Integrated catalytic biofilm composite and wastewater denitrification treatment method

Abstract

The application relates to the technical field of wastewater treatment, in particular to an integrated catalytic biofilm composite and a wastewater denitrification treatment method, which are prepared by the following method: a photocatalytic carrier is immersed in a heterotrophic nitrification and aerobic denitrification bacteria liquid, adsorption is carried out at 25 DEG C to 30 DEG C for 6 hours to 12 hours, and a bacteria-carrier composite is obtained; then the bacteria-carrier composite is immersed in a crosslinking liquid containing sodium alginate and calcium chloride to carry out crosslinking, and a gel-embedded integrated catalytic biofilm composite is formed; the volume ratio of the bacteria-carrier composite to the crosslinking liquid is 1:5-10; under the driving of visible light, photo-generated electrons are efficiently transferred to the bacteria electron transfer chain, the denitrification enzyme activity is significantly enhanced, and the material surface defect sites selectively degrade antibiotics. The application realizes efficient simultaneous denitrification and antibiotic removal under low-carbon source conditions, has strong system stability and low energy consumption, and is suitable for aquaculture, industrial and urban wastewater treatment.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to an integrated catalytic biofilm composite and a wastewater denitrification treatment method. Background Technology

[0002] Aquaculture wastewater, industrial wastewater, and municipal sewage contain high concentrations of ammonia nitrogen (NH4). + -N), nitrate nitrogen (NO3) - Nitrogen pollutants such as nitrogen oxides (NOx) and nitrogenous pollutants (N-N) can easily lead to serious environmental problems such as eutrophication, ecosystem damage, and drinking water source pollution if discharged directly without effective treatment. Traditional biological nitrogen removal processes mainly rely on the synergistic effect of nitrifying and denitrifying bacteria, but they have inherent drawbacks such as long process flow, large footprint, strict requirements for dissolved oxygen (DO) and carbon sources, slow system start-up, and weak resistance to shock loads. In recent years, heterotrophic nitrifying aerobic denitrifying bacteria (HNAD) have gradually become a research hotspot in the field of biological nitrogen removal because they can simultaneously carry out nitrification and denitrification reactions under aerobic conditions, achieving efficient nitrogen removal by a single strain and a single reactor. Existing studies have confirmed that Rhodococcus rubrum (Rhodococcus rubrum) Rhodococcus erythropolis HNAD strains, such as those mentioned above, have shown good denitrification potential when treating complex wastewaters such as aquaculture wastewater. However, in practical applications, HNAD bacteria lack environmental adaptability, are sensitive to antibiotics and toxic substances in wastewater, and are prone to cell loss, resulting in limited actual denitrification efficiency. Summary of the Invention

[0003] To address the above problems, this invention provides an integrated catalytic biofilm composite and a wastewater denitrification treatment method.

[0004] This invention is achieved through the following technical solution: An integrated catalytic biomembrane composite was prepared by the following method: The photocatalytic carrier was immersed in a heterotrophic nitrifying aerobic denitrifying bacteria solution and adsorbed at 25℃~30℃ for 6 to 12 hours to obtain a bacteria-carrier complex.

[0005] The bacterial-carrier complex was then immersed in a cross-linking solution containing sodium alginate and calcium chloride for cross-linking to form an integrated catalytic biofilm complex with gel embedding; the volume ratio of the bacterial-carrier complex to the cross-linking solution was 1:5~10.

[0006] The preparation method of the photocatalytic support is as follows: Urea or melamine is calcined at 520℃~560℃ for 2 to 4 hours to obtain basic g-C3N4.

[0007] The base g-C3N4 and the phosphorus source are mixed at a mass ratio of 1:0.05~0.15 and then calcined at 450℃~500℃ for 1~2 hours to obtain Pg-C3N4.

[0008] Pg-C3N4 was dispersed in an aminosilane coupling agent and reacted at 60℃~80℃ for 4 to 6 hours to obtain a surface-aminated functional material. The surface-aminated functional material was then loaded onto porous carbon fiber cloth through electrostatic self-assembly to form a photocatalytic support.

[0009] Preferably, the heterotrophic nitrifying aerobic denitrifying bacteria are selected from Rhodococcus rubrum (… Rhodococcus erythropolis ) and Pseudomonas spp. ( Pseudomonas sp. One or more of the following.

[0010] Preferably, the heterotrophic nitrifying aerobic denitrifying bacteria broth has an OD value of 1.0~1.2 at 600nm.

[0011] Preferably, the phosphorus source can be any one of diammonium hydrogen phosphate, ammonium phosphate, sodium hypophosphite, and triphenylphosphine.

[0012] Preferably, the aminosilane coupling agent can be any one of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-aminoethyl-γ-aminopropyltrimethoxysilane, N-aminoethyl-γ-aminopropylmethyldimethoxysilane, and bis(γ-aminopropyl)tetraethoxysilane.

[0013] Preferably, the mass-volume ratio of sodium alginate in the crosslinking solution is 2%, and the mass-volume ratio of calcium chloride is 2%.

[0014] Preferably, the crosslinking temperature is 4°C and the crosslinking time is 2 to 4 hours.

[0015] Preferably, the porous carbon fiber cloth has a size of 5cm × 5cm and a loading of 1.2mg / cm². 2 ~1.5mg / cm 2 .

[0016] A wastewater denitrification treatment method involves passing wastewater into a photobioreactor equipped with the integrated catalytic biofilm composite, and operating it continuously or intermittently under visible light irradiation and controlled dissolved oxygen conditions to achieve simultaneous removal of nitrogen pollution and antibiotics.

[0017] The visible light source has a wavelength of 420nm~480nm and a light intensity of 50μmol·m. -2 ·s -1 ~200 μmol·m -2 ·s -1 .

[0018] The dissolved oxygen is controlled at 2 mg / L to 4 mg / L, and the hydraulic retention time is 6 hours to 12 hours.

[0019] Preferably, the photobioreactor is a tubular photobioreactor, comprising: The reactor body (1) has an LED visible light source (3) wrapped around its outer wall; the reactor body (1) is filled with an integrated catalytic biofilm composite (2) with a filling rate of 30%~50%; the reactor body (1) is equipped with an aeration strip (11) and a dissolved oxygen controller (4). The reactor body (1) is provided with an inlet (12) at the upper end and an outlet (13) at the lower end. An air pump (5) is connected in series to an aeration device (10) via a flow meter (6), a precision needle valve (7), a valve (8), and an air filter (9). The aeration device (10) is connected to the aeration strip (11).

[0020] Compared with the prior art, the present invention has the following beneficial effects: In terms of material design and function, phosphorus-doped and surface-amino-modified gC3N4 achieved efficient docking with the heterogeneous photocatalytic carrier and the electron transport chain of HNAD bacteria, significantly improving the transfer efficiency of photogenerated electrons to the bacteria, thereby enhancing the activity of key denitrification enzymes. Regarding system construction, a visible light-driven spatiotemporal synergistic reaction system of "photobacteria" was formed, achieving precise matching between light energy input and microbial metabolic processes, maintaining efficient and stable denitrification performance even under low carbon source or high load conditions. In terms of operation and control, a multi-parameter synergistic intelligent control method for photohydraulic dissolved oxygen based on influent water quality was established, greatly enhancing the system's adaptability to water quality fluctuations and operational stability. The system also possesses good anti-interference and self-purification capabilities, selectively adsorbing and degrading inhibitors such as antibiotics through surface defect sites, protecting HNAD bacteria from oxidative damage while achieving system self-purification, thus improving its tolerance in complex wastewater environments. Furthermore, this solution boasts outstanding energy efficiency and long-term effectiveness. Utilizing visible-light-responsive non-metallic catalytic materials, it eliminates the need for an ultraviolet light source, significantly reducing energy consumption. Through a material-microbial co-immobilization design, it effectively prevents the loss of microorganisms and nanomaterials, ensuring long-term stable system operation. Ultimately, this technology is the first to systematically couple photocatalytic microorganisms for the deep denitrification and simultaneous antibiotic removal in complex systems such as aquaculture wastewater, providing a highly efficient and green integrated solution for the treatment of high-nitrogen, high-resistance wastewater. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a tubular photobioreactor used in this invention. Detailed Implementation

[0023] To facilitate understanding of the present invention, a more comprehensive description is provided below, along with preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this invention and in its specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0025] The chemical raw materials used in this invention, including urea, melamine, diammonium hydrogen phosphate, triphenylphosphine, and aminosilane coupling agents such as γ-aminopropyltriethoxysilane (KH-550), are all commonly used chemical raw materials or reagents in the field and can be obtained through commercial channels from common suppliers such as Sinopharm Chemical Reagent Co., Ltd. and Aladdin Reagent (Shanghai) Co., Ltd. Porous carbon fiber cloth can also be customized or purchased commercially. Those skilled in the art, based on the description of this invention, can obtain these raw materials and implement this invention without any inventive effort.

[0026] This invention provides a visible light-driven photocatalytic-heterotrophic nitrifying aerobic denitrifying bacteria coupled denitrification complex and a wastewater denitrification method. The core of this method lies in constructing an electron transfer coupling mechanism between a non-metallic photocatalytic carrier and HNAD bacteria. The technical solution mainly includes the following components:

[0027] (1) Preparation and functionalization of specific photocatalytic supports. Using graphitic carbon nitride (g-C3N4) as the base material, a photocatalytic support with visible light response and matching electron transport chain of HNAD bacteria was obtained through element doping and surface modification.

[0028] (2) Construction of material-strain immobilization system. The functionalized material g-C3N4 and the selected HNAD bacteria were co-immobilized using a biocompatible carrier to form a stable integrated catalytic biofilm.

[0029] (3) Design and operation of visible light driven coupling system. Design a reaction system with specific light intensity, wavelength modulation and dissolved oxygen control functions to achieve spatiotemporal synergy between photocatalysis and microbial metabolism.

[0030] (4) Optimization and control of operating parameters. Establish a method for regulating the operating parameters of light-bacteria coupled denitrification based on wastewater quality characteristics.

[0031] The working principle of this invention is based on the following collaborative mechanism: (1) Mechanism of photogenerated electron transport promotion. Visible light excites Pg-C3N4 to generate photogenerated electron-hole pairs. Photogenerated electrons are efficiently transferred to the electron transport chain of HNAD bacteria cell membrane through amino-modified surfaces. Electron transport promotes the activity of key enzymes (such as nitrite reductase and nitrate reductase), accelerating the nitrogen conversion process.

[0032] (2) Selective ROS generation mechanism.

[0033] Photogenerated holes react with surface-adsorbed water molecules to generate ·OH. Antibiotic molecules are selectively adsorbed at defect sites designed on the material surface, achieving targeted degradation of ROS. The ROS generation rate is regulated through material surface modification, avoiding oxidative damage to HNAD bacteria.

[0034] (3) Carrier immobilization and synergistic mechanism.

[0035] Porous carbon fiber cloth provides a large specific surface area, promoting bacterial adhesion and mass transfer. The gel embedding layer protects the bacteria from hydraulic shear while allowing small molecules to diffuse freely.

[0036] The beneficial effects of the present invention will be illustrated below through specific embodiments.

[0037] Example 1: Preparation method of photocatalytic support The specific preparation method is as follows: Material synthesis: Urea was used as a precursor and calcined in a muffle furnace at 520°C for 2 hours to obtain basic g-C3N4.

[0038] Basic g-C3N4 was mixed with diammonium hydrogen phosphate at a mass ratio of 1:0.05 and calcined twice at 450℃ for 1 hour to obtain phosphorus-doped g-C3N4, namely Pg-C3N4.

[0039] Surface functionalization: All obtained Pg-C3N4 were dispersed in the aminosilane coupling agent APTES (γ-aminopropyltriethoxysilane) and reacted at 60℃ for 4 hours to obtain the surface-aminated functional material, P-amino-g-C3N4. The obtained P-amino-g-C3N4 was dispersed in deionized water, and the pH was adjusted to 6.5 to prepare a dispersion with a concentration of 0.8 mg / mL. 100 mL of this dispersion was taken, and porous carbon fiber cloth cut into 5 cm × 5 cm pieces with a thickness of 2 mm was immersed in the dispersion and allowed to stand for 4 hours. After removal, it was rinsed with deionized water and dried at 55℃ to obtain the photocatalytic support with a loading of 1.2 mg / cm².

[0040] Example 2: Preparation method of photocatalytic support The specific preparation method is as follows: Material synthesis: Melamine was used as a precursor and calcined in a muffle furnace at 560°C for 4 hours to obtain basic g-C3N4.

[0041] Basic g-C3N4 was mixed with diammonium hydrogen phosphate at a mass ratio of 1:0.15 and calcined twice at 500℃ for 2 hours to obtain phosphorus-doped g-C3N4, namely Pg-C3N4.

[0042] Surface functionalization: Pg-C3N4 was dispersed in the aminosilane coupling agent APTES (γ-aminopropyltriethoxysilane) and reacted at 80℃ for 6 hours to obtain the surface-aminated functional material, P-amino-g-C3N4. The obtained P-amino-g-C3N4 was dispersed in deionized water, and the pH was adjusted to 7.0 to prepare a dispersion with a concentration of 1 mg / mL. 100 mL of this dispersion was taken, and porous carbon fiber cloth cut to 5 cm × 5 cm with a thickness of 2 mm was immersed in the dispersion and allowed to stand for 6 hours. After removal, it was rinsed with deionized water and dried at 60℃ to obtain the photocatalytic support with a loading of 1.5 mg / cm³. 2 This forms a photocatalytic carrier.

[0043] It should be noted that during the preparation of the photocatalytic support: Photocatalytic supports can be prepared when the phosphorus source is ammonium phosphate, sodium hypophosphite, or triphenylphosphine.

[0044] These substances each have their own characteristics. For example, diammonium hydrogen phosphate, i.e., (NH4)2HPO4, has good thermal stability and a moderate thermal decomposition temperature, which is conducive to the uniform incorporation of phosphorus into the g-C3N4 lattice; ammonium phosphate, i.e., (NH4)3PO4, has a high phosphorus content and significant doping efficiency, making it suitable for industrial-scale mass production; sodium hypophosphite, i.e., NaH2PO2, has reducing properties and can inhibit excessive oxidation of g-C3N4 during calcination; triphenylphosphine, i.e., C 18 H 15Organic phosphorus sources (P-type phosphorus sources) are suitable for low-temperature doping systems and help maintain the structural integrity of materials. Potassium hexafluorophosphate (KPF6), by introducing fluorine, can synergistically enhance the hydrophilicity and photocatalytic activity of the material surface. The phosphorus sources mentioned above are all suitable for phosphorus doping, possibly due to factors such as their phosphorus content, thermal stability, and compatibility with g-C3N4.

[0045] In the surface amination modification step, except for APTES (γ-aminopropyltriethoxysilane), any of the following aminosilane coupling agents can be used to prepare a photocatalytic support: KH-550 (γ-aminopropyltrimethoxysilane) is similar to APTES, but with a faster methoxyl hydrolysis rate, making it suitable for rapid immobilization.

[0046] KH-540 (N-aminoethyl-γ-aminopropyltrimethoxysilane) contains a double amino structure, which can provide more surface amino sites and enhance electrostatic adsorption with bacteria.

[0047] KH-792 (N-aminoethyl-γ-aminopropylmethyldimethoxysilane) contains long-chain amino groups in its molecular structure, which is beneficial for forming a more stable organic-inorganic interface.

[0048] Bis-APTES (bis(γ-aminopropyl)tetraethoxysilane), with its bifunctional design, can enhance crosslinking density and improve the mechanical strength of immobilized composites.

[0049] Example 3: Screening and scale-up culture of HNAD bacteria Strain source: Highly efficient HNAD bacteria were screened from activated sludge in aquaculture wastewater treatment systems. Through nitrogen source utilization experiments, strains with high efficiency in removing both ammonia nitrogen and nitrate nitrogen were selected.

[0050] The Rhodococcus rubrum used in this invention ( Rhodococcus erythropolis Strain Y10: Published in the literature "Nitrogen metabolism characteristics of Rhodococcus erythropolis Y10 and the influence of heavy metal ions on its denitrification [D]. Hunan Agricultural University, 2021."

[0051] Expanded culture: Rhodococcus rubrum ( Rhodococcus erythropolis Y10 strain was inoculated into enrichment medium containing the following components (per liter): Trisodium citrate: 5g; (NH4)2SO4: 0.4g or NaNO3: 0.6g; KH2PO4: 2g; K2HPO4: 6g; MgSO4·7H2O: 0.4g.

[0052] Trace element solution: 1 mL; Add water to a total volume of 1L.

[0053] Incubate at 30°C, pH 6, and 120 rpm in a shaker for 24 hours until the logarithmic growth phase.

[0054] Example 4: Screening and scale-up culture of HNAD bacteria Strain source: Highly efficient HNAD bacteria were screened from activated sludge in aquaculture wastewater treatment systems. Through nitrogen source utilization experiments, strains with high efficiency in removing both ammonia nitrogen and nitrate nitrogen were selected.

[0055] The *Pseudomonas* genus used in this invention ( Pseudomonas sp. F33 strain: Published in "Huang Shiwei. Pseudomonas ( Pseudomonas sp Preliminary Study on Nitrogen Metabolism Characteristics of F33 and Biofortified Denitrification Technology for Pig Wastewater [D]. Hunan Agricultural University, 2022. Expanded culture: Pseudomonas spp. ( Pseudomonas sp. F33 strain was inoculated into enrichment medium containing the following components (per liter): trisodium citrate: 8 g; (NH4)2SO4: 0.6g or NaNO3: 0.8g; KH2PO4: 4g; K2HPO4: 8g; MgSO4·7H2O: 0.6g; Trace element solution: 2 mL; Add water to a total volume of 1L.

[0056] Incubate at 35℃, pH 7.2, and 150 rpm on a shaker for 48 hours until the logarithmic growth phase.

[0057] Example 5: Integrated Catalytic Biomembrane Composite The specific preparation method is as follows: 1. Cell adsorption: The photocatalytic support (two pieces of porous carbon fiber cloth, 2 mm thick and 5 cm × 5 cm, loaded with P-amino-g-C3N4) prepared in Example 1 was immersed in Rhodococcus rubrum cultured to the logarithmic growth phase. Rhodococcus erythropolis In the Y10 strain suspension (the suspension obtained by the method described in Example 3, OD...) 600 =1.0), and adsorbed at 30℃ under static conditions for 12 hours to allow the bacteria to fully adhere to the surface and pores of the photocatalytic carrier, thus obtaining a "bacteria-carrier complex".

[0058] 2. Gel embedding: Prepare a crosslinking solution containing sodium alginate (2%, by volume, i.e., 2g sodium alginate dissolved in 100mL water) and calcium chloride (2%, by volume, i.e., 2g calcium chloride dissolved in 100mL water). Completely immerse the "bacterial-carrier complex" obtained in step 1 in a sufficient amount of the crosslinking solution, ensuring the volume of the crosslinking solution is 5 times the total volume of the "bacterial-carrier complex" to guarantee uniform crosslinking and sufficient mass transfer. Crosslink and cure at 4°C for 2 hours. During this process, sodium alginate and calcium chloride... 2+ Cross-linking forms a hydrogel, which encapsulates the bacteria and the photocatalytic carrier, and firmly fixes the bacteria on the photocatalytic carrier, forming the final "integrated catalytic biofilm complex".

[0059] 3. Post-processing: Take out the prepared integrated catalytic biofilm composite, gently rinse it with sterile physiological saline to remove unfixed bacteria and excess gel on the surface, and set it aside for later use.

[0060] Example 6: Integrated Catalytic Biomembrane Complex The specific preparation method is as follows: 1. Bacterial adsorption: The photocatalytic support (two pieces of porous carbon fiber cloth, 2 mm thick and 5 cm × 5 cm, loaded with P-amino-g-C3N4) prepared in Example 2 was immersed in Pseudomonas spp. in the logarithmic growth phase. Pseudomonas sp. F33 strain suspension (strain suspension obtained by the method described in Example 4, OD) 600 =1.2), and adsorbed at 30℃ under static conditions for 12 hours to allow the bacteria to fully adhere to the surface and pores of the photocatalytic carrier, thus obtaining a "bacteria-carrier complex".

[0061] 2. Gel embedding: Prepare a crosslinking solution containing sodium alginate (2%, by volume, i.e., 2g sodium alginate dissolved in 100mL water) and calcium chloride (2%, by volume, i.e., 2g calcium chloride dissolved in 100mL water). Completely immerse the "bacterial-carrier complex" obtained in step 1 in a sufficient amount of the crosslinking solution, ensuring the volume of the crosslinking solution is 10 times the total volume of the "bacterial-carrier complex" to guarantee uniform crosslinking and sufficient mass transfer. Crosslink and cure at 4°C for 4 hours. During this process, sodium alginate and calcium chloride... 2+ Cross-linking forms a hydrogel, which encapsulates the bacteria and the photocatalytic carrier, and firmly fixes the bacteria on the photocatalytic carrier, forming the final "integrated catalytic biofilm complex".

[0062] 3. Post-processing: Take out the prepared immobilized complex, rinse it gently with sterile physiological saline to remove unfixed bacteria and excess gel on the surface, and set aside for later use.

[0063] Example 7: A wastewater denitrification treatment method Design a tubular photobioreactor with an adjustable LED visible light source (wavelength 420nm, light intensity 50μmol·m²) installed on the inner wall of the reactor. -2 ·s -1 The reactor was filled with the integrated catalytic biofilm composite prepared in Example 5, with a filling rate of 30%. The system was equipped with an online dissolved oxygen monitoring and control device to maintain DO at 2 mg / L.

[0064] Operating method: Wastewater enters from the left side of the photobioreactor and flows out from the bottom.

[0065] Phase 1 (Start-up period, 7 days): Low-load water intake (simulating aquaculture wastewater diluted 1 times, then diluted with water), continuous light, HRT=12h, to allow the integrated catalytic biofilm complex to adapt to the wastewater environment.

[0066] Phase Two (Stabilization Period, 6 days): After the start-up period, increase the influent concentration according to the following gradient: First, adjust the influent to a 0.5-fold dilution and run for 2 days; then adjust the influent to a 0.25-fold dilution and run for 2 days; finally, adjust the influent to undiluted raw water (0-fold dilution, i.e., 100% raw water concentration) and run for 2 days, using a 12-hour light / 12-hour dark cycle, with HRT=8 hours.

[0067] Phase 3 (High-efficiency period, 7 days): After the stabilization period, the operating parameters will be adjusted to continuous illumination, HRT=6h, to reach the maximum nitrogen removal load.

[0068] Key terms and conditions definitions: Raw water: refers to simulated or actual wastewater that has not undergone pretreatment, and its core characteristic component is NH4. + -N concentration range: 95 mg / L~105 mg / L; NO3 - -N concentration range of 45 mg / L to 55 mg / L, and contains trace amounts (0.5 mg / L to 2.0 mg / L) of sulfonamide antibiotics (sulfadimidine).

[0069] This implementation method uses a laboratory-assembled photobioreactor system, such as... Figure 1 As shown: The reactor body 1 has an LED visible light source 3 wrapped around its outer wall; the reactor body 1 is filled with the integrated catalytic biofilm composite 2 prepared in Example 5, with a filling rate of 30%; a rectangular aeration strip 11 is installed on the reactor body 1; the upper end of the reactor body 1 is connected through to the dissolved oxygen probe of the dissolved oxygen controller 4; the upper end of the reactor body 1 is also provided with an inlet 12 and the lower end with an outlet 13; both the inlet 12 and the outlet 13 are provided with valves.

[0070] An air pump 5 is connected in series to an aeration device 10 via a flow meter 6, a precision needle valve 7, a valve 8, and an air filter 9. The aeration device 10 is connected to the aeration strip 11. The air inlet of the air filter 9 is connected to the air outlet of the valve 8, and the air outlet is connected to the air inlet of the aeration device 10.

[0071] The reactor body 1 is a custom-made cylindrical quartz glass tube with an effective volume of 10L (typical specifications: tube diameter Φ120mm, tube height 900mm); the LED visible light source 3 uses a dimmable COB silicone waterproof LED strip (purchased from Zhongshan Hongmeng Lighting Co., Ltd.), with a custom blue light band (main wavelength 420nm), evenly wrapped around the outer wall of the reactor, and the light intensity is controlled at 50μmol•m through a dimmer. -2 •s -1 Adjustable within the range; aeration device 10 is a microporous aeration device (titanium alloy microporous aeration head, pore size 0.5μm); air pump 5 is a silent oil-free air pump (Haili ACO series); flow meter 6 is a gas rotor flow meter (range 40L / h); dissolved oxygen controller 4 is an online dissolved oxygen controller, using Hongrun NHR-DO20A series fluorescence dissolved oxygen controller (Fujian Shunchang Hongrun Precision Instruments Co., Ltd.), which has 4mA analog output and RS485 communication function, can be linked with the system, and accurately maintains dissolved oxygen at 2mg / L. Dissolved oxygen controller 4 has a dissolved oxygen probe. Precision needle valve 7, valve 8 and air filter 9 are common commercially available products.

[0072] The aeration device 10 installed at the bottom of the reactor controls the aeration rate through an air pump 5, a flow meter 6, a precision needle valve 7, and a valve 8. The dissolved oxygen concentration is monitored and adjusted in real time by a dissolved oxygen controller 4. The air filter 9 is used by the air pump 5 to draw air from the environment and pump it into the reactor. The ambient air contains impurities such as dust, bacteria, and oil mist. If the air is not filtered, these impurities will clog the downstream aeration device 10, pollute the water in the reactor, and may introduce other bacteria that interfere with the activity of HNAD bacteria.

[0073] The precision needle valve 7 is responsible for fine adjustment, and together with the valve 8, which is responsible for coarse adjustment or on / off control, they achieve precise control of the aeration volume.

[0074] Example 8: A wastewater denitrification treatment method Design a tubular photobioreactor with an adjustable LED visible light source (wavelength 480nm, light intensity 200μmol·m⁻¹) installed on the inner wall of the reactor. -2 ·s -1 The reactor was filled with the integrated catalytic biofilm composite prepared in Example 6, with a filling rate of 50%. The system was equipped with an online dissolved oxygen monitoring and control device to maintain DO at 4 mg / L.

[0075] Operating method: Wastewater enters from the left side of the photobioreactor and flows out from the bottom.

[0076] Phase 1 (Start-up period, 7 days): Low-load water intake (simulating aquaculture wastewater diluted 1 times, then diluted with water), continuous light, HRT=12h, to allow the integrated catalytic biofilm complex to adapt to the wastewater environment.

[0077] Phase Two (Stabilization Period, 10 days): After the start-up period, increase the influent concentration according to the following gradient: First, adjust the influent to a 0.5-fold dilution and run for 3 days; then adjust the influent to a 0.25-fold dilution and run for 3 days; finally, adjust the influent to undiluted raw water (0-fold dilution, i.e., 100% raw water concentration) and run for 4 days, using a 12-hour light / 12-hour dark cycle, with HRT=8 hours.

[0078] Phase 3 (High-efficiency period, 10 days): After the stabilization period, the operating parameters will be adjusted to continuous illumination, HRT=6h, to reach the maximum nitrogen removal load.

[0079] Key terms and conditions definitions: Raw water: refers to simulated or actual wastewater that has not undergone pretreatment, and its core characteristic component is NH4. + -N concentration range: 95 mg / L~105 mg / L; NO3 - -N concentration range of 45 mg / L to 55 mg / L, and contains trace amounts (0.5 mg / L to 2.0 mg / L) of sulfonamide antibiotics (sulfadimidine).

[0080] This implementation method uses a laboratory-assembled photobioreactor system, such as... Figure 1 As shown: The reactor body 1 has an LED visible light source 3 wrapped around its outer wall; the reactor body 1 is filled with the integrated catalytic biofilm composite 2 prepared in Example 6, with a filling rate of 50%; a rectangular aeration strip 11 is installed on the reactor body 1; the upper end of the reactor body 1 is connected through to the dissolved oxygen probe of the dissolved oxygen controller 4; the upper end of the reactor body 1 is also provided with an inlet 12 and the lower end with an outlet 13; both the inlet 12 and the outlet 13 are provided with valves.

[0081] An air pump 5 is connected in series to an aeration device 10 via a flow meter 6, a precision needle valve 7, a valve 8, and an air filter 9. The aeration device 10 is connected to the aeration strip 11. The air inlet of the air filter 9 is connected to the air outlet of the valve 8, and the air outlet is connected to the air inlet of the aeration device 10.

[0082] The reactor body 1 is a custom-made cylindrical quartz glass tube with an effective volume of 10L (typical specifications: tube diameter Φ120mm, tube height 900mm); the LED visible light source 3 uses a dimmable COB silicone waterproof LED strip (purchased from Zhongshan Hongmeng Lighting Co., Ltd.), with a custom blue light band (main wavelength 480nm), evenly wrapped around the outer wall of the reactor, and the light intensity is controlled at 200μmol•m through a dimmer. -2 •s -1 Adjustable within the range; aeration device 10 is a microporous aeration device (titanium alloy microporous aeration head, pore size 0.5μm); air pump 5 is a silent oil-free air pump (Haili ACO series); flow meter 6 is a gas rotor flow meter (range 400L / h); dissolved oxygen controller 4 is an online dissolved oxygen controller, using the Hongrun NHR-DO20A series fluorescence dissolved oxygen controller (Fujian Shunchang Hongrun Precision Instruments Co., Ltd.), which has 20mA analog output and RS485 communication function, can be linked with the system, and accurately maintains dissolved oxygen at 4mg / L. Dissolved oxygen controller 4 has a dissolved oxygen probe. Precision needle valve 7, valve 8 and air filter 9 are common commercially available products.

[0083] The aeration device 10 installed at the bottom of the reactor controls the aeration rate through an air pump 5, a flow meter 6, a precision needle valve 7, and a valve 8. The dissolved oxygen concentration is monitored and adjusted in real time by a dissolved oxygen controller 4. The air filter 9 is used by the air pump 5 to draw air from the environment and pump it into the reactor. The ambient air contains impurities such as dust, bacteria, and oil mist. If the air is not filtered, these impurities will clog the downstream aeration device 10, pollute the water in the reactor, and may introduce other bacteria that interfere with the activity of HNAD bacteria.

[0084] The precision needle valve 7 is responsible for fine adjustment, and together with the valve 8, which is responsible for coarse adjustment or on / off control, they achieve precise control of the aeration volume.

[0085] Example 9, Typical Application Example Take the simulated treatment of aquaculture wastewater as an example.

[0086] Characteristics of simulated aquaculture wastewater: NH4 + -N concentration: 100 mg / L; NO3 - -N concentration: 50 mg / L; COD: 500 mg / L; contains trace amounts of antibiotics (sulfadiazine 1 mg / L).

[0087] System startup and operation: Wastewater denitrification was performed using the tubular photobioreactor in Example 7. The reactor was filled with the integrated catalytic biofilm composite prepared in Example 5, with a filling rate of 30%. The specific treatment method is as follows.

[0088] Phase 1 (Start-up period, 7 days): Low-load water intake (simulating aquaculture wastewater diluted 1 times, then diluted with water), continuous light, HRT=12h, to allow the integrated catalytic biofilm complex to adapt to the wastewater environment.

[0089] Phase Two (Stabilization Period, 6 days): After the start-up period, increase the influent concentration according to the following gradient: First, adjust the influent to a 0.5-fold dilution and run for 2 days; then adjust the influent to a 0.25-fold dilution and run for 2 days; finally, adjust the influent to undiluted raw water (0-fold dilution, i.e., 100% raw water concentration) and run for 2 days, using a 12-hour light / 12-hour dark cycle, with HRT=8 hours.

[0090] Phase 3 (High-efficiency period, 7 days): After the stabilization period, the operating parameters will be adjusted to continuous illumination, HRT=6h, to reach the maximum nitrogen removal load.

[0091] Principle of consistency of operating parameters: In the comparative experiment, except for the characteristic variable being investigated (photocatalytic carrier), the experimental group and the control group maintained consistency in all environmental and operating parameters, including strain source, carrier base material, reactor hydraulic conditions, influent water quality, temperature, and pH.

[0092] Effect evaluation formula The formulas for calculating denitrification efficiency (η_N) and antibiotic removal rate (η_Ab) are as follows: η_N=(C_in-C_out) / C_in×100%.

[0093] η_Ab=(C_in-C_out) / C_in×100%.

[0094] Where C_in is the concentration of the target substance in the influent, and C_out is the concentration of the target substance in the effluent.

[0095] The increase or decrease rate is calculated by comparing the η or C_out values ​​of the experimental group and the control group.

[0096] I. Effect Verification and Comparative Experiment To accurately evaluate the synergistic effect of the integrated catalytic biomembrane complex of the present invention, a rigorous parallel control experiment was set up.

[0097] (1) Experimental group (the wastewater denitrification treatment method of the present invention) Reactor composition: The tubular photobioreactor in Example 7 was used for wastewater denitrification treatment. The reactor was filled with the integrated catalytic biofilm composite prepared in Example 5, with a filling rate of 30%.

[0098] Operating parameters: Measured after the stable operation of the "high-efficiency period" has ended, i.e., continuous illumination, HRT=6h.

[0099] Test results: The average ammonia nitrogen concentration in the system effluent was 2.1 mg / L, and the average sulfadiazine concentration was 0.28 mg / L.

[0100] (2) Control group (HNAD bacteria bioreactor alone) Reactor composition: Except for not containing any photocatalytic carrier, its carrier material, HNAD inoculation species and concentration, reactor configuration and volume are exactly the same as those of the experimental group.

[0101] Operating parameters: Stable operation and measurements were conducted under the same conditions as the experimental group, including the same influent water quality, the same HRT (6h), and the same continuous light exposure. This was to ensure that the only variable was "whether or not a photocatalytic carrier was added".

[0102] Test results: The average ammonia nitrogen concentration in the system effluent was 3.6 mg / L, and the average sulfadiazine concentration was 1.0 mg / L.

[0103] (3) Comparison and calculation of effects Nitrogen removal efficiency improvement rate: The nitrogen removal rate of the experimental group = (50-2.1) / 50×100% = 95.8%.

[0104] The denitrification rate of the control group = (50-3.6) / 50×100% = 92.8%.

[0105] Improvement rate = (95.8% - 92.8%) / 92.8% × 100% ≈ 41%.

[0106] Antibiotic residue reduction rate: The removal rate of the experimental group = (1.0 - 0.28) / 1.0 × 100% = 72%.

[0107] The removal rate of the control group = (1.0-1.0) / 1.0×100% = 0% (indicating that HNAD bacteria alone have no significant degradation effect on this antibiotic).

[0108] The reduction rate = (1.0 - 0.28) / 1.0 × 100% = 72% (that is, the antibiotic residue in the effluent was reduced by 72%).

[0109] It should be noted that the wastewater denitrification treatment method described in Example 8 was used in a practical application experiment, and the results were the same as those in Example 9, indicating that the integrated catalytic biofilm composite of the present invention not only significantly improves the denitrification performance, but also achieves efficient degradation of antibiotics.

[0110] The above data fully demonstrates that the photocatalytic carrier introduced in this invention forms a highly efficient synergistic system with HNAD bacteria. Under the same conditions, it not only significantly improves denitrification performance but also achieves highly efficient degradation of antibiotics, which cannot be achieved by biological treatment alone.

[0111] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0112] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this invention should be determined by the appended claims.

Claims

1. An integrated catalytic biomembrane composite, characterized in that, It is prepared by the following method: The photocatalytic carrier was immersed in a heterotrophic nitrifying aerobic denitrifying bacteria solution and adsorbed at 25℃~30℃ for 6 hours~12 hours to obtain a bacteria-carrier complex. The bacterial-carrier complex was then immersed in a cross-linking solution containing sodium alginate and calcium chloride for cross-linking to form an integrated catalytic biofilm complex with gel embedding; the volume ratio of the bacterial-carrier complex to the cross-linking solution was 1:5~10. The preparation method of the photocatalytic support is as follows: Urea or melamine is calcined at 520℃~560℃ for 2 hours to 4 hours to obtain basic g-C3N4; The base g-C3N4 and the phosphorus source are mixed at a mass ratio of 1:0.05~0.15 and then calcined at 450℃~500℃ for 1~2 hours to obtain Pg-C3N4. Pg-C3N4 was dispersed in an aminosilane coupling agent and reacted at 60℃~80℃ for 4 to 6 hours to obtain a surface-aminated functional material. The surface-aminated functional material was then loaded onto porous carbon fiber cloth through electrostatic self-assembly to form a photocatalytic support.

2. The integrated catalytic biomembrane composite according to claim 1, characterized in that, The heterotrophic nitrifying aerobic denitrifying bacteria are selected from Rhodococcus rubrum (… Rhodococcus erythropolis ) and Pseudomonas spp. ( Pseudomonas sp. One or more of the following.

3. The integrated catalytic biomembrane composite according to claim 1, characterized in that, The heterotrophic nitrifying aerobic denitrifying bacteria broth has an OD value of 1.0~1.2 at 600nm.

4. The integrated catalytic biomembrane composite according to claim 1, characterized in that, The phosphorus source can be any one of diammonium hydrogen phosphate, ammonium phosphate, sodium hypophosphite, and triphenylphosphine.

5. The integrated catalytic biomembrane composite according to claim 1, characterized in that, The aminosilane coupling agent can be any one of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-aminoethyl-γ-aminopropyltrimethoxysilane, N-aminoethyl-γ-aminopropylmethyldimethoxysilane, and bis(γ-aminopropyl)tetraethoxysilane.

6. The integrated catalytic biomembrane composite according to claim 1, characterized in that, The crosslinking solution contains 2% sodium alginate by mass and 2% calcium chloride by mass and volume.

7. The integrated catalytic biomembrane composite according to claim 1, characterized in that, The cross-linking temperature is 4°C, and the cross-linking time is 2 to 4 hours.

8. The integrated catalytic biomembrane composite according to claim 1, characterized in that, The porous carbon fiber cloth has a size of 5cm × 5cm and a loading capacity of 1.2mg / cm². 2 ~1.5mg / cm 2 .

9. A wastewater denitrification treatment method, characterized in that, Wastewater is fed into a photobioreactor equipped with the integrated catalytic biofilm composite as described in claim 1, and the reactor is operated continuously or intermittently under visible light irradiation and controlled dissolved oxygen conditions to achieve the simultaneous removal of nitrogen pollution and antibiotics. The visible light source has a wavelength of 420nm~480nm and a light intensity of 50μmol·m. -2 ·s -1 ~200 μmol·m -2 ·s -1 ; The dissolved oxygen is controlled at 2 mg / L to 4 mg / L, and the hydraulic retention time is 6 hours to 12 hours.

10. The wastewater denitrification treatment method according to claim 9, characterized in that, The photobioreactor is a tubular photobioreactor, comprising: The reactor body (1) has an LED visible light source (3) wrapped around its outer wall; the reactor body (1) is filled with an integrated catalytic biofilm composite (2) with a filling rate of 30%~50%; the reactor body (1) is equipped with an aeration strip (11) and a dissolved oxygen controller (4). The reactor body (1) is provided with an inlet (12) at the upper end and an outlet (13) at the lower end. An air pump (5) is connected in series to an aeration device (10) via a flow meter (6), a precision needle valve (7), a valve (8), and an air filter (9). The aeration device (10) is connected to the aeration strip (11).

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