Method for optimizing microbial ecological niche and enhancing nitrogen-containing wastewater cooperative treatment by denitrifying bacteria

Abstract

The invention relates to the technical field of sewage treatment, and provides a method for optimizing microbial ecological niche to enhance nitrogen-containing wastewater cooperative treatment by denitrifying bacteria, which comprises the following steps: S1, pretreating wastewater, S2, constructing an autotrophic nitrogen removal reactor, and S3, pumping the nitrogen-containing wastewater into the reactor for treatment. Sulfides in the wastewater enable anaerobic ammonia oxidation functional bacteria to occupy a dominant ecological niche in particles and enable sulfur autotrophic denitrification functional bacteria to occupy a dominant ecological niche in flocs; effective cooperation of anaerobic ammonia oxygen bacteria particles and sulfur autotrophic denitrifying bacteria floc ensures efficient operation of an autotrophic nitrogen removal process, and the total nitrogen removal efficiency and environmental tolerance of an autotrophic nitrogen removal system are greatly improved. Compared with the prior art, the method has the advantages that sludge granulation is promoted, meanwhile, the good coupling effect of multiple denitrifying functional bacteria is achieved, the autotrophic nitrogen removal process is helped to resist environmental impact, and application of the autotrophic nitrogen removal process in complex wastewater treatment is further promoted.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and in particular to a method for optimizing microbial niches and strengthening denitrification bacteria to collaboratively treat nitrogen-containing wastewater. Background Art

[0002] The autotrophic denitrification process does not rely on organic matter and has the advantages of low energy consumption, low sludge production and low greenhouse gas production, providing a new way for low-carbon denitrification and energy saving and consumption reduction in sewage treatment plants. However, the doubling time of autotrophic denitrification functional bacteria is long (for example, the doubling time of anaerobic ammonia-oxidizing bacteria is about 2 to 12 days). Effective retention of autotrophic denitrification functional bacteria is the key to maintaining stable operation of the reactor, and the formation of autotrophic denitrification functional bacteria granules is one of the effective ways to overcome this problem. Autotrophic denitrification functional bacteria granules have outstanding advantages such as high biological density, high total nitrogen removal load and strong resistance to complex environments. They have become the most promising sludge form for autotrophic denitrification technology. At present, the main strategies to promote microbial granulation include increasing the amount of inorganic salt ions (such as Ca 2+ Mg 2+ The patent CN114920355B discloses a method for adjusting the sedimentation performance of aerobic granular microbial aggregates, but the disadvantage of the invention is that the preparation of mixed powder is relatively complicated. The patent CN117486369A discloses a device and method for rapid cultivation of granular sludge in a continuous flow anaerobic ammonia oxidation denitrification process, but the disadvantage of the invention is that the device process is relatively long.

[0003] In summary, although these methods are effective, they are accompanied by the challenge of high costs, which limits their popularization in large-scale applications. Therefore, it is urgent to find an economical and sustainable method to accelerate the granulation of autotrophic denitrification sludge. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of existing autotrophic denitrification sludge granulation, such as high cost, slow process and difficulty in popularization, and to provide a method for optimizing the microbial niche to strengthen the denitrification bacteria to synergistically treat nitrogen-containing wastewater.

[0005] The present invention utilizes the addition of sulfide to promote the secretion of extracellular polymers (EPS) by autotrophic denitrification sludge. On the one hand, EPS usually plays an important role in the floc granulation process, and high EPS secretion is conducive to particle formation and particle size increase. On the other hand, sulfide will first be converted into biosulfur as an intermediate (S 2- →S 0), which can alleviate the toxic effects of sulfide to a certain extent. At the same time, the particle size of biological sulfur is usually <1μm and has strong adsorption properties, which can act as a micronucleus to accelerate sludge granulation. In view of this, sulfide may be a potential biocompatible agent that helps the granulation of autotrophic denitrification sludge. Sulfide can induce the proliferation of sulfur autotrophic denitrification functional bacteria (such as Thiobacillus), but the ecological niche and interaction of functional bacteria in autotrophic denitrification sludge aggregates (granules-flocs) are still unclear. Clarifying these issues will greatly promote the application of autotrophic denitrification granular processes.

[0006] The present invention clarifies the ecological niche and interaction mechanism of functional bacteria in autotrophic denitrification sludge, and based on this, accelerates the granulation of anaerobic ammonia oxidation sludge in the reactor by adding sulfide, and simultaneously induces the proliferation of sulfur autotrophic denitrifying bacteria in flocs, so that the denitrification functional bacteria undergo niche differentiation, provides respective advantageous ecological niches for various denitrification functional bacteria in the autotrophic denitrification system, strengthens the coupling effect of anaerobic ammonia oxidation bacteria in the particles and sulfur autotrophic denitrifying bacteria in the flocs, improves the nitrogen removal efficiency of the autotrophic denitrification system, and thus promotes the application of the autotrophic denitrification system in complex wastewater.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] The technical solution of the present invention provides a method for optimizing the microbial niche to strengthen the denitrification bacteria to collaboratively treat nitrogen-containing wastewater, the method comprising the following steps:

[0009] S1 detection of S in wastewater 2- -S, NH4 + -N, NO2 - -N、NO3 - -N concentration, and control S 2- -S concentration is 10~50mg / L, NH4 + -N concentration is 100~250mg N / L, NO2 - -N concentration is 100~300mg N / L, NO3 - -N concentration is 0 to 20 mg N / L;

[0010] S2 places the autotrophic denitrification sludge in a reactor, wherein the autotrophic denitrification sludge contains anaerobic ammonia oxidation functional bacteria and sulfur autotrophic denitrification functional bacteria;

[0011] S3 passes wastewater into the reactor, and the sulfide in the wastewater enables the anaerobic ammonium oxidation functional bacteria to occupy a dominant ecological niche in the particles, and at the same time enables the sulfur autotrophic denitrification functional bacteria to occupy a dominant ecological niche in the flocs; the anaerobic ammonium oxidation functional bacteria and the sulfur autotrophic denitrification functional bacteria have a synergistic effect, and the anaerobic ammonium oxidation functional bacteria convert ammonia nitrogen and nitrite nitrogen in the wastewater into nitrogen gas and nitrate nitrogen; the sulfur autotrophic denitrification functional bacteria convert nitrate nitrogen in the wastewater and nitrate nitrogen generated by anaerobic ammonium oxidation into nitrogen gas, and the nitrogen gas is directly discharged from the reactor, and the treated wastewater flows out of the reactor.

[0012] Furthermore, the wastewater is the effluent from the leachate of an actual landfill after denitrification and short-range nitrification treatment.

[0013] Furthermore, in some specific embodiments, a synergistic denitrification system is constructed by simulating wastewater with a nutrient solution; the nutrient solution, the solute includes ammonium salts, nitrites, sulfides and compounds of other elements, and the solvent is deionized water; the ammonium salt is selected from any one or a combination of two or more of NH4Cl, (NH4)2SO4, (NH4)2CO3, and the influent NH4 is adjusted. + -N concentration is 100mg N / L; the nitrite is selected from any one of NaNO2, KNO2 or a combination of two or more, to adjust the influent NO2 - -N concentration is 132mg N / L; the sulfide is selected from Na2S·9H2O, and the influent S 2- -S concentration is 10mg S / L; the compounds of other elements include components with the following concentrations: KHCO3 1g / L, KH2PO4 0.025g / L, CaCl2 0.3g / L, MgCl2 0.3g / L, FeSO4·7H2O 0.015g / L, Na2EDTA0.02g / L, and 0.5mL / L of trace element concentrate; the trace element concentrate includes components with the following concentrations: 0.035g / L H3BO3, 0.625g / L CuSO4·5H2O, 0.525g / L CoCl2, 1.075g / L ZnSO4·7H2O, 0.475g / L NiCl2·6H2O, 2.475g / L MnCl2·4H2O and 0.55g / L NaMoO4·2H2O.

[0014] Furthermore, in S1, when S in the wastewater 2- -When the S concentration is lower than 10 mg / L, sulfide is added to make its concentration 10-50 mg / L; the sulfide is preferably Na2S·9H2O; when the S 2- -S concentration is higher than 50 mg / L, and is diluted to a concentration of 10 to 50 mg / L.

[0015] Furthermore, the autotrophic denitrification sludge in S2, i.e., anaerobic ammonia oxidation sludge, is first washed more than three times with 0.1 mM PBS buffer at pH 7.4-7.6 when used.

[0016] Furthermore, the anaerobic ammonium oxidation functional bacteria in S2 are Anammox bacteria, including Candidatus Brocadia; the sulfur autotrophic denitrification functional bacteria are SADN bacteria, including Thiobacillus.

[0017] Furthermore, the particle size of the anaerobic ammonium oxidizing functional bacteria particles in S2 is >0.2 mm, and the particle size of the sulfur autotrophic denitrifying bacteria flocs is <0.2 mm.

[0018] Furthermore, in S2, the volatile suspended solids concentration in the autotrophic denitrification sludge in the reactor is controlled to be 3000-4000 mg VSS / L, adjusted using PBS buffer; the dissolved oxygen content of the wastewater in the reactor is <0.005 mg / L; the temperature is 31-33°C; and the pH value ranges from 7.4 to 7.6.

[0019] Furthermore, the sulfide contained in the wastewater in S3 is converted into sulfur element as granular micronuclei, while promoting the proliferation of sulfur autotrophic denitrifying functional bacteria.

[0020] Furthermore, in S3, the water inlet and outlet were controlled by a pump, the water exchange ratio was 0.5, the hydraulic retention time in the autotrophic denitrification reactor was 16 h, and three cycles were run every day. In each cycle, water was introduced for 5 min, stirred for 400 min, allowed to settle for 60 min, drained for 10 min, and idle for 5 min.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) The present invention utilizes sulfide addition to promote the secretion of extracellular polymers of anaerobic ammonium oxidation sludge, accumulate an appropriate amount of biosulfur as granulation micronuclei, and promote the proliferation of filamentous bacteria as granulation skeletons. These multiple effects accelerate the granulation of anaerobic ammonium oxidation sludge; at the same time, sulfide addition induces the proliferation of sulfur autotrophic denitrification functional bacteria in flocs. Finally, the ecological niche of denitrification functional bacteria is differentiated, and they occupy the optimal ecological niche in particles and flocs respectively.

[0023] (2) The denitrification functional bacteria of the present invention occupy a dominant ecological niche. The anaerobic ammonia oxidation sludge particles convert ammonia nitrogen and nitrite nitrogen in the influent into nitrogen gas and nitrate nitrogen. The nitrate nitrogen is then reduced to nitrogen gas by the sulfur autotrophic denitrifying bacteria in the flocs, which is conducive to the efficient and close cooperation of the denitrification functional bacteria and realizes long-term stable and efficient denitrification of the autotrophic denitrification system.

[0024] (3) The efficient cooperation between the denitrification functional bacteria of the present invention helps the autotrophic denitrification granular system to cope with environmental shocks and has significant advantages in treating complex wastewater.

[0025] (4) The method of the present invention has the advantage of sustainability, and sodium sulfide can be derived from industrial wastewater, which has the advantage of economic sustainability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The test results of the sludge body of the autotrophic denitrification reactor provided in Example 1, Example 2, Example 3 and the comparative example of the present invention;

[0027] Figure 2 The particle size distribution results of the autotrophic denitrification functional bacteria provided in Example 1 and Example 2 of the present invention;

[0028] Figure 3 The activity results of the autotrophic denitrification functional bacteria in particles and flocs provided in Examples 1 and 2 of the present invention;

[0029] Figure 4 The relative abundance results of the autotrophic denitrification functional bacteria in particles and flocs provided in Examples 1 and 2 of the present invention;

[0030] Figure 5 The relative abundance results of the main nitrogen transformation pathways in the particles and flocs of the autotrophic denitrification reactor provided in Examples 1 and 2 of the present invention;

[0031] Figure 6 A schematic diagram of synergistic denitrification by enhancing autotrophic denitrification functional bacteria based on niche differentiation in the autotrophic denitrification reactor provided in an embodiment of the present invention; the numbers in the figure indicate: 1. water inlet tank; 2. peristaltic pump; 3. autotrophic denitrification reactor; 4. autotrophic denitrification granular sludge. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with specific embodiments. It should be noted that the following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several variations and improvements can also be made, which all belong to the protection scope of the present invention.

[0033] In the following examples and comparative examples, unless otherwise specified, raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0034] Example 1

[0035] This embodiment provides a method for optimizing the microbial niche to strengthen the synergistic denitrification of denitrifying bacteria, and constructs a highly efficient synergistic denitrification system of autotrophic denitrifying functional bacteria by simulating nitrogen-containing wastewater with a nutrient solution artificially prepared in the laboratory, including the following steps:

[0036] (1) Pretreatment of autotrophic denitrification sludge: The seed sludge required in Example 1 was taken from the anaerobic ammonium oxidation sludge (i.e., autotrophic denitrification sludge) in the laboratory that maintained good nitrogen removal performance for a long time (5 years), and the total nitrogen removal efficiency was maintained at 89%; the activated sludge was washed 3 times with a 0.1mM pH=7.5 phosphate buffer solution (PBS), and placed in a sequencing batch reactor with an effective volume of 1.2L (the sequencing batch reactor helps to strengthen the in-situ granulation of autotrophic denitrification functional bacteria) to construct an autotrophic denitrification sludge reactor. The volatile suspended solids concentration (i.e., anaerobic ammonium oxidation sludge concentration, MLVSS) of the anaerobic ammonium oxidation sludge was measured, adjusted to 3000-3245mg / L using PBS, and nitrogen was aerated for 30min to keep the reactor in anoxic state (i.e., dissolved oxygen <0.005mg / L).

[0037] (2) Preparation of influent nutrient solution (simulated wastewater): In the simulated wastewater, NH4Cl was used to adjust the NH4 + -N concentration is 100 mg N / L, and NaNO2 is used to adjust NO2 - -N concentration was 132 mg N / L, and Na2S was used to adjust S 2- -S concentration is 10mg S / L; other elements (g / L) include: KHCO3 1; KH2PO4, 0.025; CaCl2, 0.3; MgSO4·7H2O, 0.3; FeSO4·7H2O, 0.015; Na2EDTA, 0.02 and trace element concentrate 0.5mL / L. Among them, the trace element concentrate (g / L) includes: H3BO3, 0.035; CuSO4·5H2O, 0.625; CoCl2, 0.525; ZnSO4·7H2O, 1.075; NiCl2·6H2O, 0.475; MnCl2·4H2O, 2.475; NaMoO4·2H2O, 0.55.

[0038] (3) Operation of the autotrophic denitrification reactor: water is intermittently fed and discharged through a peristaltic pump, the water exchange ratio is set to 0.5, and the hydraulic retention time is 16 h. The temperature of the reactor working area is controlled at around 32 °C, and the dissolved oxygen is <0.005 mg / L. The reactor runs 3 cycles a day (i.e. 1 cycle is 8 h), each cycle includes 5 min of water intake, 400 min of stirring, 60 min of static sedimentation, 10 min of drainage, and 5 min of idleness. Water is fed in every day in the form of artificial water distribution.

[0039] Every three days, water samples were taken with syringes to determine the concentrations of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen to calculate the total nitrogen removal efficiency (TNRE) and total nitrogen removal rate (TNRR). The results are shown in Table 1. The test method for ammonia nitrogen concentration is Nessler's reagent colorimetry; the test method for nitrite nitrogen concentration is N-(1-naphthyl)-ethylenediamine dihydrochloride spectrophotometry; the test method for nitrate nitrogen concentration is ultraviolet spectrophotometry; the above test methods are conventional determination methods in the art; the calculation formula for total nitrogen removal efficiency is: TNRE = (influent total nitrogen concentration - effluent total nitrogen concentration) / influent total nitrogen concentration; the calculation formula for total nitrogen removal rate is: TNRR = (influent total nitrogen concentration - effluent total nitrogen concentration) / hydraulic retention time.

[0040] During the operation of the reactor, the sludge morphology changes were observed and the sludge particle size distribution was determined (the sludge volume test results and particle size distribution were as follows: Figure 1 and Figure 2 As shown in the figure, after 60 days of operation, it was observed that red granular sludge was gradually generated in the autotrophic denitrification reactor, and the average particle size D[4.3] increased from 197μm to 325μm. The average sludge particle size D[4,3] = (f1·D1+f2·D2+f3·D3+…). Where: Di represents the average particle size of the i-th particle size interval, and fi represents the percentage content of the i-th particle size interval. Use a sieve to distinguish between particles (particle size>0.2mm) and flocs (particle size<0.2mm) (results see Figure 2 ), and the anaerobic ammonium oxidation and sulfur autotrophic denitrification activities in the particles and flocs were determined respectively (the results are shown in Figure 3 ); 16S rRNA gene sequencing was used to analyze the microbial community structure and functional composition in particles and flocs (results are shown in Figures 4-5 ). The reactor was then operated for 400 days to further verify the stability of the particle denitrification process.

[0041] Example 2

[0042] In order to further verify the universality of the method provided in Example 1, Example 2 was operated in the same manner as Example 1. The parameters and results of the measurement are shown in Tables 1 and Figures 1 to 5 The results show that the addition of sulfide helps the sludge in Example 2 to granulate and form a particle-flocculation mixed system. At the same time, the particles (particle size>0.2mm) and flocs (particle size<0.2mm) play the role of anaerobic ammonia oxidation and sulfur autotrophic denitrification, respectively, and synergistically remove nitrogen. However, it is noted that the average particle size of Example 2 is different from that of Example 1, which may be due to the random difference in the particle size of the seed sludge taken from Example 2 and Example 1.

[0043] Comparative Example

[0044] Compared with Examples 1 and 2, most of the steps are the same, except that sodium sulfide is not added in step (2).

[0045] The test results (60d) of the denitrification process performance of the reaction system of Examples 1 to 2 and Comparative Example 1 are as follows:

[0046] Changes in particle size distribution of granular sludge during the operation of the autotrophic denitrification reactor Figure 1 As shown in Table 1. Figure 2 It can be seen that the addition of sulfide (Examples 1-2) significantly increased the proportion of granular sludge (shaded part in the figure, particle size>0.2mm) in the autotrophic denitrification reactor. Compared with the control example without the addition of sulfide, the proportion of granular sludge in the autotrophic denitrification reactor of Examples 1 and 2 increased by 20% to 70%. At the same time, it can be seen from Table 1 that the average particle size D[4.3] of the sludge in Examples 1 and 2 is 325μm and 680μm, respectively, which is significantly higher than the average particle size of 217μm of the autotrophic denitrification functional bacteria in the control example without the addition of sodium sulfide, indicating that the addition of sulfide is conducive to the formation of anaerobic ammonia oxidation particles.

[0047] Figures 3 to 5 The results of niche differentiation of autotrophic denitrification functional bacteria in Examples 1 and 2 are shown. Figures 4-5 Anammox bacteria are anaerobic ammonium oxidizing bacteria; SADN bacteria are sulfur autotrophic denitrifying bacteria. Figure 3 to Figure 5 It can be seen that sulfide addition induces niche differentiation of denitrification functional bacteria in autotrophic denitrification reactors, and functional microorganisms occupy favorable niches respectively. Granular sludge (particle size> 0.2mm) in the autotrophic denitrification reactors of Example 1 and Example 2 mainly shows higher anaerobic ammonia oxidation activity, anaerobic ammonia oxidizing bacteria (Anammox bacteria, such as Candidatus Brocadia) relative abundance and anaerobic ammonia oxidation metabolic activity; flocculent sludge (particle size<0.2mm) mainly shows good sulfur autotrophic denitrification activity, and sulfur autotrophic denitrification functional bacteria (SADN bacteria, such as Thiobacillus) dominate. Anaerobic ammonia oxidizing bacteria have self-aggregation characteristics and are more likely to aggregate into particles, while sulfur autotrophic denitrifying bacteria, in view of their anoxic metabolic mechanism, are more inclined to survive in a flocculent environment containing a certain level of dissolved oxygen (compared to a strictly anaerobic environment). These results further show that sulfide addition helps to promote the synergistic denitrification of granular flocculent denitrification functional bacteria in autotrophic reactors.

[0048] Table 1 Summary of effluent nitrogen concentration and sludge particle size in Examples and Comparative Examples

[0049]

[0050] a: TNRE: total nitrogen removal efficiency; b :TNRR: Total nitrogen removal rate

[0051] Combined with the nitrogen removal efficiency of the autotrophic denitrification reactor in Table 1, it can be seen that the addition of sulfide also significantly improves the nitrogen removal efficiency of the reactor. Compared with the control example without adding sulfide, the total nitrogen concentration of the effluent of the autotrophic denitrification reactor in Example 1 and Example 2 is significantly reduced, and the nitrogen removal efficiency is improved by 7% to 10%. Figure 6 As shown in the figure, in the autotrophic denitrification reactor with sulfide addition, the anaerobic ammonia oxidation sludge particles first convert the ammonia nitrogen and nitrite nitrogen in the influent into nitrogen gas and nitrate nitrogen, and the nitrate nitrogen is then reduced to nitrogen gas by the sulfur autotrophic denitrifying bacteria in the flocs. The microorganisms in the particle flocs cooperate efficiently and closely, which improves the nitrogen removal efficiency and maintains high efficiency and stability for a long time.

[0052] Example 3

[0053] The autotrophic denitrification sludge obtained in Example 1 with optimized microbial niche and enhanced denitrification by denitrification bacteria was applied to actual wastewater treatment, and the wastewater came from actual landfill leachate. The specific operation steps are as follows:

[0054] S1 Wastewater pretreatment: Determination of NH4 in wastewater (actual landfill leachate after denitrification and short-range nitrification) + -N, NO2 - -N and S 2- -S concentration, NH4 in wastewater + -N concentration is 100~250mg N / L, NO2 - -N concentration is 100~300mg N / L, S 2- -S concentration was adjusted to 10-50 mg / L.

[0055] S2 adds the pretreated wastewater to the autotrophic denitrification reactor. During the long-term operation, a syringe is used to regularly take water samples to determine the concentrations of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen to calculate the total nitrogen removal efficiency (Total Nitrogen Removal Efficiency, TNRE) (see Table 2) and observe the sludge morphology of the reactor ( Figure 1 ).

[0056] During the long-term operation (180 days), the sludge of the autotrophic denitrification reactor maintained a granular form, and the average sludge particle size D[4.3] was 373 μm, which was consistent with the artificial simulated wastewater operation in Example 1. At the same time, the total nitrogen removal efficiency reached 89±4.3%. These results show that the addition of sulfide promotes the formation of anaerobic ammonia oxidation sludge particles, and the denitrification functional bacteria cooperate efficiently, making the autotrophic denitrification process have significant advantages in the actual complex wastewater treatment process.

[0057] Table 2 Nitrogen removal efficiency and average sludge particle size of Case 3 during long-term operation

[0058]

[0059] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for optimizing microbial niches to enhance the synergistic treatment of nitrogen-containing wastewater by denitrifying bacteria, characterized in that: The following steps are involved: S1 detects S in wastewater 2- -S, NH4 + -N, NO2 - -N、NO3 - -N concentration, and control S 2- -S concentration is 10~50mg / L, NH4 + -N concentration is 100~250mg / L, NO2 - -N concentration is 100~300mg / L, NO3 - -N concentration is 0-20 mg / L; S2 places the autotrophic denitrification sludge in a reactor, wherein the autotrophic denitrification sludge contains anaerobic ammonia oxidation functional bacteria and sulfur autotrophic denitrification functional bacteria; S3 passes wastewater into the reactor, and the sulfide in the wastewater enables the anaerobic ammonium oxidation functional bacteria to occupy a dominant ecological niche in the particles, and at the same time enables the sulfur autotrophic denitrification functional bacteria to occupy a dominant ecological niche in the flocs; the anaerobic ammonium oxidation functional bacteria and the sulfur autotrophic denitrification functional bacteria have a synergistic effect, and the anaerobic ammonium oxidation functional bacteria convert ammonia nitrogen and nitrite nitrogen in the wastewater into nitrogen gas and nitrate nitrogen; the sulfur autotrophic denitrification functional bacteria convert nitrate in the wastewater and nitrate nitrogen generated by the anaerobic ammonium oxidation reaction into nitrogen gas; the nitrogen gas is directly discharged from the reactor, and the treated wastewater flows out of the reactor.

2. The method for optimizing microbial niche and strengthening denitrification bacteria to collaboratively treat nitrogen-containing wastewater according to claim 1, characterized in that: The wastewater is the effluent from the leachate of an actual landfill after being treated with denitrification and short-range nitrification.

3. The method for optimizing microbial niche and strengthening denitrification bacteria to collaboratively treat nitrogen-containing wastewater according to claim 1, characterized in that: In S1, when S 2- -S concentration is lower than 10mg / L, by adding sulfide, its concentration is 10-50mg / L; when S in wastewater 2- -S concentration is higher than 50 mg / L, and is diluted to a concentration of 10 to 50 mg / L.

4. The method for optimizing microbial niche and strengthening denitrification bacteria to collaboratively treat nitrogen-containing wastewater according to claim 1, characterized in that: The autotrophic denitrification sludge in S2 is anaerobic ammonia oxidation sludge, which should be cleaned before use.

5. The method of optimizing microbial niche and strengthening denitrification bacteria to collaboratively treat nitrogen-containing wastewater according to claim 1, characterized in that: The particle size of the anaerobic ammonium oxidizing functional bacteria particles in S2 is >0.2 mm, and the particle size of the sulfur autotrophic denitrifying bacteria flocs is <0.2 mm.

6. The method of optimizing microbial niche and strengthening denitrification bacteria to collaboratively treat nitrogen-containing wastewater according to claim 1, characterized in that: The volatile suspended solids concentration of the autotrophic denitrification sludge in the reactor S2 was controlled to be 3000-4000 mgVSS / L and was adjusted using PBS buffer.

7. The method of optimizing microbial niche and strengthening denitrification bacteria to collaboratively treat nitrogen-containing wastewater according to claim 1, characterized in that: In S2, the dissolved oxygen content of the wastewater in the reactor is controlled to be <0.005 mg / L.

8. The method of optimizing microbial niche and strengthening denitrification bacteria to collaboratively treat nitrogen-containing wastewater according to claim 1, characterized in that: In S2, the reactor temperature is controlled at 31-33°C.

9. The method of optimizing microbial niche and strengthening denitrification bacteria to collaboratively treat nitrogen-containing wastewater according to claim 1, characterized in that: The pH value of the reactor in S2 is controlled in the range of 7.4 to 7.

6.

10. The method of optimizing microbial niche and strengthening denitrification bacteria to collaboratively treat nitrogen-containing wastewater according to claim 1, characterized in that: S3 controls the water inlet and outlet of the reactor, the water exchange ratio is 0.5, the hydraulic retention time in the autotrophic denitrification reactor is 16 hours, and 3 cycles are operated every day. Each cycle includes water inlet, stirring, static sedimentation, drainage, and idleness; the water inlet time is 5 minutes, the stirring time is 360-400 minutes, the static sedimentation time is 60-100 minutes, the drainage time is 10 minutes, and the idle time is 5 minutes.

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