Sulfur autotrophic denitrification coupled with anaerobic ammonia oxidation biofilm, construction method and application thereof

Abstract

The application provides a sulfur autotrophic denitrification coupled anaerobic ammonia oxidation biofilm, a construction method and application thereof, and comprises the following steps: inoculating mixed sludge composed of sulfur autotrophic denitrification sludge and anaerobic ammonia oxidation sludge in a reactor; wherein the MLSS of the reactor after inoculation is 1000-8000 mg / L; performing staged domestication on the mixed sludge to obtain domesticated sludge; adding carrier filler to the reactor containing the domesticated sludge, and continuously operating for more than 30 days to obtain the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation biofilm. The construction method is convenient and easy to operate, and the process flow is simple. The obtained sulfur autotrophic denitrification coupled anaerobic ammonia oxidation biofilm solves the problem that total nitrogen cannot be deeply removed in the prior art. The biofilm can be directly inoculated in an anaerobic system reactor under suitable substrate conditions, realizes stable interaction of the two denitrification processes, strengthens the total nitrogen removal performance, and has strong practical engineering application ability.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a sulfur autotrophic denitrification coupled anaerobic ammonia oxidation biofilm, its construction method, and its application. Background Technology

[0002] In wastewater denitrification, existing technologies often employ anaerobic ammonium oxidation (ANAO) to remove total nitrogen from polluted water. ANAO uses nitrite and ammonium salts as substrates, generating nitrogen gas as a byproduct under anoxic conditions with a small amount of nitrate, thus simplifying the removal of nitrogenous pollutants. Compared to traditional biological denitrification processes, ANAO offers advantages such as high efficiency and environmental friendliness, high nitrogen loading, no need for external organic carbon sources, low sludge production, and lower oxygen supply energy consumption, making it considered the most sustainable and environmentally acceptable denitrification process.

[0003] However, in practical applications, the nitrification process in anaerobic ammonium oxidation (ANAO) often cannot be controlled to an ideal degree, and the nitrate byproducts produced during ANAO also result in limited total nitrogen removal capacity. Summary of the Invention

[0004] The main objective of this invention is to provide a sulfur autotrophic denitrification coupled anaerobic ammonia oxidation biofilm, its construction method, and its application, aiming to solve the problem that existing technologies cannot achieve deep removal of total nitrogen.

[0005] To achieve the above objectives, the present invention provides a method for constructing a sulfur autotrophic denitrification coupled anammox biofilm, comprising the steps of: inoculating a reactor with a mixed sludge composed of sulfur autotrophic denitrification sludge and anammox sludge; wherein, after inoculation, the MLSS of the reactor is 1000-8000 mg / L.

[0006] The mixed sludge is acclimatized in stages to obtain acclimatized sludge.

[0007] Add carrier packing material to the reactor containing the acclimated sludge and run it continuously for more than 30 days to obtain a sulfur autotrophic denitrification coupled anaerobic ammonia oxidation biofilm.

[0008] Furthermore, the phased acclimatization process includes: introducing a first-stage liquid into the reactor, allowing it to remain inside the reactor, and then discharging it; once the accumulation rate of NO2-N in the effluent liquid of the reactor is >50%, proceeding to the next stage.

[0009] The second-stage liquid is introduced into the reactor, remains in the reactor, and then is discharged. Once the NO2-N content in the effluent from the reactor is <10mg / L, it proceeds to the next stage.

[0010] The third-stage liquid is introduced into the reactor and left to stand before being discharged. Once the removal rate of NH4-N in the effluent from the reactor is >75%, the process proceeds to the next stage.

[0011] The first-stage liquid, the second-stage liquid, and the third-stage liquid all contain C sources, N sources, S sources, and trace elements.

[0012] Furthermore, the first-stage liquid, the second-stage liquid, and the third-stage liquid all include NH4-N, NO3-N, and S2O3-S; in the first-stage liquid, the concentration ratio of NH4-N to NO3-N is 1:1, and the concentrations of both NH4-N and NO3-N are 40–60 mg / L; the concentration of S2O3-S is 60–75 mg / L.

[0013] In the second stage liquid, the concentration of NH4-N is the same as that in the first stage liquid; the concentration ratio of NH4-N to NO3-N is 1:2; and the concentration of S2O3-S is the same as that in the first stage liquid.

[0014] In the third-stage liquid, the concentration ratio of NH4-N to that of NH4-N in the second-stage liquid is 3:2; the concentration of NO3-N is the same as that of NO3-N in the second-stage liquid; and the concentration ratio of S2O3-S to that of S2O3-S in the second-stage liquid is 2:1.

[0015] Furthermore, the hydraulic retention time for the sulfur autotrophic denitrification start-up stage, the anaerobic ammonia oxidation start-up stage, and the sulfur autotrophic denitrification and anaerobic ammonia oxidation symbiotic stage is 24 hours.

[0016] The dissolved oxygen in the first stage liquid, the second stage liquid, and the third stage liquid is all less than 0.2 mg / L.

[0017] Furthermore, the biomass ratio of the sulfur autotrophic denitrification sludge to the anaerobic ammonia oxidation sludge is 1:4-5.

[0018] Furthermore, the abundance of sulfur-autotrophic denitrifying functional bacteria in the sulfur-autotrophic denitrifying sludge is >10%; and the abundance of anaerobic ammonia-oxidizing functional bacteria in the anaerobic ammonia-oxidizing sludge is >5%.

[0019] Furthermore, the filling ratio of the carrier filler is 15-30%.

[0020] Furthermore, the carrier packing material includes one or more of the following: non-woven fabric packing, polyurethane foam packing, MBBR packing, suspended ball packing, fiber ball packing, activated carbon packing, volcanic rock packing, and ceramsite packing.

[0021] The present invention also provides a sulfur autotrophic denitrification coupled anaerobic ammonia oxidation biofilm constructed by the construction method described in any of the preceding claims.

[0022] The present invention also provides an application of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation biofilm as described above, or the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation biofilm constructed by the construction method described in any of the preceding claims, in the process of wastewater denitrification treatment.

[0023] The beneficial effects achieved by this invention are as follows:

[0024] The present invention provides a method for constructing a sulfur autotrophic denitrification coupled anammox biofilm. This method involves inoculating a reactor with a mixed sludge (MLSS of 1000–8000 mg / L) composed of sulfur autotrophic denitrification sludge and anammox sludge. The mixed sludge is then acclimated in stages to initiate both the sulfur autotrophic denitrification and anammox processes, rapidly achieving cross-trophy between the two nitrogen removal processes, resulting in acclimated sludge. Carrier packing material is then added to the reactor containing the acclimated sludge, and the reactor is continuously operated for more than 30 days to obtain the sulfur autotrophic denitrification coupled anammox biofilm. This construction method is convenient, easy to operate, and has a simple process flow.

[0025] The sulfur-autotrophic denitrifying bacteria in the obtained sulfur-autotrophic denitrification coupled anammox biofilm can stably provide nitrite for the anammox process, maintain anammox activity, and remove nitrate, a byproduct of anammox, achieving deep removal of total nitrogen and solving the problem of difficult deep removal of total nitrogen in existing technologies. This biofilm can be directly inoculated into any anaerobic reactor under suitable substrate conditions, enabling stable interaction between autotrophic denitrification and anammox, enhancing total nitrogen removal performance, and possessing strong practical engineering application capabilities. Attached Figure Description

[0026] 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 the structures shown in these drawings without creative effort.

[0027] Figure 1 This is a graph showing the changes in nitrogen content in the reactor effluent during the phased acclimatization process in Example 1 of the present invention.

[0028] Figure 2 This is a photograph of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation biofilm constructed in Example 1 of the present invention.

[0029] Figure 3 This is a 16S microbial diversity analysis diagram of the sulfur autotrophic denitrification coupled anaerobic ammonia oxidation biofilm constructed in Example 1 of the present invention;

[0030] Figure 4 This is a diagram showing the nitrogen removal efficiency of the sulfur autotrophic denitrification coupled with anaerobic ammonia oxidation biofilm in Example 2 of the present invention.

[0031] The realization of the objective, functional characteristics and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. It should also be understood that the terminology used in the embodiments of this invention is for describing specific implementations and not for limiting the scope of protection of this invention.

[0034] Unless otherwise defined, all technical and scientific terms used in this invention are consistent with the prior art known to those skilled in the art and the description of this invention. This invention may also be implemented using any prior art methods, devices and materials similar to or equivalent to those described, used or made by means of methods, devices and materials in the embodiments of this invention.

[0035] When numerical ranges are given in the examples, it should be understood that, unless otherwise stated in the invention, both endpoints of each range and any value between the two endpoints may be used. Test methods in the following examples that do not specify specific conditions are generally performed under conventional conditions or as recommended by the respective manufacturers. Unless otherwise specified, all materials or reagents required in the following examples are commercially available.

[0036] The study revealed that anammox requires sufficient nitrite (NO2-N) as a substrate for practical applications. However, the nitrification process is often not ideally controlled in practice, making it susceptible to inhibition by insufficient nitrite content and resulting in unstable total nitrogen removal capacity. Furthermore, anammox alone cannot achieve deep total nitrogen removal because it produces a certain amount of nitrate byproducts, limiting its overall removal capacity. In other words, anammox requires sufficient nitrite as an electron acceptor, and therefore is often combined with short-cut nitrification or short-cut denitrification processes. However, because anammox requires a relatively fixed ratio of ammonia nitrogen (NH4-N) to nitrite substrate, and dissolved oxygen is difficult to precisely control in practice, the nitrification process often cannot achieve ideal control.

[0037] Furthermore, sulfur autotrophic denitrification utilizes the metabolic characteristics of denitrifying bacteria such as Thiobacillus denitrifications, using reduced sulfur compounds as electron donors and NO as the active ingredient. 3- or NO 2- As electron acceptors, they engage in hypoxic or anaerobic physiological activities. Experiments revealed that, based on the chemoautotrophic characteristics of sulfur-autotrophic denitrifying bacteria, coupling them with anaerobic ammonium oxidation (ANAO) can stably provide the nitrite required for ANAO while simultaneously removing the byproduct nitrate, thus improving the total nitrogen removal efficiency of the system. However, both sulfur-autotrophic denitrification and ANAO utilize nitrite as a reaction substrate, indicating a certain degree of competition between the two processes, making stable interaction difficult.

[0038] To address the limitations of existing technologies in achieving deep total nitrogen removal, this invention provides a method for constructing a sulfur autotrophic denitrification coupled with anaerobic ammonium oxidation (AMO) biofilm. The method includes the following steps: inoculating a reactor with a mixed sludge consisting of sulfur autotrophic denitrification sludge and AMO sludge; wherein the MLSS (molecularly suspended solids) in the reactor after inoculation is 1000–8000 mg / L. Specifically, when the sludge concentration (MLSS in the reactor after inoculation) > 8000 mg / L, reactor control becomes difficult; furthermore, during the subsequent phased acclimatization process, a significant amount of dead bacteria may occur, leading to increased organic matter production and promoting heterotrophic bacterial growth, thus affecting system stability. Conversely, if the sludge concentration < 1000 mg / L, problems such as poor nitrogen removal performance and slow biofilm formation may occur.

[0039] The mixed sludge is acclimated in stages to obtain acclimated sludge. Carrier packing material is added to a reactor containing the acclimated sludge, and the reactor is run continuously for more than 30 days to obtain a sulfur autotrophic denitrification coupled anaerobic ammonium oxidation biofilm. Specifically, when the reactor containing the acclimated sludge and carrier packing material is run continuously for more than 30 days, the sulfur autotrophic denitrification coupled anaerobic ammonium oxidation biofilm obtained in this system reaches a relatively stable state and is tightly attached and not easily detached.

[0040] The present invention provides a method for constructing a sulfur autotrophic denitrification coupled anammox biofilm. This method involves inoculating a reactor with a mixed sludge (MLSS of 1000–8000 mg / L) composed of sulfur autotrophic denitrification sludge and anammox sludge. The mixed sludge is then acclimated in stages to initiate both the sulfur autotrophic denitrification and anammox processes, rapidly achieving cross-trophy between the two nitrogen removal processes, resulting in acclimated sludge. Carrier packing material is then added to the reactor containing the acclimated sludge, and the reactor is continuously operated for more than 30 days to obtain the sulfur autotrophic denitrification coupled anammox biofilm. This construction method is convenient, easy to operate, and has a simple process flow.

[0041] Further, the phased acclimation process includes: introducing the first-stage liquid into the reactor, allowing it to remain inside for a period of time, and then discharging it. Once the accumulation rate of NO2-N in the reactor effluent is >50%, the process proceeds to the next stage. Specifically, this stage is the sulfur autotrophic denitrification start-up stage. The process involves introducing the first-stage liquid into the reactor once, allowing it to remain for a period of time, and then discharging it. This cycle of introducing and discharging liquid is repeated multiple times until the accumulation rate of NO2-N in the reactor effluent is >50%, ending this sulfur autotrophic denitrification start-up stage. In this stage, sulfur autotrophic denitrification first reduces nitrate nitrogen (NO3-N) to nitrite nitrogen (NO2-N). Therefore, the nitrite nitrogen content is a key indicator of the activity of the sulfur autotrophic denitrification process. This acclimation stage can rapidly initiate the denitrification process, providing the system with sufficient nitrite nitrogen to initiate the anaerobic ammonium oxidation process. When the nitrite nitrogen content reaches 50% or higher, the activity requirements of the sulfur autotrophic denitrification process are met, and the process proceeds to the next stage.

[0042] The second-stage liquid is introduced into the reactor, held for a period, and then discharged. Once the NO2-N content in the effluent is <10 mg / L, the next stage begins. Specifically, this stage is the anaerobic ammonia oxidation (AAO) start-up stage. After the sulfur autotrophic denitrification start-up stage, the second-stage liquid is introduced into the reactor once, held for a period, and then discharged. This cycle of introduction and discharge is repeated multiple times until the NO2-N content in the effluent is <10 mg / L, ending the AAO start-up stage. The nitrite nitrogen accumulated during the sulfur autotrophic denitrification start-up stage will be consumed by the AAO process occurring in this AAO start-up stage. When the AAO activity is high, the nitrite nitrogen level will decrease to a lower level; that is, when the nitrite nitrogen in the effluent is below 10 mg / L, AAO begins to function stably.

[0043] The third-stage liquid is introduced into the reactor, held for a period, and then discharged. Once the NH4-N removal rate in the reactor effluent exceeds 75%, the process proceeds to the next stage. Specifically, this stage is a symbiotic stage of sulfur autotrophic denitrification and anaerobic ammonium oxidation. After the anaerobic ammonium oxidation start-up stage, the third-stage liquid is introduced into the reactor once, held for a period, and then discharged. This cycle of introduction and discharge is repeated multiple times until the NH4-N removal rate in the reactor effluent exceeds 75%, ending this symbiotic stage of sulfur autotrophic denitrification and anaerobic ammonium oxidation. Since the nitrite nitrogen required for the anaerobic ammonium oxidation reaction is provided by the denitrification process, and the denitrification process itself also consumes nitrite nitrogen, there is competition between it and the anaerobic ammonium oxidation process. Therefore, when the anaerobic ammonium oxidation process dominates in the competition for nitrite nitrogen, the more active anaerobic ammonium oxidation process leads to a large-scale removal of ammonia nitrogen (NH4-N) by anaerobic ammonium oxidation. Conversely, a low ammonia nitrogen removal rate indicates that denitrification is dominant in the competition, and anaerobic ammonia oxidation is inhibited, resulting in a low ammonia nitrogen removal rate. Therefore, ammonia nitrogen content is an indicator of the stability of the system's interaction. When the ammonia nitrogen removal rate in the effluent is >75%, the stable interaction between sulfur autotrophic denitrification and anaerobic ammonia oxidation can be achieved precisely during the symbiotic stage.

[0044] The first-stage liquid, the second-stage liquid, and the third-stage liquid all contain C sources, N sources, S sources, and trace elements.

[0045] Furthermore, the first-stage liquid, the second-stage liquid, and the third-stage liquid all contain NH4-N, NO3-N, and S2O3-S. Specifically, NH4-N and NO3-N can serve as substrates for sulfur autotrophic denitrification and anaerobic ammonium oxidation processes, and using these two components as substrates makes it easier to achieve the interaction between the two processes; S2O3-S can serve as an electron donor for denitrification to obtain a faster reaction rate.

[0046] In the first-stage liquid, the concentration ratio of NH4-N to NO3-N is 1:1, and the concentrations of both NH4-N and NO3-N are 40–60 mg / L; the concentration of S2O3-S is 60–75 mg / L. Preferably, in the first-stage liquid, the concentrations of NH4-N and NO3-N are 50 mg / L; the concentration of S2O3-S is 67.5 mg / L.

[0047] In the second-stage liquid, the concentration of NH4-N is the same as that in the first-stage liquid; the concentration ratio of NH4-N to NO3-N is 1:2; and the concentration of S2O3-S is the same as that in the first-stage liquid. Preferably, in the second-stage liquid, the concentration of NH4-N is 50 mg / L; the concentration of NO3-N is 100 mg / L; and the concentration of S2O3-S is 67.5 mg / L.

[0048] In the third-stage liquid, the concentration ratio of NH4-N to that in the second-stage liquid is 3:2; the concentration of NO3-N is the same as that in the second-stage liquid; and the concentration ratio of S2O3-S to that in the second-stage liquid is 2:1. Preferably, in the third-stage liquid, the concentration of NH4-N is 75 mg / L; the concentration of NO3-N is 100 mg / L; and the concentration of S2O3-S is 135 mg / L.

[0049] Following the above component ratios for a three-stage acclimatization process is beneficial for achieving the interaction between sulfur autotrophic denitrification and anaerobic ammonium oxidation. If the component ratios are too high or too low, one of the microorganisms may be inhibited in the competition, which is detrimental to the overall reactivity.

[0050] Furthermore, the hydraulic retention time for the sulfur autotrophic denitrification start-up stage, the anaerobic ammonia oxidation start-up stage, and the sulfur autotrophic denitrification and anaerobic ammonia oxidation symbiotic stage is 24 hours.

[0051] The dissolved oxygen levels in the first, second, and third stage liquids were all less than 0.2 mg / L.

[0052] Furthermore, the biomass ratio of sulfur autotrophic denitrification sludge to anammox sludge is 1:4–5. This ratio is the optimal range for achieving stable interaction; a biomass ratio outside this range may affect the overall nitrogen removal activity of the system or lead to poor performance of certain processes.

[0053] Furthermore, the abundance of sulfur-autotrophic denitrifying bacteria in sulfur-autotrophic denitrifying sludge is >10%; the abundance of anaerobic ammonia-oxidizing bacteria in anaerobic ammonia-oxidizing sludge is >5%. When the abundance of sulfur-autotrophic denitrifying bacteria or anaerobic ammonia-oxidizing bacteria is too low, it will affect the acclimatization effect, prolong the acclimatization time, and increase the cost.

[0054] Furthermore, the carrier packing material filling ratio is 15-30%. When the carrier packing material filling ratio is <15%, the amount of sulfur autotrophic denitrification coupled with anaerobic ammonia oxidation biofilm obtained is small due to the limited growth space provided by a single carrier. When the carrier packing material filling ratio is >30%, it will result in a low biomass of a single sulfur autotrophic denitrification coupled with anaerobic ammonia oxidation biofilm.

[0055] Furthermore, the types of carrier packing include one or more of the following: non-woven fabric packing, polyurethane foam packing, MBBR packing, suspended ball packing, fiber ball packing, activated carbon packing, volcanic rock packing, and ceramsite packing.

[0056] The present invention also provides a sulfur autotrophic denitrification coupled anaerobic ammonia oxidation biofilm constructed by any of the above methods.

[0057] This invention also provides a sulfur autotrophic denitrification coupled with anaerobic ammonium oxidation (AMO) biofilm as described above, or a sulfur autotrophic denitrification coupled with AMO biofilm constructed by any of the above methods. Specifically, nitrogen-containing pollutant water (containing a matrix of NH4-N, NO3-N, S2O3-S, and KHCO3) can be added to a reactor containing the sulfur autotrophic denitrification coupled with AMO biofilm for wastewater denitrification treatment. After 10 hours of treatment, the total nitrogen removal rate of the nitrogen-containing pollutant water can reach over 88%, and the denitrification efficiency of the biofilm can reach 0.4 mg N / h. -1 / or more.

[0058] The sulfur-autotrophic denitrification coupled with anaerobic ammonia oxidation (AMO) biofilm contains sulfur-autotrophic denitrifying bacteria that stably provide nitrite for the AMO process, maintaining its activity and removing nitrate, a byproduct of AMO, thus achieving deep total nitrogen removal and solving the problem of insufficient deep total nitrogen removal in existing technologies. This biofilm can be directly inoculated into any anaerobic reactor under suitable substrate conditions, enabling stable interaction between autotrophic denitrification and AMO, enhancing total nitrogen removal performance, and demonstrating strong practical engineering application capabilities.

[0059] To further illustrate the present invention, the following examples are provided:

[0060] Example 1

[0061] Sulfate autotrophic denitrification sludge (functional bacterial abundance 50.93%) and anaerobic ammonia oxidation sludge (functional bacterial abundance 17.37%) were mixed and inoculated into an SBR reactor with an effective volume of 4L at a biomass ratio of 1:5. After inoculation, the MLSS of the SBR reactor was 4895 mg / L, and mixed sludge to be acclimated was obtained in the reactor.

[0062] The mixed sludge was acclimated in stages. In the first stage (the start-up stage of sulfur autotrophic denitrification), the influent concentrations of NH4-N, NO3-N, and S2O3-S were 50 mg / L, 50 mg / L, and 67.5 mg / L, respectively, for 5 days. In the second stage (the start-up stage of anaerobic ammonia oxidation), the influent concentrations of NH4-N, NO3-N, and S2O3-S were 50 mg / L, 100 mg / L, and 67.5 mg / L, respectively, for 5 days. In the third stage (the symbiotic stage of sulfur autotrophic denitrification and anaerobic ammonia oxidation), the influent concentrations of NH4-N, NO3-N, and S2O3-S were 75 mg / L, 100 mg / L, and 135 mg / L, respectively, for 9 days. The hydraulic retention time (HRT) was maintained at 24 h throughout all three stages, and the dissolved oxygen (DO) was <0.2, resulting in acclimated sludge.

[0063] A sulfur-autotrophic denitrification coupled with anaerobic ammonia oxidation biofilm was obtained after adding polyurethane foam carrier packing to an SBR reactor containing acclimated sludge, with a carrier filling ratio of 25%, and operating continuously for 45 days under the following conditions: influent NH4-N, NO3-N and S2O3-S of 75 mg / L, 100 mg / L and 135 mg / L respectively, DO < 0.2, HRT = 24 h, and temperature of 30 ± 5 ℃.

[0064] The graph shows the changes in nitrogen content in the reactor effluent during the phased acclimatization process. Figure 1 As shown. According to Figure 1The results showed that the NO2-N accumulation rate in the effluent gradually increased during the first stage (0-5 days), indicating that the sulfur autotrophic denitrification activity gradually increased during this stage. NO2-N accumulation is determined by the characteristics of the sulfur autotrophic denitrification process, as the reduction rate of NO3-N to NO2-N is much higher than that of NO2-N to N2. Therefore, under insufficient sulfur source conditions, a certain amount of NO2-N accumulation occurs, providing substrate conditions for the initiation of the anaerobic ammonium oxidation process. During the second stage (6-10 days), the effluent NO2-N content gradually decreased. This is because after increasing the influent NO3-N concentration, the system produced sufficient NO2-N, while the lower S2O3-S content limited the consumption of NO2-N by the denitrification process. At this time, the anaerobic ammonium oxidation activity gradually increased, and the effluent NH4-N continued to decrease. In the third stage (days 11-19), after increasing the concentrations of NH4-N and S2O3-S in the influent, the sulfur autotrophic denitrification and anaerobic ammonium oxidation processes were simultaneously enhanced. The NH4-N removal rate gradually increased, indicating that anaerobic ammonium oxidation gradually became dominant in the system. Sulfotrophic denitrification was mainly responsible for continuously providing NO2-N as a reaction substrate for anaerobic ammonium oxidation and removing NO3-N, a byproduct of the anaerobic ammonium oxidation process. The two denitrification microbial symbiotic systems gradually formed.

[0065] Actual photograph of the obtained sulfur autotrophic denitrification coupled anaerobic ammonium oxidation biofilm is shown below. Figure 2 As shown. From Figure 2 As can be seen, the microorganisms in the biofilm are uniformly attached, aggregated, and spread throughout the entire carrier, indicating that sulfur autotrophic denitrifying and anaerobic ammonia oxidizing bacteria grow in large quantities in the biofilm.

[0066] 16S microbial diversity analysis was performed on this sulfur autotrophic denitrification coupled anaerobic ammonia oxidation biofilm. The results are as follows: Figure 3 As shown. According to Figure 3 Observations show that the biofilm contains 6.14% Candidatus_Kuenenia (anaerobic ammonia oxidizing bacteria) and 9.82% Hydrogenophilaceae and Thiobacillus (thiobacillus), two sulfur autotrophic denitrifying bacteria, respectively. Both types of functional microorganisms are present in relatively abundant amounts.

[0067] Example 2

[0068] Three pre-constructed sulfur-autotrophic denitrification coupled anaerobic ammonium oxidation biofilms were taken from the reactor of Example 1 and placed in 250 ml anaerobic flasks. A substrate containing 25 mg / L NH4-N, 35 mg / L NO3-N, 75 mg / L S2O3-S, and 50 mg / L KHCO3 was added. The biofilms were cultured at 30°C, 120 rpm, and DO < 0.2 mg / L for 10 h, with samples taken every 2 h for analysis.

[0069] Specific nitrogen removal efficiency, such as Figure 4 As shown. According to Figure 4 The results showed that the biofilm denitrification process exhibited a distinct metabolic characteristic of sulfur autotrophic denitrification coupled with anaerobic ammonium oxidation. Sulfotrophic denitrification dominated in the initial stage of the reaction, with NO3-N being rapidly reduced within 0–2 h, reaching a peak NO2-N concentration. Subsequently, anaerobic ammonium oxidation became dominant, with NO2-N and NH4-N concentrations gradually decreasing, while sulfur autotrophic denitrification continued, keeping NO3-N at a stable low level. After 10 h, the total nitrogen removal rate of the biofilm reached 88.79%, and the biofilm denitrification rate was 0.45 mg N / h. -1 / each, demonstrating high total nitrogen removal performance.

[0070] In summary, the above-described technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for constructing a sulfur autotrophic denitrification coupled with anaerobic ammonia oxidation biofilm, characterized in that, The method comprises the steps of: inoculating mixed sludge composed of sulfur autotrophic denitrification sludge and anaerobic ammonia oxidation sludge in a reactor; wherein the MLSS of the reactor after inoculation is 1000-8000 mg / L; carrying out phased acclimation on the mixed sludge to obtain acclimated sludge; adding carrier filler to the reactor containing the acclimated sludge and continuously operating for more than 30 days to obtain sulfur autotrophic denitrification coupled anaerobic ammonia oxidation biofilm; the phased acclimation comprises in sequence: sulfur autotrophic denitrification start-up phase: feeding first-stage liquid into the reactor, discharging after residence in the reactor, and entering the next phase when the accumulation rate of NO2-N in the effluent liquid of the reactor is >50%; anaerobic ammonia oxidation start-up phase: feeding second-stage liquid into the reactor, discharging after residence in the reactor, and entering the next phase when the content of NO2-N in the effluent liquid of the reactor is <10 mg / L; sulfur autotrophic denitrification and anaerobic ammonia oxidation mutual nutrition phase: feeding third-stage liquid into the reactor, discharging after residence in the reactor, and entering the next phase when the removal rate of NH4-N in the effluent liquid of the reactor is >75%; wherein the first-stage liquid, the second-stage liquid and the third-stage liquid all comprise C source, N source, S source and trace elements; the first-stage liquid, the second-stage liquid and the third-stage liquid all comprise NH4-N, NO3-N and S2O3-S; in the first-stage liquid, the concentration ratio of NH4-N to NO3-N is 1:1, and the concentrations of NH4-N and NO3-N are both 40-60 mg / L; the concentration of S2O3-S is 60-75 mg / L; in the second-stage liquid, the concentration of NH4-N is consistent with that in the first-stage liquid; the concentration ratio of NH4-N to NO3-N is 1:2; the concentration of S2O3-S is consistent with that in the first-stage liquid; in the third-stage liquid, the concentration ratio of NH4-N to that in the second-stage liquid is 3:2; the concentration of NO3-N is consistent with that in the second-stage liquid; the concentration ratio of S2O3-S to that in the second-stage liquid is 2:

1.

2. The construction method of claim 1, wherein, the hydraulic retention time of the sulfur autotrophic denitrification start-up phase, the anaerobic ammonia oxidation start-up phase and the sulfur autotrophic denitrification and anaerobic ammonia oxidation mutual nutrition phase is all 24 h; the dissolved oxygen of the first-stage liquid, the second-stage liquid and the third-stage liquid is all less than 0.2 mg / L.

3. The construction method of claim 1, wherein, the biomass ratio of the sulfur autotrophic denitrification sludge to the anaerobic ammonia oxidation sludge is 1:4-5.

4. The construction method of claim 1, wherein, the abundance of sulfur autotrophic denitrification functional bacteria in the sulfur autotrophic denitrification sludge is >10%; the abundance of anaerobic ammonia oxidation functional bacteria in the anaerobic ammonia oxidation sludge is >5%.

5. The construction method of claim 1, wherein, the filling ratio of the carrier filler is 15-30%.

6. The construction method of claim 1, wherein, The carrier filler includes one or more of non-woven fabric filler, polyurethane foam filler, MBBR filler, suspended ball filler, fiber ball filler, activated carbon filler, volcanic rock filler, and ceramic filler.

7. A sulfur autotrophic denitrification coupled with ANAMMOX biofilm constructed by the construction method of any one of claims 1-6.

8. Use of the sulfur autotrophic denitrification coupled with ANAMMOX biofilm of claim 7 or the sulfur autotrophic denitrification coupled with ANAMMOX biofilm constructed by the construction method of any one of claims 1-6 in a wastewater denitrification treatment process.

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