Sludge anaerobic removal of resistance gene regulation method

Abstract

The application discloses a sludge anaerobic resistance gene removal method and belongs to the technical field of sludge harmless resource treatment. The sludge is subjected to ultrasonic-biological surfactant composite pretreatment to break sludge floc and drug-resistant bacteria cells and fully release hidden resistance genes. A stable anaerobic reaction environment is constructed by optimizing an anaerobic inoculation system, and modified zero-valent iron, nanofiber fillers and a quorum sensing inhibitor composite agent are added in a gradient mode to remove the resistance genes in multiple dimensions from the aspects of nucleic acid degradation, adsorption fixation and horizontal transfer blocking. The application solves the technical problems that the resistance genes are not completely removed in the traditional sludge anaerobic process, are easily spread and cannot be simultaneously treated in a harmless and resourceful manner, and significantly improves sludge reduction and biogas yield. The process is stable, green and free of secondary pollution, is suitable for the large-scale harmless treatment and resource utilization of various municipal and industrial sludge and has a wide engineering application prospect.

Description

Technical Field

[0001] This invention relates to the field of sludge resource utilization and environmental microbial pollution control technology, and in particular to a method for regulating sludge anaerobic removal resistance genes. Background Technology

[0002] With the acceleration of urbanization and the rapid development of the wastewater treatment industry, the output of residual sludge from municipal wastewater treatment plants has been increasing year by year. The harmless, reduced-volume, and resource-based disposal of sludge has become a key challenge in ecological and environmental governance. During wastewater treatment, antibiotics, drug-resistant bacteria, and resistance genes in water bodies accumulate in large quantities in the residual sludge, making it an important reservoir and carrier of antibiotic resistance genes (ARGs) in the environment. Resistance genes can spread widely in soil, water bodies, and microbial communities through horizontal gene transfer and bacterial diffusion, inducing drug resistance in environmental microorganisms. This poses a significant threat to ecological and environmental safety and human health, and has become a research hotspot for the prevention and control of emerging pollutants.

[0003] Anaerobic digestion technology is currently the mainstream process for the resource utilization of sludge, combining the advantages of sludge reduction, stabilization, and biomass energy recovery, enabling the degradation of organic matter and the resource utilization of methane in sludge. However, traditional anaerobic digestion processes for sludge have significant technical shortcomings. Conventional mesophilic and thermophilic anaerobic digestion can only inactivate some drug-resistant bacteria, with limited effectiveness in removing intracellular and extracellular resistance genes in sludge. Furthermore, when the microbial community structure of the anaerobic system is unbalanced and metabolically disordered, it can exacerbate the horizontal transfer of resistance genes, resulting in high levels of resistance genes remaining in the digested sludge and biogas slurry. At the same time, traditional processes lack targeted resistance gene regulation mechanisms and cannot accurately inhibit the diffusion of resistance genes mediated by mobile genetic elements. Therefore, there are still extremely high ecological risks during the land application of treated sludge and the reuse of biogas slurry, severely restricting the widespread application of sludge resource utilization.

[0004] In existing technologies, some studies have enhanced the removal of resistance genes through physical pretreatment, exogenous reagent addition, and temperature control. However, these methods generally suffer from problems such as single-mode regulation, poor adaptability, unstable removal efficiency, and easy disruption of the anaerobic methanogenic system balance. For example, single ultrasonic pretreatment can only break down sludge microbial cells and cannot degrade free resistance genes, easily leading to secondary release of resistance genes; single temperature control is energy-intensive, and high-temperature conditions can easily lead to the loss of functional microorganisms, affecting anaerobic digestion efficiency; conventional metal reagents and biological agents lack precise concentration control, and excessive addition will inhibit the activity of anaerobic microorganisms and reduce methane yield, while insufficient addition cannot effectively block the spread of resistance genes. In addition, existing technologies have not established a linkage regulation mechanism between the anaerobic system microbial community structure, physicochemical parameters, and resistance gene abundance, and cannot achieve a synergistic unity between improving anaerobic digestion efficiency and efficient removal of resistance genes, resulting in poor technical practicality and engineering adaptability.

[0005] To address the aforementioned shortcomings of existing technologies, this invention proposes a precise, controllable, efficient, and stable method for regulating the anaerobic removal of resistance genes in sludge, which balances sludge resource utilization with the harmlessness of resistance genes. This method solves the technical problems of low resistance gene removal rate, easy secondary propagation, anaerobic system imbalance, and poor engineering adaptability in traditional processes. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing anaerobic sludge treatment technologies, such as incomplete removal of resistance genes, easy horizontal transmission, lack of synergy between anaerobic digestion performance and resistance gene control, and low precision in process control. This invention provides a method for regulating the anaerobic removal of resistance genes in sludge. Through an integrated regulatory system encompassing pretreatment modification, precise dosing of compound functional agents, coordinated regulation of anaerobic environmental parameters, and targeted optimization of microbial community structure, this invention efficiently degrades intracellular and extracellular resistance genes in sludge, blocks horizontal transfer pathways of resistance genes, and simultaneously stabilizes the anaerobic digestion microbial system. This ensures efficient sludge reduction and methane resource utilization, achieving a dual improvement in sludge harmlessness and resource utilization.

[0007] A method for regulating resistance genes in anaerobic sludge removal includes the following steps: S1. Sludge pretreatment and modification: Take the remaining sludge to be treated, screen to remove large particulate impurities, and adjust the sludge solids content to 8%~12% to obtain homogeneous sludge; use ultrasonic-biosurfactant composite pretreatment to treat the homogeneous sludge, first perform low-frequency ultrasonic crushing, then add rhamnolipid and stir at a constant temperature to modify it, break up sludge flocs and drug-resistant bacterial cells, and release intracellular resistance genes; S2. Adaptation of anaerobic inoculation system: The pretreated sludge is put into a closed anaerobic digestion reactor. The acclimated anaerobic inoculation sludge is added at a volume ratio of sludge to anaerobic inoculation sludge of 3:1 to 5:1. After mixing evenly, nitrogen gas is introduced to purge the reactor to maintain an absolutely anaerobic environment and adjust the initial pH and redox potential of the system. S3. Precise regulation with compound functional agents: Based on the initial abundance of resistance genes in the sludge, compound regulatory agents are added in three stages in a gradient. The compound regulatory agents include modified zero-valent iron, nitrogen-doped nanofiber fillers, and quorum sensing inhibitors. Targeted regulation is achieved by degrading resistance genes, blocking horizontal transfer, and optimizing the microbial community structure. S4. Anaerobic environmental parameter linkage control: adopts a segmented temperature control and pH and ORP linkage control mode, sets differentiated operating parameters for the acid production stage, methanogenesis stage and stable degradation stage, monitors system indicators in real time and makes dynamic fine adjustments to maintain anaerobic metabolic balance. S5. Post-treatment stabilization and solidification: After the anaerobic digestion cycle is completed, the sludge is allowed to stand at low temperature to solidify, degrade residual resistance genes, block the secondary diffusion of resistance genes, and obtain harmless and stable sludge.

[0008] Further, in step S1, the low-frequency ultrasonic fragmentation parameters are: ultrasonic frequency 25~35kHz, ultrasonic power 180~220W, and ultrasonic time 8~12min; the rhamnolipin dosage is 0.15~0.25g / gSS, the modification temperature is 30~35℃, the stirring speed is 120~150r / min, and the stirring time is 20~30min; the pretreated sludge floc fragmentation rate is ≥85%, and the intracellular resistance gene release rate is ≥75%.

[0009] Furthermore, in step S2, the nitrogen purging time is 8~12 min, the purging flow rate is 0.8~1.2 L / min, and the oxygen content in the reactor is ≤0.5%; the initial pH of the system is adjusted to 6.8~7.2, and the initial ORP is controlled at -320~-280mV.

[0010] Further, in step S3, the mass ratio of each component of the composite regulatory agent is as follows: 60%~70% modified zero-valent iron, 20%~25% nitrogen-doped nanofiber filler, and 5%~10% quorum sensing inhibitor; the modified zero-valent iron is micron-sized zero-valent iron activated by dilute hydrochloric acid with a particle size of 20~50μm; the nitrogen-doped nanofiber filler has a specific surface area ≥120m² / g; and the quorum sensing inhibitor is an N-acetylhomoserine lactone antagonist.

[0011] Furthermore, in step S3, the total dosage of the compound regulating agent is 0.8~1.5g / g dry weight of sludge, and it is added in three stages: 40% of the total dosage is added from 0 to 3 days, 35% of the total dosage is added from 4 to 10 days, and 25% of the total dosage is added from 11 to 20 days.

[0012] Furthermore, in step S4, the segmented parameter control specifically involves: Acid production stage 0~5d: temperature control 32~35℃, pH 6.5~6.8, ORP -300~-260mV, stirring every 4 hours for 5 minutes each time, stirring speed 80r / min; Methanogenesis stage 6~18d: temperature control 38~42℃, pH 7.0~7.5, ORP -350~-320mV, stirring every 6h for 8min, stirring speed 60r / min; Stable degradation phase 19~25 days: temperature controlled at 35~38℃, pH 6.8~7.2, ORP -330~-300mV, static culture without stirring.

[0013] Furthermore, in step S4, the abundance of sludge resistance genes, the concentration of volatile fatty acids, and the daily methane production are monitored daily. When the concentration of volatile fatty acids exceeds 500 mg / L, the stirring frequency is reduced and the pH is slightly increased. When the degradation rate of resistance genes is less than 5% / d, a small amount of compound regulatory agent is added.

[0014] Furthermore, in step S5, the low-temperature static solidification temperature is 20~25℃, and the static time is 24~36h to maintain a micro-anaerobic environment, thereby achieving the degradation of residual resistance genes and solidification of sludge structure.

[0015] The beneficial effects of this invention are as follows: 1. High efficiency in removing resistance genes: This invention achieves high removal rates by simultaneously and efficiently removing intracellular, extracellular, and floc-adsorbed resistance genes from sludge through multi-level regulation, including pretreatment to break down cells and release genes, targeted degradation by compound agents, blocking of horizontal transfer pathways, and post-solidification to inhibit diffusion.

[0016] 2. Achieving synergistic unity of resource utilization and harmlessness: The segmented environmental parameter regulation of this invention can accurately adapt to the metabolic patterns of anaerobic microorganisms. The compound agent not only has the function of degrading resistance genes, but also optimizes the structure of anaerobic bacteria, and improves the degradation rate of sludge organic matter and the methane production rate.

[0017] 3. Green and energy-saving process with good engineering adaptability: This invention uses biosurfactants and nano-composite environmentally friendly agents, which have no secondary pollution. The overall process is simple to operate and the equipment is highly adaptable. It can be directly adapted to the transformation of existing municipal sludge anaerobic digestion projects, with low cost and strong practicality. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0020] 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. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] A method for regulating resistance genes in anaerobic sludge removal includes the following steps: S1. Sludge pretreatment and modification: Take the remaining sludge to be treated, and first remove large particulate impurities such as sand and fiber from the sludge by mechanical screening. Adjust the sludge solids content to 8%~12% to obtain homogeneous sludge. Modify the homogeneous sludge by ultrasonic-biosurfactant composite pretreatment. First, perform low-frequency ultrasonic crushing treatment, and then add rhamnolipin biosurfactant for constant temperature stirring modification to destroy the sludge floc structure and drug-resistant bacterial cell membrane, release intracellular resistance genes, and at the same time weaken the binding force between resistance genes and sludge colloids. The low-frequency ultrasonic crushing parameters are: ultrasonic frequency 25~35kHz, ultrasonic power 180~220W, ultrasonic treatment time 8~12min; rhamnolipin dosage is 0.15~0.25g / gSS, modification temperature 30~35℃, stirring speed 120~150r / min, stirring time 20~30min.

[0022] After pretreatment, the sludge floc breaking rate was ≥85%, the intracellular resistance gene release rate was ≥75%, and the soluble protein and soluble polysaccharide dissolution of sludge were significantly increased, providing basic conditions for subsequent resistance gene degradation and anaerobic microbial metabolism.

[0023] S2. Anaerobic inoculation system adaptation: The pretreated sludge is put into a closed anaerobic digestion reactor. The acclimated anaerobic inoculation sludge is added at a sludge to anaerobic inoculation sludge volume ratio of 3:1 to 5:1. The anaerobic inoculation sludge is activated sludge that has been stably operating in the municipal sludge anaerobic digestion reactor for more than 60 days. Before inoculation, the activity of the inoculation sludge microbial community is tested to ensure that the abundance of acid-producing bacteria and methanogenic bacteria meets the standards. After stirring and mixing evenly, high-purity nitrogen gas is introduced to purge the air inside the reactor to maintain an absolutely anaerobic environment in the reactor. Nitrogen purging time is 8~12 min, purging flow rate is 0.8~1.2 L / min, and the oxygen content in the reactor is ≤0.5%; after mixing, the initial pH of the sludge system is adjusted to 6.8~7.2, and the initial ORP is controlled at -320~-280mV.

[0024] S3. Precise regulation with compound functional agents: Based on the initial total abundance of resistance genes in the sludge, compound regulatory agents are added in stages and gradients. The compound regulatory agents include modified zero-valent iron, nitrogen-doped nanofiber fillers and quorum sensing inhibitors. Through the triple action of oxidative degradation, adsorption and fixation and microbial community regulation, the free resistance genes are degraded, the horizontal transfer of resistance genes is inhibited, and the anaerobic functional microbial community structure is optimized in a targeted manner. The mass ratio of each component in the composite regulatory agent is as follows: 60%~70% modified zero-valent iron, 20%~25% nitrogen-doped nanofiber filler, and 5%~10% quorum sensing inhibitor. The modified zero-valent iron is micron-sized zero-valent iron with a particle size of 20~50μm, which is activated by dilute hydrochloric acid and loaded with iron oxide on its surface. The nitrogen-doped nanofiber filler is prepared by electrospinning-high temperature sintering process and has a specific surface area ≥120m² / g. The quorum sensing inhibitor is an N-acetylhomoserine lactone antagonist.

[0025] The agent is added in three stages: in the first stage (0-3 days of anaerobic digestion), 40% of the total agent is added to rapidly degrade free resistance genes and break down residual drug-resistant bacteria; in the second stage (4-10 days of anaerobic digestion), 35% of the total agent is added to inhibit the activity of mobile genetic elements and block the horizontal transfer of resistance genes; in the third stage (11-20 days of anaerobic digestion), 25% of the total agent is added to stabilize the bacterial community structure and continuously degrade residual resistance genes; the total dosage of the compound regulatory agent is 0.8-1.5 g / g dry weight of sludge.

[0026] S4. Anaerobic environmental parameter linkage control: A segmented temperature control and pH and oxidation-reduction potential (ORP) linkage control mode is adopted. Different operating parameters are set for the early acid production stage, the middle methanogenesis stage, and the later stable degradation stage. The SCOD of sludge, volatile fatty acids, methane production and resistance gene abundance in the reactor are monitored simultaneously. The operating parameters are dynamically fine-tuned to maintain the metabolic balance of the anaerobic system. The segmented parameter control is specifically as follows: 1) Acid production stage (0~5d): Temperature control 32~35℃, pH maintenance 6.5~6.8, ORP maintenance -300~-260mV, stirring interval 4h / time, stirring for 5min each time, stirring speed 80r / min, to promote the hydrolysis of organic matter in sludge to produce acid and provide substrate for methanogenic bacteria; 2) Methanogenic stage (6~18d): Temperature control 38~42℃, pH maintained 7.0~7.5, ORP maintained -350~-320mV, stirring interval 6h / time, stirring for 8min each time, stirring speed 60r / min, to optimize the metabolic activity of methanogenic bacteria and ensure biogas production rate. 3) Stable degradation stage (19~25d): Temperature controlled at 35~38℃, pH maintained at 6.8~7.2, ORP maintained at -330~-300mV, stirring stopped, static culture, and continuous degradation of trace residual resistance genes.

[0027] The total abundance of sludge resistance genes, volatile fatty acid concentration, and daily methane production in the reactor are monitored daily. When the volatile fatty acid concentration exceeds 500 mg / L, the stirring frequency is reduced and the pH is slightly increased. When the degradation rate of resistance genes is less than 5% / day, a small amount of compound regulating agent is added to ensure stable degradation efficiency.

[0028] S5. Post-stabilization and solidification treatment: After the anaerobic digestion cycle is completed, the sludge in the reactor is subjected to low-temperature static solidification treatment to simultaneously degrade residual trace resistance genes, fix residual microorganisms in the sludge, block the subsequent diffusion of resistance genes, and finally obtain harmless stabilized sludge and qualified biogas liquid.

[0029] The low-temperature static solidification temperature is 20~25℃, and the static time is 24~36h. During the static process, a micro-anaerobic environment is maintained, and residual resistance genes are further degraded through the endogenous respiration of microorganisms. At the same time, it promotes the stable solidification of sludge microbial flocs and inhibits the recovery of bacteria and the secondary diffusion of resistance genes.

[0030] Working principle: This invention employs an integrated regulatory logic of "pretreatment to disrupt cells and release genes - targeted degradation by compound agents - environmental parameter-linked bacterial control - post-solidification to inhibit diffusion," comprehensively achieving efficient removal and risk control of sludge resistance genes. First, through ultrasonic-biosurfactant composite pretreatment, the dense floc structure of the sludge and the cell walls and membranes of drug-resistant bacteria are broken down, fully releasing the intracellularly encapsulated and floc-adsorbed resistance genes into the liquid phase system, solving the problem of hidden and difficult-to-degrade resistance genes in traditional anaerobic treatment. Second, modified zero-valent iron in the compound regulatory agent can destroy the nucleic acid structure of resistance genes through reduction-oxidation reactions, directly degrading free resistance genes while removing residual antibiotics from the system and eliminating the substrate conditions for resistance gene induction expression. Nitrogen-doped nanofiber packing material, with its high specific surface area, achieves adsorption and fixation of resistance genes and drug-resistant bacteria, enriching functional microorganisms and optimizing the anaerobic microenvironment. Quorum sensing inhibitors can block microbial quorum sensing pathways, inhibiting gene transfer behaviors at the bacterial conjugation and transduction levels, preventing the spread of resistance genes from the root.

[0031] Meanwhile, this invention precisely matches the microbial metabolic needs at different stages of anaerobic digestion through segmented anaerobic environmental parameter linkage control. In the early stage, it promotes organic matter hydrolysis and acid production; in the middle stage, it enhances the activity of methanogenic bacteria to ensure sludge resource utilization efficiency; in the later stage, it stabilizes the system environment and continuously degrades trace resistance genes, solving the problem of imbalance between resistance gene removal and anaerobic methanogenesis performance in traditional processes. Finally, through low-temperature static solidification treatment, residual drug-resistant microorganisms are further inactivated, the sludge structure is solidified, and the risk of secondary release and spread of resistance genes is completely eliminated, achieving the synergistic treatment of sludge harmlessness, stabilization, and resource utilization. Example 1

[0032] This embodiment provides a method for regulating anaerobic sludge removal resistance genes, used to treat excess sludge from the secondary sedimentation tank of a municipal wastewater treatment plant. The specific steps are as follows: S1. Sludge pretreatment and modification: Fresh excess sludge was taken and screened through a 20-mesh sieve to remove impurities. The sludge solids content was adjusted to 10% to obtain homogeneous sludge. Ultrasonic-rhamnolipin composite pretreatment was performed with an ultrasonic frequency of 30kHz, an ultrasonic power of 200W, and ultrasonic treatment for 10 minutes. Then, 0.2g / gSS of rhamnolipin was added, and the mixture was stirred at a constant temperature of 32℃ and 130r / min for 25 minutes. After pretreatment, the sludge floc breaking rate was 88%, and the intracellular resistance gene release rate was 78%.

[0033] S2. Anaerobic inoculation system adaptation: The pretreated sludge is put into a closed anaerobic reactor, and the acclimated anaerobic inoculation sludge is added at a volume ratio of 4:1. After mixing evenly, high-purity nitrogen gas is purged for 10 minutes at a flow rate of 1.0 L / min. The oxygen content in the reactor is ≤0.5%. The initial pH of the system is adjusted to 7.0 and ORP to 300 mV.

[0034] S3. Precise regulation with composite functional agents: The mass ratio of each component of the composite regulatory agent is 65% modified zero-valent iron, 28% nitrogen-doped nanofiber filler, and 7% quorum sensing inhibitor, with a total dosage of 1.2g / g dry weight of sludge; it is added in three stages: 40% for 0~3d, 35% for 4~10d, and 25% for 11~20d.

[0035] S4. Anaerobic environmental parameter linkage control: 0~5d acid production stage, temperature controlled at 33℃, pH 6.6, ORP -280mV, stirring every 4 hours for 5 minutes each time, rotation speed 80r / min; 6~18d methanogenesis stage, temperature controlled at 40℃, pH 7.2, ORP -330mV, stirring every 6 hours for 8 minutes each time, rotation speed 60r / min; 19~25d stable degradation stage, temperature controlled at 36℃, pH 7.0, ORP -310mV, static culture; daily monitoring of indicators, dynamic fine-tuning of parameters.

[0036] S5. Post-stabilization and solidification treatment: After 25 days of anaerobic digestion, the sludge is left to stand at 22℃ for 30 hours to complete the solidification of sludge and degradation of residual resistance genes. Example 2

[0037] This embodiment provides a method for regulating resistance genes in anaerobic sludge removal, used to treat integrated biochemical sludge from industrial parks. The specific steps are as follows: S1. Sludge pretreatment and modification: Industrial biochemical sludge was sieved through a 20-mesh screen to remove impurities and the solid content was adjusted to 9%. Ultrasonic pretreatment parameters: 28kHz, 190W, 9min. 0.18g / gSS rhamnolipid was added and stirred at 31℃ and 120r / min for 22min. The sludge floc breaking rate was 86% and the intracellular resistance gene release rate was 76%.

[0038] S2, Anaerobic Inoculation System Adaptation: Sludge to Inoculated Sludge Volume Ratio 3:1, Nitrogen Purging for 9 min, Flow Rate 0.9 L / min, Controlled Oxygen Content ≤0.5%, Initial pH 6.9, ORP -290 mV.

[0039] S3. Precise control of compound functional agents: The compound agent ratio is 68% modified zero-valent iron, 25% nitrogen-doped nanofiber filler, and 7% quorum sensing inhibitor, with a total dosage of 1.0 g / g dry weight of sludge. It is added in three stages with gradient, and the dosage ratio is the same as in Example 1.

[0040] S4. Anaerobic environmental parameter linkage control: segmented temperature control, pH, and ORP parameters are matched to the metabolic characteristics of industrial sludge. The acidification stage is 32℃, pH 6.5, and ORP -270mV; the methanogenesis stage is 39℃, pH 7.3, and ORP -340mV; and the stabilization stage is 35℃, pH 6.9, and ORP -320mV. The stirring regime is the same as in Example 1.

[0041] S5. Post-treatment stabilization and curing: Let stand at 21℃ for 28 hours to complete the harmless curing process.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for regulating resistance genes in anaerobic sludge removal, characterized in that, Includes the following steps: S1. Sludge pretreatment and modification: Take the remaining sludge to be treated, screen to remove large particulate impurities, and adjust the sludge solids content to 8%~12% to obtain homogeneous sludge; use ultrasonic-biosurfactant composite pretreatment to treat the homogeneous sludge, first perform low-frequency ultrasonic crushing, then add rhamnolipid and stir at a constant temperature to modify it, break up sludge flocs and drug-resistant bacterial cells, and release intracellular resistance genes; S2. Adaptation of anaerobic inoculation system: The pretreated sludge is put into a closed anaerobic digestion reactor. The acclimated anaerobic inoculation sludge is added at a volume ratio of sludge to anaerobic inoculation sludge of 3:1 to 5:

1. After mixing evenly, nitrogen gas is introduced to purge the reactor to maintain an absolutely anaerobic environment and adjust the initial pH and redox potential of the system. S3. Precise regulation with compound functional agents: Based on the initial abundance of resistance genes in the sludge, compound regulatory agents are added in three stages in a gradient. The compound regulatory agents include modified zero-valent iron, nitrogen-doped nanofiber fillers, and quorum sensing inhibitors. Targeted regulation is achieved by degrading resistance genes, blocking horizontal transfer, and optimizing the microbial community structure. S4. Anaerobic environmental parameter linkage control: adopts a segmented temperature control and pH and ORP linkage control mode, sets differentiated operating parameters for the acid production stage, methanogenesis stage and stable degradation stage, monitors system indicators in real time and makes dynamic fine adjustments to maintain anaerobic metabolic balance. S5. Post-treatment stabilization and solidification: After the anaerobic digestion cycle is completed, the sludge is allowed to stand at low temperature to solidify, degrade residual resistance genes, block the secondary diffusion of resistance genes, and obtain harmless and stable sludge.

2. The method for regulating anaerobic removal resistance genes in sludge according to claim 1, characterized in that, In step S1, the low-frequency ultrasonic fragmentation parameters are: ultrasonic frequency 25~35kHz, ultrasonic power 180~220W, and ultrasonic time 8~12min; the rhamnolipin dosage is 0.15~0.25g / gSS, the modification temperature is 30~35℃, the stirring speed is 120~150r / min, and the stirring time is 20~30min; the pretreated sludge floc fragmentation rate is ≥85%, and the intracellular resistance gene release rate is ≥75%.

3. The method for regulating anaerobic removal resistance genes in sludge according to claim 1, characterized in that, In step S2, the nitrogen purging time is 8~12 min, the purging flow rate is 0.8~1.2 L / min, and the oxygen content in the reactor is ≤0.5%; the initial pH of the system is adjusted to 6.8~7.2, and the initial ORP is controlled at -320~-280mV.

4. The method for regulating anaerobic removal resistance genes in sludge according to claim 1, characterized in that, In step S3, the mass ratio of each component of the composite regulatory agent is as follows: 60%~70% modified zero-valent iron, 20%~25% nitrogen-doped nanofiber filler, and 5%~10% quorum sensing inhibitor; the modified zero-valent iron is micron-sized zero-valent iron activated by dilute hydrochloric acid with a particle size of 20~50μm; the nitrogen-doped nanofiber filler has a specific surface area ≥120m² / g; and the quorum sensing inhibitor is an N-acetylhomoserine lactone antagonist.

5. The method for regulating anaerobic removal resistance genes in sludge according to claim 1, characterized in that, In step S3, the total dosage of the compound regulating agent is 0.8~1.5g / g dry weight of sludge, and it is added in three stages: 40% of the total dosage is added from 0 to 3 days, 35% of the total dosage is added from 4 to 10 days, and 25% of the total dosage is added from 11 to 20 days.

6. The method for regulating anaerobic removal resistance genes in sludge according to claim 1, characterized in that, In step S4, the segmented parameter control is specifically as follows: Acid production stage 0~5d: temperature control 32~35℃, pH 6.5~6.8, ORP -300~-260mV, stirring every 4 hours for 5 minutes each time, stirring speed 80r / min; Methanogenesis stage 6~18d: temperature control 38~42℃, pH 7.0~7.5, ORP -350~-320mV, stirring every 6h for 8min, stirring speed 60r / min; Stable degradation phase 19~25 days: temperature controlled at 35~38℃, pH 6.8~7.2, ORP -330~-300mV, static culture without stirring.

7. The method for regulating anaerobic removal resistance genes in sludge according to claim 1, characterized in that, In step S4, the abundance of sludge resistance genes, the concentration of volatile fatty acids, and the daily methane production are monitored daily. When the concentration of volatile fatty acids exceeds 500 mg / L, the stirring frequency is reduced and the pH is slightly increased. When the degradation rate of resistance genes is less than 5% / d, a small amount of compound regulatory agent is added.

8. The method for regulating anaerobic removal resistance genes in sludge according to claim 1, characterized in that, In step S5, the low-temperature static solidification temperature is 20~25℃, and the static time is 24~36h to maintain a micro-anaerobic environment and achieve the degradation of residual resistance genes and solidification of sludge structure.

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