A new process for treating beneficiation wastewater based on tailings pond

Abstract

This application relates to the field of wastewater treatment technology and discloses a novel process for treating mineral processing wastewater based on tailings ponds. The tailings pond is divided into three zones: Zone A (strong photocatalytic-disturbance reaction zone on the dry beach), Zone B (microbial synergistic refining zone at the tailings), and Zone C (anaerobic solidification / stabilization and heterotrophic co-metabolic decomposition zone 0.5-1.0 meters below the tailings sediment surface). In Zone A, semiconductor minerals present in situ in the tailings are utilized, and workshop wastewater is discharged with the tailings water to the tailings beach to form a thin water film for film-enhanced photocatalytic treatment. In Zone A, the tailings surface is periodically physically disturbed to activate the semiconductor mineral interface. In Zone B, dominant photosensitive microorganisms are inoculated and maintained for synergistic refining. In Zone C, dominant sulfate-reducing bacteria are inoculated and maintained to enhance the solidification / stabilization of heavy metals. This invention solves the problems of in-situ catalyst passivation and water light attenuation, achieving efficient and long-term stable removal of pollutants from mineral processing wastewater.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically a new process for treating mineral processing wastewater based on tailings ponds. Background Technology

[0002] Mineral processing wastewater is one of the major sources of pollution in mining production, characterized by high concentrations of heavy metal ions (such as molybdenum and copper) and complex organic mineral processing reagents. Direct discharge of this type of wastewater poses a serious threat to the ecological environment. Tailings ponds, as traditional disposal sites for mineral processing wastewater, have limited purification capacity, leading to long-term accumulation of pollutants within the pond area and significant environmental risks.

[0003] Currently, attempts at in-situ remediation of tailings ponds face multiple technical bottlenecks. On the one hand, processes relying on natural attenuation or conventional biological treatment (such as wetland construction) exhibit highly unstable treatment effects when faced with the dual stresses of high biotoxicity (heavy metal ions) and high chemical stability (recalcitrant organic matter) in mineral processing wastewater. Microbial activity is easily inhibited, making it difficult to achieve continuous removal of pollutants. This highlights the limitations of single treatment technologies in dealing with complex wastewater.

[0004] On the other hand, existing research has recognized that some tailings (such as those containing pyrite) possess semiconductor properties and have the potential for photocatalytic degradation of pollutants. However, there are two insurmountable obstacles to translating this potential into practical engineering applications. First, tailings ponds are typically deep water bodies, where sunlight (especially ultraviolet light) has extremely limited penetration depth, resulting in very low light energy utilization. The vast majority of semiconductor minerals in the water are in an ineffective state due to insufficient light exposure, a bottleneck in reaction efficiency caused by light attenuation. Second, even at the water surface or on the beach, the catalytic activity of mineral particles cannot be maintained for long. During the reaction, intermediate products of organic matter degradation, heavy metal hydroxide precipitates, and microbial secretions rapidly deposit and cover the mineral surface, forming a passivation layer that hinders the exposure of active sites and photon absorption, leading to catalyst deactivation and a rapid decline in treatment efficiency over time.

[0005] Therefore, existing technologies generally lack an integrated process that can efficiently utilize in-situ tailings resources, overcome light decay limitations, and solve the long-term stability problem of catalysts, thus failing to achieve economical, efficient, and stable treatment of complex mineral processing wastewater. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a novel process for treating mineral processing wastewater based on tailings ponds. This process solves the problems of low pollutant removal efficiency and inability to operate stably for long periods when using tailings ponds to treat mineral processing wastewater, due to water light decay and in-situ catalyst passivation and deactivation.

[0007] To achieve the above objectives, the present invention provides a novel process for treating mineral processing wastewater based on tailings ponds, comprising the following steps:

[0008] S1. The tailings pond is functionally divided into Zone A, Zone B, and Zone C. Zone A is a strong photocatalytic-disturbance reaction zone for the dry tailings; Zone B is a microbial synergistic refining zone for the tailings; and Zone C is an anaerobic solidification / stabilization zone 0.5-1.0 meters below the tailings sediment surface. Zone A utilizes the semiconductor minerals present in situ in the tailings, while Zone C utilizes the anaerobic reduction environment 0.5-1.0 meters below the tailings sediment surface to enhance the solidification / stabilization of heavy metals.

[0009] S2. Perform thin-film enhanced photocatalytic treatment in area A, the treatment including the discharge of workshop wastewater with tailings water to the tailings beach to form a thin water film;

[0010] S3. Activate the semiconductor mineral interface in the A region, wherein the activation includes periodically physically disturbing the tailings surface layer.

[0011] S4. The mineral processing wastewater treated in zone A is flowed by gravity to zones B and C, and synergistic refining is carried out in zone B. The refining process includes inoculating and maintaining dominant photosensitive microorganisms, solidifying / stabilizing heavy metals in zone C, and co-metabolizing and decomposing flotation reagents through the non-specific action of microbial enzymes.

[0012] By adopting the above technical solution, this process achieves synergistic and efficient removal of organic pollutants and heavy metal ions from mineral processing wastewater by constructing a multifunctional zoned system and synergistically integrating thin-film enhanced photocatalysis, semiconductor mineral interface activation, and superior photosensitive microbial refining technology within each functional zone, as well as sulfate-reducing anaerobic bacteria solidification / stabilization and non-specific co-metabolic decomposition by microbial enzyme systems. It also solves the problems of low efficiency, poor stability, and easy pollution associated with traditional tailings ponds, thus obtaining a highly efficient, stable, and environmentally friendly mineral processing wastewater treatment effect.

[0013] Preferably, the volume ratio of Zone A, Zone B, and Zone C is 1:(2-5):(10-400). By adopting the above technical solution, and adjusting the volume ratio of Zones A, B, and C, the hydraulic retention time allocation of the three treatment units can be optimized according to the initial pollution load, water quality composition, and expected effluent standards, thereby achieving a balance between treatment efficiency and operating costs. This volume ratio range ensures sufficient contact time to complete the initial degradation and fine removal of pollutants, while avoiding incomplete treatment caused by overloading or insufficient retention time in a single zone, thus improving the adaptability and operational economy of the entire treatment system.

[0014] Preferably, the thickness of the thin water film in step S2 is 0.5-5.0 cm, and the hydraulic load is 0.1-0.5 m. 3 / (m 2 (h) By adopting the above technical solution, a thin water film of considerable thickness is formed on the tailings beach surface, increasing the contact area between the water body and the tailings particles and the dry beach surface, and shortening the light penetration path in the water body, thus reducing light attenuation. This optimized parameter range allows sunlight (especially ultraviolet light) to irradiate the semiconductor minerals on the tailings surface more efficiently, thereby maximizing photocatalytic activity. Simultaneously, by controlling the hydraulic load, sufficient residence time is ensured for the wastewater in the film state to complete the photocatalytic reaction, avoiding short-circuit flow or incomplete reaction. The formation of the thin water film also promotes oxygen transport at the water-air interface, providing sufficient electron acceptors for oxidative degradation, further improving photocatalytic efficiency.

[0015] Preferably, the frequency of the periodic physical disturbance in step S3 is once every 12-48 hours, and the disturbance depth is 5-15 cm. By adopting the above technical solution, periodic physical disturbance in the strong photocatalytic disturbance reaction zone (Area A) can effectively solve the problem of passivation and deactivation of the photocatalyst (semiconductor minerals in tailings). During the photocatalytic process, the mineral surface gradually adsorbs reaction products, organic residues, or generates metal hydroxide precipitates, forming a passivation layer that hinders the exposure of active sites and the effective absorption of light energy. By controlling the disturbance frequency and depth, the mineral surface can be periodically renewed, adhering substances can be removed, and fresh, highly catalytically active mineral interfaces can be exposed. This operation not only maintains the long-term catalytic activity of the semiconductor minerals and prevents the decay of treatment efficiency, but also promotes the exchange of pollutants inside the tailings with the water, thereby improving the overall reaction rate.

[0016] Preferably, the hydraulic retention time (HRT) of zone A is 0.05-0.5 days, that of zone B is 2-4 days, and that of zone C is 5-10 days. By adopting the above technical solution, the HRTs of zones A, B, and C are set within the specified ranges, ensuring that each treatment unit has sufficient reaction time to achieve the expected treatment effect. The shorter HRT of zone A enables it to efficiently complete the initial photocatalytic oxidation and heavy metal complexation / precipitation of wastewater, reducing the load on subsequent treatment. The relatively longer HRT of zone B provides a stable environment and sufficient reaction time for the growth, metabolism, and synergistic fine treatment of dominant photosensitive microorganisms, especially for the biodegradation of slow organic matter and the biosorption / reduction of heavy metals. The relatively longer HRT of zone C provides a stable environment and sufficient reaction time for the growth, metabolism, and synergistic treatment of dominant sulfate-reducing bacteria and other anaerobic microorganisms, which is particularly crucial for the biodegradation of slow organic matter and the biosorption / reduction of heavy metals.

[0017] Preferably, the semiconductor mineral is pyrite and / or pyrrhotite, and the total mass percentage of the semiconductor mineral in the tailings is 1-10%. By adopting the above technical solution, the main semiconductor mineral components with photocatalytic activity in the tailings and their content range are clearly defined. Pyrite and pyrrhotite, as common sulfide minerals, can generate electron-hole pairs under light conditions, thereby initiating redox reactions, degrading organic pollutants, and changing the valence state of heavy metals. When their total mass percentage is within the range of 1-10%, the tailings material can provide sufficient active sites to support efficient photocatalytic reactions, while avoiding economic problems or potential secondary pollution risks caused by excessively high content. This limitation ensures that the utilized tailings material has stable and predictable catalytic performance.

[0018] Preferably, the dominant photosensitive microorganisms and sulfate-reducing bacteria, etc., anaerobic microorganisms mentioned in step S4 are photosensitive bacterial groups that are tolerant to molybdenum ions and / or copper ions, obtained through gradient acclimation to heavy metal ions in mineral processing wastewater. By adopting the above technical solution, the dominant photosensitive microorganisms and sulfate-reducing bacteria, etc., anaerobic microorganisms used in this process are not unscreened natural bacterial groups, but rather bacterial groups obtained through a gradient acclimation process, exhibiting high tolerance and activity to high concentrations of heavy metals (such as molybdenum ions and / or copper ions) in mineral processing wastewater. This acclimation process enables these bacterial groups to maintain highly efficient metabolic activity under heavy metal stress, carrying out biodegradation of organic pollutants and bioadsorption, bioreduction, or bioprecipitation of heavy metals. This customized microbial strategy enhances the treatment capacity and stability of the biological treatment unit for complex mineral processing wastewater pollutants, ensuring the effective operation of the microbial synergistic refining section.

[0019] Preferably, in step S4, the inoculation is a one-time addition of 5-10% (v / v) of the water volume in zone B; the maintenance is a supplementary addition of 1-2% (v / v) of the water volume in zone B every 15-30 days; the inoculation is a one-time addition of 5-10% (v / v) of the water volume in zone C; and the maintenance is a supplementary addition of 1-3% (v / v) of the water volume in zone C every 20-40 days. By adopting the above technical solution, the initial inoculation amount and periodic supplementation strategy of dominant photosensitive microorganisms and sulfate-reducing bacteria are precisely set to ensure that the number and activity of bacteria in the microbial synergistic treatment zones (zones B and C) are always in optimal working condition. A high initial inoculation ratio helps to quickly establish the dominant bacterial population and shorten the system start-up time. Regular small-dose supplementation can compensate for the natural decline or loss of the microbial community during long-term operation, maintain the biomass and genetic stability of the microbial community, resist the adverse effects of environmental changes, and thus ensure that the microbial treatment unit can remove pollutants in a long-term, continuous and efficient manner.

[0020] Preferably, the dominant photosensitive bacterial community is obtained through the following preparation steps: enriching and subculturing tailings pond sediment samples in a basic enrichment medium to obtain a mixed photosensitive bacterial culture; and subjecting the mixed photosensitive bacterial culture to gradient acclimatization in an acclimatization medium supplemented with heavy metal stressors to obtain the dominant photosensitive bacterial community.

[0021] The preparation method of the dominant photosensitive bacterial community used in this invention is described in detail using the above technical solution. This method begins with tailings pond sediment, a natural and environmentally adaptable source of bacteria. Through a systematic process of enrichment, subculturing, and gradient acclimatization, photosensitive bacterial communities with high tolerance and treatment capacity for target heavy metals are screened and cultivated from a complex microbial community. This preparation method ensures that the obtained bacterial community not only adapts to the tailings pond environment but also possesses the ability to specifically treat heavy metal pollutants in mineral processing wastewater, which is a key biological basis for ensuring the efficient operation of the entire process.

[0022] Preferably, the heavy metal stress agent is ammonium heptamolybdate and / or copper sulfate pentahydrate, and the final stress concentration of the gradient acclimation is 40-60 mg / L for Mo ions and / or 60-70 mg / L for Cu ions.

[0023] By adopting the above technical solution, the type of heavy metal stress agent used for acclimating the dominant photosensitive bacterial community and its final acclimation concentration were specifically defined. Ammonium heptamolybdate and copper sulfate pentahydrate are common molybdenum and copper compounds in mineral processing wastewater. Using them as stress agents ensures the targeted and effective acclimation of the bacterial community. Setting the final acclimation concentration in the range of 50-60 mg / L for Mo ions and / or 60-70 mg / L for Cu ions means that the screened dominant bacterial community has a high tolerance to these heavy metals. This high-concentration acclimation ensures that the bacterial community can survive stably and maintain its biological activity in actual mineral processing wastewater (which typically contains high concentrations of heavy metals), thereby effectively performing subsequent biological synergistic refining functions.

[0024] Preferably, the dominant sulfate-reducing anaerobic microbial community is obtained through the following preparation steps: enriching and subculturing tailings pond sediment samples in a basic enrichment medium to obtain mixed sulfate-reducing bacteria and other anaerobic microorganisms; and subjecting the mixed sulfate-reducing microbial community culture to gradient acclimatization in an acclimatization medium containing heavy metal stressors and flotation reagents to obtain the sulfate-reducing microbial community.

[0025] The preparation method of the sulfate-reducing bacterial community used in this invention is described in detail using the above technical solution. This method begins with tailings pond sediment, a natural and environmentally adaptable source of bacteria. Through a systematic process of enrichment, subculturing, and gradient acclimatization, sulfate-reducing bacterial communities with high tolerance and processing capacity to target heavy metals and flotation reagents are screened and cultivated from a complex microbial community. This preparation method ensures that the obtained bacterial community not only adapts to the tailings pond environment but also possesses the ability to specifically treat pollutants such as heavy metals and flotation reagents in mineral processing wastewater, which is a key biological basis for ensuring the efficient operation of the entire process.

[0026] Preferably, the heavy metal stress agent is ammonium heptamolybdate and / or copper sulfate pentahydrate, and the final stress concentration of the gradient acclimation is 30-40 mg / L for Mo ions and / or 50-60 mg / L for Cu ions. The flotation reagent is butyl xanthate and / or pentyl xanthate and / or No. 2 oil, and the final stress concentration of the gradient acclimation is 80-100 mg / L for butyl xanthate and / or 80-100 mg / L for pentyl xanthate, and 50-60 mg / L for No. 2 oil.

[0027] By adopting the above technical solution, the types of heavy metal stressors and flotation reagents used for acclimating the dominant sulfate-reducing bacteria, as well as their final acclimation concentrations, were specifically defined. Ammonium heptamolybdate and copper sulfate pentahydrate are common molybdenum and copper compounds in mineral processing wastewater. Their selection as stressors ensured the targeted and effective acclimation of the bacteria. Setting the final acclimation concentration in the range of 30-40 mg / L for Mo ions and / or 50-60 mg / L for Cu ions indicates that the selected dominant bacteria exhibit high tolerance to these heavy metals. This high-concentration acclimation ensures that the bacteria can stably survive and maintain biological activity in actual mineral processing wastewater environments (which typically contain high concentrations of heavy metals and flotation reagents), thereby effectively performing subsequent biological co-treatment functions.

[0028] This invention provides a novel process for treating mineral processing wastewater based on tailings ponds. It offers the following advantages:

[0029] 1. This invention divides the tailings pond into Zone A (strong photocatalytic disturbance reaction zone), Zone B (microbial synergistic refining zone), and Zone C (anaerobic reduction and heterotrophic co-metabolism decomposition zone).

[0030] 2. This invention achieves an optimized configuration of different treatment mechanisms. Zone A utilizes thin-film reinforcement and interface activation to achieve efficient non-biological pretreatment, rapidly degrading pollutants and reducing biotoxicity; Zone B utilizes dominant photosensitive microorganisms for deep biological refining. Zone C utilizes sulfate-reducing bacteria for heavy metal solidification / stabilization, and the non-specific action of microbial enzymes to co-metabolize and decompose flotation reagents. The three zones work synergistically in series and parallel, overcoming the limitations of single treatment technologies (such as photocatalysis or biological methods), and achieving synergistic and efficient removal of high concentrations of organic matter and heavy metals from mineral processing wastewater.

[0031] 3. This invention effectively solves the industry problem of easy passivation of semiconductor mineral surfaces when using in-situ tailings for photocatalysis by setting periodic physical disturbances in area A. Periodic disturbances can promptly remove reaction byproducts, precipitates, or microbial adhesions from the surface of mineral particles, continuously exposing fresh mineral interfaces with high catalytic activity. This overcomes the problem of reduced processing efficiency caused by the covering of active sites in traditional heterogeneous catalysis, ensuring the long-term stable operation of the entire process.

[0032] 4. This invention improves the efficiency of photocatalytic reactions by implementing thin-film enhanced photocatalysis in area A. This step involves pumping wastewater along with tailings to the tailings beach to form a thin water film, overcoming the problem of rapid light attenuation in water and allowing sunlight to maximally irradiate the semiconductor mineral surface. Simultaneously, the morphology of the thin water film significantly increases the water-air contact area, enhancing the mass transfer efficiency of oxygen (as the main electron acceptor in photocatalysis), thereby improving the rate and overall efficiency of photocatalytic degradation. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments and comparative examples. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] Preparation Examples 1-4:

[0035] Preparation Example 1: Preparation of concentrated solution of molybdenum-resistant dominant photosensitive bacteria (strain A)

[0036] (1) Preparation of basic enrichment medium: Prepare 1000 mL of basic enrichment medium. This medium uses tailings pond wastewater (such as the raw material portion) filtered through a 0.22 μm filter membrane as the solvent, and adds the following additional ingredients: sodium acetate 3.0 g, ammonium sulfate 1.0 g, dipotassium hydrogen phosphate 0.3 g, yeast extract 0.2 g, sodium chloride 0.8 g, and magnesium chloride 0.2 g. Adjust the pH of the medium to 7.0 using 1 mol / L NaOH and 1 mol / L HCl. Autoclave the prepared medium at 121 °C for 20 minutes and cool it for later use.

[0037] (2) Microbial enrichment: Take 10g (wet weight) of bottom sediment sample from the water-sludge interface of the tailings pond in the raw material part, inoculate it into a 1L anaerobic bottle containing 100mL of the above-mentioned sterile basic enrichment medium, and seal it. Place it in a light incubator and culture it continuously for 7 days at 25℃ and light intensity of 3000 lux.

[0038] (3) Subculturing and screening: Take 10 mL of the above enriched culture medium and transfer it to 100 mL of fresh sterile basic enrichment medium. Incubate under the same conditions for 7 days. Repeat this subculturing operation 5 times to obtain a preliminary enriched mixed photosensitive bacterial culture.

[0039] (4) Molybdenum tolerance acclimatization: Take the above enriched culture and inoculate it at a rate of 10% (v / v) onto a medium supplemented with ammonium heptamolybdate ((NH4)6Mo7O3). 24 The bacteria were cultured in an acclimatization medium containing 4H₂O, with an initial Mo ion concentration of 20 mg / L. The culture was carried out at 25°C and 3000 lux light. Subcultures were performed every 5-7 days at a 10% (v / v) inoculation rate, with the Mo ion concentration in the acclimatization medium successively increased to 30 mg / L, 40 mg / L, 50 mg / L, and 60 mg / L at each subculture. The bacterial population that stably grew in the acclimatization medium with a Mo ion concentration of 60 mg / L was identified as the dominant molybdenum-tolerant photosensitive bacterial population.

[0040] (5) Scale-up and concentration: The above-mentioned molybdenum-resistant dominant photosensitive bacterial group was inoculated into a 100L photobioreactor at a 5% (v / v) inoculation rate (the culture medium was a basal enrichment medium with additional ammonium heptamolybdate added to maintain the Mo ion concentration at 30 mg / L). The culture was scaled up at 25℃ and 3000 lux for 3-5 days. After the culture was completed, the culture was centrifuged at 8000 x g for 10 minutes, the supernatant was discarded, and the bacterial cells were collected. The bacterial cells were resuspended in sterile pH 7.0 phosphate buffer to achieve a final bacterial concentration (determined by cell counting) of 1.0 × 10⁻⁶. 9 cells / mL. This concentrate is strain A, and should be stored sealed at 4°C for later use.

[0041] Preparation Example 2: Preparation of Concentrated Solution of Copper-Tolerant Dominant Photosensitive Bacterial Strains (Strain B)

[0042] (1) Preparation of basic enrichment medium: Prepare 1000 mL of basic enrichment medium. This medium uses tailings pond wastewater (such as the raw material portion) filtered through a 0.22 μm filter membrane as the solvent, and adds the following additional ingredients: sodium acetate 3.0 g, ammonium sulfate 1.0 g, dipotassium hydrogen phosphate 0.3 g, yeast extract 0.2 g, sodium chloride 0.8 g, and magnesium chloride 0.2 g. Adjust the pH of the medium to 7.0 using 1 mol / L NaOH and 1 mol / L HCl. Autoclave the prepared medium at 121 °C for 20 minutes and cool it for later use.

[0043] (2) Microbial enrichment: Take 10g (wet weight) of bottom sediment sample from the water-sludge interface of the tailings pond in the raw material part, inoculate it into a 1L anaerobic bottle containing 100mL of the above-mentioned sterile basic enrichment medium, and seal it. Place it in a light incubator and culture it continuously for 7 days at 25℃ and light intensity of 3000 lux.

[0044] (3) Subculturing and screening: Take 10 mL of the above enriched culture medium and transfer it to 100 mL of fresh sterile basic enrichment medium. Continue to culture for 7 days at 25℃ and light intensity of 3000 lux. Repeat the above subculturing operation 5 times to obtain a preliminary enriched mixed photosensitive bacterial culture.

[0045] (4) Copper tolerance acclimatization: Take the above enriched culture and inoculate it at a 10% (v / v) inoculation rate into an acclimatization medium supplemented with copper sulfate pentahydrate (CuSO4·5H2O) to achieve an initial Cu ion concentration of 30 mg / L. Incubate at 25℃ and 3000 lux light. Subculture every 5-7 days at a 10% (v / v) inoculation rate, increasing the Cu ion concentration in the acclimatization medium to 40 mg / L, 50 mg / L, 60 mg / L, and 70 mg / L at each subculture. The bacterial population that stably grows in the acclimatization medium with a Cu ion concentration of 70 mg / L is the dominant copper-tolerant photosensitive bacterial population.

[0046] (5) Scale-up and concentration: The above-mentioned copper-tolerant dominant photosensitive bacteria were inoculated into a 100L photobioreactor at a 5% (v / v) inoculation rate (the culture medium was a basic enrichment medium, with additional copper sulfate pentahydrate added to maintain the Cu ion concentration at 40 mg / L). The culture was scaled up at 25℃ and 3000 lux for 3-5 days. After the culture was completed, centrifugation and concentration were performed using the same method as in step (5) of Preparation Example 1, so that the final bacterial concentration (determined by cell counting) reached 1.0 × 10⁻⁶. 9 cells / mL. This concentrate is strain B, and should be stored sealed at 4°C for later use.

[0047] Preparation Example 3: Preparation of concentrated solution of molybdenum-resistant dominant sulfate-reducing bacteria (strain C)

[0048] (1) Preparation of basic enrichment medium: Prepare 1000 mL of basic enrichment medium for sulfate-reducing bacteria. This medium uses tailings pond wastewater (such as the raw material portion) filtered through a 0.22 μm filter membrane as the solvent, and adds the following additional ingredients: Na2SO4 1.0 g, yeast extract 1.0 g, KH2PO4 0.5 g, CaCl2∙2H2O 2.0 g, MgSO4·7H2O 2.0 g, and sodium lactate 2.0 g. Adjust the pH of the medium to 7.0 using 1 mol / L NaOH and 1 mol / L HCl. Autoclave the prepared medium at 121 °C for 20 minutes, cool it, and then purge it with sterile nitrogen gas for deoxygenation.

[0049] (2) Microbial enrichment: Take 10g (wet weight) of bottom sediment sample from the tailings pond sedimentary beach below 1.0 meter from the raw material part, inoculate it into a 1L anaerobic bottle containing 100mL of the above-mentioned sterile basic enrichment medium, replace the air in the bottle with sterile nitrogen gas, and then seal it. Incubate continuously for 7 days at 25℃, in the dark, in a closed anaerobic environment.

[0050] (3) Subculturing and screening: Take 10 mL of the above enriched culture medium and transfer it to 100 mL of fresh, sterile sulfate-reducing bacteria basal enrichment medium. After purging the bottle with sterile nitrogen to replace the air, seal it and culture it for 7 days under anaerobic conditions at 25°C in the dark. Repeat this subculturing operation 5 times to obtain a preliminary enriched mixed sulfate-reducing bacteria culture.

[0051] (4) Molybdenum tolerance acclimatization: Take the above enriched culture and inoculate it at a 10% (v / v) inoculation rate into a medium supplemented with ammonium heptamolybdate ((NH4)6Mo7O3). 24 The initial Mo ion concentration in the acclimatization medium (·4H2O) was 20 mg / L. The medium was then cultured anaerobically in a closed system at 25°C without light. Subculture was performed every 5-7 days at a 10% (v / v) inoculation rate, with the Mo ion concentration in the acclimatization medium successively increased to 30 mg / L and 40 mg / L at each subculture. The bacterial population that stably grew in the acclimatization medium with a Mo ion concentration of 40 mg / L was identified as the dominant molybdenum-tolerant sulfate-reducing bacteria.

[0052] (5) Scale-up and concentration: The above-mentioned molybdenum-resistant dominant sulfate-reducing bacteria were inoculated into a 100L lightless anaerobic bioreactor at a 5% (v / v) inoculation rate (the culture medium was a basic enrichment medium, with additional ammonium heptamolybdate added to maintain the Mo ion concentration at 40 mg / L). The culture was scaled up for 5-7 days under lightless, sealed anaerobic conditions at 25℃. After the culture was completed, the culture was centrifuged at 8000 x g for 10 minutes, the supernatant was discarded, and the bacterial cells were collected. The bacterial cells were resuspended in sterile pH 7.0 phosphate buffer to achieve a final bacterial concentration (determined by cell counting) of 1.0 × 10⁻⁶. 9 cells / mL. This concentrate is strain C, and should be stored sealed at 4°C for later use.

[0053] Preparation Example 4: Preparation of concentrated solution of copper-resistant and flotation reagent-preferred sulfate-reducing bacterial strain (strain D)

[0054] (1) Preparation of basic enrichment medium: Prepare 1000 mL of sulfate-reducing bacteria basic enrichment medium. This medium uses tailings pond wastewater (such as the raw material portion) filtered through a 0.22 μm filter membrane as the solvent, and adds the following additional ingredients: Na2SO4 1.0 g, yeast extract 1.0 g, KH2PO4 0.5 g, CaCl2·2H2O 2.0 g, MgSO4·7H2O 2.0 g, and sodium lactate 2.0 g. Adjust the pH of the medium to 7.0 using 1 mol / L NaOH and 1 mol / L HCl. Autoclave the prepared medium at 121℃ for 20 minutes, cool it, and then purge it with sterile nitrogen gas for deoxygenation before use.

[0055] (2) Microbial enrichment: Take 10g (wet weight) of bottom sediment sample from the tailings pond sedimentary beach below 1.0 meter from the raw material part, inoculate it into a 1L anaerobic bottle containing 100mL of the above-mentioned sterile sulfate-reducing bacteria basic enrichment medium, replace the air in the bottle with sterile nitrogen gas, and then seal it. Incubate continuously for 7 days at 25℃, in the dark, in a closed anaerobic environment.

[0056] (3) Subculturing and screening: Take 10 mL of the above enriched culture medium and transfer it to 100 mL of fresh sterile sulfate-reducing bacteria basal enrichment medium. After purging the bottle with sterile nitrogen to replace the air, seal it and continue to culture it for 7 days under anaerobic conditions at 25°C in the dark. Repeat the above subculturing operation 5 times to obtain a preliminary enriched mixed sulfate-reducing bacteria culture.

[0057] (4) Acclimation to Copper and Flotation Agents: Take the above-mentioned enriched culture and inoculate it at a 10% (v / v) inoculation rate into an acclimation medium supplemented with copper sulfate pentahydrate (CuSO4·5H2O) and / or butyl xanthate and / or pentyl xanthate and / or No. 2 oil, based on the sulfate-reducing bacteria enrichment medium. The initial Cu ion concentration in the medium should be 30 mg / L and / or butyl xanthate concentration should be 50 mg / L and / or pentyl xanthate concentration should be 50 mg / L and / or No. 2 oil concentration should be 30 mg / L. Incubate at 25°C in a dark, sealed environment. Subculture every 5-7 days at a 10% (v / v) inoculation rate. At each subculture, sequentially increase the concentrations of Cu ions and / or butyl xanthate and / or pentyl xanthate and / or No. 2 oil in the acclimation medium to 40 mg / L and / or 80 mg / L and / or 80 mg / L and / or 40 mg / L, 50 mg / L and / or 90 mg / L and / or 90 mg / L and / or 50 mg / L, 60 mg / L and / or 110 mg / L and / or 110 mg / L and / or 60 mg / L. The bacterial population that stably grows in the acclimation medium with a Cu ion concentration of 60 mg / L, a butyl xanthate concentration of 110 mg / L, a pentyl xanthate concentration of 110 mg / L, and a No. 2 oil concentration of 60 mg / L is the copper-tolerant and flotation reagent-preferred sulfate-reducing bacterial population.

[0058] (5) Scale-up and concentration: The copper-tolerant and flotation reagent-preferred sulfate-reducing bacteria were inoculated at a rate of 5% (v / v) into a 100L lightless anaerobic bioreactor (the culture medium was a basic enrichment medium, with additional copper sulfate pentahydrate added to maintain the Cu ion concentration at 50 mg / L, butyl xanthate concentration at 80 mg / L, pentyl xanthate concentration at 80 mg / L, and No. 2 oil concentration at 50 mg / L). The culture was scaled up for 5-7 days under lightless, sealed anaerobic conditions at 25℃. After the culture was completed, centrifugation and concentration were performed using the same method as in step (5) of Preparation Example 1, to achieve a final bacterial concentration (determined by cell counting) of 1.0 × 10⁻⁶. 9 cells / mL. This concentrate is strain D, and should be stored sealed at 4°C for later use.

[0059] Examples 1-3:

[0060] Example 1:

[0061] This embodiment provides a mineral processing wastewater treatment process based on tailings ponds, including the following steps:

[0062] (1) Functional zoning and system construction: In a simulated tailings dam (total volume of 2500m³) 3In this process, HDPE flexible barriers from the raw material section are used to divide the storage area into three interconnected zones: (Zone A) a strong photocatalytic disturbance reaction zone, (Zone B) a microbial synergistic refining zone, and (Zone C) an anaerobic reduction and heterotrophic co-metabolism decomposition zone. Zone A has a volume of 100 m³. 3 The volume of Zone B is 200m³. 3 The volume of Zone C is 2200m³. 3 The volume ratio is 1:2:22. The thin-film reinforcement assembly and mineral activation assembly for the raw material section are installed in area A.

[0063] (2) Inoculation of dominant microorganisms: The concentrated solution of the molybdenum-resistant dominant photosensitive bacteria (strain A) prepared in Example 1 was added to the water body in area B in a single dose of 10 mg / L. 3 The inoculation ratio was 5% (v / v) of the effective volume of water in area B; a concentrated solution of the molybdenum-resistant dominant sulfate-reducing bacteria strain (strain C) prepared in Preparation Example 3 was added to water in area C in a single dose of 22m³. 3 This results in an inoculation rate of 1% (v / v) of the effective volume of water in Zone C.

[0064] (3) Process operation and photocatalytic enhancement: The beneficiation wastewater from the raw material section is treated at 333m³. 3 A continuous flow rate of / d is pumped into zone A, resulting in a hydraulic retention time (HRT) of 0.05 days. The float pump of the membrane reinforcement module is activated to pump the mineral processing wastewater from zone A to the surface of the tailings dry beach, where a continuous thin water film with a thickness of 1.0 cm is formed through a fan-shaped sprayer, with the hydraulic load controlled at 0.2 m. 3 / (m 2 The treated mineral processing wastewater flows back to the water body in area A by gravity.

[0065] (4) Semiconductor mineral interface activation: Every 24 hours after the start of the process, the mineral activation component in area A is activated, and the tailings at the bottom of area A are completely stirred by the underwater shallow rake system. The disturbance depth is set to 10cm and the operation lasts for 45 minutes.

[0066] (5) Microbial Refinement and Microbial Community Maintenance: The mineral processing wastewater treated in Zone A flows into Zone B through the guide port of the flexible screen. The hydraulic retention time (HRT) in Zone B is 2.0 days. Every 30 days from the start of process operation, 2m³ of microbial feedstock is added to Zone B. 3 The bacterial strain A (equivalent to 1% v / v of the volume of area B) is used to maintain the activity of the microbial community.

[0067] (6) Anaerobic Reduction / Stabilization and Heterotrophic Co-metabolic Decomposition and Microbial Community Maintenance: Part of the leachate generated in Zone A and part of the mineral processing wastewater after microbial treatment in Zone B flow into Zone C via seepage. The hydraulic retention time (HRT) in Zone C is 5.0 days. Every 30 days from the start of process operation, 11m³ of liquid is added to Zone C. 3 The microbial community activity is maintained by introducing strain C (equivalent to 0.5% v / v of zone C volume). Zone C utilizes the anaerobic reducing environment 0.5-1.0 meters below the tailings sediment surface to enhance the solidification / stabilization of heavy metals and promote the heterotrophic co-metabolic decomposition of flotation reagents through the non-specific action of anaerobic microbial enzyme systems.

[0068] Example 2:

[0069] This embodiment provides a mineral processing wastewater treatment process based on tailings ponds, including the following steps:

[0070] (1) Functional zoning and system construction: In a simulated tailings dam (total volume of 2500m³) 3 In this process, HDPE flexible barriers from the raw material section are used to divide the storage area into three interconnected zones: (Zone A) a strong photocatalytic disturbance reaction zone, (Zone B) a microbial synergistic refining zone, and (Zone C) an anaerobic reduction and heterotrophic co-metabolism decomposition zone. Zone A has a volume of 100 m³. 3 The volume of Zone B is 200m³. 3 The volume of Zone C is 2200m³. 3 The volume ratio is 1:2:22. The thin-film reinforcement assembly and mineral activation assembly for the raw material section are installed in area A.

[0071] (2) Inoculation of dominant microorganisms: The concentrated solution of the molybdenum-resistant dominant photosensitive bacteria (strain A) prepared in Example 1 was added to the water body in area B in a single dose of 10 mg / L. 3 The inoculation ratio was 5% (v / v) of the effective volume of water in area B; a concentrated solution of the molybdenum-resistant dominant sulfate-reducing bacteria strain (strain C) prepared in Preparation Example 3 was added to water in area C in a single dose of 22m³. 3 This results in an inoculation rate of 1% (v / v) of the effective volume of water in Zone C.

[0072] (3) Process operation and photocatalytic enhancement: The beneficiation wastewater from the raw material section is treated at 500m³. 3 A continuous flow rate of / d is pumped into zone A, ensuring a hydraulic retention time (HRT) of 0.5 days. The float pump of the membrane reinforcement module is activated to pump the mineral processing wastewater from zone A to the surface of the tailings dry beach, where a continuous thin water film of 0.5cm thickness is formed through fan-shaped sprayers, with the hydraulic load controlled at 0.4m. 3 / (m 2 The treated mineral processing wastewater flows back to the water body in area A by gravity.

[0073] (4) Semiconductor mineral interface activation: Every 12 hours after the start of the process, the mineral activation component in area A is activated, and the tailings at the bottom of area A are completely stirred by the underwater shallow rake system. The disturbance depth is set to 15cm and the operation lasts for 30 minutes.

[0074] (5) Microbial Refinement and Microbial Community Maintenance: The mineral processing wastewater treated in Zone A flows into Zone B through the guide port of the flexible screen. The hydraulic retention time (HRT) in Zone B is 3 days. Every 30 days from the start of process operation, 2m³ of microbial feed is added to Zone B. 3 The bacterial strain A (equivalent to 1% v / v of the volume of area B) is used to maintain the activity of the microbial community.

[0075] (6) Anaerobic Reduction / Stabilization and Heterotrophic Co-metabolic Decomposition and Microbial Community Maintenance: Part of the leachate generated in Zone A and part of the mineral processing wastewater after microbial treatment in Zone B flow into Zone C via seepage. The hydraulic retention time (HRT) in Zone C is 7.0 days. Every 30 days from the start of process operation, 11m³ of liquid is added to Zone C. 3 The microbial community activity is maintained by introducing strain C (equivalent to 0.5% v / v of zone C volume). Zone C utilizes the anaerobic reducing environment 0.5-1.0 meters below the tailings sediment surface to enhance the solidification / stabilization of heavy metals and promote the heterotrophic co-metabolic decomposition of flotation reagents through the non-specific action of anaerobic microbial enzyme systems.

[0076] Example 3:

[0077] This embodiment provides a mineral processing wastewater treatment process based on tailings ponds, including the following steps:

[0078] (1) Functional zoning and system construction: In a simulated tailings dam (total volume of 3000m³) 3 In this process, HDPE flexible barriers from the raw material section are used to divide the storage area into three interconnected zones: Zone A (a strong photocatalytic disturbance reaction zone), Zone B (a microbial synergistic refining zone), and Zone C (an anaerobic reduction and heterotrophic co-metabolism decomposition zone). Zone A has a volume of 30 m³. 3 The volume of Zone B is 150m³. 3 The volume of Zone C is 2820m³. 3 The volume ratio is 1:5:94. The thin-film reinforcement assembly and mineral activation assembly for the raw material section are installed in area A.

[0079] (2) Inoculation of dominant microorganisms: 3.75m³ of the concentrated solution of the molybdenum-resistant dominant photosensitive bacteria (strain A) prepared in Example 1 was added to the water body in area B in a single dose. 3 Simultaneously, 3.75 mL of the concentrated solution of the copper-resistant dominant photosensitive bacteria strain (strain B) prepared in Preparation Example 2 was added.3 The total dosage is 7.5m³. 3 This resulted in an inoculation ratio of 5% (v / v) of the effective volume of water in zone B. 14.1 m³ of the concentrated solution of the molybdenum-resistant dominant sulfate-reducing bacteria strain (strain C) prepared in Preparation Example 3 was added to the water in zone C in a single batch. 3 Simultaneously, 14.1 mg of the concentrated solution of the copper-resistant and flotation-preferred sulfate-reducing bacterial strain (strain D) prepared in Example 4 was added. 3 The total dosage was 28.2m³. 3 This results in an inoculation rate of 1% (v / v) of the effective volume of water in Zone C.

[0080] (3) Process operation and photocatalytic enhancement: The beneficiation wastewater from the raw material section is treated at 400m³. 3 A continuous flow rate of / d is pumped into Zone A, resulting in a hydraulic retention time (HRT) of 0.25 days. The float pump of the membrane reinforcement module is activated to pump the mineral processing wastewater from Zone A to the surface of the tailings dry beach, where a continuous thin water film of 1.5cm thickness is formed through fan-shaped sprayers, with the hydraulic load controlled at 0.3m. 3 / (m 2 The treated mineral processing wastewater flows back to the water body in area A by gravity.

[0081] (4) Semiconductor mineral interface activation: Every 36 hours after the start of the process, the mineral activation component in area A is activated, and the tailings at the bottom of area A are completely stirred by the underwater shallow rake system. The disturbance depth is set to 8cm and the operation lasts for 60 minutes.

[0082] (5) Microbial Refinement and Microbial Community Maintenance: The mineral processing wastewater treated in Zone A flows into Zone B through the guide port of the flexible grid. The hydraulic retention time (HRT) in Zone B is 3 days. From the start of process operation, every 15 days, 0.75 m³ of each of microbial strain A and microbial strain B are alternately added to Zone B. 3 (That is, the first time to add strain A, the second time to add strain B, and so on), the amount added each time is equivalent to 1% (v / v) of the volume of area B.

[0083] (6) Anaerobic reduction / stabilization and heterotrophic co-metabolism decomposition and microbial community maintenance: Part of the leachate generated in Zone A and part of the mineral processing wastewater after microbial treatment in Zone B flow into Zone C via seepage. The hydraulic retention time (HRT) in Zone C is 8.0 days. Every 30 days from the start of process operation, 7.05 m³ each of bacterial strains C and D are added to Zone C. 3(That is, the first replenishment is of strain C, the second replenishment is of strain D, and so on), with each replenishment amount equivalent to 0.5% (v / v) of the volume of zone C. Zone C utilizes the anaerobic reducing environment 0.5-1.0 meters below the tailings sedimentation surface to enhance the solidification / stabilization of heavy metals, and promotes the heterotrophic co-metabolic decomposition of flotation reagents through the non-specific action of anaerobic microbial enzyme systems.

[0084] Comparative Examples 1-5:

[0085] Comparative Example 1:

[0086] Compared with Example 1, the difference is that: no functional zoning is performed, no thin film reinforcement components and mineral activation components are constructed, no dominant microbial strains are inoculated, and the mineral processing wastewater is simply pumped into an unmodified simulated tailings pond and left to stand naturally.

[0087] Comparative Example 2:

[0088] Compared with Example 1, the difference is that the semiconductor mineral interface activation operation in step (4) is not performed, that is, the mineral activation component is not activated to periodically stir the tailings at the bottom of the reservoir. The remaining steps are the same as in Example 1.

[0089] Comparative Example 3:

[0090] Compared with Example 1, the difference is that the thin-film enhanced photocatalysis operation in step (3) is not performed, that is, the float pump is not started to pump the water in area A to the tailings beach to form a thin water film, and the wastewater is only treated in the water body in area A. The remaining steps are the same as in Example 1.

[0091] Comparative Example 4:

[0092] Compared with Example 1, the difference is that the dominant microbial inoculation operation in step (2) is not performed, nor are the microbial community maintenance operations in steps (5) and (6). That is, no exogenous microbial concentrate is added to areas B and C, and the treatment relies entirely on the original indigenous microorganisms in the tailings pond. The remaining steps are the same as in Example 1.

[0093] Comparative Example 5:

[0094] Compared to Example 1, the difference is that the anaerobic solidification / stabilization and heterotrophic co-metabolism decomposition zone C is not set up. Zones A and B are still operated under the conditions of Example 1, and the effluent after microbial synergistic treatment in Zone B is directly used as the final effluent. All other steps are the same as in Example 1.

[0095] Test Example 1-3:

[0096] Test Example 1: Feasibility Verification Experiment of Core Synergy

[0097] Experimental Objective: This experiment was conducted under controlled laboratory conditions to verify the synergistic effect among the four elements involved in this invention—semiconductor minerals (tailings), light, dominant photosensitive microorganisms, and sulfate-reducing bacteria—in the process of COD degradation and heavy metal removal, and to clarify that this effect is not a simple summation of the independent effects of each element.

[0098] Experimental steps:

[0099] Experimental system preparation: Prepare several 500mL sterile serum bottles, and fill each bottle with 250mL of experimental wastewater from the raw material section that has been filtered through a 0.45μm filter membrane.

[0100] Grouping: Five experimental groups were set up, with three parallel samples in each group.

[0101] Group A (dark adsorption control): 25g of tailings material from the raw material portion was added to the bottle, and the bottle was completely wrapped with aluminum foil to protect it from light.

[0102] Group B (Photocatalytic control): Add 25g of tailings material from the raw material portion to the bottle.

[0103] Group C (microbial control): 12.5 mL (i.e., 5% v / v inoculation volume) was inoculated into the bottle to prepare strain A prepared in Example 1.

[0104] Group D (physical mixing control): This group does not undergo direct reaction. Its data comes from the theoretical removal rate measured after mixing the supernatants of Group B and Group C, which have been running independently for 24 hours, at a volume ratio of 1:1.

[0105] Group E (synergistic system): Add 25g of tailings material from the raw material portion to the bottle, and simultaneously inoculate with 12.5mL (i.e., 5% v / v inoculation amount) to prepare strain A prepared in Example 1.

[0106] Reaction conditions: All reaction flasks except those in group A were placed in a light-illuminated shaker and continuously shaken at 25°C and 120 rpm. The light intensity was simulated using a full-spectrum lamp and set to 3000 lux.

[0107] Sampling and Analysis: Water samples were aseptically collected from each reaction flask at 0h, 6h, 12h, and 24h after the start of the reaction. After filtration through a 0.45μm microporous membrane, the concentrations of COD, Mo, and Cu in the supernatant were measured, and the removal rate was calculated.

[0108] Experimental results:

[0109] Table 1. Comparison of COD, Mo, and Cu removal rates in wastewater among different experimental groups (24h)

[0110] experimental group COD removal rate (%) Mo removal rate (%) Cu removal rate (%) Group A (Adsorption in the dark) 4.3 9.1 11.2 Group B (Photocatalysis) 21.5 18.2 24.6 Group C (Microorganisms) 16.8 26.5 22.1 Group D (Physical Mixture) 34.1 39.5 40.8 Group E (Collaborative System) 45.7 56.2 59.8

[0111] Results analysis:

[0112] Experimental data show that groups A, B, and C all exhibited certain pollutant removal capabilities, confirming the objective existence of physical adsorption, photocatalysis, and microbial degradation / adsorption in tailings. The removal rate of group D represents the linear superposition effect of photocatalysis and microbial action independently.

[0113] The key finding is that Group E (the synergistic system) achieved removal rates of 45.7% for COD, 56.2% for Mo, and 59.8% for Cu, all higher than those of Group D (physical mixture), which reached 34.1%, 39.5%, and 40.8%. This result clearly demonstrates that the coexistence of semiconductor minerals, light, and dominant photosensitive microorganisms results in a total pollutant removal effect exceeding the simple sum of the individual effects of each element, confirming a synergistic effect among the three.

[0114] The mechanism of this synergistic effect can be explained as follows: Under illumination, the photogenerated electrons and holes produced by the semiconductor minerals in the tailings can not only directly degrade some organic matter and change the valence state of heavy metals, but the strong oxidizing free radicals they generate can also decompose the recalcitrant large organic molecules in the wastewater into small organic acids that are easily utilized by microorganisms, providing microorganisms with a higher quality carbon source. Simultaneously, the metabolic activities of microorganisms (such as secreting extracellular polymeric substances, EPS) can complex heavy metal ions and effectively clean the surface of the mineral catalyst, preventing its deactivation, thereby maintaining and enhancing the overall treatment efficiency of the system. The experimental data in this study provide direct support for this synergistic mechanism.

[0115] Test Example 2: Comparison Test of the Effects of the Example and the Comparative Example

[0116] Comparison of pollutant removal efficiency:

[0117] Experimental objective: This experiment aims to quantify and compare the steady-state removal efficiency of the present invention's scheme (Examples 1-3) with different control schemes (Comparative Examples 1-4) under continuous operation conditions for major pollutants in mineral processing wastewater.

[0118] Experimental steps:

[0119] System setup and operation: Seven parallel simulated tailings dam treatment systems were built, with conditions completely identical to those in Examples 1-3 and Comparative Examples 1-4.

[0120] Continuous treatment: Each system treats the mineral processing wastewater from the raw material section and operates continuously and stably for 30 days in strict accordance with the process parameters and operating methods specified in their respective embodiments or comparative examples.

[0121] Sample Collection and Analysis: On the 30th day of system operation, water samples were collected from the final effluent of each system. The collected water samples were filtered through a 0.45 μm microporous membrane, and the concentrations of COD, Mo, and Cu in the filtrate were measured. Based on the pollutant concentrations in the influent (i.e., raw material wastewater) and effluent of each system, the overall removal rates of COD, Mo, and Cu for each scheme were calculated.

[0122] Experimental results:

[0123] Table 2. Total removal rate of pollutants after 30 days of operation in the examples and comparative examples

[0124] plan COD removal rate (%) Mo removal rate (%) Cu removal rate (%) Example 1 45.1 55.8 60.3 Example 2 48.7 59.2 63.8 Example 3 52.4 64.7 67.9 Comparative Example 1 6.8 10.1 12.5 Comparative Example 2 24.3 31.5 36.2 Comparative Example 3 28.1 35.8 40.1 Comparative Example 4 32.9 44.7 51.6

[0125] Results analysis:

[0126] The data in Table 2 show that the pollutant removal rates of Examples 1, 2, and 3 are all higher than those of all comparative examples.

[0127] Compared with Comparative Example 1 (natural decay), the removal rates of Examples 1-3 all showed orders of magnitude differences, confirming the necessity of the active, engineered treatment process provided by the present invention.

[0128] A comparison of the results of Example 1 and Comparative Example 2 shows that the lack of a semiconductor mineral interface activation step resulted in a decrease in the removal rates of COD, Mo, and Cu by approximately 20.8, 24.3, and 24.1 percentage points, respectively. This indicates that periodic physical perturbation is crucial for exposing mineral active sites, preventing catalyst surface passivation, and maintaining the long-term high efficiency of the system's photocatalytic activity.

[0129] A comparison of the results of Example 1 and Comparative Example 3 shows that the absence of the thin-film enhanced photocatalysis step resulted in a comprehensive decrease in pollutant removal rates. This demonstrates that increasing the effective reaction interface under light and the gas-liquid-solid three-phase mass transfer efficiency through thin-film formation is one of the core engineering methods to overcome light attenuation in water and achieve efficient photocatalytic degradation.

[0130] A comparison of the results of Example 1 and Comparative Example 4 shows that the lack of inoculation and maintenance by dominant microorganisms also reduced the pollutant removal rate, especially affecting the removal efficiency of Mo and Cu. This confirms that the screened and domesticated dominant microbial communities play a far greater role than untreated indigenous microbial communities in the deep transformation and fixation of pollutants, and are a necessary biological basis for achieving efficient synergistic treatment.

[0131] In summary, this invention integrates three key technological steps—semiconductor mineral interface activation, thin-film enhanced photocatalysis, and dominant microbial management—to construct an organic synergistic system whose overall processing performance surpasses any system lacking one or more of these key technological steps.

[0132] Test Example 3: Comparison of Long-Term Stability of Processing Technology

[0133] Experimental objective: This experiment aims to evaluate the performance stability of the process of the present invention under long-term continuous operation conditions, and to verify the decisive role of the semiconductor mineral interface activation step in maintaining the long-term processing efficiency of the system by comparing it with a comparative example that lacks a key step.

[0134] Experimental steps:

[0135] System operation: The two simulated tailings dam treatment systems described in Example 1 and Comparative Example 2 were run in parallel and continuously for 90 days under their respective set process parameters.

[0136] Periodic sampling: Starting from system startup (day 0), water samples are collected from the final outlets of the two systems every 10 days.

[0137] Performance index analysis: After pretreatment of the collected water samples, their COD concentration was measured, and the COD removal rate was calculated. The long-term stability of the two systems was compared by plotting the COD removal rate versus operating time.

[0138] Experimental results:

[0139] Table 3. Comparison of COD removal rates between Example 1 and Comparative Example 2 during 90 days of operation.

[0140] Running time (days) Example 1 COD removal rate (%) Comparative Example 2: COD Removal Rate (%) 10 44.5 42.1 20 45.3 34.7 30 45.1 24.3 40 44.9 21.5 50 45.5 18.2 60 45.2 16.8 70 44.7 15.1 80 44.8 14.6 90 45.0 14.2

[0141] Results analysis:

[0142] Table 3 provides a clear picture of the performance differences between the two systems during long-term operation. Example 1 maintained a high COD removal rate of 44%-46% throughout the 90-day test period, demonstrating excellent operational stability. In contrast, Comparative Example 2's COD removal rate was similar to Example 1 initially, but subsequently experienced a sustained and significant decline, dropping to 24.3% by day 30 and only 14.2% by day 90, indicating a severe degradation in system processing capacity.

[0143] This result reveals the intrinsic contribution of the semiconductor mineral interface activation step to process stability. In Comparative Example 2, due to the lack of periodic physical perturbation, byproducts of the photocatalytic reaction (such as metal hydroxide precipitation) and extracellular polymers generated by microbial metabolism gradually deposit and cover the surface of the tailings particles. This coating layer hinders the contact between the active sites of the semiconductor minerals and ultraviolet light and contaminants, leading to a sharp decline in the generation efficiency of photogenerated electron-hole pairs, i.e., catalyst passivation. The continuous decline in processing efficiency is a direct consequence of the accumulation of this surface passivation effect.

[0144] The periodic interface activation step included in Example 1 effectively removes the passivation layer on the mineral surface through mechanical disturbance, continuously exposing fresh, highly catalytically active mineral interfaces. This operation ensures that the photocatalytic reaction can proceed efficiently and for a long period, thereby enabling the entire treatment system to maintain stable pollutant removal performance. Therefore, this test confirms that semiconductor mineral interface activation is a key technical element for overcoming catalyst deactivation and ensuring the long-term stable operation of the process of this invention.

Claims

1. A novel process for treating mineral processing wastewater based on tailings ponds, characterized in that, Includes the following steps: S1. The tailings pond is functionally divided into Zone A, Zone B, and Zone C. Zone A is a strong photocatalytic-disturbance reaction zone for the dry beach; Zone B is a microbial synergistic refining zone for the tailings; and Zone C is an anaerobic solidification / stabilization zone and a heterotrophic co-metabolic decomposition zone 0.5-1.0 meters below the tailings sediment surface. Zone A utilizes the semiconductor minerals present in situ in the tailings, while Zone C utilizes the anaerobic reducing environment 0.5-1.0 meters below the tailings sediment surface to enhance the solidification / stabilization of heavy metals and promote the heterotrophic co-metabolic decomposition of flotation reagents through the non-specific action of anaerobic microbial enzyme systems. S2. Perform thin-film enhanced photocatalytic treatment in area A. The treatment includes discharging workshop wastewater with tailings water to the tailings beach and / or pumping mineral processing wastewater in area A to the surface of the dry tailings beach to form a thin water film. S3. Activate the semiconductor mineral interface in the A region, wherein the activation includes periodically physically disturbing the tailings surface layer. S4. The mineral processing wastewater treated in zone A is introduced into zone B, and synergistic refining is carried out in zone B. The refining includes inoculating and maintaining dominant photosensitive microorganisms. Part of the leachate generated in zone A and / or part of the mineral processing wastewater after microbial refining in zone B is seeped into zone C, where heavy metal solidification / stabilization and non-specific co-metabolism decomposition of flotation reagents by microbial enzymes are carried out.

2. The novel wastewater treatment process based on tailings dams according to claim 1, characterized in that, The volume ratio of area A, area B and area C is 1:(2-5):(10-400).

3. A novel wastewater treatment process based on a tailings dam according to claim 1, characterized in that, The thickness of the thin water film mentioned in step S2 is 0.5-5.0 cm, and the hydraulic load is 0.01-0.5 m. 3 / (m 2 ·h).

4. A novel wastewater treatment process based on a tailings dam according to claim 1, characterized in that, The frequency of the periodic physical disturbance in step S3 is once every 12-48 hours, and the disturbance depth is 5-15cm.

5. A novel wastewater treatment process based on tailings dams according to claim 1, characterized in that, The hydraulic residence time in zone A is 0.05-0.5 days, the hydraulic residence time in zone B is 2-4 days, and the hydraulic residence time in zone C is 5-10 days.

6. A novel wastewater treatment process based on a tailings dam according to claim 1, characterized in that, The semiconductor mineral is pyrite and / or pyrrhotite, and the semiconductor mineral accounts for 1-10% of the total mass of the tailings.

7. A novel wastewater treatment process based on a tailings dam according to claim 1, characterized in that, The dominant photosensitive microorganisms mentioned in step S4 are photosensitive bacterial groups that are tolerant to molybdenum ions and / or copper ions, obtained after being acclimated to the heavy metal ion gradient in mineral processing wastewater; the dominant sulfate-reducing anaerobic bacterial groups in zone C are anaerobic bacterial groups that are acclimated to the sulfate reduction of molybdenum ions and / or copper ions and / or flotation reagents, obtained after being acclimated to the heavy metal and flotation reagent gradient in mineral processing wastewater.

8. A novel process for treating mineral processing wastewater based on a tailings dam, as described in claim 1, is characterized in that, The inoculation of the dominant photosensitive microorganisms in zone B in step S4 is carried out in a single dose at a rate of 5-10% (v / v) of the water volume in zone B. The dominant photosensitive microorganisms in Zone B are maintained by adding 1-2% (v / v) of the water volume in Zone B every 15-30 days. In step S4, the dominant sulfate-reducing anaerobic bacteria in zone C are inoculated by adding 1-10% (v / v) of the water volume in zone C in a single dose. The dominant sulfate-reducing anaerobic bacteria in Zone C are maintained by adding 0.5-3% (v / v) of the water volume in Zone C every 20-40 days.

9. A novel wastewater treatment process based on a tailings dam according to claim 7, characterized in that, The dominant photosensitive bacterial community was obtained through the following preparation steps: Tailings pond sediment samples were enriched and passaged in a basic enrichment medium to obtain a mixed photosensitive bacterial culture. The mixed photosensitive bacterial culture was subjected to gradient acclimatization in an acclimatization medium supplemented with heavy metal stressors to obtain the dominant photosensitive bacterial group.

10. A novel process for treating mineral processing wastewater based on a tailings dam, as described in claim 7, is characterized in that... The dominant sulfate-reducing anaerobic bacterial community was obtained through the following preparation steps: The bottom sediment samples from 0.5-1.0 meters below the sedimentary beach surface of the tailings pond were enriched and passaged in a sulfate-reducing bacteria-based enrichment medium to obtain a mixed sulfate-reducing anaerobic bacterial culture. The mixed sulfate-reducing anaerobic bacterial culture was subjected to gradient acclimatization in an acclimatization medium supplemented with heavy metal stressors and / or flotation agents under dark, closed anaerobic conditions to obtain the dominant sulfate-reducing anaerobic bacterial community.

11. A novel process for treating mineral processing wastewater based on a tailings dam, as described in claim 9, is characterized in that, The heavy metal stress agent in step S2 is ammonium heptamolybdate and / or copper sulfate pentahydrate, and the final stress concentration of the gradient acclimation is 40-60 mg / L for Mo ions and / or 60-70 mg / L for Cu ions.

12. A novel process for treating mineral processing wastewater based on a tailings dam, as described in claim 10, is characterized in that, The heavy metal stress agent in step S4 is ammonium heptamolybdate and / or copper sulfate pentahydrate, and the final stress concentration of the gradient acclimation is 30-42 mg / L for Mo ions and / or 50-62 mg / L for Cu ions. The flotation reagent in step S4 is butyl xanthate and / or pentyl xanthate and / or No. 2 oil. The final stress concentration of the gradient acclimation is butyl xanthate concentration of 50-110 mg / L, and / or pentyl xanthate concentration of 50-110 mg / L, and No. 2 oil concentration of 30-60 mg / L.