Sewage treatment method based on interspecific electron transfer

Abstract

The invention provides a sewage treatment method based on interspecific electron transfer, and belongs to the technical field of sewage treatment. The sewage treatment method based on interspecific electron transfer comprises the following steps: introducing sewage to be treated into a sewage treatment device, wherein the sewage treatment device comprises ammonia oxidizing bacteria, carbon sequestration bacteria and sulfate reducing bacteria; under an anaerobic condition, in a sewage treatment device, ammonia oxidizing bacteria take an oxidation reaction by taking ammonia nitrogen in to-be-treated sewage as an electron donor, carbon sequestration bacteria take a reduction reaction by taking inorganic carbon in the to-be-treated sewage as an electron acceptor, and the ammonia oxidizing bacteria and the carbon sequestration bacteria are combined by utilizing interspecific electron transfer capability of sulfate reducing bacteria; the to-be-treated sewage is denitrified through metabolism interaction among multiple strains, and treated sewage is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a sewage treatment method based on interspecies electron transfer. Background Art

[0002] Biological denitrification of sewage is an important process link in the secondary treatment of sewage treatment plants. It usually uses nitrification-denitrification reaction to promote the oxidation of ammonia nitrogen into nitrate nitrogen through aeration, and uses the carbon source of the influent to cause denitrification reaction. It has problems such as high operating energy consumption and high treatment cost. At the same time, a large amount of greenhouse gases are produced in nitrification and denitrification reactions, especially nitrous oxide, which is the main contributor to the carbon footprint of sewage treatment plants.

[0003] The traditional anaerobic ammonium oxidation process can save 50-60% of aeration energy consumption and does not require an organic carbon source. It is an energy-saving and consumption-reducing wastewater treatment denitrification process that uses ammonia nitrogen as an electron donor and nitrite as an electron acceptor to achieve denitrification. The stable acquisition of nitrite is one of the important factors restricting the traditional anaerobic ammonium oxidation reaction. In recent years, a lot of research has been carried out on the accumulation of nitrite based on short-range nitrification or partial denitrification reactions, but there are still problems such as unstable operation and complex control technology. Summary of the invention

[0004] In view of the above technical problems, the present invention provides a sewage treatment method based on interspecies electron transfer, in order to at least partially solve the above technical problems. The specific technical solutions provided by the present invention are as follows.

[0005] According to an embodiment of the present invention, a sewage treatment method based on interspecies electron transfer is provided, comprising: passing the sewage to be treated into a sewage treatment device, the sewage treatment device comprising ammonia oxidizing bacteria, carbon fixing bacteria and sulfate reducing bacteria; under anaerobic conditions, in the sewage treatment device, the ammonia oxidizing bacteria undergo an oxidation reaction using ammonia nitrogen in the sewage to be treated as an electron donor, the carbon fixing bacteria undergo a reduction reaction using inorganic carbon in the sewage to be treated as an electron acceptor, and the ammonia oxidizing bacteria and the carbon fixing bacteria are combined by utilizing the interspecies electron transfer ability of the sulfate reducing bacteria, so as to denitrify the sewage to be treated through metabolic interactions between multiple bacterial species to obtain treated sewage.

[0006] In an embodiment of the present invention, the sewage treatment method based on interspecies electron transfer provided by the present invention utilizes the interspecies electron transfer ability of sulfate-reducing bacteria, combines ammonia oxidizing bacteria and carbon-fixing bacteria, and performs sewage treatment through metabolic interactions between multiple bacterial species. It can treat inorganic wastewater without the need to add additional organic carbon sources, thereby reducing sewage treatment costs and operating energy consumption, saving energy and reducing emissions. It does not require aeration, saves energy consumption, has a faster denitrification rate, and carbon fixation reactions can also occur during the sewage treatment process to achieve carbon emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 A schematic diagram of a sewage treatment device in one embodiment of the present invention;

[0008] Figure 2 This is a graph showing the test results of ammonia nitrogen in sewage in Example 1 of the present invention;

[0009] Figure 3 This is a graph showing the test results of nitrate nitrogen in sewage in Example 1 of the present invention;

[0010] Figure 4 This is a graph showing the test results of inorganic carbon in sewage in Example 1 of the present invention.

[0011] Description of reference numerals:

[0012] 100—water inlet unit;

[0013] 200—anaerobic ammonium oxidation reactor; 201—water inlet pump; 202—reflux pump;

[0014] 300—water outlet unit;

[0015] 400—Gas collection unit. DETAILED DESCRIPTION

[0016] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0017] In view of the problems of high energy consumption, high operating costs, high carbon emissions and the like in existing sewage denitrification processes, the present invention proposes a sewage treatment method based on interspecies electron transfer.

[0018] Interspecific electron transfer (IET) is an important mode of interaction between microorganisms, which is of great significance to the geobiochemical cycle and environmental pollution remediation. Direct interspecific electron transfer (DIET) is a newly discovered electron transfer pathway between microorganisms. Its electron transfer efficiency is higher than that of traditional interspecific hydrogen / formate transfer, providing a new perspective for studying the phenomenon of microbial mutualism. Microorganisms obtain energy through the extracellular electron transfer (EET) process, using redox proteins, electron mediators or nanowires to transfer electrons generated intracellularly to extracellular electron acceptors or transfer electrons from extracellular electron donors to intracellular cells. This electron transfer process is not only crucial for the energy metabolism of microorganisms, but also has broad application potential in environmental remediation and biofuel production. Some sulfate-reducing bacteria (SRB), such as Desulfovibrio, have interspecific electron transfer functions, which use conductive flagella (e-pili) and cytochrome c (Cytc) to achieve extracellular electron transfer.

[0019] Based on this, the present invention provides a sewage treatment method based on interspecies electron transfer, which utilizes the extracellular electron transfer ability of sulfate-reducing bacteria (SRB), uses ammonia nitrogen as an electron donor and inorganic carbon as an electron acceptor to achieve the reaction process of sewage denitrification, which involves the metabolic interaction of various bacteria such as ammonia oxidizing bacteria, sulfate-reducing bacteria and carbon-fixing bacteria. Compared with nitrification-denitrification and traditional anaerobic ammonia oxidation reactions, this method does not require aeration or organic carbon sources, and biological carbon fixation occurs, saving energy consumption and chemical agent input, and achieving carbon emission reduction, which is expected to enable sewage treatment plants to achieve negative carbon emissions.

[0020] Specifically, according to an embodiment of the present invention, a sewage treatment method based on interspecies electron transfer is provided, comprising: passing the sewage to be treated into a sewage treatment device, the sewage treatment device comprising ammonia oxidizing bacteria, carbon fixing bacteria and sulfate reducing bacteria; under anaerobic conditions, in the sewage treatment device, the ammonia oxidizing bacteria undergo an oxidation reaction using ammonia nitrogen in the sewage to be treated as an electron donor, the carbon fixing bacteria undergo a reduction reaction using inorganic carbon in the sewage to be treated as an electron acceptor, and the ammonia oxidizing bacteria and the carbon fixing bacteria are combined by utilizing the interspecies electron transfer ability of sulfate reducing bacteria, so as to denitrify the sewage to be treated through metabolic interactions between multiple bacterial species to obtain treated sewage.

[0021] In an embodiment of the present invention, the sewage treatment method based on interspecies electron transfer provided by the present invention utilizes the interspecies electron transfer ability of sulfate-reducing bacteria, combines ammonia oxidizing bacteria and carbon-fixing bacteria, and performs sewage treatment through metabolic interactions between multiple bacterial species. It can treat inorganic wastewater without the need to add additional organic carbon sources, thereby reducing sewage treatment costs and operating energy consumption, saving energy and reducing emissions. It does not require aeration, saves energy consumption, has a faster denitrification rate, and carbon fixation reactions can also occur during the sewage treatment process to achieve carbon emission reduction.

[0022] Specifically, the use of interspecies electron transfer ability of sulfate-reducing bacteria to combine ammonia-oxidizing bacteria and carbon-fixing bacteria includes: sulfate-reducing bacteria use organic carbon released by carbon-fixing bacteria and sulfate in the sewage to be treated to proliferate, while sulfate-reducing bacteria exert interspecies electron transfer ability to make oxidation reaction and reduction reaction occur synergistically, and realize multi-species interaction of ammonia-oxidizing bacteria, carbon-fixing bacteria and sulfate-reducing bacteria. Among them, sulfate-reducing bacteria exert interspecies electron transfer ability includes: receiving electrons released by oxidation reaction of ammonia-oxidizing bacteria through conductive flagella and cytochrome c of sulfate-reducing bacteria, and transferring electrons to carbon-fixing bacteria for reduction reaction.

[0023] According to an embodiment of the present invention, ammonia oxidizing bacteria are introduced through anaerobic ammonia oxidation sludge; sulfate reducing bacteria are introduced from anaerobic digestion sludge; and carbon fixing bacteria are introduced from anaerobic ammonia oxidation sludge and anaerobic digestion sludge. Different microorganisms are introduced by introducing different sludges into the sewage treatment device. Among them, the introduction of ammonia oxidizing bacteria oxidizes the ammonia nitrogen in the sewage to be treated into nitrogen gas; the introduction of carbon fixing bacteria converts the inorganic carbon in the sewage to be treated into organic matter in the cells, and releases it in the sewage to be further used by other microorganisms for proliferation; the introduction of sulfate reducing bacteria can reduce the sulfate in the sewage to be treated to reduced sulfide (such as sulfide ions or sulfur), promote the circulation of sulfur elements, and at the same time exert the ability of interspecies electron transfer, transfer electrons between ammonia oxidizing bacteria and carbon fixing bacteria, and promote the synergistic occurrence of denitrification oxidation reaction and carbon fixation reduction reaction of the sewage to be treated.

[0024] According to an embodiment of the present invention, the mass ratio of anaerobic ammonia oxidation sludge and anaerobic digestion sludge in the sewage treatment device is 1:1, which helps to maintain the balance of the microbial community in the sewage treatment device. The ammonia oxidizing bacteria and some carbon-fixing bacteria in the anaerobic ammonia oxidation sludge can cooperate with the sulfate-reducing bacteria and another part of the carbon-fixing bacteria in the anaerobic digestion sludge. The total sludge concentration in the sewage treatment device is 5~7g / L, which can ensure that there are a sufficient number of microorganisms to treat the pollutants in the sewage to be treated. Within this concentration range, the microorganisms have sufficient contact opportunities with the pollutants in the sewage to be treated. If the sludge concentration is too high, it may cause sludge swelling, resulting in sludge loss, affecting the treatment effect of the sewage to be treated. At the same time, too high sludge concentration may also cause blockage of the treatment device and increase the equipment maintenance cost. The total sludge age in the sewage treatment device is 30~60d, and the growth rate of anaerobic ammonia oxidation bacteria is relatively slow. A longer sludge age can provide them with enough time to grow and reproduce. For sulfate-reducing bacteria, their growth also requires a certain amount of time to adapt to the sewage environment and function. The appropriate sludge age allows them to complete the transition from the adaptation period to the logarithmic growth period within the device, making full use of the sulfate in the sewage to be treated for metabolic activities and reducing the sulfate to hydrogen sulfide. Carbon-fixing bacteria also benefit from a longer sludge age. The process of synthesizing organic carbon compounds from inorganic carbon is relatively complex and requires time to accumulate sufficient energy and substances. Furthermore, the influent water quality and water volume of the sewage treatment plant may fluctuate. A longer sludge age makes the microbial community more adaptable.

[0025] According to an embodiment of the present invention, the dissolved oxygen solubility in the sewage treatment device is ≤0.05 mg / L. Nitrogen stripping pretreatment can be used to maintain low dissolved oxygen conditions (dissolved oxygen ≤0.05 mg / L) in the reactor inlet water. Ammonia oxidizing bacteria are a type of strictly anaerobic microorganisms, and high concentrations of dissolved oxygen will inhibit their activity. When the dissolved oxygen concentration is ≤0.05 mg / L, suitable living conditions can be provided for ammonia oxidizing bacteria, so that they can normally convert ammonia nitrogen into nitrogen gas. For sulfate-reducing bacteria, a low dissolved oxygen environment is conducive to their proliferation and interspecies electron transfer function. For carbon-fixing bacteria, carbon dioxide or other inorganic carbon sources can be used for growth in an anaerobic environment, and low dissolved oxygen concentrations can ensure that they play a role in their own suitable ecological niche, thereby promoting the stability of the entire microbial ecosystem. The redox potential in the sewage treatment device is maintained at -140~-60mV. The redox potential is an important indicator of microbial activity. By monitoring and maintaining the redox potential, the growth and metabolic state of microorganisms in the sewage treatment device can be intuitively understood. If the redox potential deviates from this range, it means that the microbial community has been disturbed, such as being impacted by toxic and harmful substances or the balance between microorganisms has been broken. At this time, the redox potential can be restored by adjusting the influent water quality, adding nutrients, etc., so as to ensure the normal activity of microorganisms and maintain the stable operation of the sewage treatment device.

[0026] According to an embodiment of the present invention, the hydraulic retention time of the sewage treatment device is 1~2d, ensuring that there is enough time for the microorganisms and sewage to fully contact and react. For the decomposition of organic matter in sewage, whether through anaerobic digestion or the metabolic activities of other microorganisms, a certain amount of time is required. The metabolic activities of microorganisms such as ammonia oxidizing bacteria, sulfate-reducing bacteria and carbon-fixing bacteria have their own time scales. This time range can match the growth cycle and metabolic reaction rate of these microorganisms, so that the microorganisms can grow, reproduce and metabolize normally in the sewage treatment device, and will not be unable to complete the necessary reactions due to the hydraulic retention time being too short, nor will it cause the microorganisms to overgrow in the device or other abnormal conditions due to being too long. The temperature of the sewage treatment device is 28~30℃, which is the suitable growth temperature for many microorganisms involved in sewage treatment. For anaerobic ammonia oxidizing bacteria, this temperature range is conducive to maintaining its high enzyme activity. Sulfate-reducing bacteria and carbon-fixing bacteria can also maintain a good growth state in this temperature range. Keeping the temperature at 28~30℃ can make the sewage treatment process more stable. When the temperature is within this range, the growth and metabolic rates of microorganisms are relatively stable, and there will be no mass death of microorganisms or a sharp drop in activity due to drastic temperature fluctuations.

[0027] According to an embodiment of the present invention, the sewage treatment device includes an anaerobic ammonium oxidation reactor using an upflow process; the water inlet of the anaerobic ammonium oxidation reactor is located at the bottom of the anaerobic ammonium oxidation reactor, and the water outlet of the anaerobic ammonium oxidation reactor is located at the top of the anaerobic ammonium oxidation reactor. The sewage to be treated flows from bottom to top in the anaerobic ammonium oxidation reactor, and this flow mode can provide relatively stable hydraulic conditions. Compared with other flow modes, the upflow type can reduce the short circuit and dead zone phenomenon of the water flow, and can also prevent the loss of sludge. Since the sewage to be treated flows upward, the sludge is more likely to settle at the bottom of the anaerobic ammonium oxidation reactor under the action of gravity. For the anaerobic ammonium oxidation sludge and anaerobic digestion sludge in the anaerobic ammonium oxidation reactor, this helps to maintain sufficient biomass in the anaerobic ammonium oxidation reactor, thereby ensuring the efficiency of the treatment of the sewage to be treated. From the perspective of the substrate (pollutants in the sewage to be treated), the water inlet is located at the bottom so that pollutants such as ammonia nitrogen and sulfate in the sewage to be treated can begin to contact with microorganisms at the bottom of the reactor. From the perspective of the product, the upflow process helps to discharge the product (such as nitrogen, hydrogen sulfide, etc.). The water outlet of the anaerobic ammonium oxidation reactor is connected to the water outlet unit, and the water outlet pipe is sealed below the liquid level of the water outlet unit, which can effectively prevent the outside air (containing oxygen) from entering the anaerobic ammonium oxidation reactor. At the same time, this liquid seal method can prevent harmful gases (such as hydrogen sulfide, etc.) generated in the anaerobic ammonium oxidation reactor from escaping into the surrounding environment. The liquid seal structure helps to stabilize the hydraulic conditions of the anaerobic ammonium oxidation reactor and prevent the short-circuit flow phenomenon of sewage (the sewage to be treated is directly discharged without treatment).

[0028] According to an embodiment of the present invention, the anaerobic ammonium oxidation reactor is provided with a return pipe for returning the sewage to be treated in the anaerobic ammonium oxidation reactor. Further, the return ratio of the return pipe is 400% to 600%. A higher return ratio can give the ammonia nitrogen in the sewage to be treated more contact opportunities with the microorganisms. The returned sewage contains various organic matter and sulfates, which can be further decomposed and transformed by microorganisms when passing through the anaerobic ammonium oxidation reactor again. A higher return ratio helps to stabilize the hydraulic conditions in the anaerobic ammonium oxidation reactor. In the sewage treatment process, the stability of hydraulic conditions is very important for the growth and reaction of microorganisms. The returned sewage can buffer the changes in the influent flow rate and water quality, and prevent hydraulic shock in the anaerobic ammonium oxidation reactor. At the same time, through the return flow, the microbial ecosystem in the anaerobic ammonium oxidation reactor can remain relatively stable. In some embodiments of the present invention, the anaerobic ammonium oxidation reactor adopts a continuous flow process, which enables the sewage to continuously enter the anaerobic ammonium oxidation reactor, ensuring the continuity of the treatment process. Compared with the intermittent process, there is no frequent start and stop phase, and the microorganisms can always be in a relatively stable working state. For microorganisms, the continuous flow process provides a relatively stable growth environment. The growth and metabolism of microorganisms is a continuous process. The continuous flow process can keep the substrate (pollutants in sewage) concentration, temperature, redox potential and other environmental factors relatively stable. This stable environment is conducive to the domestication of microorganisms. In the process of continuous flow, microorganisms can gradually adapt to the changes in the composition and concentration of pollutants in sewage.

[0029] Figure 1 Schematic diagram of a sewage treatment device in one embodiment of the present invention.

[0030] In some embodiments of the present invention, Figure 1 As shown, the sewage treatment device includes:

[0031] A water inlet unit 100 is used to introduce sewage to be treated;

[0032] Anaerobic ammonium oxidation reactor 200, in which the wastewater to be treated undergoes reactions such as denitrification and carbon fixation;

[0033] The wastewater discharged from the anaerobic ammonium oxidation reactor enters the water outlet unit 300;

[0034] Gas collecting unit 400, the gas discharged from the anaerobic ammonium oxidation reactor enters the gas collecting unit 400;

[0035] The water inlet pump 201 is used to pump the sewage to be treated into the anaerobic ammonium oxidation reactor from the bottom water inlet;

[0036] A reflux pump 202 is connected to the top reflux outlet and the bottom reflux inlet of the anaerobic ammonium oxidation reactor to promote mass transfer, contact and reaction between the sludge and the sewage to be treated;

[0037] The anaerobic ammonium oxidation reactor 200 adopts an upflow process, with the water inlet located at the bottom and the water outlet located at the top. At the same time, there are a reflux outlet and a reflux inlet at the top and bottom of the anaerobic ammonium oxidation reactor 200 for refluxing the sewage in the anaerobic ammonium oxidation reactor.

[0038] In some embodiments of the present invention, during the laboratory experiment, the NH4 + :HCO3 - The molar ratio is 1:1~1:2; NH4 + :SO4 2- The molar ratio is 2:1; NH4 + -N concentration is 100~400mg / L.

[0039] The present invention is further described below by examples and related test experiments. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, it is obvious that one or more embodiments may also be implemented without these specific details. And, in the absence of conflict, the details in the following embodiments may be combined into other feasible embodiments at will. All instruments, consumables and reagents in the following examples, if not otherwise specified, may be obtained from commercial sources.

[0040] Example 1

[0041] This embodiment 1 is Figure 1 The sewage treatment plant shown denitrifies the sewage.

[0042] The sewage to be treated is pumped into the bottom of the anaerobic ammonium oxidation reactor by using an inlet pump. The continuous flow anaerobic ammonium oxidation reactor is equipped with a reflux, which returns from the top of the reactor to the bottom through a reflux pump, and denitrification is carried out through biological reactions. The effluent enters the outlet tank through the outlet.

[0043] The influent of the anaerobic ammonium oxidation reactor is water distribution, in which the concentration of ammonia nitrogen is 100-200 mg / L, NH4 + :HCO3 - The molar ratio is 1:2, the N / S molar ratio is 2:1, and no NO2 is added to the influent water - and NO3 -, the influent is prepared with ammonium sulfate, sodium bicarbonate, sodium sulfate and other agents, and the required trace elements are supplemented. The hydraulic retention time (HRT) of the anaerobic ammonium oxidation reactor is controlled at 2d, and the temperature of the anaerobic ammonium oxidation reactor is controlled at 28-30°C. The influent is pretreated with nitrogen stripping, and the anaerobic ammonium oxidation reactor maintains an anaerobic environment. The dissolved oxygen concentration (DO) is controlled below 0.05mg / L, the oxidation-reduction potential (ORP) is between -140~-60mV, and the pH is between 7.4 and 7.9. The reflux ratio of the anaerobic ammonium oxidation reactor is 500%. The inoculated sludge in the anaerobic ammonium oxidation reactor is a mixed sludge of traditional anaerobic ammonium oxidation sludge and anaerobic digestion sludge in a 1:1 sludge mass ratio. The sludge age is 30d. After inoculation, the sludge concentration in the anaerobic ammonium oxidation reactor is 6~7g / L;

[0044] Figure 2 This is a graph showing the test results of ammonia nitrogen in sewage in Example 1 of the present invention; Figure 3 This is a graph showing the test results of nitrate nitrogen in sewage in Example 1 of the present invention; Figure 4 This is a graph showing the test results of inorganic carbon in sewage in Example 1 of the present invention.

[0045] like Figure 2 As shown in the figure, the anaerobic ammonium oxidation reactor reached equilibrium after 15 days, indicating that the start-up period of the anaerobic ammonium oxidation reaction was 6 to 12 days, and the ammonia nitrogen removal rate in the stable operation stage could reach 0.08 to 0.10 kgN / (m 3 ·d), the ammonia nitrogen removal rate reaches 85~95%. Figure 3 As shown, the test found that the effluent contained almost no NO3 - and NO2 - , outlet water NO2 - -N and NO3 - -N concentration is between 0.1-1 mg / L, indicating that N2 is the main denitrification product. Figure 4 As shown in Figure 2, the removal rate of inorganic carbon (IC) is 0.6~0.9 kgC / (m 3 ·d). The molar ratio of ammonia nitrogen removal and inorganic carbon removal (ΔN / ΔC) in the inlet and outlet water is 1.0~1.3, which proves that inorganic carbon is the electron acceptor of the denitrification reaction.

[0046] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sewage treatment method based on interspecies electron transfer, comprising: Passing the sewage to be treated into a sewage treatment device, wherein the sewage treatment device includes ammonia oxidizing bacteria, carbon fixing bacteria and sulfate reducing bacteria; Under anaerobic conditions, in the sewage treatment device, the ammonia oxidizing bacteria use the ammonia nitrogen in the sewage to be treated as an electron donor to undergo an oxidation reaction, and the carbon-fixing bacteria use the inorganic carbon in the sewage to be treated as an electron acceptor to undergo a reduction reaction. The ammonia oxidizing bacteria and the carbon-fixing bacteria are combined by utilizing the interspecies electron transfer ability of the sulfate-reducing bacteria, so as to denitrify the sewage to be treated through metabolic interactions between multiple bacterial species to obtain treated sewage.

2. The method according to claim 1, wherein: The step of utilizing the interspecies electron transfer capability of the sulfate-reducing bacteria to combine the ammonia-oxidizing bacteria and the carbon-fixing bacteria comprises: The sulfate-reducing bacteria utilize the organic carbon released by the carbon-fixing bacteria and the sulfate in the wastewater to be treated to proliferate, and at the same time, the sulfate-reducing bacteria exert their interspecies electron transfer ability to make the oxidation reaction and the reduction reaction occur synergistically, thereby realizing the multi-species interaction of the ammonia oxidizing bacteria, carbon-fixing bacteria and sulfate-reducing bacteria.

3. The method according to claim 2, wherein: The ability of the sulfate-reducing bacteria to perform interspecies electron transfer includes: The electrons released by the oxidation reaction of the ammonia oxidizing bacteria are received by the conductive flagella and cytochrome c of the sulfate-reducing bacteria, and the electrons are transferred to the carbon-fixing bacteria for reduction reaction.

4. The method according to claim 1, wherein: The ammonia oxidizing bacteria are introduced through anaerobic ammonium oxidation sludge; The sulfate-reducing bacteria are introduced from anaerobic digestion of sludge; The carbon-fixing bacteria are introduced together with the anaerobic ammonium oxidation sludge and the anaerobic digestion sludge.

5. The method according to claim 4, wherein: The mass ratio of anaerobic ammonium oxidation sludge to anaerobic digestion sludge in the sewage treatment device is 1:1; The total sludge concentration in the sewage treatment device is 5-7 g / L.

6. The method according to claim 1, wherein: The dissolved oxygen solubility in the sewage treatment device is ≤ 0.05 mg / L; The redox potential in the sewage treatment device is maintained at -140~-60mV.

7. The method according to claim 1, wherein: The hydraulic retention time of the sewage treatment device is 1 to 2 days; The temperature of the sewage treatment device is 28~30℃.

8. The method according to any one of claims 1 to 7, wherein: The sewage treatment device includes an anaerobic ammonium oxidation reactor using an upflow process; The water inlet of the anaerobic ammonium oxidation reactor is located at the bottom of the anaerobic ammonium oxidation reactor, and the water outlet of the anaerobic ammonium oxidation reactor is located at the top of the anaerobic ammonium oxidation reactor.

9. The method according to claim 8, wherein: The anaerobic ammonium oxidation reactor is provided with a return pipe for returning the wastewater to be treated in the anaerobic ammonium oxidation reactor.

10. The method according to claim 9, wherein: The reflux ratio of the reflux pipeline is 400% to 600%.

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