Magnetic simultaneous nitrification denitrification carrier and preparation method thereof

Abstract

The application relates to a magnetic synchronous nitrification and denitrification carrier and a preparation method thereof. The carrier comprises a core body comprising an inner core and a magnetic powder film; the inner core is formed of HDPE, and the magnetic powder film is formed of magnetic powder adhered to the surface layer of the inner core; and a fiber film is wrapped on the surface of the core body. The preparation method comprises the following steps: melting HDPE into a sheet shape under the condition of 150-200 DEG C; adding pure water into the magnetic powder to mix, the ratio of the magnetic powder to the water is 20:1-2000:1, and a mixture of the magnetic powder and the water is obtained; placing the melted sheet-shaped HDPE into the mixture, heating to 180 DEG C, maintaining for 2-5 minutes, and then cooling and taking out to obtain the core body; winding the fiber film on the core body; and placing the wound core body in a magnetic field environment with a magnetic field intensity of more than 1T, applying vibration at the same time, and staying for more than 10 seconds to complete the preparation of the carrier. The application can effectively form nitrification and denitrification regions on the surface of the carrier by wrapping a layer of fiber film on the surface of the core body, so that the carbon source in the water body is effectively utilized to realize synchronous nitrification and denitrification denitrification.

Description

Technical Field

[0001] This invention belongs to the field of microbial water treatment technology, specifically relating to a magnetic synchronous nitrification and denitrification carrier and its preparation method. Background Technology

[0002] Currently, effective nitrogen treatment for groundwater nitrogen pollution is a pressing problem that needs to be solved. Microbial denitrification is a low-cost method, and current wastewater denitrification mainly relies on nitrification and denitrification technologies. According to traditional biological denitrification theory, the denitrification pathway generally includes two stages: nitrification and denitrification. These two processes need to be carried out in two isolated reactors, or in the same reactor where alternating anoxic and aerobic environments are created in time or space. This technology is relatively slow. If the goal is to effectively utilize the water body's own carbon source, sludge and effluent recirculation is required, resulting in high treatment costs and a large land area.

[0003] In recent years, non-assimilation loss of nitrogen has been repeatedly observed in activated sludge processes without obvious anoxic or anaerobic stages, and nitrogen disappearance has also been observed multiple times in aeration systems. In these treatment systems, nitrification and denitrification reactions often occur under the same treatment conditions and within the same treatment space; this process is called simultaneous nitrification and denitrification. However, simultaneous nitrification and denitrification is difficult to control, and current technologies have the following problems or drawbacks: A. Dissolved oxygen is difficult to control. Due to limitations in instrument accuracy, dissolved oxygen data varies significantly at different locations and depths within the tank, resulting in lag and inaccuracy in data detection and control, making it difficult to control operating conditions. B. Simultaneous nitrification and denitrification typically employ intermittent aeration, which significantly affects the reaction, leading to poor mixing of sludge and water and insufficient reaction between microorganisms and wastewater.

[0004] Therefore, achieving controllable, stable, and efficient simultaneous nitrification and denitrification reactions remains a major challenge. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a magnetic synchronous nitrification and denitrification carrier and its preparation method, thereby improving the growth rate of nitrifying and denitrifying bacteria, optimizing their spatial distribution on the carrier surface, increasing the utilization efficiency of carbon sources in the water during the denitrification process, and ensuring the stable operation of the synchronous nitrification and denitrification process.

[0006] The present invention adopts the following technical solution.

[0007] On one hand, the present invention provides a magnetic synchronous nitrification-denitrification carrier. The magnetic synchronous nitrification-denitrification carrier comprises: a core body, which is prepared from HDPE and magnetic powder; the HDPE and the magnetic powder are in the following proportions by weight: 1-10 parts magnetic powder and 90-98 parts HDPE; and a fiber membrane covering the surface of the core body.

[0008] Preferably, the core comprises an inner core and a magnetic powder film; the inner core is formed of HDPE, and the magnetic powder film is formed of magnetic powder adhered to the surface of the inner core.

[0009] Preferably, the magnetic powder is a specific magnetite powder; the specific magnetite powder has a purity of over 98% for magnetite with an inverse spinel structure.

[0010] Preferably, the specific ferric oxide is prepared by the following steps: Step 101, the ferric oxide raw material is placed in a container and then placed in a magnetic field environment of 0.5-1T, and impurities are removed by vibration sieving; Step 102, pure water is added to the vibrated ferric oxide, and after thorough stirring, it is heated to 350-600℃ and maintained for at least 10 minutes to obtain heated ferric oxide; Step 103, the heated ferric oxide is dried, taken out, ground, and passed through 200-mesh and 500-mesh sieves, and the ferric oxide powder between 200-mesh and 500-mesh is collected to obtain the specific ferric oxide.

[0011] Preferably, the fiber membrane is filter cotton, polyurethane sheet, or honeycomb polypropylene.

[0012] Preferably, the overall density of the filter cotton is between 0.96 and 0.98 t / m³. 3 The thickness of the fabric is 2 to 8 mm.

[0013] On the other hand, the present invention provides a method for preparing the above-mentioned magnetic synchronous nitrification-denitrification carrier. The method includes the following steps: Step 201, melting HDPE into flakes at 150-200°C; Step 202, adding pure water dropwise to magnetic powder for mixing, wherein the ratio of magnetic powder to water is 20:1 to 2000:1, to obtain a mixture of magnetic powder and water; Step 203, placing the melted flake HDPE into the mixture, heating to 180°C, so that the surface of the flake HDPE is uniformly coated with the magnetic powder, maintaining for 2-5 minutes, cooling and removing, to obtain the core; Step 204, winding a fiber membrane onto the core; Step 205, placing the wound core in a magnetic field environment of 1T or higher, simultaneously applying vibration and holding for more than 10 seconds, to complete the carrier preparation.

[0014] Preferably, step 201 further includes: melting HDPE into sheets with a corrugated cross-section at an environment of 150-200°C.

[0015] Preferably, step 203 further includes: placing the melted sheet HDPE into the mixture, heating it to above 180°C under a pressure of 1500-4000 Pa, maintaining it for 2-5 minutes, cooling it, and removing it to obtain the core.

[0016] Preferably, step 204 further includes: winding the fiber membrane onto the core under heating conditions.

[0017] The beneficial effects of this invention are compared with those of the prior art:

[0018] (1) By using magnetic powder to form a unique magnetic field distribution on the surface of the core, and at the same time coating the surface of the core with a layer of fiber membrane, the adhesion of microorganisms is improved, and they can also be stimulated and affected by the magnetic field, thereby improving the activity of denitrifying bacteria and creating a better hypoxic environment for denitrifying bacteria. This allows for the faster formation of a biofilm structure with nitrifying bacteria as the main component outside the fiber membrane and denitrifying bacteria as the main component inside the fiber membrane, so as to achieve the synchronous nitrification and denitrification process under the stimulation of the magnetic field.

[0019] (2) Pretreatment allows the iron oxide particles to be more evenly distributed on the HDPE surface, while grinding allows the particles to achieve a higher magnetic field strength with a very small amount of addition. Placing the carrier twice in a strong magnetic field environment can obtain a better magnetic field distribution, effectively improving the carrier's stimulation of nitrifying and denitrifying bacteria.

[0020] (3) Because the carrier has a sheet-like structure with an additional fibrous membrane on the outside, nitrification and denitrification zones can be formed more effectively on the carrier surface, making them more balanced and more efficient in utilizing carbon sources in the water to achieve simultaneous nitrification and denitrification. Meanwhile, the density of the carrier in this invention is 0.98 g / cm³. 3 The carrier can float well in the reactor and move with the aeration, making better contact with pollutants in the water and achieving efficient treatment of nitrogen pollutants.

[0021] (4) The materials used to prepare the carrier are simple, consisting only of specific iron(III) oxide and HDPE, and the raw materials are easy to obtain.

[0022] (5) The allowable range for dissolved oxygen (DO) concentration is very large. Due to the formation of a thick biofilm structure on the carrier, the magnetic core promotes the growth of internal denitrifying bacteria. Even if the dissolved oxygen in the external environment reaches above 2 mg / L, the internal concentration can still be maintained below 0.5 mg / L, thus maintaining and ensuring a relatively stable denitrification environment. Therefore, both intermittent and continuous aeration methods can meet the operating conditions for simultaneous nitrification and denitrification, ensuring the stable progress of the nitrification and denitrification process and making it easier to control the operating conditions. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the carrier morphology in this invention.

[0024] Figure 2 This describes the changes in COD and nitrate levels in the influent and effluent of the experimental and control groups in Example 1 of this invention.

[0025] Figure 3 This describes the changes in ammonia nitrogen in the influent and effluent of the experimental group and the control group in Example 1 of this invention.

[0026] Figure 4 The ammonia nitrogen removal load and simultaneous nitrification-denitrification rate are those of the experimental group and the control group in Example 1 of this invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, other embodiments obtained by those skilled in the art without creative effort are all within the protection scope of this invention.

[0028] In one aspect, the present invention provides a magnetic synchronous nitrification-denitrification carrier. The magnetic synchronous nitrification-denitrification carrier comprises a core and a fiber membrane coating the surface of the core. The core is prepared from HDPE (high-density polyethylene) and magnetic powder, wherein the HDPE and magnetic powder are in the following proportions by weight: 1-10 parts magnetic powder and 90-98 parts HDPE.

[0029] By coating the core with a fiber membrane, nitrification and denitrification zones can be formed more effectively on the core surface, achieving a better balance between the two and more efficient utilization of carbon sources in the water to achieve simultaneous nitrification and denitrification. Simultaneously, the core can stimulate and influence the microorganisms attached to the fiber membrane with a magnetic field, increasing the activity of denitrifying bacteria and accelerating the formation of a biofilm structure dominated by nitrifying bacteria on the outside and denitrifying bacteria on the inside, thus achieving simultaneous nitrification and denitrification processes under the stimulation of the magnetic field.

[0030] Furthermore, the core comprises an inner core and a magnetic powder film. The inner core is formed of HDPE, and the magnetic powder film is formed of magnetic powder adhered to the surface layer of the inner core.

[0031] By adhering a layer of magnetic powder film to the surface of HDPE, a higher magnetic field strength can be obtained with the least amount of magnetic powder added, compared to uniformly distributing the magnetic powder film in the HDPE core.

[0032] Preferably, the magnetic powder can be specific magnetite (Fe3O4). Specific magnetite refers to magnetite with an inverse spinel structure that does not contain other impurities. For example, the purity of specific magnetite with an inverse spinel structure is above 98%.

[0033] Specifically, this specific iron(III) oxide can be prepared by the following steps:

[0034] Step 101: Place the iron oxide raw material into a container and then place it in a magnetic field environment of 0.5 to 1T to remove impurities by vibration sieving.

[0035] In this step, placing the iron oxide raw material in a magnetic field environment helps to screen out impurities and prevent them from affecting the quality of the final carrier.

[0036] Step 102: Add pure water to the vibrated iron oxide, stir thoroughly, heat to 350-600°C, and maintain for at least 10 minutes to obtain heated iron oxide.

[0037] In this step, heating the mixture after thoroughly mixing the magnetic powder with pure water can alter the arrangement of the magnetic powder and simultaneously demagnetize it.

[0038] Step 103: After drying the heated iron oxide, take it out, grind it, and pass it through 200-mesh and 500-mesh sieves. Collect the iron oxide powder between 200-mesh and 500-mesh to obtain specific iron oxide.

[0039] In this step, grinding can be carried out in a mortar. By collecting magnetite between 200 and 500 mesh, the subsequent mixing effect of specific magnetite magnetic powder and HDPE can be improved. This is because excessively fine magnetic powder will make it difficult to achieve the required magnetic field strength, while excessively coarse magnetic powder will affect the uniform distribution of the powder.

[0040] The above preparation method can make the prepared specific iron oxide particles more uniformly distributed on the HDPE surface during the carrier preparation process.

[0041] In this invention, the fiber membrane can be made of non-woven filter cotton. Preferably, the overall density of the filter cotton is between 0.96 and 0.98 g / cm³. 3 The thickness of the fabric is 2 to 8 mm.

[0042] The filter cotton of the above specifications can achieve a low overall density. When the filter cotton is wrapped around the core surface, the total density of the carrier can be maintained at 0.98 g / cm³. 3 This allows the carrier to float well within the reactor, moving with the aeration process and making better contact with pollutants in the water, thus achieving efficient treatment of nitrogen pollutants.

[0043] Alternatively, the fiber membrane in this invention can also be made of polyurethane sheet (thickness within 3 mm), honeycomb polypropylene, etc.

[0044] In another aspect, the present invention also provides a method for preparing a magnetic synchronous nitrification-denitrification support. The method includes the following steps:

[0045] Step 201: Melt HDPE into flakes at an environment of 150-200°C.

[0046] In this step, preferably, HDPE is melted into sheets with a corrugated cross-section at an environment of 150-200°C to increase the specific surface area.

[0047] Step 202: Add pure water to the magnetic powder and mix. The ratio of magnetic powder to water is between 20:1 and 2000:1 to obtain a mixture of magnetic powder and water.

[0048] In this step, adding a small amount of water can make the magnetic powder distribute evenly, thus allowing the magnetic powder to be evenly spread to the bottom of the mold.

[0049] Step 203: Place the sheet HDPE obtained from melting in step 201 into the mixture obtained in step 202, and reheat to above 180°C to make the magnetic powder evenly adhere to the surface of the sheet HDPE. After maintaining this temperature for 2-5 minutes, cool and remove the mixture to obtain the core.

[0050] In this step, heating HDPE to above 180°C on the surface of the mixture causes water to evaporate and HDPE to enter a molten state. Due to its high viscosity in the molten state, the magnetic powder adheres to its surface. Preferably, after placing the sheet HDPE into the mixture, a pressure of 1500–4000 Pa can be applied while heating, which allows the magnetic powder to adhere better to the HDPE surface and forms a magnetic powder film on the outermost layer of HDPE.

[0051] Specifically, in order to uniformly coat the surface of the sheet HDPE with the magnetic powder, after the HDPE is melted into sheets and placed into the mixture, the lower surface of the sheet HDPE can be uniformly coated with the magnetic powder. The mixture can be heated to above 180°C, maintained for 2-5 minutes, cooled (for example, cooled to about 100°C), and removed. The sheet HDPE can then be turned over, melted into sheets again, and placed into the mixture to coat the other surface of the sheet HDPE with the magnetic powder. The mixture can then be heated to above 180°C again, maintained for 2-5 minutes, cooled, and removed.

[0052] Step 204: Wrap the filter cotton of claim 3 around the carrier prepared in step 203.

[0053] Preferably, in this step, heating can be used to accelerate the winding efficiency.

[0054] By coating the core surface with a fiber membrane, the adhesion of microorganisms can be improved, and a hypoxic environment can be better created for denitrifying bacteria inside the fiber membrane. This results in a biofilm structure with nitrifying bacteria as the main component outside the fiber membrane and denitrifying bacteria as the main component inside the fiber membrane, thus better achieving the goal of simultaneous nitrification and denitrification.

[0055] Step 205: Place the wound carrier again in a magnetic field environment of 1-3T or higher, apply vibration and hold for more than 10 seconds to complete the carrier preparation.

[0056] In this step, by placing the wound core in a magnetic field environment, the magnetic powder that was demagnetized during the preparation of the magnetic powder can be remagnetized, thereby improving the distribution quality of the magnetic powder in the core and ensuring that the magnetic field distribution is as uniform and the magnetic field direction is as consistent as possible.

[0057] The present application will be described in detail below through specific embodiments.

[0058] Example 1

[0059] Two sets of simultaneous nitrification and denitrification carriers of the same shape and size were prepared as the experimental group and the control group, respectively.

[0060] The experimental group used a magnetic synchronous nitrification-denitrification carrier, which included a core made of HDPE and specific iron oxide magnetic powder, and filter cotton covering the surface of the core. The core consisted of an inner core formed of HDPE and a magnetic powder film formed by iron oxide magnetic powder adhering to the surface of the inner core.

[0061] The specific iron oxide magnetic powder is prepared through the following steps:

[0062] (1) Place the iron oxide raw material into a container and then place it in a magnetic field environment of 0.5 to 1T to remove impurities by vibration sieve;

[0063] (2) Add pure water to the vibrated iron oxide, stir thoroughly and heat to 350-600°C, and maintain for at least 10 minutes to obtain heated iron oxide;

[0064] (3) After heating, the iron oxide is dried and taken out, ground and passed through 200-mesh and 500-mesh sieves. The iron oxide powder between 200-mesh and 500-mesh is collected to obtain the specific iron oxide.

[0065] Furthermore, the overall density of the filter cotton used is 0.96–0.98 g / cm³. 3 The thickness of the fabric is 2 to 8 mm.

[0066] The specific preparation method of the simultaneous nitrification and denitrification carrier in the experimental group includes the following steps:

[0067] S1, melting HDPE into sheets with a corrugated cross-section at 150-200℃;

[0068] S2, pure water is added dropwise to the specific magnetite powder and mixed, wherein the ratio of specific magnetite powder to water is 20:1 to 2000:1, to obtain a mixture of specific magnetite powder and water;

[0069] S3, molten sheet HDPE is placed into the mixture, so that the lower surface of the molten sheet HDPE is evenly coated with special magnetite powder. It is heated to above 180°C and maintained for 2-5 minutes, then cooled to about 100°C and removed. It is then turned over and melted into sheet form again and placed into the mixture, so that the other surface of the sheet HDPE is also evenly coated with special magnetite powder. It is heated to above 180°C again and maintained for 2-5 minutes, then cooled and removed, to obtain the core.

[0070] S4, the fiber membrane is wound around the core;

[0071] S5. The wound core is placed in a 1T magnetic field environment, and vibration is applied while maintaining the vibration for more than 10 seconds to complete the carrier preparation. The carrier prepared in the experimental group is as follows. Figure 1 As shown.

[0072] The control group used a non-magnetic simultaneous nitrification-denitrification carrier, comprising a core made of HDPE and filter cotton coating the surface of the core. The overall density of the filter cotton used was 0.96–0.98 g / cm³. 3 The thickness of the fabric is 2 to 8 mm.

[0073] The specific preparation method of the nitrification-denitrification carrier in the control group includes the following steps:

[0074] S1, melt HDPE into sheets at 150-200℃, and remove it after cooling;

[0075] S2, the fiber membrane is wound around the core;

[0076] S3. Vibrate the wound core and hold it for more than 10 seconds to complete the preparation of the synchronous nitrification and denitrification carrier in the control group.

[0077] With the influent ammonia nitrogen (NH4) +With the increase in ammonia nitrogen (ANO3) concentration, the dissolved oxygen (DO) in the reactor rose again to 1.5 mg / L. Comparison showed that the ammonia nitrogen removal efficiency of the experimental group was not affected, with the effluent ammonia nitrogen concentration dropping below 2 mg / L (mostly less than 1 mg / L). In contrast, the control group fluctuated with changes in influent and DO, generally remaining below 10 mg / L. Previous experiments revealed that as DO decreased, the ammonia oxidation rate in the control group decreased, while the experimental group was not affected by the decrease in DO; in fact, even after shortening the hydraulic retention time, the effluent ammonia nitrogen concentration remained stable. During the past month of operation, with the increase in influent ammonia nitrogen concentration and DO rising again to 1.5 mg / L, the simultaneous nitrification and denitrification of the reactor were not affected; instead, they increased to 60%, significantly higher than the control group.

[0078] After obtaining two sets of carriers, both sets of carriers were inoculated with the same batch of activated sludge of the same concentration, with a suspended sludge concentration of 3000 mg / L. The operational results were as follows. Figure 2-4 As shown. The reaction process is divided into two stages. The first stage is the trial operation stage, which lasts from day 1 to day 34. The second stage is the formal operation stage, in which the reactor uses the second batch of carrier and operates from day 35 to day 110. Similar to the first stage, both groups are inoculated with the same batch of sludge of the same concentration, and the suspended sludge concentration is also 3000 mg / L.

[0079] Depend on Figure 2-4 It can be seen that both the experimental and control groups showed significant COD removal effects, with effluent COD consistently maintained below 40 mg / L, and the experimental group's effluent COD consistently maintained below 30 mg / L. However, the effluent nitrate concentration (i.e., NO3-N concentration) of the experimental group was significantly lower than that of the control group. This indicates that under the same influent conditions, the experimental group can effectively remove more nitrate. In the initial stage of the second phase of reactor operation, data showed that dissolved oxygen (DO) could affect anaerobic digestion and efficiency to some extent. However, even when DO decreased to 1 mg / L, the experimental group could still maintain an effluent ammonia nitrogen concentration (NH4+) even after shortening the HRT (Hydraulic Retention Time) to 3 hours. +The ammonia nitrogen concentration in the influent was less than 5 mg / L, and the total nitrogen concentration in the effluent was less than 12 mg / L. As the influent ammonia nitrogen concentration increased, the dissolved oxygen (DO) in the reactor rose again to 1.5 mg / L. As seen in the control group, the ammonia nitrogen removal efficiency was not affected, with the effluent ammonia nitrogen concentration dropping below 2 mg / L (mostly less than 1 mg / L). In contrast, the control group fluctuated with changes in influent and DO, generally remaining below 10 mg / L. Previous experiments showed that as DO decreased, the ammonia oxidation rate in the control group decreased, while the ammonia oxidation rate in the experimental group was not affected by the decrease in DO. In fact, even after shortening the hydraulic retention time, the effluent ammonia nitrogen concentration remained stable. During the past month of operation, as the influent ammonia nitrogen concentration increased, the DO rose again to 1.5 mg / L. It was found that the simultaneous nitrification and denitrification in the reactor were not affected; instead, they increased to 60%, significantly higher than the control group. Compared to the control group, the ammonia nitrogen removal load of the experimental group was significantly higher, indicating that the magnetic carrier can enable microorganisms to achieve better ammonia oxidation efficiency. At the same time, compared to the control group, the DO concentration of the experimental group has a wider allowable adjustment range, making it easier to control the operating conditions.

[0080] The beneficial effects of this invention are as follows: (1) By using magnetic powder to form a unique magnetic field distribution on the surface of the core, and coating the core surface with a fiber membrane, the adhesion of microorganisms is improved, and they are also stimulated and affected by the magnetic field, which improves the activity of denitrifying bacteria, and forms a biofilm structure dominated by nitrifying bacteria on the outside and denitrifying bacteria on the inside, and achieves synchronous nitrification and denitrification under the stimulation of the magnetic field. (2) Pretreatment allows the iron oxide particles to be more evenly distributed on the HDPE surface, and grinding also allows the particles to obtain a higher magnetic field strength with a very small amount of addition. Placing the carrier twice in a strong magnetic field environment can obtain a better magnetic field distribution, effectively improving the stimulation of the carrier on nitrifying and denitrifying bacteria. (3) Since the carrier is a sheet structure with an additional fiber membrane on the outside, it can more effectively form nitrification and denitrification zones on the carrier surface, making the two more balanced and more effectively utilizing the carbon source in the water to achieve synchronous nitrification and denitrification. At the same time, since the density of the carrier in this invention is 0.98 g / cm³, 3The carrier can float well in the reactor and move with the aeration, making better contact with pollutants in the water and achieving efficient treatment of nitrogen pollutants. (4) The materials for preparing the carrier are simple, consisting only of specific iron tetroxide and HDPE, and the raw materials are easy to obtain. (5) The allowable range of dissolved oxygen (DO) concentration is very large. Because the carrier will form a thick biofilm structure, the magnetic core will promote the growth of internal denitrifying bacteria. Even if the dissolved oxygen in the external environment reaches more than 2 mg / L, the internal concentration can still be maintained within 0.5 mg / L, maintaining and ensuring a relatively stable denitrification environment. Therefore, both intermittent aeration and continuous aeration can meet the operating conditions of simultaneous nitrification and denitrification, ensuring the stable progress of the nitrification and denitrification process and making it easier to control the operating conditions.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A magnetic synchronous nitrification-denitrification carrier, characterized in that, include: The core is prepared from sheet-like HDPE and magnetic powder; the sheet-like HDPE and the magnetic powder are in the following proportions by weight: 1-10 parts magnetic powder, 90-98 parts HDPE; the core includes an inner core and a magnetic powder film; the inner core is formed of HDPE, and the magnetic powder film is formed of magnetic powder adhered to the surface of the inner core; the magnetic powder is specific magnetite; the specific magnetite has a purity of over 98% for magnetite with an inverse spinel structure; the specific magnetite is prepared by the following steps: Step 101: Place the iron oxide raw material into a container and then place it in a magnetic field environment of 0.5 to 1T to remove impurities by vibration sieve. Step 102: Add pure water to the vibrated iron oxide, stir thoroughly, heat to 350-600°C, and maintain for at least 10 minutes to obtain heated iron oxide. Step 103: After drying the heated iron oxide, take it out, grind it, and pass it through 200-mesh and 500-mesh sieves. Collect the iron oxide powder between 200-mesh and 500-mesh to obtain the specific iron oxide. A fiber membrane is used to cover the surface of the core.

2. The magnetic synchronous nitrification-denitrification carrier according to claim 1, characterized in that, The fiber membrane is filter cotton, polyurethane sheet, or honeycomb polypropylene.

3. The magnetic synchronous nitrification-denitrification carrier according to claim 2, characterized in that, The overall density of the filter cotton is between 0.96 and 0.98 t / m³. 3 The thickness of the fabric is 2 to 8 mm.

4. A method for preparing a magnetic synchronous nitrification-denitrification support according to any one of claims 1 to 3, characterized in that, Includes the following steps: Step 201: Melt HDPE into sheets at 150-200°C; Step 202: Add pure water to the magnetic powder and mix. The ratio of magnetic powder to water is between 20:1 and 2000:1 to obtain a mixture of magnetic powder and water. Step 203: Place the melted sheet HDPE into the mixture, heat to above 180°C, so that the magnetic powder is evenly adhered to the surface of the sheet HDPE, maintain for 2-5 minutes, cool and remove to obtain the core; Step 204: Wrap the fiber membrane around the core; Step 205: Place the wound core in a magnetic field environment of 1T or higher, apply vibration and hold for more than 10 seconds to complete the carrier preparation.

5. The method according to claim 4, characterized in that, Step 201 also includes: melting HDPE into sheets with a corrugated cross section at an environment of 150-200°C.

6. The method according to claim 4, characterized in that, Step 203 further includes: placing the melted sheet HDPE into the mixture, heating it to 180°C under a pressure of 1500-4000 Pa, maintaining it for 2-5 minutes, cooling it, and removing it to obtain the core.

7. The method according to claim 4, characterized in that, Step 204 further includes: winding the fiber membrane onto the core under heating conditions.

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