A sewage treatment device based on an anaerobic ammonia oxidation process

Abstract

The application provides a sewage treatment device based on an anaerobic ammonia oxidation process, which comprises a water inlet pool used for storing domestic sewage to be treated, an anaerobic reactor adopting a De-Anammox reactor, the anaerobic reactor being used for receiving the domestic sewage from the water inlet pool and stirring anaerobic ammonia oxidation bacteria fillers by a stirrer to perform anaerobic reaction, an MBR reactor used for receiving effluent from the anaerobic reactor and performing MBR reaction, an AxMBR analysis device used for performing AxMBR analysis on one or both of the anaerobic reactor and the MBR reactor, domesticating and culturing anaerobic ammonia oxidation bacteria with high activity to obtain optimal temperature and DO concentration, and an AxMBR control device used for controlling environmental parameters of the anaerobic reactor and the MBR reactor according to the result of AxMBR analysis performed by the AxMBR analysis device. The application solves the problem that the application of the anaerobic ammonia oxidation technology in domestic sewage treatment is limited.

Description

Technical Field

[0001] This invention relates to the field of anaerobic ammonia oxidation process, and more specifically to a wastewater treatment device based on anaerobic ammonia oxidation process. Background Technology

[0002] The continuous development of urbanization has led to a year-on-year increase in the discharge of municipal sewage. More efficient and low-cost denitrification treatment of domestic sewage is of profound significance for reducing nitrogen pollution in water bodies. Currently, although the denitrification processes for domestic sewage that have been built and are in operation in my country are diverse and relatively mature, they all essentially rely on nitrification and denitrification to achieve denitrification, and all have disadvantages such as high energy consumption, high sludge production, and poor denitrification effect on sewage with low carbon-to-nitrogen ratios. Anaerobic ammonia oxidation (ANAO), as a novel wastewater denitrification process, uses nitrite as an electron acceptor to oxidize ammonia nitrogen into nitrogen gas. It has advantages such as high denitrification efficiency, no need for external organic carbon sources, high load, low residual sludge production, and low operating costs. Therefore, ANAO-based processes are widely favored by researchers and engineers and are widely used in the treatment of high-ammonia-nitrogen wastewater, such as landfill leachate, sludge digestion liquid, aquaculture wastewater, and industrial wastewater. However, the engineering application of ANAO in domestic sewage treatment is extremely rare. The relatively low concentration of ammonia nitrogen in domestic sewage and its susceptibility to temperature fluctuations are unfavorable for the accumulation of nitrite and the proliferation of anaerobic ammonia oxidizing bacteria, thus limiting the application of anaerobic ammonia oxidation technology in domestic sewage treatment. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the purpose of this invention is to provide a wastewater treatment device based on anaerobic ammonia oxidation (AmmO) technology, which constructs an AxMBR process coupled with AmmO. This AxMBR process not only retains anaerobic ammonia oxidizing bacteria in the system but also maintains stable effluent quality, thus possessing the dual advantages of efficient nitrogen removal and stable process operation of AmmO, solving the problem of limited application of AmmO technology in domestic wastewater treatment.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] This invention provides a wastewater treatment device based on an anaerobic ammonia oxidation process, comprising:

[0006] The inlet tank is used to store domestic sewage awaiting treatment.

[0007] The anaerobic reactor, employing the De-Anammox reactor design, is equipped with anaerobic ammonia-oxidizing bacteria packing material and a stirrer. The anaerobic reactor receives domestic sewage from the influent tank and uses the stirrer to agitate the anaerobic ammonia-oxidizing bacteria packing material for anaerobic reaction. The anaerobic reactor also includes an online pH monitoring system for measuring the pH value of the liquid within the reactor, an alkali pump, and an alkali tank for storing alkali. If the online pH monitoring system detects that the pH value of the liquid within the anaerobic reactor is outside a preset range, the alkali in the alkali tank can be pumped into the anaerobic reactor as needed.

[0008] An MBR reactor is used to receive effluent from an anaerobic reactor and perform the MBR reaction. The MBR reactor includes an online pH monitoring system and a reflux pump to measure the pH value of the liquid within the reactor. If the online pH monitoring system detects that the pH value of the liquid within the MBR reactor is outside a preset range, the reflux liquid from the MBR reactor is pumped back and combined with domestic sewage into the anaerobic reactor. The MBR reactor also includes baffles, a ceramic membrane module, a level controller, a backwash controller, an aeration pump, and a filtration / backwash pump. The baffles and ceramic membrane module are installed inside the MBR reactor. The aeration pump is connected to the ceramic membrane module. The liquid in the MBR reactor treated by the ceramic membrane module is the effluent from the AxMBR system. The filtration / backwash pump is used to pump the effluent from the AxMBR system into an effluent tank and also to backwash the liquid from the effluent tank back into the MBR reactor via the backwash controller and the level controller.

[0009] The AxMBR analysis device is used to perform AxMBR analysis on one or two specified types of anaerobic reactors and MBR reactors, to cultivate and acclimate anaerobic ammonia-oxidizing bacteria with successful and highly active culture, to obtain the optimal temperature and DO concentration, and to determine the microbial situation at the pilot scale. The AxMBR analysis includes conventional index analysis, denitrification effect analysis of the anaerobic reactor, microbial community structure analysis of the entire wastewater treatment device, effluent effect analysis at each stage, and denitrification effect and correlation analysis of the anaerobic reactor. The stages include the start-up and acclimatization stage, stage I, stage II, and stage III.

[0010] The AxMBR control device is used to control the environmental parameters of the anaerobic reactor and the MBR reactor based on the results of AxMBR analysis performed by the AxMBR analyzer.

[0011] Furthermore, a flow regulating valve and a flow meter are provided between the inlet pool and the anaerobic reactor; the domestic sewage in the inlet pool is pumped into the anaerobic reactor by an inlet pump.

[0012] Furthermore, both the anaerobic reactor and the MBR reactor are cylindrical tanks with a diameter of 1.2m and an effective volume of 1.0m³. 3 .

[0013] Furthermore, activated carbon is laid at the bottom of the anaerobic reactor, and an effluent sedimentation tank is provided on the inner wall of the anaerobic reactor, through which the effluent from the anaerobic reactor is fed to the MBR reactor.

[0014] Furthermore, conventional index analysis included the analysis of COD and NH4 in the influent and effluent of anaerobic reactors and MBR reactors at different stages. + -N, NO2 - -N, NO3 - The concentrations of -N and TN were analyzed. COD was analyzed using a microwave-assisted closed digestion method with potassium dichromate; TN was analyzed using an alkaline potassium persulfate digestion method with ultraviolet spectrophotometry; NH4... + -N was analyzed using Nessler's reagent spectrophotometry; NO2 - -N was analyzed using the N-(1-neyl)-ethylenediamine spectrophotometric method; NO3 - -N analysis by UV-Vis spectrophotometry.

[0015] Furthermore, the nitrogen removal efficiency analysis of the anaerobic reactor includes the following steps: calculating the actual influent TN and NH4+ of the anaerobic reactor. + -N, NO2 - -N and NO3 - -N concentration, and then compared with TN and NH4 in the effluent of the anaerobic reactor. + -N, NO2 - -N and NO3 - The difference between -N concentrations is used to calculate the corresponding concentration change.

[0016] Furthermore, the microbial community structure of the entire wastewater treatment device was analyzed. Sludge samples of the specified sludge sample type were collected according to the corresponding stage. The sludge samples were dehydrated and stored in a -20°C freezer. DNA was extracted from the sludge samples using the PowerSoil DNA Separation Kit, and microbial sequencing was performed on the sludge samples. The diversity of the microbial community within the system was analyzed. DNA was extracted, and after verifying its purity, the DNA was amplified by polymerase chain reaction. PCR was used to amplify the target DNA fragments while cutting them. The target DNA fragments were separated and purified by denaturing gradient gel electrophoresis, in which DNA fragments of different microorganisms were fixed at different positions on the gel.

[0017] Furthermore, the sludge sample types include influent sludge, anaerobic ammonia oxidizing bacteria, MBR reactor packing sludge, MBR reactor suspended sludge, and anaerobic reactor suspended sludge.

[0018] Furthermore, the analysis of the effluent quality at each stage includes the following steps:

[0019] Initial acclimatization phase: After adding anaerobic and aerobic mixed activated sludge, the hydraulic retention time (HRT) is gradually shortened from 48 hours to 8 hours; when the effluent NH4... + When the -N concentration is below 5 mg / L and the effluent TN concentration is below 15 mg / L, the HRT is shortened to the next stage until the HRT = 8 h, at which point the effluent NH4+... + The concentration of -N decreased from 30.48 mg / L to 10.05 mg / L, and the concentration of TN in the effluent decreased from 33.5 mg / L to 18.53 mg / L, indicating that the AxMBR system was successfully started up and acclimatized, and the next stage of experiments can be carried out.

[0020] Phase I: This refers to the stable operation of the AxMBR system after successful startup, i.e., nitrification-denitrification-MBR coupling; effluent COD concentration maintained at 1.02-6.09 mg / L; effluent NH4... + -N concentration maintained between 2.22-4.64 mg / L; effluent NO2 - -N concentration maintained between 0.84-3.26 mg / L; effluent NO3 - -N concentration was maintained at 6.60-8.85 mg / L; effluent TN concentration was maintained at 11.33-14.67 mg / L;

[0021] Phase II: This phase involves the addition of laboratory-cultured, highly active anaerobic ammonia-oxidizing bacteria to the anaerobic reactor after Phase I, i.e., AxMBR coupling; the overall COD concentration in the AxMBR system effluent remains below 6.40 mg / L; the effluent NH4... + -N concentration was generally maintained below 5.00 mg / L, and TN concentration in the effluent was generally maintained below 14.87 mg / L;

[0022] Phase III: This phase involves increasing DO (dissolved oxygen) to maintain the effluent quality of the AxMBR system when the temperature drops below 25℃, essentially restoring the nitrification-denitrification-MBR coupling. The effluent COD concentration is maintained between 1.54-7.03 mg / L, with an average concentration of 4.11 mg / L; the effluent NH4... + -N concentration remained between 1.22 and 4.20 mg / L, with an average concentration of 2.84 mg / L; effluent NO2 - -N concentration remained between 0.12 and 0.67 mg / L, with an average concentration of 0.29 mg / L; effluent NO3 - -N concentration was maintained at 6.12-12.36 mg / L, with an average concentration of 9.49 mg / L; TN concentration in the effluent was maintained at 10.08-14.93 mg / L, with an average concentration of 13.45 mg / L.

[0023] Furthermore, the denitrification effect of the anaerobic reactor and its correlation analysis were conducted, including the denitrification effect analysis of the anaerobic reactor in stages II and III, and the contribution analysis of Anammox and nitrification-denitrification to the denitrification of the AxMBR system under mesophilic conditions.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] (1) The AxMBR system of the present invention can efficiently treat campus domestic sewage with relatively high nitrogen content. It can operate stably in different operating stages and the effluent quality basically meets the Class A standard of the pollutant discharge standard of urban sewage treatment plants (GB18918-2002).

[0026] (2) Temperature and DO are important parameters, and the present invention optimizes them in different operating stages through the AxMBR analysis device.

[0027] (3) This invention establishes a pilot-scale AxMBR treatment process for domestic wastewater, successfully starts the AxMBR system, and after a period of stable operation, adds laboratory-cultured anaerobic ammonia-oxidizing bacteria with high activity to the anaerobic reactor. The COD and NH4 content in the influent and effluent at different stages are analyzed. + -N, NO2 - -N, NO3 - The concentrations of indicators such as -N and TN were analyzed to explore their removal efficiency, and the optimal temperature and DO concentration were determined. The relative abundance of microbial communities in the sludge at each stage was analyzed to determine the microbial situation at the pilot-scale level, aiming to provide a reference for the engineering application of anaerobic ammonia oxidation in domestic wastewater treatment. Using this AxMBR process not only retains anaerobic ammonia oxidizing bacteria in the system but also maintains stable effluent quality, thus possessing the dual advantages of highly efficient nitrogen removal and stable process operation of anaerobic ammonia oxidation, solving the problem of limited application of anaerobic ammonia oxidation technology in domestic wastewater treatment. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a diagram of a wastewater treatment device according to an embodiment of the present invention.

[0030] Figure 2 This is a diagram showing the water output effect during the startup phase of an embodiment of the present invention.

[0031] Figure 3 This is a diagram showing the water output effect in stage I of an embodiment of the present invention.

[0032] Figure 4 This is a diagram showing the water output effect in stage II of the present invention.

[0033] Figure 5 This is a diagram showing the water output effect in stage III of this embodiment of the invention.

[0034] Figure 6 NH4 in the De-Anammox reactor of this invention + -N, NO2 - -N, NO3 - Graph showing the changes in influent and effluent concentrations of -N and TN.

[0035] Figure 7 This diagram illustrates the contribution of Anammox to nitrogen removal in stages S1 and S2 of this embodiment of the invention.

[0036] Figure 8 This is a graph showing the relative abundance variation of Anammox bacteria in an embodiment of the present invention.

[0037] In the diagram, 1. Inlet tank, 2. Anaerobic reactor, 3. MBR reactor, 4. Effluent tank, 5. Flow regulating valve, 6. Flow meter, 7. Anaerobic ammonia oxidizing bacteria packing, 8. Water distributor, 9. Activated carbon, 10. Agitator, 11. Effluent sedimentation tank, 12. Online pH monitoring system, 13. Alkali tank, 14. Baffle plate, 15. Liquid level controller, 16. Ceramic membrane module, 17. Backwash controller, 18. Solenoid valve, L1. Domestic sewage, L2. MBR reactor reflux liquid, L3. Anaerobic reactor effluent, L4. AxMBR system effluent, L5. Backwash inlet, L6. Backwash liquid, P1. Inlet pump, P2. Alkali pump, P3. Reflux pump, P4. Aeration pump, P5. Filter and backwash pump. Detailed Implementation

[0038] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0039] The following specific examples illustrate the embodiments disclosed in this invention. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. This invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments in this disclosure without creative effort are within the scope of protection of this disclosure.

[0040] In the start-up phase of this invention, the inoculated sludge was a mixed sludge from the CASS and anaerobic tanks of a municipal wastewater treatment plant, with inoculation volumes of 120 L each for anaerobic reactor 2 and MBR reactor 3. In Phase II, the inoculated sludge for the De-Anammox reactor consisted of successfully acclimated and highly active anaerobic ammonia oxidation granular sludge and anaerobic ammonia oxidation bacterial fiber balls, with inoculation volumes of 5 L and 0.1 m³, respectively. 3 The experimental water was campus domestic sewage, and its water quality and physicochemical properties are as follows: COD, 97.64-198.16 mg / L; TN, 55.97-73.58 mg / L; NH4+-N, 53.48-68.25 mg / L; NO2--N, 0-0.04 mg / L; NO3--N, 0-0.07 mg / L; DO, 0.04-0.15 mg / L; pH, 6.86-7.05; temperature, 17.9-26.4℃.

[0041] This invention employs the AxMBR process to treat domestic wastewater from a school in Guangxi. Figure 1 As shown, a wastewater treatment device based on anaerobic ammonia oxidation process includes:

[0042] The inlet tank 1 is used to store domestic sewage L1 to be treated; a flow regulating valve 5 and a flow meter 6 are provided between the inlet tank 1 and the anaerobic reactor 2; the domestic sewage L1 in the inlet tank 1 is pumped into the anaerobic reactor 2 through the inlet pump P1.

[0043] Anaerobic reactor 2, employing a De-Anammox reactor, is equipped with anaerobic ammonia-oxidizing bacteria packing material 7 and a stirrer 10. Anaerobic reactor 2 receives domestic wastewater L1 from influent tank 1 and uses the stirrer 10 to agitate the anaerobic ammonia-oxidizing bacteria packing material 7 for anaerobic reaction. Anaerobic reactor 2 also includes an online pH monitoring system 12 to measure the pH value of the liquid within the reactor 2, an alkali pump P2, and an alkali tank 13 for storing alkali. If the pH monitoring system 12 detects that the pH value of the liquid within the reactor 2 is outside a preset range, the alkali in the alkali tank 13 can be pumped into the reactor 2 as needed via the alkali pump P2. Activated carbon 9 is laid at the bottom of anaerobic reactor 2, and an effluent sedimentation tank 11 is provided on the inner wall of the reactor 2. The effluent L3 from the anaerobic reactor flows through the sedimentation tank 11 to the MBR reactor 3. A water distributor 8 is located at the bottom of anaerobic reactor 2.

[0044] MBR reactor 3 is used to receive the effluent L3 from the anaerobic reactor and carry out the MBR reaction. MBR reactor 3 includes an online pH monitoring system 12 and a return pump P3 to measure the pH value of the liquid inside the MBR reactor 3. When the online pH monitoring system 12 detects that the pH value of the liquid inside the MBR reactor 3 is not within a preset specified range, the return liquid L2 from the MBR reactor is pumped back by the return pump P3 and enters the anaerobic reactor 2 along with the domestic sewage L1. MBR reactor 3 also includes a baffle plate 14, a ceramic membrane module 16, a level controller 15, a backwash controller 17, an aeration pump P4, and a filtration / backwash pump P5. The baffle plate 14 and the ceramic membrane module 16 are installed inside the MBR reactor 3. Aeration pump P4 is connected to ceramic membrane module 16; the liquid in MBR reactor 3 treated by ceramic membrane module 16 is AxMBR system effluent L4. Filtering and backwashing pump P5 is used to pump AxMBR system effluent L4 into effluent tank 4 through solenoid valve 18, and also to backwash the liquid in effluent tank 4 back to MBR reactor 3 through backwash controller 17 and level controller 15. Figure 1 As shown, the liquid from the effluent tank is used as backwash influent L5 and as backwash liquid L6 to backwash back into the MBR reactor 3.

[0045] The AxMBR analysis device is used to perform AxMBR analysis on one or two selected anaerobic reactors (2 and 3) and MBR reactors (3), to cultivate successfully acclimatized and highly active anaerobic ammonia-oxidizing bacteria, obtain optimal temperature and dissolved oxygen (DO) concentration, and determine the microbial characteristics at the pilot-scale. AxMBR analysis includes routine index analysis, anaerobic reactor denitrification efficiency analysis, overall wastewater treatment plant microbial community structure analysis, effluent efficiency analysis at each stage, and anaerobic reactor denitrification efficiency and its correlation analysis. The stages include start-up and acclimatization, Stage I, Stage II, and Stage III.

[0046] Conventional index analysis included COD and NH4+ in the influent and effluent of the anaerobic reactor and MBR reactor at different stages.+ -N, NO2 - -N, NO3 - The concentrations of -N and TN were analyzed. COD was analyzed using a microwave-assisted closed digestion method with potassium dichromate; TN was analyzed using an alkaline potassium persulfate digestion method with ultraviolet spectrophotometry; NH4... + -N was analyzed using Nessler's reagent spectrophotometry; NO2 - -N was analyzed using the N-(1-neyl)-ethylenediamine spectrophotometric method; NO3 - -N was analyzed by UV-Vis spectrophotometry. pH and temperature were measured using a Beijing Tianjian online monitoring DEC digital pH meter DPH10AC; DO values ​​were measured using a Hach portable dissolved oxygen meter.

[0047] The nitrogen removal efficiency analysis of the anaerobic reactor includes the following steps: calculating the actual influent TN and NH4+ of the anaerobic reactor. + -N, NO2 - -N and NO3 - -N concentration, and then compared with TN and NH4 in the effluent of the anaerobic reactor. + -N, NO2 - -N and NO3 - The difference between -N concentrations is used to calculate the corresponding concentration change.

[0048] In stage II, a portion of NH4 in the MBR reactor + -N is oxidized to NO2 - -N is then returned to the De-Anammox reactor to react with NH4 in the influent. + -N is used as a substrate in the anaerobic ammonia oxidation reaction to remove nitrogen. The nitrogen removal efficiency of the De-Anammox reactor was analyzed, and the actual influent TN concentration I... TN The calculation formula is as follows: Unit: mg / L;

[0049] I TN : Actual influent TN concentration of the De-Anammox reactor; C TN TN concentration in campus domestic sewage. NO2 in campus domestic sewage influent. - -N and NO3 - The total amount of -N is low at 0.1 mg / L, therefore its TN content is mainly determined by NH4+. + -N content meter; R TN :TN concentration in the reflux solution of the MBR system; V C Campus domestic sewage inflow; V R MBR reactor reflux rate, V C ∶V R = 1:4.

[0050] I TN The simplified calculation formula is as follows:

[0051] Similarly, the actual influent NH4 in the De-Anammox reactor + -N, NO2 - -N, NO3 - -N concentration, as described above.

[0052] Actual influent TN and NH4 in the De-Anammox reactor + -N, NO2 - -N and NO3 - -N concentration, and then compared with TN and NH4 in the effluent from the De-Anammox reactor. + -N, NO2 - -N and NO3 - The concentration change can be determined by subtracting the -N concentration. Therefore, the NH4+ concentration changes in the De-Anammox reactor during stages II and III are... + The changes in -N concentration in the influent and effluent are as follows:

[0053] Unit: mg / L; ENH4 + -N:De-Anammox effluent NH4 + -N concentration.

[0054] Similarly, in the De-Anammox reactor, NO2 in stages II and III - -N, NO3 - The changes in influent and effluent concentrations of -N and TN are described above.

[0055] The AxMBR control device is used to control the environmental parameters of the anaerobic reactor and the MBR reactor based on the results of AxMBR analysis performed by the AxMBR analyzer.

[0056] The sludge samples used for microbial community structure analysis mainly included five types of sludge samples, as shown in Table 1. The samples were dehydrated and stored at -20°C. DNA was extracted from the sludge samples using the PowerSoil DNA Isolation Kit (Mo Bio, Carlsbad, CA, USA). Microbial sequencing was performed on the samples to analyze the diversity of the microbial community within the system. After verifying purity (OD260 / OD280 of 1.6-1.8), the DNA was amplified by polymerase chain reaction (PCR). PCR was used to amplify the target DNA fragments simultaneously with cleavage. The target DNA fragments were separated and purified by denaturing gradient gel electrophoresis (DGGE), in which DNA fragments from different microorganisms were immobilized at different positions on the gel. The sludge samples in this embodiment were sequenced by Shanghai Sangon Biotech Co., Ltd. (Shanghai, China), and BLAST analysis was used to compare the sequenced genes with the NCBI GenBank database.

[0057] Table 1. Sludge Sample Types and Sampling Stages:

[0058] sludge samples sludge sample types Corresponding stage A0 Sludge in the inlet pool AxMBR system startup B0 Anaerobic ammonia oxidizing bacteria Phase II Start C1-C3 MBR reactor packing sludge Phase I-III ended D1-D3 MBR reactor suspended sludge Phase I-III ended E1-E3 Anaerobic reactor suspended sludge Phase I-III ended

[0059] The analysis of water output performance at each stage includes the following steps:

[0060] Start-up and acclimatization phase (1-44 days): After adding anaerobic and aerobic mixed activated sludge, the hydraulic retention time (HRT) was gradually shortened from 48 hours to 8 hours, and the effluent results were as follows. Figure 2 As shown. When the effluent NH4 + When the -N concentration is below 5 mg / L and the effluent TN concentration is below 15 mg / L, the HRT is shortened to the next stage until the HRT = 8 h, at which point the effluent NH4+... + The -N concentration decreased from 30.48 mg / L to 10.05 mg / L, and the TN concentration in the effluent decreased from 33.5 mg / L to 18.53 mg / L, indicating that the AxMBR system was successfully started up and acclimatized, and the next stage of experiments can be carried out.

[0061] Phase I (1-21d): This stage represents the stable operation of the AxMBR system after successful startup, i.e., the nitrification-denitrification-MBR coupling, and its effluent conditions are as follows. Figure 3 As shown. The effluent COD concentration was maintained at 1.02-6.09 mg / L; the effluent NH4 concentration was... + -N concentration maintained between 2.22-4.64 mg / L; effluent NO2 - -N concentration maintained between 0.84-3.26 mg / L; effluent NO3 --N concentration was maintained at 6.60-8.85 mg / L; TN concentration in the effluent was maintained at 11.33-14.67 mg / L. These basic indicators all meet the Class A standard of the Discharge Standard of Pollutants for Urban Wastewater Treatment Plants (GB18918-2002).

[0062] Phase II (1-52 days): This phase involves the addition of laboratory-cultured, highly active anaerobic ammonia-oxidizing bacteria to the anaerobic reactor after Phase I, i.e., AxMBR coupling. The anaerobic reactor in this phase is called a De-Anammox reactor, and its effluent results are as follows... Figure 4 As shown. The COD concentration in the effluent from the AxMBR system was generally maintained below 6.40 mg / L; the NH4 concentration in the effluent was... + The nitrogen (N) concentration remained generally below 5.00 mg / L, and the total nitrogen (TN) concentration in the effluent remained generally below 14.87 mg / L. However, during the last week, due to the decrease in temperature, the anaerobic ammonia oxidation process weakened, and the concentrations of various indicators in the effluent increased somewhat, but still generally met the effluent standards. This fully demonstrates that the AxMBR coupling can resist changes in the external environment to a certain extent, and that the anaerobic ammonia oxidizing bacteria actively play a role in nitrogen removal.

[0063] Phase III (1-46 days): This phase involves increasing DO (dissolved oxygen) to ensure the effluent quality of the AxMBR system when the temperature drops below 25°C, essentially reverting to a nitrification-denitrification-MBR coupling operation. Figure 7 As can be seen, the effluent COD concentration remained between 1.54 and 7.03 mg / L, with an average concentration of 4.11 mg / L; the effluent NH4... + -N concentration remained between 1.22 and 4.20 mg / L, with an average concentration of 2.84 mg / L; effluent NO2 - -N concentration remained between 0.12 and 0.67 mg / L, with an average concentration of 0.29 mg / L; effluent NO3 - The -N concentration was maintained at 6.12-12.36 mg / L, with an average concentration of 9.49 mg / L; the TN concentration in the effluent was maintained at 10.08-14.93 mg / L, with an average concentration of 13.45 mg / L. Under these conditions, the effluent quality still met the effluent standards.

[0064] Dissolved oxygen (DO) is a crucial control parameter in all three stages. Adjusting the DO concentration helps the AxMBR system operate effectively under different temperature conditions and maintain good effluent quality. Collecting and analyzing DO data reveals that the optimal DO concentrations for the MBR reactor in different stages are: Stage I: 3.01 mg / L, Stage II: 2.29 mg / L, and Stage III: 2.73 mg / L. The average aeration rate for each stage is 1.34 m³ / L. 3 / h, 0.78m3 / h and 1.09m 3 Compared to stage I, the aeration rate in stages II and III decreased by approximately 41.0% and 18.0%, respectively. Under different operating conditions, the system consistently maintained a COD removal efficiency above 90%, and the effluent COD remained below 7 mg / L without significant decrease (e.g., ...). Figure 2 and Figure 5 This indicates that the system has good processing stability.

[0065] The denitrification effect of the anaerobic reactor and its correlation analysis include the analysis of the denitrification effect of the anaerobic reactor in stages II and III, and the contribution of Anammox and nitrification-denitrification to the denitrification of the AxMBR system under mesophilic conditions.

[0066] NH4 in Phase II and Phase III + -N, NO2 - -N, NO3 - The changes in influent and effluent concentrations of -N and TN as a percentage of the total changes are as follows: Figure 6 As shown, as the air temperature gradually decreases, the water temperature in the De-Anammox reactor drops from approximately 31°C in Stage II to approximately 25°C in Stage III. From Figure 6 As can be seen, the anaerobic ammonia oxidizing bacteria in stage II have high activity, and the combined action of nitrification-denitrification and anaerobic ammonia oxidation consumes NH4 in the wastewater. + -N, NO2 - -N and NO3 - -N. When the temperature decreases, firstly, the activity of anaerobic ammonia oxidizing bacteria weakens, leading to a reduction in anaerobic ammonia oxidation and denitrification in the reactor; secondly, when anaerobic ammonia oxidation decreases, the DO concentration in the MBR reactor needs to be increased to ensure effluent quality and promote nitrification and denitrification, which will increase the NO2 in the MBR reactor reflux. - The decrease in -N concentration leads to the limitation of anaerobic ammonia oxidation in the De-Anammox reactor. As time progresses, the denitrification effect of anaerobic ammonia oxidation in stage III will gradually decrease.

[0067] When the temperature is 23.2-26.1℃, the nitrogen removal contributions of anaerobic ammonium oxidation and nitrification-denitrification in the AxMBR system are as follows: Figure 7As shown (no other physicochemical denitrification methods were used in the biological denitrification process of campus domestic wastewater, so the denitrification process can be considered to involve only anaerobic ammonia oxidation and nitrification / denitrification). There was no significant change in ΔCTN between stages S1 and S2, with an average ΔCTN of 7.52 mg / L in stage S1 and 6.61 mg / L in stage S2, indicating that TN was effectively removed in both stages. ΔCxTN was significantly lower in stage S1 than in stage S2, with an average ΔCxTN of 1.78 mg / L in stage S1 and 5.40 mg / L in stage S2. According to the formula, the denitrification contribution of anaerobic ammonia oxidation in the De-Anammox reactor was slightly higher in stage S1 than in stage S2, with an average TNRR of 23.69% in stage S1 and 17.98% in stage S2. The reason for the lower TNRR in stage S1 is that the increased aeration rate in stage III reduced NO2 production in the MBR reactor. - -N, anaerobic ammonium oxidation activity decreases with decreasing temperature and substrate deficiency. Furthermore, over time, the content of anaerobic ammonium oxidizing bacteria in the MBR reflux becomes extremely low, and the traditional nitrification-denitrification sludge in the S2 stage plays a major role in nitrogen removal through denitrification. Therefore, when the temperature is 23.2-26.1℃, the nitrogen removal contribution of anaerobic ammonium oxidation in the AxMBR system is 17.98%, lower than the 82.02% contribution of nitrification-denitrification.

[0068] To better understand the changes in the relative abundance of denitrifying bacteria in the AxMBR system at different stages, this study conducted microbial analysis on species with a relative abundance greater than 1%. The results are as follows: Figure 8 As shown.

[0069] The aerobic and anaerobic activated sludge mixture (A0) from a conventional wastewater treatment plant, inoculated during AxMBR system startup, contained 1.22% nitrifying bacteria (Nitrospira), 0.96% denitrifying bacteria (Comamonas), and 1.81% Armatimonadetes_gp5, which is associated with anaerobic ammonia oxidation. Since B0 was a laboratory-screened and cultured strain, its anaerobic ammonia-oxidizing bacteria (Candidatus_Kuenenia and Candidatus_Brocadia) comprised 15.61% and 1.66% respectively, while Armatimonadetes_gp5, associated with anaerobic ammonia oxidation, accounted for 3.00%.

[0070] At the end of Stage I, the proportions of Nitrospira in the packing sludge (C1) and suspended sludge (D1) of the MBR reactor were 0.90% and 0.61%, respectively, a slight increase compared to the initial start-up period. In the sludge (E1) of the anaerobic reactor, the proportion of Commonas decreased from 0.96% to 0.18%, Dechloromonas increased from 0.10% to 2.89%, Thermomonas increased from 0.02% to 1.07%, and Ornatilinea, which has a synergistic denitrification effect, also increased from 0.09% to 1.93%. Based on these results, the denitrification capacity of the AxMBR system was significantly enhanced at the end of Stage I, reflecting that this AxMBR system can effectively screen for denitrifying bacteria.

[0071] At the end of Stage II, due to changes in the operating environment and the addition of new bacterial strains, the relative abundance of bacterial genera in the AxMBR system showed significant differences. Compared to C1, the proportion of Nitrospira in C2 increased from 0.9% to 2.10%, while in D2, compared to D1, the proportion of Nitrospira decreased from 0.61% to 0.26%, indicating that the addition of packing material was beneficial to the growth of Nitrospira in the MBR reactor. The proportions of denitrifying bacteria Dechloromonas and Thermomonas in C2 and D2 were significantly lower than those in C1 and D1, decreasing from 1.72% and 2.63% to 0.04% and 0.49%, respectively; and from 0.84% ​​and 0.85% to 0.06% and 0.12%, respectively. This indicates that the MBR reactor essentially did not perform denitrification in Stage II. The relative abundance of Candidatus_Kuenenia in the sludge of the De-Anammox reactor (E2) was 6.38%, which was 6% higher than the total abundance of denitrifying bacteria (Dechloromonas 0.66%, Commonas 0.06%, Thermomonas 0.11%). The relative abundance of Armatimonadetes_gp5, which is associated with anaerobic ammonium oxidation, also increased from 0.10% in E1 to 3.12%. This fully demonstrates that anaerobic ammonium oxidation is an important component of stage II denitrification.

[0072] At the end of Stage III, changes in temperature and dissolved oxygen (DO) caused further fluctuations in the relative abundance of bacterial genera in the AxMBR system. The relative abundance of *Nitrospira* in the MBR reactor remained relatively stable in C3, decreasing from 2.10% to 1.94%, while its relative abundance in D3 increased from 0.26% to 0.58%. Furthermore, the amount of suspended sludge in the MBR reactor was greater than that of the packing sludge, indicating a significant improvement in nitrification efficiency compared to the previous stage in Stage III. Simultaneously, the relative abundance of denitrifying bacteria in the MBR reactor also increased substantially. Specifically, the relative abundances of *Dechloromonas*, *Comamonas*, and *Thermomonas* increased from 0.04% and 0.49% in C2 and D2; 0.15% and 0.06% in C2 and D2; and 0.06% and 0.12% in D2 and C3, respectively, to 0.81% and 2.21% in C3 and D3; 0.65% and 1.39% in C3 and D3; and 0.59% and 1.10% in D3 and D3. The relative abundance of Ornatilinea, which has a synergistic denitrification effect, also increased from 0.13% and 0.51% in C2 and D2 to 0.23% and 0.63% in C3 and D3, respectively. In the De-Anammox reactor, the relative abundance of anaerobic ammonia oxidizing bacteria changed significantly during this period. The relative abundances of Candidatus_Kuenenia, Candidatus_Brocadia, and Armatimonadetes_gp5 decreased from 6.38%, 0.12%, and 3.12% in E2 to 0.07%, 0.00%, and 0.22% in E3, demonstrating that anaerobic ammonia oxidizing bacteria are essentially unable to survive in the AxMBR system when the temperature is below 15°C. Conversely, the relative abundance of denitrifying bacteria in the De-Anammox reactor increased significantly, with Dechloromonas, Commonas, and Thermomonas increasing from 0.66%, 0.06%, and 0.11% in E2 to 2.01%, 3.65%, and 1.95% in E3. This indicates that denitrification was fully realized in the De-Anammox reactor at the end of Stage III, and nitrogen removal in the AxMBR system at this point mainly relied on denitrification. Meanwhile, the increase in the proportion of denitrifying bacteria in the MBR reactor was primarily due to suspended sludge, which is likely because denitrifying bacteria from the De-Anammox reactor flowed into the MBR reactor with its effluent. It is worth noting that the microbiological results at the end of Stage III were obtained at temperatures below 15°C and do not necessarily indicate that anaerobic ammonia oxidation was completely absent from the nitrogen removal process in the AxMBR system during Stage III (temperatures above 15°C, especially above 20°C), i.e., the early or middle stages.

[0073] Furthermore, by observing the relative abundance changes of the bacterial community in all sludge samples, it was found that the relative abundance changes of the C1-C3 bacterial communities were the least, indicating that the packing material was least affected by temperature and DO changes, suggesting that the use of packing material is beneficial for maintaining the stability of the system.

[0074] Both the anaerobic reactor and the MBR reactor are cylindrical tanks with a diameter of 1.2m and an effective volume of 1.0m³. 3 .

[0075] The results obtained from the experiments and embodiments of the present invention are as follows:

[0076] (1) The AxMBR system can efficiently treat campus domestic sewage with relatively high nitrogen content. It can operate stably in different operating stages and the effluent quality basically meets the Class A standard of the Urban Wastewater Treatment Plant Pollutant Discharge Standard (GB18918-2002).

[0077] (2) Temperature and DO are important parameters that were optimized in different operating stages. The optimal operating temperature was above 27℃. When the temperature was 23.2-26.1℃, the nitrogen removal contributions of anaerobic ammonia oxidation and nitrification-denitrification in the AxMBR system were approximately 17.98% and 82.02%, respectively. The optimal DO concentrations for stages I-III were 3.01 mg / L, 2.29 mg / L, and 2.73 mg / L, respectively, with average aeration rates of 1.34 m³ / L and 1.34 m³ / L, respectively. 3 / h, 0.78m 3 / h and 1.09m 3 / h, the aeration rate of stage II and stage III decreased by approximately 41.0% and 18.0% respectively compared to stage I.

[0078] (3) The anaerobic ammonia oxidizing bacteria present in Stage II of the AxMBR system were Candidatus Kuenenia, with a relative abundance of 6.38% in E2, which is 6% higher than the total abundance of denitrifying bacteria (Dechloromonas 0.66%, Commonas 0.06%, Thermomonas 0.11%), indicating that anaerobic ammonia oxidation plays an important role in nitrogen removal in Stage II. The microbial community species, relative abundance, and diversity of the packing sludge showed the lowest variation, indicating that the use of packing material can help the AxMBR system operate stably.

[0079] The above provides a detailed description of a wastewater treatment device based on anaerobic ammonia oxidation process provided by the present invention. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A wastewater treatment device based on anaerobic ammonia oxidation process, characterized in that, include: The inlet tank is used to store domestic sewage awaiting treatment. The anaerobic reactor, employing the De-Anammox reactor design, is equipped with anaerobic ammonia-oxidizing bacteria packing material and a stirrer. The anaerobic reactor receives domestic sewage from the influent tank and uses the stirrer to agitate the anaerobic ammonia-oxidizing bacteria packing material for anaerobic reaction. The anaerobic reactor also includes an online pH monitoring system for measuring the pH value of the liquid within the reactor, an alkali pump, and an alkali tank for storing alkali. If the online pH monitoring system detects that the pH value of the liquid within the anaerobic reactor is outside a preset range, the alkali in the alkali tank can be pumped into the anaerobic reactor as needed. An MBR reactor is used to receive effluent from an anaerobic reactor and perform the MBR reaction. The MBR reactor includes an online pH monitoring system and a reflux pump to measure the pH value of the liquid within the reactor. If the online pH monitoring system detects that the pH value of the liquid within the MBR reactor is outside a preset range, the reflux liquid from the MBR reactor is pumped back and combined with domestic sewage into the anaerobic reactor. The MBR reactor also includes baffles, a ceramic membrane module, a level controller, a backwash controller, an aeration pump, and a filtration / backwash pump. The baffles and ceramic membrane module are installed inside the MBR reactor. The aeration pump is connected to the ceramic membrane module. The liquid in the MBR reactor treated by the ceramic membrane module is the effluent from the AxMBR system. The filtration / backwash pump is used to pump the effluent from the AxMBR system into an effluent tank and also to backwash the liquid from the effluent tank back into the MBR reactor via the backwash controller and the level controller. The AxMBR analysis device is used to perform AxMBR analysis on one or two specified types of anaerobic reactors and MBR reactors, to cultivate and acclimate anaerobic ammonia-oxidizing bacteria with successful and highly active culture, to obtain the optimal temperature and DO concentration, and to determine the microbial situation at the pilot scale. The AxMBR analysis includes conventional index analysis, denitrification effect analysis of the anaerobic reactor, microbial community structure analysis of the entire wastewater treatment device, effluent effect analysis at each stage, and denitrification effect and correlation analysis of the anaerobic reactor. The stages include the start-up and acclimatization stage, stage I, stage II, and stage III. The AxMBR control device is used to control the environmental parameters of the anaerobic reactor and the MBR reactor based on the results of AxMBR analysis performed by the AxMBR analyzer.

2. The wastewater treatment device based on anaerobic ammonia oxidation process according to claim 1, characterized in that, A flow regulating valve and a flow meter are installed between the inlet pool and the anaerobic reactor; domestic sewage in the inlet pool is pumped into the anaerobic reactor by an inlet pump.

3. A wastewater treatment device based on anaerobic ammonia oxidation process according to claim 1, characterized in that, Both the anaerobic reactor and the MBR reactor are cylindrical tanks with a diameter of 1.2m and an effective volume of 1.0m³. 3 .

4. A wastewater treatment device based on anaerobic ammonia oxidation process according to claim 1, characterized in that, The bottom of the anaerobic reactor is lined with activated carbon, and the inner wall of the anaerobic reactor is provided with an effluent sedimentation tank. The effluent from the anaerobic reactor is then fed into the MBR reactor through the effluent sedimentation tank.

5. A wastewater treatment device based on anaerobic ammonia oxidation process according to claim 1, characterized in that, Conventional index analysis includes COD and NH4 in the influent and effluent of anaerobic reactors and MBR reactors at different stages. + -N, NO2 - -N, NO3 - The concentrations of -N and TN were analyzed. COD was analyzed using a microwave-assisted closed digestion method with potassium dichromate; TN was analyzed using an alkaline potassium persulfate digestion method with ultraviolet spectrophotometry; NH4... + -N was analyzed using Nessler's reagent spectrophotometry; NO2 - -N was analyzed using the N-(1-naphthyl)-ethylenediamine spectrophotometric method; NO3 - -N analysis by UV-Vis spectrophotometry.

6. A wastewater treatment device based on anaerobic ammonia oxidation process according to claim 1, characterized in that, The nitrogen removal efficiency analysis of the anaerobic reactor includes the following steps: calculating the actual influent TN and NH4+ of the anaerobic reactor. + -N, NO2 - -N and NO3 - -N concentration, and then compared with TN and NH4 in the effluent of the anaerobic reactor. + -N, NO2 - -N and NO3 - The difference between -N concentrations is used to calculate the corresponding concentration change.

7. A wastewater treatment device based on anaerobic ammonia oxidation process according to claim 1, characterized in that, The microbial community structure of the entire wastewater treatment device was analyzed by collecting sludge samples of the specified sludge sample type according to the corresponding stage; the sludge samples were dehydrated and stored in a -20°C freezer; DNA was extracted from the sludge samples using the PowerSoil DNA Separation Kit and microbial sequencing was performed on the sludge samples to analyze the diversity of the microbial community within the system. After verifying the purity, the DNA was amplified by polymerase chain reaction; the target DNA fragment was amplified simultaneously with PCR cutting; the target DNA fragment was separated and purified by denaturing gradient gel electrophoresis, in which DNA fragments of different microorganisms were fixed at different positions on the gel.

8. A wastewater treatment device based on anaerobic ammonia oxidation process according to claim 1, characterized in that, The sludge sample types include influent sludge, anaerobic ammonia oxidizing bacteria, MBR reactor packing sludge, MBR reactor suspended sludge, and anaerobic reactor suspended sludge.

9. A wastewater treatment device based on anaerobic ammonia oxidation process according to claim 1, characterized in that, The analysis of water output performance at each stage includes the following steps: Initial acclimatization phase: After adding anaerobic and aerobic mixed activated sludge, the hydraulic retention time (HRT) is gradually shortened from 48 hours to 8 hours; when the effluent NH4... + When the -N concentration is below 5 mg / L and the effluent TN concentration is below 15 mg / L, the HRT is shortened to the next stage until the HRT = 8 h, at which point the effluent NH4+... + The concentration of -N decreased from 30.48 mg / L to 10.05 mg / L, and the concentration of TN in the effluent decreased from 33.5 mg / L to 18.53 mg / L, indicating that the AxMBR system was successfully started up and acclimatized, and the next stage of experiments can be carried out. Phase I: This refers to the stable operation of the AxMBR system after successful startup, i.e., nitrification-denitrification-MBR coupling; effluent COD concentration maintained at 1.02-6.09 mg / L; effluent NH4... + -N concentration maintained between 2.22-4.64 mg / L; effluent NO2 - -N concentration maintained between 0.84-3.26 mg / L; effluent NO3 - -N concentration was maintained at 6.60-8.85 mg / L; effluent TN concentration was maintained at 11.33-14.67 mg / L; Phase II: This phase involves the addition of laboratory-cultured, highly active anaerobic ammonia-oxidizing bacteria to the anaerobic reactor after Phase I, i.e., AxMBR coupling; the overall COD concentration in the AxMBR system effluent remains below 6.40 mg / L; the effluent NH4... + -N concentration was generally maintained below 5.00 mg / L, and TN concentration in the effluent was generally maintained below 14.87 mg / L; Phase III: This phase involves increasing DO (dissolved oxygen) to maintain the effluent quality of the AxMBR system when the temperature drops below 25℃, essentially restoring the nitrification-denitrification-MBR coupling. The effluent COD concentration is maintained between 1.54-7.03 mg / L, with an average concentration of 4.11 mg / L; the effluent NH4... + -N concentration remained between 1.22 and 4.20 mg / L, with an average concentration of 2.84 mg / L; effluent NO2 - -N concentration remained between 0.12 and 0.67 mg / L, with an average concentration of 0.29 mg / L; effluent NO3 - -N concentration was maintained at 6.12-12.36 mg / L, with an average concentration of 9.49 mg / L; TN concentration in the effluent was maintained at 10.08-14.93 mg / L, with an average concentration of 13.45 mg / L.

10. A wastewater treatment device based on anaerobic ammonia oxidation process according to claim 1, characterized in that, The denitrification effect of the anaerobic reactor and its correlation analysis include the analysis of the denitrification effect of the anaerobic reactor in stages II and III, and the contribution of Anammox and nitrification-denitrification to the denitrification of the AxMBR system under mesophilic conditions.

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