A treatment process and system for high-oil and high-phosphorus wastewater

Abstract

The application discloses a treatment process of high-oil-stain and high-phosphorus wastewater, and particularly comprises the following steps: treating the wastewater by using microbial balls; performing photocatalytic treatment on the wastewater by using a photocatalytic membrane; and adjusting the dissolved oxygen content of the wastewater to 3-4 mg / L; wherein the microbial balls contain bacillus tropicus and chlorella vulgaris bacteria. The application further discloses a treatment system of high-oil-stain and high-phosphorus wastewater using the treatment process. The treatment process and system of high-oil-stain and high-phosphorus wastewater can effectively degrade total phosphorus and organic pollutants, especially oil pollutants, in the wastewater, and effectively prevent the pollution and blockage of the composite photocatalytic membrane by the oil stains.

Description

Technical Field

[0001] This invention belongs to the field of industrial wastewater treatment, and more specifically, relates to a treatment process and system for high-oil and high-phosphorus wastewater. Background Technology

[0002] Photocatalysis is a novel advanced oxidation technology that uses semiconductor materials as catalysts to directly convert light energy into chemical energy. Under ultraviolet or visible light irradiation, photocatalysts can generate highly oxidizing free radicals, which can decompose most organic substances harmful to humans and the environment, as well as some inorganic substances, ultimately producing small inorganic molecules such as H2O and CO2. This avoids resource waste and secondary pollution, and therefore has received widespread attention both domestically and internationally. Among various semiconductor photocatalysts, TiO2 photocatalysts are widely used in water treatment due to their advantages such as low cost, non-toxicity, strong photochemical stability, and lack of secondary pollution.

[0003] Patent CN105854899B discloses "a Bi2S3 / TiO2 composite visible light catalyst and its preparation method," which combines TiO2 with the narrow bandgap semiconductor Bi2S3 to achieve visible light photocatalytic activity. Bi2S3 is a layered semiconductor with a bandgap energy of only 1.3 eV, which can be excited by visible light, and photogenerated electrons can be directly injected into the conduction band of TiO2, giving it potential visible light photocatalytic activity.

[0004] Automotive painting wastewater is primarily generated during the production process in automotive painting workshops. It contains a wide variety of pollutants in large quantities, including significant amounts of oil and total phosphorus. When treating this wastewater using membranes loaded with the aforementioned composite photocatalyst, oil easily adheres to the membrane surface, clogging the pores and causing membrane fouling. This leads to decreased water flux, increased operating pressure, reduced membrane lifespan, increased energy consumption, and decreased treatment efficiency. Regular cleaning of the composite photocatalyst membrane is also detrimental to the continuous operation of wastewater treatment. Furthermore, the high total phosphorus content in automotive painting wastewater necessitates a separate degradation treatment step in the wastewater treatment process, further reducing treatment efficiency and increasing costs. Summary of the Invention

[0005] 1. The problem to be solved

[0006] To address the problem of oil contamination and clogging of composite photocatalytic membranes in existing automotive painting wastewater treatment processes, this invention provides a treatment process for high-oil, high-phosphorus wastewater. The purpose of this process is to achieve highly efficient degradation of oil contaminants in wastewater by organically combining microbial balls, micro / nano bubble generators, visible light sources, and composite photocatalytic membranes. This significantly slows down the contamination process of the composite photocatalytic membrane, effectively increases its flux, and reduces the frequency of chemical cleaning. Simultaneously, this invention's process can also degrade total phosphorus, simplifying existing automotive painting wastewater treatment processes and eliminating the need for a separate total phosphorus degradation step.

[0007] In addition to the above objectives, the present invention also provides a treatment system for high-oil and high-phosphorus wastewater, such as automotive painting wastewater.

[0008] 2. Technical Solution

[0009] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0010] This invention provides a treatment process for wastewater with high oil and high phosphorus content, comprising the following steps:

[0011] Wastewater is treated using microbial balls;

[0012] Photocatalytic treatment of wastewater using photocatalytic membranes;

[0013] Adjust the dissolved oxygen content of the wastewater to 3-4 mg / L;

[0014] The microbial balls contain tropical Bacillus and common Chlorella.

[0015] In this invention, *Bacillus tropicalis* can effectively degrade organic pollutants in an aerobic environment, especially oily pollutants. Based on this, this invention proposes a symbiotic system of *Bacillus tropicalis* and *Chlorella vulgaris* to design a microbial ball for treating wastewater with high oil and phosphorus content. In the symbiotic system, the carbon dioxide produced by *Bacillus tropicalis* during its metabolism of degrading organic pollutants is utilized by *Chlorella vulgaris*. *Chlorella vulgaris*, in turn, utilizes light and carbon dioxide to degrade phosphorus in the wastewater, synthesizing organic matter and providing nutrients to *Bacillus tropicalis*. The two organisms mutually benefit each other, jointly treating oil and phosphorus pollutants, for example, in automotive painting wastewater. Simultaneously, a micro / nano bubble generator provides an aerobic environment for the microbial ball; a visible light source provides illumination for the microbial ball and the photocatalytic membrane.

[0016] The specific technical solution is as follows:

[0017] [A treatment process for wastewater with high oil and high phosphorus content]

[0018] The first aspect of this invention provides a treatment process for wastewater with high oil and high phosphorus content, the treatment process specifically including the following steps:

[0019] Microbial ball preparation steps:

[0020] Preparation of mycelial mud A: Bacillus tropicalis was cultured to the logarithmic growth phase, and centrifuged to obtain wet mycelial mud, which is denoted as mycelial mud A;

[0021] Preparation of microbial sludge B: Chlorella vulgaris was cultured to the logarithmic growth phase, and centrifuged to obtain wet microbial sludge, which was denoted as microbial sludge B;

[0022] Preparation of mixed mycelium sludge C: Mix mycelium sludge A and mycelium sludge B evenly to form mixed mycelium sludge C;

[0023] Immobilization and embedding: The mixed bacterial sludge C is immobilized and embedded to prepare microbial balls.

[0024] Membrane treatment reactor construction steps: The visible light source, photocatalytic membrane, and micro / nano bubble generator are organically combined and set up in the membrane treatment reactor;

[0025] Microbial ball inoculation step: The microbial balls are inoculated into the membrane treatment reactor;

[0026] Wastewater treatment steps: High-oil and high-phosphorus wastewater is continuously and evenly fed into the membrane treatment reactor from the bottom, and the water is pumped out using an outlet pump to achieve photocatalytic membrane filtration.

[0027] As a preferred embodiment of any aspect of the present invention, the method for culturing *Bacillus tropicalis* involves inoculating *Bacillus tropicalis* into LB liquid medium, culturing it at 30–35°C until the logarithmic growth phase, and centrifuging at 6000–10000 rpm to obtain wet bacterial sludge, denoted as bacterial sludge A. The content of *Bacillus tropicalis* in bacterial sludge A is 2 × 10⁻⁶. 10 ~8×10 10 CFU / mL.

[0028] As a preferred embodiment of any aspect of the present invention, the method for culturing *Chlorella vulgaris* is as follows: *Chlorella vulgaris* is inoculated into a blue-green algae culture medium (BG-11 culture medium), the light-dark ratio is controlled at 12h:12h to 14h:12h, the light intensity is 5000 to 7000 lx, and the culture is carried out at 25 to 28°C until the logarithmic growth phase. The resulting wet bacterial sludge is obtained by centrifugation at 6000 to 10000 rpm and is denoted as bacterial sludge B. The content of *Chlorella vulgaris* in bacterial sludge B is 1 × 10⁻⁶. 9 ~5×10 9 CFU / mL.

[0029] As a preferred embodiment of any of the first aspects of the present invention, the method for preparing the mixed bacterial mud C is to fully mix bacterial mud A and bacterial mud B at a mass ratio of 1:4 to 1:5 under conditions of 2 to 6°C to obtain mixed bacterial mud C.

[0030] As a preferred embodiment of any of the first aspects of the present invention, the method for immobilizing and embedding the mixed bacterial sludge C includes:

[0031] The mixed bacterial sludge C is inoculated into a 2-5 wt% sodium alginate solution, with an inoculation amount of 20-30%, and mixed evenly to obtain a mixed solution; the sodium alginate solution is preferably a 3 wt% sodium alginate solution;

[0032] The mixture is added dropwise to a 3-10 wt% calcium chloride solution and allowed to stand until it solidifies into spheres; the calcium chloride solution is preferably a 5 wt% calcium chloride solution.

[0033] The calcium chloride solution containing the small spheres was refrigerated at 4°C and allowed to stand for 10–15 hours.

[0034] Microbial balls were obtained by screening small balls with a diameter of 4-6 mm using a sieve with a customized aperture, rinsing the surface of the balls with sterile physiological saline to remove residual liquid, and then draining them.

[0035] The immobilization and embedding method in this invention uses a sodium alginate-calcium chloride system. The polymerized microbial spheres are crystal clear, free of turbidity and sediment, and have good light transmittance, making them more suitable for the common Chlorella species that require light in this invention. Furthermore, this immobilization and embedding method does not use boric acid, a common component in conventional immobilization processes, resulting in less damage to the microorganisms, effectively improving the survival rate of the embedded microorganisms, reducing the use of boric acid, and lowering the preparation cost of the microbial spheres.

[0036] This invention immobilizes and embeds a symbiotic system (Bacillus tropicalis and Chlorella vulgaris) together, creating a tight bond that facilitates material transfer and improves degradation efficiency. Simultaneously, the microbial balls possess higher mechanical strength, preventing them from breaking down during continuous aeration and water intake in the membrane treatment reactor, thus preventing the loss of functional microorganisms. The high mechanical strength of the microbial balls may be related to certain substances secreted on the surface of Chlorella vulgaris.

[0037] As a preferred embodiment of any of the first aspects of the present invention, the membrane treatment reactor is organically combined with a visible light source, a photocatalytic membrane, and a micro / nano bubble generator:

[0038] The height-to-diameter ratio of the membrane treatment reactor is 3:1 to 4:1;

[0039] The visible light source is uniformly arranged inside the membrane treatment reactor, and the intensity of the visible light source is controlled at 5000–7000 lx / m. 3 The controller alternately controls the light source to turn on and off, controlling the light-dark time ratio to be 12h:12h to 14h:12h.

[0040] The micro-nano bubble generator introduces micro-nano bubbles from the bottom of the membrane treatment reactor, thereby controlling the dissolved oxygen level in the membrane treatment reactor to be 3-4 mg / L.

[0041] The photocatalytic membrane is positioned above half the height of the membrane treatment reactor;

[0042] The amount of the photocatalytic membrane used is 25-30 cm. 2 / L;

[0043] The photocatalyst loading in the photocatalytic membrane is 5–8 mg / cm³. 2 .

[0044] More preferably, the photocatalytic membrane is a composite photocatalytic membrane, and the photocatalyst is a composite photocatalyst.

[0045] Microbial balls with a particle size of 4–6 mm are mainly distributed in the area below 1 / 2 height of the membrane treatment reactor in a continuously aerated and influent membrane treatment reactor, which is distinct from the photocatalytic membrane module area. Moreover, the microbial balls are fully expanded and suspended in this area, resulting in high degradation efficiency of oil and total phosphorus.

[0046] If the particle size of the microbial balls is too small, they will enter the photocatalytic membrane module area under continuous aeration and water intake. The hydroxyl radicals generated on the surface of the photocatalytic membrane will affect the growth of microorganisms in the microbial balls. The microbial balls will also block the light required by the photocatalytic membrane. At the same time, the consumption of hydroxyl radicals by the microbial balls will also affect the self-cleaning effect of hydroxyl radicals on the photocatalytic membrane.

[0047] If the particle size of the microbial balls is too large, it will lead to an uneven distribution of a large number of microbial balls, which will accumulate at the bottom of the membrane treatment reactor. The light will be blocked by each other, which will affect the growth and degradation function of ordinary Chlorella in the microbial balls.

[0048] Microbial balls exhibit better growth and degradation efficiency in the environment provided by the membrane treatment reactor.

[0049] Further optimization yields micro- and nano-bubbles with a particle size of 40–80 μm.

[0050] When micro- and nano-bubbles with a particle size of 40–80 μm are formed, the charge density of the double layer increases rapidly. When the bubble bursts at the top, the energy stored in the high concentration of positive and negative ions at the gas-liquid interface is released with the dramatic change of the disappearance of the gas-liquid interface. The generated hydroxyl radicals can remove organic pollutants and also clean the composite photocatalytic membrane.

[0051] As a preferred embodiment of any of the first aspects of the present invention, the amount of microbial balls inoculated into the membrane treatment reactor is 25-35%.

[0052] Within the inoculation range mentioned above, microbial balls have a higher utilization rate of dissolved oxygen and light in water, and a higher degradation efficiency for oil and total phosphorus.

[0053] As a preferred embodiment of any of the first aspects of the present invention, wastewater is continuously and uniformly introduced in the wastewater treatment step, the hydraulic retention time is controlled to be 16 to 24 hours, the pH is controlled to be 7.0 to 7.5 and the operating temperature is controlled to be 25 to 30°C during the operation of the membrane treatment reactor.

[0054] Continuous and uniform water inflow eliminates the need for a wastewater equalization tank, saving floor space. Continuous water inflow keeps the microbial balls suspended, ensuring that the common chlorella within the balls has ample contact with the light source, guaranteeing its normal growth. The suspended microbial balls also ensure sufficient contact with the wastewater, improving treatment efficiency. Furthermore, the microbial balls exhibit higher activity and better degradation of organic matter and total phosphorus in an environment with a pH of 7.0–7.5 and a temperature of 25–30°C.

[0055] [A treatment system for wastewater with high oil and high phosphorus content]

[0056] The second aspect of the present invention provides a treatment system for implementing the high oil and high phosphorus wastewater treatment process provided in the first aspect of the present invention, comprising, in sequence, an influent system, a membrane treatment reactor system and an effluent system;

[0057] The membrane treatment reactor system includes a membrane treatment reactor, a visible light source, a photocatalytic membrane, a micro / nano bubble generator, and microbial balls in a high-oil, high-phosphorus wastewater treatment process provided in the first aspect of the present invention.

[0058] The water inlet system is located at the bottom of the membrane treatment reactor;

[0059] The height-to-diameter ratio of the membrane treatment reactor is 3:1 to 4:1;

[0060] The visible light source is uniformly arranged inside the membrane treatment reactor, and the intensity of the visible light source is controlled at 5000–7000 lx / m. 3 The controller alternately controls the light source to turn on and off, controlling the light-dark time ratio to be 12h:12h to 14h:12h.

[0061] The micro-nano bubble generator introduces micro-nano bubbles from the bottom of the membrane treatment reactor, thereby controlling the dissolved oxygen level in the membrane treatment reactor to be 3-4 mg / L; further, the particle size of the micro-nano bubbles is 40-80 μm;

[0062] The photocatalytic membrane is positioned above half the height of the membrane treatment reactor;

[0063] The photocatalytic membrane is connected to a water pump, and the water pump is connected to the water outlet system.

[0064] 3. Beneficial effects

[0065] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0066] (1) This invention utilizes the synergistic effect of microbial balls, micro-nano bubble generators, visible light sources and photocatalytic membranes to jointly degrade total phosphorus and organic pollutants in wastewater, especially oil pollutants. It effectively prevents oil from accumulating on the surface of the photocatalytic membrane and clogging the membrane pores. At the same time, it can also clean the oil that has already adhered to the photocatalytic membrane, slow down the rate of flux decline of the photocatalytic membrane, extend the service life of the photocatalytic membrane, and reduce the frequency of chemical cleaning of the photocatalytic membrane, thereby reducing the cost of wastewater treatment.

[0067] (2) The microbial balls in this invention utilize a symbiotic system to efficiently remove phosphorus while degrading organic pollutants. This eliminates the need for phosphorus removal agents and also saves the separate phosphorus degradation process, further reducing the cost of wastewater treatment.

[0068] (3) The process and system structure of the present invention are simple and the design is reasonable, which is conducive to the transformation of existing technologies. Attached Figure Description

[0069] Figure 1 This is a schematic diagram of a treatment process for high-oil and high-phosphorus wastewater according to the present invention;

[0070] In the diagram: 1. Membrane treatment reactor; 2. Microbial balls; 3. Composite photocatalytic membrane; 4. Visible light source; 5. Water pump; 6. Micro / nano bubble generator. Detailed Implementation

[0071] It should be noted that when a component is referred to as being "mounted" on another component, it can be directly on the other component or the two components can be integrated as one unit; when a component is referred to as being "connected" to another component, it can be directly connected to the other component or the two components can be integrated as one unit. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity of description and are not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0072] 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 invention pertains; the term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0073] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0074] As used herein, the term “about” is used to provide for the flexibility and imprecision associated with a given term, measure, or value. Those skilled in the art can readily determine the degree of flexibility for a particular variable.

[0075] As used herein, “adjacent” means that two structures or elements are close to each other. Specifically, elements identified as “adjacent” may be adjacent or connected. Such elements may also be close to or near each other without necessarily touching. In some cases, the precision of proximity may depend on the specific context.

[0076] As used herein, the term “at least one of…” is intended to be synonymous with “one or more of…”. For example, “at least one of A, B, and C” explicitly includes only A, only B, only C, and combinations thereof.

[0077] Concentration, amount, and other numerical data may be presented in range format herein. It should be understood that such range format is used solely for convenience and brevity and should be flexibly interpreted to include not only the values ​​explicitly stated as the limits of the range, but also all individual values ​​or subranges encompassed within the range, as if each value and subrange were explicitly stated. For example, a range of values ​​from about 1 to about 4.5 should be interpreted to include not only the explicitly stated limits of 1 to 4.5, but also individual numbers (such as 2, 3, 4) and subranges (such as 1 to 3, 2 to 4, etc.). The same principle applies to ranges that describe only a single value, such as “less than about 4.5,” which should be interpreted to include all the aforementioned values ​​and ranges. Furthermore, this interpretation should apply regardless of the breadth of the range or characteristic described.

[0078] Any step described in any method or process claim (e.g., steps S1, S2, S3... or steps (1), (2), (3)... or steps 1), 2), 3)...) may be performed in any order, and is not limited to the order set forth in the claims.

[0079] The limitation of method + function or step + function is used only if all of the following conditions are met in a particular claim: a) it expressly states "a method for..." or "a step for..."; b) it expressly states the corresponding function. The structures, materials, or actions supporting the method + function are expressly described in the description herein. Therefore, the scope of the invention should be determined solely by the appended claims and their legal equivalents, and not by the description and examples given herein.

[0080] The present invention will be further described below with reference to specific embodiments.

[0081] Process materials:

[0082] LB liquid culture medium was purchased from Jiangsu Kaiji Biotechnology Co., Ltd., BG-11 culture medium was purchased from Sigma-Aldrich, sodium alginate and calcium chloride were purchased from Adamas, and sterile physiological saline was purchased from Haibo Biotechnology Co., Ltd.

[0083] Tropical Bacillus and common Chlorella can be purchased from Wuhan Gray Algae Biotechnology Co., Ltd.

[0084] Pre-preparation:

[0085] Activated sludge: Activated sludge was obtained by cultivating and acclimatizing the sludge in the automotive painting wastewater treatment process using conventional acclimatization methods;

[0086] 3wt% sodium alginate solution: Dissolve sodium alginate in the corresponding sterile physiological saline at a ratio of 3wt% to obtain a 3wt% sodium alginate solution;

[0087] 5wt% calcium chloride solution: Dissolve calcium chloride in the corresponding sterile physiological saline at a ratio of 5wt% to obtain a 5wt% calcium chloride solution.

[0088] The composite photocatalytic membrane was prepared by the following method:

[0089] (1) Weigh 1.31g of bismuth nitrate pentahydrate, dissolve it in 5mL of ethylene glycol, and stir magnetically for 20min to obtain clear solution A;

[0090] (2) Weigh 1.56g of sodium sulfide and dissolve it in deionized water. Stir magnetically to obtain a clear solution B.

[0091] (3) Under vigorous stirring, solution B is added dropwise to solution A to obtain a black suspension C;

[0092] (4) Add 0.64g of urea to solution C, stir for 30min, transfer it to a reaction vessel, hydrothermally heat at 120℃ for 12h, cool naturally to room temperature, filter, and wash the solid several times with deionized water and anhydrous ethanol respectively, and dry at 80℃ for 4h to obtain solid Bi2S3.

[0093] (5) Measure 4 mL of tetrabutyl titanate, mix it with 10 mL of anhydrous ethanol, sonicate for 30 min, and then stir magnetically for 30 min to obtain a light yellow transparent sol D;

[0094] (6) The solid Bi2S3 obtained in step (4) was added to sol D at a molar ratio of 1:5 with titanium dioxide, ultrasonically dispersed for 30 min, and then stirred for 30 min; then the suspension was transferred to a reaction vessel and hydrothermally synthesized at 180°C for 12 h; after naturally cooling to room temperature, it was filtered and washed several times with anhydrous ethanol, dried at 100°C for 3 h, and then calcined in a muffle furnace at 450°C for 4.5 h to obtain the Bi2S3 / TiO2 composite photocatalyst.

[0095] (7) Prepare a sufficient amount of composite photocatalyst according to the above method, and load the composite photocatalyst onto a filter membrane to obtain a composite photocatalytic membrane. The composite photocatalyst loading of the composite photocatalytic membrane is 6 mg / cm³. 2 .

[0096] Example 1

[0097] Preparation steps of microbial balls 2:

[0098] Preparation of mycotic sludge A: Bacillus tropicalis was inoculated into LB liquid medium and cultured at 30°C until the logarithmic growth phase. The culture was then transferred to a centrifuge and centrifuged at 8000 rpm to obtain wet mycotic sludge, denoted as mycotic sludge A. The content of Bacillus tropicalis in mycotic sludge A was 5 × 10⁻⁶. 10 CFU / mL.

[0099] Preparation of Microbial Sludge B: Common Chlorella was inoculated onto a blue-green algae culture medium (BG-11 broth), with a light-dark ratio of 12h:12h. Alternating irradiation was performed under a light intensity of 5000 lx at 25℃ until the logarithmic growth phase. The culture was then transferred to a centrifuge and centrifuged at 8000 rpm to obtain wet microbial sludge, denoted as Microbial Sludge B. The content of Common Chlorella bacteria in Microbial Sludge B was 2 × 10⁻⁶. 9 CFU / mL.

[0100] Preparation of mixed microbial sludge C: Microbial sludge A and microbial sludge B are thoroughly mixed at a mass ratio of 1:4 at 4℃ to form mixed microbial sludge C.

[0101] Immobilization and embedding: Mixed bacterial sludge C was inoculated into a 3wt% sodium alginate solution at an inoculation rate of 20%, meaning the volume of inoculated mixed bacterial sludge C accounted for 20% of the volume of the mixed liquid after inoculation. The mixture was thoroughly stirred to form a homogeneous solution. The solution was then added dropwise to a 5wt% calcium chloride solution using a syringe, with the volume of the added solution not exceeding 60% of the volume of the calcium chloride solution. After solidification to form spheres, the calcium chloride solution containing the spheres was transferred to a 4℃ refrigerator and allowed to stand for 10 hours. After removal, spheres with a diameter of 4-6 mm were screened using custom-made sieves with apertures of 4 mm and 6 mm, respectively. The surface residual liquid was rinsed with sterile physiological saline, and after draining, microbial spheres 2 were obtained.

[0102] Construction steps of membrane treatment reactor 1:

[0103] like Figure 1 As shown, a membrane treatment reactor 1 is constructed, specifically including: the height-to-diameter ratio of the membrane treatment reactor 1 is set to 3:1; visible light sources 4 are uniformly distributed inside the membrane treatment reactor 1, and the intensity of the visible light sources 4 inside the membrane treatment reactor 1 is controlled to 6000 lx / m. 3 The system maintains a light-to-dark time ratio of 12h:12h using a controller, alternately controlling the on / off state of the visible light source 4. Micro-nano bubbles with a particle size of 40–80 μm, generated by a micro-nano bubble generator 6, are introduced into the bottom of the membrane treatment reactor 1 to control the dissolved oxygen level in the reactor to 3 mg / L. A composite photocatalytic membrane 3 assembly is fixedly installed in the upper part (above halfway) of the membrane treatment reactor 1. The composite photocatalytic membrane 3 is 28 cm³. 2 / L, specifically, 28cm per 1L of wastewater. 2 3. Composite photocatalytic membrane with area 3.

[0104] Microbial ball 2 inoculation steps:

[0105] Microbial balls 2 are inoculated into membrane treatment reactor 1 at an inoculation rate of 25%, meaning the volume of inoculated microbial balls 2 is 25% of the effective volume of membrane treatment reactor 1. The effective volume of membrane treatment reactor 1 is the volume of membrane treatment reactor 1 after deducting the volume of various reactor components (including the composite photocatalytic membrane 3 component).

[0106] Wastewater treatment steps:

[0107] The automotive painting wastewater is continuously and evenly introduced from the bottom of the membrane treatment reactor 1, with the hydraulic retention time controlled at 16 hours, the pH inside the membrane treatment reactor 1 controlled at 7.0, and the operating temperature controlled at 25°C. The water is pumped out using an external effluent pump 5 to achieve membrane filtration effluent.

[0108] The transmembrane pressure difference of the composite photocatalytic membrane 3 reflects the degree of fouling; a larger transmembrane pressure difference indicates a higher degree of fouling and blockage. After 30 days of continuous reactor operation, the transmembrane pressure difference was 14.6 kPa. The changes in water quality before and after wastewater treatment were measured as follows:

[0109] Testing items Before processing After processing COD (mg / L) 1650 97 Total phosphorus (mg / L) 38 4 Petroleum products (mg / L) 62 5.6

[0110] Example 2

[0111] Preparation steps of microbial balls 2:

[0112] Preparation of mycotic sludge A: Bacillus tropicalis was inoculated into LB liquid medium and cultured at 30°C until the logarithmic growth phase. The culture was then transferred to a centrifuge and centrifuged at 8000 rpm to obtain wet mycotic sludge, denoted as mycotic sludge A. The content of Bacillus tropicalis in mycotic sludge A was 5 × 10⁻⁶. 10 CFU / mL.

[0113] Preparation of Microbial Sludge B: Common Chlorella was inoculated onto a blue-green algae culture medium (BG-11 broth), with a light-dark ratio of 12h:12h. Alternating irradiation was performed under a light intensity of 5000 lx at 25℃ until the logarithmic growth phase. The culture was then transferred to a centrifuge and centrifuged at 8000 rpm to obtain wet microbial sludge, denoted as Microbial Sludge B. The content of Common Chlorella bacteria in Microbial Sludge B was 2 × 10⁻⁶. 9 CFU / mL.

[0114] Preparation of mixed microbial sludge C: Mix microbial sludge A and microbial sludge B thoroughly at a mass ratio of 1:5 at 4℃ to form mixed microbial sludge C.

[0115] Immobilization and embedding: Mixed bacterial sludge C was inoculated into a 3 wt% sodium alginate solution, with an inoculation amount of 30%, meaning the volume of inoculated mixed bacterial sludge C accounted for 30% of the volume of the mixed liquid after inoculation. The mixture was thoroughly stirred to form a homogeneous solution. The solution was then added dropwise to a 5 wt% calcium chloride solution using a syringe, with the volume of the added solution not exceeding 60% of the volume of the calcium chloride solution. After solidification to form spheres, the calcium chloride solution containing the spheres was transferred to a 4°C refrigerator and allowed to stand for 15 hours. After removal, spheres with a diameter of 4–6 mm were screened using custom-made sieves with apertures of 4 mm and 6 mm, respectively. The surface residual liquid was rinsed with sterile physiological saline, and after draining, microbial spheres 2 were obtained.

[0116] Construction steps of membrane treatment reactor 1:

[0117] like Figure 1 As shown, a membrane treatment reactor 1 is constructed, specifically including: the height-to-diameter ratio of the membrane treatment reactor 1 is set to 4:1; visible light sources 4 are uniformly distributed inside the membrane treatment reactor 1, and the intensity of the visible light sources 4 inside the membrane treatment reactor 1 is controlled to 6000 lx / m. 3 The system maintains a light-dark time ratio of 12h:12h using a controller, alternately controlling the on / off state of the visible light source 4. Micro-nano bubbles with a particle size of 40–80 μm, generated by a micro-nano bubble generator 6, are introduced into the bottom of the membrane treatment reactor 1 to control the dissolved oxygen level in the reactor to 4 mg / L. A composite photocatalytic membrane 3 assembly is fixedly installed in the upper part (above halfway) of the membrane treatment reactor 1. The composite photocatalytic membrane 3 is 28 cm³. 2 / L, specifically, 28cm per 1L of wastewater. 2 3. Composite photocatalytic membrane with area 3.

[0118] Microbial ball 2 inoculation steps:

[0119] Microbial balls 2 are inoculated into membrane treatment reactor 1 at an inoculation rate of 35%, meaning the volume of inoculated microbial balls 2 is 35% of the effective volume of membrane treatment reactor 1. The effective volume of membrane treatment reactor 1 is the volume of membrane treatment reactor 1 after deducting the volume of various reactor components (including the composite photocatalytic membrane 3 component).

[0120] Wastewater treatment steps:

[0121] The automotive painting wastewater is continuously and evenly introduced from the bottom of the membrane treatment reactor 1, with the hydraulic retention time controlled at 24 hours, the pH inside the membrane treatment reactor 1 controlled at 7.5, and the operating temperature controlled at 30°C. The water is pumped out using an external effluent pump 5 to achieve membrane filtration effluent.

[0122] After the reactor operated continuously for 30 days, the transmembrane pressure difference was 12.9 kPa. The changes in water quality before and after wastewater treatment were measured as follows:

[0123] Testing items Before processing After processing COD (mg / L) 1650 85 Total phosphorus (mg / L) 38 3.2 Petroleum products (mg / L) 62 3.9

[0124] The wastewater purification effect in Example 2 is better than that in Example 1.

[0125] Example 3

[0126] Preparation steps of microbial balls 2:

[0127] Preparation of mycotic sludge A: *Bacillus tropicalis* was inoculated onto LB liquid medium and cultured at 32°C until the logarithmic growth phase. The culture was then transferred to a centrifuge and centrifuged at 8000 rpm to obtain wet mycotic sludge, denoted as mycotic sludge A. The *Bacillus tropicalis* content in mycotic sludge A was 7 × 10⁻⁶. 10 CFU / mL.

[0128] Preparation of Microbial Sludge B: Common Chlorella was inoculated onto a blue-green algae culture medium (BG-11 broth), with a light-dark ratio controlled at 14h:12h. Alternating irradiation was performed under a light intensity of 7000 lx. After cultivation at 28℃ to the logarithmic growth phase, the culture was transferred to a centrifuge and centrifuged at 8000 rpm to obtain wet microbial sludge, denoted as Microbial Sludge B. The content of Common Chlorella bacteria in Microbial Sludge B was 5 × 10⁻⁶. 9 CFU / mL.

[0129] Preparation of mixed mycelium sludge C: Mix mycelium sludge A and mycelium sludge B thoroughly at a mass ratio of 1:4.5 at 4℃ to form mixed mycelium sludge C.

[0130] Immobilization and embedding: Mixed bacterial sludge C was inoculated into a 3.5 wt% sodium alginate solution at an inoculation rate of 25%, meaning the volume of inoculated mixed bacterial sludge C accounted for 25% of the volume of the mixed liquid after inoculation. The mixture was thoroughly stirred to form a homogeneous solution. The solution was then added dropwise to a 4.5 wt% calcium chloride solution using a syringe, with the added volume not exceeding 60% of the calcium chloride solution volume. After solidification to form spheres, the calcium chloride solution containing the spheres was transferred to a 4°C refrigerator and allowed to stand for 10 hours. After removal, spheres with a diameter of approximately 5 mm were selected using custom-made sieves with apertures of 4.5 mm and 5.5 mm. The surface residue was rinsed with sterile physiological saline, and after draining, microbial spheres 2 were obtained.

[0131] Construction steps of membrane treatment reactor 1:

[0132] like Figure 1 As shown, a membrane treatment reactor 1 is constructed, specifically including: the height-to-diameter ratio of the membrane treatment reactor 1 is set to 3.5:1; visible light sources 4 are uniformly distributed inside the membrane treatment reactor 1, and the intensity of the visible light sources 4 inside the membrane treatment reactor 1 is controlled to 7000 lx / m. 3The system maintains a light-to-dark time ratio of 14h:12h via a controller, alternately controlling the on / off state of the visible light source 4. Micro-nano bubbles with a particle size of 40–80 μm, generated by a micro-nano bubble generator 6, are introduced into the bottom of the membrane treatment reactor 1 to control the dissolved oxygen level in the reactor to 3.5 mg / L. A composite photocatalytic membrane 3 assembly is fixedly installed in the upper part (above halfway) of the membrane treatment reactor 1. The composite photocatalytic membrane 3 is used at a depth of 28 cm³. 2 / L, specifically, 28cm per 1L of wastewater. 2 3. Composite photocatalytic membrane with area 3.

[0133] Microbial ball 2 inoculation steps:

[0134] Microbial balls 2 are inoculated into membrane treatment reactor 1 at an inoculation rate of 30%, meaning the volume of inoculated microbial balls 2 is 30% of the effective volume of membrane treatment reactor 1. The effective volume of membrane treatment reactor 1 is the volume of membrane treatment reactor 1 after deducting the volume of various reactor components (including the composite photocatalytic membrane 3 component).

[0135] Wastewater treatment steps:

[0136] The automotive painting wastewater is continuously and evenly introduced from the bottom of the membrane treatment reactor 1, with the hydraulic retention time controlled at 20 hours, the pH inside the membrane treatment reactor 1 controlled at 7.3, and the operating temperature controlled at 28°C. The water is pumped out using an external effluent pump 5 to achieve membrane filtration effluent.

[0137] After the reactor operated continuously for 30 days, the transmembrane pressure difference was 13.2 kPa. The changes in water quality before and after wastewater treatment were measured as follows:

[0138] Testing items Before processing After processing COD (mg / L) 1650 92 Total phosphorus (mg / L) 38 3.6 Petroleum products (mg / L) 62 4.4

[0139] The wastewater purification effect in Example 3 is comparable to that in Example 1.

[0140] Comparative Example 1

[0141] Construction steps of membrane treatment reactor 1:

[0142] like Figure 1 As shown, a membrane treatment reactor 1 is constructed, specifically including: the height-to-diameter ratio of the membrane treatment reactor 1 is set to 4:1; visible light sources 4 are uniformly distributed inside the membrane treatment reactor 1, and the intensity of the visible light sources 4 inside the membrane treatment reactor 1 is controlled to 6000 lx / m. 3The system maintains a light-dark time ratio of 12h:12h using a controller, alternately controlling the on / off state of the visible light source 4. Micro-nano bubbles with a particle size of 40–80 μm, generated by a micro-nano bubble generator 6, are introduced into the bottom of the membrane treatment reactor 1 to control the dissolved oxygen level in the reactor to 4 mg / L. A composite photocatalytic membrane 3 assembly is fixedly installed in the upper part (above halfway) of the membrane treatment reactor 1. The composite photocatalytic membrane 3 is 28 cm³. 2 / L, specifically, 28cm per 1L of wastewater. 2 3. Composite photocatalytic membrane with area 3.

[0143] Activated sludge inoculation steps:

[0144] Activated sludge is inoculated into membrane treatment reactor 1 at a rate of 35%, meaning the volume of inoculated activated sludge is 35% of the effective volume of membrane treatment reactor 1. The effective volume of membrane treatment reactor 1 is the volume of membrane treatment reactor 1 after deducting the volume of various reactor components (including the composite photocatalytic membrane 3 component).

[0145] Wastewater treatment steps:

[0146] The automotive painting wastewater is continuously and evenly introduced from the bottom of the membrane treatment reactor 1, with the hydraulic retention time controlled at 24 hours, the pH inside the membrane treatment reactor 1 controlled at 7.5, and the operating temperature controlled at 30°C. The water is pumped out using an external effluent pump 5 to achieve membrane filtration effluent.

[0147] After the reactor operated continuously for 30 days, the transmembrane pressure difference was 18.2 kPa. The changes in water quality before and after wastewater treatment were measured as follows:

[0148] Testing items Before processing After processing COD (mg / L) 1650 302 Total phosphorus (mg / L) 38 11 Petroleum products (mg / L) 62 16

[0149] Compared to Example 2, Comparative Example 1 used commercially available sludge instead of microbial balls 2. After the reactor operation was completed, the transmembrane pressure difference of the composite photocatalytic membrane 3 in Comparative Example 1 was 18.2 kPa, which was much higher than the 12.9 kPa transmembrane pressure difference in Example 2. This indicates that the composite photocatalytic membrane 3 in Comparative Example 1 was more heavily polluted and clogged.

[0150] Specifically, the lack of microbial balls 2 in Comparative Example 1 severely affected the degradation of oil pollution, leading to the accumulation of oil on the composite photocatalytic membrane 3, causing blockage and further affecting the purification and treatment of wastewater; at the same time, the lack of microbial balls 2 also resulted in a reduction in the degradation of total phosphorus.

[0151] Comparative Example 2

[0152] Preparation steps of microbial balls 2:

[0153] Preparation of mycotic sludge A: Bacillus tropicalis was inoculated into LB liquid medium and cultured at 30°C until the logarithmic growth phase. The culture was then transferred to a centrifuge and centrifuged at 8000 rpm to obtain wet mycotic sludge, denoted as mycotic sludge A. The content of Bacillus tropicalis in mycotic sludge A was 5 × 10⁻⁶. 10 CFU / mL.

[0154] Preparation of Microbial Sludge B: Common Chlorella was inoculated onto a blue-green algae culture medium (BG-11 broth), with a light-dark ratio of 12h:12h. Alternating irradiation was performed under a light intensity of 5000 lx at 25℃ until the logarithmic growth phase. The culture was then transferred to a centrifuge and centrifuged at 8000 rpm to obtain wet microbial sludge, denoted as Microbial Sludge B. The content of Common Chlorella bacteria in Microbial Sludge B was 2 × 10⁻⁶. 9 CFU / mL.

[0155] Preparation of mixed microbial sludge C: Mix microbial sludge A and microbial sludge B thoroughly at a mass ratio of 1:5 at 4℃ to form mixed microbial sludge C.

[0156] Immobilization and embedding: Mixed bacterial sludge C was inoculated into a 3 wt% sodium alginate solution, with an inoculation amount of 30%, meaning the volume of inoculated mixed bacterial sludge C accounted for 30% of the volume of the mixed liquid after inoculation. The mixture was thoroughly stirred to form a homogeneous solution. The solution was then added dropwise to a 5 wt% calcium chloride solution using a syringe, with the volume of the added solution not exceeding 60% of the volume of the calcium chloride solution. After solidification to form spheres, the calcium chloride solution containing the spheres was transferred to a 4°C refrigerator and allowed to stand for 15 hours. After removal, spheres with a diameter of 4–6 mm were screened using custom-made sieves with apertures of 4 mm and 6 mm, respectively. The surface residual liquid was rinsed with sterile physiological saline, and after draining, microbial spheres 2 were obtained.

[0157] Construction steps of membrane treatment reactor 1:

[0158] like Figure 1 As shown, a membrane treatment reactor 1 is constructed, specifically including: the height-to-diameter ratio of the membrane treatment reactor 1 is set to 4:1; the interior of the membrane treatment reactor 1 is kept dark as there is no visible light source 4; micro-nano bubbles with a particle size of 40-80 μm are introduced into the bottom of the membrane treatment reactor 1 by a micro-nano bubble generator 6 to control the dissolved oxygen in the reactor to 4 mg / L; a composite photocatalytic membrane 3 assembly is fixedly installed in the upper part (above 1 / 2) of the membrane treatment reactor 1. The amount of composite photocatalytic membrane 3 is 28 cm³. 2 / L, specifically, 28cm per 1L of wastewater. 2 3. Composite photocatalytic membrane with area 3.

[0159] Microbial ball 2 inoculation steps:

[0160] Microbial balls 2 are inoculated into membrane treatment reactor 1 at an inoculation rate of 35%, meaning the volume of inoculated microbial balls 2 is 35% of the effective volume of membrane treatment reactor 1. The effective volume of membrane treatment reactor 1 is the volume of membrane treatment reactor 1 after deducting the volume of various reactor components (including the composite photocatalytic membrane 3 component).

[0161] Wastewater treatment steps:

[0162] The automotive painting wastewater is continuously and evenly introduced from the bottom of the membrane treatment reactor 1, with the hydraulic retention time controlled at 24 hours, the pH inside the membrane treatment reactor 1 controlled at 7.5, and the operating temperature controlled at 30°C. The water is pumped out using an external effluent pump 5 to achieve membrane filtration effluent.

[0163] After the reactor operated continuously for 30 days, the transmembrane pressure difference was 24.5 kPa. The changes in water quality before and after wastewater treatment were measured as follows:

[0164] Testing items Before processing After processing COD (mg / L) 1650 185 Total phosphorus (mg / L) 38 17.8 Petroleum products (mg / L) 62 14.7

[0165] Compared to Example 2, the light source in the membrane treatment reactor 1 of Comparative Example 2 was kept off. After the reactor operation was completed, the transmembrane pressure difference of the composite photocatalytic membrane 3 of Comparative Example 2 was 24.5 kPa, which was much higher than the transmembrane pressure difference of 12.9 kPa in Example 2. This indicates that the degree of fouling and clogging of the composite photocatalytic membrane 3 of Comparative Example 2 was higher.

[0166] Specifically, although microbial balls 2 were inoculated in Comparative Example 2, the lack of light prevented the growth and colonization of Chlorella vulgaris, affecting the removal of phosphorus and the synthesis of organic matter. This also prevented the synthesis of nutrients for Bacillus tropicalis, indirectly impacting the degradation of oil. Consequently, microbial balls 2 could not effectively perform their intended function, leading to the accumulation of oil on the composite photocatalytic membrane 3. The biospheres themselves also exacerbated the blockage, further affecting wastewater purification. Simultaneously, the lack of light also affected the purification effect of the composite photocatalytic membrane 3 itself.

[0167] Comparative Example 3

[0168] Preparation steps of microbial balls 2:

[0169] Preparation of mycotic sludge A: Bacillus tropicalis was inoculated into LB liquid medium and cultured at 30°C until the logarithmic growth phase. The culture was then transferred to a centrifuge and centrifuged at 8000 rpm to obtain wet mycotic sludge, denoted as mycotic sludge A. The content of Bacillus tropicalis in mycotic sludge A was 5 × 10⁻⁶. 10 CFU / mL.

[0170] Preparation of Microbial Sludge B: Common Chlorella was inoculated onto a blue-green algae culture medium (BG-11 broth), with a light-dark ratio of 12h:12h. Alternating irradiation was performed under a light intensity of 5000 lx at 25℃ until the logarithmic growth phase. The culture was then transferred to a centrifuge and centrifuged at 8000 rpm to obtain wet microbial sludge, denoted as Microbial Sludge B. The content of Common Chlorella bacteria in Microbial Sludge B was 2 × 10⁻⁶. 9 CFU / mL.

[0171] Preparation of mixed microbial sludge C: Mix microbial sludge A and microbial sludge B thoroughly at a mass ratio of 1:5 at 4℃ to form mixed microbial sludge C.

[0172] Immobilization and embedding: Mixed bacterial sludge C was inoculated into a 3 wt% sodium alginate solution, with an inoculation amount of 30%, meaning the volume of inoculated mixed bacterial sludge C accounted for 30% of the volume of the mixed liquid after inoculation. The mixture was thoroughly stirred to form a homogeneous solution. The solution was then added dropwise to a 5 wt% calcium chloride solution using a syringe, with the volume of the added solution not exceeding 60% of the volume of the calcium chloride solution. After solidification to form spheres, the calcium chloride solution containing the spheres was transferred to a 4°C refrigerator and allowed to stand for 15 hours. After removal, spheres with a diameter of 4–6 mm were screened using custom-made sieves with apertures of 4 mm and 6 mm, respectively. The surface residual liquid was rinsed with sterile physiological saline, and after draining, microbial spheres 2 were obtained.

[0173] Construction steps of membrane treatment reactor 1:

[0174] like Figure 1 As shown, a membrane treatment reactor 1 is constructed, specifically including: the height-to-diameter ratio of the membrane treatment reactor 1 is set to 4:1; visible light sources 4 are uniformly distributed inside the membrane treatment reactor 1, and the intensity of the visible light sources 4 inside the membrane treatment reactor 1 is controlled to 6000 lx / m. 3 The system maintains a light-dark time ratio of 12h:12h using a controller, alternately controlling the on / off state of the visible light source 4. Bubbles generated by a microporous aeration disc are introduced into the bottom of the membrane treatment reactor 1. A composite photocatalytic membrane 3 assembly is fixedly installed at the upper part (above 1 / 2 of the reactor's length) of the membrane treatment reactor 1. The composite photocatalytic membrane 3 is 28 cm³. 2 / L, specifically, 28cm per 1L of wastewater. 2 3. Composite photocatalytic membrane with area 3.

[0175] Microbial ball 2 inoculation steps:

[0176] Microbial balls 2 are inoculated into membrane treatment reactor 1 at an inoculation rate of 35%, meaning the volume of inoculated microbial balls 2 is 35% of the effective volume of membrane treatment reactor 1. The effective volume of membrane treatment reactor 1 is the volume of membrane treatment reactor 1 after deducting the volume of various reactor components (including the composite photocatalytic membrane 3 component).

[0177] Wastewater treatment steps:

[0178] The automotive painting wastewater is continuously and evenly introduced from the bottom of the membrane treatment reactor 1, with the hydraulic retention time controlled at 24 hours, the pH inside the membrane treatment reactor 1 controlled at 7.5, and the operating temperature controlled at 30°C. The water is pumped out using an external effluent pump 5 to achieve membrane filtration effluent.

[0179] After the reactor operated continuously for 30 days, the transmembrane pressure difference was 20.2 kPa. The changes in water quality before and after wastewater treatment were measured as follows:

[0180]

[0181]

[0182] Compared to Example 2, Comparative Example 3 uses a microporous aeration disc (ordinary aeration process) instead of the micro-nano bubble generator 6. After the reactor operation is completed, the transmembrane pressure difference of the composite photocatalytic membrane 3 in Comparative Example 3 is 20.2 kPa, which is much higher than the 12.9 kPa transmembrane pressure difference in Example 2. This indicates that the composite photocatalytic membrane 3 in Comparative Example 3 has a higher degree of fouling and clogging.

[0183] Specifically, because Comparative Example 3 uses a microporous aeration disc (ordinary aeration process) instead of the micro-nano bubble generator 6, the oxygen content and oxygen retention time in the wastewater are reduced, which is not conducive to the full suspension and expansion of the microbial balls 2. This, in turn, affects the degradation of organic pollutants, especially oil pollutants, by Bacillus tropicalis in the microbial balls 2, leading to the accumulation of oil on the composite photocatalytic membrane 3, causing blockage, and further affecting the purification and treatment of wastewater.

[0184] Furthermore, the reduced activity of tropical Bacillus also leads to a decrease in the carbon dioxide produced during its metabolism, which indirectly affects the degradation of total phosphorus by common Chlorella.

[0185] Meanwhile, the trace amounts of hydroxyl radicals generated by the micro-nano bubbles will also disappear, which is not conducive to the removal of organic pollutants from wastewater and the cleaning of the photocatalytic membrane.

[0186] The above description provides an illustrative overview of the present invention and its embodiments. This description is not restrictive, and the embodiments shown are merely one example of the invention's implementation. Actual implementations are not limited to these examples. Therefore, if those skilled in the art are inspired by this description and design similar implementations and examples without departing from the spirit of the invention, such designs should fall within the scope of protection of the present invention.

Claims

1. A treatment process for high-oil and high-phosphorus wastewater, characterized in that, include: Wastewater is treated using microbial balls; Photocatalytic treatment of wastewater using photocatalytic membranes; The treatment of wastewater by the microbial balls and the photocatalytic treatment of wastewater by the photocatalytic membrane are carried out in the same reactor; The photocatalytic membrane is positioned above half the height of the reactor. The dissolved oxygen content of wastewater is adjusted to 3-4 mg / L by using micro-nano bubbles with a particle size of 40-80 μm. The microbial balls are 4-6 mm in diameter and contain tropical Bacillus and common Chlorella. Microbial balls with a particle size of 4–6 mm are mainly distributed in the area below 1 / 2 the height of the reactor in reactors with continuous aeration and water inflow.

2. The treatment process for high-oil and high-phosphorus wastewater according to claim 1, characterized in that, The total volume is calculated by combining the volumes of the microbial balls and the wastewater, with the volume of the microbial balls accounting for 25% to 35%.

3. The treatment process for high-oil and high-phosphorus wastewater according to claim 2, characterized in that, When using microbial balls to treat wastewater, the treatment conditions include: The hydraulic retention time is 16–24 hours; The pH of the water body is 7.0–7.5; The temperature is 25–30℃; The intensity of visible light sources is 5000–7000 lx / m 3 ; The light source is alternately turned on and off, and the ratio of light to dark time is controlled to be (12h~14h):12h.

4. The treatment process for high-oil and high-phosphorus wastewater according to claim 3, characterized in that, When using photocatalytic membranes to treat wastewater via photocatalysis, the treatment conditions include: The hydraulic residence time is 16–24 hours; The pH of the water body is 7.0–7.5; The temperature is 25-30℃.

5. The treatment process for high-oil and high-phosphorus wastewater according to any one of claims 1 to 4, characterized in that, The processing conditions during the photocatalytic treatment also include: The intensity of visible light sources is 5000–7000 lx / m 3 ; The light source is alternately turned on and off, and the ratio of light to dark time is controlled to be (12h~14h):12h.

6. The treatment process for high-oil and high-phosphorus wastewater according to claim 5, characterized in that, The microbial balls are obtained through the following steps: The tropical Bacillus was cultured to the logarithmic growth phase and centrifuged to obtain wet bacterial sludge, which was denoted as bacterial sludge A. The common Chlorella was cultured to the logarithmic growth phase, and the wet bacterial sludge was obtained by centrifugation, which was denoted as bacterial sludge B. Mix the fungal mud A and the fungal mud B evenly and record it as mixed fungal mud C; The mixed bacterial sludge C was immobilized and embedded to obtain microbial balls; During the cultivation of *Chlorella vulgaris*, visible light irradiation was applied at an intensity of 5000–7000 lx. The light source was alternately switched on and off, with a light-to-dark time ratio of (12–14 h):12 h. The temperature was maintained at 25–28 °C, and the culture was centrifuged at 6000–10000 rpm to obtain bacterial sludge B. The content of *Chlorella vulgaris* in bacterial sludge B was 1 × 10⁻⁶. 9 ~5×10 9 CFU / mL.

7. The treatment process for high-oil and high-phosphorus wastewater according to claim 6, characterized in that, The preparation process of the bacterial sludge A includes: inoculating the Bacillus tropicalis into LB liquid medium, culturing at 30-35℃ to the logarithmic growth phase, and centrifuging at 6000-10000 rpm to obtain bacterial sludge A, wherein the content of Bacillus tropicalis in bacterial sludge A is 2×10⁻⁶. 10 ~8×10 10 CFU / mL; And / or, The preparation process of the mixed fungal mud C includes: mixing the fungal mud A and the fungal mud B thoroughly and evenly at a mass ratio of 1:(4-5) under the condition of 2-6℃ to form the mixed fungal mud C; And / or, The immobilization and embedding method of the mixed bacterial sludge C includes: The mixed bacterial mud C is inoculated into a 2-5 wt% sodium alginate solution, with an inoculation amount of 20-30%, and mixed evenly to obtain a mixed solution; The mixture is added dropwise to a 3-10 wt% calcium chloride solution and allowed to stand until it solidifies into spheres; The calcium chloride solution containing the small spheres was refrigerated at 4°C and allowed to stand for 10–15 hours. The microspheres were rinsed with sterile saline to remove residual liquid from their surface, and then drained to obtain microbial spheres.

8. The treatment process for high-oil and high-phosphorus wastewater according to claim 1, characterized in that, The amount of the photocatalytic membrane used is 25-30 cm. 2 / L; The photocatalyst loading in the photocatalytic membrane is 5–8 mg / cm³. 2 .

9. The treatment process for high-oil and high-phosphorus wastewater according to any one of claims 1-4 and 6-8, characterized in that, The wastewater before treatment has a COD of 1500–1800 mg / L, a petroleum content of 50–80 mg / L, and a total phosphorus content of 25–50 mg / L.

10. A treatment system for high-oil and high-phosphorus wastewater, characterized in that: It consists of an influent system, a membrane treatment reactor system, and an effluent system, in sequence. The membrane treatment reactor system includes a membrane treatment reactor, a visible light source, a photocatalytic membrane, a micro / nano bubble generator, and microbial balls; The water inlet system is located at the bottom of the membrane treatment reactor; The height-to-diameter ratio of the membrane treatment reactor is (3-4):1; The visible light source is located inside the membrane treatment reactor, and the light-to-dark time ratio inside the reactor can be controlled by turning the visible light source on and off. The micro-nano bubble generator introduces micro-nano bubbles with a particle size of 40-80 μm from the bottom of the membrane treatment reactor, thereby controlling the dissolved oxygen content in the membrane treatment reactor; The photocatalytic membrane is positioned above half the height of the membrane treatment reactor; The diameter of the microbial balls is 4-6 mm; Microbial balls with a particle size of 4–6 mm are mainly distributed in the region below 1 / 2 height of the membrane treatment reactor in a continuously aerated and influent membrane treatment reactor. The photocatalytic membrane is connected to a water pump, and the water pump is connected to the water outlet system.

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