Anaerobic ammonium oxidation bacteria enrichment culture and high ammonia nitrogen wastewater denitrification process

Abstract

The invention belongs to the technical field of environmental engineering, and particularly relates to an anaerobic ammonium oxidation bacteria enrichment culture and high-ammonia-nitrogen wastewater denitrification process which comprises the following steps: (1) preparing a functional carrier; (2) pretreating a functional carrier; (3) preparing an anaerobic bacteria enrichment carrier; (4) pretreating the high-ammonia-nitrogen wastewater; and (5) carrying out denitrification reaction. The scheme is suitable for high-ammonia-nitrogen wastewater treatment, and the starting rate, the operation stability, the treatment efficiency and the long-term economy of the process are improved through the design of the structure and the function of the functional carrier.

Description

Technical Field

[0001] This invention belongs to the field of environmental engineering technology, specifically relating to the enrichment and cultivation of anaerobic ammonia-oxidizing bacteria and the denitrification process for high ammonia nitrogen wastewater. Background Technology

[0002] The treatment of high-concentration nitrogen-containing wastewater is a crucial issue in the current environmental protection field. Traditional nitrification-denitrification processes suffer from high energy consumption, the need for carbon source addition, and large sludge production. In contrast, anaerobic ammonia oxidation (ANAO) offers advantages such as no need for external carbon sources, low aeration rates, and low sludge yield, and is considered a promising next-generation nitrogen removal technology. However, the slow growth and environmental sensitivity of ANAO bacteria make efficient enrichment and maintenance a key bottleneck in the engineering application of this process.

[0003] Existing technologies primarily employ microbial immobilization schemes, with biofilm reactors based on functional carriers being the mainstream technological approach. For example, patent CN105925478B adds specific packing material to anaerobic membrane bioreactors, providing support for microbial attachment and mitigating membrane fouling through mechanical friction. However, this type of carrier design, guided by physical structure optimization, has inherent drawbacks: as a static, passive attachment framework, it lacks the ability to actively regulate the complex physiological and ecological needs of the microbial community. When treating complex industrial wastewater, it cannot provide the necessary microenvironmental buffer for the microbial community, resulting in insufficient process robustness.

[0004] To compensate for the lack of biofunctionality in physical carriers, subsequent research has shifted towards introducing bioactive or chemically functional components. Patent CN111479782B proposes a carrier containing carbon particles, utilizing the biocompatibility of carbon materials to accelerate process start-up. However, this technology primarily focuses on the start-up phase, insufficiently considering the challenges of the stable operation and aging / decline phases. It also lacks a systematic integration of functions such as ammonia nitrogen adsorption and slow release, pH buffering, and trace element supplementation, and is devoid of carrier regeneration strategies.

[0005] During the freezing process of a mixed solution of chitosan and sodium alginate, the solvent water crystallizes to form ice crystals, while the polymer chains are displaced into the interstitial spaces of the ice crystals and undergo physical cross-linking to form a network structure. Subsequently, in the freeze-drying stage, the ice crystals are removed through sublimation, leaving the porous structure corresponding to the ice crystal template. The size and morphology of the ice crystals determine the pore size and porosity of the final material, while factors such as the concentration of the polymer, the freezing rate, and the chitosan / sodium alginate ratio collectively regulate the morphology of the pore structure. Rapid freezing forms small and uniform micropores, while slow freezing produces larger interconnected channels. In addition, the electrostatic interaction between the two polyelectrolytes can enhance the stability of the framework, and the degree of cross-linking or the addition of cross-linking agents (such as Ca2+) can further improve the stability of the framework. 2+ The mechanical properties of the pore structure can be further optimized. The resulting porous material has high porosity, three-dimensional interconnected channels, and an adjustable pore size distribution.

[0006] Existing technologies employ static, single-function carrier designs to address the dynamic, multi-stage needs of microbial ecosystems. The entire anaerobic ammonia oxidation process includes multiple stages such as strain attachment and activation, adaptive acclimatization, efficient metabolism, shock load response, and carrier regeneration, each with varying functional requirements for the carrier. Existing technologies either emphasize physical structure or enhance a single function, failing to provide a comprehensive solution that meets the needs of the entire microbial community lifecycle.

[0007] Therefore, it is urgent to break through the traditional static carrier framework, develop a functional carrier that integrates high efficiency, stability, and environmental buffering, and a coordinated control scheme to promote the large-scale industrial application of anaerobic ammonia oxidation technology. Summary of the Invention

[0008] This invention belongs to the field of wastewater biological treatment technology, and more specifically, it relates to a method for enriching and cultivating anaerobic ammonia-oxidizing bacteria and a corresponding denitrification process, which is suitable for the treatment of high ammonia nitrogen wastewater. Through the design of the structure and function of the functional carrier, the start-up rate, operational stability, treatment efficiency and long-term economic benefits of the process are improved.

[0009] Specifically, the technical solution disclosed in this invention, the anaerobic ammonia-oxidizing bacteria enrichment culture method and the corresponding denitrification process, includes the following steps: Step (1) Preparation of functional carriers; Step (2) Functional carrier preprocessing to obtain preprocessed functional carrier; Step (3) Prepare an anaerobic bacteria enrichment vector to obtain an anaerobic bacteria enrichment vector; Step (4) Pre-treat the high ammonia nitrogen wastewater; Step (5) involves a denitrification reaction; Step (6) Regenerate the anaerobic bacteria enrichment carrier.

[0010] The preparation process of the functional carrier described in this scheme is as follows: First, chitosan powder with a degree of deacetylation ≥90% and a molecular weight of 150-300 kDa and sodium alginate powder with a molecular weight of 100-250 kDa and an M / G ratio of 0.4-0.8 are mixed at a dry weight ratio of 3-5:1. Then, the mixture is dissolved in deionized water to prepare a homogeneous colloidal solution with a total mass concentration of 2-4%. In this colloidal solution, sodium ion-modified clinoptilolite powder with a particle size of 300-400 mesh (passing rate ≥95%) is uniformly dispersed. This zeolite is prepared by ion exchange with 5% NaCl solution at 60℃ for 24 hours, with a Na⁺ exchange rate ≥85%, and its proportion in the final dry weight of the functional carrier is 5-10%. Subsequently, directional freezing technology was used to solidify the mixed colloid: the colloid was placed in a mold with a unidirectional heat-conducting base, and a programmed cold source was used to linearly cool it from the bottom to the core temperature of -20 to -40°C at a rate of 0.5-2.0°C / min, and the temperature was maintained at this level for 2-4 hours. This process induced the directional growth of ice crystals, forming a through-template. Next, the frozen block was immediately transferred to a freeze dryer and sublimated for 24-48 hours under conditions of vacuum degree <10Pa and plate temperature increased from -40℃ to 25℃ to obtain a porous framework with oriented macropore and micropore network. Finally, the dried skeleton was immersed in a crosslinking solution containing 0.5-1.5% glutaraldehyde (v / v) and 1-3% calcium chloride (w / w) and crosslinked at room temperature for 4-8 hours. After the reaction was completed, it was washed with deionized water until the pH of the wash solution was neutral and then dried to obtain the pretreated functional carrier.

[0011] The overall porosity of the final pre-treated functional carrier is controlled at 85-95%. Its interior contains macroscopic channels with an average pore size of 50-110 μm formed by directional freezing, and micropores with a pore size of 1-10 μm formed on the pore walls due to the salting-out effect. Together, they form a hierarchical pore structure that is conducive to the deep transport of nutrients and the rapid excretion of metabolic products.

[0012] To endow functional carriers with the ability to actively respond to the physiological needs of microorganisms, a systematic functional pretreatment is required, including surface coating construction and gradient loading of active components: First, the prepared and sterilized functional carriers are impregnated with a PDA solution using a self-polymerization method. The components of the PDA coating solution include: 2.0 g / L dopamine hydrochloride, 20.4 mg / L metal catalyst, 0.3 g / L surfactant, and 10 mmol / L Tris-HCl buffer (pH 8.5 ± 0.2). The impregnation is carried out at 25 ± 1 °C for 4-6 h, after which the carrier weight increases by 10-15%. The purpose of the PDA coating is to significantly enhance the hydrophilicity and biocompatibility of the functional carrier, providing high-affinity sites for the initial attachment of anaerobic ammonia-oxidizing bacteria; its rich catechol groups can also serve as a powerful metal ion chelating agent. Then, the PDA-coated functional carrier was immersed in the functionalized composite solution for 12-24 hours; the composition of the composite solution was as follows: trace element composite agent: prepared from FeSO4·7H2O and CoCl2·6H2O, the solution contained Fe 2+ With Co 2+ The mass ratio is 6:1-10:1, and the initial total metal ion concentration is 0.05-0.1 g / L. PDA coating chelates and anchors Fe. 2+ and Co 2+This process forms a trace element library of key enzyme cofactors for long-lasting and sustained release; pH buffer: using bicarbonate buffer (NaHCO3 / CO2 system) with an initial concentration of 0.5-2.0 g / L, it is physically adsorbed and stored in the pore network of the functional carrier, providing pH buffering capacity for the biofilm and resisting acid and alkali shocks from the influent; ammonia adsorption material: zeolite powder pre-placed in the functional carrier framework adsorbs ammonium ions in the solution in this step, reaching adsorption saturation, providing a stable low-concentration ammonia nitrogen source for the initial stage of bacterial colony initiation.

[0013] After the preparation and pretreatment of the functional carriers, the immobilization, enrichment, and acclimatization of anaerobic ammonia oxidizing bacteria were initiated. Activated sludge from a stably operating anaerobic ammonia oxidizing reactor was used as the bacterial source, and anaerobic mixed inoculation was carried out at a ratio of 1 gram of VSS to 5-10 grams of pretreated functional carriers. The inoculated functional carriers were then placed in a dedicated acclimatization reactor pre-filled with a synthetic enrichment medium. The initial nitrogen source of the medium was ammonium chloride and sodium nitrite, with a molar ratio strictly controlled at 1:1.27-1.37, and an initial total nitrogen concentration of 200-300 mg / L. The acclimatization process was conducted under strictly controlled conditions: continuous high-purity nitrogen gas was introduced to maintain dissolved oxygen ≤0.2 mg / L; the temperature was maintained at 30-35℃ using a water bath jacket; and the pH was stabilized at 7.2-7.8 using online pH monitoring and an automatic titration system. A gradient loading acclimatization strategy was adopted, with the total nitrogen removal rate in the effluent consistently reaching ≥85% as the cycle marker. Every 7-10 days, the total nitrogen concentration in the influent was increased by 100-200 mg / L until it reached 1000-1200 mg / L. The entire acclimatization cycle lasted 30-60 days. Completion was indicated by: the formation of a brick-red, dense, and uniformly thick biofilm on the surface of the anaerobic enrichment carrier; the specific anaerobic ammonia oxidation activity of the anaerobic enrichment carrier reaching 1.8-2.2 μmol N2 / (gVSS·h); and the nitrogen removal rate per unit volume of the reactor stabilizing at 1.4-1.8 kgN / (m³). 3 ·d).

[0014] After the functional carrier has completed the enrichment and acclimatization of anaerobic ammonia-oxidizing bacteria, it can be put into actual treatment of high ammonia nitrogen wastewater. Before entering the core anaerobic ammonia oxidation reaction unit, the wastewater needs to undergo system pretreatment to eliminate inhibitory factors. The pretreatment first involves adding sodium hydroxide or sulfuric acid to precisely adjust the pH of the wastewater to the range of 7.0-8.0. Subsequently, forced deoxygenation is carried out for 10-20 minutes using vacuum degassing or nitrogen stripping to reduce the dissolved oxygen concentration to below 0.5 mg / L, avoiding competition from aerobic bacteria and poisoning of anaerobic bacteria. The most critical aspect is the control of free ammonia concentration. This process uses a control system based on online ammonia nitrogen and pH sensors to monitor and calculate the free ammonia concentration in real time. A PID controller dynamically adjusts the dilution water volume and pH value to ensure that the free ammonia concentration in the wastewater entering the reaction unit is always below the safe threshold of 25 mg / L. This pretreatment system effectively eliminates the inhibitory effects of dissolved oxygen and free ammonia on anaerobic ammonia-oxidizing bacteria, creating ideal conditions for subsequent biological treatment.

[0015] The pretreated wastewater enters an upflow anaerobic ammonia oxidation reactor for core nitrogen removal. The reactor is fed with 15-25% by volume of acclimated functional carriers and operates continuously under stringent conditions of dissolved oxygen ≤0.2 mg / L and hydraulic retention time 8-12 h. The system utilizes a dynamic control mechanism for real-time optimization. This model integrates online monitoring data on treatment temperature, pH, oxidation-reduction potential, and effluent ammonia nitrogen and nitrite nitrogen to regulate operating parameters. When the temperature or pH deviates from the set values ​​(33±0.5℃, 7.5±0.1℃, respectively), the system immediately initiates compensation adjustments. The system achieves intelligent linkage with the upstream short-cut nitrification unit. By monitoring the ammonia nitrogen to nitrite nitrogen ratio in real time (optimal 1:1.32), when the deviation exceeds ±0.03, the system automatically adjusts the aeration rate or reflux ratio of the upstream unit to ensure a precisely proportioned electron acceptor for anaerobic ammonia oxidation, achieving deep process coupling and maximizing efficiency.

[0016] To ensure long-term stable operation of the process, the system is equipped with an online regeneration and performance recovery procedure for the functional carrier. This procedure is based on real-time diagnostic triggering and continuously monitors parameters such as bed pressure drop and specific substrate utilization rate. When the pressure drop increases by more than 30% or the substrate utilization rate decreases by more than 15%, the regeneration program is automatically initiated. The regeneration process begins by replacing the reactor liquid with a 0.1-0.5 mol / L bicarbonate buffer solution, followed by mechanical agitation at 100-150 rpm or hydraulic rinsing for 2-4 hours to gently remove the outer aged biofilm. This is then followed by 30 minutes of circulating 0.05 mol / L citric acid solution to dissolve inorganic precipitates in the pores. After rinsing, the reactor is rinsed with buffer solution to restore a neutral environment. Finally, the reactor is soaked in a trace element solution for 2 hours to replenish lost key cofactors such as iron and cobalt. The regenerated functional carrier must meet the following performance standards: biofilm thickness restored to 60-100 μm, nitrogen removal rate decrease not exceeding 8%, and compressive strength maintained at over 85% of its initial value. This intelligent operation and regeneration system provides the process with excellent stability and adaptability, enabling it to maintain high-efficiency nitrogen removal performance over the long term.

[0017] In a preferred embodiment of the present invention, the dry weight ratio of chitosan to sodium alginate is precisely set to 4:1 during the preparation of the functional carrier. This ratio ensures sufficient mechanical strength of the functional carrier while providing optimal hydrophilicity and biocompatibility. Furthermore, in this preferred embodiment, the overall porosity of the functional carrier is precisely controlled at 90%, and the average pore size of the macroscopic channels is 80 μm. This combination of structural parameters has been proven to achieve the best balance between mass transfer efficiency and biomass retention capacity. In addition, the zeolite powder is preferably powder that passes through a 400-mesh sieve; a finer particle size provides a larger specific surface area, thereby enhancing its adsorption and sustained release capacity for ammonia nitrogen.

[0018] In a preferred embodiment of the present invention, in the functionalization pretreatment step of the functional carrier, the Fe in the trace element composite agent... 2+ With Co 2+ The mass ratio is precisely set at 8:1. This ratio closely matches the actual stoichiometric requirements of key enzyme systems (such as hydroxylamine oxidase and hydrazine synthase) in anaerobic ammonia-oxidizing bacteria for these two metal ions, thereby maximizing the catalytic activity of the bacterial community.

[0019] In the pretreatment stage of high ammonia nitrogen wastewater, the free ammonia concentration is controlled through a closed-loop feedback control system. This system includes a flow tank equipped with an ammonia nitrogen ion selective electrode and a pH electrode, a PLC controller, and a precision metering pump connected to a dilution water tank and a pH adjuster storage tank. The system continuously adjusts the injection flow rate of the dilution water and the dosing rate of the pH adjuster to control the fluctuation range of the ammonia concentration within a set value (e.g., 20 ± 5 mg / L).

[0020] In a preferred embodiment of the present invention, the hierarchical pore structure of the functional carrier in the denitrification reaction stage significantly improves the mass transfer efficiency within the biofilm. This improvement is attributed to the synergistic effect of the hierarchical pore structure: macropores (50-110 μm): reduce macroscopic mass transfer resistance and promote rapid penetration of nitrite into the carrier interior; micropores (1-10 μm): increase specific surface area, shorten the diffusion path within the biofilm, and optimize the reaction interface. This mass transfer enhancement effect is the key physical basis for achieving high volumetric nitrogen removal rates.

[0021] The above-mentioned process can be ensured long-term stability through the following innovative testing and regeneration methods: (1) The thickness of the biofilm was monitored online by laser confocal microscopy, and the specific activity was dynamically determined by gas chromatography to achieve accurate evaluation of the carrier performance; (2) Establish a dual-parameter regeneration triggering mechanism based on nitrogen removal rate (NRR) and bed pressure difference, and achieve a performance recovery rate of ≥95% after regeneration of functional carrier through ultrasonic-chemical synergistic cleaning process.

[0022] Compared to existing technologies, the advantages of this solution are: This invention establishes a novel high-ammonia nitrogen wastewater treatment process through innovative carrier structure and functional design. A chitosan-sodium alginate composite matrix, combined with sodium ion-modified clinoptilolite powder, is used to construct a hierarchical porous carrier with macropores of 50-110 μm and micropores of 1-10 μm, enhancing nitrite diffusion capacity. The carrier surface is modified using a PDA coating system, improving its hydrophilicity and biocompatibility. Combined with a trace element slow-release system, the specific anaerobic ammonia oxidation activity is significantly increased. Under precisely controlled conditions of 33±0.5℃ and pH 7.5±0.1, the system achieves a total nitrogen removal rate of 96.8%, exhibiting improved resistance to free ammonia shocks compared to traditional processes. The carrier maintains good performance after regeneration, while simultaneously reducing operating costs. Through component optimization and structural innovation, while maintaining high-efficiency nitrogen removal performance, this invention solves technical bottlenecks such as insufficient mechanical strength of traditional carriers, easy biofilm detachment, and unstable trace element supply, providing a highly efficient and economical solution for high-concentration ammonia nitrogen wastewater treatment. Attached Figure Description

[0023] Figure 1 The morphology of the functional powder prepared in Example 1 under a stereomicroscope at 100x magnification; Figure 2 The macroscopic morphology of the functional powder prepared in Example 1 is shown. Detailed Implementation

[0024] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0025] General Implementation Examples The process for enriching and cultivating anaerobic ammonia-oxidizing bacteria and removing nitrogen from high-ammonia-nitrogen wastewater includes the following steps: Step (1) Prepare the functional carrier: Mix chitosan powder with a degree of deacetylation ≥90% and a molecular weight of 150-300kDa and sodium alginate powder with a molecular weight of 100-250kDa and an M / G ratio of 0.4-0.8 at a dry weight ratio of 3-5:1. Then dissolve the mixture in deionized water to prepare a homogeneous colloidal solution with a total mass concentration of 2-4%. In this colloidal solution, uniformly disperse sodium ion modified clinoptilolite powder with a particle size of 300-400 mesh (pass rate ≥95%) to prepare a colloidal functional carrier, which accounts for 5-10% of the final dry weight of the functional carrier. Step (2) Functional carrier pretreatment includes sterilization with 60Co-γ rays followed by PDA solution impregnation and self-polymerization. The PDA coating solution consists of 2.0 g / L dopamine hydrochloride, 20.4 mg / L metal catalyst, 0.3 g / L surfactant, and 10 mmol / L Tris-HCl buffer (pH 8.5 ± 0.2). The carrier is impregnated at 25 ± 1 °C for 4-6 h, resulting in a 10-15% increase in carrier weight. The PDA-coated functional carrier is then immersed in a solution containing trace element composite, pH buffer, and ammonia adsorption material for 12-24 h. The initial loading of the trace element composite is 0.05-0.1 g / L, the initial loading of the pH buffer is 0.5-2.0 g / L, and the initial loading of the ammonia adsorption material is 5-10 g / L. The main functional ions of the trace element composite are Fe... 2+ With Co 2+The mixture is composed of two components with a mass ratio of 6:1 to 10:1. Subsequently, a directional freezing technique is used to solidify the mixed colloid: the colloid is placed in a mold with a unidirectional heat-conducting base, and a programmed cold source is used to linearly cool it from the bottom to a core temperature of -20 to -40°C at a rate of 0.5-2.0°C / min, and maintained at this temperature for 2-4 hours. This process induces the directional growth of ice crystals, forming a through-template. Next, the frozen block is immediately transferred to a freeze dryer and sublimated for 24-48 hours under conditions of vacuum <10 Pa and a plate temperature increased from -40°C to 25°C, obtaining a porous framework with a directional macroporous and microporous network. Finally, the dried framework is immersed in a crosslinking solution containing 0.5-1.5% glutaraldehyde (v / v) and 1-3% calcium chloride (w / w), and crosslinked at room temperature for 4-8 hours. After the reaction, it is washed with deionized water until the pH of the washing solution is neutral, and then dried to obtain the pretreated functional carrier. The overall porosity of the final functional carrier is controlled at 85-95%. Its interior contains macroscopic channels with an average pore size of 50-110 μm formed by directional freezing, and micropores with a pore size of 1-10 μm formed on the pore wall due to the salting-out effect, which together constitute a hierarchical pore structure that is conducive to the deep transport of nutrients and the rapid excretion of metabolic products. Step (3) Prepare the anaerobic bacteria enrichment carrier. Mix the initial bacterial solution with the pretreated functional carrier at a mass ratio of 1 g / (5-10) g, and then inoculate it into an enrichment medium containing ammonium chloride and sodium nitrite for acclimatization. The nitrogen source molar ratio in the enrichment medium is 1:1.27-1.37, and the initial total nitrogen concentration is 200-300 mg / L. During the acclimatization process, the concentration is increased by 100-200 mg / L every 7-10 days, and the final concentration is controlled at 1000-1200 mg / L. The acclimation conditions were: dissolved oxygen ≤0.2 mg / L, temperature 30-35℃, pH 7.2-7.8, and acclimation time 30-60 days. After the acclimation of anaerobic ammonia oxidizing bacteria, an anaerobic bacterial enrichment carrier was obtained, and a biofilm was formed on its surface. The anaerobic ammonia oxidizing activity was 1.8 μmol N2 per gram of volatile suspended solids per hour to 2.2 μmol N2 per gram of volatile suspended solids per hour, and the nitrogen removal rate was 1.4-1.8 kg N / (m³). 3 ·d), to obtain an anaerobic bacteria enrichment vector; Step (4) involves pretreating the high ammonia nitrogen wastewater, including adjusting the pH of the wastewater to the range of 7.0-8.0, introducing nitrogen gas for 10-20 minutes to reduce the dissolved oxygen concentration to ≤0.5mg / L, and then controlling the free ammonia concentration to the range of ≤25mg / L through a combination of dilution and pH control. During the pretreatment stage of high ammonia nitrogen wastewater, the free ammonia concentration is detected in real time by online monitoring equipment, and the dilution ratio and pH value are dynamically adjusted according to the detection results. Step (5) involves a denitrification reaction. Anaerobic bacteria enrichment carriers are added to the pretreated wastewater at 15-25% of the effective volume of the reaction system. The system is operated under conditions of dissolved oxygen ≤0.2 mg / L and hydraulic retention time of 8-12 h. The reaction system is operated through a dynamic control mechanism, with the temperature controlled at 33±0.5℃ and the pH at 7.5±0.1, until the denitrification efficiency is ≥95%. When the temperature or pH value deviates from the set range, an automatic adjustment device is triggered. When the ratio of ammonia nitrogen to nitrite nitrogen in the influent deviates from 1:1.32±0.03, the pre-short-cut nitrification unit is linked to add sodium nitrite. Step (6) Regenerate the anaerobic bacteria enrichment carrier. After every 60-90 days of operation, place the anaerobic bacteria enrichment carrier in 0.1-0.5 mol / L bicarbonate buffer (NaHCO3 / CO2 system) and shake for 2-4 hours at a shaking frequency of 100-150 rpm. The integrated verification method of the whole system includes a system denitrification efficiency ≥95% and a nitrogen removal rate fluctuation range ≤15% in each cycle.

[0026] Detection and Regeneration Control Methods Specific anaerobic ammonium oxidation activity determination: (1) Place 0.5g of the biofilm-loaded carrier into a 150mL anaerobic flask and inject 100mL of NH4+. + Anaerobic buffer solution of bicarbonate (pH 7.5) containing -N and NO2-N (molar ratio 1:1.32, total nitrogen 200 mg / L). (2) The gas was oscillated at 30℃ (120 rpm) and the top gas was extracted every 5 min. The N2 concentration was determined by gas chromatography (GC-2014, TCD detector). (3) Calculate the activity value according to the formula: Activity (μmolN2 / gVSS / h) = ΔCN2×V / (t×mVSS), where ΔCN2 is the change in N2 concentration (μmol / L), V is the liquid volume (L), t is the reaction time (h), and mVSS is the mass of volatile suspended solids (g).

[0027] Regeneration cycle control: I. Regeneration triggering conditions (must be met simultaneously): NRR ≤ 90% of initial value for 3 consecutive days; Bed pressure difference ≥ 25 kPa (25% increase from initial value); II. Regeneration Procedure: Transfer the carrier to the regeneration tank and shake at 120 rpm for 3 hours with 0.3 mol / L bicarbonate buffer (NaHCO3 / CO2 system) (pH 7.5), simultaneously applying 40 kHz sonication for 10 minutes; circulate and rinse with a mixture of 0.05 mol / L citric acid and 0.1 mol / L EDTA for 30 minutes; then re-immerse in a solution containing Fe. 2+ / Co 2+2h in a trace element solution (0.1g / L) at a ratio of (8:1).

[0028] The periodic adjustment rules are shown in Table 1: Table 1. Periodic Adjustment Rules Influent TN concentration (mg / L) Regeneration cycle (days) Allowable NRR decay rate ≤800 75±5 ≤10% >800 50±5 ≤15% Example 1

[0029] The process for enriching and cultivating anaerobic ammonia-oxidizing bacteria and removing nitrogen from high-ammonia-nitrogen wastewater includes the following steps: Step (1) Prepare the functional carrier: Mix chitosan powder with a degree of deacetylation ≥90% and a molecular weight of 150-300kDa and sodium alginate powder with a molecular weight of 100-250kDa and an M / G ratio of 0.4-0.8 at a dry weight ratio of 3-5:1. Then dissolve the mixture in deionized water to prepare a homogeneous colloidal solution with a total mass concentration of 2-4%. In this colloidal solution, uniformly disperse sodium ion modified clinoptilolite powder with a particle size of 300-400 mesh (pass rate ≥95%) to prepare a colloidal functional carrier, which accounts for 5-10% of the final dry weight of the functional carrier. Step (2) Functional carrier pretreatment includes sterilization with 60Co-γ rays followed by PDA solution impregnation and self-polymerization. The PDA coating solution consists of 2.0 g / L dopamine hydrochloride, 20.4 mg / L metal catalyst, 0.3 g / L surfactant, and 10 mmol / L Tris-HCl buffer (pH 8.5 ± 0.2). The carrier is impregnated at 25 ± 1 °C for 4-6 h, resulting in a 10-15% increase in carrier weight. The PDA-coated functional carrier is then immersed in a solution containing trace element composite, pH buffer, and ammonia adsorption material for 12-24 h. The initial loading of the trace element composite is 0.05-0.1 g / L, the initial loading of the pH buffer is 0.5-2.0 g / L, and the initial loading of the ammonia adsorption material is 5-10 g / L. The main functional ions of the trace element composite are Fe... 2+ With Co 2+The mixture is composed of two components with a mass ratio of 6:1 to 10:1. Subsequently, a directional freezing technique is used to solidify the mixed colloid: the colloid is placed in a mold with a unidirectional heat-conducting base, and a programmed cold source is used to linearly cool it from the bottom to a core temperature of -20 to -40°C at a rate of 0.5-2.0°C / min, and maintained at this temperature for 2-4 hours. This process induces the directional growth of ice crystals, forming a through-template. Next, the frozen block is immediately transferred to a freeze dryer and sublimated for 24-48 hours under conditions of vacuum <10 Pa and a plate temperature increased from -40°C to 25°C, obtaining a porous framework with a directional macroporous and microporous network. Finally, the dried framework is immersed in a crosslinking solution containing 0.5-1.5% glutaraldehyde (v / v) and 1-3% calcium chloride (w / w), and crosslinked at room temperature for 4-8 hours. After the reaction, it is washed with deionized water until the pH of the washing solution is neutral, and then dried to obtain the pretreated functional carrier. The overall porosity of the final functional carrier is controlled at 85-95%. Its interior contains macroscopic channels with an average pore size of 50-110 μm formed by directional freezing, and micropores with a pore size of 1-10 μm formed on the pore wall due to the salting-out effect, which together constitute a hierarchical pore structure that is conducive to the deep transport of nutrients and the rapid excretion of metabolic products. Step (3) Prepare the anaerobic bacteria enrichment carrier. Mix the initial bacterial solution with the pretreated functional carrier at a mass ratio of 1 g / (5-10) g, and then inoculate it into an enrichment medium containing ammonium chloride and sodium nitrite for acclimatization. The nitrogen source molar ratio in the enrichment medium is 1:1.27-1.37, and the initial total nitrogen concentration is 200-300 mg / L. During the acclimatization process, the concentration is increased by 100-200 mg / L every 7-10 days, and the final concentration is controlled at 1000-1200 mg / L. The acclimation conditions were: dissolved oxygen ≤0.2 mg / L, temperature 30-35℃, pH 7.2-7.8, and acclimation time 30-60 days. After the acclimation of anaerobic ammonia oxidizing bacteria, an anaerobic bacterial enrichment carrier was obtained, and a biofilm was formed on its surface. The anaerobic ammonia oxidizing activity was 1.8 μmol N2 per gram of volatile suspended solids per hour to 2.2 μmol N2 per gram of volatile suspended solids per hour, and the nitrogen removal rate was 1.4-1.8 kg N / (m³). 3 ·d), to obtain an anaerobic bacteria enrichment vector; Step (4) involves pretreating the high ammonia nitrogen wastewater, including adjusting the pH of the wastewater to the range of 7.0-8.0, introducing nitrogen gas for 10-20 minutes to reduce the dissolved oxygen concentration to ≤0.5mg / L, and then controlling the free ammonia concentration to the range of ≤25mg / L through a combination of dilution and pH control. During the pretreatment stage of high ammonia nitrogen wastewater, the free ammonia concentration is detected in real time by online monitoring equipment, and the dilution ratio and pH value are dynamically adjusted according to the detection results. Step (5) involves a denitrification reaction. Anaerobic bacteria enrichment carriers are added to the pretreated wastewater at 15-25% of the effective volume of the reaction system. The system is operated under conditions of dissolved oxygen ≤0.2 mg / L and hydraulic retention time of 8-12 h. The reaction system is operated through a dynamic control mechanism, with the temperature controlled at 33±0.5℃ and the pH at 7.5±0.1, until the denitrification efficiency is ≥95%. When the temperature or pH value deviates from the set range, an automatic adjustment device is triggered. When the ratio of ammonia nitrogen to nitrite nitrogen in the influent deviates from 1:1.32±0.03, the pre-short-cut nitrification unit is linked to add sodium nitrite. Step (6) Regenerate the anaerobic bacteria enrichment carrier. After every 60-90 days of operation, place the anaerobic bacteria enrichment carrier in 0.1-0.5 mol / L bicarbonate buffer (NaHCO3 / CO2 system) and shake for 2-4 hours at a shaking frequency of 100-150 rpm. The integrated verification method of the whole system includes a system denitrification efficiency ≥95% and a nitrogen removal rate fluctuation range ≤15% in each cycle.

[0030] Detection and Regeneration Control Methods Specific anaerobic ammonium oxidation activity determination: (1) Place 0.5g of the biofilm-loaded carrier into a 150mL anaerobic flask and inject 100mL of NH4+. + Anaerobic buffer solution of bicarbonate (pH 7.5) containing -N and NO2-N (molar ratio 1:1.32, total nitrogen 200 mg / L). (2) The gas was oscillated at 30℃ (120 rpm) and the top gas was extracted every 5 min. The N2 concentration was determined by gas chromatography (GC-2014, TCD detector). (3) Calculate the activity value according to the formula: Activity (μmolN2 / gVSS / h) = ΔCN2×V / (t×mVSS), where ΔCN2 is the change in N2 concentration (μmol / L), V is the liquid volume (L), t is the reaction time (h), and mVSS is the mass of volatile suspended solids (g).

[0031] Regeneration cycle control: I. Regeneration triggering conditions (must be met simultaneously): NRR ≤ 90% of initial value for 3 consecutive days; Bed pressure difference ≥ 25 kPa (25% increase from initial value); II. Regeneration Procedure: Transfer the carrier to the regeneration tank and shake at 120 rpm for 3 hours with 0.3 mol / L bicarbonate buffer (NaHCO3 / CO2 system) (pH 7.5), simultaneously applying 40 kHz sonication for 10 minutes; circulate and rinse with a mixture of 0.05 mol / L citric acid and 0.1 mol / L EDTA for 30 minutes; then re-immerse in a solution containing Fe. 2+ / Co 2+2h in a trace element solution (0.1g / L) at a ratio of (8:1).

[0032] The periodic adjustment rules are shown in Table 1: Table 1. Periodic Adjustment Rules Example 2

[0033] The process for enriching and cultivating anaerobic ammonia-oxidizing bacteria and removing nitrogen from high-ammonia-nitrogen wastewater includes the following steps: Step (1) Preparation of functional carrier: Chitosan powder with a degree of deacetylation ≥90% and a molecular weight of 200kDa and sodium alginate powder with a molecular weight of 150kDa and an M / G ratio of 0.6 are mixed at a dry weight ratio of 4:1. Then, the mixture is dissolved in deionized water to prepare a homogeneous colloidal solution with a total mass concentration of 3%. Sodium ion-modified clinoptilolite powder with a particle size of 350 mesh and a pass rate of ≥95% is uniformly dispersed in this colloidal solution to obtain a colloidal functional carrier, which accounts for 7% of the final dry weight of the functional carrier. Step (2) Functional carrier pretreatment includes sterilization with 60Co-γ rays followed by PDA solution impregnation and self-polymerization. The PDA coating solution consists of 2.0 g / L dopamine hydrochloride, 20.4 mg / L metal catalyst, 0.3 g / L surfactant, and 10 mmol / L Tris-HCl buffer at pH 8.5. The carrier is impregnated at 25°C for 5 h, resulting in a 12% increase in carrier weight. The PDA-coated functional carrier is then immersed in a solution containing a trace element composite agent, pH buffer, and ammonia adsorbent for 18 h. The initial loading of the trace element composite agent is 0.07 g / L, the initial loading of the pH buffer is 1.2 g / L, and the initial loading of the ammonia adsorbent is 7 g / L. The main functional ions of the trace element composite agent are Fe. 2+ With Co 2+The mixture was composed of two components in a mass ratio of 8:1. Subsequently, a directional freezing technique was used to solidify the mixed colloid: the colloid was placed in a mold with a unidirectional heat-conducting base, and the temperature was linearly reduced from the bottom to the core temperature of -30℃ at a rate of 1.0℃ / min under programmed control, and maintained at this temperature for 3 hours. This process induced the directional growth of ice crystals, forming a through-template. Next, the frozen block was immediately transferred to a freeze dryer and sublimated for 36 hours under conditions of vacuum <10Pa and a plate temperature increased from -40℃ to 25℃, obtaining a porous framework with a directional macroporous and microporous network. Finally, the dried framework was immersed in a crosslinking solution containing 1.0% glutaraldehyde (v / v) and 2% calcium chloride (w / w), and crosslinked at room temperature for 6 hours. After the reaction, it was washed with deionized water until the pH of the washing solution was neutral, and then dried to obtain the pretreated functional carrier. The overall porosity of the final functional carrier was controlled at 90%. Its interior contains macroscopic channels with an average pore size of 80 μm formed by directional freezing, and micropores with a pore size of 5 μm formed on the pore wall due to the salting-out effect, which together constitute a hierarchical pore structure that is conducive to the deep transport of nutrients and the rapid excretion of metabolic products. Step (3) Preparation of anaerobic bacteria enrichment carrier: The initial bacterial solution and the pretreated functional carrier were mixed at a mass ratio of 1g:7g and then inoculated into an enrichment medium containing ammonium chloride and sodium nitrite for acclimatization. The nitrogen source molar ratio in the enrichment medium was 1:1.32, the initial total nitrogen concentration was 250mg / L, and the concentration was increased by 150mg / L every 8 days during the acclimatization process, with the final concentration controlled at 1100mg / L. The acclimatization conditions were dissolved oxygen ≤0.2mg / L, temperature 33℃, pH 7.5, and acclimatization time of 45 days. After the anaerobic ammonia oxidizing bacteria enrichment and acclimatization were completed, the anaerobic bacteria enrichment carrier was obtained, and a biofilm was formed on the surface. The anaerobic ammonia oxidizing activity was 2.0μmolN2 per gram of volatile suspended solids per hour, and the nitrogen removal rate was 1.6kgN / (m 3 ·d); Step (4) involves pretreating the high ammonia nitrogen wastewater, including adjusting the pH of the wastewater to 7.5, introducing nitrogen gas for 15 minutes to reduce the dissolved oxygen concentration to ≤0.5mg / L, and then controlling the free ammonia concentration to ≤25mg / L through a combination of dilution and pH control. During the pretreatment stage of the high ammonia nitrogen wastewater, the free ammonia concentration is detected in real time by online monitoring equipment, and the dilution ratio and pH value are dynamically adjusted according to the detection results. Step (5) involves a denitrification reaction. Anaerobic bacteria enrichment carriers are added to the pretreated wastewater at 20% of the effective volume of the reaction system. The system is operated under conditions of dissolved oxygen ≤0.2 mg / L and hydraulic retention time of 10 h. The reaction system is operated through a dynamic control mechanism, with the temperature controlled at 33±0.5℃ and the pH at 7.5±0.1, until the denitrification efficiency is ≥95%. When the temperature or pH value deviates from the set range, an automatic adjustment device is triggered. When the ratio of ammonia nitrogen to nitrite nitrogen in the influent deviates from 1:1.32, sodium nitrite is added to the pre-short-range nitrification unit. Step (6) Regenerate the anaerobic bacteria enrichment carrier. After every 75 days of operation, place the anaerobic bacteria enrichment carrier in 0.3 mol / L bicarbonate anaerobic buffer and shake for 3 hours at a shaking frequency of 120 rpm. The integrated verification method of the whole system includes a system denitrification efficiency ≥95% and a nitrogen removal rate fluctuation range ≤15% in each cycle. Example 3

[0034] The process for enriching and cultivating anaerobic ammonia-oxidizing bacteria and removing nitrogen from high-ammonia-nitrogen wastewater includes the following steps: Step (1) Preparation of functional carrier: Chitosan powder with a degree of deacetylation ≥90% and a molecular weight of 150kDa and sodium alginate powder with a molecular weight of 100kDa and an M / G ratio of 0.4 are mixed at a dry weight ratio of 3:1. Then, the mixture is dissolved in deionized water to prepare a homogeneous colloidal solution with a total mass concentration of 2%. Sodium ion-modified clinoptilolite powder with a particle size of 300 mesh and a pass rate of ≥95% is uniformly dispersed in this colloidal solution to obtain a colloidal functional carrier, which accounts for 5% of the final dry weight of the functional carrier. Step (2) Functional carrier pretreatment includes sterilization with 60Co-γ rays followed by PDA solution impregnation and self-polymerization. The PDA coating solution consists of 2.0 g / L dopamine hydrochloride, 20.4 mg / L metal catalyst, 0.3 g / L surfactant, and 10 mmol / L Tris-HCl buffer at pH 8.5. The carrier is impregnated at 25°C for 4 h, resulting in a 10% increase in carrier weight. The PDA-coated functional carrier is then immersed in a solution containing a trace element composite agent, pH buffer, and ammonia adsorbent for 12 h. The initial loading of the trace element composite agent is 0.05 g / L, the initial loading of the pH buffer is 0.5 g / L, and the initial loading of the ammonia adsorbent is 5 g / L. The main functional ions of the trace element composite agent are Fe. 2+ With Co 2+The mixture was composed of two components in a mass ratio of 6:1. Subsequently, a directional freezing technique was used to solidify the mixed colloid: the colloid was placed in a mold with a unidirectional heat-conducting base, and the temperature was linearly reduced from the bottom to the core temperature of -20℃ at a rate of 0.5℃ / min under programmed control, and maintained at this temperature for 2 hours. This process induced the directional growth of ice crystals, forming a through-template. Next, the frozen block was immediately transferred to a freeze dryer and sublimated for 24 hours under a vacuum of <10Pa and a plate temperature increased from -40℃ to 25℃, yielding a porous framework with a directional macroporous and microporous network. Finally, the dried framework was immersed in a crosslinking solution containing 0.5% glutaraldehyde (v / v) and 1% calcium chloride (w / w), and crosslinked at room temperature for 4 hours. After the reaction, the mixture was washed with deionized water until the pH of the washings was neutral, and then dried to obtain the pretreated functional carrier. The overall porosity of the final functional carrier was controlled at 85%. Its interior contains macroscopic channels with an average pore size of 50 μm formed by directional freezing, and micropores with a pore size of 1 μm formed on the pore wall due to the salting-out effect, which together constitute a hierarchical pore structure that is conducive to the deep transport of nutrients and the rapid excretion of metabolic products. Step (3) Preparation of anaerobic bacteria enrichment carrier: The initial bacterial solution and the pretreated functional carrier were mixed at a mass ratio of 1g:5g and then inoculated into an enrichment medium containing ammonium chloride and sodium nitrite for acclimatization. The nitrogen source molar ratio in the enrichment medium was 1:1.27, the initial total nitrogen concentration was 200mg / L, and the concentration was increased by 100mg / L every 10 days during the acclimatization process, with the final concentration controlled at 1000mg / L. The acclimatization conditions were dissolved oxygen ≤0.2mg / L, temperature 30℃, pH 7.2, and acclimatization time of 60 days. After the anaerobic ammonia oxidizing bacteria enrichment and acclimatization were completed, the anaerobic bacteria enrichment carrier was obtained, and a biofilm was formed on the surface. The anaerobic ammonia oxidizing activity was 1.8μmolN2 per gram of volatile suspended solids per hour, and the nitrogen removal rate was 1.4kgN / (m 3 ·d); Step (4) pretreatment of high ammonia nitrogen wastewater includes adjusting the pH of the wastewater to 7.0, introducing nitrogen gas for 10 minutes to reduce the dissolved oxygen concentration to ≤0.5mg / L, and then controlling the free ammonia concentration to ≤25mg / L through dilution and pH control. During the pretreatment stage of high ammonia nitrogen wastewater, the free ammonia concentration is detected in real time by online monitoring equipment, and the dilution ratio and pH value are dynamically adjusted according to the detection results. Step (5) involves a denitrification reaction. Anaerobic bacteria enrichment carriers are added to the pretreated wastewater at 15% of the effective volume of the reaction system. The system is operated under conditions of dissolved oxygen ≤0.2 mg / L and hydraulic retention time of 12 h. The reaction system is operated through a dynamic control mechanism, with the temperature controlled at 33±0.5℃ and the pH at 7.5±0.1, until the denitrification efficiency is ≥95%. When the temperature or pH value deviates from the set range, an automatic adjustment device is triggered. When the ratio of ammonia nitrogen to nitrite nitrogen in the influent deviates from 1:1.32, the pre-short-range nitrification unit is linked to add sodium nitrite. Step (6) Regenerate the anaerobic bacteria enrichment carrier. After every 90 days of operation, place the anaerobic bacteria enrichment carrier in 0.1 mol / L bicarbonate anaerobic buffer and shake for 4 hours at a shaking frequency of 100 rpm. The integrated verification method of the whole system includes a system denitrification efficiency ≥95% and a nitrogen removal rate fluctuation range ≤15% in each cycle. Example 4

[0035] The process for enriching and cultivating anaerobic ammonia-oxidizing bacteria and removing nitrogen from high-ammonia-nitrogen wastewater includes the following steps: Step (1) Preparation of functional carrier: Chitosan powder with a degree of deacetylation ≥90% and a molecular weight of 300kDa and sodium alginate powder with a molecular weight of 250kDa and an M / G ratio of 0.8 are mixed at a dry weight ratio of 5:1. Then, the mixture is dissolved in deionized water to prepare a homogeneous colloidal solution with a total mass concentration of 4%. Sodium ion-modified clinoptilolite powder with a particle size of 400 mesh and a passing rate of ≥95% is uniformly dispersed in this colloidal solution to obtain a colloidal functional carrier, which accounts for 10% of the final dry weight of the functional carrier. Step (2) Functional carrier pretreatment includes sterilization with 60Co-γ rays followed by PDA solution impregnation and self-polymerization. The PDA coating solution consists of 2.0 g / L dopamine hydrochloride, 20.4 mg / L metal catalyst, 0.3 g / L surfactant, and 10 mmol / L Tris-HCl buffer at pH 8.5. The carrier is impregnated at 26°C for 6 hours, resulting in a 15% increase in carrier weight. The PDA-coated functional carrier is then immersed in a solution containing a trace element composite agent, pH buffer, and ammonia adsorbent for 24 hours. The initial loading of the trace element composite agent is 0.1 g / L, the initial loading of the pH buffer is 2.0 g / L, and the initial loading of the ammonia adsorbent is 10 g / L. The main functional ions of the trace element composite agent are Fe... 2+ With Co 2+The mixture was composed of two components in a mass ratio of 10:1. Subsequently, a directional freezing technique was used to solidify the mixed colloid: the colloid was placed in a mold with a unidirectional heat-conducting base, and the temperature was linearly reduced from the bottom to the core temperature of -40℃ at a rate of 2.0℃ / min under programmed control, and maintained at this temperature for 4 hours. This process induced the directional growth of ice crystals, forming a through-template. Next, the frozen block was immediately transferred to a freeze dryer and sublimated for 48 hours under a vacuum of <10Pa and a plate temperature increased from -40℃ to 25℃, yielding a porous framework with a directional macroporous and microporous network. Finally, the dried framework was immersed in a crosslinking solution containing 1.5% glutaraldehyde (v / v) and 3% calcium chloride (w / w), and crosslinked at room temperature for 8 hours. After the reaction, the mixture was washed with deionized water until the pH of the washings was neutral, and then dried to obtain the pretreated functional carrier. The overall porosity of the final functional carrier was controlled at 95%. Its interior contains macroscopic channels with an average pore size of 110 μm formed by directional freezing, and micropores with a pore size of 10 μm formed on the pore wall due to the salting-out effect, which together constitute a hierarchical pore structure that is conducive to the deep transport of nutrients and the rapid excretion of metabolic products. Step (3) Preparation of anaerobic bacterial enrichment carrier: The initial bacterial solution and the pretreated functional carrier were mixed at a mass ratio of 1g:10g and then inoculated into an enrichment medium containing ammonium chloride and sodium nitrite for acclimatization. The nitrogen source molar ratio in the enrichment medium was 1:1.37, the initial total nitrogen concentration was 300mg / L, and the concentration was increased by 200mg / L every 7 days during the acclimatization process, with the final concentration controlled at 1200mg / L. The acclimatization conditions were dissolved oxygen ≤0.2mg / L, temperature 35℃, pH value 7.8, and acclimatization time of 30 days. After the anaerobic ammonia oxidizing bacteria enrichment and acclimatization were completed, the anaerobic bacterial enrichment carrier was obtained, and a biofilm was formed on the surface. The anaerobic ammonia oxidizing activity was 2.2μmolN2 per gram of volatile suspended solids per hour, and the nitrogen removal rate was 1.8kgN / (m 3 ·d); Step (4) pretreatment of high ammonia nitrogen wastewater includes adjusting the pH of the wastewater to 8.0, introducing nitrogen gas for 20 minutes to reduce the dissolved oxygen concentration to ≤0.5mg / L, and then controlling the free ammonia concentration to ≤25mg / L through dilution and pH control. During the pretreatment stage of high ammonia nitrogen wastewater, the free ammonia concentration is detected in real time by online monitoring equipment, and the dilution ratio and pH value are dynamically adjusted according to the detection results. Step (5) involves a denitrification reaction. Anaerobic bacteria enrichment carriers are added to the pretreated wastewater at 25% of the effective volume of the reaction system. The system is operated under conditions of dissolved oxygen ≤0.2 mg / L and hydraulic retention time of 8 h. The reaction system is operated through a dynamic control mechanism, with the temperature controlled at 33±0.5℃ and the pH at 7.5±0.1, until the denitrification efficiency is ≥95%. When the temperature or pH value deviates from the set range, an automatic adjustment device is triggered. When the ratio of ammonia nitrogen to nitrite nitrogen in the influent deviates from 1:1.32, the pre-short-range nitrification unit is linked to add sodium nitrite. Step (6) Regenerate the anaerobic bacteria enrichment carrier. After every 60 days of operation, place the anaerobic bacteria enrichment carrier in 0.5 mol / L bicarbonate anaerobic buffer and shake for 2 hours at a shaking frequency of 150 rpm. The integrated verification method of the whole system includes a system denitrification efficiency ≥95% and a nitrogen removal rate fluctuation range ≤15% in each cycle. Example 5

[0036] The process for enriching and cultivating anaerobic ammonia-oxidizing bacteria and removing nitrogen from high-ammonia-nitrogen wastewater includes the following steps: Step (1) Preparation of functional carrier: Chitosan powder with a degree of deacetylation ≥90% and a molecular weight of 180kDa and sodium alginate powder with a molecular weight of 120kDa and an M / G ratio of 0.5 are mixed at a dry weight ratio of 3:1. Then, the mixture is dissolved in deionized water to prepare a homogeneous colloidal solution with a total mass concentration of 2.5%. Sodium ion-modified clinoptilolite powder with a particle size of 320 mesh and a passing rate of ≥95% is uniformly dispersed in this colloidal solution to obtain a colloidal functional carrier, which accounts for 6% of the final dry weight of the functional carrier. Step (2) Functional carrier pretreatment includes sterilization with 60Co-γ rays followed by PDA solution impregnation and self-polymerization. The PDA coating solution consists of 2.0 g / L dopamine hydrochloride, 20.4 mg / L metal catalyst, 0.3 g / L surfactant, and 10 mmol / L Tris-HCl buffer at pH 8.3. The carrier is impregnated at 25°C for 4.5 h, resulting in an 11% increase in carrier weight. The PDA-coated functional carrier is then immersed in a solution containing a trace element composite agent, pH buffer, and ammonia adsorbent for 15 h. The initial loading of the trace element composite agent is 0.06 g / L, the initial loading of the pH buffer is 0.8 g / L, and the initial loading of the ammonia adsorbent is 6 g / L. The main functional ions of the trace element composite agent are Fe. 2+ With Co 2+The mixture was composed of two components in a 7:1 mass ratio. Subsequently, a directional freezing technique was used to solidify the colloid: the colloid was placed in a mold with a unidirectional heat-conducting base, and a programmed cold source was used to linearly cool it from the bottom to a core temperature of -25°C at a rate of 0.8°C / min, maintaining this temperature for 2.5 hours. This process induced the directional growth of ice crystals, forming a through-template. Next, the frozen block was immediately transferred to a freeze dryer and sublimated for 30 hours under a vacuum of <10 Pa and a plate temperature increased from -40°C to 25°C, yielding a porous framework with a directional macroporous and microporous network. Finally, the dried framework was immersed in a crosslinking solution containing 0.8% glutaraldehyde (v / v) and 1.5% calcium chloride (w / w), and crosslinked at room temperature for 5 hours. After the reaction, the mixture was washed with deionized water until the pH of the wash solution was neutral, and then dried to obtain the pretreated functional carrier. The overall porosity of the final functional carrier was controlled at 88%. Its interior contains macroscopic channels with an average pore size of 60 μm formed by directional freezing, and micropores with a pore size of 3 μm formed on the pore wall due to the salting-out effect, which together constitute a hierarchical pore structure that is conducive to the deep transport of nutrients and the rapid excretion of metabolic products. Step (3) Preparation of anaerobic bacterial enrichment carrier: The initial bacterial solution and the pretreated functional carrier were mixed at a mass ratio of 1g:6g and then inoculated into an enrichment medium containing ammonium chloride and sodium nitrite for acclimatization. The nitrogen source molar ratio in the enrichment medium was 1:1.30, the initial total nitrogen concentration was 220mg / L, and the concentration was increased by 120mg / L every 9 days during the acclimatization process, with the final concentration controlled at 1050mg / L. The acclimatization conditions were dissolved oxygen ≤0.2mg / L, temperature 32℃, pH 7.4, and acclimatization time of 50 days. After the anaerobic ammonia oxidizing bacteria enrichment and acclimatization were completed, the anaerobic bacterial enrichment carrier was obtained, and a biofilm was formed on the surface. The anaerobic ammonia oxidizing activity was 1.9μmolN2 per gram of volatile suspended solids per hour, and the nitrogen removal rate was 1.5kgN / (m 3 ·d); Step (4) pretreatment of high ammonia nitrogen wastewater includes adjusting the pH of the wastewater to 7.2, introducing nitrogen gas for 12 minutes to reduce the dissolved oxygen concentration to ≤0.5mg / L, and then controlling the free ammonia concentration to ≤25mg / L through dilution and pH control. During the pretreatment stage of high ammonia nitrogen wastewater, the free ammonia concentration is detected in real time by online monitoring equipment, and the dilution ratio and pH value are dynamically adjusted according to the detection results. Step (5) involves a denitrification reaction. Anaerobic bacteria enrichment carriers are added to the pretreated wastewater at 18% of the effective volume of the reaction system. The system is operated under conditions of dissolved oxygen ≤0.2 mg / L and hydraulic retention time of 11 h. The reaction system is operated through a dynamic control mechanism, with the temperature controlled at 33±0.5℃ and the pH at 7.5±0.1, until the denitrification efficiency is ≥95%. When the temperature or pH value deviates from the set range, an automatic adjustment device is triggered. When the ratio of ammonia nitrogen to nitrite nitrogen in the influent deviates from 1:1.32, sodium nitrite is added to the pre-short-cut nitrification unit. Step (6) Regenerate the anaerobic bacteria enrichment carrier. After every 80 days of operation, place the anaerobic bacteria enrichment carrier in 0.2 mol / L bicarbonate anaerobic buffer and shake for 3.5 h at a shaking frequency of 110 rpm. The integrated verification method of the whole system includes a system denitrification efficiency ≥95% and a nitrogen removal rate fluctuation range ≤15% in each cycle. Example 6

[0037] The process for enriching and cultivating anaerobic ammonia-oxidizing bacteria and removing nitrogen from high-ammonia-nitrogen wastewater includes the following steps: Step (1) Preparation of functional carrier: Chitosan powder with a degree of deacetylation ≥90% and a molecular weight of 250kDa and sodium alginate powder with a molecular weight of 200kDa and an M / G ratio of 0.7 are mixed at a dry weight ratio of 4:1. Then, the mixture is dissolved in deionized water to prepare a homogeneous colloidal solution with a total mass concentration of 3.5%. Sodium ion-modified clinoptilolite powder with a particle size of 380 mesh and a passing rate of ≥95% is uniformly dispersed in this colloidal solution to obtain a colloidal functional carrier, which accounts for 9% of the final dry weight of the functional carrier. Step (2) Functional carrier pretreatment includes sterilization with 60Co-γ rays followed by PDA solution impregnation and self-polymerization. The PDA coating solution consists of 2.0 g / L dopamine hydrochloride, 20.4 mg / L metal catalyst, 0.3 g / L surfactant, and 10 mmol / L Tris-HCl buffer (pH 8.7). The carrier is impregnated at 26°C for 5.5 h, resulting in a 14% increase in carrier weight. The PDA-coated functional carrier is then immersed in a solution containing a trace element composite agent, pH buffer, and ammonia adsorbent for 20 h. The initial loading of the trace element composite agent is 0.09 g / L, the initial loading of the pH buffer is 1.8 g / L, and the initial loading of the ammonia adsorbent is 9 g / L. The main functional ions of the trace element composite agent are Fe. 2+ With Co 2+The mixture was composed of two components in a mass ratio of 9:1. Subsequently, a directional freezing technique was used to solidify the mixed colloid: the colloid was placed in a mold with a unidirectional heat-conducting base, and the temperature was linearly reduced from the bottom to the core temperature of -35℃ at a rate of 1.5℃ / min under programmed control, and maintained at this temperature for 3.5 hours. This process induced the directional growth of ice crystals, forming a through-template. Next, the frozen block was immediately transferred to a freeze dryer and sublimated for 42 hours under conditions of vacuum <10Pa and a plate temperature increased from -40℃ to 25℃, obtaining a porous framework with a directional macroporous and microporous network. Finally, the dried framework was immersed in a crosslinking solution containing 1.2% glutaraldehyde (v / v) and 2.5% calcium chloride (w / w), and crosslinked at room temperature for 7 hours. After the reaction, the mixture was washed with deionized water until the pH of the washings was neutral, and then dried to obtain the pretreated functional carrier. The overall porosity of the final functional carrier was controlled at 93%. Its interior contains macroscopic channels with an average pore size of 100 μm formed by directional freezing, and micropores with a pore size of 8 μm formed on the pore wall due to the salting-out effect, which together constitute a hierarchical pore structure that is conducive to the deep transport of nutrients and the rapid excretion of metabolic products. Step (3) Preparation of anaerobic bacteria enrichment carrier: The initial bacterial solution and the pretreated functional carrier were mixed at a mass ratio of 1g:9g and then inoculated into an enrichment medium containing ammonium chloride and sodium nitrite for acclimatization. The nitrogen source molar ratio in the enrichment medium was 1:1.35, the initial total nitrogen concentration was 280mg / L, and the concentration was increased by 180mg / L every 8 days during the acclimatization process, with the final concentration controlled at 1150mg / L. The acclimatization conditions were dissolved oxygen ≤0.2mg / L, temperature 34℃, pH 7.7, and acclimatization time of 40 days. After the anaerobic ammonia oxidizing bacteria enrichment and acclimatization were completed, the anaerobic bacteria enrichment carrier was obtained, and a biofilm was formed on the surface. The anaerobic ammonia oxidizing activity was 2.1μmolN2 per gram of volatile suspended solids per hour, and the nitrogen removal rate was 1.7kgN / (m 3 ·d); Step (4) involves pretreating the high ammonia nitrogen wastewater, including adjusting the pH of the wastewater to 7.8, introducing nitrogen gas for 18 minutes to reduce the dissolved oxygen concentration to ≤0.5mg / L, and then controlling the free ammonia concentration to ≤25mg / L through a combination of dilution and pH control. During the pretreatment stage of the high ammonia nitrogen wastewater, the free ammonia concentration is detected in real time by online monitoring equipment, and the dilution ratio and pH value are dynamically adjusted according to the detection results. Step (5) involves a denitrification reaction. Anaerobic bacteria enrichment carriers are added to the pretreated wastewater at 22% of the effective volume of the reaction system. The system is operated under conditions of dissolved oxygen ≤0.2 mg / L and hydraulic retention time of 9 h. The reaction system is operated through a dynamic control mechanism, with the temperature controlled at 33±0.5℃ and the pH at 7.5±0.1, until the denitrification efficiency is ≥95%. When the temperature or pH value deviates from the set range, an automatic adjustment device is triggered. When the ratio of ammonia nitrogen to nitrite nitrogen in the influent deviates from 1:1.32, sodium nitrite is added to the pre-short-cut nitrification unit. Step (6) Regenerate the anaerobic bacteria enrichment carrier. After every 70 days of operation, place the anaerobic bacteria enrichment carrier in 0.4 mol / L bicarbonate anaerobic buffer and shake for 2.5 h at a shaking frequency of 140 rpm. The integrated verification method of the whole system includes a system denitrification efficiency ≥95% and a nitrogen removal rate fluctuation range ≤15% in each cycle.

[0038] Comparative Example 1 The only difference from Example 1 is that the mass ratio of chitosan powder to sodium alginate is 2:1.

[0039] Comparative Example 2 The only difference from Example 1 is that the proportion of zeolite in the final dry weight of the functional carrier is increased to 15%.

[0040] Comparative Example 3 The only difference from Example 1 is that in step (1) of preparing the functional carrier, chitosan powder and sodium alginate powder are dissolved in deionized water to prepare a homogeneous colloidal solution with a total mass concentration of 5%.

[0041] Comparative Example 4 The only difference from Example 1 is that it was not impregnated with the PDA coating solution.

[0042] Comparative Example 5 The only difference from Example 1 is that the carrier weight increases by 20% after immersion in the PDA coating solution.

[0043] Comparative Example 6 The only difference from Example 1 is that the carrier weight increased by 8% after immersion in the PDA coating solution.

[0044] Comparative Example 7 The only difference from Example 1 is that the functional carrier coated with PDA was not immersed in a solution containing trace element complex, pH buffer and ammonia adsorption material.

[0045] Comparative Example 8 The only difference from Example 1 is that the initial bacterial culture and the pretreated functional carrier are mixed at a mass ratio of 1g / 20g.

[0046] Comparative Example 9 The only difference from Example 1 is that no anaerobic bacteria enrichment carrier was prepared, and the strains and pretreatment functional carriers equivalent to those in Example 1 were separately introduced in step (5).

[0047] Comparative Example 10 The only difference from Example 1 is that the dissolved oxygen in the pretreated wastewater is 0.3 mg / L.

[0048] Table 2 shows the test data for the example.

[0049] Table 2 Detection data from the example index Domestication start time (days) <![CDATA[Stable operation of NRR (kgN / m 3 / d)]]> Stable TN removal rate (%) FA inhibition tolerance (mg / L) NRR stability (fluctuation%) Runtime before first regeneration (days) Performance recovery rate after regeneration (%) Example 1 45 1.6 96.2 28 8 75 92 Example 2 60 1.4 95.1 26 10 90 88 Example 3 30 1.8 97.5 32 6 60 95 Example 4 50 1.5 95.8 27 9 80 90 Example 5 40 1.7 96.9 30 7 70 93 Example 6 45 1.6 96.2 28 8 75 92 Table 3 shows the comparative test data: Table 3 Comparative test data index Domestication start time (days) <![CDATA[Stable operation of NRR (kgN / m 3 / d)]]> Stable TN removal rate (%) FA inhibition tolerance (mg / L) NRR stability (fluctuation%) Runtime before first regeneration (days) Performance recovery rate after regeneration (%) Comparative Example 1 58 1.2 92.3 24 14 65 82 Comparative Example 2 65 1.1 91.5 22 16 50 78 Comparative Example 3 72 0.9 89.7 20 18 45 75 Comparative Example 4 85 0.8 87.2 18 22 35 65 Comparative Example 5 62 1 90.1 21 17 55 76 Comparative Example 6 70 0.95 89 19 19 48 73 Comparative Example 7 90 0.7 85.6 15 25 30 60 Comparative Example 8 100 0.6 83.5 16 28 25 55 Comparative Example 9 110 0.5 80.2 14 30 20 50 Comparative Example 10 55 1 88.8 23 15 58 79

[0050] In this embodiment, the preparation parameters of the functional carrier are optimized, with reasonable ratios of chitosan and sodium alginate, zeolite content, and colloidal concentration. The resulting hierarchical pore structure (oriented macropore and micropore network) facilitates nutrient transport and metabolic product discharge. The PDA coating enhances the biocompatibility of the carrier surface, promotes the attachment and proliferation of anaerobic ammonia-oxidizing bacteria, and the loading of trace element complex, pH buffer, and ammonia adsorption material provides a suitable microenvironment for the bacterial community, improving FA inhibition tolerance. The reasonable gradual increase in nitrogen concentration during acclimation allows the bacterial community to gradually adapt to the high-nitrogen environment, enhancing specific activity and nitrogen removal rate. The regeneration conditions are matched with the carrier characteristics to effectively restore biological activity. The synergistic effect of each link ensures high denitrification efficiency, good stability, and excellent regeneration performance. Comparative Example 1: The chitosan to sodium alginate ratio of 2:1 deviated from the optimal range for forming a stable gel structure, resulting in a decrease in the carrier's mechanical strength and porosity, affecting bacterial adhesion and mass exchange. Comparative Example 2: The zeolite content increased to 15%, and the excessive inorganic components reduced the carrier's flexibility, damaged the pore structure, and hindered nutrient transfer. Comparative Example 3: The colloid concentration reached 5%, which increased viscosity and reduced porosity after freeze-drying, hindering bacterial colonization. Comparative Example 4: Without PDA coating, the carrier surface lacked hydrophilic groups and biocompatible sites, weakening the adhesion ability of anaerobic ammonia-oxidizing bacteria and slowing biofilm formation. Comparative Example 5: The PDA coating increased the carrier weight by 20%, and the excessively thick coating blocked some pores, hindering mass exchange. Comparative Example 6: The PDA coating increased the weight by 8%, and the thin coating could not effectively improve the carrier's surface properties, resulting in insufficient biocompatibility. Comparative Example 7: Without the loading of trace elements and other substances, the carrier could not provide the necessary nutritional support and pH for the bacterial community. The buffering capacity and bacterial activity were limited, and the tolerance to FA inhibition decreased. In Comparative Example 8, the initial bacterial culture to carrier ratio was 1:20, and the insufficient bacterial quantity led to slow biofilm formation, prolonged acclimatization start-up time, and reduced nitrogen removal rate. In Comparative Example 9, no enrichment carrier was prepared and the bacteria were added separately, resulting in weak binding between the bacteria and the carrier, easy biofilm detachment, and poor stability. In Comparative Example 10, the dissolved oxygen in the pretreated wastewater was 0.3 mg / L, which exceeded the tolerance range of anaerobic ammonia oxidizing bacteria, inhibiting the anaerobic metabolic activity of the bacteria and leading to a decrease in denitrification efficiency.

Claims

1. A process for denitrification of high ammonia-nitrogen wastewater by enrichment culture of anaerobic ammonia oxidation bacteria, characterized in that, Includes the following steps: Step (1) Preparation of functional carrier: Chitosan powder and sodium alginate powder are mixed in a dry weight ratio of 3-5:1, then dissolved in water to prepare a homogeneous colloidal solution with a total mass concentration of 2-4%. Sodium ion-modified clinoptilolite powder is added to obtain a colloidal functional carrier; the sodium ion-modified clinoptilolite powder accounts for 5-10% of the functional carrier. Step (2) Functional carrier pretreatment: After sterilization with 60Co-γ rays, the functional carrier is immersed in a PDA coating solution at 25±1℃ for 4-6 hours. After immersion, the carrier weight increases by 10-15%. Then, it is taken out and immersed in a solution containing 0.05-0.1g / L trace element composite agent, 0.5-2.0g / L pH buffer and 5-10g / L ammonia adsorption material for 12-24 hours. Then, it is freeze-dried to obtain a porous framework with oriented macroporous and microporous networks. The dried framework is immersed in a crosslinking solution and crosslinked at room temperature for 4-8 hours. After the reaction, it is washed with deionized water until the pH of the washing solution is neutral. The pretreated functional carrier is then dried. Step (3) Preparation of anaerobic bacteria enrichment carrier: Mix the initial bacterial solution with the pretreated functional carrier at a mass ratio of 1g / (5-10)g, and then inoculate it into the enrichment medium for acclimatization. During the acclimatization process, increase the concentration by 100-200mg / L every 7-10 days, and finally control the concentration at 1000-1200mg / L. The acclimatization conditions are dissolved oxygen ≤0.2mg / L, temperature 30-35℃, pH 7.2-7.8, and acclimatization time is 30-60 days. After the anaerobic ammonia oxidizing bacteria enrichment acclimatization is completed, the anaerobic bacteria enrichment carrier is obtained. Step (4) Pretreatment of high ammonia nitrogen wastewater: Adjust the pH of the wastewater to the range of 7.0-8.0, introduce nitrogen gas for 10-20 minutes to reduce the dissolved oxygen concentration to ≤0.5mg / L, and then control the free ammonia concentration to the range of ≤25mg / L to obtain pretreated wastewater; Step (5) Denitrification reaction: Add 15-25% of the effective volume of the anaerobic bacteria enrichment carrier to the pretreated wastewater. Operate under the conditions of dissolved oxygen ≤0.2mg / L and hydraulic retention time of 8-12h, control the temperature at 33±0.5℃ and pH at 7.5±0.1 until the denitrification efficiency is ≥95%.

2. The process for denitrification of high ammonia-nitrogen wastewater by anaerobic ammonium oxidation (ANAMMOX) bacteria-enriched culture according to claim 1, wherein, The chitosan powder has a mixed deacetylation degree ≥90% and a molecular weight of 150-300kDa; the sodium alginate powder has a molecular weight of 100-250kDa and an M / G ratio of 0.4-0.8; and the sodium ion modified clinoptilolite powder has a particle size of 300-400 mesh.

3. The anaerobic ammonia-oxidizing bacteria enrichment culture and high-ammonia nitrogen wastewater denitrification process as described in claim 1, characterized in that, The PDA coating solution comprises: 2.0 g / L dopamine hydrochloride, 20.4 mg / L metal catalyst, and 0.3 g / L surfactant; the pH of the PDA coating solution is adjusted to 8.5 ± 0.2 using Tris-HCl buffer.

4. The anaerobic ammonia-oxidizing bacteria enrichment culture and high-ammonia nitrogen wastewater denitrification process as described in claim 1, characterized in that, The main functional ion of the trace element complexing agent is Fe in a mass ratio of 6-10: 1 2+ with Co 2+ .

5. The anaerobic ammonia-oxidizing bacteria enrichment culture and high-ammonia nitrogen wastewater denitrification process as described in claim 1, characterized in that, In step (2), the crosslinking solution includes 0.5-1.5% glutaraldehyde by volume and 1-3% calcium chloride by mass.

6. The anaerobic ammonia-oxidizing bacteria enrichment culture and high-ammonia nitrogen wastewater denitrification process as described in claim 1, characterized in that, The overall porosity of the pre-treated functional carrier is controlled at 85-95%.

7. The anaerobic ammonia-oxidizing bacteria enrichment culture and high-ammonia nitrogen wastewater denitrification process as described in claim 1, characterized in that, The nitrogen source in the enrichment medium is ammonium chloride and sodium nitrite in a molar ratio of 1:1.27-1.37, with an initial total nitrogen concentration of 200-300 mg / L.

8. The anaerobic ammonia-oxidizing bacteria enrichment culture and high-ammonia nitrogen wastewater denitrification process as described in claim 1, characterized in that, The anaerobic bacteria-enriched carriers have a specific anammox activity of 1.8 to 2.2 μmol N2 per gram of volatile suspended solids per hour and a nitrogen removal rate of 1.4 to 1.8 kg N / (m3·d). 3 • d).

9. The anaerobic ammonia-oxidizing bacteria enrichment culture and high-ammonia nitrogen wastewater denitrification process as described in claim 1, characterized in that, It also includes step (6) the regeneration process of the anaerobic enrichment carrier: after every 60-90 days of operation, the anaerobic enrichment carrier is placed in 0.1-0.5 mol / L bicarbonate anaerobic buffer solution and shaken for 2-4 hours at a shaking frequency of 100-150 rpm to obtain the recovered and regenerated anaerobic enrichment carrier.

10. The anaerobic ammonia-oxidizing bacteria enrichment culture and high-ammonia nitrogen wastewater denitrification process as described in claim 9, characterized in that, The nitrogen removal rate of the regenerated anaerobic bacteria enrichment carrier fluctuates within 15%.

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