank, a magnetic stirrer, an anode carbon cloth, a cathode carbon cloth, an electrochemical anaerobic ammonium oxidation reactor, an anode platinum electrode holder, a cathode platinum electrode holder, a DC power supply, a gas sampling bag, a sampling valve, an outlet water tank, a dissolved oxygen meter, a peristaltic pump, an inlet valve, a cylindrical rotor with a PTFE sealing cover, a data acquisition system, and a computer. This invention focuses on the rapid enrichment of anaerobic ammonium oxidation bacteria through voltage stimulation and the improvement of the traditional anaerobic ammonium oxidation denitrification pathway, which is an optimization and improvement of the traditional anaerobic ammonium oxidation process.

[0008] The process system studied in this invention is no longer the traditional anaerobic ammonium oxidation process, but uses the extracellular absorption ability of Anammox bacteria to convert NH4 + -N is completely oxidized to N2 without NO2 - -N and NO3 - -N accumulation. In the initial stage, adding a small amount of nitrite nitrogen increases the anode anaerobic ammonium oxidation denitrification rate, accelerates the start-up of the electroactive anaerobic ammonium oxidation system, and improves the denitrification efficiency of the electroactive anaerobic ammonium oxidation system. Summary of the Invention

[0009] The present invention aims to provide a method for improving the denitrification rate of electroactive anaerobic ammonium oxidation to solve the problem of low denitrification rate of anode anaerobic ammonium oxidation in microbial electrochemical systems.

[0010] The technical solutions of the present invention are as follows:

[0011] A method for increasing the denitrification rate of electroactive anaerobic ammonium oxidation, comprising:

[0012] In the microbial electrochemical system, ammonia nitrogen (NH4 + -N) is an electron donor, the anode of the microbial electrolysis cell, nitrite nitrogen (NO2 - -N) is the electron acceptor. Based on the different electron transfer efficiencies of anaerobic ammonium-oxidizing bacteria to different electron acceptors (nitrite nitrogen, anode), and the effect of nitrite nitrogen electron acceptors on the growth, metabolism and denitrification rate of anaerobic ammonium-oxidizing bacteria in the electrochemical system, a method for regulating the addition of nitrite nitrogen to improve the anode anaerobic ammonium oxidation denitrification rate in the microbial electrochemical system was constructed, thereby achieving the improvement of the anode anaerobic ammonium oxidation denitrification performance in the microbial electrochemical system.

[0013] Among them, nitrite nitrogen / ammonia nitrogen = 0.1~0.7 (mass ratio). Regulating the dosage of nitrite nitrogen can affect the nitrogen degradation rate of the anodic anaerobic ammonium oxidation process. After optimization, it was determined that when nitrite nitrogen / ammonia nitrogen = 0.4 (mass ratio), the anodic anaerobic ammonium oxidation denitrification rate in the microbial electrochemical system was the highest, that is, the denitrification performance of the electroactive anaerobic ammonium oxidation was the best.

[0014] The method of the present invention can be implemented by using an extracellular electron transfer type anaerobic ammonium oxidation system device, which includes: a multi-channel potentiostat, a computer, a digital display constant temperature stirring water bath, a cylindrical rotor, a glass reactor, a carbon felt (anode), a saturated silver chloride reference electrode, a titanium mesh (cathode), an anode platinum sheet electrode clamp, a cathode platinum sheet electrode clamp, a gas sampling bag, a sampling and water inlet and outlet;

[0015] The carbon felt (anode), saturated silver chloride reference electrode, and titanium mesh (cathode) are all placed in a glass reactor. The carbon felt (anode) and titanium mesh (cathode) are fixed with anode platinum sheet electrode clamps and cathode platinum sheet electrode clamps, respectively. The carbon felt (anode), saturated silver chloride reference electrode, and titanium mesh (cathode) are respectively connected to a multi-channel potentiostat, which is connected to a computer. The top of the glass reactor is equipped with sampling and water inlet and outlet ports, and another opening is provided to connect to a gas sampling bag. A cylindrical rotor is placed in the glass reactor, and the glass reactor is placed in a digital display constant temperature stirring water bath.

[0016] Specifically, the method for improving the denitrification rate of electroactive anaerobic ammonium oxidation according to the present invention comprises the following steps:

[0017] (1) Carbon felt pretreatment: The carbon felt was soaked in alkali solution, acid solution and anhydrous ethanol respectively, then washed with water and dried for use;

[0018] The preferred alkali solution is 1mol / L NaOH solution, and the acid solution is 1mol / L H2SO4 solution; soak in the alkali solution, acid solution, and anhydrous ethanol for 12 hours respectively, wash with water three times, and then dry at 105°C for later use;

[0019] (2) Reactor operation: A single-chamber three-electrode glass reactor was used, with carbon felt as the anode, titanium mesh as the cathode, and saturated silver chloride as the reference electrode forming a three-electrode system. A multi-channel potentiostat was used to apply a voltage of 0.6 V vs. SHE to the reaction system.

[0020] (3) Inoculation: The anaerobic ammonium oxidation sludge was cleaned and purged with argon until the dissolved oxygen was lower than 0.5 mg / L before inoculation. The treated sludge was inoculated into the reactor. The volume of the inoculated anaerobic ammonium oxidation sludge was 20% of the effective volume of the reactor.

[0021] Specifically, the anaerobic ammonium oxidation sludge was washed with 0.9% NaCl solution and centrifuged at 5000 rpm for 10 min, and the washing process was repeated three times;

[0022] (4) Water inlet: Nitrogen-containing wastewater was purged with argon until the dissolved oxygen was less than 0.5 mg / L, and then introduced into the reactor. The hydraulic retention time of the wastewater in the reactor was 72 h, the pH of the wastewater was maintained at 7.7 ± 0.2, the reactor temperature was controlled at 35 ± 0.2 °C, the magnetic stirrer speed was 450 r / min, and 80% of the effective volume of the reactor was replaced each time the water was changed;

[0023] In nitrogen-containing wastewater, nitrite nitrogen / ammonia nitrogen = 0.1 to 0.7, particularly preferably nitrite nitrogen / ammonia nitrogen = 0.4;

[0024] (5) Sampling: Turn off the multi-channel potentiostat and magnetic stirrer, allow the solution to settle, and extract water samples through the sampling port for measurement and analysis.

[0025] The main principles of the present invention are as follows:

[0026] The present invention provides a method for increasing the rate of electroactive anaerobic ammonium oxidation (ANAMMOX) denitrification, solving the problem of low ANAMMOX denitrification rate at the anode in microbial electrochemical systems. Based on the differences in the electron transfer efficiency of ANAMMOX bacteria for different electron acceptors (nitrite nitrogen, electrode), the present invention studies the regulatory effect of a small amount of nitrite nitrogen electron acceptor on the growth, metabolism, and denitrification rate of ANAMMOX bacteria in the electrochemical system. A method for regulating the addition of nitrite nitrogen to increase the ANAMMOX denitrification rate at the anode in the microbial electrochemical system is constructed, thereby improving the ANAMMOX denitrification performance at the anode in the microbial electrochemical system.

[0027] By detecting the ammonia nitrogen (NH4 + -N), nitrite nitrogen (NO2 - -N) and nitrate nitrogen (NO3 - -N), and further calculated the nitrite nitrogen (NO2 - -N) is consumed, so as to determine the appropriate nitrite nitrogen (NO2- -N) dosage, namely nitrite nitrogen (NO2 - -N) / ammonia nitrogen (NH4 + -N) dosing ratio.

[0028] The beneficial effects of the present invention are:

[0029] (1) The method of the present invention can improve the denitrification rate of the anodic anaerobic ammonium oxidation process in the microbial electrochemical system, and ultimately improve the denitrification performance of the electroactive anaerobic ammonium oxidation.

[0030] (2) The present invention can increase the denitrification rate of the anode anaerobic ammonium oxidation process in the microbial electrochemical system by adding a small amount of nitrite nitrogen.

[0031] (3) The method of the present invention is applied to treat ammonia nitrogen-containing wastewater, has low operating costs, is economical and long-lasting, and has wide application value in sewage treatment and water environment protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 : Schematic diagram of the device structure of the anode anaerobic ammonia oxidation in the microbial electrolysis cell; including: multi-channel constant potential instrument-1, computer-2, digital display constant temperature stirring water bath-3, cylindrical rotor-4, glass reactor-5, carbon felt (anode)-6, saturated silver chloride reference electrode-7, titanium mesh (cathode)-8, anode platinum sheet electrode clamp-9, cathode platinum sheet electrode clamp-10, gas sampling bag-11, sampling and water inlet and outlet-12.

[0033] Figure 2 : Graph showing nitrogen degradation rate of anaerobic ammonia oxidation at the anode of the microbial electrolysis cell in Example 1. DETAILED DESCRIPTION

[0034] The present invention is further described below through specific embodiments in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited thereto.

[0035] Example 1:

[0036] The device of anaerobic ammonium oxidation at the anode of microbial electrolysis cell is as follows: Figure 1 As shown, it includes: a multi-channel potentiostat 1, a computer 2, a digital display constant temperature stirring water bath 3, a cylindrical rotor 4, a glass reactor 5, a carbon felt (anode) 6, a saturated silver chloride reference electrode 7, a titanium mesh (cathode) 8, an anode platinum sheet electrode clamp 9, a cathode platinum sheet electrode clamp 10, a gas sampling bag 11, and a sampling and water inlet and outlet 12;

[0037] The carbon felt (anode) 6, saturated silver chloride reference electrode 7, and titanium mesh (cathode) 8 are all arranged in the glass reactor 5, and the carbon felt (anode) 6 and titanium mesh (cathode) 8 are respectively fixed by the anode platinum sheet electrode clamp 9 and the cathode platinum sheet electrode clamp 10; the carbon felt (anode) 6, saturated silver chloride reference electrode 7, and titanium mesh (cathode) 8 are respectively connected to the multi-channel constant potential instrument 1, and the multi-channel constant potential instrument 1 is connected to the computer 2; the top of the glass reactor 5 is provided with a sampling and water inlet and outlet 12, and another opening is provided to connect to the gas sampling bag 11; the cylindrical rotor 4 is placed in the glass reactor 5, and the glass reactor 5 is placed in a digital display constant temperature stirring water bath 3.

[0038] The specific operation process is as follows:

[0039] (1) Carbon felt pretreatment: The carbon felt was immersed in 1 mol / L NaOH, 1 mol / L H2SO4 and anhydrous ethanol for 12 h, then washed with water three times and dried at 105 °C for later use.

[0040] (2) Reactor operation: A single-chamber three-electrode glass reactor with an effective volume of 1 L was used. A carbon felt (9 × 2 × 0.3 cm) was used as the anode, a titanium mesh (9 × 2 × 0.1 cm) was used as the cathode, and a saturated silver chloride (saturated potassium chloride, 0.197 V vs. SHE) was used as the reference electrode to form a three-electrode system. A multi-channel potentiostat (CHI1000C, China) was used to apply a voltage of 0.6 V vs. SHE to the reaction system, and the current was continuously detected every 60 s.

[0041] (3) Inoculation: Wash the anaerobic ammonium oxidation sludge with 0.9% NaCl solution and centrifuge at 5000 rpm for 10 min. Repeat the washing process three times. Before inoculation, purge the sludge with argon until the dissolved oxygen is less than 0.5 mg / L. Inoculate the treated sludge into the bioreactor. The volume of the inoculated anaerobic ammonium oxidation sludge is 20% of the effective volume of the reactor. The mixed liquor suspended solids (MLSS) concentration of the inoculum is 13.65 g·L -1 .

[0042] (4) Influent: Add different NO2 into the four bioreactors (R1, R2, R3, R4) - -N / NH4 + The reactor was used to simulate nitrogenous wastewater with a NH3-N ratio of 0.7, 0.4, 0.1, and 0, respectively. The hydraulic retention time (HRT) of the wastewater in the reactor was 72 hours. The pH of the nitrogenous wastewater was maintained at 7.7 ± 0.2. Argon was used to purge the reactor prior to the experiment, keeping the dissolved oxygen below 0.5 mg / L. The reactor temperature was controlled at 35 ± 0.2°C, and the magnetic stirrer speed was 450 rpm. Each water change replaced 80% of the reactor's effective volume.

[0043] The simulated nitrogen-containing wastewater contains 200 mg / L of ammonium chloride (NH4Cl), 140 mg / L, 80 mg / L, 20 mg / L and 0 mg / L of sodium nitrite (NaNO2), 100 mg / L of calcium chloride (CaCl2), 30 mg / L of potassium dihydrogen phosphate (KH2PO4), 70 mg / L of magnesium chloride (MgCl·6H2O), 100 mg / L of sodium bicarbonate (NaHCO3), 1 mL / L of trace element A solution and 1 mL / L of trace element B solution.

[0044] The components of trace element solution A are as follows: 5000 mg / L of ferric sulfate (FeSO4·7H2O) and 5000 mg / L of ethylenediaminetetraacetic acid (EDTA).

[0045] The components of trace element B solution are as follows: ethylenediaminetetraacetic acid (EDTA) 15000 mg / L, zinc sulfate (ZnSO4·7H2O) 430 mg / L, cobalt chloride (CoCl2·6H2O) 240 mg / L, manganese chloride (MnCl2·4H2O) 990 mg / L, copper sulfate (CuSO4·5H2O) 250 mg / L, sodium molybdate (Na2MoO4·2H2O) 220 mg / L, boric acid (H3BO3) 14 mg / L, nickel chloride (NiCl2·6H2O) 190 mg / L and sodium selenate (NaSeO4·10H2O) 210 mg / L.

[0046] (5) Sampling: Turn off the magnetic stirrer and let it settle for 10 minutes. Draw water samples through the sampling port once every 24 hours for measurement and analysis.

[0047] (6) Measurement of different NO2 - -N / NH4 + -N ratio of the reactor effluent ammonia nitrogen (NH4 + -N), nitrite nitrogen (NO2 - -N) and nitrate nitrogen (NO3 - -N).

[0048] like Figure 2 As shown in Figure 2, the nitrogen degradation rate of the anode anaerobic ammonium oxidation process was calculated after the nitrite nitrogen in the reactor was consumed. The nitrogen metabolism rate of the reactors R1-R3 with nitrite nitrogen was higher than that without nitrite nitrogen. Among them, the nitrogen metabolism rate of the R2 reactor reached 20.71 mg·L -1 ·d -1 The nitrogen metabolism rate of R4 was 9.57 mg·L -1 ·d -1 , the nitrogen metabolism rate of R2 is 2.2 times that of R5. The R2 reactor is the best nitrite nitrogen dosage, that is, NO2 - -N / NH4+ -N＝0.4。

Claims

1. A method for increasing the rate of denitrification by electroactive anaerobic ammonium oxidation, characterized in that: The method comprises: In a microbial electrolysis cell, ammonia nitrogen in nitrogen-containing wastewater is used as an electron donor, and the anode and nitrite nitrogen of the microbial electrolysis cell are used as electron acceptors. Based on the different electron transfer efficiencies of anaerobic ammonium-oxidizing bacteria to different electron acceptors, and the effect of nitrite nitrogen electron acceptors on the growth, metabolism and denitrification rate of anaerobic ammonium-oxidizing bacteria in the microbial electrolysis cell, a method for regulating the addition of nitrite nitrogen to increase the anode anaerobic ammonium oxidation denitrification rate in the microbial electrolysis cell was constructed, thereby improving the anode anaerobic ammonium oxidation denitrification performance in the microbial electrolysis cell. The method is implemented by using an extracellular electron transfer anaerobic ammonium oxidation system device, which includes: a multi-channel potentiostat, a computer, a digital display constant temperature stirring water bath, a cylindrical rotor, a glass reactor, carbon felt, a saturated silver chloride reference electrode, a titanium mesh, an anode platinum electrode clamp, a cathode platinum electrode clamp, a gas sampling bag, a sampling port, and a water inlet and outlet; A carbon felt, a saturated silver chloride reference electrode, and a titanium mesh are all placed in a glass reactor. The carbon felt and titanium mesh are secured with an anode platinum electrode clamp and a cathode platinum electrode clamp, respectively. The carbon felt, saturated silver chloride reference electrode, and titanium mesh are connected to a multi-channel potentiostat, which is connected to a computer. The top of the glass reactor is equipped with a sampling port and a water inlet and outlet, as well as an opening for connecting to a gas sampling bag. A cylindrical rotor is placed in the glass reactor, which is placed in a digitally displayed constant-temperature stirring water bath. The method comprises the following steps: (1) Carbon felt pretreatment: The carbon felt is soaked in alkali solution, acid solution and anhydrous ethanol respectively, then washed with water and dried for use; (2) Reactor operation: A single-chamber three-electrode glass reactor was used, with carbon felt as the anode, titanium mesh as the cathode, and saturated silver chloride as the reference electrode forming a three-electrode system. A multi-channel potentiostat was used to apply a voltage of 0.6 V vs. SHE to the reaction system. (3) Inoculation: Clean the anaerobic ammonium oxidation sludge. Before inoculation, purge it with argon until the dissolved oxygen is lower than 0.5 mg / L. Inoculate the treated sludge into the reactor. The volume of the inoculated anaerobic ammonium oxidation sludge is 20% of the effective volume of the reactor. (4) Influent: Nitrogenous wastewater was purged with argon until the dissolved oxygen was less than 0.5 mg / L, and then introduced into the reactor. The hydraulic retention time of the wastewater in the reactor was 72 h, the pH of the wastewater was maintained at 7.7 ± 0.2, the reactor temperature was controlled at 35 ± 0.2 °C, the cylindrical rotor speed was 450 r / min, and 80% of the effective volume of the reactor was replaced each time the water was changed; In nitrogen-containing wastewater, the mass ratio of nitrite nitrogen to ammonia nitrogen is 0.4; (5) Sampling: Turn off the multi-channel potentiostat and cylindrical rotor, let the solution settle, and extract water samples through the sampling port for measurement and analysis.

2. The method for improving the denitrification rate of electroactive anaerobic ammonium oxidation according to claim 1, characterized in that: In step (1), the alkali solution is 1 mol / L NaOH solution, and the acid solution is 1 mol / L H2SO4 solution; the alkali solution, acid solution, and anhydrous ethanol are soaked for 12 hours respectively, washed with water three times, and then dried at 105°C for use.

3. The method for improving the denitrification rate of electroactive anaerobic ammonium oxidation according to claim 1, wherein: In step (3), the anaerobic ammonium oxidation sludge was washed with 0.9% NaCl solution and centrifuged at 5000 rpm for 10 min. The washing process was repeated three times.

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