Artificial wetland system for synchronously removing nitrogen and antimony through enrichment and denitrification of anaerobic ammonium oxidation bacteria induced by iron-carbon micro-electrolysis and operation method of artificial wetland system

Abstract

The invention belongs to the technical field of treatment of a mixture of antimony-containing mine well water and domestic sewage, and particularly discloses an artificial wetland system for nitrogen removal and antimony removal synchronously through iron-carbon micro-electrolysis induced anaerobic ammonium oxidation bacteria enrichment and an operation method of the artificial wetland system. The method is used for solving the problems that the current iron-carbon micro-electrolysis technology is lack of deep fusion with an artificial wetland system, and synchronous nitrogen and antimony removal and functional bacteria coordinated regulation and control are not realized. The constructed wetland system comprises a water inlet unit, a reaction unit, a circulating reflux unit, a dosing unit, an intelligent control unit and a water outlet unit; wherein the reaction unit comprises an iron-carbon micro-electrolysis module embedded in the reaction unit and acorus calamus planted on the upper surface layer of the reaction unit, the iron-carbon micro-electrolysis module comprises an outer ring area, a central area and a conductive carbon fiber net, the outer ring area is filled with iron-based filler, the central area is filled with activated carbon, and the space between the outer ring area and the central area is filled with zeolite filler and limestone. According to the invention, efficient synergistic removal of pollutants and rapid enrichment of functional bacteria can be realized, and the system operation stability is high.

Description

Technical Field

[0001] This invention belongs to the field of treatment technology for mixtures of antimony-containing mine water and domestic sewage, and particularly relates to an artificial wetland system and its operation method for the simultaneous enrichment, denitrification, and antimony removal of anaerobic ammonia-oxidizing bacteria induced by iron-carbon micro-electrolysis. Background Technology

[0002] With the acceleration of industrialization and urbanization, the pollution problem of antimony-containing wastewater discharged from mining activities has become increasingly serious. Antimony mines and non-ferrous metal mines often generate high-concentration antimony-containing mine water during mining, beneficiation, and smelting processes. The antimony concentration in this water is generally 0.1–10 mg / L, and in some cases even exceeds 50 mg / L, far exceeding the limit for antimony (0.01 mg / L) in the "Groundwater Environmental Quality Standard" (GB / T 14848-2017), posing a significant threat to the safety of surrounding groundwater. It is worth noting that the daily lives of mine workers also generate a large amount of domestic sewage, which generally suffers from insufficient carbon sources and significant nitrogen pollution, requiring efficient denitrification as well. Traditionally, domestic sewage and mine water are often treated separately, increasing operating costs and spatial constraints. If the two types of water sources can be treated collaboratively, it can not only simplify the treatment process and save investment costs, but also avoid the impact of fluctuations in a single water source on system stability. However, the common challenge of this type of complex wastewater lies in the need for efficient removal of heavy metals such as antimony, while simultaneously achieving denitrification under low-carbon conditions and minimizing disturbance to the ecosystems of sensitive mining areas and the risk of secondary pollution. This places higher demands on the compatibility and eco-friendliness of water treatment systems. In particular, trivalent antimony, with its strong toxicity and bioaccumulation, inhibits the functional community of microorganisms, severely interfering with the denitrification efficiency and stability of wastewater treatment systems.

[0003] Constructed wetlands, as a green and low-consumption ecological treatment technology, have been widely used in nitrogen removal, especially when coupled with functions such as anaerobic ammonia oxidation, demonstrating excellent denitrification capabilities. However, when treating mixtures of antimony-containing mine water and domestic sewage, several challenges remain: existing systems primarily rely on matrix adsorption for antimony removal, which is prone to adsorption saturation and antimony re-release during long-term operation; antimony has an inhibitory effect on core microbial communities, particularly hindering the growth of anaerobic ammonia oxidizing bacteria; and the poor conductivity and insufficient electron donors in wetland systems also limit the denitrification reaction rate, making it difficult to achieve the engineering goal of simultaneous and efficient denitrification and heavy metal treatment.

[0004] Iron-carbon micro-electrolysis technology generates Fe due to its internal galvanic cell reaction. 2+ OH - In a micro-electric field environment, redox reactions can be induced in situ, which has become a research hotspot in recent years for improving the electron supply and heavy metal removal efficiency of wastewater systems. Among them, Fe 2+It can form stable, insoluble iron-antimony ore precipitates (such as FeSbO4) with antimony, significantly reducing its biotoxicity; at the same time, OH - It can adjust pH to buffer acidity and improve system stability; the electrons released by micro-electrolysis can also serve as direct electron donors for denitrifying microorganisms, significantly enhancing the metabolic capacity of anaerobic ammonia-oxidizing bacteria. Recent research indicates that Fe... 2+ It promotes cell membrane permeability and adhesion growth of anaerobic ammonia-oxidizing bacteria, facilitating their rapid accumulation and biofilm formation. However, current iron-carbon microelectrolysis technology is mostly applied as an independent unit for the treatment of heavy metal or organic pollution, lacking deep integration with constructed wetland systems, and has not yet achieved the goal of simultaneous nitrogen and antimony removal and synergistic regulation of functional bacteria. Summary of the Invention

[0005] One objective of this invention is to provide an artificial wetland system that induces anaerobic ammonia-oxidizing bacteria to enrich, denitrify, and simultaneously remove antimony via iron-carbon microelectrolysis. This effectively addresses the current problem that iron-carbon microelectrolysis technology lacks deep integration with artificial wetland systems and has not yet achieved simultaneous denitrification, antimony removal, and synergistic regulation of functional bacteria.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: an artificial wetland system for simultaneous antimony removal and anaerobic ammonia oxidizing bacteria enrichment through iron-carbon micro-electrolysis, comprising an inlet unit, a reaction unit, a circulation and reflux unit, a dosing unit, an intelligent control unit, and an outlet unit; the inlet unit is used to receive and transport mixed wastewater containing antimony mine water and domestic sewage, and the outlet unit is used for the storage and transportation of purified water; the reaction unit includes an inlet, an iron-carbon micro-electrolysis module, yellow iris, and an outlet, the inlet being located at the bottom of the reaction unit, the outlet at the top of the reaction unit, the yellow iris being planted on the upper surface of the reaction unit, and an iron-carbon micro-electrolysis module embedded inside the reaction unit, the iron-carbon micro-electrolysis module comprising an outer ring region, a central region, and conductive carbon fibers. The reactor consists of a mesh, with the outer ring area filled with iron-based filler and the central area filled with activated carbon. The outer ring area and the central area are connected by a conductive carbon fiber mesh to form a continuous electron transfer channel. Zeolite filler and limestone are filled between the outer ring area and the central area. The circulation reflux unit is used to transport part of the effluent from the reactor to the bottom of the reactor at a reflux ratio of 0-60%. The dosing unit is used to adjust the pH of the wastewater in the reactor. The intelligent control unit includes a monitoring probe and a central control system. The monitoring probe is used to monitor the pH and the concentrations of antimony, ammonia nitrogen, and nitrate at the outlet of the reactor. The central control system is used to receive monitoring data from the monitoring probe and dynamically adjust the operation of relevant equipment according to preset control logic and real-time feedback.

[0007] Furthermore, the iron-based filler has a particle size of 4-5 mm, the activated carbon has a particle size of 4-5 mm, and the conductive carbon fiber mesh has a pore size of 1-2 mm.

[0008] Furthermore, the zeolite filler has a particle size of 2-4 mm, the limestone has a particle size of 3-5 mm, and the zeolite filler and limestone are filled between the outer ring region and the central region in a volume ratio of 1:1.

[0009] Furthermore, the water inlet unit includes an inlet tank for receiving mixed wastewater containing antimony mine water and domestic sewage, an inlet pump for dynamically adjusting the inlet rate according to flow fluctuations, and an inlet pipe for connecting the inlet tank and the inlet of the reaction unit; the water outlet unit includes an outlet tank for temporarily storing purified water, an outlet pump, and an outlet pipe for connecting the outlet tank and the outlet of the reaction unit.

[0010] Furthermore, the dosing unit includes an acidic dosing tank, an acidic dosing pump, an alkaline dosing tank, an alkaline dosing pump, and a dosing pipe. The acidic dosing tank contains hydrochloric acid solution, and the alkaline dosing tank contains sodium hydroxide solution. The circulation reflux unit includes a reflux pipe and a reflux pump.

[0011] Furthermore, the reaction unit is cylindrical, and the outer ring region of the iron-carbon micro-electrolysis module is closely attached to the inner wall of the reaction unit. The height of the iron-carbon micro-electrolysis module is equal to the height of the reaction unit.

[0012] Another objective of this invention is to provide an operation method for the constructed wetland system described in the above embodiments, which uses iron-carbon micro-electrolysis to induce anaerobic ammonia oxidizing bacteria for enrichment, denitrification, and simultaneous antimony removal. The method includes the following steps: S1, screening short-range nitrifying bacteria and anaerobic ammonia oxidizing bacteria from acclimated activated sludge, with an initial MLSS of 5000 mg / L, inoculating them into the reaction unit, and using high-ammonia nitrogen antimony-containing wastewater as influent, which is then transported to the inlet of the reaction unit through the influent unit.

[0013] S2. Wastewater flows into the reaction unit, and the circulation reflux unit injects part of the effluent from the reaction unit into the bottom of the reaction unit at a reflux ratio of 45%.

[0014] S3, the iron-based filler in the iron-carbon micro-electrolysis module acts as the anode, undergoing an oxidation reaction to continuously release Fe. 2+ Activated carbon, acting as the cathode, receives electrons through a conductive carbon fiber mesh to generate active hydrogen in an acidic microenvironment. Fe 2+ It combines with pentavalent antimony in wastewater to form FeSbO4 precipitate, with OH as a byproduct. - In synergy with the dosing unit, the pH value of the water environment within the reaction unit is 6.5–7.5.

[0015] Simultaneously, the wastewater comes into contact with the zeolite packing material, which adsorbs the oxygen-containing anions of antimony onto its surface and into its pores through electrostatic attraction, thus achieving dual-pathway immobilization of antimony.

[0016] S4. A micro-oxygen zone is formed at the contact point between the yellow iris and the zeolite packing, where some Fe... 2+ Oxidized to Fe 3+ It generates FeOOH colloids that can adsorb free antimony ions. Iris tectorum converts trivalent antimony into an antimony-glutathione complex through its xylem chelating protein, reducing the risk of secondary release.

[0017] S5. Yellow iris attaches short-range nitrifying bacteria in the microaerobic zone, oxidizing residual ammonia nitrogen into nitrite nitrogen, thus realizing the short-range nitrification process and replenishing the substrate for anaerobic ammonia oxidation.

[0018] In Fe 2+ Under stimulation, anaerobic ammonia oxidizing bacteria secrete extracellular polysaccharide-protein polymers to form biofilms, enriching the anaerobic ammonia oxidizing bacteria. At the same time, the generated nitrite nitrogen and influent ammonia nitrogen are utilized by the anaerobic ammonia oxidizing bacteria, promoting the denitrification reaction.

[0019] The conductive carbon fiber mesh transports micro-electrolysis electrons to the cell membrane of anaerobic ammonia oxidizing bacteria, increasing the electron transfer efficiency of anaerobic ammonia oxidation by 40%. At the same time, the increased electron flux stabilizes the denitrification rate of anaerobic ammonia oxidizing bacteria at 0.8–1.2 mg N / (gVSS·h).

[0020] S6. The monitoring probe collects the pH value, ammonia nitrogen concentration, and antimony concentration at the outlet of the reaction unit in real time, and transmits the collected data to the central control system. The central control system dynamically adjusts the operation of relevant equipment to ensure that the ammonia nitrogen concentration of the treated wastewater is not greater than 1.5 mg / L and the antimony concentration is not greater than 0.01 mg / L. Finally, the treated wastewater is discharged through the effluent unit.

[0021] Furthermore, in step S6, when the ammonia nitrogen concentration is greater than 1.5 mg / L, the central control system controls the inlet water unit to reduce the inlet water flow rate, extends the hydraulic retention time from the baseline 8 hours to 12 hours, and increases the reflux ratio, injecting part of the effluent from the reaction unit into the bottom of the reaction unit through the circulation reflux unit to ensure that the conversion rate of ammonia nitrogen and nitrite nitrogen is greater than 99%.

[0022] When the ammonia nitrogen concentration is less than 1.5 mg / L, the central control system controls the water inlet unit to increase the water flow rate, shorten the hydraulic residence time to 6 hours, and at the same time reduce the reflux ratio, so that part of the effluent from the reaction unit is injected into the bottom of the reaction unit through the circulation reflux unit.

[0023] When the antimony concentration is greater than 0.01 mg / L, the central control system controls the circulation reflux unit to increase the reflux ratio, injecting part of the effluent from the reaction unit into the bottom of the reaction unit through the circulation reflux unit, so that the antimony concentration in the influent is diluted to less than 2 mg / L, and at the same time the system reduction potential is increased to below -150 mV.

[0024] Furthermore, in step S1, the concentration of antimony in the high ammonia nitrogen-containing antimony wastewater is 0.5–2.0 mg / L, and the concentration of ammonia nitrogen is 5.0–20.0 mg / L.

[0025] Furthermore, to maintain the long-term operation of the system, 10% of the iron-based packing is replenished every quarter, activated carbon is regenerated by sun exposure every year, and the zeolite packing is replaced when the antimony adsorption capacity in the zeolite packing reaches 10-12 mg / g.

[0026] Compared with the prior art, the beneficial technical effects of the present invention are:

[0027] (1) This invention deeply couples the iron-carbon micro-electrolysis module with the constructed wetland system, Fe 2+ During the in-situ generation of active hydrogen, it promotes antimony reduction and precipitation fixation on the one hand, and acts as an electron donor to drive anaerobic ammonium oxidation on the other, achieving simultaneous and efficient removal of nitrogen and antimony, with a total removal rate of over 95% (effluent total nitrogen less than 1.5 mg / L, effluent antimony less than 0.01 mg / L); simultaneously, Fe 2+ It promotes the formation of anaerobic ammonia-oxidizing bacteria biofilm, shortening its enrichment cycle to less than 20 days and significantly improving the system start-up efficiency.

[0028] (2) The present invention releases OH through micro-electrolysis - Neutralizing acidic environments, Fe 2+ The combined effect of chelation precipitation of free antimony and a partial high-concentration reflux dilution strategy effectively reduces the toxic inhibition of heavy metals on anaerobic ammonia-oxidizing bacteria, maintaining the stability of the microbial community structure and functional activity.

[0029] (3) This invention combines online monitoring methods to dynamically regulate the hydraulic residence time and pH value, thereby achieving precise regulation of the wetland reaction environment. Even under complex water quality conditions where the antimony concentration fluctuates within the range of 2 to 5 mg / L, the effluent water quality can still be kept stable, improving the system's shock resistance and operational robustness.

[0030] (4) The operation of this invention does not require additional organic carbon source, which reduces the cost of carbon source replenishment; various fillers have good reactivity and renewability, and can maintain the function of iron-carbon micro-electrolysis module through intermittent feeding. The overall energy consumption and chemical consumption of the system are low, and the comprehensive operating cost is reduced by about 30% to 40% compared with the traditional denitrification and antimony removal process, which has good prospects for promotion and application. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the connection structure of the artificial wetland system of the present invention.

[0032] Figure 2 yes Figure 1 A cross-sectional view of the reaction unit in the middle.

[0033] Figure 3 This is a flowchart of the operation of the artificial wetland system of the present invention, wherein solid lines represent the operation process and dashed lines represent the control process.

[0034] Explanation of reference numerals in the attached diagram: Inlet tank - 1; Inlet pipe - 2; Inlet pump - 3; Inlet - 4; Reaction unit - 5; Iron-carbon micro-electrolysis module - 6; Conductive carbon fiber mesh - 7; Iron-based filler - 8; Activated carbon - 9; Zeolite filler - 10; Limestone - 11; Monitoring probe - 12; Central control system - 13; Yellow iris - 14; Outlet - 15; Return pump - 16; Return pipe - 17; Acidic dosing tank - 18; Acidic dosing pump - 19; Alkaline dosing tank - 20; Alkaline dosing pump - 21; Dosing pipe - 22; Outlet pipe - 23; Outlet pump - 24; Outlet tank - 25. Detailed Implementation

[0035] Example 1: An artificial wetland system for simultaneous antimony removal and anaerobic ammonia-oxidizing bacteria enrichment and denitrification induced by iron-carbon micro-electrolysis, such as... Figure 1 As shown, it includes an inlet unit, a reaction unit 5, a circulation and recirculation unit, a dosing unit, an intelligent control unit, and an outlet unit.

[0036] The inlet unit is used to receive and transport mixed wastewater containing antimony mine water and domestic sewage. The inlet unit includes an inlet tank 1 for receiving the mixed wastewater and a system for dynamically adjusting the inlet rate (0.5–2 m / s) based on flow fluctuations. 3 The system includes a water inlet pump 3 ( / h) and an inlet pipe 2 for connecting the water inlet tank 1 and the reaction unit 5 via an inlet 4.

[0037] like Figure 1 and Figure 2 As shown, the reaction unit 5 adopts a cylindrical structure, including an inlet 4, an iron-carbon micro-electrolysis module 6, yellow iris 14, and an outlet 15. The inlet 4 is located at the bottom of the reaction unit 5, allowing wastewater to enter the unit and rise evenly. The outlet 15 is located at the top of the reaction unit 5 and connects to the outlet unit. The outlet unit is used for the storage and transportation of purified water, and includes an outlet tank 25 for temporary storage of purified water, an outlet pump 24, and an outlet pipe 23 connecting the outlet tank 25 to the outlet 15 of the reaction unit 5. Yellow iris 14 is planted as a wetland plant on the upper surface of the reaction unit 5 to enhance the root micro-aerobic environment and absorb residual nitrogen.

[0038] like Figure 2As shown, an iron-carbon micro-electrolysis module 6 is embedded inside the reaction unit 5. The iron-carbon micro-electrolysis module 6 includes an outer ring region, a central region, and a conductive carbon fiber mesh 7. The outer ring region of the iron-carbon micro-electrolysis module 6 is set close to the inner sidewall of the reaction unit 5, and the height of the iron-carbon micro-electrolysis module 6 is equal to the height of the reaction unit 5. The outer ring region is filled with iron-based filler 8 with a particle size of 4-5 mm, and the central region is filled with activated carbon 9 with a particle size of 4-5 mm. The outer ring region and the central region are connected by a conductive carbon fiber mesh 7 with a pore size of 1-2 mm to form a continuous electron transfer channel. The interior of the reaction unit 5 is filled with zeolite filler 10 and limestone 11 between the outer ring region and the central region for anaerobic ammonia oxidizing bacteria attachment and denitrification reaction. In this embodiment, the particle size of the zeolite filler 10 is 2-4 mm, and the particle size of the limestone 11 is 3-5 mm. The zeolite filler 10 and limestone 11 are filled between the outer ring region and the central region of the iron-carbon micro-electrolysis module 6 in a volume ratio of 1:1.

[0039] The circulation reflux unit includes a reflux pipe 17 and a reflux pump 16, which can transport part of the effluent from the reaction unit 5 to the bottom of the reaction unit 5 at a reflux ratio of 0 to 60% to dilute the high concentration of antimony shock and adjust the reduction potential in the reaction unit 5.

[0040] The intelligent control unit includes a monitoring probe 12 and a central control system 13. The monitoring probe 12 integrates online detection modules for antimony, ammonia nitrogen, nitrate, and pH, used to monitor the pH and the concentrations of antimony, ammonia nitrogen, and nitrate at the outlet 15 of reaction unit 5. The monitoring data is synchronously transmitted to the central control system 13. The central control system 13 receives the monitoring data from the monitoring probe 12 and dynamically adjusts the operation of relevant equipment according to preset control logic and real-time feedback.

[0041] The dosing unit is used to adjust the pH of the wastewater in reaction unit 5. The dosing unit includes an acid dosing tank 18, an acid dosing pump 19, an alkaline dosing tank 20, an alkaline dosing pump 21, and a dosing pipe 22. The acid dosing tank 18 contains a 1 mol / L hydrochloric acid solution, and the alkaline dosing tank 20 contains a 1 mol / L sodium hydroxide solution.

[0042] This embodiment enhances the system's reduction environment and electron supply by incorporating an iron-carbon micro-electrolysis module 6 into the constructed wetland system. 2+ In-situ release can efficiently precipitate antimony ions in water, alleviating their biotoxicity, while simultaneously promoting the accumulation of anaerobic ammonia-oxidizing bacteria and shortening the start-up period; the micro-electric field enhances microbial activity, OH... - This embodiment buffers the acidic environment of mine water and enhances the system's resistance to load shocks. It provides an operational method for an constructed wetland system, overcoming the bottlenecks of low heavy metal treatment efficiency and difficulty in starting anaerobic ammonia oxidation in traditional wetlands. It offers a green and sustainable technological path for the co-treatment of high-antimony mine water and domestic sewage.

[0043] Example 2: An artificial wetland system based on Example 1, which uses iron-carbon micro-electrolysis to induce anaerobic ammonia-oxidizing bacteria for enrichment, denitrification, and simultaneous antimony removal, has the following specific steps.

[0044] S1. Short-range nitrifying bacteria and anaerobic ammonia-oxidizing bacteria were screened from the acclimated activated sludge. The initial MLSS was 5000 mg / L. The bacteria were inoculated into reaction unit 5, using high-ammonia nitrogen antimony-containing wastewater as the influent, which was transported to inlet 4 of reaction unit 5 through the influent unit. The concentration of antimony in the high-ammonia nitrogen antimony-containing wastewater was 0.5–2.0 mg / L, and the concentration of ammonia nitrogen was 5.0–20.0 mg / L.

[0045] S2. Wastewater flows into reaction unit 5 and continues to flow upward. The reflux pump 16 of the circulation reflux unit injects part of the effluent from reaction unit 5 into the bottom of reaction unit 5 through reflux pipe 17 at a reflux ratio of 45%.

[0046] S3, the iron-based filler 8 in the iron-carbon micro-electrolysis module 6 acts as the anode, undergoing an oxidation reaction to continuously release Fe. 2+ Activated carbon 9, acting as the cathode, receives electrons through conductive carbon fiber mesh 7 to generate active hydrogen in an acidic microenvironment. Fe 2+ It combines with pentavalent antimony in wastewater to form insoluble FeSbO4 precipitate. OH is a byproduct of iron-carbon microelectrolysis technology. - In synergy with the dosing unit, the pH value of the water environment in reaction unit 5 is regulated to 6.5–7.5, which reduces the solubility of trivalent antimony by more than 60% and significantly reduces the toxicity of heavy metals.

[0047] Simultaneously, the wastewater comes into contact with the zeolite packing 10. Based on its unique porous structure and surface charge characteristics, the zeolite packing 10 adsorbs the oxygen-containing anions of antimony onto its surface and into its pores through electrostatic attraction, thereby achieving dual-path immobilization of antimony.

[0048] S4. The root system of *Iris tectorum* 14, planted on the upper surface of reaction unit 5, reaches a depth of 40–60 cm, with an average daily oxygen secretion of 0.8–1.2 mg / L. A micro-oxygen zone is formed at the contact point between *Iris tectorum* 14 and zeolite filler 10, where some Fe... 2+ Oxidized to Fe 3+ It generates FeOOH colloids that can adsorb free antimony ions. Iris tectorum 14 can also convert trivalent antimony into antimony-glutathione complex through its xylem chelating protein, reducing the risk of secondary release.

[0049] S5 and Iris tectorum 14 have short-range nitrifying bacteria attached to the microaerobic zone, which can oxidize residual ammonia nitrogen into nitrite nitrogen, realize the short-range nitrification process, and supplement the substrate for anaerobic ammonia oxidation.

[0050] In Fe 2+Under stimulation, anaerobic ammonia oxidizing bacteria secrete extracellular polysaccharide-protein polymers, forming a biofilm with a thickness of 200-300 μm within 20 days, successfully enriching the anaerobic ammonia oxidizing bacteria. At the same time, the generated nitrite nitrogen and influent ammonia nitrogen are used by the anaerobic ammonia oxidizing bacteria together, promoting the denitrification reaction.

[0051] The high-speed electron channel constructed by the conductive carbon fiber mesh 7 delivers micro-electrolysis electrons to the cell membrane of anaerobic ammonia oxidizing bacteria, promoting an increase of 40% in the electron transfer efficiency of anaerobic ammonia oxidation. At the same time, the enhanced electron flux stabilizes the denitrification rate of anaerobic ammonia oxidizing bacteria at 0.8–1.2 mg N / (g VSS·h).

[0052] S6. The monitoring probe 12 collects the pH value, ammonia nitrogen concentration and antimony concentration at the outlet 15 of the reaction unit 5 in real time, and transmits the collected data to the central control system 13 for dynamic optimization.

[0053] (1) When the pH value is greater than 7.5, the central control system 13 controls the acid dosing pump 19 to start and add 1 mol / L hydrochloric acid solution to the reaction unit 5 to lower the pH value; when the pH value is less than 6.5, the central control system 13 controls the alkaline dosing pump 21 to start and add 1 mol / L sodium hydroxide solution to raise the pH value, so that the pH value of the water environment in the reaction unit 5 is stabilized at 6.5 to 7.5.

[0054] (2) When the ammonia nitrogen concentration is greater than 1.5 mg / L, the central control system 13 controls the inlet pump 3 to reduce the inlet flow rate and automatically extends the hydraulic residence time from the baseline 8h to 12h. At the same time, the reflux ratio is increased, and part of the effluent from the reaction unit 5 is injected into the bottom of the reaction unit 5 through the reflux pipe 17 to ensure that the conversion rate of ammonia nitrogen and nitrite nitrogen is greater than 99% to ensure the complete anaerobic ammonia oxidation reaction. When the ammonia nitrogen concentration is less than 1.5 mg / L, the central control system 13 controls the inlet pump 3 to increase the inlet flow rate and shorten the hydraulic residence time to 6h. At the same time, the reflux ratio is reduced, and part of the effluent from the reaction unit 5 is injected into the bottom of the reaction unit 5 through the reflux pipe 17, and the system processing throughput is increased by 25%.

[0055] (3) In the case of antimony concentration exceeding the standard, when the antimony concentration is greater than 0.01 mg / L, the central control system 13 controls the return pump 16 to increase the return ratio, and injects part of the effluent from the reaction unit 5 into the bottom of the reaction unit 5 through the return pipe 17, so that the antimony concentration in the influent is diluted to less than 2 mg / L (safe threshold), and at the same time the system reduction potential is increased to below -150 mV, so as to ensure that the antimony concentration in the wastewater is less than 0.01 mg / L.

[0056] S7. The treated wastewater enters the effluent pipe 23 through the effluent outlet 15 and is then pumped to the effluent tank 25 by the effluent pump 24. To maintain the long-term operation of the system, 10% of the iron-based packing 8 is added quarterly to regenerate the micro-electrolysis activity and remove the surface oxide layer; the activated carbon 9 is regenerated by sun exposure every year to restore its adsorption capacity; the antimony concentration adsorbed in the zeolite packing 10 is monitored, and the zeolite packing 10 is replaced when the amount of antimony adsorbed in the zeolite packing 10 reaches 10-12 mg / g.

[0057] The operation of this invention does not require an additional external organic carbon source, thus reducing the cost of carbon source replenishment. Various fillers have good reactivity and renewability, and the function of the iron-carbon micro-electrolysis module 6 can be maintained by intermittent feeding. The overall energy consumption and chemical consumption of the system are low, and the comprehensive operating cost is reduced by about 30% to 40% compared with the traditional denitrification and antimony removal process, which has good prospects for promotion and application.

[0058] This invention achieves deep coupling of the iron-carbon micro-electrolysis module 6 with the constructed wetland system, Fe 2+ During the in-situ generation of active hydrogen, it promotes antimony reduction and precipitation fixation on the one hand, and acts as an electron donor to drive anaerobic ammonium oxidation on the other, achieving simultaneous and efficient removal of nitrogen and antimony, with a total removal rate of over 95% (effluent total nitrogen less than 1.5 mg / L, effluent antimony less than 0.01 mg / L); simultaneously, Fe 2+ It promotes the formation of anaerobic ammonia-oxidizing bacteria biofilm, shortening its enrichment cycle to less than 20 days and significantly improving the system start-up efficiency.

[0059] This invention combines online monitoring to dynamically regulate hydraulic retention time and pH value, achieving precise control of the wetland reaction environment. Even under complex water quality conditions with antimony concentration fluctuations ranging from 2 to 5 mg / L, it can maintain stable effluent quality, improving the system's shock resistance and operational robustness. This invention utilizes micro-electrolysis to release OH... - Neutralizing acidic environments, Fe 2+ The combined effect of chelation precipitation of free antimony and a partial high-concentration reflux dilution strategy effectively reduces the toxic inhibition of heavy metals on anaerobic ammonia-oxidizing bacteria, maintaining the stability of the microbial community structure and functional activity.

[0060] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. An artificial wetland system for simultaneous antimony removal and anaerobic ammonia-oxidizing bacteria enrichment and denitrification induced by iron-carbon micro-electrolysis, characterized in that, It includes an inlet unit, a reaction unit, a circulation and recirculation unit, a dosing unit, an intelligent control unit, and an outlet unit; The water inlet unit is used to receive and transport mixed wastewater containing antimony mine water and domestic sewage, and the water outlet unit is used for the storage and transportation of purified water. The reaction unit includes an inlet, an iron-carbon micro-electrolysis module, iris, and an outlet. The inlet is located at the bottom of the reaction unit, and the outlet is located at the top. The iris is planted on the upper surface of the reaction unit. An iron-carbon micro-electrolysis module is embedded inside the reaction unit. The iron-carbon micro-electrolysis module includes an outer ring region, a central region, and a conductive carbon fiber mesh. The outer ring region is filled with iron-based filler, and the central region is filled with activated carbon. The outer ring region and the central region are connected by the conductive carbon fiber mesh to form a continuous electron transfer channel. Zeolite filler and limestone are filled between the outer ring region and the central region. The circulating reflux unit is used to transport a portion of the effluent from the reaction unit to the bottom of the reaction unit at a reflux ratio of 0-60%; the dosing unit is used to adjust the pH of the wastewater in the reaction unit; the intelligent control unit includes a monitoring probe and a central control system. The monitoring probe is used to monitor the pH and the concentrations of antimony, ammonia nitrogen, and nitrate at the outlet of the reaction unit. The central control system is used to receive monitoring data from the monitoring probe and dynamically adjust the operation of relevant equipment according to preset control logic and real-time feedback.

2. The constructed wetland system for simultaneous antimony removal and anaerobic ammonia-oxidizing bacteria enrichment, denitrification, and antimony removal induced by iron-carbon micro-electrolysis according to claim 1, characterized in that, The iron-based filler has a particle size of 4-5 mm, the activated carbon has a particle size of 4-5 mm, and the conductive carbon fiber mesh has a pore size of 1-2 mm.

3. The constructed wetland system for simultaneous antimony removal and anaerobic ammonia-oxidizing bacteria enrichment, denitrification, and antimony removal induced by iron-carbon micro-electrolysis according to claim 2, characterized in that, The zeolite filler has a particle size of 2-4 mm, and the limestone has a particle size of 3-5 mm. The zeolite filler and limestone are filled between the outer ring region and the central region in a volume ratio of 1:

1.

4. The constructed wetland system for simultaneous antimony removal and anaerobic ammonia-oxidizing bacteria enrichment, denitrification, and antimony removal induced by iron-carbon micro-electrolysis according to claim 3, characterized in that, The water inlet unit includes an inlet tank for receiving mixed wastewater of antimony mine water and domestic sewage, an inlet pump for dynamically adjusting the inlet rate according to flow fluctuations, and an inlet pipe for connecting the inlet tank and the inlet of the reaction unit. The water outlet unit includes a water outlet tank for temporarily storing purified water, a water outlet pump, and a water outlet pipe for connecting the water outlet tank and the water outlet of the reaction unit.

5. The constructed wetland system for simultaneous antimony removal and anaerobic ammonia-oxidizing bacteria enrichment, denitrification, and antimony removal induced by iron-carbon micro-electrolysis according to claim 4, characterized in that, The dosing unit includes an acid dosing tank, an acid dosing pump, an alkaline dosing tank, an alkaline dosing pump, and a dosing pipe. The acid dosing tank contains hydrochloric acid solution, and the alkaline dosing tank contains sodium hydroxide solution. The recirculation unit includes a recirculation pipe and a recirculation pump.

6. The constructed wetland system for simultaneous antimony removal and anaerobic ammonia-oxidizing bacteria enrichment, denitrification, and antimony removal induced by iron-carbon micro-electrolysis according to claim 5, characterized in that, The reaction unit is cylindrical, and the outer ring region of the iron-carbon micro-electrolysis module is closely attached to the inner wall of the reaction unit. The height of the iron-carbon micro-electrolysis module is equal to the height of the reaction unit.

7. The operation method of the constructed wetland system for simultaneous antimony removal and enrichment of anaerobic ammonia-oxidizing bacteria induced by iron-carbon micro-electrolysis according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Short-range nitrifying bacteria and anaerobic ammonia-oxidizing bacteria were screened from the acclimated activated sludge. The initial MLSS was 5000 mg / L. The bacteria were inoculated into the reaction unit and high ammonia nitrogen antimony-containing wastewater was used as the influent. The wastewater was transported to the inlet of the reaction unit through the influent unit. S2. Wastewater flows into the reaction unit, and the circulation and recirculation unit injects part of the effluent from the reaction unit into the bottom of the reaction unit at a recirculation ratio of 45%. S3. In the iron-carbon micro-electrolysis module, the iron-based filler acts as the anode, undergoing an oxidation reaction to continuously release Fe. 2+ Activated carbon serves as the cathode, receiving electrons through a conductive carbon fiber mesh to generate active hydrogen in an acidic microenvironment; Fe 2+ It combines with pentavalent antimony in wastewater to form FeSbO4 precipitate, with OH as a byproduct. - In synergy with the dosing unit, the pH value of the water environment within the reaction unit is regulated to be 6.5–7.5; Simultaneously, the wastewater comes into contact with the zeolite packing, and the zeolite packing adsorbs the oxygen-containing anions of antimony onto its surface and into its pores through electrostatic attraction, thus achieving dual-pathway immobilization of antimony. S4. A micro-oxygen zone is formed at the contact point between the yellow iris and the zeolite packing, where some Fe... 2+ Oxidized to Fe 3+ It generates FeOOH colloids that can adsorb free antimony ions. Iris tectorum converts trivalent antimony into an antimony-glutathione complex through its xylem chelating protein, reducing the risk of secondary release. S5. Yellow iris attaches short-range nitrifying bacteria in the microaerobic zone, oxidizing residual ammonia nitrogen into nitrite nitrogen, realizing the short-range nitrification process and replenishing the substrate for anaerobic ammonia oxidation; In Fe 2+ Under stimulation, anaerobic ammonia oxidizing bacteria secrete extracellular polysaccharide-protein polymers to form biofilms, enriching the anaerobic ammonia oxidizing bacteria. At the same time, the generated nitrite nitrogen and influent ammonia nitrogen are used by the anaerobic ammonia oxidizing bacteria, promoting the denitrification reaction. Conductive carbon fiber mesh delivers micro-electrolysis electrons to the cell membrane of anaerobic ammonia oxidizing bacteria, increasing the electron transfer efficiency of anaerobic ammonia oxidation by 40%. At the same time, the increased electron flux stabilizes the denitrification rate of anaerobic ammonia oxidizing bacteria at 0.8–1.2 mg N / (gVSS·h). S6. The monitoring probe collects the pH value, ammonia nitrogen concentration, and antimony concentration at the outlet of the reaction unit in real time, and transmits the collected data to the central control system. The central control system dynamically adjusts the operation of relevant equipment to ensure that the ammonia nitrogen concentration of the treated wastewater is not greater than 1.5 mg / L and the antimony concentration is not greater than 0.01 mg / L. Finally, the treated wastewater is discharged through the effluent unit.

8. The operation method of the constructed wetland system for simultaneous antimony removal and enrichment of anaerobic ammonia-oxidizing bacteria induced by iron-carbon micro-electrolysis according to claim 7, characterized in that, In step S6, when the ammonia nitrogen concentration is greater than 1.5 mg / L, the central control system controls the water inlet unit to reduce the water inflow, extends the hydraulic retention time from the baseline 8 hours to 12 hours, and increases the reflux ratio, injecting part of the effluent from the reaction unit into the bottom of the reaction unit through the circulation reflux unit to ensure that the conversion rate of ammonia nitrogen and nitrite nitrogen is greater than 99%. When the ammonia nitrogen concentration is less than 1.5 mg / L, the central control system controls the water inlet unit to increase the water flow rate, shorten the hydraulic retention time to 6 hours, and at the same time reduce the reflux ratio, so that part of the effluent from the reaction unit is injected into the bottom of the reaction unit through the circulation reflux unit. When the antimony concentration is greater than 0.01 mg / L, the central control system controls the circulation reflux unit to increase the reflux ratio, injecting part of the effluent from the reaction unit into the bottom of the reaction unit through the circulation reflux unit, so that the antimony concentration in the influent is diluted to less than 2 mg / L, and at the same time the system reduction potential is increased to below -150 mV.

9. The operation method of the constructed wetland system for simultaneous antimony removal and enrichment of anaerobic ammonia-oxidizing bacteria induced by iron-carbon micro-electrolysis according to claim 7, characterized in that, In step S1, the concentration of antimony in the high ammonia nitrogen antimony wastewater is 0.5–2.0 mg / L and the concentration of ammonia nitrogen is 5.0–20.0 mg / L.

10. The operation method of the constructed wetland system for simultaneous antimony removal and enrichment of anaerobic ammonia-oxidizing bacteria induced by iron-carbon micro-electrolysis according to claim 9, characterized in that, To maintain the long-term operation of the system, 10% of the iron-based packing is replenished every quarter, activated carbon is regenerated by sun exposure every year, and the zeolite packing is replaced when the antimony adsorption in the zeolite packing reaches 10-12 mg / g.

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