Method for targeted adsorption and degradation of organic matter and antibacterial substance in recirculating aquaculture

Abstract

The application discloses a kind of circulating water aquaculture organic matter and antibiotic targeted adsorption degradation method, belong to aquaculture pond water treatment technical field, steps are as follows: the water outlet of mandarin fish culture pond is introduced into microfilter and retained solid phase pollutants;Water outlet enters raw water pool after buffer tank;Raw water pool water outlet enters biological filter and degrades organic matter;Water outlet flows into molecular imprinting targeted adsorption unit, and antibiotic, hormone are captured by double-targeted molecular imprinting polymer adsorbent;Water outlet enters heterogeneous electrofenton catalytic oxidation unit, and electrolysis is synergized with composite catalyst to catalyze and mineralize pollutant;After water outlet is neutralized pool, into air-lift culture tower reoxygenation and culture beneficial bacteria;After sensor monitoring, water quality reaches standard and then backflow aquaculture pond, otherwise backflow to targeted adsorption unit secondary treatment.The application effectively solves the problems that existing mandarin fish culture circulating water treatment process is difficult to target removal terramycin and other pollutants, which causes accumulation, low adsorption and oxidation efficiency, material easy to inactivate, lack of intelligent control, poor water quality adaptability of effluent.

Description

Technical Field

[0001] This invention relates to the field of aquaculture pond water treatment technology, and in particular to a method for targeted adsorption and degradation of organic matter and antibiotics in recirculating aquaculture systems. Background Technology

[0002] Factory-style high-density mandarin fish farming, due to its high stocking density and large feed input, easily accumulates large particulate solid pollutants such as uneaten feed and feces in the aquaculture water. This is accompanied by increases in biodegradable organic matter and ammonia nitrogen. Furthermore, the need for disease prevention during the farming process and the introduction of antibiotics such as oxytetracycline and hormones such as 17β-estradiol introduce persistent pollutants. Existing aquaculture recirculating water treatment processes primarily rely on physical filtration and biodegradation, which can only remove suspended solids, conventional organic matter, and ammonia nitrogen. They lack the ability to target and remove antibiotics and hormones, achieving only trace amounts of natural degradation, leading to the continuous accumulation of these pollutants in the water.

[0003] The long-term accumulation of pollutants not only disrupts the micro-ecological balance of aquatic bodies, inhibits the activity of beneficial bacteria in aquaculture water, and reduces the water's redox capacity, but also leads to intestinal flora imbalance and endocrine disturbance in mandarin fish, resulting in decreased disease resistance, slow growth, and reduced feed utilization. Furthermore, it can produce drug residues in the muscle of mandarin fish, posing a risk to the quality and safety of aquatic products. At the same time, if conventional adsorption and oxidation technologies are used in traditional treatment processes, problems such as adsorption sites being occupied by conventional organic matter, large dosage of oxidizing agents, and easy deactivation and loss of catalysts are likely to occur. These issues result in low treatment efficiency and high operating costs, making it difficult to meet the recirculating water reuse requirements of factory-scale mandarin fish farming and hindering the green and efficient development of high-density aquaculture. Summary of the Invention

[0004] The purpose of this invention is to provide a targeted adsorption and degradation method for organic matter and antibiotics in recirculating aquaculture systems, which solves the problems of existing recirculating aquaculture systems for mandarin fish farming that cannot target and remove recalcitrant pollutants such as oxytetracycline and 17β-estradiol, resulting in their accumulation and residue, poor adsorption targeting, low oxidation catalytic efficiency, easy deactivation and loss of materials, lack of intelligent control of each unit, unstable treatment effect, and difficulty in adapting the effluent quality to the needs of high-density aquaculture reuse.

[0005] To achieve the above objectives, the present invention provides a method for targeted adsorption and degradation of organic matter and antibiotics in recirculating aquaculture systems, comprising the following steps: Step S1, Primary pretreatment of aquaculture water: The effluent from the mandarin fish farming pond is introduced into a microfiltration machine to remove solid pollutants; Step S2: Homogenization and buffering of water quality and quantity: The water effluent from the microfiltration unit enters the buffer tank to eliminate fluctuations in water quality and quantity, and the water effluent from the buffer tank flows into the raw water tank. Step S3: Biodegradation to reduce burden: The effluent from the raw water tank enters the biological filter for the degradation of organic matter; Step S4: Targeted adsorption and enrichment of pollutants: The effluent from the biofilter flows upwards into the molecularly imprinted targeted adsorption unit, where a dual-target molecularly imprinted polymer adsorbent precisely captures antibiotics and hormones in the water through specific binding sites. The adsorption saturation of the dual-target molecularly imprinted polymer adsorbent is monitored in real time by an online concentration detector. When the saturation reaches a set value, the heterogeneous electro-Fenton catalytic oxidation unit is activated. When the saturation drops to the target value, the dual-target molecularly imprinted polymer adsorbent is chemically regenerated using a mixture of ethanol and acetic acid. Step S5: Heterogeneous electro-Fenton catalytic oxidation mineralization of contaminants: The effluent from the molecularly imprinted targeted adsorption unit enters the heterogeneous electro-Fenton catalytic oxidation unit, where pollutants are mineralized by electrolysis synergistically using Fe3O4@C composite catalyst to catalyze H2O2. Step S6: Catalyst online regeneration: The catalyst surface contaminants are desorbed by reverse electrochemical polarization by applying a reverse voltage, and ultrasonic cleaning is initiated simultaneously to synergistically remove residual adsorbates and regenerate the catalyst. Step S7: Aquaculture water adaptation and optimization treatment: The effluent from the heterogeneous electro-Fenton catalytic oxidation unit enters the neutralization tank, where it undergoes pH adjustment and degassing. The degassed effluent then enters the airlift culture tower, where it is aerated and reoxygenated, and beneficial bacteria are cultivated to regulate the bacterial balance of the water body. Step S8: Water quality monitoring and recirculation: The effluent from the airlift culture tower is monitored by an ORP sensor. If the water quality meets the standards, it is directly returned to the mandarin fish farming pond; otherwise, the effluent is returned to the molecularly imprinted targeted adsorption unit for secondary treatment.

[0006] Preferably, the mandarin fish farming pond, microfilter, buffer tank, raw water tank, biofilter, molecularly imprinted targeted adsorption unit, heterogeneous electro-Fenton catalytic oxidation unit, neutralization tank, and airlift culture tower are sequentially connected by a transfer pump and a transfer pipeline. The airlift culture tower and the mandarin fish farming pond are connected by a transfer pump and a transfer pipeline to form a water treatment cycle. Solenoid valves are installed on the transfer pipelines. A submersible pump is installed in the raw water tank to regulate the water supply flow and pressure. An ORP sensor for monitoring water quality is installed on the transfer pipeline connected to the outlet of the airlift culture tower.

[0007] Preferably, the molecularly imprinted targeted adsorption unit includes an adsorption column. From bottom to top, the adsorption column is sequentially arranged with a porous plate, water caps, a quartz sand pad, a dual-targeted molecularly imprinted polymer adsorbent, a lightweight porous layer, and water collection pipes. The porous plate is sealed to the inner surface of the adsorption column. The water caps are respectively sealed and embedded in the pores of the porous plate. The quartz sand pad fills the porous plate and extends above the top of the water caps. The dual-targeted molecularly imprinted polymer adsorbent fills the quartz sand pad. The lightweight porous layer is laid on top of the dual-targeted molecularly imprinted polymer adsorbent. Several water collection pipes are arranged evenly on the lightweight porous layer. A gap is provided between the bottom of the water collection pipe and the lightweight porous layer. Sealing blocks are provided between adjacent water collection pipes and between the water collection pipe and the inner surface of the adsorption column. A porous cap is sealed on the water inlet at the bottom of the water collection pipe.

[0008] Preferably, the porous plate is located above the bottom inlet of the adsorption column, and the water collection pipe is located below the top outlet of the adsorption column. The bottom inlet of the adsorption column is connected to the biological filter through a delivery pump and a delivery pipe. A backwash port is provided at the top of the adsorption column, and a backwash outlet is provided at the bottom of the adsorption column. Solenoid valves are provided at the bottom inlet, the top outlet, the backwash port, and the backwash outlet. The backwash port is connected to a storage tank containing a mixture of ethanol and acetic acid through a delivery pump and a delivery pipe.

[0009] Preferably, in step S4, the dual-target molecularly imprinted polymer adsorbent captures antibiotics and hormones in the water, namely oxytetracycline and 17β-estradiol. The chemical regeneration process is as follows: Close the solenoid valves at the bottom inlet and top outlet of the adsorption column, and open the solenoid valves at the backwash port and backwash outlet. The ethanol-acetic acid mixture in storage tank 1 is then transported into the adsorption column through the backwash port to regenerate the dual-target molecularly imprinted polymer adsorbent.

[0010] Preferably, the heterogeneous electro-Fenton catalytic oxidation unit includes an electrolysis reactor. Inside the electrolysis reactor are titanium-based iridium-tantalum coated electrodes arranged vertically and parallelly at equal intervals, with the cathodes and anodes paired. The upper and lower ends of each titanium-based iridium-tantalum coated electrode are fixed to the inner surface of the electrolysis reactor via insulating supports. The top of the titanium-based iridium-tantalum coated electrode extends above the water surface and is connected to a DC power supply located outside the electrolysis reactor via a connecting wire. The connecting wire and its connection to the titanium-based iridium-tantalum coated electrode are sealed with a sealing sleeve and waterproof insulating adhesive. A Fe3O4@C composite catalyst is suspended between the cathode and anode of the titanium-based iridium-tantalum coated electrode.

[0011] Preferably, the bottom of the electrolysis reactor is provided with a microporous aeration disc for the Fe3O4@C composite catalyst and a microporous aeration disc for providing O2 to H2O2. The microporous aeration disc is located below the titanium-based iridium-tantalum coated electrode and the Fe3O4@C composite catalyst. The microporous aeration disc is connected to a gas delivery device placed outside the electrolysis reactor through a gas delivery pipe. The upper and lower sides of the electrolysis reactor are respectively provided with a reactor inlet and a reactor outlet. The reactor inlet is connected to the outlet at the top of the adsorption column through a delivery pump and a delivery pipe. The reactor outlet is connected to the inlet of the neutralization tank through a delivery pump and a delivery pipe. Several ultrasonic transducers are evenly attached to the side of the electrolytic reactor, and the ultrasonic transducers are connected to the ultrasonic generator.

[0012] Preferably, the delivery pipe connected to the top outlet of the adsorption column is connected to the detection tank via bypass pipe one and delivery pump, and the detection tank is connected to the delivery pipe connected to the reactor inlet via bypass pipe two and delivery pump. The detection tank monitors the pollutant concentration in the adsorption column outlet in real time via online concentration detector two, providing data basis for precise H2O2 dosing. A mixer is installed on the conveying pipe connected to the reactor inlet. The mixer is connected to a storage tank containing H2O2 via a metering pump and a conveying pipe. A pH sensor and a dosing pipe are installed on the conveying pipe connected to the adsorption column outlet. The dosing pipe is connected to a storage tank containing dilute sulfuric acid and sodium hydroxide via a metering pump and a conveying pipe. The dilute sulfuric acid and sodium hydroxide in storage tank three are separated. Bypass pipe 1, pH sensor 1, and dosing pipe are arranged sequentially from near to far from the adsorption column on the conveying pipe connected to the adsorption column outlet. Bypass pipe 2 and mixer are arranged sequentially from far to near the electrolysis reactor on the conveying pipe connected to the reactor inlet. A water level sensor is installed on the upper inner surface of the electrolysis reactor. The water level sensor is located below the top of the titanium-based iridium-tantalum coated electrode and is used to monitor the water level inside the electrolysis reactor.

[0013] Preferably, a pH sensor 2 for detecting pH is installed in the neutralization tank. The neutralization tank is connected to a storage tank 4 containing dilute sulfuric acid and sodium hydroxide via a metering pump and a delivery pipeline. The dilute sulfuric acid and sodium hydroxide in the storage tank 4 are separated.

[0014] Preferably, the microfilter, transfer pump, metering pump, pH sensor 1, pH sensor 2, DC power supply, gas delivery equipment, online concentration detector 1, online concentration detector 2, water level sensor, solenoid valve, and controller are connected together.

[0015] The advantages and positive effects of the targeted adsorption and degradation method for organic matter and antibiotics in recirculating aquaculture systems described in this invention are as follows: 1. It has strong targeting and high removal efficiency, and can accurately capture and completely mineralize refractory pollutants such as oxytetracycline and 17β-estradiol in aquaculture water, improve the removal rate, solve the problems of pollutant accumulation in water and residual fish muscle, and ensure the quality and safety of aquatic products. 2. The dual-targeted MIPs adsorbent and Fe3O4@C composite catalyst maintain high adsorption and catalytic activity after regeneration, and the supporting measures effectively prevent material loss, significantly reducing the cost of repeated addition, and are suitable for long-term continuous industrial operation. 3. The synergistic effect of each process unit, the pretreatment stage effectively reduces the organic load, avoids non-target substances occupying adsorption sites, ensures the efficiency of subsequent targeted treatment, and the pH, COD and ammonia nitrogen of the treated water are all suitable for the high-density aquaculture of mandarin fish, and the ORP value meets the standard, which can realize the efficient recycling of aquaculture water and improve the utilization rate of water resources. 4. Through intelligent control, various process parameters can be monitored and precisely adjusted in real time, realizing the automation of adsorption saturation calculation, reagent addition, water quality compliance determination and secondary treatment of substandard water bodies, reducing manual intervention and ensuring stable and controllable treatment effect.

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall process of an embodiment of the targeted adsorption and degradation method for organic matter and antibiotics in recirculating aquaculture according to the present invention; Figure 2 This is a schematic diagram of a molecularly imprinted targeted adsorption unit in an embodiment of a method for targeted adsorption and degradation of organic matter and antibiotics in recirculating aquaculture according to the present invention. Figure 3 This is a bottom view of the water collection pipe arrangement in an embodiment of the targeted adsorption and degradation method for organic matter and antibiotics in recirculating aquaculture according to the present invention. Figure 4 This is a schematic diagram of a heterogeneous electro-Fenton catalytic oxidation unit, representing an embodiment of a method for targeted adsorption and degradation of organic matter and antibiotics in recirculating aquaculture according to the present invention.

[0018] Figure label: 1. Adsorption column; 2. Porous plate; 3. Water distribution cap; 4. Quartz sand pad; 5. Dual-target molecularly imprinted polymer adsorbent; 6. Lightweight porous laminate; 7. Water collection pipe; 8. Sealing block; 9. Porous cover; 10. Electrolytic reactor; 11. Titanium-based iridium-tantalum coated electrode; 12. Insulating support; 13. Fe3O4@C composite catalyst; 14. Microporous aeration disc; 15. Ultrasonic transducer; 16. Water level sensor; 17. Bypass pipe one; 18. pH sensor one; 19. Dosing pipe; 20. Bypass pipe two; 21. Mixer; 22. Backwash port; 23. Backwash outlet. Detailed Implementation

[0019] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit the scope of this application.

[0021] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0022] like Figure 1 As shown, the recirculating aquaculture system's targeted adsorption and degradation method for organic matter and antibiotics utilizes a mandarin fish farming pond, a microfilter, a buffer tank, a raw water tank, a biofilter, a molecularly imprinted targeted adsorption unit, a heterogeneous electro-Fenton catalytic oxidation unit, a neutralization tank, and an airlift culture tower to achieve recirculating water treatment. The various units are connected via pumps and pipelines. The airlift culture tower and the mandarin fish farming pond are also connected via pumps and pipelines to form a water treatment cycle. A PLC controller enables intelligent control of the overall water circulation process. Solenoid valves are installed on all pipelines. The recirculating aquaculture system's targeted adsorption and degradation method for organic matter and antibiotics includes the following steps: Step S1, Primary pretreatment of aquaculture water: The effluent from the mandarin fish farming pond is introduced into a microfiltration machine (drum microfiltration machine) to intercept solid pollutants such as uneaten feed, feces, and large particulate organic matter.

[0023] Step S2: Homogenization and buffering of water quality and quantity: The effluent from the microfiltration unit enters the buffer tank to eliminate fluctuations in water quality and quantity, ensuring stable operation of subsequent units. The submersible pump in the raw water tank adjusts the water supply flow and pressure according to the needs of subsequent units, while aeration (using existing aeration discs) maintains dissolved oxygen ≥5mg / L to prevent water deterioration.

[0024] Step S3: Biodegradation to reduce burden: The effluent from the raw water tank enters the biological filter (using a fluidized bed biological filter), where the microbial community on the surface of the filter media degrades biodegradable organic matter in the water and converts ammonia nitrogen into nitrate, achieving a removal of COD≥60% and ammonia nitrogen≥90%, reducing organic load and preventing subsequent adsorption unit sites from being occupied; the dissolved oxygen in the effluent from the biological filter is maintained above 5mg / L.

[0025] Step S4: Targeted adsorption and enrichment of pollutants: The effluent from the biological filter flows upward into the molecularly imprinted targeted adsorption unit, where dual-targeted molecularly imprinted polymer adsorbent 5 (dual-targeted MIPs adsorbent) precisely captures oxytetracycline and 17β-estradiol in the water through specific binding sites, controlling the hydraulic retention time to 1-2 hours.

[0026] The adsorption saturation of the dual-target molecularly imprinted polymer adsorbent 5 is monitored in real time by an online concentration detector. When the saturation reaches the set value (80%), the heterogeneous electro-Fenton catalytic oxidation unit is triggered. When the saturation drops to the target value (60%), the dual-target molecularly imprinted polymer adsorbent 5 is chemically regenerated using a mixture of ethanol and acetic acid (ethanol:acetic acid ratio of 9:1). After regeneration, the adsorption capacity is restored to over 95%.

[0027] like Figure 2 , Figure 3 As shown, the molecularly imprinted targeted adsorption unit includes an adsorption column 1. Inside the adsorption column 1, from bottom to top, are arranged a porous plate 2, a water distribution cap 3, a quartz sand pad 4, a dual-targeted molecularly imprinted polymer adsorbent 5, a lightweight porous layer 6, and a water collection pipe 7. The porous plate 2 is sealed to the inner surface of the adsorption column 1, and the water distribution caps 3 are respectively sealed and embedded in the pores of the porous plate 2. The quartz sand pad 4 fills the porous plate 2 and extends above the top of the water distribution caps 3. The dual-targeted molecularly imprinted polymer adsorbent 5 fills the quartz sand pad 4, and the lightweight porous layer 6 is laid on top of the dual-targeted molecularly imprinted polymer adsorbent 5. Several water collection pipes 7 are arranged evenly on the lightweight porous layer 6, with a gap between the bottom of the water collection pipe 7 and the lightweight porous layer 6. Sealing blocks 8 are provided between adjacent water collection pipes 7 and between the water collection pipe 7 and the inner surface of the adsorption column 1. A porous cap 9 is sealed on the water inlet at the bottom of the water collection pipe 7. The porous cover 9 is used to achieve uniform water flow and to prevent the outflow of the lightweight porous layer 6 (such as porous ceramic balls).

[0028] The porous plate 2 is located above the bottom inlet of the adsorption column 1, and the water collection pipe 7 is located below the top outlet of the adsorption column 1. The bottom inlet of the adsorption column 1 is connected to the biological filter via a transfer pump and a transfer pipe. A backwash port 22 is provided at the top of the adsorption column 1, and a backwash outlet 23 is provided at the bottom of the adsorption column 1. Solenoid valves are installed at the bottom inlet, the top outlet, the backwash port 22, and the backwash outlet 23 of the adsorption column 1. The backwash port 22 is connected to a storage tank containing a mixture of ethanol and acetic acid via a transfer pump and a transfer pipe.

[0029] The chemical regeneration process is as follows: Close the solenoid valves at the bottom inlet and top outlet of adsorption column 1, and open the solenoid valves at backwash port 22 and backwash outlet 23. The ethanol-acetic acid mixture from storage tank 1 is then introduced into adsorption column 1 through backwash port 22 to regenerate the dual-target molecularly imprinted polymer adsorbent 5. Ethanol is a good solvent that can disrupt the hydrophobic interaction between the adsorbent and oxytetracycline / 17β-estradiol; acetic acid is an acidic reagent that can dissociate the hydrogen bonds and ionic bonds between the adsorbent and pollutants. The synergistic effect of these two substances completely desorbs pollutants adsorbed at specific sites on the MIPs. Simultaneously, the mixture does not damage the polymer backbone and specific binding sites of the MIPs, thus the adsorption capacity after regeneration can be restored to over 95% of its initial value. During regeneration, the quartz sand pad 4 and the lightweight porous press 6 limit excessive loss and layer disorder of the dual-target molecularly imprinted polymer adsorbent 5, ensuring that the adsorbent 5 can quickly return to its original state after regeneration without the need for refilling. The adsorption column 1 is equipped with an activated carbon waste gas adsorption and collection tank to uniformly adsorb and treat the regenerated volatile organic waste gas, preventing fugitive emissions. The regenerated waste liquid flows into the concentrated waste liquid buffer tank through the backwash outlet 23 and pipeline for temporary storage and periodic treatment.

[0030] The dual-targeting MIPs adsorbent was prepared by precipitation polymerization using silica gel as the substrate. The imprinted molecules were oxytetracycline and 17β-estradiol, the functional monomer was MAA, and the crosslinking agent was EDMA. The molar ratio of imprinted molecules:MAA:EDMA was 1:4:20. The polymerization temperature was 60℃ and the reaction time was 8 hours. The specific preparation steps are as follows: Substrate pretreatment: The silica gel was placed in a 10% hydrochloric acid solution and refluxed at 80°C for 2 hours. It was then washed with deionized water until neutral and dried at 105°C to constant weight to obtain activated silica gel. Pre-assembled system: Oxytetracycline and 17β-estradiol were mixed in an equimolar ratio, anhydrous ethanol was added, and after stirring to dissolve, methacrylic acid (MAA) was added. The mixture was magnetically stirred at room temperature for 1 hour to allow the imprinted molecules and functional monomers to form a pre-assembled complex through hydrogen bonding and hydrophobic interactions. Preparation of polymerization system: Ethylene glycol dimethacrylate (EDMA) and activated silica gel were added to the pre-assembled composite. After stirring evenly, azobisisobutyronitrile (AIBN, added at 1% of the total mass of monomers) was added. The mixture was degassed by sonication for 20 min and the reaction system was sealed under nitrogen protection. Thermally initiated polymerization: The sealed reaction system was placed in a 60°C constant temperature water bath and magnetically stirred for 8 hours to obtain a crude product of molecularly imprinted polymer supported on silica gel. Imprinted molecule elution: The crude product was extracted with an ethanol-acetic acid mixture (volume ratio 9:1) using Soxhlet extraction for 24 h to completely elute the imprinted molecules, thus obtaining a dual-targeting MIPs adsorbent with specific binding sites. Post-treatment: The eluted adsorbent is washed with deionized water until neutral, vacuum dried at 60℃ for 12 hours, and then passed through an 80-100 mesh sieve to obtain the finished product (specific surface area ≥ 800 m²). 2 / g, adsorption capacity ≥50mg / g).

[0031] One online concentration detector is installed on each of the conveying pipes connected to the inlet and outlet of adsorption column 1. These detectors can simultaneously detect the concentrations of oxytetracycline and 17β-estradiol, and support real-time data transmission to the PLC controller via a 485 communication line. The online concentration detectors collect the pollutant concentrations in the influent and effluent in real time. The PLC controller automatically calculates and updates the actual adsorption capacity and adsorption saturation of the adsorbent based on the concentration difference. The calculation formula is as follows: Adsorption saturation = Actual cumulative adsorption capacity (mg) / Total initial adsorption capacity of adsorbent (mg) 100%; Actual cumulative adsorption capacity = Q t (C1-C2) K; Where Q represents the influent flow rate (m³) of adsorption column 1. 3 / h); t represents the adsorption time (h); C1 represents the pollutant concentration at the inlet of adsorption column 1 (mg / m³). 3 C2 represents the concentration of pollutants at the outlet of adsorption column 1 (mg / m³). 3 K represents the adsorption efficiency correction coefficient (taken as 0.95, to adapt to the actual mass transfer loss in engineering). Total initial adsorption capacity of adsorbent = Adsorbent loading mass (g) Initial adsorption capacity (≥50 mg / g).

[0032] Step S5: Heterogeneous electro-Fenton catalytic oxidation mineralization of contaminants: The effluent from the molecularly imprinted targeted adsorption unit enters the heterogeneous electro-Fenton catalytic oxidation unit. Before entering, the PLC controller automatically adds 5% dilute sulfuric acid or 5% sodium hydroxide via a metering pump, adjusting the pH to 3.5-4.5. After entering, the microporous aeration disc 14 is activated to maintain dissolved oxygen at 6-8 mg / L. Based on the pollutant concentration monitored by the online concentration detector, a 30% H2O2 solution is precisely added at a pollutant:H2O2 ratio of 1:100 (molar ratio). The DC power supply is turned on, and a voltage of 4-5V is applied to the cathode and anode of the titanium-based iridium-tantalum coated electrode 11 (titanium-based IrO2 electrode). The cathode electrolyzes to produce H2O2, and the suspended Fe3O4@C composite catalyst catalyzes the decomposition of H2O2 to generate ·OH. The hydraulic retention time is controlled at 1.5-2.5h. ·OH completely mineralizes the pollutants into CO2, H2O, and inorganic ions, with a pollutant degradation rate ≥98%. The ceramic nanofiltration membrane at the effluent end of the heterogeneous electro-Fenton catalytic oxidation unit retains the Fe3O4@C composite catalyst to prevent loss.

[0033] like Figure 4 As shown, the heterogeneous electro-Fenton catalytic oxidation unit includes an electrolytic reactor 10. Titanium-based iridium-tantalum coated electrodes 11 are disposed inside the electrolytic reactor 10. The titanium-based iridium-tantalum coated electrodes 11 are arranged vertically, parallel, and equidistantly in a cathode-anode pairing manner. The upper and lower ends of each titanium-based iridium-tantalum coated electrode 11 are fixed to the inner surface of the electrolytic reactor 10 by polytetrafluoroethylene (PTFE) insulating supports 12. The top of the titanium-based iridium-tantalum coated electrode 11 extends above the water surface and is connected to a DC power supply located outside the electrolytic reactor 10 via a connecting wire. The connecting wire and the connection point between the connecting wire and the titanium-based iridium-tantalum coated electrode 11 are sealed with a PTFE sealing sleeve and waterproof insulating adhesive. An Fe3O4@C composite catalyst 13 (without direct contact with the titanium-based iridium-tantalum coated electrode 11) is suspended between the cathode and anode of the titanium-based iridium-tantalum coated electrode 11.

[0034] A microporous aeration disc 14 is located at the bottom of the electrolysis reactor 10, serving the Fe3O4@C composite catalyst 13 and providing O2 for H2O2. The microporous aeration disc 14 is positioned below the titanium-based iridium-tantalum coated electrode 11 and the Fe3O4@C composite catalyst 13. The microporous aeration disc 14 is connected via a gas delivery pipe to a gas delivery device (such as a blower or air pump) located outside the electrolysis reactor 10. A reactor inlet and a reactor outlet are respectively located on the upper and lower sides of the electrolysis reactor 10. The reactor inlet is connected to the top outlet of the adsorption column 1 via a delivery pump and a delivery pipe, and the reactor outlet is connected to the inlet of the neutralization tank via a delivery pump and a delivery pipe. Several ultrasonic transducers 15 are evenly attached to the sides of the electrolysis reactor 10, and the ultrasonic transducers 15 are connected to an ultrasonic generator.

[0035] The delivery pipe connected to the top outlet of adsorption column 1 is connected to the detection tank via bypass pipe 17 and a delivery pump. The detection tank is connected to the delivery pipe connected to the reactor inlet via bypass pipe 20 and a delivery pump. The detection tank monitors the pollutant concentration in the effluent from adsorption column 1 in real time using an online concentration detector, providing data for precise H2O2 dosing.

[0036] A mixer 21 is installed on the conveying pipe connected to the reactor inlet. The mixer 21 is connected to a storage tank containing H2O2 via a metering pump and a conveying pipe. A pH sensor 18 and a dosing pipe 19 are installed on the conveying pipe connected to the adsorption column 1 outlet. The dosing pipe 19 is connected to a storage tank containing dilute sulfuric acid and sodium hydroxide via a metering pump and a conveying pipe. The dilute sulfuric acid and sodium hydroxide in the storage tank are stored separately. Bypass pipe 17, pH sensor 18, and dosing pipe 19 are arranged in order of distance from adsorption column 1 to the conveying pipe connected to the adsorption column 1 outlet. Bypass pipe 20 and mixer 21 are arranged in order of distance from the electrolytic reactor 10 to the conveying pipe connected to the reactor inlet. A water level sensor 16 is installed on the upper inner surface of the electrolysis reactor 10. The water level sensor 16 is located below the top of the titanium-based iridium-tantalum coated electrode 11. The water level sensor 16 is used to monitor the water level inside the electrolysis reactor 10 and maintain the internal water level. If the water level exceeds the water level sensor 16, the corresponding solenoid valve is closed to stop the water from entering the electrolysis reactor 10 and prevent the water from exceeding the top of the titanium-based iridium-tantalum coated electrode 11.

[0037] This unit is an electro-Fenton + heterogeneous catalytic coupling system. The titanium-based IrO2 electrode is the core for electrolytic H2O2 production, and Fe3O4@C is the heterogeneous Fenton catalyst. The two work synergistically to generate strong oxidizing hydroxyl radicals (·OH, oxidation potential 2.8V), which thoroughly mineralize pollutants in three steps: Electrolysis produces H2O2: At the cathode of titanium-based IrO2, under a DC voltage of 3-6V, the oxygen reduction reaction (ORR) occurs: O2 + 2H+ + +2e - →H2O2 (Aeration continuously provides O2 to ensure the generation of H2O2); Heterogeneous Fenton reaction: Fe in Fe3O4@C 2+ / Fe 3+ Redox reaction catalyzes the decomposition of H2O2 to generate ·OH:Fe 2+ +H₂O₂→Fe 3+ +·OH+OH - Fe 3+ +H₂O₂→Fe 2+ +·OOH+H + The C matrix enhances electron transfer efficiency and accelerates Fe. 3+ Reduced to Fe 2+ Fe2+ / Fe 3+ The circulation simultaneously inhibits the aggregation of Fe3O4 particles; Pollutant mineralization: ·OH non-selectively attacks the molecular bonds of oxytetracycline and 17β-estradiol, gradually degrading them into small molecule organic matter, and finally completely mineralizing them into CO2, H2O and inorganic ions, with a degradation rate of ≥98%.

[0038] The Fe3O4@C composite catalyst was prepared by hydrothermal synthesis, using FeCl3·6H2O as the iron source and glucose as the carbon source in a mass ratio of 1:2. The reaction temperature was 180℃, and the holding time was 12h. Hydrogen reduction was then carried out at 300℃ for 2h. Specific steps are as follows: ①Precursor preparation: FeCl3·6H2O and glucose were added to deionized water at a mass ratio of 1:2 and magnetically stirred for 30 minutes until completely dissolved to obtain a clear mixed solution; ② Hydrothermal reaction: The mixed solution was transferred to a high-pressure reactor lined with polytetrafluoroethylene, with a filling degree of 80%. After sealing, it was placed in a 180℃ forced-air drying oven for 12 hours and then naturally cooled to room temperature to obtain a black precipitate. ③ Separation and washing: The precipitate was washed three times by alternating centrifugation with deionized water and anhydrous ethanol (8000 r / min, 10 min) to remove unreacted raw materials and by-products. It was then vacuum dried at 60℃ for 6 h to obtain the Fe3O4 / C precursor. ④ Hydrogen reduction: The precursor was placed in a tube furnace, purged with nitrogen for 30 min to remove all air, and then hydrogen was introduced (flow rate 50 mL / min). The temperature was raised to 300℃ and held for 2 h. After natural cooling to room temperature, Fe3O4@C composite catalyst was obtained (Fe3O4 loading 30%-40%, particle size 50-100 nm, specific surface area 150 m²). 2 / g).

[0039] Step S6: Catalyst online regeneration: The Fe3O4@C composite catalyst is regenerated every 24-48 hours. The corresponding solenoid valve is closed, the inlet and outlet water of the electrolysis reactor 10 is stopped, the DC power supply is switched to a reverse voltage of 1.5-2V, and reverse electrochemical polarization is applied to desorb contaminants on the catalyst surface. At the same time, ultrasonic cleaning is started to remove residual adsorbates. The regeneration time is 30-60 minutes, and the regeneration rate is ≥90%. After regeneration, the Fe3O4@C composite catalyst is resuspended by aeration and stirring of the microporous aeration disc 14.

[0040] Step S7: Aquaculture water adaptation and optimization treatment: The effluent from the heterogeneous electro-Fenton catalytic oxidation unit enters the neutralization tank. The pH of the water is adjusted to 7.5-8.0 by automatically adding solution through a metering pump. Then, the aeration device (using the existing aeration disc) is turned on to deaerate for 10-15 minutes to remove residual H2O2 in the water, so that the residual H2O2 content is ≤0.1mg / L. After deaeration, the effluent enters the airlift culture tower (existing structure), where it is reoxygenated by aeration (dissolved oxygen ≥7mg / L) and beneficial bacteria are cultivated to regulate the microbial balance of the water.

[0041] The neutralization tank is equipped with a pH sensor 2 for detecting pH. The neutralization tank is connected to a storage tank 4 containing dilute sulfuric acid and sodium hydroxide via a metering pump and a delivery pipeline. The dilute sulfuric acid and sodium hydroxide in the storage tank 4 are separated.

[0042] Electrolysis reactor 10 pH adjustment: pH sensor 1 monitors the pH of the water in real time. When pH > 4.5, the PLC controller starts the metering pump to add 5% dilute sulfuric acid to lower the pH; when pH < 3.5, the PLC controller starts the metering pump to add 5% sodium hydroxide to raise the pH, so as to achieve automatic and precise control of pH 3.5-4.5.

[0043] pH adjustment in neutralization tank: After the electro-Fenton reaction, the effluent enters the neutralization tank. The pH sensor in the tank monitors the pH of the water, and the metering pump automatically adds 5% sodium hydroxide solution to adjust the pH of the water from 3.5-4.5 to 7.5-8.0, which is suitable for mandarin fish.

[0044] Step S8: Water quality monitoring and recirculation: An ORP sensor for monitoring water quality is installed on the delivery pipe connected to the outlet of the airlift culture tower. The water effluent from the front end of the airlift culture tower is monitored by the ORP sensor. If the ORP is ≥ 650mV, it means that the water quality meets the standard and is directly returned to the mandarin fish farming pond. If the ORP is < 650mV, the effluent is returned to the molecular imprinted targeted adsorption unit for secondary treatment.

[0045] The microfilter, transfer pump, metering pump, pH sensor 18, pH sensor 2, DC power supply, gas delivery equipment, online concentration detector 1, online concentration detector 2, water level sensor 16, solenoid valve, and other electrical control structures are connected to the PLC controller using existing electrical connections.

[0046] Example 1: laboratory 1. Experimental Objective The removal efficiency of the entire process pretreatment-targeted adsorption-heterogeneous electro-Fenton oxidation-water quality adaptation-intelligent closed-loop treatment system for oxytetracycline and 17β-estradiol in mandarin fish farming water was verified on a laboratory scale. The regeneration stability of the dual-targeted MIPs adsorbent and Fe3O4@C composite catalyst and the operational adaptability of the pilot system were also verified.

[0047] 2. Experimental Construction A 50L closed-loop recirculating aquaculture system for mandarin fish was constructed, comprising a complete treatment unit: a 50-100μm rotary drum microfilter (primary pretreatment) → a 5L small fluidized bed biofilter (ceramsite + volcanic rock filter media, particle size 3-5mm) → a 15L upflow adsorption column (9L silica-based dual-targeted MIPs adsorbent, 60% filling rate) → a 20L heterogeneous electro-Fenton electrolysis reactor → a 2L neutralization tank → a 3L airlift culture tower; the electro-Fenton reactor was equipped with: titanium-based IrO2 electrodes (anode-cathode spacing 2.5cm), Fe3O4@C composite catalyst (dosage 5g / L, suspended state, 500nm ceramic filter screen at the outlet), and 14 microporous aeration discs (…). Features include: silicone material (pore size 10-20μm); automatic addition of 5% sulfuric acid / 5% sodium hydroxide; online addition of 30% H2O2; intelligent monitoring and control: online HPLC monitor (online monitor 1 and online monitor 2 use the same HPLC online monitor, detection limit ≤0.001mg / L), pH sensor (pH sensor 1 and pH sensor 2 use the same pH sensor, ±0.02), ORP sensor (±5mV), and PLC controller (linking the adjustment of parameters of each unit); catalyst regeneration equipment: DC power supply with switchable positive and reverse voltages, and 120W / 40kHz ultrasonic cleaning assembly (transducer attached to the outer wall of the electro-Fenton reactor).

[0048] Simulated aquaculture water configuration: Tap water was used as the base water, with the addition of 0.08 mg / L oxytetracycline and 0.05 mg / L 17β-estradiol. At the same time, an appropriate amount of residual feed leachate and ammonia nitrogen were added to simulate the actual water quality of mandarin fish farming (COD≈80 ​​mg / L, ammonia nitrogen≈1.5 mg / L).

[0049] 3. Operating parameters Pretreatment / biodegradation: The rotary drum microfilter has a flow rate of 5L / h, the fluidized bed biofilter has a hydraulic retention time of 1h, and the dissolved oxygen is maintained above 5mg / L during aeration; Targeted adsorption: The hydraulic retention time of adsorption column 1 is 1.5h, the feed water is precisely pretreated with a 5μm filter membrane, the electro-Fenton unit is triggered when the adsorbent adsorption saturation reaches 80%, and the adsorption capacity is chemically regenerated with an ethanol-acetic acid mixture (9:1) when it drops to 60% of the initial value. Heterogeneous electric Fenton: PLC automatically adjusts pH to 4.0, H2O2 dosage is 8mg / L (pollutant to H2O2 molar ratio 1:100), DC power supply output voltage is 4.5V, microporous aeration disc 14 maintains dissolved oxygen at 7mg / L, and hydraulic retention time is 2h; Catalyst regeneration: regeneration cycle 48h, reverse electrochemical polarization voltage 1.8V, ultrasonic cleaning power 120W / 40kHz, synergistic regeneration time 45min; Water quality adaptation: Add 5% sodium hydroxide to the neutralization tank to adjust the pH to 7.8, and aerate for 12 minutes to remove residual H2O2; aerate and reoxygenate in the airlift culture tower to 7.5 mg / L dissolved oxygen, and cultivate beneficial Bacillus bacteria; Intelligent closed-loop: The pollutant concentration is monitored every 12 hours by an online HPLC monitor. The target ORP value is ≥650mV. If the target value is not met, the pollutant is returned to the adsorption unit for secondary treatment.

[0050] 4. Test Results Pretreatment / biodegradation stage: The rotary drum microfilter has a suspended solids removal rate of 88%, and the fluidized bed biofilter has a COD removal rate of 62% and an ammonia nitrogen removal rate of 91%, effectively reducing the treatment load of subsequent units; Adsorption unit: The adsorption rates for oxytetracycline and 17β-estradiol are 96.3% and 97.1%, respectively. After three chemical regenerations, the adsorption capacity still retains more than 96% of the initial value. Electro-Fenton unit: After degradation, the concentrations of oxytetracycline and 17β-estradiol in the aquaculture water decreased to 0.003 mg / L and 0.002 mg / L, respectively, with a total removal rate of 99.6% and a degradation rate of ≥98%. Catalyst stability: After five electrochemical and ultrasonic synergistic regenerations, the Fe3O4@C catalyst retained 93% of its activity, with no obvious agglomeration, and the catalyst loss rate through the filter screen was <0.5%. Water quality indicators: The treated effluent has a pH of 7.8, a residual H2O2 content of 0.08 mg / L, an ORP value of 680 mV, a COD reduced to 28 mg / L, and an ammonia nitrogen reduced to 0.12 mg / L, which meets the water quality requirements for mandarin fish farming.

[0051] Example 2: Factory production 1. Experimental Objective In a real-world factory-scale mandarin fish farming scenario, the long-term continuous operation stability, pollutant removal efficiency, aquaculture adaptability, and industrial application feasibility of the technical solution of the large-scale, end-to-end treatment system were verified.

[0052] 2. Application Scenarios and System Construction The test site is 1200m 2 Factory-style mandarin fish farming workshop, with a single pond volume of 50m³. 3 Mandarin fish farming density: 55 fish / m³ 3 Fish fry are 8-10cm in length; includes a complete processing unit: 3 x 50-100μm aquaculture-specific rotary drum microfiltration units → 80m 3Fluidized bed biological filter (ceramsite + volcanic rock composite filter media, 70% filling rate) → 300L upflow adsorption column 1 (180L silica-based dual-targeted MIPs adsorbent, 60% filling rate) → 500L heterogeneous electro-Fenton electrolysis reactor 10 → 10m 3 Neutralization pool→20m 3 Airlift culture tower; core configuration of the electro-Fenton reactor: titanium-based IrO2 electrodes (3cm anode-cathode spacing, 12 sets in total), Fe3O4@C composite catalyst (dosage 4g / L, suspended state, 500nm ceramic filter screen at the outlet), 14 microporous aeration discs (uniformly arranged throughout, air supplied by Roots blower), fully automatic dosing of 5% sulfuric acid / 5% sodium hydroxide, precise dosing of 30% H2O2 (multi-channel metering pump); regeneration and monitoring: DC power supply with switchable forward and reverse voltage, 150W / 40kHz ultrasonic cleaning (multi-transducer distributed arrangement), HPLC online monitoring instrument, multi-point pH / ORP / dissolved oxygen sensors, central PLC control cabinet (dynamically adjusts parameters of each unit); aquaculture pond accessories: oxygenation device, water quality monitoring probe, linked with the circulating water treatment system.

[0053] 3. Operating parameters Pretreatment / Biodegradation: Total flow rate of rotary drum microfilter 240m³ / h 3 / h, the hydraulic retention time of the fluidized bed biological filter is 0.8h, and the dissolved oxygen is maintained above 5.5mg / L during aeration; Targeted adsorption: The hydraulic residence time of adsorption column 1 is 1.2h, the water is filtered through a 5μm precision filter, the electro-Fenton unit is triggered when the adsorbent adsorption saturation reaches 80%, and chemical regeneration with an ethanol-acetic acid mixture (9:1) is performed every 15 days; Heterogeneous electro-Fenton: PLC automatically adjusts the influent pH to 3.8-4.2, dynamically adjusts the H2O2 dosage based on HPLC monitoring data (the molar ratio of pollutants to H2O2 is stable at 1:100), DC power supply output voltage is 4.2-4.8V, micropore aeration maintains dissolved oxygen at 6.5-7.5mg / L, and hydraulic retention time is 2h; Catalyst regeneration: regeneration cycle 48h, reverse electrochemical polarization voltage 1.5-2.0V, ultrasonic cleaning power 130-150W / 40kHz, synergistic regeneration time 60min, after regeneration aeration and stirring to resuspend the catalyst. Water quality adaptation: The neutralization tank adjusts the pH to 7.5-8.0 through automatic dosing, and aerates and deaerates for 15 minutes to ensure that the residual H2O2 is ≤0.1mg / L; the airlift culture tower has an air-to-water ratio of 15:1, reoxygenates to dissolved oxygen above 7mg / L, and cultivates a compound of beneficial bacteria, including photosynthetic bacteria and Bacillus. Intelligent closed-loop: The HPLC online monitor monitors the concentration of pollutants in aquaculture water / treated water every 12 hours. The target value of ORP is ≥650mV. If the effluent does not meet the standard, it is automatically returned to adsorption column 1 for secondary treatment. The PLC dynamically adjusts the adsorption residence time, electric Fenton voltage and H2O2 dosage.

[0054] 4. Test Results (Continuous operation for 180 days) Pretreatment results: The average suspended solids removal rate of the rotary drum microfilter is 86%, and the average COD removal rate of the fluidized bed biofilter is 60% and the ammonia nitrogen removal rate is 90%, effectively preventing organic pollutants from occupying adsorption sites; Pollutant removal: The concentrations of oxytetracycline and 17β-estradiol in the aquaculture water fluctuated between 0.03-0.1 mg / L, with a total removal rate consistently above 98.5%, and the pollutant concentration in the treated effluent was ≤0.007 mg / L; Adsorbent / catalyst stability: After 12 chemical regenerations, the dual-targeted MIPs adsorbent retains 95% of its initial adsorption capacity; the Fe3O4@C catalyst is regenerated every 48 hours, with a stable regeneration rate of 92%, and an activity retention rate of 88% after 6 months. The filter screen effectively prevents catalyst loss, with a total loss rate of <1%. Aquaculture water quality: The treated effluent has a stable pH of 7.5-8.0, H2O2 residue ≤0.09mg / L, COD ≤30mg / L, ammonia nitrogen ≤0.15mg / L, and ORP value of 650-720mV, which is fully compatible with the needs of mandarin fish farming. Results of mandarin fish farming: The residual value of oxytetracycline in the muscle of mandarin fish was 0.008 mg / kg, and there was no residual 17β-estradiol hormone; the survival rate of the farmed fish reached 97.5%, the average weight gain rate was 10.2% higher than that of conventional farming, and the feed conversion ratio was reduced to 1.25, which was significantly improved compared with the control group.

[0055] Supplement to Comparative Example 1 and Comparative Example 2: To visually verify the treatment advantages of this invention, two control groups (Comparative Example 1 and Comparative Example 2) with conventional circulating water treatment were set up under completely identical conditions as in Examples 1 and 2. Comparative Example 1 and Comparative Example 2 only used the circulating water treatment process commonly used in aquaculture, removing the molecularly imprinted targeted adsorption unit and the heterogeneous electro-Fenton catalytic oxidation unit. The other aquaculture conditions, system scale, and operating environment were completely identical, and the same indicators were monitored. The core experimental data of Examples 1 and 2 are compared with those of Comparative Examples 1 and 2 in Tables 1 and 2.

[0056] Table 1 Comparison of core experimental data between Example 1 and Comparative Example 1

[0057] Table 2 Comparison of core experimental data between Example 2 and Comparative Example 2

[0058] Experimental conclusions: This invention demonstrates significant and stable removal effects of oxytetracycline and 17β-estradiol in mandarin fish farming water, achieving a total removal rate of 99.6% in the laboratory and maintaining a stable rate of over 98.5% during long-term industrial operation. Conventional processes, on the other hand, can only remove trace amounts of these pollutants and lead to continuous accumulation of pollutants in the water. The dual-targeted MIPs adsorbent and Fe3O4@C composite catalyst exhibit excellent regeneration stability, maintaining high adsorption / catalytic activity even after multiple regenerations. Combined with retention measures, catalyst loss can be effectively controlled, making it suitable for long-term industrial production. The system meets the operational requirements of conventional processes; after treatment, the pH, COD, ammonia nitrogen, ORP and other indicators of the aquaculture water are all suitable for the high-density aquaculture requirements of mandarin fish, and the H2O2 residue meets the standards; the water quality indicators after conventional treatment are inferior to this system and cannot meet the requirements for recycling; it can solve the problem of antibiotic and hormone residues in the aquaculture water and mandarin fish muscle, with a survival rate of 97.5%, improved weight gain rate, reduced feed conversion ratio, and significantly optimized aquaculture benefits; mandarin fish cultured using conventional processes have the risk of excessive drug residues, and the survival rate and growth performance are significantly reduced.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for targeted adsorption and degradation of organic matter and antibiotics in recirculating aquaculture systems, characterized in that, Includes the following steps: Step S1, Primary pretreatment of aquaculture water: The effluent from the mandarin fish farming pond is introduced into a microfiltration machine to remove solid pollutants; Step S2: Homogenization and buffering of water quality and quantity: The water effluent from the microfiltration unit enters the buffer tank to eliminate fluctuations in water quality and quantity, and the water effluent from the buffer tank flows into the raw water tank. Step S3: Biodegradation to reduce burden: The effluent from the raw water tank enters the biological filter for the degradation of organic matter; Step S4: Targeted adsorption and enrichment of pollutants: The effluent from the biological filter flows upward into the molecularly imprinted targeted adsorption unit, where the dual-target molecularly imprinted polymer adsorbent (5) precisely captures antibiotics and hormones in the water through specific binding sites. The adsorption saturation of the dual-target molecularly imprinted polymer adsorbent (5) is monitored in real time by an online concentration detector. When the saturation reaches the set value, the heterogeneous electro-Fenton catalytic oxidation unit is triggered. When the saturation drops to the target value, the dual-target molecularly imprinted polymer adsorbent (5) is chemically regenerated using a mixture of ethanol and acetic acid. Step S5: Heterogeneous electro-Fenton catalytic oxidation mineralization of contaminants: The effluent from the molecularly imprinted targeted adsorption unit enters the heterogeneous electro-Fenton catalytic oxidation unit, where H2O2 is catalyzed by electrolysis in conjunction with the Fe3O4@C composite catalyst (13), mineralizing the pollutants. Step S6: Catalyst online regeneration: The catalyst surface contaminants are desorbed by reverse electrochemical polarization by applying a reverse voltage, and ultrasonic cleaning is initiated simultaneously to synergistically remove residual adsorbates and regenerate the catalyst. Step S7: Aquaculture water adaptation and optimization treatment: The effluent from the heterogeneous electro-Fenton catalytic oxidation unit enters the neutralization tank, where it undergoes pH adjustment and degassing. The degassed effluent then enters the airlift culture tower, where it is aerated and reoxygenated, and beneficial bacteria are cultivated to regulate the bacterial balance of the water body. Step S8: Water quality monitoring and recirculation: The effluent from the airlift culture tower is monitored by an ORP sensor. If the water quality meets the standards, it is directly returned to the mandarin fish farming pond; otherwise, the effluent is returned to the molecularly imprinted targeted adsorption unit for secondary treatment.

2. The method for targeted adsorption and degradation of organic matter and antibiotics in recirculating aquaculture systems according to claim 1, characterized in that: The mandarin fish farming pond, microfilter, buffer tank, raw water tank, biofilter, molecularly imprinted targeted adsorption unit, heterogeneous electro-Fenton catalytic oxidation unit, neutralization tank, and airlift culture tower are sequentially connected by a transfer pump and a transfer pipeline. The airlift culture tower and the mandarin fish farming pond are connected by a transfer pump and a transfer pipeline to form a water treatment cycle. Solenoid valves are installed on all the transfer pipelines. A submersible pump is installed in the raw water tank to regulate the water supply flow and pressure. An ORP sensor for monitoring water quality is installed on the transfer pipeline connected to the outlet of the airlift culture tower.

3. The method for targeted adsorption and degradation of organic matter and antibiotics in recirculating aquaculture systems according to claim 1, characterized in that: The molecularly imprinted targeted adsorption unit includes an adsorption column (1). Inside the adsorption column (1), from bottom to top, are arranged a porous plate (2), a water distribution cap (3), a quartz sand pad (4), a dual-targeted molecularly imprinted polymer adsorbent (5), a lightweight porous press layer (6), and a water collection pipe (7). The porous plate (2) is sealed to the inner surface of the adsorption column (1). The water distribution caps (3) are respectively sealed and embedded in the pores of the porous plate (2). The quartz sand pad layer (4) fills the porous plate (2) and extends above the top of the water distribution caps (3). The dual-targeted molecularly imprinted polymer adsorbent... Imprinted polymer adsorbent (5) is filled on the quartz sand pad (4), and a lightweight porous layer (6) is laid on the dual-targeted molecular imprinted polymer adsorbent (5). Several water collection pipes (7) are arranged evenly on the lightweight porous layer (6). A gap is provided between the bottom of the water collection pipe (7) and the lightweight porous layer (6). Sealing blocks (8) are provided between adjacent water collection pipes (7) and between the water collection pipe (7) and the inner surface of the adsorption column (1). A porous cover (9) is sealed on the water inlet at the bottom of the water collection pipe (7).

4. The method for targeted adsorption and degradation of organic matter and antibiotics in recirculating aquaculture systems according to claim 3, characterized in that: The porous plate (2) is located above the bottom inlet of the adsorption column (1), and the water collection pipe (7) is located below the top outlet of the adsorption column (1). The bottom inlet of the adsorption column (1) is connected to the biological filter through a delivery pump and a delivery pipe. A backwash port (22) is provided at the top of the adsorption column (1), and a backwash outlet (23) is provided at the bottom of the adsorption column (1). Solenoid valves are provided at the bottom inlet of the adsorption column (1), the top outlet of the adsorption column (1), the backwash port (22), and the backwash outlet (23). The backwash port (22) is connected to a storage tank containing a mixture of ethanol and acetic acid through a delivery pump and a delivery pipe.

5. The method for targeted adsorption and degradation of organic matter and antibiotics in recirculating aquaculture systems according to claim 4, characterized in that: In step S4, the dual-target molecularly imprinted polymer adsorbent (5) captures antibiotics and hormones in the water, namely oxytetracycline and 17β-estradiol. The chemical regeneration process is as follows: Close the solenoid valves at the bottom inlet and top outlet of the adsorption column (1), open the solenoid valves at the backwash port (22) and backwash outlet (23), and transport the ethanol-acetic acid mixture in the storage tank into the adsorption column (1) through the backwash port (22) to regenerate the dual-target molecularly imprinted polymer adsorbent (5).

6. The method for targeted adsorption and degradation of organic matter and antibiotics in recirculating aquaculture systems according to claim 4, characterized in that: The heterogeneous electro-Fenton catalytic oxidation unit includes an electrolysis reactor (10). Inside the electrolysis reactor (10) are titanium-based iridium-tantalum coated electrodes (11). The titanium-based iridium-tantalum coated electrodes (11) are arranged vertically in a cathode-anode pairing manner with equal spacing. The upper and lower ends of each titanium-based iridium-tantalum coated electrode (11) are fixed to the inner surface of the electrolysis reactor (10) by an insulating support (12). The top of the titanium-based iridium-tantalum coated electrode (11) extends out of the water surface and is connected to a DC power supply placed outside the electrolysis reactor (10) by a connecting line. The connecting line and the connection point between the connecting line and the titanium-based iridium-tantalum coated electrode (11) are sealed with a sealing sleeve and waterproof insulating glue. Fe3O4@C composite catalyst (13) is suspended between the cathode and anode of the titanium-based iridium-tantalum coated electrode (11).

7. The method for targeted adsorption and degradation of organic matter and antibiotics in recirculating aquaculture systems according to claim 6, characterized in that: The bottom of the electrolysis reactor (10) is provided with a Fe3O4@C composite catalyst (13) and a microporous aeration disc (14) for providing O2 to H2O2. The microporous aeration disc (14) is located below the titanium-based iridium-tantalum coated electrode (11) and the Fe3O4@C composite catalyst (13). The microporous aeration disc (14) is connected to a gas conveying device placed outside the electrolysis reactor (10) through a gas conveying pipe. The upper side and lower side of the electrolysis reactor (10) are respectively provided with a reactor inlet and a reactor outlet. The reactor inlet is connected to the top outlet of the adsorption column (1) through a conveying pump and a conveying pipe. The reactor outlet is connected to the inlet of the neutralization tank through a conveying pump and a conveying pipe. Several ultrasonic transducers (15) are evenly attached to the side of the electrolytic reactor (10), and the ultrasonic transducers (15) are connected to the ultrasonic generator.

8. The method for targeted adsorption and degradation of organic matter and antibiotics in recirculating aquaculture systems according to claim 7, characterized in that: The delivery pipe connected to the top outlet of the adsorption column (1) is connected to the detection tank through bypass pipe one (17) and delivery pump. The detection tank is connected to the delivery pipe connected to the reactor inlet through bypass pipe two (20) and delivery pump. The detection tank monitors the pollutant concentration of the water effluent from the adsorption column (1) in real time through online concentration detector two, providing data basis for the precise addition of H2O2. A mixer (21) is installed on the conveying pipe connected to the reactor inlet. The mixer (21) is connected to the storage tank containing H2O2 via a metering pump and a conveying pipe. A pH sensor (18) and a dosing pipe (19) are installed on the conveying pipe connected to the adsorption column (1). The dosing pipe (19) is connected to the storage tank containing dilute sulfuric acid and sodium hydroxide via a metering pump and a conveying pipe. The dilute sulfuric acid and sodium hydroxide in the storage tank are separated. Bypass pipe 1 (17), pH sensor 1 (18), and dosing pipe (19) are arranged from near to far from the adsorption column (1) on the conveying pipe connected to the outlet of the adsorption column (1). Bypass pipe 2 (20) and mixer (21) are arranged from far to near from the electrolysis reactor (10) on the conveying pipe connected to the inlet of the reactor. A water level sensor (16) is provided on the upper inner surface of the electrolysis reactor (10). The water level sensor (16) is located below the top of the titanium-based iridium-tantalum coated electrode (11). The water level sensor (16) is used to monitor the water level inside the electrolysis reactor (10).

9. The method for targeted adsorption and degradation of organic matter and antibiotics in recirculating aquaculture systems according to claim 8, characterized in that: The neutralization tank is equipped with a pH sensor 2 for detecting pH. The neutralization tank is connected to a storage tank 4 containing dilute sulfuric acid and sodium hydroxide via a metering pump and a delivery pipeline. The dilute sulfuric acid and sodium hydroxide in the storage tank 4 are separated.

10. The method for targeted adsorption and degradation of organic matter and antibiotics in recirculating aquaculture systems according to claim 1, characterized in that: Microfilter, delivery pump, metering pump, pH sensor 1 (18), pH sensor 2, DC power supply, gas delivery equipment, online concentration detector 1, online concentration detector 2, water level sensor (16), solenoid valve and controller connection.

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