High-salinity wastewater treatment method and system

Abstract

The invention belongs to the technical field of industrial wastewater treatment, and particularly relates to a treatment method and system for high-salinity (greater than 20g / L) and high-hardness (Ca greater than 500mg / L) wastewater. The wastewater is introduced into a bioreactor filled with a functional microbial capsule, and a preparation method of the capsule comprises the following steps: inoculating halotolerant bacteria into a culture medium containing NaCl and trehalose for culturing, mixing the prepared bacteria liquid with sodium alginate, and then dropwise adding a CaCl solution; immersing into a mixed solution containing polyaspartic acid and magnesium-aluminum hydrotalcite to form anti-scale microspheres; the preparation method comprises the following steps: adding carboxylated carbon nanotubes into an aniline phosphate buffer solution, dropwise adding ammonium persulfate, and depositing a polyaniline-carbon nanotube composite conductive layer on the peripheries of anti-scale microspheres; and finally, curing in a copolymer prepolymerization solution to form a responsive shell. According to the method disclosed by the invention, through combination of functionalized microbial capsules and staged salinity-electric field coordinated regulation and control, full-process optimization from strain domestication to stable operation is realized, and long-term stable treatment of high-salinity and high-hardness wastewater is realized.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of industrial wastewater treatment, and specifically provides a method and system for treating high-salt wastewater. Background Art

[0002] With the rapid development of industries such as oil extraction, chemical engineering, and pharmaceutical manufacturing, the discharge of high-salt and high-hardness wastewater has been increasing year by year. Due to the special physical and chemical properties of this type of wastewater, it is difficult for traditional treatment methods to achieve ideal treatment effects.

[0003] Currently, the treatment of high-salt and high-hardness wastewater mainly adopts physicochemical methods, biological methods, and combined processes. Although physicochemical methods such as reverse osmosis technology have certain desalination effects, they have problems such as high energy consumption and serious membrane fouling; although chemical precipitation methods can effectively remove hardness ions, the dosage of chemicals is large and a large amount of sludge will be generated. Due to the limited activity of microorganisms in a high-salt environment, the treatment efficiency of traditional biological treatment technologies is generally low.

[0004] The existing technologies mainly have the following technical problems: First, the high-salt environment causes the osmotic pressure imbalance inside microbial cells. When the salinity exceeds 30 g / L in the conventional activated sludge method, the microbial degradation efficiency will decrease by more than 60%; Second, high-concentration hardness ions such as Ca²⁺ and Mg²⁺ are likely to form inorganic scale layers in the reaction system, which will not only block the equipment pipelines but also cover the surface of microorganisms, seriously affecting the mass transfer efficiency; Third, existing anti-scaling technologies such as ultrasonic anti-scaling have problems such as poor frequency stability and high energy consumption, and chemical softening methods will cause secondary pollution.

[0005] Aiming at the deficiencies of the existing technologies, the present invention aims to provide an efficient and stable technical solution for treating high-salt and high-hardness wastewater. By constructing functionalized microbial capsules and combining staged salinity-electric field synergistic regulation, a complete high-salt and high-hardness wastewater treatment system is established to achieve long-term and stable treatment of high-salt and high-hardness wastewater. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technologies, one of the purposes of the present invention is to provide a method and system for treating high-salt wastewater by combining functionalized microbial capsules with staged salinity-electric field synergistic regulation, realizing the full-process optimization from strain domestication to stable operation, and achieving long-term and stable treatment of high-salt and high-hardness wastewater.

[0007] Technical Solution

[0008] To solve the above technical problems, the present invention provides a method and a treatment system for treating high-salt wastewater, which realizes stable and efficient treatment of high-salt wastewater by combining functionalized microbial capsules with a staged regulation strategy.

[0009] To solve the problem of microbial activity inhibition in high-salt environments, the core of the present invention lies in constructing functionalized microbial capsules with a specific structure and adopting a staged electrolysis strengthening strategy.

[0010] In a first aspect, the present invention provides a method for treating high-salt wastewater. The pretreated wastewater is introduced into a bioreactor filled with functionalized microbial capsules. The preparation of the functionalized microbial capsules is one of the core steps of this method. Specifically, the preparation method of the functionalized microbial capsules includes the following steps:

[0011] (1) Preparation of the salt-tolerant bacteria core: Inoculate salt-tolerant bacteria into a culture medium containing 125 - 150 g / L NaCl and 6.8 - 8.5 g / L trehalose for cultivation. Then mix the obtained bacterial solution with 3 - 5 wt% sodium alginate and drop it into a 1 - 3 wt% CaCl2 solution. The core microspheres are prepared by electrostatic forming. When the concentration of sodium alginate is lower than 3%, the mechanical strength is insufficient, and when it is higher than 5%, it hinders the diffusion of substrates. Controlling the curing temperature at 20 - 30 °C can balance the crosslinking speed and the survival rate of the bacteria. Experiments show that the survival rate of the bacteria can reach 92 - 95% when curing within this range.

[0012] (2) Construction of the anti-scaling layer: Immerse the core into a mixed solution containing 2 - 5 wt% polyaspartic acid and 0.5 - 1.5 wt% magnesium-aluminum hydrotalcite, and treat it at a temperature of 38 - 45 °C for 25 - 35 min to form anti-scaling microspheres. Treating at 38 - 45 °C for 25 - 35 min can enable polyaspartic acid to coordinate with the aluminum octahedron of the hydrotalcite through carboxyl groups to form a stable composite anti-scaling layer.

[0013] (3) Formation of the conductive layer: In an aniline phosphate buffer solution with a pH of 4.0 - 4.8, add 0.1 - 0.2 wt% carboxylated carbon nanotubes. Immerse the above anti-scaling microspheres and then add 0.4 - 0.6 wt% ammonium persulfate. A composite conductive layer of polyaniline-carbon nanotubes is deposited on the outer periphery of the anti-scaling microspheres by electrodeposition.

[0014] It is particularly noteworthy that a conductive layer with a volume resistivity ≤ 10 Ω·cm can be obtained by optimizing the deposition parameters. In the pH range of 4.0 - 4.8, aniline monomers exist in the cationic form and co-deposit with negatively charged carboxylated carbon nanotubes. When ammonium persulfate initiates polymerization, the carbon nanotubes can penetrate between the polyaniline chains to form a three-dimensional conductive network, reducing the volume resistivity to 8 - 10 Ω·cm.

[0015] (4) Coating with the responsive outer shell: Place the above capsule blanks in a copolymer prepolymer solution and cure them by ultraviolet light for a period of time. After forming a responsive outer shell with a thickness of 80 - 100 μm, the functionalized microbial capsules are obtained. The outer shell has a swelling degree of 150 - 200% when the pH > 8.5, and simultaneously releases nanometer montmorillonite. These nanosheets can adsorb on the surface of the bacteria to form a protective layer, alleviating the salinity shock.

[0016] Three monomers, N-isopropylacrylamide (NIPAM), methacrylic acid (MAA), and 2-hydroxyethyl acrylamide (HEA) with a molar ratio of (80 - 88):(8 - 12):(4 - 6) are mixed with 0.4 - 0.6 wt% of nanometer montmorillonite, and then a photoinitiator is added to prepare a copolymer prepolymer solution. The introduction of HEA can enhance the interfacial bonding force between the shell and the conductive layer, and the peel strength test shows that it reaches 15 - 18 N / cm².

[0017] Furthermore, to improve the salt tolerance acclimation efficiency of the bacterial community, the operation of the bioreactor adopts a three-stage progressive control strategy, which takes into account the adaptation requirements of microorganisms to changes in environmental conditions. During the adaptation period, the salt concentration of the salt-tolerant bacterial culture solution is gradually increased to 23 - 27 g / L at a gradient of 0.8 - 1.2 g / L per day under the condition of dissolved oxygen of 2.0 - 2.5 mg / L for 4 - 7 days, allowing the microorganisms to gradually adapt to the change in salt concentration. This speed is much faster than the traditional method (usually only 0.2 - 0.5 g / L / d), but combined with the slow-release protection mechanism of the functionalized capsule, the bacterial community can enter the highly active state without long-term adaptation. At the same time, the dissolved oxygen is controlled at 2.0 - 2.5 mg / L, which can not only meet the needs of most aerobic bacteria but also prevent the excessive consumption of carbon sources. More critically, when the turbidity fluctuation of the bacterial solution is monitored to be <5 - 8% and the intracellular Na⁺ / K⁺ ratio ≤0.2 - 0.4, it enters the intensification period.

[0018] During the intensification period, based on the salt concentration of 23 - 27 g / L, the combined action of a DC electric field of 0.4 - 0.6 V / cm and a pulsed electric field of 0.8 - 1.2 V / cm is applied, and at the same time, the salt concentration is continuously increased to 30 - 35 g / L. Particularly preferably, the frequency of the pulsed electric field is controlled at 0.8 - 1.2 Hz, and the duty cycle is 1:4 - 1:6, which can not only enhance electron transfer but also avoid cell damage. Among them, the DC electric field can stably maintain the membrane potential of the bacterial community, and the intermittent pulsed mode can prevent local pH imbalance caused by electrode polarization. At the same time, due to the presence of the conductive layer of the microbial capsule, the energy utilization rate of the applied electric field is greatly improved, and the desalination energy consumption is reduced by more than 30%.

[0019] More preferably, during the stable period, under the condition of salinity of 30-35 g / L, the cyclic maintenance strategy of "backwashing - ultrasonic treatment - seed crystal addition" is carried out daily. Specifically: first, backwash at a flow rate of 10-20 cm / s for 20-40 seconds, which can effectively remove the surface sediments without damaging the biofilm structure; then perform ultrasonic treatment for 8-12 minutes to prevent the accumulation of hardness ions on the carrier surface; and then add 80-120 mg / L of vaterite crystal seeds. It should be noted that controlling the backwash flow rate at 10-20 cm / s can effectively remove dead bacteria. Meanwhile, combined with ultrasonic treatment at 35-45 kHz and the addition of 80-120 mg / L of vaterite, the special lattice structure of vaterite can preferentially induce Ca²⁺ and Mg²⁺ to precipitate in the form of non-adhesive crystals. Combined with ultrasonic treatment at 35-45 kHz, the scale deposition amount in the reactor is reduced by 60-65%, enabling the system to operate stably for a long time under the high-salt condition of 30-35 g / L.

[0020] The trehalose is added at a concentration of 6-8 g / L during the bacterial culture stage and maintained at a final concentration of 3-5% by mass fraction during the solidification stage. Trehalose mainly enhances the short-term high-salt adaptation ability of microorganisms by regulating the osmotic pressure and activating salt-tolerant genes during the bacterial culture stage, increasing the bacterial survival rate from 30-40% to ≥90%; while during the solidification stage, it forms a stable three-dimensional gel network with sodium alginate-Ca 2+ to optimize the mechanical properties and long-term slow-release protection effect of the microspheres, so that the capsules still maintain more than 85% of the bacterial activity after 90 days of operation.

[0021] In the achievable mode of the first aspect, the layer spacing of the magnesium-aluminum hydrotalcite in the anti-scaling layer is 0.75-0.78 nm, the Ca²⁺ interception rate is ≥90% and the Na⁺ permeation rate is ≥85%. The layer spacing of the magnesium-aluminum hydrotalcite is designed to be 0.75-0.78 nm (measured by XRD). This size can selectively intercept >90% of Ca²⁺ and allow Na⁺ to pass freely, preventing calcium carbonate scale from blocking the pores of the capsules.

[0022] In the achievable mode of the first aspect, for the high-salt and high-hardness wastewater to be treated, purification treatment in the pretreatment stage is first carried out. The wastewater pretreatment includes the following steps:

[0023] Pass the wastewater through a vortex flocculator, control the linear velocity at 1.2±0.1 m / s, which can not only ensure the kinetic conditions for sufficient collision and growth of flocs, but also prevent the flocs from being broken due to too high a flow rate; simultaneously add 45-55 mg / L of polyacrylamide, so that the flocculant can effectively adsorb the fine particles in the water and form a stable floc structure.

[0024] The flocculated wastewater enters the filter screen for solid-liquid separation. The filter screen intercepts suspended solids and adjusts the pH to 7.5 - 8.0. More preferably, the surface of the filter screen is modified with perfluorooctyltriethoxysilane, and the static contact angle is greater than 120°, significantly improving the anti-fouling ability of the filter screen and ensuring that the flux decay rate is less than 5% per week.

[0025] When the online monitored Ca²⁺ concentration > 800 mg / L, 8 - 12 mg / L of polyaspartic acid is automatically added. The molecular weight of this polyaspartic acid is 3000 - 5000. This high molecular polymer can preferentially form soluble complexes with Ca²⁺, thus effectively inhibiting the scaling risk in the subsequent treatment unit.

[0026] In the implementable manner of the first aspect, it further includes a crystallization control stage. Through ultrasonic waves of 25 - 35 kHz and an ultrasonic power density of 0.4 - 0.6 W / cm³, combined with a hydrocyclone separator to dynamically remove Ca²⁺ deposits and achieve dynamic scale removal. By adjusting the centrifugal force field of the hydrocyclone separator, crystals with a particle size ≥ 10 μm can be efficiently separated. The recovered crystal seeds can be reused after cleaning, and the recycling utilization rate of the crystal seeds > 90%.

[0027] In the second aspect, the present invention provides a high-salt wastewater treatment system, which provides dedicated equipment support for implementing the above method. The system mainly includes a pretreatment unit, a bioreactor, and a crystallization control unit. The bioreactor is filled with functionalized microbial capsules with a volume ratio of 40 - 50%.

[0028] The microbial capsule achieves efficient desalination through a four-layer collaborative structure: the innermost layer is an alginate gel core embedding salt-tolerant bacteria. By adding trehalose and optimizing the CaCl₂ cross-linking concentration, the bacteria can maintain intracellular osmotic balance under high osmotic pressure. The selection of alginate concentration (3 - 5 wt%) ensures that the mechanical strength and mass transfer rate of the microspheres are at the best balance point. The intermediate anti-fouling layer is modified by compounding polyaspartic acid and magnesium-aluminum hydrotalcite. The special layered structure of hydrotalcite (layer spacing of 0.75 - 0.78 nm) can selectively adsorb Ca²⁺ without hindering the diffusion of Na⁺, thus avoiding the common fouling and blockage problems of traditional biological carriers. The outer conductive layer is composed of polyaniline-carbon nanotubes. The selective modification of carboxylated carbon nanotubes (0.1 - 0.2 wt%) can significantly reduce the electron transfer resistance, making the volume resistivity of the conductive layer lower than 10 Ω·cm, so as to efficiently promote the electron transfer efficiency of the bacterial community when an electric field is applied subsequently. In addition, to enhance the adaptability of the system, the outermost layer of the capsule is wrapped with a pH-responsive polymer, and this responsive polymer is composed of a copolymer of N-isopropylacrylamide, methacrylic acid, and hydroxyethyl acrylamide. When the environmental pH > 8.5 due to sudden changes in salinity, the swelling degree of the outer shell can increase by 150 - 200% and release nano-montmorillonite. This mineral particle can instantaneously bind free Na⁺, providing a buffer period for the bacterial community to activate the expression of salt-tolerant genes.

[0029] In an implementable manner of the second aspect, the system further includes:

[0030] A pretreatment unit, which includes a vortex flocculator. The vortex flocculation device is internally provided with a metal filter screen with a pore size of 45 - 55 μm, and the linear velocity of the vortex flocculator is controlled at 1.0 - 1.5 m / s;

[0031] A crystallization control unit, integrating a 28 - 40 kHz ultrasonic generator and a hydrocyclone separator, with a seed crystal recovery rate ≥ 90%. The underflow port of the hydrocyclone separator is connected to an automatic sludge discharge valve. When the sludge level sensor detects a height > 30 cm, sludge discharge is triggered, and the single sludge discharge volume < 5% of the volume of the hydrocyclone separator, which not only ensures the timely removal of sediments but also does not cause biomass loss.

[0032] In an implementable manner of the second aspect, the surface of the metal filter screen is coated with a polytetrafluoroethylene hydrophobic coating with a mass fraction of 0.1 - 0.3%, which can optimize the solid-liquid separation effect, reduce the risk of blockage, and extend the service life of the filter screen.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] (1) The present invention realizes multiple breakthroughs in the treatment of high-salt and high-hardness wastewater by constructing a four-layer structure of functionalized microbial capsules. The salt-tolerant bacteria core entraps salt-tolerant bacteria with sodium alginate as the matrix, adds trehalose to regulate osmotic pressure and activate salt-tolerant genes, increasing the survival rate of bacteria in a high-salt environment from 30% - 40% to ≥90%. Moreover, during the solidification stage, a stable gel network is formed with sodium alginate - Ca²⁺, ensuring that more than 85% of the bacterial activity remains after 90 days of operation; the anti-scaling layer is composed of a composite of polyaspartic acid and magnesium-aluminum hydrotalcite. The hydrotalcite with an interlayer spacing of 0.75 - 0.78 nm selectively intercepts ≥90% of Ca²⁺ while allowing ≥85% of Na⁺ to pass through, effectively preventing the blockage of capsule pores by calcium carbonate scale and solving the problem of mass transfer obstruction caused by scaling in high-hardness wastewater; the conductive layer forms a three-dimensional conductive network through the composite of polyaniline - carbon nanotubes, with a volume resistivity as low as ≤10Ω・cm. Under the action of an external electric field, the electron transfer efficiency is significantly improved, reducing the desalination energy consumption by more than 30%; the responsive outer shell has a swelling degree of 150% - 200% when pH > 8.5, releasing 50 - 80nm nano-montmorillonite to adsorb on the surface of bacteria to form a protective layer, alleviating the impact of sudden salinity changes. The four-layer structure acts synergistically to provide multiple protections for microorganisms, including salt tolerance, anti-scaling, conductivity, and environmental responsiveness.

[0035] (2) In the present invention, a phased salinity - electric field co-regulation strategy is adopted to significantly improve the treatment efficiency and stability of the bacterial community. During the adaptation period, a salinity increase gradient of 0.8 - 1.2g / L per day (4 times faster than the traditional method) is combined with dissolved oxygen control. Together with the slow-release protection mechanism of the functionalized capsule, the bacteria can enter a highly active state without long-term adaptation. The bacterial growth rate is ≥0.08 - 0.15h⁻¹. When the salinity reaches 23 - 27g / L, the turbidity fluctuation of the bacterial liquid is <5% - 8%, and the intracellular Na⁺ / K⁺ ratio is ≤0.2 - 0.4, ensuring the osmotic pressure balance of microorganisms; during the strengthening period, a DC electric field of 0.4 - 0.6V / cm and a pulsed electric field of 0.8 - 1.2V / cm are applied. The former stably maintains the membrane potential of the bacterial community, and the latter prevents local pH imbalance caused by electrode polarization. During the process of continuously increasing the salinity to 30 - 35g / L, the COD removal rate can be stably maintained above 85%; during the stable period, a maintenance cycle of "backwashing - ultrasonic treatment - seed addition" is performed daily. Backwashing removes surface deposits, ultrasonic treatment breaks up scaling particles, and vaterite crystal seeds induce the precipitation of Ca²⁺ and Mg²⁺ in the form of non-adhesive crystals, reducing the scale deposition amount in the reactor by 60% - 65% and achieving long-term stable operation under high-salt conditions.

[0036] (3) In the present invention, the pretreatment and crystallization control unit form an efficient auxiliary treatment system to ensure the stable operation of the main treatment unit. For wastewater pretreatment, the linear velocity is controlled at 1.2 ± 0.1 m / s through a vortex flocculator, and 45 - 55 mg / L of polyacrylamide is added to polymerize suspended solids into flocs with a size of ≥500 μm. After being intercepted by a metal filter screen, the removal rate reaches 95%. Meanwhile, when the online monitored Ca²⁺ concentration > 800 mg / L, 8 - 12 mg / L of polyaspartic acid is automatically added to complex free Ca²⁺ to inhibit scaling and reduce the treatment load of the anti-scaling layer; in the crystallization control stage, ultrasonic waves are used in combination with a hydrocyclone separator to destroy the growth of CaCO3 crystal nuclei and efficiently separate crystals with a particle size of ≥10 μm. The recycling rate of crystal seeds is > 90%, and Ca²⁺ deposits are dynamically removed, forming a dual anti-scaling mechanism of "internal barrier + external removal" with the anti-scaling layer, avoiding equipment blockage and secondary pollution, and prolonging the system operation cycle.

[0037] (4) In the present invention, the synergistic effect of the conductive layer of the microbial capsule and the applied external electric field is utilized to achieve efficient energy utilization and enhanced microbial metabolism. In an aniline phosphate buffer solution with a pH of 4.0 - 4.8, a polyaniline-carbon nanotube composite conductive layer is formed on the outer periphery of the anti-scaling microspheres through electrodeposition. The carboxylated carbon nanotubes penetrate between the polyaniline chains to form a three-dimensional conductive network, reducing the volume resistivity to 8 - 10 Ω·cm and significantly reducing the electron transfer resistance; under the action of the DC electric field and pulsed electric field applied during the enhancement period, the conductive layer efficiently conducts electric energy, stably maintains the membrane potential of the bacterial community and promotes electron transfer, enhancing the microbial metabolic activity. Compared with traditional methods, the desalination energy consumption is reduced by more than 30%. Moreover, the intermittent action of the pulsed electric field avoids electrode polarization and bacterial cell damage, ensuring the continuous and efficient degradation of pollutants by the bacterial community in a high-salt environment. The COD removal rate is increased by 30% compared with the traditional activated sludge method, reaching more than 85%.

[0038] (5) The present invention breaks through the bottleneck of traditional high-salt and high-hardness wastewater treatment and realizes the efficient and coordinated treatment of the whole process. Through the deep coupling of the four-layer structure of the functionalized microbial capsule and the staged regulation strategy, the problems of microbial osmotic pressure imbalance (the survival rate of bacterial cells ≥ 90%) in a high-salt environment, scaling and blockage caused by high-hardness ions, high energy consumption and low efficiency of traditional methods are solved. The salinity that can be treated reaches 30 - 35 g / L, the COD removal rate is stably at 85%, and the energy consumption is reduced to 0.9 kWh / m³; the pretreatment and crystallization control unit accurately removes suspended solids and dynamically controls scaling, enabling the bacterial activity to be maintained at 90% during 90 days of system operation, with a sludge production of only 0.1 kg / m³, and there is no need for frequent shutdown and cleaning. A complete system from water quality pretreatment, microbial enhancement to scaling control is constructed, providing a new solution for the long-term and stable treatment of industrial high-salt and high-hardness wastewater.

[0039] The present invention will be explained and described in detail below in conjunction with the accompanying drawings and specific embodiments. Description of the Drawings

[0040] Figure 1 It is a line graph of the COD removal rate in the wastewater treatment of Examples 1-3 and Comparative Examples 1-5 of the present invention;

[0041] Figure 2 It is a line graph of the cell survival rate in the wastewater treatment of Examples 1-3 and Comparative Examples 1-5 of the present invention;

[0042] Figure 3 It is a bar graph of the fouling amount in the wastewater system of Examples 1-3 and Comparative Examples 1-5 of the present invention. Detailed Embodiments

[0043] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant accompanying drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0045] Example 1: The embodiment of the present invention provides a method for treating high-salt wastewater, which includes the following steps:

[0046] I. Wastewater pretreatment: Pass the wastewater through a vortex flocculator, control the linear velocity at 1.2 m / s, synchronously add 50 mg / L of polyacrylamide (molecular weight 8 million), and the suspended solid particles with a diameter of ≤50 μm are polymerized into flocs with a diameter of ≥500 μm; then intercept the suspended solids through a metal filter screen and adjust the pH to 7.8, and the suspended solid removal rate reaches 95%; when the online monitored Ca²⁺ concentration > 800 mg / L, automatically add 10 mg / L of polyaspartic acid (molecular weight 4000), and the Ca²⁺ complexation rate is 88%.

[0047] II. Preparation of functionalized microbial capsules. The preparation method of the functionalized microbial capsules includes the following steps:

[0048] (1)Preparation of the inner core of salt-tolerant bacteria: Inoculate salt-tolerant bacteria into a medium containing 135 g / L NaCl and 7.5 g / L trehalose for cultivation. Mix the obtained bacterial solution with 4 wt% sodium alginate and then drop it into 2 wt% CaCl₂ solution. Prepare inner core microspheres by electrostatic forming, and solidify them at 25 °C for 2 h to form a shape. And the final concentration of trehalose in the solidification stage is 4%. The cell density in the prepared inner core microspheres is 1.2×10 9 CFU / mL, the cell survival rate is 94%, and the diameter of the inner core microspheres is (200±20) μm.

[0049] (2)Construction of the anti-scaling layer: Immerse the inner core into a mixed solution containing 3 wt% polyaspartic acid and 1.0 wt% magnesium-aluminum hydrotalcite. The layer spacing of magnesium-aluminum hydrotalcite is 0.76 nm. Treat it at 40 °C for 30 min to form an anti-scaling layer with a thickness of 40 μm, and obtain anti-scaling microspheres. The Ca²⁺ interception rate of the anti-scaling microspheres is 92%, and the Na⁺ permeability is 88%.

[0050] (3)Formation of the conductive layer: Add 0.15 wt% carboxylated carbon nanotubes to an aniline phosphate buffer solution with a pH of 4.5. Immerse the above anti-scaling microspheres and then drop 0.5 wt% ammonium persulfate. Form a composite conductive layer of polyaniline-carbon nanotubes with a volume resistivity of 9 Ω·cm on the outer periphery of the anti-scaling microspheres by electrodeposition.

[0051] (4)Coating with the responsive outer shell: Place the above capsule blank in the copolymer prepolymer solution and cure it by ultraviolet light for 30 min to form a responsive outer shell with a thickness of 90 μm, and obtain functionalized microbial capsules; the swelling degree of the responsive outer shell reaches 150-200% when pH>8.5, and the released nano-montmorillonite particles have a particle size of 50-80 nm.

[0052] Mix three monomers N-isopropylacrylamide (NIPAM), methacrylic acid (MAA), and 2-hydroxyethyl acrylamide (HEA) with a molar ratio of 85:10:5 and 0.5 wt% nano-montmorillonite, and then add a photoinitiator to prepare a copolymer prepolymer solution.

[0053] III. Phased operation of the bioreactor: Add the functionalized microbial capsules to the bioreactor, and pass the pretreated wastewater into the bioreactor for phased treatment:

[0054] Adaptation period (4 days): Under the condition of a dissolved oxygen of 2.3 mg / L, gradually increase the initial salinity from 18 g / L to 25 g / L at a gradient of 1.0 g / L per day for the salt-tolerant bacteria culture solution; Ensure that the cell growth rate ≥0.12 h⁻¹ by monitoring the cell density and survival rate. When the salinity reaches 25 g / L and the turbidity fluctuation of the bacterial solution <5% and the intracellular Na⁺ / K⁺ ratio ≤0.3, the adaptation period ends;

[0055] Enhanced period (7 days): Based on a salinity of 25 g / L, a DC electric field of 0.5 V / cm is applied in conjunction with a pulsed electric field of 1.0 V / cm. The frequency of the pulsed electric field is 1.0 Hz, and the duty cycle is 1:5. At the same time, the salinity is increased to 32 g / L at a rate of 1.0 g / L per day, and the COD removal rate is increased to 85%.

[0056] Stable period: Under the condition of a salinity of 32 g / L, a maintenance cycle of backwashing - ultrasonic - seed addition is performed daily. Specifically: First, backwash at a flow rate of 15 cm / s for 30 seconds, then perform ultrasonic treatment for 10 minutes, and then add 100 mg / L of vaterite seeds.

[0057] IV. Crystallization control stage, through ultrasonic waves of 28 kHz, a power density of 0.5 W / cm³, in conjunction with a hydrocyclone to dynamically remove Ca²⁺ deposits, and the seed circulation rate > 90%.

[0058] Ultrasonic waves: 28 kHz, power density 0.5 W / cm³, in conjunction with a hydrocyclone (automatically discharging sludge from the underflow port, triggered when the sludge level > 30 cm, and the single sludge discharge volume is 4% of the volume), and the Ca²⁺ deposit removal rate is 85%.

[0059] In addition, the embodiment of the present invention also provides a high - salinity wastewater treatment system, including a bioreactor, which is filled with functionalized microbial capsules with a volume ratio of 45%. The functionalized microbial capsules are, from the inside to the outside:

[0060] Halotolerant bacteria core: Comprising trehalose and a calcium - crosslinked sodium alginate matrix, with a cell density of 1.2×10 9 CFU / mL;

[0061] Antiscaling layer: Composed of the composite of polyaspartic acid and magnesium - aluminum hydrotalcite, with a thickness of 40 μm;

[0062] Conductive layer: A three - dimensional network formed by in - situ polymerization of aniline and loading carbon nanotubes, with a volume resistivity ≤ 10 Ω·cm;

[0063] Responsive shell: Composed of a copolymer of N - isopropylacrylamide, methacrylic acid, and hydroxyethyl acrylamide.

[0064] The treatment capacity of the bioreactor is 20 m³ / d. After running for 90 days, the cell activity is maintained at 94%, the energy consumption is 0.9 kWh / m³, and the sludge production is 0.1 kg / m³.

[0065] Preferably, the high - salinity wastewater treatment system in this embodiment further includes:

[0066] A pretreatment unit, which includes a vortex flocculator. The vortex flocculation device is internally provided with a metal filter screen with a pore size of 50 μm. The surface of the metal filter screen is coated with a polytetrafluoroethylene hydrophobic coating with a mass fraction of 0.2%, and the linear velocity of the vortex flocculator is controlled at 1.0 - 1.5 m / s;

[0067] A crystallization control unit, integrating a 28 - 40 kHz ultrasonic generator and a hydrocyclone separator, with a seed crystal recovery rate ≥ 90%. The underflow port of the hydrocyclone separator is connected to an automatic sludge discharge valve. When the sludge level sensor detects a height > 30 cm, sludge discharge is triggered, and the single - time sludge discharge volume is < 5% of the volume of the hydrocyclone separator.

[0068] Example 2: The high - salt wastewater treatment method of this example is basically the same as that of Example 1, and the differences are as follows:

[0069] I. Wastewater pretreatment: Pass the wastewater through a vortex flocculator, control the linear velocity at 1.3 m / s, synchronously add 55 mg / L of polyacrylamide (molecular weight 8 million), and the suspended solids polymerize into flocs; then intercept the suspended solids through a metal filter screen and adjust the pH to 7.5, and the suspended solid removal rate reaches 95%; when the online monitored Ca²⁺ concentration > 800 mg / L, automatically add 8 mg / L of polyaspartic acid (molecular weight 4000), and the Ca²⁺ complexation rate is 88%.

[0070] II. Preparation of functionalized microbial capsules. The preparation method of the functionalized microbial capsules includes the following steps:

[0071] (1) Preparation of the salt - tolerant bacteria core: Inoculate salt - tolerant bacteria into a culture medium containing 125 g / L of NaCl and 6 g / L of trehalose for cultivation. Mix the obtained bacterial liquid with 3 wt% of sodium alginate and then drop it into 1 wt% CaCl2 solution. The core microspheres are prepared by electrostatic molding, and are solidified for 2 h at 25 °C and then shaped. The final concentration of trehalose in the solidification stage is 3%. The cell density in the prepared core microspheres is 1.0×10 9 CFU / mL, the cell survival rate is 93%, and the diameter of the core microspheres is (200 ± 20) μm.

[0072] (2) Construction of the anti - scaling layer: Immerse the core into a mixed solution containing 2 wt% of polyaspartic acid and 0.5 wt% of magnesium - aluminum hydrotalcite. The layer spacing of the magnesium - aluminum hydrotalcite is 0.75 nm, and after treatment at 38 °C for 25 min, an anti - scaling layer with a thickness of 30 μm is formed to obtain anti - scaling microspheres. The Ca²⁺ interception rate of the anti - scaling microspheres is 91%, and the Na⁺ permeability is 87%.

[0073] (3)Conductive layer formation: 0.1 wt% carboxylated carbon nanotubes were added to an aniline phosphate buffer solution with a pH of 4.0. After immersing the above-mentioned anti-scaling microspheres, 0.4 wt% ammonium persulfate was added dropwise, and a composite conductive layer of polyaniline-carbon nanotubes with a volume resistivity of 10 Ω·cm was formed on the outer periphery of the anti-scaling microspheres by electrodeposition.

[0074] (4)Responsive shell coating: The above-mentioned capsule blanks were placed in a copolymer prepolymer solution and cured by ultraviolet light for 25 min to form a responsive shell with a thickness of 80 μm, and then functionalized microbial capsules were obtained; the responsive shell has a swelling degree of 150-200% when pH > 8.5, and the released nano-montmorillonite particles have a particle size of 50-80 nm.

[0075] Three monomers, N-isopropylacrylamide (NIPAM), methacrylic acid (MAA), and hydroxyethyl acrylamide (HEA), with a molar ratio of 80:8:4 were mixed with 0.4 wt% nano-montmorillonite, and after adding a photoinitiator, a copolymer prepolymer solution was prepared.

[0076] III. Phased operation of the bioreactor: The functionalized microbial capsules were added to the bioreactor, and the pretreated wastewater was introduced into the bioreactor and treated in stages:

[0077] Adaptation period: The salt-tolerant bacteria culture solution was gradually increased from an initial salinity of 15 g / L to 23 g / L at a gradient of 0.8 g / L per day under the condition of a dissolved oxygen of 2.0 mg / L; by monitoring the cell density and survival rate, it was ensured that the cell growth rate ≥ 0.15 h⁻¹. When the salinity reached 23 g / L and the turbidity fluctuation of the bacterial solution < 6% and the intracellular Na⁺ / K⁺ ratio ≤ 0.2, the adaptation period ended;

[0078] Enhancement period: On the basis of a salinity of 23 g / L, a DC electric field of 0.4 V / cm was applied in cooperation with a pulsed electric field of 0.8 V / cm. The frequency of the pulsed electric field was 0.8 Hz, and the duty cycle was 1:4. At the same time, the salinity was increased to 30 g / L at a rate of 0.8 g / L per day, the COD removal rate was increased to 83%, and the fouling amount was 1.0 g / m²·d.

[0079] Stable period: Under the condition of a salinity of 30 g / L, a maintenance cycle of backwashing - ultrasonic - seed addition was performed daily. Specifically: first, backwash at a flow rate of 10 cm / s for 20 seconds, then perform ultrasonic treatment for 8 minutes, and then add 80 mg / L vaterite seeds.

[0080] IV. Crystallization control stage: Through ultrasonic waves of 28 kHz with a power density of 0.4 W / cm³, cooperate with a hydrocyclone to dynamically remove Ca²⁺ deposits, and the seed circulation rate > 90%.

[0081] Example 3: The method for treating high-salt wastewater in this example is basically the same as that in Example 1, except that:

[0082] I. Wastewater pretreatment: Pass the wastewater through a vortex flocculator, control the linear velocity at 1.1 m / s, and synchronously add 45 mg / L of polyacrylamide (molecular weight 8 million), and the suspended solids polymerize into flocs; then intercept the suspended solids through a metal filter screen and adjust the pH to 8.0, and the removal rate of suspended solids reaches 95%; when the online monitored Ca²⁺ concentration > 800 mg / L, automatically add 8 mg / L of polyaspartic acid (molecular weight 4000), and the Ca²⁺ complexation rate is 90%.

[0083] II. Preparation of functionalized microbial capsules. The preparation method of the functionalized microbial capsules includes the following steps:

[0084] (1) Preparation of salt-tolerant bacteria core: Inoculate salt-tolerant bacteria into a medium containing 150 g / L NaCl and 8 g / L trehalose for cultivation, mix the obtained bacterial liquid with 5 wt% sodium alginate, and then drop it into 3 wt% CaCl2 solution, and prepare core microspheres by electrostatic forming, and solidify for 2 h at 30 °C and then shape, and the final concentration of trehalose in the solidification stage is 5%. The cell density in the prepared core microspheres is 1.1×10 9 CFU / mL, the cell survival rate is 93%, and the diameter of the core microspheres is (200±20) μm.

[0085] (2) Construction of anti-scaling layer: Immerse the core in a mixed solution containing 2 wt% polyaspartic acid and 0.5 wt% magnesium-aluminum hydrotalcite, the layer spacing of magnesium-aluminum hydrotalcite is 0.75 nm, and treat it at 38 °C for 25 min to form an anti-scaling layer with a thickness of 30 μm, and obtain anti-scaling microspheres. The Ca²⁺ interception rate of the anti-scaling microspheres is 91%, and the Na⁺ permeation rate is 87%.

[0086] (3) Formation of conductive layer: In an aniline phosphate buffer solution with pH 4.8, add 0.2 wt% carboxylated carbon nanotubes, immerse the above anti-scaling microspheres, and then drop 0.6 wt% ammonium persulfate, and form a composite conductive layer of polyaniline-carbon nanotubes with a volume resistivity of 9.5 Ω·cm on the outer periphery of the anti-scaling microspheres by electrodeposition.

[0087] (4) Coating with responsive shell: Place the above capsule blank in a copolymer prepolymer solution and cure it by ultraviolet light for 30 min, and then form a responsive shell with a thickness of 120 μm to obtain functionalized microbial capsules; the responsive shell has a swelling degree of 150~200% when pH > 8.5, and the released nano-montmorillonite particles have a particle size of 50~80 nm.

[0088] Three monomers N-isopropylacrylamide (NIPAM), methacrylic acid (MAA), and 2-hydroxyethyl acrylamide (HEA) with a molar ratio of 88:12:6 were mixed with 0.6 wt% of nanometer montmorillonite, and after adding a photoinitiator, a copolymer prepolymer solution was prepared.

[0089] III. The bioreactor operates in stages: The functionalized microbial capsules are added to the bioreactor, and the pretreated wastewater is introduced into the bioreactor and treated in stages:

[0090] Adaptation period: The salt-tolerant bacteria culture solution is gradually increased from an initial salinity of 20 g / L to 27 g / L at a gradient of 1.2 g / L per day under a dissolved oxygen condition of 2.5 mg / L; by monitoring the cell density and survival rate, it is ensured that the cell growth rate ≥ 0.15 h⁻¹. When the salinity reaches 27 g / L and the turbidity fluctuation of the bacterial solution < 8% and the intracellular Na⁺ / K⁺ ratio ≤ 0.4, the adaptation period ends;

[0091] Enhancement period: Based on a salinity of 27 g / L, a DC electric field of 0.6 V / cm is applied in cooperation with a pulsed electric field of 1.2 V / cm. The frequency of the pulsed electric field is 1.2 Hz, and the duty cycle is 1:6. At the same time, the salinity is increased to 35 g / L at a rate of 1.2 g / L per day, the COD removal rate is increased to 85%, and the scaling amount is 1.1 g / m²·d.

[0092] Stable period: Under a salinity condition of 35 g / L, a maintenance cycle of backwashing - ultrasonic - seed addition is performed daily. Specifically: First, backwash at a flow rate of 20 cm / s for 40 seconds, then perform ultrasonic treatment for 12 minutes, and then add 120 mg / L of vaterite seeds.

[0093] IV. In the crystallization control stage, 35 kHz ultrasonic waves with an energy density of 0.6 W / cm³ are used to dynamically remove Ca²⁺ deposits in cooperation with a hydrocyclone separator, and the seed circulation rate > 90%.

[0094] Comparative example 1: This comparative example uses a traditional treatment method (no biological capsule + no staged control), which specifically includes the following steps:

[0095] The ordinary activated sludge method is adopted, without capsule protection, the salinity increase gradient is 0.2 g / L / d (traditional method), without electric field cooperation, and only the pH is adjusted during pretreatment.

[0096] When the salinity reaches 20 g / L, the survival rate of the bacteria is 30%, the COD removal rate is 55%, the scaling amount is 4.0 g / m²·d, high-salt wastewater with a salinity > 25 g / L cannot be treated, and the energy consumption is 1.5 kWh / m³ (66.7% higher than that in Example 1).

[0097] Comparative Example 2: A single-layer core structure biocapsule was used in this comparative example. The capsule only contained salt-tolerant bacteria cores (sodium alginate matrix, without an anti-scaling layer, a conductive layer, and a responsive shell). The pretreatment and crystallization control were the same as in Example 1.

[0098] Performance defects: Ca²⁺ directly entered the core, and the pores of the capsule were blocked by CaCO3 within 2 weeks (blockage rate 60%). The bacteria died due to mass transfer obstruction, the survival rate dropped to 45%, the COD removal rate dropped sharply to 50%, and the scaling amount was 5.5 g / m²·d.

[0099] Comparative Example 3: A four-layer biocapsule structure was used in this comparative example, but the relevant parameters exceeded the limits: the sodium alginate concentration was 2 wt% (<3 wt%, insufficient mechanical strength), the interlayer spacing of hydrotalcite was 0.85 nm (>0.78 nm, the Ca²⁺ interception rate dropped to 70%), and there was no staged control (the salinity was directly increased to 35 g / L).

[0100] Performance defects: The breakage rate of the core microspheres was 30%, the anti-scaling layer failed, the scaling amount was 3.0 g / m²·d, the survival rate of the bacteria was 50% (90 days), and the COD removal rate was 70% (15% lower than that in Example 1).

[0101] Comparative Example 4: This comparative example was basically the same as Comparative Example 3, except that the bioreactor adopted staged control, and the strategy and relevant parameters of the staged control were consistent with those in Example 1.

[0102] The salinity adaptation speed was increased to 1.0 g / L / d, and the survival rate of the bacteria was increased to 60%. However, due to the capsule structure defect, the scaling amount still reached 2.5 g / m²·d, and the COD removal rate was 75%.

[0103] Comparative Example 5: There was no functionalized microbial capsule in this comparative example, but the relevant pretreatment and staged control steps and parameters in Example 1 were adopted.

[0104] Free salt-tolerant bacteria (without capsule embedding) were used in this comparative example, with pretreatment and staged salinity - electric field regulation. Other conditions were the same as in Example 1.

[0105] Since free bacteria were easily damaged by the high-salinity environment, the survival rate was only 45% (90 days), the COD removal rate was 65%, the scaling amount was 2.0 g / m²·d, and the energy consumption was 1.2 kWh / m³.

[0106] Table 1 is a comparison table of the relevant parameters of Examples 1-3 and Comparative Examples 1-5

[0107] Group Salinity treatment range (g / L) COD removal rate (%) Cell viability (90 days) Scaling amount (g / m²・d) Example 1 32 (stationary phase) 85 94% 1.0 Example 2 30 (stationary phase) 83 93% 1.0 Example 3 35 (stationary phase) 85 93% 1.1 Comparative Example 1 ≤20 55 30% 4.0 Comparative Example 2 ≤25 50 45% 5.5 Comparative Example 3 ≤30 70 50% 3.0 Comparative Example 4 ≤30 75 60% 2.5 Comparative Example 5 ≤30 65 45% 2.0

[0108] As can be seen from Table 1 above:

[0109] (1)In Examples 1 - 3, at a salinity of 30 - 35 g / L, the cell survival rate reached 93% - 94%, and the activity was maintained at ≥90% after 90 days of operation, significantly superior to Comparative Example 1 (<30%), Comparative Example 2 (45%), and Comparative Example 5 (45%). This is because of the trehalose protection mechanism (osmotic pressure regulation + activation of salt - tolerance genes) in the salt - tolerant bacteria core and the nano - montmorillonite release function of the responsive shell, which synergistically improve the survival rate of microorganisms in high - salt environments and break through the bottleneck that the efficiency drops sharply when the salinity > 20 g / L by traditional methods.

[0110] (2)The fouling amount in Examples 1 - 3 was only 1.0 - 1.1 g / m²·d, which was reduced by 72.5% - 75% compared with Comparative Example 1 (4.0 g / m²·d) and reduced by 80% - 81.8% compared with Comparative Example 2 (5.5 g / m²·d).

[0111] Key technical contribution: The magnesium - aluminum hydrotalcite in the anti - fouling layer (layer spacing of 0.75 - 0.78 nm) selectively intercepts Ca²⁺ (interception rate ≥90%), combined with the "ultrasound + seed addition" maintenance cycle during the stable period (fouling amount reduced by 60% - 65%), forming a dual anti - fouling system of "internal barrier + external removal" to solve the problem of fouling and blockage in high - hardness wastewater.

[0112] (3)The COD removal rate in Examples 1 - 3 reached 83% - 85%, significantly higher than that in Comparative Example 1 (55%), Comparative Example 2 (50%), and Comparative Example 5 (65%); and it operated stably in the long - term at a salinity of 30 - 35 g / L, while Comparative Example 1 could not treat wastewater with a salinity > 25 g / L.

[0113] In the embodiments of the present invention, a phased regulation strategy (rapid acclimation during the adaptation period + electric - field synergy during the intensification period + maintenance cycle during the stable period) is coupled with a conductive layer (polyaniline - carbon nanotube, volume resistivity ≤10 Ω·cm) to improve the electron transfer efficiency and keep the microbial metabolic activity stable in high - salt environments.

[0114] Through the deep coupling of the four - layer structure of the functionalized microbial capsule (salt - tolerance protection + anti - fouling + conductivity + responsiveness) and the phased salinity - electric - field synergy regulation strategy, supplemented by a pretreatment and crystallization control unit, the present invention is comprehensively superior to the control group of traditional methods in key indicators such as salt tolerance, anti - fouling ability, treatment efficiency, and energy consumption control, achieving efficient and stable treatment of high - salt (30 - 35 g / L) and high - hardness (Ca²⁺ > 500 mg / L) wastewater.

[0115] Any numerical values recited herein include all values from the lower value to the upper value incremented by one unit therebetween, provided that there is a separation of at least two units between any lower value and any higher value. For example, if a value of the number of components or a process variable (such as temperature, pressure, time, etc.) is recited as being from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, it is intended that values such as 15 to 85, 22 to 68, 43 to 51, 30 to 32, etc. are also expressly recited in this specification. For values less than 1, a unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1. These are merely examples of what is intended to be specifically recited, and it is to be understood that all possible combinations of numerical values recited between the lowest value and the highest value are expressly recited in this specification in a similar manner.

[0116] Unless otherwise stated, all ranges include the endpoints and all numbers therebetween. The term “about” or “approximate” used in connection with a range is applicable to both endpoints of that range. Thus, “about 20 to 30” is intended to cover “about 20 to about 30”, including at least the specified endpoints.

[0117] It should be understood that the above description is for illustrative purposes and not for purposes of limitation. Many embodiments and many applications other than the examples provided will be apparent to those skilled in the art upon reading the above description. Accordingly, the scope of the present teachings should not be determined with reference to the above description, but should be determined with reference to the appended claims and the full scope of equivalents to which such claims are entitled. For the sake of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein from the foregoing claims is not intended to abandon such subject matter, nor should the inventors be regarded as having excluded such subject matter from the disclosed inventive subject matter.

[0118] The above description with reference to the accompanying drawings has been made for purposes of illustration of the present invention. It is obvious that the specific implementation of the present invention is not limited by the above methods, as long as such non-substantial improvements are made by adopting the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, all are within the protection scope of the present invention.

Claims

1. A method for treating high-salt wastewater, characterized in that, The pretreated wastewater is introduced into a bioreactor filled with functionalized microbial capsules. The preparation method of the functionalized microbial capsules includes the following steps: (1) Preparation of the halotolerant bacteria core: The halotolerant bacteria are inoculated into a culture medium containing NaCl and trehalose for cultivation. The obtained bacterial solution is mixed with 3-5 wt% sodium alginate and then dropped into a 1-3 wt% CaCl2 solution. The core microspheres are prepared by electrostatic molding and solidified for a certain period of time at 20-30 °C and then shaped. (2) Construction of the anti-scaling layer: The core is immersed in a mixed solution containing 2-5 wt% polyaspartic acid and 0.5-1.5 wt% magnesium-aluminum hydrotalcite, and treated at a temperature of 38-45 °C for 25-35 min to form anti-scaling microspheres. (3) Formation of the conductive layer: In an aniline phosphate buffer solution with a pH of 4.0-4.8, 0.1-0.2 wt% carboxylated carbon nanotubes are added. After immersing the above anti-scaling microspheres, 0.4-0.6 wt% ammonium persulfate is added, and a composite conductive layer of polyaniline-carbon nanotubes is deposited on the outer periphery of the anti-scaling microspheres by electro-deposition. (4) Coating with the responsive shell: The above capsule blank is placed in the copolymer prepolymer solution and cured by ultraviolet light for a certain period of time. After forming a responsive shell with a thickness of 80-100 μm, the functionalized microbial capsules are obtained. Three monomers N-isopropylacrylamide, methacrylic acid, and hydroxyethyl acrylamide with a molar ratio of (80-88):(8-12):(4-6) are mixed with 0.4-0.6 wt% of nano-montmorillonite, and after adding a photoinitiator, a copolymer prepolymer solution is prepared.

2. The high-salt wastewater treatment method according to claim 1, characterized in that, The functionalized microbial capsules are added to the bioreactor, and the pretreated wastewater is introduced into the bioreactor and treated in stages: Adaptation period: The halotolerant bacteria culture solution is gradually increased from an initial salinity of 15-20 g / L to 23-27 g / L at a gradient of 0.8-1.2 g / L per day under the condition of a dissolved oxygen of 2.0-2.5 mg / L, and lasts for 4-7 days. By monitoring the cell density and survival rate, it is ensured that the growth rate ≥ 0.08-0.15 h⁻¹. When the salinity reaches 23-27 g / L and the turbidity fluctuation of the bacterial solution < 5-8% and the intracellular Na⁺ / K⁺ ratio ≤ 0.2-0.4, the adaptation period ends. Enhancement period: Based on a salinity of 23-27 g / L, a DC electric field of 0.4-0.6 V / cm is applied in cooperation with a pulsed electric field of 0.8-1.2 V / cm. The frequency of the pulsed electric field is 0.8-1.2 Hz, and the duty cycle is 1:4-1:

6. At the same time, the salinity is increased to 30-35 g / L at a rate of 0.8-1.2 g / L per day. Stable period: Under the condition of a salinity of 30-35 g / L, a maintenance cycle of backwashing-ultrasonic treatment-seed addition is performed daily. Specifically: first, backwash at a flow rate of 10-20 cm / s for 20-40 seconds, then perform ultrasonic treatment for 8-12 minutes, and then add 80-120 mg / L of vaterite seeds.

3. The high-salt wastewater treatment method according to claim 1, characterized in that, The trehalose is added at a concentration of 6-8 g / L during the bacterial cultivation stage and maintains a final concentration of 3-5% by mass fraction during the solidification stage. And / or, the NaCl is added at a concentration of 125-150 g / L during the bacterial cell culture stage.

4. The high-salt wastewater treatment method according to claim 1, characterized in that, The interlayer spacing of the magnesium-aluminum hydrotalcite in the anti-scaling layer is 0.75-0.78 nm, the Ca²⁺ interception rate is ≥90% and the Na⁺ transmittance is ≥85%.

5. The high-salt wastewater treatment method according to claim 1, characterized in that, The responsive outer shell has a swelling degree of 150-200% at pH>8.5 and synchronously releases nano-montmorillonite.

6. The high-salt wastewater treatment method according to any one of claims 1-5, characterized in that The wastewater pretreatment includes the following steps: Pass the wastewater through a vortex flocculator, control the linear velocity at 1.2±0.1 m / s, and synchronously add 45-55 mg / L of polyacrylamide, and the suspended substances polymerize into flocs; Then intercept the suspended substances through a metal filter screen and adjust the pH to 7.5-8.0; When the online monitored Ca²⁺ concentration>800 mg / L, automatically add 8-12 mg / L of polyaspartic acid.

7. The high-salt wastewater treatment method according to claim 1, characterized in that, It also includes a crystallization control stage. Through ultrasonic waves of 25-35 kHz and a power density of 0.4-0.6 W / cm³, a hydrocyclone is used to dynamically remove Ca²⁺ deposits, and the seed recycling rate>90%.

8. A system for implementing the high-salt wastewater treatment method according to any one of claims 1-7, characterized in that, It includes a bioreactor, and the bioreactor is filled with functionalized microbial capsules with a volume ratio of 40-50%. The functionalized microbial capsules are, from the inside to the outside: Halotolerant Bacteria Core: Comprising trehalose and a calcium-crosslinked sodium alginate matrix, wherein the cell density ≥ 10 9 CFU / mL; Anti-scaling layer: Composed of polyaspartic acid and magnesium-aluminum hydrotalcite, with a thickness of 30-50 μm; Conductive layer: A three-dimensional network formed by in-situ polymerization of aniline and loading carbon nanotubes, with a volume resistivity ≤10 Ω·cm; Responsive outer shell: Composed of a copolymer of N-isopropylacrylamide, methacrylic acid, and hydroxyethylacrylamide.

9. The high-salt wastewater treatment system according to claim 8, characterized in that, It also includes: A pretreatment unit, which includes a vortex flocculator. The vortex flocculation device is internally provided with a metal filter screen with a pore size of 45-55 μm, and the linear velocity of the vortex flocculator is controlled at 1.0-1.5 m / s; A crystallization control unit, which integrates a 28-40 kHz ultrasonic generator and a hydrocyclone, with a seed recovery rate ≥90%. The underflow port of the hydrocyclone is connected to an automatic sludge discharge valve. When the sludge level sensor detects a height>30 cm, sludge discharge is triggered, and the single sludge discharge volume is <5% of the volume of the hydrocyclone.

10. The high-salt wastewater treatment system according to claim 9, wherein The surface of the metal filter screen is coated with a polytetrafluoroethylene hydrophobic coating with a mass fraction of 0.1-0.3%.

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