Wastewater treatment method based on sulfur autotrophy and additive-free carbon source

Abstract

The invention discloses a wastewater treatment method based on sulfur autotrophy and an additive-free carbon source, relates to the technical field of sulfur autotrophy, and adopts an upflow reactor, and a filler area is filled with a layered wastewater treatment filter material. The filter material takes lignocellulose nanofibers as a base layer, and a functional layer consists of a sulfur-based composite filter material and cuprous oxide / ferrous oxide heterojunction and is prepared by loading sulfur autotrophic denitrifying bacteria liquid. According to the method, no organic carbon source needs to be added, synchronous nitrogen and phosphorus removal of the low-carbon-nitrogen-ratio wastewater is achieved through the adsorption-catalysis-biological synergistic effect, the raw materials are derived from industrial and agricultural waste, the environment compatibility is good, and the method is suitable for wastewater treatment of municipal administration, breeding and the like.

Description

Technical Field

[0001] This invention relates to the field of sulfur autotrophic technology, specifically a wastewater treatment method based on sulfur autotrophic technology without the addition of a carbon source. Background Technology

[0002] Current low C / N ratio wastewater treatment faces numerous challenges: traditional biological denitrification technologies rely on organic carbon sources, and adding additional carbon increases operating costs and sludge production; existing sulfur autotrophic denitrification technologies suffer from low electron transfer efficiency, nitrite accumulation, and poor phosphorus removal, and unreasonable filter media structures lead to impeded mass transfer and insufficient stability. Furthermore, single materials or microbial systems struggle to balance denitrification efficiency and selectivity.

[0003] Therefore, there is an urgent need to develop carbon-free, highly efficient, synergistic, stable, and reliable wastewater treatment technologies. Summary of the Invention

[0004] The purpose of this invention is to provide a wastewater treatment method based on sulfur autotrophy without added carbon source, so as to solve the problems raised in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A wastewater treatment method based on sulfur autotrophy without added carbon source, the wastewater treatment method includes the following steps: the wastewater processor body used in the wastewater treatment is an upflow processor, the wastewater processor body is divided into an inlet zone, a packing zone and an outlet zone from bottom to top, the inlet zone is connected to the inlet system, the outlet zone is connected to the outlet system, and the packing material in the packing zone is wastewater treatment filter media. Furthermore, the wastewater filter material is prepared by coating a functional layer slurry onto the surface of a lignocellulose nanofiber base layer, drying it, and then immersing it in a sulfur-autotrophic denitrifying bacteria solution. Furthermore, the functional layer slurry is prepared by adding sulfur-based composite filter media and cuprous oxide / ferrous oxide heterojunction powder to deionized water.

[0006] Furthermore, the preparation method of the lignocellulose nanofiber base layer includes the following steps: placing the treated agricultural waste in a 10-20wt% hydrogen peroxide solution, heating to 30-50℃ for oxidative treatment for 2-4 hours, washing with deionized water until the pH of the washing solution is neutral, then soaking in a 70-75% ethanol solution for purification, vacuum drying at 60-80℃, pulverizing to 60-100 mesh, and homogenizing under high pressure at 50-100MPa to obtain lignocellulose nanofibers; adding the lignocellulose nanofibers to deionized water, stirring evenly, pouring into a mold, and drying at 80-100℃ to obtain the lignocellulose nanofiber base layer.

[0007] Furthermore, in the preparation process of the lignin cellulose nanofibers, the agricultural waste includes either wheat straw or sugarcane bagasse; in the preparation process of the lignin cellulose nanofiber base layer, the mass ratio of lignin cellulose nanofibers to deionized water is 1:(3-5).

[0008] Furthermore, the preparation method of the sulfur-based composite filter material includes the following steps: heating industrial waste to 600-800℃, calcining for 2-3 hours, and pulverizing to 100-200 mesh to obtain elemental sulfur powder; Ferric nitrate nonahydrate was added to ethylene glycol to obtain a ferric nitrate nonahydrate solution. The ferric nitrate nonahydrate solution was placed in a high-pressure reactor and heated to 120-150℃ for 2-4 hours. After centrifugation, the precipitate was washed with deionized water and dried under vacuum at 60-80℃ to obtain ferrous oxide powder. The above elemental sulfur powder and ferrous oxide powder were added to deionized water and heated to 50-70℃ with stirring for 1-2 hours. After centrifugation, the mixture was dried under vacuum at 60-80℃ to obtain sulfur-based composite filter media.

[0009] Furthermore, the industrial waste includes any one of the following: desulfurization tailings from paper mills and sludge from mining wastewater treatment. In the preparation of sulfur-based composite filter media, the concentration of ferric nitrate nonahydrate solution is 20-50 mmol / L; the mass ratio of elemental sulfur powder to ferrous oxide powder is (3-5):1, and the solid-liquid ratio is 1:(10-20).

[0010] Furthermore, the preparation method of the cuprous oxide / ferrous oxide heterojunction powder includes the following steps: after pretreating the foamed copper, it is immersed in a mixed aqueous solution of ammonium persulfate and sodium hydroxide, heated to 25-30℃ and reacted for 3-5 minutes to obtain copper hydroxide-loaded copper foam; the copper hydroxide-loaded copper foam is placed in a tube furnace, heated in stages, and cooled to obtain copper oxide-loaded copper foam. The copper oxide-loaded copper foam was immersed in a solution of ferric nitrate nonahydrate in ethylene glycol and placed in a high-pressure reactor at 120-130°C for 2-3 hours. After cooling, it was removed, washed with deionized water, vacuum dried at 60-80°C, and electrochemically activated to obtain cuprous oxide / ferrous oxide heterojunctions. The mixture was then peeled off and pulverized into 200-300 mesh powder for later use.

[0011] Furthermore, in the preparation process of the copper oxide-supported copper foam, the concentration of ammonium persulfate aqueous solution is 6.8-7 g / L, and the concentration of sodium hydroxide aqueous solution is 150-170 g / L; the segmented heating process involves raising the temperature to 150-155℃ at a heating rate of 5-6℃ and holding for 3-4 hours, then raising it to 200-205℃ and holding for 3-4 hours; in the preparation process of the cuprous oxide / ferrous oxide heterojunction, the concentration of ferric nitrate nonahydrate ethylene glycol solution is 20-30 mmol / L, the voltage range of the electrochemical activation is +0.3V to -1.0V, the scan rate is 45-50 mV / s, and the number of cycles is 45-50.

[0012] Furthermore, the method for preparing the sulfur autotrophic denitrifying bacterial solution includes the following steps: inoculating the sulfur autotrophic denitrifying functional bacterial group into the sulfur autotrophic denitrification medium, and anaerobically culturing it for 48-72 hours at pH 6.5-7.0 and 25-30℃; the sulfur autotrophic denitrifying functional bacterial group includes any one of sulfur-oxidizing bacteria and sulfur-driven denitrifying bacteria; the components in the sulfur autotrophic denitrification medium, by mass fraction, include: 5-10g of elemental sulfur powder, 1-3g of sodium nitrate, 0.5-1g of potassium dihydrogen phosphate, 0.2-0.5g of magnesium sulfate, 0.1-0.3g of calcium chloride, 1-3mL of trace element solution, and 1000g of deionized water; the trace element solution consists of 0.01g of ferrous sulfate, 0.02g of manganese sulfate, 0.005g of copper sulfate, 0.005g of zinc sulfate, and 100mL of deionized water.

[0013] Furthermore, the preparation method of the wastewater filter material includes the following steps: mixing sulfur-based composite filter material and cuprous oxide / ferrous oxide heterojunction powder evenly, adding it to deionized water, and stirring at 40-60℃ for 1-2 hours to obtain functional layer slurry; The functional layer slurry is coated onto the surface of the lignocellulose nanofiber base layer and dried at 100-120℃ for 2-3 hours to obtain a layered substrate. The layered substrate is immersed in sulfur-autotrophic denitrifying bacteria solution and anaerobically soaked at 25-30℃ for 12-24 hours. After rinsing the surface with deionized water, wastewater filter media is obtained.

[0014] Furthermore, in the preparation process of the functional layer slurry, the mass ratio of sulfur-based composite filter material to cuprous oxide / ferrous oxide heterojunction powder is (5-8):1, and the solid-liquid ratio is 1:(8-12). In the preparation of wastewater filter media, the volume ratio of sulfur autotrophic denitrifying bacteria liquid to layered substrate is (5-10):1. In the wastewater filter media, the thickness ratio of the lignocellulose nanofiber base layer to the functional layer slurry is (2-5):(1-3).

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In this invention, lignocellulose nanofibers, after oxidation-hydrogenation and high-pressure homogenization, form a high specific surface area and porous structure. The hydroxyl and carboxyl functional groups on their surface achieve targeted enrichment of nitrates and phosphates in wastewater through physical adsorption and electrostatic interactions. Simultaneously, the fiber network structure provides mechanical support for the functional layer, preventing the loss of functional components. Furthermore, the natural biomass properties of lignocellulose nanofibers exhibit good biocompatibility, and their porous structure can construct microbial attachment sites, providing a stable microenvironment for subsequent sulfur-autotrophic bacterial communities and reducing bacterial loss due to hydraulic shock. This allows for the adsorption and enrichment of substrates during the pretreatment stage, increasing the pollutant concentration in the functional layer area and enhancing subsequent catalytic and biological metabolic efficiency.

[0016] 2. In this invention, elemental sulfur serves as the core electron donor for sulfur autotrophic denitrification. It is oxidized to sulfate by sulfur-oxidizing bacteria, releasing electrons in the process to provide energy for nitrate reduction. Ferrous oxide accelerates the transfer of electrons released from elemental sulfur oxidation to heterojunctions and microorganisms, overcoming the bottleneck of slow electron transfer in single-sulfur autotrophic processes. Simultaneously, it possesses water-splitting properties, allowing ferrous oxide to moderately catalyze water splitting to produce active hydrogen, precisely matching the hydrogenation requirements of nitrate reduction and avoiding excessive active hydrogen competing with active nitrogen for adsorption sites. This continuous provision of electron donors supports the continuous metabolism of sulfur autotrophic bacteria, enabling stable nitrate reduction under conditions without organic carbon sources.

[0017] 3. After electrochemical activation, the heterojunction of the present invention undergoes local charge redistribution at the Cu2O and FeO interface, forming a "Cu-ON-Fe" directional adsorption configuration. This enriches and polarizes nitrate molecules at the interface, lowers the energy barrier for NO bond breaking, and the catalytic active sites of the heterojunction preferentially promote the reduction pathway of nitrate to nitrogen, suppressing the ammoniation side reaction and greatly improving nitrogen selectivity.

[0018] 4. In summary, the lignocellulose nanofiber substrate, with its high specific surface area and surface functional groups, adsorbs and enriches nitrates and phosphates in wastewater, providing a high concentration of substrate for the reaction; in the sulfur-based composite filter media, elemental sulfur acts as the core electron donor for sulfur autotrophic denitrification, and ferrous oxide, through Fe... 2+ / Fe 3+ Redox cycles accelerate electron transfer; electrochemical activation of the cuprous oxide / ferrous oxide heterojunction leads to interfacial charge redistribution, directional adsorption of nitrates, and reduction of the NO bond breaking energy barrier; sulfur autotrophic bacteria synergistically construct a coupling of sulfur oxidation and nitrate reduction metabolism with the material; layered structure achieves functional zoning, and the upflow reactor enhances mass transfer, avoiding component interference and filter media clogging. During wastewater treatment, no organic carbon source is required, significantly reducing operating costs. Raw materials are derived from agricultural and industrial waste, ensuring good environmental compatibility; optimized hydraulic performance results in low head loss, making it suitable for low C / N ratio municipal wastewater, aquaculture wastewater, and other scenarios, with a wide range of applications. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: A wastewater treatment method based on sulfur autotrophy without added carbon source, comprising the following steps: the wastewater processor body used in the wastewater treatment is an upflow processor, and the wastewater processor body consists of an inlet zone, a packing zone and an outlet zone from bottom to top. The inlet zone is connected to the inlet system, and the outlet zone is connected to the outlet system. The packing material in the packing zone is wastewater treatment filter media. The inlet COD is 180 mg / L, the pH is 6.8, the hydraulic retention time is 6 h, and the reaction temperature is 25 °C.

[0021] The preparation method of lignocellulose nanofiber base layer includes the following steps: placing treated wheat straw in a 15wt% hydrogen peroxide solution, heating to 35℃ for oxidative treatment for 3 hours, washing with deionized water until the pH of the washing solution is neutral, then soaking in a 70% ethanol solution for purification, vacuum drying at 60℃, pulverizing to 80 mesh, and homogenizing under high pressure at 80MPa to obtain lignocellulose nanofibers; adding the lignocellulose nanofibers to deionized water, stirring evenly, pouring into a mold, and drying at 90℃ to obtain the lignocellulose nanofiber base layer.

[0022] In the preparation of the lignocellulose nanofiber base layer, the mass ratio of lignocellulose nanofiber to deionized water is 1:4.

[0023] The preparation method of sulfur-based composite filter material includes the following steps: heating the desulfurization tailings of a paper mill to 700℃, calcining for 2.5 hours, and pulverizing to 150 mesh to obtain elemental sulfur powder; 25 mmol / L ferric nitrate nonahydrate was added to ethylene glycol to obtain a ferric nitrate nonahydrate solution. The ferric nitrate nonahydrate solution was placed in a high-pressure reactor, heated to 130°C and reacted for 3 h. After centrifugation, the precipitate was washed with deionized water and dried under vacuum at 60°C to obtain ferrous oxide powder. The above elemental sulfur powder and ferrous oxide powder were added to deionized water, heated to 60°C and stirred for 1.5 h. After centrifugation, the mixture was dried under vacuum at 60°C to obtain sulfur-based composite filter media.

[0024] The mass ratio of elemental sulfur powder to ferrous oxide powder is 4:1, and the solid-liquid ratio is 1:15.

[0025] A method for preparing cuprous oxide / ferrous oxide heterojunction powder includes the following steps: copper foam is pretreated by ultrasonically cleaning it sequentially in ethanol and 1 mol / L sulfuric acid solution for 10 minutes each, then immersed in a mixed aqueous solution of 6.9 g / L ammonium persulfate and 160 g / L sodium hydroxide, and heated to 25°C for 3 minutes to obtain copper hydroxide-loaded copper foam; the copper hydroxide-loaded copper foam is placed in a tube furnace, heated to 150°C at a rate of 5°C and held for 3 hours, then heated to 200°C and held for 3 hours, and cooled to obtain copper oxide-loaded copper foam; Copper oxide-supported copper foam was immersed in a 25 mmol / L solution of ferric nitrate nonahydrate in ethylene glycol and reacted in a high-pressure reactor at 120°C for 2 hours. After cooling, the foam was removed, washed with deionized water, and dried under vacuum at 60°C. Electrochemical activation was performed with a voltage range of +0.3V to -1.0V, a scan rate of 50mV / s, and 50 cycles to obtain cuprous oxide / ferrous oxide heterojunctions. The mixture was then exfoliated and pulverized into 200-mesh powder for later use.

[0026] A method for preparing sulfur autotrophic denitrifying bacterial solution includes the following steps: sulfur-oxidizing bacteria are inoculated into sulfur autotrophic denitrification medium and cultured anaerobicly at pH 6.8 and 25℃ for 60 hours; the components of the sulfur autotrophic denitrification medium, by mass fraction, include: 8g of elemental sulfur powder, 2g of sodium nitrate, 0.8g of potassium dihydrogen phosphate, 0.4g of magnesium sulfate, 0.2g of calcium chloride, 2mL of trace element solution, and 1000g of deionized water; the trace element solution consists of 0.01g of ferrous sulfate, 0.02g of manganese sulfate, 0.005g of copper sulfate, 0.005g of zinc sulfate, and 100mL of deionized water.

[0027] The preparation method of wastewater filter media includes the following steps: mixing sulfur-based composite filter media and cuprous oxide / ferrous oxide heterojunction powder evenly, adding them to deionized water, heating to 40°C and stirring for 1 hour to obtain functional layer slurry; The functional layer slurry was coated onto the surface of the lignocellulose nanofiber base layer and dried at 100℃ for 2 hours to obtain a layered substrate. The layered substrate was immersed in sulfur-autotrophic denitrifying bacteria solution and anaerobically soaked at 25°C for 12 hours. After rinsing the surface with deionized water, wastewater filter media was obtained.

[0028] In the preparation of the functional layer slurry, the mass ratio of sulfur-based composite filter material to cuprous oxide / ferrous oxide heterojunction powder is 6:1, and the solid-liquid ratio is 1:10. In the preparation of wastewater filter media, the volume ratio of sulfur autotrophic denitrifying bacteria liquid to layered substrate is 7:1. In the wastewater filter media, the thickness ratio of the lignocellulose nanofiber base layer to the functional layer slurry is 5:3.

[0029] Example 2: A wastewater treatment method based on sulfur autotrophy without added carbon source, comprising the following steps: a wastewater filter material preparation method, comprising the following steps: mixing sulfur-based composite filter material and cuprous oxide / ferrous oxide heterojunction powder evenly, adding to deionized water, adding to heat to 40°C and stirring for 1 hour to obtain functional layer slurry; The functional layer slurry was coated onto the surface of the lignocellulose nanofiber base layer and dried at 100℃ for 2 hours to obtain a layered substrate. The layered substrate was immersed in sulfur-autotrophic denitrifying bacteria solution and anaerobically soaked at 25°C for 12 hours. After rinsing the surface with deionized water, wastewater filter media was obtained.

[0030] In the preparation of the functional layer slurry, the mass ratio of sulfur-based composite filter media to cuprous oxide / ferrous oxide heterojunction powder is 5:1, and the solid-liquid ratio is 1:10. In the preparation of wastewater filter media, the volume ratio of sulfur autotrophic denitrifying bacteria liquid to layered substrate is 7:1. In the wastewater filter media, the thickness ratio of the lignocellulose nanofiber base layer to the functional layer slurry is 5:3. The remaining steps are the same as in Example 1.

[0031] Example 3: A wastewater treatment method based on sulfur autotrophy without added carbon source, comprising the following steps: a wastewater filter material preparation method, comprising the following steps: mixing sulfur-based composite filter material and cuprous oxide / ferrous oxide heterojunction powder evenly, adding to deionized water, adding to heat to 40°C and stirring for 1 hour to obtain functional layer slurry; The functional layer slurry was coated onto the surface of the lignocellulose nanofiber base layer and dried at 100℃ for 2 hours to obtain a layered substrate. The layered substrate was immersed in sulfur-autotrophic denitrifying bacteria solution and anaerobically soaked at 25°C for 12 hours. After rinsing the surface with deionized water, wastewater filter media was obtained.

[0032] In the preparation of the functional layer slurry, the mass ratio of sulfur-based composite filter material to cuprous oxide / ferrous oxide heterojunction powder is 8:1, and the solid-liquid ratio is 1:10. In the preparation of wastewater filter media, the volume ratio of sulfur autotrophic denitrifying bacteria liquid to layered substrate is 7:1. In the wastewater filter media, the thickness ratio of the lignocellulose nanofiber base layer to the functional layer slurry is 5:3. The remaining steps are the same as in Example 1.

[0033] Comparative Example 1: A wastewater treatment method based on sulfur autotrophy without added carbon source, comprising the following steps: a wastewater filter media preparation method comprising the following steps: adding sulfur-based composite filter media to deionized water, heating to 40°C and stirring for 1 hour to obtain functional layer slurry; The functional layer slurry was coated onto the surface of the lignocellulose nanofiber base layer and dried at 100℃ for 2 hours to obtain a layered substrate. The layered substrate was immersed in sulfur-autotrophic denitrifying bacteria solution and anaerobically soaked at 25°C for 12 hours. After rinsing the surface with deionized water, wastewater filter media was obtained.

[0034] During the preparation of the functional layer slurry, the solid-liquid ratio is 1:10; In the preparation of wastewater filter media, the volume ratio of sulfur autotrophic denitrifying bacteria liquid to layered substrate is 7:1. In the wastewater filter media, the thickness ratio of the lignocellulose nanofiber base layer to the functional layer slurry is 5:3. The remaining steps are the same as in Example 1.

[0035] Comparative Example 2: A wastewater treatment method based on sulfur autotrophy without added carbon source, comprising the following steps: a wastewater filter material preparation method comprising the following steps: uniformly mixing elemental sulfur and cuprous oxide / ferrous oxide heterojunction powder, adding to deionized water, adding to heat to 40℃ and stirring for 1 hour to obtain functional layer slurry; The functional layer slurry was coated onto the surface of the lignocellulose nanofiber base layer and dried at 100℃ for 2 hours to obtain a layered substrate. The layered substrate was immersed in sulfur-autotrophic denitrifying bacteria solution and anaerobically soaked at 25°C for 12 hours. After rinsing the surface with deionized water, wastewater filter media was obtained.

[0036] In the preparation of the functional layer slurry, the mass ratio of elemental sulfur to cuprous oxide / ferrous oxide heterojunction powder is 8:1, and the solid-liquid ratio is 1:10. In the preparation of wastewater filter media, the volume ratio of sulfur autotrophic denitrifying bacteria liquid to layered substrate is 7:1. In the wastewater filter media, the thickness ratio of the lignocellulose nanofiber base layer to the functional layer slurry is 5:3. The remaining steps are the same as in Example 1.

[0037] Comparative Example 3: A wastewater treatment method based on sulfur autotrophy without added carbon source, comprising the following steps: the wastewater processor body used in the wastewater treatment is an upflow processor, and the wastewater processor body consists of an inlet zone, a packing zone and an outlet zone from bottom to top. The inlet zone is connected to the inlet system, and the outlet zone is connected to the outlet system. The packing material in the packing zone is wastewater treatment filter media. The inlet COD is 180 mg / L, the pH is 6.8, the hydraulic retention time is 6 h, and the reaction temperature is 25 °C.

[0038] The preparation method of lignin cellulose nanofibers includes the following steps: placing the treated wheat straw in a 15wt% hydrogen peroxide solution, heating it to 35℃ for 3h for oxidation treatment, washing it with deionized water until the pH of the washing solution is neutral, then soaking it in a 70% ethanol solution for purification, vacuum drying at 60℃, pulverizing it to 80 mesh, and homogenizing it under high pressure at 80MPa to obtain lignin cellulose nanofibers. The preparation method of sulfur-based composite filter material includes the following steps: heating the desulfurization tailings of a paper mill to 700℃, calcining for 2.5 hours, and pulverizing to 150 mesh to obtain elemental sulfur powder; 25 mmol / L ferric nitrate nonahydrate was added to ethylene glycol to obtain a ferric nitrate nonahydrate solution. The ferric nitrate nonahydrate solution was placed in a high-pressure reactor, heated to 130°C and reacted for 3 h. After centrifugation, the precipitate was washed with deionized water and dried under vacuum at 60°C to obtain ferrous oxide powder. The above elemental sulfur powder and ferrous oxide powder were added to deionized water, heated to 60°C and stirred for 1.5 h. After centrifugation, the mixture was dried under vacuum at 60°C to obtain sulfur-based composite filter media.

[0039] The mass ratio of elemental sulfur powder to ferrous oxide powder is 4:1, and the solid-liquid ratio is 1:15.

[0040] A method for preparing cuprous oxide / ferrous oxide heterojunction powder includes the following steps: copper foam is pretreated by ultrasonically cleaning it sequentially in ethanol and 1 mol / L sulfuric acid solution for 10 minutes each, then immersed in a mixed aqueous solution of 6.9 g / L ammonium persulfate and 160 g / L sodium hydroxide, and heated to 25°C for 3 minutes to obtain copper hydroxide-loaded copper foam; the copper hydroxide-loaded copper foam is placed in a tube furnace, heated to 150°C at a rate of 5°C and held for 3 hours, then heated to 200°C and held for 3 hours, and cooled to obtain copper oxide-loaded copper foam; Copper oxide-supported copper foam was immersed in a 25 mmol / L solution of ferric nitrate nonahydrate in ethylene glycol and reacted in a high-pressure reactor at 120°C for 2 hours. After cooling, the foam was removed, washed with deionized water, and dried under vacuum at 60°C. Electrochemical activation was performed with a voltage range of +0.3V to -1.0V, a scan rate of 50mV / s, and 50 cycles to obtain cuprous oxide / ferrous oxide heterojunctions. The mixture was then exfoliated and pulverized into 200-mesh powder for later use.

[0041] A method for preparing sulfur autotrophic denitrifying bacterial solution includes the following steps: sulfur-oxidizing bacteria are inoculated into sulfur autotrophic denitrification medium and cultured anaerobicly at pH 6.8 and 25℃ for 60 hours; the components of the sulfur autotrophic denitrification medium, by mass fraction, include: 8g of elemental sulfur powder, 2g of sodium nitrate, 0.8g of potassium dihydrogen phosphate, 0.4g of magnesium sulfate, 0.2g of calcium chloride, 2mL of trace element solution, and 1000g of deionized water; the trace element solution consists of 0.01g of ferrous sulfate, 0.02g of manganese sulfate, 0.005g of copper sulfate, 0.005g of zinc sulfate, and 100mL of deionized water.

[0042] The preparation method of wastewater filter media includes the following steps: lignin cellulose nanofibers, sulfur-based composite filter media, and cuprous oxide / ferrous oxide heterojunction powder are mixed evenly, added to deionized water, heated to 40°C and stirred for 1 hour to obtain functional layer slurry; The functional layer slurry was placed in a mold and dried at 100°C for 2 hours to obtain a layered substrate. The layered substrate was immersed in sulfur-autotrophic denitrifying bacteria solution and anaerobically soaked at 25°C for 12 hours. After rinsing the surface with deionized water, wastewater filter media was obtained.

[0043] In the preparation of the functional layer slurry, the mass ratio of lignin cellulose nanofibers: sulfur-based composite filter media: cuprous oxide / ferrous oxide heterojunction powder is 10:6:1, and the solid-liquid ratio is 1:10. In the preparation of wastewater filter media, the volume ratio of sulfur autotrophic denitrifying bacteria liquid to layered substrate is 7:1. In the wastewater filter media, the thickness ratio of the lignocellulose nanofiber base layer to the functional layer slurry is 5:3.

[0044] Performance testing: After the wastewater treatment plant stabilized after 7 days of continuous operation, NO3 was measured at the inlet and outlet three times a day. - -N,PO4 3- -P, NO2 - -N, NH4 + -N concentration, calculate removal rate and accumulation; The test results are shown in Table 1 below.

[0045] Table 1 Nitrate removal rate / % Phosphate removal rate / % Nitrite accumulation / % Ammonia nitrogen production / mg / L Example 1 97.6 95.3 2.8 0.8 Example 2 98.2 95.7 2.5 0.7 Example 3 96.8 95.0 3.2 0.9 Comparative Example 1 84.7 88.2 8.5 1.5 Comparative Example 2 87.9 89.5 7.2 1.3 Comparative Example 3 90.3 91.1 5.6 1.1 Conclusion: This invention achieves efficient and simultaneous nitrogen and phosphorus removal without a carbon source through layered structure design, sulfur-based composite filter media, heterojunction catalysis, and the synergistic effect of sulfur autotrophic bacteria. It has significant technical advantages and broad application prospects.

[0046] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A wastewater treatment method based on sulfur autotrophy without added carbon source, characterized in that: The wastewater treatment method includes the following steps: the wastewater processor body used in the wastewater treatment is an upflow processor, and the wastewater processor body consists of an inlet zone, a packing zone and an outlet zone from bottom to top. The inlet zone is connected to the inlet system, the outlet zone is connected to the outlet system, and the packing material in the packing zone is wastewater treatment filter media. The wastewater filter media is prepared by coating a functional layer slurry onto the surface of a lignocellulose nanofiber base layer, drying it, and then immersing it in a sulfur-autotrophic denitrifying bacteria solution. The functional layer slurry is prepared by adding sulfur-based composite filter media and cuprous oxide / ferrous oxide heterojunction powder to deionized water.

2. The wastewater treatment method based on sulfur autotrophy without added carbon source according to claim 1, characterized in that: The preparation method of the lignocellulose nanofiber base layer includes the following steps: placing the treated agricultural waste in a 10-20wt% hydrogen peroxide solution, heating it to 30-50℃ for oxidative treatment for 2-4 hours, washing it with deionized water until the pH of the washing solution is neutral, then soaking it in a 70-75% ethanol solution for purification, vacuum drying at 60-80℃, pulverizing, and high-pressure homogenization to obtain lignocellulose nanofibers; adding the lignocellulose nanofibers to deionized water, stirring evenly, pouring it into a mold, and drying it at 80-100℃ to obtain the lignocellulose nanofiber base layer.

3. The wastewater treatment method based on sulfur autotrophy without added carbon source according to claim 2, characterized in that: In the preparation of the lignocellulose nanofiber base layer, the mass ratio of lignocellulose nanofiber to deionized water is 1:(3-5).

4. The wastewater treatment method based on sulfur autotrophy without added carbon source according to claim 1, characterized in that: The preparation method of the sulfur-based composite filter material includes the following steps: adding ferric nitrate nonahydrate to ethylene glycol to obtain ferric nitrate nonahydrate solution; placing the ferric nitrate nonahydrate solution in a high-pressure reactor, heating to 120-150℃ for 2-4 hours, centrifuging, washing the precipitate with deionized water, and vacuum drying at 60-80℃ to obtain ferrous oxide powder; adding the above elemental sulfur powder and ferrous oxide powder to deionized water, heating to 50-70℃ and stirring for 1-2 hours, centrifuging, and vacuum drying at 60-80℃ to obtain sulfur-based composite filter material.

5. The wastewater treatment method based on sulfur autotrophy without added carbon source according to claim 4, characterized in that: In the preparation of sulfur-based composite filter media, the concentration of ferric nitrate nonahydrate solution is 20-50 mmol / L; the mass ratio of elemental sulfur powder to ferrous oxide powder is (3-5):1, and the solid-liquid ratio is 1:(10-20).

6. The wastewater treatment method based on sulfur autotrophy without added carbon source according to claim 1, characterized in that: The preparation method of the cuprous oxide / ferrous oxide heterojunction powder includes the following steps: after pretreating the copper foam, it is immersed in a mixed aqueous solution of ammonium persulfate and sodium hydroxide, heated to 25-30℃ and reacted for 3-5 minutes to obtain copper hydroxide-loaded copper foam; the copper hydroxide-loaded copper foam is placed in a tube furnace, heated in stages, and cooled to obtain copper oxide-loaded copper foam. Copper oxide-loaded copper foam was immersed in ferric nitrate nonahydrate ethylene glycol solution and placed in a high-pressure reactor at 120-130℃ for 2-3 hours. After cooling, it was taken out, washed with deionized water, vacuum dried at 60-80℃, and electrochemically activated to obtain cuprous oxide / ferrous oxide heterojunctions, which were then peeled off and pulverized into powder for later use.

7. The wastewater treatment method based on sulfur autotrophy without added carbon source according to claim 6, characterized in that: In the preparation of copper oxide-supported copper foam, the concentration of ammonium persulfate aqueous solution is 6.8-7 g / L, and the concentration of sodium hydroxide aqueous solution is 150-170 g / L. The segmented heating process involves raising the temperature to 150-155℃ at a heating rate of 5-6℃ and holding for 3-4 hours, then raising it to 200-205℃ and holding for 3-4 hours. In the preparation of cuprous oxide / ferrous oxide heterojunction, the concentration of ferric nitrate nonahydrate ethylene glycol solution is 20-30 mmol / L. The voltage range for electrochemical activation is +0.3V to -1.0V, the scan rate is 45-50 mV / s, and the number of cycles is 45-50.

8. The wastewater treatment method based on sulfur autotrophy without added carbon source according to claim 1, characterized in that: The method for preparing the sulfur autotrophic denitrifying bacterial solution includes the following steps: sulfur autotrophic denitrifying functional bacteria are inoculated into a sulfur autotrophic denitrification medium and cultured anaerobicly at pH 6.5-7.0 and 25-30℃ for 48-72 hours; the sulfur autotrophic denitrifying functional bacteria include any one of sulfur-oxidizing bacteria and sulfur-driven denitrifying bacteria; the components in the sulfur autotrophic denitrification medium, by mass fraction, include: 5-10g of elemental sulfur powder, 1-3g of sodium nitrate, 0.5-1g of potassium dihydrogen phosphate, 0.2-0.5g of magnesium sulfate, 0.1-0.3g of calcium chloride, 1-3mL of trace element solution, and 1000g of deionized water; the trace element solution consists of 0.01g of ferrous sulfate, 0.02g of manganese sulfate, 0.005g of copper sulfate, 0.005g of zinc sulfate, and 100mL of deionized water.

9. The wastewater treatment method based on sulfur autotrophy without added carbon source according to claim 1, characterized in that: The preparation method of the wastewater filter material includes the following steps: mixing sulfur-based composite filter material and cuprous oxide / ferrous oxide heterojunction powder evenly, adding it to deionized water, and stirring at 40-60℃ for 1-2 hours to obtain functional layer slurry; The functional layer slurry is coated onto the surface of the lignocellulose nanofiber base layer and dried at 100-120℃ for 2-3 hours to obtain a layered substrate. The layered substrate is immersed in sulfur-autotrophic denitrifying bacteria solution and anaerobically soaked at 25-30℃ for 12-24 hours. After rinsing the surface with deionized water, wastewater filter media is obtained.

10. A wastewater treatment method based on sulfur autotrophy without added carbon source according to claim 9, characterized in that: In the preparation of the functional layer slurry, the mass ratio of sulfur-based composite filter material to cuprous oxide / ferrous oxide heterojunction powder is (5-8):1, and the solid-liquid ratio is 1:(8-12). In the preparation of wastewater filter media, the volume ratio of sulfur autotrophic denitrifying bacteria liquid to layered substrate is (5-10):

1. In the wastewater filter media, the thickness ratio of the lignocellulose nanofiber base layer to the functional layer slurry is (2-5):(1-3).