A method for flue gas denitration by anaerobic ammonia oxidation with nitrite strengthening

Abstract

The application discloses a method for strengthening flue gas denitrification of anaerobic ammonia oxidation by nitrite, and belongs to the field of anaerobic ammonia oxidation process. + -N, NO2 ‑ -N and NO3 ‑ -N concentration change, calculates the denitrification rate, and determines the optimal NO2 ‑ -N / NH4 + -N molar ratio; the simulated wastewater is placed in a biological trickling filter tower for reaction; finally, the reactor is closed, precipitation is carried out, water samples are extracted, and NO2 ‑ -N / NH4 + -N=0.25, and under the condition that the NO concentration is 1000ppm, the denitrification rate of anaerobic ammonia oxidation can be improved. The method improves the stability and activity of the microbial community in the system, finally improves the overall performance of flue gas denitrification of anaerobic ammonia oxidation, enhances the ability of the system to cope with actual complex flue gas environment, and provides a more feasible and efficient technical scheme for engineering application of flue gas denitrification technology.

Description

Technical Field

[0001] This invention relates to the field of anaerobic ammonia oxidation processes, and more specifically to a method for enhancing anaerobic ammonia oxidation flue gas denitrification using nitrite. Background Technology

[0002] NO, a key nitrogen pollutant in the atmosphere, requires efficient removal to improve air quality. Traditional biological denitrification technologies (such as nitrification-denitrification) are insufficient to meet the demands of green and low-carbon development due to carbon source dependence and greenhouse gas emissions. Anammox, a novel treatment process, does not require an external carbon source. The core mechanism of traditional anammox flue gas denitrification technology is the conversion of NH3 and NO into the intermediate product hydrazine (N2H4) through the metabolic activity of AnAOB and the use of NO as an electron acceptor in the flue gas. Subsequently, N2H4 is further decomposed into nitrogen (N2) under the catalysis of HZS, ultimately achieving efficient removal of NO from the flue gas. This process does not require the addition of exogenous organic carbon matrix and does not emit greenhouse gases, meeting the requirements of green denitrification. However, in practical engineering, the reduction of NO to N2H4 requires a large amount of energy, which limits the metabolic activity of the microbial community. High concentrations of NO also inhibit the core bottleneck of AnAOB, mainly manifested as a decrease in denitrification rate caused by the decline in AnAOB activity and the risk of system instability.

[0003] In anaerobic ammonia oxidation metabolic systems, NO2 - It can also serve as a key electron acceptor for anaerobic ammonia-oxidizing bacteria. However, in flue gas denitrification applications, NO2... - Insufficient supply often leads to limited electron acceptors, significantly inhibiting denitrification performance. Studies have shown that exogenous NO2 supplementation... - The nitrogen metabolism pathway can be activated by upregulating the expression of AnAOB functional genes. Based on this, the activity of the nitrogen metabolism pathway can be activated by regulating NO2. - The dosage is adjusted to maintain the activity of AnAOB while ensuring the stable denitrification efficiency of the system.

[0004] Traditional anaerobic ammonium oxidation processes operate under anaerobic conditions, using NH4+. + -N and NO2 - Nitrogen oxides are converted into N2 and released into the atmosphere through the metabolism of specific microorganisms called AnAOB. ​​However, high concentrations of substrate may be toxic to AnAOB, while low concentrations may limit its biomass growth.

[0005] In the prior art, a low-carbon device and method based on anaerobic ammonia oxidation and synergistic deammoniation and denitrification is disclosed in patent number CN202410770261.5. In this patent, NO in the low-carbon device diffuses directly into the liquid phase in the form of bubble-free aeration, and then the anaerobic ammonia oxidizing bacteria in the reaction system can deammonia nitrogen (NH4) in the liquid phase. + The conversion of NO to N2 optimizes the process flow and improves operating efficiency. Although this process enables the direct utilization of NO by anaerobic ammonia oxidizing bacteria, it is limited by problems such as low NO mass transfer efficiency, susceptibility of bacterial communities to toxicity inhibition, and insufficient multi-factor synergistic optimization, making it difficult to cope with high concentration fluctuations of NO in industrial flue gas and complex environments.

[0006] The patent CN201610815205.4 describes a biological denitrification method using anaerobic ammonia oxidizing bacteria. This patent involves inoculating anaerobic ammonia oxidizing bacteria into an anaerobic ammonia oxidation reactor, adding a substrate reaction solution, and introducing NO-containing gas into the reactor as bubbles through an aerator at the bottom. These NO-containing bubbles collide with the anaerobic ammonia oxidizing bacteria as they pass through the bacterial solution, acting as agitators. During this process, the anaerobic ammonia oxidizing bacteria and bubbles directly capture NO from the gas, using it as an electron acceptor and ammonia nitrogen from the substrate solution as an electrochemical donor, thus completing the anaerobic ammonia oxidation process and converting NO and ammonia nitrogen into nitrogen gas, which is then discharged from the reactor. This invention uses a bottom aerator to continuously introduce NO into the reactor as bubbles. However, NO is not a common industrial raw material, and its preparation and purification processes are complex, thus increasing equipment investment and operating costs.

[0007] The two patents mentioned above have solved some of the problems in anaerobic ammonia oxidation, but are still limited by issues such as bacterial toxicity, cost of exogenous reagents, and safety risks. Summary of the Invention

[0008] To address the problem that high concentrations of NO inhibit the activity of AnAOB, leading to a decrease in its activity, biomass, and abundance, the present invention aims to provide a method for enhancing anaerobic ammonium oxidation flue gas denitrification using nitrite.

[0009] The objective of this invention is achieved through the following technical solution: a method for enhanced anaerobic ammonia oxidation flue gas denitrification using nitrite, comprising:

[0010] S1. Activate the microbial strain to obtain acclimatized anaerobic ammonia oxidation sludge from the Sequencing Batch Reactor (SBR) until the specific activity is ≥900 mg-N / (L). 2 •d) Carrier modification: Immerse the high-porosity porous carrier in concentrated sludge within a concentration range that ensures the pre-attachment effect of the biofilm, and let it stand until the pre-attachment of the biofilm is completed.

[0011] S2. Prepare simulated wastewater, wherein the simulated wastewater contains nitrogen ions, phosphorus ions, bicarbonate ions and trace elements, wherein the nitrogen ions include ammonium ions and nitrite ions.

[0012] S3. After inoculating the anaerobic ammonia oxidation sludge into the container, simulated wastewater is injected. Dissolved oxygen (DO) is maintained at ≤0.1 mg / L by N2 stripping. NO gas of different preset concentrations is introduced in batches. Water samples are taken periodically, filtered through a filter membrane, and NH4 is measured. + -N, NO2 - -N and NO3 - The -N index is used to calculate the denitrification rate in order to determine the optimal NO2 concentration. - -N / NH4 + -N molar ratio;

[0013] S4. In the reactor, the optimal NO2 - -N / NH4 + Simulated wastewater with a N-to-substrate molar ratio concentration was placed in a circulating water tank for spraying to enhance biofilm formation; N2 and NO were mixed evenly and then introduced into the reactor.

[0014] S5. Shut down the reactor, allow sedimentation, and extract water samples through the sampling port.

[0015] Furthermore, the MLSS of the anammox sludge is 12.5 g / L, and the MLVSS / MLSS ratio is 0.65; the MLSS of the concentrated sludge is ≥4.0 g / L.

[0016] Furthermore, the container is a 500ml serum bottle.

[0017] Furthermore, the different preset concentrations of NO gas are 300, 500, 1000, and 2000 ppm.

[0018] Furthermore, the membrane filtration includes sequential filtration through 0.45μm and 0.22μm membranes.

[0019] Furthermore, the optimal NO2 - -N / NH4 + The -N molar ratio is 0.25.

[0020] Furthermore, the reactor is a bio-trickling filter (BTF).

[0021] Furthermore, the temperature of the circulating water tank is 35±0.5℃, and the pH is 7.6-7.8.

[0022] Furthermore, the step of preparing N2 and NO in a certain proportion and then mixing them evenly before introducing them into the reactor includes: adjusting the flow rate of the mixed gas through a mass flow controller and adding it to a mixing tank for uniform mixing.

[0023] The present invention also provides an apparatus for enhancing anaerobic ammonia oxidation flue gas denitrification using nitrite, comprising: NO gas cylinder, N2 gas cylinder, mass flow meter, gas mixing tank, circulating water tank, peristaltic pump, anaerobic ammonia oxidation reactor, and tail gas collection device;

[0024] The NO and N2 gas cylinders are connected to the inlet of the gas mixing tank via gas pipelines equipped with mass flow meters. The outlet of the gas mixing tank is connected in parallel to the bottom inlets of the two anaerobic ammonia oxidation reactors via gas pipelines equipped with mass flow meters. The lower liquid distribution ports of the two anaerobic ammonia oxidation reactors are connected to two circulating water tanks via liquid pipelines equipped with peristaltic pumps. The top outlets of the two anaerobic ammonia oxidation reactors are connected to two tail gas collection devices via gas pipelines.

[0025] The beneficial effects of this invention are as follows: Based on the key role of nitrite in the Anammox system and the influence mechanism of NO on AnAOB, this invention studies different NO2... - -N / NH4 + The effects of -N molar ratio and NO concentration on the denitrification performance of Anammox were investigated; a BTF system was also constructed to study the effects of NO2 addition. - The impact of long-term operation on denitrification efficiency. Based on the above research, a method was developed to improve the denitrification efficiency and system stability of anaerobic ammonia oxidation flue gas using nitrite. NO2 was determined. - -N / NH4 + When -N = 0.25, the denitrification rate of anaerobic ammonia oxidation can be increased under NO concentration of 1000 ppm. During long-term operation of the biotrickling filter system, this ratio can stabilize the abundance above 15%, with a counter-trend increase in the abundance of core functional bacteria genera, improving the stability and activity of the microbial community in the system. Ultimately, this enhances the overall performance of anaerobic ammonia oxidation flue gas denitrification, strengthens the system's ability to cope with complex flue gas environments, and provides a more feasible and efficient technical solution for the engineering application of flue gas denitrification technology. Furthermore, the method of this invention does not require expensive catalysts, resulting in low operating and maintenance costs; it avoids ammonia escape, reducing secondary pollution; and it can operate stably under low temperature or high load conditions. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the device of the present invention;

[0027] Figure 2 For different NO concentrations and NO2 - -N / NH4 + Schematic diagram showing the effect of -N ratio on TN removal performance;

[0028] Figure 3 Schematic diagram of long-term operation results of anaerobic ammonia oxidation reactor for NO removal;

[0029] Figure 4 A schematic diagram showing the relative abundance of the genus Candidatus Brocadia (AnAOB).

[0030] In the diagram, NO cylinder 1, N2 cylinder 2, mass flow meter 3, gas mixing tank 4, circulating water tank 5, peristaltic pump 6, anaerobic ammonia oxidation reactor 7, and tail gas collection device 8. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art should fall within the protection scope of the embodiments of this application.

[0032] like Figure 1 As shown, this embodiment of the invention provides an apparatus for enhancing an anaerobic ammonia oxidation system using nitrite, including an NO gas cylinder 1, an N2 gas cylinder 2, a mass flow meter 3, a gas mixing tank 4, a circulating water tank 5, a peristaltic pump 6, an anaerobic ammonia oxidation reactor 7, and a tail gas collection device 8.

[0033] The NO gas cylinder 1 and N2 gas cylinder 2 are respectively connected to the inlet of the gas mixing tank 4 through gas pipelines equipped with mass flow meters 3; the outlet of the gas mixing tank 4 is connected in parallel to the bottom inlet of the two anaerobic ammonia oxidation reactors 7 through gas pipelines equipped with mass flow meters 3; the lower liquid distribution ports of the two anaerobic ammonia oxidation reactors 7 are respectively connected to the two circulating water tanks 5 through liquid pipelines equipped with peristaltic pumps 6 to form a circulation; the top outlets of the two anaerobic ammonia oxidation reactors 7 are respectively connected to the two tail gas collection devices 8 through gas pipelines.

[0034] Based on the above-described apparatus, this invention provides a method for enhanced anaerobic ammonia oxidation flue gas denitrification using nitrite, comprising the following steps:

[0035] (1) Microbial culture and carrier pretreatment: First, the strain was activated by taking anaerobic ammonia oxidation sludge (MLSS = 12.5 g / L, MLVSS / MLSS = 0.65) that had been acclimated for a long time in a laboratory-operated sequencing batch reactor (SBR) until the specific activity was ≥900 mg-N / (L). 2 ·d)). Next, the carrier was modified by immersing polyurethane sponge (20×20×20mm, porosity ≥95%) in concentrated sludge (MLSS≥4.0g / L) and allowing it to stand at 35℃ for 6 hours to complete the pre-attachment of biofilm.

[0036] (2) Preparation of simulated wastewater: NH4Cl and NaNO2 are used as nitrogen sources, KH2PO4 is used as phosphorus source, NaHCO3 is used as buffer, and trace elements are added to prepare simulated wastewater.

[0037] (3) Batch Experiment: A 500mL serum bottle was used as the reactor. After inoculating an equal amount of Anammox sludge, simulated wastewater was injected. Dissolved oxygen (DO) was maintained at ≤0.1mg / L by N2 stripping. Subsequently, 400mL of NO gas at concentrations of 300, 500, 1000, and 2000ppm was introduced in batches. NH4 was then detected. + -N, NO2 - -N and NO3 - By analyzing the change in NO2- concentration, the denitrification rate can be calculated to determine the optimal NO2 concentration. - -N addition amount (NO2) - -N / NH4 + -N molar ratio).

[0038] (4) Reactor Operation: A biotrickling filter (BTF) reactor was used. The final specific concentration of substrate (NH4) was then transferred to the reactor. + -N and NO2 - Simulated wastewater containing nitrogen (N2) is placed in a circulating water tank and sprayed (35±0.5℃, pH 7.6-7.8) to enhance biofilm formation. The mixed gas is prepared by mixing N2 and NO in a certain proportion, and after the flow rate is adjusted by a mass flow controller, it enters the mixing tank for uniform mixing, and then enters the reactor through the bottom inlet of the BTF.

[0039] (5) Sampling: Close the reactor, allow sedimentation, and extract water samples through the sampling port.

[0040] Example 1: NO2 - -N / NH4 + -N dosage ratio

[0041] (1) Microbial culture and carrier pretreatment: First, the strain was activated by taking anaerobic ammonia oxidation sludge (MLSS = 12.5 g / L, MLVSS / MLSS = 0.65) that had been acclimatized for a long time in a sequencing batch reactor operated in the laboratory, until the specific activity was ≥900 mg-N / (L). 2 ·d)). Next, the carrier was modified by immersing polyurethane sponge (20×20×20mm, porosity ≥95%) in concentrated sludge (MLSS≥4.0g / L) and letting it stand at 35℃ for 6 hours to complete the pre-attachment of biofilm.

[0042] (2) Preparation of simulated wastewater: NH4Cl and NaNO2 are used as nitrogen sources, KH2PO4 is used as phosphorus source, NaHCO3 is used as buffer, and trace elements are added to prepare simulated wastewater.

[0043] The simulated wastewater contained 60 mg / L of ammonium chloride (NH4Cl) and 60 mg / L of sodium nitrite (NaNO2) according to the specified ratio. - -N / NH4 + -N=1), 30mg / L (NO2) - -N / NH4 + -N=0.5), 15mg / L (NO2) - -N / NH4 + -N=0.25) and 0 mg / L (NO2) - -N / NH4 + -N=0), sodium bicarbonate (NaHCO3) 100mg / L, potassium dihydrogen phosphate (KH2PO4) 20mg / L, calcium chloride (CaCl2) 100mg / L, trace element solution A 1mL / L and trace element solution B 1mL / L.

[0044] The components of trace element A solution are as follows: ferric sulfate (FeSO4·7H2O) 55000 mg / L and ethylenediaminetetraacetic acid (EDTA) 5000 mg / L.

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

[0046] (3) Batch experiment: The experiment used a 500mL serum bottle as a reactor. After inoculating an equal amount of Anammox sludge, simulated wastewater was injected. The dissolved oxygen (DO) was ≤0.1mg / L by N2 stripping, and then 400mL of NO gas of a preset concentration was introduced.

[0047] (4) Sampling: Water samples were collected using a sterile disposable syringe, with samples taken at regular intervals and in quantitative amounts through the pre-reserved sampling port. Specifically, 5 mL samples were taken at 0, 0.5, 1, 2, and 3 hours to calculate the denitrification rate and determine the optimal NO2 concentration. - -N addition amount (NO2) - -N / NH4 + -N molar ratio).

[0048] (5) Measurement of different NO2 - -N / NH4 + NH4+ in the effluent from the -N proportioning reactor+ -N, NO2 - -N and NO3 - -N. In different NO2 - -N / NH4 + Under -N molar ratio conditions, TN removal efficiency and NO2 - -N concentration showed a positive correlation, indicating that high NO2 concentrations - -N dominates the denitrification process by promoting the classical Anammox metabolic pathway. This involves comparing different NO concentrations and NO2... - -N / NH4 + The effect of -N molar ratio, such as Figure 2 As shown, when NO is 1000 ppm, NO2 - -N / NH4 + The TN removal rate was optimal when the -N molar ratio was 0.25. This phenomenon is highly coupled with the upregulation of NO2 expression in the metagenomics. Studies have found that NO2... - The addition of -N enhances denitrification through a dual mechanism: firstly, it directly participates in the Anammox reaction as an electron acceptor; secondly, it activates narG→NO2. - The reduction pathway promotes the conversion of NO to N2. Therefore, NO2 is identified as... - -N / NH4 + A NO2 molar ratio of 0.25 is the most economically efficient. - -N addition ratio, i.e., NO2 - -N / NH4 + -N = 0.25.

[0049] Example 2: Long-term operational stability verification

[0050] (1) Microbial culture and carrier pretreatment: First, the strain was activated by taking anaerobic ammonia oxidation sludge (MLSS = 12.5 g / L, MLVSS / MLSS = 0.65) that had been acclimated for a long time in a laboratory-operated sequencing batch reactor (SBR) until the specific activity was ≥900 mg-N / (L). 2 ·d)). Next, the carrier was modified by immersing polyurethane sponge (20×20×20mm, porosity ≥95%) in concentrated sludge (MLSS≥4.0g / L) and letting it stand at 35℃ for 6 hours to complete the pre-attachment of biofilm.

[0051] (2) Preparation of simulated wastewater: NH4Cl and NaNO2 are used as nitrogen sources, KH2PO4 is used as phosphorus source, NaHCO3 is used as buffer, and trace elements are added to prepare simulated wastewater.

[0052] The simulated wastewater contained 60 mg / L of ammonium chloride (NH4Cl), 15 mg / L of sodium nitrite (NaNO2), 100 mg / L of sodium bicarbonate (NaHCO3), 20 mg / L of potassium dihydrogen phosphate (KH2PO4), 100 mg / L of calcium chloride (CaCl2), 1 mL / L of trace element A solution, and 1 mL / L of trace element B solution.

[0053] The components of trace element A solution are as follows: ferric sulfate (FeSO4·7H2O) 55000 mg / L and ethylenediaminetetraacetic acid (EDTA) 5000 mg / L.

[0054] The composition of trace element B solution is as follows: ethylenediaminetetraacetic acid (EDTA) 15000 mg / L, zinc sulfate (ZnSO4·7H2O) 430 mg / L, cobalt chloride (CoCl2·6H2O) 240 mg / L, manganese chloride (MnCl2·4H2O) 990 mg / L, nickel chloride (NiCl2·6H2O) 190 mg / L, copper sulfate (CuSO4·5H2O) 250 mg / L, sodium molybdate (Na2MoO4·2H2O) 220 mg / L, boric acid (H3BO3) 14 mg / L, and sodium selenate (NaSeO4·10H2O) 210 mg / L.

[0055] (3) Reactor Operation: A biotrickling filter (BTF) reactor was used. The final specific concentration of substrate (NH4) was then introduced. + -N and NO2 - Simulated wastewater containing NO2 (NO2-N) was placed in a circulating water tank and sprayed (35±0.5℃, pH 7.6-7.8) to enhance biofilm formation. Two parallel Anammox-BTF systems were designed for comparative experiments: NO2 - Enhanced Group (BTF1): Influent contains exogenous NO2 - -N(15mg / L, NO2) - -N / NH4 + -N=0.25); Control group (BTF2): No exogenous NO2 - -N is added. The influent is simulated wastewater, and the reaction temperature is maintained by a constant temperature water bath (35±1℃). The mixed gas is prepared by N2 and NO in proportion, and after the flow rate is adjusted by a mass flow controller, it enters the mixing tank for uniform mixing (NO gas concentration 500ppm, gas flow rate 1.2L / min), and then enters the reactor through the bottom inlet of the BTF.

[0056] (4) The experiment lasted for 25 days, during which biomass dynamics (MLSS, MLVSS) were monitored weekly, and a total of 6 periodic samplings were completed. In addition, sludge samples were collected on day 0 (initial sludge sample 1) and day 25 (BTF1 sample 2, BTF2 sample 3). After 24 days of continuous operation, the NO concentration at the vent showed a trend of first decreasing and then stabilizing. Specifically, NO2... - The NO removal efficiency of the enhanced group (BTF1) was higher than that of the control group (BTF2), such as Figure 3 As shown. Furthermore, metagenomic sequencing was used to analyze the evolutionary patterns of microbial community structure and functional genes. Among them, the relative abundance of *Candidatus Brocadia* (AnAOB) in the nitrite-added group remained consistently above 15%, higher than the other two groups, such as... Figure 4 As shown, this confirms NO2 - The addition of [a substance] enhances the metabolic activity of anaerobic ammonia-oxidizing bacteria, improves denitrification efficiency, and maintains system stability.

[0057] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only.

[0058] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A method for enhanced anaerobic ammonium oxidation flue gas denitrification using nitrite, characterized in that, Includes the following steps: S1. Activate the bacterial strain to obtain anaerobic ammonia oxidation sludge acclimated in a sequencing batch reactor until the specific activity is ≥900 mg-N / (L²·d); modify the carrier by immersing a high-porosity porous carrier in the concentrated sludge and allowing it to stand at 35°C for 6 hours to complete biofilm pre-attachment; wherein, the MLSS of the anaerobic ammonia oxidation sludge is 12.5 g / L, and the MLVSS / MLSS is 0.65; the MLSS of the concentrated sludge is ≥4.0 g / L; the high-porosity porous carrier is a polyurethane sponge with a porosity ≥95%; S2. Prepare simulated wastewater, wherein the simulated wastewater contains nitrogen ions, phosphorus ions, bicarbonate ions and trace elements, wherein the nitrogen ions include ammonium ions and nitrite ions. S3. After inoculating the anaerobic ammonia oxidation sludge into the container, simulated wastewater is injected. Dissolved oxygen (DO) is maintained at ≤0.1 mg / L by N2 stripping. NO gas of different preset concentrations is introduced in batches. Water samples are taken periodically, filtered through a filter membrane, and NH4 is measured. + -N, NO2 - -N and NO3 - The -N index is used to calculate the denitrification rate in order to determine the optimal NO2 concentration. - -N / NH4 + -N molar ratio; when NO is 1000ppm, NO2 - -N / NH4 + The NO removal rate showed the best performance when the -N molar ratio was 0.

25. S4. In the reactor, the optimal NO2 - -N / NH4 + Simulated wastewater with a substrate concentration of -N molar ratio was placed in a circulating water tank for spraying to enhance biofilm formation; N2 and NO were uniformly mixed and introduced into the reactor; the reactor was a biotrickling filter (BTF). S5. Shut down the reactor, allow sedimentation, and extract water samples through the sampling port.

2. The method according to claim 1, characterized in that, The container used is a 500ml serum bottle.

3. The method according to claim 1, characterized in that, The different preset concentrations of NO gas are 300, 500, 1000, and 2000 ppm.

4. The method according to claim 1, characterized in that, The membrane filtration process includes sequential filtration through 0.45μm and 0.22μm membranes.

5. The method according to claim 1, characterized in that, The temperature of the circulating water tank is 35±0.5℃, and the pH is 7.6-7.

8.

6. The method according to claim 1, characterized in that, The step of preparing N2 and NO in a certain proportion and then mixing them evenly before introducing them into the reactor includes: adjusting the flow rate of the mixed gas through a mass flow controller and adding it to a mixing tank for uniform mixing.

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