A high-oil high-cod wastewater resource treatment system and method

Abstract

The application discloses a high-oil high-COD wastewater resource treatment system and method, and relates to the technical field of wastewater treatment. The system comprises a pretreatment module, a microbial population regulation module, a biochemical degradation module, a deep purification module and a resource recovery module. The application builds a full-process treatment system of pretreatment, microbial population regulation, biochemical degradation, deep purification and resource recovery, carries out multi-module collaborative optimization and process algorithm innovation, realizes efficient resource treatment of high-oil high-COD wastewater, guarantees the stability of subsequent treatment by pretreatment, improves the adaptability and degradation efficiency of high-salt high-oil wastewater by microbial population regulation, shortens the adaptation period, and enhances the anti-shock load capacity. Biochemical degradation realizes efficient collaborative removal of nitrogen, phosphorus and organic matter, deep purification ensures that the effluent meets the standard, resource recovery simultaneously realizes freshwater reuse and high-purity salt resource recovery, and forms a closed-loop system.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a system and method for the resource-based treatment of high-oil and high-COD wastewater. Background Technology

[0002] High-oil, high-COD wastewater widely originates from industries such as food processing, catering, slaughtering, petrochemicals, and coal chemicals. This type of wastewater contains large amounts of animal and vegetable oils, macromolecular organic matter, and suspended impurities, with COD concentrations typically reaching thousands to tens of thousands of mg / L and oil content accounting for 2%-5%. Direct discharge of this type of wastewater can lead to eutrophication of water bodies, damage to aquatic ecosystems, and blockage of treatment facilities due to oil adhering to pipes. Furthermore, the oils and organic matter within the wastewater are not recovered, resulting in significant waste. With increasingly stringent environmental standards and the promotion of resource recycling concepts, achieving efficient treatment and resource recovery of high-oil, high-COD wastewater has become a critical issue that the industry urgently needs to address, and it is of great significance for enterprises' environmental compliance and sustainable development.

[0003] Current technologies for treating high-oil and high-COD wastewater have many shortcomings. Chemical demulsification-coagulation processes require the addition of large amounts of acid, alkali, and flocculants. The high salt content generated by acid-alkali neutralization inhibits the efficiency of subsequent biological treatment and generates a large amount of oily sludge, causing secondary pollution and incurring high disposal costs. Single physical separation technologies can only remove free oils and cannot completely separate emulsified oils. Residual oils can easily lead to sludge expansion and treatment failure in subsequent reactors. Traditional biological treatment often uses single anaerobic or aerobic processes. Anaerobic processes are complex and unsuitable for the discontinuous wastewater discharge scenarios of small and medium-sized enterprises, while aerobic processes face problems such as incomplete COD degradation and high energy consumption. In addition, existing systems are mostly decentralized designs, with each treatment unit operating independently. The processes are lengthy, occupy a large area, and only focus on achieving emission standards, without realizing the effective recovery of resources such as oils and energy, resulting in low resource utilization.

[0004] Existing technologies suffer from low separation efficiency, high risk of secondary pollution, insufficient resource recovery, complex processes, and poor adaptability, making it difficult to simultaneously meet the dual requirements of environmental compliance and resource recycling. They also fail to satisfy the industry's urgent need for efficient, economical, and environmentally friendly treatment technologies. Therefore, developing a highly integrated treatment system and method that achieves efficient oil separation, deep COD degradation, and simultaneous resource recovery can effectively address the shortcomings of existing technologies, align with environmental policy requirements and enterprises' demands for cost reduction and efficiency improvement, and has significant practical application value and promising prospects for widespread adoption. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a resource-based treatment system and method for high-oil and high-COD wastewater. This system achieves efficient resource utilization of high-oil and high-COD wastewater by constructing a system with five synergistic modules: pretreatment, microbial regulation, biochemical degradation, deep purification, and resource recovery. The pretreatment module removes impurities and floating oil; the microbial regulation module adds salt-tolerant and oil-loving bacteria and compatible solutes to optimize the biochemical reaction environment; the biochemical degradation module combines anoxic-aerobic processes for nitrogen and phosphorus removal; the deep purification module ensures effluent quality through composite filtration and disinfection; and the resource recovery module integrates membrane separation and evaporation crystallization technologies to achieve freshwater reuse and salt resource recovery, forming a closed-loop treatment system that significantly improves wastewater treatment efficiency and resource utilization.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: On the one hand, a resource-based treatment system for high-oil and high-COD wastewater, the system comprising: a pretreatment module, a microbial community regulation module, a biochemical degradation module, a deep purification module, and a resource recovery module;

[0007] The pretreatment module is used to receive high-oil and high-COD wastewater, remove large particulate impurities and floating oil in the wastewater by mechanical bar interception and horizontal flow oil separation sedimentation tank, and transport the pretreated wastewater to the microbial control module.

[0008] The microbial community regulation module is connected to the pretreatment module and includes a salt-tolerant bacterial community addition device and a compatible solute addition device. It adopts a salt-tolerant bacterial community activity synergistic regulation algorithm to inoculate the received pretreatment wastewater with salt-tolerant oil-loving bacteria and regulate the osmotic pressure in the biochemical reaction tank. The resulting mixed system is then transported to the biochemical degradation module.

[0009] The formula for the algorithm for the coordinated regulation of salt-tolerant bacterial community activity is as follows: ,in, To regulate the actual activity of the alkali-tolerant oleophilic bacterial community; This represents the basic activity of halophilic and oleophilic bacterial communities; This is the salt inhibition coefficient; The actual salinity of the wastewater transported from the pretreatment module to the microbial community control module; The salinity tolerance threshold for salt-tolerant oleophilic bacteria; The compatibility coefficient of the solute; This refers to the actual amount of solute added to the biochemical reaction tank by the compatible solute addition device; This is the baseline dosage for compatible solutes; The uniformity coefficient of bacterial community mixing;

[0010] The biochemical degradation module is connected to the microbial community regulation module and includes an anoxic tank, an aerobic tank and a secondary sedimentation tank. It adopts a COD removal rate process coupling algorithm to remove nitrogen and phosphorus and degrade COD in the received mixed system. The supernatant formed by mud-water separation is transported to the deep purification module.

[0011] The formula for the COD removal rate process coupling algorithm is as follows: ,in, This represents the actual COD removal rate of the biochemical degradation module. This represents the basic COD removal rate. The actual activity of the microbial community output by the microbial community regulation module; This represents the basic activity of the bacterial community; The dissolved oxygen influence coefficient in the aerobic tank;

[0012] The deep purification module is connected to the biochemical degradation module and includes a composite filtration tank and a disinfection tank. It filters and disinfects the received supernatant, and the deep-purified effluent is transported to the resource recycling module.

[0013] The resource recovery module is connected to the deep purification module and includes a water quality testing device, a membrane separation device, and an evaporator crystallizer. It performs reuse treatment and salt resource recovery on the received deep purified effluent, and some of the recovered freshwater is returned to the pretreatment module.

[0014] Furthermore, the pretreatment module includes a mechanical bar screen and a horizontal flow oil-water separator sedimentation tank. The mechanical bar screen is a continuous rotary structure with a screen size of 5 to 8 mm and an operating frequency of 2 to 3 rotations per hour. The effective hydraulic retention time of the horizontal flow oil-water separator sedimentation tank is 2 to 3 hours, and the water flow velocity in the tank is 0.002 to 0.005 m / s.

[0015] Furthermore, the horizontal flow oil-water separator is equipped with a chain-type oil scraper at the top, with an operating speed of 0.5 to 1 m / min. A conical sludge discharge hopper is installed at the bottom of the tank, with a sludge discharge frequency of once every 8 to 12 hours and a single sludge discharge duration of 10 to 15 minutes.

[0016] Furthermore, the microbial community regulation module includes a salt-tolerant bacterial community addition device and a compatible solute addition device. The salt-tolerant oil-loving bacterial community in the salt-tolerant bacterial community addition device is composed of a mixture of Halomonas and Vibrio halophiles in a volume ratio of 1:1 to 2:1, and the bacterial community addition amount is 10 to 15% of the sludge concentration in the biochemical reaction tank. The solute in the compatible solute addition device is composed of a mixture of betaine and proline in a mass ratio of 1:1, and the solute addition concentration is 50 to 100 mg / L.

[0017] Furthermore, a submersible stirrer is installed in the biochemical reaction tank of the microbial community regulation module. The rotation speed of the submersible stirrer is 80 to 100 r / min, the microbial community acclimatization time is 3 to 5 days, and the microbial community morphology is continuously monitored during the acclimatization period.

[0018] Furthermore, the biochemical degradation module includes an anoxic tank, an aerobic tank, and a secondary sedimentation tank. In the anoxic tank, the submersible agitator rotates at 60 to 80 r / min, the dissolved oxygen concentration in the tank is less than 0.5 mg / L, and the hydraulic retention time is 8 to 12 h. In the aerobic tank, tubular microporous aerators are laid at the bottom, with an aerator pore size of 1 to 2 mm and an arrangement density of 2 to 3 aerators per square meter. The dissolved oxygen concentration in the tank is 2 to 3 mg / L, and the hydraulic retention time is 16 to 20 h.

[0019] Furthermore, the aerobic tank is equipped with a mixed liquor return pipeline connected to the anoxic tank, and the return ratio of the mixed liquor from the aerobic tank to the anoxic tank is 100% to 200%. The secondary sedimentation tank has a radial flow structure with an effective hydraulic retention time of 2 to 3 hours, and the return ratio of the sludge from the bottom of the tank to the anoxic tank is 50% to 100%.

[0020] Furthermore, the deep purification module includes a composite filtration tank and a disinfection tank. The lower layer of the composite filtration tank is laid with quartz sand filter media with a particle size of 0.8 to 1.2 mm and a thickness of 400 to 500 mm, and the upper layer is laid with activated carbon filter media with a particle size of 2 to 4 mm and a thickness of 300 to 400 mm. The filtration rate of the composite filtration tank is 5 to 8 m / h. The disinfection tank uses ultraviolet disinfection or sodium hypochlorite disinfection. The resource recovery module includes a membrane separation device and a vacuum evaporation crystallizer. The membrane separation device is a nanofiltration membrane module or a reverse osmosis membrane module. The operating temperature of the vacuum evaporation crystallizer is 60 to 70°C.

[0021] On the other hand, a method for the resource recovery treatment of high-oil and high-COD wastewater is characterized by the following specific steps:

[0022] S100, Pretreatment: Receives high-oil and high-COD wastewater, intercepts large particulate impurities through mechanical screens, and removes floating oil in a horizontal flow oil-water separation sedimentation tank;

[0023] S200, Microbial Community Regulation: Salt-tolerant and oil-loving bacteria and compatible solutes are added to the pretreated wastewater, and microbial community inoculation and osmotic pressure regulation are carried out in the biochemical reaction tank;

[0024] S300, Biochemical Degradation: The regulated mixed system is sequentially fed into the anoxic tank and the aerobic tank for nitrogen and phosphorus removal and COD degradation, and then separated into mud and water in the secondary sedimentation tank.

[0025] S400, Deep Purification: The supernatant from the secondary sedimentation tank undergoes composite filtration and disinfection.

[0026] S500 Resource Recovery: After deep purification, the effluent undergoes water quality testing, membrane separation, and evaporation crystallization to recover freshwater and salt resources. Some of the recovered freshwater is recycled back to the pretreatment step.

[0027] Compared with existing technologies, this resource-based treatment system and method for high-oil and high-COD wastewater has the following advantages:

[0028] I. This system achieves efficient resource recovery of high-oil and high-COD wastewater by constructing a complete treatment process encompassing pretreatment, microbial community regulation, biochemical degradation, deep purification, and resource recovery. The pretreatment module uses a combination of mechanical bar screens and horizontal flow oil-water separators to effectively intercept large particulate impurities and floating oil, ensuring the stability of subsequent treatment. The microbial community regulation module innovatively adds salt-tolerant and oil-loving bacteria and compatible solutes, and optimizes the microbial community structure through an active synergistic regulation algorithm, significantly improving the adaptability and degradation efficiency of high-salt and high-oil wastewater. The biochemical degradation module combines anoxic-aerobic processes to precisely control dissolved oxygen and hydraulic retention time, achieving nitrogen and phosphorus removal and deep COD removal. The deep purification module uses composite filtration and disinfection technologies to ensure that the effluent meets standards. The resource recovery module integrates membrane separation and evaporation crystallization technologies to simultaneously achieve freshwater reuse and salt resource recovery, forming a closed-loop treatment system that significantly reduces treatment costs and environmental risks.

[0029] II. This system overcomes the problems of poor bacterial adaptability, low degradation efficiency, and difficult resource recovery in traditional high-oil and high-COD wastewater treatment technologies through multi-module collaborative optimization and process algorithm innovation. The synergistic addition strategy of salt-tolerant and oil-loving bacteria and compatible solutes in the bacterial community regulation module, combined with real-time monitoring and acclimatization technology, significantly shortens the bacterial community adaptation cycle and improves the system's resistance to shock loads. The biochemical degradation module dynamically optimizes the operating parameters of the anoxic-aerobic unit through process coupling algorithms, achieving efficient synergistic removal of nitrogen, phosphorus, and organic matter. The deep purification module adopts a double-layer filter media composite filtration design, balancing interception capacity and filtration accuracy, and extending the service life of the filter media. The resource recovery module precisely controls crystallization conditions through the linkage of water quality detection and membrane separation technology, improving the purity and recovery rate of salt resources. This system integrates multiple advantages such as improved treatment efficiency, resource recycling, and reduced operating costs.

[0030] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from an examination of the following, or may be learned from the practice of the invention. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0032] Figure 1 A connection framework diagram of a resource recovery system for high-oil and high-COD wastewater;

[0033] Figure 2 A flowchart of a method for resource recovery treatment of high-oil and high-COD wastewater;

[0034] Figure 3 This is a schematic diagram of the microbial community regulation module structure of a resource recovery system for high-oil and high-COD wastewater. Detailed Implementation

[0035] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0036] Example 1

[0037] like Figure 1As shown, the enterprise's production wastewater is collected in a collection well and then pumped to a continuous rotary mechanical bar screen in the pretreatment module. This mechanical bar screen has a 5mm mesh size and operates at twice per hour. The continuous rotation of the screen precisely captures and traps large particles such as meat chunks, fascia, and hair in the wastewater, preventing blockages in subsequent treatment unit pipes and valves due to impurity accumulation, while also reducing equipment wear and extending its service life. The trapped large particles are transferred to an impurity collection tank and periodically transported off-site for harmless treatment to prevent secondary pollution. The wastewater, after the removal of large particles, enters a horizontal flow oil-water separator sedimentation tank. The effective hydraulic retention time in this sedimentation tank is controlled at 2 hours, and the water flow velocity is adjusted to 0.002m / s. This gentle water flow provides sufficient conditions for the natural floating of oil and the gravity settling of sludge, ensuring stable separation results. A chain-type oil skimmer installed at the top of the sedimentation tank operates continuously at a speed of 0.5 m / min, quickly scraping animal fat floating on the surface into the oil collection tank. The collected oil can be recycled as industrial oil raw material after subsequent refining, improving resource utilization. A conical sludge discharge hopper at the bottom of the tank operates every 8 hours, with each discharge lasting 10 minutes, promptly removing sludge and heavy oily sludge deposited at the bottom of the tank. This prevents sediment buildup from affecting the effective volume and separation efficiency of the tank. The discharged sludge is concentrated in a sludge thickening tank and then subjected to anaerobic digestion. The resulting biogas is used for boiler combustion and heating, realizing the resource utilization of sludge. After pretreatment, the oil content of the wastewater is reduced to below 50 mg / L, and the removal rate of large particulate impurities reaches over 95%. The water quality is initially purified, reducing the load on subsequent treatment units. The treated water is then transported to the microbial control module via pipeline.

[0038] The pretreated wastewater enters the biochemical reaction tank of the microbial community regulation module. This tank contains a pre-cultured concentration of activated sludge. To enhance the sludge's adaptability to high-salt, high-oil wastewater and its pollutant degradation efficiency, halophilic oleophilic bacteria are added to the reaction tank via a halophilic bacteria dosing device. This bacterial community consists of a 1:1 volume ratio of *Haloxylon ammodendron* and *Vibrio halophilus*, and the addition amount is controlled at 10% of the sludge concentration in the biochemical reaction tank, ensuring rapid colonization and the formation of a dominant community. Simultaneously, a compatible solute, a 1:1 mass ratio of betaine and proline, is added to the reaction tank via a compatible solute dosing device at a concentration of 50 mg / L. This solute regulates the wastewater's osmotic pressure, protects the bacterial cell membrane structure from damage caused by the high-salt environment, and maintains the bacterial community's metabolic activity and oil degradation capacity. The submersible agitator installed in the biochemical reaction tank operates continuously at a speed of 80 r / min, ensuring thorough mixing and contact between the salt-tolerant oil-loving bacteria, compatible solutes, and wastewater. This guarantees uniform distribution of the bacteria within the reaction tank and comprehensive contact with pollutants, thereby improving reaction efficiency. A synergistic regulation algorithm for the activity of salt-tolerant bacteria is employed, with the following formula: ,in, To regulate the actual activity of the alkali-tolerant oleophilic bacterial community; This represents the basic activity of halophilic and oleophilic bacterial communities; This is the salt inhibition coefficient; The actual salinity of the wastewater transported from the pretreatment module to the microbial community control module; The salinity tolerance threshold for salt-tolerant oleophilic bacteria; The compatibility coefficient of the solute; This refers to the actual amount of solute added to the biochemical reaction tank by the compatible solute addition device; This is the baseline dosage for compatible solutes; The coefficient for uniformity of microbial community mixing was used. By monitoring parameters such as wastewater salinity, oil concentration, and dissolved oxygen in real time, the dosage of microorganisms and the concentration of compatible solutes were dynamically adjusted to optimize the inoculation and acclimatization process and shorten the adaptation period. The acclimatization time was set at 3 days. During the acclimatization period, the morphology of the microorganisms was continuously monitored under a microscope. It was observed that the microbial cells were intact, reproduced actively, and formed a stable microbial community structure, which could efficiently decompose oil and organic matter in wastewater. After microbial regulation, the salinity adaptability of the wastewater was significantly improved, and the degradation activity of the microorganisms on oil was enhanced. The mixed system was then transported to the biochemical degradation module.

[0039] After microbial community regulation, the mixed system first enters the anoxic tank of the biochemical degradation module. The submersible agitator in this tank operates at a speed of 60 r / min to keep the mixed liquor in suspension, avoiding sludge settling and affecting the reaction effect. The dissolved oxygen concentration in the tank is strictly controlled below 0.5 mg / L, and the hydraulic retention time is 8 h. The anoxic environment provides suitable living conditions for denitrifying bacteria. The denitrifying bacteria can use the organic carbon source in the wastewater as an electron donor to reduce nitrate nitrogen in the mixed liquor returned from the aerobic tank to nitrogen gas, achieving efficient denitrification. The mixed liquor treated in the anoxic tank enters the aerobic tank. Tubular microporous aerators with 1mm pore size are evenly laid at the bottom of the aerobic tank, with a density of 2 aerators per square meter. Compressed air is introduced into the tank through the aeration system. Uniform aeration ensures that the dissolved oxygen concentration in the tank is maintained at 2 mg / L, and the hydraulic retention time is controlled at 16 hours. Sufficient oxygen supply meets the aerobic respiration requirements of aerobic microorganisms, enabling them to rapidly decompose organic matter in the wastewater, achieving efficient COD degradation. Simultaneously, nitrifying bacteria convert ammonia nitrogen in the wastewater into nitrate nitrogen, and polyphosphate-accumulating bacteria excessively absorb phosphorus from the wastewater, achieving simultaneous nitrogen and phosphorus removal. A process coupling algorithm for COD removal rate is adopted, with the formula: ,in, This represents the actual COD removal rate of the biochemical degradation module. This represents the basic COD removal rate. The actual activity of the microbial community output by the microbial community regulation module; This represents the basic activity of the bacterial community; The dissolved oxygen influence coefficient in the aerobic tank is calculated. By optimizing parameters such as hydraulic retention time and dissolved oxygen concentration in the anoxic and aerobic tanks, synergistic efficiency in nitrogen and phosphorus removal and COD degradation is achieved, improving the overall treatment effect. To enhance nitrogen removal, a mixed liquor return pipeline is installed in the aerobic tank to connect to the anoxic tank, with the mixed liquor return ratio controlled at 100%. The mixed liquor containing nitrate nitrogen in the aerobic tank is returned to the anoxic tank, providing sufficient substrate for the denitrification reaction and ensuring thorough nitrogen removal. The mixed liquor treated in the aerobic tank enters a radial flow secondary sedimentation tank. The effective hydraulic retention time in this sedimentation tank is 2 hours. The reasonable tank structure and retention time ensure efficient sludge-water separation under gravity. The supernatant is the intermediate product of the treated wastewater that meets the standards. The sludge settled at the bottom of the tank is returned to the anoxic tank at a 50% return ratio to maintain a stable sludge concentration in both the anoxic and aerobic tanks, ensuring the continuous and efficient biochemical reaction. The remaining sludge is discharged to the sludge treatment system. After biochemical degradation, the COD removal rate in the wastewater reaches over 90%, the ammonia nitrogen removal rate reaches over 85%, and the total phosphorus removal rate reaches over 95%, resulting in a significant improvement in water quality. The supernatant is then transported to the deep purification module.

[0040] The supernatant from the secondary sedimentation tank enters the composite filtration tank of the deep purification module. This filtration tank adopts a double-layer filter media structure. The lower layer is laid with quartz sand filter media with a particle size of 0.8mm and a thickness of 400mm. The uniform quartz sand filter media particles can effectively intercept fine suspended solids, colloidal particles, and other impurities in the water. The upper layer is laid with activated carbon filter media with a particle size of 2mm and a thickness of 300mm. The activated carbon filter media has a rich porous structure and can remove residual trace amounts of oil, color, odor, and some recalcitrant organic matter in the water through adsorption. The double-layer filter media work synergistically to enhance the filtration depth. The filtration rate of the filtration tank is controlled at 5m / h to ensure sufficient contact between the filter media and the wastewater while also considering treatment efficiency. The composite filtration tank is backwashed regularly to prevent filter media clogging and ensure stable operation of the filtration system. The filtered wastewater enters the disinfection tank and is disinfected using ultraviolet light. The ultraviolet light emitted by the ultraviolet lamps irradiates the wastewater, which can destroy the DNA structure of pathogenic microorganisms in the water, rendering them unable to reproduce and achieving the purpose of thorough sterilization and disinfection. After deep purification, the pollutant indicators of the wastewater are significantly reduced, with COD concentration dropping below 50 mg / L, oil content below 5 mg / L, and suspended solids content below 10 mg / L. The water quality meets the resource recovery standards and is then transported to the resource recovery module.

[0041] After deep purification, the effluent first enters the water quality testing device in the resource recovery module. This device monitors the effluent's COD, salinity, pH value, suspended solids, and other indicators in real time to accurately determine whether the effluent meets the requirements for membrane separation treatment, preventing substandard water quality from contaminating or damaging the membrane module. Once confirmed to meet the standards, it is sent to a nanofiltration membrane module for membrane separation treatment. The nanofiltration membrane module effectively removes residual salts, trace organic matter, and other impurities from the water. The water that permeates through the membrane is high-quality freshwater, while the retained liquid is rich in salt resources. A portion of the high-quality freshwater is returned to the pretreatment module for rinsing the mechanical bar screen, replenishing the horizontal flow oil-water separator, and cleaning equipment in various treatment units, reducing fresh water consumption and lowering water resource usage. The other portion is stored in a freshwater storage tank for use in floor washing, equipment cleaning, and primary rinsing after slaughter, achieving wastewater resource reuse. The retentate from the nanofiltration membrane module enters a vacuum evaporator crystallizer. This crystallizer operates at a controlled temperature of 60°C, allowing for rapid evaporation and concentration of water under vacuum, causing the salt in the retentate to crystallize and precipitate, yielding high-purity salt crystals. The recovered salt resources, after drying and purification, are reused as auxiliary salt in the company's meat curing process, achieving the recycling of salt resources. Figure 2 As shown.

[0042] Example 2

[0043] Wastewater from the enterprise's production processes is collected through the workshop's sewage pipes and flows into a wastewater equalization tank. The equalization tank is equipped with a stirring device to ensure uniform wastewater quality and quantity, preventing fluctuations in water quality from affecting the treatment effect in subsequent treatment units. The wastewater is then pumped to a continuous rotary mechanical bar screen in the pretreatment module. This mechanical bar screen has a mesh size of 8mm and operates at a frequency of 3 rotations per hour. It effectively traps large particles of impurities in the wastewater, such as oil refining residues, packing particles, and metal shavings from equipment wear, preventing blockages and wear on pipes, valves, and equipment in subsequent treatment units and ensuring stable system operation. The trapped large particles are collected and disposed of by a professional organization to prevent secondary pollution. The wastewater, after the removal of large particles, enters a horizontal flow oil-water separator sedimentation tank. The effective hydraulic retention time in this sedimentation tank is controlled at 3 hours, and the water flow velocity is adjusted to 0.005m / s. This slow flow velocity ensures sufficient retention of the wastewater in the tank, creating favorable conditions for oil separation and sedimentation of heavy pollutants, thus improving separation efficiency. A chain-type oil skimmer installed at the top of the sedimentation tank operates at a speed of 1 m / min, continuously skimming off floating vegetable oil and grease contaminants, quickly collecting a large amount of floating oil. The collected grease is further separated and purified by an oil-water separator, and can then be recycled as industrial raw material, improving resource recovery rates. The conical sludge discharge hopper at the bottom of the tank operates every 12 hours, with each discharge lasting 15 minutes, thoroughly removing heavy oily sludge, sludge, and other sediments deposited at the bottom of the tank, preventing sediment accumulation from occupying effective tank space and affecting sedimentation efficiency. The discharged sludge, after sludge thickening and dewatering, is sent to an incinerator for incineration. The heat generated from incineration is used for plant heating, achieving sludge reduction and resource recovery. The pretreated wastewater has an oil content reduced to below 80 mg / L, and a large particulate impurity removal rate of over 98%, effectively improving water quality and laying the foundation for subsequent biological treatment. The treated water is then transported via pipeline to the microbial community control module.

[0044] The pretreated wastewater enters the biochemical reaction tank of the microbial community regulation module. To adapt to the harsh environment of high salt and high oil content in the wastewater and improve the efficiency of biochemical treatment, halophilic oleophilic bacteria are added to the reaction tank through a halophilic bacteria addition device. This bacterial community consists of a 2:1 volume ratio of *Haloxylon ammodendron* and *Vibrio halophilus*, and the addition amount is controlled at 15% of the sludge concentration in the biochemical reaction tank. The relatively high addition amount ensures that the bacterial community can quickly form a dominant community in the reaction tank, shortening the adaptation period. At the same time, a compatible solute, a 1:1 mass ratio of betaine and proline, is added to the reaction tank through a compatible solute addition device at a concentration of 100 mg / L. The high concentration of compatible solute can effectively regulate the osmotic pressure of the wastewater, protect the cell membranes of the halophilic oleophilic bacteria from damage by the high salt environment, maintain the metabolic activity and degradation capacity of the bacterial community, and ensure that it can still efficiently degrade pollutants in a high-salt environment of 6%-8%. The submersible mixer installed in the biochemical reaction tank operates continuously at a speed of 100 rpm. This high speed ensures thorough mixing of the salt-tolerant, oil-loving bacteria, compatible solutes, and wastewater, guaranteeing uniform distribution of the bacteria within the tank and maximizing contact with pollutants, thereby increasing the reaction rate. A synergistic regulation algorithm for salt-tolerant bacterial activity is employed. Based on real-time monitoring data of wastewater salinity, oil concentration, and pH, the dosage of bacteria and the concentration of compatible solutes are dynamically adjusted to optimize inoculation and acclimatization conditions, enhancing bacterial adaptability. The acclimatization period is set at 5 days, allowing the bacteria to fully adapt to the wastewater characteristics. During acclimatization, morphological changes in the bacteria are regularly observed using a microbial microscope. The results show that the bacteria exhibit good cell growth, rapid reproduction, and the formation of a stable and functionally synergistic microbial community capable of efficiently degrading oils and organic matter in the wastewater. After acclimatization, the mixed system is transported to the biochemical degradation module.

[0045] After microbial community regulation, the mixed system first enters the anoxic tank of the biochemical degradation module. The submersible agitator in this tank operates at a speed of 80 r / min to keep the mixed liquid in suspension and prevent sludge settling. The dissolved oxygen concentration in the tank is strictly controlled below 0.5 mg / L, and the hydraulic retention time is 12 h. The sufficient retention time allows denitrifying bacteria to make full use of the organic pollutants in the wastewater as electron donors to reduce nitrate nitrogen in the mixed liquid returned from the aerobic tank to nitrogen gas, thus achieving deep denitrification. The mixed liquor treated in the anoxic tank enters the aerobic tank. Tubular microporous aerators with 2mm pore size are evenly laid at the bottom of the aerobic tank, with a density of 3 aerators per square meter. This dense aerator arrangement ensures uniform diffusion of compressed air, maintaining a dissolved oxygen concentration of 3 mg / L. The hydraulic retention time is controlled at 20 hours. This longer retention time and ample oxygen supply allow aerobic microorganisms to fully metabolize and efficiently decompose the large amount of organic matter in the wastewater, achieving deep COD degradation. Simultaneously, nitrifying bacteria convert ammonia nitrogen in the wastewater into nitrate nitrogen, while polyphosphate-accumulating bacteria absorb excess phosphorus from the wastewater and store it within their cells, achieving efficient phosphorus removal through sludge discharge. A COD removal rate process coupling algorithm is employed, optimizing the operating parameters of the anoxic and aerobic tanks to achieve synergistic efficiency in nitrogen and phosphorus removal and COD degradation, improving the overall treatment effect. To enhance denitrification efficiency, a mixed liquor return pipeline is installed in the aerobic tank, connecting it to the anoxic tank. The mixed liquor return ratio is controlled at 200%, providing ample nitrate substrate to the anoxic tank and ensuring stable and thorough denitrification. The mixed liquor treated in the aerobic tank enters a radial flow secondary sedimentation tank. This sedimentation tank has an effective hydraulic retention time of 3 hours. The optimized tank structure and retention time ensure efficient sludge-water separation under gravity. The supernatant is the intermediate effluent after biological treatment. The sludge settled at the bottom of the tank is returned to the anoxic tank at a 100% return ratio, maintaining stable sludge concentrations in both the aerobic and anoxic tanks and ensuring continuous and efficient biological reactions. Excess sludge is discharged to the sludge treatment system. After biological degradation, the COD removal rate in the wastewater reaches over 92%, the ammonia nitrogen removal rate over 90%, and the total phosphorus removal rate over 98%, meeting the requirements for deep purification. The supernatant is then transported to the deep purification module.

[0046] The supernatant from the secondary sedimentation tank enters the composite filtration tank of the deep purification module. This filtration tank adopts a double-layer filter media design. The lower layer is laid with quartz sand filter media with a particle size of 1.2mm and a thickness of 500mm. The larger particle size and thickness enhance the interception capacity of fine suspended solids, colloidal particles, and microbial flocs. The upper layer is laid with activated carbon filter media with a particle size of 4mm and a thickness of 400mm. The thick activated carbon layer can fully adsorb residual trace oils, color, odors, and recalcitrant organic matter in the water, further improving the water purity. The filtration rate of the filtration tank is controlled at 8m / h, which ensures filtration effect while improving treatment efficiency to meet the company's daily treatment needs of 5000 cubic meters. The composite filtration tank is backwashed regularly. The backwash water uses part of the freshwater generated by the resource recovery module. The backwash wastewater is returned to the pretreatment module for reprocessing to avoid water waste. The filtered wastewater enters a disinfection tank where sodium hypochlorite is used for disinfection. An appropriate amount of sodium hypochlorite solution is added to the tank via a sodium hypochlorite dosing device. The hypochlorous acid produced by the decomposition of sodium hypochlorite has strong oxidizing properties, effectively killing bacteria, viruses, and other pathogenic microorganisms in the water. After deep purification, the wastewater's COD concentration is reduced to below 30 mg / L, oil content to below 3 mg / L, and suspended solids content to below 5 mg / L. All indicators meet the requirements for subsequent resource recovery, and the wastewater is then transported to the resource recovery module.

[0047] The purified effluent first enters the water quality testing device in the resource recovery module. This device comprehensively tests the effluent's COD, salinity, pH value, conductivity, and other indicators to accurately control water quality. Once the effluent meets the membrane separation treatment standards, it is sent to the reverse osmosis membrane module for further treatment. The reverse osmosis membrane module has highly efficient retention capabilities, effectively removing impurities such as salt, trace organic matter, and heavy metal ions from the water. The water that permeates through the membrane is high-quality freshwater, while the retentate is rich in high-concentration salt resources. Part of the high-quality freshwater is returned to the pretreatment module for mechanical bar flushing, makeup water for the horizontal flow oil-water separator, and equipment cleaning and backwashing in various treatment units, reducing fresh water consumption. The other part is stored in a high-quality freshwater storage tank as makeup water for the company's production processes, used in the batching, cooling, and washing processes of fatty acid and fatty alcohol production, replacing traditional fresh water and reducing production costs and water consumption. The retentate produced by the reverse osmosis membrane module enters a vacuum evaporator crystallizer. This crystallizer operates at a controlled temperature of 70°C. This higher temperature accelerates water evaporation, rapidly concentrating and crystallizing the salts in the retentate to form high-purity salt crystals. The recovered salt resources, after dissolving, purifying, and drying, are recycled for use in the production of salt-containing catalysts, achieving a closed-loop cycle of salt resources and reducing raw material procurement and waste emissions. Figure 3 As shown.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any indirect modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A resource-based treatment system for high-oil and high-COD wastewater, characterized in that, The system includes: a pretreatment module, a microbial community regulation module, a biochemical degradation module, a deep purification module, and a resource recovery module; The pretreatment module is used to receive high-oil and high-COD wastewater, remove large particulate impurities and floating oil in the wastewater by mechanical bar interception and horizontal flow oil separation sedimentation tank, and transport the pretreated wastewater to the microbial control module. The microbial community regulation module is connected to the pretreatment module and includes a salt-tolerant bacterial community addition device and a compatible solute addition device. It adopts a salt-tolerant bacterial community activity synergistic regulation algorithm to inoculate the received pretreatment wastewater with salt-tolerant oil-loving bacteria and regulate the osmotic pressure in the biochemical reaction tank. The resulting mixed system is then transported to the biochemical degradation module. The biochemical degradation module is connected to the microbial community regulation module and includes an anoxic tank, an aerobic tank and a secondary sedimentation tank. It adopts a COD removal rate process coupling algorithm to remove nitrogen and phosphorus and degrade COD in the received mixed system. The supernatant formed by mud-water separation is transported to the deep purification module. The deep purification module is connected to the biochemical degradation module and includes a composite filtration tank and a disinfection tank. It filters and disinfects the received supernatant, and the deep-purified effluent is transported to the resource recycling module. The resource recovery module is connected to the deep purification module and includes a water quality testing device, a membrane separation device, and an evaporator crystallizer. It performs reuse treatment and salt resource recovery on the received deep purified effluent, and some of the recovered freshwater is returned to the pretreatment module.

2. The resource utilization system for high-oil and high-COD wastewater according to claim 1, characterized in that, The pretreatment module includes a mechanical bar screen and a horizontal flow oil-water separator sedimentation tank. The mechanical bar screen is a continuous rotary structure with a screen size of 5 to 8 mm and an operating frequency of 2 to 3 rotations per hour. The effective hydraulic retention time of the horizontal flow oil-water separator sedimentation tank is 2 to 3 hours, and the water flow velocity in the tank is 0.002 to 0.005 m / s.

3. The resource utilization system for high-oil and high-COD wastewater according to claim 1, characterized in that, The horizontal flow oil-water separator is equipped with a chain-type oil scraper at the top, with an operating speed of 0.5 to 1 m / min. A conical sludge discharge hopper is installed at the bottom of the tank, with a sludge discharge frequency of once every 8 to 12 hours and a single sludge discharge duration of 10 to 15 minutes.

4. The resource utilization system for high-oil and high-COD wastewater according to claim 1, characterized in that, The microbial community regulation module includes a salt-tolerant bacterial community addition device and a compatible solute addition device. The salt-tolerant oil-loving bacterial community in the salt-tolerant bacterial community addition device is composed of a mixture of Halomonas and Vibrio halophiles in a volume ratio of 1:1 to 2:1, and the bacterial community addition amount is 10 to 15% of the sludge concentration in the biochemical reaction tank. The solute in the compatible solute addition device is composed of a mixture of betaine and proline in a mass ratio of 1:1, and the solute addition concentration is 50 to 100 mg / L.

5. The resource utilization system for high-oil and high-COD wastewater according to claim 1, characterized in that, The biochemical reaction tank of the microbial community regulation module is equipped with a submersible stirrer with a rotation speed of 80 to 100 r / min and a microbial community acclimatization time of 3 to 5 days.

6. The resource utilization system for high-oil and high-COD wastewater according to claim 1, characterized in that, The biochemical degradation module includes an anoxic tank, an aerobic tank, and a secondary sedimentation tank. In the anoxic tank, the submersible agitator rotates at 60 to 80 r / min, the dissolved oxygen concentration in the tank is less than 0.5 mg / L, and the hydraulic retention time is 8 to 12 h. In the aerobic tank, tubular microporous aerators are laid at the bottom, with an aerator pore size of 1 to 2 mm and an arrangement density of 2 to 3 aerators per square meter. The dissolved oxygen concentration in the tank is 2 to 3 mg / L, and the hydraulic retention time is 16 to 20 h.

7. The resource utilization system for high-oil and high-COD wastewater according to claim 1, characterized in that, The aerobic tank is equipped with a mixed liquor return pipeline connected to the anoxic tank. The return ratio of the mixed liquor from the aerobic tank to the anoxic tank is 100% to 200%. The secondary sedimentation tank has a radial flow structure with an effective hydraulic retention time of 2 to 3 hours. The return ratio of the sludge from the bottom of the tank to the anoxic tank is 50% to 100%.

8. A resource recovery system for high-oil and high-COD wastewater according to claim 1, characterized in that, The deep purification module includes a composite filtration tank and a disinfection tank. The lower layer of the composite filtration tank is laid with quartz sand filter media with a particle size of 0.8 to 1.2 mm and a thickness of 400 to 500 mm. The upper layer is laid with activated carbon filter media with a particle size of 2 to 4 mm and a thickness of 300 to 400 mm. The filtration rate of the composite filtration tank is 5 to 8 m / h. The disinfection tank uses ultraviolet disinfection or sodium hypochlorite disinfection. The resource recovery module includes a membrane separation device and a vacuum evaporation crystallizer. The membrane separation device is a nanofiltration membrane module or a reverse osmosis membrane module. The operating temperature of the vacuum evaporation crystallizer is 60 to 70°C.

9. A method for resource recovery treatment of high-oil and high-COD wastewater, applicable to the high-oil and high-COD wastewater resource recovery treatment system described in any one of claims 1-8, characterized in that, The specific steps of this method are as follows: S100, Pretreatment: Receives high-oil and high-COD wastewater, intercepts large particulate impurities through mechanical screens, and removes floating oil in a horizontal flow oil-water separation sedimentation tank; S200, Microbial Community Regulation: Salt-tolerant and oil-loving bacteria and compatible solutes are added to the pretreated wastewater, and microbial community inoculation and osmotic pressure regulation are carried out in the biochemical reaction tank; S300, Biochemical Degradation: The regulated mixed system is sequentially fed into the anoxic tank and the aerobic tank for nitrogen and phosphorus removal and COD degradation, and then separated into mud and water in the secondary sedimentation tank. S400, Deep Purification: The supernatant from the secondary sedimentation tank undergoes composite filtration and disinfection. S500 Resource Recovery: After deep purification, the effluent undergoes water quality testing, membrane separation, and evaporation crystallization to recover freshwater and salt resources. Some of the recovered freshwater is recycled back to the pretreatment step.

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