Aerobic denitrifying bacterium and application thereof

Abstract

The invention relates to the technical field of sewage treatment, in particular to aerobic denitrifying bacteria and application thereof. The bacterial strain is monomonas stutzeri C3, the bacterial strain is preserved in Guangdong Microbiological Culture Collection Center, the preservation number is GDMCC No.66733, and the 16S rDNA sequence of the bacterial strain is as shown in SEQ ID NO.1. The invention further discloses a preparation method of the bacterial strain. The invention relates to application of aerobic denitrifying bacteria in sewage treatment, in particular to application in treatment of sewage of a stainless steel plant. The strain disclosed by the invention is used for carrying out denitrification treatment on sewage in an aerobic environment, and nitrate nitrogen, nitrate nitrogen and COD (Chemical Oxygen Demand) in the sewage can be efficiently removed.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to an aerobic denitrifying bacterium and its application. Background Technology

[0002] Excessive nitrogen in wastewater (such as feces in domestic sewage and nitrogenous organic matter in industrial wastewater) can lead to eutrophication (e.g., cyanobacterial blooms). The core function of aerobic denitrifying bacteria is to convert nitrates / nitrites produced in wastewater through pretreatment (such as nitrification) into harmless nitrogen gas, thus completely removing nitrogen. However, existing aerobic denitrifying bacteria have insufficient nitrogen degradation rates. For example, CN103667168A discloses an aerobic denitrifying bacterium and its application in wastewater treatment. This aerobic denitrifying bacterium belongs to *Pseudomonas stearothermii*, and after 24 hours, it can achieve a nitrate nitrogen removal rate of 99.6% and a denitrification rate of 22.6 mg / L. -1 •h -1 For example, CN114806919A discloses a highly efficient aerobic denitrifying strain and its application. This aerobic denitrifying strain belongs to the genus Aeromonas, and under optimal conditions, the nitrate removal rate reaches 95.57% after 24 hours, corresponding to a nitrate removal rate of 14.62 mg / L•h. Furthermore, existing aerobic denitrifying bacteria do not completely remove nitrate; for instance, CN103667168A shows a nitrate removal rate of 99.6% after 24 hours, with a small amount remaining.

[0003] Therefore, it is necessary to provide an aerobic denitrifying bacterium with a high nitrate removal rate and complete nitrate removal to achieve excellent wastewater treatment results. Summary of the Invention

[0004] The purpose of this invention is to propose an aerobic denitrifying bacterium and its application. This strain can denitrify wastewater in an aerobic environment and efficiently remove nitrate nitrogen, COD and other pollutants from the wastewater.

[0005] To achieve this objective, the present invention adopts the following technical solution: An aerobic denitrifying bacterium, strain C3, classified as *Stutzerimonasstutzeri*, is deposited at the Guangdong Provincial Center for Microbial Culture Collection (GDMCC) with accession number GDMCC No. 66733, date of deposit: July 23, 2025, address of the depository: Guangzhou, Guangdong Province. The 16S rDNA sequence of the strain is shown in SEQ ID NO. 1.

[0006] Furthermore, the strain is used to degrade nitrate nitrogen, nitrite nitrogen, and COD in wastewater.

[0007] Furthermore, the wastewater has a salinity ≤40g / L, a C / N ratio of 2~12, and a pH range of 7.0~10.0.

[0008] Furthermore, the temperature range for wastewater treatment by the strain is 30℃~40℃, and the shaking speed is 160rpm~280rpm.

[0009] Furthermore, the strain exhibits a maximum nitrate nitrogen degradation rate of 140.95 mg / (L·h) and a maximum nitrite nitrogen degradation rate of 126.88 mg / (L·h).

[0010] The above-mentioned aerobic denitrifying bacteria are used in wastewater treatment.

[0011] Furthermore, the aerobic denitrifying bacteria of the present invention are applied to the treatment of wastewater from stainless steel plants.

[0012] A method for treating nitrogen-containing wastewater includes the following steps: (1) The above-mentioned aerobic denitrifying bacteria were inoculated into the enrichment medium and cultured, and the pH of the enrichment medium was adjusted to 7.5; (2) Adjust the pH value of nitrogen-containing wastewater, remove heavy metals and / or fluoride ions from the wastewater, filter the precipitate, and obtain pretreated wastewater; (3) Add the aerobic denitrifying bacteria enriched in step (1) to the pretreated wastewater for aeration.

[0013] The technical solution provided by this invention may include the following beneficial effects: The aerobic denitrifying bacteria of this invention belong to *Schizophyllum commune* C3 and can carry out denitrification reactions in an aerobic environment, avoiding the fluctuations in denitrification efficiency caused by difficulties in creating an anaerobic environment (such as improper aeration control, sludge stratification, etc.). This strain can directly perform denitrification in aerobic environments such as aeration tanks and eutrophic water bodies in wastewater treatment plants, without the need to create additional anaerobic zones. It is especially suitable for treating wastewater with large load fluctuations and unstable dissolved oxygen (such as domestic sewage and industrial wastewater).

[0014] The aerobic denitrifying bacteria of this invention can efficiently remove inorganic nitrogen such as nitrite and nitrate from water bodies under high concentration inorganic nitrogen conditions (750 mg / L). It can rapidly remove nitrate nitrogen from nitrogen-containing wastewater with a C / N ratio of 4 to 12, without nitrite accumulation. It can also grow at salinity up to 40 g / L and rapidly reduce nitrate nitrogen. In particular, when the salinity is ≤20 g / L, the removal rate of nitrate nitrogen reaches 100% within 24 hours, without nitrite accumulation. It has broad environmental adaptability and great application potential. Attached Figure Description

[0015] Figure 1The graph shows the effect of the aerobic denitrifying bacteria of this invention on the removal of nitrate and nitrite nitrogen under different carbon-to-nitrogen ratios. Figure 2 These are graphs showing the removal effects of the aerobic denitrifying bacteria of this invention on nitrate and nitrite nitrogen at different temperatures. Figure 3 The graph shows the effect of the aerobic denitrifying bacteria of this invention on the removal of nitrate and nitrite nitrogen under different dissolved oxygen concentrations. Figure 4 The graph shows the removal effect of the aerobic denitrifying bacteria of this invention on nitrate and nitrite nitrogen at different pH values. Figure 5 The graph shows the effect of the aerobic denitrifying bacteria of this invention on the removal of nitrate and nitrite nitrogen at different salinities. Figure 6 This is a graph showing the removal rates of nitrate and nitrite nitrogen by the aerobic denitrifying bacteria of this invention.

[0016] Figure 7 This is a diagram illustrating the effect of the aerobic denitrifying bacteria of this invention on wastewater treatment in a stainless steel plant. Figure 8 This is a schematic diagram of the small-scale biochemical system of the present invention. Detailed Implementation

[0017] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the present invention.

[0018] An aerobic denitrifying bacterium, strain C3 of *Schönleinii*, is deposited at the Guangdong Provincial Center for Microbial Culture Collection (GDMCC) under accession number GDMCC No. 66733. The 16S rDNA sequence of this strain is shown in SEQ ID NO. 1.

[0019] The aerobic denitrifying bacteria of this invention are used to degrade nitrate nitrogen, nitrite nitrogen, and COD in wastewater. Under the following conditions: wastewater salinity ≤40 g / L, C / N ratio 2–12, pH range 7.0–10.0, wastewater temperature range 30°C–40°C, and shaking speed 160 rpm–280 rpm, this strain can efficiently degrade inorganic nitrogen in wastewater, exhibits a wide environmental adaptability range, and demonstrates a high nitrate nitrogen removal rate. The strain of this invention achieves a maximum nitrate nitrogen degradation rate of 140.95 mg / (L·h) and a maximum nitrite nitrogen degradation rate of 126.88 mg / (L·h), significantly improving the speed of wastewater denitrification treatment.

[0020] The aerobic denitrifying bacteria of this invention are applied to wastewater treatment, especially to the treatment of wastewater from stainless steel plants.

[0021] Accordingly, the present invention provides a method for treating nitrogen-containing wastewater, comprising the following steps: (1) The above-mentioned aerobic denitrifying bacteria were inoculated into the enrichment medium and cultured, and the pH of the enrichment medium was adjusted to 7.5; (2) Adjust the pH value of nitrogen-containing wastewater, remove heavy metals and / or fluoride ions from the wastewater, filter the precipitate, and obtain pretreated wastewater; (3) Add the aerobic denitrifying bacteria enriched in step (1) to the pretreated wastewater for aeration.

[0022] The above method involves pretreatment of nitrogen-containing wastewater to prevent heavy metals in the wastewater from affecting the activity of aerobic denitrifying bacteria. The aeration stage is used to increase the oxygen content in the water, providing oxygen for the aerobic denitrifying bacteria and ensuring the denitrification effect.

[0023] The invention is further illustrated below with specific experiments. It should be understood that these experiments are for illustrative purposes only and not for limiting the scope of the invention. Experimental methods in the following examples, unless otherwise specified, are generally performed according to conventional methods and conditions or as per the product instructions. The reagents mentioned are commercially available unless otherwise specified; and the performance of products from different sources does not have a significant impact.

[0024] Experiment 1: Screening of the aerobic denitrifying bacteria of the present invention 1.1. Enrichment: Activated sludge from the stainless steel plant's wastewater treatment station was inoculated into a 250 mL Erlenmeyer flask containing 100 mL of enrichment medium at a volume ratio of 0.05:1. The flask was incubated at 30℃ and 200 rpm for 24 h with shaking. The enrichment medium consisted of: 5 g KNO3, 1.5 g KH2PO4, 10.553 g Na2HPO4·12H2O, 0.1 g MgSO4, 15.587 g sodium succinate hexahydrate, and 2 mL of trace element solution. The pH of the enrichment medium was adjusted to 7.0.

[0025] 1.2. Filtering 1.2.1 Initial screening: Take 0.1 mL of the enriched solution obtained in step 1 and perform a series of serial dilutions with sterile water (10⁻⁶). 0 10 -1 10 -2 10 -3 10 -4 10 -5 10 -6 The cultures were then spread onto solid BTB medium and incubated at 28°C for 48 hours. Colonies that turned blue were then picked and inoculated onto solid BTB medium using the streak method, incubated at 28°C for 48 hours, and then isolated and purified to obtain the bacterial strain. The formula for solid BTB medium was: KNO3 5g, KH2PO4 1.5g, Na2HPO4·12H2O 10.553g, MgSO4 0.1g, sodium succinate hexahydrate 15.587g, trace element solution 2mL, agar 15g, and 1mL of 1% bromothymol blue solution; the pH of the solid BTB medium was adjusted to 7.3.

[0026] 1.2.2 Secondary Screening: The bacterial strains obtained in step 2.1 were inoculated into 18×180mm test tubes containing 5mL of aerobic denitrification medium. After incubation at 30℃ and 200rpm for 24h, samples were taken and filtered through a 0.22μm filter. The concentrations of nitrate nitrogen and nitrite nitrogen before and after incubation were measured to obtain the strain with the best denitrification capacity, i.e., the aerobic denitrifying bacteria. The formulation of the aerobic denitrification medium was as follows: 5g KNO3, 1.5g KH2PO4, 10.553g Na2HPO4·12H2O, 0.1g MgSO4, 15.587g sodium succinate hexahydrate, and 2mL trace element solution. The pH of the medium was adjusted to 7.5. The formula for the trace element solution is: MnCl2·4H2O 5.06g, FeSO4·7H2O 5.0g, ZnSO4 2.2g, EDTA 50.0g, CaCl2 5.5g, CuSO4·5H2O 1.57g, (NH4)6Mo7O 24Add 1.1g of 4H2O and 1.61g of CoCl2·6H2O, and bring the volume to 1000mL with H2O; adjust the pH of the trace element solution to 7.0–7.5.

[0027] Experiment 2: The denitrification effect of the aerobic denitrifying bacteria of this invention on nitrogen-containing wastewater with different carbon-to-nitrogen ratios. 2.1. Preparation of bacterial suspension: Aerobic denitrifying bacteria were inoculated into a 250 mL Erlenmeyer flask containing 100 mL of enrichment medium and cultured at 30 °C and 200 rpm for 48 h to obtain bacterial suspension. The OD600 of the bacterial suspension was adjusted to 2.0 with sterile water.

[0028] 2.2. Take 2 mL of the bacterial culture obtained in step 1 from 6 groups and inoculate them into 250 mL Erlenmeyer flasks containing 150 mL of denitrification medium with different carbon-to-nitrogen ratios, respectively, to simulate nitrogen-containing wastewater. Incubate at 30℃ and 200 rpm on a shaker. Measure OD600 and NO2 at 10 h, 13 h, 16 h, 19 h, and 24 h, respectively. - -N, NO3 - -N, each experiment is repeated 3 times.

[0029] The formulation of a denitrification medium with a C / N ratio of 4 is as follows: 5g KNO3, 1.5g KH2PO4, 10.553g Na2HPO4·12H2O, 0.1g MgSO4, 15.587g sodium succinate hexahydrate, and 2mL trace element solution; the pH of the medium is adjusted to 7.5. Denitrification media with different C / N ratios are obtained by adjusting the concentration of sodium succinate hexahydrate, resulting in C / N ratios of 2, 4, 6, 8, 10, and 12.

[0030] Culture results as follows Figure 1 As shown, when the C / N ratio increases from 2 to 4, after 24 hours of cultivation, NO3... - The removal rate of -N is accelerated, and there is no accumulation of nitrite; then, further increasing the carbon source concentration further reduces its effect on NO3-. - The removal rate of -N actually decreases. Therefore, the optimal C / N ratio for the aerobic denitrifying bacteria of this invention is 4, and they exhibit a higher degradation rate when the C / N ratio of nitrogen-containing wastewater is 2-12.

[0031] Experiment 3: Nitrogen removal effect of the aerobic denitrifying bacteria of the present invention at different temperatures 3.1. Preparation of bacterial suspension: Aerobic denitrifying bacteria were inoculated into a 250 mL Erlenmeyer flask containing 100 mL of enrichment medium and cultured at 30 °C and 200 rpm for 48 h to obtain bacterial suspension. The OD600 of the bacterial suspension was adjusted to 2.0 with sterile water.

[0032] 3.2. Take 2 mL of the bacterial solution obtained in step (1) from 5 groups and inoculate them into 250 mL Erlenmeyer flasks containing 150 mL of denitrification medium, i.e., simulate nitrogen-containing wastewater. Incubate on a shaker at 20℃, 25℃, 30℃, 35℃, and 40℃, with a shaker speed of 200 rpm. Measure OD600 and NO2 at 10h, 13h, 16h, 19h, and 24h, respectively. - -N, NO3 - -N, each experiment was repeated 3 times. The denitrification medium was the same as in Experiment 2, with a C / N ratio of 4.

[0033] Culture results as follows Figure 2 As shown, after culturing for 24 hours at temperatures ranging from 20℃ to 40℃, aerobic denitrifying bacteria showed resistance to NO3-. - The removal rate of -N reaches 100%, but the intermediate product of the degradation reaction, nitrite nitrogen, accumulates at 20℃ and 25℃, reaching 382.39 mg / L and 32.32 mg / L, respectively. Therefore, the aerobic denitrifying bacteria of the present invention can carry out aerobic denitrification at 20℃ to 40℃, with the most suitable temperature range being 30℃ to 40℃.

[0034] Experiment 4: Nitrogen removal effect of the aerobic denitrifying bacteria of the present invention under different dissolved oxygen concentrations 4.1. Preparation of bacterial suspension: Aerobic denitrifying bacteria were inoculated into a 250 mL Erlenmeyer flask containing 100 mL of enrichment medium and cultured at 30 °C and 200 rpm for 48 h to obtain bacterial suspension. The OD600 of the bacterial suspension was adjusted to 2.0 with sterile water.

[0035] 4.2. Take 2 mL of the bacterial culture obtained in step 1 from 6 groups and inoculate them into 250 mL Erlenmeyer flasks containing 150 mL of denitrification medium, i.e., simulating nitrogen-containing wastewater. Incubate at 30 °C on a shaker with shaking speeds of 80 rpm, 120 rpm, 160 rpm, 200 rpm, 240 rpm, and 280 rpm to control dissolved oxygen concentration. Measure OD600 and NO2 at 10 h, 13 h, 16 h, 19 h, and 24 h, respectively. - -N, NO3 - -N, each experiment was repeated 3 times. The denitrification medium was the same as in Experiment 2, with a C / N ratio of 4.

[0036] Culture results as follows Figure 3 As shown, the degradation rate of nitrate nitrogen significantly increased from 80 rpm to 160 rpm, while the degradation rate decreased with further increases in dissolved oxygen concentration. The degradation rate of nitrite nitrogen significantly increased from 80 rpm to 280 rpm. No nitrate nitrogen or nitrite nitrogen accumulated after 24 hours of cultivation when the shaking speed was between 160 rpm and 280 rpm; therefore, the optimal shaking speed was between 160 rpm and 280 rpm.

[0037] Experiment 5: Denitrification effect of the aerobic denitrifying bacteria of the present invention at different pH values 5.1. Preparation of bacterial suspension: Aerobic denitrifying bacteria were inoculated into a 250 mL Erlenmeyer flask containing 100 mL of enrichment medium and cultured at 30 °C and 200 rpm for 48 h to obtain bacterial suspension. The OD600 of the bacterial suspension was adjusted to 2.0 with sterile water.

[0038] 5.2. Take 2 mL of the bacterial culture obtained in step 1 from 6 groups and inoculate them into 250 mL Erlenmeyer flasks containing 150 mL of denitrification medium with different pH values, i.e., simulated nitrogen-containing wastewater. The initial pH values ​​of the denitrification medium are 6.0, 7.0, 8.0, 9.0, 10.0, and 11.0, respectively. Incubate at 30℃ and 200 rpm on a shaker. Measure OD600 and NO2 at 10h, 13h, 16h, 19h, and 24h, respectively. - -N, NO3 - -N, each experiment was repeated 3 times. The denitrification medium was the same as in Experiment 2, with a C / N ratio of 4. The initial pH of the denitrification medium was adjusted using 1 mol / L HCl and 1 mol / L NaOH solutions.

[0039] Culture results as follows Figure 4 As shown, when the pH value is 7.0–10.0, after 24 hours of cultivation, aerobic denitrifying bacteria showed resistance to NO2. - -N, NO3 - The removal rate of -N reached 100%. When the pH value is 6.0 and 11.0, the denitrification process is delayed. Therefore, the most suitable pH range for the aerobic denitrifying bacteria of this invention is 7.0-10.0.

[0040] Experiment 6: Nitrogen removal effect of the aerobic denitrifying bacteria of the present invention under different salinities 6.1. Preparation of bacterial suspension: Aerobic denitrifying bacteria were inoculated into a 250 mL Erlenmeyer flask containing 100 mL of enrichment medium and cultured at 30 °C and 200 rpm for 48 h to obtain bacterial suspension. The OD600 of the bacterial suspension was adjusted to 2.0 with sterile water.

[0041] 6.2. Take 2 mL of the bacterial culture obtained in step 1 from 5 groups and inoculate them into 250 mL Erlenmeyer flasks containing 150 mL of denitrification medium with different salinities, respectively, to simulate nitrogen-containing wastewater. Incubate at 35℃ and 240 rpm for 48 h. Measure OD600 and NO2 at 7 h, 17 h, 24 h, 31 h, 41 h, and 48 h, respectively. - -N, NO3 --N, each experiment was repeated 3 times. The denitrification medium was the same as in Experiment 2, with a C / N ratio of 4 and a pH of 8. The concentration of NaCl in the denitrification medium was controlled to be 0, 10 g / L, 20 g / L, 30 g / L, and 40 g / L to simulate saline wastewater.

[0042] Culture results as follows Figure 5 As shown, nitrate removal exhibits varying degrees of lag with increasing salinity, but all reach 100% removal rate within 24 hours. When salinity ≥30 g / L, nitrite still accumulates after 48 hours. Therefore, the aerobic denitrifying bacteria in this experiment are best suited for treating wastewater with salinity ≤20 g / L, demonstrating excellent denitrification capabilities in both freshwater and higher salinity conditions.

[0043] Experiment 7: Nitrogen removal rate of the aerobic denitrifying bacteria of this invention 7.1. Preparation of bacterial suspension: Aerobic denitrifying bacteria were inoculated into a 250 mL Erlenmeyer flask containing 100 mL of enrichment medium and cultured at 30 °C and 200 rpm for 48 h to obtain bacterial suspension. The OD600 of the bacterial suspension was adjusted to 2.0 with sterile water.

[0044] 7.2. Take 2 mL of the bacterial culture obtained in step (1) and inoculate it into a 250 mL Erlenmeyer flask containing 150 mL of denitrification medium, i.e., simulate nitrogen-containing wastewater. Incubate at 35℃ and 240 rpm for 24 h, and measure NO2 every 3 h. - -N, NO3 - -N, the experiment was repeated 3 times. The denitrification medium was the same as in Experiment 2, with a C / N ratio of 4 and a pH adjusted to 8.

[0045] Culture results as follows Figure 6 As shown, the maximum degradation rate of nitrate nitrogen was 140.95 mg / (L·h), and the maximum degradation rate of nitrite nitrogen was 126.88 mg / (L·h).

[0046] Experiment 8: Treatment of Stainless Steel Plant Wastewater with Aerobic Denitrifying Bacteria of the Invention In the pickling process of stainless steel production, nitric acid is often used as the main agent, resulting in wastewater containing a large amount of nitrate ions. After pickling, a large amount of acid residue remains on the steel surface, requiring multiple rinsings. While the nitrate concentration in the rinsing wastewater is lower than that in the pickling wastewater, the large volume of rinsing water (usually several to more than ten times the volume of the pickling wastewater) leads to a higher total nitrogen discharge, making it a major source of nitrogenous wastewater from stainless steel plants. The aerobic denitrifying bacteria of this invention can rapidly denitrify nitrogenous wastewater from stainless steel plants. Specific experimental steps are as follows.

[0047] 8.1. Preparation of bacterial culture: Aerobic denitrifying bacteria preserved on slant agar in a refrigerator were inoculated into enrichment medium and cultured at 35℃ and 240 rpm for 24 h, with a total enrichment of 3 L. The formula of each liter of enrichment medium was: KNO3 5 g, KH2PO4 1.5 g, Na2HPO4·12H2O 10.553 g, MgSO4 0.1 g, sodium succinate hexahydrate 15.587 g, and trace element solution 2 mL. The pH of the medium was adjusted to 7.5.

[0048] 8.2. Pretreatment of industrial wastewater from stainless steel industry: Sodium hydroxide and calcium fluoride were added to the wastewater to adjust the pH, remove heavy metals and fluoride ions, filter the precipitate, and obtain the pretreated wastewater. The water quality is shown in Table 1.

[0049] Table 1 8.3. Place the enriched 3L culture medium into a small biochemical system ( Figure 8 In this process, the influent is pretreated stainless steel wastewater (diluted to a nitrate concentration of 1-2 g / L, with methanol added as the carbon source), with an influent flow rate of 1 ml / min and intermittent aeration for 2 hours over 24 hours. The quantitatively pretreated stainless steel wastewater is circulated in a small-scale biological system.

[0050] 8.4. Samples are taken every 24 hours, centrifuged, filtered through a 0.22 μm filter, and NO3 is measured. - -N, NO2 - -N, COD, results are as follows Figure 7 As shown: After the system stabilized, the influent nitrate nitrogen was 439 mg / L. With the addition of methanol to reduce the COD to 2264 mg / L, the COD and nitrate nitrogen removal rates on the 11th day of the experiment were 97.14% and 100%, respectively. There was no accumulation of nitrite nitrogen during the process, and the final pH value was 8.42, which was higher than the initial pH = 7.5. This shows that the aerobic denitrifying bacteria of the present invention can adapt to stainless steel industrial wastewater with high nitrate nitrogen concentration and effectively remove nitrogen and organic matter.

[0051] Other components and operations of the aerobic denitrifying bacteria according to the present invention and their applications are known to those skilled in the art and will not be described in detail here. When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. The described performance can be achieved within the proportions ranged in the present invention. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by those skilled in the art to which this invention pertains.

[0052] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An aerobic denitrifying bacterium, characterized by, The strain is Sphingomonas sp. C3, which is preserved in Guangdong Microbial Culture Collection Center with the preservation number of GDMCC No. 66733, and the 16S rDNA sequence of the strain is shown as SEQ ID NO.

1.

2. The facultative anaerobic denitrifier according to claim 1, characterized in that, The strain is used for degrading nitrate nitrogen, nitrite nitrogen and COD in sewage.

3. The facultative anaerobic denitrifier according to claim 2, characterized in that, The salinity of the sewage is ≤40 g / L, the C / N value is 2-12, and the pH value ranges from 7.0 to 10.

0.

4. The facultative anaerobic denitrifier according to claim 3, characterized in that, The temperature range for treating sewage by the strain is 30-40℃, and the rotation speed of the shaking table is 160-280 rpm.

5. The facultative anaerobic denitrifier according to claim 4, characterized in that, The maximum degradation rate of nitrate nitrogen is 140.95 mg / (L·h), and the maximum degradation rate of nitrite nitrogen is 126.88 mg / (L·h).

6. The application of the aerobic denitrifying bacteria in claims 1-5 in treating sewage.

7. Use according to claim 6, characterized in that, The application in treating sewage of a stainless steel factory.

8. A method for treating nitrogen-containing wastewater, characterized by, The method comprises the following steps: (1) inoculating the aerobic denitrifying bacteria in claims 1-5 into an enrichment medium for culture, and adjusting the pH value of the enrichment medium to 7.5; (2) adjusting the pH value of the nitrogen-containing sewage, removing heavy metals and / or fluoride ions in the sewage, filtering the precipitate, and obtaining pretreated sewage; (3) adding the enriched aerobic denitrifying bacteria in step (1) into the pretreated sewage for aeration treatment.

Images