A watershed non-point source pollution gradient interception and ecological purification system

Abstract

The application discloses a kind of basin non-point source pollution cascade interception and ecological purification system, it is related to basin water environment management and non-point source pollution control technical field, the system includes following component parts: coupling monitoring module, hydraulic control module, water purification module, purification efficiency evaluation module, parameter optimization module;The application realizes hydrology and water quality synchronous acquisition, bidirectional correlation modeling by coupling monitoring module, accurately deduces water quality change, optimizes hydraulic control and purification process, breaks traditional limitation, considers flood safety and pollution purification, adapts complex working condition;Through purification efficiency evaluation and parameter optimization module, form full-process closed-loop iterative optimization mechanism, dynamically adjust purification strategy, without frequent human intervention, solve the problem such as traditional technology parameter fixed, enhance adaptive capacity, provide stable technical support.

Description

Technical Field

[0001] This invention relates to the field of watershed water environment management and non-point source pollution control technology, specifically a watershed non-point source pollution cascade interception and ecological purification system. Background Technology

[0002] Non-point source pollution in my country's river basins has become a major cause of eutrophication and water quality deterioration. Agricultural planting and urban surface runoff carry large amounts of pollutants such as COD, ammonia nitrogen, and total phosphorus into rivers, characterized by dispersion, randomness, and large load fluctuations. Traditional river basin pollution control often employs decentralized purification facilities, with hydrological and water quality monitoring operating independently and lacking a two-way correlation mechanism, making it difficult to accurately predict changes in pollution loads. Furthermore, purification facilities are disconnected from hydraulic regulation, hindering the coordination of flood control safety and pollution purification. The integration and intelligence of cascade interception and ecological purification are insufficient, failing to meet the high-efficiency purification needs under the variable hydrological conditions of river basins.

[0003] Existing watershed non-point source pollution remediation technologies have many shortcomings: First, most remediation units are single-stage deployments, lacking a tiered, progressive interception, adsorption, and degradation structure, resulting in a single pollutant removal path and poor graded remediation effects for COD, ammonia nitrogen, and total phosphorus. Second, hydrological and water quality monitoring are separated, and a two-way coupled model has not been constructed, leading to low accuracy in pollution load prediction and an inability to provide precise data support for regulation. Third, hydraulic regulation methods are crude, failing to take flood control safety as a rigid constraint and maximizing hydraulic retention time as the goal; flow allocation and weir regulation lack quantitative algorithms, making it difficult to improve remediation efficiency. Fourth, there is no real-time remediation efficiency assessment and closed-loop parameter optimization mechanism; media ratios and plant configurations are fixed, making it impossible to correct remediation shortcomings in a timely manner, resulting in severe deficiencies in system adaptability and long-term effectiveness.

[0004] In summary, existing technologies, due to insufficient monitoring coupling, crude control modes, single purification levels, and lack of closed-loop optimization, cannot achieve precise interception and efficient ecological purification of watershed non-point source pollution, and struggle to balance flood control safety and purification efficiency. This invention addresses these shortcomings by integrating five modules: coupled monitoring, intelligent hydraulic control, cascade ecological purification, efficiency assessment, and parameter optimization. This constructs a closed-loop operating system that can accurately adapt to hydrological fluctuations, maximize purification efficiency, and ensure flood control safety, providing an efficient and feasible technical solution for the comprehensive management of watershed non-point source pollution. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a watershed non-point source pollution cascade interception and ecological purification system. It can simultaneously collect hydrological and water quality data, establish a two-way coupling model, optimize hydraulic regulation, extend the residence time of pollutants, and use cascade purification structures, media, and plants to treat pollutants step by step. At the same time, it can evaluate purification efficiency in real time, dynamically adjust parameters, form a closed-loop optimization mechanism, and improve its self-adaptive and long-term operation capabilities.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a watershed non-point source pollution cascade interception and ecological purification system, the system comprising the following components: a coupled monitoring module, a hydraulic control module, a water quality purification module, a purification efficiency evaluation module, and a parameter optimization module;

[0007] The coupled monitoring module synchronously collects rainfall, runoff, and water level hydrological data across the entire watershed section, as well as COD, ammonia nitrogen, and total phosphorus water quality data. After performing time-series alignment and standardization preprocessing on the collected data, it establishes a hydrological-water quality bidirectional coupled correlation model and outputs water quality change trends and pollution load prediction results under different hydrological scenarios.

[0008] The hydraulic control module receives water quality change trends and pollution load prediction results. Taking the safety of flood control in the basin as a rigid constraint and maximizing the hydraulic residence time of pollutants as the optimization goal, it adjusts the opening degree of the cascade weirs and the proportion of inflow distribution, and distributes the water to be purified to the water purification module according to the optimized proportion.

[0009] The water purification module receives the water to be purified from the hydraulic control module, and through a tiered purification structure, differentiated purification media and functional plants, it intercepts, adsorbs, degrades and removes COD, ammonia nitrogen and total phosphorus pollutants in the water step by step, and outputs purified water.

[0010] The purification efficiency evaluation module is connected to the inlet and outlet of the water purification module at each stage, collects water quality data from each stage in real time, calculates the purification efficiency of a single indicator and the overall purification efficiency of the system, identifies shortcomings in purification efficiency, and generates a complete purification efficiency evaluation report and suggestions for optimization.

[0011] The parameter optimization module receives the purification efficiency assessment report and optimization direction suggestions, combines them with the real-time prediction data from the coupled monitoring module, generates optimized operating parameters, and reversely adjusts the weir opening degree and influent flow distribution ratio of the hydraulic control module, as well as the purification medium ratio of the water purification module, to complete the iterative optimization of the system operating parameters.

[0012] Furthermore, the coupled monitoring module acquires hydrological data such as rainfall, runoff, and water level, as well as water quality data such as COD, ammonia nitrogen, and total phosphorus across the entire watershed during a unified collection period. It performs outlier removal, time-series alignment, and dimensional standardization preprocessing on the collected multi-source data. A hydrological-water quality bidirectional coupled correlation model is constructed, employing a four-layer structure: input layer, coupling correlation layer, deduction layer, and output layer. The input layer loads standardized time-series hydrological and water quality data; the coupling correlation layer establishes a bidirectional transmission correspondence between hydrological elements and water quality indicators; the deduction layer performs time-series deduction of water quality changes based on different hydrological scenarios; and the output layer outputs the corresponding water quality change trends and pollution load prediction results.

[0013] Furthermore, the working process of the hydraulic control module is as follows: receiving the water quality change trend and pollution load spatial distribution results, extracting the runoff change range, the highest predicted water level, and pollution load characteristic data within the prediction period; combining the flood control safety control water level, defining the adjustable range of the opening degree of the cascade weirs, and constraining the influent flow distribution ratio of each purification unit of the water quality purification module within the range of 0% to 35% for a single stage, and the sum of the influent flow distribution ratios of each purification unit is 100%; within the defined adjustable range and constraint range, solving for the opening degree of the cascade weirs and the influent flow distribution ratio of each purification unit; generating control commands based on the solution results, driving the cascade weirs to adjust their opening degree, and simultaneously driving the water flow distribution valve group to adjust the influent flow of each purification unit.

[0014] Furthermore, the calculation formulas for the ratio of the opening degree of the cascade weirs and the influent flow distribution ratio of each purification unit in the hydraulic control module are as follows:

[0015]

[0016]

[0017] in, The opening degree of the cascade weir, in meters; The water level is for flood control safety, and the unit is meters (m). The real-time monitoring water level upstream of the cascade weir is shown in meters (m). The total flow rate entering the water purification module is expressed in m³ / s and is equal to the sum of the inflow rates of each purification unit. The flow coefficient of the cascade weir is determined by the structural form and weir surface material of the weir through hydraulic engineering tests. The overflow net width of the cascade weir dam is expressed in meters (m). The acceleration due to gravity is fixed at 9.81 m / s². The head of water approaching the weir is measured in meters. The influent flow rate allocation ratio for the i-th stage purification unit satisfies... ; This is the sequence number of the tiered purification unit within the water purification module, ranging from 1 to n, where n is the total number of purification stages. The effective design volume of the i-th stage purification unit is expressed in m³. The pollutant degradation characteristic coefficient of the i-th stage purification unit is determined by field tests based on the media type, filling rate, and plant configuration of this stage purification unit.

[0018] Furthermore, the water purification module is arranged sequentially along the water flow direction, consisting of a primary interception purification unit, a secondary adsorption purification unit, a tertiary biodegradation purification unit, and a quaternary ecological stabilization purification unit. Each purification unit is equipped with an independent controllable inlet and outlet. The inlet is connected to the water flow distribution valve group of the hydraulic control module, and the outlet is connected in series to the inlet of the next purification unit, forming a stepped, closed water flow path. The primary interception purification unit is filled with coarse filter media such as pebbles and quartz sand, the secondary adsorption purification unit is filled with modified zeolite and granular activated carbon media, the tertiary biodegradation purification unit is filled with biochar and porous microbial carriers, and the quaternary ecological stabilization purification unit is planted with aquatic functional plants.

[0019] Furthermore, the influent flow rate of each purification unit in the water purification module is controlled by the hydraulic control module according to the influent flow rate allocation ratio. The sum of the influent flow rates of each purification unit is equal to the total outflow into the water purification module. When the highest predicted water level in the prediction results output by the coupled monitoring module exceeds the flood control safety level, the hydraulic control module synchronously adjusts the opening degree of the cascade weir and the influent flow rate of each purification unit. While meeting the flood control safety level requirements, it allocates water from the total inflow of the river to the water purification module at a rate not lower than the preset minimum treatment flow rate. The preset minimum treatment flow rate is 15% to 20% of the total designed rated influent flow rate of the water purification module, and the influent flow rate allocation ratio of each purification unit does not exceed the constraint range of 0% to 35% for each stage defined by the water purification module.

[0020] Furthermore, the specific working process of the purification efficiency assessment module is as follows: water quality monitoring points are set up at the inlet and outlet of each purification unit of the water purification module, and the COD, ammonia nitrogen, and total phosphorus concentration data of the influent and effluent of each purification unit are collected synchronously with the time step of the coupled monitoring module; based on the collected influent and effluent water quality data, the single-index purification efficiency of each purification unit and the overall purification efficiency of the system are calculated; the design purification efficiency threshold of each purification unit is compared with the actual calculated purification efficiency to identify purification units with substandard efficiency and weak pollutant indicators; the real-time monitoring data, efficiency calculation results, and weak point identification conclusions are integrated to generate a purification efficiency assessment report and optimization direction suggestions.

[0021] Furthermore, the purification efficiency evaluation module calculates the single-index purification efficiency of each purification unit and the overall system purification efficiency using the following formulas:

[0022]

[0023]

[0024] in, The purification efficiency of the j-th pollutant in the i-th purification unit is expressed as a single indicator (%). This is the sequence number of the tiered purification unit within the water purification module, ranging from 1 to n, where n is the total number of purification stages. The index is the serial number of the pollutant indicator, ranging from 1 to m, where m is the total number of pollutant indicators, corresponding to the three indicators: COD, ammonia nitrogen, and total phosphorus. The real-time monitoring concentration of the j-th pollutant indicator at the inlet of the i-th purification unit is given in mg / L. The real-time monitoring concentration of the j-th pollutant indicator at the outlet of the i-th purification unit is given in mg / L. The overall purification efficiency of the system is expressed in % (%). Let be the weight coefficient of the j-th pollutant indicator, and the sum of all weight coefficients is 1; The real-time monitoring concentration of the jth pollutant at the main inlet of the purification system is given in mg / L. The real-time monitoring concentration of the jth pollutant at the main outlet of the purification system is given in mg / L.

[0025] Furthermore, the specific working process of the parameter optimization module is as follows: It receives the purification efficiency assessment report and optimization direction suggestions output by the purification efficiency assessment module, and simultaneously retrieves real-time hydrological and water quality data and preset time period prediction results from the coupled monitoring module; it analyzes the received full data to pinpoint the specific location and causes of hydrological prediction deviations, hydraulic control parameter deviations, and purification efficiency shortcomings during system operation; based on the analysis results and combined with future hydrological and water quality changes, it generates optimized hydraulic control parameters and purification module operating parameters. The hydraulic control parameters include the opening degree of the cascade weirs and the water flow distribution ratio of each purification unit, while the purification module operating parameters include the purification medium replenishment ratio and functional plant maintenance strategies; the optimized parameters are converted into standard execution instructions and synchronously sent to the hydraulic control module and water quality purification module to complete the reverse adjustment and closed-loop iteration of the system operating parameters.

[0026] Compared with existing technologies, this watershed non-point source pollution cascade interception and ecological purification system has the following beneficial effects:

[0027] I. This invention achieves synchronous acquisition, time-series alignment, and bidirectional correlation modeling of watershed hydrological and water quality data through a coupled monitoring module. It accurately predicts water quality changes and pollution load distribution under different hydrological scenarios. Relying on the hydraulic control module with flood control safety as a rigid constraint, it optimizes the operation status of cascade weirs and dams and the water flow distribution scheme, extends the hydraulic residence time of pollutants, and combines the purification structure deployed in cascades with differentiated purification media and functional plants to carry out step-by-step interception, adsorption, and degradation treatment of water pollutants. It constructs a progressive purification process, breaking the limitations of the separation of hydrological and water quality monitoring and the disconnect between hydraulic control and purification links in traditional technologies. It simultaneously takes into account the needs of watershed flood control safety and pollution purification, significantly improves the pollutant removal effect, and enables the system to adapt to the complex and ever-changing hydrological conditions of the watershed, ensuring the stability and adaptability of the water purification process.

[0028] Second, this invention collects real-time water quality data of influent and effluent from each level of purification unit through a purification efficiency assessment module, accurately calculates individual indicators and overall purification efficiency, quickly identifies shortcomings in the purification process and identifies optimization directions, and generates suitable operating parameters based on a parameter optimization module combined with real-time monitoring and prediction data. This generates parameters that are then used to adjust hydraulic control and water purification processes, forming a closed-loop iterative optimization mechanism that dynamically adjusts the purification medium ratio and functional plant maintenance strategies. This allows for continuous optimization of the system's operating status without frequent manual intervention, solving the problems of fixed parameters, inability to improve efficiency in real time, and high operation and maintenance costs associated with traditional purification technologies. It significantly enhances the system's adaptability and long-term operational level, maintaining a consistently high-efficiency purification state and providing stable and sustainable technical support for the treatment of non-point source pollution in watersheds.

[0029] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0031] Figure 1 A block diagram showing the modular components of a watershed non-point source pollution cascade interception and ecological purification system;

[0032] Figure 2 This is a flowchart illustrating the overall operation of a watershed non-point source pollution cascade interception and ecological purification system.

[0033] Figure 3 This is a flowchart illustrating the calculation and execution process of a hydraulic control module for a watershed non-point source pollution cascade interception and ecological purification system. Detailed Implementation

[0034] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0035] Example 1

[0036] The coupled monitoring module synchronously collects rainfall, runoff, and water level hydrological data, as well as COD, ammonia nitrogen, and total phosphorus water quality data for the entire cross-section of the plain agricultural watershed, according to a unified collection period. The collected multi-source heterogeneous data undergoes outlier removal, time-series alignment, and dimensional standardization preprocessing in sequence. This process removes abnormal values ​​caused by equipment failure or environmental interference during data collection, unifies the data collection time nodes of different monitoring points, and eliminates analytical biases caused by different dimensions of various data. This allows hydrological and water quality data to form a unified and accurate analytical benchmark, laying a solid data foundation for subsequent model construction and data extrapolation. The module constructs a four-layer hydrological-water quality bidirectional coupling and correlation model, consisting of an input layer, a coupling and correlation layer, a deduction layer, and an output layer. The input layer fully loads standardized time-series hydrological and water quality data, ensuring the integrity and standardization of the data input. The coupling and correlation layer establishes a bidirectional transmission correspondence between hydrological elements and water quality indicators, allowing dynamic changes in rainfall, runoff, and water level to accurately map with fluctuations in COD, ammonia nitrogen, and total phosphorus concentrations, clearly showing the direct impact of changes in hydrological conditions on pollution indicators. The deduction layer completes time-series deduction of water quality changes based on different hydrological scenarios, fully reconstructing rainfall and irrigation periods. The system tracks the complete patterns of pollution migration, transformation, and diffusion within the basin under various hydrological conditions, including dry seasons. The output layer stably outputs water quality change trends and pollution load predictions under different hydrological scenarios, allowing for advance prediction of peak pollution load times, key water quality deterioration points, and spatial distribution of pollution within the basin. This provides real, effective, and forward-looking data support for subsequent hydraulic regulation and water purification, ensuring that all system operations are based on the real-time hydrological and water quality status of the basin. It comprehensively covers the monitoring needs of the entire basin section, leaving no blind spots in pollution monitoring, and ensuring that the entire governance system always operates in accordance with the actual state of the basin.

[0037] The hydraulic control module receives the water quality change trend and pollution load prediction results output by the coupled monitoring module, extracts the runoff variation range, highest predicted water level, and pollution load characteristic data within the prediction period, and delineates the adjustable range of the opening degree of the cascade weirs and dams based on the core rigid constraint of watershed flood control safety and the flood control safety control water level. Simultaneously, it clarifies the constraint range of the influent flow distribution ratio of each purification unit in the water quality purification module. Within the compliant control range, the optimal operating parameters are solved using the cascade weir and dam opening degree calculation formula and the influent flow distribution ratio calculation formula. The calculation formulas are as follows: , ,in, The opening degree of the cascade weir dam; To ensure safe flood control, water levels must be controlled. Real-time monitoring of water levels upstream of the cascade weir dam; This refers to the total flow rate entering the water purification module; The flow coefficient of the cascade weir dam; The overflow net width of the cascade weir dam; It is the acceleration due to gravity; To advance towards the water head of the weir; The proportion of inlet water flow allocated to the i-th stage purification unit; This refers to the serial number of the cascade purification unit within the water purification module; This represents the effective design volume of the i-th stage purification unit; This represents the pollutant degradation characteristic coefficient of the i-th level purification unit. The solution ensures that the results simultaneously meet the flood control safety baseline requirements and the optimization objective of maximizing the hydraulic residence time of pollutants, allowing sufficient treatment time for the water body within the purification unit and fully releasing the pollution removal potential of each level of purification unit. The module generates standardized control commands based on the solution results, driving precise adjustment of the opening degree of the cascade weirs and dams, and simultaneously driving the water flow distribution valve group to adjust the influent flow rate of each level of purification unit. This stably distributes the water to be purified to the water quality purification module according to the optimized ratio, strictly controlling the real-time water level of the basin to always be below the flood control safety level, eliminating the risk of flooding in the basin, ensuring the safe operation of agricultural production facilities and village infrastructure around the basin, achieving a balance between precise hydraulic control and efficient pollution purification. This ensures that the water allocation ratio is highly adapted to the real-time hydrological status and pollution load of the basin, improving the rationality and effectiveness of non-point source pollution control from the source, and ensuring that the water quality purification module always operates under optimal influent conditions, avoiding a decrease in purification effect due to influent flow imbalance.

[0038] The water purification module receives the water to be purified, which is allocated by the hydraulic control module according to an optimized ratio. The water flows sequentially through a primary interception purification unit, a secondary adsorption purification unit, a tertiary biodegradation purification unit, and a quaternary ecological stabilization purification unit. Each purification unit is equipped with an independent and controllable inlet and outlet. The inlets are connected to the water flow distribution valve group of the hydraulic control module, and the outlets are connected in series to form a stepped, closed water flow path. This ensures that the water is purified step by step according to the predetermined process, without short circuits, leaks, or short flows, thus guaranteeing the integrity and stability of the purification process. The primary interception and purification unit is filled with coarse filter media of pebbles and quartz sand, which physically intercepts large particulate suspended pollutants and silt impurities in the water, significantly reducing the treatment load of subsequent purification units, extending the service life of the purification media, and ensuring the smooth operation of subsequent purification stages. The secondary adsorption purification unit is filled with modified zeolite and granular activated carbon media, which efficiently adsorb dissolved pollutants such as ammonia nitrogen and total phosphorus in the water, rapidly reducing the basic concentration of pollutants in the water and laying the foundation for deep purification. The tertiary biodegradation purification unit is filled with biochar and porous microbial carriers, providing a stable attachment and growth environment for functional microorganisms. Through the metabolic action of microorganisms, organic pollutants such as COD in the water are deeply degraded, decomposing organic pollutants at their source and achieving the harmless transformation of pollutants. The quaternary ecological stabilization purification unit is planted with aquatic functional plants. Through the absorption, adsorption, and rhizosphere microecological regulation of the plants, the remaining pollutants in the water are finally removed. At the same time, the ecological structure of the water body is stabilized, and the ecological stability of the purified water is improved, so that the effluent not only meets the standards but also adapts to the ecological needs of the watershed. The system works collaboratively at all levels to intercept, adsorb, degrade, and remove COD, ammonia nitrogen, and total phosphorus pollutants in water bodies step by step, continuously reducing the concentration of pollutants in the water and ultimately outputting purified water that meets treatment standards. It is perfectly adapted to the composition characteristics of non-point source pollution in plain agricultural watersheds, maximizes the treatment efficiency of various purification media and functional plants, forms a complete ecological purification chain, avoids the shortcomings of single purification methods, and achieves full-process and all-round purification of non-point source pollution.

[0039] The purification efficiency assessment module is stably connected to the inlet and outlet of each stage of the water purification module. Dedicated water quality monitoring points are deployed at the inlet and outlet of each purification unit, maintaining a unified time step with the coupled monitoring module. This synchronously collects COD, ammonia nitrogen, and total phosphorus concentration data from the inlet and outlet of each purification unit, ensuring the timeliness, consistency, and completeness of the monitoring data and accurately reflecting the real-time operating status of each purification unit. Based on the collected complete inlet and outlet water quality data, the module accurately calculates the single-index purification efficiency of each purification unit and the overall system purification efficiency using both single-index purification efficiency calculation formulas and system-wide comprehensive purification efficiency calculation formulas. The calculation formulas are as follows: , ,in, Let J be the single-index purification efficiency of the j-th pollutant index in the i-th purification unit. This refers to the serial number of the cascade purification unit within the water purification module; This refers to the serial number of the pollutant indicator; The real-time monitoring concentration of the j-th pollutant indicator at the inlet of the i-th purification unit; The real-time monitoring concentration of the j-th pollutant indicator at the outlet of the i-th purification unit; For the overall purification efficiency of the system; is the weighting coefficient for the j-th pollutant indicator; The real-time monitoring concentration of the j-th pollutant indicator at the main inlet of the purification system; This module provides real-time monitoring of the concentration of pollutant j at the main outlet of the purification system; it quantifies the removal efficiency of different pollutants by each unit, clearly presenting the operational efficiency and contribution of each purification unit. The module compares the designed purification efficiency thresholds of each purification unit with the actual calculated purification efficiency, quickly identifying purification units that fail to meet efficiency standards and the weakest pollutant indicators, accurately pinpointing the weak links in the purification process, and providing specific directions for system optimization. The module integrates real-time monitoring data, efficiency calculation results, and weakness identification conclusions to generate a complete purification efficiency assessment report and optimization direction suggestions, providing clear and concrete adjustment basis for system parameter optimization. This makes the effectiveness of watershed non-point source pollution control quantifiable and traceable, avoiding the continuous operation of ineffective treatment links, significantly improving the targeting and accuracy of system governance, and ensuring that the entire purification system maintains a consistently high-efficiency operating state.

[0040] The parameter optimization module receives the purification efficiency assessment report and optimization direction suggestions output by the purification efficiency assessment module. Simultaneously, it retrieves real-time hydrological and water quality data and preset time-period prediction results from the coupled monitoring module. It performs comprehensive and in-depth analysis of all received data to accurately pinpoint the specific location and causes of hydrological prediction deviations, hydraulic control parameter deviations, and purification efficiency shortcomings during system operation. This clearly identifies the root causes of problems in system operation, avoiding operational risks from blind adjustments. Based on the analysis results and considering the dynamic changes in future hydrological and water quality, the module generates optimized hydraulic control parameters and purification module operating parameters. These optimized parameters are converted into standard execution commands and simultaneously sent to the hydraulic control module and water purification module. This reverse adjustment controls the weir opening degree and influent flow distribution ratio of the hydraulic control module, as well as the purification medium ratio of the water purification module, ensuring that the system operating parameters are always highly matched with the real-time hydrological and water quality status of the basin and the actual operating effect of the purification units. The module completes iterative optimization of system operating parameters, realizes closed-loop autonomous control of the system, continuously improves the system's purification efficiency and operational stability, enables the system to adapt to the periodic fluctuations of hydrology and water quality in plain agricultural watersheds, maintains a high efficiency in non-point source pollution control in the long term, and can always maintain the optimal operating state without frequent human intervention, ensuring the long-term effectiveness and stability of watershed non-point source pollution control, continuously improving the water environment quality of plain agricultural watersheds, and building a healthy and stable watershed aquatic ecosystem.

[0041] This invention relates to a system for controlling non-point source pollution in plain agricultural watersheds. With watershed flood control safety as a rigid constraint, it achieves efficient interception and ecological purification of non-point source pollution through the closed-loop coordinated operation of five modules: coupled monitoring, hydraulic regulation, water purification, purification efficiency assessment, and parameter optimization. The coupled monitoring module enables synchronous acquisition, standardized processing, and two-way coupled prediction of hydrological and water quality data across the entire cross-section, providing accurate data support for system operation. The hydraulic regulation module optimizes weir opening and flow distribution based on core calculation formulas, maximizing the hydraulic residence time of pollutants. The water purification module removes COD, ammonia nitrogen, and total phosphorus in a four-stage cascade, forming a complete ecological purification chain. The purification efficiency assessment module quantifies the treatment effect and identifies bottlenecks. The parameter optimization module enables autonomous iteration of operating parameters, such as… Figure 1 As shown, the system is perfectly adapted to the periodic fluctuations in hydrology and water quality in plain agricultural watersheds, taking into account both flood control safety and pollution control. It can operate stably and efficiently for a long time, effectively solving the problems of dispersed and difficult-to-treat agricultural non-point source pollution, continuously improving the water environment quality of the watershed, and building a healthy and stable agricultural watershed water ecosystem.

[0042] Example 2

[0043] The coupled monitoring module acquires rainfall, runoff, and water level hydrological data, as well as COD, ammonia nitrogen, and total phosphorus water quality data for the entire cross-section of the small watershed in the mountainous and hilly area, according to a unified collection period. It performs outlier removal, time sequence alignment, and dimensional standardization preprocessing on the collected multi-source data to eliminate data fluctuations and deviations caused by topographic undulations and runoff scouring. It unifies data standards and collection rhythm, so that hydrological and water quality data form a unified analytical benchmark, ensuring the accuracy of subsequent model construction and extrapolation, and providing a reliable data foundation for monitoring the special hydrological conditions of mountainous watersheds. The module constructs a four-layer hydrological-water quality bidirectional coupling and correlation model, consisting of an input layer, a coupling and correlation layer, a deduction layer, and an output layer. The input layer fully loads standardized time-series hydrological and water quality data, ensuring the comprehensiveness and accuracy of the data input. The coupling and correlation layer establishes a bidirectional transmission correspondence between hydrological elements and water quality indicators, enabling a precise correlation between rapidly changing runoff, water level, and pollutant concentrations, clearly reflecting the impact of abrupt hydrological changes in mountainous watersheds on pollution distribution. The deduction layer performs time-series deductions of water quality changes based on different hydrological scenarios, fully reconstructing events such as torrential rain erosion and drought. The system identifies the unique patterns of pollution migration, scouring, and diffusion under extreme hydrological conditions. It outputs stable data on water quality trends and spatial distribution of pollution loads under different hydrological scenarios, enabling early prediction of pollution diffusion paths, peak loads, water level fluctuation risks, and areas of concentrated pollution within the watershed. This provides data support tailored to the characteristics of mountainous and hilly watersheds for subsequent hydraulic regulation and water purification, ensuring the system can quickly respond to rapidly changing hydrological conditions. It comprehensively covers the pollution monitoring needs of the entire cross-section of small watersheds, leaving no monitoring blind spots, and provides forward-looking guidance for pollution control in mountainous watersheds.

[0044] The hydraulic control module receives the water quality change trend and pollution load spatial distribution results output by the coupled monitoring module, extracts the runoff variation range, highest predicted water level, and pollution load characteristic data within the prediction period, and uses the basin's flood control safety as an unshakable rigid constraint. Combined with the flood control safety control water level, it delineates the adjustable range of the opening degree of the cascade weirs and dams, and simultaneously clarifies the constraint range of the influent flow distribution ratio for each purification unit of the water quality purification module. Within the defined adjustable range and constraint range, the optimal operating parameters are solved using the cascade weir and dam opening degree calculation formula and the influent flow distribution ratio calculation formula. This ensures that the parameters meet the safety requirements of rapid flood discharge in mountainous and hilly watersheds while allowing pollutants sufficient hydraulic retention time to ensure that the purification effect is not weakened by rapid runoff. Based on the solution results, the module generates control commands to drive the cascade weirs and dams to adjust their opening degree, and simultaneously drives the water flow distribution valve group to adjust the influent flow of each purification unit. When the highest predicted water level in the prediction results output by the coupled monitoring module exceeds the flood control safety control water level, the opening degree of the cascade weirs and dams and the influent flow of each purification unit are adjusted simultaneously. Figure 3As shown, while meeting the flood control safety water level requirements, water of no less than the preset minimum treatment flow rate is allocated from the total inflow of the river to the water purification module. The preset minimum treatment flow rate is 15% to 20% of the total design rated inflow of the water purification module. This not only quickly diverts the runoff of the basin to avoid flood risks, but also does not interrupt the pollution purification operation. This allows the water allocation to be highly compatible with the runoff velocity and water level fluctuations of the mountainous and hilly basin, giving full play to the hydraulic regulation advantages of the cascade weirs and dams, providing stable and suitable treatment conditions for the water purification module, and avoiding the impact of runoff turbulence caused by the mountainous terrain on the purification efficiency.

[0045] The water purification module receives the water to be purified from the hydraulic control module and sequentially passes through a primary interception purification unit, a secondary adsorption purification unit, a tertiary biodegradation purification unit, and a quaternary ecological stabilization purification unit along the water flow direction. Each purification unit is equipped with an independent and controllable inlet and outlet. The inlet is connected to the water flow distribution valve group of the hydraulic control module, and the outlet is connected in series to the inlet of the next purification unit, forming a stepped, closed water flow path. This perfectly adapts to the purification needs of rapid runoff in mountainous and hilly watersheds and prevents incomplete purification caused by rapid water flow. The primary interception and purification unit is filled with coarse filter media of pebbles and quartz sand to quickly intercept silt and large particulate pollutants carried by runoff, preventing clogging of subsequent purification media and ensuring the continuous and stable operation of the purification process. The secondary adsorption and purification unit is filled with modified zeolite and granular activated carbon media to efficiently adsorb ammonia nitrogen and total phosphorus pollutants carried by the runoff, rapidly reducing pollution concentration and alleviating the purification pressure brought by rapid runoff. The tertiary biodegradation and purification unit is filled with biochar and porous microbial carriers, relying on a stable microbial community to deeply degrade organic pollutants such as COD, resisting the hydraulic impact of rapid runoff, and ensuring the deep removal effect of organic pollution. The quaternary ecological stabilization and purification unit is planted with aquatic functional plants, utilizing the stress resistance and ecological regulation of the plants to complete the final removal of remaining pollutants, stabilize the ecological state of the purified water, and make the effluent suitable for the ecological environment of the mountainous watershed. Each unit relies on differentiated purification media and functional plants to intercept, adsorb, degrade, and remove COD, ammonia nitrogen, and total phosphorus pollutants in the water body step by step. It can quickly treat the rapidly flowing polluted water in mountainous and hilly watersheds and output stable purified water that meets the standards. It is fully adapted to the topography and hydrological characteristics of small watersheds in mountainous and hilly areas, maximizes the advantages of cascade purification, and effectively solves the problems of rapid pollution spread and high purification difficulty in mountainous watersheds.

[0046] The purification efficiency assessment module is stably connected to the inlet and outlet of each stage of the water purification module. Water quality monitoring points are deployed at the inlet and outlet of each purification unit, with the time step synchronized with the coupled monitoring module. This allows for the synchronous collection of COD, ammonia nitrogen, and total phosphorus concentration data from the inlet and outlet of each purification unit, adapting to the rapid hydrological changes in mountainous and hilly watersheds. This ensures real-time and accurate data collection, truly reflecting the purification effect of each purification unit under rapid runoff conditions. Based on the collected inlet and outlet water quality data, the module calculates the single-index purification efficiency of each purification unit and the overall system purification efficiency using single-index purification efficiency calculation formulas and system-wide comprehensive purification efficiency calculation formulas. This accurately quantifies the purification effectiveness of each unit under the special hydrological conditions of mountainous watersheds, clearly presenting the governance contribution of each stage. By comparing the designed purification efficiency thresholds of each purification unit with the actual calculated purification efficiency, the module identifies purification units with substandard efficiency and weak pollutant indicators, clearly pinpointing the weak links in the purification process under the special hydrological conditions of mountainous and hilly watersheds, providing precise guidance for system optimization. The module integrates real-time monitoring data, efficiency calculation results, and weakness identification conclusions to generate a complete purification efficiency assessment report and optimization direction suggestions. This provides a basis for adjusting system parameters in line with the characteristics of mountainous watersheds, enabling purification efficiency assessments to adapt to rapidly changing hydrological conditions, improving the pertinence and effectiveness of governance optimization, and avoiding ineffective adjustments that could affect system operation.

[0047] The parameter optimization module receives the purification efficiency assessment report and optimization direction suggestions output by the purification efficiency assessment module. Simultaneously, it retrieves real-time hydrological and water quality data and preset time-period prediction results from the coupled monitoring module. It performs in-depth analysis of all data to accurately pinpoint the specific location and causes of hydrological prediction deviations, hydraulic control parameter deviations, and purification efficiency shortcomings during system operation. Adapting to the characteristics of large water level fluctuations and rapid runoff changes in mountainous and hilly watersheds, it identifies the root causes of problems, ensuring that the optimization direction aligns with the actual operating conditions of the mountainous watershed. Based on the analysis results and considering future hydrological and water quality changes, the module generates optimized hydraulic control parameters and purification module operating parameters. These optimized parameters are converted into standard execution commands and simultaneously sent to the hydraulic control module and water quality purification module. This reverse adjustment controls the weir opening degree and influent flow distribution ratio of the hydraulic control module, as well as the purification medium ratio of the water quality purification module. This allows the system operating parameters to quickly adapt to the dynamic changes in hydrological and water quality in the mountainous and hilly watershed, promptly correcting operational deviations. The module completes iterative optimization of system operating parameters, realizes closed-loop autonomous control, continuously improves the system's ability to cope with rapid runoff and water level fluctuations, and ensures that the system always maintains high purification efficiency and operational stability. It is adaptable to the non-point source pollution control needs of small watersheds in mountainous and hilly areas in the long term, and can achieve optimal operation without frequent manual adjustments, ensuring the long-term effectiveness of watershed ecological purification, continuously restoring the water ecological environment of small watersheds in mountainous and hilly areas, and building a safe, stable, and healthy watershed water ecological system.

[0048] This invention addresses the challenges of small watersheds in mountainous and hilly areas, characterized by significant topographic relief, rapid runoff velocity, substantial water level fluctuations, and rapid pollution diffusion. It achieves precise interception of non-point source pollution and efficient ecological purification. The coupled monitoring module completes full-section data acquisition and hydrological-water quality coupled simulation, accurately predicting pollution diffusion and water level risks. The hydraulic control module prioritizes flood control safety, determining optimal control parameters through core calculation formulas, ensuring both flood discharge and purification flow during heavy rainfall. The water quality purification module relies on a four-stage progressive unit to withstand the impact of rapid runoff, progressively intercepting, adsorbing, and degrading pollutants. The purification efficiency assessment module calculates purification efficiency in real time, identifying shortcomings in treatment under special hydrological conditions. The parameter optimization module dynamically adjusts operating parameters, achieving closed-loop adaptive control of the system. Figure 2 As shown, the system is well-suited to the hydrological and topographical characteristics of small watersheds in mountainous and hilly areas, ensuring continuous purification and effective treatment, rapidly curbing the spread of non-point source pollution, and providing long-term restoration of the watershed's aquatic ecosystem. It offers reliable technical solutions and operational support for the treatment of non-point source pollution in small watersheds in mountainous and hilly areas.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A watershed non-point source pollution cascade interception and ecological purification system, characterized in that, The system comprises the following components: a coupling monitoring module, a hydraulic control module, a water purification module, a purification efficiency evaluation module, and a parameter optimization module; The coupled monitoring module synchronously collects rainfall, runoff, and water level hydrological data across the entire watershed section, as well as COD, ammonia nitrogen, and total phosphorus water quality data. After performing time-series alignment and standardization preprocessing on the collected data, it establishes a hydrological-water quality bidirectional coupled correlation model and outputs water quality change trends and pollution load prediction results under different hydrological scenarios. The hydraulic control module receives water quality change trends and pollution load prediction results. Taking the safety of flood control in the basin as a rigid constraint and maximizing the hydraulic residence time of pollutants as the optimization goal, it adjusts the opening degree of the cascade weirs and the proportion of inflow distribution, and distributes the water to be purified to the water purification module according to the optimized proportion. The water purification module receives the water to be purified from the hydraulic control module, and through a tiered purification structure, differentiated purification media and functional plants, it intercepts, adsorbs, degrades and removes COD, ammonia nitrogen and total phosphorus pollutants in the water step by step, and outputs purified water. The purification efficiency evaluation module is connected to the inlet and outlet of the water purification module at each stage, collects water quality data from each stage in real time, calculates the purification efficiency of a single indicator and the overall purification efficiency of the system, identifies shortcomings in purification efficiency, and generates a complete purification efficiency evaluation report and suggestions for optimization. The parameter optimization module receives the purification efficiency assessment report and optimization direction suggestions, combines them with the real-time prediction data from the coupled monitoring module, generates optimized operating parameters, and reversely adjusts the weir opening degree and influent flow distribution ratio of the hydraulic control module, as well as the purification medium ratio of the water purification module, to complete the iterative optimization of the system operating parameters.

2. The watershed non-point source pollution cascade interception and ecological purification system according to claim 1, characterized in that, The coupled monitoring module acquires hydrological data such as rainfall, runoff, and water level, as well as water quality data such as COD, ammonia nitrogen, and total phosphorus across the entire watershed during a unified collection period. It performs outlier removal, time-series alignment, and dimensional standardization preprocessing on the collected multi-source data. A hydrological-water quality bidirectional coupled correlation model is constructed, employing a four-layer structure: input layer, coupling correlation layer, deduction layer, and output layer. The input layer loads standardized time-series hydrological and water quality data; the coupling correlation layer establishes a bidirectional transmission correspondence between hydrological elements and water quality indicators; the deduction layer performs time-series deduction of water quality changes based on different hydrological scenarios; and the output layer outputs the corresponding water quality change trends and pollution load prediction results.

3. The watershed non-point source pollution cascade interception and ecological purification system according to claim 1, characterized in that, The hydraulic control module operates as follows: it receives water quality change trends and pollution load spatial distribution results, extracts the runoff variation range, highest predicted water level, and pollution load characteristic data within the predicted time period; combined with the flood control safety control water level, it delineates the adjustable range of the opening degree of the cascade weirs and the constraint range of the influent flow distribution ratio of each purification unit in the water purification module; within the defined adjustable range and constraint range, it solves for the opening degree of the cascade weirs and the influent flow distribution ratio of each purification unit; based on the solution results, it generates control commands to drive the cascade weirs to adjust their opening degree, and simultaneously drives the water flow distribution valve group to adjust the influent flow of each purification unit.

4. A watershed non-point source pollution cascade interception and ecological purification system according to claim 1 or 3, characterized in that, The calculation formulas for the ratio of the opening degree of the cascade weirs and the influent flow distribution of each purification unit in the hydraulic control module are as follows: in, The opening degree of the cascade weir dam; To ensure safe flood control, water levels must be controlled. Real-time monitoring of water levels upstream of the cascade weir dam; This refers to the total flow rate entering the water purification module; The flow coefficient of the cascade weir dam; The overflow net width of the cascade weir dam; It is the acceleration due to gravity; To advance towards the water head of the weir; The proportion of inlet water flow allocated to the i-th stage purification unit; This refers to the serial number of the cascade purification unit within the water purification module; This represents the effective design volume of the i-th stage purification unit; denoted as the pollutant degradation characteristic coefficient of the i-th stage purification unit.

5. A watershed non-point source pollution cascade interception and ecological purification system according to claim 1, characterized in that, The water purification module is arranged sequentially along the water flow direction, consisting of a primary interception purification unit, a secondary adsorption purification unit, a tertiary biodegradation purification unit, and a quaternary ecological stabilization purification unit. Each purification unit has an independent controllable inlet and outlet. The inlets are connected to the water flow distribution valve group of the hydraulic control module, and the outlets are connected in series to the inlet of the next purification unit, forming a stepped, closed water flow path. The primary interception purification unit is filled with coarse filter media such as pebbles and quartz sand. The secondary adsorption purification unit is filled with modified zeolite and granular activated carbon media. The tertiary biodegradation purification unit is filled with biochar and porous microbial carriers. The quaternary ecological stabilization purification unit is planted with aquatic functional plants.

6. A watershed non-point source pollution cascade interception and ecological purification system according to claim 1 or 5, characterized in that, The influent flow rate of each purification unit in the water purification module is controlled by the hydraulic control module according to the influent flow rate distribution ratio. The sum of the influent flow rates of each purification unit is equal to the total flow rate entering the water purification module. When the highest predicted water level in the output of the coupled monitoring module exceeds the flood control safety level, the hydraulic regulation module synchronously adjusts the opening degree of the cascade weirs and the inflow rate of each purification unit. While meeting the flood control safety level requirements, it allocates water from the total inflow of the river to the water purification module at a rate not lower than the preset minimum treatment flow rate.

7. A watershed non-point source pollution cascade interception and ecological purification system according to claim 1, characterized in that, The specific working process of the purification efficiency assessment module is as follows: water quality monitoring points are set up at the inlet and outlet of each purification unit of the water purification module, and the COD, ammonia nitrogen, and total phosphorus concentration data of the influent and effluent of each purification unit are collected synchronously with the time step of the coupled monitoring module; based on the collected influent and effluent water quality data, the single-index purification efficiency of each purification unit and the overall purification efficiency of the system are calculated; the design purification efficiency threshold of each purification unit is compared with the actual calculated purification efficiency to identify purification units with substandard efficiency and weak pollutant indicators; the real-time monitoring data, efficiency calculation results, and weak point identification conclusions are integrated to generate a purification efficiency assessment report and optimization direction suggestions.

8. A watershed non-point source pollution cascade interception and ecological purification system according to claim 1 or 7, characterized in that, The purification efficiency evaluation module calculates the single-index purification efficiency of each purification unit and the overall purification efficiency of the system, using the following formulas: in, Let J be the single-index purification efficiency of the j-th pollutant index in the i-th purification unit. This refers to the serial number of the cascade purification unit within the water purification module; This refers to the serial number of the pollutant indicator; The real-time monitoring concentration of the j-th pollutant indicator at the inlet of the i-th purification unit; The real-time monitoring concentration of the j-th pollutant indicator at the outlet of the i-th purification unit; For the overall purification efficiency of the system; is the weighting coefficient for the j-th pollutant indicator; The real-time monitoring concentration of the j-th pollutant indicator at the main inlet of the purification system; This refers to the real-time monitoring concentration of the j-th pollutant indicator at the main outlet of the purification system.

9. A watershed non-point source pollution cascade interception and ecological purification system according to claim 1, characterized in that, The specific working process of the parameter optimization module is as follows: receiving the purification efficiency assessment report and optimization direction suggestions output by the purification efficiency assessment module, and simultaneously retrieving the real-time hydrological and water quality data and the prediction results for the preset time period from the coupled monitoring module; analyzing the received full data to locate the specific location and causes of hydrological prediction deviations, hydraulic control parameter deviations, and purification efficiency shortcomings during system operation. Based on the analysis results and combined with the future hydrological and water quality changes, optimized hydraulic control parameters and purification module operating parameters are generated. The optimized parameters are converted into standard execution instructions and simultaneously sent to the hydraulic control module and water quality purification module to complete the reverse adjustment and closed-loop iteration of the system operating parameters.

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