Microbial degradation treatment method for organic pollutants in a watershed

Abstract

The present application relates to the technical field of water treatment, and discloses a method for degrading and treating organic pollutants in a drainage basin, comprising: introducing drainage basin sewage with fluctuating flow and load, using a preset flow pattern of a flow distribution member to distribute the drainage basin sewage into a degradation flow direction and an overload flow direction, guiding the degradation flow direction to contact a multistage anaerobic biofilm attached to the surface of the filler to generate a degradation reaction, the preset flow pattern having a geometric interface that adjusts the flow area according to the water level, when the flow exceeds the preset load limit, a flow distribution ratio that increases nonlinearly with the rising water level is generated, so that the internal flow field shear stress of the main degradation zone is maintained within the adhesion strength threshold of the multistage anaerobic biofilm, the present application uses a physical pattern to preset the hydraulic distribution rule, ensures the adhesion stability of the biological community under the impact of runoff, and maintains the degradation activity of the system in a variable working condition environment.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and more specifically to a method for the microbial degradation of organic pollutants in watersheds. Background Technology

[0002] Currently, in the field of organic pollutant treatment in watersheds in hilly areas of southern China, the technology of coupling anaerobic biofilters with constructed wetlands is adopted. By attaching microbial biofilms to the surface of the packing material to reduce organic substrates through their metabolic activity, it has the advantages of low operating costs and good ecological compatibility. However, due to the large slope of the hilly terrain and the highly concentrated seasonal rainfall, the inflow of watersheds exhibits drastic nonlinear fluctuations during periods of heavy rainfall. Such sudden hydraulic shocks not only shorten the contact time between organic substrates and biofilms, but also generate instantaneous high shear forces that can lead to a large-scale loss of microbial populations inside the biofilter.

[0003] Existing technologies mitigate impact by optimizing interception well structures, but the physical distribution structure is rigid, and there is a logical mismatch between the diversion function and the nonlinear threshold of biofilm peeling. This makes it impossible to match the nonlinear degradation trend of adhesion force as the flow velocity increases. When the hardware configuration cannot take into account the water distribution accuracy, the external control logic is constrained by the objective environment. For example, Chinese utility model patent with authorization announcement number CN222332907U discloses a sewage pipe network interception device that uses a flow monitor signal to drive an electric gate to adjust the opening. This active control scheme has defects: the initial runoff of sewage in the watershed carries silt and floating matter, which can easily cause precision sensors to fail or the signal to drift, resulting in adjustment lag; the scheme relies on power supply and operation and maintenance, making it difficult to adapt to remote and decentralized passive non-point source pollution treatment scenarios; the linear adjustment logic based on the overall flow cannot accurately anchor the surface dynamic boundary of microbial extracellular polymers affected by the flow field shear stress, making it difficult for the system to balance ensuring the total amount of sewage intercepted and maintaining biofilm stability.

[0004] Therefore, the technical problem to be solved by this invention is how to solidify the laws of microbial metabolism and nonlinear fluid dynamics through spatial geometry, and construct a flow field configuration with passive adaptive scheduling capability under no-energy-driven conditions, so as to eliminate the risk of biofilm peeling under fluctuating conditions and improve degradation efficiency. Summary of the Invention

[0005] This invention proposes a method for the microbial degradation of organic pollutants in watersheds, comprising the following steps:

[0006] Step S1: Introduce wastewater from the watershed. The wastewater in the watershed exhibits fluctuations in influent flow and organic load due to rainfall and runoff.

[0007] Step S2: The wastewater in the basin is physically divided into two streams by using the pre-set flow morphology of the diversion component: the wastewater in the basin is divided into a degradation flow direction that enters the main degradation zone and an overload flow direction that bypasses the main degradation zone.

[0008] Step S3 guides the degradation flow into the main degradation zone, where it contacts the multi-stage anaerobic biofilm attached to the packing surface and generates a biochemical degradation reaction. The pre-set flow morphology has a geometric interface with a cross-sectional area that adjusts with water level, and this interface possesses flow damping characteristics preset based on microbial metabolic parameters. When the influent flow rate of the wastewater exceeds the preset load limit of the main degradation zone, the pre-set flow morphology, through the physical morphology adjustment of the geometric interface, generates a non-linearly increasing split ratio that rises with water level. This cuts the wastewater exceeding the preset load limit into the overload flow direction, maintaining the flow field shear stress within the main degradation zone within a preset shear stress range lower than the critical adhesion strength of the extracellular polymers of the multi-stage anaerobic biofilm. This stabilizes the attachment structure of the multi-stage anaerobic biofilm and reduces microbial loss.

[0009] Preferably, during the low-flow interval after rainfall, the structural damping characteristics of the pre-set flow morphology are used to reduce the flow velocity in the main degradation zone, thereby extending the hydraulic retention time of the wastewater in the main degradation zone. During the extended hydraulic retention time, the main degradation zone utilizes residual nutrients to induce a population reconstruction response in the damaged microbial community, thereby restoring the main degradation zone to its rated degradation flux.

[0010] Preferably, the multi-stage anaerobic biofilm is constructed through a graded acclimatization process, which includes: in the early stage of biofilm formation, a low shear force flow field of 0.05 m / s to 0.15 m / s is used to induce the initial bacterial community to attach; during the biofilm maturation period, the shear force of the flow field is gradually increased to between 0.5 Pa and 1.2 Pa in order to screen for dominant bacterial communities with extracellular polymer secretion characteristics.

[0011] Preferably, the split ratio defined by the preset flow profile follows the following quantitative constraint rules: ,in, The flow splitting ratio is the overload flow direction, k is the gain coefficient determined by the geometric parameters of the flow splitting component, and h is the real-time water level height within the flow splitting component. The critical water level threshold that triggers the diversion is denoted as m, which is a nonlinear exponent characterizing the flow field cutting characteristics and m>1.

[0012] Preferably, the pre-set flow profile is achieved by setting a cutting edge with a specific geometric curvature at the diversion interface. The radius of curvature of the cutting edge is configured according to the flow cross-sectional area and Reynolds number distribution of the main degradation zone at different water levels, so as to eliminate hydraulic oscillations inside the main degradation zone when the influent flow rate changes abruptly.

[0013] Preferably, the main degradation zone is provided with a honeycomb packing skeleton, and the multi-stage anaerobic biofilm is attached to the inner wall of the honeycomb packing skeleton; the pore size distribution of the honeycomb packing skeleton matches the flow distribution characteristics of the pre-set flow morphology, ensuring that the local shear stress on the inner wall does not exceed 1.5 Pa when the flow distribution ratio is at its maximum.

[0014] Preferably, the biochemical degradation reaction in step S3 is used to synergistically degrade chemical oxygen demand, total nitrogen and total phosphorus in the wastewater of the watershed; the multi-stage anaerobic biofilm forms anaerobic gradient, anoxic gradient and microaerobic gradient distributed along the water flow direction in the main degradation zone, so as to achieve the simultaneous completion of organic matter degradation and nitrogen and phosphorus removal.

[0015] Preferably, the overload flow generated in step S2 is guided into an ecological retention ditch or artificial wetland for end-of-pipe interception, in order to intercept suspended solids and particulate pollutants carried in the runoff generated by the watershed sewage in the early stage of heavy rainfall, and reduce the physical sedimentation pressure in the main degradation zone during the shock load.

[0016] Preferably, the spatial coordinate matrix of the pre-set flow morphology is determined by the hydraulic distribution logic preset based on the biochemical degradation kinetic threshold function, and the spatial coordinate matrix is ​​solidified on the flow interface of the diversion component in the form of physical surface morphology, so that the flow section of the diversion component exhibits a topological change that matches the threshold function with the water level height.

[0017] Preferably, the method is applied to the treatment of distributed non-point source pollution in the hilly areas of southern China. It is used to maintain the biochemical degradation activity and biomass stability of the microbial degradation system in variable working conditions through adaptive diversion regulation of diversion components under seasonal water level fluctuations and instantaneous heavy rainfall runoff impacts.

[0018] The beneficial effects of this invention are:

[0019] 1. In the microbial degradation treatment of organic pollutants in watersheds, a dynamic topological balance between the microbial degradation environment and complex hydraulic conditions is achieved, effectively solving the problem of biochemical system collapse caused by runoff impact in watershed management. This invention utilizes a specific three-dimensional curved surface morphology of the distribution structure to form a nonlinear functional relationship between real-time liquid level changes and the diversion ratio that matches the critical shear force of biofilm peeling. When the instantaneous flow exceeds the system's carrying capacity limit, this morphology guides the fluid to generate specific spatial cutting and diversion, ensuring that the flow field shear stress inside the main degradation zone is always maintained within the adhesion strength threshold of the microbial extracellular polymer. This method of pre-setting control logic through physical morphology enables the biochemical treatment unit to not only cope with drastic fluctuations in external loads, but also to ensure the adhesion stability of the core biological community at the structural level, avoiding the large-area peeling and loss of activity of biofilms that are common in existing technologies.

[0020] 2. Constructing a biochemical remediation mechanism based on automatic hydraulic timing significantly enhances the self-recovery capability of the treatment system after extreme operating conditions. This invention, through the geometric topology design of the distribution interface, utilizes the damping characteristics of the physical structure to naturally extend the hydraulic residence time in the main degradation zone during the low-flow interval after the runoff impact. At this time, a microenvironment with relatively abundant substrate concentration and weak hydraulic scouring is formed inside the system. This environment is highly consistent with the optimal reaction conditions in the microbial degradation rate equation. In this way, the residual nutrients after the impact are converted into the driving force for biomass replenishment, enabling the damaged microbial community to quickly perform metabolic repair and population reconstruction, allowing the system to recover to the rated degradation flux in a short time without human intervention. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a system architecture diagram of the intelligent water quality monitoring and microbial degradation process of the present invention.

[0023] Figure 2 This is a flowchart illustrating the microbial grading and domestication process and adaptive recovery to cope with flow fluctuations in this invention. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] A method for microbial degradation treatment of organic pollutants in a watershed includes the following steps:

[0026] Step S1: Introduce wastewater from the watershed. The wastewater in the watershed exhibits fluctuations in influent flow and organic load due to rainfall and runoff.

[0027] Step S2: The wastewater in the basin is physically divided into two streams by using the pre-set flow morphology of the diversion component: the wastewater in the basin is divided into a degradation flow direction that enters the main degradation zone and an overload flow direction that bypasses the main degradation zone.

[0028] Step S3 guides the degradation flow into the main degradation zone, where it contacts the multi-stage anaerobic biofilm attached to the packing surface and generates a biochemical degradation reaction. The pre-set flow morphology has a geometric interface with a cross-sectional area that adjusts with water level, and this interface possesses flow damping characteristics preset based on microbial metabolic parameters. When the influent flow rate of the wastewater exceeds the preset load limit of the main degradation zone, the pre-set flow morphology, through the physical morphology adjustment of the geometric interface, generates a non-linearly increasing split ratio that rises with water level. This cuts the wastewater exceeding the preset load limit into the overload flow direction, maintaining the flow field shear stress within the main degradation zone within a preset shear stress range lower than the critical adhesion strength of the extracellular polymers of the multi-stage anaerobic biofilm. This stabilizes the attachment structure of the multi-stage anaerobic biofilm and reduces microbial loss.

[0029] Preferably, during the low-flow interval after rainfall, the structural damping characteristics of the pre-set flow morphology are used to reduce the flow velocity in the main degradation zone, thereby extending the hydraulic retention time of the wastewater in the main degradation zone. During the extended hydraulic retention time, the main degradation zone utilizes residual nutrients to induce a population reconstruction response in the damaged microbial community, thereby restoring the main degradation zone to its rated degradation flux.

[0030] Preferably, the multi-stage anaerobic biofilm is constructed through a graded acclimatization process, which includes: in the early stage of biofilm formation, a low shear force flow field of 0.05 m / s to 0.15 m / s is used to induce the initial bacterial community to attach; during the biofilm maturation period, the shear force of the flow field is gradually increased to between 0.5 Pa and 1.2 Pa in order to screen for dominant bacterial communities with extracellular polymer secretion characteristics.

[0031] Preferably, the split ratio defined by the preset flow profile follows the following quantitative constraint rules: ,in, The flow splitting ratio is the overload flow direction, k is the gain coefficient determined by the geometric parameters of the flow splitting component, and h is the real-time water level height within the flow splitting component. The critical water level threshold that triggers the diversion is denoted as m, which is a nonlinear exponent characterizing the flow field cutting characteristics and m>1.

[0032] Preferably, the pre-set flow profile is achieved by setting a cutting edge with a specific geometric curvature at the diversion interface. The radius of curvature of the cutting edge is configured according to the flow cross-sectional area and Reynolds number distribution of the main degradation zone at different water levels, so as to eliminate hydraulic oscillations inside the main degradation zone when the influent flow rate changes abruptly.

[0033] Preferably, the main degradation zone is provided with a honeycomb packing skeleton, and the multi-stage anaerobic biofilm is attached to the inner wall of the honeycomb packing skeleton; the pore size distribution of the honeycomb packing skeleton matches the flow distribution characteristics of the pre-set flow morphology, ensuring that the local shear stress on the inner wall does not exceed 1.5 Pa when the flow distribution ratio is at its maximum.

[0034] Preferably, the biochemical degradation reaction in step S3 is used to synergistically degrade chemical oxygen demand, total nitrogen and total phosphorus in the wastewater of the watershed; the multi-stage anaerobic biofilm forms anaerobic gradient, anoxic gradient and microaerobic gradient distributed along the water flow direction in the main degradation zone, so as to achieve the simultaneous completion of organic matter degradation and nitrogen and phosphorus removal.

[0035] Preferably, the overload flow generated in step S2 is guided into an ecological retention ditch or artificial wetland for end-of-pipe interception, in order to intercept suspended solids and particulate pollutants carried in the runoff generated by the watershed sewage in the early stage of heavy rainfall, and reduce the physical sedimentation pressure in the main degradation zone during the shock load.

[0036] Preferably, the spatial coordinate matrix of the pre-set flow morphology is determined by the hydraulic distribution logic preset based on the biochemical degradation kinetic threshold function, and the spatial coordinate matrix is ​​solidified on the flow interface of the diversion component in the form of physical surface morphology, so that the flow section of the diversion component exhibits a topological change that matches the threshold function with the water level height.

[0037] Preferably, the method is applied to the treatment of distributed non-point source pollution in the hilly areas of southern China. It is used to maintain the biochemical degradation activity and biomass stability of the microbial degradation system in variable working conditions through adaptive diversion regulation of diversion components under seasonal water level fluctuations and instantaneous heavy rainfall runoff impacts.

[0038] Example 1: In the scenario of treating organic pollutants in a watershed in a hilly area of ​​southern China, subject to seasonal water level fluctuations and the impact of instantaneous heavy rainfall runoff, watershed wastewater with fluctuating inflow and organic load is introduced. The diversion function curve of traditional static physical interception facilities and the nonlinear shearing threshold of multi-stage anaerobic biofilms under high shear stress are fundamentally mismatched in their underlying mathematical logic. This leads to the inability of conventional systems to achieve a fully dynamic balance between ensuring total wastewater interception and maintaining biofilm stability. Under the hydraulic impact of heavy rainfall, high flow field shear stress is generated, resulting in large-scale shearing of mature biofilm within the main degradation zone and causing loss of microbial populations. This makes the degradation system physically vulnerable to extreme fluctuations. The pre-designed flow morphology of the diversion component physically diverts the wastewater in the watershed. The spatial coordinate matrix of this pre-designed flow morphology is determined by a hydraulic distribution logic preset based on a biochemical degradation kinetic threshold function and is solidified on the flow interface in the form of a physical surface morphology. When the influent flow rate of the wastewater exceeds the preset load limit of the main degradation zone, the pre-designed flow morphology adjusts the cross-sectional area of ​​the flow through a cutting edge with a specific geometric curvature according to the real-time water level height h. This diverts the wastewater exceeding the carrying capacity limit by bypassing the overload flow direction of the main degradation zone and guiding it into an ecological retention ditch or artificial wetland. This intercepts suspended solids and particulate pollutants carried by the wastewater in the runoff generated at the beginning of heavy rainfall, while simultaneously generating flow according to quantitative constraint rules. The split ratio, where, The flow splitting ratio is the overload flow direction, k is the gain coefficient determined by the geometric parameters of the flow splitting component, and h is the real-time water level height within the flow splitting component. The critical water level threshold for triggering diversion is m, which is a nonlinear exponent characterizing the flow field cutting characteristics and is greater than 1. This nonlinearly increased diversion ratio and the sudden change in influent flow rate form a flow matching, so that the local shear stress generated on the inner wall of the honeycomb packing skeleton by the degradation flow direction guided into the main degradation zone is always no higher than 1.5 Pa. This keeps it within the preset shear stress range below the critical adhesion strength of the extracellular polymer of the multi-stage anaerobic biofilm, suppresses the hydraulic oscillation inside the main degradation zone and stabilizes the attachment structure, so that the system can maintain high biomass while suppressing large-area peeling caused by high-velocity hydraulic scouring.

[0039] During the low-flow interval following the rainfall impact, the structural damping characteristics of the pre-designed flow morphology are used to reduce the flow velocity in the main degradation zone, extending the hydraulic retention time of the wastewater within this zone. This allows the multi-stage anaerobic biofilm, attached to the inner wall of the honeycomb packing skeleton and distributed along the flow direction with anaerobic, anoxic, and microaerobic gradients, to utilize residual nutrients to generate a population rebuilding response. During this extended hydraulic retention time, the system operates according to the model... The degradation rate is adaptively adjusted, where v is the pollutant degradation rate and S is the organic substrate concentration data measured by the system. The pre-configured maximum reaction rate of the microorganisms, The parameter is a semi-saturation constant. Through the adaptive compensation mechanism of hydraulic time series and metabolic intensity, the main degradation zone is restored to the rated degradation flux, and synergistic biochemical degradation reactions are generated for chemical oxygen demand, total nitrogen and total phosphorus in the wastewater of the watershed, so as to maintain the biochemical degradation activity and biomass stability of the microbial degradation system in the variable working environment.

[0040] Example 2: In a hydrodynamic test platform simulating the runoff impact of seasonal rainstorms in the hilly areas of southern China, wastewater with a mean flow rate of 10 m³ / h and a chemical oxygen demand (COD) concentration of 350 mg / L was introduced. Gaussian white noise with a variance of 20% was superimposed on the influent pump control system to simulate the instantaneous flow rate fluctuations and water quality disturbances during rainfall. Hydraulic impact load gradients of 1.5, 3.0, and 5.0 times the baseline flow rate during the dry season were set. A mismatch was found between the diversion function curve of conventional interception technology under extreme variable conditions and the shedding threshold of multi-stage anaerobic biofilms facing high shear forces. This resulted in the flow field shear stress exceeding the biofilm adhesion strength, leading to microbial loss. Nonlinear... The nonlinearity index m is used as the core parameter. The technical consideration for setting this parameter is to balance the instantaneous diversion response rate of the overloaded water flow with the retention of basic nutrient matrix in the main degradation zone. According to the hydrodynamic feedback rule, when the peak flow rate of the watershed sewage approaches the upper limit of the main degradation zone volume, the nonlinearity index m tends to increase in order to improve the discharge ratio. However, under the high-frequency micro-amplitude fluctuation condition, an excessively large nonlinearity index leads to the loss of bottom material and induces microbial dormancy. Therefore, the nonlinearity index m is determined to be greater than 1. The values ​​of 1.5, 2.0 and 2.5 are selected as the gradient verification parameters for the experimental group. A control group 1 using a linear overflow weir is set up, and an out-of-bounds control group 2 with the nonlinearity index m set to 0.8 is set up.

[0041] The hydraulic impact program was initiated, and particle image velocimetry was used to continuously measure the real-time flow field shear stress at the boundary layer of the inner wall of the honeycomb packing skeleton. Under a 5.0 times flow rate impact condition, wastewater containing 20% ​​noise disturbance was introduced. The hydraulic distribution inside control group 1 became unstable, with a local shear stress peak reaching 4.2 Pa. The shear stress peak in control group 2, which exceeded the limit, reached 2.8 Pa. The experimental group utilized a pre-set flow profile, using a cutting edge with specific geometric curvature that nonlinearly amplified the flow cross-sectional area with the real-time water level height h, cutting the water exceeding the bearing capacity into the overload flow direction. The measured nonlinearity index m values ​​of 1.5, 2.0, and 2.5 showed that local fluid kinetic energy was physically dissipated, and the surface shear stress remained at 1.45 Pa, 1.21 Pa, and 1.18 Pa, respectively. The pre-set flow profile was based on the formula... The resulting diversion logic converts hydraulic kinetic energy into diversion potential energy, enabling the core region of the system to maintain a low-shear fluid environment under flow disturbances. Where k is the shunting ratio and k is the gain coefficient. This is the critical water level threshold.

[0042] After 72 hours of continuous shock load testing and low-flow intermittent monitoring, the biomass ratio of attached packing material detachment and the recovery period of chemical oxygen demand removal rate were determined. In control group one, the biofilm detachment rate reached 65%, and the degradation flux did not recover to its initial level within 15 days. In control group two, the detachment rate was 38%, requiring 8 days to recover. The experimental group controlled the detachment rate within the range of 4% to 7%. During the extended hydraulic retention time, the system utilized residual nutrients to generate a population rebuilding response, based on the model. The degradation rate was adjusted to restore 90% of the rated degradation flux within 48 hours after the shock event, where v is the degradation rate. S represents the maximum reaction rate, and S represents the substrate concentration. As a half-saturation constant, gradient data shows that when the nonlinear exponent m increases to the upper limit of 3.0, the shear stress drops to 0.9 Pa. However, the biofilm shedding rate rebounds to 12% due to endogenous respiration aging caused by the lack of nutrient substrate, and the chemical oxygen demand removal rate stabilizes at 75%. This performance inflection point verifies that maintaining the flow field shear stress within the range of no more than 1.5 Pa is the boundary for achieving physical scour resistance and biochemical metabolic balance. The system decouples the technical contradiction between high-velocity hydraulic scour and maintaining high biomass through morphological solidification diversion logic.

[0043] Example 3: In a watershed wastewater treatment scenario where the concentration of organic substrates in natural water bodies exhibits spatiotemporal heterogeneity and the geometric parameters of the diversion components lack a quantitative calibration procedure to match transient impact characteristics, a multi-stage anaerobic biofilm attached to the inner wall of a honeycomb packing skeleton is constructed using a graded acclimation process. The initial operating water temperature of the acclimation reactor is set at 30°C. In the first stage, the dissolved oxygen concentration is controlled to be no higher than 0.1 mg / L by adjusting the closed valve, and a water distribution substrate with a chemical oxygen demand concentration of 800 mg / L is continuously pumped into the acclimation reactor to maintain the dissolved oxygen concentration. In the first stage, anaerobic bacteria are enriched at the bottom layer of the packing material skeleton for 15 days. In the second stage, the aeration rate of the microporous aeration array is adjusted to increase the dissolved oxygen concentration to 0.5 mg / L and the chemical oxygen demand concentration of the water distribution substrate is set at 400 mg / L for 10 days to form anoxic bacteria in the middle layer of the biofilm. In the third stage, the aeration rate of the microporous aeration array is increased to maintain the dissolved oxygen concentration at 1.0 mg / L for 7 days to promote the formation of microaerobic communities on the surface. Thus, anaerobic gradients, anoxic gradients, and microaerobic gradients are generated along the water flow direction on a single packing material cross section.

[0044] A hydrodynamic testing flume was used to simulate the evolution of the influent flow rate of a watershed from its rated baseline value to an impact extreme value of 5.0 times the rated baseline value. Real-time flow field shear stress data at the boundary layer of the inner wall of the packing skeleton was collected using a surface tension sensor matrix. Based on the constraint that the flow field shear stress does not exceed 1.5 Pa, the spatial geometric curvature of the cutting edge of the diversion component was adjusted using CNC equipment. Real-time water level height and the overload flow diversion ratio bypassing the main degradation zone were collected while maintaining this shear stress. The collected water level height and diversion ratio values ​​were then substituted into the constraint rules. Fitting calculation, where, The flow split ratio is a dimensionless parameter for the overload flow direction, k is the gain coefficient, and h is the real-time water level height. The critical water level threshold is determined by the physical volume of the main degradation zone, and m is the nonlinear exponent. From this, the gain coefficient k is calculated to be 0.45 and the nonlinear exponent m is 2.2. Based on the spatial coordinate matrix output by the fitting calculation, the diversion component is processed and integrated with the honeycomb packing material loaded with multi-stage anaerobic biofilm into the main degradation zone. When the degradation system is in response to the impact of sudden heavy rainfall runoff, the spatial geometric curvature solidified at the flow interface divides the overload hydraulic kinetic energy, limits the flow field shear stress within the critical adhesion strength of the multi-stage anaerobic biofilm, inhibits the physical scouring and peeling of the inner layer of fixed anaerobic community, eliminates hydraulic oscillation in the main degradation zone, and stabilizes the biomass and metabolic activity of the microbial degradation system under the condition of sudden change in influent flow.

[0045] Example 4: In the on-site deployment scenario before the commissioning of the watershed degradation system, the organic pollutant components in natural water bodies are specific. The response deviation of the main degradation zone adjustment model is directly generated by applying general benchmark data. The system initiates the in-situ calibration procedure of degradation kinetic indicators. A benchmark water sample from the target watershed is extracted using a sampling device as the test substrate. Mature biofilms from the self-degradation zone are inoculated in a bypass closed isothermal reactor. Test substrates of multiple concentration gradients are sequentially injected into the isothermal reactor using a CNC pump. The amount of substrate consumed per unit mass of biofilm under different initial substrate concentrations within a preset time window is collected simultaneously using an online chemical oxygen demand analyzer. The real-time pollutant degradation rate v corresponding to each substrate concentration gradient S is calculated.

[0046] The acquired multiple sets of substrate concentration gradients S and corresponding real-time pollutant degradation rate v data sequences are imported into the calculation module, and the kinetic model is analyzed based on the nonlinear least squares method. Fitting and extracting the extreme values ​​of the asymptotes after fitting convergence as the maximum microbial reaction rate under specific water quality conditions in a specific watershed. The x-axis value corresponding to 0.5 times the maximum microbial reaction rate was extracted as the half-saturation constant. The maximum reaction rate of the calibrated microorganisms With half-saturation constant The compensation controller for the main degradation zone is powered by a 12V solar battery. Its main control chip monitors the real-time organic substrate concentration at a sampling frequency of 1Hz when the real-time water level is below the critical water level threshold. When the real-time water level exceeds the critical water level threshold, the controller enters a sleep mode and passively diverts the flow entirely through the physical morphology of the diversion components. This ensures that during heavy rainfall, no electric drive is required to offset the high shear force through physical cutting. The system updates the calculation benchmark for adjusting the degradation rate based on real-time organic substrate concentration data during low-flow intervals, enabling the main degradation zone to generate biochemical degradation reactions for specific watershed wastewater based on quantitative parameters of local water quality characteristics.

[0047] Example 5: In the pre-deployment preparation scenario of a degradation system in a specific hilly area in southern China, the impact intensity of rainfall-runoff caused by local topography leads to excessive shear stress in the local flow field within the main degradation zone due to the application of general geometric parameters to the diversion component. The system lacks a physical morphology quantitative calibration procedure that matches the hydraulic characteristics of this specific watershed. Therefore, an offline optimization calibration process for the geometric interface of the diversion component is initiated. Historical high-water season extreme flow data of the target watershed are selected as the test input benchmark. A computational fluid dynamics model mapping the physical boundary of the main degradation zone and the resistance characteristics of the honeycomb packing skeleton is constructed. In constructing this computational fluid dynamics model, the main degradation zone is defined as a regular geometric cavity with a fixed hydraulic gradient, and a porous media model is used to equivalently simulate the damping effect of the honeycomb packing skeleton on the fluid. The fluid motion in this model follows the following Navier-Stokes governing equations: ,in, The fluid velocity vector within the main degradation zone; For fluid pressure; To calculate the real-time time step in the computational fluid dynamics simulation process; The density of the wastewater in the watershed is taken as a constant in this embodiment. ; The dynamic viscosity of the wastewater is used as the inlet velocity boundary condition in the equations, based on the measured extreme flow rate during the high-water season of the specific watershed. The dynamic viscosity is then dynamically corrected according to the real-time water temperature to anchor the transient response of the flow field under specific hydraulic impact characteristics. The volumetric force term includes the packing resistance; the critical adhesion strength of the multi-stage anaerobic biofilm is transformed into a wall shear stress threshold not exceeding 1.5 Pa and set as the hard constraint boundary of this computational fluid dynamics model, with the wall shear stress... The calculation logic conforms to the following formula definition: ,in, This represents the velocity gradient at the inner wall surface of the honeycomb packing. The formula, representing the normal distance perpendicular to the wall, quantifies the relationship between the microscopic biofilm adhesion strength and macroscopic hydraulic parameters. Extreme flow rate data is injected into the computational fluid dynamics model, and the dynamic rise of the water level h is calculated. A numerical solver iteratively adjusts the spatial three-dimensional coordinate matrix of the pre-set flow topography cutting edge. During the iteration process, the spatial three-dimensional coordinate matrix... The generation logic is limited by the vertical height of the diversion component (the z-axis with the bottom of the diversion component's flow interface as the zero point, corresponding to the real-time water level). The opening width function on ) By changing The geometric curvature is adjusted to change the effective cross-sectional area of ​​the diversion interface, aiming to artificially induce a local reverse pressure gradient field below the overflow outlet, so that the high-speed flow jet generates controlled boundary layer stripping and steady-state micro vortices. The transient hydraulic kinetic energy carried by the runoff is substantially dissipated through the friction between the vortices, thereby nonlinearly suppressing the fluid velocity vector inside the main degradation zone.

[0048] In each grid iteration, the flow field distribution and wall shear stress under the corresponding geometric curvature are calculated. Coordinate combinations that cause the shear stress to exceed the 1.5 Pa threshold are filtered out. The optimal spatial coordinate matrix that maximizes the overload flow splitting ratio that makes the shear stress in the main degradation zone close to the threshold and bypasses the main degradation zone under full load conditions is extracted. The splitting ratio data sequence output by the optimal spatial coordinate matrix at different simulated water level heights h is recorded. This data sequence is then substituted into the constraint rules. The Levenberg-Marquardt nonlinear least squares method is used for fitting calculations, where... The flow split ratio is a dimensionless parameter for the overload flow direction, k is the gain coefficient, and h is the real-time water level height. Based on the critical water level threshold determined by the volume of the main degradation zone, m is a nonlinear exponent. Thus, the gain coefficient k adapted to this specific watershed is calculated to be 0.38 and the nonlinear exponent m is 2.1. Based on this optimal spatial coordinate matrix, physical diversion components are manufactured and assembled into the front end of the main degradation zone. This makes the flow morphology of the customized physical diversion components match the transient impact characteristics of the target watershed. The overload hydraulic kinetic energy is divided by the determined geometric curvature to control the fluid shear stress on the surface of the biofilm.

[0049] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for the microbial degradation treatment of organic pollutants in a watershed, characterized in that, Includes the following steps: Step S1: Introduce wastewater from the watershed. The wastewater in the watershed exhibits fluctuations in influent flow and organic load due to rainfall and runoff. Step S2: The wastewater in the basin is physically divided by the pre-set flow morphology of the diversion component, and the wastewater in the basin is divided into the degradation flow direction that enters the main degradation zone and the overload flow direction that bypasses the main degradation zone. Step S3 guides the degradation flow into the main degradation zone, where it contacts the multi-stage anaerobic biofilm attached to the packing surface and generates a biochemical degradation reaction. The pre-set flow morphology has a geometric interface with a cross-sectional area that adjusts with water level, and this interface possesses flow damping characteristics preset based on microbial metabolic parameters. When the influent flow rate of the wastewater exceeds the preset load limit of the main degradation zone, the pre-set flow morphology, through the physical morphology adjustment of the geometric interface, generates a non-linearly increasing split ratio that rises with water level. This cuts the wastewater exceeding the preset load limit into the overload flow direction, maintaining the flow field shear stress within the main degradation zone within a preset shear stress range lower than the critical adhesion strength of the extracellular polymers of the multi-stage anaerobic biofilm. This stabilizes the attachment structure of the multi-stage anaerobic biofilm and reduces microbial loss.

2. The method for microbial degradation treatment of organic pollutants in a watershed according to claim 1, characterized in that, During the low-flow intervals following rainfall, the structural damping characteristics of the pre-set flow morphology are used to reduce the flow velocity in the main degradation zone, thereby extending the hydraulic retention time of wastewater in the main degradation zone. During the extended hydraulic retention time, the main degradation zone utilizes residual nutrients to induce a population reconstruction response in the damaged microbial community, restoring the main degradation zone to its rated degradation flux.

3. The method for microbial degradation treatment of organic pollutants in a watershed according to claim 1, characterized in that, Multi-stage anaerobic biofilms are constructed through a graded acclimatization process, which includes: in the early stage of biofilm formation, a low shear force flow field of 0.05 m / s to 0.15 m / s is used to induce the initial bacterial community to attach; during the biofilm maturation period, the shear force of the flow field is gradually increased to between 0.5 Pa and 1.2 Pa in order to screen for dominant bacterial communities with extracellular polymer secretion characteristics.

4. The method for microbial degradation treatment of organic pollutants in a watershed according to claim 1, characterized in that, The split ratio defined by the preset flow topography follows the following quantization constraint rules: ,in, The flow splitting ratio is the overload flow direction, k is the gain coefficient determined by the geometric parameters of the flow splitting component, and h is the real-time water level height within the flow splitting component. The critical water level threshold that triggers the diversion is denoted as m, which is a nonlinear exponent characterizing the flow field cutting characteristics and m>

1.

5. The method for microbial degradation treatment of organic pollutants in a watershed according to claim 1, characterized in that, The pre-set flow profile is achieved by setting a cutting edge with a specific geometric curvature at the diversion interface. The radius of curvature of the cutting edge is configured according to the cross-sectional area and Reynolds number distribution of the main degradation zone at different water levels, so as to eliminate hydraulic oscillations inside the main degradation zone when the influent flow rate changes abruptly.

6. The method for microbial degradation treatment of organic pollutants in a watershed according to claim 1, characterized in that, The main degradation zone is equipped with a honeycomb packing skeleton, and a multi-stage anaerobic biofilm is attached to the inner wall of the honeycomb packing skeleton. The pore size distribution of the honeycomb packing skeleton matches the flow distribution characteristics of the pre-set flow morphology, ensuring that the local shear stress on the inner wall does not exceed 1.5 Pa when the flow distribution ratio is at its maximum.

7. The method for microbial degradation treatment of organic pollutants in a watershed according to claim 1, characterized in that, The biochemical degradation reaction in step S3 is used to synergistically degrade chemical oxygen demand, total nitrogen and total phosphorus in the wastewater of the watershed; the multi-stage anaerobic biofilm forms anaerobic gradient, anoxic gradient and microaerobic gradient distributed along the water flow direction in the main degradation zone, so as to achieve the simultaneous completion of organic matter degradation and nitrogen and phosphorus removal.

8. The method for microbial degradation treatment of organic pollutants in a watershed according to claim 1, characterized in that, The overload flow generated in step S2 is guided into ecological retention ditches or artificial wetlands for end-of-pipe interception, in order to intercept suspended solids and particulate pollutants carried in the runoff generated by the watershed sewage in the early stage of heavy rainfall, and reduce the physical sedimentation pressure in the main degradation zone during the shock load period.

9. The method for microbial degradation treatment of organic pollutants in a watershed according to claim 1, characterized in that, The spatial coordinate matrix of the pre-set flow morphology is determined by the hydraulic distribution logic based on the threshold function of biochemical degradation kinetics. The spatial coordinate matrix is ​​then solidified on the flow interface of the diversion component in the form of a physical surface morphology, so that the flow section of the diversion component exhibits a topological change that matches the threshold function as the water level rises.

10. The method for microbial degradation treatment of organic pollutants in a watershed according to claim 1, characterized in that, The method is applied to the treatment of distributed non-point source pollution in the hilly areas of southern China. It is used to maintain the biochemical degradation activity and biomass stability of the microbial degradation system in variable working conditions by adaptive diversion control of diversion components under seasonal water level fluctuations and instantaneous heavy rainfall runoff impacts.

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