High-ammonia-nitrogen wastewater treatment method

Abstract

The invention discloses a high-ammonia-nitrogen wastewater treatment method, and belongs to the field of water treatment. The method comprises the following steps: firstly, carrying out FeCl2 solution activation on a Fe0 + SiO2 core-shell structure vertical suspension carrier, then adding magnetic nanoparticles in an anaerobic ammonium oxidation zone, applying an external magnetic field, guiding anaerobic ammonium oxidation bacteria to be enriched on the surface of the carrier, domesticating at 15 DEG C, and inducing to form a high-coverage biological membrane. The system adopts a partition coupling design: a partial ammonia nitrogen is converted into nitrite by a short-cut nitrification tank; in the short-cut denitrification zone, organic matters in raw water are utilized to reduce residual nitrate in the system into nitrite; and in the anaerobic ammonia oxidation zone, ammonia nitrogen and the nitrite provided in the previous step are used for denitrification. By intelligently controlling internal reflux, the by-product nitrate of anaerobic ammonia oxidation is converted into nitrite for reuse, and internal circulation of nitrogen is formed. The method solves the problems of slow growth and easy loss of anaerobic ammonium oxidation bacteria, by-product nitrate accumulation, low-temperature activity inhibition and the like, and significantly improves the denitrification efficiency and stability of the system.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, and specifically relates to a method for treating high ammonia nitrogen wastewater. Background Technology

[0002] With the rapid development of my country's industry and increasingly stringent environmental regulations, the efficient treatment of high-ammonia-nitrogen wastewater has become a core issue in the field of industrial wastewater treatment. This type of wastewater widely originates from agricultural discharges, food processing, fertilizer production, petrochemical industries, and other sectors. Its high ammonia-nitrogen concentration and complex composition not only easily lead to eutrophication of water bodies and disruption of ecological balance but also pose potential hazards to human health, thus becoming a research hotspot and technical challenge in the field of environmental protection.

[0003] Among high ammonia nitrogen wastewater treatment technologies, anaerobic ammonia oxidation (Anammox) technology stands out due to its significant advantages. This technology requires no additional carbon source or oxygen and can directly remove ammonia nitrogen (NH4+). + -N) and nitrite nitrogen (NO2) - Anaerobic ammonia oxidation (ANAO) converts nitrogen (N2) into nitrogen gas, significantly reducing energy consumption and carbon emissions during wastewater treatment. Compared to traditional nitrification-denitrification processes, ANAO has higher nitrogen removal efficiency and lower operating costs, and has gradually become the preferred technology for treating high ammonia nitrogen wastewater.

[0004] Traditional anaerobic ammonia oxidation (AAO) processes still face a series of technical bottlenecks in practical applications. Firstly, AAO bacteria themselves are slow-growing and easily lost due to hydraulic erosion. They are also highly sensitive to environmental factors such as dissolved oxygen and temperature, especially at low temperatures (e.g., 15°C), where their metabolic activity significantly decreases, easily leading to system inactivation. Secondly, in terms of process operation, excessive organic matter in the influent can cause heterotrophic bacteria to compete with AAO bacteria for substrates, disrupting the bacterial community structure. Simultaneously, process control is complex, prone to substrate imbalance, and the system has weak resistance to shock loads, recovering slowly after fluctuations in influent water quality. More critically, this process has inherent theoretical limitations; the reaction byproduct nitrate continuously accumulates, making it difficult to exceed the theoretical upper limit of approximately 89% for total nitrogen removal, thus failing to achieve simultaneous and efficient removal of ammonia nitrogen and nitrate from the influent.

[0005] Traditional anaerobic ammonium oxidation (ANAO) processes are sensitive to environmental factors (such as dissolved oxygen (DO) and temperature), and excessive organic matter entering the ANAO zone can lead to competition for substrates between heterotrophic bacteria and anaerobic ammonium oxidizing bacteria (AnAOB). Furthermore, they produce nitrate nitrogen (NO3) as a byproduct. - The accumulation of nitrogen oxides (NOx) limits the denitrification rate to a theoretical upper limit of 89%, making it impossible to simultaneously remove the main pollutant, ammonia nitrogen (NH4). + -N) and byproduct NO3 -The system suffers from the drawbacks of -N and also faces technical challenges such as complex process control leading to substrate imbalance, slow system recovery when influent ammonia nitrogen concentration fluctuates, significantly reduced metabolic activity of AnAOB at low temperatures (15℃) leading to inactivation, slow growth of AnAOB, and low denitrification load due to easy loss of biomass by hydraulic scouring. Summary of the Invention

[0006] The purpose of this invention is to provide a method for treating high ammonia nitrogen wastewater, addressing the problems of high operating costs due to carbon source dependence in traditional anaerobic ammonia oxidation processes, excessive organic matter entering the anaerobic ammonia oxidation zone causing competition for substrates between heterotrophic bacteria and anaerobic ammonia oxidizing bacteria (AnAOB), and the production of nitrate nitrogen (NO3) as a byproduct. - The accumulation of nitrogen oxides (NOx-N) limits the denitrification rate to a theoretical upper limit of 89% and makes it impossible to simultaneously remove the main pollutant, ammonia nitrogen (NH4). + -N) and NO3 - -N, complex process control that easily leads to substrate imbalance, slow system recovery when influent ammonia nitrogen concentration fluctuates, significant reduction in AnAOB metabolic activity at 15℃ and easy inactivation, slow growth of AnAOB and easy loss of biomass due to hydraulic scouring, resulting in low denitrification load.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for treating high ammonia nitrogen wastewater, comprising the following steps:

[0008] (1) Carrier pretreatment: Fe was selected 0 +SiO2 core-shell structured vertical suspension carrier, after ultrasonic cleaning, is immersed in FeCl2 solution to activate the carrier micropores;

[0009] (2) Magnetic induction colonization of bacteria: Anaerobic ammonia oxidizing bacteria sludge is inoculated into the anaerobic ammonia oxidation zone, Fe3O4 magnetic nanoparticles are added and an external magnetic field is applied to guide the anaerobic ammonia oxidizing bacteria to accumulate on the surface of the carrier;

[0010] (3) Low temperature biofilm induction: The temperature of the control system is set at 15℃ for gradient acclimatization, and organic nutrients are added regularly to induce the bacterial community to secrete extracellular polymers to form a biofilm;

[0011] (4) Start-up performance acceptance: Test the biofilm coverage, abundance of anaerobic ammonia oxidizing bacteria and HDH enzyme activity. After meeting the standards, it will enter formal operation;

[0012] (5) Segmented water intake distribution: 50-60% of the raw water is injected into the short-cut nitrification tank through the raw water pump, and the remaining 40-50% of the raw water is directly connected to the short-cut denitrification zone through the bypass.

[0013] (6) Short-cut nitrification: The short-cut nitrification tank operates in a low dissolved oxygen environment. Oxygen is controlled by linking microporous aeration pipes with a dissolved oxygen sensor, and the carbon-to-nitrogen ratio and ammonia-to-nitrogen concentration are controlled simultaneously to reduce N4+. +-N is converted to NO2 - -N;

[0014] (7) Short-cut denitrification: The effluent from the short-cut nitrification tank is mixed with the bypass raw water and the return liquid from the anaerobic ammonia oxidation zone and enters the short-cut denitrification zone to maintain the anaerobic environment. Carbon source is dynamically added based on ORP / pH data to reduce NO3. - -N is reduced to NO2 - -N;

[0015] (8) Anaerobic ammonia oxidation reaction: The effluent from the short-cut denitrification zone enters the anaerobic ammonia oxidation zone to maintain an anaerobic environment. Anaerobic ammonia oxidizing bacteria use NO2 - -N and NH4 + -N is converted to N2 as a substrate, and the reaction byproducts are refluxed to the short-cut denitrification zone;

[0016] (9) Sedimentation and effluent: The effluent from the anaerobic ammonia oxidation zone is separated into solid and liquid by an inclined plate sedimentation device. The supernatant is discharged in compliance with standards, and the settled sludge is returned to each reaction zone as needed.

[0017] (10) Intelligent control: Real-time collection of operating parameters of each reaction zone through online sensors, dynamic adjustment of operating conditions, and response to fluctuations in influent water quality.

[0018] Furthermore, in step (1), the carrier is immersed in the FeCl2 solution for 24 hours.

[0019] Furthermore, in step (2), the inoculated anaerobic ammonia-oxidizing bacteria sludge meets the following requirements: AnAOB abundance > 10%, MLSS ≥ 5 g / L; Fe3O4 magnetic nanoparticle dosage is 50 mg / L, and external magnetic field strength is 0.5 T.

[0020] Furthermore, in step (4), the performance acceptance criteria are: biofilm coverage ≥90%, anaerobic ammonia oxidizing bacteria abundance >20%, and HDH enzyme activity reaching 70% to 80% of room temperature.

[0021] Furthermore, in step (6), the dissolved oxygen in the short-cut nitrification tank is controlled at 0.3-0.5 mg / L, the pH is maintained at 7.5-8.5, and the hydraulic retention time is 4-6 h; the nitrite accumulation rate is >90%, and alkalinity is supplemented when the pH is <7.5.

[0022] Furthermore, in step (7), the DO in the short-cut denitrification zone is ≤0.2 mg / L, ORP is -150±50 mV, pH is 7.0~7.5, and HRT is 2-3 h;

[0023] The reflux ratio of the reflux liquid in the anaerobic ammonia oxidation zone is 200%-300%.

[0024] Furthermore, in step (7), the carbon source is sodium acetate, and other carbon sources are calculated based on the organic matter equivalent with reference to sodium acetate. The amount of carbon source added is determined by the formula:

[0025] The baseline quantity C = 1.72 × C[NO3] - -N]

[0026] The dosage compensation ΔC = 0.5 × (ORP - (-150)) + 0.3 × (pH - 7.2);

[0027] Where 1.72 is the external carbon source coefficient, -150 is the ORP reference set point (mV), and 7.2 is the pH reference set point;

[0028] When ΔC>0, the carbon source dosage = baseline dosage C + dosage compensation ΔC;

[0029] When ΔC < 0, the carbon source dosage = baseline C - compensation dosage |ΔC|.

[0030] Furthermore, in step (10), the parameters collected by the online sensor include DO, ORP, pH, temperature, and NH4. + -N concentration, data collected every 5 minutes; NH4+ in the short-cut nitrification tank. + When the -N concentration suddenly increases, temporarily increase the DO to 0.8 mg / L; when the ORP in the anaerobic ammonia oxidation zone remains above -130 mV, reduce the aeration in the short-cut nitrification tank.

[0031] Furthermore, the water quality fluctuation response in step (10) includes:

[0032] High COD in influent (COD / NH4) + When -N=2), reduce the influent flow to the short-cut denitrification zone, shut off the carbon source addition in this zone, and increase the reflux ratio in the anaerobic ammonia oxidation zone;

[0033] Influent COD too low (COD / NH4) + When -N=0.25), increase the influent flow rate to the short-cut denitrification zone and accurately supplement sodium acetate according to the carbon source addition formula;

[0034] NH4 + When the instantaneous shock of -N reaches 300mg / L, adjust the segmented influent ratio to divert the load and temporarily increase the DO in the short-cut nitrification tank to 0.8mg / L.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] This high-ammonia nitrogen wastewater treatment process utilizes Fe... 0 +SiO2 core-shell support and magnetically induced colonization enhance AnAOB enrichment and retention, using partitioned coupling reaction + low-DO precise oxygen control to inhibit NOB activity and accumulate NO2.- -N, combined with segmented water inflow, organic matter distribution and intelligent parameter control, solves the problems of slow growth, easy loss, sensitivity to DO, substrate competition, and water quality fluctuations affecting denitrification efficiency of AnAOB;

[0037] This high-ammonia nitrogen wastewater treatment process fully utilizes the organic matter in the raw water for short-cut denitrification, requiring little or no external carbon source. Simultaneously, it prevents excessive organic matter from entering the anaerobic ammonia oxidation zone, maintaining the dominant position of anaerobic ammonia oxidizing bacteria.

[0038] This high-ammonia nitrogen wastewater treatment process boasts high nitrogen removal efficiency: through the synergistic coupling and internal circulation of PN-PD-Anammox, it achieves effective removal of the main pollutant NH4. + -N and byproduct NO3 - The dual removal of -N achieves a total nitrogen removal rate of over 95%, exceeding Anammox's theoretical nitrogen removal limit and forming an internal nitrogen cycle.

[0039] This high ammonia nitrogen wastewater treatment process features an intelligent feedback control system that can monitor system operation in real time, effectively solving the problem of substrate imbalance in anaerobic ammonia oxidation reaction. This allows the system to recover stability within 24 hours when the influent ammonia nitrogen concentration fluctuates by ±20%.

[0040] This high ammonia nitrogen wastewater treatment process, Fe 0 +SiO2 slow-release carrier; Fe 2+ As a cofactor of HDH enzyme, it significantly enhances the metabolic activity of AnAOB at 15℃ and prevents low-temperature inactivation.

[0041] This high ammonia nitrogen wastewater treatment process uses a vertical suspended carrier unit to reduce biomass loss, stabilize MLSS at 8.0±0.5g / L, and improve denitrification load. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the system required for the treatment of high ammonia nitrogen wastewater.

[0043] In the diagram: 1. Raw water pump; 2. Short-cut nitrification tank; 3. Microporous aeration pipe; 4. Inlet; 5. Short-cut denitrification zone; 6. Sensing system; 7. Anaerobic ammonia oxidation zone; 8. Vertical suspended carrier; 9. Inclined plate; 10. Separation and sedimentation zone; 11. Outlet; 12. Air outlet; 13. Return pipe; 14. Return pump. Detailed Implementation

[0044] The present invention will be further described below with reference to embodiments.

[0045] The following embodiments are used to illustrate the present invention, but should not be used to limit the scope of protection of the present invention. The conditions in the embodiments can be further adjusted according to specific conditions, and simple improvements to the method of the present invention under the premise of the concept of the present invention are all within the scope of protection claimed by the present invention.

[0046] Please see Figure 1 This invention provides a method for treating high ammonia nitrogen wastewater, comprising the following steps:

[0047] Carrier pretreatment

[0048] Operation: Select Fe 0 +SiO2 core-shell structured vertical suspension carrier 8, ultrasonic cleaning to remove production residues; the carrier is immersed in FeCl2 solution for 24 hours to ensure porosity recovery rate >95%.

[0049] Principle: Ultrasonic cleaning can remove impurities from the carrier surface, avoiding interference with bacterial adhesion; FeCl2 solution activates the carrier micropores, increasing the specific surface area and providing sufficient attachment sites for subsequent colonization of anaerobic ammonia-oxidizing bacteria.

[0050] Magnetic-induced colonization of bacterial strains

[0051] Procedure: Inoculate the anaerobic ammonia oxidation zone with anaerobic ammonia oxidizing bacteria sludge (anaerobic ammonia oxidizing bacteria abundance >10%, MLSS ≥5g / L); add 50mg / L Fe3O4 magnetic nanoparticles, and use a 0.5T external magnetic field to guide the anaerobic ammonia oxidizing bacteria to accumulate on the carrier surface.

[0052] Principle: Fe3O4 magnetic nanoparticles can combine with anaerobic ammonia-oxidizing bacteria, achieving targeted enrichment of the bacterial community under the action of an external magnetic field, rapidly increasing the bacterial concentration in the reaction zone, and avoiding biomass loss caused by initial hydraulic scouring.

[0053] Low-temperature biofilm induction

[0054] Operation: Control the system temperature at 15℃ for gradient acclimatization, add organic nutrients rich in specific amino acids (such as yeast extract) every 3 days, and ensure biofilm coverage >50% on the 30th day.

[0055] Principle: Low-temperature acclimatization can enhance the adaptability of anaerobic ammonia-oxidizing bacteria to low-temperature environments; organic nutrients induce the bacterial community to secrete extracellular polymers (EPS), promote biofilm formation, strengthen the binding stability between bacterial strains and carriers, and pave the way for efficient reactions under low-temperature conditions.

[0056] Startup performance acceptance

[0057] Procedure: Biofilm coverage was ≥90% as determined by SEM electron microscopy, anaerobic ammonia oxidizing bacteria abundance was >20% as determined by qPCR, and HDH enzyme activity was measured to be 70%–80% of that at room temperature. HDH enzyme was placed in anaerobic ammonia oxidation zone 7.

[0058] Principle: Biofilm coverage and anaerobic ammonia oxidizing bacteria abundance are the core indicators for the stable operation of the reaction system. HDH enzyme is a key enzyme in the metabolism of anaerobic ammonia oxidizing bacteria, and its activity directly determines the denitrification efficiency at low temperature. Acceptance indicators ensure that the system reaches the designed processing capacity.

[0059] Segmented water intake distribution (continuous operation)

[0060] Operation: 50-60% of the raw water is injected into the short-cut nitrification tank 2 via raw water pump 1, and the remaining 40-50% is bypassed and directly connected to the short-cut denitrification zone 5; control the COD / NH4 ratio of the influent to the short-cut nitrification tank 2. + -N≤0.5、NH4 + -N≥50mg / L.

[0061] Principle: Segmented influent can divert organic matter in a directional manner, avoiding excessive consumption of carbon source in the short-cut nitrification tank 2 (protecting AOB activity), while providing an endogenous carbon source for the short-cut denitrification zone 5, reducing the need for external carbon source and achieving efficient utilization of carbon source.

[0062] Short-range nitrification (HRT=4-6h)

[0063] Operation: Short-cut nitrification tank 2 is linked to a dissolved oxygen (DO) sensor via microporous aeration pipe 3 with an aperture of 8-10 mm to maintain dissolved oxygen (DO) at 0.3-0.5 mg / L; pH is monitored in real time, and alkalinity is supplemented when pH < 7.5 to ensure nitrite accumulation rate > 90% and NH4+. + -N is converted to NO2 - The conversion rate of -N reaches 50-60%.

[0064] Principle: A low dissolved oxygen (DO) environment can inhibit the activity of nitrite-oxidizing bacteria (NOB) (NOB is more sensitive to dissolved oxygen than ammonia-oxidizing bacteria (AOB)), combined with a low carbon-to-nitrogen ratio (COD / NH4). + The dual inhibition of -N≤0.5 and high ammonia nitrogen concentration (≥50mg / L) ensures that ammonia-oxidizing bacteria (AOB) dominate short-cut nitrification, efficiently generating NO2, the substrate required by anaerobic ammonia oxidizing bacteria. - -N; supplementing alkalinity can neutralize the hydrogen ions produced by nitration and maintain the pH stability of the reaction system.

[0065] Short-range denitrification (HRT=2-3h)

[0066] Operation: The effluent from short-cut nitrification tank 2 is mixed with the bypass raw water and the return liquid from anaerobic ammonia oxidation zone 7 (return ratio 200%-300%) before entering short-cut denitrification zone 5. Dissolved oxygen (DO) is maintained at ≤0.2 mg / L, ORP at -150±50 mV, and pH at 7.0~7.5. ORP / pH data are collected every 5 minutes and analyzed using the formula:

[0067] The baseline quantity C = 1.72 × C[NO3] - -N]

[0068] 1.72 - External carbon source coefficient

[0069] C[NO3 - -N-nitrate nitrogen concentration, mg / L.

[0070] The carbon source compensation amount is calculated as follows: ΔC = 0.5 × (ORP - (-150)) + 0.3 × (pH - 7.2).

[0071] ΔC — Carbon source addition compensation amount, mg / L.

[0072] 0.5—The compensation coefficient for ORP, representing the adjustment intensity of carbon source dosage when ORP deviates from the baseline value.

[0073] ORP—Measured redox potential, mV.

[0074] -150—The baseline set point for ORP, which is the target ORP value for an ideal denitrification environment determined based on extensive engineering experience. When the measured ORP is higher than this value, it indicates that the environmental oxidation is too strong, and the carbon source needs to be increased, mV.

[0075] 0.3 — pH compensation coefficient, the intensity of adjustment of carbon source dosage when pH deviates from the reference value.

[0076] pH — Measured acidity or alkalinity.

[0077] 7.2 — pH reference set point. This is a target value set based on the optimal pH range and alkali production characteristics of denitrifying bacteria. When the measured pH is lower than this value, it indicates that denitrification may be insufficient and a carbon source needs to be added to promote the reaction.

[0078] When ΔC>0, the carbon source dosage = baseline dosage C + dosage compensation ΔC;

[0079] When ΔC < 0, the carbon source dosage = baseline C - compensation dosage |ΔC|.

[0080] When there is no significant deviation (i.e., ΔC≈0), the system maintains a basic dosage to meet the basic short-range denitrification requirements.

[0081] Control strategy: The model uses the sign and magnitude of ΔC to make fine adjustments to the baseline dosage, aiming to achieve dynamic balance.

[0082] Principle: The strictly anaerobic environment of the short-cut denitrification zone 5 provides suitable conditions for short-cut denitrifying bacteria (PDB). PDB utilizes the organic matter in the raw water to convert NO3... - -N is reduced to NO2 - -N enables substrate regeneration; ORP reflects environmental reducibility (ORP is low when carbon source is sufficient), and pH reflects the denitrification process (denitrification consumes hydrogen ions, causing pH to rise). The carbon source addition formula derived from the quantitative relationship between the two can achieve precise carbon source replenishment and avoid waste or deficiency.

[0083] Ultimately, a complete intelligent dosing control model is formed:

[0084] The baseline quantity C = 1.72 × C[NO3] - -N]

[0085] The dosage compensation ΔC = 0.5 × (ORP - (-150)) + 0.3 × (pH - 7.2) (unit: mg / L)

[0086] Anaerobic ammonia oxidation reaction (HRT=8-12h)

[0087] Operation: The effluent from the short-cut denitrification zone 5 enters the anaerobic ammonia oxidation zone 7, maintaining dissolved oxygen (DO) ≤ 0.1 mg / L, ORP = -200 ± 50 mV, and temperature 15-30℃; the reaction byproduct NO3-N is refluxed back to the short-cut denitrification zone 5 through the variable frequency reflux pump 13 to ensure that the mixed liquor suspended solids concentration (MLSS) is stable at 8.0 ± 0.5 g / L.

[0088] Principle: Anaerobic ammonia-oxidizing bacteria, under strictly anaerobic conditions, utilize the NO2 generated in short-cut nitrification tank 2. - -N and residual NH4 in raw water + -N is the substrate, directly converted to N 2： Core reaction: NH4 + +NO2 - →N2↑+2H2O); Fe 0 +SiO2 support for sustained release of Fe 2+ As a cofactor of HDH enzyme, it enhances the low-temperature metabolic activity of anaerobic ammonia oxidizing bacteria; internal reflux realizes NO3-N regeneration, forming a nitrogen internal cycle, breaking through the theoretical denitrification limit of 89% of traditional Anammox; the carrier immobilization effect can avoid the loss of anaerobic ammonia oxidizing bacteria and maintain a high bacterial concentration.

[0089] Sedimentation separation and effluent (continuous operation)

[0090] Operation: The effluent from the anaerobic ammonia oxidation zone flows into the upper sedimentation separation zone, where solid-liquid separation is achieved through an inclined plate 9 sedimentation device. The supernatant is discharged after meeting the standards (COD < 30-50 mg / L, NH4+ < 50 mg / L). + -N<3-8mg / L, TN<10-15mg / L), and the settled sludge is returned to each reaction zone as needed.

[0091] Principle: The inclined plate sedimentation device increases the sedimentation area and shortens the particle settling distance, thereby improving the solid-liquid separation efficiency; sludge recirculation can replenish the bacterial concentration in each reaction zone and maintain the stable operation of the system.

[0092] Conventional parameter adjustment

[0093] Operation: The intelligent control system collects real-time data on dissolved oxygen (DO), ORP, pH, temperature, and NH4 in each reaction zone via online sensors. + -N concentration data, control instructions updated every 5 minutes; NH4 in short-cut nitrification tank 2 + When the -N concentration suddenly increases, temporarily increase the dissolved oxygen (DO) to 0.8 mg / L; when the ORP in the anaerobic ammonia oxidation zone remains above -130 mV, reduce the aeration in the short-cut nitrification tank 2.

[0094] Principle: Real-time parameter monitoring can quickly capture changes in operating conditions, adjust and optimize the nitrification rate by adjusting dissolved oxygen (DO), and maintain the anaerobic environment by regulating ORP, so as to avoid system collapse caused by substrate imbalance or reaction environment destruction.

[0095] Special working conditions response

[0096] Operating Condition 1: Influent COD is too high (COD / NH4) + -N=2)

[0097] Operation: Reduce the influent flow rate of short-cut denitrification zone 5, shut off the carbon source addition in short-cut denitrification zone 5, and increase the reflux ratio in the anaerobic ammonia oxidation zone;

[0098] Principle: High COD leads to the proliferation of heterotrophic bacteria, which compete with anaerobic ammonia oxidizing bacteria for substrate. Diverting the influent can consume excess COD in the short-cut nitrification tank 2, and the dilution of the return liquid can reduce the concentration of organic matter in the anaerobic ammonia oxidation zone.

[0099] Operating Condition 2: Influent COD is too low (COD / NH4) + -N=0.25)

[0100] Operation: Increase the influent flow rate of short-cut denitrification zone 5, and accurately supplement sodium acetate according to the carbon source dosing formula;

[0101] Principle: A sufficient carbon source allows PDB to reduce NO3. - The key to NO3 is optimizing influent distribution to maximize the use of limited endogenous carbon sources and precisely adding exogenous carbon sources to avoid NO3. - -N accumulation.

[0102] Operating Condition 3: NH4 + -N instantaneous shock (up to 300 mg / L)

[0103] Operation: Adjust the segmented influent ratio to divert the load, and temporarily increase the dissolved oxygen in short-cut nitrification tank 2 to 0.8 mg / L;

[0104] Principle: Diversion can reduce the treatment load of short-cut nitrification tank 2, increase dissolved oxygen can accelerate the nitrification rate of AOB, and avoid the inhibition of anaerobic ammonia oxidizing bacteria by high ammonia nitrogen.

[0105] Operation, maintenance and performance monitoring: Weekly testing of biofilm coverage, MLSS concentration and anaerobic ammonia-oxidizing bacteria abundance; monthly calibration of sensor accuracy; replacement of microporous aeration pipe 3 in short-cut nitrification tank 2 every 3 months (as needed); regular cleaning of inclined plate 9 sedimentation device; continuous recording of operating data; optimization of influent distribution ratio and carbon source addition baseline.

[0106] Principle: Regular maintenance can prevent equipment failure and sludge blockage, while continuous monitoring and parameter optimization can ensure that the total nitrogen removal rate of the system remains stable at over 95%.

[0107] Example 1: Influent COD is too high (COD=400mg / L, NH4+) + -N=200mg / L,COD / NH4 + -N=2)

[0108] Risk: Excessive organic matter may enter the short-range denitrification zone 5 and may flow into the anaerobic ammonium oxidation zone 7, leading to the proliferation of heterotrophic bacteria.

[0109] (1) Adjust the influent distribution ratio: reduce the influent volume entering the short-cut denitrification zone 5, and directly introduce most of the high COD wastewater into the short-cut nitrification tank 2 to consume most of the COD.

[0110] (2) Intelligent carbon source addition control: In the short-range denitrification zone 5, the carbon source addition is dynamically turned off or minimized based on the ORP / pH sensor.

[0111] (3) Enhance internal circulation: Increase the internal reflux ratio from anaerobic ammonia oxidation zone 7 to short-cut denitrification zone 5, and dilute the concentration of organic matter entering anaerobic ammonia oxidation zone 7 with low COD mixed liquor.

[0112] Water output performance: COD < 50 mg / L, NH4 + -N<5mg / L, TN<15mg / L.

[0113] Example 2: Influent COD is moderate (COD=100mg / L, NH4+) + -N=200mg / L,COD / NH4 +-N=0.5)

[0114] Water output performance: COD < 30 mg / L, NH4 + -N<3mg / L, TN<10mg / L.

[0115] NH4 in the influent + Under the conditions of -N concentration of 200 mg / L and COD of 100 mg / L, the process was operated continuously for 60 days. The comparison data between the process of this invention and the traditional nitrification-denitrification process are shown in Table 1.

[0116] Table 1 Comparison of the process of this invention with the traditional nitration-denitrification process

[0117] process parameters The process of this invention Traditional nitrification-denitrification process Average total nitrogen removal rate 96.5% 85.2% Cost of carbon source per ton of water 0.20 yuan 0.35 yuan Nitrogen removal efficiency at 15℃ (relative to nitrogen removal efficiency at 25℃) 78% 45% Recovery time against ammonia nitrogen shock load (±20%) <24 hours >72 hours

[0118] Example 3: Influent COD too low (COD=50mg / L, NH4) + -N=200mg / L,COD / NH4 + -N=0.25)

[0119] Risk: Insufficient organic matter in raw water to remove NO3 - -N is completely reduced to NO2. - -N, PD function disabled, NO3 - -N accumulation leads to excessive total nitrogen levels.

[0120] (1) Adjust the influent distribution ratio: increase the influent volume into the short-cut denitrification zone 5 to make the most of the limited original COD.

[0121] (2) Intelligent carbon source addition: The system detects that the ORP of the short-range denitrification zone 5 is continuously high (indicating that denitrification is insufficient), and automatically starts the external carbon source addition system to accurately add carbon source according to the calculation model.

[0122] Water output performance: COD < 30 mg / L, NH4 + -N<5mg / L, TN<12mg / L.

[0123] Example 4: Influent NH4 + -N concentration fluctuates greatly (COD=100mg / L, NH4+) + -N instantaneous impact reaches 300 mg / L)

[0124] Risk: Overloading of short-cut nitrification tank 2 may lead to NO2. - Insufficient or excessive N-N accumulation leads to substrate imbalance and impacts Anammox bacteria.

[0125] (1) Real-time feedback control: via online NH4 +-N sensors monitor the effluent from short-cut nitrification tank 2. If NH4 is detected... + If the -N concentration suddenly increases, the intelligent system can automatically and temporarily increase the dissolved oxygen setpoint of the short-cut nitrification tank 2 (e.g., from 0.5 mg / L to 0.8 mg / L) to accelerate nitrification and avoid substrate inhibition.

[0126] (2) Load distribution: By adjusting the segmented water intake ratio, some high ammonia nitrogen wastewater is temporarily diverted to mitigate the impact.

[0127] Water output performance: COD < 30 mg / L, NH4 + -N<8mg / L, TN<15mg / L.

[0128] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description, and these obvious variations or modifications derived from the spirit of the present invention are still within the protection scope of the present invention.

Claims

1. A method for treating high ammonia nitrogen wastewater, characterized in that... This includes the following steps: (1) Carrier pretreatment: Fe was selected 0 +SiO2 core-shell structured vertical suspension carrier, after ultrasonic cleaning, is immersed in FeCl2 solution to activate the carrier micropores; (2) Magnetic induction colonization of bacteria: Anaerobic ammonia oxidizing bacteria sludge was inoculated into the anaerobic ammonia oxidation zone, Fe3O4 magnetic nanoparticles were added and an external magnetic field was used to guide the anaerobic ammonia oxidizing bacteria to accumulate on the surface of the carrier. (3) Low temperature biofilm induction: The temperature of the control system is set at 15℃ for gradient acclimatization, and organic nutrients are added regularly to induce the bacterial community to secrete extracellular polymers to form a biofilm; (4) Start-up performance acceptance: Test the biofilm coverage, abundance of anaerobic ammonia oxidizing bacteria and HDH enzyme activity. After meeting the standards, it will enter formal operation; (5) Segmented water intake distribution: 50-60% of the raw water is injected into the short-cut nitrification tank through the raw water pump, and the remaining 40-50% of the raw water is directly connected to the short-cut denitrification zone through the bypass. (6) Short-cut nitrification: The short-cut nitrification tank operates in a low dissolved oxygen environment. Oxygen is controlled by linking microporous aeration pipes with a dissolved oxygen sensor, and the carbon-to-nitrogen ratio and ammonia-to-nitrogen concentration are controlled simultaneously to reduce NH4+. + -N is converted to NO2 - -N; (7) Short-cut denitrification: The effluent from the short-cut nitrification tank is mixed with the bypass raw water and the return liquid from the anaerobic ammonia oxidation zone and enters the short-cut denitrification zone to maintain the anaerobic environment. Carbon source is dynamically added based on ORP / pH data to reduce NO3. - -N is reduced to NO2 - -N; (8) Anaerobic ammonia oxidation reaction: The effluent from the short-cut denitrification zone enters the anaerobic ammonia oxidation zone to maintain an anaerobic environment. Anaerobic ammonia oxidizing bacteria use NO2 - -N and NH4 + -N is converted to N2 as a substrate, and the reaction byproducts are refluxed to the short-cut denitrification zone; (9) Sedimentation and effluent: The effluent from the anaerobic ammonia oxidation zone is separated into solid and liquid by an inclined plate sedimentation device. The supernatant is discharged in compliance with standards, and the settled sludge is returned to each reaction zone as needed. (10) Intelligent control: Real-time collection of operating parameters of each reaction zone through online sensors, dynamic adjustment of operating conditions, and response to fluctuations in influent water quality.

2. The method for treating high ammonia nitrogen wastewater according to claim 1, characterized in that: In step (1), the carrier is immersed in FeCl2 solution for 24 hours.

3. The method for treating high ammonia nitrogen wastewater according to claim 1, characterized in that: In step (2), the inoculated anaerobic ammonia-oxidizing bacteria sludge meets the following requirements: AnAOB abundance > 10%, MLSS ≥ 5 g / L; Fe3O4 magnetic nanoparticles are added at a rate of 50 mg / L, and the external magnetic field strength is 0.5 T.

4. The method for treating high ammonia nitrogen wastewater according to claim 1, characterized in that: In step (4), the performance acceptance criteria are: biofilm coverage ≥90%, anaerobic ammonia oxidizing bacteria abundance >20%, and HDH enzyme activity reaching 70% to 80% of room temperature.

5. The method for treating high ammonia nitrogen wastewater according to claim 1, characterized in that: In step (6), the dissolved oxygen in the short-cut nitrification tank is controlled at 0.3-0.5 mg / L, the pH is maintained at 7.5-8.5, and the hydraulic retention time is 4-6 h; the nitrite accumulation rate is >90%, and alkalinity is supplemented when the pH is <7.

5.

6. The method for treating high ammonia nitrogen wastewater according to claim 1, characterized in that: In step (7), the DO in the short-cut denitrification zone is ≤0.2 mg / L, ORP is -150±50 mV, pH is 7.0~7.5, and HRT is 2-3 h; The reflux ratio of the reflux liquid in the anaerobic ammonia oxidation zone is 200%-300%.

7. The method for treating high ammonia nitrogen wastewater according to claim 6, characterized in that: In step (7), the carbon source is sodium acetate. Other carbon sources are calculated based on the organic matter equivalent with reference to sodium acetate. The amount of carbon source added is determined by the formula: The baseline quantity C = 1.72 × C[NO3] - -N] The dosage compensation ΔC = 0.5 × (ORP - (-150)) + 0.3 × (pH - 7.2); Where 1.72 is the external carbon source coefficient, -150 is the ORP reference set point (mV), and 7.2 is the pH reference set point; When ΔC>0, the carbon source dosage = baseline dosage C + dosage compensation ΔC; When ΔC < 0, the carbon source dosage = baseline C - compensation dosage |ΔC|.

8. The method for treating high ammonia nitrogen wastewater according to claim 1, characterized in that: In step (10), the parameters collected by the online sensor include DO, ORP, pH, temperature, and NH4. + -N concentration, data collected every 5 minutes; NH4+ in the short-cut nitrification tank. + When the -N concentration suddenly increases, temporarily increase the DO to 0.8 mg / L; when the ORP in the anaerobic ammonia oxidation zone remains above -130 mV, reduce the aeration in the short-cut nitrification tank.

9. A method for treating high ammonia nitrogen wastewater according to claim 1, characterized in that, The water quality fluctuation response in step (10) includes: High COD in influent (COD / NH4) + When -N=2), reduce the influent flow to the short-cut denitrification zone, turn off the carbon source addition, and increase the reflux ratio of the anaerobic ammonia oxidation zone; Influent COD too low (COD / NH4) + When -N=0.25), increase the influent flow rate to the short-cut denitrification zone and accurately supplement sodium acetate according to the carbon source addition formula; NH4 + When the instantaneous shock of -N reaches 300mg / L, adjust the segmented influent ratio to divert the load and temporarily increase the DO in the short-cut nitrification tank to 0.8mg / L.

Images