A modified carrier biofilm and a preparation method and application thereof

Abstract

The application discloses a modified carrier biofilm and a preparation method and application thereof, and the preparation of the modified carrier biofilm comprises the following steps: preparing a porous carrier with nano-Fe3O4 fixed therein, soaking the porous carrier into activated sludge, culturing microorganisms in the porous carrier loaded with the activated sludge, forming a biofilm on the surface and inside of the porous carrier, and obtaining the modified carrier biofilm. The modified carrier biofilm prepared by the application has the advantages of good structural stability, strong biological activity and the like, is a novel biofilm material with excellent performance, can be widely used for degrading organic pollutants in the environment, can effectively convert the organic pollutants into low-toxic or non-toxic metabolic products, has high use value, and has good application prospect. The preparation method also has the advantages of simple process, convenient operation, low preparation cost and the like, is suitable for large-scale preparation, is convenient for industrial application, and has important significance for promoting the wide application of the modified carrier biofilm in the field of environmental governance.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterials and microbial pollutant removal, and relates to a modified carrier biofilm, its preparation method and application. Background Technology

[0002] Since their discovery, antibiotics have been used in medical and health care, animal husbandry, and other fields. Because antibiotics cannot be completely metabolized by humans and other animals, large quantities of them enter the environment through excretion, causing significant harm. Therefore, effectively removing antibiotics from the environment to reduce their harm to the ecological environment and human health is a pressing technical problem that needs to be solved.

[0003] Utilizing microorganisms to degrade organic pollutants is a current research hotspot in environmental remediation. Using organic pollutants as a carbon source for microbial growth and biodegrading antibiotics can transform environmental organic pollutants into non-toxic or low-toxic metabolites. However, the biodegradation of organic pollutants by microorganisms has significant limitations. They are highly susceptible to environmental factors and face intense competition from native microorganisms, hindering rapid and thorough degradation and resulting in low degradation rates and unstable degradation effects. To address these issues, researchers have proposed immobilized microbial technology. By fixing microorganisms in a limited spatial area, the toxicity of the microorganisms to the target pollutants is increased, thereby improving the removal rate of the target pollutants. However, existing methods for utilizing immobilized microorganisms to degrade antibiotics still have the following drawbacks: the carrier material is easily decomposed, resulting in poor stability of the immobilized microorganisms, making them difficult to reuse or resulting in poor reuse efficiency; the carrier material has a small specific surface area, limiting the growth and reproduction space for microorganisms, making it difficult to multiply them in large quantities, thus resulting in poor degradation efficiency and removal effect on the target pollutant; the microorganisms are of limited species, requiring domestication to improve their tolerance to the target pollutant, and they are highly specific, showing good removal effect only on the target pollutant, making it difficult to widely degrade different organic pollutants. Therefore, obtaining a modified carrier biofilm with good structural stability and strong biological activity, as well as a matching method for preparing a modified carrier biofilm with simple process, convenient operation, and low preparation cost, is of great significance for effectively removing antibiotics from the environment using microorganisms and reducing environmental pollution and ecological imbalance caused by antibiotics. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a modified carrier biomembrane with good structural stability and strong biological activity, as well as its preparation method and application.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution.

[0006] A method for preparing a modified carrier biomembrane includes the following steps:

[0007] S1. Preparation of porous carriers immobilized with nano-ferric oxide;

[0008] S2. The porous carrier with nano-iron oxide fixed is immersed in activated sludge to obtain a porous carrier loaded with activated sludge.

[0009] S3. Microorganisms in a porous carrier loaded with activated sludge are cultured to form a biofilm on the surface and inside the porous carrier, thus obtaining a modified carrier biofilm.

[0010] A further improvement to the above preparation method is that, in step S1, the preparation method of the porous carrier with immobilized nano-ferric oxide includes the following steps:

[0011] (1) Mix nano-iron oxide, porous carrier and solvent, and sonicate to obtain a suspension;

[0012] (2) The suspension is heated to remove the solvent and a porous carrier with nano-iron oxide is obtained.

[0013] In a further improvement of the above preparation method, in step (1), the mass ratio of the nano-iron oxide to the porous carrier is 0.5 to 1:1; the particle size of the nano-iron oxide is 20 nm; the porous carrier is polyurethane sponge and / or polyvinyl chloride sponge; the solvent is anhydrous ethanol; and the ultrasonic time is 20 min to 30 min.

[0014] The above preparation method is further improved in step (2), wherein the heating is first carried out in a water bath at 60°C until the volume of the direct suspension is reduced to less than one-fifth of the total volume, and then transferred to an oven at 60°C for drying until the solvent is completely evaporated; the heating in the water bath is stirred once every hour for 30 seconds each time; the heating in the oven is stirred once every 0.5 hours for 30 seconds each time; after the solvent is completely removed, the following treatment is also included: the porous carrier with nano-iron oxide fixed is ultrasonicated for 1 min to 3 min, washed with water 3 times, and dried.

[0015] In a further improvement to the above preparation method, in step S2, the soaking is carried out under dark conditions; the soaking process also includes stirring the activated sludge at a speed of 120 r / min; the temperature of the activated sludge is controlled at 25°C during the soaking process; the soaking time is 24 h; and the activated sludge is derived from the secondary sedimentation tank of a wastewater treatment plant.

[0016] In a further improvement to the above preparation method, step S3, the cultivation of microorganisms in the porous carrier loaded with activated sludge, further includes adding nutrients to the culture system, such that the culture system containing added nutrients contains the following components: 330 mg / L sodium acetate, 29 mg / L NH4Cl, 8 mg / L Na2HPO4·2H2O, and 4 mg / L NaH2PO4; the nutrients are added every 48 hours during the cultivation of microorganisms in the porous carrier loaded with activated sludge; the cultivation of microorganisms in the porous carrier loaded with activated sludge is carried out under dark conditions; the cultivation of microorganisms in the porous carrier loaded with activated sludge also includes stirring the culture system at a speed of 120 r / min; the temperature of the culture system is controlled at 25°C during the cultivation of microorganisms in the porous carrier loaded with activated sludge; and the cultivation time is 5 to 7 days.

[0017] As a general technical concept, the present invention also provides a modified carrier biomembrane, which is prepared by the above-described preparation method.

[0018] The modified carrier biofilm described above is further improved by including a porous carrier and nano-iron oxide, wherein the nano-iron oxide is fixed on the porous carrier to form a porous carrier with fixed nano-iron oxide; a biofilm grows on the surface and inside of the porous carrier with fixed nano-iron oxide.

[0019] As a general technical concept, the present invention also provides an application of the above-mentioned modified carrier biofilm in the treatment of antibiotic wastewater.

[0020] The above-mentioned application, further improved, includes the following steps: mixing the modified carrier biofilm with antibiotic wastewater, culturing the microorganisms in the modified carrier biofilm, and completing the treatment of antibiotic wastewater; the ratio of the dry weight of the modified carrier biofilm to the volume of the antibiotic wastewater is 0.03g~0.1g∶200mL.

[0021] Further improvements to the above application include the addition of nutrients to the wastewater during the cultivation of microorganisms in the modified carrier biofilm. The added nutrients result in the wastewater containing the following components: 330 mg / L sodium acetate, 29 mg / L NH4Cl, 8 mg / L Na2HPO4·2H2O, and 4 mg / L NaH2PO4. Nutrients are added every 48 hours during the cultivation of the microorganisms in the modified carrier biofilm. The cultivation of the microorganisms in the modified carrier biofilm is conducted in darkness. The cultivation process also includes stirring the wastewater at a speed of 120 r / min. The temperature of the wastewater is controlled at 25°C. The cultivation time is 24 h to 72 h. The antibiotic in the antibiotic wastewater is oxytetracycline, and the initial concentration of the antibiotic in the antibiotic wastewater is ≤10 mg / L.

[0022] Compared with the prior art, the advantages of the present invention are as follows:

[0023] (1) In view of the defects of existing immobilized microorganisms such as poor structural stability and low biological activity, this invention creatively proposes a method for preparing modified carrier biofilm. First, nano-iron oxide is fixed on a porous carrier. The porous structure of the porous carrier can be used to firmly fix the nano-iron oxide material, thereby forming a porous carrier with large specific surface area, many active sites and good structural stability. Then, microorganisms in activated sludge are cultured. During the culture process, the porous carrier with nano-iron oxide can serve as a place for the enrichment and growth of microorganisms, which is conducive to the rapid and large-scale reproduction of microorganisms. At the same time, nano-iron oxide can promote the growth of microorganisms, thereby forming a biofilm with a microbial structure similar to that of the original activated sludge on the surface of the porous carrier. It can also enhance the stability of the microbial community and make the biofilm exhibit better biological activity. More importantly, the coating effect of the biofilm can effectively prevent nano-iron oxide from detaching from the porous carrier, thus further enhancing the structural stability of the modified carrier biofilm. The modified carrier biofilm prepared by this invention possesses advantages such as good structural stability and strong biological activity, making it a novel biofilm material with excellent performance. It can be widely used to degrade organic pollutants in the environment, effectively converting them into low-toxicity or non-toxic metabolites, demonstrating high practical value and promising application prospects. Furthermore, the preparation method of this invention is simple, convenient, and low-cost, suitable for large-scale production and industrial application, which is of great significance for promoting the widespread application of modified carrier biofilms in the field of environmental remediation.

[0024] (2) The present invention also provides an application of modified carrier biofilm in the treatment of antibiotic wastewater. By mixing the modified carrier biofilm with antibiotic wastewater and culturing the microorganisms in the modified carrier biofilm, the antibiotics in the wastewater can be efficiently and thoroughly removed by the biodegradation of the microorganisms. It has the advantages of simple operation, high removal efficiency and high mineralization rate. Taking oxytetracycline as an example, the removal rate of oxytetracycline can reach more than 85% after 3 days of cultivation, which can effectively remove oxytetracycline. In contrast, the removal rate of conventional immobilized microorganisms of oxytetracycline is less than 75% after 3 days of cultivation. It can be seen that when using the modified carrier biofilm of the present invention to treat antibiotic wastewater, it can effectively remove antibiotics in the wastewater and effectively remove organic pollutants in the environment. Attached Figure Description

[0025] To make the objectives, technical solutions, and advantages of the embodiments 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.

[0026] Figure 1 This is a scanning electron microscope image of the porous carrier with immobilized nano-Fe3O4 prepared in Example 1 of the present invention.

[0027] Figure 2 This is a comparison chart of the dry weight of the original carrier biofilm and the modified carrier biofilm in Example 1 of the present invention.

[0028] Figure 3 This is a diagram showing the phylum-level microbial community analysis of the activated sludge used in Example 1 of the present invention.

[0029] Figure 4 This is a diagram showing the phylum-level microbial community analysis of the original carrier biofilm in Example 1 of the present invention.

[0030] Figure 5 This is a diagram showing the phylum-level microbial community analysis of the modified carrier biofilm in Example 1 of the present invention.

[0031] Figure 6 This is a diagram showing the removal effect of the modified carrier biofilm on oxytetracycline in Example 2 of the present invention.

[0032] Figure 7 This is a diagram showing the mineralization effect of the modified carrier biofilm on oxytetracycline in Example 2 of the present invention. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention. All materials and instruments used in the following embodiments are commercially available.

[0034] Example 1

[0035] A method for preparing a modified carrier biomembrane includes the following steps:

[0036] S1. Preparation of porous carriers immobilized with nano-ferric oxide:

[0037] (1) Preparation of primitive biofilm carriers

[0038] Commercially available PVC porous sponge was cut into uniform cubes of 10mm×10mm×10mm, washed three times with ultrapure water, and then thoroughly dried in an oven to obtain a porous carrier.

[0039] (2) Immobilization of nano Fe3O4

[0040] At a weight ratio of 1:1, commercially available nano-Fe3O4 and a porous support were placed in a 250 mL beaker. 100 mL of anhydrous ethanol was added to the beaker, and the mixture was sonicated for 30 min to obtain a homogeneous suspension. Subsequently, the suspension was heated in a water bath, and stirred with a glass rod once every hour for 30 s each time, until the volume of the suspension decreased to 20 mL. The suspension was then transferred to an oven, and stirred with a glass rod once every 0.5 hours for 30 s each time, until the liquid was completely evaporated. The solid material was sonicated for 3 min, washed three times with ultrapure water, and dried again in an oven to obtain a porous support with nano-Fe3O4 fixed in place.

[0041] Figure 1 This is a scanning electron microscope (SEM) image of the porous carrier with immobilized nano-ferric oxide prepared in Example 1 of this invention. Figure 1 It is known that in the porous carrier with immobilized nano-Fe3O4 prepared by the present invention, nano-Fe3O4 can be uniformly and fixedly distributed on the surface of the carrier.

[0042] S2. Under dark conditions, the porous carrier with nano-iron oxide fixed is immersed in activated sludge (the activated sludge comes from the secondary sedimentation tank of a sewage treatment plant in Changsha City) for 24 hours. During the immersion process, the activated sludge is stirred at a speed of 120 r / min and the temperature of the activated sludge is controlled at 25℃, so that the activated sludge fills into the interior of the porous carrier, and a porous carrier loaded with activated sludge is obtained.

[0043] S3. A porous carrier loaded with activated sludge is mixed with nutrients, and the microorganisms are cultured in the dark for 6 days at a rotation speed of 120 r / min and a temperature of 25℃. A biofilm forms on the surface and inside the porous carrier, resulting in a modified carrier biofilm. In this step, after adding nutrients, the culture system contains the following components: 330 mg / L sodium acetate, 29 mg / L NH4Cl, 8 mg / L Na2HPO4·2H2O, and 4 mg / L NaH2PO4. New nutrients are added every 48 hours during the culture process.

[0044] The modified carrier biofilm prepared in this embodiment includes a porous carrier and nano-iron oxide. The nano-iron oxide is fixed on the porous carrier to form a porous carrier with fixed nano-iron oxide. A biofilm grows on the surface and inside of the porous carrier with fixed nano-iron oxide. The porous carrier is a PVC porous sponge and the nano-iron oxide has a particle size of 20 nm.

[0045] Take the modified carrier biomembrane prepared in Example 1 of this invention and the original carrier biomembrane (prepared in basically the same way as the modified carrier biomembrane, the only difference being that the original carrier biomembrane did not have nano-iron oxide fixed), dry them, and record their final mass. The difference between the two masses is the dry weight of the biomembrane, and the specific value is as follows: Figure 2 As shown.

[0046] Figure 2 This is a comparison chart of the dry weight of the original carrier biofilm and the modified carrier biofilm in Example 1 of the present invention. Figure 2 It can be seen that, compared with the original carrier biofilm, the dry weight of the modified carrier biofilm prepared by the present invention is increased by 21%, which indicates that the introduction of nano-ferric oxide in the present invention will have a positive impact on the degradation of microorganisms.

[0047] Microbial community analysis was performed on the modified carrier biofilm prepared in Example 1 of this invention and the original carrier biofilm (prepared using essentially the same method as the modified carrier biofilm, the only difference being that the original carrier biofilm did not have nano-iron oxide immobilized).

[0048] Ten cultured modified carrier biofilms and ten original carrier biofilms were placed in 50 mL centrifuge tubes. 50 mM PBS buffer (pH 7) was added, and the tubes were sonicated in a water bath for 3 minutes to detach the biofilms from the carriers. The suspensions were then centrifuged at 10,000 rpm for 10 minutes, and the microbial community composition of the precipitate and the original sludge was analyzed. Specific analytical results are as follows: Figure 3 , Figure 4 and Figure 5 As shown.

[0049] Figure 3This is a diagram showing the phylum-level microbial community analysis of the activated sludge used in Example 1 of the present invention.

[0050] Figure 4 This is a diagram showing the phylum-level microbial community analysis of the original carrier biofilm in Example 1 of the present invention.

[0051] Figure 5 This is a diagram showing the phylum-level microbial community analysis of the modified carrier biofilm in Example 1 of the present invention.

[0052] Depend on Figure 3 , Figure 4 and Figure 5 The comparison shows that the phylum-level microbial community structure of the modified carrier biofilm is more similar to that of the original activated sludge, indicating that fewer microorganisms were limited in growth due to environmental changes during the cultivation process.

[0053] Example 2

[0054] The application of a modified carrier biofilm in the treatment of antibiotic wastewater specifically involves: treating oxytetracycline wastewater using the modified carrier biofilm prepared in Example 1, including the following steps:

[0055] Eight modified carrier biofilms prepared in Example 1 were mixed with 200 mL of wastewater containing oxytetracycline and nutrient solution, so that the concentration of oxytetracycline in the mixture was 10 mg / L, the concentration of NH4Cl was 29 mg / L, the concentration of Na2HPO4·2H2O was 8 mg / L, and the concentration of NaH2PO4 was 4 mg / L. The microorganisms in the modified carrier biofilm were cultured for 72 hours in the dark, with the rotation speed controlled at 120 r / min and the temperature at 25 °C during the culture process, thus completing the treatment of oxytetracycline wastewater.

[0056] Samples were taken at 24h, 48h, and 72h to analyze the concentration and removal effect of oxytetracycline. The removal effect was as follows: Figure 6 As shown; samples were taken at the beginning and end of the reaction to analyze the mineralization effect of oxytetracycline. The mineralization effect is shown in the figure. Figure 7 As shown.

[0057] As a performance comparison, a control group was also set up in this embodiment.

[0058] Control group 1: B, using the original carrier biofilm (prepared in a basically the same way as the modified carrier biofilm, the only difference being that the original carrier biofilm did not have nano-iron oxide fixed) instead of the modified carrier biofilm of this invention to treat oxytetracycline wastewater, with other conditions being the same. Samples were taken at 24h, 48h, and 72h to analyze the concentration of oxytetracycline and the removal effect. The removal effect is as follows: Figure 6 As shown; samples were taken at the beginning and end of the reaction to analyze the mineralization effect of oxytetracycline. The mineralization effect is shown in the figure. Figure 7 As shown.

[0059] Control Group 2: Absorption. A porous carrier immobilized with nano-ferric oxide was used instead of the modified carrier biofilm of this invention to treat oxytetracycline wastewater, with other conditions remaining the same. Samples were taken at 24h, 48h, and 72h to analyze the concentration of oxytetracycline and the removal effect. The removal effect is as follows: Figure 6 As shown; samples were taken at the beginning and end of the reaction to analyze the mineralization effect of oxytetracycline. The mineralization effect is shown in the figure. Figure 7 As shown.

[0060] Figure 6 This image shows the removal effect of the modified carrier biofilm on oxytetracycline in Example 2 of the present invention. Figure 6 It can be seen that the modified carrier biofilm of the present invention has the fastest removal rate and the highest removal rate of oxytetracycline. After 48 hours of degradation, the modified carrier biofilm has reached reaction equilibrium and the removal rate of oxytetracycline has reached more than 80%, while the original carrier biofilm has not reached equilibrium after 72 hours. After 72 hours of degradation, the removal rate of oxytetracycline by the modified carrier biofilm can reach 85.7%, while the removal rate of oxytetracycline by the original carrier is 72.3%.

[0061] Figure 7 This image shows the mineralization effect of the modified carrier biofilm on oxytetracycline in Example 2 of this invention. Figure 7 It can be seen that the modified carrier biofilm of the present invention has a mineralization rate of 57.41% for oxytetracycline, which is much greater than the mineralization rate of the original carrier biofilm for oxytetracycline (37.43%), and the TOC removal rate of oxytetracycline produced by adsorption is 23.61%. Therefore, the modified carrier biofilm of the present invention has a very high removal rate and mineralization rate for organic pollutants.

[0062] In summary, the modified carrier biofilm prepared by this invention has advantages such as good structural stability and strong biological activity. It is a novel biofilm material with excellent performance and can be widely used to degrade organic pollutants in the environment. For example, by mixing the modified carrier biofilm with antibiotic wastewater and culturing the microorganisms in the modified carrier biofilm, the biodegradation of microorganisms can efficiently and thoroughly remove antibiotics from the wastewater. It has advantages such as simple operation, high removal efficiency, and high mineralization rate. It is evident that when using the modified carrier biofilm of this invention to treat antibiotic wastewater, it can effectively remove antibiotics from the wastewater and achieve effective removal of antibiotics from the environment, which is of great significance for the effective control of antibiotic pollution.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall still fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for preparing a modified carrier biomembrane, characterized in that, Includes the following steps: S1. Preparation of a porous support immobilized with nano-ferric oxide; the method for preparing the porous support immobilized with nano-ferric oxide includes the following steps: (1) The nano-iron oxide, porous carrier and solvent are mixed and ultrasonicated to obtain a suspension; the mass ratio of the nano-iron oxide to the porous carrier is 0.5 to 1:1; the particle size of the nano-iron oxide is 20 nm; the porous carrier is polyurethane sponge and / or polyvinyl chloride sponge. (2) The suspension is heated to remove the solvent and a porous carrier with nano-iron oxide is obtained. The heating is carried out in a water bath at 60°C until the volume of the suspension is reduced to less than one-fifth of the total volume. Then it is transferred to an oven at 60°C for drying until all the solvent is evaporated. S2. The porous carrier with nano-iron oxide fixed is immersed in activated sludge to obtain a porous carrier loaded with activated sludge; the immersion is carried out under dark conditions; the activated sludge comes from the secondary sedimentation tank of a sewage treatment plant. S3. Microorganisms in a porous carrier loaded with activated sludge are cultured to form a biofilm on the surface and inside the porous carrier, thus obtaining a modified carrier biofilm.

2. The preparation method according to claim 1, characterized in that, In step (1), the solvent is anhydrous ethanol; the ultrasound time is 20 min to 30 min. In step (2), the water bath is stirred once every hour during the heating process, and the stirring time is 30s each time; the oven is stirred once every 0.5 hours during the heating process, and the stirring time is 30s each time; after the solvent is completely removed, the following treatment is also included: the porous carrier with nano-iron oxide fixed is ultrasonicated for 1 min to 3 min, washed with water 3 times, and dried.

3. The preparation method according to claim 1 or 2, characterized in that, In step S2, the soaking process also includes stirring the activated sludge at a speed of 120 r / min; the temperature of the activated sludge is controlled at 25°C during the soaking process; and the soaking time is 24 h.

4. The preparation method according to claim 1 or 2, characterized in that, In step S3, the cultivation of microorganisms in the porous carrier loaded with activated sludge further includes adding nutrients to the culture system, such that the culture system contains the following components: 330 mg / L sodium acetate, 29 mg / L NH4Cl, 8 mg / L Na2HPO4•2H2O, and 4 mg / L NaH2PO4; the nutrients are added every 48 hours during the cultivation of microorganisms in the porous carrier loaded with activated sludge; the cultivation of microorganisms in the porous carrier loaded with activated sludge is carried out in the dark; the cultivation of microorganisms in the porous carrier loaded with activated sludge also includes stirring the culture system at a speed of 120 r / min; the temperature of the culture system is controlled at 25°C during the cultivation of microorganisms in the porous carrier loaded with activated sludge; and the cultivation time is 5 to 7 days.

5. A modified carrier biomembrane, characterized in that, It is prepared by any one of claims 1 to 4.

6. The application of the modified carrier biofilm as described in claim 5 in the treatment of antibiotic wastewater.

7. The application according to claim 6, characterized in that, The process includes the following steps: mixing the modified carrier biofilm with antibiotic wastewater, culturing the microorganisms in the modified carrier biofilm under light-free conditions, and completing the treatment of the antibiotic wastewater; the dry weight ratio of the modified carrier biofilm to the volume of the antibiotic wastewater is 0.03g~0.1g∶200mL.

8. The application according to claim 7, characterized in that, The cultivation process of microorganisms in the modified carrier biofilm also includes adding nutrients to the wastewater, resulting in the wastewater containing the following components: 330 mg / L sodium acetate, 29 mg / L NH4Cl, 8 mg / L Na2HPO4•2H2O, and 4 mg / L NaH2PO4. Nutrients are added every 48 hours during the cultivation of microorganisms in the modified carrier biofilm. The cultivation process also includes stirring the wastewater at a speed of 120 r / min. The temperature of the wastewater is controlled at 25℃. The cultivation time is 24 h to 72 h. The antibiotic in the antibiotic wastewater is oxytetracycline, and the initial concentration of the antibiotic in the antibiotic wastewater is ≤10 mg / L.

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