Autotrophic nitrogen removal reactor as well as preparation method and application thereof

Abstract

The invention provides an autotrophic nitrogen removal reactor as well as a preparation method and application thereof, and belongs to the technical field of biological sewage treatment. According to the invention, the ammonia nitrogen adsorption material is mounted in the suspension balls to form the porous spherical filler, the adsorption capacity of ammonia nitrogen is improved, a large number of biological membranes are formed on the porous spherical filler through biological domestication, and the biological membranes mainly comprise nitrosobacteria and anaerobic ammonium oxidation bacteria, so that the adsorption capacity of ammonia nitrogen is improved. Due to the fact that nitrosobacteria need to consume a large amount of dissolved oxygen in the ammonia nitrogen conversion process, an anoxic or even anaerobic environment exists on the surface of a biological membrane, basic conditions are provided for growth of anaerobic ammonium oxidation bacteria on the biological membrane, and the anaerobic ammonium oxidation bacteria can secrete a large amount of extracellular polymeric substances in the metabolism denitrification process; and the anaerobic microenvironment is gradually expanded, so that by controlling the concentration of dissolved oxygen in water, the co-growth of the two florae can be simultaneously maintained on a biological membrane on the surface of the zeolite, the conversion and removal of ammonia nitrogen are jointly completed, and a synergistic denitrification effect is formed.

Description

Technical Field

[0001] This invention relates to the field of wastewater biological treatment technology, and in particular to an autotrophic denitrification reactor, its preparation method, and its application. Background Technology

[0002] Direct discharge of industrial and agricultural wastewater containing high concentrations of ammonia nitrogen into water bodies is a major cause of eutrophication and ecological imbalance. Therefore, denitrification treatment is necessary before wastewater discharge. Currently, biological methods for removing ammonia nitrogen from wastewater are the most widely used treatment methods, especially novel biological denitrification technologies based on anammox, which have significant advantages in low-carbon and energy-saving aspects, and their engineering application scale and scope are expanding year by year. Denitrification technologies based on Anammox mainly include: PN-A (-Anammox): This method refers to ammonia-oxidizing bacteria (AOB) first oxidizing ammonia nitrogen (NH4+) under an aerobic environment. + Partial oxidation of nitrogen (-N) into nitrite (NO2) - -N), and then anaerobic ammonia oxidizing bacteria (AnAOB) in an anaerobic environment use NH4+. + -N acts as an electron donor to reduce NO2. - -N generates nitrogen gas. However, due to NH4 + -N is converted to NO2 under the action of AOB. - After being converted to nitrogen (NO3), it is easily further oxidized to nitrate nitrogen (NO3) by nitrite-oxidizing bacteria (NOB). - Therefore, suppressing NOB is key to achieving stable nitrite formation. Currently, common methods involve controlling free ammonia (FA), free nitrite (FNA), and dissolved oxygen (DO) within certain ranges to suppress NOB while simultaneously making ammonia-free bacteria (AOB) the dominant microorganism, thus achieving NO2 reduction. - Stable accumulation. PN / A denitrification technology has significant advantages over traditional nitrification-denitrification denitrification methods, such as saving energy consumption, eliminating the need for external organic carbon sources, and reducing sludge production.

[0003] Sulfate-type anaerobic ammonium oxidation (S-anammox): In a completely autotrophic inorganic environment, sulfate-type anaerobic ammonium oxidizing bacteria can oxidize SO42-. 2- -S is an oxidizing agent that reacts with NH4 + -N is oxidized to NO2 - -N is then subjected to an anaerobic ammonia oxidation reaction, ultimately producing elemental sulfur and N2. This process can simultaneously remove nitrogen and sulfur from wastewater, avoiding the problems of process instability and low removal efficiency when ammonia nitrogen and sulfate are treated separately. Moreover, elemental sulfur can be recovered during desulfurization, achieving resource recovery without generating secondary pollution.

[0004] Autotrophic denitrification (Canon): This process refers to the denitrification process achieved by controlling dissolved oxygen concentration within a single reactor or biofilm through nitrification and anaerobic ammonia oxidation. Since both AOB and AnAOB are autotrophic bacteria, the Canon reaction requires no external organic matter and can operate in a completely inorganic environment. However, because AOB is aerobic and AnAOB is anaerobic, the Canon reaction must be carried out in a low-oxygen environment. This process solves the problems of high operating costs, large sludge production, and high energy consumption associated with traditional nitrification-denitrification denitrification processes, while reducing aeration volume by approximately 60%.

[0005] However, in practical applications, using materials with ammonia nitrogen adsorption properties, such as zeolite or synthetic zeolite, as packing materials in biological fluidized beds, biological filters, or biological rotating discs can achieve stable nitrification. But in long-term operation, it has been found that backwashing is necessary to prevent zeolite caking and clogging. Furthermore, the frequency of backwashing increases with operating time, easily damaging the biofilm attached to the packing material and severely affecting its nitrification performance.

[0006] Therefore, providing a nitrification device that does not require backwashing has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] The purpose of this invention is to provide an autotrophic denitrification reactor, its preparation method and application. The autotrophic denitrification reactor provided by this invention has stable autotrophic denitrification performance during long-term treatment of ammonia nitrogen-containing wastewater.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing an autotrophic denitrification reactor, comprising the following steps: (1) Ammonia nitrogen adsorption material is filled into suspended spheres to obtain porous spherical packing material; (2) The porous spherical packing obtained in step (1) is placed into the reactor, and then ammonia nitrogen-containing wastewater is introduced. Then, nitrifying sludge is inoculated for the first biological acclimatization to obtain a reactor with nitrification characteristics. (3) Introduce ammonia nitrogen-containing wastewater into the reactor with nitrification characteristics obtained in step (2), and then inoculate it with anaerobic ammonia oxidation sludge for a second acclimatization to obtain an autotrophic denitrification reactor.

[0009] Preferably, the ammonia nitrogen adsorbent in step (1) is zeolite, maifanite, or artificially synthesized adsorbent with ammonia nitrogen adsorption properties, and the particle size of the ammonia nitrogen adsorbent is 1~5mm.

[0010] Preferably, in step (1), the amount of ammonia nitrogen adsorption material added is 60-90% of the internal volume of the suspension sphere.

[0011] Preferably, the ammonia nitrogen concentration of the ammonia nitrogen-containing wastewater in step (2) is 100~1000 mg / L.

[0012] Preferably, the ratio of the mass of the nitrifying sludge to the volume of the ammonia nitrogen-containing wastewater in the reactor in step (2) is 0.2~50 g / L.

[0013] Preferably, in step (2), the concentration of dissolved oxygen in the ammonia nitrogen-containing wastewater during the first biological acclimatization is 1.0~4.0 mg / L, the temperature of the first biological acclimatization is 15~40℃, and the total time of the first biological acclimatization is 5~30 days.

[0014] Preferably, in step (3), the concentration of dissolved oxygen in the ammonia nitrogen-containing wastewater during the second biological acclimatization is ≤1.0 mg / L, the temperature of the second biological acclimatization is 15~40℃, and the time of the second biological acclimatization is 15~45 days.

[0015] The present invention provides an autotrophic denitrification reactor prepared by the preparation method described in the above technical solution.

[0016] Preferably, the autotrophic denitrification reactor includes a reactor; An air inlet is provided at the bottom of the reactor; the air inlet is connected to an air pump; The reactor has an inlet located near the bottom; the inlet is connected to a water tank via a pipe; a flow meter and a water pump are sequentially installed on the pipe between the inlet and the water tank, with the flow meter located near the inlet and the water pump located near the water tank. A pad is provided in the reaction zone of the reactor; the upper part of the pad is a packing zone for placing porous spherical packing; the lower part of the pad is an inlet zone for ammonia nitrogen-containing wastewater. The reactor is equipped with a water outlet at the top.

[0017] The present invention provides the application of the autotrophic denitrification reactor described above in the treatment of ammonia nitrogen-containing wastewater. The preferred parameters for the treatment include: the ammonia nitrogen concentration in the ammonia nitrogen-containing wastewater is 100~1000 mg / L, the dissolved oxygen concentration in the ammonia nitrogen-containing wastewater is 1.0~4.0 mg / L, and the treatment temperature is 15~40℃.

[0018] The present invention provides a method for preparing an autotrophic denitrification reactor, comprising the following steps: (1) filling ammonia nitrogen adsorption material into suspended spheres to obtain porous spherical packing; (2) placing the porous spherical packing obtained in step (1) into a reactor, then introducing ammonia nitrogen-containing wastewater, followed by inoculating nitrifying sludge for the first biological acclimation, to obtain a reactor with nitrification characteristics; (3) introducing ammonia nitrogen-containing wastewater into the reactor with nitrification characteristics obtained in step (2), followed by inoculating anaerobic ammonia oxidation sludge for the second acclimation, to obtain an autotrophic denitrification reactor. This invention improves the adsorption capacity of ammonia nitrogen by installing ammonia nitrogen adsorption material into suspended spheres to form porous spherical packing. Through biological domestication, a large amount of biofilm is formed on the porous spherical packing. The biofilm mainly consists of nitrifying bacteria and anaerobic ammonia oxidizing bacteria. Since nitrifying bacteria consume a large amount of dissolved oxygen during the conversion of ammonia nitrogen, an anaerobic or even anaerobic environment exists on the biofilm surface, providing basic conditions for the growth of anaerobic ammonia oxidizing bacteria. During their metabolic denitrification process, anaerobic ammonia oxidizing bacteria secrete a large amount of extracellular polymers, gradually expanding the anaerobic microenvironment. Therefore, by controlling the dissolved oxygen concentration in the water, both bacterial communities can be maintained to grow simultaneously on the biofilm on the zeolite surface, jointly completing the conversion and removal of ammonia nitrogen, forming a synergistic denitrification effect. The domesticated porous spherical packing is transplantable and inoculated, with a short denitrification recovery period, enabling unitized and large-scale applications. The results of the embodiments show that the autotrophic denitrification reactor provided by this invention, after 45 days of operation, possesses stable autotrophic denitrification performance for NH4+ in ammonia-containing wastewater. + It has a strong buffering capacity against fluctuations in -N concentration and achieves stable denitrification. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the porous spherical packing provided by the present invention; Figure 2 This is a schematic diagram of the structure of the autotrophic denitrification reactor provided by the present invention. Detailed Implementation

[0020] This invention provides a method for preparing an autotrophic denitrification reactor, comprising the following steps: (1) Ammonia nitrogen adsorption material is filled into suspended spheres to obtain porous spherical packing material; (2) The porous spherical packing obtained in step (1) is placed into the reactor, and then ammonia nitrogen-containing wastewater is introduced. Then, nitrifying sludge is inoculated for the first biological acclimatization to obtain a reactor with nitrification characteristics. (3) Introduce ammonia nitrogen-containing wastewater into the reactor with nitrification characteristics obtained in step (2), and then inoculate it with anaerobic ammonia oxidation sludge for a second acclimatization to obtain an autotrophic denitrification reactor.

[0021] Unless otherwise specified, the raw materials used in this invention are not specifically limited and commercially available products known to those skilled in the art can be used.

[0022] This invention fills ammonia nitrogen adsorption material into suspended spheres to obtain porous spherical packing material.

[0023] In this invention, the ammonia nitrogen adsorbent is preferably zeolite, maifanite, or a synthetically produced adsorbent with ammonia nitrogen adsorption properties; the particle size of the ammonia nitrogen adsorbent is preferably 1-5 mm. This invention, by employing the above-mentioned ammonia nitrogen adsorbent, possesses excellent adsorption characteristics, which is beneficial for improving the adsorption efficiency of ammonia nitrogen.

[0024] In this invention, the suspended sphere is preferably composed of two interlocking hemispherical materials with porous surfaces and hollow interiors; the diameter of the suspended sphere is preferably 50-150 mm. This invention does not have a specific limitation on the pore size of the porous structure on the surface of the hemispherical materials, as long as it prevents the ammonia nitrogen adsorbent material from being removed from the suspended sphere. By using the above-mentioned suspended sphere, this invention facilitates the filling and use of the ammonia nitrogen adsorbent material.

[0025] In this invention, the amount of ammonia nitrogen adsorbent added is preferably 60-90% of the internal volume of the suspended spheres. As one embodiment of this invention, the amount of ammonia nitrogen adsorbent added is preferably 60%, 65%, 70%, 75%, 80%, 85%, or 90% of the internal volume of the suspended spheres. By controlling the amount of ammonia nitrogen adsorbent added, this invention can increase the adsorbable area inside the porous spherical packing.

[0026] This invention does not impose any special limitations on the specific operation of filling the ammonia nitrogen adsorbent material into the suspended spheres; conventional filling methods are sufficient. By filling the ammonia nitrogen adsorbent material into the suspended spheres, this invention facilitates the concentration of ammonia nitrogen during subsequent adsorption, making subsequent recycling and reuse easier.

[0027] A schematic diagram of the porous spherical packing provided by this invention is shown below. Figure 1 As shown. By Figure 1 As can be seen, the ammonia nitrogen adsorption material in the porous spherical packing provided by the present invention is filled in the suspended spheres.

[0028] After obtaining the porous spherical packing material, the present invention puts the porous spherical packing material into a reactor, then introduces ammonia nitrogen-containing wastewater, and then inoculates nitrifying sludge for the first biological acclimatization, thereby obtaining a reactor with nitrification characteristics.

[0029] In this invention, the ammonia nitrogen concentration of the ammonia-containing wastewater is preferably 100-1000 mg / L. In this invention, when the ammonia nitrogen concentration of the ammonia-containing wastewater does not meet the above requirements, pretreatment of the ammonia-containing wastewater is preferred. This invention does not have specific limitations on the specific operation of the pretreatment, as long as it can make the ammonia nitrogen concentration of the ammonia-containing wastewater meet the above requirements. As one embodiment of this invention, the ammonia nitrogen concentration of the ammonia-containing wastewater can be 100 mg / L, 150 mg / L, 200 mg / L, 250 mg / L, 300 mg / L, 350 mg / L, 400 mg / L, 450 mg / L, 500 mg / L, 550 mg / L, 600 mg / L, 650 mg / L, 700 mg / L, 750 mg / L, 800 mg / L, 850 mg / L, 900 mg / L, 950 mg / L, or 1000 mg / L. This invention promotes the growth of nitrifying bacteria by controlling the ammonia nitrogen concentration in ammonia nitrogen-containing wastewater, thereby forming a biofilm.

[0030] In this invention, the preferred ratio of the mass of the nitrifying sludge to the volume of ammonia-nitrogen-containing wastewater in the reactor is 0.2~50 g / L. As one embodiment of this invention, the ratio of the mass of the nitrifying sludge to the volume of ammonia-nitrogen-containing wastewater in the reactor can be 0.2 g / L, 0.5 g / L, 1 g / L, 2 g / L, 3 g / L, 5 g / L, 8 g / L, 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L, or 50 g / L. This invention, by controlling the amount of nitrifying sludge added, promotes the growth of nitrifying bacteria.

[0031] In this invention, the concentration of dissolved oxygen in the ammonia-nitrogen-containing wastewater during the first biological acclimatization is preferably 1.0~4.0 mg / L; the temperature of the first biological acclimatization is preferably 15~40℃. As one embodiment of this invention, the concentration of dissolved oxygen in the ammonia-nitrogen-containing wastewater during the first biological acclimatization can be 1.0 mg / L, 1.5 mg / L, 2.0 mg / L, 2.5 mg / L, 3.0 mg / L, 3.2 mg / L, 3.5 mg / L, 3.8 mg / L, or 4.0 mg / L; the temperature of the first biological acclimatization can be 15℃, 20℃, 25℃, 30℃, 35℃, or 40℃.

[0032] In this invention, the preferred method for the first biological acclimatization is to acclimatize for 1-2 days, followed by continuous influent of ammonia-nitrogen-containing wastewater until the effluent ammonia nitrogen conversion rate reaches over 90%, at which point acclimatization is complete. The preferred total time for the first biological acclimatization is 5-30 days. As one embodiment of this invention, the total time for the first biological acclimatization can be 5, 8, 10, 12, 15, 18, 20, 22, 25, 28, or 30 days. By employing the above-described method for biological acclimatization, this invention can form a biofilm on the surface of the porous spherical packing material and the internal ammonia nitrogen adsorption material.

[0033] In this invention, the first biological acclimatization process preferably also includes adjusting alkalinity; the method of adjusting alkalinity is preferably to add an alkaline component to maintain the pH value of the ammonia nitrogen-containing wastewater at 7.0-8.5, more preferably at 7.5-8.0; the alkaline component is preferably sodium hydroxide, sodium carbonate, or sodium bicarbonate. This invention does not have a specific limitation on the amount of the alkaline component added, as long as the pH value of the ammonia nitrogen-containing wastewater meets the requirements. By adjusting alkalinity, this invention can maintain the pH value of the ammonia nitrogen-containing wastewater within a suitable range, thereby promoting the reproduction of microorganisms.

[0034] In this invention, the nitrification ratio in the reactor with nitrification characteristics is preferably 45-60%. As one embodiment of this invention, the nitrification ratio in the reactor with nitrification characteristics is preferably 45%, 50%, 55%, or 60%. In this invention, the nitrification ratio of 45-60% in the reactor with nitrification characteristics refers to a final effluent nitrite nitrogen to ammonia nitrogen mass concentration ratio of 0.5-1.3. This invention, by controlling the nitrification ratio, facilitates the subsequent biological acclimatization of anaerobic ammonia-oxidizing bacteria.

[0035] After obtaining a reactor with nitrification characteristics, the present invention introduces ammonia nitrogen-containing wastewater into the reactor with nitrification characteristics, and then inoculates it with anaerobic ammonia oxidation sludge for a second acclimation to obtain an autotrophic denitrification reactor.

[0036] In this invention, the anammox sludge is preferably seed sludge taken from an anammox denitrification device operating normally under laboratory conditions. This invention introduces anammox bacteria into the reactor by inoculating the anammox sludge.

[0037] In this invention, the ammonia nitrogen concentration of the ammonia-containing wastewater is preferably 100-1000 mg / L. In this invention, when the ammonia nitrogen concentration of the ammonia-containing wastewater does not meet the above requirements, pretreatment of the ammonia-containing wastewater is preferred. This invention does not impose any special limitations on the specific operation of the pretreatment, as long as it can make the ammonia nitrogen concentration of the ammonia-containing wastewater meet the above requirements. As one embodiment of this invention, the ammonia nitrogen concentration of the ammonia-containing wastewater can be 100 mg / L, 150 mg / L, 200 mg / L, 250 mg / L, 300 mg / L, 350 mg / L, 400 mg / L, 450 mg / L, 500 mg / L, 550 mg / L, 600 mg / L, 650 mg / L, 700 mg / L, 750 mg / L, 800 mg / L, 850 mg / L, 900 mg / L, 950 mg / L, or 1000 mg / L. This invention promotes the growth of anaerobic ammonia-oxidizing bacteria by controlling the ammonia nitrogen concentration in ammonia-containing wastewater.

[0038] In this invention, the preferred ratio of the mass of the anammox sludge to the volume of ammonia-nitrogen-containing wastewater in the reactor is 0.2~50 g / L. As one embodiment of this invention, the ratio can be 0.2 g / L, 0.5 g / L, 1 g / L, 2 g / L, 3 g / L, 5 g / L, 8 g / L, 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L, or 50 g / L. This invention, by controlling the amount of anammox sludge added, promotes the growth of anammox bacteria.

[0039] In this invention, the concentration of dissolved oxygen in the ammonia-nitrogen-containing wastewater during the second biological acclimatization is preferably ≤1.0 mg / L, more preferably 0.1~1.0 mg / L; the temperature of the second biological acclimatization is preferably 15~40℃; and the duration of the second biological acclimatization is preferably 15~45 days. As one embodiment of this invention, the concentration of dissolved oxygen in the ammonia-nitrogen-containing wastewater during the second biological acclimatization can be 0.1 mg / L, 0.2 mg / L, 0.3 mg / L, 0.4 mg / L, 0.5 mg / L, 0.6 mg / L, 0.7 mg / L, 0.8 mg / L, 0.9 mg / L, or 1.0 mg / L; the temperature of the second biological acclimatization can be 15℃, 20℃, 25℃, 30℃, 35℃, or 40℃; and the duration of the second biological acclimatization can be 15 days, 20 days, 25 days, 30 days, 35 days, 40 days, or 45 days. By employing the above-described method for biological domestication, this invention can form a biofilm on the surface of the ammonia nitrogen adsorption material and the surface of the internal ammonia nitrogen adsorption material.

[0040] In this invention, the second biological acclimatization process preferably also includes alkalinity regulation; the preferred method for alkalinity regulation is to reduce dissolved oxygen to decrease the continuous consumption of alkalinity by nitrification or to maintain the pH of the ammonia nitrogen-containing wastewater at 7.0-8.5 by adding exogenous alkaline components, more preferably maintaining the pH at 7.5-8.0; the alkaline component is preferably sodium hydroxide, sodium carbonate, or sodium bicarbonate. This invention does not have a specific limitation on the amount of alkaline component added, as long as the pH of the ammonia nitrogen-containing wastewater meets the requirements. By regulating alkalinity, this invention can maintain the pH of the ammonia nitrogen-containing wastewater within a suitable range, thereby providing suitable alkaline conditions for anaerobic ammonia-oxidizing bacteria.

[0041] This invention improves the adsorption capacity of ammonia nitrogen by installing ammonia nitrogen adsorption material into suspended spheres to form porous spherical packing. Through biological domestication, a large amount of biofilm is formed on the porous spherical packing. The biofilm mainly consists of nitrifying bacteria and anaerobic ammonia oxidizing bacteria. Since the nitrifying bacteria consume a large amount of dissolved oxygen during the conversion of ammonia nitrogen, there is a hypoxic or even anaerobic environment on the surface of the biofilm, which provides the basic conditions for the growth of anaerobic ammonia oxidizing bacteria. During the denitrification process, anaerobic ammonia oxidizing bacteria secrete a large amount of extracellular polymers and gradually expand the anaerobic microenvironment. Therefore, by controlling the dissolved oxygen concentration in the water, both bacterial groups can be maintained to grow together on the biofilm on the zeolite surface, jointly completing the conversion and removal of ammonia nitrogen and forming a synergistic denitrification effect. The porous spherical packing in the domesticated autotrophic denitrification reactor can be transplanted and inoculated, and has a short denitrification recovery cycle, enabling unitized and large-scale application.

[0042] The present invention also provides an autotrophic denitrification reactor prepared by the preparation method described in the above technical solution.

[0043] The preferred structural schematic diagram of the autotrophic denitrification reactor provided by the present invention is shown below. Figure 2 As shown.

[0044] like Figure 2 As shown, in one embodiment of the present invention, the autotrophic denitrification reactor includes a reactor; An air inlet is provided at the bottom of the reactor; the air inlet is connected to an air pump; The reactor has an inlet located near the bottom; the inlet is connected to a water tank via a pipe; a flow meter and a water pump are sequentially installed on the pipe between the inlet and the water tank, with the flow meter located near the inlet and the water pump located near the water tank. A pad is provided in the reaction zone of the reactor; the upper part of the pad is a packing zone for placing porous spherical packing; the lower part of the pad is an inlet zone for ammonia nitrogen-containing wastewater. The reactor is equipped with a water outlet at the top.

[0045] like Figure 2 As shown, in one embodiment of the present invention, the reactor is preferably cylindrical. The present invention does not impose any special limitations on the size of the reactor; it can be determined based on the technical knowledge of those skilled in the art.

[0046] like Figure 2 As shown, in one embodiment of the present invention, the ammonia-nitrogen-containing wastewater in the inlet tank is introduced into the reaction zone of the reactor by an inlet pump, and then the amount of ammonia-nitrogen-containing wastewater introduced is controlled by a flow meter.

[0047] like Figure 2 As shown, in one embodiment of the present invention, gas is introduced into the reactor from the bottom via an air pump. By utilizing an air pump to introduce gas into the reactor, the present invention can control the dissolved oxygen content of the ammonia-nitrogen-containing wastewater in the reactor, thereby promoting the growth and reproduction of microorganisms.

[0048] like Figure 2 As shown, in one embodiment of the present invention, the pad is preferably located in the lower middle part of the reaction zone in the reactor; the pad is preferably provided with holes; the diameter of the holes is preferably smaller than the diameter of the porous spherical packing. The present invention does not have a special limitation on the specific location of the pad; based on the technical knowledge of those skilled in the art, it is sufficient to divide the reactor into upper and lower parts, and the upper part can be fitted with a sufficient amount of porous spherical packing. The present invention does not have a special limitation on the number of holes on the pad; based on the technical knowledge of those skilled in the art, it is sufficient to allow water from the bottom of the reactor to smoothly enter the upper part. In one embodiment of the present invention, the volume of the upper part of the pad is preferably 55-75% of the total volume of the reactor, more preferably 60-70%. The present invention divides the reactor into upper and lower parts using the pad. The lower part introduces ammonia-nitrogen-containing wastewater with a dissolved oxygen content meeting the requirements through the water inlet and air inlet. Then, as the ammonia-nitrogen-containing wastewater passes through the upper part of the reactor, it comes into contact with the porous spherical packing installed in the upper part of the reactor, thereby achieving ammonia nitrogen removal.

[0049] In this invention, the autotrophic denitrification reactor is preferably used for the removal of ammonia nitrogen-containing wastewater.

[0050] In this invention, the ammonia nitrogen concentration of the ammonia-containing wastewater is preferably 100-1000 mg / L; the pH value of the ammonia-containing wastewater is preferably 7.0-9.5. In this invention, when the ammonia nitrogen concentration and pH value of the ammonia-containing wastewater do not meet the above requirements, pretreatment of the ammonia-containing wastewater is preferred. This invention does not impose any special limitations on the specific operation of the pretreatment, as long as it enables the ammonia nitrogen concentration and pH value of the ammonia-containing wastewater to meet the above requirements. In one embodiment of the present invention, the ammonia nitrogen concentration of the ammonia-containing wastewater can be 100 mg / L, 150 mg / L, 200 mg / L, 250 mg / L, 300 mg / L, 350 mg / L, 400 mg / L, 450 mg / L, 500 mg / L, 550 mg / L, 600 mg / L, 650 mg / L, 700 mg / L, 750 mg / L, 800 mg / L, 850 mg / L, 900 mg / L, 950 mg / L, or 1000 mg / L; the pH value of the ammonia-containing wastewater can be 7.0, 7.2, 7.5, 7.8, 8.0, 8.2, 8.5, 8.8, 9.0, 9.2, or 9.5. By controlling the ammonia nitrogen concentration and pH value in the ammonia-containing wastewater, the present invention enables the porous spherical packing to fully exert its denitrification performance.

[0051] This invention utilizes the favorable hydraulic distribution conditions of suspended spheres and optimizes the acclimation strategy to acclimate them into an integrated device with autotrophic denitrification function. By designing the autotrophic denitrification reactor with suspended spheres, the gas-water mass transfer rate is improved while avoiding zeolite caking and biofilm shedding caused by backwashing, thus promoting stable denitrification in the reactor. By acclimating the suspended spheres with autotrophic denitrification function, compared with traditional autotrophic denitrification devices, it buffers the fluctuation of influent ammonia nitrogen load, improving its operational stability. The autotrophic denitrification reactor provided by this invention has a simple operation method and reduces the footprint and operation steps compared with the traditional "step-by-step" partial nitrification-anaerobic ammonia oxidation denitrification device.

[0052] The present invention also provides the application of the autotrophic denitrification reactor described in the above technical solution in the treatment of ammonia nitrogen-containing wastewater.

[0053] In this invention, the preferred parameters for the treatment include: an ammonia nitrogen concentration of 100-1000 mg / L in the ammonia nitrogen-containing wastewater, a dissolved oxygen concentration of 1.0-4.0 mg / L in the ammonia nitrogen-containing wastewater, and a treatment temperature of 15-40°C. In one embodiment of the present invention, the ammonia nitrogen concentration of the ammonia nitrogen-containing wastewater can be 100 mg / L, 150 mg / L, 200 mg / L, 250 mg / L, 300 mg / L, 350 mg / L, 400 mg / L, 450 mg / L, 500 mg / L, 550 mg / L, 600 mg / L, 650 mg / L, 700 mg / L, 750 mg / L, 800 mg / L, 850 mg / L, 900 mg / L, 950 mg / L, or 1000 mg / L; the dissolved oxygen concentration of the ammonia nitrogen-containing wastewater can be 1.0 mg / L, 1.5 mg / L, 2.0 mg / L, 2.5 mg / L, 3.0 mg / L, 3.5 mg / L, or 4.0 mg / L; and the treatment temperature can be 15℃, 20℃, 25℃, 30℃, 35℃, or 40℃.

[0054] This invention, by controlling the parameters of the application, can reduce the NH4 content in treated water. + -N, NO2 - -N and NO3 - -N was stably maintained at 30~50 mg / L, 10~30 mg / L, and 30~50 mg / L, respectively, while the autotrophic denitrification reactor exhibited stable autotrophic denitrification performance, effectively removing NH4+ from ammonia-containing wastewater. + It has a strong buffering capacity against fluctuations in -N concentration and achieves stable denitrification.

[0055] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0056] Example 1 A method for preparing an autotrophic denitrification reactor comprises the following steps: (1) Ammonia nitrogen adsorbent material is filled into suspended spheres to obtain porous spherical packing material; the ammonia nitrogen adsorbent material is zeolite with a particle size of 3~5mm; the suspended sphere is composed of two interlocking hemispherical materials with porous surfaces and hollow interiors, and the diameter of the suspended sphere is 50mm; the amount of zeolite added is 80% of the internal volume of the porous spherical packing material; (2) The porous spherical packing material obtained in step (1) is placed into the reactor, and then wastewater containing ammonia nitrogen is introduced. Then, nitrifying sludge is inoculated for the first biological acclimatization to obtain a reactor with nitrification characteristics. At this time, NH4 in the effluent + -N, NO2 - -N and NO3 - The concentrations of -N were stable at 40–50 mg / L, 10–20 mg / L, and 15–20 mg / L, respectively. The porous spherical packing material in the reactor adsorbed NH4+. + The reactor utilizes both nitrogen (N) and biofilm conversion of ammonia nitrogen, operating simultaneously. It is constructed from cylindrical transparent acrylic material, with a reaction zone height of 1400 mm, an inner diameter of 100 mm, and a total volume of approximately 11 L. A plate divides the reactor into an upper packing zone and a lower ammonia-containing wastewater inlet zone, with the packing zone having a volume of approximately 7 L. The ammonia nitrogen concentration in the wastewater is 200 mg / L. The ratio of the mass of the nitrifying sludge to the volume of the ammonia-containing wastewater in the reactor is 10 g / L. During the first biological acclimation, the dissolved oxygen concentration in the ammonia-containing wastewater is 4.0 mg / L, and the temperature is 25°C. The first biological acclimation involves two days of initial acclimation, followed by continuous feeding of ammonia-containing wastewater. The total duration of the first biological acclimation is 15 days. Sodium carbonate is used to regulate alkalinity during the first biological acclimation process, maintaining the pH of the ammonia-containing wastewater between 7.5 and 8.5. (3) Ammonia-containing wastewater is introduced into the reactor with nitrification characteristics obtained in step (2), followed by inoculation with anaerobic ammonia oxidation sludge for a second acclimation, resulting in an autotrophic denitrification reactor. At this point, the NH4+ in the effluent... + -N, NO2 - -N and NO3 - -N was stably maintained at 50~60 mg / L, 10~15 mg / L and 20~40 mg / L respectively, and the NH4+ in the reactor was... + Nitrogen removal is primarily achieved through nitrification, accompanied by anaerobic ammonia oxidation (AAO). The AAO sludge is seed sludge taken from an AAO denitrification device operating normally under laboratory conditions. The ammonia nitrogen concentration in the wastewater is 250 mg / L. The mass ratio of the AAO sludge to the volume of the wastewater in the reactor is 5 g / L. During the second biological acclimation, the dissolved oxygen concentration in the wastewater is <1.0 mg / L, the temperature is 25℃, and the acclimation period is 30 days. Sodium carbonate is used to regulate alkalinity during the second biological acclimation process, maintaining the pH of the wastewater at 7.5–8.5.

[0057] Application Example 1 The autotrophic denitrification reactor provided in Example 1 was used to treat ammonia nitrogen-containing wastewater. During treatment, the NH4+ in the ammonia nitrogen-containing wastewater was reduced. + The ammonia nitrogen concentration is 300 mg / L, the dissolved oxygen concentration of the ammonia nitrogen-containing wastewater is 1.5 ± 0.5 mg / L, the treatment temperature is 25℃, and the treatment time is 45 days. At this time, the NH4+ concentration in the effluent... + -N, NO2 - -N and NO3 - -N was stably maintained at 30~50 mg / L, 10~30 mg / L and 30~50 mg / L, respectively.

[0058] As can be seen from Application Example 1, the autotrophic denitrification reactor provided by this invention exhibits stable autotrophic denitrification performance after 45 days of operation, effectively removing NH4 from ammonia-containing wastewater. + It has a strong buffering capacity against fluctuations in -N concentration and achieves stable denitrification.

[0059] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an autotrophic denitrification reactor, characterized in that, Includes the following steps: (1) Ammonia nitrogen adsorption material is filled into suspended spheres to obtain porous spherical packing material; (2) The porous spherical packing obtained in step (1) is placed into the reactor, and then ammonia nitrogen-containing wastewater is introduced. Then, nitrifying sludge is inoculated for the first biological acclimatization to obtain a reactor with nitrification characteristics. (3) Introduce ammonia nitrogen-containing wastewater into the reactor with nitrification characteristics obtained in step (2), and then inoculate it with anaerobic ammonia oxidation sludge for a second acclimatization to obtain an autotrophic denitrification reactor.

2. The preparation method according to claim 1, characterized in that, In step (1), the ammonia nitrogen adsorbent is zeolite, maifanite, or artificially synthesized adsorbent with ammonia nitrogen adsorption properties, and the particle size of the ammonia nitrogen adsorbent is 1~5mm.

3. The preparation method according to claim 1, characterized in that, In step (1), the amount of ammonia nitrogen adsorption material added is 60-90% of the internal volume of the suspension sphere.

4. The preparation method according to claim 1, characterized in that, The ammonia nitrogen concentration in the ammonia nitrogen-containing wastewater in step (2) is 100~1000 mg / L.

5. The preparation method according to claim 1, characterized in that, In step (2), the ratio of the mass of the nitrifying sludge to the volume of the ammonia nitrogen-containing wastewater in the reactor is 0.2~50 g / L.

6. The preparation method according to claim 1, characterized in that, In step (2), the concentration of dissolved oxygen in the ammonia nitrogen wastewater during the first biological acclimatization is 1.0~4.0 mg / L, the temperature of the first biological acclimatization is 15~40℃, and the total time of the first biological acclimatization is 5~30 days.

7. The preparation method according to claim 1, characterized in that, In step (3), the concentration of dissolved oxygen in the ammonia nitrogen wastewater during the second biological acclimatization is ≤1.0 mg / L, the temperature of the second biological acclimatization is 15~40℃, and the time of the second biological acclimatization is 15~45 days.

8. An autotrophic denitrification reactor prepared by the preparation method according to any one of claims 1 to 7.

9. The autotrophic denitrification reactor according to claim 8, characterized in that, The autotrophic denitrification reactor includes a reactor; An air inlet is provided at the bottom of the reactor; the air inlet is connected to an air pump; The reactor has an inlet located near the bottom; the inlet is connected to a water tank via a pipe; a flow meter and a water pump are sequentially installed on the pipe between the inlet and the water tank, with the flow meter located near the inlet and the water pump located near the water tank. A pad is provided in the reaction zone of the reactor; the upper part of the pad is a packing zone for placing porous spherical packing; the lower part of the pad is an inlet zone for ammonia nitrogen-containing wastewater. The reactor is equipped with a water outlet at the top.

10. The application of the autotrophic denitrification reactor according to any one of claims 8 to 9 in the treatment of ammonia nitrogen-containing wastewater, characterized in that, The preferred parameters for the treatment include: an ammonia nitrogen concentration of 100-1000 mg / L in the ammonia nitrogen-containing wastewater, a dissolved oxygen concentration of 1.0-4.0 mg / L in the ammonia nitrogen-containing wastewater, and a treatment temperature of 15-40℃.

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