Device and method for realizing deep autotrophic nitrogen removal of sludge digestion liquid based on double-MABR alternate intermittent aeration

Abstract

The invention discloses a method for realizing deep autotrophic nitrogen removal of sludge digestion liquid based on alternate intermittent aeration of a double-membrane aeration bio-membrane reactor (MABR). The process device comprises a sludge digestion liquid raw water tank, a single-stage double-MABR reactor, two MABR devices and a water outlet tank. According to the method, sludge digestion liquid enters the single-stage double-MABR reactor, the two MABR devices are alternately and intermittently aerated, the state of one aeration and one aeration stopping is always kept, and ammonia nitrogen in raw water is converted into nitrite through ammonia oxidizing bacteria enriched on the inner side of an MABR membrane. And simultaneously supplying to anaerobic ammonium oxidation bacteria enriched on the outer sides of the two MABR membranes through matrix diffusion for denitrification and generation of nitrate. Denitrifying bacteria enriched on the outer side of the MABR membrane utilize raw water organic matters to drive short-cut denitrification to synchronously supply nitrite to anaerobic ammonium oxidation bacteria so as to realize deep autotrophic nitrogen removal. According to the invention, a double-anaerobic ammonia oxidation reaction hot area is constructed through alternate intermittent aeration of double MABRs, and efficient deep autotrophic nitrogen removal of the sludge digestion liquid can be stably realized.

Description

Technical Field

[0001] This invention relates to a device and method for achieving deep autotrophic denitrification of sludge digestate based on alternating intermittent aeration using dual MABR, belonging to the field of wastewater biological treatment technology. Background Technology

[0002] With the acceleration of urbanization and the expansion of wastewater treatment scale, the output of excess sludge from wastewater treatment plants is increasing daily. Sludge digestion, as an important means of sludge stabilization and volume reduction, produces digestate containing high concentrations of carbon and nitrogen pollutants. Direct discharge without effective treatment will cause serious pollution to aquatic environments, leading to a series of environmental problems such as eutrophication. The ammonia nitrogen concentration in sludge digestate is as high as 500-3000 mg / L, and the carbon-to-nitrogen ratio is often below 2, classifying it as typical high-nitrogen, low-carbon wastewater. Traditional denitrification pathways based on nitrification-denitrification for treating sludge digestate suffer from high energy consumption, large sludge production, large footprint of multi-stage reactors, and low denitrification efficiency. While resulting in a high carbon footprint, these methods also fail to meet the current dual demands of improving wastewater treatment quality and efficiency while saving energy and reducing emissions.

[0003] The emergence of anaerobic ammonia oxidation (AAO) technology provides a low-carbon and environmentally friendly solution for treating high-ammonia nitrogen wastewater. Anaerobic ammonia oxidizing bacteria (AOBs) can directly convert ammonia nitrogen and nitrite into nitrogen gas for removal under anaerobic conditions without the need for oxygen or organic carbon sources. The short-cut nitrification (ammonia nitrogen oxidation to nitrite) coupled with AOBs significantly reduces aeration volume and external carbon source consumption, perfectly matching the "high ammonia, low carbon" characteristics of the digester broth. However, AOBs have slow proliferation rates, are sensitive to the environment, and are easily inhibited by substrates and organic matter. Enriching AOBs while simultaneously inhibiting nitrite-oxidizing bacteria (NOBs) to achieve a stable nitrite supply is also difficult. These factors lead to slow start-up and unstable operation of the AAO process. Furthermore, the difficulty in removing nitrates, a byproduct of the AOB reaction, also limits the removal of total nitrogen in the system, making deep denitrification difficult.

[0004] Membrane-aerated biofilm reactors (MABRs) utilize hollow fiber membranes for bubble-free oxygen supply, offering advantages such as low supply pressure, high oxygen mass transfer efficiency, and low aeration energy consumption. The biofilm formed on its surface can diffuse counter-currently with the substrate, creating a steady-state gradient of oxygen inside and anoxic outside. This forms an aerobic zone on the membrane surface, conducive to the growth of nitrifying bacteria, while an anoxic / anaerobic zone forms on the outer layer of the biofilm, providing an ideal habitat for anaerobic ammonia oxidizing bacteria and denitrifying bacteria, naturally matching the spatial division of labor required for functional bacteria in anaerobic ammonia oxidation processes. However, combining MABR and anammox processes presents several challenges: 1) In MABR systems where sludge removal is difficult, there is a lack of effective NOB inhibition strategies to stably achieve short-cut nitrification. Once NOB is enriched in the biofilm, its activity is difficult to inhibit; 2) Existing intermittent aeration strategies only target a single MABR unit. During the aeration shutdown phase, ammonia nitrogen and COD concentrations increase, and denitrifying bacteria compete with anammox bacteria for nitrite, resulting in low treatment load, limited autotrophic denitrification, and low total nitrogen removal rate in single-stage intermittent aeration systems; 3) Matching the activities of anammox and short-cut nitrification in the biofilm of a single MABR unit is difficult. Low anammox activity leads to excessive nitrite in the effluent, while low short-cut nitrification activity results in low total nitrogen removal load and difficulty in removing the byproduct nitrate; 4) Multi-stage series MABR processes are complex in structure, occupy a large area, have high infrastructure costs, and require precise operation control due to different operating parameters at each stage, which hinders widespread application. Summary of the Invention

[0005] To address or alleviate the problems associated with combining MABR and anaerobic ammonium oxidation processes in the prior art, and to achieve high-rate and high-efficiency autotrophic denitrification of sludge digestate, this invention proposes a device and method for deep autotrophic denitrification of sludge digestate based on alternating intermittent aeration in a dual MABR system. A single-stage bioreactor containing a reaction tank and an inclined plate sedimentation tank, capable of ensuring the coexistence of the MABR unit and flocs, is employed. Short-cut nitrification in the MABR is achieved through an in-situ strategy of high free ammonia combined with alternating intermittent aeration in the dual MABR system. Based on this, anaerobic ammonium oxidation and denitrifying bacteria biofilm formation are achieved in the dual MABR system. The short-cut nitrification performance and anaerobic ammonium oxidation activity are stabilized over the long term by adjusting the alternating intermittent aeration ratio, thus constructing a stable anaerobic ammonium oxidation reaction hotspot within the dual MABR system. This invention creatively proposes an alternating intermittent aeration strategy for the dual MABR unit, which effectively suppresses NOB activity in the biofilm while fully utilizing the high oxygen transfer rate of the MABR, enabling high-rate short-cut nitrification to be achieved with a single MABR unit. Furthermore, by leveraging the spatial characteristics of the MABR biofilm, anaerobic ammonia oxidizing bacteria and denitrifying bacteria are enriched in the outer layer of the biofilm. The short-cut denitrification driven by denitrifying bacteria removes the byproduct nitrate while simultaneously supplying nitrite, a substrate for anaerobic ammonia oxidation. The dual anaerobic ammonia oxidation reaction hot zones can effectively match the high-rate short-cut nitrification and short-cut denitrification activities, thus achieving deep autotrophic nitrogen removal in a single-stage system with a small footprint. This invention has the advantages of simple operation, high processing capacity, and low-carbon, economical deep nitrogen removal, and possesses strong potential for widespread application.

[0006] The objective of this invention is achieved through the following technical solution: a device and method for achieving deep autotrophic denitrification of sludge digestate based on alternating intermittent aeration using dual MABRs. The device includes: The sludge digestion liquid raw water tank (1), single-stage dual MABR reactor (2), MABR device 1 (3), MABR device 2 (4), and effluent tank (5) are included. The single-stage dual MABR reactor (2) includes a reaction tank and an inclined plate sedimentation tank that are connected to each other. The inclined plate sedimentation tank is located at the effluent end of the reaction tank. The reaction tank is equipped with an online pH / DO measuring device (2.2) and a stirring device (2.3). The MABR device 1 (3) includes multiple hollow fiber membranes and is equipped with an aeration pump (3.1), a rotor flow meter (3.2), and a tail gas outlet (3.3). The MABR device 2 (4) includes multiple hollow fiber membranes and is equipped with an aeration pump (4.1), a rotor flow meter (4.2), and a tail gas outlet (4.3).

[0007] The raw water tank (1) for sludge digestion liquid is connected to the single-stage dual MABR reactor (2) via an inlet pump (2.1), and the single-stage dual MABR reactor (2) is connected to the outlet water tank (5) via a drain pump (2.4).

[0008] The method includes the following steps: 1) Short-cut nitrification start-up phase of dual MABR system: Wastewater treatment plant sludge was inoculated into a single-stage dual MABR reactor (2) to achieve a sludge concentration of 3000±500 mg / L after mixing. Unfilmed MABR units 1 (3) and 2 (4) were then installed, with a total filling rate of 80–120 m³. 2 / m 3 The digestate in the raw water tank (1) of sludge digestion liquid is pumped into the single-stage dual MABR reactor (2) by the inlet pump (2.1). After the reaction, it is discharged from the top of the inclined plate sedimentation tank to the effluent tank (5) by the drain pump (2.4). The hydraulic retention time (HRT) is controlled to be 2 to 4 days. The oxygen supply pressure of the two MABR devices is controlled to be 20 to 50 kPa. The dual MABRs alternately perform intermittent aeration to achieve in-situ biofilm formation. That is, when MABR device 1 (3) is aerated, MABR device 2 (4) is stopped. Conversely, when MABR device 2 (4) is aerated, MABR device 1 (3) is stopped. The aeration-stop ratio of intermittent aeration is between 1:1 and 3:1. The duration of a single aeration is 0.5 to 2 hours. Combined with the in-situ high free ammonia environment formed by the high ammonia nitrogen of the sludge digestion liquid itself, the enrichment of ammonia-oxidizing bacteria (AOB) and the inhibition of nitrite-oxidizing bacteria (NOB) activity are achieved. When the AOB activity of the system is greater than 2 gN / (m 2 When the nitrite accumulation rate (nitrite concentration / (nitrite concentration + nitrate concentration) * 100%) is ≥ 85%, short-cut nitrification is successfully started.

[0009] 2) Autotrophic denitrification operation stage of the dual MABR system: Anaerobic ammonia oxidizing flocculent sludge at a volume ratio of 5% (relative to the effective reactor volume) was added to the stable short-cut nitrification system to acclimate and attach anaerobic ammonia oxidizing bacteria. The aeration pressure (10–50 kPa) and the intermittent aeration-to-stop ratio of the dual MABR units (1:1–3:1) were adjusted to simultaneously supply nitrite to the anaerobic ammonia oxidizing bacteria during short-cut nitrification and short-cut denitrification. When the anaerobic ammonia oxidizing bacteria activity in both MABR unit 1 (3) and MABR unit 2 (4) was greater than 1.5 gN / (m³), the anaerobic ammonia oxidizing bacteria were successfully acclimated to the system. 2 •d) Biofilm formation was successful. The subsequent HRT was controlled at 2–4 days. After 20–30 days of operation, the system's total nitrogen removal rate was ≥90%, and the autotrophic denitrification contribution was ≥50%, achieving deep autotrophic denitrification of the sludge digestate.

[0010] This invention patent has the following advantages: 1) Stable achievement and maintenance of MABR short-cut nitrification under continuous operation of a single-stage reactor: Unlike traditional intermittent aeration operation, this invention can rapidly achieve MABR short-cut nitrification without interrupting the nitrification process or causing continuous accumulation of ammonia nitrogen and COD. This is achieved through flexible alternating intermittent aeration combined with in-situ high free ammonia inhibition, without the addition of chemical inhibitors or sludge discharge. Furthermore, after the introduction of anaerobic ammonia oxidation, nitrite is consumed through a dual anaerobic ammonia oxidation hot zone, and the short-cut nitrification performance is maintained through an alternating intermittent aeration operation mode.

[0011] 2) Constructing a dual anaerobic ammonium oxidation (ANO) reaction hot zone to synergistically achieve high load and deep nitrogen removal: Utilizing the MABR's "internal aerobic-external anoxic" reverse diffusion gradient, AOB, anaerobic ammonium oxidizing bacteria, and denitrifying bacteria are simultaneously enriched within a single MABR, achieving synergistic effects of high-speed short-cut nitrification, anaerobic ammonium oxidation, and short-cut denitrification. By constructing a dual ANO reaction hot zone, the activities of high-rate short-cut nitrification and short-cut denitrification are efficiently matched; short-cut denitrification can simultaneously remove nitrate, a byproduct of anaerobic ammonium oxidation, and replenish nitrite substrate, ultimately achieving deep autotrophic nitrogen removal with zero carbon source addition to the sludge digestate in a single-stage system, significantly improving treatment load and total nitrogen removal efficiency.

[0012] 3) Simple process structure, small footprint, and low operating energy consumption, significantly reducing engineering complexity and carbon emissions: This invention integrates a single-stage bioreactor with a dual MABR device and a flocculent sludge system, achieving synergistic operation of short-cut nitrification, anaerobic ammonia oxidation, and short-cut denitrification without the need for multi-stage series reactors, significantly simplifying the process flow and operational control requirements. Simultaneously, the MABR's bubble-free oxygen supply method greatly improves oxygen utilization efficiency, and combined with an autotrophic denitrification pathway, significantly reduces aeration energy consumption and external carbon source requirements, effectively reducing the system's carbon footprint while decreasing sludge production. This process is particularly suitable for treating sludge digestate with high ammonia nitrogen and low carbon sources, and can be extended to other high ammonia nitrogen wastewater treatment, offering advantages such as low infrastructure costs, high operational economics, and strong engineering replicability. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a device and method for achieving deep autotrophic denitrification of sludge digestate based on alternating intermittent aeration using dual MABRs.

[0014] Figure 2 This is a schematic diagram of the denitrification mechanism of a deep autotrophic denitrification system for sludge digestate based on alternating intermittent aeration of dual MABR devices (taking MABR device 1 aeration and MABR device 2 aeration stoppage as an example). Detailed Implementation

[0015] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0016] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples: like Figure 1 As shown, the apparatus used includes a sludge digester raw water tank (1), a single-stage dual MABR reactor (2), MABR device 1 (3), MABR device 2 (4), and an effluent tank (5). The single-stage dual MABR reactor (2) includes a reaction tank and an inclined plate sedimentation tank that are connected to each other. The inclined plate sedimentation tank is located at the effluent end of the reaction tank. The reaction tank is equipped with an online pH / DO measuring device (2.2) and a stirring device (2.3). The MABR device 1 (3) includes multiple hollow fiber membranes and is equipped with an aeration pump (3.1), a rotor flow meter (3.2), and a tail gas outlet (3.3). The MABR device 2 (4) includes multiple hollow fiber membranes and is equipped with an aeration pump (4.1), a rotor flow meter (4.2), and a tail gas outlet (4.3).

[0017] The raw water tank (1) for sludge digestion liquid is connected to the single-stage dual MABR reactor (2) via an inlet pump (2.1), and the single-stage dual MABR reactor (2) is connected to the outlet water tank (5) via a drain pump (2.4).

[0018] The experiment used hydrolyzed sludge digestate from the Gaobeidian wastewater treatment plant as raw water. Specific water quality parameters were as follows: COD concentration 2800-3500 mg / L, NH4+ concentration... + -N concentration 2500-3000 mg / L, NO2 - -N≤1.2mg / L, NO3 - -N≤1.0mg / L. Experimental system as follows: Figure 1 As shown, all reactors are made of plexiglass, with an effective volume of 4L.

[0019] 1) Short-cut nitrification start-up phase of dual MABR system: Wastewater treatment plant sludge was inoculated into a single-stage dual MABR reactor (2) to achieve a sludge concentration of 3000 mg / L after mixing. Un-filmed MABR units 1 (3) and 2 (4) were then installed, with a total filling rate of 100 m³ / L. 2 / m 3The digestate in the raw water tank (1) of sludge digestion liquid is pumped into the single-stage dual MABR reactor (2) by the inlet pump (2.1). After the reaction, it is discharged from the top of the inclined plate sedimentation tank to the effluent tank (5) by the drain pump (2.4). The hydraulic retention time (HRT) is controlled to be 3 days. The oxygen supply pressure of the two MABR devices is controlled to be 25 kPa. The two MABRs alternately perform intermittent aeration to achieve in-situ biofilm formation. That is, when MABR device 1 (3) is aerated, MABR device 2 (4) is stopped. Conversely, when MABR device 2 (4) is aerated, MABR device 1 (3) is stopped. The aeration-stop ratio of intermittent aeration is 1:1, and the duration of a single aeration is 2 hours. After 20 days of long-term operation, the overall AOB activity of the system is 2.5 gN / (m 2 ·d), and the nitrite accumulation rate is ≥95%, thus successfully achieving short-cut nitrification.

[0020] 2) Autotrophic denitrification operation stage of the dual MABR system: Anaerobic ammonia oxidation flocculent sludge was added at a volume ratio of 5% to the system for stable short-cut nitrification, to acclimate and promote biofilm formation of anaerobic ammonia oxidizing bacteria. The aeration pressure was adjusted to 30 kPa, and the aeration-to-stop ratio of the dual MABR unit was set at 2:1 to meet the demand for nitrite supply for the anaerobic ammonia oxidation enriched in the dual MABR membrane unit, simultaneously supporting both short-cut nitrification and short-cut denitrification. Figure 2 As shown, ammonia nitrogen in the raw digester is oxidized to nitrite by AOB enriched inside the biofilm of MABR unit 1. Subsequently, some of the nitrite and ammonia nitrogen are removed by anaerobic ammonia oxidizing bacteria on the outside of the biofilm, while some diffuses into the substrate and is removed by anaerobic ammonia oxidation on the outside of MABR unit 2. The byproduct nitrate is then reduced to nitrite by denitrifying bacteria on the outside of the dual MABR unit using organic matter in the raw water and supplied to the anaerobic ammonia oxidizing bacteria again, thus constructing a dual anaerobic ammonia oxidation reaction hot zone and achieving deep autotrophic denitrification in a single-stage system.

[0021] After 60 days of operation, the activity of anaerobic ammonia oxidizing bacteria in both MABR unit 1 (3) and MABR unit 2 (4) was greater than 2 gN / (m 2 •d) is considered a successful biofilm formation. Based on this, the HRT is controlled at 4 days. After 30 days of operation, the total nitrogen removal rate of the system is ≥90%, and the autotrophic denitrification contribution is ≥50%. The system achieves deep autotrophic denitrification of sludge digestate.

[0022] The test results show that after the system stabilizes, the COD concentration in the effluent is less than 1000 mg / L, and the NH4 concentration is less than 1000 mg / L. + -N concentration <50mg / L, NO2 - -N < 25 mg / L, NO3 - -N < 50 mg / L.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0025] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0027] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0028] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A device and method for deep autotrophic denitrification of sludge digestion liquid based on double MABR alternating intermittent aeration, characterized in that, The device comprises: a sludge digestion liquid raw water tank (1), a single-stage double MABR reactor (2), a MABR device 1 (3), a MABR device 2 (4), and a effluent tank (5); the single-stage double MABR reactor (2) comprises a reaction pool body and an inclined plate sedimentation pool body in communication with each other, the inclined plate sedimentation pool body is arranged at the effluent end of the reaction pool body, and the reaction pool body is provided with a pH / DO online measuring device (2.2) and a stirring device (2.3); the MABR device 1 (3) comprises a plurality of hollow fiber membrane filaments, is provided with an aeration pump (3.1), a rotor flowmeter (3.2), and a tail gas outlet (3.3); the MABR device 2 (4) comprises a plurality of hollow fiber membrane filaments, is provided with an aeration pump (4.1), a rotor flowmeter (4.2), and a tail gas outlet (4.3); The sludge digestion liquid raw water tank (1) is connected with the single-stage double MABR reactor (2) through a water inlet pump (2.1), and the single-stage double MABR reactor (2) is connected with the effluent tank (5) through a water outlet pump (2.4); The method comprises the following steps: 1) Double MABR system short-cut nitrification start-up stage: The single-stage double-MABR reactor (2) is inoculated with residual sludge from a sewage treatment plant, and the mixed sludge concentration is 3000±500 mg / L. The un-membraneed MABR device 1 (3) and the MABR device 2 (4) are arranged, and the total filling rate is 80-120 m 2 / m 3 ; The sludge digestion liquid in the sludge digestion liquid raw water tank (1) is pumped into the single-stage double-MABR reactor (2) by the water inlet pump (2.1), and after the reaction, it is discharged from the top of the inclined plate sedimentation tank to the water outlet tank (5) by the water outlet pump (2.4), and the hydraulic retention time (HRT) is controlled to be 2-4 days; the oxygen supply pressure of the two MABR devices is controlled to be 20-50 kPa, and the double-MABR is alternately intermittently aerated to realize in-situ membrane formation, that is, when the MABR device 1 (3) is aerated, the MABR device 2 (4) is in a stop state, and vice versa, when the MABR device 2 (4) is aerated, the MABR device 1 (3) is in a stop state, the aeration and stop ratio of intermittent aeration is between 1:1 and 3:1, the single aeration time is 0.5-2 hours, the in-situ high free ammonia environment formed by the combined sludge digestion liquid itself high ammonia nitrogen cooperates to realize the enrichment of ammonia oxidizing bacteria (AOB) and the inhibition of nitrite oxidizing bacteria (NOB) activity; when the system AOB activity is greater than 2 g-N / (m 2 ·d), and the nitrite accumulation rate (nitrite concentration / (nitrite concentration+nitrate concentration) *100%) is greater than or equal to 85%, the short-cut nitrification is started successfully; 2) Double MABR system autotrophic denitrification operation stage: The volume ratio of anaerobic ammonia oxidation floc sludge is 5% (relative to the effective volume of the reactor) to the stable short-cut nitrification system, and the anaerobic ammonia oxidation bacteria domestication and biofilm are carried out; the aeration pressure (10-50 kPa) and the intermittent aeration exposure ratio (1:1-3:1) between the double MABR devices are adjusted, so that the short-cut nitrification and short-cut denitrification are synchronized to supply nitrite for the anaerobic ammonia oxidation bacteria; when the anaerobic ammonia oxidation bacteria activity of MABR device 1 (3) and MABR device 2 (4) is greater than 1.5 g-N / (m 2 ·d), the biofilm is successfully formed; after the subsequent control of HRT for 2-4 days, the system total nitrogen removal rate is greater than or equal to 90% after 20-30 days of operation, the autotrophic denitrification contribution is greater than or equal to 50%, and the sludge digestion liquid deep autotrophic denitrification is realized.

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