Method for regulating UASB (upflow anaerobic sludge blanket) under CIP (cleaning in place) stress by using nano bamboo sawdust biochar and application

Abstract

The invention discloses a method for regulating and controlling UASB (Upflow Anaerobic Sludge Blanket) under CIP (Ciprofloxacin) stress by using physically modified nano bamboo sawdust biochar and application of the physically modified nano bamboo sawdust biochar. Bamboo sawdust is dried, ground, pyrolyzed and ball-milled to obtain the physically modified nano bamboo sawdust biochar, and then the physically modified nano bamboo sawdust biochar is added into a UASB reactor and is used for treating artificially synthesized waste containing ciprofloxacin; the wastewater treatment performance, the qepA / qnrB resistance gene abundance and the flora structure can be synergistically regulated and controlled. According to the application of the method, the abundance of Methanosaeta and Methanosarcina methanogens in a UASB (upflow anaerobic sludge blanket) system can be remarkably improved, the concentration of ciprofloxacin in effluent can be reduced, the COD (chemical oxygen demand) removal rate can be improved, and the method has the advantages of low material cost, simplicity and convenience in operation and high stability, and is suitable for treating high-concentration organic wastewater containing ciprofloxacin.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a method and its application for regulating CIP-stressed UASB using nano-bamboo biochar. Background Technology

[0002] Ciprofloxacin (CIP), a widely used fluoroquinolone antibiotic, is easily discharged into the aquatic environment through wastewater after its extensive use in medical, aquaculture, and other fields, becoming a typical persistent environmental pollutant. Its strong biological activity severely interferes with the normal operation of anaerobic digestion (AD) systems, inhibits the activity of anaerobic microbial metabolic enzymes, reduces the efficiency of organic matter degradation, decreases methane production, and disrupts the acid- and methanogenic bacterial balance, posing a serious challenge to the stable operation of wastewater treatment plants.

[0003] Currently, the main technical means to alleviate the inhibitory effect of ciprofloxacin on anaerobic digestion systems include physical adsorption, chemical oxidation, and microbial community optimization. However, these methods generally suffer from drawbacks such as high cost, complex operation, unstable effects, or difficulty in large-scale application. Biochar, due to its porous structure and excellent adsorption performance, has been gradually applied to enhance the pollution resistance of anaerobic digestion systems. However, the ordinary biochar used in existing technologies has significant shortcomings when treating wastewater containing ciprofloxacin: low adsorption capacity for ciprofloxacin, easy desorption, poor pore structure adaptability, difficulty in effectively protecting functional microbial communities, and high raw material and disposal costs in the long term.

[0004] Nano-biochar, with its ultra-large specific surface area, abundant surface functional groups, and diverse pore structures, exhibits potential advantages in pollutant adsorption and improvement of the microbial microenvironment. Existing studies have shown that nano-biochar can efficiently adsorb different forms of ciprofloxacin and influence the population distribution and metabolic functions of anaerobic microorganisms. However, current technologies have not clearly demonstrated the application of nano-biochar prepared from bamboo shavings through specific physical modifications in upflow anaerobic sludge blanket (UASB) reactors, nor have they achieved synergistic regulation of wastewater treatment performance under ciprofloxacin stress, the abundance of specific resistance genes, and core methanogenic bacteria, making it difficult to meet the demands for efficient, economical, and environmentally friendly treatment in practical engineering. Therefore, developing a targeted, effective, and easily scalable nano-biochar regulation technology is of great significance for alleviating ciprofloxacin stress and improving the stability of anaerobic digestion systems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for regulating CIP-stressed UASB using physically modified nano-bamboo biochar, in order to solve the above-mentioned defects.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for regulating CIP stress in an upflow anaerobic sludge blanket reactor (UASB) using physically modified nano-bamboo biochar is described, specifically: adding physically modified nano-bamboo biochar, obtained through planetary ball milling, to an upflow anaerobic sludge blanket reactor (UASB) to synergistically regulate the wastewater treatment performance, qepA / qnrB resistance gene abundance, and microbial community structure of the anaerobic digestion system under ciprofloxacin CIP inhibition.

[0008] Preferably, the nano-bamboo biochar is prepared by the following method:

[0009] S1. Dry the raw bamboo shavings, grind them, and then sieve them through a 100-mesh sieve;

[0010] S2. The screened bamboo chips are pyrolyzed in a muffle furnace to obtain bamboo biochar.

[0011] S3. The bamboo biochar obtained in step S2 is ball-milled and physically modified using a planetary ball mill to obtain nano bamboo biochar.

[0012] In step S2, the pyrolysis is specifically performed under the following conditions: in a muffle furnace, the temperature is increased to 600-700℃ at a rate of 10℃ / min, then held at that temperature for 2-3 hours, and finally cooled to room temperature at a rate of 5℃ / min.

[0013] Preferably, in step S3, the ball milling speed of the planetary ball mill is 350-400 r / min, the ball milling time is 5 days, the diameter of the grinding balls is 8, 10 and 15 mm, and the ball-to-powder ratio is 10:1.

[0014] Preferably, the upflow anaerobic sludge blanket reactor (UASB) is cylindrical in shape, with its temperature maintained at 35±5℃, the hydraulic retention time adjusted to 48h by a peristaltic pump, and the influent pH controlled at 7.5-8.0.

[0015] Preferably, the upflow anaerobic sludge blanket reactor (UASB) has a working volume of 5-6L and a nano-bamboo biochar dosage of 5-10g / L.

[0016] Preferably, the influent to the upflow anaerobic sludge blanket reactor (UASB) is synthetic wastewater with a COD content of 4000-5000 mg / L and a carbon-nitrogen-phosphorus ratio of C:N:P = 200:5:1 (where C is the total carbon source in the influent indirectly represented by COD, N is the total Kjeldahl nitrogen, and P is soluble orthophosphate). It contains sucrose (carbon source), ammonium chloride (nitrogen source), potassium dihydrogen phosphate (phosphorus source), and trace elements (iron, manganese, zinc, etc.) required for microbial growth.

[0017] Preferably, the concentration of ciprofloxacin (CIP) in the influent to the upflow anaerobic sludge blanket (UASB) reactor is 10-60 mg / L, simulating the pollution scenario of actual ciprofloxacin-containing wastewater.

[0018] Preferably, one application of the method for regulating CIP stress UASB based on the physically modified nano bamboo biochar is as follows: it is used in an upflow anaerobic sludge blanket reactor (UASB) system under ciprofloxacin CIP stress, and the abundance of methanogenic bacteria of the genera Methanosaeta and Methanosarcina is increased.

[0019] Preferably, when applied to an upflow anaerobic sludge blanket reactor (UASB) system under ciprofloxacin (CIP) stress, it can reduce the effluent ciprofloxacin concentration by 1.5-10 times, and stabilize the COD removal rate at over 96%.

[0020] The beneficial effects of this invention are as follows:

[0021] This invention provides a method for regulating CIP-stressed UASB using physically modified nano-bamboo biochar. This method overcomes the shortcomings of existing technologies, such as low adsorption efficiency of ordinary biochar for ciprofloxacin, weak stress resistance of anaerobic digestion systems, and difficulty in synergistically regulating wastewater treatment performance and environmental risks. It achieves multiple objectives, including efficient treatment of ciprofloxacin-containing wastewater, reduction of the risk of resistance gene accumulation, and stable microbial community structure. Specifically:

[0022] (1) Material innovation and excellent adsorption performance: Nano bamboo biochar is prepared by physical modification of bamboo chips through planetary ball milling. Bamboo chips are widely available and inexpensive. After nano-modification, the specific surface area is greatly increased and the pore structure is more suitable for ciprofloxacin adsorption. This solves the problems of low adsorption capacity and easy desorption of ordinary biochar. It can quickly reduce the concentration of ciprofloxacin in the system and reduce its inhibition on anaerobic microorganisms.

[0023] (2) Synergistic regulation and comprehensive functions: The method of the present invention can not only improve the COD removal rate and methane production of wastewater, but also reduce the abundance of qepA and qnrB resistance genes in a targeted manner, strengthen the dominant position of core methanogenic bacteria of the genus Methanosaeta and Methanosarcina, and achieve synergistic optimization of wastewater treatment performance, resistance gene risk and bacterial community structure, thus making up for the shortcomings of single regulation in the existing technology.

[0024] (3) Process adaptability and strong stability: The method of this invention precisely adapts the nano bamboo biochar to the UASB reactor. By optimizing parameters such as reactor temperature, hydraulic retention time, and influent nutrient ratio, it ensures that the nano biochar is evenly dispersed in the reactor, avoids sedimentation and blockage, and provides a stable growth microenvironment for anaerobic microorganisms, significantly improving the operational stability of the system under ciprofloxacin stress.

[0025] (4) Simple operation and easy to promote: In the method of the present invention, the preparation process of nano bamboo chip biochar is simple, the reactor operating parameters are easy to control, no complex equipment modification is required, the raw material cost is low, and it can be directly applied to the upgrading and transformation of existing anaerobic treatment projects, which has significant engineering application value. Attached Figure Description

[0026] Figure 1 This is a graph showing the cumulative methane production from the batch experiment.

[0027] Figure 2 This is a graph showing the changes in COD concentration in a batch of experiments.

[0028] Figure 3 This is a graph showing the COD removal rate in a batch experiment.

[0029] Figure 4 This is a graph showing the pH changes in a batch of experiments.

[0030] Figure 5 This is a graph showing the concentration of ciprofloxacin at the end of the batch experiment.

[0031] Figure 6 This is a graph showing the change in gas production volume of the UASB reactor.

[0032] Figure 7 This is a graph showing the change in COD concentration in the effluent from the UASB reactor.

[0033] Figure 8 A graph showing the concentration of ciprofloxacin in the effluent from the UASB reactor;

[0034] Figure 9 Abundance diagram of the resistance gene qepA in sludge from a UASB reactor;

[0035] Figure 10 Abundance diagram of the resistance gene qnrB in sludge from a UASB reactor;

[0036] Figure 11 Characteristic diagram of sludge α-diversity (Chao1 index) in UASB reactor;

[0037] Figure 12 β-diversity diagram of sludge from UASB reactor;

[0038] Figure 13 This is a diagram of microbial abundance at the bacterial phylum level in the UASB reactor. Detailed Implementation

[0039] The present invention will be further described below with reference to the embodiments. It should be noted that these are merely examples and descriptions of the inventive concept. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the inventive concept or exceed the scope defined in the claims, they should all be considered to fall within the protection scope of the present invention.

[0040] Example 1: Preparation of Nano-Bamboo Chip Biochar

[0041] This invention relates to a method for physically modifying nano-bamboo biochar to regulate CIP-stressed UASB, wherein the preparation method of the nano-bamboo biochar includes the following steps:

[0042] S1. Take raw biomass bamboo chips, put them in an oven at 105℃ and dry them for 24 hours to remove moisture. Then, grind them in a grinder, pass them through a 100-mesh sieve, and collect the sieve-underfill product for later use.

[0043] S2. Place the screened bamboo chips into a muffle furnace, heat it to 600-700℃ at a rate of 10℃ / min, then keep it at that temperature for 2-3 hours for pyrolysis, and then cool it down to room temperature at a rate of 5℃ / min to obtain bamboo chip biochar.

[0044] S3. Add the bamboo biochar obtained in step S2 into a planetary ball mill, add grinding balls with diameters of 8 mm, 10 mm and 15 mm (ball powder ratio of 10:1), set the ball milling speed to 350-400 r / min and the ball milling time to 5 days, so as to carry out ball milling and physical modification to obtain nano bamboo biochar.

[0045] Example 2: Batch Anaerobic Digestion Experiment

[0046] This invention discloses a method for regulating CIP-stressed UASB using physically modified nano-bamboo biochar. Specifically, for batch anaerobic digestion experiments, the method is based on the physically modified nano-bamboo biochar prepared in Example 1, as detailed below:

[0047] 1. Experimental setup: A 100mL anaerobic flask was used, with a working volume of 75mL. Five experimental groups were set up, with three replicates in each group.

[0048] (1) Blank control group (K): No ciprofloxacin or nano bamboo biochar added;

[0049] (2) Nano bamboo biochar group (K-NBC): 5 g / L nano bamboo biochar was added, but ciprofloxacin was not added;

[0050] (3) Group with only unmilled bamboo biochar (K-BC): 5 g / L of unmilled bamboo biochar was added, without adding ciprofloxacin;

[0051] (4) Ciprofloxacin control group (CIP): 10 mg / L ciprofloxacin was added, but no biochar was added;

[0052] (5) Ciprofloxacin + Nano Bamboo Biochar Group (CIP-NBC): 10 mg / L ciprofloxacin and 5 g / L nano bamboo biochar were added.

[0053] 2. Experimental procedure: Inoculate 1g of anaerobic granular sludge into each anaerobic bottle, add synthetic wastewater (COD=3000mg / L, C:N:P=200:5:1, containing sucrose, ammonium chloride, potassium dihydrogen phosphate and trace elements), purge with nitrogen for 5-10 minutes to create an anaerobic environment, seal and place in a constant temperature reciprocating shaker, set the temperature to 35℃ and the rotation speed to 120rpm for anaerobic digestion.

[0054] 3. Detection indicators and cycle: Samples were taken on days 1, 3, 5, 8, 10, 15, 20, and 25 of the reaction. The COD concentration was determined by high-temperature digestion, the pH value was determined by pH meter, and the ciprofloxacin concentration was determined by liquid chromatography. The volume of gas produced was measured daily by water displacement gas collection method, and the proportion of gas components such as methane and carbon dioxide was determined by gas chromatography.

[0055] 4. Analysis of experimental results:

[0056] (1) Methane production: Figure 1 Figure 1 shows the cumulative methane production in the batch experiments, illustrating the changing trends of cumulative methane production in different experimental groups during anaerobic digestion. As shown in Figure 1, the cumulative methane production in the CIP-NBC group increased by 93% compared to the CIP group, and the K-NBC group increased by 50% compared to the K group, both significantly higher than the K-BC group. This indicates that nano-bamboo biochar can effectively alleviate the inhibition of methanogenic bacteria by ciprofloxacin and improve the gas production performance of anaerobic digestion.

[0057] (2) COD degradation: Figure 2 The graph shows the changes in COD concentration in the wastewater of different experimental groups over time. Figure 3 Figures 2 and 3 show the COD removal rates of different experimental groups in the batch experiments, illustrating the dynamic changes in COD removal rates. As shown in Figures 2 and 3, the initial COD degradation rate of the CIP group was significantly lower than that of other groups. Throughout the entire experimental period, the CIP-NBC group exhibited the best total COD degradation and efficiency, indicating that nano-bamboo biochar can synergistically enhance COD removal through adsorption and the interaction of microbial carriers.

[0058] (3) pH stability: Figure 4Figure 4 shows the pH variation graph of the batch experiments, illustrating the pH stability of the anaerobic digestion system in different experimental groups. As shown in Figure 4, the pH of the K group and the CIP group fluctuated significantly, the pH stability of the K-BC group was between that of the K group and the K-NBC group, and the pH of the CIP-NBC group and the K-NBC group remained stable. This indicates that nano-bamboo biochar can effectively regulate the metabolism of the microbial community and maintain the acid-base balance of the system.

[0059] (4) Removal of ciprofloxacin: Figure 5 Figure 5 shows the ciprofloxacin concentration at the end of the batch experiment, illustrating the removal effect of nano-bamboo biochar on ciprofloxacin. As shown in Figure 5, the ciprofloxacin removal effect of the CIP-NBC group was significantly better than that of the CIP group, confirming that nano-bamboo biochar improves the ciprofloxacin removal efficiency through the synergistic effect of adsorption and biodegradation.

[0060] Example 3: Stable Operation Phase of the UASB Reactor

[0061] This invention discloses a method for regulating CIP stress in a UASB reactor using physically modified nano-bamboo biochar. Specifically, during the stable operation phase of the UASB reactor, the method is based on the physically modified nano-bamboo biochar prepared in Example 1, as detailed below:

[0062] 1. Experimental setup: Three sets of identical upflow anaerobic sludge bed reactors (R1, R2, R3) were built, each with a working volume of 5L. All reactors were equipped with insulation layers to control the temperature at 35±5℃. The hydraulic retention time was adjusted to 48h using peristaltic pumps, and the influent pH was controlled between 7.5 and 8.0.

[0063] 2. Experimental Design:

[0064] R1: Blank control group, no ciprofloxacin wastewater was introduced, and no nano bamboo biochar was added;

[0065] R2: Blank control group, no ciprofloxacin wastewater was introduced, and no nano bamboo biochar was added;

[0066] R3: Nano bamboo biochar group, no ciprofloxacin wastewater is introduced, add 5g / L nano bamboo biochar.

[0067] 3. Operating parameters: Initial influent COD = 4000 mg / L, C:N:P = 200:5:1. After running for 30 days, increase COD to 5000 mg / L and continue running for another 30 days.

[0068] 4. Testing indicators: Regularly sample and measure the COD concentration, gas production, and gas composition of the effluent to ensure stable operation of the reactor.

[0069] 5. Experimental results: After 30 days, the COD removal rate of the three reactors was stable at over 96%. The methane production of the R3 group was about 15% higher than that of the R1 and R2 groups, indicating that the nano bamboo biochar can still improve the anaerobic digestion performance under non-stress conditions, laying a stable foundation for subsequent stress experiments.

[0070] Example 4: Ciprofloxacin stress stage in UASB reactor

[0071] This invention relates to a method for regulating CIP stress in a UASB reactor using physically modified nano-bamboo biochar. Specifically, for the ciprofloxacin stress stage in the UASB reactor, the method is based on the physically modified nano-bamboo biochar prepared in Example 1, as detailed below:

[0072] 1. Experimental setup: The three UASB reactors (R1, R2, R3) from Example 3 were used, and the operating parameters were kept consistent.

[0073] 2. Experimental Design:

[0074] R1: Blank control group, no ciprofloxacin wastewater was introduced, and no nano bamboo biochar was added;

[0075] R2: Ciprofloxacin control group, ciprofloxacin-treated wastewater, no nano bamboo biochar added;

[0076] R3: Ciprofloxacin + Nano Bamboo Chip Biochar Group, with 5-10 g / L of nano bamboo chip biochar added to the ciprofloxacin wastewater.

[0077] 3. Operating parameters: Influent COD=5000mg / L, pH=7.5-8.0, ciprofloxacin concentration gradient set as: 10mg / L (20 days of operation) → 30mg / L (20 days of operation) → 60mg / L (20 days of operation).

[0078] 4. Detection indicators: Regularly sample and measure the effluent COD concentration, ciprofloxacin concentration, pH value, gas production and gas composition. Use real-time PCR to determine the abundance of qepA and qnrB resistance genes in sludge, and use high-throughput sequencing to analyze the microbial community structure.

[0079] 5. Analysis of experimental results:

[0080] (1) Gas production stability: Figure 6 Figure 6 shows the gas production volume change of the UASB reactor, illustrating the gas production stability of the reactor at different operating stages. As shown in Figure 6, with the increase of ciprofloxacin concentration, the gas production of group R2 fluctuated significantly and decreased significantly, while the gas production of group R3 fluctuated slightly but quickly recovered to a stable level and remained higher than that of group R2. This indicates that nano-bamboo biochar can effectively resist high concentrations of ciprofloxacin stress.

[0081] (2) COD removal: Figure 7 The graph shows the COD concentration variation in the effluent from the UASB reactor, illustrating the reactor's continuous COD removal efficiency. Figure 7 As shown, the COD removal rate of group R2 fluctuated significantly under ciprofloxacin stress, and the removal rate decreased significantly at the 60 mg / L concentration stage. The COD removal rate of group R3 remained stable at over 96% for a long period of time, which confirms the high efficiency of this method for treating wastewater containing ciprofloxacin.

[0082] (3) Deep removal of ciprofloxacin: Figure 8 Figure 8 shows the concentration of ciprofloxacin in the effluent of the UASB reactor, illustrating the deep removal effect of nano-bamboo biochar on ciprofloxacin. As shown in Figure 8, on day 80 (10 mg / L CIP stage), the ciprofloxacin concentration in the effluent of group R2 was 10-15 times that of group R3, and on day 100 (30 mg / L CIP stage) and day 120 (60 mg / L CIP stage), it was 1.5-2 times higher, indicating that nano-bamboo biochar has a highly efficient removal effect on ciprofloxacin at different concentrations.

[0083] (4) Resistance gene control: Figure 9 The abundance map of the resistance gene qepA in sludge from the UASB reactor shows the changes in qepA gene abundance in different experimental groups; Figure 10 The abundance diagram of the resistance gene qnrB in sludge from the UASB reactor shows the changes in qnrB gene abundance in different experimental groups. As shown in Figures 9 and 10, the abundance of qepA and qnrB resistance genes in the sludge of group R3 is significantly lower than that in group R2, indicating that nano-bamboo biochar can effectively reduce the risk of resistance gene enrichment.

[0084] (5) Stable microbial community structure: Figure 11 The diagram shows the characteristics of sludge α-diversity (Chao1 index) in the UASB reactor, illustrating the changes in microbial species richness. Figure 12 The β-diversity diagram of sludge from the UASB reactor illustrates the overall stability of the microbial community structure. Figure 13 Figures 11 and 12 show the microbial abundance at the bacterial phylum level in the UASB reactor, illustrating the abundance changes of core methanogens. As shown in Figures 11 and 12, the species richness (Chao1 index) of the R2 group decreased with increasing CIP concentration, and the community structure deviated from the control group. The R3 group had higher community richness and a structure closer to the control group. As shown in Figure 13, the abundance of methanogens *Methanosaeta* and *Methanosarcina* in the R3 group was significantly higher than that in the R2 group, confirming that nano-bamboo biochar can enhance the dominance of core methanogens and maintain the stability of community function.

[0085] This invention provides a method for regulating CIP-stressed UASB using physically modified nano-bamboo biochar. This method overcomes the shortcomings of existing technologies, such as low adsorption efficiency of ordinary biochar for ciprofloxacin, weak stress resistance of anaerobic digestion systems, and difficulty in synergistically regulating wastewater treatment performance and environmental risks. It achieves multiple objectives, including efficient treatment of ciprofloxacin-containing wastewater, reduction of the risk of resistance gene accumulation, and stable microbial community structure. Specifically:

[0086] (1) Material innovation and excellent adsorption performance: Nano bamboo biochar is prepared by physical modification of bamboo chips through planetary ball milling. Bamboo chips are widely available and inexpensive. After nano-modification, the specific surface area is greatly increased and the pore structure is more suitable for ciprofloxacin adsorption. This solves the problems of low adsorption capacity and easy desorption of ordinary biochar. It can quickly reduce the concentration of ciprofloxacin in the system and reduce its inhibition on anaerobic microorganisms.

[0087] (2) Synergistic regulation and comprehensive functions: The method of the present invention can not only improve the COD removal rate and methane production of wastewater, but also reduce the abundance of qepA and qnrB resistance genes in a targeted manner, strengthen the dominant position of core methanogenic bacteria of the genus Methanosaeta and Methanosarcina, and achieve synergistic optimization of wastewater treatment performance, resistance gene risk and bacterial community structure, thus making up for the shortcomings of single regulation in the existing technology.

[0088] (3) Process adaptability and strong stability: The method of this invention precisely adapts the nano bamboo biochar to the UASB reactor. By optimizing parameters such as reactor temperature, hydraulic retention time, and influent nutrient ratio, it ensures that the nano biochar is evenly dispersed in the reactor, avoids sedimentation and blockage, and provides a stable growth microenvironment for anaerobic microorganisms, significantly improving the operational stability of the system under ciprofloxacin stress.

[0089] (4) Simple operation and easy to promote: In the method of the present invention, the preparation process of nano bamboo biochar is simple, the reactor operating parameters are easy to control, no complex equipment modification is required, the raw material cost is low, and it can be directly applied to the upgrading and transformation of existing anaerobic treatment projects, which has significant engineering application value. The method of the present invention is applied to the upflow anaerobic sludge blanket reactor (UASB) system under ciprofloxacin CIP stress, which can increase the abundance of methanogenic bacteria of the genera Methanosaeta and Methanosarcina, and can also reduce the concentration of ciprofloxacin in the effluent by 1.5-10 times, and the COD removal rate is stable at over 96%.

[0090] The above is an exemplary description of the invention. Obviously, the specific implementation of the invention is not limited to the above-described manner. Any non-substantial improvement made using the inventive concept and technical solution of the invention, or the direct application of the inventive concept and technical solution to other situations without modification, is within the protection scope of the invention.

Claims

1. A method for regulating CIP-stressed UASB using physically modified nano-bamboo biochar, characterized in that, Specifically, nano-bamboo biochar, physically modified by planetary ball milling, is added to the upflow anaerobic sludge blanket reactor (UASB) to synergistically regulate the wastewater treatment performance, qepA / qnrB resistance gene abundance, and microbial community structure of the anaerobic digestion system under ciprofloxacin (CIP) inhibition.

2. The method for regulating CIP-stressed UASB using physically modified nano-bamboo biochar according to claim 1, characterized in that, The nano-bamboo shaving biochar is prepared by the following method: S1. Dry the raw bamboo shavings, grind them, and then sieve them through a 100-mesh sieve; S2. The screened bamboo chips are pyrolyzed in a muffle furnace to obtain bamboo biochar. S3. The bamboo biochar obtained in step S2 is ball-milled and physically modified using a planetary ball mill to obtain nano bamboo biochar.

3. The method for regulating CIP-stressed UASB using physically modified nano-bamboo biochar according to claim 2, characterized in that, In step S2, the pyrolysis is specifically performed under the following conditions: in a muffle furnace, the temperature is increased to 600-700℃ at a rate of 10℃ / min, then held at that temperature for 2-3 hours, and finally cooled to room temperature at a rate of 5℃ / min.

4. The method for regulating CIP-stressed UASB using physically modified nano-bamboo biochar according to claim 2, characterized in that, In step S3, the planetary ball mill has a ball milling speed of 350-400 r / min, a ball milling time of 5 days, and grinding ball diameters of 8, 10, and 15 mm, with a ball-to-powder ratio of 10:

1.

5. The method for regulating CIP-stressed UASB using physically modified nano-bamboo biochar according to claim 1, characterized in that, The upflow anaerobic sludge blanket reactor (UASB) maintains a temperature of 35±5℃, adjusts the hydraulic retention time to 48h using a peristaltic pump, and controls the influent pH to 7.5-8.

0.

6. The method for regulating CIP-stressed UASB using physically modified nano-bamboo biochar according to claim 1, characterized in that, The upflow anaerobic sludge blanket reactor (UASB) has a working volume of 5-6L and a nano-bamboo biochar dosage of 5-10g / L.

7. The method for regulating CIP-stressed UASB using physically modified nano-bamboo biochar according to claim 1, characterized in that, The influent to the upflow anaerobic sludge blanket reactor (UASB) is synthetic wastewater with a COD content of 4000-5000 mg / L and a carbon-nitrogen-phosphorus ratio of C:N:P = 200:5:

1. It contains sucrose, ammonium chloride, potassium dihydrogen phosphate, and trace elements.

8. The method for regulating CIP-stressed UASB using physically modified nano-bamboo biochar according to claim 1, characterized in that, The concentration of ciprofloxacin (CIP) in the influent of the upflow anaerobic sludge blanket reactor (UASB) is 10-60 mg / L.

9. An application characterized in that, The method for regulating CIP stress in an upflow anaerobic sludge blanket reactor (UASB) based on any one of claims 1-8 is specifically used in an upflow anaerobic sludge blanket reactor (UASB) system under ciprofloxacin CIP stress, and to increase the abundance of methanogenic bacteria of the genera *Methanosaeta* and *Methanosarcina*.

10. The application according to claim 9, characterized in that, When applied to an upflow anaerobic sludge blanket reactor (UASB) system under ciprofloxacin (CIP) stress, it can reduce the effluent ciprofloxacin concentration by 1.5-10 times, and maintain a COD removal rate of over 96%.

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