Preparation method of a bio-selective porous iron-sulfur autotrophic denitrification filler

Abstract

The application discloses a kind of biological selective porous iron sulfur autotrophic denitrification filler preparation methods, comprising the following steps: pyrite and sulfur are respectively ground to-74 μm in sample preparation machine, then ball milling is carried out;After the pyrite powder after ball milling is carried out in 9K base medium aerobic biological activation, solid-liquid separation is carried out, and aerobic activated ore is obtained;After replacing fresh medium, sulfur is added, and nitrogen is used to chase air and carry out anaerobic biological activation, then solid-liquid separation is carried out, and anaerobic activated ore is obtained;After the obtained anaerobic activated ore is cleaned on surface using dilute hydrochloric acid, sodium bicarbonate, activated carbon is mixed, ball milling is carried out, balling is carried out, and low-temperature sintering is carried out, to obtain biological selective porous iron sulfur autotrophic denitrification filler.The biological selective porous iron sulfur autotrophic denitrification filler preparation method of the application has wide raw material sources and low cost, can selectively promote iron sulfur autotrophic microorganism adsorption growth, and can realize ideal efficiency of wastewater advanced treatment and denitrification and phosphorus removal.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, and in particular relates to a method for preparing a biological selective porous iron-sulfur autotrophic denitrification packing. Background Technology

[0002] With the improvement of wastewater treatment rates, sludge disposal rates, and emission standards, the energy consumption of wastewater treatment will further increase. Under the dual-carbon context, promoting the upgrading and transformation of equipment in key industries such as wastewater treatment, focusing on energy conservation, emission reduction, and ultra-low emissions, and developing energy-efficient wastewater treatment processes that balance efficient nitrogen / phosphorus removal with energy reduction, is an inevitable trend in the development of the wastewater treatment industry. This has significant environmental, ecological, and economic implications for promoting green and low-carbon development in the wastewater treatment industry and alleviating its carbon emission pressure.

[0003] Sulfur autotrophic denitrification is a process in which autotrophic sulfur bacteria utilize reduced sulfur (H2S, S2S) under anaerobic or hypoxic conditions. 2- S2O3 2- NO3 is used as an electron donor. 2- / NO2 - Denitrification, a technology that uses electron acceptors for nitrification, can achieve highly efficient nitrate nitrogen removal under non-organic carbon-dependent conditions. However, this process also has some drawbacks, such as the production of acids and sulfates, and the promotion of NO2 in water. - The accumulation of Fe. As is well known, the biological oxidation of iron often requires the consumption of protons, and the iron autotrophic denitrification process is based on Fe... 0 / Fe 2+ It acts as an electron donor. Combining the autotrophic denitrification processes of iron and sulfur to form an iron-sulfur autotrophic denitrification process not only consumes the acid produced in the sulfur autotrophic process but also promotes the synergistic transformation of iron and sulfur forms and couples the phosphorus transformation process, which is beneficial for the simultaneous removal of nitrogen and phosphorus. Furthermore, it can further improve nitrogen removal efficiency, achieving coordinated removal of carbon, nitrogen, and phosphorus under conditions of low carbon-to-nitrogen ratio, low aeration volume, and no external carbon source, while avoiding SO42-. 2- Excessive accumulation.

[0004] Currently, there is a lack of reasonable methods for preparing bioselective porous iron-sulfur autotrophic denitrification packing materials, which to some extent restricts the integration of iron and sulfur autotrophic denitrification processes. Summary of the Invention

[0005] Based on the technical problems mentioned in the background art, the purpose of this invention is to provide a method for preparing biologically selective porous iron-sulfur autotrophic denitrification packing, so as to selectively promote the biofilm formation process of iron-sulfur autotrophic microorganisms, accelerate the iron-sulfur autotrophic start-up process, and improve the nitrogen and phosphorus removal efficiency.

[0006] This invention proposes a method for preparing a biologically selective porous iron-sulfur autotrophic denitrification packing material, comprising the following steps:

[0007] (1) The iron-sulfur minerals and sulfur were ground to -74 μm in a sample preparation machine, and then the iron-sulfur minerals were ball-milled to activate the surface to obtain surface-activated minerals;

[0008] (2) The surface-activated minerals obtained in step (1) were placed in 9K basal medium with an initial pH of 1.8 and inoculated with acidophilic iron-sulfur oxidizing microorganisms at a concentration of 1×10⁻⁶. 8 / mL, stirring speed 170 rpm, after activation, solid-liquid separation was performed to obtain aerobic activated ore;

[0009] (3) Add the aerobic activated mineral obtained in step (2) to fresh 9K basic culture medium, inoculate the bacterial mud separated from the filtrate in step (2), add elemental sulfur, adjust the initial pH to 1.8, use nitrogen to drive out the air in the reactor and seal it, stir at 170 rpm, and after activation, separate the solid and liquid to obtain anaerobic activated mineral.

[0010] (4) The anaerobic activated mineral obtained in step (3) is washed in 1 mol / L HCl solution and sterilized by ultraviolet light for 30 min. Then it is mixed with sodium bicarbonate and activated carbon in a sample preparation machine, followed by ball milling, pelletizing and sintering to obtain biological selective iron-sulfur autotrophic denitrification packing.

[0011] Furthermore, the iron-sulfur minerals mentioned in step (1) include at least one of pyrite, makinoite, pyrrhotite and marcasite.

[0012] Furthermore, the ball milling conditions described in step (1) are: ball-to-material ratio of 1.5 to 3:1, rotation speed of 200 to 400 rpm / min, and ball milling time of 0.5 to 3 h.

[0013] Furthermore, the activation conditions described in step (2) are: slurry concentration of 5~30 g / L, activation reaction temperature of 55~80°C, and activation reaction time of 12~144 h.

[0014] Furthermore, the acidophilic iron-sulfur oxidizing microorganisms mentioned in step (2) mainly include Bacillus cycloalisate (Sendai). 仙台 Alicyclobacillus ), Wanzao acidophilus ( 万座酸浆菌 Metallsulfuron-methyl ( 金属硫化叶菌 ) and diligent metallococci ( 嗜热栖热硫化叶菌 At least two of them.

[0015] Furthermore, the activation conditions described in step (3) are: slurry concentration of 5~30 g / L, elemental sulfur addition of 10~50 g / L, activation reaction temperature of 55~80°C, and activation reaction time of 48~168 h.

[0016] Furthermore, in step (3), the anaerobic activated ore is mixed with sodium bicarbonate and activated carbon at a mass ratio of 10~50:2~5:1, and the sintering temperature of the mixture is 70~110°C.

[0017] The surface-activated slag of this invention is produced by ball milling iron-sulfur minerals, which mechanically activates and oxidizes the surface lattice of the iron-sulfur minerals. This process can create lattice defects on the surface of the iron-sulfur minerals, reduce the surface chemical energy, and facilitate subsequent biological activation processes.

[0018] The aerobic activated residue of this invention is obtained by aerobic leaching activation of surface activated residue mediated by acidophilic iron-sulfur microorganisms. During the aerobic activation process, Fe is easily dissolved from the S defects in the surface activated residue and oxidized to Fe by the acidophilic iron-sulfur microorganisms. 3+ And it is bonded to the cell surface. Acidophilic iron-sulfur microorganisms use bonded Fe... 3+ Further indirect oxidation of the iron-sulfur mineral components on the surface leads to erosion pits and defects, as well as Fe... 2+ The dissolution process can form a cycle mediated by acidophilic iron-sulfur microorganisms, continuously activating and eroding the surface of iron-sulfur minerals, resulting in a hydrophobic and porous surface that is more easily adsorbed by microorganisms and reacts with the iron-sulfur minerals. This process also causes the accumulation of elemental sulfur and secondary iron-vanadium compounds on the surface, leading to partial surface passivation.

[0019] The anaerobic activated residue of this invention is obtained from aerobic leaching residue through anaerobic leaching activation mediated by acidophilic iron-sulfur microorganisms. During the anaerobic activation process, there is a dynamic equilibrium between the dissolution of iron and vanadium compounds accumulated on the surface of the aerobic leaching residue. The acidophilic iron-sulfur microorganisms can use the elemental sulfur accumulated and added on the surface of the aerobic leaching residue as electron donors to reduce the Fe released from the dissolution of iron and vanadium compounds. 3+ This causes the dissolution equilibrium of iron and vanadium compounds to shift to the right, continuously promoting their dissolution. This process can effectively remove passivating components from the surface of aerobic activated slag.

[0020] The anaerobic leaching residue can be washed in 1 mol / L HCl solution and sterilized with ultraviolet light for 30 min to remove the surface biofilm. After sintering with activated carbon and sodium bicarbonate, the bioselective porous packing of the present invention can be obtained.

[0021] During ball milling, the ball-to-material ratio, rotation speed, and milling time need to be controlled. The ball-to-material ratio should be 1.5~3:1, the rotation speed should be 200~400 rpm / min, and the milling time should be 0.5~3 h to ensure that the micro-region structure of iron-sulfur minerals can be activated and destroyed, thereby improving the efficiency of subsequent activation reactions.

[0022] During aerobic activation, the pulp concentration, activation temperature, and activation time need to be controlled. The pulp concentration should be controlled at 5-30 g / L, the activation temperature at 55-80°C, and the activation time at 12-144 h to ensure that acidophilic iron-sulfur microorganisms can fully erode and leach from the surface of iron-sulfur minerals under aerobic conditions, producing a loose and porous structure without excessive accumulation of iron-vanadium compounds and elemental sulfur.

[0023] During anaerobic activation, the pulp concentration, activation temperature, and activation time need to be controlled. The pulp concentration should be 5-30 g / L, the amount of elemental sulfur added should be 10-50 g / L, the activation temperature should be 55-80°C, and the activation time should be 48-168 h to ensure that the acidophilic iron-sulfur microorganisms can fully decompose the accumulated elemental sulfur and iron-vanadium passivation layer under anaerobic conditions.

[0024] When anaerobic activated minerals are mixed with sodium bicarbonate and activated carbon in a sample preparation machine, the mass ratio should be 10~50:2~5:1 to ensure that the packing has iron-sulfur autotrophic denitrification substrate, sufficient pH buffering capacity and high electron transfer efficiency.

[0025] The beneficial effects of this method are as follows:

[0026] By controlling the appropriate ball-to-material ratio, rotation speed, and ball milling time, the surface of the iron-sulfur minerals is fully mechanically activated to generate lattice defects, thereby improving the leaching activation performance of the iron-sulfur minerals. By controlling the appropriate solid slurry concentration, activation reaction temperature, and activation reaction time, the iron-sulfur minerals are fully activated to obtain a loose and porous surface structure. By controlling the mass ratio of anaerobic activated minerals to sodium bicarbonate and activated carbon, the packing material is ensured to have iron-sulfur autotrophic denitrification substrate, sufficient pH buffering capacity, and high electron transfer efficiency.

[0027] In summary, this invention can activate iron-sulfur minerals, forming a loose, porous structure on the mineral surface and within, along with structural defects that are biocompatible with iron and sulfur. After being mixed with sodium bicarbonate and activated carbon and sintered, a bioselective iron-sulfur autotrophic denitrification packing material is formed. This invention relates to a method for preparing bioselective porous iron-sulfur autotrophic denitrification packing material, which has advantages such as simple process, green and efficient operation, and mild and controllable characteristics. Considering the needs of the wastewater treatment industry, this invention has enormous market application prospects and environmental and ecological significance. Attached Figure Description

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] Figure 1 This is a flow chart of the preparation process of the biological selective iron-sulfur autotrophic denitrification packing material of the present invention.

[0030] Figure 2The Fe k-edge X-ray near-edge absorption spectra of the iron-sulfur autotrophic denitrification packing material prepared by the biological selective porous iron-sulfur autotrophic denitrification packing material preparation method of the present invention and the iron-sulfur autotrophic denitrification packing material prepared by pyrite as the iron-sulfur mineral source without the microbial-mediated activation method of the present invention are obtained. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing and simplifying the invention, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more unless otherwise explicitly specified.

[0034] This embodiment provides a method for preparing a biologically selective porous iron-sulfur autotrophic denitrification packing material, referring to... Figure 1 This includes the following steps:

[0035] (1) The iron-sulfur minerals and sulfur were ground to -74 μm in a sample preparation machine, and then the iron-sulfur minerals were ball-milled to activate the surface to obtain surface-activated minerals;

[0036] (2) The surface-activated minerals obtained in step (1) were placed in 9K basal medium with an initial pH of 1.8 and inoculated with acidophilic iron-sulfur oxidizing microorganisms at a concentration of 1×10⁻⁶. 8 / mL, stirring speed 170 rpm. After activation, solid-liquid separation was performed to obtain aerobic activated ore;

[0037] (3) Add the aerobic activated mineral obtained in step (2) to fresh 9K basic culture medium, inoculate the bacterial mud separated from the filtrate in step (2), add elemental sulfur, adjust the initial pH to 1.8, use nitrogen to drive out the air in the reactor and seal it, stir at 170 rpm, and after activation, separate the solid and liquid to obtain anaerobic activated mineral.

[0038] (4) The anaerobic activated mineral obtained in step (3) is washed in 1 mol / L HCl solution and sterilized by ultraviolet light for 30 min. Then it is mixed with sodium bicarbonate and activated carbon in a sample preparation machine, followed by ball milling, pelletizing and sintering to obtain biological selective iron-sulfur autotrophic denitrification packing.

[0039] Furthermore, the iron-sulfur minerals mentioned in step (1) include at least one of pyrite, makinoite, pyrrhotite and marcasite.

[0040] Furthermore, the ball milling conditions described in step (1) are: ball-to-material ratio of 1.5 to 3:1, rotation speed of 200 to 400 rpm / min, and ball milling time of 0.5 to 3 h.

[0041] Furthermore, the activation conditions described in step (2) are: slurry concentration of 5~30 g / L, activation reaction temperature of 55~80°C, and activation reaction time of 12~144 h.

[0042] Furthermore, the inoculation of acidophilic iron-sulfur oxidizing microorganisms in step (2) mainly includes Bacillus cyclophosphamide (Sendai). 仙台 Alicyclobacillus ), Wanzao acidophilus ( 万座酸浆菌 Metallsulfuron-methyl ( 金属硫化叶菌 ) and diligent metallococci ( 嗜热栖热硫化叶菌 At least two of them.

[0043] Furthermore, the activation conditions described in step (3) are: slurry concentration of 5~30 g / L, elemental sulfur addition of 10~50 g / L, activation reaction temperature of 55~80°C, and activation reaction time of 48~168 h.

[0044] Furthermore, in step (3), the anaerobic activated ore is mixed with sodium bicarbonate and activated carbon at a mass ratio of 10~50:2~5:1, and the sintering temperature of the mixture is 70~110°C.

[0045] Figure 2This study presents Fe k-edge X-ray near-edge absorption spectra of iron-sulfur autotrophic denitrification packing material prepared using the bioselective porous iron-sulfur autotrophic denitrification packing material prepared according to the present invention and without microbial-mediated activation by the method of the present invention, using pyrite as the iron-sulfur mineral source (K-edge XANES of packing material (a) without activation by the method of the present invention and packing material (b) synthesized by activation by the method of the present invention). The results show that the pyrite structure on the surface of the packing material obtained by the method of the present invention is effectively activated, producing more metastable ferrous sulfate and ferric sulfate.

[0046] To highlight the technical challenges, solutions, and advantages of this invention, specific embodiments are described in detail below.

[0047] Comparative Example 1

[0048] Pyrite and sulfur were ground to -74 μm in a sample preparation machine, and then the surface of the pyrite was activated by ball milling to obtain surface-activated ore. The ball-to-material ratio was 3:1, the rotation speed was 400 rpm / min, and the ball milling time was 2 h. The obtained surface-activated ore was placed in 9K basal medium with an initial pH of 1.8 and inoculated with Bacillus cyclophosphamide (Sendai). 仙台 Alicyclobacillus ), Wanzao acidophilus ( 万座酸浆菌 The inoculation concentration was 1×10⁻⁶. 8 The mixture was aerobically activated for 144 h at a stirring speed of 170 rpm, a slurry concentration of 10 g / L, and an activation temperature of 70°C, followed by solid-liquid separation to obtain aerobic activated ore. The aerobic activated ore was added to fresh 9K basal medium, inoculated with bacterial sludge separated from the aerobic activation filtrate, and elemental sulfur was added to adjust the initial pH to 1.8. The reactor was then sealed after purging air with nitrogen and subjected to anaerobic reaction for 24 h at a stirring speed of 170 rpm, a slurry concentration of 10 g / L, an elemental sulfur addition of 10 g / L, and an activation temperature of 65°C. After activation, solid-liquid separation yielded anaerobic activated ore. The anaerobic activated ore was mixed with sodium bicarbonate and activated carbon at a mass ratio of 30:3:1, followed by ball milling, pelletizing, and sintering at 80°C to obtain a bioselective porous iron-sulfur autotrophic denitrification packing. A biofilter was prepared, and the bioselective porous iron-sulfur autotrophic packing was added at a volume ratio of 1:20. Iron-sulfur autotrophic denitrifying bacteria were inoculated into the biological filter at a concentration of 1×10⁻⁶. 8 / mL. The NO3-N concentration in the influent was 60 mg / L. Water was circulated in via a pump, with a start-up time of 7 days. At this point, the microbial adsorption capacity on the packing surface was 2.7 × 10⁻⁶. 8 / g. It is evident that a short anaerobic activation time severely affects the experimental results.

[0049] Comparative Example 2

[0050] Pyrite and sulfur were ground to -74 μm in a sample preparation machine, and then the surface of the pyrite was activated by ball milling to obtain surface-activated ore. The ball-to-material ratio was 3:1, the rotation speed was 400 rpm / min, and the ball milling time was 2 h. The obtained surface-activated ore was placed in 9K basal medium with an initial pH of 1.8 and inoculated with Bacillus cyclophosphamide (Sendai). 仙台 Alicyclobacillus ), Wanzao acidophilus ( 万座酸浆菌 The inoculation concentration was 1×10⁻⁶. 8 The slurry was aerobically activated for 36 h at a stirring speed of 170 rpm, a slurry concentration of 10 g / L, and an activation temperature of 70°C, followed by solid-liquid separation to obtain aerobic activated ore. The aerobic activated ore was added to fresh 9K basal medium, inoculated with bacterial sludge separated from the aerobic activation filtrate, and elemental sulfur was added to adjust the initial pH to 1.8. The reactor was then sealed after purging air with nitrogen and subjected to anaerobic reaction for 72 h at a stirring speed of 170 rpm, a slurry concentration of 10 g / L, an elemental sulfur addition of 20 g / L, and an activation temperature of 75°C. After activation, solid-liquid separation yielded anaerobic activated ore. The anaerobic activated ore was mixed with sodium bicarbonate and activated carbon at a mass ratio of 30:3:1, followed by ball milling, pelletizing, and sintering at 80°C to obtain a bioselective porous iron-sulfur autotrophic denitrification packing. A biofilter was prepared, and the bioselective porous iron-sulfur autotrophic packing was added at a volume ratio of 1:20. Iron-sulfur autotrophic denitrifying bacteria were inoculated into the biological filter at a concentration of 1×10⁻⁶. 8 / mL. The NO3-N concentration in the influent was 60 mg / L. Water was circulated in via a pump, with a start-up time of 7 days. At this point, the microbial adsorption capacity on the packing surface was 1.9 × 10⁻⁶. 8 / g. It is evident that a short aerobic activation time severely affects the experimental results.

[0051] Comparative Example 3

[0052] Maginot ore and sulfur were ground to -74 μm in a sample preparation machine. The Maginot ore was then ball-milled to activate its surface, resulting in a surface-activated ore. The ball-to-material ratio was 3:1, the milling speed was 400 rpm / min, and the milling time was 2 h. The obtained surface-activated ore was placed in 9K basal medium, initially pH 1.8, and inoculated with *Bacillus sendaiensis* (…). Alicyclobacillus sendaiensis ), Wanzao acidophilus ( 万座酸浆菌 The inoculation concentration was 1×10⁻⁶. 8The slurry was aerobically activated for 144 h at a stirring speed of 170 rpm, a slurry concentration of 10 g / L, and an activation temperature of 70°C. Solid-liquid separation was then performed to obtain aerobic activated ore. The aerobic activated ore was added to fresh 9K basal culture medium, inoculated with bacterial sludge separated from the aerobic activation filtrate, and elemental sulfur was added to adjust the initial pH to 1.8. The reactor was then sealed after purging air with nitrogen and subjected to anaerobic reaction for 72 h at a stirring speed of 170 rpm, a slurry concentration of 10 g / L, an elemental sulfur addition of 20 g / L, and an activation temperature of 75°C. Solid-liquid separation was performed after activation to obtain anaerobic activated ore. The obtained anaerobic activated ore was mixed with sodium bicarbonate and activated carbon at a mass ratio of 30:3:1, followed by ball milling, pelletizing, and sintering at 90°C to obtain a bioselective porous iron-sulfur autotrophic denitrification packing. A biofilter was prepared, and the bioselective porous iron-sulfur autotrophic packing was added at a volume ratio of 1:20. Iron-sulfur autotrophic denitrifying bacteria were inoculated into the biological filter at a concentration of 1×10⁻⁶. 8 / mL. The NO3-N concentration in the influent was 60 mg / L. Water was circulated in via a pump, with a start-up time of 7 days. At this point, the microbial adsorption capacity on the packing surface was 2.3 × 10⁻⁶. 8 / g. It is evident that the limited selection of Maginot ore electron donors significantly impacts the experimental results.

[0053] Example 1

[0054] Pyrite and sulfur were ground to -74 μm in a sample preparation machine, and then the surface of the pyrite was activated by ball milling to obtain surface-activated ore. The ball-to-material ratio was 3:1, the rotation speed was 400 rpm / min, and the ball milling time was 2 h. The obtained surface-activated ore was placed in 9K basal medium with an initial pH of 1.8 and inoculated with Bacillus cyclophosphamide (Sendai). 仙台 Alicyclobacillus ), Wanzao acidophilus ( 万座酸浆菌 The inoculation concentration was 1×10⁻⁶. 8The slurry was aerobically activated for 144 h at a stirring speed of 170 rpm, a slurry concentration of 10 g / L, and an activation temperature of 75°C. Solid-liquid separation was then performed to obtain aerobic activated ore. The aerobic activated ore was added to fresh 9K basal culture medium, inoculated with bacterial sludge separated from the aerobic activation filtrate, and elemental sulfur was added to adjust the initial pH to 1.8. The reactor was then sealed after purging air with nitrogen and subjected to anaerobic reaction for 72 h at a stirring speed of 170 rpm, a slurry concentration of 10 g / L, an elemental sulfur addition of 20 g / L, and an activation temperature of 75°C. Solid-liquid separation was performed after activation to obtain anaerobic activated ore. The obtained anaerobic activated ore was mixed with sodium bicarbonate and activated carbon at a mass ratio of 40:3:1, followed by ball milling, pelletizing, and sintering at 80°C to obtain a bioselective porous iron-sulfur autotrophic denitrification packing. A biofilter was prepared, and the bioselective porous iron-sulfur autotrophic packing was added at a volume ratio of 1:20. Iron-sulfur autotrophic denitrifying bacteria were inoculated into the biological filter at a concentration of 1×10⁻⁶. 8 / mL. The NO3-N concentration in the influent was 60 mg / L. Water was circulated in via a pump, with a start-up time of 7 days. At this point, the microbial adsorption capacity on the packing surface was 4.8 × 10⁻⁶. 8 / g.

[0055] Example 2

[0056] Pyrrhotite and sulfur were ground to -74 μm in a sample preparation machine. The pyrrhotite was then ball-milled to activate its surface, yielding a surface-activated ore. The ball-to-material ratio was 3:1, the milling speed was 400 rpm / min, and the milling time was 3 h. The resulting surface-activated ore was placed in 9K basal medium, initially pH 1.8, and inoculated with *Bacillus cyclophosphamide* (Sendai). Alicyclobacillus sendaiensis ), Wanzao acidophilus ( 万座酸浆菌 The inoculation concentration was 1×10⁻⁶. 8The mixture was aerobically activated for 168 h at a stirring speed of 170 rpm, a slurry concentration of 10 g / L, and an activation temperature of 75°C, followed by solid-liquid separation to obtain aerobic activated ore. The aerobic activated ore was added to fresh 9K basal culture medium, inoculated with bacterial sludge separated from the aerobic activation filtrate, and elemental sulfur was added to adjust the initial pH to 1.8. The reactor was then sealed after purging air with nitrogen and subjected to anaerobic reaction for 96 h at a stirring speed of 170 rpm, a slurry concentration of 10 g / L, an elemental sulfur addition of 20 g / L, and an activation temperature of 75°C. After activation, solid-liquid separation yielded anaerobic activated ore. The anaerobic activated ore was mixed with sodium bicarbonate and activated carbon at a mass ratio of 40:4:1, followed by ball milling, pelletizing, and sintering at 90°C to obtain a bioselective porous iron-sulfur autotrophic denitrification packing. A biofilter was prepared, and the bioselective porous iron-sulfur autotrophic packing was added at a volume ratio of 1:20. Iron-sulfur autotrophic denitrifying bacteria were inoculated into the biological filter at a concentration of 1×10⁻⁶. 8 / mL. The NO3-N concentration in the influent was 60 mg / L. Water was circulated in via a pump, with a start-up time of 7 days. At this point, the microbial adsorption capacity on the packing surface was 4.2 × 10⁻⁶. 8 / g.

[0057] Example 3

[0058] Pyrite and sulfur were ground to -74 μm in a sample preparation machine, and then pyrrhotite was ball-milled to activate the surface, resulting in a surface-activated ore. The ball-to-material ratio was 3:1, the milling speed was 400 rpm / min, and the milling time was 3 h. The obtained surface-activated ore was placed in 9K basal medium with an initial pH of 1.8 and inoculated with *Thiopyrophyllus metalloids* (…). 金属硫化叶菌 ) and diligent metallococci ( 嗜热栖热硫化叶菌 The inoculation concentration was 1×10⁻⁶. 8 The slurry was aerobically activated for 168 h at a stirring speed of 170 rpm, a slurry concentration of 10 g / L, and an activation temperature of 80°C. Solid-liquid separation was then performed to obtain aerobic activated ore. The aerobic activated ore was added to fresh 9K basal culture medium, inoculated with bacterial sludge separated from the aerobic activation filtrate, and elemental sulfur was added to adjust the initial pH to 1.8. The reactor was then sealed after purging air with nitrogen and subjected to anaerobic reaction for 96 h at a stirring speed of 170 rpm, a slurry concentration of 10 g / L, an elemental sulfur addition of 20 g / L, and an activation temperature of 80°C. Solid-liquid separation was performed after activation to obtain anaerobic activated ore. The obtained anaerobic activated ore was mixed with sodium bicarbonate and activated carbon at a mass ratio of 40:4:1, followed by ball milling, pelletizing, and sintering at 90°C to obtain a bioselective porous iron-sulfur autotrophic denitrification packing. A biofilter was prepared, and the bioselective porous iron-sulfur autotrophic packing was added at a volume ratio of 1:20. Iron-sulfur autotrophic denitrifying bacteria were inoculated into the biological filter at a concentration of 1×10⁻⁶.8 / mL. The NO3-N concentration in the influent was 60 mg / L. Water was circulated in via a pump, with a start-up time of 7 days. At this point, the microbial adsorption capacity on the packing surface was 5.1 × 10⁻⁶. 8 / g.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a biologically selective porous iron-sulfur autotrophic denitrification packing, characterized in that, Includes the following steps: (1) The iron-sulfur minerals and sulfur were ground to 74 μm in a sample preparation machine, and then the iron-sulfur minerals were ball-milled to activate the surface to obtain surface-activated minerals; (2) The surface-activated minerals obtained in step (1) were placed in 9K basal medium with an initial pH of 1.8 and inoculated with acidophilic iron-sulfur oxidizing microorganisms at a concentration of 1×10⁻⁶. 8 / mL, stirring speed 170 rpm, after activation, solid-liquid separation was performed to obtain aerobic activated ore; (3) Add the aerobic activated mineral obtained in step (2) to fresh 9K basic culture medium, inoculate the bacterial mud separated from the filtrate in step (2), add sulfur, adjust the initial pH to 1.8, use nitrogen to drive out the air in the reactor and seal it, stir at 170 rpm, and after activation, separate the solid and liquid to obtain anaerobic activated mineral. (4) The anaerobic activated mineral obtained in step (3) was washed in 1 mol / L HCl solution and sterilized by ultraviolet light for 30 min. Then it was mixed with sodium bicarbonate and activated carbon in a sample preparation machine, followed by ball milling, pelletizing and sintering to obtain biological selective iron-sulfur autotrophic denitrification packing. The activation conditions described in step (2) are: pulp concentration of 5~30 g / L, activation reaction temperature of 55~80°C, and activation reaction time of 144 h or 168 h; The activation conditions described in step (3) are: slurry concentration of 5~30 g / L, sulfur addition of 10~50 g / L, activation reaction temperature of 55~80°C, and activation reaction time of 48~168 h.

2. The method for preparing a bioselective porous iron-sulfur autotrophic denitrification packing material according to claim 1, characterized in that, The iron-sulfur minerals mentioned in step (1) include at least one of pyrite, pyrrhotite and marcasite.

3. The method for preparing a bioselective porous iron-sulfur autotrophic denitrification packing material according to claim 1, characterized in that, The ball milling conditions described in step (1) are: ball-to-material ratio of 1.5 to 3:1, rotation speed of 200 to 400 rpm, and ball milling time of 0.5 to 3 hours.

4. The method for preparing a biologically selective porous iron-sulfur autotrophic denitrification packing material according to claim 1, characterized in that, The acidophilic iron-sulfur oxidizing microorganisms mentioned in step (2) include at least two of the following: Bacillus cyclosporum sendaiensis, Bacillus manzaiensis, Bacillus metalloidus, and Bacillus thuringiensis.

5. The method for preparing a bioselective porous iron-sulfur autotrophic denitrification packing material according to claim 1, characterized in that, In step (3), the anaerobic activated ore is mixed with sodium bicarbonate and activated carbon at a mass ratio of 10~50:2~5:1, and the sintering temperature of the mixture is 70~110°C.

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