Culture method of sulfate-resistant efficient sulfate reducing flora

Abstract

The invention discloses a culture method of a sulfate-resistant efficient sulfate reducing flora. The culture method comprises the following steps: S1, preparing suspended filler balls and placing the suspended filler balls in a reactor filled with a culture solution; s2, sludge containing sulfate reducing bacteria is inoculated into the reactor; s3, performing sulfate-resistant domestication on the sulfate reducing flora to obtain a high-concentration sulfate-resistant sulfate reducing flora; wherein in the step S3, sulfate-resistant domestication is carried out on the sulfate reducing flora in the step S2 by adopting a method for increasing the sulfate concentration in a culture solution in a staged manner. The sulfate-resistant efficient sulfate flora cultured by the method is high in proportion of core functional bacteria and strong in biological activity, can remarkably improve the biochemical treatment removal rate of high-concentration sulfate wastewater, and is suitable for treating various types of wastewater with high-concentration sulfate.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment by microbial technology, and specifically relates to a method for culturing sulfate-resistant and highly efficient sulfate-reducing bacterial communities. Background Art

[0002] High-concentration sulfate has always been a typical characteristic of wastewater generated by industrial production, especially enterprises in heavy metal mining, printing and dyeing industries, etc. Sulfate is an important factor in water pollution. Excessive sulfate in water enters the underlying anaerobic environment and is converted into sulfide, accelerating the formation of black and odorous water bodies, weakening the water self-purification ability, deteriorating water quality and destroying the ecological balance of water bodies.

[0003] At present, in the existing technologies, the main treatment methods for sulfate wastewater include physical methods, chemical precipitation methods and biological methods. a. Physical methods mainly include ion exchange method, adsorption method, freeze crystallization method and membrane separation method. Physical methods have disadvantages such as strict reaction conditions, high operating costs and cumbersome operation steps, and their applications are also limited to some industries and fields. b. Chemical precipitation methods include barium salt precipitation method, calcium salt precipitation method and ettringite precipitation method. These methods all have potential hazards of secondary metal pollution and high requirements for operating conditions. c. The biological treatment of high-concentration sulfate wastewater generally includes aerobic / anaerobic biological treatment methods, mainly the anaerobic biological treatment method using sulfate-reducing bacteria. The biological method has been widely used due to its low treatment cost, good effect, no secondary pollution and strong applicability.

[0004] However, in wastewater such as acidic mine wastewater, there are often high concentrations of sulfate above 10,000 mg / L. The anaerobic biological treatment method using sulfate-reducing bacteria has limited tolerance to the concentration change of high-concentration sulfate in the SRB reactor, resulting in few applications of the true wastewater treatment process technology based on SRB. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a method for culturing sulfate-resistant and highly efficient sulfate-reducing bacterial communities.

[0006] The technical solution of the present invention is: a method for culturing sulfate-resistant and highly efficient sulfate-reducing bacterial communities, including the following steps:

[0007] S1. Fabricate suspended packing balls and place them in a reactor filled with culture solution;

[0008] S2. Inoculate the sludge containing sulfate-reducing bacteria into the reactor;

[0009] S3. Domesticate the sulfate-reducing bacterial community to be sulfate-resistant to obtain a sulfate-reducing bacterial community resistant to high-concentration sulfate;

[0010] S4. Determine the cultivation and domestication results of sulfate-resistant and highly efficient sulfate-reducing bacterial communities;

[0011] Among them, in S3, the sulfate-reducing bacterial community in S2 is domesticated for sulfate resistance by a method of gradually increasing the sulfate concentration in the culture medium. The method of gradually increasing the sulfate concentration in the culture medium is as follows: the domestication cycle of the sulfate bacterial community at each sulfate concentration stage is 6 - 8 days.

[0012] Furthermore, the preparation method of the suspended packing balls in S1 is as follows: Weigh 10 - 15 g of comet fiber packing and put it into a net-shaped suspended ball with a diameter of 80 mm; The suspended packing balls are loaded into the reactor to 60 - 80% of the effective volume of the reactor.

[0013] Note: In order to provide sufficient space for the growth and reproduction of the sulfate-reducing functional bacterial community and better attach to the comet fiber packing for metabolic activities, the volume occupied by the comet fiber packing-filled suspended balls is 40 - 60%.

[0014] Furthermore, the sludge containing sulfate-reducing bacteria in S2 is taken from the bottom mud in the tailings pond of a mining area with a high sulfide content, and the initial inoculation concentration is 3 - 5 g / L.

[0015] Furthermore, the pH of the culture medium in the reactor is controlled at 7.0 - 9.0, and the pH is adjusted by sodium carbonate; The composition of the culture medium is 1000 mg / L of sulfate, 2000 mg / L of COD (sodium lactate), maintaining the chemical oxygen demand (COD):SO4 2- ≈2:1, and it also contains 10 mg / L of P (potassium dihydrogen phosphate), 50 mg / L of N (ammonium chloride), maintaining COD∶N∶P≈200∶5∶1, and 1 mL / L of trace elements;

[0016] Among them, the composition of the trace element solution is: ZnSO4·7H2O: 0.50 ± 0.02 mg / L; NaMoO4·2H2O: 0.12 ± 0.005 mg / L; CoCl2·6H2O: 0.20 ± 0.01 mg / L; MnSO4·H2O: 0.50 ± 0.02 mg / L; NiCl2·6H2O: 0.70 ± 0.03 mg / L; CuSO4·5H2O: 0.60 ± 0.02 mg / L; FeSO4·7H2O: 5.00 ± 0.2 mg / L.

[0017] Note: The culture medium configured above can meet the cultivation requirements of sulfate-reducing bacteria, thereby realizing the efficient cultivation of sulfate-resistant and highly efficient sulfate-reducing bacterial communities.

[0018] Furthermore, the method for gradually increasing the sulfate concentration in the culture medium is as follows: the initial sulfate concentration of the culture medium is 1000 - 1200 mg / L, and the sulfate concentration of the culture medium is increased with a gradient of 1500 - 3500 mg / L, so that the final sulfate concentration of the culture medium is 11000 - 11200 mg / L.

[0019] Note: By increasing the sulfate concentration in a gradient manner, the toxicity of the accumulation of intermediate products (such as sulfide) caused by the introduction of high-concentration sulfate at one time to the sulfate-reducing bacterial community can be avoided. Gradually increasing the concentration in stages helps to maintain the dynamic balance between sulfide generation and subsequent oxidation reactions, thereby reducing the inhibition risk.

[0020] Furthermore, the reactor is a combined reactor of a continuous-flow downflow anaerobic reactor and an upflow anaerobic sludge reactor. A circulation pump is installed at the connection of the reactors, so that the ratio of the circulation flow rate to the influent flow rate is 1 - 3. The hydraulic retention time of the reactor is 20 - 24 h, and the temperature is 30 - 40 °C, which is controlled by a temperature controller and a spiral heating belt.

[0021] Note: The above combined reactor can meet the cultivation requirements of sulfate-reducing bacteria. Under the above ratio of the circulation flow rate to the influent flow rate, hydraulic retention time and temperature, an efficient sulfate-reducing bacterial community resistant to sulfate can be efficiently cultivated.

[0022] Furthermore, the sulfate is sodium sulfate, ammonium sulfate or a mixture of the two.

[0023] Note: When using the above agents to control the sulfate concentration in the culture medium and mixing the two, the specific concentration ratio depends on the sulfate concentration of the culture medium.

[0024] Even further, Fe3O4 superparamagnetic nanoparticles are doped into the comet fiber filler to form a magnetic-responsive fiber network;

[0025] And an array of electromagnetic coil groups is evenly embedded on the outer wall of the reactor. The circumferential spacing and the longitudinal spacing are both 40 - 60 mm. The diameter of a single coil is 50 mm, and the maximum magnetic field intensity of a single coil is 100 mT, supporting 0 - 100% gradient adjustment. And according to the position of the suspended packing balls, the array of electromagnetic coil groups is divided into an upper electromagnetic coil and a lower electromagnetic coil;

[0026] The gradient adjustment is regulated according to the sulfate concentration. Specifically, when the initial sulfate concentration of the culture solution is 1000 - 1200 mg / L, the array-type electromagnetic coil group is turned on, and the initial gradient value is 10 - 20%. For every 500 mg / L increase in the sulfate concentration, the gradient value increases by 10 - 15%. And when the gradient value reaches 100%, for every 500 mg / L increase in the sulfate concentration, the gradient value decreases by 1 - 5%. During this period, the switching period of the upper electromagnetic coil and the lower electromagnetic coil is 2 - 6 h / time.

[0027] Note: The above-mentioned comet fiber filler doped with superparamagnetic nanoparticles regulates the distribution density and arrangement direction of the fibers through an external magnetic field, realizes the dynamic adjustment of the pore structure, and by setting a gradient magnetic field generator, switches between the upper electromagnetic coil and the lower electromagnetic coil, and between the strong magnetic field and the weak magnetic field. The strong magnetic field makes the comet fiber filler closely arranged, and the weak magnetic field makes the comet fiber filler loosely distributed, which can assist in improving the biochemical treatment removal rate of high-concentration sulfate wastewater, thereby improving the domestication effect of sulfate-reducing bacteria in sulfate tolerance and increasing the biochemical treatment removal rate of high-concentration sulfate wastewater.

[0028] Furthermore, the method for doping superparamagnetic nanoparticles in the comet fiber filler is as follows:

[0029] 1) Using Fe3O4 superparamagnetic nanoparticles (particle size 20 - 50 nm), uniformly disperse them in the polyacrylonitrile PAN spinning solution by stirring for 24 h, and control the doping concentration of Fe3O4 superparamagnetic nanoparticles at 15 - 45 wt.%.

[0030] 2) Using a coaxial electrospinning device (voltage 20 kV, receiving distance 15 cm), with PAN as the core layer and magnetic particle - polyvinyl alcohol PVA as the shell layer, form magnetic fibers with a diameter of 3.5 - 5 μm, where the core layer thickness is 500 - 800 nm.

[0031] 3) After cutting the magnetic fibers into short fibers of 35 - 40 mm, spray a poly dopamine PDA coating with a thickness of 80 - 100 nm on the surface to obtain a comet fiber filler doped with superparamagnetic nanoparticles; (Test the saturation magnetization intensity (target value ≥ 30 emu / g) and magnetic field response speed (< 0.5 s) of the fibers through a vibrating sample magnetometer (VSM), that is, meet the requirements).

[0032] Note: Using the above method for doping superparamagnetic nanoparticles in the comet fiber filler can prepare a comet fiber filler with a Fe3O4 superparamagnetic nanoparticle doping amount of 15 - 45 wt.%, and the magnetic nanoparticles are uniformly dispersed in the comet fiber filler, which can well meet the use requirements of the comet fiber filler doped with superparamagnetic nanoparticles in the above method.

[0033] The beneficial effects of the present invention are as follows:

[0034] (1) In the present invention, the core functional bacteria of the sulfate-tolerant and highly efficient sulfate-reducing bacteria cultured have a high proportion and strong biological activity, which can significantly improve the biochemical treatment removal rate of high-concentration sulfate wastewater and are applicable to the treatment of various wastewater with high-concentration sulfate. Compared with the prior art, the sulfate-tolerant and highly efficient sulfate-reducing bacteria domesticated and cultured in the present invention can utilize a wide range of substrates, are easy to culture, have convenient operation, save a large amount of investment, and thus reduce the wastewater treatment cost. The domestication and culture method used in the present invention is applicable to large-scale and industrial production. The sulfate-reducing bacteria domesticated and cultured by the present invention can solve the problems of difficult biochemical treatment and high treatment cost of high-concentration sulfate wastewater, and have good economic and environmental benefits.

[0035] (2) The method of the present invention uses a continuous-flow down-flow anaerobic reactor + an up-flow anaerobic sludge reactor for cultivation, and gradually increases the sulfate concentration in the wastewater, enabling the low-activity sulfate-reducing bacteria in the tailings pond bottom sludge in the mining area to adapt to the high-concentration sulfate in the water, so as to achieve the purpose of efficiently treating sulfate in the water, thereby solving the treatment problem of high-concentration sulfate wastewater and having good economic and environmental benefits.

[0036] (3) In the present invention, the sulfate-tolerant and highly efficient sulfate-reducing bacteria cultured can utilize a wide range of substrates, and the cultivation operation is simple. Compared with physical, chemical and other methods, it reduces the wastewater treatment cost and is applicable to large-scale application. The sulfate-reducing bacteria cultured by the present invention can solve the problems of difficult biochemical treatment and high treatment cost of high-concentration sulfate wastewater, and bring more favorable basic conditions for production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic diagram of the reactor for the cultivation method of the present invention;

[0038] Figure 2 is a comparison diagram of the suspended packing balls before and after domestication and cultivation in the cultivation method of the present invention;

[0039] Among them, 1 - down-flow anaerobic reactor, 2 - up-flow anaerobic sludge reactor, 3 - culture solution inlet water tank, 4 - medicine inlet peristaltic pump, 5 - circulation pipeline, 6 - temperature controller, 7 - spiral heating belt, 8 - circulation pump, 9 - reactor support, 10 - outlet water tank, 11 - tail gas absorption device, 12 - comet fiber packing, 13 - suspended packing ball before domestication and cultivation, 14 - suspended packing ball after domestication and cultivation. DETAILED DESCRIPTION OF THE INVENTION

[0040] The following further detailed description of the present invention is made in conjunction with the specific embodiments to better reflect the advantages of the present invention.

[0041] Example 1: A method for culturing a sulfate-resistant and highly efficient sulfate-reducing bacterial community, comprising the following steps:

[0042] S1. Fabricate suspended packing balls and place them in a reactor filled with a culture solution;

[0043] Among them, the preparation method of the suspended packing balls in S1 is: Weigh 14 g of comet fiber packing and load it into a net-shaped suspended ball with a diameter of 80 mm; The suspended packing balls are loaded into the reactor to 80% of the effective volume of the reactor;

[0044] S2. Inoculate the sludge containing sulfate-reducing bacteria into the reactor; The sludge containing sulfate-reducing bacteria is taken from the bottom sludge in a tailings pond in a mining area with a high sulfide content, such as a copper sulfide mining area, and the initial inoculation concentration is 4 g / L;

[0045] Among them, the pH of the culture solution in the reactor is controlled at 8.0, and the pH is adjusted by sodium carbonate; The composition of the culture solution is 1000 mg / L of sodium sulfate, 2000 mg / L of COD (sodium lactate), maintaining the chemical oxygen demand (COD):SO4 2- ≈2:1, and also contains 10 mg / L of P (potassium dihydrogen phosphate), 50 mg / L of N (ammonium chloride), maintaining COD∶N∶P≈200∶5∶1, and 1 mL / L of trace elements; The composition of the trace element solution: ZnSO4·7H2O: 0.50 mg / L; NaMoO4·2H2O: 0.12 mg / L; CoCl2·6H2O: 0.20 mg / L; MnSO4·H2O: 0.50 mg / L; NiCl2·6H2O: 0.70 mg / L; CuSO4·5H2O: 0.60 mg / L; FeSO4·7H2O: 5.00 mg / L;

[0046] S3. Domesticate the sulfate-reducing bacterial community to be sulfate-resistant to obtain a sulfate-reducing bacterial community resistant to high-concentration sulfate; S3 uses a method of gradually increasing the sulfate concentration in the culture solution to domesticate the sulfate-reducing bacterial community in S2 to be sulfate-resistant. The method of gradually increasing the sulfate concentration in the culture solution is: The initial sulfate concentration of the culture solution is 1132.32 mg / L, the increasing gradient of the sulfate concentration is 2500 mg / L, and the final sulfate concentration is 11497.2 mg / L. The domestication period of the sulfate bacterial community at each sulfate concentration stage is 7 d; Use sulfate to adjust the above sulfate concentration. Specifically, the sulfate is sodium sulfate, ammonium sulfate or a mixture of the two;

[0047] S4. Determine the cultivation and domestication results of the sulfate-resistant and highly efficient sulfate-reducing bacterial community. Specifically, after the domestication cultivation is completed, take the suspended packing balls in the reactor, wash out the sulfate-reducing bacterial sludge attached to the fiber filaments inside the balls with pure water, make a sample and conduct high-throughput sequencing. Determine whether the domestication process is completed by detecting the richness comparison of the sulfate-reducing bacterial community before and after domestication and the treatment effect on high-concentration sulfate wastewater through high-throughput sequencing technology. After the domestication is completed, it is known from the high-throughput sequencing technology detection report that the sulfate-reducing bacterial community in the sludge is mainly composed of Desulfomicrobium, and the incomplete-oxidation sulfate-reducing bacteria are the dominant bacteria. The proportion of the sulfate-reducing bacterial community mainly composed of Desulfomicrobium in the community before and after domestication increased from 58.68% to 94.08%. The treatment effect on high-concentration sulfate wastewater is that more than 90% of 11497.2 mg / L of sulfate is removed within 24 hours, achieving an ideal treatment effect. Therefore, it is considered that the domestication is completed;

[0048] In S3, the reactor is a combined reactor of a continuous downflow anaerobic reactor and an upflow anaerobic sludge reactor. As Figure 2 shown, load the suspended packing balls 2 into the reactor, and the loading amount is 80% of the effective volume of the reactor. Inoculate the bottom sludge of the mining area tailings pond at a concentration of 4 g / L into the downflow anaerobic reactor 1 and the upflow anaerobic sludge reactor 2 on the reactor support 9. Add the culture solution into the culture solution inlet water tank 3 of the reactor. Adjust the influent flow rate through the dosing peristaltic pump 4 to control the hydraulic retention time of the reactor to be 23 h. Use the temperature controller 6 and the spiral heating tape 7 to control the temperature at 35 °C. Use the circulation pump 9 and the circulation pipeline 5 to control the ratio of the circulation flow rate to the influent flow rate to be 2. The final effluent passing through the reactor enters Figure 1 the outlet water tank 10, and the H2S gas generated in the reactor is collected into the tail gas absorption device 11.

[0049] Example 2: The difference between this example and Example 1 is that the preparation method of the suspended packing balls in S1 is: weigh 10 g of comet fiber packing and load it into a net-shaped suspended ball with a diameter of 80 mm; the suspended packing balls are loaded into the reactor to 60% of the effective volume of the reactor.

[0050] Example 3: The difference between this example and Example 1 is that the preparation method of the suspended packing balls in S1 is: weigh 15 g of comet fiber packing and load it into a net-shaped suspended ball with a diameter of 80 mm; the suspended packing balls are loaded into the reactor to 70% of the effective volume of the reactor.

[0051] Example 4: The difference between this example and Example 1 is that the initial inoculation concentration is 3 g / L.

[0052] Example 5: The difference between this example and Example 1 is that the initial inoculation concentration is 5 g / L.

[0053] Example 6: The difference between this example and Example 1 is that the pH of the culture medium in the reactor is controlled at 7.0, and the pH is adjusted by sodium carbonate.

[0054] Example 7: The difference between this example and Example 1 is that the pH of the culture medium in the reactor is controlled at 9.0, and the pH is adjusted by sodium carbonate.

[0055] Example 8: The difference between this example and Example 1 is that the composition of the culture medium is 1000 mg / L of sodium sulfate, 2000 mg / L of COD (sodium lactate), maintaining the chemical oxygen demand (COD):SO4 2- ≈2:1, also containing 10 mg / L of P (potassium dihydrogen phosphate), 50 mg / L of N (ammonium chloride), maintaining COD∶N∶P≈200∶5∶1, and 1 mL / L of trace elements; the composition of the trace element solution: ZnSO4·7H2O: 0.48 mg / L; NaMoO4·2H2O: 0.115 mg / L; CoCl2·6H2O: 0.20±0.19 mg / L; MnSO4·H2O: 0.48 mg / L; NiCl2·6H2O: 0.67 mg / L; CuSO4·5H2O: 0.58 mg / L; FeSO4·7H2O: 4.8 mg / L.

[0056] Example 9: The difference between this example and Example 1 is that the composition of the culture medium is 1000 mg / L of sodium sulfate, 2000 mg / L of COD (sodium lactate), maintaining the chemical oxygen demand (COD):SO4 2- ≈2:1, also containing 10 mg / L of P (potassium dihydrogen phosphate), 50 mg / L of N (ammonium chloride), maintaining COD∶N∶P≈200∶5∶1, and 1 mL / L of trace elements; the composition of the trace element solution: ZnSO4·7H2O: 0.52 mg / L; NaMoO4·2H2O: 0.125 mg / L; CoCl2·6H2O: 0.21 mg / L; MnSO4·H2O: 0.52 mg / L; NiCl2·6H2O: 0.73 mg / L; CuSO4·5H2O: 0.62 mg / L; FeSO4·7H2O: 5.20 mg / L.

[0057] Example 10: The difference between this example and Example 1 is that the method for gradually increasing the sulfate concentration in the culture medium is as follows: the initial sulfate concentration of the culture medium is 1000 mg / L, and the sulfate concentration of the culture medium is increased using a sulfate concentration increasing gradient of 1500 mg / L, so that the final sulfate concentration of the culture medium is 11000 mg / L. The domestication period of the sulfate bacteria group at each sulfate concentration stage is 6 days.

[0058] Example 11: The difference between this example and Example 1 is that the method for gradually increasing the sulfate concentration in the culture medium is as follows: the initial sulfate concentration of the culture medium is 1200 mg / L, and the sulfate concentration of the culture medium is increased using a sulfate concentration increasing gradient of 3500 mg / L, so that the final sulfate concentration of the culture medium is 11200 mg / L. The domestication period of the sulfate bacteria group at each sulfate concentration stage is 8 days.

[0059] Example 12: The difference between this example and Example 1 is that a thermostat 6 and a spiral heating tape 7 are used to control the temperature at 30 °C.

[0060] Example 13: The difference between this example and Example 1 is that a thermostat 6 and a spiral heating tape 7 are used to control the temperature at 40 °C.

[0061] Example 14: The difference between this example and Example 1 is that the bottom mud of the mining area tailings pond is inoculated onto the downflow anaerobic reactor 1 and the upflow anaerobic sludge reactor 2 on the reactor support 9 at a concentration of 3 g / L. The culture medium is added to the culture medium inlet tank 3 of the reactor. The hydraulic retention time of the reactor is controlled by adjusting the influent flow rate with a dosing peristaltic pump 4 to be 20 h. A thermostat 6 and a spiral heating tape 7 are used to control the temperature at 35 °C. The ratio of the circulation flow rate to the influent flow rate is controlled to be 1 using a circulation pump 9 and a circulation pipeline 5. The final effluent passing through the reactor enters Figure 1 the outlet tank 10, and the H2S gas generated in the reactor is collected into the tail gas absorption device 11.

[0062] Example 15: The difference between this example and Example 1 is that the bottom mud of the mining area tailings pond is inoculated onto the downflow anaerobic reactor 1 and the upflow anaerobic sludge reactor 2 on the reactor support 9 at a concentration of 5 g / L. The culture medium is added to the culture medium inlet tank 3 of the reactor. The hydraulic retention time of the reactor is controlled by adjusting the influent flow rate with a dosing peristaltic pump 4 to be 24 h. A thermostat 6 and a spiral heating tape 7 are used to control the temperature at 35 °C. The ratio of the circulation flow rate to the influent flow rate is controlled to be 3 using a circulation pump 9 and a circulation pipeline 5. The final effluent passing through the reactor enters Figure 1 the outlet tank 10, and the H2S gas generated in the reactor is collected into the tail gas absorption device 11.

[0063] Example 16: The difference between this example and Example 1 is that superparamagnetic nanoparticles are doped into the comet fiber filler to form a magnetoresponsive fiber network; and an array of electromagnetic coils is uniformly embedded on the outer wall of the reactor, with a circumferential spacing and a longitudinal spacing of 50 mm, a single coil diameter of 50 mm, a maximum magnetic field intensity of 100 mT for a single coil, supporting 0 - 100% gradient adjustment, and the array of electromagnetic coils is divided into upper electromagnetic coils and lower electromagnetic coils according to the position of the suspended packing balls. Specifically, the upper electromagnetic coils refer to the array of electromagnetic coils embedded on the outer wall of the reactor above the horizontal position where the top of the suspended packing balls is located, and the lower electromagnetic coils are the array of electromagnetic coils embedded on the outer wall of the reactor below the horizontal position where the bottom of the suspended packing balls is located. The electromagnetic coils at each horizontal position can be marked as 1, 2, 3, 4,... from top to bottom for easy marking and control of the array of electromagnetic coils;

[0064] It should be noted that the electromagnetic coils can be replaced with electromagnets, and the electromagnets are arranged in the same distribution manner as above. Taking the reactor wall thickness of 5 cm in this example as an example, embedding means embedding to a depth of 4 cm inside the reactor side wall, that is, the distance between the electromagnetic coils and the inside of the reactor is 1 cm. However, this is not the only solution, and it can be set according to the actual reactor materials and electromagnetic coils used. The purpose is only to enable the electromagnetic coils to effectively act on the inside of the reactor;

[0065] The gradient adjustment is adjusted according to the sulfate concentration. Specifically, when the initial sulfate concentration of the culture solution is 1132.32 mg / L, the array of electromagnetic coils is turned on, and the initial gradient value is 16%. For every 500 mg / L increase in the sulfate concentration, the gradient value increases by 12%. And when the gradient value reaches 100%, for every 500 mg / L increase in the sulfate concentration, the gradient value decreases by 4%; during this period, the switching period of the upper electromagnetic coils and the lower electromagnetic coils is 4 h / time.

[0066] Among them, the method of doping Fe3O4 superparamagnetic nanoparticles into the comet fiber filler is as follows:

[0067] 1) Fe3O4 superparamagnetic nanoparticles (with a particle size of 20 - 50 nm) are uniformly dispersed in the polyacrylonitrile PAN spinning solution by stirring for 24 h, and the doping concentration of Fe3O4 superparamagnetic nanoparticles is controlled at 40 wt.%;

[0068] 2) Using a coaxial electrospinning device (voltage 20 kV, receiving distance 15 cm), with PAN as the core layer and magnetic particle - polyvinyl alcohol PVA as the shell layer, magnetic fibers with a diameter of 3.5 - 5 μm are formed, where the core layer thickness is 600 nm;

[0069] 3) After the magnetic fibers are cut into short fibers of 35-40 mm, a poly dopamine PDA coating with a thickness of 90 nm is sprayed on the surface to obtain a comet fiber filler doped with superparamagnetic nanoparticles; the saturation magnetization intensity (target value ≥ 30 emu / g) and the magnetic field response speed (< 0.5 s) of the fibers are tested by a vibrating sample magnetometer (VSM), that is, the requirements are met.

[0070] Example 17: The difference between this example and Example 14 is that an array of electromagnetic coils is arranged in the reactor with a spacing of 40 mm. When the initial sulfate concentration in the culture solution is 1132.32 mg / L, the array of electromagnetic coils is turned on, and the initial gradient value is 10%. For every 500 mg / L increase in the sulfate concentration, the gradient value increases by 10%. And when the gradient value reaches 100%, for every 500 mg / L increase in the sulfate concentration, the gradient value decreases by 1%. The switching period of the upper electromagnetic coil and the lower electromagnetic coil is 2 h / time.

[0071] Example 18: The difference between this example and Example 14 is that an array of electromagnetic coils is arranged in the reactor with a spacing of 60 mm. When the initial sulfate concentration in the culture solution is 1132.32 mg / L, the array of electromagnetic coils is turned on, and the initial gradient value is 20%. For every 500 mg / L increase in the sulfate concentration, the gradient value increases by 15%. And when the gradient value reaches 100%, for every 500 mg / L increase in the sulfate concentration, the gradient value decreases by 5%. The switching period of the upper electromagnetic coil and the lower electromagnetic coil is 6 h / time.

[0072] Example 19: The difference between this example and Example 14 is that the method of doping Fe3O4 superparamagnetic nanoparticles in the comet fiber filler is as follows: 1) Fe3O4 superparamagnetic nanoparticles (with a particle size of 20-50 nm) are evenly dispersed in the polyacrylonitrile PAN spinning solution by stirring for 24 h, and the doping concentration of Fe3O4 superparamagnetic nanoparticles is controlled at 15 wt.%; 2) Using a coaxial electrospinning device (voltage 20 kV, receiving distance 15 cm), with PAN as the core layer and magnetic particle-polyvinyl alcohol PVA as the shell layer, magnetic fibers with a diameter of 3.5-5 μm are formed, where the core layer thickness is 500 nm; 3) After the magnetic fibers are cut into short fibers of 35-40 mm, an 80 nm thick poly dopamine PDA coating is sprayed on the surface to obtain a comet fiber filler doped with superparamagnetic nanoparticles.

[0073] Example 20: The difference between this example and Example 14 is that the method of doping Fe3O4 superparamagnetic nanoparticles into the comet fiber filler is as follows: 1) Fe3O4 superparamagnetic nanoparticles (with a particle size of 20 - 50 nm) are uniformly dispersed in the polyacrylonitrile PAN spinning solution by stirring for 24 h, and the doping concentration of Fe3O4 superparamagnetic nanoparticles is controlled at 45 wt.%; 2) Using a coaxial electrospinning device (voltage 20 kV, receiving distance 15 cm), with PAN as the core layer and magnetic particle - polyvinyl alcohol PVA as the shell layer, magnetic fibers with a diameter of 3.5 - 5 μm are formed, where the core layer thickness is 800 nm; 3) After the magnetic fibers are cut into short fibers of 35 - 40 mm, a 100 - nm - thick polydopamine PDA coating is sprayed on the surface to obtain the comet fiber filler doped with superparamagnetic nanoparticles.

[0074] Application experimental example:

[0075] 1) The sulfate - resistant and highly efficient sulfate - reducing bacterial community of Example 1 was used to treat artificially prepared acidic mine wastewater. The water quality of the artificially prepared acidic mine wastewater using municipal tap water is shown in Table 1:

[0076] Table 1 Water quality of artificially prepared acidic mine wastewater

[0077]

[0078] Suspended packing balls containing the sulfate - resistant and highly efficient sulfate - reducing bacteria acclimated in the down - flow anaerobic reactor 1 were added to a sulfate reactor with an effective volume of 450 L until 80% of the reactor was effective. 450 ml of trace elements from the down - flow anaerobic reactor 1 were added to the reactor with the influent flow rate. The ratio of the recycle flow rate to the influent flow rate was adjusted to 2.5, the hydraulic retention time of the reactor was 24 h, and the temperature was controlled at 30 °C by a thermostat and a spiral heating belt. The sulfates, Cu 2+ and Mn 2+ in the reactor effluent were measured every day, and the removal rates were calculated. The test results showed that after the reactor had been operating for 15 days, the sulfate removal rate, Cu 2+ removal rate, and Mn 2+ removal rate reached 91.74%, 99.84%, and 89.74% respectively. The reactor operated continuously for 2 months, and the biochemical effect was stable.

[0079] 2) The sulfate - resistant and highly efficient sulfate - reducing bacterial community of Example 1 was used to treat actual acidic mine wastewater. The water quality of the actual acidic mine wastewater is shown in Table 2:

[0080] Table 2 Water quality of actual acidic mine wastewater

[0081]

[0082] A reactor with an effective volume of 2750 L was established, and the suspended packing balls containing the sulfate-resistant and highly efficient sulfate-reducing bacteria acclimated in the downflow anaerobic reactor 1 were added to the reactor until 80% of the effective volume of the reactor was filled. Since there is basically no COD and nutrients in the actual mine wastewater, COD, ammonium chloride, and potassium dihydrogen phosphate were added to the reactor along with the raw water flow to make COD / SO4 2- ≈2:1, COD∶N∶P≈200∶5∶1, and 2.75 L of trace elements in the downflow anaerobic reactor 1. A circulation pump was added to the reactor, and the ratio of the circulation flow to the influent flow was adjusted to 2.5. The hydraulic retention time of the reactor was 24 h, the water temperature was controlled at 30 °C, and the sulfates, Cu 2+ 、Mn 2+ 、Zn 2+ and Ni 2+ in the effluent of the reactor were measured every day. The removal rates were calculated. The detection results showed that after the reactor had been operating for 15 days, the sulfate removal rate, Cu 2+ 、Mn 2+ 、Zn 2+ and Ni 2+ removal rates reached 91.74%, 99.91%, 90.12%, 99.58% and 99.74% respectively. The reactor was continuously operated for 3 months, and the biochemical effect was stable.

[0083] 3) The sulfate-resistant and highly efficient sulfate-reducing bacteria communities in Examples 2 to 18 were used to treat the artificially prepared acidic mine wastewater. The suspended packing balls containing the sulfate-resistant and highly efficient sulfate-reducing bacteria acclimated in the downflow anaerobic reactor 1 of the above-mentioned methods of each example were added to the sulfate reactor with an effective volume of 450 L respectively. The sulfates in the effluent of the reactor were measured every day. After the reactor had been operating for 15 days, the sulfate removal rates were calculated as shown in Table 3:

[0084] Table 3 Sulfate removal rates of the artificially prepared acidic mine wastewater

[0085]

[0086]

[0087] The detection results showed that after the reactor had been operating for 15 days, the sulfate removal rates of each example reached over 85%, and the reactor was continuously operated for 3 months, and the biochemical effect was stable; however, there were differences in the sulfate removal effects of each example, and the specific analysis is as follows:

[0088] Analysis 1: Through the comparison of Example 2, Example 3 and Example 1, it was found that by adjusting the preparation method of the suspended packing balls and the filled effective volume, it had a certain impact on the sulfate removal rate of the acidic mine wastewater, and the preparation method of the suspended packing balls in Example 1 was the best;

[0089] Analysis 2: By comparing Example 4, Example 5 with Example 1, it is found that after adjusting the initial inoculation concentration, it has a certain impact on the sulfate removal rate of acid mine wastewater. Among them, the initial inoculation concentration of Example 1 is the optimal;

[0090] Analysis 3: By comparing Example 6, Example 7 with Example 1, it is found that after adjusting the pH of the culture solution in the reactor inlet water, it has a certain impact on the sulfate removal rate of acid mine wastewater. Among them, the pH of the culture solution of Example 1 is the optimal;

[0091] Analysis 4: By comparing Example 8, Example 9 with Example 1, it is found that after adjusting the composition of the culture solution, it has a certain impact on the sulfate removal rate of acid mine wastewater. Among them, the composition of the culture solution of Example 1 is the optimal;

[0092] Analysis 5: By comparing Example 10, Example 11 with Example 1, it is found that after adjusting the method of gradually increasing the sulfate concentration in the culture solution, it has a certain impact on the sulfate removal rate of acid mine wastewater. Among them, the method of increasing the sulfate concentration in the culture solution of Example 1 is the optimal;

[0093] Analysis 6: By comparing Example 12, Example 13 with Example 1, it is found that after adjusting the temperature value of the reactor, it has a certain impact on the sulfate removal rate of acid mine wastewater. Among them, the temperature value of Example 1 is the optimal;

[0094] Analysis 7: By comparing Example 14, Example 15 with Example 1, it is found that after adjusting parameters such as the ratio of the recycle flow rate to the influent flow rate and the hydraulic retention time of the reactor, it has a certain impact on the sulfate removal rate of acid mine wastewater. Among them, the reactor parameters of Example 15 are the optimal. However, after comparing with Example 1, it is found that the improvement effect of Example 15 compared with Example 1 is not obvious, and the initial parameter requirements of the reactor in Example 15 are higher, resulting in a higher cultivation cost. Therefore, from the perspectives of economy, time, etc., the reactor parameters of Example 1 are relatively optimal;

[0095] Analysis 8: By comparing Example 16 with Example 1, it is found that after using the comet fiber filler doped with superparamagnetic nanoparticles and the gradient adjustment method, the sulfate removal rate of acid mine wastewater is increased from 91.74% to 98.22%. It can be seen that this method improves the domestication effect of sulfate-reducing bacteria in sulfate resistance, and then improves the biochemical treatment removal rate of high-concentration sulfate wastewater;

[0096] Analysis 9: It is found by comparing Example 17, Example 18 with Example 16 that after adjusting the parameters of the gradient adjustment method, it has a certain impact on the sulfate removal rate of acidic mine wastewater, and the parameters of the gradient adjustment method in Example 16 are the optimal;

[0097] Analysis 10: It is found by comparing Example 19, Example 20 with Example 16 that after adjusting the method of doping Fe3O4 superparamagnetic nanoparticles in the comet fiber packing, it has a certain impact on the sulfate removal rate of acidic mine wastewater, and the doping concentration of Fe3O4 superparamagnetic nanoparticles in Example 16 is the optimal.

Claims

1. A method for culturing a sulfate-resistant and highly efficient sulfate-reducing bacterial community, characterized in that, It includes the following steps: S1. Fabricate suspended packing balls and place them in a reactor filled with culture medium; S2. Inoculate the sludge containing sulfate-reducing bacteria into the reactor; S3. Domesticate the sulfate-reducing bacteria group to be sulfate-tolerant to obtain a sulfate-reducing bacteria group tolerant to high-concentration sulfate; Among them, in S3, the method of gradually increasing the sulfate concentration in the culture medium is used to domesticate the sulfate-reducing bacteria group in S2 to be sulfate-tolerant. The method of gradually increasing the sulfate concentration in the culture medium is: the domestication period of the sulfate bacteria group at each sulfate concentration stage is 6 - 8 d.

2. The culturing method of a sulfate-resistant and highly efficient sulfate-reducing bacterial community according to claim 1, wherein The preparation method of the suspended packing balls in S1 is: weigh 10 - 15 g of comet fiber packing and put it into a net-shaped suspended ball with a diameter of 80 mm; the suspended packing balls are filled into the reactor to 60 - 80% of the effective volume of the reactor.

3. The culturing method of a sulfate-resistant and highly efficient sulfate-reducing bacterial community as described in claim 1, characterized in that, The sludge containing sulfate-reducing bacteria in S2 is taken from the bottom mud in the tailings pond of a mining area with a high sulfide content, and the initial inoculation concentration is 3 - 5 g / L.

4. The culturing method of a sulfate-resistant and highly efficient sulfate-reducing bacterial community according to claim 1, characterized in that, The pH of the culture medium in the reactor is controlled at 7.0 - 9.0, and the pH is adjusted with sodium carbonate; the composition of the culture medium is 1000 mg / L of sulfate, 2000 mg / L of sodium lactate, maintaining the chemical oxygen demand (COD):SO4 2- ≈2:1, and also contains 10 mg / L of potassium dihydrogen phosphate, 50 mg / L of ammonium chloride, maintaining COD∶N∶P≈200∶5∶1, and 1 mL / L of trace elements; Among them, the composition of the trace element solution is: ZnSO4·7H2O: 0.50 ± 0.02 mg / L; NaMoO4·2H2O: 0.12 ± 0.005 mg / L; CoCl2·6H2O: 0.20 ± 0.01 mg / L; MnSO4·H2O: 0.50 ± 0.02 mg / L; NiCl2·6H2O: 0.70 ± 0.03 mg / L; CuSO4·5H2O: 0.60 ± 0.02 mg / L; FeSO4·7H2O: 5.00 ± 0.2 mg / L.

5. The culturing method of a sulfate-resistant and highly efficient sulfate-reducing bacterial community according to claim 1, characterized in that, The method of gradually increasing the sulfate concentration in the culture medium is: the initial sulfate concentration of the culture medium is 1000 - 1200 mg / L, and the sulfate concentration of the culture medium is increased by using a sulfate concentration increasing gradient of 1500 - 3500 mg / L, so that the final sulfate concentration of the culture medium is 11000 - 11200 mg / L.

6. The culturing method of a sulfate-resistant and highly efficient sulfate-reducing bacterial community as described in claim 1, characterized in that, The reactor is a combined reactor of a continuous down-flow anaerobic reactor and an up-flow anaerobic sludge reactor. A circulation pump is installed at the connection of the reactor to make the ratio of the circulation flow to the influent flow 1 - 3. The hydraulic retention time of the reactor is 20 - 24 h, and the temperature is 30 - 40 °C, which is controlled by a temperature controller and a spiral heating belt.

7. The culturing method of a sulfate-resistant and highly efficient sulfate-reducing bacterial community according to claim 4, characterized in that The pH of the culture medium is controlled at 7.0 - 9.0, and the sulfate is sodium sulfate, ammonium sulfate or a mixture of the two.

8. The culturing method of a sulfate-resistant and highly efficient sulfate-reducing bacterial community according to claim 2, characterized in that, Fe3O4 superparamagnetic nanoparticles are doped in the comet fiber packing to form a magnetic-responsive fiber network; And an array of electromagnetic coil groups is evenly embedded on the outer wall of the reactor. The circumferential spacing and the longitudinal spacing are both 40 - 60 mm. The diameter of a single coil is 50 mm, the maximum magnetic field intensity of a single coil is 100 mT, and it supports 0 - 100% gradient adjustment. And the array of electromagnetic coil groups is divided into an upper electromagnetic coil and a lower electromagnetic coil according to the position of the suspended packing balls. The gradient adjustment is adjusted according to the sulfate concentration. Specifically, when the initial sulfate concentration of the culture solution is 1000-1200 mg / L, the array-type electromagnetic coil group is turned on, and the initial gradient value is 10-20%. For every 500 mg / L increase in the sulfate concentration, the gradient value increases by 10-15%. And when the gradient value reaches 100%, for every 500 mg / L increase in the sulfate concentration, the gradient value decreases by 1-5%. During this period, the switching period of the upper electromagnetic coil and the lower electromagnetic coil is 2-6 h / time.

9. The culturing method of a sulfate-resistant and highly efficient sulfate-reducing bacterial community as described in claim 8, characterized in that, The method for doping superparamagnetic nanoparticles in the comet fiber filler is as follows: 1) Using Fe3O4 superparamagnetic nanoparticles, uniformly dispersed in the polyacrylonitrile PAN spinning solution by stirring for 24 h, and the doping concentration of the Fe3O4 superparamagnetic nanoparticles is controlled at 15-45 wt.%. 2) Using a coaxial electrospinning device, with PAN as the core layer and magnetic particle-polyvinyl alcohol PVA as the shell layer, to form magnetic fibers with a diameter of 3.5-5 μm, where the core layer thickness is 500-800 nm. 3) After the magnetic fibers are cut into short fibers of 35-40 mm, a polydopamine PDA coating with a thickness of 80-100 nm is sprayed on the surface to obtain a comet fiber filler doped with superparamagnetic nanoparticles.

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