Integrated biotrickling filter ammonia removal method and device

Abstract

This invention discloses an integrated biological trickling filtration ammonia removal method and apparatus, comprising the following steps: S1: Inoculating the biological trickling filter layer with aerobic activated sludge and the ammonia nitrogen conversion layer with anaerobic ammonia oxidation granular sludge, and cultivating them using a circulating biofilm method; S2: Introducing ammonia-containing waste gas, periodically replacing the circulating liquid and adding nutrients; S3: Stopping the replacement of the circulating liquid and instead periodically replenishing with fresh nutrient solution; S4: Reducing the inlet ammonia concentration, completing the acclimatization; S5: Stable operation of synergistic denitrification: closing the leachate discharge hole, allowing the leachate flowing out of the biological trickling filter layer to flow by gravity into the ammonia nitrogen conversion layer, controlling the hydraulic retention time and effluent recirculation ratio of the ammonia nitrogen conversion layer to achieve integrated synergistic denitrification. This application achieves deep denitrification, completely solving secondary pollution. Through the built-in anaerobic ammonia oxidation unit, the total nitrogen removal rate reaches over 90%, avoiding secondary pollution of nitrogen-containing wastewater.

Description

Technical Field

[0001] This invention belongs to the field of environmental biotechnology, and in particular relates to an integrated biological trickling filtration method and apparatus for ammonia removal. Background Technology

[0002] Ammonia emissions from livestock and poultry farms have become a significant issue of non-point source pollution. Ammonia emissions also lead to soil acidification in arable land. Therefore, controlling ammonia pollution from livestock and poultry farming has become an urgent task to ensure food security and public health.

[0003] Biological trickling filtration (BTF) is widely used due to its advantages such as simple operation, low operating costs, and easy control of reaction conditions. Its principle is as follows: ammonia-containing waste gas enters the device and is absorbed by the circulating spray liquid. Nitrifying bacteria (AOB ammonia-oxidizing bacteria and NOB nitrite-oxidizing bacteria) on the surface of the packing material degrade ammonia nitrogen into nitrate nitrogen. However, existing technologies suffer from acidification and deactivation problems. The metabolism of AOB and NOB produces a large amount of hydrogen ions, causing the reactor pH to continuously drop below 6.0. This leads to a sharp decline in the activity of conventional nitrifying bacteria, accumulation of ammonia nitrogen in the spray liquid, re-evaporation of ammonia gas, and system collapse. Existing solutions (external alkali neutralization, frequent liquid changes, and pure bacterial inoculation) all have drawbacks such as high cost, secondary pollution, and poor stability. In addition, existing technologies have the critical problem of failing to remove total nitrogen. Traditional biological trickling filtration can only oxidize ammonia nitrogen into nitrate / nitrite nitrogen, resulting in the continuous accumulation of total nitrogen in the circulating liquid. This necessitates the weekly replacement of large amounts of circulating liquid, wasting water resources and nutrients and causing secondary pollution of nitrogen-containing wastewater. Existing coupled denitrification technologies mostly use external anaerobic ammonia oxidation reactors, which have a large footprint, complex pipelines, low mass transfer efficiency, and cannot be efficiently matched with biotrickling filtration processes.

[0004] Therefore, there is an urgent need to develop an integrated bio-trickling filtration device that combines bio-trickling filtration technology and deep denitrification technology, has a small footprint, and low operating costs. Summary of the Invention

[0005] In view of this, the present invention aims to provide an integrated bio-trickling filtration deammoniation method and apparatus to solve at least one technical problem in the background art.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows: An integrated bio-trickling filtration method for ammonia removal includes the following steps: S1: Aerobic activated sludge is inoculated into the biological trickling filter layer, and anaerobic ammonia oxidation granular sludge is inoculated into the ammonia nitrogen conversion layer. The sludge is then cultivated using a circulating biofilm method. S2: Introduce ammonia-containing waste gas, periodically replace the circulating liquid and add nutrients, and run until NH4 is present in the circulating liquid. + -N and NO3 - The -N ratio reaches the set value; S3: Stop changing the circulating fluid and start periodically adding fresh nutrient solution, running the system until NO2 is added to the circulating fluid. - Both -N concentration and free nitrite concentration reached the set values; S4: Reduce the intake ammonia concentration and run until the ammonia oxidation rate and NH4 are reached. + -N and NO2 - -N, NO2 - -N and NO3 - When -N reaches the set value, taming is complete; S5: Stable operation of synergistic denitrification: Close the leachate discharge hole to allow the leachate flowing out of the biological trickling filter to flow into the ammonia nitrogen conversion layer by gravity, control the hydraulic retention time of the ammonia nitrogen conversion layer and the effluent recirculation ratio to achieve integrated synergistic denitrification.

[0007] Furthermore, in S1, the MLSS of the aerobic activated sludge is 15000–25000 mg / L, the MLSS of the anaerobic ammonia oxidation granular sludge is 12000–22000 mg / L, and the circulating biofilm culture time is 7 days; during the biofilm formation period, the ammonia nitrogen conversion layer is operated with artificial water distribution, and the water composition is 280–320 mg / L of NH4. + -N and NO2 at 280~320 mg / L - -N.

[0008] Further, in step S2, the concentration of the ammonia-containing waste gas introduced is 180~220 ppmv, the gas flow rate is 1.0~2.0 L / min, the circulating liquid is replaced every 7 days, and the operation ends on the 14th day; the NH4 + -N and NO3 - The -N ratio is set to 0.85~0.95:1.

[0009] Furthermore, in step S3, 80-120 mL of fresh nutrient solution is added every 7 days, and the phosphate buffer dosage is 60-80% of the original phosphate buffer dosage, continuing until the 28th day; the NO2... - The set value for -N concentration is 400~500mg / L, the set value for free nitrite concentration is 0.8~1.2mg / L, and the pH of the circulating liquid at the end of operation is 6~7.

[0010] Furthermore, in step S4, the inlet ammonia concentration is reduced to 90-110 ppmv, and the process is continuously acclimatized for 14-17 days; the set value for the ammonia oxidation rate is ≥83%, NH4 + -N and NO2 - The -N ratio is set to 1:1.1~1.5, NO2 - -N and NO3 - The -N ratio is set to 4.5~5:1.

[0011] Furthermore, after the S4 acclimatization is completed, acid-resistant ammonia-oxidizing bacteria, including Ca. Nitrosoglobus, are enriched in the bio-trickling filter layer.

[0012] Furthermore, in S5, the hydraulic retention time of the ammonia nitrogen conversion layer is controlled at 20-24 hours, the effluent reflux ratio is 55-65%, and after continuous operation, the ammonia removal rate reaches over 99.5%, the total nitrogen removal rate reaches over 93.8%, and the pH of the circulating liquid is stabilized at 5.4-5.6. Furthermore, in S2 to S4, the determination of the endpoint of the acclimatization stage and / or the adjustment of the operating status are achieved through an online detection step; the online detection step includes: daily sampling and testing at the reactor's inlet, outlet, and circulating liquid collection area, with the detection indicators including inlet and outlet ammonia concentrations and NH4 in the circulating liquid. + -N, NO2 - -N, NO3 - -N concentration, pH value, temperature, and free nitrite concentration; determine whether the set values ​​described in S2, S3, and S4 have been reached based on the test results.

[0013] Specifically, an integrated bio-trickling filtration deammoniation method includes the following steps: Equipment preparation and inoculation: In the upper biological trickling filter zone of the BTF, fill with 1 cm side length polyurethane sponge or 1 cm diameter wooden balls, with the packing volume accounting for 80%–90% of the effective volume of the biological trickling filter zone; in the bottom anammox unit, fill with 1 cm side length volcanic rock packing, and inoculate with anammox granular sludge, controlling the MLSS at 5000 mg / L; inoculate the biological trickling filter zone with activated sludge taken from the aerobic tank of a municipal wastewater treatment plant, controlling the MLSS at 15000–20000 mg / L, and cultivate using the circulating biofilm method for 7 days; add nutrient-containing circulating liquid to the circulating water tank, controlling the spraying speed at 8–12 mL / min; at this stage, open the original leachate discharge hole, and the anammox unit is in artificial water distribution operation.

[0014] Three-stage gradient acclimation enriches acid-resistant AOB and inhibits NOB: Phase 1 (Co-acclimation of AOB and NOB to produce acid): Ammonia-containing waste gas with a concentration of 0~1000 ppmv is introduced, and the circulating liquid is completely replaced every 7 days; the NH4 content in the circulating liquid is monitored daily. + -N and NO3 - -N concentration, when NH4+ + -N and NO3 - This stage ends when the mass ratio of -N is ≤1:1.

[0015] Phase 2 (FNA Natural Accumulation Inhibits NOB): Stop changing the circulating solution and instead add fresh nutrient solution every 7 days, while reducing the dosage of phosphate buffer (K2HPO4 and KH2PO4) by 70%–90% to allow the pH of the circulating solution to decrease naturally; monitor the NH4+ level in the circulating solution daily. + -N, NO2 - -N, NO3 - -N concentration, pH, and temperature are used to calculate FNA concentration according to formula (1); when pH drops to 6.0 ~ 6.6, NO2 - This phase ends when the -N concentration reaches 400~500 mg / L and the FNA concentration reaches 0.8~1.2 mg / L.

[0016] Phase 3 (Acid-resistant AOB directional enrichment): Reduce the inlet air load by 30%–60%, maintain the circulating liquid pH at 5.3–5.7, and continue acclimatization for 14–21 days; monitor nitrogen concentration daily and calculate nitrite nitrogen accumulation rate (NAR); when NAR ≥ 80%, NH4+ + -N and NO2 - -N mass ratio ≈ 1:1.3 (matching the anaerobic ammonium oxidation stoichiometry), NO2 - -N and NO3 - The domestication is complete when the -N mass ratio is ≥4:1.

[0017] The integrated biological trickling filtration ammonia removal device operates stably: After acclimatization, the original leachate discharge hole is automatically closed, and all leachate flows by gravity into the bottom anaerobic ammonia oxidation unit; the anaerobic ammonia oxidation unit operates in an upflow manner, with the hydraulic retention time controlled at 20~24 h, converting ammonia nitrogen and nitrite nitrogen in the leachate into nitrogen gas; the effluent from the anaerobic ammonia oxidation unit is led out through the drain pipe on the side wall of the reactor, of which 50%~70% is recycled to the circulating water tank, and 30%~50% is discharged in compliance with standards; An integrated bio-trickling filtration ammonia removal device according to the above method includes: The tower body, from top to bottom, is provided with a spray layer, a biological trickling filter layer, an ammonia nitrogen conversion layer and a circulating liquid collection area; The spray layer includes a water distributor and nozzles for spraying circulating liquid downwards; The bio-trickling filter layer is filled with composite packing material loaded with aerobic activated sludge; The ammonia nitrogen conversion layer is filled with packing material loaded with anaerobic ammonia oxidation granular sludge. The circulating liquid collection area is located at the bottom of the tower body; The tower body is provided with a BTF inlet and a BTF outlet. The BTF outlet is located at the top of the tower body, and the BTF inlet is located between the bio-trickling filter layer and the ammonia nitrogen conversion layer or below the ammonia nitrogen conversion layer. The BTF inlet and outlet are connected to a pipeline. Ammonia gas enters the BTF inlet through a pipeline equipped with a rotor flow meter. The BTF outlet is connected to an outlet pipeline equipped with an outlet valve.

[0018] The bottom of the tower body is provided with a first BTF leachate discharge port and a second BTF leachate discharge port on both sides respectively. The first BTF leachate discharge port and the second BTF leachate discharge port are connected to the circulating water tank through pipes. The tower body also includes a circulating pipeline, on which a spray pump and a circulating water tank are provided. An anaerobic ammonia oxidation unit leachate outlet is provided between the biological trickling filter layer and the ammonia nitrogen conversion layer. The anaerobic ammonia oxidation unit leachate outlet is connected to the circulating water tank through a pipe.

[0019] Furthermore, the bottom of the tower is equipped with an artificial water inlet for the anaerobic ammonia oxidation unit, and the artificial water tank for the anaerobic ammonia oxidation unit is connected to the artificial water inlet for the anaerobic ammonia oxidation unit through a pipe; The composite filler in the bio-trickling filter layer is selected from one or more of polyurethane sponge, activated carbon fiber, ceramic particles, and plastic suspension balls; the filler in the ammonia nitrogen conversion layer is selected from one or more of polyurethane sponge, zeolite, volcanic rock, and bio-ceramic particles; and a gas distributor is provided at the air inlet.

[0020] The circulating fluid is replenished with nutrients every 30 days, and 1 / 4 of the circulating fluid is replaced every 90 days.

[0021] This invention constructs an integrated biological trickling filtration ammonia removal device, specifically including a BTF reactor, a circulating water tank, a spray pump, a rotor flow meter, and an upflow anaerobic ammonia oxidation unit. The key feature is that the circulating pump connects the circulating water tank and the BTF reactor, allowing the circulating water to circulate throughout the entire device. Ammonia gas enters the rotor flow meter via a pipeline, and the rotor flow meter controls the gas flow rate. Nutrients required for microbial growth are periodically replenished in the circulating water. The built-in closed upflow anaerobic ammonia oxidation reaction unit is an independent sealed cavity, fixedly installed at the bottom of the inner layer of the BTF reactor, completely separated from the upper biological trickling filtration zone; the anaerobic ammonia oxidation unit operates in an upflow manner and is internally filled with special anaerobic ammonia oxidation packing material (polyurethane sponge); the initial water intake phase of the anaerobic ammonia oxidation unit is artificially prepared (NO2). - -N: NH4 +-N=1~1.32), the effluent is provided with a separate drain pipe, which is led out through the middle and upper part of the reactor side wall. After the BTF acclimation is completed, the original artificial water inlet can be closed, and the original bottom leachate discharge hole of the BTF reactor can be closed. All the leachate generated in the upper biological trickling filtration zone will flow into the bottom of the anaerobic ammonia oxidation unit by gravity, and the effluent can be returned to the circulating water tank.

[0022] Compared with existing technologies, the integrated bio-trickling filtration deammoniation method and apparatus of the present invention has the following advantages: 1. This application achieves deep denitrification and completely solves secondary pollution. Through the built-in anaerobic ammonia oxidation unit, the total nitrogen removal rate reaches more than 90%, avoiding secondary pollution of nitrogen-containing wastewater.

[0023] 2. This application is an integrated design with a small footprint. The anaerobic ammonia oxidation unit is built into the BTF reactor, requiring no additional space. Compared with the external coupling process, the footprint is reduced by more than 60%, and the piping system is simplified by more than 70%.

[0024] 3. This application has strong acid resistance and high ammonia removal efficiency. Through a three-stage gradient acclimation process, it successfully enriches an acid-resistant AOB bacterial community with Ca. Nitrosoglobus as the dominant bacteria. It can operate stably under pH 5.3~5.7 conditions, with an ammonia removal rate of 99.5%~100%.

[0025] 4. The operating cost of this application is extremely low. It does not require external acid-base neutralization or external carbon source for denitrification. The operating cost is reduced by more than 75% compared with the conventional alkali addition method.

[0026] 5. The system of this application has good stability: it can operate continuously for a long time, and the ammonia removal rate fluctuates by less than 2%. Attached Figure Description

[0027] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 Here are schematic diagrams of the bio-trickling filtration devices in Embodiments 1 and 2 of the present invention: Figure 2 The graphs show the daily variation trends of ammonia inlet and outlet concentrations in the bio-trickling filter devices of Examples 1 and 2 of this invention. Figure 3 The graph shows the change in ammonia removal efficiency of the bio-trickling filter in Examples 1 and 2 of this invention. Figure 4 The graphs show the daily variation trends of nitrogen concentration in circulating water in Examples 1 and 2 of this invention. Figure 5 These are daily pH variation trend diagrams of circulating water in Examples 1 and 2 of the present invention; Figure 6 The graphs show the changes in free nitrite concentration in circulating water in Examples 1 and 2 of this invention. Figure 7 The diagram shows the enrichment of functional bacteria in the biofilm of the packing material in Embodiments 1 and 2 of the present invention; Figure 8 This is a graph showing the change in total nitrogen removal efficiency during the synergistic operation period in Examples 1 and 2 of the present invention; Figure 9 The graph shows the change in ammonia removal efficiency during the synergistic operation period in Examples 1 and 2 of this invention.

[0028] Explanation of reference numerals in the attached figures: 1. BTF air inlet; 2. Anaerobic ammonia oxidation unit leachate inlet; 3. Anaerobic ammonia oxidation unit reactor; 4. Composite packing material loaded with aerobic activated sludge; 5. BTF air outlet; 6. Spray pump; 7. Anaerobic ammonia oxidation unit leachate outlet; 8. Packing material loaded with anaerobic ammonia oxidation granular sludge; 9. Circulating water tank; 10. First BTF leachate discharge outlet; 11. Anaerobic ammonia oxidation unit manual water distribution tank; 12. Anaerobic ammonia oxidation unit manual water distribution inlet; 13. Second BTF leachate discharge outlet. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0030] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] Example 1 An integrated bio-trickling filtration ammonia removal device includes a tower body. The tower body contains, from top to bottom, a spray layer, a bio-trickling filtration layer, an ammonia nitrogen conversion layer (i.e., anaerobic ammonia oxidation unit reactor 3), and a circulating liquid collection zone.

[0032] BTF inlet 1 is located on the tower body, specifically between the bio-trickling filter layer and the ammonia nitrogen conversion layer. Ammonia-containing waste gas enters the tower body through BTF inlet 1 and flows from bottom to top. A gas distributor is installed at BTF inlet 1 to evenly distribute the incoming gas.

[0033] BTF inlet 1 and BTF outlet 5. Ammonia gas enters BTF inlet 1 through a pipeline, and a rotor flow meter is installed on the pipeline. BTF outlet 5 is connected to an outlet pipeline, and an outlet valve is installed on the outlet pipeline.

[0034] The anaerobic ammonia oxidation unit leachate inlet 2 is located between the biological trickling filter layer and the ammonia nitrogen conversion layer, and is used to introduce the leachate flowing out of the biological trickling filter layer into the ammonia nitrogen conversion layer (anaerobic ammonia oxidation unit reactor 3).

[0035] The anaerobic ammonia oxidation unit reactor 3 is located in the lower middle part of the tower, specifically in the ammonia nitrogen conversion layer. Its interior is filled with packing material 8 loaded with anaerobic ammonia oxidation granular sludge. The reactor receives leachate from the biotrickling filter layer and achieves deep denitrification through the anaerobic ammonia oxidation reaction.

[0036] Composite packing material 4, loaded with aerobic activated sludge, is filled into the biotrickling filter bed. In this embodiment, 1×1cm polyurethane sponge is used as the composite packing material, with a filling volume of 0.85 L. The MLSS of the aerobic activated sludge is 20000 mg / L. Ammonia-containing waste gas is absorbed by the circulating spray liquid in the biotrickling filter bed and converted into nitrite and nitrate nitrogen by nitrifying bacteria in the aerobic activated sludge on the surface of the packing material.

[0037] BTF outlet 5 is located at the top of the tower. The purified gas, after treatment by the bio-trickling filter, is discharged from the tower through BTF outlet 5. An ammonia concentration detection device can be installed at the outlet to monitor the treatment effect.

[0038] Spray pump 6 is installed on the circulation pipeline, located between the circulating water tank 9 and the spray layer at the top of the tower. Spray pump 6 is used to pump the circulating liquid in the circulating water tank 9 to the spray layer at the top of the tower, and spray it downwards through the water distributor and nozzles to achieve the absorption of ammonia-containing waste gas and the wetting of the bio-trickling filter layer.

[0039] The anaerobic ammonia oxidation unit leachate outlet 7 is located at the lower part or bottom of the ammonia nitrogen conversion layer (anaerobic ammonia oxidation unit reactor 3). The leachate treated by anaerobic ammonia oxidation is discharged through this outlet and returned to the circulating water tank 9 through a pipeline, realizing the reuse of the circulating liquid.

[0040] The packing material 8, loaded with anammox granular sludge, is placed inside the ammonia nitrogen conversion layer (anammox unit reactor 3). In this embodiment, 1×1cm polyurethane sponge is used as the packing material, with a filling volume of 0.4 L. The MLSS of the anammox granular sludge is 18000 mg / L. This packing layer is used to convert nitrite nitrogen and residual ammonia nitrogen generated by the biotrickling filter layer into nitrogen gas, thereby achieving total nitrogen removal.

[0041] The circulating water tank 9 is located outside the tower body and is connected to the first BTF leachate discharge port 10, the second BTF leachate discharge port 13, and the anaerobic ammonia oxidation unit leachate outlet 7 via pipes. The circulating water tank 9 is used to collect and store the circulating liquid. In this embodiment, the total water volume of the circulating water tank is 2 L.

[0042] The first BTF leachate discharge port 10 is located on one side of the bottom of the tower and is connected to the circulating water tank 9 via a pipe. During the biofilm formation and initial acclimatization stage, this discharge port is opened, allowing the leachate from the bio-trickling filter layer to be directly discharged into the circulating water tank 9 without entering the ammonia nitrogen conversion layer (anaerobic ammonia oxidation unit reactor 3). During the stable operation stage of synergistic denitrification, this discharge port is closed.

[0043] The artificial water tank 11 for the anaerobic ammonia oxidation unit is located outside the tower body and is connected to the artificial water inlet 12 of the anaerobic ammonia oxidation unit via a pipe. The tank stores artificially prepared water (NH4 in this embodiment). + -N=300 mg / L, NO2 - -N=300mg / L), used to provide nutrition for the ammonia nitrogen conversion layer during the initial acclimatization stage and for biofilm formation.

[0044] The artificial water inlet 12 of the anaerobic ammonia oxidation unit is located at the bottom of the tower body, below the ammonia nitrogen conversion layer (anaerobic ammonia oxidation unit reactor 3). Through this inlet, artificial water from the artificial water tank 11 of the anaerobic ammonia oxidation unit can be injected into the ammonia nitrogen conversion layer.

[0045] The second BTF leachate discharge port 13 is located on the other side of the bottom of the tower (opposite to the first BTF leachate discharge port 10), and is also connected to the circulating water tank 9 via a pipe. The second BTF leachate discharge port 13 has the same function as the first BTF leachate discharge port 10. It is opened during the biofilm formation and initial acclimatization stage, and closed during the stable operation stage of synergistic denitrification. It can also be used as a backup discharge port or to empty the tower.

[0046] Operation process description: Biofilm formation and acclimatization stage: Open the first BTF leachate discharge port 10 and the second BTF leachate discharge port 13, and close the anaerobic ammonia oxidation unit leachate inlet port 2. The leachate from the bio-trickling filter layer is directly discharged into the circulating water tank 9 and circulated by the spray pump 6. At the same time, the anaerobic ammonia oxidation unit artificial water supply tank 11 supplies artificial water to the anaerobic ammonia oxidation unit reactor 3 through the anaerobic ammonia oxidation unit artificial water supply inlet port 12, operating independently.

[0047] Stable operation phase of synergistic denitrification: Close the first BTF leachate discharge port 10 and the second BTF leachate discharge port 13, and open the anammox unit leachate inlet port 2. The leachate from the biotrickling filter layer flows by gravity into the anammox unit reactor 3 through the anammox unit leachate inlet port 2. After being treated by the packing material 8 loaded with anammox granular sludge, it is returned to the circulating water tank 9 through the anammox unit leachate outlet port 7, and then sent to the top of the tower for spraying by the spray pump 6, forming an integrated synergistic denitrification cycle.

[0048] This embodiment provides a method for purifying ammonia gas using acidic short-path nitrification bio-trickling filtration coupled with a built-in anaerobic ammonia oxidation unit. Figure 1The apparatus shown is as follows: The BTF reactor has a total volume of 1.5L, an inner diameter of 60mm, and a height of 540mm; the upper biotrickling filtration zone is 360mm high, and the bottom anaerobic ammonia oxidation unit is 180mm high; the biotrickling filtration zone is filled with 1×1cm polyurethane sponge with a volume of 0.85L; the anaerobic ammonia oxidation unit is filled with 1×1cm polyurethane sponge with a volume of 0.4L; the total water volume in the circulating water tank is 2L; the spraying speed is controlled at 10mL / min. Acclimation begins after ammonia gas is introduced. During this process, samples are taken daily at the reactor inlet / outlet and the circulating water tank for testing. The tested indicators are the ammonia concentration at the inlet / outlet and the NH4+ concentration in the circulating liquid. + -N, NO2 - -N, NO3 - -N, pH, temperature; the relative abundance data of functional bacteria were obtained by high-throughput sequencing of biological samples collected at different times, and the concentration of free nitrite in the circulating water was calculated according to formula (1).

[0049] Inoculation and biofilm formation: The anaerobic ammonia oxidation unit was inoculated with granular sludge from an anaerobic ammonia oxidation reactor at a wastewater treatment plant, with MLSS = 18000 mg / L; the biological trickling filter was inoculated with sludge from an aerobic tank at a wastewater treatment plant, with MLSS = 20000 mg / L, and biofilm formation was circulated and cultured for 7 days; the original leachate discharge outlet was opened, and the anaerobic ammonia oxidation unit was operated with artificial water distribution (NH4). + -N=300mg / L, NO2 - -N=300mg / L).

[0050] Three-stage acclimatization: Stage 1: Introduce 200 ppmv ammonia-containing waste gas at a flow rate of 1.0 L / min; replace the circulating liquid every 7 days, and add nutrients according to the basic formula; operate until day 14, NH4 + -N:NO3 - -N=0.9:1, Phase 1 ends. Phase 2: Stop changing the circulating fluid, instead add 100mL of fresh nutrient solution every 7 days, and reduce the phosphate buffer dosage by 80%; by day 28, pH=6.5, NO2 - -N=450mg / L, FNA=1.0mg / L, Phase 2 ends. Phase 3: Inlet gas concentration reduced to 100ppmv, pH maintained at around 5.5, continuous acclimatization for 14 days; by day 42, NAR=86%, NH4+ + -N:NO2 - -N=1:1.3, NO2 - -N:NO3 - -N=4.7:1, acclimatization complete. The changes in imported ammonia concentration and load during the three stages are as follows: Figure 2 As shown, the changes in ammonia removal rate in the three-stage unit are as follows: Figure 3 As shown, the nitrogen concentration changes in the circulating water of the three-stage device are as follows: Figure 4As shown. The pH value of the circulating water in the three-stage device changes as follows. Figure 5 As shown, the changes in free nitrite in the circulating water of the three-stage device are as follows: Figure 6 As shown, the enrichment results of acid-resistant AOB after acclimatization are as follows: Figure 7 As shown, novel acid-resistant AOB bacteria Ca. Nitrosoglobus It has become the dominant bacteria.

[0051] Stable operation of synergistic denitrification: The original leachate discharge hole is closed, and all leachate flows into the anaerobic ammonia oxidation unit by gravity; the hydraulic retention time of the anaerobic ammonia oxidation unit is controlled at 20 hours, and the effluent recirculation ratio is 60%; after 200 days of continuous operation, the average ammonia removal rate is 99.8%, the average total nitrogen removal rate is 93.9%, and the pH of the circulating liquid is stable at 5.4-5.6. Figure 8 This is a graph showing the change in total nitrogen removal efficiency during the collaborative operation period. Figure 9 This is a graph showing the change in ammonia removal efficiency during the coordinated operation period.

[0052] Example 2 This embodiment provides a method for purifying ammonia gas using acidic short-path nitrification bio-trickling filtration coupled with a built-in anaerobic ammonia oxidation unit. Figure 1 The apparatus shown is as follows: The BTF reactor has a total volume of 1.5L, an inner diameter of 60mm, and a height of 540mm; the upper biotrickling filtration zone is 360mm high, and the bottom anaerobic ammonia oxidation unit is 180mm high; the biotrickling filtration zone is filled with 1×1cm polyurethane sponge with a volume of 0.85L; the anaerobic ammonia oxidation unit is filled with 1×1cm polyurethane sponge with a volume of 0.4L; the total water volume in the circulating water tank is 1L; the spraying speed is controlled at 10mL / min. Acclimation begins after ammonia gas is introduced. During this process, samples are taken daily at the reactor inlet / outlet and the circulating water tank for testing. The tested indicators are the ammonia concentration at the inlet / outlet and the NH4+ concentration in the circulating liquid. + -N, NO2 - -N, NO3 - -N, pH, temperature; the relative abundance data of functional bacteria were obtained by high-throughput sequencing of biological samples collected at different times, and the concentration of free nitrite in the circulating water was calculated according to formula (1).

[0053] Inoculation and biofilm formation: The anaerobic ammonia oxidation unit was inoculated with granular sludge from an anaerobic ammonia oxidation reactor at a wastewater treatment plant, with MLSS = 18000 mg / L; the biological trickling filter was inoculated with sludge from an aerobic tank at a wastewater treatment plant, with MLSS = 20000 mg / L, and biofilm formation was circulated and cultured for 7 days; the original leachate discharge outlet was opened, and the anaerobic ammonia oxidation unit was operated with artificial water distribution (NH4). + -N=300mg / L, NO2 - -N=300mg / L).

[0054] Three-stage acclimatization: Stage 1: Introduce 200 ppmv ammonia-containing waste gas at a flow rate of 2.0 L / min; replace the circulating liquid every 7 days, and add nutrients according to the basic formula; operate until day 14, NH4 + -N:NO3 - -N=0.9:1, Phase 1 ends. Phase 2: Stop changing the circulating fluid, instead add 100mL of fresh nutrient solution every 7 days, and reduce the phosphate buffer dosage by 80%; by day 28, pH=6.5, NO2 - -N=450mg / L, FNA=1.0mg / L, Phase 2 ends. Phase 3: Inlet gas concentration reduced to 100ppmv, pH maintained at around 5.5, continuous acclimatization for 14 days; by day 45, NAR=83%, NH4+ + -N:NO2 - -N=1:1.3, NO2 - -N:NO3 - -N=4.7:1, acclimatization complete. The changes in imported ammonia concentration and load during the three stages are as follows: Figure 2 As shown, the changes in ammonia removal rate in the three-stage unit are as follows: Figure 3 As shown, the nitrogen concentration changes in the circulating water of the three-stage device are as follows: Figure 4 As shown. The pH value of the circulating water in the three-stage device changes as follows. Figure 5 As shown, the changes in free nitrite in the circulating water of the three-stage device are as follows: Figure 6 As shown, the enrichment results of acid-resistant AOB after acclimatization are as follows: Figure 7 As shown, novel acid-resistant AOB bacteria Ca. Nitrosoglobus (Candidatus Nitrosoglobus) became the dominant bacterium.

[0055] Stable operation of synergistic denitrification: The original leachate discharge hole is closed, and all leachate flows into the anaerobic ammonia oxidation unit by gravity; the hydraulic retention time of the anaerobic ammonia oxidation unit is controlled at 24 hours, and the effluent recirculation ratio is 60%; after 200 days of continuous operation, the average ammonia removal rate is 99.5%, the average total nitrogen removal rate is 93.8%, and the pH of the circulating liquid is stable at 5.4~5.6. Figure 8 This is a graph showing the change in total nitrogen removal efficiency during the collaborative operation period. Figure 9 This is a graph showing the change in ammonia removal efficiency during the coordinated operation period.

[0056] Comparative Example 1 (Conventional acidic short-cut nitrification BTF without coupling anaerobic ammonium oxidation) Using the same apparatus as in Example 1, the bottom anaerobic ammonia oxidation unit was removed, while the original leachate discharge port was retained, and only acidic short-cut nitrification was performed. The average ammonia removal rate was 99.5%; total nitrogen continuously accumulated in the circulating liquid, requiring complete replacement of the circulating liquid every 7 days; the annual water consumption was 25 times that of this invention, and the nitrogen-containing wastewater discharge was 20 times that of this invention.

[0057] Comparative Example 2 (External Anaerobic Ammonium Oxidation Coupled Process) Using the same BTF reactor as in Example 1, an external anaerobic ammonia oxidation reactor of the same volume was connected via pipeline. The average ammonia removal rate was 99.3%, and the average total nitrogen removal rate was 85.7%; the footprint was 1.6 times that of this invention, and the operating cost was 1.4 times that of this invention.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An integrated bio-trickling filtration method for ammonia removal, characterized in that: Includes the following steps: S1: Aerobic activated sludge is inoculated into the biological trickling filter layer, and anaerobic ammonia oxidation granular sludge is inoculated into the ammonia nitrogen conversion layer. The sludge is then cultivated using a circulating biofilm method. S2: Introduce ammonia-containing waste gas, periodically replace the circulating liquid and add nutrients, and run until NH4 is present in the circulating liquid. + -N and NO3 - The -N ratio reaches the set value; S3: Stop changing the circulating fluid and start periodically adding fresh nutrient solution, running the system until NO2 is added to the circulating fluid. - Both -N concentration and free nitrite concentration reached the set values; S4: Reduce the intake ammonia concentration and run until the ammonia oxidation rate and NH4 are reached. + -N and NO2 - -N, NO2 - -N and NO3 - When -N reaches the set value, taming is complete; S5: Stable operation of synergistic denitrification: Close the leachate discharge hole to allow the leachate flowing out of the biological trickling filter to flow into the ammonia nitrogen conversion layer by gravity, control the hydraulic retention time of the ammonia nitrogen conversion layer and the effluent recirculation ratio to achieve integrated synergistic denitrification.

2. The integrated bio-trickling filtration deammoniation method according to claim 1, characterized in that: In S1, the MLSS of aerobic activated sludge is 15,000–25,000 mg / L, and the MLSS of anaerobic ammonia oxidation granular sludge is 12,000–22,000 mg / L. The circulating biofilm culture time is 7 days. During the biofilm formation period, the ammonia nitrogen conversion layer is operated with artificial water distribution, and the water composition is 280–320 mg / L of NH4. + -N and NO2 at 280~320 mg / L - -N.

3. The integrated bio-trickling filtration method for ammonia removal according to claim 1, characterized in that: In step S2, the concentration of ammonia-containing waste gas is 180~220 ppmv, the gas flow rate is 1.0~2.0 L / min, the circulating liquid is replaced every 7 days, and the operation ends on the 14th day; the NH4 + -N and NO3 - The -N ratio is set to 0.85~0.95:

1.

4. The integrated bio-trickling filtration method for ammonia removal according to claim 1, characterized in that: In step S3, 80-120 mL of fresh nutrient solution is added every 7 days, and the phosphate buffer dosage is 60%-80% of the original phosphate buffer dosage. This process continues until day 28. The NO2... - The set value for -N concentration is 400~500mg / L, the set value for free nitrite concentration is 0.8~1.2mg / L, and the pH of the circulating liquid at the end of operation is 6~7.

5. The integrated bio-trickling filtration method for ammonia removal according to claim 1, characterized in that: In step S4, the inlet ammonia concentration is reduced to 90-110 ppmv, and the process is continuously acclimatized for 14-17 days; the set value for the ammonia oxidation rate is ≥83%, NH4 + -N and NO2 - The -N ratio is set to 1:1.1~1.5, NO2 - -N and NO3 - The -N ratio is set to 4.5~5:

1.

6. The integrated bio-trickling filtration method for ammonia removal according to claim 1, characterized in that: After the S4 acclimatization is completed, acid-resistant ammonia-oxidizing bacteria, including Ca. Nitrosoglobus, are enriched in the bio-trickling filter layer.

7. The integrated bio-trickling filtration method for ammonia removal according to claim 1, characterized in that: In S5, the hydraulic retention time of the ammonia nitrogen conversion layer is controlled at 20-24 hours, the effluent reflux ratio is 55%-65%, and after continuous operation, the ammonia removal rate reaches over 99.5%, the total nitrogen removal rate reaches over 93.8%, and the pH of the circulating liquid is stable at 5.4-5.

6.

8. The integrated bio-trickling filtration method for ammonia removal according to claim 1, characterized in that: In steps S2 to S4, the determination of the endpoint of the acclimatization stage and / or the adjustment of the operating status are achieved through online detection steps. These online detection steps include daily sampling and testing at the reactor's inlet, outlet, and circulating liquid collection area. The detection indicators include the inlet and outlet ammonia concentrations and the concentration of NH4+ in the circulating liquid. + -N, NO2 - -N, NO3 - -N concentration, pH value, temperature, and free nitrite concentration; determine whether the set values ​​described in S2, S3, and S4 have been reached based on the test results.

9. An integrated bio-trickling filtration deammoniation device for implementing the method according to any one of claims 1 to 8, characterized in that, include: The tower body, from top to bottom, is provided with a spray layer, a biological trickling filter layer, an ammonia nitrogen conversion layer and a circulating liquid collection area; The spray layer includes a water distributor and nozzles for spraying circulating liquid downwards; The bio-trickling filter layer is filled with composite packing material loaded with aerobic activated sludge; The ammonia nitrogen conversion layer is filled with packing material loaded with anaerobic ammonia oxidation granular sludge. The circulating liquid collection area is located at the bottom of the tower body; The tower body is provided with a BTF inlet and a BTF outlet. The BTF outlet is located at the top of the tower body, and the BTF inlet is located between the bio-trickling filter layer and the ammonia nitrogen conversion layer or below the ammonia nitrogen conversion layer. BTF inlet and BTF outlet. Ammonia gas enters the BTF inlet through a pipeline, which is equipped with a rotor flow meter. The BTF outlet is connected to an outlet pipeline, which is equipped with an outlet valve. The bottom of the tower body is provided with a first BTF leachate discharge port and a second BTF leachate discharge port on both sides respectively. The first BTF leachate discharge port and the second BTF leachate discharge port are connected to the circulating water tank through pipes. The tower body also includes a circulating pipeline, on which a spray pump and a circulating water tank are provided. An anaerobic ammonia oxidation unit leachate outlet is provided between the biological trickling filter layer and the ammonia nitrogen conversion layer. The anaerobic ammonia oxidation unit leachate outlet is connected to the circulating water tank through a pipe.

10. The integrated bio-trickling filtration deammoniation device according to claim 9, characterized in that: The bottom of the tower is equipped with an artificial water inlet for the anaerobic ammonia oxidation unit, and the artificial water tank for the anaerobic ammonia oxidation unit is connected to the artificial water inlet for the anaerobic ammonia oxidation unit through a pipe. The composite filler in the bio-trickling filter layer is selected from one or more of polyurethane sponge, activated carbon fiber, ceramic particles, and plastic suspension balls; the filler in the ammonia nitrogen conversion layer is selected from one or more of polyurethane sponge, zeolite, volcanic rock, and bio-ceramic particles; and a gas distributor is provided at the air inlet.

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