Agricultural non-point source groundwater pollution remediation technology screening system and method

Abstract

The invention relates to the technical field of agricultural environmental protection and groundwater pollution remediation, in particular to an agricultural non-point source groundwater pollution remediation technology screening system and method, and the system comprises a barrier technology screening module, a degradation technology screening module, a removal technology screening module and a cost accounting module; the method comprises the following steps: quantitatively evaluating the pollutant blocking capability of a blocking technology to farmland infiltration through a soil hydraulics equation, screening an aeration zone efficient degradation technology by utilizing a Fick law and a Monod kinetic model, and verifying the economic feasibility of an aquifer removal technology based on a shadow engineering method and a full life cycle cost model; the method comprises the following steps: determining optimal technologies of farmland infiltration, an aeration zone and an aquifer in sequence through each module, and generating a feasible scheme in combination with cost accounting. The problems that a traditional technology is poor in adaptability and high in cost in an agricultural scene are solved, and full-chain precise screening from a pollution source to a tail end and economic and feasible repairing technology combination are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of agricultural environmental protection and groundwater pollution remediation, and specifically relates to a system and method for screening agricultural non-point source groundwater pollution remediation technology. Background Art

[0002] Remediation of groundwater pollution from agricultural non-point sources is a global challenge. Traditional industrial pollution remediation technologies, when directly applied to agricultural non-point source pollution, face core flaws such as high cost, significant disruption, and unsustainability. This failure stems from a failure to consider the unique characteristics of agricultural practices. Frequent irrigation, fertilization, and soil disturbance require remediation technologies to be compatible with farmland ecosystems, whereas the heavily intrusive nature of industrial technologies makes them incompatible with agricultural production.

[0003] Internationally, the management of agricultural non-point source pollution has long relied on source control, but effective remediation methods for already contaminated groundwater are lacking. Traditional technology screening focuses solely on technical effectiveness, ignoring the economic affordability of agricultural scenarios. The daily remediation cost acceptable to farmers is typically less than 2,000 yuan per mu, while industrial-grade remediation technology costs generally exceed 20,000 yuan per mu. This makes remediation projects difficult to implement due to a lack of investment support.

[0004] Existing groundwater remediation technology screening methods mostly rely on scoring, which doesn't address the unique migration pathways of agricultural non-point source pollution and cannot quantitatively assess the technology's suitability across various stages. Factors such as remediation time, investment costs, energy consumption, technology maturity, and secondary pollution make them unsuitable for screening agricultural non-point source pollution remediation technologies.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] In order to solve the above-mentioned technical problems existing in the prior art, the present invention provides a system and method for screening agricultural non-point source groundwater pollution remediation technology, which solves the problems of incompatibility and high cost of the prior art and can achieve accurate, economical and sustainable pollution remediation screening.

[0007] To achieve the above object, the technical solution of the present invention is as follows: In the first aspect, a system for screening agricultural non-point source groundwater pollution remediation technologies includes: Barrier technology screening module: used to evaluate the barrier capacity of technologies to pollutants infiltrating from farmland through quantitative calculations, and to screen technologies that are compatible with farmland cultivation; Degradation technology screening module: Based on the screening results of the barrier technology screening module, the module targets pollutant components with strong migration ability, evaluates the degradation ability of technologies on pollutants in the vadose zone through experimental simulation or empirical data, and selects technologies with high degradation efficiency and low environmental risks; Removal technology screening module: used to screen technologies with high removal capacity per unit time and controllable cost based on the results of the degradation technology screening module by using shadow engineering algorithm to compare the removal efficiency of pollutants in the aquifer; Cost accounting module: used to conduct full-cycle cost-effectiveness verification and generate feasible technical solutions based on the screening results of the degradation technology screening module.

[0008] Furthermore, the barrier technology screening module includes: Permeability coefficient calculation unit: used to calculate the influence of different materials on the permeability coefficient of pollutants based on the soil hydraulic equation; Nitrogen fertilizer loss assessment unit: used to calculate the nitrogen fertilizer loss reduction rate through a parameterized assessment model; Compatibility Verification Unit: used to evaluate the compatibility of technology with farmland cultivation based on a model of changes in soil physical properties.

[0009] Furthermore, the degradation technology screening module includes: Diffusion model building unit: used to build a diffusion model of vadose zone pollutants based on Fick's law; Reaction rate calculation unit: used to calculate the reaction rate constants of different degradation technologies through Monod kinetic equation; Product safety verification unit: used to verify the safety of degradation products based on isotope tracing method.

[0010] Furthermore, the removal technology screening module includes: Solute transport simulation unit: Constructs aquifer solute transport model based on Darcy's law; Removal efficiency calculation unit: calculate the pollutant removal per unit time of different removal technologies through equivalent substitution method; Economic comparison unit: Compare the economic efficiency of different technologies based on the full life cycle cost model.

[0011] Furthermore, the degradation technology screening module also includes: Residual load transfer unit: used to use the residual pollutant load output by the degradation technology screening module as the input condition for the removal technology screening module; Risk constraint unit: The environmental risk parameters evaluated by the degradation technology screening module serve as constraints for the removal technology screening module.

[0012] Furthermore, the full-cycle cost-effectiveness verification of the cost accounting module includes: Cost modeling unit: establish a full-cycle cost model including material cost, equipment cost, and operating cost; Economic benefit calculation unit: Calculate comprehensive economic benefits based on agricultural production income and environmental governance derived benefits; Investment feasibility assessment unit: Evaluate the investment feasibility of technical solutions through the net present value method.

[0013] Furthermore, it also includes: Data storage module: used to store technical parameters, evaluation results and cost data during the screening process of each module; Decision support module: used to provide technology combination optimization suggestions based on the data of the data storage module.

[0014] Furthermore, the data storage module includes: Technical parameter database: configured to store technical parameters and model parameters used by each screening module; Evaluation result database: configured to store the evaluation results and screening conclusions of each screening module; Cost database: configured to store full-cycle cost data and economic benefit data.

[0015] Furthermore, the decision support module includes: A technology combination optimization unit is configured to generate multiple technology combination solutions based on the data of the data storage module; Sensitivity analysis unit: configured to perform sensitivity analysis on different technology combination schemes and evaluate the impact of parameter changes on the results; Solution recommendation unit: configured to recommend the best solution from multiple technology combination solutions based on preset decision criteria.

[0016] Second, a method for screening agricultural non-point source groundwater pollution remediation technologies, including: S1. Determine the optimal barrier technology for farmland infiltration through the barrier technology screening module; S2. Based on the optimal barrier technology, determining the suitable degradation technology for the aeration zone through a degradation technology screening module; S3. Based on the adaptive degradation technology, determine an economically feasible removal technology for the aquifer segment through a removal technology screening module; S4. Through the cost accounting module, the optimal barrier technology, adaptive degradation technology and economically feasible removal technology are verified for their full-cycle cost-effectiveness to generate a final technical solution.

[0017] Compared with existing technologies, the above-mentioned agricultural non-point source groundwater pollution remediation technology screening system and method provided by the present invention uses soil hydraulic equations to quantitatively evaluate the barrier technology's ability to block pollutants infiltrating farmland. It uses Fick's law and the Monod kinetic model to screen for efficient degradation technologies in the vadose zone. It also verifies the economic feasibility of aquifer removal technologies based on shadow engineering methods and a life cycle cost model. It introduces tillage compatibility standards and environmental safety thresholds to ensure synergy between technology and farmland ecology. Specifically, the method determines the optimal technology for farmland infiltration, the vadose zone, and the aquifer through each module, and generates feasible solutions based on cost accounting. This system addresses the poor adaptability and high cost of traditional technologies in agricultural scenarios, achieving precise screening of the entire chain from pollution source to end point and combining economically feasible remediation technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is an architectural diagram of the agricultural non-point source groundwater pollution remediation technology screening system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0020] It should be noted that, unless otherwise specifically stated, the relative arrangements of components and steps, and numerical expressions set forth in these embodiments should not be construed as limiting the scope of the present invention.

[0021] The following description of exemplary embodiments is merely illustrative and is not intended to limit the present invention, its application, or use in any sense. Technologies, methods, and apparatus known to those skilled in the art may not be discussed in detail herein, but to the extent applicable, such technologies, methods, and apparatuses should be considered part of this specification.

[0022] Example 1 See Figure 1 The present invention provides a system for screening agricultural non-point source groundwater pollution remediation technologies. This system employs a progressive architecture, sequentially establishing barrier technology screening modules, degradation technology screening modules, and removal technology screening modules based on the migration paths of agricultural non-point source pollution: farmland infiltration, migration in the vadose zone, and accumulation in the aquifer. A cost accounting module is then used to verify the full-cycle cost-effectiveness. The modules are closely linked through data transfer and constraints; specifically, they may include: A1. Barrier Technology Screening Module: This module is used to quantitatively evaluate the barrier capacity of technologies to pollutant infiltration from farmland and screen technologies compatible with farmland cultivation. This module consists of a permeability coefficient calculation unit, a nitrogen fertilizer loss assessment unit, and a compatibility verification unit. Specifically, it includes: A11, Permeability coefficient calculation unit: used to calculate the influence of different materials on the permeability coefficient of pollutants based on the soil hydraulic equation; The Richards equation was used as the basic soil hydraulic equation, and the USDA soil texture classification parameters were introduced to calculate the effect of different barrier materials on the permeability coefficient of pollutants. Specifically, these include bentonite, biochar, and high molecular polymers. The equation is expressed as follows:

[0023] in, is the soil volume moisture content, For time, is the unsaturated hydraulic conductivity, is the pressure head, is the gravity head. The equation was solved using the numerical simulation software HYDRUS-1D to obtain the permeability coefficients of different materials under different compaction degrees and moisture contents.

[0024] A12, Nitrogen Fertilizer Loss Assessment Unit: Used to calculate the nitrogen fertilizer loss reduction rate through a parameterized assessment model; a parameterized assessment model is constructed to calculate the nitrogen fertilizer loss reduction rate of different barrier technologies based on the law of conservation of mass and the convection-diffusion equation. The specific model expression is:

[0025] in, is the nitrogen fertilizer loss concentration under unobstructed conditions, is the nitrogen fertilizer loss concentration under barrier conditions. Model parameters include soil texture, rainfall intensity, fertilizer application rate, barrier thickness, etc., which are determined through field experiments or literature data.

[0026] A13. Compatibility Verification Unit: This unit is used to evaluate the compatibility of the technology with farmland cultivation based on a soil physical property change model. A soil physical property change model is established to evaluate the impact of the barrier technology on soil bulk density, porosity, field water holding capacity, and other indicators. The model is based on the soil three-phase composition theory and is expressed as:

[0027] in, is the soil bulk density, is the soil particle density, The compatibility of the technology with farmland cultivation is determined by comparing changes in soil physical properties before and after the addition of the barrier material. If the change in soil bulk density does not exceed 10% and the change in porosity does not exceed 5%, the technology is considered compatible with farmland cultivation.

[0028] The barrier technology screening module, the first line of defense in pollution control, primarily targets infiltration into farmland, identifying technologies that can form an effective barrier layer beneath the plow bed. The results directly impact the pollutant load entering the vadose zone and provide initial conditions for the degradation technology screening module.

[0029] A2. Degradation Technology Screening Module: Based on the results of the barrier technology screening module, the module is used to evaluate the degradation capabilities of technologies for pollutants in the vadose zone through experimental simulation or empirical data, targeting pollutant components with strong migration capabilities, and to screen technologies with high degradation efficiency and low environmental risks. Specifically, this module may include: A21, Diffusion Model Construction Unit: This unit is used to construct a diffusion model of pollutants in the vadose zone based on Fick's law, describing the diffusion process of pollutants in soil pores. The specific expression is:

[0030] in, is the pollutant concentration, For time, is the diffusion coefficient in the soil. Taking into account the influence of the change of moisture content in the vadose zone on the diffusion process, the diffusion coefficient Ds is calculated using the Millington-Quirk model. The specific expression is:

[0031] in, is the diffusion coefficient of the pollutant in free water, is the soil volume moisture content, is the saturated moisture content.

[0032] A22, Reaction rate calculation unit: used to calculate the reaction rate constants of different degradation technologies using the Monod kinetic equation; the specific expression is:

[0033] in, is the reaction rate, is the maximum specific growth rate, is the substrate concentration, is the half-saturation constant, is the microbial concentration. The kinetic parameters of different degradation technologies (such as denitrifying bacteria and nano-zero-valent iron) are obtained by fitting through indoor soil column experiments or literature data. and .

[0034] A23, Product Safety Verification Unit: Used to verify the safety of degradation products based on isotope tracing. Isotope tracing (e.g., 15N labeling) is used to track the transformation pathways and product distribution of pollutants during the degradation process. The types and concentrations of degradation products are analyzed by mass spectrometers (such as GC-MS, LC-MS) to evaluate the environmental safety of the products; product safety thresholds are set, such as ammonia nitrogen concentration not exceeding 5 mg / L and nitrite concentration not exceeding 1 mg / L, to ensure that the degradation process does not cause secondary pollution.

[0035] A24, Residual Load Transfer Unit: This unit is used to provide the residual pollutant load output by the degradation technology screening module as the input condition for the removal technology screening module; based on the diffusion model and reaction rate calculation results, it determines the pollutant load remaining after degradation treatment. The residual load calculation formula is:

[0036] The initial load is the pollutant load entering the vadose zone output by the barrier technology screening module, and the degradation rate is the degradation efficiency obtained by the reaction rate calculation unit. The residual load is used as the input condition of the removal technology screening module and passed to the solute transport simulation unit.

[0037] A25, Risk Constraint Unit: The environmental risk parameters assessed in the degradation technology screening module serve as constraints for the removal technology screening module. Based on the results of the product safety verification unit, environmental risk parameters for the degradation process are extracted, including, for example, ammonia nitrogen concentration and nitrite concentration. These risk parameters are used as constraints for the removal technology screening module to ensure that subsequent removal technologies can effectively treat these potential secondary pollutants.

[0038] Based on the results of the Isolation Module, the Degradation Technology Screening Module focuses on pollutants with high mobility in the vadose zone and selects high-efficiency, low-risk degradation technologies. The residual pollutant load and environmental risk parameters output by the Isolation Module serve as inputs and constraints for the Removal Technology Screening Module.

[0039] A3. Removal Technology Screening Module: This module is used to compare the removal efficiency of pollutants in aquifers using a shadow engineering algorithm based on the results of the degradation technology screening module. By constructing a virtual remediation project, it quantifies the removal efficiency and cost of different technologies for aquifer pollutants. Specifically, it may include: A31, Solute Transport Simulation Unit: Constructs aquifer solute transport model based on Darcy's law; Based on Darcy's law and the convection-diffusion equation, an aquifer solute transport model is constructed to describe the migration process of pollutants in the aquifer. The specific expression is:

[0040] in, is the blocking factor, is the pollutant concentration, For time, is the hydrodynamic dispersion coefficient, is the actual groundwater flow velocity, and λ is the first-order reaction rate constant. The equations were solved using numerical simulation software (e.g., MODFLOW, MT3DMS) to obtain the pollutant concentration distribution and removal effectiveness under different removal technologies (e.g., extraction-treatment-recharge and in-situ chemical oxidation).

[0041] A32, Removal efficiency calculation unit: Calculate the pollutant removal per unit time of different removal technologies using the equivalent substitution method. Using the equivalent substitution method to calculate the pollutant removal per unit time of different removal technologies, for the extraction-treatment-reinjection technology, the removal calculation formula is:

[0042] in, is the amount removed per unit time, is the amount of water pumped, is the influent pollutant concentration, is the effluent pollutant concentration. For in-situ remediation technology, the equivalent removal amount per unit time is calculated by comparing the change in pollutant concentration before and after remediation, taking into account the volume of the remediation area and the remediation time.

[0043] A33, Economic Comparison Unit: Compare the economics of different technologies based on a full life cycle cost model. Calculate the total cost of different removal technologies, including material cost, equipment cost, operating cost, maintenance cost, and monitoring cost. The specific expression is:

[0044] in, is the total cost, is the cost in year i, is the discount rate. Compare the unit removal costs (yuan / kg pollutant) of different technologies and select the removal technology with the best economic efficiency.

[0045] As the end-of-pipe treatment link, the removal technology screening module selects economically feasible removal technologies suitable for the aquifer based on the results of the degradation technology screening module. Through the progressive linkage of the barrier technology screening module, the degradation technology screening module, and the removal technology screening module, a complete technology screening chain is formed.

[0046] A4. Cost accounting module: This module is used to conduct full-cycle cost-effectiveness verification and generate feasible technical solutions based on the results of the degradation technology screening module. Specifically, it may include: A41, Cost Modeling Unit: Establish a full-cycle cost model including material cost, equipment cost, and operating cost; Material costs are calculated based on the type, quantity, and market price of the required materials. Equipment costs include equipment purchase, installation, and commissioning. Operating costs include energy consumption, chemical consumption, and labor costs. Maintenance costs include equipment repairs and component replacements. Monitoring costs include regular sampling, analytical testing, and other expenses. The model takes time into account and uses a discount rate to convert future costs into present values.

[0047] A42. Economic Benefit Calculation Unit: Calculates comprehensive economic benefits based on agricultural production benefits and derived benefits from environmental governance. Production benefits include fertilizer savings, water savings, and yield increases. The formula for calculating fertilizer savings is:

[0048] in, To save fertilizer, To reduce fertilizer usage, The price of fertilizer. Water saving benefits and increased production benefits Calculated using a similar method, the comprehensive economic benefit is the sum of all benefits.

[0049] In addition, the derived benefits of environmental governance include carbon sequestration benefits ( ) and water quality improvement benefits ( ); Carbon sequestration benefits are based on the quantification of ecological carbon sequestration value based on soil carbon sequestration, and the calculation formula is:

[0050] in, is the amount of soil carbon sequestration per unit area, is the unit price of carbon trading.

[0051] The water quality improvement benefits are the quantified reduction in water treatment costs and ecological value after groundwater pollution control. The calculation formula is:

[0052] in, is the regional groundwater extraction volume, determined based on hydrological address data; and are the pollutant concentrations before and after treatment, respectively; is the unit pollutant treatment cost; The water purchase cost saved for recycled water reinjection.

[0053] The comprehensive economic benefits are calculated by combining agricultural production income and environmental governance derivative benefits. The specific calculation formula is:

[0054] Agricultural production income and environmental governance-derived benefits are calculated separately to form a full-cycle benefit matrix.

[0055] A43. Investment Feasibility Assessment Unit: Evaluate the investment feasibility of the technical solution using the net present value method. The net present value calculation formula is:

[0056] in, is the income in year t, For the Annual cost, is the discount rate. If NPV>0, the technical solution is considered economically feasible; if NPV<0, it is necessary to adjust the technical parameters or select another technology combination and re-conduct cost-effectiveness verification.

[0057] A5. Data storage module: It consists of a technical parameter database, an evaluation result database, and a cost database. Specifically, it may include: A51. Technical parameter database: stores the technical parameters and model parameters used by each screening module, including soil physical property parameters, pollutant characteristic parameters and technical performance parameters, etc.

[0058] Among them, soil physical property parameters include: bulk density, porosity, permeability, soil texture and field water holding capacity; pollutant characteristic parameters include: diffusion coefficient and reaction rate constant; technical performance parameters include: barrier layer thickness, degradation efficiency and removal rate.

[0059] Use a relational database (such as MySQL) for management, establishing data tables such as parameter tables, material tables, and model tables. Unique identifiers (such as UUIDs) link different data tables to enable cross-module parameter access and traceability. The parameter table can record various physical or chemical parameters, the material table stores material properties such as bentonite or humic acid, and the model table stores formula parameters and version information.

[0060] A52. Evaluation result database: stores the evaluation results and screening conclusions of each screening module; the barrier technology screening results include the permeability coefficient and nitrogen fertilizer loss reduction rate of the barrier technology screening module; the degradation technology screening results include degradation efficiency and product safety assessment results; the removal technology screening results include the amount of pollutants removed per unit time, economic comparison results, and technical feasibility conclusions.

[0061] The management method uses a time series database (such as InfluxDB) to store dynamic data and supports indexing by timestamp. It has a built-in trend analysis engine that automatically generates curves showing changes in evaluation results over time (such as quarterly / annual barrier efficiency fluctuation charts). At the same time, it supports docking with a GIS system to achieve spatial visualization of evaluation results.

[0062] A53. Cost database: stores full-cycle cost data, economic benefit data, and comparative analysis data; full-cycle cost data includes material costs, equipment costs, operating costs, maintenance costs, and monitoring costs; economic benefit data includes fertilizer-saving benefits, water-saving benefits, increased production benefits, and carbon sequestration benefits; comparative analysis data includes: total cost comparison of different technology combinations, cost composition ratios, and payback period calculation results.

[0063] The management method uses data warehouse technology (such as Hive) to achieve hierarchical storage of massive data, support multi-dimensional analysis (such as by region / technology type / time dimension), generate cost-benefit reports (such as annual cost trend table, technology combination ROI comparison chart); integrate data visualization tools (such as Tableau), dynamically display cost tree structure diagrams, profit trend curves, etc.

[0064] A6. Decision support module: It consists of a technology combination optimization unit, a sensitivity analysis unit, and a solution recommendation unit. Specifically, it may include: A61, Technology combination optimization unit: Based on the data of the data storage module, a multi-objective optimization algorithm (such as NSGA-II) is used to generate multiple technology combination solutions.

[0065] Optimization objectives include maximizing pollutant removal efficiency, minimizing costs, minimizing environmental risks, etc., and constraints include technical compatibility, processing capacity, investment budget, etc.

[0066] Through iterative calculation of the algorithm, the Pareto optimal solution set is obtained, and each solution represents a feasible technology combination plan.

[0067] A62, Sensitivity Analysis Unit: Conduct sensitivity analysis on different technology combination schemes to evaluate the impact of changes in key parameters (such as soil permeability, degradation rate constant, discount rate) on the results.

[0068] The Monte Carlo simulation method is used to generate the probability distribution of parameters through random sampling, and the sensitivity coefficient of each parameter to the objective function is calculated.

[0069] Based on the results of sensitivity analysis, key factors affecting the performance of technical solutions are identified to provide a basis for solution optimization.

[0070] A63, Scheme Recommendation Unit: Based on the preset decision-making criteria, including priority on economic benefits, priority on environmental benefits and optimal comprehensive benefits, the optimal scheme is recommended from a variety of technical combination schemes.

[0071] For the decision-making criteria that prioritize economic benefits, the option with the largest NPV is selected; for the decision-making criteria that prioritize environmental benefits, the option with the highest pollutant removal efficiency and the lowest environmental risk is selected; for the decision-making criteria that prioritize the best comprehensive benefits, the analytic hierarchy process (AHP) is used to comprehensively consider multiple indicators, calculate the comprehensive scores of each option, and select the option with the highest score.

[0072] Example 2 See Figure 1 The present invention provides a method for screening agricultural non-point source groundwater pollution remediation technology, which specifically includes the following steps: S1. Use the barrier technology screening module to determine the optimal barrier technology for farmland infiltration. Collect barrier materials / technologies suitable for farmland, including bentonite, kaolin, humic acid, barrier membranes, and lime powder. Calculate the impact of materials on pollutant permeability using the Richards equation and, combined with field data from the North China Plain, quantify the reduction in nitrogen fertilizer loss. See Table 1: Table 1 Calculation results

[0073] When 2000kg of bentonite or kaolin is evenly applied per mu, after 3-5 years of cultivation, the two can be deposited on the plow bottom to form a barrier layer, which can reduce nitrogen fertilizer loss by 40% (about 10kg nitrogen / year), increase crop nitrogen fertilizer absorption by 5kg / year, and save 50 cubic meters of irrigation water / year, without obvious side effects; while when 500kg of humic acid is applied, 100kg of it is lost, 300kg is mixed with soil particles, and 100kg is deposited on the plow bottom, which can only reduce nitrogen fertilizer loss by 20% (about 5kg nitrogen / year), increase crop nitrogen fertilizer absorption by 2kg / year, and there is a risk of crop diseases caused by high-amount application.

[0074] In summary, bentonite and kaolin are significantly superior to other technologies in terms of barrier capacity, environmental adaptability, operational feasibility and economy, and are the best choices.

[0075] S2. Based on the optimal barrier technology, the degradation technology screening module is used to determine the suitable degradation technology for the aeration zone. Among agricultural non-point source pollution, nitrate has the strongest migration ability and is selected as the target pollutant for degradation technology screening.

[0076] In the screening of degradation technologies, a comparison was made between denitrifying bacteria and nano-iron for nitrate, the most mobile form of agricultural non-point source pollution. Denitrifying bacteria cost 100 yuan per ton, with a dosage of 10 tons per mu (including a 10 yuan per ton dosage fee). The denitrifying bacteria solution has an active period of three months, and with two applications per year (during the wheat and corn growing season), it can reduce 99% of infiltrating nitrate to nitrogen gas or ammonia nitrogen. The annual cost is 2,200 yuan per mu, and there is no disturbance to farming. Nano-iron, however, is expensive (more than 10 times the cost of the bacteria solution), has difficulty accurately reducing nitrate to nitrogen gas, and easily generates ammonia nitrogen, causing secondary pollution, presenting significant technical disadvantages. After screening, denitrifying bacteria became the only viable technology due to its low cost, high efficiency, and no impact on agricultural production.

[0077] S3. Based on the adaptive degradation technology, determine the economically feasible removal technology for the aquifer link through the removal technology screening module; screen the aquifer remediation technology with high removal efficiency per unit time and controllable cost.

[0078] Using a shadow engineering approach, four aquifer remediation technologies were evaluated for a 667 m² farmland, a 10 m thick aquifer, and a nitrate nitrogen concentration of 100 mg / L. The extraction and treatment technology, through the installation of four 500 m³ / day pumping wells, can reduce nitrate concentrations by over 50% within two days, at a pumping cost of only 50 yuan per mu (a new well network costs 10,000 yuan per mu and is sustainable), and the extracted fluid can be reused for irrigation. The in-situ reduction / denitrification technology suffers from high chemical costs and an efficiency of less than 40% (it only partially converts nitrate and consumes the agent quickly). The in-situ isolation technology has a construction cost exceeding 20,000 yuan per mu and damages farmland, making it technically and economically unfeasible. A comparison of efficiency and cost revealed that the extraction and treatment technology offers significantly higher removal rates per unit time. Reusing the existing well network significantly reduces infrastructure costs, making it the optimal solution, particularly suitable for areas covered by existing well networks.

[0079] S4. Through the cost accounting module, the optimal barrier technology, adaptive degradation technology and economically feasible removal technology are verified for their full-cycle cost-effectiveness to generate a final technical solution.

[0080] In summary, the present invention has the following advantages: (1) Through the adaptability of soil hydraulic equation quantitative assessment technology in various links, the defect of traditional methods that ignore the migration mechanism of agricultural pollution is solved; (2) Establish a single-link cost quantification model and a comprehensive cost decision-making mechanism to eliminate over-budget technologies and select technology combinations that are more cost-effective than traditional solutions; (3) Set farming compatibility thresholds and environmental safety indicators to ensure the synergy between technology and farmland ecology.

[0081] The above specific embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solutions of the invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, and all of these should be included in the scope of the claims of the present invention.

Claims

1. A screening system for agricultural non-point source groundwater pollution remediation technology, characterized in that: include: Barrier technology screening module: used to evaluate the barrier capacity of technologies to pollutants infiltrating from farmland through quantitative calculations, and to screen technologies that are compatible with farmland cultivation; Degradation technology screening module: Based on the screening results of the barrier technology screening module, the module targets pollutant components with strong migration ability, evaluates the degradation ability of technologies on pollutants in the vadose zone through experimental simulation or empirical data, and selects technologies with high degradation efficiency and low environmental risks; Removal technology screening module: used to screen technologies with high removal capacity per unit time and controllable cost based on the results of the degradation technology screening module by using shadow engineering algorithm to compare the removal efficiency of pollutants in the aquifer; Cost accounting module: used to conduct full-cycle cost-effectiveness verification and generate feasible technical solutions based on the screening results of the degradation technology screening module.

2. The agricultural non-point source groundwater pollution remediation technology screening system according to claim 1 is characterized in that: The barrier technology screening module includes: Permeability coefficient calculation unit: used to calculate the influence of different materials on the permeability coefficient of pollutants based on the soil hydraulic equation; Nitrogen fertilizer loss assessment unit: used to calculate the nitrogen fertilizer loss reduction rate through a parameterized assessment model; Compatibility Verification Unit: used to evaluate the compatibility of technology with farmland cultivation based on a model of changes in soil physical properties.

3. The agricultural non-point source groundwater pollution remediation technology screening system according to claim 1 is characterized in that: The degradation technology screening module includes: Diffusion model building unit: used to build a diffusion model of vadose zone pollutants based on Fick's law; Reaction rate calculation unit: used to calculate the reaction rate constants of different degradation technologies through Monod kinetic equation; Product safety verification unit: used to verify the safety of degradation products based on isotope tracing method.

4. The agricultural non-point source groundwater pollution remediation technology screening system according to claim 1 is characterized in that: The removal technology screening module includes: Solute transport simulation unit: Constructs aquifer solute transport model based on Darcy's law; Removal efficiency calculation unit: Calculate the pollutant removal per unit time of different removal technologies through equivalent substitution method; Economic comparison unit: Compare the economic efficiency of different technologies based on the full life cycle cost model.

5. The agricultural non-point source groundwater pollution remediation technology screening system according to claim 1 is characterized in that: The degradation technology screening module also includes: Residual load transfer unit: used to use the residual pollutant load output by the degradation technology screening module as the input condition for the removal technology screening module; Risk constraint unit: The environmental risk parameters evaluated by the degradation technology screening module serve as constraints for the removal technology screening module.

6. The agricultural non-point source groundwater pollution remediation technology screening system according to claim 1 is characterized in that: The full-cycle cost-effectiveness verification of the cost accounting module includes: Cost modeling unit: establish a full-cycle cost model including material cost, equipment cost, and operating cost; Economic benefit calculation unit: based on agricultural production income and environmental governance derived benefits and calculation of comprehensive economic benefits; Investment feasibility assessment unit: Evaluate the investment feasibility of technical solutions through the net present value method.

7. The agricultural non-point source groundwater pollution remediation technology screening system according to claim 1 is characterized in that: Also includes: Data storage module: used to store technical parameters, evaluation results and cost data during the screening process of each module; Decision support module: used to provide technology combination optimization suggestions based on the data of the data storage module.

8. The agricultural non-point source groundwater pollution remediation technology screening system according to claim 7 is characterized in that: The data storage module includes: Technical parameter database: configured to store technical parameters and model parameters used by each screening module; Evaluation result database: configured to store the evaluation results and screening conclusions of each screening module; Cost database: configured to store full-cycle cost data and economic benefit data.

9. The agricultural non-point source groundwater pollution remediation technology screening system according to claim 7, characterized in that: The decision support module includes: A technology combination optimization unit is configured to generate multiple technology combination solutions based on the data of the data storage module; Sensitivity analysis unit: configured to perform sensitivity analysis on different technology combination schemes and evaluate the impact of parameter changes on the results; Solution recommendation unit: configured to recommend the best solution from multiple technology combination solutions based on preset decision criteria.

10. A method for screening agricultural non-point source groundwater pollution remediation technology, characterized in that: include: S1. Determine the optimal barrier technology for farmland infiltration through the barrier technology screening module; S2. Based on the optimal barrier technology, determining the suitable degradation technology for the aeration zone through a degradation technology screening module; S3. Based on the adaptive degradation technology, determine an economically feasible removal technology for the aquifer segment through a removal technology screening module; S4. Through the cost accounting module, the optimal barrier technology, adaptive degradation technology and economically feasible removal technology are verified for their full-cycle cost-effectiveness to generate a final technical solution.

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