Preparation method and application of embedding particles for enriching anaerobic ammonia oxidation bacteria in situ

Abstract

The application discloses a treatment, preparation and application method of anaerobic ammonia oxidation bacteria embedding particles, and the embedding particle structure sequentially comprises a sulfur-iron catalytic layer of anaerobic ammonia oxidation bacteria, a biochar layer and an adsorption layer from inside to outside. The sulfur-iron catalytic layer comprises anaerobic ammonia oxidation bacterial strains and sulfur-iron powder; the biochar layer comprises volcanic stones and biochar; and the adsorption layer comprises sodium alginate, polyvinyl alcohol and modified bentonite, which are uniformly mixed in a mass ratio of 0.5-2.3:4-9:3-5, and the adsorption layer gel is formed in a constant-temperature water bath at 80-90 DEG C. The embedding particle has a three-layer structure, the adsorption layer gel exchanges ions or organic molecules with the external environment, provides nitrogen oxides for the sulfur-iron catalytic layer, avoids the stress effect of oxygen on the anaerobic ammonia oxidation bacteria, and maintains a stable internal environment of the embedding particle.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water treatment, and particularly relates to a preparation method and application of an embedding particle for in-situ enrichment of anammox bacteria. BACKGROUND

[0002] Anammox bacteria is a kind of facultative anaerobic bacteria, which can survive in an environment with a dissolved oxygen concentration of 0.1-8.0 mg / L. Generally, the anammox bacteria utilizes carbon dioxide and part of organic acids for nutritional metabolism, uses ammonia nitrogen and nitrite nitrogen as reaction substrates, and generates nitrogen gas through an oxidation-reduction reaction, without generating greenhouse gas nitrous oxide. However, the anammox bacteria grows slowly, and has a high requirement for the environment for enrichment culture. In addition, organic carbon in sewage or the environment can promote the growth of denitrifying bacteria, and the competitive inhibition effect of the denitrifying bacteria makes the nitrite nitrogen be reduced by the denitrifying bacteria, and releases nitrous oxide as a reaction byproduct.

[0003] It is difficult to avoid the competition of anammox bacteria and heterotrophic denitrifying bacteria for the reaction substrate nitrite nitrogen by using common physical and chemical methods, not to mention promoting the growth and metabolism of the anammox bacteria. In addition, in the enrichment process of the anammox bacteria, although the anammox bacteria has a large dissolved oxygen niche, it is crucial to maintain the function and activity of the anammox bacteria to minimize the influence of dissolved oxygen on the anammox bacteria.

[0004] Traditional enrichment methods are usually realized in laboratory reactors through inoculation, that is, by maintaining a low dissolved oxygen concentration (generally 0.1-0.5 mg / L), inhibiting the activity of nitrifying bacteria, and reducing the conversion of nitrite nitrogen to nitrate nitrogen, so that the inoculated anammox bacteria can obtain the required nitrite nitrogen for growth, and ensure that the anammox bacteria can grow and enrich in the reactor. In practical applications, the low-dissolved-oxygen operation process has complex requirements, high cost, and reduces the metabolic activity of microorganisms in other biological denitrification processes, which is not conducive to long-term stable operation.

[0005] Therefore, how to stably and long-term enrich and culture the anammox bacteria is the key to realizing the anammox process. SUMMARY

[0006] For the above problems, the embedding particle of the application creatively uses the mixture of iron sulfide sintered solid and enriched anaerobic ammonia oxidation bacteria genus, so that the iron sulfide ion promotes the growth metabolism of the anaerobic ammonia oxidation bacteria genus, and further improves the environmental adaptability of the anaerobic ammonia oxidation bacteria genus; the biochar can strengthen the growth activity of the environmental geobacillus genus and competitively inhibit the metabolic effect of the denitrifying strain; when the ammonia nitrogen is lacking in the environment, the geobacillus genus can also provide ammonia nitrogen for the anaerobic ammonia oxidation bacteria genus; the biochar has a high specific surface area, can strengthen the anion exchange between the iron sulfide catalytic layer and the outside world, and at the same time reduce the interference of metal cations and acid radicals in the environment on the iron sulfide catalytic layer, so as to provide a suitable environmental carrier for the growth of the anaerobic ammonia oxidation bacteria genus; the adsorption layer exchanges the anaerobic ammonia oxidation reaction substrates and products with the outside environment, provides nitrite nitrogen for the iron sulfide catalytic layer, avoids the direct poisoning of oxygen on the anaerobic ammonia oxidation bacteria genus, and maintains the stable internal environment of the embedding particle; the bentonite and sodium alginate in the composition can improve the mechanical properties of the embedding particle, reduce the damage of external force to the structure of the embedding particle, and play a good barrier protection effect.

[0007] 1. The first content of the application provides an embedding particle structure for in-situ enrichment of anaerobic ammonia oxidation bacteria. The multi-layer structure of the embedding particle comprises, from inside to outside, a sulfur-iron catalytic layer containing anaerobic ammonia oxidation bacteria, a biochar layer and an adsorption layer; the sulfur-iron catalytic layer comprises anaerobic ammonia oxidation bacteria and sulfur-iron powder; the biochar layer comprises volcanic rock and biochar; and the adsorption layer comprises sodium alginate, polyvinyl alcohol and modified bentonite. The embedding particle has a three-layer structure, which at least meets one of the following characteristics:

[0008] (1) The sulfur-iron catalytic layer of the anaerobic ammonia oxidation bacteria comprises anaerobic ammonia oxidation bacteria, sulfur-iron ore and volcanic rock sintered powder; the biochar layer comprises one or more of bamboo, reed and giant reed; and the adsorption layer comprises modified bentonite, sodium alginate and polyvinyl alcohol. Among them, the polymerization agent can be one of polyvinyl alcohol, stearic acid, sodium dodecyl sulfonate and cetyltrimethylammonium bromide.

[0009] (2) The sulfur-iron catalytic layer mixed solution of the anaerobic ammonia oxidation bacteria is prepared by mixing the anaerobic ammonia oxidation bacteria solution, the sulfur-iron ore and the volcanic rock sintered powder, and the sterile water in a volume ratio of 1:3:9.

[0010] (3) The biochar is one or more of bamboo, giant reed and reed, is placed in a muffle furnace for high-temperature treatment at 300-400 DEG C, is then soaked in 1-2 mol hydrochloric acid for 1-2 hours, and is finally prepared into 1-3 cm granular materials.

[0011] (4) The embedding particle precursor is composed of a sulfur-iron catalytic layer containing anaerobic ammonia oxidation bacteria and a biochar layer, i.e. the biochar is placed in the sulfur-iron catalytic layer mixed solution of anaerobic ammonia oxidation bacteria strains, and the embedding particle precursor is prepared after 7-14 days of biofilm formation treatment.

[0012] (5) The embedding particle includes an adsorption layer gel and an embedding particle precursor, wherein the modified bentonite, polyvinyl alcohol and sodium alginate are prepared into the adsorption layer gel at a mass ratio of 1-3:4-9:1.5-2.3; and the embedding particle includes a sulfur-iron catalytic layer containing anaerobic ammonia oxidation bacteria and a biochar layer.

[0013] 2. The second content of the present application provides a preparation method of in-situ enrichment of anaerobic ammonia oxidation bacteria embedding particles, and the steps are as follows:

[0014] (1) First, the sludge containing anaerobic ammonia oxidation bacteria strains is cultured under anaerobic conditions; the culture solution is replaced with an equal volume every 4 hours, the ammonia nitrogen concentration in the culture solution is 13 mg / L, and the nitrite nitrogen concentration is 10 mg / L, to obtain a bacterial solution containing anaerobic ammonia oxidation bacteria;

[0015] (2) Secondly, the powder of sulfur-iron ore and volcanic rock sintered, i.e. the sulfur-iron ore and volcanic rock are treated at 600℃ for 4.5-5 hours, and then sintered in a muffle furnace at a volume ratio of 1:1 to prepare the powder; the bacterial solution containing anaerobic ammonia oxidation bacteria strains, the sulfur-iron ore and volcanic rock powder and sterile water are mixed at a volume ratio of 1:3:9 to prepare a sulfur-iron catalytic layer mixed solution containing anaerobic ammonia oxidation bacteria strains;

[0016] (3) Further, one or more of bamboo, bamboo and reed is placed in a muffle furnace and treated at a high temperature of 300-400℃, and then soaked in 1-2 mol of hydrochloric acid for 1-2 hours to prepare biochar; the biochar is prepared into a particle material with a size of 1-3 cm, and then placed in the sulfur-iron catalytic layer mixed solution containing anaerobic ammonia oxidation bacteria strains, and the biofilm is formed under anaerobic conditions for 7-14 days to prepare an embedding particle precursor composed of a sulfur-iron catalytic layer of anaerobic ammonia oxidation bacteria and a biochar layer;

[0017] (4) Finally, the acid-modified bentonite is prepared under the following conditions: pH=5.2-6.5, rotation speed 200-220 rpm, stirring time 50-70 minutes, and bentonite addition amount 15-18 g / L. The acid-modified bentonite removes metal cations, and then the modified bentonite is added into sodium alginate and polyvinyl alcohol, and the polyvinyl alcohol can be replaced by a polymerization agent such as stearic acid, sodium dodecyl sulfonate and cetyltrimethylammonium bromide. The mass ratio of the modified bentonite, polyvinyl alcohol and sodium alginate is 1-3:4-9:1.5-2.3, and the three are fully mixed at a constant temperature of 80-90℃ in a water bath to form an adsorption layer gel.

[0018] (5) The embedding particle precursor is mixed with the adsorption layer gel according to steps (1), (2), (3) and (4) of the second purpose of the above invention content, so as to prepare the embedding particle containing the anaerobic ammonia oxidation bacteria.

[0019] 3. The third content of the present application is to provide a preparation method of embedding particles of anaerobic ammonia oxidation bacteria in situ, and to apply it to the water treatment process. That is, the sintered sulfur-iron powder is mixed with the bacteria solution containing anaerobic ammonia oxidation bacteria to prepare a sulfur-iron catalytic layer containing the bacteria strain; and then the embedding particle precursor is prepared with the biochar, which includes the sulfur-iron catalytic layer of anaerobic ammonia oxidation bacteria and the biochar layer; the embedding particle precursor is added to the adsorption layer gel to be fully wrapped to form the embedding particle with anaerobic ammonia oxidation bacteria.

[0020] The embedding particle of the present application has simple ratio composition and is easy to use, and can be directly filled in the surface layer of soil as a substrate ratio scheme, and can be used in various biofilm reactors in a biofilm mode, or can be filled in constructed wetlands and rainwater facilities as a substrate ratio scheme; the prepared embedding particle can also be pre-embedded in water treatment devices or the surface layer of soil with different backgrounds to promote the growth and metabolism of anaerobic ammonia oxidation bacteria, to strengthen the removal effect of nitrogen oxides, and to reduce the release of greenhouse gas nitrous oxide in the biological denitrification process.

[0021] It should be noted that the organic carbon in sewage or the environment can promote the growth of denitrifying bacteria, reduce nitrite nitrogen to nitrogen gas, and thus competitively inhibit the growth of anaerobic ammonia oxidation bacteria, and release nitrous oxide as a byproduct.

[0022] To this end, the present application can effectively inhibit the anaerobic heterotrophic denitrification process through the competitive advantage of Geobacter and the process of reducing heterologous nitrate nitrogen to ammonia nitrogen. The embedding particle treatment method of the present application is simple and easy to operate, and can realize the sulfur autotrophic denitrification reaction and the redox reaction of divalent iron and nitrite nitrogen under the set conditions, and further competitively inhibit the growth and metabolism of anaerobic heterotrophic denitrifying bacteria, and can be used for the complete oxidation and reduction of different forms of nitrogen oxides.

[0023] The present application has the following advantages and effects:

[0024] 1. The mixture of sulfur-iron powder and anaerobic ammonia oxidation bacteria can promote the growth and metabolism of anaerobic ammonia oxidation bacteria, and further improve the adaptability of anaerobic ammonia oxidation bacteria to the environment;

[0025] 2. The biochar promotes the growth and metabolism of Geobacter and inhibits the growth of denitrifying bacteria; and provides ammonia nitrogen for anaerobic ammonia oxidation bacteria when there is a lack of ammonia nitrogen. In addition, the high specific surface area of the biochar can strengthen the anion exchange between the sulfur-iron catalytic layer and the outside world, and at the same time reduce the interference of metal cations and acid radicals in the environment on the sulfur-iron catalytic layer, to provide a suitable environmental carrier for the growth of anaerobic ammonia oxidation bacteria.

[0026] 3. The adsorption layer gel exchanges substrates and products with the external environment, provides nitrogen oxides for the sulfur-iron catalytic layer, avoids the stress of oxygen on the anammox bacteria, and maintains a stable internal environment of the embedded particles; the bentonite and sodium alginate in the composition can improve the mechanical properties of the embedded particles, reduce the damage of external force to the structure of the embedded particles, and play a good barrier protection role;

[0027] 4. The three-layer structure of the embedded particles can be applied to the surface layer of soil to strengthen the anammox reaction; or embedded in various biological denitrification reactors;

[0028] 5. The method can enrich anammox bacteria in situ, promote the growth and metabolism of Geobacter by biochar, use the competitive advantage to make nitrogen oxides less reduced by denitrification; at the same time, Geobacter reduces nitrogen oxides to ammonia nitrogen and further uses it as an anammox reaction substrate to reduce it to nitrogen. In this process, the emission of nitrous oxide in the denitrification process is reduced, and nitrogen oxides are efficiently reduced to nitrogen. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 A structure diagram of an embedded particle for enriching anammox bacteria in situ;

[0030] 1. Sulfur-iron catalytic layer; 2. Biochar layer; 3. Adsorption layer. DETAILED DESCRIPTION

[0031] The embodiments of the present application will be described in detail below with reference to the examples, but the present application is not limited to these examples. In the following examples, the test methods used are conventional methods unless otherwise specified; and the materials, reagents, etc. used are commercially available unless otherwise specified.

[0032] The technical method of an embedded particle for enriching anammox bacteria in situ will be described below through specific steps combined with the drawings. The examples provided are only illustrative of the implementation of the method in specific cases and do not encompass all examples. In addition, the examples provided are intended to provide a reference for the implementation, but not to limit the broader application of the present application.

[0033] Example 1

[0034] This example provides a specific preparation method, which includes the following steps:

[0035] 1. The sludge containing anammox bacterial strains is cultured under anaerobic conditions, and the reactor is supplemented with an equal volume of nutrient solution every 4 hours; wherein the ammonia nitrogen concentration is 13 mg / L, and the nitrite nitrogen concentration is 10 mg / L, to prepare a bacterial solution containing anammox bacteria;

[0036] 2. Pyrite and volcanic rock are sintered in a muffle furnace at 600℃ in a 1:1 volume ratio to produce powder; pyrite and volcanic rock powder containing anaerobic ammonia-oxidizing bacteria, along with sterile water, are mixed in a 1:3:9 volume ratio to prepare a pyrite-iron catalytic layer mixture containing anaerobic ammonia-oxidizing bacteria, i.e., the attached... Figure 1 The sulfur-iron catalyst layer 1 in the middle;

[0037] 3. Bamboo, reed, and rush are treated at 300℃ and then soaked in 1 mol hydrochloric acid for 1 hour to produce biochar. The biochar is then granulated into particles of 1–3 cm in size and placed in a mixture containing a sulfur-iron catalytic layer of anaerobic ammonia-oxidizing bacteria. Under anaerobic conditions, a biofilm is formed for 10 days to produce an embedded particle precursor consisting of a sulfur-iron catalytic layer of anaerobic ammonia-oxidizing bacteria and a biochar layer. Figure 1 The sulfur-iron catalyst layer 1 and biochar layer 2 are in the middle;

[0038] 4. The conditions for acid-modified bentonite were: pH = 5.2–6.5, stirring speed 220 rpm for 60 minutes, and bentonite addition amount 18 g / L. The mass ratio of modified bentonite, polyvinyl alcohol, and sodium alginate was 1.5:4.5:2, and the three were thoroughly mixed in an 85℃ water bath to form an adsorption layer gel.

[0039] 5. The pre-embedded particle is fully coated with the epidermal gel to form an embedded particle containing anaerobic ammonia-oxidizing bacteria, i.e., an epidermal gel containing anaerobic ammonia-oxidizing bacteria. Figure 1 It has a three-layer structure containing a sulfur-iron catalyst layer 1, a biochar layer 2, and an adsorption layer 3.

[0040] Example 2

[0041] This embodiment 2 provides a technical application solution, in which the method for preparing the encapsulated particles of anaerobic ammonia-oxidizing bacteria is the same as in embodiment 1:

[0042] 1. The surface subsurface flow constructed wetland has a tank height of 40cm, a substrate filling height of 30cm, and a gravel layer on the surface as a filter layer. A continuous flow influent method is used to simulate the treatment of domestic sewage, with influent ammonia nitrogen of 30mg / L, total chemical oxygen demand of 60mg / L, temperature set at 20℃~25℃, and hydraulic retention time of 24 hours.

[0043] 2. The prepared embedded particles are pre-embedded in a pool 10 cm away from the matrix surface;

[0044] 3. The artificial wetland device is continuously operated for 360 days, and the ammonia nitrogen and total nitrogen concentrations are monitored every 20 days. The removal rate of ammonia nitrogen increases from 36.7% to 67.8%, and the total nitrogen removal rate increases from 45.5% to 76.8%. Through 16S amplicon sequencing and metagenomic sequencing analysis, the abundance of Candidatus Brocadia and anaerobic ammonia oxidation clone bacteria varies in the range of 0.0629% to 0.183%. In addition, the relative abundance of Geobacter varies in the range of 0.441% to 0.754%, the relative abundance of Dessulfobrivo, Desulfobulbus varies in the range of 0.0233% to 0.0412% and 0.035% to 0.067% respectively, and the relative abundance of Thiobacillus varies in the range of 0.629% to 2.03%, which is higher than the common denitrifying bacteria Thauera 0.023% to 0.034%, Paraccous 0.017% to 0.011%, and Pseudomonas 0.0638% to 1.16%. That is, the sulfur bacteria and sulfur-reducing bacteria have a competitive advantage over heterotrophic denitrifying bacteria, and more nitrate nitrogen is reduced to ammonium nitrogen and nitrogen gas by sulfur bacteria and sulfur-reducing bacteria.

[0045] 4. In the third step of Case 2, the ammonium nitrogen and nitrite nitrogen generated by the sulfur bacteria and sulfur-reducing bacteria through catalytic heterotrophic reduction of nitrate nitrogen can be further used as a reaction substrate to be reduced to nitrogen gas by anaerobic ammonia oxidation bacteria.

[0046] Example 3

[0047] The present embodiment provides a specific preparation method, comprising the following steps:

[0048] 1. The sludge containing anaerobic ammonia oxidation bacteria is cultured under anaerobic conditions, and the reactor is supplemented and replaced with an equal volume of nutrient solution every 4 hours; wherein the ammonium nitrogen concentration is 13 mg / L, and the nitrite nitrogen concentration is 10 mg / L, to prepare a bacteria solution containing anaerobic ammonia oxidation bacteria;

[0049] 2. The pyrite and volcanic rock are sintered at 600°C to form a powder according to a volume ratio of 1:1 in a muffle furnace; the bacteria solution containing anaerobic ammonia oxidation bacteria, the pyrite and volcanic rock powder, and sterile water are mixed according to a volume ratio of 1:3:9 to prepare a sulfur-iron catalytic layer mixed solution containing anaerobic ammonia oxidation bacteria, i.e. the sulfur-iron catalytic layer 1 in the appendix Figure 1

[0050] ​3. Bamboo, Arundo donax and Phragmites australis are treated at 400℃, soaked in 1 mol hydrochloric acid for 2 hours to produce biochar; the biochar is made into 1-3 cm particles, and placed in a mixed solution containing anaerobic ammonia oxidation bacteria and a sulfur-iron catalytic layer, and the membrane is hung for 14 days under anaerobic conditions to produce a sulfur-iron catalytic layer and a biochar layer, i.e. a sulfur-iron catalytic layer 1 and a biochar layer 2 in the embedded particle precursor of the application. Figure 1

[0051] 4. Acid-modified bentonite is prepared under the following conditions: pH = 5.2-6.5, rotation speed 220 rpm, stirring time 60 min, and bentonite addition amount 18 g / L. The mass ratio of modified bentonite, stearic acid and sodium alginate is 3:7:2, and the three are fully mixed at 80℃ water bath to form an adsorption layer gel.

[0052] 5. The embedded particle precursor is fully wrapped with the adsorption layer gel to form an embedded particle containing anaerobic ammonia oxidation bacteria, i.e. a three-layer structure containing a sulfur-iron catalytic layer 1, a biochar layer 2 and an adsorption layer 3. Figure 1

[0053] 6. The embedded particle is applied to a surface subsurface constructed wetland, and the relative abundance of Thiobacillus is in the range of 2.56%-4.31%, the relative abundance of Desulfobulbus is in the range of 0.735%-1.12%, the relative abundance of Desulfovibrio is in the range of 0.623%-1.46%, the relative abundance of Geobacter is in the range of 1.16%-1.64%, and the relative abundance of Thauera, the main denitrifying bacteria, is in the range of 0.73%-1.47%, indicating that the sulfur autotrophic denitrification process is the main mechanism for nitrate nitrogen removal. After 90 days of long-term operation, it is found that the nitrate nitrogen removal rate is increased from 51.3% to 77.9% after the application of the embedded particle, while the total phosphorus removal efficiency is 41.2%-83.6% and the total chemical oxygen demand removal rate is 45.3%-74.6%.

[0054] Example 4

[0055] The embedded particle containing anaerobic ammonia oxidation bacteria is prepared according to the steps of Example 3, and is used to improve the water quality purification effect of Dinggang Lake in Shenzhen City, Guangdong Province. The main inflow of the lake is sewage plant effluent and rainwater. The embedded particle is used in the transition area between the inflow pipe and the lake, and the area is about 1-2 m 2 ​​The soil is replaced, and the soil is replaced to a depth of 7-15 cm, the embedded particles are filled to a height of about 1-3 cm, and the soil is backfilled to the original height; wherein the transition riparian zone comprises an above-water and underwater area. The ammonia nitrogen and total nitrogen concentrations of the lake are monitored for 180 consecutive days, and both can reach the national surface water class IV standard (GB3838-2002).

[0056] The technical features of the above embodiments can be combined in any manner. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described, but as long as the combinations of the technical features do not contradict, they should be considered as falling within the scope of the present disclosure.

[0057] The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for producing an immobilized particle for in-situ enrichment of Candidatus Brocadia, characterized by, It comprises the following steps: (1) The sludge containing anaerobic ammonia-oxidizing bacteria is cultured under anaerobic conditions, 13 mg / L ammonia nitrogen and 10 mg / L nitrite nitrogen are provided to obtain anaerobic ammonia-oxidizing bacteria liquid; pyrite and volcanic rock are mixed in a volume ratio of 1.1-1.3:1.1-1.3, sintered at 600°C for 4.5-5 hours to form a mixed powder, and the anaerobic ammonia-oxidizing bacteria liquid, the mixed powder and sterile water are mixed in a volume ratio of 0.9-1.1:3-3.2:8.9-9.2 to obtain a sulfur-iron catalytic layer mixed liquid of anaerobic ammonia-oxidizing bacteria; (2) One or more of bamboo, bamboo and reed are taken, treated at 300-400°C in a muffle furnace for 24-48 hours, then soaked in 1-2 mol hydrochloric acid for 1-2 hours to form biochar; the biochar is made into 1-3 cm size granular material, placed in the sulfur-iron catalytic layer mixed liquid of anaerobic ammonia-oxidizing bacteria, and treated under anaerobic conditions for 7-14 days to form a biochar layer and a sulfur-iron catalytic layer of anaerobic ammonia-oxidizing bacteria, which form a biochar layer and a sulfur-iron catalytic layer of anaerobic ammonia-oxidizing bacteria; (3) The acid-modified bentonite is removed from the metal cations, the specific surface area and the pore volume are increased, and then sodium alginate and polyvinyl alcohol are added, and polyvinyl alcohol is replaced by stearic acid, sodium dodecyl sulfonate and cetyltrimethylammonium bromide polymerization agent; the three are formed into an adsorption layer gel in a constant temperature water bath at 80-90°C; (4) The biochar layer and the sulfur-iron catalytic layer of anaerobic ammonia-oxidizing bacteria are added to the adsorption layer gel and fully wrapped to form a biochar layer and a sulfur-iron catalytic layer of anaerobic ammonia-oxidizing bacteria.

2. The preparation method of the embedded particle for in-situ enrichment of anaerobic ammonia-oxidizing bacteria according to claim 1, which satisfies at least one of the following characteristics: (1) The anaerobic ammonia-oxidizing bacteria are added in the form of anaerobic sludge bacteria clusters; (2) The sulfur-iron catalytic layer is composed of sintered pyrite and volcanic rock powder; (3) The biochar layer is acid-modified biochar; (4) The adsorption layer is acid-modified bentonite.

3. The preparation method of the embedded particle for in-situ enrichment of anaerobic ammonia-oxidizing bacteria according to claim 1, characterized in that: The mixed powder is pyrite and volcanic rock placed in a muffle furnace and sintered at 600°C for 4.5-5 hours in a volume ratio of 1.1-1.3:1.1-1.

3.

4. The method of claim 1, wherein the method is characterized by: The biochar is treated at 300-400°C for 24-48 hours and soaked in 1-2 mol hydrochloric acid for 1-2 hours to form.

5. The method of claim 1, wherein the method is characterized by: The acid-modified bentonite is prepared under the following conditions: pH=5.2-6.5, rotation speed 200-220 rpm, stirring time 50-70 min, and bentonite addition amount 15-18 g / L.

6. The method of claim 1, wherein the method is characterized by: The mass ratio of the acid-modified bentonite, polyvinyl alcohol and sodium alginate is 3-5:4-9:0.5-2.3, and the three are fully mixed in a water bath at 80-90°C to form an adsorption layer gel.

7. The method of claim 1, wherein the method is characterized by: The anaerobic ammonia oxidation strain is enriched by anaerobic culture; sludge containing the anaerobic ammonia oxidation strain is placed in a culture bottle, nitrogen is introduced to maintain an anaerobic environment, and a reaction solution containing 13 mg / L ammonia nitrogen and 10 mg / L nitrite nitrogen is added every 4 hours to obtain a precursor containing anaerobic ammonia oxidation strain embedded particles.

8. The method of claim 1, wherein the method is characterized by: The raw material of the biochar includes one or more of bamboo, bamboo or reed; the sulfur-iron catalytic layer includes anaerobic ammonia oxidation strains and sintered sulfur-iron powder.

9. A method of sewage treatment, characterised by: The embedded particles prepared by the preparation method in any one of claims 1-8 are used in the field of biological wastewater treatment by in-situ enrichment of anaerobic ammonia oxidation bacteria, and the effect of anaerobic ammonia oxidation denitrification reaction is strengthened.

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