An autotrophic nitrogen removal method for wastewater based on an anaerobic ammonia oxidation functional dynamic membrane bioreactor

Abstract

This invention discloses an autotrophic nitrogen removal method for wastewater based on an anaerobic ammonia oxidation functional dynamic membrane bioreactor, belonging to the field of wastewater treatment technology. This invention aims to solve the bottleneck problem of low nitrogen removal efficiency and poor stability in mainstream wastewater due to the lack of functional bacteria and imbalance in bacterial community competition. The method includes the following steps: (1) constructing an anaerobic ammonia oxidation functional dynamic membrane using a nylon fabric membrane as the supporting material. (2) placing the anaerobic ammonia oxidation functional dynamic membrane formed in step (1) in short-cut nitrifying sludge for cultivation, constructing an integrated PN / A-DMBR system. (3) operating the integrated PN / A-DMBR system optimized in step (1). The separate cultivation of different bacterial communities in spatial locations proposed in this invention avoids the problem of imbalance in functional bacterial community competition and elimination of competing bacteria under low ammonia nitrogen conditions, which helps to promote the large-scale application of low-carbon autotrophic nitrogen removal treatment for mainstream municipal wastewater.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a wastewater autotrophic denitrification method based on an anaerobic ammonia oxidation functional dynamic membrane bioreactor. Background Technology

[0002] Anaerobic ammonia oxidation (ANA) autotrophic nitrogen removal technology requires no external carbon source and has low energy consumption, driving the transformation of autotrophic nitrogen removal technology from sidestream municipal wastewater to mainstream wastewater with larger volumes. It represents the forefront of research and work in the field of wastewater treatment under the "dual carbon" background. The integrated short-cut nitrification / anaerobic ammonia oxidation process is one of the most representative autotrophic nitrogen removal processes. The integrated PN / A process couples short-cut nitrification and anaerobic ammonia oxidation in the same system, enhancing the metabolic synergy of aerobic and anaerobic ammonia oxidizing bacteria. Compared with traditional nitrification / denitrification processes, it saves 62.5% of aeration and requires no external carbon source.

[0003] The efficient operation of integrated short-cut nitrification / anaerobic ammonia oxidation processes relies on the synergistic denitrification by aerobic and anaerobic ammonia oxidizing bacteria. However, under low ammonia nitrogen conditions in mainstream wastewater (40-70 mg NH4), + At -N / L, the lack of free ammonia or free nitrite inhibits the activity of competitive nitrite-oxidizing bacteria, which is detrimental to the survival and growth of aerobic ammonia oxidizing bacteria and anaerobic ammonia oxidizing bacteria, which are already difficult to enrich. The doubling cycle is about 10-12 days. In addition, the secretion of bacterial extracellular polymers decreases under low ammonia nitrogen conditions, leading to loose and disintegrated sludge structure and severe loss of functional bacteria. Therefore, the mainstream integrated PN / A process for wastewater treatment has a long start-up time and is difficult to operate stably for a long period of time. Therefore, the key to the stable operation of the mainstream integrated short-cut nitrification / anaerobic ammonia oxidation process for wastewater treatment lies in rapidly enriching autotrophic denitrifying microorganisms and improving the metabolic competitiveness of aerobic and anaerobic ammonia oxidizing bacteria to inhibit the activity of nitrite-oxidizing bacteria, thereby effectively coupling the short-cut nitrification and anaerobic ammonia oxidation processes.

[0004] Dynamic membrane bioreactors use coarse-pore micro-mesh materials with pore sizes of 20-100 μm as the base membrane. Under the influence of osmotic tension and microbial migration and colonization, microorganisms and extracellular polymers accumulate on the surface of the base membrane, forming a dynamic membrane that combines filtration and biofilm properties and retains microorganisms to the maximum extent. Its dynamic membrane solid-liquid separation efficiency is similar to that of microfiltration membranes with an average pore size of 0.1 μm in membrane bioreactors. Moreover, the dynamic membrane has low resistance and high flux, avoiding the drawback of severe membrane fouling in membrane bioreactor systems. Furthermore, the raw materials for membrane modules are cheaper and more readily available than those for membrane bioreactors.

[0005] Dynamic membrane bioreactors (MBRs) not only possess the advantage of maximizing in-situ enrichment of functional bacteria, but also exhibit biofilm properties. They can selectively enrich anaerobic ammonia oxidizing bacteria, achieving spatial separation from aerobic ammonia oxidizing bacteria in the sludge phase to create optimal habitats for each. The osmotic pull generated by filtration weakens mass transfer resistance, driving nutrients to migrate deeper into the functional dynamic membrane. This enhances the nitrogen substrate intertrophic relationship between aerobic and anaerobic ammonia oxidizing bacteria and promotes high-flux metabolic exchange between them. This strengthens their synergistic symbiosis and improves their competitiveness against nitrite oxidizing bacteria, compensating for the difficulty in inhibiting nitrite oxidizing bacteria under low ammonia nitrogen conditions. Therefore, this addresses the problem of low denitrification efficiency and poor stability in mainstream wastewater autotrophic denitrification caused by a lack of functional bacteria and imbalanced microbial competition, making it possible to achieve large-scale and stable application of integrated PN / A processes in mainstream wastewater treatment. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing integrated PN / A processes, which suffer from low denitrification efficiency and poor stability due to the lack of functional bacteria and imbalance of bacterial community competition in autotrophic denitrification.

[0007] To address the aforementioned technological shortcomings, this invention proposes a wastewater autotrophic denitrification method based on an anaerobic ammonia oxidation functional dynamic membrane bioreactor, the specific scheme of which is as follows:

[0008] A wastewater autotrophic denitrification method based on an anaerobic ammonia oxidation functional dynamic membrane bioreactor, the method comprising the following steps:

[0009] (1) Using nylon fabric membrane as support material to construct anaerobic ammonia oxidation functional dynamic membrane, the nylon fabric membrane is placed in the anaerobic ammonia oxidation sludge system for operation and cultivation. The outlet of the nylon fabric membrane component is connected to a suction pump to achieve filtration and effluent. The sludge mixture and volatile suspended solids of the sludge mixture, under the action of filtration and suction, functional bacteria such as anaerobic ammonia oxidation bacteria attach to the nylon fabric membrane, thereby constructing the anaerobic ammonia oxidation functional dynamic membrane.

[0010] (2) Place the anaerobic ammonia oxidation dynamic membrane formed in step (1) into the short-cut nitrification sludge to construct an integrated short-cut nitrification and anaerobic ammonia oxidation dynamic membrane bioreactor system.

[0011] (3) At a pH of 6.7-8.3 and an ammonia nitrogen concentration of 300-500 mg NH4 + -N / L, aeration to shutdown time ratio of 40 / 80 min, and operating membrane flux of 12 L / m³ 2 The integrated short-cut nitrification and anaerobic ammonia oxidation dynamic membrane bioreactor system was operated under parameters of / h. After 15-20 days of trial operation, the system removed nitrogen pollutants.

[0012] An anaerobic ammonia oxidation-based dynamic membrane bioreactor includes: an anaerobic ammonia oxidation-based dynamic membrane, short-cut nitrification flocculent sludge, microporous aeration pipes, a container, and an air inlet channel.

[0013] The anaerobic ammonia oxidation functional dynamic membrane includes a nylon fabric membrane and anaerobic ammonia oxidizing bacteria; the nylon fabric membrane and anaerobic ammonia oxidizing bacteria are disposed in short-cut nitrification flocculent sludge; the short-cut nitrification flocculent sludge is disposed in a container; the air inlet channel is connected to the bottom of the container;

[0014] The anaerobic ammonia-oxidizing bacteria are attached to the nylon fabric membrane.

[0015] Preferably, it also includes: a water outlet tank, a vacuum pressure gauge, and a water outlet pump; the water outlet tank is connected to the container in series with the water outlet pump and the vacuum pressure gauge.

[0016] Preferably, it also includes: a peristaltic pump and a water inlet tank; the water inlet tank is connected to the container via the peristaltic pump.

[0017] Preferably, it further includes: a stirring paddle; the stirring paddle is disposed inside the container and at the bottom of the short-range nitrifying flocculent sludge.

[0018] Preferably, the air intake channel includes a blower and a gas flow meter; the blower is located at the tail end of the air intake channel, and the gas flow meter is located in the air intake channel; the microporous aeration pipe is connected to the air intake channel.

[0019] Preferably, it also includes a water bath partition, a temperature sensor, and a heating rod; the temperature sensor and the heating rod are disposed in the water bath partition.

[0020] Preferably, it also includes a level gauge; the level gauge is disposed on the top of the container.

[0021] The above-mentioned application of dynamic membrane bioreactor based on anaerobic ammonia oxidation in wastewater treatment.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0023] This invention can achieve spatial separation between anaerobic ammonia oxidizing bacteria and aerobic ammonia oxidizing bacteria in sludge by selectively enriching anaerobic ammonia oxidizing bacteria to create their respective optimal habitats. The osmotic pull generated by filtration drives nutrients to migrate to the deep layer of the dynamic membrane of anaerobic ammonia oxidation, which can enhance the intertrophic relationship between anaerobic and aerobic ammonia oxidizing bacteria and nitrogen substrate, thereby strengthening the synergistic symbiotic mechanism and improving competitiveness, and making up for the deficiency of nitrite oxidizing bacteria being difficult to inhibit under low ammonia nitrogen conditions. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0025] Figure 1 This is a graph showing the changes in the total number and relative abundance of anaerobic ammonia-oxidizing dynamic membrane bacteria.

[0026] Figure 2 This diagram illustrates the dynamic membrane formation and integrated PN / A-DMBR reactor for anaerobic ammonia oxidation.

[0027] Figure 3 This diagram shows the functional dynamic membrane formation and integrated PN / A-DMBR device.

[0028] Figure 4 The diagram shows the treatment effect of an integrated PN / A-DMBR system under different influent and operating conditions.

[0029] Figure 5 This is a diagram showing the changes in transmembrane pressure difference in the dynamic membrane of anaerobic ammonia oxidation.

[0030] Figure 3 The components are as follows: 1. Inlet tank; 2. Peristaltic pump; 3. Level gauge; 4. Agitator; 5. Water bath partition; 6. Vacuum pressure gauge; 7. Outlet pump; 8. Outlet tank; 9. Blower; 10. Short-cut nitrification flocculent sludge; 11. Temperature sensor; 12. Heating rod; 13. Microporous aeration pipe; 14. Anaerobic ammonia oxidation dynamic membrane; 15. Gas flow meter. Detailed Implementation

[0031] 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 some embodiments of the present invention, and not all embodiments. 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.

[0032] The present invention will be further described below with reference to implementation examples.

[0033] In this embodiment, the specific components of the simulated urban wastewater are shown in Table 1:

[0034] Table 1 Components of Artificial Water Supply

[0035]

[0036] a Add 0.5 ml of trace element reserve solution to each liter of artificially prepared water.

[0037] Example

[0038] A P based on an anaerobic ammonia oxidation functional dynamic membrane

[0039] A N / A bioreactor was used, employing a nylon fabric membrane as the supporting material for the formation of the anammox functional dynamic membrane. The anammox functional dynamic membrane was optimized and constructed in anammox sludge. This formed anammox functional dynamic membrane was then placed in short-cut nitrification sludge to construct an integrated PN / A-DMBR system. Its long-term stable operation performance in mainstream wastewater treatment was investigated. The method includes the following steps:

[0040] (1) Optimize the formation of an anaerobic ammonia oxidation functional dynamic membrane and construct an integrated PN / A-DMBR system.

[0041] (1-1) A nylon fabric membrane with an average pore size of 20-25 μm was used as the supporting material for the formation of the anaerobic ammonia oxidation functional dynamic membrane. It was placed in a high-abundance anaerobic ammonia oxidation sludge system with a relative abundance of anaerobic ammonia oxidizing bacteria >20%, at a temperature of 35℃, a dissolved oxygen concentration of 1.0 mg / L, and a membrane flux of 10 L / m³. 2 Under the conditions of volatile suspended solids content of sludge mixed liquor of 2500-4500 mg / L, an anaerobic ammonia oxidation functional dynamic membrane was constructed through filtration and suction.

[0042] (1-2) The successful construction of the anaerobic ammonia oxidation functional dynamic membrane was determined by the following three indicators: at 35℃, 300-500 mg NH4 + With ammonia nitrogen level of -N / L, and a hydraulic retention time of 1.5 days, the gene copy number of anaerobic ammonia oxidizing bacteria on the anaerobic ammonia oxidation functional dynamic membrane was detected by Q-PCR to investigate the enrichment and growth of anaerobic ammonia oxidizing bacteria in the integrated PN / A-DMBR system. The enrichment was determined when the abundance of anaerobic ammonia oxidizing bacteria reached a minimum limit of 15%-18%. Changes in the total bacterial count in the effluent filtered by the anaerobic ammonia oxidation functional dynamic membrane were also examined. High-throughput sequencing and other molecular biology techniques were used to investigate changes in microbial diversity and population structure during operation of the anaerobic ammonia oxidation functional dynamic membrane. The enrichment was determined when the total bacterial count in the effluent decreased to 6.38 × 10⁻⁶. 7 The nitrogen removal contribution of the anammox dynamic membrane was analyzed by extracting and detecting the difference in nitrogen pollutant concentration between the sludge mixed liquor and the effluent filtered by the anammox dynamic membrane. The nitrogen removal capacity of the anammox dynamic membrane was measured when its nitrogen removal contribution reached 5.5 ± 0.5% of the total system nitrogen removal. The successful construction of the anammox dynamic membrane was determined by combining the above three indicators. The results of the relative abundance changes of anammox bacteria, the total bacterial count changes in the effluent filtered by the anammox dynamic membrane, and the nitrogen removal contribution of the anammox dynamic membrane during its operation are as follows: Figure 1 And Table 2.

[0043] Table 2 Dynamic Membrane Nitrogen Desorption Contribution of Anaerobic Ammonium Oxidation Function

[0044]

[0045] (2) Place the anaerobic ammonia oxidation functional dynamic membrane formed in step (1) into the short-cut nitrification sludge to construct an integrated PN / A-DMBR system.

[0046] (2-1) The following simulated wastewater components were used as the feed water for the integrated PN / A-DMBR system:

[0047] The water preparation components, in g / L, are: KH₂PO₄ 0.02, CaCl₂ 0.005, MgSO₄ 0.002, KHCO₃ 1.25, FeSO₄·7H₂O 0.015, Na₂EDTA 0.02, and 0.5 mL of trace element stock solution is added per liter of artificially prepared water. The specific components of the stock solution, in g / L, are as follows: Na₂EDTA 7.5, H₃BO₄ 0.035, MnCl₂·4H₂O 0.495, CuSO₄·5H₂O 0.625, ZnSO₄·7H₂O 1.075, NiCl₂·6H₂O 0.475, CoCl₂·6H₂O 0.21, NaMoO₄·2H₂O 0.55, NO₂ - -N 60-550mg / L, NH4 + -N: 40-500mg / L.

[0048] (2-2) The integrated PN / A-DMBR system was started up using a medium-temperature, high-ammonia-nitrogen method at a temperature of 35℃, a dissolved oxygen concentration of 1.0 mg / L, a pH of 6.7-8.3, and an ammonia-nitrogen concentration of 300-500 mg NH4. + The integrated PN / A-DMBR system was operated under conditions of -N / L, with an aeration-to-stop time ratio of 40 / 80 min and an operating membrane flux of 12 L / m³. 2 Operating the system with parameters set at / h is beneficial for achieving optimal nitrogen pollution removal. After 15-20 days of trial operation, the system was able to stably and efficiently remove nitrogen pollutants, with a denitrification efficiency of approximately 83%, demonstrating the successful construction and efficient operation of the integrated PN / A-DMBR system. The dynamic membrane formation of anaerobic ammonia oxidation and the integrated PN / A-DMBR reactor are as follows. Figure 2 As shown:

[0049] Comparative Example

[0050] The integrated PN / A-DMBR system demonstrates excellent denitrification performance for different types of wastewater.

[0051] At 35℃, 300-500mg NH4 + High ammonia nitrogen (300-500 mg NH4) -N / L + -N / L), at room temperature (20℃), 300-500 mg NH4 + High ammonia nitrogen concentration of -N / L, and at room temperature (20℃), 40-70 mg NH4 + Under low ammonia nitrogen conditions (-N / L), an integrated PN / A-DMBR system was operated using simulated artificial water distribution. The dissolved oxygen concentration was 0.3-0.6 mg / L, aeration / anoxic time was 40 / 80 min, with 3 aeration / anoxic cycles and an 8-hour cycle. The total nitrogen removal load (TNRR, kgN / m³) of the integrated PN / A-DMBR system was measured and analyzed. 3 / d), total nitrogen removal rate (TNRE, %), and ammonia oxidation rate of anaerobic ammonia oxidizing bacteria (AOR, gN / m³). 3 / h), to investigate the nitrogen removal performance of the integrated PN / A-DMBR system. Among them:

[0052]

[0053] The operating results of the integrated PN / A-DMBR system under three different conditions are as follows: Figure 4 As shown:

[0054] The results of the integrated PN / A-DMBR system under three different influent and operating conditions lead to the conclusion that the integrated PN / A-DMBR system can stably and efficiently remove nitrogen in the long term under medium and normal temperature conditions, even when the influent contains high and low concentrations of nitrogen pollutants.

[0055] (3) Functional monitoring and maintenance of the anaerobic ammonia oxidation dynamic membrane in the integrated PN / A-DMBR system (3-1) The integrated PN / A-DMBR system optimized in operation step (1) was examined for the abundance of aerobic ammonia oxidizing bacteria in suspended sludge and the abundance of anaerobic ammonia oxidizing bacteria in the anaerobic ammonia oxidation dynamic membrane during the stable operation period. The abundance of aerobic ammonia oxidizing bacteria and anaerobic ammonia oxidizing bacteria were maintained at 15±5% and 25±5%, respectively, indicating that the functional microbial structure of the integrated PN / A-DMBR system was stable and the denitrification capacity was strong.

[0056] (3-2) The transmembrane pressure difference of the anammox dynamic membrane continuously increases with the operation process. When the TMP reaches 35-40 kPa, membrane fouling cleaning of the anammox dynamic membrane is required. Physical scraping can restore the TMP to below 15 kPa, achieving a better membrane fouling removal effect. The change of transmembrane pressure difference of the anammox dynamic membrane during the operation of the integrated PN / A-DMBR system is as follows: Figure 5 :

[0057] (3-3) Investigate the change in the abundance of anaerobic ammonia oxidation bacteria in the dynamic membrane with the operation process. When it reaches the minimum abundance limit of 10%, the dynamic membrane with anaerobic ammonia oxidation function needs to be placed in anaerobic ammonia oxidation sludge for operation and cultivation, so as to restore the anaerobic ammonia oxidation function of the dynamic membrane. The restoration method is the same as that described in (1-1).

[0058] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0059] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A wastewater autotrophic denitrification method based on an anaerobic ammonia oxidation functional dynamic membrane bioreactor, characterized in that, The method includes the following steps: (1) Using nylon fabric membrane as support material to construct anaerobic ammonia oxidation functional dynamic membrane, the nylon fabric membrane is placed in the anaerobic ammonia oxidation sludge system for operation and cultivation. The outlet of the nylon fabric membrane component is connected to a suction pump to achieve filtration and effluent. The sludge mixture and volatile suspended solids of the sludge mixture are attached to the nylon fabric membrane by anaerobic ammonia oxidation bacteria under the action of filtration and suction, thereby constructing the anaerobic ammonia oxidation functional dynamic membrane. (2) Place the anaerobic ammonia oxidation functional dynamic membrane formed in step (1) into the short-cut nitrification flocculent sludge to construct an integrated short-cut nitrification and anaerobic ammonia oxidation dynamic membrane bioreactor system; achieve spatial separation between anaerobic ammonia oxidizing bacteria and aerobic ammonia oxidizing bacteria in the sludge phase by selectively enriching anaerobic ammonia oxidizing bacteria to create their respective optimal habitats. (3) The pH value is 6.7-8.3, the ammonia nitrogen concentration is 300-500 mg N / L, the aeration to shutdown time ratio is 40 / 80 min, and the operating membrane flux is 12 L / m. 2 The integrated short-cut nitrification and anaerobic ammonia oxidation dynamic membrane bioreactor system was operated at a parameter of / h. After 15-20 days of trial operation, the system removed nitrogen pollutants. The osmotic pull generated by filtration drove nutrients to migrate to the deep layer of the anaerobic ammonia oxidation functional dynamic membrane, which could strengthen the mutual nutrition of nitrogen substrate between anaerobic ammonia oxidizing bacteria and aerobic ammonia oxidizing bacteria, thereby enhancing the synergistic symbiotic mechanism and improving competitiveness.

2. The wastewater autotrophic denitrification method based on an anaerobic ammonia oxidation functional dynamic membrane bioreactor according to claim 1, characterized in that, The anaerobic ammonia oxidation functional dynamic membrane bioreactor includes: an anaerobic ammonia oxidation functional dynamic membrane, short-cut nitrification flocculent sludge, microporous aeration pipes, a container, and an air inlet channel. The anaerobic ammonia oxidation functional dynamic membrane includes a nylon fabric membrane and anaerobic ammonia oxidizing bacteria; the nylon fabric membrane and anaerobic ammonia oxidizing bacteria are disposed in short-cut nitrification flocculent sludge; the short-cut nitrification flocculent sludge is disposed in a container; the air inlet channel is connected to the bottom of the container; The anaerobic ammonia-oxidizing bacteria are attached to the nylon fabric membrane.

3. The wastewater autotrophic denitrification method based on an anaerobic ammonia oxidation functional dynamic membrane bioreactor according to claim 2, characterized in that, Also includes: The water outlet tank, vacuum pressure gauge, and water outlet pump are connected in series to the container via the water outlet pump and vacuum pressure gauge.

4. The wastewater autotrophic denitrification method based on an anaerobic ammonia oxidation functional dynamic membrane bioreactor according to claim 2, characterized in that, Also includes: A peristaltic pump and a water inlet tank; the water inlet tank is connected to the container via the peristaltic pump.

5. The wastewater autotrophic denitrification method based on an anaerobic ammonia oxidation functional dynamic membrane bioreactor according to claim 2, characterized in that, Also includes: A stirring paddle; the stirring paddle is disposed inside the container and at the bottom of the short-range nitrifying flocculent sludge.

6. The wastewater autotrophic denitrification method based on an anaerobic ammonia oxidation functional dynamic membrane bioreactor according to claim 2, characterized in that, The air intake channel includes a blower and a gas flow meter; the blower is located at the tail end of the air intake channel, and the gas flow meter is located in the air intake channel; the microporous aeration pipe is connected to the air intake channel.

7. The wastewater autotrophic denitrification method based on an anaerobic ammonia oxidation functional dynamic membrane bioreactor according to claim 2, characterized in that, It also includes a water bath partition, a temperature sensor, and a heating rod; the temperature sensor and the heating rod are disposed in the water bath partition.

8. The wastewater autotrophic denitrification method based on an anaerobic ammonia oxidation functional dynamic membrane bioreactor according to claim 2, characterized in that, It also includes a level gauge; the level gauge is located on top of the container.

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