Sulfur autotrophic nitrogen removal biological filler as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of sewage treatment, and particularly relates to a sulfur autotrophic nitrogen removal biological filler as well as a preparation method and application thereof. The preparation method of the sulfur autotrophic nitrogen removal biological filler comprises the following steps: mixing and heating sulfur powder, iron powder, a surfactant, activated carbon, amylose and water to obtain a molten fluid; the molten fluid and alkali are mixed for a disproportionation reaction, and a thickened substance is obtained; and molding the thickened substance to obtain the sulfur autotrophic denitrification biological filler. Alkali is introduced in the filler preparation process, sulfur is promoted to be subjected to disproportionation reaction, and electron donors sulfide (S2-) and sulfite (SO32-) required by sulfur autotrophic denitrification are generated in the filler. Therefore, the bio-availability of sulfur is improved, and more active electron donors are provided for subsequent denitrification application, so that the biofilm formation efficiency of a sulfur autotrophic denitrification system is improved, the starting speed and the operation effect of the process are effectively enhanced, and efficient and deep denitrification is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a sulfur autotrophic denitrification biological filler and a preparation method and application thereof. Background Art

[0002] With the rapid development of industrialization and urbanization, water pollution is becoming increasingly serious, among which nitrogen pollution is one of the main problems of water pollution. Traditional biological denitrification methods mainly include nitrification and denitrification processes. However, these biological denitrification methods have some limitations, such as the need for a large amount of organic carbon source, high energy consumption, and the generation of a large amount of residual sludge. Sulfur autotrophic denitrification, as a new type of biological denitrification technology, has the advantages of no need for external organic carbon source, low sludge production, and low operating cost, and has received widespread attention.

[0003] Sulfur autotrophic denitrification is a process in which sulfur autotrophic denitrifying bacteria use reduced sulfur (such as elemental sulfur, sulfide, thiosulfate, etc.) as an electron donor to reduce nitrate nitrogen to nitrogen gas under anoxic conditions. In the process of sulfur autotrophic denitrification, biological fillers, as carriers of microorganisms, play a vital role in the denitrification effect. At present, commonly used biological fillers mainly include ceramsite, activated carbon, plastics, etc. In recent years, denitrification fillers made of elemental sulfur as the matrix have been widely used. For example, composite fillers formed by combining sulfur particles with pyrite and gelatinized starch can not only achieve in-situ acid-base neutralization, but also greatly reduce the sulfate production in the system. However, the overall denitrification efficiency of the composite filler is low. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a sulfur autotrophic denitrification biological filler and its preparation method and application. The sulfur autotrophic denitrification biological filler prepared by the present invention can be used as a microbial carrier and a sulfur source donor for biological reactions, and can achieve efficient denitrification of nitrogen-containing wastewater.

[0005] The present invention provides a method for preparing a sulfur autotrophic denitrification biological filler, comprising the following steps:

[0006] mixing sulfur powder, iron powder, surfactant, activated carbon, amylose and water and heating them to obtain a molten fluid;

[0007] The molten fluid and alkali are mixed to carry out a disproportionation reaction to obtain a thickened material;

[0008] The thickened material is molded to obtain a sulfur autotrophic denitrification biological filler; the sulfur autotrophic denitrification biological filler contains S 2- and SO3 2- .

[0009] Preferably, the mass ratio of the sulfur powder to the iron powder is (60-80):(5-10).

[0010] Preferably, the particle size of the iron powder is 100-250 mesh.

[0011] Preferably, the surfactant is an anionic surfactant, and the anionic surfactant includes sodium alkylbenzene sulfonate and / or sodium fatty acid ester sulfonate.

[0012] Preferably, the mass ratio of the sulfur powder, iron powder, surfactant, activated carbon and amylose is (60-80):(5-10):(2-5):(5-10):(2-5).

[0013] Preferably, the heating temperature is 120-180° C., the heat preservation time is 10-40 min, the heating is accompanied by stirring, and the stirring speed is 80-200 rpm.

[0014] Preferably, the alkali is a hot alkali solution, the hot alkali solution is a sodium hydroxide solution, the concentration of the sodium hydroxide solution is 2-6 mol / L, the pH value is 12-14, and the temperature is 50-100°C.

[0015] Preferably, the temperature of the disproportionation reaction is 130-170° C., and the time is 10-40 min.

[0016] The present invention also provides a sulfur autotrophic denitrification biological filler obtained by the preparation method described in the above technical solution, wherein the sulfur autotrophic denitrification biological filler contains S 2- and SO3 2- .

[0017] The present invention also provides the use of the sulfur autotrophic denitrification biological filler described in the above technical solution in sewage denitrification treatment.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The invention provides a method for preparing a sulfur autotrophic denitrification biological filler, comprising the following steps: mixing sulfur powder, iron powder, surfactant, activated carbon, amylose and water and heating them to obtain a molten fluid; mixing the molten fluid and alkali to carry out a disproportionation reaction to obtain a thickened material; shaping the thickened material to obtain a sulfur autotrophic denitrification biological filler, wherein the sulfur autotrophic denitrification biological filler contains sulfur. 2- and SO3 2- .

[0020] In the process of preparing the filler, alkali is introduced to promote the disproportionation reaction of sulfur, and the electron donor sulfide (S) required for sulfur autotrophic denitrification is generated in the filler. 2- ) and sulfite (SO3 2-). This not only improves the bioavailability of sulfur, but also provides a more active electron donor for subsequent denitrification applications, thereby improving the biofilm formation efficiency of the sulfur autotrophic denitrification system, effectively enhancing the start-up speed and operation effect of the process, and achieving high efficiency and deep denitrification.

[0021] Meanwhile, the preparation raw material of the present invention includes iron powder, which can not only strengthen sulfur disproportionation in the preparation process, but also accelerate the sulfur autotrophic denitrification electron donor sulfide (S 2- ), sulfite (SO3 2- )) can also capture hydrogen sulfide to form iron sulfide enriched in the filler, thereby alleviating the corrosion of hydrogen sulfide to water treatment related equipment and pipelines. The preparation raw materials of the present invention include surfactants, which can reduce the surface tension between particles and liquid during the preparation process, prevent the agglomeration of filler raw material particles, and ensure the uniformity of filler components; amylose is used as an adhesive, and can also promote the formation of sulfur autotrophic bacteria.

[0022] The preparation and operation process of the filler of the present invention is simple, without complex and harsh process links, the raw materials are easy to obtain, the price is low, and no toxic substances are produced. The sulfur autotrophic denitrification biological filler prepared by the present invention has high material porosity, strong water permeability, and light material. The application method is flexible and simple, and is not restricted by the scene and water pollution conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is a diagram of the preparation process of the sulfur autotrophic denitrification biological filler in an embodiment of the present invention;

[0025] Figure 2 is the NO3 in the effluent of bioreactors R1, R2, and R3 at each stage in the embodiment of the present invention. - -N concentration curve;

[0026] Figure 3 The bioreactors R1, R2, and R3 in each stage of the embodiment of the present invention are shown in FIG. - -N removal rate curve;

[0027] Figure 4 1 is a curve diagram of pH value changes in bioreactors R1, R2, and R3 at various stages in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] The present invention provides a method for preparing a sulfur autotrophic denitrification biological filler, comprising the following steps:

[0029] mixing sulfur powder, iron powder, surfactant, activated carbon, amylose and water and heating them to obtain a molten fluid;

[0030] The molten fluid and alkali are mixed to carry out a disproportionation reaction to obtain a thickened material;

[0031] The thickened material is molded to obtain sulfur autotrophic denitrification biological filler.

[0032] In the present invention, unless otherwise specified, the materials and equipment used are commercially available products in the art.

[0033] The invention mixes and heats sulfur powder, iron powder, surfactant, activated carbon, straight-chain starch and water to obtain a molten fluid.

[0034] In the present invention, the sulfur content of the sulfur powder (sulfur powder) is preferably greater than 95%, and the particle size is preferably 150-250 meshes, specifically 200 meshes. The sulfur powder is the source of electron donors for sulfur autotrophic denitrifying bacteria.

[0035] In the present invention, the iron powder is a single iron powder, and the particle size of the iron powder is preferably 100-250 meshes, specifically 150 meshes. The iron powder can enhance sulfur disproportionation, and can also capture hydrogen sulfide to form ferrous sulfide enriched in the filler, thereby alleviating the corrosion of hydrogen sulfide to water treatment equipment and pipelines.

[0036] In the present invention, the mass ratio of the sulfur powder to the iron powder is preferably (60-80):(5-10), specifically 8:1, 7:1 or 14:1. In the present invention, the mass ratio of sulfur powder to iron powder needs to be precisely controlled within a specific range. If the iron content is too high, due to the frequent side reactions involving iron, the generated iron ions and other substances are very likely to have a negative impact on the growth and activity of microorganisms, and will also cause the pH of the system to change; on the contrary, if the iron content is too low, the mechanical strength of the filler will be weakened, making the filler easy to break during long-term use, thereby shortening the service life of the filler.

[0037] In the present invention, the surfactant is preferably an anionic surfactant, and the anionic surfactant preferably includes sodium alkylbenzene sulfonate and / or sodium fatty acid ester sulfonate. The anionic surfactant can reduce the surface tension between the particles and the liquid, play a dispersing role, prevent the filler raw material particles from agglomerating, and ensure the uniformity of the filler composition.

[0038] In the present invention, the particle size of the activated carbon is preferably 200-400 meshes, and specifically 300 meshes. The activated carbon is an adsorbent.

[0039] In the present invention, the amylose is used as an adhesive and can promote the biofilm formation of sulfur autotrophic bacteria.

[0040] In the present invention, the mass ratio of the sulfur powder, iron powder, surfactant, activated carbon and amylose is preferably (60-80):(5-10):(2-5):(5-10):(2-5), specifically 80:10:2:5:2, 70:10:2:5:2 or 70:5:2:5:2.

[0041] In the present invention, the mass ratio of the sulfur powder to water is preferably (6-8):(5-8), specifically 7:5 or 8:5.

[0042] In the present invention, the heating temperature is preferably 120-180° C., the insulation time is preferably 10-40 min, specifically 30 min, the heating is preferably accompanied by stirring, and the stirring speed is preferably 80-200 rpm, specifically 120 rpm.

[0043] In the present invention, the temperature of the molten fluid is preferably 120-180° C., and the molten fluid is a mixture of raw material components.

[0044] After obtaining the molten fluid, the present invention mixes the molten fluid with alkali to carry out a disproportionation reaction to obtain a thickened material.

[0045] In the present invention, the alkali is preferably a hot alkali solution, the hot alkali solution is preferably a sodium hydroxide solution, the concentration of the sodium hydroxide solution is preferably 2-6 mol / L, specifically 2, 3, 4, 5 or 6 mol / L, the pH value is preferably 12-14, specifically 12, 13 or 14; the temperature is preferably 50-100° C., specifically 50, 60, 70, 80, 90 or 100° C. In the hot alkali solution used in the present invention, the movement speed of ions is fast and the chemical activity is strong.

[0046] In the present invention, the temperature of the disproportionation reaction is preferably 130-170°C, specifically 150°C, the time is preferably 10-40 min, specifically 30 min; the pH value is preferably 6-12, specifically 7-8; the disproportionation reaction is preferably carried out under stirring conditions, and the stirring speed is preferably 80-200 rpm, specifically 120 rpm. Taking sodium hydroxide as an example, the disproportionation reaction process undergoes the following reaction:

[0047] 3S+6NaOH→2Na2S+Na2SO3+3H2O

[0048] The disproportionation reaction conditions of the present invention are helpful to stabilize the intermediate state or reactants, and promote the reorganization and transformation of sulfur. In the disproportionation reaction process, elemental iron has a dual strengthening effect on sulfur disproportionation: on the one hand, it acts as a catalyst to adsorb sulfur molecules and enhance the reactivity of sulfur molecules to prepare for subsequent denitrification; on the other hand, it participates in the reaction (Fe+S→FeS) to generate ferrous sulfide (FeS), enhances the electron transfer of the reaction system, and accelerates the sulfur autotrophic denitrification electron donor sulfide (S 2- ), sulfite (SO3 2- )’s formation.

[0049] In the present invention, taking the hot alkali solution as sodium hydroxide solution as an example, the main components of the thickening material include S 0 , Na2S, Na2SO3, Fe, FeS, activated carbon, etc.

[0050] After obtaining the thickened material, the present invention shapes the thickened material to obtain the sulfur autotrophic denitrification biological filler.

[0051] In the present invention, the molding preferably includes granulation and drying. The present invention has no special requirements for the granulation method. The particle size of the spherical particles obtained by the granulation is preferably 3 to 8 mm. Within this particle size range, the sulfur autotrophic denitrification biological filler can exhibit excellent physical properties, provide suitable conditions for the attachment and growth of microorganisms, thereby ensuring its good biological performance, which is conducive to realizing an efficient sulfur autotrophic denitrification process.

[0052] In the present invention, the drying is preferably hot air drying, the temperature of the hot air drying is preferably 80-100° C., the time is preferably 5-10 hours, specifically 8 hours; the drying can remove moisture from the spherical particles.

[0053] The present invention also provides a sulfur autotrophic denitrification biological filler obtained by the preparation method described in the above technical solution. The sulfur autotrophic denitrification biological filler contains S 2- and SO3 2- .

[0054] The present invention also provides the use of the sulfur autotrophic denitrification biological filler described in the above technical solution in sewage denitrification treatment.

[0055] In the present invention, the sewage preferably includes groundwater containing nitrate nitrogen, industrial wastewater or aquaculture wastewater.

[0056] In the present invention, the filling rate of the sulfur autotrophic denitrification biological filler in the sewage denitrification treatment is preferably 60% to 80%, and specifically can be 70%.

[0057] In the present invention, the parameters of the wastewater denitrification treatment include: the wastewater retention time is preferably 6 hours, the room temperature, and the pH value is preferably 8.

[0058] The sulfur autotrophic denitrification biological filler of the present invention is prepared with sulfur powder as the main matrix, iron powder as a catalyst, and auxiliary agents such as surfactants, activated carbon, and amylose. After the components are mixed, they are melted into a liquid state, and then a hot alkaline solution is added to induce the disproportionation of elemental sulfur. In the reaction process, elemental iron has a dual role in strengthening sulfur disproportionation. On the one hand, it acts as a catalyst to adsorb sulfur molecules and enhance the reactivity of sulfur molecules to prepare for the follow-up; on the other hand, it participates in the reaction to generate ferrous sulfide (FeS), enhance the electron transfer of the reaction system, and accelerate the sulfur autotrophic denitrification electron donor sulfide (S 2- ), sulfite (SO3 2- The preparation method of the present invention combines physical mixing with chemical conversion, which not only improves the bioavailability of sulfur, but also provides more active electron donors for the subsequent sulfur autotrophic denitrification process, thereby achieving high-efficiency, low-cost, and deep denitrification.

[0059] In order to further illustrate the present invention, the sulfur autotrophic denitrification biological filler provided by the present invention and its preparation method and application are described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the scope of protection of the present invention.

[0060] In an embodiment of the present invention, the components of the filler include: sulfur powder (sulfur powder), elemental iron powder, sodium alkylbenzene sulfonate, activated carbon, and amylose, and the proportions of each component are all weight proportions; the sulfur content of the sulfur powder exceeds 95%, and the particle size is 200 mesh; the iron powder particle size is 150 mesh; and the activated carbon particle size is 300 mesh.

[0061] Follow the steps below Figure 1 The preparation process diagram shown is used to prepare sulfur autotrophic denitrification biological filler:

[0062] Example 1

[0063] The method for preparing sulfur autotrophic denitrification biological filler comprises the following steps:

[0064] Step 1: Add 80 parts of sulfur powder, 10 parts of elemental iron powder, 2 parts of sodium alkylbenzene sulfonate, 5 parts of activated carbon, 2 parts of amylose, and 50 parts of deionized water into the reactor, start the stirring device and heat up at the same time, the speed is 120 rpm, stir for 30 minutes, and the temperature in the reactor is raised and maintained at 120°C until all components are mixed and melted into a fluid.

[0065] Step 2: Inject a hot sodium hydroxide solution with a pH value of 13, a temperature of 80°C, and a concentration of 3 mol / L into the reactor, adjust the pH of the reactor to 8, the temperature to 150°C, the rotation speed to 120 rpm, and stir for 30 minutes to allow the material to fully contact and react with the hot alkaline solution to finally obtain a thickened material.

[0066] Step 3: Granulate the obtained thickened material to prepare spherical filler particles with a particle size of 3 mm; dry them with hot air at 80° C. for 8 h, and obtain spherical composite fillers (sulfur autotrophic denitrification biological fillers) after cooling.

[0067] Example 2

[0068] The method for preparing sulfur autotrophic denitrification biological filler comprises the following steps:

[0069] Step 1: Add 70 parts of sulfur powder, 10 parts of elemental iron powder, 2 parts of sodium alkylbenzene sulfonate, 5 parts of activated carbon, 2 parts of amylose, and 50 parts of deionized water into the reactor, start the stirring device and heat up at the same time, the speed is 120 rpm, stir for 30 minutes, and the temperature in the reactor is raised and maintained at 120°C until all components are mixed and melted into a fluid.

[0070] Step 2: Inject a hot sodium hydroxide solution with a pH value of 13, a temperature of 80°C, and a concentration of 3 mol / L into the reactor, adjust the pH of the reactor to 8, the temperature to 150°C, the rotation speed to 120 rpm, and stir for 30 minutes to allow the material to fully contact and react with the hot alkaline solution to finally obtain a thickened material.

[0071] Step 3: Granulate the obtained thickened material to prepare spherical filler particles with a particle size of 3 mm; dry them with hot air at 80° C. for 8 h, and obtain spherical composite fillers after cooling.

[0072] Example 3

[0073] The method for preparing sulfur autotrophic denitrification biological filler comprises the following steps:

[0074] Step 1: Add 70 parts of sulfur powder, 5 parts of elemental iron powder, 2 parts of sodium alkylbenzene sulfonate, 5 parts of activated carbon, 2 parts of amylose, and 50 parts of deionized water into the reactor, start the stirring device and heat up at the same time, the speed is 120 rpm, stir for 30 minutes, and the temperature in the reactor is raised and maintained at 120°C until all components are mixed and melted into a fluid.

[0075] Step 2: Inject a hot sodium hydroxide solution with a pH value of 13, a temperature of 80°C, and a concentration of 3 mol / L into the reactor, adjust the pH of the reactor to 8, the temperature to 150°C, the rotation speed to 120 rpm, and stir for 30 minutes to allow the material to fully contact and react with the hot alkaline solution to finally obtain a thickened material.

[0076] Step 3: Granulate the obtained thickened material to prepare spherical filler particles with a particle size of 3 mm; dry them with hot air at 80° C. for 8 h, and obtain spherical composite fillers after cooling.

[0077] The fillers prepared in the above examples were applied in sewage treatment. The fillers prepared in Examples 1, 2, and 3 were placed in a 1L small upflow anaerobic reactor, with a filler filling rate of 70%. The biofilter reactor formed in Example 1 was recorded as R1, the biofilter reactor formed in Example 2 was recorded as R2, and the biofilter reactor formed in Example 3 was recorded as R3. Under the same other conditions (temperature 30°C, pH value 8, HRT 6h), a continuous flow experiment was carried out to verify its denitrification effect.

[0078] The operating parameters such as the influent nitrate nitrogen concentration are shown in Table 1. The hydraulic retention time (HRT) is set to 6 h, the temperature is room temperature, and the pH value is controlled at 8. The specific operating steps of the experiment are as follows:

[0079] (1) Before the denitrification filter is officially put into operation, the biofilter needs to be treated for biofilm formation. The activated sludge from the anaerobic tank of a sewage plant is inoculated into three biofilters. The biofilm formation sludge is inoculated once every 5 days. After 3 cycles, the water quality indicators (nitrate nitrogen concentration) are monitored every day. When the water quality indicators are stable for one consecutive cycle (the nitrate nitrogen in the effluent is stable, and the nitrate nitrogen removal rate is greater than 60%), the biofilm formation is considered successful.

[0080] The filler of the present invention forms a biofilm successfully between 20 and 25 days, which is superior to the composite filler formed by sulfur particles and pyrite (forming biofilm time 30 days) and has a short forming biofilm time.

[0081] (2) After the biofilter was formed, simulated wastewater was prepared with laboratory tap water, potassium nitrate (KNO3) was used as the only nitrogen source, and the nitrogen load was increased in a gradient of 100 mg / L. The specific water quality of the experimental inlet water at each stage is shown in Table 1. Water samples were taken from the effluent pool once a day and various water quality indicators were tested.

[0082] Table 1 Specific water quality of each stage

[0083]

[0084]

[0085] Figures 2 to 4 The treatment effect diagram of the simulated wastewater by reactors R1, R2 and R3 is shown in Figure 2. Figure 2 NO3 in the effluent of bioreactors R1, R2, and R3 at each stage - -N concentration curve; Figure 3 The bioreactors R1, R2, and R3 react with NO3 at each stage. - -N removal rate curve; Figure 4 The following is the curve of pH value change of the effluent from bioreactors R1, R2 and R3 at each stage; it can be found that:

[0086] (1) As the influent nitrate nitrogen concentration increased, the denitrification effects of the three reactors gradually deteriorated, especially in the fifth stage, when the effluent nitrate nitrogen concentrations of the three reactors exceeded 50 mg / L, with the effluent nitrate nitrogen of R1 at about 85 mg / L, the effluent nitrate nitrogen of R2 at about 55 mg / L, and the effluent nitrate nitrogen of R3 at about 70 mg / L;

[0087] (2) In the first, second, and third stages, although the nitrate nitrogen treatment effects of the R2 and R3 reactors were similar, with the increase of influent NO3 - -N concentration increased stepwise to 400 mg / L and above, the denitrification performance of the R3 reactor became worse and worse compared with the R2 with relatively higher iron content, and the effluent pH value became lower and lower;

[0088] (3) During the entire reaction process, the effect of reactor R2 with the highest relative content of elemental iron remained stable, with a nitrate removal rate of more than 90%. In the fifth stage, under high nitrate nitrogen load, the nitrate nitrogen removal rate was also close to 90%, and the pH stability of the system was the best.

[0089] The long-term stable treatment capacity of the three reactors shows that the presence of elemental sulfur in the filler enables the sulfur autotrophic denitrification reaction to always run smoothly. The presence and relative content of elemental iron play a very important role in the long-term denitrification effect of the reactor. Therefore, the biological filler provided by the present invention can achieve a relatively excellent denitrification effect in the treatment of nitrogen-containing wastewater and has good application value.

[0090] Comparative Example 1

[0091] In this comparative example, no elemental iron powder is added in Step 1, and Step 2 is not performed. The molten fluid is directly granulated. The remaining components, preparation methods, and application methods are the same as those in Example 1.

[0092] The obtained filler is filled into the denitrification bioreactor. After stable operation, the sulfur autotrophic denitrification bioreactor starts from the second stage and the influent NO3 - When -N is greater than 200 mg / L, the nitrate nitrogen in the reactor effluent is greater than 80 mg / L, and the nitrate nitrogen removal rate is below 50%. The filler has a poor effect on denitrification and has no high application value.

[0093] The sulfur autotrophic denitrification biological filler of the present invention has the advantages of large specific surface area, good biofilm performance, not easy to be blocked, low cost, etc., can provide a good growth environment for sulfur autotrophic denitrifying bacteria, and improve the efficiency of sulfur autotrophic denitrification. At the same time, the preparation method of the biological filler is simple and easy, low cost, and convenient for large-scale production and application. In addition, the biological filler also has good stability and durability, and can maintain good denitrification performance during long-term operation.

[0094] Although the above-mentioned embodiments have made a detailed description of the present invention, they are only some embodiments of the present invention, rather than all embodiments. People can also obtain other embodiments based on the embodiments of the present invention without creative work, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a sulfur autotrophic denitrification biological filler, characterized in that: The following steps are involved: mixing sulfur powder, iron powder, surfactant, activated carbon, amylose and water and heating them to obtain a molten fluid; The molten fluid and alkali are mixed to carry out a disproportionation reaction to obtain a thickened material; The thickened material is molded to obtain a sulfur autotrophic denitrification biological filler; the sulfur autotrophic denitrification biological filler contains S2 - and SO3 2- .

2. The preparation method according to claim 1, characterized in that: The mass ratio of the sulfur powder to the iron powder is (60-80):(5-10).

3. The preparation method according to claim 1 or 2, characterized in that: The particle size of the iron powder is 100-250 meshes.

4. The preparation method according to claim 1, characterized in that: The surfactant is an anionic surfactant, and the anionic surfactant includes sodium alkylbenzene sulfonate and / or sodium fatty acid ester sulfonate.

5. The preparation method according to claim 1, characterized in that: The mass ratio of the sulfur powder, iron powder, surfactant, activated carbon and amylose is (60-80):(5-10):(2-5):(5-10):(2-5).

6. The preparation method according to claim 1 or 5, characterized in that: The heating temperature is 120-180° C., the heat preservation time is 10-40 min, the heating is accompanied by stirring, and the stirring speed is 80-200 rpm.

7. The preparation method according to claim 1, characterized in that: The alkali is a hot alkali solution, the hot alkali solution is a sodium hydroxide solution, the concentration of the sodium hydroxide solution is 2-6 mol / L, the pH value is 12-14, and the temperature is 50-100°C.

8. The preparation method according to claim 1 or 7, characterized in that: The temperature of the disproportionation reaction is 130-170° C., and the time is 10-40 minutes.

9. The sulfur autotrophic denitrification biological filler obtained by the preparation method according to any one of claims 1 to 8, characterized in that: The sulfur autotrophic denitrification biological filler contains S2 - and SO3 2- .

10. Use of the sulfur autotrophic denitrification biological filler according to claim 9 in wastewater denitrification treatment.

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