Autotrophic photocatalysis-algal-bacterial symbiosis integrated wastewater treatment device and method

Abstract

The invention discloses an autotrophic photocatalysis-algal-bacterial symbiosis integrated wastewater treatment device and method. The device comprises a photosynthetic reactor main body and an algal-bacterial symbiosis biological membrane assembly which is arranged in the photosynthetic reactor main body and comprises a hanging frame and a porous carrier hung on the hanging frame; the light source assembly comprises an LED light source and a sealed light-transmitting carrier arranged outside the LED light source, and the sealed light-transmitting carrier is detachably connected with the photosynthetic reactor main body; the chemical adding device is communicated with the photosynthetic reactor main body; and the PLC control system is used for controlling the starting of the LED light source and the adjustment of the illumination intensity. According to the method, a photocatalysis technology is introduced on the basis of a bacteria-algae symbiotic process, degradation-resistant organic matters are decomposed into intermediate products easy to biochemically treat through photocatalysis, further mineralization of the intermediate degradation products by microorganisms is facilitated, the degradation capacity of the microorganisms is enhanced, and meanwhile, algae can absorb nitrogen and phosphorus nutritive salts in wastewater and inhibit secondary pollution.

Description

Technical Field

[0001] This invention relates to the field of environmental protection technology, specifically to an autotrophic photocatalytic-bacterial-algae symbiotic integrated wastewater treatment device and method. Background Technology

[0002] In recent years, with the increasing detection of antibiotics such as sulfonamides and quinolones in water bodies, the resulting ecological risks and pollution control challenges have become a global focus. While traditional activated sludge processes (such as the CANON process) can effectively remove COD and ammonia nitrogen, they struggle to break down the aromatic and heterocyclic structures of antibiotic molecules, resulting in low antibiotic removal rates. This is accompanied by problems such as high aeration energy consumption, the need for external carbon sources, large sludge production, and the risk of secondary pollution. Furthermore, the long-term presence of antibiotics and other persistent organic matter inhibits microbial activity, further limiting biodegradation efficiency and creating a systemic bottleneck for traditional processes in addressing emerging pollutants.

[0003] To overcome these limitations, researchers attempted to couple the CANON process with a microbial-algae symbiotic system. This involved utilizing gas exchange (O2 / CO2) between microbes and algae to reduce aeration energy consumption and achieve carbon cycling, while simultaneously improving denitrification efficiency and recovering biomass resources through microalgae absorption of nitrogen and phosphorus nutrients. However, this coupled system still suffers from problems such as strong biomass shading after long-term operation, incomplete antibiotic degradation, and decreased treatment efficiency. In real-world aquatic environments, the long-term presence of many non-biodegradable or persistent organic pollutants can affect microbial growth, inhibiting biodegradation and reducing the treatment capacity of the microbial-algae symbiotic system, even leading to the death of microalgae. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an autotrophic photocatalytic-algae symbiotic integrated wastewater treatment device and a method for treating antibiotic-containing wastewater. This invention introduces photocatalytic technology into the algae symbiotic process. Compared to traditional algae symbiotic processes, photocatalysis decomposes recalcitrant organic matter into easily biochemically treatable intermediate products, facilitating further mineralization of these intermediate degradation products by microorganisms and enhancing their degradation capabilities. Simultaneously, algae can absorb nitrogen and phosphorus nutrients from the wastewater, inhibiting secondary pollution. This constructs a new sustainable wastewater treatment path towards "energy self-sufficiency" and "carbon neutrality."

[0005] To achieve the above objectives, the present invention employs the following technical solution: This invention provides an integrated autotrophic photocatalytic-algae symbiotic wastewater treatment device, comprising: The main body of the photosynthetic reactor is a light-transmitting container. The main body of the photosynthetic reactor is provided with an inlet, an outlet and at least one sampling port, and each sampling port is provided with a valve. A symbiotic biofilm component of bacteria and algae is disposed inside the main body of the photosynthetic reactor and includes a bracket and a porous carrier suspended on the bracket; A light source assembly is disposed inside the main body of the photosynthetic reactor and is used to provide illumination; the light source assembly includes an LED light source and a sealed light-transmitting carrier disposed outside the LED light source, and the sealed light-transmitting carrier is detachably connected to the main body of the photosynthetic reactor. The drug dosing device is connected to the inlet of the photosynthetic reactor body or the interior of the photosynthetic reactor body via a pipeline; The PLC control system is connected to the LED light source and the drug dosing device.

[0006] Furthermore, a heating rod and a temperature probe are installed inside the main body of the photosynthetic reactor; both the temperature probe and the heating rod are connected to the PLC control system. Furthermore, a pH probe for detecting water quality indicators is installed inside the main body of the photosynthetic reactor, and the pH probe is connected to the PLC control system. Furthermore, a DO probe is installed inside the main body of the photosynthetic reactor, and the DO probe is connected to the PLC control system.

[0007] Furthermore, the water inlet is located at the bottom of the photosynthetic reactor body, and the drain outlet is located in the middle of the photosynthetic reactor body; multiple sampling ports are spaced apart along the height direction of the photosynthetic reactor body. Furthermore, the main body of the photosynthetic reactor is a translucent cylindrical structure, made of transparent acrylic or transparent glass. Furthermore, the filling rate of the porous carrier is 15% to 25% of the effective volume of the main body of the photosynthetic reactor.

[0008] Furthermore, two sets of hanging racks are arranged at intervals along the height direction of the photosynthetic reactor body, and multiple sets of hanging lines are arranged between the two sets of hanging racks, with multiple porous carriers provided on the hanging lines.

[0009] Furthermore, the porous carrier is a polyurethane sponge carrier.

[0010] Furthermore, the bracket is made of stainless steel.

[0011] Furthermore, the hanging wire is a polyethylene wire.

[0012] Furthermore, the polyurethane sponge carrier is tetragonal in shape.

[0013] Furthermore, the LED light source is a variable LED light source with an adjustable illuminance in the range of 3000~8000 lux, and the PLC control system is configured to control the LED light source to operate periodically according to a preset light / dark time ratio, wherein the light / dark time ratio is 10h:14h to 14h:10h.

[0014] Furthermore, the main wavelength band of the emission spectrum of the LED light source includes blue light of 400-500nm and red light of 600-700nm.

[0015] Furthermore, the drug dosing device is used to add a photocatalyst into the main body of the photosynthetic reactor. The photocatalyst is g-C3N4 nanomaterial, and the dosing concentration is 0.1~0.5g / L.

[0016] Furthermore, the device also includes a solid-liquid separation device connected to the drain outlet of the main body of the photosynthetic reactor.

[0017] Furthermore, the inlet is connected to external wastewater via an inlet pipe, and a peristaltic pump and a rotor flow meter are installed on the inlet pipe; a drain pipe is connected to the outlet, and a timer and a drain solenoid valve are installed on the drain pipe, and the peristaltic pump, rotor flow meter, timer, and drain solenoid valve are all connected to the PLC system.

[0018] The present invention also provides a wastewater treatment method using the aforementioned apparatus, comprising the following steps: S1. System startup and biofilm formation: Autotrophic sludge and Chlorella in the logarithmic growth phase are inoculated into the main body of the photosynthetic reactor, and a stable bacterial-algal symbiotic biofilm is formed on the porous biological carrier. S2. Wastewater treatment: Wastewater is pumped into the main body of the photosynthetic reactor, and g-C3N4 photocatalyst at a concentration of 0.1~0.3g / L is added to the main body of the photosynthetic reactor through the reagent dosing device. S3. Sequential Batch Operation: The sequential batch operation mode of water intake, light reaction, sedimentation, and drainage is adopted, with a single cycle of 24 hours. During the light reaction stage, the LED light source is turned on, and the light intensity is controlled to maintain the dissolved oxygen concentration of the system at 1~3mg / L. During the sedimentation and drainage stages, the light source is turned off. S4. Continuous operation: Repeat steps S2 to S3 to achieve continuous wastewater treatment.

[0019] Furthermore, the wastewater contains antibiotics.

[0020] Furthermore, in step S1, the inoculation amount of the fully autotrophic sludge is 3~7 g / L, and the inoculation amount of Chlorella is 0.2~1.0 g / L.

[0021] Compared with the prior art, the advantages of this invention are as follows: 1. The wastewater treatment device of this invention utilizes a fully autotrophic sludge system to construct a microbial-algae symbiotic system. It offers advantages such as no need for external carbon sources and high denitrification efficiency, with significant coupling effects with microalgae. It achieves good treatment results without external aeration or carbon sources, allowing for aeration- and carbon-source-free wastewater treatment with optimized process parameters, resulting in energy conservation and emission reduction. The coupled photocatalytic process further enhances the removal efficiency of organic pollutants. The fully autotrophic microbial-algae symbiotic biofilm cultivated in this invention exhibits stronger long-term operational stability. The structure of the microalgae and photocatalyst material on the outer side of the fully autotrophic sludge within the carrier, cultivated in the form of a biofilm, possesses stronger resistance to water flow shear forces, effectively preventing sludge loss.

[0022] 2. The core advantage of this invention lies in the efficient coupling of photocatalysis, endogenous autotrophic denitrification, and bacterial-algal symbiosis to construct a synergistic micro-ecosystem. The photocatalytic process preferentially degrades recalcitrant pollutants such as antibiotics, eliminating their toxic inhibitory effects on microorganisms and creating favorable conditions for subsequent biological treatment. Meanwhile, the endogenous autotrophic bacteria and microalgae achieve carbon-oxygen cycling through endogenous gas exchange (O2 / CO2), simultaneously completing efficient denitrification and thorough mineralization of organic matter without the need for external organic carbon sources or mechanical aeration, fundamentally achieving the goals of energy conservation, emission reduction, and sludge reduction.

[0023] 3. Another significant advantage of this invention lies in its excellent operational stability. The functional microorganisms in the system are fixed on the porous carrier in the form of biofilm, forming a gradient structure in which "autotrophic sludge is enriched on the inner side of the carrier and microalgae and photocatalytic materials are attached on the outer side". This stable micro-ecological space not only greatly enhances the ability of the bacterial and algal community to resist the shear force of water flow and effectively avoids sludge loss, but also optimizes the material transfer and metabolic synergy through spatial order, thereby ensuring that the treatment device can maintain long-term, efficient and stable operation performance when facing water quality fluctuations. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the device of the present invention.

[0025] The following are the labels in the attached diagram: 1. Main body of photosynthetic reactor; 11. Inlet; 12. Outlet; 13. Sampling port; 14. Heating rod; 15. Temperature probe; 16. pH probe; 17. DO probe; 18. Peristaltic pump; 19. Rotor flow meter; 2. Algal-bacterial symbiotic biofilm assembly; 21. Hanger; 22. Hanging wire; 23. Porous carrier; 3. Light source assembly; 31. LED light source; 32. Sealed light-transmitting carrier; 4. Chemical dosing device; 5. PLC control system; 6. Solid-liquid separation device. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar words used in this invention specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connection" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0028] like Figure 1 As shown, the present invention provides an autotrophic photocatalytic-bacterial-algae symbiotic integrated wastewater treatment device, including a photosynthetic reactor body 1, a bacterial-algae symbiotic biofilm component 2, a light source component 3, a chemical dosing device 4, a PLC control system 5, and an external power supply for powering the device.

[0029] The photosynthetic reactor body 1 is a light-transmitting container. It has an inlet 11, an outlet 12, and at least one sampling port 13, with a valve on the sampling port 13. The algae-bacterial symbiotic biofilm assembly 2 is located inside the photosynthetic reactor body 1 and includes a bracket 21 and a porous carrier 23 suspended on the bracket 21 for algae biofilm formation. The light source assembly 3 is located inside the photosynthetic reactor body 1 and provides illumination. The light source assembly 3 includes an LED light source 31 and a sealed light-transmitting carrier 32 located outside the LED light source 31. The sealed light-transmitting carrier 32 is detachably connected to the photosynthetic reactor body 1, either by snap-fit ​​or threaded connection. After long-term operation, biomass will adhere to the outer wall of the sealed light-transmitting carrier 32, affecting light transmittance and impacting the normal growth of algae and bacteria and the photocatalytic effect on the algae-bacterial biofilm packing assembly. Therefore, this invention makes the sealed light-transmitting carrier 32 a detachable module for easy removal and cleaning. The drug dosing device 4 is connected to the inlet 11 of the photosynthetic reactor body 1 or the interior of the photosynthetic reactor body 1 via a pipeline, and is used to add photocatalyst and / or trace elements into the photosynthetic reactor body 1. The PLC control system 5 is connected to the LED light source 31 and the drug dosing device 4, and is used to control the start-up of the drug dosing device 4 and the LED light source 31, as well as the adjustment of the light intensity.

[0030] In some embodiments, a heating rod 14 and a temperature probe 15 are further provided inside the photosynthetic reactor body 1; both the temperature probe 15 and the heating rod 14 are electrically connected to the PLC control system 5; the PLC control system 5 can receive the temperature signal from the temperature probe 15, compare it with a preset temperature threshold, and then output a control signal to drive the heating rod 14 to start and stop, thereby controlling the water temperature inside the photosynthetic reactor body 1 within a preset range. Preferably, the preset range of water temperature is 28-32℃.

[0031] In some embodiments, a pH probe 16 for detecting water quality indicators is installed inside the photosynthetic reactor body 1. The pH probe 16 is connected to a PLC control system 5. The PLC control system 5 can control the chemical dosing device 4 to add acid-base regulators based on the pH data fed back by the pH probe 16, thereby stabilizing the pH value inside the photosynthetic reactor body 1 within the range of 7.0 to 8.0. Specifically, the PLC control system 5 receives the monitoring data from the pH probe 16 and compares it with the internally preset pH threshold range (7.0 to 8.0). Once a pH value deviates from this range, it automatically generates a control command to drive the chemical dosing device 4 to accurately add acid-base regulators such as acid or alkali solutions, thereby achieving closed-loop automatic control of the pH value inside the reactor and ensuring that the system always operates stably in a suitable acid-base environment.

[0032] In some embodiments, a dissolved oxygen (DO) probe 17 is installed inside the photosynthetic reactor body 1. The DO probe 17 is connected to a PLC control system 5. The PLC control system 5 can dynamically adjust the light intensity of the LED light source 31 based on the dissolved oxygen concentration data fed back by the DO probe, thereby stabilizing the dissolved oxygen concentration inside the photosynthetic reactor body 1 within the range of 1~3 mg / L. Specifically, the PLC control system 5 receives and processes the dissolved oxygen concentration data collected by the DO probe 17, compares it with a preset program and a set threshold (such as 1-3 mg / L), and then dynamically adjusts the light intensity or on / off state of the LED light source 31 based on the comparison result. This closed-loop control strategy precisely maintains the dissolved oxygen level inside the reactor within the optimal range required for microbial metabolism and pollutant degradation.

[0033] In some embodiments, the inlet 11 is located at the bottom of the photosynthetic reactor body 1, and the outlet 12 is located in the middle of the photosynthetic reactor body 1; multiple sampling ports 13 are provided at intervals along the height direction of the photosynthetic reactor body 1, so that during operation, samples can be taken from sampling ports 13 at different heights as needed to detect the wastewater treatment status.

[0034] In some embodiments, the photosynthetic reactor body 1 is a light-transmitting cylindrical structure, made of transparent acrylic or transparent glass, or other light-transmitting materials.

[0035] In some embodiments, the filling rate of the porous carrier 23 is 15% to 25% of the effective volume of the photosynthetic reactor body 1. For example, the filling rates of the porous carrier 23 are 15%, 17%, 19%, 20%, 22%, and 25%.

[0036] The effective volume of the photosynthetic reactor body 1 is the volume that the photosynthetic reactor body 1 can use to contain wastewater, microorganisms and carry out biochemical reactions during normal operation.

[0037] Filling rate = (volume of porous carrier 23 itself / effective volume of photosynthetic reactor body 1) × 100%.

[0038] In this embodiment, the filling rate of the porous carrier 23 is controlled at 15%~25%, which provides sufficient biofilm attachment surface area to enrich high concentrations of functional microorganisms and ensure full contact between pollutants and biomass. It also avoids water flow short-circuiting, dead zone formation, and increased mass transfer resistance caused by overfilling, thereby ensuring efficient transfer of dissolved oxygen, nutrients, and degradation products, laying the kinetic foundation for the photocatalytic-bacterial-algae synergistic degradation system. This ensures that the carrier can retain a sufficient amount of bacterial and algal biofilm to handle the degradation of high-load pollutants. Simultaneously, the appropriate filling density effectively reduces the risk of excessive collision and friction between carriers, significantly enhancing the biofilm's resistance to water flow shear forces, preventing excessive biofilm detachment and sludge loss, thus ensuring stable and efficient treatment performance during long-term continuous operation.

[0039] In some embodiments, two sets of the hangers 21 are arranged at intervals along the height direction of the photosynthetic reactor body 1, and multiple sets of hanging lines 22 are connected between the two sets of hangers 21, with multiple porous carriers 23 suspended on the hanging lines 22.

[0040] In some embodiments, the porous carrier 23 is a polyurethane sponge carrier.

[0041] In some embodiments, the bracket 21 is a stainless steel frame.

[0042] In some embodiments, the hanging wire 22 is a polyethylene wire.

[0043] In some embodiments, the polyurethane foam carrier is tetragonal in shape.

[0044] In some embodiments, the LED light source 31 is a variable LED light source 31 with an adjustable light intensity in the range of 3000~8000 lux. The PLC control system 5 is configured to control the LED light source 31 to operate periodically according to a preset light / dark time ratio, which is 10h:14h to 14h:10h. The device designed in this invention adopts a dynamic cyclic operation mode and constructs a heterotrophic-autotrophic alternating metabolic environment through an alternating substrate supply strategy. This system can achieve metabolic coupling between dissolved oxygen and carbon-containing gases, forming a molecular oxygen metabolism regeneration mechanism, so that the carbon fixation process of microalgae relies entirely on the carbon flow circulation within the system, significantly reducing the external carbon input requirement in traditional microalgae cultivation. This unique carbon-oxygen coupling characteristic not only achieves a reduction in carbon footprint, but also optimizes the reactor configuration from the perspective of process principle—eliminating the need for an aeration system and its supporting blower unit, saving more costs. In the symbiotic network of the composite bacterial-algae community, the extracellular polymers (EPS) and small molecule organic matter produced by heterotrophic bacteria metabolism can participate in microalgae photosynthesis as electron donors.

[0045] In some embodiments, the main wavelength band of the emission spectrum of the LED light source 31 includes blue light of 400-500nm and red light of 600-700nm.

[0046] In some embodiments, the drug dosing device 4 is used to add a photocatalyst into the photosynthetic reactor body 1. The photocatalyst is g-C3N4 nanomaterial and the dosing concentration is 0.1~0.5g / L.

[0047] In some embodiments, the device further includes a solid-liquid separation device 6 connected to the drain outlet 12 of the photosynthetic reactor body 1, to achieve algal liquid separation, clear liquid discharge, and algal biomass recycling.

[0048] In some embodiments, the inlet 11 is connected to external wastewater via an inlet pipe, and a peristaltic pump 18 and a rotor flow meter 19 are installed on the inlet pipe; a drain pipe is connected to the outlet 12, and a timer and a drain solenoid valve are installed on the drain pipe. The peristaltic pump 18, rotor flow meter 19, timer, and drain solenoid valve are all connected to a PLC system, thereby forming an integrated water inlet and drainage control unit. This unit can automatically realize precise control of water inlet flow, timed switching of reaction cycle, and precise execution of drainage operation according to a preset program or real-time feedback signal.

[0049] The present invention also provides a method for treating wastewater using the aforementioned device, comprising the following steps: S1. System startup and biofilm formation: Autotrophic sludge and Chlorella in the logarithmic growth phase are inoculated into the main body of the photosynthetic reactor 1, and a stable bacterial-algal symbiotic biofilm is formed on the porous biological carrier. S2. Wastewater treatment: Wastewater is pumped into the main body of the photosynthetic reactor 1, and g-C3N4 photocatalyst with a concentration of 0.1~0.3g / L is added to the main body of the photosynthetic reactor 1 through the chemical dosing device 4. S3. Sequential Batch Operation: The sequential batch operation mode of water intake, light reaction, sedimentation, and drainage is adopted, with a single cycle of 24 hours. During the light reaction stage, the LED light source 31 is turned on, and the light intensity is controlled to maintain the dissolved oxygen concentration of the system at 1~3mg / L. During the sedimentation and drainage stages, the light source is turned off. S4. Continuous operation: Repeat steps S2 to S3 to achieve continuous wastewater treatment.

[0050] Furthermore, the wastewater contains antibiotics. In step S1, the inoculation amount of the fully autotrophic sludge is 3-7 g / L, and the inoculation amount of Chlorella is 0.2-1.0 g / L. For example, the antibiotic in the wastewater is ciprofloxacin, with an initial concentration of 1-10 mg / L.

[0051] Example 1 This embodiment 1 provides an autotrophic photocatalytic-bacterial-algae symbiotic integrated wastewater treatment device, including a photosynthetic reactor body 1, a bacterial-algae symbiotic biofilm component 2, a light source component 3, a chemical dosing device 4, a heating rod 14, a temperature probe 15, a pH probe 16, a DO probe 17, and a PLC control system 5.

[0052] The main body 1 of the photosynthetic reactor is a sequencing batch reactor with a light-transmitting cylindrical structure, made of transparent acrylic or transparent plexiglass. The bottom of the main body 1 of the photosynthetic reactor is provided with a water inlet 11 and the middle is provided with a drain outlet 12. Multiple sampling ports 13 are arranged at intervals along the height direction of the main body 1 of the photosynthetic reactor, and each sampling port 13 is provided with a valve.

[0053] The algae-bacterial symbiotic biofilm component 2 is disposed inside the photosynthetic reactor body 1, including a bracket 21 and a porous carrier 23 suspended on the bracket 21. The bracket 21 is made of stainless steel. Two sets of brackets 21 are arranged at intervals along the height direction of the photosynthetic reactor body 1. Multiple sets of hanging wires 22 are arranged between the two sets of brackets 21. The hanging wires 22 are polyethylene wires. Multiple porous carriers 23 are provided on the hanging wires 22. The porous carriers 23 are cubic polyurethane sponge carriers. The filling rate of the porous carriers 23 is 15% to 25% of the effective volume of the photosynthetic reactor body 1.

[0054] The light source assembly 3 is disposed inside the photosynthetic reactor body 1 and is used to provide illumination. The light source assembly 3 includes an LED light source 31 and a sealed light-transmitting carrier 32 disposed outside the LED light source 31. The sealed light-transmitting carrier 32 is detachably connected to the photosynthetic reactor body 1. The LED light source 31 is a variable LED light source 31 with an adjustable light intensity in the range of 3000~8000 lux. The PLC control system 5 is configured to control the LED light source 31 to operate periodically according to a preset light / dark time ratio of 10h:14h to 14h:10h. The main wavelength band of the emission spectrum of the LED light source 31 includes blue light of 400-500nm and red light of 600-700nm.

[0055] The drug dosing device 4 is connected to the inlet 11 of the photosynthetic reactor body 1 or the interior of the photosynthetic reactor body 1 via a pipeline; the drug dosing device 4 is used to add a photocatalyst into the photosynthetic reactor body 1, the photocatalyst is g-C3N4 nanomaterial, and the dosing concentration is 0.1~0.5g / L.

[0056] The main body 1 of the photosynthetic reactor is equipped with a heating rod 14, a temperature probe 15, and a pH probe 16 and a DO probe 17 for detecting water quality indicators; the LED light source 31, the chemical dosing device 4, the temperature probe 15, the heating rod 14, the pH probe 16, and the DO probe 17 are all connected to the PLC control system 5.

[0057] Example 2 The apparatus described in Example 1 is used, wherein the inner diameter of the photosynthetic reactor body 1 is 12 cm, the effective height is 40 cm, and the effective volume is 4.5 L. Four rows of polyurethane sponges are fixed by polyethylene lines and evenly distributed in the photosynthetic reactor body as biofilm carriers (fill rate 20%). The side length, specific surface area, and specific gravity of each square polyurethane sponge are 3 cm², 15000 m² / m³, and 0.91 g / cm³, respectively. A magnetic stirrer is placed at the bottom of the photosynthetic reactor body to ensure uniform mixing of water and air. There are four ports along the photosynthetic reactor body for easy water effluent and sampling. The operating temperature of the photosynthetic reactor body is maintained at approximately 30°C using a heating rod 14. The influent and effluent are automatically controlled by a timer switch. The volume exchange rate of the photosynthetic reactor body is 50% per cycle.

[0058] A method for treating antibiotic-containing wastewater using an autotrophic photocatalytic-algae symbiotic integrated wastewater treatment device includes the following steps: S1, the start-up stage of the main body of the photosynthetic reactor 1, is to inoculate 5 g / L of fully autotrophic sludge and 0.2-1.0 g / L of Chlorella in the logarithmic growth phase, and to acclimate it until a symbiotic biofilm of bacteria and algae forms on the surface and pores of the sponge packing and becomes stable; S2. Simulated wastewater and antibiotic solution are pumped into the main body of the photosynthetic reactor 1 via an inlet pump. Photocatalyst is added simultaneously. A sequential batch process is adopted, including inlet, reaction, sedimentation, and drainage. The inlet and reaction processes are the illumination stage, with LED light source 31 turned on and the light intensity controlled at 5000 lux. The dissolved oxygen concentration of the system is adjusted to 1-3 mg / L. The sedimentation and drainage processes are the darkness stage, with the light / dark time ratio controlled at 12h:12h. S3. The treated wastewater is discharged through the discharge pipe in the middle of the main body 1 of the photosynthetic reactor and is then used for resource utilization through the solid-liquid separation device 6. S4. Repeat S2-S3 to continuously treat the wastewater.

[0059] In this Example 2, artificially simulated wastewater was used as the influent to the photosynthetic reactor to ensure the stability of the influent water quality and the accuracy of the experiment. Ammonium chloride was used as the nitrogen source, potassium dihydrogen phosphate as the phosphorus source, and NaHCO3 solution was added to the influent to maintain the pH within the range of 7.0–8.0. Simultaneously, trace elements such as calcium required for microbial growth were supplemented.2+ Mg 2+ Fe 2+ The composition of the artificially simulated wastewater is shown in Table 1:

[0060] In this Example 2, a 5 mg / L ciprofloxacin solution and artificially simulated wastewater were added to the main body 1 of the photosynthetic reactor at a volume ratio of 1:9. At the same time, g-C3N4 photocatalyst was added along with the wastewater. The photocatalyst was added to the main body 1 of the photosynthetic reactor at a concentration of 0.2 g / L through a chemical addition device.

[0061] The ammonia nitrogen content before and after wastewater treatment was determined according to the national standard "Determination of Ammonia Nitrogen in Water - Nessler's Reagent Spectrophotometric Method" (HJ535-2009); the nitrate nitrogen content before and after wastewater treatment was determined according to the national standard "Determination of Nitrite Nitrogen in Water - Spectrophotometric Method" (GB7493-87). The average concentrations of effluent from the autotrophic photocatalytic-algae symbiotic integrated treatment device for antibiotic-containing wastewater before and after the addition of g-C3N4 nanomaterials are shown in Table 2.

[0062]

[0063] Experimental results show that after long-term stable operation, the effluent quality reaches a stable level. After adding g-C3N4, the treatment effect of the self-trophic photocatalytic-bacterial-algae symbiotic integrated treatment device for ciprofloxacin-containing wastewater is significantly improved, with the effluent CIP removal rate reaching over 80%.

[0064] Firstly, under illumination, the photocatalytic properties of the photocatalyst enable it to efficiently capture light energy and generate photogenerated electrons to reduce CO2. Therefore, adding the photocatalyst material to water can act as a light-capturing agent to assist bacteria in wastewater treatment, thus overcoming the difficulty of light capture by bacteria and algae. Simultaneously, under visible light excitation, the photocatalyst supported on the carrier surface generates a large number of free radicals, which then attack the reaction sites in the antibiotic molecule structure. This leads to the formation of intermediate products, which are then used as a carbon source for further decomposition by the microorganisms within the carrier. This demonstrates the potential for treating antibiotic pollution in livestock farming and provides a new solution to this problem.

[0065] g-C3N4 nanomaterials possess a moderate bandgap, enabling resonance with the visible light spectrum. Their layered lattice structure facilitates rapid separation of photogenerated carriers. Compared to metal-based catalysts, the bioinertness of carbon nitride materials ensures the integrity of microbial communities. Experiments revealed that the catalyst's surface potential induces changes in the secretion pattern of extracellular polymers in algae, triggering self-assembly behavior of microalgae in the aqueous environment. Stable biofilm structures can be formed around bacterial flocs without external loading, simplifying the problem of biofilm detachment in traditional processes.

[0066] During the treatment process, a suitable ratio of microalgae to bacteria in the symbiotic system promotes better symbiosis between microalgae and bacteria. Oxygen produced by microalgae photosynthesis is utilized by bacteria, while carbon dioxide produced by bacteria is absorbed by microalgae for photosynthesis. In the algae-microbe symbiotic biofilm system, the microbial community and photosynthetic algae form a synergistic composite structure. The biofilm matrix, with its stable three-dimensional structure, possesses good environmental resistance and high mass transfer efficiency, maintaining a stable dominant bacterial community distribution and exhibiting strong pollutant tolerance during treatment. Algae form a dense covering layer on the membrane surface, improving interfacial properties through secreted hydrophilic and hydrophobic substances, promoting solid-liquid separation efficiency in the system, and simultaneously enhancing the capture and conversion of nutrients such as nitrogen and phosphorus.

[0067] In this symbiotic system, algae continuously release dissolved oxygen through photosynthesis, replacing the need for mechanical aeration in traditional processes and significantly reducing the system's energy consumption. Furthermore, by absorbing carbon-containing substances produced by microbial metabolism, algae achieve internal carbon recycling while reducing greenhouse gas emissions, thus forming a low-carbon treatment model. This metabolic complementarity mechanism not only optimizes the exchange of matter and energy between bacteria and algae but also enhances system stability through the carrier role of the biofilm, providing technical support for the simultaneous treatment of pollutants and resource recovery. This integrated design effectively balances treatment efficiency and sustainability, demonstrating good development potential in practical applications.

Claims

1. An integrated wastewater treatment device for autotrophic photocatalysis and algae symbiosis, characterized in that, include: The main body of the photosynthetic reactor is a light-transmitting container. The main body of the photosynthetic reactor is provided with an inlet, an outlet and at least one sampling port, and each sampling port is provided with a valve. A symbiotic biofilm component of bacteria and algae is disposed inside the main body of the photosynthetic reactor and includes a bracket and a porous carrier suspended on the bracket; A light source assembly is disposed inside the main body of the photosynthetic reactor and is used to provide illumination; the light source assembly includes an LED light source and a sealed light-transmitting carrier disposed outside the LED light source, and the sealed light-transmitting carrier is detachably connected to the main body of the photosynthetic reactor. The drug dosing device is connected to the inlet of the photosynthetic reactor body or the interior of the photosynthetic reactor body via a pipeline; The PLC control system is connected to the LED light source and the drug dosing device.

2. The autotrophic photocatalytic-algae symbiotic integrated wastewater treatment device according to claim 1, characterized in that, The photosynthetic reactor body is equipped with a heating rod and a temperature probe; both the temperature probe and the heating rod are connected to the PLC control system. Or / and a pH probe is installed inside the main body of the photosynthetic reactor, and the pH probe is connected to the PLC control system; Or / and a DO probe is installed inside the main body of the photosynthetic reactor, and the DO probe is connected to the PLC control system.

3. The autotrophic photocatalytic-algae symbiotic integrated wastewater treatment device according to claim 1, characterized in that, The water inlet is located at the bottom of the photosynthetic reactor body, and the drain outlet is located in the middle of the photosynthetic reactor body; multiple sampling ports are spaced apart along the height direction of the photosynthetic reactor body. Or / and the main body of the photosynthetic reactor is a light-transmitting cylindrical structure, made of transparent acrylic material or transparent glass; Or / and the filling rate of the porous carrier is 15% to 25% of the effective volume of the main body of the photosynthetic reactor; Or / and the hanging frame is provided in two sets at intervals along the height direction of the photosynthetic reactor body, and multiple sets of hanging lines are provided between the two sets of hanging frames, and multiple porous carriers are provided on the hanging lines; Or / and the porous carrier is a polyurethane sponge carrier.

4. The autotrophic photocatalytic-algae symbiotic integrated wastewater treatment device according to claim 3, characterized in that, The hanging bracket is made of stainless steel. Or / and the hanging wire is a polyethylene wire; Or / and the polyurethane foam carrier is tetragonal in shape.

5. The autotrophic photocatalytic-algae symbiotic integrated wastewater treatment device according to claim 1, characterized in that, The LED light source is a variable LED light source with an adjustable illuminance in the range of 3000~8000 lux. The PLC control system is configured to control the LED light source to operate periodically according to a preset light / dark time ratio, wherein the light / dark time ratio is 10h:14h to 14h:10h. Or / and the main wavelength band of the emission spectrum of the LED light source includes blue light of 400-500nm and red light of 600-700nm.

6. The autotrophic photocatalytic-algae symbiotic integrated wastewater treatment device according to claim 1, characterized in that, The drug dosing device is used to add a photocatalyst into the main body of the photosynthetic reactor. The photocatalyst is g-C3N4 nanomaterial, and the dosing concentration is 0.1~0.5g / L.

7. The autotrophic photocatalytic-algae symbiotic integrated wastewater treatment device according to claim 1, characterized in that, The device also includes a solid-liquid separation device connected to the drain outlet of the main body of the photosynthetic reactor.

8. The autotrophic photocatalytic-algae symbiotic integrated wastewater treatment device according to claim 1, characterized in that, The inlet is connected to external wastewater via an inlet pipe, on which a peristaltic pump and a rotor flow meter are installed. The outlet is connected to a drain pipe, on which a timer and a drain solenoid valve are installed. The peristaltic pump, rotor flow meter, timer, and drain solenoid valve are all connected to a PLC system.

9. A wastewater treatment method, characterized in that, The apparatus according to any one of claims 1-8 comprises the following steps: S1. System startup and biofilm formation: Autotrophic sludge and Chlorella in the logarithmic growth phase are inoculated into the main body of the photosynthetic reactor, and a stable bacterial-algal symbiotic biofilm is formed on the porous biological carrier. S2. Wastewater treatment: Wastewater is pumped into the main body of the photosynthetic reactor, and g-C3N4 photocatalyst at a concentration of 0.1~0.3g / L is added to the main body of the photosynthetic reactor through the reagent dosing device. S3. Sequential Batch Operation: The sequential batch operation mode of water intake, light reaction, sedimentation, and drainage is adopted, with a single cycle of 24 hours. During the light reaction stage, the LED light source is turned on, and the light intensity is controlled to maintain the dissolved oxygen concentration of the system at 1~3mg / L. During the sedimentation and drainage stages, the light source is turned off. S4. Continuous operation: Repeat steps S2 to S3 to achieve continuous wastewater treatment.

10. The wastewater treatment method according to claim 9, characterized in that, The wastewater contains antibiotics. In step S1, the inoculation amount of the fully autotrophic sludge is 3~7 g / L, and the inoculation amount of Chlorella is 0.2~1.0 g / L.

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