Preparation method of biological selective porous iron-sulfur autotrophic denitrification filler

Abstract

The invention discloses a preparation method of a biological selective porous iron-sulfur autotrophic denitrification filler. The preparation method comprises the following steps: respectively grinding pyrite and sulfur in a sampling machine to-74 microns, and then carrying out ball milling; carrying out aerobic biological activation on the ball-milled pyrite powder in a 9K basic culture medium, and then carrying out solid-liquid separation to obtain aerobic activated ore; after a fresh culture medium is replaced, sulfur is added, nitrogen is used for blowing air to conduct anaerobic biological activation, then solid-liquid separation is conducted, and anaerobic activated ore is obtained; and cleaning the surface of the obtained anaerobic activated ore with diluted hydrochloric acid, mixing with sodium bicarbonate and activated carbon, ball-milling, pelletizing and sintering at low temperature to obtain the biological selective porous iron-sulfur autotrophic denitrification filler. According to the preparation method of the biological selective porous iron-sulfur autotrophic denitrification filler, the raw materials are wide in source and low in cost, adsorption growth of iron-sulfur autotrophic microorganisms can be selectively promoted, and the ideal effects of advanced sewage treatment and nitrogen and phosphorus removal can be achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a method for preparing a biologically selective porous iron-sulfur autotrophic denitrification filler. Background Art

[0002] With the improvement of sewage treatment rate, sludge disposal rate and emission standards, the energy consumption of sewage treatment will further increase. Under the background of dual carbon, it is an inevitable trend for the development of sewage treatment industry to promote the upgrading and transformation of key industries such as sewage treatment, develop efficient sewage treatment technology with energy saving and consumption reduction, and take into account efficient nitrogen / phosphorus removal and energy consumption reduction. It has great environmental, ecological and economic significance for promoting the sewage treatment industry to achieve green and low carbon and alleviate its carbon emission pressure.

[0003] Sulfur autotrophic denitrification technology is a process in which autotrophic Thiobacillus utilizes reduced sulfur (H2S, S 2- 、S2O3 2- ) as electron donor, with NO3 2- / NO2 - The technology of denitrification as an electron acceptor (can achieve efficient nitrate nitrogen removal under non-organic carbon dependent conditions). However, this process also has some disadvantages, such as the production of acid and sulfate, which promotes NO2 - As we all know, the biological oxidation process of iron often consumes protons, and the iron autotrophic denitrification process is based on Fe 0 / Fe 2+ It is an electron donor. Combining the iron and sulfur autotrophic denitrification processes to form an iron-sulfur autotrophic denitrification process can not only consume the acid produced by the sulfur autotrophic process, but also promote the coordinated transformation of iron and sulfur forms, and couple the phosphorus form transformation process, which is beneficial to the simultaneous removal of nitrogen and phosphorus. In addition, it can further improve the nitrogen removal efficiency, achieve the coordinated removal of carbon, nitrogen and phosphorus under low carbon-nitrogen ratio, low aeration volume and no carbon source, and avoid SO4 2- excessive accumulation.

[0004] At present, there is a lack of reasonable preparation methods for bioselective porous iron-sulfur autotrophic denitrification fillers, which to some extent restricts the combination of iron and sulfur autotrophic denitrification processes. Summary of the invention

[0005] Based on the technical problems raised in the background technology, the purpose of the present invention is to provide a method for preparing a biologically selective porous iron-sulfur autotrophic denitrification filler to selectively promote the biofilm formation process of iron-sulfur autotrophic microorganisms, accelerate the iron-sulfur autotrophic startup process, and improve the nitrogen and phosphorus removal treatment efficiency.

[0006] The present invention provides a method for preparing a biologically selective porous iron-sulfur autotrophic denitrification filler, comprising the following steps: (1) Grinding the iron-sulfur mineral and sulfur to -74 μm in a sample preparation machine respectively, and then ball-milling the iron-sulfur mineral to activate the surface to obtain a surface-activated ore; (2) The surface activated mineral obtained in step (1) was placed in 9K basal medium, with an initial pH of 1.8, and inoculated with acidophilic iron-sulfur oxidizing microorganisms at an inoculation concentration of 1×10 8 / mL, stirring speed 170 rpm, solid-liquid separation after activation, to obtain aerobic activated ore; (3) Add the aerobic activated ore obtained in step (2) to fresh 9K basal medium, inoculate the bacterial sludge separated from the filtrate of step (2), add elemental sulfur, adjust the initial pH to 1.8, drive out the air in the reactor with nitrogen and seal it, stir at 170 rpm, separate the solid and liquid after activation, and obtain the anaerobic activated ore; (4) The anaerobic activated ore obtained in step (3) is added to a 1 mol / L HCl solution for cleaning and UV sterilization for 30 min, and then mixed with sodium bicarbonate and activated carbon in a sample preparation machine, followed by ball milling, balling, and sintering to obtain a bioselective iron-sulfur autotrophic denitrification filler.

[0007] Furthermore, the iron-sulfur mineral in step (1) includes at least one of pyrite, maquinonite, pyrrhotite and marcasite.

[0008] Furthermore, the ball milling conditions in step (1) are: ball to material ratio 1.5-3:1, rotation speed 200-400 rpm / min, and ball milling time 0.5-3 h.

[0009] Furthermore, the activation conditions described in step (2) are: slurry concentration 5-30 g / L, activation reaction temperature 55-80°C, and activation reaction time 12-144 h.

[0010] Furthermore, the acidophilic iron-sulfur oxidizing microorganisms in step (2) mainly include Alicyclobacillus Sendai ( Alicyclobacillus sendaiensis ), Acidophilus manzae Acidianus manzaensis ), Metallosulfurobacterium ( Sulfolobus metallicus ) and Metallosphaeroides industris ( Metallosphaera sedula ) at least two of the following.

[0011] Furthermore, the activation conditions described in step (3) are: slurry concentration 5~30 g / L, elemental sulfur addition amount 10~50 g / L, activation reaction temperature 55~80°C, and activation reaction time 48~168 h.

[0012] Furthermore, the anaerobic activated ore in step (3) is mixed with sodium bicarbonate and activated carbon in a mass ratio of 10-50:2-5:1, and the mixture is sintered at a temperature of 70-110°C.

[0013] The surface activated slag of the present invention is obtained by ball milling the iron-sulfur mineral so that the surface layer lattice of the iron-sulfur mineral is mechanically activated and oxidized. This process can generate lattice defects on the surface of the iron-sulfur mineral, reduce the surface chemical energy, and facilitate the subsequent biological activation process.

[0014] The aerobic activated slag of the present invention is obtained by aerobic leaching activation of surface activated slag mediated by acidophilic iron-sulfur microorganisms. During the aerobic activation process, Fe is easily dissolved at the S defects of the surface activated slag and is oxidized into Fe by the acidophilic iron-sulfur microorganisms. 3+ Acidophilic iron-sulfur microorganisms bind Fe 3+ Further indirect oxidation of the surface of the iron-sulfur mineral components leads to corrosion pits and defects on the surface, as well as Fe 2+ This process can form a cycle under the mediation of acidophilic iron-sulfur microorganisms, continuously activating and corroding the surface of iron-sulfur minerals, making the surface hydrophobic and porous, which is easier for microorganisms to adsorb and react with iron-sulfur minerals. This process will also cause the accumulation of some elemental sulfur and secondary iron-vanadium substances on the surface, resulting in partial surface passivation.

[0015] The anaerobic activated slag of the present invention is obtained by anaerobic leaching activation of aerobic leaching slag mediated by acidophilic iron-sulfur microorganisms. During the anaerobic activation process, the dissolution of the iron-vanadium substances accumulated on the surface of the aerobic leaching slag is in a dynamic balance. The acidophilic iron-sulfur microorganisms can use the elemental sulfur accumulated on the surface of the aerobic leaching slag and added as an electron donor to reduce the Fe released by the dissolution of the iron-vanadium substances. 3+ , which causes the dissolution equilibrium of iron and vanadium substances to shift to the right, and continuously promotes their dissolution. This process can effectively remove the passivation components on the surface of aerobic activated slag.

[0016] The anaerobic leaching residue is washed in a 1 mol / L HCl solution and sterilized by ultraviolet for 30 min to remove the surface biofilm, and the bioselective porous filler of the present invention is obtained by sintering with activated carbon and sodium bicarbonate.

[0017] During ball milling, the ball-to-material ratio, rotation speed, and ball milling time need to be regulated. The ball-to-material ratio is required to be 1.5~3:1, the rotation speed is 200~400 rpm / min, and the ball milling time is 0.5~3 h to ensure that the microstructure of the iron-sulfur mineral can be activated and destroyed, thereby improving the efficiency of the subsequent activation reaction.

[0018] During aerobic activation, it is necessary to control the slurry concentration, activation reaction temperature and activation reaction time. The slurry concentration is required to be controlled at 5~30 g / L, the activation reaction temperature is 55~80°C, and the activation reaction time is 12~144 h to ensure that the acidophilic iron-sulfur microorganisms can fully erode the surface of the leached iron-sulfur minerals under aerobic conditions to produce a loose porous structure without excessive accumulation of iron-vanadium substances and elemental sulfur.

[0019] During anaerobic activation, it is necessary to control the slurry concentration, activation reaction temperature and activation reaction time. The required slurry concentration is 5~30 g / L, the elemental sulfur addition is 10~50 g / L, the activation reaction temperature is 55~80°C, and the activation reaction time is 48~168h to ensure that the acidophilic iron-sulfur microorganisms can fully decompose the surface accumulated elemental sulfur and iron-vanadium substance passivation layer under anaerobic conditions.

[0020] When the anaerobic activated ore is mixed with sodium bicarbonate and activated carbon in the sample making machine, the mass ratio is required to be 10~50:2~5:1 to ensure that the filler has iron-sulfur autotrophic denitrification substrate, sufficient pH buffering capacity and high electron transfer efficiency.

[0021] The beneficial effects of this method are as follows: Control the appropriate ball-to-material ratio, rotation speed, and ball milling time to fully mechanically activate the surface of the iron-sulfur mineral to produce lattice defects and improve the leaching activation performance of the iron-sulfur mineral; control the appropriate solid slurry concentration, activation reaction temperature, and activation reaction time to fully activate the iron-sulfur mineral and obtain a loose and porous surface structure; control the mass ratio of the anaerobic activated ore to sodium bicarbonate and activated carbon to ensure that the filler has an iron-sulfur autotrophic denitrification substrate, sufficient pH buffering capacity, and a high electron transfer efficiency.

[0022] In summary, the present invention can activate iron-sulfur minerals, form loose porous structures and iron-sulfur bio-affinity structural defects on the surface and inside of the minerals, and then form biologically selective iron-sulfur autotrophic denitrification fillers after being mixed with sodium bicarbonate and activated carbon for sintering. The present invention relates to a method for preparing biologically selective porous iron-sulfur autotrophic denitrification fillers, which has the advantages of simple process, green and efficient, mild and controllable. Considering the needs of the sewage treatment industry, this invention has huge market application prospects and environmental and ecological significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0024] Figure 1 The present invention is a process flow chart for preparing the bioselective iron-sulfur autotrophic denitrification filler.

[0025] Figure 2 The present invention is a Fe k-edge X-ray near-edge absorption spectrum of an iron-sulfur autotrophic denitrification filler prepared by the method for preparing a biologically selective porous iron-sulfur autotrophic denitrification filler of the present invention and a filler not activated by microorganisms mediated by the method of the present invention, using pyrite as an iron-sulfur mineral source. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of description and simplified description of the present invention, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0028] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0029] This embodiment provides a method for preparing a biologically selective porous iron-sulfur autotrophic denitrification filler. Figure 1 , including the following steps: (1) Grinding the iron-sulfur mineral and sulfur to -74 μm in a sample preparation machine respectively, and then ball-milling the iron-sulfur mineral to activate the surface to obtain a surface-activated ore; (2) The surface activated mineral obtained in step (1) was placed in 9K basal medium, with an initial pH of 1.8, and inoculated with acidophilic iron-sulfur oxidizing microorganisms at an inoculation concentration of 1×10 8 / mL, stirring speed 170 rpm. After activation, solid-liquid separation was performed to obtain aerobic activated ore; (3) Add the aerobic activated ore obtained in step (2) to fresh 9K basal medium, inoculate the bacterial sludge separated from the filtrate of step (2), add elemental sulfur, adjust the initial pH to 1.8, drive out the air in the reactor with nitrogen and seal it, stir at 170 rpm, separate the solid and liquid after activation, and obtain the anaerobic activated ore; (4) The anaerobic activated ore obtained in step (3) is added to a 1 mol / L HCl solution for cleaning and UV sterilization for 30 min, and then mixed with sodium bicarbonate and activated carbon in a sample preparation machine, followed by ball milling, balling, and sintering to obtain a bioselective iron-sulfur autotrophic denitrification filler.

[0030] Furthermore, the iron-sulfur mineral in step (1) includes at least one of pyrite, maquinonite, pyrrhotite and marcasite.

[0031] Furthermore, the ball milling conditions in step (1) are: ball to material ratio 1.5-3:1, rotation speed 200-400 rpm / min, and ball milling time 0.5-3 h.

[0032] Furthermore, the activation conditions described in step (2) are: slurry concentration 5-30 g / L, activation reaction temperature 55-80°C, and activation reaction time 12-144 h.

[0033] Furthermore, the inoculated acidophilic iron-sulfur oxidizing microorganisms in step (2) mainly include Alicyclobacillus Sendai ( Alicyclobacillus sendaiensis ), Acidophilus manzae Acidianus manzaensis ), Metallosulfurobacterium ( Sulfolobus metallicus ) and Metallosphaeroides industris ( Metallosphaera sedula ) at least two of the following.

[0034] Furthermore, the activation conditions described in step (3) are: slurry concentration 5~30 g / L, elemental sulfur addition amount 10~50 g / L, activation reaction temperature 55~80°C, and activation reaction time 48~168 h.

[0035] Furthermore, the anaerobic activated ore in step (3) is mixed with sodium bicarbonate and activated carbon in a mass ratio of 10-50:2-5:1, and the mixture is sintered at a temperature of 70-110°C.

[0036] Figure 2 The Fe k-edge X-ray near-edge absorption spectra of the iron-sulfur autotrophic denitrification filler prepared by the method for preparing the biologically selective porous iron-sulfur autotrophic denitrification filler of the present invention and the filler without microbial mediated activation by the method of the present invention, using pyrite as the iron-sulfur mineral source (K-edge XANES of the filler (a) without activation by the method of the present invention and the filler (b) activated by the method of the present invention). The results show that the pyrite structure on the surface of the filler obtained by the method of the present invention is effectively activated, and more metastable ferrous sulfate and ferric sulfate are produced.

[0037] In order to highlight the technical problems, technical solutions and advantages to be solved by the present invention, specific embodiments are described in detail below.

[0038] Comparative Example 1 Pyrite and sulfur were ground to -74 μm in a sample preparation machine, and then the pyrite was ball-milled to activate the surface to obtain a surface-activated ore, with a ball-to-material ratio of 3:1, a rotation speed of 400 rpm / min, and a ball-milling time of 2 h. The surface-activated ore was placed in 9K basal medium with an initial pH of 1.8 and inoculated with Alicyclobacillus Sendai ( Alicyclobacillus sendaiensis ), Acidophilus manzae Acidianus manzaensis ), the inoculation concentration was 1×10 8 / mL, aerobic activation for 144 h at a stirring speed of 170 rpm, a pulp concentration of 10 g / L, and an activation reaction temperature of 70°C, followed by solid-liquid separation to obtain an aerobic activated ore; the obtained aerobic activated ore was added to a fresh 9K basal medium, inoculated with the bacterial sludge separated from the aerobic activation filtrate, added with elemental sulfur, the initial pH was adjusted to 1.8, the air in the reactor was driven out with nitrogen and sealed, and the anaerobic reaction time was 24 h at a stirring speed of 170 rpm, a pulp concentration of 10 g / L, an elemental sulfur addition of 10 g / L, and an activation reaction temperature of 65°C. After activation, solid-liquid separation was performed to obtain an anaerobic activated ore; the obtained anaerobic activated ore was mixed with sodium bicarbonate and activated carbon in a mass ratio of 30:3:1, and then ball-milled, balled, and sintered at 80°C to obtain a biologically selective porous iron-sulfur autotrophic denitrification filler. A biological filter was prepared, and the biologically selective porous iron-sulfur autotrophic filler was added in a volume ratio of 1:20. The iron-sulfur autotrophic denitrifying bacteria were inoculated into the biofilter at a concentration of 1×10 8 / mL. The NO3-N concentration in the influent was 60 mg / L. The water was circulated by a water pump and the start time was set to 7 days. At this time, the microbial adsorption on the filler surface was 2.7×10 8 / g. It can be seen that too short anaerobic activation time seriously affects the experimental results.

[0039] Comparative Example 2 Pyrite and sulfur were ground to -74 μm in a sample preparation machine, and then the pyrite was ball-milled to activate the surface to obtain a surface-activated ore, with a ball-to-material ratio of 3:1, a rotation speed of 400 rpm / min, and a ball-milling time of 2 h. The surface-activated ore was placed in 9K basal medium with an initial pH of 1.8 and inoculated with Alicyclobacillus Sendai ( Alicyclobacillus sendaiensis ), Acidophilus manzae Acidianus manzaensis ), the inoculation concentration was 1×10 8 / mL, aerobic activation for 36 h at a stirring speed of 170 rpm, a pulp concentration of 10 g / L, and an activation reaction temperature of 70°C, followed by solid-liquid separation to obtain an aerobic activated ore; the obtained aerobic activated ore was added to a fresh 9K basal medium, inoculated with the bacterial sludge separated from the aerobic activation filtrate, added with elemental sulfur, the initial pH was adjusted to 1.8, the air in the reactor was driven out with nitrogen and sealed, and the anaerobic reaction time was 72 h at a stirring speed of 170 rpm, a pulp concentration of 10 g / L, an elemental sulfur addition of 20 g / L, and an activation reaction temperature of 75°C. After activation, solid-liquid separation was performed to obtain an anaerobic activated ore; the obtained anaerobic activated ore was mixed with sodium bicarbonate and activated carbon in a mass ratio of 30:3:1, and then ball-milled, balled, and sintered at 80°C to obtain a biologically selective porous iron-sulfur autotrophic denitrification filler. A biological filter was prepared, and the biologically selective porous iron-sulfur autotrophic filler was added in a volume ratio of 1:20. The iron-sulfur autotrophic denitrifying bacteria were inoculated into the biofilter at a concentration of 1×10 8 / mL. The NO3-N concentration in the influent was 60 mg / L. The water was circulated by a water pump and the start time was set to 7 days. At this time, the microbial adsorption on the filler surface was 1.9×10 8 / g. It can be seen that a too short aerobic activation time seriously affects the experimental results.

[0040] Comparative Example 3 Magnolia ore and sulfur were ground to -74 μm in a sample preparation machine, and then the surface of Magnolia ore was activated by ball milling to obtain surface activated ore, with a ball-to-material ratio of 3:1, a rotation speed of 400 rpm / min, and a ball milling time of 2 h. The surface activated ore was placed in 9K basal medium with an initial pH of 1.8 and inoculated with Alicyclobacillus Sendai ( Alicyclobacillus sendaiensis ), Acidophilus manzae Acidianus manzaensis ), the inoculation concentration was 1×10 8 / mL, aerobic activation for 144 h at a stirring speed of 170 rpm, a pulp concentration of 10 g / L, and an activation reaction temperature of 70°C, followed by solid-liquid separation to obtain an aerobic activated ore; the obtained aerobic activated ore was added to a fresh 9K basal medium, inoculated with the bacterial sludge separated from the aerobic activation filtrate, added with elemental sulfur, the initial pH was adjusted to 1.8, the air in the reactor was driven out with nitrogen and sealed, and the anaerobic reaction time was 72 h at a stirring speed of 170 rpm, a pulp concentration of 10 g / L, an elemental sulfur addition of 20 g / L, and an activation reaction temperature of 75°C. After activation, solid-liquid separation was performed to obtain an anaerobic activated ore; the obtained anaerobic activated ore was mixed with sodium bicarbonate and activated carbon in a mass ratio of 30:3:1, and then ball-milled, balled, and sintered at 90°C to obtain a biologically selective porous iron-sulfur autotrophic denitrification filler. A biological filter was prepared, and the biologically selective porous iron-sulfur autotrophic filler was added in a volume ratio of 1:20. The iron-sulfur autotrophic denitrifying bacteria were inoculated into the biofilter at a concentration of 1×10 8 / mL. The NO3-N concentration in the influent was 60 mg / L. The water was circulated by a water pump and the start time was set to 7 days. At this time, the microbial adsorption on the filler surface was 2.3×10 8 / g. It can be seen that the selection of Makino ore with fewer electron donors seriously affects the experimental results.

[0041] Example 1 Pyrite and sulfur were ground to -74 μm in a sample preparation machine, and then the pyrite was ball-milled to activate the surface to obtain a surface-activated ore, with a ball-to-material ratio of 3:1, a rotation speed of 400 rpm / min, and a ball-milling time of 2 h. The surface-activated ore was placed in 9K basal medium with an initial pH of 1.8 and inoculated with Alicyclobacillus Sendai ( Alicyclobacillus sendaiensis ), Acidophilus manzae Acidianus manzaensis ), the inoculation concentration was 1×10 8 / mL, aerobic activation for 144 h at a stirring speed of 170 rpm, a pulp concentration of 10 g / L, and an activation reaction temperature of 75°C, followed by solid-liquid separation to obtain an aerobic activated ore; the obtained aerobic activated ore was added to a fresh 9K basal medium, inoculated with the bacterial sludge separated from the aerobic activation filtrate, added with elemental sulfur, adjusted to an initial pH of 1.8, and the air in the reactor was driven out with nitrogen and sealed, and the anaerobic reaction time was 72 h at a stirring speed of 170 rpm, a pulp concentration of 10 g / L, an elemental sulfur addition of 20 g / L, and an activation reaction temperature of 75°C. After activation, solid-liquid separation was performed to obtain an anaerobic activated ore; the obtained anaerobic activated ore was mixed with sodium bicarbonate and activated carbon in a mass ratio of 40:3:1, and then ball-milled, balled, and sintered at 80°C to obtain a biologically selective porous iron-sulfur autotrophic denitrification filler. A biological filter was prepared, and the biologically selective porous iron-sulfur autotrophic filler was added in a volume ratio of 1:20. The iron-sulfur autotrophic denitrifying bacteria were inoculated into the biofilter at a concentration of 1×10 8 / mL. The NO3-N concentration in the influent was 60 mg / L. The water was circulated by a water pump and the start time was set to 7 days. At this time, the microbial adsorption on the filler surface was 4.8×10 8 / g.

[0042] Example 2 Pyrrhotite and sulfur were ground to -74 μm in a sample preparation machine, and then the surface of pyrrhotite was activated by ball milling to obtain surface activated ore, with a ball-to-material ratio of 3:1, a rotation speed of 400 rpm / min, and a ball milling time of 3 h. The surface activated ore was placed in 9K basal medium with an initial pH of 1.8 and inoculated with Alicyclobacillus Sendai ( Alicyclobacillus sendaiensis ), Acidophilus manzae Acidianus manzaensis ), the inoculation concentration was 1×10 8 / mL, aerobic activation for 168 h at a stirring speed of 170 rpm, a pulp concentration of 10 g / L, and an activation reaction temperature of 75°C, followed by solid-liquid separation to obtain an aerobic activated ore; the obtained aerobic activated ore was added to a fresh 9K basal medium, inoculated with the bacterial sludge separated from the aerobic activation filtrate, added with elemental sulfur, the initial pH was adjusted to 1.8, the air in the reactor was driven out with nitrogen and sealed, and the anaerobic reaction time was 96 h at a stirring speed of 170 rpm, a pulp concentration of 10 g / L, an elemental sulfur addition of 20 g / L, and an activation reaction temperature of 75°C. After activation, solid-liquid separation was performed to obtain an anaerobic activated ore; the obtained anaerobic activated ore was mixed with sodium bicarbonate and activated carbon in a mass ratio of 40:4:1, and then ball-milled, balled, and sintered at 90°C to obtain a biologically selective porous iron-sulfur autotrophic denitrification filler. A biological filter was prepared, and the biologically selective porous iron-sulfur autotrophic filler was added in a volume ratio of 1:20. The iron-sulfur autotrophic denitrifying bacteria were inoculated into the biofilter at a concentration of 1×10 8 / mL. The NO3-N concentration in the influent was 60 mg / L. The water was circulated by a water pump and the start time was set to 7 days. At this time, the microbial adsorption on the filler surface was 4.2×10 8 / g.

[0043] Example 3 Pyrite and sulfur were ground to -74 μm in a sample preparation machine, and then the surface of pyrrhotite was activated by ball milling to obtain a surface activated ore, with a ball-to-material ratio of 3:1, a rotation speed of 400 rpm / min, and a ball milling time of 3 h. The surface activated ore was placed in 9K basic culture medium with an initial pH of 1.8 and inoculated with Metallosulphobium ( Sulfolobus metallicus ) and Metallosphaeroides industris ( Metallosphaera sedula ), the inoculation concentration was 1×10 8 / mL, aerobic activation for 168 h at a stirring speed of 170 rpm, a slurry concentration of 10 g / L, and an activation reaction temperature of 80°C, followed by solid-liquid separation to obtain an aerobic activated ore; the obtained aerobic activated ore was added to a fresh 9K basal medium, inoculated with the bacterial sludge separated from the aerobic activation filtrate, added with elemental sulfur, the initial pH was adjusted to 1.8, the air in the reactor was driven out with nitrogen and sealed, and the anaerobic reaction time was 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 reaction temperature of 80°C. After activation, solid-liquid separation was performed to obtain an anaerobic activated ore; the obtained anaerobic activated ore was mixed with sodium bicarbonate and activated carbon in a mass ratio of 40:4:1, and then ball-milled, balled, and sintered at 90°C to obtain a biologically selective porous iron-sulfur autotrophic denitrification filler. A biological filter was prepared, and the biologically selective porous iron-sulfur autotrophic filler was added in a volume ratio of 1:20. The iron-sulfur autotrophic denitrifying bacteria were inoculated into the biofilter at a concentration of 1×10 8 / mL. The NO3-N concentration in the influent was 60 mg / L. The water was circulated by a water pump and the start time was set to 7 days. At this time, the microbial adsorption on the filler surface was 5.1×10 8 / g.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for preparing a biologically selective porous iron-sulfur autotrophic denitrification filler, characterized in that: The following steps are involved: (1) Grinding the iron-sulfur mineral and sulfur to -74 μm in a sample preparation machine respectively, and then ball-milling the iron-sulfur mineral to activate the surface to obtain a surface-activated ore; (2) The surface activated mineral obtained in step (1) was placed in 9K basal medium, with an initial pH of 1.8, and inoculated with acidophilic iron-sulfur oxidizing microorganisms at an inoculation concentration of 1×10 8 / mL, stirring speed 170 rpm, solid-liquid separation after activation, to obtain aerobic activated ore; (3) Add the aerobic activated ore obtained in step (2) to fresh 9K basal medium, inoculate the bacterial sludge separated from the filtrate of step (2), add elemental sulfur, adjust the initial pH to 1.8, drive out the air in the reactor with nitrogen and seal it, stir at 170 rpm, separate the solid and liquid after activation, and obtain the anaerobic activated ore; (4) The anaerobic activated ore obtained in step (3) is added to a 1 mol / L HCl solution for cleaning and UV sterilization for 30 min, and then mixed with sodium bicarbonate and activated carbon in a sample preparation machine, followed by ball milling, balling, and sintering to obtain a bioselective iron-sulfur autotrophic denitrification filler.

2. A method for preparing a biologically selective porous iron-sulfur autotrophic denitrification filler according to claim 1, characterized in that: The iron-sulfur mineral in step (1) includes at least one of pyrite, maquinonite, pyrrhotite and marcasite.

3. The method for preparing a biologically selective porous iron-sulfur autotrophic denitrification filler according to claim 1, characterized in that: The ball milling conditions described in step (1) are: ball to material ratio 1.5~3:1, rotation speed 200~400 rpm / min, ball milling time 0.5~3 h.

4. The method for preparing a biologically selective porous iron-sulfur autotrophic denitrification filler according to claim 1, characterized in that: The activation conditions described in step (2) are: slurry concentration 5~30 g / L, activation reaction temperature 55~80°C, and activation reaction time 12~144 h.

5. The method for preparing a biologically selective porous iron-sulfur autotrophic denitrification filler according to claim 1, characterized in that: The acidophilic iron-sulfur oxidizing microorganisms described in step (2) mainly include at least two of Alicyclobacillus Sendai, Acidophilus Manza, Metallosulfurobacterium and Metallosphaera diversa.

6. The method for preparing a biologically selective porous iron-sulfur autotrophic denitrification filler according to claim 1, characterized in that: The activation conditions described in step (3) are: slurry concentration 5~30 g / L, elemental sulfur addition amount 10~50 g / L, activation reaction temperature 55~80°C, and activation reaction time 48~168 h.

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

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